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    <link:label id="lab_us-gaap_AdditionalPaidInCapitalMember_9725C9E5136FD2DA951EBE2CAE56B45B_terseLabel_en-US" xlink:label="lab_us-gaap_AdditionalPaidInCapitalMember_9725C9E5136FD2DA951EBE2CAE56B45B" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Additional Paid-in Capital</link:label>
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    <link:label id="lab_us-gaap_VestingAxis_FCC69068C06D5F38AF7FBEA374A238B5_label_en-US" xlink:label="lab_us-gaap_VestingAxis_FCC69068C06D5F38AF7FBEA374A238B5" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Vesting [Axis]</link:label>
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    <link:label id="lab_us-gaap_VestingDomain_D1C67AFE5EC6E37778A5BEA374AA0CAB_terseLabel_en-US" xlink:label="lab_us-gaap_VestingDomain_D1C67AFE5EC6E37778A5BEA374AA0CAB" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Vesting [Domain]</link:label>
    <link:label id="lab_us-gaap_VestingDomain_D1C67AFE5EC6E37778A5BEA374AA0CAB_label_en-US" xlink:label="lab_us-gaap_VestingDomain_D1C67AFE5EC6E37778A5BEA374AA0CAB" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Vesting [Domain]</link:label>
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    <link:label id="lab_us-gaap_ShareBasedCompensationAwardTrancheOneMember_6B14E772FD5D22FFE714BEA3A7802B43_terseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationAwardTrancheOneMember_6B14E772FD5D22FFE714BEA3A7802B43" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Vested in 2017</link:label>
    <link:label id="lab_us-gaap_ShareBasedCompensationAwardTrancheOneMember_6B14E772FD5D22FFE714BEA3A7802B43_label_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationAwardTrancheOneMember_6B14E772FD5D22FFE714BEA3A7802B43" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-based Compensation Award, Tranche One [Member]</link:label>
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    <link:label id="lab_us-gaap_ShareBasedCompensationAwardTrancheTwoMember_B806DE24C76A94312FDFBEA3C6132076_label_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationAwardTrancheTwoMember_B806DE24C76A94312FDFBEA3C6132076" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-based Compensation Award, Tranche Two [Member]</link:label>
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    <link:label id="lab_us-gaap_ShareBasedCompensationAwardTrancheThreeMember_9630E5B74E46272733A9BEA3E008D621_label_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationAwardTrancheThreeMember_9630E5B74E46272733A9BEA3E008D621" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-based Compensation Award, Tranche Three [Member]</link:label>
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    <link:label id="lab_us-gaap_PlanNameDomain_2B6C9EDD823248911905BE2CAC97CC2C_label_en-US" xlink:label="lab_us-gaap_PlanNameDomain_2B6C9EDD823248911905BE2CAC97CC2C" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Plan Name [Domain]</link:label>
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    <link:label id="lab_clh_SafetyKleenMember_C6F2F3026A55488C97F2BE2CAC7F39B3_documentation_en-US" xlink:label="lab_clh_SafetyKleenMember_C6F2F3026A55488C97F2BE2CAC7F39B3" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Safety-Kleen [Member]</link:label>
    <link:loc xlink:href="clh-20171231.xsd#clh_SafetyKleenMember" xlink:label="loc_clh_SafetyKleenMember_C6F2F3026A55488C97F2BE2CAC7F39B3" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_clh_SafetyKleenMember_C6F2F3026A55488C97F2BE2CAC7F39B3" xlink:to="lab_clh_SafetyKleenMember_C6F2F3026A55488C97F2BE2CAC7F39B3" xlink:type="arc" />
    <link:label id="lab_us-gaap_LossContingenciesLineItems_C7310215CD71AE17D5B8BE2CAC7FA95F_terseLabel_en-US" xlink:label="lab_us-gaap_LossContingenciesLineItems_C7310215CD71AE17D5B8BE2CAC7FA95F" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Loss Contingencies [Line Items]</link:label>
    <link:label id="lab_us-gaap_LossContingenciesLineItems_C7310215CD71AE17D5B8BE2CAC7FA95F_label_en-US" xlink:label="lab_us-gaap_LossContingenciesLineItems_C7310215CD71AE17D5B8BE2CAC7FA95F" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Loss Contingencies [Line Items]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LossContingenciesLineItems" xlink:label="loc_us-gaap_LossContingenciesLineItems_C7310215CD71AE17D5B8BE2CAC7FA95F" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LossContingenciesLineItems_C7310215CD71AE17D5B8BE2CAC7FA95F" xlink:to="lab_us-gaap_LossContingenciesLineItems_C7310215CD71AE17D5B8BE2CAC7FA95F" xlink:type="arc" />
    <link:label id="lab_clh_LegalAndAdministrativeProceedingsAbstract_D2EC9537089297D07514BE2CAC7FD1D9_terseLabel_en-US" xlink:label="lab_clh_LegalAndAdministrativeProceedingsAbstract_D2EC9537089297D07514BE2CAC7FD1D9" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Legal and Administrative Proceedings</link:label>
    <link:label id="lab_clh_LegalAndAdministrativeProceedingsAbstract_D2EC9537089297D07514BE2CAC7FD1D9_label_en-US" xlink:label="lab_clh_LegalAndAdministrativeProceedingsAbstract_D2EC9537089297D07514BE2CAC7FD1D9" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Legal and Administrative Proceedings [Abstract]</link:label>
    <link:label id="lab_clh_LegalAndAdministrativeProceedingsAbstract_D2EC9537089297D07514BE2CAC7FD1D9_documentation_en-US" xlink:label="lab_clh_LegalAndAdministrativeProceedingsAbstract_D2EC9537089297D07514BE2CAC7FD1D9" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">-- None. No documentation exists for this element. --</link:label>
    <link:loc xlink:href="clh-20171231.xsd#clh_LegalAndAdministrativeProceedingsAbstract" xlink:label="loc_clh_LegalAndAdministrativeProceedingsAbstract_D2EC9537089297D07514BE2CAC7FD1D9" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_clh_LegalAndAdministrativeProceedingsAbstract_D2EC9537089297D07514BE2CAC7FD1D9" xlink:to="lab_clh_LegalAndAdministrativeProceedingsAbstract_D2EC9537089297D07514BE2CAC7FD1D9" xlink:type="arc" />
    <link:label id="lab_us-gaap_LossContingencyAccrualAtCarryingValue_B6A8B410EA2BB0DCFFFCBE2CAC7FD9CB_terseLabel_en-US" xlink:label="lab_us-gaap_LossContingencyAccrualAtCarryingValue_B6A8B410EA2BB0DCFFFCBE2CAC7FD9CB" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Reserves</link:label>
    <link:label id="lab_us-gaap_LossContingencyAccrualAtCarryingValue_B6A8B410EA2BB0DCFFFCBE2CAC7FD9CB_label_en-US" xlink:label="lab_us-gaap_LossContingencyAccrualAtCarryingValue_B6A8B410EA2BB0DCFFFCBE2CAC7FD9CB" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Loss Contingency Accrual</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LossContingencyAccrualAtCarryingValue" xlink:label="loc_us-gaap_LossContingencyAccrualAtCarryingValue_B6A8B410EA2BB0DCFFFCBE2CAC7FD9CB" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LossContingencyAccrualAtCarryingValue_B6A8B410EA2BB0DCFFFCBE2CAC7FD9CB" xlink:to="lab_us-gaap_LossContingencyAccrualAtCarryingValue_B6A8B410EA2BB0DCFFFCBE2CAC7FD9CB" xlink:type="arc" />
    <link:label id="lab_clh_LossContingencyAccrualAtCarryingValuePotentialAdditionalLiability_9EBEC30CB1E4080A3ECEBE2CAC800ADC_verboseLabel_en-US" xlink:label="lab_clh_LossContingencyAccrualAtCarryingValuePotentialAdditionalLiability_9EBEC30CB1E4080A3ECEBE2CAC800ADC" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Possible increase in legal and administrative proceedings</link:label>
    <link:label id="lab_clh_LossContingencyAccrualAtCarryingValuePotentialAdditionalLiability_9EBEC30CB1E4080A3ECEBE2CAC800ADC_label_en-US" xlink:label="lab_clh_LossContingencyAccrualAtCarryingValuePotentialAdditionalLiability_9EBEC30CB1E4080A3ECEBE2CAC800ADC" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Loss Contingency Accrual at Carrying Value Potential Additional Liability</link:label>
    <link:label id="lab_clh_LossContingencyAccrualAtCarryingValuePotentialAdditionalLiability_9EBEC30CB1E4080A3ECEBE2CAC800ADC_documentation_en-US" xlink:label="lab_clh_LossContingencyAccrualAtCarryingValuePotentialAdditionalLiability_9EBEC30CB1E4080A3ECEBE2CAC800ADC" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">The amount as of the balance sheet date of potential needed increase in the loss contingency reserves.</link:label>
    <link:loc xlink:href="clh-20171231.xsd#clh_LossContingencyAccrualAtCarryingValuePotentialAdditionalLiability" xlink:label="loc_clh_LossContingencyAccrualAtCarryingValuePotentialAdditionalLiability_9EBEC30CB1E4080A3ECEBE2CAC800ADC" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_clh_LossContingencyAccrualAtCarryingValuePotentialAdditionalLiability_9EBEC30CB1E4080A3ECEBE2CAC800ADC" xlink:to="lab_clh_LossContingencyAccrualAtCarryingValuePotentialAdditionalLiability_9EBEC30CB1E4080A3ECEBE2CAC800ADC" xlink:type="arc" />
    <link:label id="lab_clh_LossContingencyRangeOfLoss_F92EB11FA380B485F970BE2CAC806BF7_terseLabel_en-US" xlink:label="lab_clh_LossContingencyRangeOfLoss_F92EB11FA380B485F970BE2CAC806BF7" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Reserves relating to legal and administrative proceedings</link:label>
    <link:label id="lab_clh_LossContingencyRangeOfLoss_F92EB11FA380B485F970BE2CAC806BF7_label_en-US" xlink:label="lab_clh_LossContingencyRangeOfLoss_F92EB11FA380B485F970BE2CAC806BF7" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Loss Contingency, Range of Loss</link:label>
    <link:label id="lab_clh_LossContingencyRangeOfLoss_F92EB11FA380B485F970BE2CAC806BF7_documentation_en-US" xlink:label="lab_clh_LossContingencyRangeOfLoss_F92EB11FA380B485F970BE2CAC806BF7" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">The estimated minimum amount of possible loss from the federal and state enforcement actions.</link:label>
    <link:loc xlink:href="clh-20171231.xsd#clh_LossContingencyRangeOfLoss" xlink:label="loc_clh_LossContingencyRangeOfLoss_F92EB11FA380B485F970BE2CAC806BF7" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_clh_LossContingencyRangeOfLoss_F92EB11FA380B485F970BE2CAC806BF7" xlink:to="lab_clh_LossContingencyRangeOfLoss_F92EB11FA380B485F970BE2CAC806BF7" xlink:type="arc" />
    <link:label id="lab_clh_NumberOfPermitsIssuedByGovernmentToDumpOrganicLiquid_D40A882E66AAA713A55DBE2CAC80D3DC_terseLabel_en-US" xlink:label="lab_clh_NumberOfPermitsIssuedByGovernmentToDumpOrganicLiquid_D40A882E66AAA713A55DBE2CAC80D3DC" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Number of permits issued by government, for dumping organic liquid</link:label>
    <link:label id="lab_clh_NumberOfPermitsIssuedByGovernmentToDumpOrganicLiquid_D40A882E66AAA713A55DBE2CAC80D3DC_label_en-US" xlink:label="lab_clh_NumberOfPermitsIssuedByGovernmentToDumpOrganicLiquid_D40A882E66AAA713A55DBE2CAC80D3DC" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Number of Permits Issued by Government to Dump Organic Liquid</link:label>
    <link:label id="lab_clh_NumberOfPermitsIssuedByGovernmentToDumpOrganicLiquid_D40A882E66AAA713A55DBE2CAC80D3DC_documentation_en-US" xlink:label="lab_clh_NumberOfPermitsIssuedByGovernmentToDumpOrganicLiquid_D40A882E66AAA713A55DBE2CAC80D3DC" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">The number of permits that are granted by the government in relation to environmental liabilities.</link:label>
    <link:loc xlink:href="clh-20171231.xsd#clh_NumberOfPermitsIssuedByGovernmentToDumpOrganicLiquid" xlink:label="loc_clh_NumberOfPermitsIssuedByGovernmentToDumpOrganicLiquid_D40A882E66AAA713A55DBE2CAC80D3DC" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_clh_NumberOfPermitsIssuedByGovernmentToDumpOrganicLiquid_D40A882E66AAA713A55DBE2CAC80D3DC" xlink:to="lab_clh_NumberOfPermitsIssuedByGovernmentToDumpOrganicLiquid_D40A882E66AAA713A55DBE2CAC80D3DC" xlink:type="arc" />
    <link:label id="lab_clh_NumberOfNeighboringMunicipalitiesFilingSeparateLegalProceedings_D4F3E639237A9D0CCFD8BE2CAC80E457_terseLabel_en-US" xlink:label="lab_clh_NumberOfNeighboringMunicipalitiesFilingSeparateLegalProceedings_D4F3E639237A9D0CCFD8BE2CAC80E457" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Number of neighboring municipalities filing separate legal proceedings against the Mercier subsidiary and the government of Quebec</link:label>
    <link:label id="lab_clh_NumberOfNeighboringMunicipalitiesFilingSeparateLegalProceedings_D4F3E639237A9D0CCFD8BE2CAC80E457_label_en-US" xlink:label="lab_clh_NumberOfNeighboringMunicipalitiesFilingSeparateLegalProceedings_D4F3E639237A9D0CCFD8BE2CAC80E457" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Number of Neighboring Municipalities Filing Separate Legal Proceedings</link:label>
    <link:label id="lab_clh_NumberOfNeighboringMunicipalitiesFilingSeparateLegalProceedings_D4F3E639237A9D0CCFD8BE2CAC80E457_documentation_en-US" xlink:label="lab_clh_NumberOfNeighboringMunicipalitiesFilingSeparateLegalProceedings_D4F3E639237A9D0CCFD8BE2CAC80E457" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">This element represents the number of municipalities other than Ville Mercier that filed legal proceedings against the Mercier Subsidiary.</link:label>
    <link:loc xlink:href="clh-20171231.xsd#clh_NumberOfNeighboringMunicipalitiesFilingSeparateLegalProceedings" xlink:label="loc_clh_NumberOfNeighboringMunicipalitiesFilingSeparateLegalProceedings_D4F3E639237A9D0CCFD8BE2CAC80E457" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_clh_NumberOfNeighboringMunicipalitiesFilingSeparateLegalProceedings_D4F3E639237A9D0CCFD8BE2CAC80E457" xlink:to="lab_clh_NumberOfNeighboringMunicipalitiesFilingSeparateLegalProceedings_D4F3E639237A9D0CCFD8BE2CAC80E457" xlink:type="arc" />
    <link:label id="lab_clh_LossContingencyGeneralDamagesSoughtValue_42FE1CE870FBF7E0B6D4BE2CAC805A1F_terseLabel_en-US" xlink:label="lab_clh_LossContingencyGeneralDamagesSoughtValue_42FE1CE870FBF7E0B6D4BE2CAC805A1F" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">General damages sought</link:label>
    <link:label id="lab_clh_LossContingencyGeneralDamagesSoughtValue_42FE1CE870FBF7E0B6D4BE2CAC805A1F_label_en-US" xlink:label="lab_clh_LossContingencyGeneralDamagesSoughtValue_42FE1CE870FBF7E0B6D4BE2CAC805A1F" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Loss Contingency, General Damages Sought, Value</link:label>
    <link:label id="lab_clh_LossContingencyGeneralDamagesSoughtValue_42FE1CE870FBF7E0B6D4BE2CAC805A1F_documentation_en-US" xlink:label="lab_clh_LossContingencyGeneralDamagesSoughtValue_42FE1CE870FBF7E0B6D4BE2CAC805A1F" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Loss Contingency, General Damages Sought, Value</link:label>
    <link:loc xlink:href="clh-20171231.xsd#clh_LossContingencyGeneralDamagesSoughtValue" xlink:label="loc_clh_LossContingencyGeneralDamagesSoughtValue_42FE1CE870FBF7E0B6D4BE2CAC805A1F" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_clh_LossContingencyGeneralDamagesSoughtValue_42FE1CE870FBF7E0B6D4BE2CAC805A1F" xlink:to="lab_clh_LossContingencyGeneralDamagesSoughtValue_42FE1CE870FBF7E0B6D4BE2CAC805A1F" xlink:type="arc" />
    <link:label id="lab_clh_LossContingencyPunitiveDamagesSoughtValue_3E5A80323F2127D95B00BE2CAC80E800_terseLabel_en-US" xlink:label="lab_clh_LossContingencyPunitiveDamagesSoughtValue_3E5A80323F2127D95B00BE2CAC80E800" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Punitive damages sought</link:label>
    <link:label id="lab_clh_LossContingencyPunitiveDamagesSoughtValue_3E5A80323F2127D95B00BE2CAC80E800_label_en-US" xlink:label="lab_clh_LossContingencyPunitiveDamagesSoughtValue_3E5A80323F2127D95B00BE2CAC80E800" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Loss Contingency, Punitive Damages Sought, Value</link:label>
    <link:label id="lab_clh_LossContingencyPunitiveDamagesSoughtValue_3E5A80323F2127D95B00BE2CAC80E800_documentation_en-US" xlink:label="lab_clh_LossContingencyPunitiveDamagesSoughtValue_3E5A80323F2127D95B00BE2CAC80E800" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Loss Contingency, Punitive Damages Sought, Value</link:label>
    <link:loc xlink:href="clh-20171231.xsd#clh_LossContingencyPunitiveDamagesSoughtValue" xlink:label="loc_clh_LossContingencyPunitiveDamagesSoughtValue_3E5A80323F2127D95B00BE2CAC80E800" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_clh_LossContingencyPunitiveDamagesSoughtValue_3E5A80323F2127D95B00BE2CAC80E800" xlink:to="lab_clh_LossContingencyPunitiveDamagesSoughtValue_3E5A80323F2127D95B00BE2CAC80E800" xlink:type="arc" />
    <link:label id="lab_us-gaap_LossContingencyPendingClaimsNumber_C8B90D2C96588C013C8EBE2CAC80A644_terseLabel_en-US" xlink:label="lab_us-gaap_LossContingencyPendingClaimsNumber_C8B90D2C96588C013C8EBE2CAC80A644" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Number of proceedings</link:label>
    <link:label id="lab_us-gaap_LossContingencyPendingClaimsNumber_C8B90D2C96588C013C8EBE2CAC80A644_label_en-US" xlink:label="lab_us-gaap_LossContingencyPendingClaimsNumber_C8B90D2C96588C013C8EBE2CAC80A644" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Loss Contingency, Pending Claims, Number</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LossContingencyPendingClaimsNumber" xlink:label="loc_us-gaap_LossContingencyPendingClaimsNumber_C8B90D2C96588C013C8EBE2CAC80A644" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LossContingencyPendingClaimsNumber_C8B90D2C96588C013C8EBE2CAC80A644" xlink:to="lab_us-gaap_LossContingencyPendingClaimsNumber_C8B90D2C96588C013C8EBE2CAC80A644" xlink:type="arc" />
    <link:label id="lab_us-gaap_LossContingencyClaimsSettledAndDismissedNumber_3701819E0D91DDC7982DBE2CAC806055_terseLabel_en-US" xlink:label="lab_us-gaap_LossContingencyClaimsSettledAndDismissedNumber_3701819E0D91DDC7982DBE2CAC806055" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Loss contingency, claims settled and dismissed, claims</link:label>
    <link:label id="lab_us-gaap_LossContingencyClaimsSettledAndDismissedNumber_3701819E0D91DDC7982DBE2CAC806055_label_en-US" xlink:label="lab_us-gaap_LossContingencyClaimsSettledAndDismissedNumber_3701819E0D91DDC7982DBE2CAC806055" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Loss Contingency, Claims Settled and Dismissed, Number</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LossContingencyClaimsSettledAndDismissedNumber" xlink:label="loc_us-gaap_LossContingencyClaimsSettledAndDismissedNumber_3701819E0D91DDC7982DBE2CAC806055" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LossContingencyClaimsSettledAndDismissedNumber_3701819E0D91DDC7982DBE2CAC806055" xlink:to="lab_us-gaap_LossContingencyClaimsSettledAndDismissedNumber_3701819E0D91DDC7982DBE2CAC806055" xlink:type="arc" />
    <link:label id="lab_us-gaap_IncomeTaxDisclosureAbstract_69B3C8EB6923B21A0C9D32A7158ECF4D_label_en-US" xlink:label="lab_us-gaap_IncomeTaxDisclosureAbstract_69B3C8EB6923B21A0C9D32A7158ECF4D" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Income Tax Disclosure [Abstract]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncomeTaxDisclosureAbstract" xlink:label="loc_us-gaap_IncomeTaxDisclosureAbstract_69B3C8EB6923B21A0C9D32A7158ECF4D" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncomeTaxDisclosureAbstract_69B3C8EB6923B21A0C9D32A7158ECF4D" xlink:to="lab_us-gaap_IncomeTaxDisclosureAbstract_69B3C8EB6923B21A0C9D32A7158ECF4D" xlink:type="arc" />
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    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_clh_TechnicalServicesMember_7FC9FADC33A621CEA3F132A71589F37A" xlink:to="lab_clh_TechnicalServicesMember_7FC9FADC33A621CEA3F132A71589F37A" xlink:type="arc" />
    <link:label id="lab_clh_IndustrialandFieldServicesMember_E6AE66D88A0D2B92187B32A715895963_verboseLabel_en-US" xlink:label="lab_clh_IndustrialandFieldServicesMember_E6AE66D88A0D2B92187B32A715895963" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Industrial and Field Services</link:label>
    <link:label id="lab_clh_IndustrialandFieldServicesMember_E6AE66D88A0D2B92187B32A715895963_label_en-US" xlink:label="lab_clh_IndustrialandFieldServicesMember_E6AE66D88A0D2B92187B32A715895963" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Industrial and Field Services [Member]</link:label>
    <link:label id="lab_clh_IndustrialandFieldServicesMember_E6AE66D88A0D2B92187B32A715895963_documentation_en-US" xlink:label="lab_clh_IndustrialandFieldServicesMember_E6AE66D88A0D2B92187B32A715895963" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">This element represents the Industrial and Field Services segment of the entity.</link:label>
    <link:loc xlink:href="clh-20171231.xsd#clh_IndustrialandFieldServicesMember" xlink:label="loc_clh_IndustrialandFieldServicesMember_E6AE66D88A0D2B92187B32A715895963" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_clh_IndustrialandFieldServicesMember_E6AE66D88A0D2B92187B32A715895963" xlink:to="lab_clh_IndustrialandFieldServicesMember_E6AE66D88A0D2B92187B32A715895963" xlink:type="arc" />
    <link:label id="lab_clh_OilGasandLodgingSegmentMember_E5D0A51364E0A6F56DB732A7158A0FF9_terseLabel_en-US" xlink:label="lab_clh_OilGasandLodgingSegmentMember_E5D0A51364E0A6F56DB732A7158A0FF9" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Oil, Gas and Lodging Services</link:label>
    <link:label id="lab_clh_OilGasandLodgingSegmentMember_E5D0A51364E0A6F56DB732A7158A0FF9_label_en-US" xlink:label="lab_clh_OilGasandLodgingSegmentMember_E5D0A51364E0A6F56DB732A7158A0FF9" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Oil, Gas, and Lodging Segment [Member]</link:label>
    <link:label id="lab_clh_OilGasandLodgingSegmentMember_E5D0A51364E0A6F56DB732A7158A0FF9_documentation_en-US" xlink:label="lab_clh_OilGasandLodgingSegmentMember_E5D0A51364E0A6F56DB732A7158A0FF9" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Oil, Gas, and Lodging Segment [Member]</link:label>
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    <link:label id="lab_us-gaap_CorporateAndOtherMember_DECDF3B7A157E916B7A332A7158AA37A_verboseLabel_en-US" xlink:label="lab_us-gaap_CorporateAndOtherMember_DECDF3B7A157E916B7A332A7158AA37A" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Corporate Items</link:label>
    <link:label id="lab_us-gaap_CorporateAndOtherMember_DECDF3B7A157E916B7A332A7158AA37A_label_en-US" xlink:label="lab_us-gaap_CorporateAndOtherMember_DECDF3B7A157E916B7A332A7158AA37A" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Corporate and Other [Member]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CorporateAndOtherMember" xlink:label="loc_us-gaap_CorporateAndOtherMember_DECDF3B7A157E916B7A332A7158AA37A" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CorporateAndOtherMember_DECDF3B7A157E916B7A332A7158AA37A" xlink:to="lab_us-gaap_CorporateAndOtherMember_DECDF3B7A157E916B7A332A7158AA37A" xlink:type="arc" />
    <link:label id="lab_us-gaap_StatementLineItems_262763D7E883B8C89B0E32A7158AC53F_verboseLabel_en-US" xlink:label="lab_us-gaap_StatementLineItems_262763D7E883B8C89B0E32A7158AC53F" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Statement [Line Items]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaap_StatementLineItems_262763D7E883B8C89B0E32A7158AC53F" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StatementLineItems_262763D7E883B8C89B0E32A7158AC53F" xlink:to="lab_us-gaap_StatementLineItems_262763D7E883B8C89B0E32A7158AC53F" xlink:type="arc" />
    <link:label id="lab_us-gaap_Revenues_1F7FAF88EF15D46CA2A032A7158A3C64_terseLabel_en-US" xlink:label="lab_us-gaap_Revenues_1F7FAF88EF15D46CA2A032A7158A3C64" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Total revenues</link:label>
    <link:label id="lab_us-gaap_Revenues_1F7FAF88EF15D46CA2A032A7158A3C64_label_en-US" xlink:label="lab_us-gaap_Revenues_1F7FAF88EF15D46CA2A032A7158A3C64" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Revenues</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_Revenues" xlink:label="loc_us-gaap_Revenues_1F7FAF88EF15D46CA2A032A7158A3C64" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_Revenues_1F7FAF88EF15D46CA2A032A7158A3C64" xlink:to="lab_us-gaap_Revenues_1F7FAF88EF15D46CA2A032A7158A3C64" xlink:type="arc" />
    <link:label id="lab_clh_SegmentReportingInformationRevenuePercent_E6409472A35A6DD625C932A7158AE708_terseLabel_en-US" xlink:label="lab_clh_SegmentReportingInformationRevenuePercent_E6409472A35A6DD625C932A7158AE708" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Percent of revenues</link:label>
    <link:label id="lab_clh_SegmentReportingInformationRevenuePercent_E6409472A35A6DD625C932A7158AE708_label_en-US" xlink:label="lab_clh_SegmentReportingInformationRevenuePercent_E6409472A35A6DD625C932A7158AE708" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Segment Reporting Information Revenue Percent</link:label>
    <link:label id="lab_clh_SegmentReportingInformationRevenuePercent_E6409472A35A6DD625C932A7158AE708_documentation_en-US" xlink:label="lab_clh_SegmentReportingInformationRevenuePercent_E6409472A35A6DD625C932A7158AE708" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Segment Reporting Information Revenue Percent</link:label>
    <link:loc xlink:href="clh-20171231.xsd#clh_SegmentReportingInformationRevenuePercent" xlink:label="loc_clh_SegmentReportingInformationRevenuePercent_E6409472A35A6DD625C932A7158AE708" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_clh_SegmentReportingInformationRevenuePercent_E6409472A35A6DD625C932A7158AE708" xlink:to="lab_clh_SegmentReportingInformationRevenuePercent_E6409472A35A6DD625C932A7158AE708" xlink:type="arc" />
    <link:label id="lab_us-gaap_PropertyPlantAndEquipmentNet_DBED37024A7EB40CB8F032A7158A0BF2_terseLabel_en-US" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentNet_DBED37024A7EB40CB8F032A7158A0BF2" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Property, plant and equipment, net</link:label>
    <link:label id="lab_us-gaap_PropertyPlantAndEquipmentNet_DBED37024A7EB40CB8F032A7158A0BF2_label_en-US" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentNet_DBED37024A7EB40CB8F032A7158A0BF2" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Property, Plant and Equipment, Net</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PropertyPlantAndEquipmentNet" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentNet_DBED37024A7EB40CB8F032A7158A0BF2" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentNet_DBED37024A7EB40CB8F032A7158A0BF2" xlink:to="lab_us-gaap_PropertyPlantAndEquipmentNet_DBED37024A7EB40CB8F032A7158A0BF2" xlink:type="arc" />
    <link:label id="lab_clh_PropertyPlantAndEquipmentNetPercent_9CFA5052D4D6B507A43332A7158A7193_terseLabel_en-US" xlink:label="lab_clh_PropertyPlantAndEquipmentNetPercent_9CFA5052D4D6B507A43332A7158A7193" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Percent of property, plant and equipment, net</link:label>
    <link:label id="lab_clh_PropertyPlantAndEquipmentNetPercent_9CFA5052D4D6B507A43332A7158A7193_label_en-US" xlink:label="lab_clh_PropertyPlantAndEquipmentNetPercent_9CFA5052D4D6B507A43332A7158A7193" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Property Plant And Equipment Net Percent</link:label>
    <link:label id="lab_clh_PropertyPlantAndEquipmentNetPercent_9CFA5052D4D6B507A43332A7158A7193_documentation_en-US" xlink:label="lab_clh_PropertyPlantAndEquipmentNetPercent_9CFA5052D4D6B507A43332A7158A7193" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Property Plant And Equipment Net Percent</link:label>
    <link:loc xlink:href="clh-20171231.xsd#clh_PropertyPlantAndEquipmentNetPercent" xlink:label="loc_clh_PropertyPlantAndEquipmentNetPercent_9CFA5052D4D6B507A43332A7158A7193" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_clh_PropertyPlantAndEquipmentNetPercent_9CFA5052D4D6B507A43332A7158A7193" xlink:to="lab_clh_PropertyPlantAndEquipmentNetPercent_9CFA5052D4D6B507A43332A7158A7193" xlink:type="arc" />
    <link:label id="lab_us-gaap_IntangibleAssetsNetExcludingGoodwill_390F5963335592BB736E32A7158AD2A5_terseLabel_en-US" xlink:label="lab_us-gaap_IntangibleAssetsNetExcludingGoodwill_390F5963335592BB736E32A7158AD2A5" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Permits and other intangibles, net</link:label>
    <link:label id="lab_us-gaap_IntangibleAssetsNetExcludingGoodwill_390F5963335592BB736E32A7158AD2A5_label_en-US" xlink:label="lab_us-gaap_IntangibleAssetsNetExcludingGoodwill_390F5963335592BB736E32A7158AD2A5" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Intangible Assets, Net (Excluding Goodwill)</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IntangibleAssetsNetExcludingGoodwill" xlink:label="loc_us-gaap_IntangibleAssetsNetExcludingGoodwill_390F5963335592BB736E32A7158AD2A5" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IntangibleAssetsNetExcludingGoodwill_390F5963335592BB736E32A7158AD2A5" xlink:to="lab_us-gaap_IntangibleAssetsNetExcludingGoodwill_390F5963335592BB736E32A7158AD2A5" xlink:type="arc" />
    <link:label id="lab_clh_IntangibleAssetsNetExcludingGoodwillPercent_5404516A086BB11A4DB332A7158A62EA_terseLabel_en-US" xlink:label="lab_clh_IntangibleAssetsNetExcludingGoodwillPercent_5404516A086BB11A4DB332A7158A62EA" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Percent of permits and other intangibles, net</link:label>
    <link:label id="lab_clh_IntangibleAssetsNetExcludingGoodwillPercent_5404516A086BB11A4DB332A7158A62EA_label_en-US" xlink:label="lab_clh_IntangibleAssetsNetExcludingGoodwillPercent_5404516A086BB11A4DB332A7158A62EA" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Intangible Assets Net Excluding Goodwill Percent</link:label>
    <link:label id="lab_clh_IntangibleAssetsNetExcludingGoodwillPercent_5404516A086BB11A4DB332A7158A62EA_documentation_en-US" xlink:label="lab_clh_IntangibleAssetsNetExcludingGoodwillPercent_5404516A086BB11A4DB332A7158A62EA" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Intangible Assets Net Excluding Goodwill Percent</link:label>
    <link:loc xlink:href="clh-20171231.xsd#clh_IntangibleAssetsNetExcludingGoodwillPercent" xlink:label="loc_clh_IntangibleAssetsNetExcludingGoodwillPercent_5404516A086BB11A4DB332A7158A62EA" xlink:type="locator" />
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    <link:label id="lab_us-gaap_Goodwill_8F260FA9AF88E9B148FC32A7158A17B8_terseLabel_en-US" xlink:label="lab_us-gaap_Goodwill_8F260FA9AF88E9B148FC32A7158A17B8" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Goodwill</link:label>
    <link:label id="lab_us-gaap_Goodwill_8F260FA9AF88E9B148FC32A7158A17B8_label_en-US" xlink:label="lab_us-gaap_Goodwill_8F260FA9AF88E9B148FC32A7158A17B8" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Goodwill</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_Goodwill" xlink:label="loc_us-gaap_Goodwill_8F260FA9AF88E9B148FC32A7158A17B8" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_Goodwill_8F260FA9AF88E9B148FC32A7158A17B8" xlink:to="lab_us-gaap_Goodwill_8F260FA9AF88E9B148FC32A7158A17B8" xlink:type="arc" />
    <link:label id="lab_us-gaap_IntangibleAssetsNetIncludingGoodwill_62A396F84E7ED3BF1F3D32A7158A6331_totalLabel_en-US" xlink:label="lab_us-gaap_IntangibleAssetsNetIncludingGoodwill_62A396F84E7ED3BF1F3D32A7158A6331" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Goodwill and Permits and other intangibles, net</link:label>
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    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IntangibleAssetsNetIncludingGoodwill" xlink:label="loc_us-gaap_IntangibleAssetsNetIncludingGoodwill_62A396F84E7ED3BF1F3D32A7158A6331" xlink:type="locator" />
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    <link:label id="lab_us-gaap_Assets_FE7B3E82050FE245FEB732A7158ACEB0_terseLabel_en-US" xlink:label="lab_us-gaap_Assets_FE7B3E82050FE245FEB732A7158ACEB0" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Assets</link:label>
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    <link:label id="lab_clh_CatalystServicesMember_11295F3BC8632F5FA095D975B59A45FB_terseLabel_en-US" xlink:label="lab_clh_CatalystServicesMember_11295F3BC8632F5FA095D975B59A45FB" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Catalyst Services</link:label>
    <link:label id="lab_clh_CatalystServicesMember_11295F3BC8632F5FA095D975B59A45FB_label_en-US" xlink:label="lab_clh_CatalystServicesMember_11295F3BC8632F5FA095D975B59A45FB" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Catalyst Services [Member]</link:label>
    <link:label id="lab_clh_CatalystServicesMember_11295F3BC8632F5FA095D975B59A45FB_documentation_en-US" xlink:label="lab_clh_CatalystServicesMember_11295F3BC8632F5FA095D975B59A45FB" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Catalyst Services [Member]</link:label>
    <link:loc xlink:href="clh-20171231.xsd#clh_CatalystServicesMember" xlink:label="loc_clh_CatalystServicesMember_11295F3BC8632F5FA095D975B59A45FB" xlink:type="locator" />
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    <link:label id="lab_us-gaap_DisposalGroupClassificationAxis_3C9EB227BAD4B1B78446D975B59B5EDE_terseLabel_en-US" xlink:label="lab_us-gaap_DisposalGroupClassificationAxis_3C9EB227BAD4B1B78446D975B59B5EDE" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Disposal Group Classification [Axis]</link:label>
    <link:label id="lab_us-gaap_DisposalGroupClassificationAxis_3C9EB227BAD4B1B78446D975B59B5EDE_label_en-US" xlink:label="lab_us-gaap_DisposalGroupClassificationAxis_3C9EB227BAD4B1B78446D975B59B5EDE" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Disposal Group Classification [Axis]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DisposalGroupClassificationAxis" xlink:label="loc_us-gaap_DisposalGroupClassificationAxis_3C9EB227BAD4B1B78446D975B59B5EDE" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DisposalGroupClassificationAxis_3C9EB227BAD4B1B78446D975B59B5EDE" xlink:to="lab_us-gaap_DisposalGroupClassificationAxis_3C9EB227BAD4B1B78446D975B59B5EDE" xlink:type="arc" />
    <link:label id="lab_us-gaap_DisposalGroupClassificationDomain_DD265757AECAC650F341D975B59B761D_terseLabel_en-US" xlink:label="lab_us-gaap_DisposalGroupClassificationDomain_DD265757AECAC650F341D975B59B761D" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Disposal Group Classification [Domain]</link:label>
    <link:label id="lab_us-gaap_DisposalGroupClassificationDomain_DD265757AECAC650F341D975B59B761D_label_en-US" xlink:label="lab_us-gaap_DisposalGroupClassificationDomain_DD265757AECAC650F341D975B59B761D" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Disposal Group Classification [Domain]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DisposalGroupClassificationDomain" xlink:label="loc_us-gaap_DisposalGroupClassificationDomain_DD265757AECAC650F341D975B59B761D" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DisposalGroupClassificationDomain_DD265757AECAC650F341D975B59B761D" xlink:to="lab_us-gaap_DisposalGroupClassificationDomain_DD265757AECAC650F341D975B59B761D" xlink:type="arc" />
    <link:label id="lab_us-gaap_DisposalGroupDisposedOfBySaleNotDiscontinuedOperationsMember_2E7F108AAAC2CCFF85D0D975B59B100C_terseLabel_en-US" xlink:label="lab_us-gaap_DisposalGroupDisposedOfBySaleNotDiscontinuedOperationsMember_2E7F108AAAC2CCFF85D0D975B59B100C" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Disposal Group, Disposed of by Sale, Not Discontinued Operations</link:label>
    <link:label id="lab_us-gaap_DisposalGroupDisposedOfBySaleNotDiscontinuedOperationsMember_2E7F108AAAC2CCFF85D0D975B59B100C_label_en-US" xlink:label="lab_us-gaap_DisposalGroupDisposedOfBySaleNotDiscontinuedOperationsMember_2E7F108AAAC2CCFF85D0D975B59B100C" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Disposal Group, Disposed of by Sale, Not Discontinued Operations [Member]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DisposalGroupDisposedOfBySaleNotDiscontinuedOperationsMember" xlink:label="loc_us-gaap_DisposalGroupDisposedOfBySaleNotDiscontinuedOperationsMember_2E7F108AAAC2CCFF85D0D975B59B100C" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DisposalGroupDisposedOfBySaleNotDiscontinuedOperationsMember_2E7F108AAAC2CCFF85D0D975B59B100C" xlink:to="lab_us-gaap_DisposalGroupDisposedOfBySaleNotDiscontinuedOperationsMember_2E7F108AAAC2CCFF85D0D975B59B100C" xlink:type="arc" />
    <link:label id="lab_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_1301D3DFF8A5131E15E0D975B59BE0CC_terseLabel_en-US" xlink:label="lab_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_1301D3DFF8A5131E15E0D975B59BE0CC" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]</link:label>
    <link:label id="lab_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_1301D3DFF8A5131E15E0D975B59BE0CC_label_en-US" xlink:label="lab_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_1301D3DFF8A5131E15E0D975B59BE0CC" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems" xlink:label="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_1301D3DFF8A5131E15E0D975B59BE0CC" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_1301D3DFF8A5131E15E0D975B59BE0CC" xlink:to="lab_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_1301D3DFF8A5131E15E0D975B59BE0CC" xlink:type="arc" />
    <link:label id="lab_us-gaap_AssetsOfDisposalGroupIncludingDiscontinuedOperationCurrent_D3727772FD5380637875D975B59B691F_terseLabel_en-US" xlink:label="lab_us-gaap_AssetsOfDisposalGroupIncludingDiscontinuedOperationCurrent_D3727772FD5380637875D975B59B691F" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Total current assets</link:label>
    <link:label id="lab_us-gaap_AssetsOfDisposalGroupIncludingDiscontinuedOperationCurrent_D3727772FD5380637875D975B59B691F_label_en-US" xlink:label="lab_us-gaap_AssetsOfDisposalGroupIncludingDiscontinuedOperationCurrent_D3727772FD5380637875D975B59B691F" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Disposal Group, Including Discontinued Operation, Assets, Current</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AssetsOfDisposalGroupIncludingDiscontinuedOperationCurrent" xlink:label="loc_us-gaap_AssetsOfDisposalGroupIncludingDiscontinuedOperationCurrent_D3727772FD5380637875D975B59B691F" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AssetsOfDisposalGroupIncludingDiscontinuedOperationCurrent_D3727772FD5380637875D975B59B691F" xlink:to="lab_us-gaap_AssetsOfDisposalGroupIncludingDiscontinuedOperationCurrent_D3727772FD5380637875D975B59B691F" xlink:type="arc" />
    <link:label id="lab_us-gaap_DisposalGroupIncludingDiscontinuedOperationPropertyPlantAndEquipmentNoncurrent_B77751F49A1883ADD193D975B59B0EE8_terseLabel_en-US" xlink:label="lab_us-gaap_DisposalGroupIncludingDiscontinuedOperationPropertyPlantAndEquipmentNoncurrent_B77751F49A1883ADD193D975B59B0EE8" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Property, plant and equipment, net</link:label>
    <link:label id="lab_us-gaap_DisposalGroupIncludingDiscontinuedOperationPropertyPlantAndEquipmentNoncurrent_B77751F49A1883ADD193D975B59B0EE8_label_en-US" xlink:label="lab_us-gaap_DisposalGroupIncludingDiscontinuedOperationPropertyPlantAndEquipmentNoncurrent_B77751F49A1883ADD193D975B59B0EE8" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Disposal Group, Including Discontinued Operation, Property, Plant and Equipment, Noncurrent</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DisposalGroupIncludingDiscontinuedOperationPropertyPlantAndEquipmentNoncurrent" xlink:label="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationPropertyPlantAndEquipmentNoncurrent_B77751F49A1883ADD193D975B59B0EE8" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationPropertyPlantAndEquipmentNoncurrent_B77751F49A1883ADD193D975B59B0EE8" xlink:to="lab_us-gaap_DisposalGroupIncludingDiscontinuedOperationPropertyPlantAndEquipmentNoncurrent_B77751F49A1883ADD193D975B59B0EE8" xlink:type="arc" />
    <link:label id="lab_us-gaap_DisposalGroupIncludingDiscontinuedOperationOtherNoncurrentAssets_A831122D788FF3687775D975B59B4A5F_terseLabel_en-US" xlink:label="lab_us-gaap_DisposalGroupIncludingDiscontinuedOperationOtherNoncurrentAssets_A831122D788FF3687775D975B59B4A5F" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Total other assets</link:label>
    <link:label id="lab_us-gaap_DisposalGroupIncludingDiscontinuedOperationOtherNoncurrentAssets_A831122D788FF3687775D975B59B4A5F_label_en-US" xlink:label="lab_us-gaap_DisposalGroupIncludingDiscontinuedOperationOtherNoncurrentAssets_A831122D788FF3687775D975B59B4A5F" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Disposal Group, Including Discontinued Operation, Other Assets, Noncurrent</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DisposalGroupIncludingDiscontinuedOperationOtherNoncurrentAssets" xlink:label="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationOtherNoncurrentAssets_A831122D788FF3687775D975B59B4A5F" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationOtherNoncurrentAssets_A831122D788FF3687775D975B59B4A5F" xlink:to="lab_us-gaap_DisposalGroupIncludingDiscontinuedOperationOtherNoncurrentAssets_A831122D788FF3687775D975B59B4A5F" xlink:type="arc" />
    <link:label id="lab_us-gaap_AssetsOfDisposalGroupIncludingDiscontinuedOperation_A5BEA5F08B12D54F462AD975B59BB957_totalLabel_en-US" xlink:label="lab_us-gaap_AssetsOfDisposalGroupIncludingDiscontinuedOperation_A5BEA5F08B12D54F462AD975B59BB957" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Total assets divested</link:label>
    <link:label id="lab_us-gaap_AssetsOfDisposalGroupIncludingDiscontinuedOperation_A5BEA5F08B12D54F462AD975B59BB957_label_en-US" xlink:label="lab_us-gaap_AssetsOfDisposalGroupIncludingDiscontinuedOperation_A5BEA5F08B12D54F462AD975B59BB957" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Disposal Group, Including Discontinued Operation, Assets</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AssetsOfDisposalGroupIncludingDiscontinuedOperation" xlink:label="loc_us-gaap_AssetsOfDisposalGroupIncludingDiscontinuedOperation_A5BEA5F08B12D54F462AD975B59BB957" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AssetsOfDisposalGroupIncludingDiscontinuedOperation_A5BEA5F08B12D54F462AD975B59BB957" xlink:to="lab_us-gaap_AssetsOfDisposalGroupIncludingDiscontinuedOperation_A5BEA5F08B12D54F462AD975B59BB957" xlink:type="arc" />
    <link:label id="lab_us-gaap_LiabilitiesOfDisposalGroupIncludingDiscontinuedOperationCurrent_8EEC6EF4F9DA60B7B18CD975B59B98A2_terseLabel_en-US" xlink:label="lab_us-gaap_LiabilitiesOfDisposalGroupIncludingDiscontinuedOperationCurrent_8EEC6EF4F9DA60B7B18CD975B59B98A2" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Total current liabilities</link:label>
    <link:label id="lab_us-gaap_LiabilitiesOfDisposalGroupIncludingDiscontinuedOperationCurrent_8EEC6EF4F9DA60B7B18CD975B59B98A2_label_en-US" xlink:label="lab_us-gaap_LiabilitiesOfDisposalGroupIncludingDiscontinuedOperationCurrent_8EEC6EF4F9DA60B7B18CD975B59B98A2" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Disposal Group, Including Discontinued Operation, Liabilities, Current</link:label>
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    <link:label id="lab_us-gaap_DisposalGroupIncludingDiscontinuedOperationOtherNoncurrentLiabilities_1FA786AD4332796C6F08D975B59B79C1_terseLabel_en-US" xlink:label="lab_us-gaap_DisposalGroupIncludingDiscontinuedOperationOtherNoncurrentLiabilities_1FA786AD4332796C6F08D975B59B79C1" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Total other liabilities</link:label>
    <link:label id="lab_us-gaap_DisposalGroupIncludingDiscontinuedOperationOtherNoncurrentLiabilities_1FA786AD4332796C6F08D975B59B79C1_label_en-US" xlink:label="lab_us-gaap_DisposalGroupIncludingDiscontinuedOperationOtherNoncurrentLiabilities_1FA786AD4332796C6F08D975B59B79C1" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Disposal Group, Including Discontinued Operation, Other Liabilities, Noncurrent</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DisposalGroupIncludingDiscontinuedOperationOtherNoncurrentLiabilities" xlink:label="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationOtherNoncurrentLiabilities_1FA786AD4332796C6F08D975B59B79C1" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationOtherNoncurrentLiabilities_1FA786AD4332796C6F08D975B59B79C1" xlink:to="lab_us-gaap_DisposalGroupIncludingDiscontinuedOperationOtherNoncurrentLiabilities_1FA786AD4332796C6F08D975B59B79C1" xlink:type="arc" />
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    <link:label id="lab_us-gaap_LiabilitiesOfDisposalGroupIncludingDiscontinuedOperation_45AD438CB1543193E376D975B59BE0F9_label_en-US" xlink:label="lab_us-gaap_LiabilitiesOfDisposalGroupIncludingDiscontinuedOperation_45AD438CB1543193E376D975B59BE0F9" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Disposal Group, Including Discontinued Operation, Liabilities</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LiabilitiesOfDisposalGroupIncludingDiscontinuedOperation" xlink:label="loc_us-gaap_LiabilitiesOfDisposalGroupIncludingDiscontinuedOperation_45AD438CB1543193E376D975B59BE0F9" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LiabilitiesOfDisposalGroupIncludingDiscontinuedOperation_45AD438CB1543193E376D975B59BE0F9" xlink:to="lab_us-gaap_LiabilitiesOfDisposalGroupIncludingDiscontinuedOperation_45AD438CB1543193E376D975B59BE0F9" xlink:type="arc" />
    <link:label id="lab_clh_DisposalGroupIncludingDiscontinuedOperationAssetsLiabilitiesNet_8E485F6DDA0144D88B9CD975B59B2DA1_totalLabel_en-US" xlink:label="lab_clh_DisposalGroupIncludingDiscontinuedOperationAssetsLiabilitiesNet_8E485F6DDA0144D88B9CD975B59B2DA1" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Net carrying value divested</link:label>
    <link:label id="lab_clh_DisposalGroupIncludingDiscontinuedOperationAssetsLiabilitiesNet_8E485F6DDA0144D88B9CD975B59B2DA1_label_en-US" xlink:label="lab_clh_DisposalGroupIncludingDiscontinuedOperationAssetsLiabilitiesNet_8E485F6DDA0144D88B9CD975B59B2DA1" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Disposal Group, Including Discontinued Operation, Assets (Liabilities), Net</link:label>
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    <link:label id="lab_us-gaap_AssetsOfDisposalGroupIncludingDiscontinuedOperation_FC296D74364C884C40D072653058264F_terseLabel_en-US" xlink:label="lab_us-gaap_AssetsOfDisposalGroupIncludingDiscontinuedOperation_FC296D74364C884C40D072653058264F" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Total assets divested</link:label>
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    <link:label id="lab_us-gaap_AccrualForEnvironmentalLossContingenciesUndiscountedDueWithinOneYear_27CBDAE36AE11E0FE985DB9E1468E761_terseLabel_en-US" xlink:label="lab_us-gaap_AccrualForEnvironmentalLossContingenciesUndiscountedDueWithinOneYear_27CBDAE36AE11E0FE985DB9E1468E761" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2018</link:label>
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    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AccrualForEnvironmentalLossContingenciesUndiscountedDueWithinOneYear" xlink:label="loc_us-gaap_AccrualForEnvironmentalLossContingenciesUndiscountedDueWithinOneYear_27CBDAE36AE11E0FE985DB9E1468E761" xlink:type="locator" />
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    <link:label id="lab_us-gaap_AccrualForEnvironmentalLossContingenciesUndiscountedDueInSecondYear_B9DADC5C94F73BA12CB4DB9E1468853C_terseLabel_en-US" xlink:label="lab_us-gaap_AccrualForEnvironmentalLossContingenciesUndiscountedDueInSecondYear_B9DADC5C94F73BA12CB4DB9E1468853C" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2019</link:label>
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    <link:label id="lab_us-gaap_AccrualForEnvironmentalLossContingenciesUndiscountedDueInThirdYear_1EFF89802FA5F31CA75CDB9E1468F47A_terseLabel_en-US" xlink:label="lab_us-gaap_AccrualForEnvironmentalLossContingenciesUndiscountedDueInThirdYear_1EFF89802FA5F31CA75CDB9E1468F47A" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2020</link:label>
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    <link:label id="lab_clh_AssetRetirementObligationChangesRecordedInStatementOfIncome_F942C5F870B7D74CA42F7265302C4FB9_documentation_en-US" xlink:label="lab_clh_AssetRetirementObligationChangesRecordedInStatementOfIncome_F942C5F870B7D74CA42F7265302C4FB9" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">The amount of change in the asset retirement obligation, during the current period, for changes in estimates recorded in the statement of income.</link:label>
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    <link:label id="lab_clh_AssetRetirementObligationChangesRecordedinBalanceSheet_88CF02C304700602C78B7265302C103D_documentation_en-US" xlink:label="lab_clh_AssetRetirementObligationChangesRecordedinBalanceSheet_88CF02C304700602C78B7265302C103D" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the amount of change in the asset retirement obligation, during the current period for other changes in estimates recorded in the balance sheet.</link:label>
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    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncomeLossFromContinuingOperationsPerBasicShare" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsPerBasicShare_DA2F4E6F6EDC9B78C69939D28385D4C2" xlink:type="locator" />
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    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncomeLossFromContinuingOperationsPerDilutedShare" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsPerDilutedShare_B5BC9A2D1AF34AC88DD739D2838585E2" xlink:type="locator" />
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    <link:loc xlink:href="clh-20171231.xsd#clh_LeaseTermsRangeMaximum" xlink:label="loc_clh_LeaseTermsRangeMaximum_D0DC63C83E2F2F3734DA72652F93D1B9" xlink:type="locator" />
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    <link:label id="lab_us-gaap_OperatingLeasesFutureMinimumPaymentsDueCurrent_35E71D8227605F2CE47072652F93F042_terseLabel_en-US" xlink:label="lab_us-gaap_OperatingLeasesFutureMinimumPaymentsDueCurrent_35E71D8227605F2CE47072652F93F042" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2018</link:label>
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    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OperatingLeasesFutureMinimumPaymentsDueCurrent" xlink:label="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsDueCurrent_35E71D8227605F2CE47072652F93F042" xlink:type="locator" />
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    <link:label id="lab_us-gaap_OperatingLeasesFutureMinimumPaymentsDueInTwoYears_211364A19EEE52C6F1C572652F934B6B_terseLabel_en-US" xlink:label="lab_us-gaap_OperatingLeasesFutureMinimumPaymentsDueInTwoYears_211364A19EEE52C6F1C572652F934B6B" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2019</link:label>
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    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OperatingLeasesFutureMinimumPaymentsDueInTwoYears" xlink:label="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsDueInTwoYears_211364A19EEE52C6F1C572652F934B6B" xlink:type="locator" />
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    <link:label id="lab_us-gaap_OperatingLeasesFutureMinimumPaymentsDueInThreeYears_B9CBCAAAE7C8B478F3F172652F934270_terseLabel_en-US" xlink:label="lab_us-gaap_OperatingLeasesFutureMinimumPaymentsDueInThreeYears_B9CBCAAAE7C8B478F3F172652F934270" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2020</link:label>
    <link:label id="lab_us-gaap_OperatingLeasesFutureMinimumPaymentsDueInThreeYears_B9CBCAAAE7C8B478F3F172652F934270_label_en-US" xlink:label="lab_us-gaap_OperatingLeasesFutureMinimumPaymentsDueInThreeYears_B9CBCAAAE7C8B478F3F172652F934270" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Operating Leases, Future Minimum Payments, Due in Three Years</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OperatingLeasesFutureMinimumPaymentsDueInThreeYears" xlink:label="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsDueInThreeYears_B9CBCAAAE7C8B478F3F172652F934270" xlink:type="locator" />
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    <link:label id="lab_us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFourYears_CDB02DEFB6165F2A175272652F93C50F_terseLabel_en-US" xlink:label="lab_us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFourYears_CDB02DEFB6165F2A175272652F93C50F" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2021</link:label>
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    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFourYears" xlink:label="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFourYears_CDB02DEFB6165F2A175272652F93C50F" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFourYears_CDB02DEFB6165F2A175272652F93C50F" xlink:to="lab_us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFourYears_CDB02DEFB6165F2A175272652F93C50F" xlink:type="arc" />
    <link:label id="lab_us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFiveYears_64F5EEEBBEEA8E76FEF272652F933615_terseLabel_en-US" xlink:label="lab_us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFiveYears_64F5EEEBBEEA8E76FEF272652F933615" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2022</link:label>
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    <link:label id="lab_us-gaap_TaxesPayableCurrent_059261BE4DF9EAB5B1E6BD703AB3CE58_terseLabel_en-US" xlink:label="lab_us-gaap_TaxesPayableCurrent_059261BE4DF9EAB5B1E6BD703AB3CE58" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Income, real estate, sales and other taxes</link:label>
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    <link:label id="lab_us-gaap_OtherAccruedLiabilitiesCurrent_CE0487E62FC07EFE57A4BD703AB3439D_terseLabel_en-US" xlink:label="lab_us-gaap_OtherAccruedLiabilitiesCurrent_CE0487E62FC07EFE57A4BD703AB3439D" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Other</link:label>
    <link:label id="lab_us-gaap_OtherAccruedLiabilitiesCurrent_CE0487E62FC07EFE57A4BD703AB3439D_label_en-US" xlink:label="lab_us-gaap_OtherAccruedLiabilitiesCurrent_CE0487E62FC07EFE57A4BD703AB3439D" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Other Accrued Liabilities, Current</link:label>
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    <link:label id="lab_us-gaap_AccruedLiabilitiesCurrent_2CD383325A79A7BC8A78BD703AB3FDCC_totalLabel_en-US" xlink:label="lab_us-gaap_AccruedLiabilitiesCurrent_2CD383325A79A7BC8A78BD703AB3FDCC" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Total accrued expenses</link:label>
    <link:label id="lab_us-gaap_AccruedLiabilitiesCurrent_2CD383325A79A7BC8A78BD703AB3FDCC_label_en-US" xlink:label="lab_us-gaap_AccruedLiabilitiesCurrent_2CD383325A79A7BC8A78BD703AB3FDCC" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Accrued Liabilities, Current</link:label>
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    <link:label id="lab_us-gaap_LitigationReserveCurrent_AB4200669C323E68838FBD703AB306B9_terseLabel_en-US" xlink:label="lab_us-gaap_LitigationReserveCurrent_AB4200669C323E68838FBD703AB306B9" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Accrued legal matters</link:label>
    <link:label id="lab_us-gaap_LitigationReserveCurrent_AB4200669C323E68838FBD703AB306B9_label_en-US" xlink:label="lab_us-gaap_LitigationReserveCurrent_AB4200669C323E68838FBD703AB306B9" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Estimated Litigation Liability, Current</link:label>
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    <link:label id="lab_us-gaap_SupplementalUnemploymentBenefitsSeveranceBenefits_69C28AB690A758A96B6DBD703AB33D99_terseLabel_en-US" xlink:label="lab_us-gaap_SupplementalUnemploymentBenefitsSeveranceBenefits_69C28AB690A758A96B6DBD703AB33D99" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Accrued severance charges</link:label>
    <link:label id="lab_us-gaap_SupplementalUnemploymentBenefitsSeveranceBenefits_69C28AB690A758A96B6DBD703AB33D99_label_en-US" xlink:label="lab_us-gaap_SupplementalUnemploymentBenefitsSeveranceBenefits_69C28AB690A758A96B6DBD703AB33D99" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Supplemental Unemployment Benefits, Severance Benefits</link:label>
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    <link:label id="lab_us-gaap_IncomeStatementAbstract_47F6B1C178429D08186C32A71649D5F6_label_en-US" xlink:label="lab_us-gaap_IncomeStatementAbstract_47F6B1C178429D08186C32A71649D5F6" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Income Statement [Abstract]</link:label>
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    <link:label id="lab_us-gaap_InterestIncomeOperating_BDF161FCAA081F7262CC32A7164900F4_label_en-US" xlink:label="lab_us-gaap_InterestIncomeOperating_BDF161FCAA081F7262CC32A7164900F4" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Interest Income, Operating</link:label>
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    <link:label id="lab_clh_PrivatelyHeldWashingMachineCompanyMember_3F3CBC8CAA3638D7480CBF064EB65864_terseLabel_en-US" xlink:label="lab_clh_PrivatelyHeldWashingMachineCompanyMember_3F3CBC8CAA3638D7480CBF064EB65864" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Privately Held Washing Machine Company</link:label>
    <link:label id="lab_clh_PrivatelyHeldWashingMachineCompanyMember_3F3CBC8CAA3638D7480CBF064EB65864_label_en-US" xlink:label="lab_clh_PrivatelyHeldWashingMachineCompanyMember_3F3CBC8CAA3638D7480CBF064EB65864" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Privately Held Washing Machine Company [Member]</link:label>
    <link:label id="lab_clh_PrivatelyHeldWashingMachineCompanyMember_3F3CBC8CAA3638D7480CBF064EB65864_documentation_en-US" xlink:label="lab_clh_PrivatelyHeldWashingMachineCompanyMember_3F3CBC8CAA3638D7480CBF064EB65864" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Privately Held Washing Machine Company [Member]</link:label>
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    <link:label id="lab_clh_LonestarMember_4169B2A96650E76C98C5BF064EB680C5_terseLabel_en-US" xlink:label="lab_clh_LonestarMember_4169B2A96650E76C98C5BF064EB680C5" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Lonestar</link:label>
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    <link:label id="lab_clh_LonestarMember_4169B2A96650E76C98C5BF064EB680C5_documentation_en-US" xlink:label="lab_clh_LonestarMember_4169B2A96650E76C98C5BF064EB680C5" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Lonestar [Member]</link:label>
    <link:loc xlink:href="clh-20171231.xsd#clh_LonestarMember" xlink:label="loc_clh_LonestarMember_4169B2A96650E76C98C5BF064EB680C5" xlink:type="locator" />
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    <link:label id="lab_clh_A2017AcquisitionsMember_5334FBF7DE7FB344F46BBF064EB6CC40_terseLabel_en-US" xlink:label="lab_clh_A2017AcquisitionsMember_5334FBF7DE7FB344F46BBF064EB6CC40" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2017 Acquisitions</link:label>
    <link:label id="lab_clh_A2017AcquisitionsMember_5334FBF7DE7FB344F46BBF064EB6CC40_label_en-US" xlink:label="lab_clh_A2017AcquisitionsMember_5334FBF7DE7FB344F46BBF064EB6CC40" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">2017 Acquisitions [Member]</link:label>
    <link:label id="lab_clh_A2017AcquisitionsMember_5334FBF7DE7FB344F46BBF064EB6CC40_documentation_en-US" xlink:label="lab_clh_A2017AcquisitionsMember_5334FBF7DE7FB344F46BBF064EB6CC40" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">2017 Acquisitions [Member]</link:label>
    <link:loc xlink:href="clh-20171231.xsd#clh_A2017AcquisitionsMember" xlink:label="loc_clh_A2017AcquisitionsMember_5334FBF7DE7FB344F46BBF064EB6CC40" xlink:type="locator" />
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    <link:label id="lab_us-gaap_GoodwillAcquiredDuringPeriod_A59A519E556EBF25B72BBF064EB6C3F9_verboseLabel_en-US" xlink:label="lab_us-gaap_GoodwillAcquiredDuringPeriod_A59A519E556EBF25B72BBF064EB6C3F9" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Goodwill amount</link:label>
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    <link:label id="lab_us-gaap_PaymentsToAcquireBusinessesGross_C3F7C151FF0F72D868F2BF064EB62A3F_verboseLabel_en-US" xlink:label="lab_us-gaap_PaymentsToAcquireBusinessesGross_C3F7C151FF0F72D868F2BF064EB62A3F" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Payments to acquire businesses</link:label>
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    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CostOfGoodsSold_EFE1084D8F8F86B65E56BF064D89BA87" xlink:to="lab_us-gaap_CostOfGoodsSold_EFE1084D8F8F86B65E56BF064D89BA87" xlink:type="arc" />
    <link:label id="lab_us-gaap_CostOfRevenue_4E017DE629C369CF3421BF064D89804C_totalLabel_en-US" xlink:label="lab_us-gaap_CostOfRevenue_4E017DE629C369CF3421BF064D89804C" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Total cost of revenues</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CostOfRevenue" xlink:label="loc_us-gaap_CostOfRevenue_4E017DE629C369CF3421BF064D89804C" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CostOfRevenue_4E017DE629C369CF3421BF064D89804C" xlink:to="lab_us-gaap_CostOfRevenue_4E017DE629C369CF3421BF064D89804C" xlink:type="arc" />
    <link:label id="lab_us-gaap_SellingGeneralAndAdministrativeExpense_80404F43642B262B52FCBF064D898756_terseLabel_en-US" xlink:label="lab_us-gaap_SellingGeneralAndAdministrativeExpense_80404F43642B262B52FCBF064D898756" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Selling, general and administrative expenses</link:label>
    <link:label id="lab_us-gaap_SellingGeneralAndAdministrativeExpense_80404F43642B262B52FCBF064D898756_label_en-US" xlink:label="lab_us-gaap_SellingGeneralAndAdministrativeExpense_80404F43642B262B52FCBF064D898756" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Selling, General and Administrative Expense</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SellingGeneralAndAdministrativeExpense" xlink:label="loc_us-gaap_SellingGeneralAndAdministrativeExpense_80404F43642B262B52FCBF064D898756" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SellingGeneralAndAdministrativeExpense_80404F43642B262B52FCBF064D898756" xlink:to="lab_us-gaap_SellingGeneralAndAdministrativeExpense_80404F43642B262B52FCBF064D898756" xlink:type="arc" />
    <link:label id="lab_clh_AccretionOfEnvironmentalLiabilities_5D1E4F6A4D9905210D77BF064D895CC4_terseLabel_en-US" xlink:label="lab_clh_AccretionOfEnvironmentalLiabilities_5D1E4F6A4D9905210D77BF064D895CC4" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Accretion of environmental liabilities</link:label>
    <link:label id="lab_clh_AccretionOfEnvironmentalLiabilities_5D1E4F6A4D9905210D77BF064D895CC4_label_en-US" xlink:label="lab_clh_AccretionOfEnvironmentalLiabilities_5D1E4F6A4D9905210D77BF064D895CC4" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Accretion of Environmental Liabilities</link:label>
    <link:label id="lab_clh_AccretionOfEnvironmentalLiabilities_5D1E4F6A4D9905210D77BF064D895CC4_documentation_en-US" xlink:label="lab_clh_AccretionOfEnvironmentalLiabilities_5D1E4F6A4D9905210D77BF064D895CC4" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">This element includes accretion expenditure that pertains to asset retirement obligations and environmental remediation.</link:label>
    <link:loc xlink:href="clh-20171231.xsd#clh_AccretionOfEnvironmentalLiabilities" xlink:label="loc_clh_AccretionOfEnvironmentalLiabilities_5D1E4F6A4D9905210D77BF064D895CC4" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_clh_AccretionOfEnvironmentalLiabilities_5D1E4F6A4D9905210D77BF064D895CC4" xlink:to="lab_clh_AccretionOfEnvironmentalLiabilities_5D1E4F6A4D9905210D77BF064D895CC4" xlink:type="arc" />
    <link:label id="lab_us-gaap_DepreciationDepletionAndAmortization_7D83BFB0BB3DEB699967BF064D89DFDE_terseLabel_en-US" xlink:label="lab_us-gaap_DepreciationDepletionAndAmortization_7D83BFB0BB3DEB699967BF064D89DFDE" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Depreciation and amortization</link:label>
    <link:label id="lab_us-gaap_DepreciationDepletionAndAmortization_7D83BFB0BB3DEB699967BF064D89DFDE_label_en-US" xlink:label="lab_us-gaap_DepreciationDepletionAndAmortization_7D83BFB0BB3DEB699967BF064D89DFDE" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Depreciation, Depletion and Amortization</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DepreciationDepletionAndAmortization" xlink:label="loc_us-gaap_DepreciationDepletionAndAmortization_7D83BFB0BB3DEB699967BF064D89DFDE" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DepreciationDepletionAndAmortization_7D83BFB0BB3DEB699967BF064D89DFDE" xlink:to="lab_us-gaap_DepreciationDepletionAndAmortization_7D83BFB0BB3DEB699967BF064D89DFDE" xlink:type="arc" />
    <link:label id="lab_us-gaap_GoodwillImpairmentLoss_A16A40798D8CC98E59C7BF064D894C10_terseLabel_en-US" xlink:label="lab_us-gaap_GoodwillImpairmentLoss_A16A40798D8CC98E59C7BF064D894C10" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Goodwill impairment charges</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_GoodwillImpairmentLoss" xlink:label="loc_us-gaap_GoodwillImpairmentLoss_A16A40798D8CC98E59C7BF064D894C10" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_GoodwillImpairmentLoss_A16A40798D8CC98E59C7BF064D894C10" xlink:to="lab_us-gaap_GoodwillImpairmentLoss_A16A40798D8CC98E59C7BF064D894C10" xlink:type="arc" />
    <link:label id="lab_us-gaap_OperatingIncomeLoss_025F06D4870AC9F2B099BF064D898B4F_totalLabel_en-US" xlink:label="lab_us-gaap_OperatingIncomeLoss_025F06D4870AC9F2B099BF064D898B4F" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Income (loss) from operations</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OperatingIncomeLoss" xlink:label="loc_us-gaap_OperatingIncomeLoss_025F06D4870AC9F2B099BF064D898B4F" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OperatingIncomeLoss_025F06D4870AC9F2B099BF064D898B4F" xlink:to="lab_us-gaap_OperatingIncomeLoss_025F06D4870AC9F2B099BF064D898B4F" xlink:type="arc" />
    <link:label id="lab_us-gaap_GainsLossesOnExtinguishmentOfDebt_628ADC15EE68B85F7C74BF064D891A80_terseLabel_en-US" xlink:label="lab_us-gaap_GainsLossesOnExtinguishmentOfDebt_628ADC15EE68B85F7C74BF064D891A80" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Loss on early extinguishment of debt</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_GainsLossesOnExtinguishmentOfDebt" xlink:label="loc_us-gaap_GainsLossesOnExtinguishmentOfDebt_628ADC15EE68B85F7C74BF064D891A80" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_GainsLossesOnExtinguishmentOfDebt_628ADC15EE68B85F7C74BF064D891A80" xlink:to="lab_us-gaap_GainsLossesOnExtinguishmentOfDebt_628ADC15EE68B85F7C74BF064D891A80" xlink:type="arc" />
    <link:label id="lab_clh_InterestExpenseNet_A2C9A58C86EB4CC8287EBF064D894266_negatedTerseLabel_en-US" xlink:label="lab_clh_InterestExpenseNet_A2C9A58C86EB4CC8287EBF064D894266" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Interest (expense) income, net</link:label>
    <link:label id="lab_clh_InterestExpenseNet_A2C9A58C86EB4CC8287EBF064D894266_label_en-US" xlink:label="lab_clh_InterestExpenseNet_A2C9A58C86EB4CC8287EBF064D894266" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Interest Expense, Net</link:label>
    <link:label id="lab_clh_InterestExpenseNet_A2C9A58C86EB4CC8287EBF064D894266_documentation_en-US" xlink:label="lab_clh_InterestExpenseNet_A2C9A58C86EB4CC8287EBF064D894266" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">This element represents the amount of interest expense, net of investment interest income.</link:label>
    <link:loc xlink:href="clh-20171231.xsd#clh_InterestExpenseNet" xlink:label="loc_clh_InterestExpenseNet_A2C9A58C86EB4CC8287EBF064D894266" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_clh_InterestExpenseNet_A2C9A58C86EB4CC8287EBF064D894266" xlink:to="lab_clh_InterestExpenseNet_A2C9A58C86EB4CC8287EBF064D894266" xlink:type="arc" />
    <link:label id="lab_clh_IncomeLossFromAffiliatesSubsidiariesAndHoldingCompany_A32DD1C74FC06B04825ABF064D894091_terseLabel_en-US" xlink:label="lab_clh_IncomeLossFromAffiliatesSubsidiariesAndHoldingCompany_A32DD1C74FC06B04825ABF064D894091" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Equity in earnings of subsidiaries, net of tax</link:label>
    <link:label id="lab_clh_IncomeLossFromAffiliatesSubsidiariesAndHoldingCompany_A32DD1C74FC06B04825ABF064D894091_label_en-US" xlink:label="lab_clh_IncomeLossFromAffiliatesSubsidiariesAndHoldingCompany_A32DD1C74FC06B04825ABF064D894091" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Income (Loss) from Affiliates Subsidiaries and Holding Company</link:label>
    <link:label id="lab_clh_IncomeLossFromAffiliatesSubsidiariesAndHoldingCompany_A32DD1C74FC06B04825ABF064D894091_documentation_en-US" xlink:label="lab_clh_IncomeLossFromAffiliatesSubsidiariesAndHoldingCompany_A32DD1C74FC06B04825ABF064D894091" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the income (loss) from affiliates, subsidiaries and the holding company.</link:label>
    <link:loc xlink:href="clh-20171231.xsd#clh_IncomeLossFromAffiliatesSubsidiariesAndHoldingCompany" xlink:label="loc_clh_IncomeLossFromAffiliatesSubsidiariesAndHoldingCompany_A32DD1C74FC06B04825ABF064D894091" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_clh_IncomeLossFromAffiliatesSubsidiariesAndHoldingCompany_A32DD1C74FC06B04825ABF064D894091" xlink:to="lab_clh_IncomeLossFromAffiliatesSubsidiariesAndHoldingCompany_A32DD1C74FC06B04825ABF064D894091" xlink:type="arc" />
    <link:label id="lab_clh_NetInterestIncomeFromAffiliatesSubsidiariesAndHoldingCompany_F0289C943A0401D6CD33BF064D89FCCD_terseLabel_en-US" xlink:label="lab_clh_NetInterestIncomeFromAffiliatesSubsidiariesAndHoldingCompany_F0289C943A0401D6CD33BF064D89FCCD" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Intercompany interest income (expense)</link:label>
    <link:label id="lab_clh_NetInterestIncomeFromAffiliatesSubsidiariesAndHoldingCompany_F0289C943A0401D6CD33BF064D89FCCD_label_en-US" xlink:label="lab_clh_NetInterestIncomeFromAffiliatesSubsidiariesAndHoldingCompany_F0289C943A0401D6CD33BF064D89FCCD" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Net Interest Income from Affiliates Subsidiaries and Holding Company</link:label>
    <link:label id="lab_clh_NetInterestIncomeFromAffiliatesSubsidiariesAndHoldingCompany_F0289C943A0401D6CD33BF064D89FCCD_documentation_en-US" xlink:label="lab_clh_NetInterestIncomeFromAffiliatesSubsidiariesAndHoldingCompany_F0289C943A0401D6CD33BF064D89FCCD" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the net interest income from affiliates, subsidiaries and the holding company.</link:label>
    <link:loc xlink:href="clh-20171231.xsd#clh_NetInterestIncomeFromAffiliatesSubsidiariesAndHoldingCompany" xlink:label="loc_clh_NetInterestIncomeFromAffiliatesSubsidiariesAndHoldingCompany_F0289C943A0401D6CD33BF064D89FCCD" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_clh_NetInterestIncomeFromAffiliatesSubsidiariesAndHoldingCompany_F0289C943A0401D6CD33BF064D89FCCD" xlink:to="lab_clh_NetInterestIncomeFromAffiliatesSubsidiariesAndHoldingCompany_F0289C943A0401D6CD33BF064D89FCCD" xlink:type="arc" />
    <link:label id="lab_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments_4506114C481ACEC50880BF064D89D655_totalLabel_en-US" xlink:label="lab_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments_4506114C481ACEC50880BF064D89D655" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Income (loss) before (benefit) provision for income taxes</link:label>
    <link:label id="lab_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments_4506114C481ACEC50880BF064D89D655_label_en-US" xlink:label="lab_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments_4506114C481ACEC50880BF064D89D655" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments_4506114C481ACEC50880BF064D89D655" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments_4506114C481ACEC50880BF064D89D655" xlink:to="lab_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments_4506114C481ACEC50880BF064D89D655" xlink:type="arc" />
    <link:label id="lab_us-gaap_IncomeTaxExpenseBenefit_B6F8BE71723289EE563EBF064D8AC1D8_verboseLabel_en-US" xlink:label="lab_us-gaap_IncomeTaxExpenseBenefit_B6F8BE71723289EE563EBF064D8AC1D8" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">(Benefit) provision for income taxes</link:label>
    <link:label id="lab_us-gaap_IncomeTaxExpenseBenefit_B6F8BE71723289EE563EBF064D8AC1D8_label_en-US" xlink:label="lab_us-gaap_IncomeTaxExpenseBenefit_B6F8BE71723289EE563EBF064D8AC1D8" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Income Tax Expense (Benefit)</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncomeTaxExpenseBenefit" xlink:label="loc_us-gaap_IncomeTaxExpenseBenefit_B6F8BE71723289EE563EBF064D8AC1D8" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncomeTaxExpenseBenefit_B6F8BE71723289EE563EBF064D8AC1D8" xlink:to="lab_us-gaap_IncomeTaxExpenseBenefit_B6F8BE71723289EE563EBF064D8AC1D8" xlink:type="arc" />
    <link:label id="lab_us-gaap_ProfitLoss_EAD96DFCA150CAF1B55DBF064D8AC2D7_totalLabel_en-US" xlink:label="lab_us-gaap_ProfitLoss_EAD96DFCA150CAF1B55DBF064D8AC2D7" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Net income (loss)</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ProfitLoss" xlink:label="loc_us-gaap_ProfitLoss_EAD96DFCA150CAF1B55DBF064D8AC2D7" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ProfitLoss_EAD96DFCA150CAF1B55DBF064D8AC2D7" xlink:to="lab_us-gaap_ProfitLoss_EAD96DFCA150CAF1B55DBF064D8AC2D7" xlink:type="arc" />
    <link:label id="lab_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_3F7DD82FAC4DE0B90ADBBF064D8AABCB_terseLabel_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_3F7DD82FAC4DE0B90ADBBF064D8AABCB" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Other comprehensive income</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_3F7DD82FAC4DE0B90ADBBF064D8AABCB" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_3F7DD82FAC4DE0B90ADBBF064D8AABCB" xlink:to="lab_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_3F7DD82FAC4DE0B90ADBBF064D8AABCB" xlink:type="arc" />
    <link:label id="lab_us-gaap_IncomeLossFromIndividuallySignificantComponentDisposedOfOrHeldForSaleExcludingDiscontinuedOperationsAttributableToParentBeforeIncomeTax_C3D0BF98EBF0E58B298B726530536216_terseLabel_en-US" xlink:label="lab_us-gaap_IncomeLossFromIndividuallySignificantComponentDisposedOfOrHeldForSaleExcludingDiscontinuedOperationsAttributableToParentBeforeIncomeTax_C3D0BF98EBF0E58B298B726530536216" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Income before (benefit) provision for income taxes</link:label>
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    <link:label id="lab_us-gaap_SubsegmentsDomain_B304F2FC8F2471BDD7D5BF064E61A9ED_terseLabel_en-US" xlink:label="lab_us-gaap_SubsegmentsDomain_B304F2FC8F2471BDD7D5BF064E61A9ED" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Subsegments [Domain]</link:label>
    <link:label id="lab_us-gaap_SubsegmentsDomain_B304F2FC8F2471BDD7D5BF064E61A9ED_label_en-US" xlink:label="lab_us-gaap_SubsegmentsDomain_B304F2FC8F2471BDD7D5BF064E61A9ED" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Subsegments [Domain]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SubsegmentsDomain" xlink:label="loc_us-gaap_SubsegmentsDomain_B304F2FC8F2471BDD7D5BF064E61A9ED" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SubsegmentsDomain_B304F2FC8F2471BDD7D5BF064E61A9ED" xlink:to="lab_us-gaap_SubsegmentsDomain_B304F2FC8F2471BDD7D5BF064E61A9ED" xlink:type="arc" />
    <link:label id="lab_clh_LodgingSegmentMember_65FEBC4399843E47DD67BF064E61B7A3_verboseLabel_en-US" xlink:label="lab_clh_LodgingSegmentMember_65FEBC4399843E47DD67BF064E61B7A3" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Lodging Segment</link:label>
    <link:label id="lab_clh_LodgingSegmentMember_65FEBC4399843E47DD67BF064E61B7A3_label_en-US" xlink:label="lab_clh_LodgingSegmentMember_65FEBC4399843E47DD67BF064E61B7A3" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Lodging Segment [Member]</link:label>
    <link:label id="lab_clh_LodgingSegmentMember_65FEBC4399843E47DD67BF064E61B7A3_documentation_en-US" xlink:label="lab_clh_LodgingSegmentMember_65FEBC4399843E47DD67BF064E61B7A3" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Lodging Segment [Member]</link:label>
    <link:loc xlink:href="clh-20171231.xsd#clh_LodgingSegmentMember" xlink:label="loc_clh_LodgingSegmentMember_65FEBC4399843E47DD67BF064E61B7A3" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_clh_LodgingSegmentMember_65FEBC4399843E47DD67BF064E61B7A3" xlink:to="lab_clh_LodgingSegmentMember_65FEBC4399843E47DD67BF064E61B7A3" xlink:type="arc" />
    <link:label id="lab_clh_OilAndGasFieldServicesMember_06CBC02A9B0AA5804994BF064E61B17B_verboseLabel_en-US" xlink:label="lab_clh_OilAndGasFieldServicesMember_06CBC02A9B0AA5804994BF064E61B17B" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Oil and Gas Field Services</link:label>
    <link:label id="lab_clh_OilAndGasFieldServicesMember_06CBC02A9B0AA5804994BF064E61B17B_label_en-US" xlink:label="lab_clh_OilAndGasFieldServicesMember_06CBC02A9B0AA5804994BF064E61B17B" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Oil and Gas Field Services [Member]</link:label>
    <link:label id="lab_clh_OilAndGasFieldServicesMember_06CBC02A9B0AA5804994BF064E61B17B_documentation_en-US" xlink:label="lab_clh_OilAndGasFieldServicesMember_06CBC02A9B0AA5804994BF064E61B17B" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">This element represents the Oil and Gas Field Services segment of the entity.</link:label>
    <link:loc xlink:href="clh-20171231.xsd#clh_OilAndGasFieldServicesMember" xlink:label="loc_clh_OilAndGasFieldServicesMember_06CBC02A9B0AA5804994BF064E61B17B" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_clh_OilAndGasFieldServicesMember_06CBC02A9B0AA5804994BF064E61B17B" xlink:to="lab_clh_OilAndGasFieldServicesMember_06CBC02A9B0AA5804994BF064E61B17B" xlink:type="arc" />
    <link:label id="lab_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassLineItems_5758D5A03E3827A8F08DBF064E61FA14_terseLabel_en-US" xlink:label="lab_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassLineItems_5758D5A03E3827A8F08DBF064E61FA14" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Indefinite-lived Intangible Assets [Line Items]</link:label>
    <link:label id="lab_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassLineItems_5758D5A03E3827A8F08DBF064E61FA14_label_en-US" xlink:label="lab_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassLineItems_5758D5A03E3827A8F08DBF064E61FA14" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Indefinite-lived Intangible Assets [Line Items]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassLineItems" xlink:label="loc_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassLineItems_5758D5A03E3827A8F08DBF064E61FA14" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassLineItems_5758D5A03E3827A8F08DBF064E61FA14" xlink:to="lab_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassLineItems_5758D5A03E3827A8F08DBF064E61FA14" xlink:type="arc" />
    <link:label id="lab_us-gaap_GoodwillImpairedAccumulatedImpairmentLoss_AA1FAC67BB8264657CCBBF064E612740_terseLabel_en-US" xlink:label="lab_us-gaap_GoodwillImpairedAccumulatedImpairmentLoss_AA1FAC67BB8264657CCBBF064E612740" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Accumulated goodwill impairment charges</link:label>
    <link:label id="lab_us-gaap_GoodwillImpairedAccumulatedImpairmentLoss_AA1FAC67BB8264657CCBBF064E612740_label_en-US" xlink:label="lab_us-gaap_GoodwillImpairedAccumulatedImpairmentLoss_AA1FAC67BB8264657CCBBF064E612740" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Goodwill, Impaired, Accumulated Impairment Loss</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_GoodwillImpairedAccumulatedImpairmentLoss" xlink:label="loc_us-gaap_GoodwillImpairedAccumulatedImpairmentLoss_AA1FAC67BB8264657CCBBF064E612740" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_GoodwillImpairedAccumulatedImpairmentLoss_AA1FAC67BB8264657CCBBF064E612740" xlink:to="lab_us-gaap_GoodwillImpairedAccumulatedImpairmentLoss_AA1FAC67BB8264657CCBBF064E612740" xlink:type="arc" />
    <link:label id="lab_us-gaap_GoodwillGross_2B6514BE6C21BD4AE2E2BF064E61DE83_terseLabel_en-US" xlink:label="lab_us-gaap_GoodwillGross_2B6514BE6C21BD4AE2E2BF064E61DE83" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Goodwill</link:label>
    <link:label id="lab_us-gaap_GoodwillGross_2B6514BE6C21BD4AE2E2BF064E61DE83_label_en-US" xlink:label="lab_us-gaap_GoodwillGross_2B6514BE6C21BD4AE2E2BF064E61DE83" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Goodwill, Gross</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_GoodwillGross" xlink:label="loc_us-gaap_GoodwillGross_2B6514BE6C21BD4AE2E2BF064E61DE83" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_GoodwillGross_2B6514BE6C21BD4AE2E2BF064E61DE83" xlink:to="lab_us-gaap_GoodwillGross_2B6514BE6C21BD4AE2E2BF064E61DE83" xlink:type="arc" />
    <link:label id="lab_us-gaap_GoodwillFairValueDisclosure_9937A79BEF113DEEA454BF064E61A62D_terseLabel_en-US" xlink:label="lab_us-gaap_GoodwillFairValueDisclosure_9937A79BEF113DEEA454BF064E61A62D" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Fair value of goodwill</link:label>
    <link:label id="lab_us-gaap_GoodwillFairValueDisclosure_9937A79BEF113DEEA454BF064E61A62D_label_en-US" xlink:label="lab_us-gaap_GoodwillFairValueDisclosure_9937A79BEF113DEEA454BF064E61A62D" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Goodwill, Fair Value Disclosure</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_GoodwillFairValueDisclosure" xlink:label="loc_us-gaap_GoodwillFairValueDisclosure_9937A79BEF113DEEA454BF064E61A62D" xlink:type="locator" />
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    <link:label id="lab_us-gaap_IntangibleAssetsNetExcludingGoodwill_DAF302AB5AA101072A28BF064E62726D_verboseLabel_en-US" xlink:label="lab_us-gaap_IntangibleAssetsNetExcludingGoodwill_DAF302AB5AA101072A28BF064E62726D" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Intangible assets</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IntangibleAssetsNetExcludingGoodwill" xlink:label="loc_us-gaap_IntangibleAssetsNetExcludingGoodwill_DAF302AB5AA101072A28BF064E62726D" xlink:type="locator" />
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    <link:label id="lab_us-gaap_AmortizationOfIntangibleAssets_18F6641C3700F1067779BF064E6200FD_terseLabel_en-US" xlink:label="lab_us-gaap_AmortizationOfIntangibleAssets_18F6641C3700F1067779BF064E6200FD" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Amortization expense of permits and other intangible assets</link:label>
    <link:label id="lab_us-gaap_AmortizationOfIntangibleAssets_18F6641C3700F1067779BF064E6200FD_label_en-US" xlink:label="lab_us-gaap_AmortizationOfIntangibleAssets_18F6641C3700F1067779BF064E6200FD" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Amortization of Intangible Assets</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AmortizationOfIntangibleAssets" xlink:label="loc_us-gaap_AmortizationOfIntangibleAssets_18F6641C3700F1067779BF064E6200FD" xlink:type="locator" />
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    <link:label id="lab_us-gaap_InventoryDisclosureTextBlock_8E26BD63965E07B489EF32A715AD6096_terseLabel_en-US" xlink:label="lab_us-gaap_InventoryDisclosureTextBlock_8E26BD63965E07B489EF32A715AD6096" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">INVENTORIES AND SUPPLIES</link:label>
    <link:label id="lab_us-gaap_InventoryDisclosureTextBlock_8E26BD63965E07B489EF32A715AD6096_label_en-US" xlink:label="lab_us-gaap_InventoryDisclosureTextBlock_8E26BD63965E07B489EF32A715AD6096" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Inventory Disclosure [Text Block]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_InventoryDisclosureTextBlock" xlink:label="loc_us-gaap_InventoryDisclosureTextBlock_8E26BD63965E07B489EF32A715AD6096" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_InventoryDisclosureTextBlock_8E26BD63965E07B489EF32A715AD6096" xlink:to="lab_us-gaap_InventoryDisclosureTextBlock_8E26BD63965E07B489EF32A715AD6096" xlink:type="arc" />
    <link:label id="lab_us-gaap_SubsidiaryOrEquityMethodInvesteeCumulativePercentageOwnershipAfterAllTransactions_ACEB612D149EDDAB1676D8E480752086_terseLabel_en-US" xlink:label="lab_us-gaap_SubsidiaryOrEquityMethodInvesteeCumulativePercentageOwnershipAfterAllTransactions_ACEB612D149EDDAB1676D8E480752086" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Guarantor, ownership interest by Clean Harbors, Inc.</link:label>
    <link:label id="lab_us-gaap_SubsidiaryOrEquityMethodInvesteeCumulativePercentageOwnershipAfterAllTransactions_ACEB612D149EDDAB1676D8E480752086_label_en-US" xlink:label="lab_us-gaap_SubsidiaryOrEquityMethodInvesteeCumulativePercentageOwnershipAfterAllTransactions_ACEB612D149EDDAB1676D8E480752086" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Subsidiary or Equity Method Investee, Cumulative Percentage Ownership after All Transactions</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SubsidiaryOrEquityMethodInvesteeCumulativePercentageOwnershipAfterAllTransactions" xlink:label="loc_us-gaap_SubsidiaryOrEquityMethodInvesteeCumulativePercentageOwnershipAfterAllTransactions_ACEB612D149EDDAB1676D8E480752086" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SubsidiaryOrEquityMethodInvesteeCumulativePercentageOwnershipAfterAllTransactions_ACEB612D149EDDAB1676D8E480752086" xlink:to="lab_us-gaap_SubsidiaryOrEquityMethodInvesteeCumulativePercentageOwnershipAfterAllTransactions_ACEB612D149EDDAB1676D8E480752086" xlink:type="arc" />
    <link:label id="lab_clh_CondensedConsolidatingBalanceSheetLineItems_B18D03DBE27EBCDE87F8D8E4807682D1_terseLabel_en-US" xlink:label="lab_clh_CondensedConsolidatingBalanceSheetLineItems_B18D03DBE27EBCDE87F8D8E4807682D1" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Condensed consolidating balance sheet</link:label>
    <link:label id="lab_clh_CondensedConsolidatingBalanceSheetLineItems_B18D03DBE27EBCDE87F8D8E4807682D1_label_en-US" xlink:label="lab_clh_CondensedConsolidatingBalanceSheetLineItems_B18D03DBE27EBCDE87F8D8E4807682D1" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Condensed Consolidating Balance Sheet [Line Items]</link:label>
    <link:label id="lab_clh_CondensedConsolidatingBalanceSheetLineItems_B18D03DBE27EBCDE87F8D8E4807682D1_documentation_en-US" xlink:label="lab_clh_CondensedConsolidatingBalanceSheetLineItems_B18D03DBE27EBCDE87F8D8E4807682D1" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">-- None. No documentation exists for this element. --</link:label>
    <link:loc xlink:href="clh-20171231.xsd#clh_CondensedConsolidatingBalanceSheetLineItems" xlink:label="loc_clh_CondensedConsolidatingBalanceSheetLineItems_B18D03DBE27EBCDE87F8D8E4807682D1" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_clh_CondensedConsolidatingBalanceSheetLineItems_B18D03DBE27EBCDE87F8D8E4807682D1" xlink:to="lab_clh_CondensedConsolidatingBalanceSheetLineItems_B18D03DBE27EBCDE87F8D8E4807682D1" xlink:type="arc" />
    <link:label id="lab_us-gaap_AssetsAbstract_6A10E40F3A5F631CC7D7D8E48076A4B6_terseLabel_en-US" xlink:label="lab_us-gaap_AssetsAbstract_6A10E40F3A5F631CC7D7D8E48076A4B6" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Assets:</link:label>
    <link:label id="lab_us-gaap_AssetsAbstract_6A10E40F3A5F631CC7D7D8E48076A4B6_label_en-US" xlink:label="lab_us-gaap_AssetsAbstract_6A10E40F3A5F631CC7D7D8E48076A4B6" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Assets [Abstract]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AssetsAbstract" xlink:label="loc_us-gaap_AssetsAbstract_6A10E40F3A5F631CC7D7D8E48076A4B6" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AssetsAbstract_6A10E40F3A5F631CC7D7D8E48076A4B6" xlink:to="lab_us-gaap_AssetsAbstract_6A10E40F3A5F631CC7D7D8E48076A4B6" xlink:type="arc" />
    <link:label id="lab_us-gaap_CashAndCashEquivalentsAtCarryingValue_1D0200D051B2D6EABC95D8E480767B35_verboseLabel_en-US" xlink:label="lab_us-gaap_CashAndCashEquivalentsAtCarryingValue_1D0200D051B2D6EABC95D8E480767B35" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Cash and cash equivalents</link:label>
    <link:label id="lab_us-gaap_CashAndCashEquivalentsAtCarryingValue_1D0200D051B2D6EABC95D8E480767B35_label_en-US" xlink:label="lab_us-gaap_CashAndCashEquivalentsAtCarryingValue_1D0200D051B2D6EABC95D8E480767B35" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Cash and Cash Equivalents, at Carrying Value</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:label="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_1D0200D051B2D6EABC95D8E480767B35" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_1D0200D051B2D6EABC95D8E480767B35" xlink:to="lab_us-gaap_CashAndCashEquivalentsAtCarryingValue_1D0200D051B2D6EABC95D8E480767B35" xlink:type="arc" />
    <link:label id="lab_us-gaap_MarketableSecuritiesCurrent_ACFF11F810C61A1E2571D8E480764470_terseLabel_en-US" xlink:label="lab_us-gaap_MarketableSecuritiesCurrent_ACFF11F810C61A1E2571D8E480764470" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Short-term marketable securities</link:label>
    <link:label id="lab_us-gaap_MarketableSecuritiesCurrent_ACFF11F810C61A1E2571D8E480764470_label_en-US" xlink:label="lab_us-gaap_MarketableSecuritiesCurrent_ACFF11F810C61A1E2571D8E480764470" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Marketable Securities, Current</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_MarketableSecuritiesCurrent" xlink:label="loc_us-gaap_MarketableSecuritiesCurrent_ACFF11F810C61A1E2571D8E480764470" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_MarketableSecuritiesCurrent_ACFF11F810C61A1E2571D8E480764470" xlink:to="lab_us-gaap_MarketableSecuritiesCurrent_ACFF11F810C61A1E2571D8E480764470" xlink:type="arc" />
    <link:label id="lab_clh_ReceivablesFromAffiliatesSubsidiariesAndHoldingCompanies_DDC3AA520CFC35D1160CD8E48076D4E7_terseLabel_en-US" xlink:label="lab_clh_ReceivablesFromAffiliatesSubsidiariesAndHoldingCompanies_DDC3AA520CFC35D1160CD8E48076D4E7" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Intercompany receivables</link:label>
    <link:label id="lab_clh_ReceivablesFromAffiliatesSubsidiariesAndHoldingCompanies_DDC3AA520CFC35D1160CD8E48076D4E7_label_en-US" xlink:label="lab_clh_ReceivablesFromAffiliatesSubsidiariesAndHoldingCompanies_DDC3AA520CFC35D1160CD8E48076D4E7" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Receivables from Affiliates Subsidiaries and Holding Companies</link:label>
    <link:label id="lab_clh_ReceivablesFromAffiliatesSubsidiariesAndHoldingCompanies_DDC3AA520CFC35D1160CD8E48076D4E7_documentation_en-US" xlink:label="lab_clh_ReceivablesFromAffiliatesSubsidiariesAndHoldingCompanies_DDC3AA520CFC35D1160CD8E48076D4E7" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">This element represents receivables from affiliates, subsidiaries and the holding company.</link:label>
    <link:loc xlink:href="clh-20171231.xsd#clh_ReceivablesFromAffiliatesSubsidiariesAndHoldingCompanies" xlink:label="loc_clh_ReceivablesFromAffiliatesSubsidiariesAndHoldingCompanies_DDC3AA520CFC35D1160CD8E48076D4E7" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_clh_ReceivablesFromAffiliatesSubsidiariesAndHoldingCompanies_DDC3AA520CFC35D1160CD8E48076D4E7" xlink:to="lab_clh_ReceivablesFromAffiliatesSubsidiariesAndHoldingCompanies_DDC3AA520CFC35D1160CD8E48076D4E7" xlink:type="arc" />
    <link:label id="lab_us-gaap_AccountsReceivableNetCurrent_2C4CC03DAE2CE0FE58A9D8E480768F10_verboseLabel_en-US" xlink:label="lab_us-gaap_AccountsReceivableNetCurrent_2C4CC03DAE2CE0FE58A9D8E480768F10" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Accounts receivable, net</link:label>
    <link:label id="lab_us-gaap_AccountsReceivableNetCurrent_2C4CC03DAE2CE0FE58A9D8E480768F10_label_en-US" xlink:label="lab_us-gaap_AccountsReceivableNetCurrent_2C4CC03DAE2CE0FE58A9D8E480768F10" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Accounts Receivable, Net, Current</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AccountsReceivableNetCurrent" xlink:label="loc_us-gaap_AccountsReceivableNetCurrent_2C4CC03DAE2CE0FE58A9D8E480768F10" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AccountsReceivableNetCurrent_2C4CC03DAE2CE0FE58A9D8E480768F10" xlink:to="lab_us-gaap_AccountsReceivableNetCurrent_2C4CC03DAE2CE0FE58A9D8E480768F10" xlink:type="arc" />
    <link:label id="lab_us-gaap_OtherAssetsCurrent_A6A19A50DA5BD2F3FB2CD8E48076A73F_terseLabel_en-US" xlink:label="lab_us-gaap_OtherAssetsCurrent_A6A19A50DA5BD2F3FB2CD8E48076A73F" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Other current assets</link:label>
    <link:label id="lab_us-gaap_OtherAssetsCurrent_A6A19A50DA5BD2F3FB2CD8E48076A73F_label_en-US" xlink:label="lab_us-gaap_OtherAssetsCurrent_A6A19A50DA5BD2F3FB2CD8E48076A73F" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Other Assets, Current</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherAssetsCurrent" xlink:label="loc_us-gaap_OtherAssetsCurrent_A6A19A50DA5BD2F3FB2CD8E48076A73F" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherAssetsCurrent_A6A19A50DA5BD2F3FB2CD8E48076A73F" xlink:to="lab_us-gaap_OtherAssetsCurrent_A6A19A50DA5BD2F3FB2CD8E48076A73F" xlink:type="arc" />
    <link:label id="lab_us-gaap_PropertyPlantAndEquipmentNet_E25B4E7528AD4110C270D8E480777E9B_verboseLabel_en-US" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentNet_E25B4E7528AD4110C270D8E480777E9B" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Property, plant and equipment, net</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PropertyPlantAndEquipmentNet" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentNet_E25B4E7528AD4110C270D8E480777E9B" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentNet_E25B4E7528AD4110C270D8E480777E9B" xlink:to="lab_us-gaap_PropertyPlantAndEquipmentNet_E25B4E7528AD4110C270D8E480777E9B" xlink:type="arc" />
    <link:label id="lab_us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures_978057F57AA666D34EADD8E480772A01_terseLabel_en-US" xlink:label="lab_us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures_978057F57AA666D34EADD8E480772A01" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Investments in subsidiaries</link:label>
    <link:label id="lab_us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures_978057F57AA666D34EADD8E480772A01_label_en-US" xlink:label="lab_us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures_978057F57AA666D34EADD8E480772A01" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures" xlink:label="loc_us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures_978057F57AA666D34EADD8E480772A01" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures_978057F57AA666D34EADD8E480772A01" xlink:to="lab_us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures_978057F57AA666D34EADD8E480772A01" xlink:type="arc" />
    <link:label id="lab_clh_DebtReceivableFromAffiliatesSubsidiariesAndHoldingCompanies_C2CEEFB20E4B02D0DCB4D8E480770AFD_terseLabel_en-US" xlink:label="lab_clh_DebtReceivableFromAffiliatesSubsidiariesAndHoldingCompanies_C2CEEFB20E4B02D0DCB4D8E480770AFD" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Intercompany debt receivable</link:label>
    <link:label id="lab_clh_DebtReceivableFromAffiliatesSubsidiariesAndHoldingCompanies_C2CEEFB20E4B02D0DCB4D8E480770AFD_label_en-US" xlink:label="lab_clh_DebtReceivableFromAffiliatesSubsidiariesAndHoldingCompanies_C2CEEFB20E4B02D0DCB4D8E480770AFD" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Debt Receivable from Affiliates Subsidiaries and Holding Companies</link:label>
    <link:label id="lab_clh_DebtReceivableFromAffiliatesSubsidiariesAndHoldingCompanies_C2CEEFB20E4B02D0DCB4D8E480770AFD_documentation_en-US" xlink:label="lab_clh_DebtReceivableFromAffiliatesSubsidiariesAndHoldingCompanies_C2CEEFB20E4B02D0DCB4D8E480770AFD" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">This element represents debts receivable from the affiliates, subsidiaries and the holding company.</link:label>
    <link:loc xlink:href="clh-20171231.xsd#clh_DebtReceivableFromAffiliatesSubsidiariesAndHoldingCompanies" xlink:label="loc_clh_DebtReceivableFromAffiliatesSubsidiariesAndHoldingCompanies_C2CEEFB20E4B02D0DCB4D8E480770AFD" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_clh_DebtReceivableFromAffiliatesSubsidiariesAndHoldingCompanies_C2CEEFB20E4B02D0DCB4D8E480770AFD" xlink:to="lab_clh_DebtReceivableFromAffiliatesSubsidiariesAndHoldingCompanies_C2CEEFB20E4B02D0DCB4D8E480770AFD" xlink:type="arc" />
    <link:label id="lab_clh_DeferredFinancingCostsandOtherAssets_A0D44CFBD60C9E892BC4D8E48077F276_terseLabel_en-US" xlink:label="lab_clh_DeferredFinancingCostsandOtherAssets_A0D44CFBD60C9E892BC4D8E48077F276" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Other long-term assets</link:label>
    <link:label id="lab_clh_DeferredFinancingCostsandOtherAssets_A0D44CFBD60C9E892BC4D8E48077F276_label_en-US" xlink:label="lab_clh_DeferredFinancingCostsandOtherAssets_A0D44CFBD60C9E892BC4D8E48077F276" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Deferred Financing Costs and Other Assets</link:label>
    <link:label id="lab_clh_DeferredFinancingCostsandOtherAssets_A0D44CFBD60C9E892BC4D8E48077F276_documentation_en-US" xlink:label="lab_clh_DeferredFinancingCostsandOtherAssets_A0D44CFBD60C9E892BC4D8E48077F276" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Deferred Financing Costs and Other Assets</link:label>
    <link:loc xlink:href="clh-20171231.xsd#clh_DeferredFinancingCostsandOtherAssets" xlink:label="loc_clh_DeferredFinancingCostsandOtherAssets_A0D44CFBD60C9E892BC4D8E48077F276" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_clh_DeferredFinancingCostsandOtherAssets_A0D44CFBD60C9E892BC4D8E48077F276" xlink:to="lab_clh_DeferredFinancingCostsandOtherAssets_A0D44CFBD60C9E892BC4D8E48077F276" xlink:type="arc" />
    <link:label id="lab_us-gaap_Assets_8CF52ACCD18DA2BC745ED8E4807790B8_totalLabel_en-US" xlink:label="lab_us-gaap_Assets_8CF52ACCD18DA2BC745ED8E4807790B8" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Total assets</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_Assets" xlink:label="loc_us-gaap_Assets_8CF52ACCD18DA2BC745ED8E4807790B8" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_Assets_8CF52ACCD18DA2BC745ED8E4807790B8" xlink:to="lab_us-gaap_Assets_8CF52ACCD18DA2BC745ED8E4807790B8" xlink:type="arc" />
    <link:label id="lab_us-gaap_LiabilitiesAndStockholdersEquityAbstract_A1F203D50302DEE5A9DAD8E480773F53_terseLabel_en-US" xlink:label="lab_us-gaap_LiabilitiesAndStockholdersEquityAbstract_A1F203D50302DEE5A9DAD8E480773F53" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Liabilities and Stockholders' Equity:</link:label>
    <link:label id="lab_us-gaap_LiabilitiesAndStockholdersEquityAbstract_A1F203D50302DEE5A9DAD8E480773F53_label_en-US" xlink:label="lab_us-gaap_LiabilitiesAndStockholdersEquityAbstract_A1F203D50302DEE5A9DAD8E480773F53" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Liabilities and Equity [Abstract]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LiabilitiesAndStockholdersEquityAbstract" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_A1F203D50302DEE5A9DAD8E480773F53" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_A1F203D50302DEE5A9DAD8E480773F53" xlink:to="lab_us-gaap_LiabilitiesAndStockholdersEquityAbstract_A1F203D50302DEE5A9DAD8E480773F53" xlink:type="arc" />
    <link:label id="lab_us-gaap_LiabilitiesCurrent_7D7D1BAA6F145E30B4EDD8E480770E83_terseLabel_en-US" xlink:label="lab_us-gaap_LiabilitiesCurrent_7D7D1BAA6F145E30B4EDD8E480770E83" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Current liabilities</link:label>
    <link:label id="lab_us-gaap_LiabilitiesCurrent_7D7D1BAA6F145E30B4EDD8E480770E83_label_en-US" xlink:label="lab_us-gaap_LiabilitiesCurrent_7D7D1BAA6F145E30B4EDD8E480770E83" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Liabilities, Current</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LiabilitiesCurrent" xlink:label="loc_us-gaap_LiabilitiesCurrent_7D7D1BAA6F145E30B4EDD8E480770E83" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LiabilitiesCurrent_7D7D1BAA6F145E30B4EDD8E480770E83" xlink:to="lab_us-gaap_LiabilitiesCurrent_7D7D1BAA6F145E30B4EDD8E480770E83" xlink:type="arc" />
    <link:label id="lab_clh_PayablesToAffiliatesSubsidiariesAndHoldingCompanies_71BE1CDBB1C2D34AE975D8E48077D146_terseLabel_en-US" xlink:label="lab_clh_PayablesToAffiliatesSubsidiariesAndHoldingCompanies_71BE1CDBB1C2D34AE975D8E48077D146" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Intercompany payables</link:label>
    <link:label id="lab_clh_PayablesToAffiliatesSubsidiariesAndHoldingCompanies_71BE1CDBB1C2D34AE975D8E48077D146_label_en-US" xlink:label="lab_clh_PayablesToAffiliatesSubsidiariesAndHoldingCompanies_71BE1CDBB1C2D34AE975D8E48077D146" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Payables to Affiliates Subsidiaries and Holding Companies</link:label>
    <link:label id="lab_clh_PayablesToAffiliatesSubsidiariesAndHoldingCompanies_71BE1CDBB1C2D34AE975D8E48077D146_documentation_en-US" xlink:label="lab_clh_PayablesToAffiliatesSubsidiariesAndHoldingCompanies_71BE1CDBB1C2D34AE975D8E48077D146" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">This element represents payables to affiliates, subsidiaries and the holding company.</link:label>
    <link:loc xlink:href="clh-20171231.xsd#clh_PayablesToAffiliatesSubsidiariesAndHoldingCompanies" xlink:label="loc_clh_PayablesToAffiliatesSubsidiariesAndHoldingCompanies_71BE1CDBB1C2D34AE975D8E48077D146" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_clh_PayablesToAffiliatesSubsidiariesAndHoldingCompanies_71BE1CDBB1C2D34AE975D8E48077D146" xlink:to="lab_clh_PayablesToAffiliatesSubsidiariesAndHoldingCompanies_71BE1CDBB1C2D34AE975D8E48077D146" xlink:type="arc" />
    <link:label id="lab_clh_ClosurePostClosureAndRemedialLiabilitiesNet_7F7F7C3F2FFCE25C3762D8E4807758FA_terseLabel_en-US" xlink:label="lab_clh_ClosurePostClosureAndRemedialLiabilitiesNet_7F7F7C3F2FFCE25C3762D8E4807758FA" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Closure, post-closure and remedial liabilities, net</link:label>
    <link:label id="lab_clh_ClosurePostClosureAndRemedialLiabilitiesNet_7F7F7C3F2FFCE25C3762D8E4807758FA_label_en-US" xlink:label="lab_clh_ClosurePostClosureAndRemedialLiabilitiesNet_7F7F7C3F2FFCE25C3762D8E4807758FA" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Closure Post Closure and Remedial Liabilities, Net</link:label>
    <link:label id="lab_clh_ClosurePostClosureAndRemedialLiabilitiesNet_7F7F7C3F2FFCE25C3762D8E4807758FA_documentation_en-US" xlink:label="lab_clh_ClosurePostClosureAndRemedialLiabilitiesNet_7F7F7C3F2FFCE25C3762D8E4807758FA" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">The net amount of closure, post-closure and remedial liabilities that is required as of the balance sheet date, which will be paid after one year or beyond the normal operating cycle, if longer.</link:label>
    <link:loc xlink:href="clh-20171231.xsd#clh_ClosurePostClosureAndRemedialLiabilitiesNet" xlink:label="loc_clh_ClosurePostClosureAndRemedialLiabilitiesNet_7F7F7C3F2FFCE25C3762D8E4807758FA" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_clh_ClosurePostClosureAndRemedialLiabilitiesNet_7F7F7C3F2FFCE25C3762D8E4807758FA" xlink:to="lab_clh_ClosurePostClosureAndRemedialLiabilitiesNet_7F7F7C3F2FFCE25C3762D8E4807758FA" xlink:type="arc" />
    <link:label id="lab_us-gaap_LongTermDebtNoncurrent_DE0881AFA0171598C4B8D8E480773D67_terseLabel_en-US" xlink:label="lab_us-gaap_LongTermDebtNoncurrent_DE0881AFA0171598C4B8D8E480773D67" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Long-term obligations, less current portion</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LongTermDebtNoncurrent" xlink:label="loc_us-gaap_LongTermDebtNoncurrent_DE0881AFA0171598C4B8D8E480773D67" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LongTermDebtNoncurrent_DE0881AFA0171598C4B8D8E480773D67" xlink:to="lab_us-gaap_LongTermDebtNoncurrent_DE0881AFA0171598C4B8D8E480773D67" xlink:type="arc" />
    <link:label id="lab_clh_DebtPayableToAffiliatesSubsidiariesAndHoldingCompanies_D52945A7BA739888884CD8E480773F95_terseLabel_en-US" xlink:label="lab_clh_DebtPayableToAffiliatesSubsidiariesAndHoldingCompanies_D52945A7BA739888884CD8E480773F95" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Intercompany debt payable</link:label>
    <link:label id="lab_clh_DebtPayableToAffiliatesSubsidiariesAndHoldingCompanies_D52945A7BA739888884CD8E480773F95_label_en-US" xlink:label="lab_clh_DebtPayableToAffiliatesSubsidiariesAndHoldingCompanies_D52945A7BA739888884CD8E480773F95" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Debt Payable to Affiliates Subsidiaries and Holding Companies</link:label>
    <link:label id="lab_clh_DebtPayableToAffiliatesSubsidiariesAndHoldingCompanies_D52945A7BA739888884CD8E480773F95_documentation_en-US" xlink:label="lab_clh_DebtPayableToAffiliatesSubsidiariesAndHoldingCompanies_D52945A7BA739888884CD8E480773F95" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">This element represents the debts payable to the affiliates, subsidiaries and the holding company.</link:label>
    <link:loc xlink:href="clh-20171231.xsd#clh_DebtPayableToAffiliatesSubsidiariesAndHoldingCompanies" xlink:label="loc_clh_DebtPayableToAffiliatesSubsidiariesAndHoldingCompanies_D52945A7BA739888884CD8E480773F95" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_clh_DebtPayableToAffiliatesSubsidiariesAndHoldingCompanies_D52945A7BA739888884CD8E480773F95" xlink:to="lab_clh_DebtPayableToAffiliatesSubsidiariesAndHoldingCompanies_D52945A7BA739888884CD8E480773F95" xlink:type="arc" />
    <link:label id="lab_clh_UnrecognizedTaxBenefitsAndOtherLongTermLiabilitiesNoncurrent_BDF31BE3A330CEF753BED8E4807704C9_verboseLabel_en-US" xlink:label="lab_clh_UnrecognizedTaxBenefitsAndOtherLongTermLiabilitiesNoncurrent_BDF31BE3A330CEF753BED8E4807704C9" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Other long-term liabilities</link:label>
    <link:label id="lab_clh_UnrecognizedTaxBenefitsAndOtherLongTermLiabilitiesNoncurrent_BDF31BE3A330CEF753BED8E4807704C9_label_en-US" xlink:label="lab_clh_UnrecognizedTaxBenefitsAndOtherLongTermLiabilitiesNoncurrent_BDF31BE3A330CEF753BED8E4807704C9" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Unrecognized Tax Benefits and Other Long-term Liabilities, Noncurrent</link:label>
    <link:label id="lab_clh_UnrecognizedTaxBenefitsAndOtherLongTermLiabilitiesNoncurrent_BDF31BE3A330CEF753BED8E4807704C9_documentation_en-US" xlink:label="lab_clh_UnrecognizedTaxBenefitsAndOtherLongTermLiabilitiesNoncurrent_BDF31BE3A330CEF753BED8E4807704C9" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">The noncurrent portion of the amount that is recognized for the unrecognized tax benefits and other long-term liabilities as of the balance sheet date.</link:label>
    <link:loc xlink:href="clh-20171231.xsd#clh_UnrecognizedTaxBenefitsAndOtherLongTermLiabilitiesNoncurrent" xlink:label="loc_clh_UnrecognizedTaxBenefitsAndOtherLongTermLiabilitiesNoncurrent_BDF31BE3A330CEF753BED8E4807704C9" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_clh_UnrecognizedTaxBenefitsAndOtherLongTermLiabilitiesNoncurrent_BDF31BE3A330CEF753BED8E4807704C9" xlink:to="lab_clh_UnrecognizedTaxBenefitsAndOtherLongTermLiabilitiesNoncurrent_BDF31BE3A330CEF753BED8E4807704C9" xlink:type="arc" />
    <link:label id="lab_us-gaap_Liabilities_1E85825A0CDE05AB17DCD8E48077C98F_totalLabel_en-US" xlink:label="lab_us-gaap_Liabilities_1E85825A0CDE05AB17DCD8E48077C98F" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Total liabilities</link:label>
    <link:label id="lab_us-gaap_Liabilities_1E85825A0CDE05AB17DCD8E48077C98F_label_en-US" xlink:label="lab_us-gaap_Liabilities_1E85825A0CDE05AB17DCD8E48077C98F" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Liabilities</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_Liabilities" xlink:label="loc_us-gaap_Liabilities_1E85825A0CDE05AB17DCD8E48077C98F" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_Liabilities_1E85825A0CDE05AB17DCD8E48077C98F" xlink:to="lab_us-gaap_Liabilities_1E85825A0CDE05AB17DCD8E48077C98F" xlink:type="arc" />
    <link:label id="lab_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_95DAE7679A510D620546D8E4807728D3_terseLabel_en-US" xlink:label="lab_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_95DAE7679A510D620546D8E4807728D3" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Stockholders' equity</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" xlink:label="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_95DAE7679A510D620546D8E4807728D3" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_95DAE7679A510D620546D8E4807728D3" xlink:to="lab_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_95DAE7679A510D620546D8E4807728D3" xlink:type="arc" />
    <link:label id="lab_us-gaap_LiabilitiesAndStockholdersEquity_4C2C3B98AA7AB7DE9F87D8E48077C748_totalLabel_en-US" xlink:label="lab_us-gaap_LiabilitiesAndStockholdersEquity_4C2C3B98AA7AB7DE9F87D8E48077C748" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Total liabilities and stockholders' equity</link:label>
    <link:label id="lab_us-gaap_LiabilitiesAndStockholdersEquity_4C2C3B98AA7AB7DE9F87D8E48077C748_label_en-US" xlink:label="lab_us-gaap_LiabilitiesAndStockholdersEquity_4C2C3B98AA7AB7DE9F87D8E48077C748" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Liabilities and Equity</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LiabilitiesAndStockholdersEquity" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquity_4C2C3B98AA7AB7DE9F87D8E48077C748" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquity_4C2C3B98AA7AB7DE9F87D8E48077C748" xlink:to="lab_us-gaap_LiabilitiesAndStockholdersEquity_4C2C3B98AA7AB7DE9F87D8E48077C748" xlink:type="arc" />
    <link:label id="lab_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsPrepaidExpenseAndOtherAssets_228C36709F4C2CC04F9ED7FB6E13CDB6_verboseLabel_en-US" xlink:label="lab_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsPrepaidExpenseAndOtherAssets_228C36709F4C2CC04F9ED7FB6E13CDB6" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Prepaid expenses and other current assets</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsPrepaidExpenseAndOtherAssets" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsPrepaidExpenseAndOtherAssets_228C36709F4C2CC04F9ED7FB6E13CDB6" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsPrepaidExpenseAndOtherAssets_228C36709F4C2CC04F9ED7FB6E13CDB6" xlink:to="lab_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsPrepaidExpenseAndOtherAssets_228C36709F4C2CC04F9ED7FB6E13CDB6" xlink:type="arc" />
    <link:label id="lab_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment_65E75E571C36A220A9B5D7FB6E137FCD_verboseLabel_en-US" xlink:label="lab_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment_65E75E571C36A220A9B5D7FB6E137FCD" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Property, plant and equipment</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment_65E75E571C36A220A9B5D7FB6E137FCD" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment_65E75E571C36A220A9B5D7FB6E137FCD" xlink:to="lab_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment_65E75E571C36A220A9B5D7FB6E137FCD" xlink:type="arc" />
    <link:label id="lab_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibleAssetsOtherThanGoodwill_3000753E87D309A33F5DD7FB6E13B48E_verboseLabel_en-US" xlink:label="lab_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibleAssetsOtherThanGoodwill_3000753E87D309A33F5DD7FB6E13B48E" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Permits and other intangibles</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibleAssetsOtherThanGoodwill" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibleAssetsOtherThanGoodwill_3000753E87D309A33F5DD7FB6E13B48E" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibleAssetsOtherThanGoodwill_3000753E87D309A33F5DD7FB6E13B48E" xlink:to="lab_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibleAssetsOtherThanGoodwill_3000753E87D309A33F5DD7FB6E13B48E" xlink:type="arc" />
    <link:label id="lab_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilities_BCF6D947004CB88036AED7FB6E13BA19_negatedLabel_en-US" xlink:label="lab_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilities_BCF6D947004CB88036AED7FB6E13BA19" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Current liabilities</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilities" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilities_BCF6D947004CB88036AED7FB6E13BA19" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilities_BCF6D947004CB88036AED7FB6E13BA19" xlink:to="lab_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilities_BCF6D947004CB88036AED7FB6E13BA19" xlink:type="arc" />
    <link:label id="lab_us-gaap_SiteContingencyTable_FC6C0EF37749CE48D75D48C3F092B259_terseLabel_en-US" xlink:label="lab_us-gaap_SiteContingencyTable_FC6C0EF37749CE48D75D48C3F092B259" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Site Contingency [Table]</link:label>
    <link:label id="lab_us-gaap_SiteContingencyTable_FC6C0EF37749CE48D75D48C3F092B259_label_en-US" xlink:label="lab_us-gaap_SiteContingencyTable_FC6C0EF37749CE48D75D48C3F092B259" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Site Contingency [Table]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SiteContingencyTable" xlink:label="loc_us-gaap_SiteContingencyTable_FC6C0EF37749CE48D75D48C3F092B259" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SiteContingencyTable_FC6C0EF37749CE48D75D48C3F092B259" xlink:to="lab_us-gaap_SiteContingencyTable_FC6C0EF37749CE48D75D48C3F092B259" xlink:type="arc" />
    <link:label id="lab_us-gaap_EnvironmentalRemediationSiteAxis_B70596C64168FD27CEF948C3F0927B40_terseLabel_en-US" xlink:label="lab_us-gaap_EnvironmentalRemediationSiteAxis_B70596C64168FD27CEF948C3F0927B40" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Environmental Remediation Site [Axis]</link:label>
    <link:label id="lab_us-gaap_EnvironmentalRemediationSiteAxis_B70596C64168FD27CEF948C3F0927B40_label_en-US" xlink:label="lab_us-gaap_EnvironmentalRemediationSiteAxis_B70596C64168FD27CEF948C3F0927B40" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Environmental Remediation Site [Axis]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EnvironmentalRemediationSiteAxis" xlink:label="loc_us-gaap_EnvironmentalRemediationSiteAxis_B70596C64168FD27CEF948C3F0927B40" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EnvironmentalRemediationSiteAxis_B70596C64168FD27CEF948C3F0927B40" xlink:to="lab_us-gaap_EnvironmentalRemediationSiteAxis_B70596C64168FD27CEF948C3F0927B40" xlink:type="arc" />
    <link:label id="lab_us-gaap_EnvironmentalRemediationSiteDomain_5C87B7A60187B4E42D5E48C3F092FEBF_terseLabel_en-US" xlink:label="lab_us-gaap_EnvironmentalRemediationSiteDomain_5C87B7A60187B4E42D5E48C3F092FEBF" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Environmental Remediation Site [Domain]</link:label>
    <link:label id="lab_us-gaap_EnvironmentalRemediationSiteDomain_5C87B7A60187B4E42D5E48C3F092FEBF_label_en-US" xlink:label="lab_us-gaap_EnvironmentalRemediationSiteDomain_5C87B7A60187B4E42D5E48C3F092FEBF" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Environmental Remediation Site [Domain]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EnvironmentalRemediationSiteDomain" xlink:label="loc_us-gaap_EnvironmentalRemediationSiteDomain_5C87B7A60187B4E42D5E48C3F092FEBF" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EnvironmentalRemediationSiteDomain_5C87B7A60187B4E42D5E48C3F092FEBF" xlink:to="lab_us-gaap_EnvironmentalRemediationSiteDomain_5C87B7A60187B4E42D5E48C3F092FEBF" xlink:type="arc" />
    <link:label id="lab_clh_RemedialLiabilitiesForLandfillSitesMember_DB33725167DB2E4AE9E048C3F0929A96_terseLabel_en-US" xlink:label="lab_clh_RemedialLiabilitiesForLandfillSitesMember_DB33725167DB2E4AE9E048C3F0929A96" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Remedial Liabilities for Landfill Sites</link:label>
    <link:label id="lab_clh_RemedialLiabilitiesForLandfillSitesMember_DB33725167DB2E4AE9E048C3F0929A96_label_en-US" xlink:label="lab_clh_RemedialLiabilitiesForLandfillSitesMember_DB33725167DB2E4AE9E048C3F0929A96" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Remedial Liabilities for Landfill Sites [Member]</link:label>
    <link:label id="lab_clh_RemedialLiabilitiesForLandfillSitesMember_DB33725167DB2E4AE9E048C3F0929A96_documentation_en-US" xlink:label="lab_clh_RemedialLiabilitiesForLandfillSitesMember_DB33725167DB2E4AE9E048C3F0929A96" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">This element represents the details that pertain to the remedial liability for landfill sites.</link:label>
    <link:loc xlink:href="clh-20171231.xsd#clh_RemedialLiabilitiesForLandfillSitesMember" xlink:label="loc_clh_RemedialLiabilitiesForLandfillSitesMember_DB33725167DB2E4AE9E048C3F0929A96" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_clh_RemedialLiabilitiesForLandfillSitesMember_DB33725167DB2E4AE9E048C3F0929A96" xlink:to="lab_clh_RemedialLiabilitiesForLandfillSitesMember_DB33725167DB2E4AE9E048C3F0929A96" xlink:type="arc" />
    <link:label id="lab_clh_RemedialLiabilitiesForInactiveSitesMember_BE880605173948B20E3148C3F0936092_terseLabel_en-US" xlink:label="lab_clh_RemedialLiabilitiesForInactiveSitesMember_BE880605173948B20E3148C3F0936092" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Remedial Liabilities for Inactive Sites</link:label>
    <link:label id="lab_clh_RemedialLiabilitiesForInactiveSitesMember_BE880605173948B20E3148C3F0936092_label_en-US" xlink:label="lab_clh_RemedialLiabilitiesForInactiveSitesMember_BE880605173948B20E3148C3F0936092" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Remedial Liabilities for Inactive Sites [Member]</link:label>
    <link:label id="lab_clh_RemedialLiabilitiesForInactiveSitesMember_BE880605173948B20E3148C3F0936092_documentation_en-US" xlink:label="lab_clh_RemedialLiabilitiesForInactiveSitesMember_BE880605173948B20E3148C3F0936092" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">This element represents the details that pertain to the remedial liabilities for inactive sites.</link:label>
    <link:loc xlink:href="clh-20171231.xsd#clh_RemedialLiabilitiesForInactiveSitesMember" xlink:label="loc_clh_RemedialLiabilitiesForInactiveSitesMember_BE880605173948B20E3148C3F0936092" xlink:type="locator" />
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    <link:label id="lab_clh_RemedialLiabilitiesIncludingSuperfundForNonLandfillOperationsMember_9C579216B74C004D7D7548C3F0933BC8_terseLabel_en-US" xlink:label="lab_clh_RemedialLiabilitiesIncludingSuperfundForNonLandfillOperationsMember_9C579216B74C004D7D7548C3F0933BC8" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Remedial Liabilities (Including Superfund) for Non-Landfill Operations</link:label>
    <link:label id="lab_clh_RemedialLiabilitiesIncludingSuperfundForNonLandfillOperationsMember_9C579216B74C004D7D7548C3F0933BC8_label_en-US" xlink:label="lab_clh_RemedialLiabilitiesIncludingSuperfundForNonLandfillOperationsMember_9C579216B74C004D7D7548C3F0933BC8" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Remedial Liabilities (Including Superfund) for Non-Landfill Operations [Member]</link:label>
    <link:label id="lab_clh_RemedialLiabilitiesIncludingSuperfundForNonLandfillOperationsMember_9C579216B74C004D7D7548C3F0933BC8_documentation_en-US" xlink:label="lab_clh_RemedialLiabilitiesIncludingSuperfundForNonLandfillOperationsMember_9C579216B74C004D7D7548C3F0933BC8" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">This element represents the details that pertain to the remedial liabilities for non-landfill sites.</link:label>
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    <link:label id="lab_us-gaap_AccrualForEnvironmentalLossContingenciesChargesToExpenseForNewLosses_18D176019E1AB41BC82748C3F0939DDD_terseLabel_en-US" xlink:label="lab_us-gaap_AccrualForEnvironmentalLossContingenciesChargesToExpenseForNewLosses_18D176019E1AB41BC82748C3F0939DDD" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Accretion</link:label>
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    <link:label id="lab_clh_IndustrialandFieldServicesMember_7587308FB30612747C07B4762E6E9B93_terseLabel_en-US" xlink:label="lab_clh_IndustrialandFieldServicesMember_7587308FB30612747C07B4762E6E9B93" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Industrial and Field Services</link:label>
    <link:loc xlink:href="clh-20171231.xsd#clh_IndustrialandFieldServicesMember" xlink:label="loc_clh_IndustrialandFieldServicesMember_7587308FB30612747C07B4762E6E9B93" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_clh_IndustrialandFieldServicesMember_7587308FB30612747C07B4762E6E9B93" xlink:to="lab_clh_IndustrialandFieldServicesMember_7587308FB30612747C07B4762E6E9B93" xlink:type="arc" />
    <link:label id="lab_clh_SafetyKleenMember_BAA4829CB561045F83BEB4762E6E672C_verboseLabel_en-US" xlink:label="lab_clh_SafetyKleenMember_BAA4829CB561045F83BEB4762E6E672C" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Safety-Kleen</link:label>
    <link:loc xlink:href="clh-20171231.xsd#clh_SafetyKleenMember" xlink:label="loc_clh_SafetyKleenMember_BAA4829CB561045F83BEB4762E6E672C" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_clh_SafetyKleenMember_BAA4829CB561045F83BEB4762E6E672C" xlink:to="lab_clh_SafetyKleenMember_BAA4829CB561045F83BEB4762E6E672C" xlink:type="arc" />
    <link:label id="lab_clh_OilGasandLodgingSegmentMember_BDC64F25D911C47C470EB4762E6E3470_verboseLabel_en-US" xlink:label="lab_clh_OilGasandLodgingSegmentMember_BDC64F25D911C47C470EB4762E6E3470" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Oil, Gas and Lodging Services</link:label>
    <link:loc xlink:href="clh-20171231.xsd#clh_OilGasandLodgingSegmentMember" xlink:label="loc_clh_OilGasandLodgingSegmentMember_BDC64F25D911C47C470EB4762E6E3470" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_clh_OilGasandLodgingSegmentMember_BDC64F25D911C47C470EB4762E6E3470" xlink:to="lab_clh_OilGasandLodgingSegmentMember_BDC64F25D911C47C470EB4762E6E3470" xlink:type="arc" />
    <link:label id="lab_us-gaap_CorporateMember_80B70544A228397E953BB4762E6E0E29_terseLabel_en-US" xlink:label="lab_us-gaap_CorporateMember_80B70544A228397E953BB4762E6E0E29" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Corporate Items</link:label>
    <link:label id="lab_us-gaap_CorporateMember_80B70544A228397E953BB4762E6E0E29_label_en-US" xlink:label="lab_us-gaap_CorporateMember_80B70544A228397E953BB4762E6E0E29" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Corporate Segment [Member]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CorporateMember" xlink:label="loc_us-gaap_CorporateMember_80B70544A228397E953BB4762E6E0E29" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CorporateMember_80B70544A228397E953BB4762E6E0E29" xlink:to="lab_us-gaap_CorporateMember_80B70544A228397E953BB4762E6E0E29" xlink:type="arc" />
    <link:label id="lab_us-gaap_SegmentReportingInformationLineItems_FDC691A326D509E9A11FB4762E6E9B46_terseLabel_en-US" xlink:label="lab_us-gaap_SegmentReportingInformationLineItems_FDC691A326D509E9A11FB4762E6E9B46" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Segment Reporting Information [Line Items]</link:label>
    <link:label id="lab_us-gaap_SegmentReportingInformationLineItems_FDC691A326D509E9A11FB4762E6E9B46_label_en-US" xlink:label="lab_us-gaap_SegmentReportingInformationLineItems_FDC691A326D509E9A11FB4762E6E9B46" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Segment Reporting Information [Line Items]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SegmentReportingInformationLineItems" xlink:label="loc_us-gaap_SegmentReportingInformationLineItems_FDC691A326D509E9A11FB4762E6E9B46" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_FDC691A326D509E9A11FB4762E6E9B46" xlink:to="lab_us-gaap_SegmentReportingInformationLineItems_FDC691A326D509E9A11FB4762E6E9B46" xlink:type="arc" />
    <link:label id="lab_us-gaap_NumberOfReportableSegments_54D5998EDE1D6262D011B4762E6EFB0E_terseLabel_en-US" xlink:label="lab_us-gaap_NumberOfReportableSegments_54D5998EDE1D6262D011B4762E6EFB0E" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Reporting segments number</link:label>
    <link:label id="lab_us-gaap_NumberOfReportableSegments_54D5998EDE1D6262D011B4762E6EFB0E_label_en-US" xlink:label="lab_us-gaap_NumberOfReportableSegments_54D5998EDE1D6262D011B4762E6EFB0E" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Number of Reportable Segments</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NumberOfReportableSegments" xlink:label="loc_us-gaap_NumberOfReportableSegments_54D5998EDE1D6262D011B4762E6EFB0E" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_NumberOfReportableSegments_54D5998EDE1D6262D011B4762E6EFB0E" xlink:to="lab_us-gaap_NumberOfReportableSegments_54D5998EDE1D6262D011B4762E6EFB0E" xlink:type="arc" />
    <link:label id="lab_clh_NumberOfOperationsNotManagedByReportableSegments_7F8021195DECE0D36131B4762E6E6AA0_terseLabel_en-US" xlink:label="lab_clh_NumberOfOperationsNotManagedByReportableSegments_7F8021195DECE0D36131B4762E6E6AA0" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Number of operations for which the revenues are insignificant</link:label>
    <link:label id="lab_clh_NumberOfOperationsNotManagedByReportableSegments_7F8021195DECE0D36131B4762E6E6AA0_label_en-US" xlink:label="lab_clh_NumberOfOperationsNotManagedByReportableSegments_7F8021195DECE0D36131B4762E6E6AA0" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Number of Operations Not Managed by Reportable Segments</link:label>
    <link:label id="lab_clh_NumberOfOperationsNotManagedByReportableSegments_7F8021195DECE0D36131B4762E6E6AA0_documentation_en-US" xlink:label="lab_clh_NumberOfOperationsNotManagedByReportableSegments_7F8021195DECE0D36131B4762E6E6AA0" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">This element represents the number of operations not managed by reportable segments.</link:label>
    <link:loc xlink:href="clh-20171231.xsd#clh_NumberOfOperationsNotManagedByReportableSegments" xlink:label="loc_clh_NumberOfOperationsNotManagedByReportableSegments_7F8021195DECE0D36131B4762E6E6AA0" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_clh_NumberOfOperationsNotManagedByReportableSegments_7F8021195DECE0D36131B4762E6E6AA0" xlink:to="lab_clh_NumberOfOperationsNotManagedByReportableSegments_7F8021195DECE0D36131B4762E6E6AA0" xlink:type="arc" />
    <link:label id="lab_clh_IncomeLossFromContinuingOperationsBeforeInterestTaxDepreciationAndAmortizationNet_AF7F086BDC5A354A635AB4762E6E7202_terseLabel_en-US" xlink:label="lab_clh_IncomeLossFromContinuingOperationsBeforeInterestTaxDepreciationAndAmortizationNet_AF7F086BDC5A354A635AB4762E6E7202" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Adjusted EBITDA</link:label>
    <link:label id="lab_clh_IncomeLossFromContinuingOperationsBeforeInterestTaxDepreciationAndAmortizationNet_AF7F086BDC5A354A635AB4762E6E7202_label_en-US" xlink:label="lab_clh_IncomeLossFromContinuingOperationsBeforeInterestTaxDepreciationAndAmortizationNet_AF7F086BDC5A354A635AB4762E6E7202" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Income (Loss) from Continuing Operations before Interest, Tax, Depreciation and Amortization, Net</link:label>
    <link:label id="lab_clh_IncomeLossFromContinuingOperationsBeforeInterestTaxDepreciationAndAmortizationNet_AF7F086BDC5A354A635AB4762E6E7202_documentation_en-US" xlink:label="lab_clh_IncomeLossFromContinuingOperationsBeforeInterestTaxDepreciationAndAmortizationNet_AF7F086BDC5A354A635AB4762E6E7202" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">This element represents the income or loss from continuing operations before interest, taxes, depreciation and amortization to the economic entity.</link:label>
    <link:loc xlink:href="clh-20171231.xsd#clh_IncomeLossFromContinuingOperationsBeforeInterestTaxDepreciationAndAmortizationNet" xlink:label="loc_clh_IncomeLossFromContinuingOperationsBeforeInterestTaxDepreciationAndAmortizationNet_AF7F086BDC5A354A635AB4762E6E7202" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_clh_IncomeLossFromContinuingOperationsBeforeInterestTaxDepreciationAndAmortizationNet_AF7F086BDC5A354A635AB4762E6E7202" xlink:to="lab_clh_IncomeLossFromContinuingOperationsBeforeInterestTaxDepreciationAndAmortizationNet_AF7F086BDC5A354A635AB4762E6E7202" xlink:type="arc" />
    <link:label id="lab_clh_ReconciliationOfNetIncomeToAdjustedEbitdaAbstract_A40AD2D29086D0A6D414B4762E6E5729_terseLabel_en-US" xlink:label="lab_clh_ReconciliationOfNetIncomeToAdjustedEbitdaAbstract_A40AD2D29086D0A6D414B4762E6E5729" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Reconciliation to Consolidated Statements of Operations:</link:label>
    <link:label id="lab_clh_ReconciliationOfNetIncomeToAdjustedEbitdaAbstract_A40AD2D29086D0A6D414B4762E6E5729_label_en-US" xlink:label="lab_clh_ReconciliationOfNetIncomeToAdjustedEbitdaAbstract_A40AD2D29086D0A6D414B4762E6E5729" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Reconciliation of Net Income to Adjusted EBITDA [Abstract]</link:label>
    <link:label id="lab_clh_ReconciliationOfNetIncomeToAdjustedEbitdaAbstract_A40AD2D29086D0A6D414B4762E6E5729_documentation_en-US" xlink:label="lab_clh_ReconciliationOfNetIncomeToAdjustedEbitdaAbstract_A40AD2D29086D0A6D414B4762E6E5729" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">-- None. No documentation exists for this element. --</link:label>
    <link:loc xlink:href="clh-20171231.xsd#clh_ReconciliationOfNetIncomeToAdjustedEbitdaAbstract" xlink:label="loc_clh_ReconciliationOfNetIncomeToAdjustedEbitdaAbstract_A40AD2D29086D0A6D414B4762E6E5729" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_clh_ReconciliationOfNetIncomeToAdjustedEbitdaAbstract_A40AD2D29086D0A6D414B4762E6E5729" xlink:to="lab_clh_ReconciliationOfNetIncomeToAdjustedEbitdaAbstract_A40AD2D29086D0A6D414B4762E6E5729" xlink:type="arc" />
    <link:label id="lab_us-gaap_OtherNonoperatingIncomeExpense_64EFD1A8ABD5FB94CDAAB4762E6E9C29_negatedLabel_en-US" xlink:label="lab_us-gaap_OtherNonoperatingIncomeExpense_64EFD1A8ABD5FB94CDAAB4762E6E9C29" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Other expense (income), net</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherNonoperatingIncomeExpense" xlink:label="loc_us-gaap_OtherNonoperatingIncomeExpense_64EFD1A8ABD5FB94CDAAB4762E6E9C29" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherNonoperatingIncomeExpense_64EFD1A8ABD5FB94CDAAB4762E6E9C29" xlink:to="lab_us-gaap_OtherNonoperatingIncomeExpense_64EFD1A8ABD5FB94CDAAB4762E6E9C29" xlink:type="arc" />
    <link:label id="lab_us-gaap_GainLossOnSaleOfBusiness_C3F35EED5459B8E25656B4762E6ED125_negatedLabel_en-US" xlink:label="lab_us-gaap_GainLossOnSaleOfBusiness_C3F35EED5459B8E25656B4762E6ED125" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Gain on sale of businesses</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_GainLossOnSaleOfBusiness" xlink:label="loc_us-gaap_GainLossOnSaleOfBusiness_C3F35EED5459B8E25656B4762E6ED125" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_GainLossOnSaleOfBusiness_C3F35EED5459B8E25656B4762E6ED125" xlink:to="lab_us-gaap_GainLossOnSaleOfBusiness_C3F35EED5459B8E25656B4762E6ED125" xlink:type="arc" />
    <link:label id="lab_clh_InterestExpenseNet_217EE2C94DCF9C5C0BD5B4762E6E648F_terseLabel_en-US" xlink:label="lab_clh_InterestExpenseNet_217EE2C94DCF9C5C0BD5B4762E6E648F" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Interest expense, net of interest income</link:label>
    <link:loc xlink:href="clh-20171231.xsd#clh_InterestExpenseNet" xlink:label="loc_clh_InterestExpenseNet_217EE2C94DCF9C5C0BD5B4762E6E648F" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_clh_InterestExpenseNet_217EE2C94DCF9C5C0BD5B4762E6E648F" xlink:to="lab_clh_InterestExpenseNet_217EE2C94DCF9C5C0BD5B4762E6E648F" xlink:type="arc" />
    <link:label id="lab_us-gaap_StatementOfCashFlowsAbstract_E5FF8AA339913D2DD730D8E481BC2911_label_en-US" xlink:label="lab_us-gaap_StatementOfCashFlowsAbstract_E5FF8AA339913D2DD730D8E481BC2911" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Statement of Cash Flows [Abstract]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementOfCashFlowsAbstract" xlink:label="loc_us-gaap_StatementOfCashFlowsAbstract_E5FF8AA339913D2DD730D8E481BC2911" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StatementOfCashFlowsAbstract_E5FF8AA339913D2DD730D8E481BC2911" xlink:to="lab_us-gaap_StatementOfCashFlowsAbstract_E5FF8AA339913D2DD730D8E481BC2911" xlink:type="arc" />
    <link:label id="lab_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_B0BBA1253AAEDF447D54D8E481BC8F11_terseLabel_en-US" xlink:label="lab_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_B0BBA1253AAEDF447D54D8E481BC8F11" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Cash flows from operating activities:</link:label>
    <link:label id="lab_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_B0BBA1253AAEDF447D54D8E481BC8F11_label_en-US" xlink:label="lab_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_B0BBA1253AAEDF447D54D8E481BC8F11" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Net Cash Provided by (Used in) Operating Activities [Abstract]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract" xlink:label="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_B0BBA1253AAEDF447D54D8E481BC8F11" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_B0BBA1253AAEDF447D54D8E481BC8F11" xlink:to="lab_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_B0BBA1253AAEDF447D54D8E481BC8F11" xlink:type="arc" />
    <link:label id="lab_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_14F4EF611F8ADE3B22E0D8E481BC7C03_terseLabel_en-US" xlink:label="lab_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_14F4EF611F8ADE3B22E0D8E481BC7C03" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Adjustments to reconcile net income (loss) to net cash from operating activities:</link:label>
    <link:label id="lab_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_14F4EF611F8ADE3B22E0D8E481BC7C03_label_en-US" xlink:label="lab_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_14F4EF611F8ADE3B22E0D8E481BC7C03" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" xlink:label="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_14F4EF611F8ADE3B22E0D8E481BC7C03" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_14F4EF611F8ADE3B22E0D8E481BC7C03" xlink:to="lab_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_14F4EF611F8ADE3B22E0D8E481BC7C03" xlink:type="arc" />
    <link:label id="lab_us-gaap_ProvisionForDoubtfulAccounts_1AAE886266D8AE360C25D8E481BDC372_terseLabel_en-US" xlink:label="lab_us-gaap_ProvisionForDoubtfulAccounts_1AAE886266D8AE360C25D8E481BDC372" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Allowance for doubtful accounts</link:label>
    <link:label id="lab_us-gaap_ProvisionForDoubtfulAccounts_1AAE886266D8AE360C25D8E481BDC372_label_en-US" xlink:label="lab_us-gaap_ProvisionForDoubtfulAccounts_1AAE886266D8AE360C25D8E481BDC372" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Provision for Doubtful Accounts</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ProvisionForDoubtfulAccounts" xlink:label="loc_us-gaap_ProvisionForDoubtfulAccounts_1AAE886266D8AE360C25D8E481BDC372" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ProvisionForDoubtfulAccounts_1AAE886266D8AE360C25D8E481BDC372" xlink:to="lab_us-gaap_ProvisionForDoubtfulAccounts_1AAE886266D8AE360C25D8E481BDC372" xlink:type="arc" />
    <link:label id="lab_us-gaap_AmortizationOfFinancingCostsAndDiscounts_F61532CB758318C8D0EAD8E481BD6D6C_terseLabel_en-US" xlink:label="lab_us-gaap_AmortizationOfFinancingCostsAndDiscounts_F61532CB758318C8D0EAD8E481BD6D6C" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Amortization of deferred financing costs and debt discount</link:label>
    <link:label id="lab_us-gaap_AmortizationOfFinancingCostsAndDiscounts_F61532CB758318C8D0EAD8E481BD6D6C_label_en-US" xlink:label="lab_us-gaap_AmortizationOfFinancingCostsAndDiscounts_F61532CB758318C8D0EAD8E481BD6D6C" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Amortization of Debt Issuance Costs and Discounts</link:label>
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    <link:label id="lab_us-gaap_OtherIncreaseDecreaseInEnvironmentalLiabilities_E96C477CBAD140D8E051D8E481BD8502_terseLabel_en-US" xlink:label="lab_us-gaap_OtherIncreaseDecreaseInEnvironmentalLiabilities_E96C477CBAD140D8E051D8E481BD8502" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Changes in environmental liability estimates</link:label>
    <link:label id="lab_us-gaap_OtherIncreaseDecreaseInEnvironmentalLiabilities_E96C477CBAD140D8E051D8E481BD8502_label_en-US" xlink:label="lab_us-gaap_OtherIncreaseDecreaseInEnvironmentalLiabilities_E96C477CBAD140D8E051D8E481BD8502" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Other Increase (Decrease) in Environmental Liabilities</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherIncreaseDecreaseInEnvironmentalLiabilities" xlink:label="loc_us-gaap_OtherIncreaseDecreaseInEnvironmentalLiabilities_E96C477CBAD140D8E051D8E481BD8502" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherIncreaseDecreaseInEnvironmentalLiabilities_E96C477CBAD140D8E051D8E481BD8502" xlink:to="lab_us-gaap_OtherIncreaseDecreaseInEnvironmentalLiabilities_E96C477CBAD140D8E051D8E481BD8502" xlink:type="arc" />
    <link:label id="lab_us-gaap_DeferredIncomeTaxExpenseBenefit_CF1E920B0B631E278BF2D8E481BDFA5C_terseLabel_en-US" xlink:label="lab_us-gaap_DeferredIncomeTaxExpenseBenefit_CF1E920B0B631E278BF2D8E481BDFA5C" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Deferred income taxes</link:label>
    <link:label id="lab_us-gaap_DeferredIncomeTaxExpenseBenefit_CF1E920B0B631E278BF2D8E481BDFA5C_label_en-US" xlink:label="lab_us-gaap_DeferredIncomeTaxExpenseBenefit_CF1E920B0B631E278BF2D8E481BDFA5C" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Deferred Income Tax Expense (Benefit)</link:label>
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    <link:label id="lab_clh_GainLossOnSaleOfFixedAssetsAndAssetsHeldForSale_92D55FF9786FF9C2DEBBD8E481BDD387_negatedLabel_en-US" xlink:label="lab_clh_GainLossOnSaleOfFixedAssetsAndAssetsHeldForSale_92D55FF9786FF9C2DEBBD8E481BDD387" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Other expense (income), net</link:label>
    <link:label id="lab_clh_GainLossOnSaleOfFixedAssetsAndAssetsHeldForSale_92D55FF9786FF9C2DEBBD8E481BDD387_label_en-US" xlink:label="lab_clh_GainLossOnSaleOfFixedAssetsAndAssetsHeldForSale_92D55FF9786FF9C2DEBBD8E481BDD387" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Gain (Loss) on Sale of Fixed Assets and Assets Held for Sale</link:label>
    <link:label id="lab_clh_GainLossOnSaleOfFixedAssetsAndAssetsHeldForSale_92D55FF9786FF9C2DEBBD8E481BDD387_documentation_en-US" xlink:label="lab_clh_GainLossOnSaleOfFixedAssetsAndAssetsHeldForSale_92D55FF9786FF9C2DEBBD8E481BDD387" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">The difference between the sale price or salvage price and the book value of a property, plant, and equipment and assets held for sale, that was sold or retired during the reporting period. This element refers to the gain (loss).</link:label>
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    <link:label id="lab_us-gaap_ShareBasedCompensation_59755E1A2132C8356C1CD8E481BDFFA6_terseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensation_59755E1A2132C8356C1CD8E481BDFFA6" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Stock-based compensation</link:label>
    <link:label id="lab_us-gaap_ShareBasedCompensation_59755E1A2132C8356C1CD8E481BDFFA6_label_en-US" xlink:label="lab_us-gaap_ShareBasedCompensation_59755E1A2132C8356C1CD8E481BDFFA6" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-based Compensation</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareBasedCompensation" xlink:label="loc_us-gaap_ShareBasedCompensation_59755E1A2132C8356C1CD8E481BDFFA6" xlink:type="locator" />
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    <link:label id="lab_us-gaap_ExcessTaxBenefitFromShareBasedCompensationOperatingActivities_67EB6D43612B070E3024D8E481BD2D42_negatedLabel_en-US" xlink:label="lab_us-gaap_ExcessTaxBenefitFromShareBasedCompensationOperatingActivities_67EB6D43612B070E3024D8E481BD2D42" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Excess tax benefit of stock-based compensation</link:label>
    <link:label id="lab_us-gaap_ExcessTaxBenefitFromShareBasedCompensationOperatingActivities_67EB6D43612B070E3024D8E481BD2D42_label_en-US" xlink:label="lab_us-gaap_ExcessTaxBenefitFromShareBasedCompensationOperatingActivities_67EB6D43612B070E3024D8E481BD2D42" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Excess Tax Benefit from Share-based Compensation, Operating Activities</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ExcessTaxBenefitFromShareBasedCompensationOperatingActivities" xlink:label="loc_us-gaap_ExcessTaxBenefitFromShareBasedCompensationOperatingActivities_67EB6D43612B070E3024D8E481BD2D42" xlink:type="locator" />
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    <link:label id="lab_clh_EmployeeServiceSharebasedCompensationTaxBenefitFromCompensationExpenseNet_E546E02CF800A7D4A6CED8E481BDF5DF_negatedLabel_en-US" xlink:label="lab_clh_EmployeeServiceSharebasedCompensationTaxBenefitFromCompensationExpenseNet_E546E02CF800A7D4A6CED8E481BDF5DF" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Net tax benefit (deficiency) on stock-based awards</link:label>
    <link:label id="lab_clh_EmployeeServiceSharebasedCompensationTaxBenefitFromCompensationExpenseNet_E546E02CF800A7D4A6CED8E481BDF5DF_label_en-US" xlink:label="lab_clh_EmployeeServiceSharebasedCompensationTaxBenefitFromCompensationExpenseNet_E546E02CF800A7D4A6CED8E481BDF5DF" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Employee Service Share-based Compensation, Tax Benefit From Compensation Expense, Net</link:label>
    <link:label id="lab_clh_EmployeeServiceSharebasedCompensationTaxBenefitFromCompensationExpenseNet_E546E02CF800A7D4A6CED8E481BDF5DF_documentation_en-US" xlink:label="lab_clh_EmployeeServiceSharebasedCompensationTaxBenefitFromCompensationExpenseNet_E546E02CF800A7D4A6CED8E481BDF5DF" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Employee Service Share-based Compensation, Tax Benefit From Compensation Expense, Net</link:label>
    <link:loc xlink:href="clh-20171231.xsd#clh_EmployeeServiceSharebasedCompensationTaxBenefitFromCompensationExpenseNet" xlink:label="loc_clh_EmployeeServiceSharebasedCompensationTaxBenefitFromCompensationExpenseNet_E546E02CF800A7D4A6CED8E481BDF5DF" xlink:type="locator" />
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    <link:label id="lab_us-gaap_PaymentsForEnvironmentalLiabilities_1C3FC7C874F30099B0D5D8E481BDED1E_negatedLabel_en-US" xlink:label="lab_us-gaap_PaymentsForEnvironmentalLiabilities_1C3FC7C874F30099B0D5D8E481BDED1E" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Environmental expenditures</link:label>
    <link:label id="lab_us-gaap_PaymentsForEnvironmentalLiabilities_1C3FC7C874F30099B0D5D8E481BDED1E_label_en-US" xlink:label="lab_us-gaap_PaymentsForEnvironmentalLiabilities_1C3FC7C874F30099B0D5D8E481BDED1E" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Payments for Environmental Liabilities</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PaymentsForEnvironmentalLiabilities" xlink:label="loc_us-gaap_PaymentsForEnvironmentalLiabilities_1C3FC7C874F30099B0D5D8E481BDED1E" xlink:type="locator" />
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    <link:label id="lab_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_488D34665461138472BED8E481BD61AC_terseLabel_en-US" xlink:label="lab_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_488D34665461138472BED8E481BD61AC" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Changes in assets and liabilities, net of acquisitions:</link:label>
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    <link:label id="lab_us-gaap_IncreaseDecreaseInAccountsReceivable_E4D1EE7CABDC5CAEB833D8E481BD3755_negatedLabel_en-US" xlink:label="lab_us-gaap_IncreaseDecreaseInAccountsReceivable_E4D1EE7CABDC5CAEB833D8E481BD3755" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Accounts receivable and unbilled accounts receivable</link:label>
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    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncreaseDecreaseInAccountsReceivable" xlink:label="loc_us-gaap_IncreaseDecreaseInAccountsReceivable_E4D1EE7CABDC5CAEB833D8E481BD3755" xlink:type="locator" />
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    <link:label id="lab_us-gaap_IncreaseDecreaseInOtherOperatingAssets_49417CEEB1FF62DCC5EAD8E481BD2523_negatedLabel_en-US" xlink:label="lab_us-gaap_IncreaseDecreaseInOtherOperatingAssets_49417CEEB1FF62DCC5EAD8E481BD2523" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Other current assets</link:label>
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    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncreaseDecreaseInOtherOperatingLiabilities" xlink:label="loc_us-gaap_IncreaseDecreaseInOtherOperatingLiabilities_54C72E90E3A1B303843FD8E481BDE3E1" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncreaseDecreaseInOtherOperatingLiabilities_54C72E90E3A1B303843FD8E481BDE3E1" xlink:to="lab_us-gaap_IncreaseDecreaseInOtherOperatingLiabilities_54C72E90E3A1B303843FD8E481BDE3E1" xlink:type="arc" />
    <link:label id="lab_us-gaap_NetCashProvidedByUsedInOperatingActivities_ACA15355A1FC6BC14421D8E481BD07C7_totalLabel_en-US" xlink:label="lab_us-gaap_NetCashProvidedByUsedInOperatingActivities_ACA15355A1FC6BC14421D8E481BD07C7" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Net cash from operating activities</link:label>
    <link:label id="lab_us-gaap_NetCashProvidedByUsedInOperatingActivities_ACA15355A1FC6BC14421D8E481BD07C7_label_en-US" xlink:label="lab_us-gaap_NetCashProvidedByUsedInOperatingActivities_ACA15355A1FC6BC14421D8E481BD07C7" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Net Cash Provided by (Used in) Operating Activities</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:label="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_ACA15355A1FC6BC14421D8E481BD07C7" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_ACA15355A1FC6BC14421D8E481BD07C7" xlink:to="lab_us-gaap_NetCashProvidedByUsedInOperatingActivities_ACA15355A1FC6BC14421D8E481BD07C7" xlink:type="arc" />
    <link:label id="lab_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_84F7D0B8D9AAB8062C41D8E481BDEEFB_terseLabel_en-US" xlink:label="lab_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_84F7D0B8D9AAB8062C41D8E481BDEEFB" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Cash flows used in investing activities:</link:label>
    <link:label id="lab_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_84F7D0B8D9AAB8062C41D8E481BDEEFB_label_en-US" xlink:label="lab_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_84F7D0B8D9AAB8062C41D8E481BDEEFB" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Net Cash Provided by (Used in) Investing Activities [Abstract]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract" xlink:label="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_84F7D0B8D9AAB8062C41D8E481BDEEFB" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_84F7D0B8D9AAB8062C41D8E481BDEEFB" xlink:to="lab_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_84F7D0B8D9AAB8062C41D8E481BDEEFB" xlink:type="arc" />
    <link:label id="lab_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_71BB1110180C39490BE5D8E481BDFEDE_negatedLabel_en-US" xlink:label="lab_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_71BB1110180C39490BE5D8E481BDFEDE" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Additions to property, plant and equipment</link:label>
    <link:label id="lab_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_71BB1110180C39490BE5D8E481BDFEDE_label_en-US" xlink:label="lab_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_71BB1110180C39490BE5D8E481BDFEDE" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Payments to Acquire Property, Plant, and Equipment</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PaymentsToAcquirePropertyPlantAndEquipment" xlink:label="loc_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_71BB1110180C39490BE5D8E481BDFEDE" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_71BB1110180C39490BE5D8E481BDFEDE" xlink:to="lab_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_71BB1110180C39490BE5D8E481BDFEDE" xlink:type="arc" />
    <link:label id="lab_clh_ProceedsFromSalesOfFixedAssetsAndAssetsHeldForSale_370BD4755D7E61F27409D8E481BEC86E_terseLabel_en-US" xlink:label="lab_clh_ProceedsFromSalesOfFixedAssetsAndAssetsHeldForSale_370BD4755D7E61F27409D8E481BEC86E" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Proceeds from sale and disposal of fixed assets</link:label>
    <link:label id="lab_clh_ProceedsFromSalesOfFixedAssetsAndAssetsHeldForSale_370BD4755D7E61F27409D8E481BEC86E_label_en-US" xlink:label="lab_clh_ProceedsFromSalesOfFixedAssetsAndAssetsHeldForSale_370BD4755D7E61F27409D8E481BEC86E" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Proceeds from Sales of Fixed Assets and Assets Held for Sale</link:label>
    <link:label id="lab_clh_ProceedsFromSalesOfFixedAssetsAndAssetsHeldForSale_370BD4755D7E61F27409D8E481BEC86E_documentation_en-US" xlink:label="lab_clh_ProceedsFromSalesOfFixedAssetsAndAssetsHeldForSale_370BD4755D7E61F27409D8E481BEC86E" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Cash inflow from sale or disposal of property, plant, and equipment and assets held for sale, during the reporting period. This element refers to proceeds from such sale or disposal.</link:label>
    <link:loc xlink:href="clh-20171231.xsd#clh_ProceedsFromSalesOfFixedAssetsAndAssetsHeldForSale" xlink:label="loc_clh_ProceedsFromSalesOfFixedAssetsAndAssetsHeldForSale_370BD4755D7E61F27409D8E481BEC86E" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_clh_ProceedsFromSalesOfFixedAssetsAndAssetsHeldForSale_370BD4755D7E61F27409D8E481BEC86E" xlink:to="lab_clh_ProceedsFromSalesOfFixedAssetsAndAssetsHeldForSale_370BD4755D7E61F27409D8E481BEC86E" xlink:type="arc" />
    <link:label id="lab_us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired_E3F4479303006102DACDD8E481BE3BA7_negatedLabel_en-US" xlink:label="lab_us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired_E3F4479303006102DACDD8E481BE3BA7" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Acquisitions, net of cash acquired</link:label>
    <link:label id="lab_us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired_E3F4479303006102DACDD8E481BE3BA7_label_en-US" xlink:label="lab_us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired_E3F4479303006102DACDD8E481BE3BA7" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Payments to Acquire Businesses, Net of Cash Acquired</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired" xlink:label="loc_us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired_E3F4479303006102DACDD8E481BE3BA7" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired_E3F4479303006102DACDD8E481BE3BA7" xlink:to="lab_us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired_E3F4479303006102DACDD8E481BE3BA7" xlink:type="arc" />
    <link:label id="lab_us-gaap_PaymentsToAcquireIntangibleAssets_A6F2BC0B41A624A347E8D8E481BE2573_negatedLabel_en-US" xlink:label="lab_us-gaap_PaymentsToAcquireIntangibleAssets_A6F2BC0B41A624A347E8D8E481BE2573" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Additions to intangible assets including costs to obtain or renew permits</link:label>
    <link:label id="lab_us-gaap_PaymentsToAcquireIntangibleAssets_A6F2BC0B41A624A347E8D8E481BE2573_label_en-US" xlink:label="lab_us-gaap_PaymentsToAcquireIntangibleAssets_A6F2BC0B41A624A347E8D8E481BE2573" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Payments to Acquire Intangible Assets</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PaymentsToAcquireIntangibleAssets" xlink:label="loc_us-gaap_PaymentsToAcquireIntangibleAssets_A6F2BC0B41A624A347E8D8E481BE2573" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PaymentsToAcquireIntangibleAssets_A6F2BC0B41A624A347E8D8E481BE2573" xlink:to="lab_us-gaap_PaymentsToAcquireIntangibleAssets_A6F2BC0B41A624A347E8D8E481BE2573" xlink:type="arc" />
    <link:label id="lab_us-gaap_PaymentsToAcquireAvailableForSaleSecurities_ABD17B581EAD72FDDAD8D8E481BE5DF8_negatedLabel_en-US" xlink:label="lab_us-gaap_PaymentsToAcquireAvailableForSaleSecurities_ABD17B581EAD72FDDAD8D8E481BE5DF8" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Purchases of available-for-sale securities</link:label>
    <link:label id="lab_us-gaap_PaymentsToAcquireAvailableForSaleSecurities_ABD17B581EAD72FDDAD8D8E481BE5DF8_label_en-US" xlink:label="lab_us-gaap_PaymentsToAcquireAvailableForSaleSecurities_ABD17B581EAD72FDDAD8D8E481BE5DF8" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Payments to Acquire Available-for-sale Securities</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PaymentsToAcquireAvailableForSaleSecurities" xlink:label="loc_us-gaap_PaymentsToAcquireAvailableForSaleSecurities_ABD17B581EAD72FDDAD8D8E481BE5DF8" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PaymentsToAcquireAvailableForSaleSecurities_ABD17B581EAD72FDDAD8D8E481BE5DF8" xlink:to="lab_us-gaap_PaymentsToAcquireAvailableForSaleSecurities_ABD17B581EAD72FDDAD8D8E481BE5DF8" xlink:type="arc" />
    <link:label id="lab_us-gaap_ProceedsFromDivestitureOfBusinesses_229001CC7D9657369B21D8E481BECB4F_terseLabel_en-US" xlink:label="lab_us-gaap_ProceedsFromDivestitureOfBusinesses_229001CC7D9657369B21D8E481BECB4F" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Proceeds on sale of businesses, net of transactional costs</link:label>
    <link:label id="lab_us-gaap_ProceedsFromDivestitureOfBusinesses_229001CC7D9657369B21D8E481BECB4F_label_en-US" xlink:label="lab_us-gaap_ProceedsFromDivestitureOfBusinesses_229001CC7D9657369B21D8E481BECB4F" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Proceeds from Divestiture of Businesses</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ProceedsFromDivestitureOfBusinesses" xlink:label="loc_us-gaap_ProceedsFromDivestitureOfBusinesses_229001CC7D9657369B21D8E481BECB4F" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ProceedsFromDivestitureOfBusinesses_229001CC7D9657369B21D8E481BECB4F" xlink:to="lab_us-gaap_ProceedsFromDivestitureOfBusinesses_229001CC7D9657369B21D8E481BECB4F" xlink:type="arc" />
    <link:label id="lab_us-gaap_ProceedsFromSaleOfLongtermInvestments_18A6209655450D522FDDD8E481BE1B6F_verboseLabel_en-US" xlink:label="lab_us-gaap_ProceedsFromSaleOfLongtermInvestments_18A6209655450D522FDDD8E481BE1B6F" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Proceeds from sale of long-term investments</link:label>
    <link:label id="lab_us-gaap_ProceedsFromSaleOfLongtermInvestments_18A6209655450D522FDDD8E481BE1B6F_label_en-US" xlink:label="lab_us-gaap_ProceedsFromSaleOfLongtermInvestments_18A6209655450D522FDDD8E481BE1B6F" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Proceeds from Sale of Long-term Investments</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ProceedsFromSaleOfLongtermInvestments" xlink:label="loc_us-gaap_ProceedsFromSaleOfLongtermInvestments_18A6209655450D522FDDD8E481BE1B6F" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ProceedsFromSaleOfLongtermInvestments_18A6209655450D522FDDD8E481BE1B6F" xlink:to="lab_us-gaap_ProceedsFromSaleOfLongtermInvestments_18A6209655450D522FDDD8E481BE1B6F" xlink:type="arc" />
    <link:label id="lab_us-gaap_NetCashProvidedByUsedInInvestingActivities_66BB7586195D84837711D8E481BEA77B_totalLabel_en-US" xlink:label="lab_us-gaap_NetCashProvidedByUsedInInvestingActivities_66BB7586195D84837711D8E481BEA77B" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Net cash used in investing activities</link:label>
    <link:label id="lab_us-gaap_NetCashProvidedByUsedInInvestingActivities_66BB7586195D84837711D8E481BEA77B_label_en-US" xlink:label="lab_us-gaap_NetCashProvidedByUsedInInvestingActivities_66BB7586195D84837711D8E481BEA77B" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Net Cash Provided by (Used in) Investing Activities</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:label="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_66BB7586195D84837711D8E481BEA77B" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_66BB7586195D84837711D8E481BEA77B" xlink:to="lab_us-gaap_NetCashProvidedByUsedInInvestingActivities_66BB7586195D84837711D8E481BEA77B" xlink:type="arc" />
    <link:label id="lab_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_B4166ECE2AB8AB7E2121D8E481BEF67E_terseLabel_en-US" xlink:label="lab_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_B4166ECE2AB8AB7E2121D8E481BEF67E" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Cash flows (used in) from financing activities:</link:label>
    <link:label id="lab_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_B4166ECE2AB8AB7E2121D8E481BEF67E_label_en-US" xlink:label="lab_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_B4166ECE2AB8AB7E2121D8E481BEF67E" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Net Cash Provided by (Used in) Financing Activities [Abstract]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract" xlink:label="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_B4166ECE2AB8AB7E2121D8E481BEF67E" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_B4166ECE2AB8AB7E2121D8E481BEF67E" xlink:to="lab_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_B4166ECE2AB8AB7E2121D8E481BEF67E" xlink:type="arc" />
    <link:label id="lab_us-gaap_IncreaseDecreaseInOutstandingChecksFinancingActivities_4B706793DD7C1BD706E2D8E481BEB951_terseLabel_en-US" xlink:label="lab_us-gaap_IncreaseDecreaseInOutstandingChecksFinancingActivities_4B706793DD7C1BD706E2D8E481BEB951" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Change in uncashed checks</link:label>
    <link:label id="lab_us-gaap_IncreaseDecreaseInOutstandingChecksFinancingActivities_4B706793DD7C1BD706E2D8E481BEB951_label_en-US" xlink:label="lab_us-gaap_IncreaseDecreaseInOutstandingChecksFinancingActivities_4B706793DD7C1BD706E2D8E481BEB951" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Increase (Decrease) in Outstanding Checks, Financing Activities</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncreaseDecreaseInOutstandingChecksFinancingActivities" xlink:label="loc_us-gaap_IncreaseDecreaseInOutstandingChecksFinancingActivities_4B706793DD7C1BD706E2D8E481BEB951" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncreaseDecreaseInOutstandingChecksFinancingActivities_4B706793DD7C1BD706E2D8E481BEB951" xlink:to="lab_us-gaap_IncreaseDecreaseInOutstandingChecksFinancingActivities_4B706793DD7C1BD706E2D8E481BEB951" xlink:type="arc" />
    <link:label id="lab_us-gaap_ProceedsFromStockOptionsExercised_980346735EC298BAC28CD8E481BE998F_terseLabel_en-US" xlink:label="lab_us-gaap_ProceedsFromStockOptionsExercised_980346735EC298BAC28CD8E481BE998F" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Proceeds from exercise of stock options</link:label>
    <link:label id="lab_us-gaap_ProceedsFromStockOptionsExercised_980346735EC298BAC28CD8E481BE998F_label_en-US" xlink:label="lab_us-gaap_ProceedsFromStockOptionsExercised_980346735EC298BAC28CD8E481BE998F" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Proceeds from Stock Options Exercised</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ProceedsFromStockOptionsExercised" xlink:label="loc_us-gaap_ProceedsFromStockOptionsExercised_980346735EC298BAC28CD8E481BE998F" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ProceedsFromStockOptionsExercised_980346735EC298BAC28CD8E481BE998F" xlink:to="lab_us-gaap_ProceedsFromStockOptionsExercised_980346735EC298BAC28CD8E481BE998F" xlink:type="arc" />
    <link:label id="lab_us-gaap_PaymentsRelatedToTaxWithholdingForShareBasedCompensation_D069625B51A5540EE471D8E481BE4700_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_PaymentsRelatedToTaxWithholdingForShareBasedCompensation_D069625B51A5540EE471D8E481BE4700" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Tax payments related to withholdings on vested restricted stock</link:label>
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    <link:label id="lab_us-gaap_ExcessTaxBenefitFromShareBasedCompensationFinancingActivities_AEE9A78EAB81B97A28B0D8E481BE67C9_terseLabel_en-US" xlink:label="lab_us-gaap_ExcessTaxBenefitFromShareBasedCompensationFinancingActivities_AEE9A78EAB81B97A28B0D8E481BE67C9" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Excess tax benefit of stock-based compensation</link:label>
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    <link:label id="lab_clh_RepaymentOfCapitalLeaseObligation_4DB1159CDECA50466EDCD8E481BE8523_negatedLabel_en-US" xlink:label="lab_clh_RepaymentOfCapitalLeaseObligation_4DB1159CDECA50466EDCD8E481BE8523" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Payments on capital leases</link:label>
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    <link:label id="lab_us-gaap_PaymentsOfDebtExtinguishmentCosts_0EEBEF52F1A84FB109EDD8E481BE11B5_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_PaymentsOfDebtExtinguishmentCosts_0EEBEF52F1A84FB109EDD8E481BE11B5" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Premiums paid on early extinguishment of debt</link:label>
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    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PaymentsOfDebtExtinguishmentCosts" xlink:label="loc_us-gaap_PaymentsOfDebtExtinguishmentCosts_0EEBEF52F1A84FB109EDD8E481BE11B5" xlink:type="locator" />
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    <link:label id="lab_us-gaap_RepaymentsOfLongTermDebt_90596DC1DA7B101629CDD8E481BEE3A0_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_RepaymentsOfLongTermDebt_90596DC1DA7B101629CDD8E481BEE3A0" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Principal payment on debt</link:label>
    <link:label id="lab_us-gaap_RepaymentsOfLongTermDebt_90596DC1DA7B101629CDD8E481BEE3A0_label_en-US" xlink:label="lab_us-gaap_RepaymentsOfLongTermDebt_90596DC1DA7B101629CDD8E481BEE3A0" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Repayments of Long-term Debt</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RepaymentsOfLongTermDebt" xlink:label="loc_us-gaap_RepaymentsOfLongTermDebt_90596DC1DA7B101629CDD8E481BEE3A0" xlink:type="locator" />
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    <link:label id="lab_us-gaap_ProceedsFromIssuanceOfSeniorLongTermDebt_BA70A292BFDF69752041D8E481BEE445_terseLabel_en-US" xlink:label="lab_us-gaap_ProceedsFromIssuanceOfSeniorLongTermDebt_BA70A292BFDF69752041D8E481BEE445" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Issuance of senior secured notes, net of discount</link:label>
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    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ProceedsFromIssuanceOfLongTermDebt" xlink:label="loc_us-gaap_ProceedsFromIssuanceOfLongTermDebt_5005D840FC88AEC9EC6CD8E481BFBDD0" xlink:type="locator" />
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    <link:label id="lab_us-gaap_NetCashProvidedByUsedInFinancingActivities_AB68F499512A21D028C6D8E481BF5FBA_totalLabel_en-US" xlink:label="lab_us-gaap_NetCashProvidedByUsedInFinancingActivities_AB68F499512A21D028C6D8E481BF5FBA" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Net cash (used in) from financing activities</link:label>
    <link:label id="lab_us-gaap_NetCashProvidedByUsedInFinancingActivities_AB68F499512A21D028C6D8E481BF5FBA_label_en-US" xlink:label="lab_us-gaap_NetCashProvidedByUsedInFinancingActivities_AB68F499512A21D028C6D8E481BF5FBA" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Net Cash Provided by (Used in) Financing Activities</link:label>
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    <link:label id="lab_us-gaap_EffectOfExchangeRateOnCashAndCashEquivalents_06605D0C16E97EFFB6FFD8E481BF0712_terseLabel_en-US" xlink:label="lab_us-gaap_EffectOfExchangeRateOnCashAndCashEquivalents_06605D0C16E97EFFB6FFD8E481BF0712" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Effect of exchange rate change on cash</link:label>
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    <link:label id="lab_us-gaap_AssetsFairValueDisclosure_4CE7DB79FE70B57C14FFA01318A6DA64_terseLabel_en-US" xlink:label="lab_us-gaap_AssetsFairValueDisclosure_4CE7DB79FE70B57C14FFA01318A6DA64" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Total financial assets</link:label>
    <link:label id="lab_us-gaap_AssetsFairValueDisclosure_4CE7DB79FE70B57C14FFA01318A6DA64_label_en-US" xlink:label="lab_us-gaap_AssetsFairValueDisclosure_4CE7DB79FE70B57C14FFA01318A6DA64" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Assets, Fair Value Disclosure</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AssetsFairValueDisclosure" xlink:label="loc_us-gaap_AssetsFairValueDisclosure_4CE7DB79FE70B57C14FFA01318A6DA64" xlink:type="locator" />
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    <link:label id="lab_us-gaap_DebtDisclosureTextBlock_75FCCCF55F17106D67B432A718629879_terseLabel_en-US" xlink:label="lab_us-gaap_DebtDisclosureTextBlock_75FCCCF55F17106D67B432A718629879" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">FINANCING ARRANGEMENTS</link:label>
    <link:label id="lab_us-gaap_DebtDisclosureTextBlock_75FCCCF55F17106D67B432A718629879_label_en-US" xlink:label="lab_us-gaap_DebtDisclosureTextBlock_75FCCCF55F17106D67B432A718629879" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Debt Disclosure [Text Block]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtDisclosureTextBlock" xlink:label="loc_us-gaap_DebtDisclosureTextBlock_75FCCCF55F17106D67B432A718629879" xlink:type="locator" />
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    <link:label id="lab_us-gaap_ScheduleOfAccruedLiabilitiesTableTextBlock_8093382FC9809AECE39F32A7159AA295_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfAccruedLiabilitiesTableTextBlock_8093382FC9809AECE39F32A7159AA295" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Accrued Expenses</link:label>
    <link:label id="lab_us-gaap_ScheduleOfAccruedLiabilitiesTableTextBlock_8093382FC9809AECE39F32A7159AA295_label_en-US" xlink:label="lab_us-gaap_ScheduleOfAccruedLiabilitiesTableTextBlock_8093382FC9809AECE39F32A7159AA295" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Schedule of Accrued Liabilities [Table Text Block]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfAccruedLiabilitiesTableTextBlock" xlink:label="loc_us-gaap_ScheduleOfAccruedLiabilitiesTableTextBlock_8093382FC9809AECE39F32A7159AA295" xlink:type="locator" />
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    <link:label id="lab_us-gaap_EnvironmentalPropertySaleDisposalOrAbandonmentCostsAbstract_DEA5B5CFE39762A2A22D39D28464D967_terseLabel_en-US" xlink:label="lab_us-gaap_EnvironmentalPropertySaleDisposalOrAbandonmentCostsAbstract_DEA5B5CFE39762A2A22D39D28464D967" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Environmental Property Sale, Disposal or Abandonment Costs</link:label>
    <link:label id="lab_us-gaap_EnvironmentalPropertySaleDisposalOrAbandonmentCostsAbstract_DEA5B5CFE39762A2A22D39D28464D967_label_en-US" xlink:label="lab_us-gaap_EnvironmentalPropertySaleDisposalOrAbandonmentCostsAbstract_DEA5B5CFE39762A2A22D39D28464D967" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Environmental Property Sale, Disposal or Abandonment Costs [Abstract]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EnvironmentalPropertySaleDisposalOrAbandonmentCostsAbstract" xlink:label="loc_us-gaap_EnvironmentalPropertySaleDisposalOrAbandonmentCostsAbstract_DEA5B5CFE39762A2A22D39D28464D967" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EnvironmentalPropertySaleDisposalOrAbandonmentCostsAbstract_DEA5B5CFE39762A2A22D39D28464D967" xlink:to="lab_us-gaap_EnvironmentalPropertySaleDisposalOrAbandonmentCostsAbstract_DEA5B5CFE39762A2A22D39D28464D967" xlink:type="arc" />
    <link:label id="lab_clh_AnticipatedPaymentForAssetRetirementObligationsYearOne_8897B3C72530F7668B5239D284640BED_terseLabel_en-US" xlink:label="lab_clh_AnticipatedPaymentForAssetRetirementObligationsYearOne_8897B3C72530F7668B5239D284640BED" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2018</link:label>
    <link:label id="lab_clh_AnticipatedPaymentForAssetRetirementObligationsYearOne_8897B3C72530F7668B5239D284640BED_label_en-US" xlink:label="lab_clh_AnticipatedPaymentForAssetRetirementObligationsYearOne_8897B3C72530F7668B5239D284640BED" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Anticipated Payment for Asset Retirement Obligations year One</link:label>
    <link:label id="lab_clh_AnticipatedPaymentForAssetRetirementObligationsYearOne_8897B3C72530F7668B5239D284640BED_documentation_en-US" xlink:label="lab_clh_AnticipatedPaymentForAssetRetirementObligationsYearOne_8897B3C72530F7668B5239D284640BED" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Anticipated Payment for Asset Retirement Obligations year One</link:label>
    <link:loc xlink:href="clh-20171231.xsd#clh_AnticipatedPaymentForAssetRetirementObligationsYearOne" xlink:label="loc_clh_AnticipatedPaymentForAssetRetirementObligationsYearOne_8897B3C72530F7668B5239D284640BED" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_clh_AnticipatedPaymentForAssetRetirementObligationsYearOne_8897B3C72530F7668B5239D284640BED" xlink:to="lab_clh_AnticipatedPaymentForAssetRetirementObligationsYearOne_8897B3C72530F7668B5239D284640BED" xlink:type="arc" />
    <link:label id="lab_clh_AnticipatedPaymentForAssetRetirementObligationsYearTwo_ADF8F87B6EF2D218973639D284646111_terseLabel_en-US" xlink:label="lab_clh_AnticipatedPaymentForAssetRetirementObligationsYearTwo_ADF8F87B6EF2D218973639D284646111" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2019</link:label>
    <link:label id="lab_clh_AnticipatedPaymentForAssetRetirementObligationsYearTwo_ADF8F87B6EF2D218973639D284646111_label_en-US" xlink:label="lab_clh_AnticipatedPaymentForAssetRetirementObligationsYearTwo_ADF8F87B6EF2D218973639D284646111" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Anticipated Payment for Asset Retirement Obligations year Two</link:label>
    <link:label id="lab_clh_AnticipatedPaymentForAssetRetirementObligationsYearTwo_ADF8F87B6EF2D218973639D284646111_documentation_en-US" xlink:label="lab_clh_AnticipatedPaymentForAssetRetirementObligationsYearTwo_ADF8F87B6EF2D218973639D284646111" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Anticipated Payment for Asset Retirement Obligations year Two</link:label>
    <link:loc xlink:href="clh-20171231.xsd#clh_AnticipatedPaymentForAssetRetirementObligationsYearTwo" xlink:label="loc_clh_AnticipatedPaymentForAssetRetirementObligationsYearTwo_ADF8F87B6EF2D218973639D284646111" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_clh_AnticipatedPaymentForAssetRetirementObligationsYearTwo_ADF8F87B6EF2D218973639D284646111" xlink:to="lab_clh_AnticipatedPaymentForAssetRetirementObligationsYearTwo_ADF8F87B6EF2D218973639D284646111" xlink:type="arc" />
    <link:label id="lab_clh_AnticipatedPaymentForAssetRetirementObligationsYearThree_FEC3681AE6C6486FAAC539D28465D79B_terseLabel_en-US" xlink:label="lab_clh_AnticipatedPaymentForAssetRetirementObligationsYearThree_FEC3681AE6C6486FAAC539D28465D79B" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2020</link:label>
    <link:label id="lab_clh_AnticipatedPaymentForAssetRetirementObligationsYearThree_FEC3681AE6C6486FAAC539D28465D79B_label_en-US" xlink:label="lab_clh_AnticipatedPaymentForAssetRetirementObligationsYearThree_FEC3681AE6C6486FAAC539D28465D79B" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Anticipated Payment for Asset Retirement Obligations year Three</link:label>
    <link:label id="lab_clh_AnticipatedPaymentForAssetRetirementObligationsYearThree_FEC3681AE6C6486FAAC539D28465D79B_documentation_en-US" xlink:label="lab_clh_AnticipatedPaymentForAssetRetirementObligationsYearThree_FEC3681AE6C6486FAAC539D28465D79B" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Anticipated Payment for Asset Retirement Obligations year Three</link:label>
    <link:loc xlink:href="clh-20171231.xsd#clh_AnticipatedPaymentForAssetRetirementObligationsYearThree" xlink:label="loc_clh_AnticipatedPaymentForAssetRetirementObligationsYearThree_FEC3681AE6C6486FAAC539D28465D79B" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_clh_AnticipatedPaymentForAssetRetirementObligationsYearThree_FEC3681AE6C6486FAAC539D28465D79B" xlink:to="lab_clh_AnticipatedPaymentForAssetRetirementObligationsYearThree_FEC3681AE6C6486FAAC539D28465D79B" xlink:type="arc" />
    <link:label id="lab_clh_AnticipatedPaymentForAssetRetirementObligationsYearFour_F9F6E7755AFD363A404E39D284656616_terseLabel_en-US" xlink:label="lab_clh_AnticipatedPaymentForAssetRetirementObligationsYearFour_F9F6E7755AFD363A404E39D284656616" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2021</link:label>
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    <link:label id="lab_clh_AnticipatedPaymentForAssetRetirementObligationsYearFour_F9F6E7755AFD363A404E39D284656616_documentation_en-US" xlink:label="lab_clh_AnticipatedPaymentForAssetRetirementObligationsYearFour_F9F6E7755AFD363A404E39D284656616" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Anticipated Payment for Asset Retirement Obligations year Four</link:label>
    <link:loc xlink:href="clh-20171231.xsd#clh_AnticipatedPaymentForAssetRetirementObligationsYearFour" xlink:label="loc_clh_AnticipatedPaymentForAssetRetirementObligationsYearFour_F9F6E7755AFD363A404E39D284656616" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_clh_AnticipatedPaymentForAssetRetirementObligationsYearFour_F9F6E7755AFD363A404E39D284656616" xlink:to="lab_clh_AnticipatedPaymentForAssetRetirementObligationsYearFour_F9F6E7755AFD363A404E39D284656616" xlink:type="arc" />
    <link:label id="lab_clh_AnticipatedPaymentForAssetRetirementObligationsYearFive_919E40E42716A626F53D39D28465310D_terseLabel_en-US" xlink:label="lab_clh_AnticipatedPaymentForAssetRetirementObligationsYearFive_919E40E42716A626F53D39D28465310D" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2022</link:label>
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    <link:label id="lab_clh_AnticipatedPaymentForAssetRetirementObligationsYearFive_919E40E42716A626F53D39D28465310D_documentation_en-US" xlink:label="lab_clh_AnticipatedPaymentForAssetRetirementObligationsYearFive_919E40E42716A626F53D39D28465310D" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Anticipated Payment for Asset Retirement Obligations year Five</link:label>
    <link:loc xlink:href="clh-20171231.xsd#clh_AnticipatedPaymentForAssetRetirementObligationsYearFive" xlink:label="loc_clh_AnticipatedPaymentForAssetRetirementObligationsYearFive_919E40E42716A626F53D39D28465310D" xlink:type="locator" />
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    <link:label id="lab_clh_AnticipatedPaymentForAssetRetirementObligationsAfterYearFive_C40A015E033DEF88AFB139D28465C435_terseLabel_en-US" xlink:label="lab_clh_AnticipatedPaymentForAssetRetirementObligationsAfterYearFive_C40A015E033DEF88AFB139D28465C435" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Thereafter</link:label>
    <link:label id="lab_clh_AnticipatedPaymentForAssetRetirementObligationsAfterYearFive_C40A015E033DEF88AFB139D28465C435_label_en-US" xlink:label="lab_clh_AnticipatedPaymentForAssetRetirementObligationsAfterYearFive_C40A015E033DEF88AFB139D28465C435" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Anticipated Payment for Asset Retirement Obligations, After Year Five</link:label>
    <link:label id="lab_clh_AnticipatedPaymentForAssetRetirementObligationsAfterYearFive_C40A015E033DEF88AFB139D28465C435_documentation_en-US" xlink:label="lab_clh_AnticipatedPaymentForAssetRetirementObligationsAfterYearFive_C40A015E033DEF88AFB139D28465C435" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Anticipated Payment for Asset Retirement Obligations, After Year Five</link:label>
    <link:loc xlink:href="clh-20171231.xsd#clh_AnticipatedPaymentForAssetRetirementObligationsAfterYearFive" xlink:label="loc_clh_AnticipatedPaymentForAssetRetirementObligationsAfterYearFive_C40A015E033DEF88AFB139D28465C435" xlink:type="locator" />
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    <link:label id="lab_clh_UndiscountedClosureAndPostClosureLiabilities_9E8DD57FA152C4A5770D39D28465281F_totalLabel_en-US" xlink:label="lab_clh_UndiscountedClosureAndPostClosureLiabilities_9E8DD57FA152C4A5770D39D28465281F" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Undiscounted closure and post-closure liabilities</link:label>
    <link:label id="lab_clh_UndiscountedClosureAndPostClosureLiabilities_9E8DD57FA152C4A5770D39D28465281F_label_en-US" xlink:label="lab_clh_UndiscountedClosureAndPostClosureLiabilities_9E8DD57FA152C4A5770D39D28465281F" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Undiscounted Closure and Post-Closure Liabilities</link:label>
    <link:label id="lab_clh_UndiscountedClosureAndPostClosureLiabilities_9E8DD57FA152C4A5770D39D28465281F_documentation_en-US" xlink:label="lab_clh_UndiscountedClosureAndPostClosureLiabilities_9E8DD57FA152C4A5770D39D28465281F" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Undiscounted Closure and Post-Closure Liabilities</link:label>
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    <link:label id="lab_clh_DiscountReserves_8F01C9EE384BF2ED8F7739D284654817_negatedTerseLabel_en-US" xlink:label="lab_clh_DiscountReserves_8F01C9EE384BF2ED8F7739D284654817" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Less: Discount at credit-adjusted risk-free rate</link:label>
    <link:label id="lab_clh_DiscountReserves_8F01C9EE384BF2ED8F7739D284654817_label_en-US" xlink:label="lab_clh_DiscountReserves_8F01C9EE384BF2ED8F7739D284654817" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Discount Reserves</link:label>
    <link:label id="lab_clh_DiscountReserves_8F01C9EE384BF2ED8F7739D284654817_documentation_en-US" xlink:label="lab_clh_DiscountReserves_8F01C9EE384BF2ED8F7739D284654817" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Discount Reserves</link:label>
    <link:loc xlink:href="clh-20171231.xsd#clh_DiscountReserves" xlink:label="loc_clh_DiscountReserves_8F01C9EE384BF2ED8F7739D284654817" xlink:type="locator" />
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    <link:label id="lab_clh_ReservesToBeProvidedOverRemainingSiteLives_4E06AE2CA1BC3DC90F8939D28465F6B5_negatedTerseLabel_en-US" xlink:label="lab_clh_ReservesToBeProvidedOverRemainingSiteLives_4E06AE2CA1BC3DC90F8939D28465F6B5" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Less: Undiscounted estimated closure and post-closure liabilities relating to airspace not yet consumed</link:label>
    <link:label id="lab_clh_ReservesToBeProvidedOverRemainingSiteLives_4E06AE2CA1BC3DC90F8939D28465F6B5_label_en-US" xlink:label="lab_clh_ReservesToBeProvidedOverRemainingSiteLives_4E06AE2CA1BC3DC90F8939D28465F6B5" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Reserves to be Provided Over Remaining Site Lives</link:label>
    <link:label id="lab_clh_ReservesToBeProvidedOverRemainingSiteLives_4E06AE2CA1BC3DC90F8939D28465F6B5_documentation_en-US" xlink:label="lab_clh_ReservesToBeProvidedOverRemainingSiteLives_4E06AE2CA1BC3DC90F8939D28465F6B5" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Reserves to be Provided Over Remaining Site Lives</link:label>
    <link:loc xlink:href="clh-20171231.xsd#clh_ReservesToBeProvidedOverRemainingSiteLives" xlink:label="loc_clh_ReservesToBeProvidedOverRemainingSiteLives_4E06AE2CA1BC3DC90F8939D28465F6B5" xlink:type="locator" />
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    <link:label id="lab_us-gaap_AssetRetirementObligation_3AA622E63EFE2610157039D28465AED5_totalLabel_en-US" xlink:label="lab_us-gaap_AssetRetirementObligation_3AA622E63EFE2610157039D28465AED5" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Present value of closure and post-closure liabilities</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AssetRetirementObligation" xlink:label="loc_us-gaap_AssetRetirementObligation_3AA622E63EFE2610157039D28465AED5" xlink:type="locator" />
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    <link:label id="lab_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_BA9A9B71E203CFE0B5DA32A7180E94A0_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_BA9A9B71E203CFE0B5DA32A7180E94A0" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Schedule of Property, Plant and Equipment [Table]</link:label>
    <link:label id="lab_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_BA9A9B71E203CFE0B5DA32A7180E94A0_label_en-US" xlink:label="lab_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_BA9A9B71E203CFE0B5DA32A7180E94A0" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Property, Plant and Equipment [Table]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfPropertyPlantAndEquipmentTable" xlink:label="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_BA9A9B71E203CFE0B5DA32A7180E94A0" xlink:type="locator" />
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    <link:label id="lab_us-gaap_WeightedAverageMember_5E0F23D6A70A2857F33B32A7180EAF0E_terseLabel_en-US" xlink:label="lab_us-gaap_WeightedAverageMember_5E0F23D6A70A2857F33B32A7180EAF0E" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Weighted average</link:label>
    <link:label id="lab_us-gaap_WeightedAverageMember_5E0F23D6A70A2857F33B32A7180EAF0E_label_en-US" xlink:label="lab_us-gaap_WeightedAverageMember_5E0F23D6A70A2857F33B32A7180EAF0E" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Weighted Average [Member]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_WeightedAverageMember" xlink:label="loc_us-gaap_WeightedAverageMember_5E0F23D6A70A2857F33B32A7180EAF0E" xlink:type="locator" />
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    <link:label id="lab_us-gaap_PropertyPlantAndEquipmentByTypeAxis_80712BE23AF19C60B7B632A7180E8E35_terseLabel_en-US" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentByTypeAxis_80712BE23AF19C60B7B632A7180E8E35" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Property, Plant and Equipment by Type [Axis]</link:label>
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    <link:label id="lab_us-gaap_PropertyPlantAndEquipmentTypeDomain_531DB85AFF373DD6ADE132A7180E84D8_label_en-US" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentTypeDomain_531DB85AFF373DD6ADE132A7180E84D8" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Property, Plant and Equipment, Type [Domain]</link:label>
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    <link:label id="lab_us-gaap_BuildingMember_954A224D63D7241C0F0E32A7180E9F99_terseLabel_en-US" xlink:label="lab_us-gaap_BuildingMember_954A224D63D7241C0F0E32A7180E9F99" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Buildings</link:label>
    <link:label id="lab_us-gaap_BuildingMember_954A224D63D7241C0F0E32A7180E9F99_label_en-US" xlink:label="lab_us-gaap_BuildingMember_954A224D63D7241C0F0E32A7180E9F99" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Building [Member]</link:label>
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    <link:label id="lab_us-gaap_LandBuildingsAndImprovementsMember_DFA058FA2FB7653F51FD32A7180EDFED_terseLabel_en-US" xlink:label="lab_us-gaap_LandBuildingsAndImprovementsMember_DFA058FA2FB7653F51FD32A7180EDFED" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Leasehold and building improvements</link:label>
    <link:label id="lab_us-gaap_LandBuildingsAndImprovementsMember_DFA058FA2FB7653F51FD32A7180EDFED_label_en-US" xlink:label="lab_us-gaap_LandBuildingsAndImprovementsMember_DFA058FA2FB7653F51FD32A7180EDFED" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Land, Buildings and Improvements [Member]</link:label>
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    <link:label id="lab_clh_CampEquipmentMember_E5299B1869F7F422E11432A7180F3D10_terseLabel_en-US" xlink:label="lab_clh_CampEquipmentMember_E5299B1869F7F422E11432A7180F3D10" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Camp equipment</link:label>
    <link:label id="lab_clh_CampEquipmentMember_E5299B1869F7F422E11432A7180F3D10_label_en-US" xlink:label="lab_clh_CampEquipmentMember_E5299B1869F7F422E11432A7180F3D10" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Camp Equipment [Member]</link:label>
    <link:label id="lab_clh_CampEquipmentMember_E5299B1869F7F422E11432A7180F3D10_documentation_en-US" xlink:label="lab_clh_CampEquipmentMember_E5299B1869F7F422E11432A7180F3D10" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the industrial lodging facilities that are utilized in the entity's Industrial Services segment to provide lodging services to companies in the refinery and petrochemical industries.</link:label>
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    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_clh_CampEquipmentMember_E5299B1869F7F422E11432A7180F3D10" xlink:to="lab_clh_CampEquipmentMember_E5299B1869F7F422E11432A7180F3D10" xlink:type="arc" />
    <link:label id="lab_us-gaap_VehiclesMember_2561A4E0B62C8D0A659632A7180F41FA_terseLabel_en-US" xlink:label="lab_us-gaap_VehiclesMember_2561A4E0B62C8D0A659632A7180F41FA" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Vehicles</link:label>
    <link:label id="lab_us-gaap_VehiclesMember_2561A4E0B62C8D0A659632A7180F41FA_label_en-US" xlink:label="lab_us-gaap_VehiclesMember_2561A4E0B62C8D0A659632A7180F41FA" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Vehicles [Member]</link:label>
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    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_VehiclesMember_2561A4E0B62C8D0A659632A7180F41FA" xlink:to="lab_us-gaap_VehiclesMember_2561A4E0B62C8D0A659632A7180F41FA" xlink:type="arc" />
    <link:label id="lab_us-gaap_ComputerEquipmentMember_0DC0E71999B0F5E1A4D832A7180FE4C2_terseLabel_en-US" xlink:label="lab_us-gaap_ComputerEquipmentMember_0DC0E71999B0F5E1A4D832A7180FE4C2" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Capitalized software and computer equipment</link:label>
    <link:label id="lab_us-gaap_ComputerEquipmentMember_0DC0E71999B0F5E1A4D832A7180FE4C2_label_en-US" xlink:label="lab_us-gaap_ComputerEquipmentMember_0DC0E71999B0F5E1A4D832A7180FE4C2" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Computer Equipment [Member]</link:label>
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    <link:label id="lab_clh_SolarEquipmentMember_920BF11A1D0C3465381132A7180F4EE9_terseLabel_en-US" xlink:label="lab_clh_SolarEquipmentMember_920BF11A1D0C3465381132A7180F4EE9" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Solar equipment</link:label>
    <link:label id="lab_clh_SolarEquipmentMember_920BF11A1D0C3465381132A7180F4EE9_label_en-US" xlink:label="lab_clh_SolarEquipmentMember_920BF11A1D0C3465381132A7180F4EE9" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Solar Equipment [Member]</link:label>
    <link:label id="lab_clh_SolarEquipmentMember_920BF11A1D0C3465381132A7180F4EE9_documentation_en-US" xlink:label="lab_clh_SolarEquipmentMember_920BF11A1D0C3465381132A7180F4EE9" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the long-lived, depreciable asset which consists of a solar array that is used to provide electric power for a continuously operating groundwater decontamination pump and treatment system at a closed and capped landfill.</link:label>
    <link:loc xlink:href="clh-20171231.xsd#clh_SolarEquipmentMember" xlink:label="loc_clh_SolarEquipmentMember_920BF11A1D0C3465381132A7180F4EE9" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_clh_SolarEquipmentMember_920BF11A1D0C3465381132A7180F4EE9" xlink:to="lab_clh_SolarEquipmentMember_920BF11A1D0C3465381132A7180F4EE9" xlink:type="arc" />
    <link:label id="lab_us-gaap_RailroadTransportationEquipmentMember_40ED4E1CE5480BC97DD932A7180F682F_terseLabel_en-US" xlink:label="lab_us-gaap_RailroadTransportationEquipmentMember_40ED4E1CE5480BC97DD932A7180F682F" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Containers and railcars</link:label>
    <link:label id="lab_us-gaap_RailroadTransportationEquipmentMember_40ED4E1CE5480BC97DD932A7180F682F_label_en-US" xlink:label="lab_us-gaap_RailroadTransportationEquipmentMember_40ED4E1CE5480BC97DD932A7180F682F" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Railroad Transportation Equipment [Member]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RailroadTransportationEquipmentMember" xlink:label="loc_us-gaap_RailroadTransportationEquipmentMember_40ED4E1CE5480BC97DD932A7180F682F" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RailroadTransportationEquipmentMember_40ED4E1CE5480BC97DD932A7180F682F" xlink:to="lab_us-gaap_RailroadTransportationEquipmentMember_40ED4E1CE5480BC97DD932A7180F682F" xlink:type="arc" />
    <link:label id="lab_clh_AllOtherEquipmentMember_2EC1F42E5C5A90EC34B932A7180FB7A9_terseLabel_en-US" xlink:label="lab_clh_AllOtherEquipmentMember_2EC1F42E5C5A90EC34B932A7180FB7A9" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">All other equipment</link:label>
    <link:label id="lab_clh_AllOtherEquipmentMember_2EC1F42E5C5A90EC34B932A7180FB7A9_label_en-US" xlink:label="lab_clh_AllOtherEquipmentMember_2EC1F42E5C5A90EC34B932A7180FB7A9" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">All Other Equipment [member]</link:label>
    <link:label id="lab_clh_AllOtherEquipmentMember_2EC1F42E5C5A90EC34B932A7180FB7A9_documentation_en-US" xlink:label="lab_clh_AllOtherEquipmentMember_2EC1F42E5C5A90EC34B932A7180FB7A9" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the long-lived, depreciable assets used to produce goods and services.</link:label>
    <link:loc xlink:href="clh-20171231.xsd#clh_AllOtherEquipmentMember" xlink:label="loc_clh_AllOtherEquipmentMember_2EC1F42E5C5A90EC34B932A7180FB7A9" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_clh_AllOtherEquipmentMember_2EC1F42E5C5A90EC34B932A7180FB7A9" xlink:to="lab_clh_AllOtherEquipmentMember_2EC1F42E5C5A90EC34B932A7180FB7A9" xlink:type="arc" />
    <link:label id="lab_us-gaap_FurnitureAndFixturesMember_C3223F7133031D1C086732A7180FA2FD_terseLabel_en-US" xlink:label="lab_us-gaap_FurnitureAndFixturesMember_C3223F7133031D1C086732A7180FA2FD" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Furniture and fixtures</link:label>
    <link:label id="lab_us-gaap_FurnitureAndFixturesMember_C3223F7133031D1C086732A7180FA2FD_label_en-US" xlink:label="lab_us-gaap_FurnitureAndFixturesMember_C3223F7133031D1C086732A7180FA2FD" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Furniture and Fixtures [Member]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FurnitureAndFixturesMember" xlink:label="loc_us-gaap_FurnitureAndFixturesMember_C3223F7133031D1C086732A7180FA2FD" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FurnitureAndFixturesMember_C3223F7133031D1C086732A7180FA2FD" xlink:to="lab_us-gaap_FurnitureAndFixturesMember_C3223F7133031D1C086732A7180FA2FD" xlink:type="arc" />
    <link:label id="lab_us-gaap_PropertyPlantAndEquipmentLineItems_0E32B19DC3FDBD5AB3EB32A7180F4C05_terseLabel_en-US" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentLineItems_0E32B19DC3FDBD5AB3EB32A7180F4C05" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Property, Plant and Equipment [Line Items]</link:label>
    <link:label id="lab_us-gaap_PropertyPlantAndEquipmentLineItems_0E32B19DC3FDBD5AB3EB32A7180F4C05_label_en-US" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentLineItems_0E32B19DC3FDBD5AB3EB32A7180F4C05" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Property, Plant and Equipment [Line Items]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PropertyPlantAndEquipmentLineItems" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentLineItems_0E32B19DC3FDBD5AB3EB32A7180F4C05" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_0E32B19DC3FDBD5AB3EB32A7180F4C05" xlink:to="lab_us-gaap_PropertyPlantAndEquipmentLineItems_0E32B19DC3FDBD5AB3EB32A7180F4C05" xlink:type="arc" />
    <link:label id="lab_us-gaap_PropertyPlantAndEquipmentUsefulLife_167A40C2BB72B22A930632A7180F83E3_terseLabel_en-US" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentUsefulLife_167A40C2BB72B22A930632A7180F83E3" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Estimated useful life (in years)</link:label>
    <link:label id="lab_us-gaap_PropertyPlantAndEquipmentUsefulLife_167A40C2BB72B22A930632A7180F83E3_label_en-US" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentUsefulLife_167A40C2BB72B22A930632A7180F83E3" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Property, Plant and Equipment, Useful Life</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PropertyPlantAndEquipmentUsefulLife" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentUsefulLife_167A40C2BB72B22A930632A7180F83E3" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentUsefulLife_167A40C2BB72B22A930632A7180F83E3" xlink:to="lab_us-gaap_PropertyPlantAndEquipmentUsefulLife_167A40C2BB72B22A930632A7180F83E3" xlink:type="arc" />
    <link:label id="lab_clh_SignificantAccountingPoliciesAndRecentAccountingPronouncementsTextBlock_EF1464700F2442E1578F32A71779F647_terseLabel_en-US" xlink:label="lab_clh_SignificantAccountingPoliciesAndRecentAccountingPronouncementsTextBlock_EF1464700F2442E1578F32A71779F647" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">SIGNIFICANT ACCOUNTING POLICIES</link:label>
    <link:label id="lab_clh_SignificantAccountingPoliciesAndRecentAccountingPronouncementsTextBlock_EF1464700F2442E1578F32A71779F647_label_en-US" xlink:label="lab_clh_SignificantAccountingPoliciesAndRecentAccountingPronouncementsTextBlock_EF1464700F2442E1578F32A71779F647" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Significant Accounting Policies and Recent Accounting Pronouncements [Text Block]</link:label>
    <link:label id="lab_clh_SignificantAccountingPoliciesAndRecentAccountingPronouncementsTextBlock_EF1464700F2442E1578F32A71779F647_documentation_en-US" xlink:label="lab_clh_SignificantAccountingPoliciesAndRecentAccountingPronouncementsTextBlock_EF1464700F2442E1578F32A71779F647" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">This element may be used to describe all significant accounting policies of the reporting entity, an entity's explanation that the preparation of financial statements in conformity with generally accepted accounting principles requires the use of management estimates and the impact of recently issued accounting standards.</link:label>
    <link:loc xlink:href="clh-20171231.xsd#clh_SignificantAccountingPoliciesAndRecentAccountingPronouncementsTextBlock" xlink:label="loc_clh_SignificantAccountingPoliciesAndRecentAccountingPronouncementsTextBlock_EF1464700F2442E1578F32A71779F647" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_clh_SignificantAccountingPoliciesAndRecentAccountingPronouncementsTextBlock_EF1464700F2442E1578F32A71779F647" xlink:to="lab_clh_SignificantAccountingPoliciesAndRecentAccountingPronouncementsTextBlock_EF1464700F2442E1578F32A71779F647" xlink:type="arc" />
    <link:label id="lab_us-gaap_DefinedContributionPlanTable_D85C301C4DFA1D79B91829D457D99342_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedContributionPlanTable_D85C301C4DFA1D79B91829D457D99342" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Defined Contribution Plan [Table]</link:label>
    <link:label id="lab_us-gaap_DefinedContributionPlanTable_D85C301C4DFA1D79B91829D457D99342_label_en-US" xlink:label="lab_us-gaap_DefinedContributionPlanTable_D85C301C4DFA1D79B91829D457D99342" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Defined Contribution Plan [Table]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DefinedContributionPlanTable" xlink:label="loc_us-gaap_DefinedContributionPlanTable_D85C301C4DFA1D79B91829D457D99342" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedContributionPlanTable_D85C301C4DFA1D79B91829D457D99342" xlink:to="lab_us-gaap_DefinedContributionPlanTable_D85C301C4DFA1D79B91829D457D99342" xlink:type="arc" />
    <link:label id="lab_us-gaap_DefinedContributionPlanDisclosureLineItems_BCE8B1AA4EF9DC6187E829D457D9B838_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedContributionPlanDisclosureLineItems_BCE8B1AA4EF9DC6187E829D457D9B838" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Defined Contribution Plan Disclosure [Line Items]</link:label>
    <link:label id="lab_us-gaap_DefinedContributionPlanDisclosureLineItems_BCE8B1AA4EF9DC6187E829D457D9B838_label_en-US" xlink:label="lab_us-gaap_DefinedContributionPlanDisclosureLineItems_BCE8B1AA4EF9DC6187E829D457D9B838" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Defined Contribution Plan Disclosure [Line Items]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DefinedContributionPlanDisclosureLineItems" xlink:label="loc_us-gaap_DefinedContributionPlanDisclosureLineItems_BCE8B1AA4EF9DC6187E829D457D9B838" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedContributionPlanDisclosureLineItems_BCE8B1AA4EF9DC6187E829D457D9B838" xlink:to="lab_us-gaap_DefinedContributionPlanDisclosureLineItems_BCE8B1AA4EF9DC6187E829D457D9B838" xlink:type="arc" />
    <link:label id="lab_clh_NumberOfActiveNonSupervisoryCanadianEmployees_2424E37F335B91C8C45229D457D97758_terseLabel_en-US" xlink:label="lab_clh_NumberOfActiveNonSupervisoryCanadianEmployees_2424E37F335B91C8C45229D457D97758" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Number of active non-supervisory Canadian employees</link:label>
    <link:label id="lab_clh_NumberOfActiveNonSupervisoryCanadianEmployees_2424E37F335B91C8C45229D457D97758_label_en-US" xlink:label="lab_clh_NumberOfActiveNonSupervisoryCanadianEmployees_2424E37F335B91C8C45229D457D97758" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Number of active non-supervisory Canadian employees</link:label>
    <link:label id="lab_clh_NumberOfActiveNonSupervisoryCanadianEmployees_2424E37F335B91C8C45229D457D97758_documentation_en-US" xlink:label="lab_clh_NumberOfActiveNonSupervisoryCanadianEmployees_2424E37F335B91C8C45229D457D97758" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Number of active non-supervisory Canadian employees</link:label>
    <link:loc xlink:href="clh-20171231.xsd#clh_NumberOfActiveNonSupervisoryCanadianEmployees" xlink:label="loc_clh_NumberOfActiveNonSupervisoryCanadianEmployees_2424E37F335B91C8C45229D457D97758" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_clh_NumberOfActiveNonSupervisoryCanadianEmployees_2424E37F335B91C8C45229D457D97758" xlink:to="lab_clh_NumberOfActiveNonSupervisoryCanadianEmployees_2424E37F335B91C8C45229D457D97758" xlink:type="arc" />
    <link:label id="lab_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost_3560222EFFADA752BD0D29D457D93497_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost_3560222EFFADA752BD0D29D457D93497" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Net periodic benefit cost</link:label>
    <link:label id="lab_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost_3560222EFFADA752BD0D29D457D93497_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost_3560222EFFADA752BD0D29D457D93497" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Defined Benefit Plan, Net Periodic Benefit Cost (Credit)</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost" xlink:label="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost_3560222EFFADA752BD0D29D457D93497" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost_3560222EFFADA752BD0D29D457D93497" xlink:to="lab_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost_3560222EFFADA752BD0D29D457D93497" xlink:type="arc" />
    <link:label id="lab_us-gaap_DefinedBenefitPlanFairValueOfPlanAssets_7C388AC162A7EC1A403129D457D92F2D_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanFairValueOfPlanAssets_7C388AC162A7EC1A403129D457D92F2D" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Pension assets measured at fair value</link:label>
    <link:label id="lab_us-gaap_DefinedBenefitPlanFairValueOfPlanAssets_7C388AC162A7EC1A403129D457D92F2D_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanFairValueOfPlanAssets_7C388AC162A7EC1A403129D457D92F2D" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Defined Benefit Plan, Fair Value of Plan Assets</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DefinedBenefitPlanFairValueOfPlanAssets" xlink:label="loc_us-gaap_DefinedBenefitPlanFairValueOfPlanAssets_7C388AC162A7EC1A403129D457D92F2D" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanFairValueOfPlanAssets_7C388AC162A7EC1A403129D457D92F2D" xlink:to="lab_us-gaap_DefinedBenefitPlanFairValueOfPlanAssets_7C388AC162A7EC1A403129D457D92F2D" xlink:type="arc" />
    <link:label id="lab_us-gaap_DefinedBenefitPlanBenefitObligation_3889E2DB9AE98E88257B29D457D9ABED_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanBenefitObligation_3889E2DB9AE98E88257B29D457D9ABED" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Projected benefit obligation</link:label>
    <link:label id="lab_us-gaap_DefinedBenefitPlanBenefitObligation_3889E2DB9AE98E88257B29D457D9ABED_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanBenefitObligation_3889E2DB9AE98E88257B29D457D9ABED" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Defined Benefit Plan, Benefit Obligation</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DefinedBenefitPlanBenefitObligation" xlink:label="loc_us-gaap_DefinedBenefitPlanBenefitObligation_3889E2DB9AE98E88257B29D457D9ABED" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanBenefitObligation_3889E2DB9AE98E88257B29D457D9ABED" xlink:to="lab_us-gaap_DefinedBenefitPlanBenefitObligation_3889E2DB9AE98E88257B29D457D9ABED" xlink:type="arc" />
    <link:label id="lab_us-gaap_ScheduleOfGoodwillTable_583A7C1584F46F5494CAB3C48722FAD3_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfGoodwillTable_583A7C1584F46F5494CAB3C48722FAD3" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Schedule of Goodwill [Table]</link:label>
    <link:label id="lab_us-gaap_ScheduleOfGoodwillTable_583A7C1584F46F5494CAB3C48722FAD3_label_en-US" xlink:label="lab_us-gaap_ScheduleOfGoodwillTable_583A7C1584F46F5494CAB3C48722FAD3" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Schedule of Goodwill [Table]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfGoodwillTable" xlink:label="loc_us-gaap_ScheduleOfGoodwillTable_583A7C1584F46F5494CAB3C48722FAD3" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfGoodwillTable_583A7C1584F46F5494CAB3C48722FAD3" xlink:to="lab_us-gaap_ScheduleOfGoodwillTable_583A7C1584F46F5494CAB3C48722FAD3" xlink:type="arc" />
    <link:label id="lab_us-gaap_GoodwillLineItems_8371FA0A3F3B53E02E14B3C487236796_terseLabel_en-US" xlink:label="lab_us-gaap_GoodwillLineItems_8371FA0A3F3B53E02E14B3C487236796" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Goodwill [Line Items]</link:label>
    <link:label id="lab_us-gaap_GoodwillLineItems_8371FA0A3F3B53E02E14B3C487236796_label_en-US" xlink:label="lab_us-gaap_GoodwillLineItems_8371FA0A3F3B53E02E14B3C487236796" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Goodwill [Line Items]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_GoodwillLineItems" xlink:label="loc_us-gaap_GoodwillLineItems_8371FA0A3F3B53E02E14B3C487236796" xlink:type="locator" />
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    <link:label id="lab_clh_NonCommercialLandfillsMember_6A33225F685F07F85591BCEC04A2DF43_terseLabel_en-US" xlink:label="lab_clh_NonCommercialLandfillsMember_6A33225F685F07F85591BCEC04A2DF43" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Non-commercial landfills</link:label>
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    <link:label id="lab_clh_PermittedMember_18D7C770FB51D32079AFBCEC04A2C9CA_documentation_en-US" xlink:label="lab_clh_PermittedMember_18D7C770FB51D32079AFBCEC04A2C9CA" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Permitted [Member]</link:label>
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    <link:label id="lab_us-gaap_PropertyPlantAndEquipmentLineItems_32F2B88CDA058FCA6EF6BCEC04A21E9E_verboseLabel_en-US" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentLineItems_32F2B88CDA058FCA6EF6BCEC04A21E9E" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Property, Plant and Equipment [Line Items]</link:label>
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    <link:loc xlink:href="clh-20171231.xsd#clh_NumberOfExpansions" xlink:label="loc_clh_NumberOfExpansions_B4766F32F9C7D785A217BCEC04A23E92" xlink:type="locator" />
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    <link:loc xlink:href="clh-20171231.xsd#clh_NumberOfServiceLocationsWithUnpermittedExpansion" xlink:label="loc_clh_NumberOfServiceLocationsWithUnpermittedExpansion_9D690E3D5A88124B4F32BCEC04A24761" xlink:type="locator" />
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    <link:label id="lab_clh_PercentageOfAirspaceRemaining_1513EE4C48F1C044185CBCEC04A23AEF_terseLabel_en-US" xlink:label="lab_clh_PercentageOfAirspaceRemaining_1513EE4C48F1C044185CBCEC04A23AEF" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Percentage of airspace remaining</link:label>
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    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_clh_ConcentrationRiskNumberofMajorCustomersOverBenchmark_87111191BB784DD4B5E932A718A62DDB" xlink:to="lab_clh_ConcentrationRiskNumberofMajorCustomersOverBenchmark_87111191BB784DD4B5E932A718A62DDB" xlink:type="arc" />
    <link:label id="lab_us-gaap_AccrualForEnvironmentalLossContingenciesIncreaseDecreaseForRevisionInEstimates_93A44311E873CB8A3E6E33995BC52726_terseLabel_en-US" xlink:label="lab_us-gaap_AccrualForEnvironmentalLossContingenciesIncreaseDecreaseForRevisionInEstimates_93A44311E873CB8A3E6E33995BC52726" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Changes in estimates recorded to statement of income (loss)</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AccrualForEnvironmentalLossContingenciesIncreaseDecreaseForRevisionInEstimates" xlink:label="loc_us-gaap_AccrualForEnvironmentalLossContingenciesIncreaseDecreaseForRevisionInEstimates_93A44311E873CB8A3E6E33995BC52726" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AccrualForEnvironmentalLossContingenciesIncreaseDecreaseForRevisionInEstimates_93A44311E873CB8A3E6E33995BC52726" xlink:to="lab_us-gaap_AccrualForEnvironmentalLossContingenciesIncreaseDecreaseForRevisionInEstimates_93A44311E873CB8A3E6E33995BC52726" xlink:type="arc" />
    <link:label id="lab_us-gaap_AccrualForEnvironmentalLossContingencies_D645A4EF880DCF78F2BC33995BC6CA7F_terseLabel_en-US" xlink:label="lab_us-gaap_AccrualForEnvironmentalLossContingencies_D645A4EF880DCF78F2BC33995BC6CA7F" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Future remediation liability</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AccrualForEnvironmentalLossContingencies" xlink:label="loc_us-gaap_AccrualForEnvironmentalLossContingencies_D645A4EF880DCF78F2BC33995BC6CA7F" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AccrualForEnvironmentalLossContingencies_D645A4EF880DCF78F2BC33995BC6CA7F" xlink:to="lab_us-gaap_AccrualForEnvironmentalLossContingencies_D645A4EF880DCF78F2BC33995BC6CA7F" xlink:type="arc" />
    <link:label id="lab_clh_PossibleIncreaseInTotalRemedialLiabilities_634D4EF29DF40050950133995BC6236E_terseLabel_en-US" xlink:label="lab_clh_PossibleIncreaseInTotalRemedialLiabilities_634D4EF29DF40050950133995BC6236E" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Possible increase in total remedial liabilities</link:label>
    <link:label id="lab_clh_PossibleIncreaseInTotalRemedialLiabilities_634D4EF29DF40050950133995BC6236E_label_en-US" xlink:label="lab_clh_PossibleIncreaseInTotalRemedialLiabilities_634D4EF29DF40050950133995BC6236E" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Possible Increase in Total Remedial Liabilities</link:label>
    <link:label id="lab_clh_PossibleIncreaseInTotalRemedialLiabilities_634D4EF29DF40050950133995BC6236E_documentation_en-US" xlink:label="lab_clh_PossibleIncreaseInTotalRemedialLiabilities_634D4EF29DF40050950133995BC6236E" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Possible Increase in Total Remedial Liabilities</link:label>
    <link:loc xlink:href="clh-20171231.xsd#clh_PossibleIncreaseInTotalRemedialLiabilities" xlink:label="loc_clh_PossibleIncreaseInTotalRemedialLiabilities_634D4EF29DF40050950133995BC6236E" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_clh_PossibleIncreaseInTotalRemedialLiabilities_634D4EF29DF40050950133995BC6236E" xlink:to="lab_clh_PossibleIncreaseInTotalRemedialLiabilities_634D4EF29DF40050950133995BC6236E" xlink:type="arc" />
    <link:label id="lab_clh_AccrualforEnvironmentalLossContingenciesThresholdForDisclosure_96C9B97410B6A72DA67033995BC69BD6_terseLabel_en-US" xlink:label="lab_clh_AccrualforEnvironmentalLossContingenciesThresholdForDisclosure_96C9B97410B6A72DA67033995BC69BD6" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Accrual for environmental loss contingencies, threshold for disclosure (as a percent)</link:label>
    <link:label id="lab_clh_AccrualforEnvironmentalLossContingenciesThresholdForDisclosure_96C9B97410B6A72DA67033995BC69BD6_label_en-US" xlink:label="lab_clh_AccrualforEnvironmentalLossContingenciesThresholdForDisclosure_96C9B97410B6A72DA67033995BC69BD6" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Accrual for Environmental Loss Contingencies, Threshold For Disclosure</link:label>
    <link:label id="lab_clh_AccrualforEnvironmentalLossContingenciesThresholdForDisclosure_96C9B97410B6A72DA67033995BC69BD6_documentation_en-US" xlink:label="lab_clh_AccrualforEnvironmentalLossContingenciesThresholdForDisclosure_96C9B97410B6A72DA67033995BC69BD6" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Accrual for Environmental Loss Contingencies, Threshold For Disclosure</link:label>
    <link:loc xlink:href="clh-20171231.xsd#clh_AccrualforEnvironmentalLossContingenciesThresholdForDisclosure" xlink:label="loc_clh_AccrualforEnvironmentalLossContingenciesThresholdForDisclosure_96C9B97410B6A72DA67033995BC69BD6" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_clh_AccrualforEnvironmentalLossContingenciesThresholdForDisclosure_96C9B97410B6A72DA67033995BC69BD6" xlink:to="lab_clh_AccrualforEnvironmentalLossContingenciesThresholdForDisclosure_96C9B97410B6A72DA67033995BC69BD6" xlink:type="arc" />
    <link:label id="lab_us-gaap_AssetsCurrentAbstract_C1BEA0375F9B4AD0FE9AD8E481D45AA7_terseLabel_en-US" xlink:label="lab_us-gaap_AssetsCurrentAbstract_C1BEA0375F9B4AD0FE9AD8E481D45AA7" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Current assets:</link:label>
    <link:label id="lab_us-gaap_AssetsCurrentAbstract_C1BEA0375F9B4AD0FE9AD8E481D45AA7_label_en-US" xlink:label="lab_us-gaap_AssetsCurrentAbstract_C1BEA0375F9B4AD0FE9AD8E481D45AA7" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Assets, Current [Abstract]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AssetsCurrentAbstract" xlink:label="loc_us-gaap_AssetsCurrentAbstract_C1BEA0375F9B4AD0FE9AD8E481D45AA7" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AssetsCurrentAbstract_C1BEA0375F9B4AD0FE9AD8E481D45AA7" xlink:to="lab_us-gaap_AssetsCurrentAbstract_C1BEA0375F9B4AD0FE9AD8E481D45AA7" xlink:type="arc" />
    <link:label id="lab_us-gaap_CashAndCashEquivalentsAtCarryingValue_82B5C2D8088C2DE7DB82D8E481D471D6_terseLabel_en-US" xlink:label="lab_us-gaap_CashAndCashEquivalentsAtCarryingValue_82B5C2D8088C2DE7DB82D8E481D471D6" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Cash and cash equivalents</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:label="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_82B5C2D8088C2DE7DB82D8E481D471D6" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_82B5C2D8088C2DE7DB82D8E481D471D6" xlink:to="lab_us-gaap_CashAndCashEquivalentsAtCarryingValue_82B5C2D8088C2DE7DB82D8E481D471D6" xlink:type="arc" />
    <link:label id="lab_us-gaap_AccountsReceivableNetCurrent_3574F692579CE21B35D4D8E481D4CBB1_terseLabel_en-US" xlink:label="lab_us-gaap_AccountsReceivableNetCurrent_3574F692579CE21B35D4D8E481D4CBB1" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Accounts receivable, net of allowances aggregating $27,799 and $29,249, respectively</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AccountsReceivableNetCurrent" xlink:label="loc_us-gaap_AccountsReceivableNetCurrent_3574F692579CE21B35D4D8E481D4CBB1" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AccountsReceivableNetCurrent_3574F692579CE21B35D4D8E481D4CBB1" xlink:to="lab_us-gaap_AccountsReceivableNetCurrent_3574F692579CE21B35D4D8E481D4CBB1" xlink:type="arc" />
    <link:label id="lab_clh_UnbilledAccountsReceivableCurrent_BB455CF189B98BB1B9D5D8E481D4B80C_terseLabel_en-US" xlink:label="lab_clh_UnbilledAccountsReceivableCurrent_BB455CF189B98BB1B9D5D8E481D4B80C" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Unbilled accounts receivable</link:label>
    <link:label id="lab_clh_UnbilledAccountsReceivableCurrent_BB455CF189B98BB1B9D5D8E481D4B80C_label_en-US" xlink:label="lab_clh_UnbilledAccountsReceivableCurrent_BB455CF189B98BB1B9D5D8E481D4B80C" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Unbilled Accounts Receivable, Current</link:label>
    <link:label id="lab_clh_UnbilledAccountsReceivableCurrent_BB455CF189B98BB1B9D5D8E481D4B80C_documentation_en-US" xlink:label="lab_clh_UnbilledAccountsReceivableCurrent_BB455CF189B98BB1B9D5D8E481D4B80C" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">The aggregate amount of unbilled receivables due for services rendered or to be rendered at the financial statement date, which are usually due within one year (or one business cycle).</link:label>
    <link:loc xlink:href="clh-20171231.xsd#clh_UnbilledAccountsReceivableCurrent" xlink:label="loc_clh_UnbilledAccountsReceivableCurrent_BB455CF189B98BB1B9D5D8E481D4B80C" xlink:type="locator" />
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    <link:label id="lab_us-gaap_DeferredFinanceCostsCurrentNet_63669620D129D4D9D0D4D8E481D4D6C4_terseLabel_en-US" xlink:label="lab_us-gaap_DeferredFinanceCostsCurrentNet_63669620D129D4D9D0D4D8E481D4D6C4" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Deferred costs</link:label>
    <link:label id="lab_us-gaap_DeferredFinanceCostsCurrentNet_63669620D129D4D9D0D4D8E481D4D6C4_label_en-US" xlink:label="lab_us-gaap_DeferredFinanceCostsCurrentNet_63669620D129D4D9D0D4D8E481D4D6C4" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Debt Issuance Costs, Current, Net</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DeferredFinanceCostsCurrentNet" xlink:label="loc_us-gaap_DeferredFinanceCostsCurrentNet_63669620D129D4D9D0D4D8E481D4D6C4" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DeferredFinanceCostsCurrentNet_63669620D129D4D9D0D4D8E481D4D6C4" xlink:to="lab_us-gaap_DeferredFinanceCostsCurrentNet_63669620D129D4D9D0D4D8E481D4D6C4" xlink:type="arc" />
    <link:label id="lab_us-gaap_Supplies_FE05BF2B7C32CA599718D8E481D47BCE_terseLabel_en-US" xlink:label="lab_us-gaap_Supplies_FE05BF2B7C32CA599718D8E481D47BCE" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Inventories and supplies</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_Supplies" xlink:label="loc_us-gaap_Supplies_FE05BF2B7C32CA599718D8E481D47BCE" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_Supplies_FE05BF2B7C32CA599718D8E481D47BCE" xlink:to="lab_us-gaap_Supplies_FE05BF2B7C32CA599718D8E481D47BCE" xlink:type="arc" />
    <link:label id="lab_clh_PrepaidExpensesAndOtherAssetsCurrent_F56A48DD74C7CAF08037D8E481D4D08E_terseLabel_en-US" xlink:label="lab_clh_PrepaidExpensesAndOtherAssetsCurrent_F56A48DD74C7CAF08037D8E481D4D08E" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Prepaid expenses and other current assets</link:label>
    <link:label id="lab_clh_PrepaidExpensesAndOtherAssetsCurrent_F56A48DD74C7CAF08037D8E481D4D08E_label_en-US" xlink:label="lab_clh_PrepaidExpensesAndOtherAssetsCurrent_F56A48DD74C7CAF08037D8E481D4D08E" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Prepaid Expenses and Other Assets, Current</link:label>
    <link:label id="lab_clh_PrepaidExpensesAndOtherAssetsCurrent_F56A48DD74C7CAF08037D8E481D4D08E_documentation_en-US" xlink:label="lab_clh_PrepaidExpensesAndOtherAssetsCurrent_F56A48DD74C7CAF08037D8E481D4D08E" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">This element represents current portion of prepaid expenses and other assets.</link:label>
    <link:loc xlink:href="clh-20171231.xsd#clh_PrepaidExpensesAndOtherAssetsCurrent" xlink:label="loc_clh_PrepaidExpensesAndOtherAssetsCurrent_F56A48DD74C7CAF08037D8E481D4D08E" xlink:type="locator" />
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    <link:label id="lab_us-gaap_AssetsCurrent_439E99CFCB0FC7234FD2D8E481D4167B_totalLabel_en-US" xlink:label="lab_us-gaap_AssetsCurrent_439E99CFCB0FC7234FD2D8E481D4167B" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Total current assets</link:label>
    <link:label id="lab_us-gaap_AssetsCurrent_439E99CFCB0FC7234FD2D8E481D4167B_label_en-US" xlink:label="lab_us-gaap_AssetsCurrent_439E99CFCB0FC7234FD2D8E481D4167B" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Assets, Current</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AssetsCurrent" xlink:label="loc_us-gaap_AssetsCurrent_439E99CFCB0FC7234FD2D8E481D4167B" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AssetsCurrent_439E99CFCB0FC7234FD2D8E481D4167B" xlink:to="lab_us-gaap_AssetsCurrent_439E99CFCB0FC7234FD2D8E481D4167B" xlink:type="arc" />
    <link:label id="lab_us-gaap_OtherAssetsAbstract_6FCA8FA5100860FD873FD8E481D4533C_terseLabel_en-US" xlink:label="lab_us-gaap_OtherAssetsAbstract_6FCA8FA5100860FD873FD8E481D4533C" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Other assets:</link:label>
    <link:label id="lab_us-gaap_OtherAssetsAbstract_6FCA8FA5100860FD873FD8E481D4533C_label_en-US" xlink:label="lab_us-gaap_OtherAssetsAbstract_6FCA8FA5100860FD873FD8E481D4533C" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Other Assets [Abstract]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherAssetsAbstract" xlink:label="loc_us-gaap_OtherAssetsAbstract_6FCA8FA5100860FD873FD8E481D4533C" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherAssetsAbstract_6FCA8FA5100860FD873FD8E481D4533C" xlink:to="lab_us-gaap_OtherAssetsAbstract_6FCA8FA5100860FD873FD8E481D4533C" xlink:type="arc" />
    <link:label id="lab_us-gaap_OtherAssetsNoncurrent_A02E0BF763A6B55880AED8E481D52D44_terseLabel_en-US" xlink:label="lab_us-gaap_OtherAssetsNoncurrent_A02E0BF763A6B55880AED8E481D52D44" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Other</link:label>
    <link:label id="lab_us-gaap_OtherAssetsNoncurrent_A02E0BF763A6B55880AED8E481D52D44_label_en-US" xlink:label="lab_us-gaap_OtherAssetsNoncurrent_A02E0BF763A6B55880AED8E481D52D44" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Other Assets, Noncurrent</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherAssetsNoncurrent" xlink:label="loc_us-gaap_OtherAssetsNoncurrent_A02E0BF763A6B55880AED8E481D52D44" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherAssetsNoncurrent_A02E0BF763A6B55880AED8E481D52D44" xlink:to="lab_us-gaap_OtherAssetsNoncurrent_A02E0BF763A6B55880AED8E481D52D44" xlink:type="arc" />
    <link:label id="lab_clh_AssetsNoncurrentExcludingPropertyPlantAndEquipment_0A26FD678939AF78CBE2D8E481D57CF7_totalLabel_en-US" xlink:label="lab_clh_AssetsNoncurrentExcludingPropertyPlantAndEquipment_0A26FD678939AF78CBE2D8E481D57CF7" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Total other assets</link:label>
    <link:label id="lab_clh_AssetsNoncurrentExcludingPropertyPlantAndEquipment_0A26FD678939AF78CBE2D8E481D57CF7_label_en-US" xlink:label="lab_clh_AssetsNoncurrentExcludingPropertyPlantAndEquipment_0A26FD678939AF78CBE2D8E481D57CF7" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Assets, Noncurrent, Excluding Property, Plant and Equipment</link:label>
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    <link:label id="lab_clh_OtherLiabilitesAbstract_05E9F676843363B35D36D8E481D5A13F_label_en-US" xlink:label="lab_clh_OtherLiabilitesAbstract_05E9F676843363B35D36D8E481D5A13F" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Other Liabilites [Abstract]</link:label>
    <link:label id="lab_clh_OtherLiabilitesAbstract_05E9F676843363B35D36D8E481D5A13F_documentation_en-US" xlink:label="lab_clh_OtherLiabilitesAbstract_05E9F676843363B35D36D8E481D5A13F" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Other Liabilites [Abstract]</link:label>
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    <link:label id="lab_clh_AnticipatedSelfInsurancePaymentsYearThree_7A9995ABC3D7B300FC63BE2CAC6EF21A_terseLabel_en-US" xlink:label="lab_clh_AnticipatedSelfInsurancePaymentsYearThree_7A9995ABC3D7B300FC63BE2CAC6EF21A" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2020</link:label>
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    <link:label id="lab_clh_AnticipatedSelfInsurancePaymentsYearFive_8EA3ED85395E82A68FB7BE2CAC6ECECE_terseLabel_en-US" xlink:label="lab_clh_AnticipatedSelfInsurancePaymentsYearFive_8EA3ED85395E82A68FB7BE2CAC6ECECE" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2022</link:label>
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    <link:label id="lab_clh_CertainOtherThirdPartySitesMember_38E53589D0F0CA243A2F32A718F44A4C_terseLabel_en-US" xlink:label="lab_clh_CertainOtherThirdPartySitesMember_38E53589D0F0CA243A2F32A718F44A4C" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Certain other third party sites</link:label>
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    <link:label id="lab_clh_CertainOtherThirdPartySitesMember_38E53589D0F0CA243A2F32A718F44A4C_documentation_en-US" xlink:label="lab_clh_CertainOtherThirdPartySitesMember_38E53589D0F0CA243A2F32A718F44A4C" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the details that pertain to Certain Other Third Party Sites.</link:label>
    <link:loc xlink:href="clh-20171231.xsd#clh_CertainOtherThirdPartySitesMember" xlink:label="loc_clh_CertainOtherThirdPartySitesMember_38E53589D0F0CA243A2F32A718F44A4C" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_clh_CertainOtherThirdPartySitesMember_38E53589D0F0CA243A2F32A718F44A4C" xlink:to="lab_clh_CertainOtherThirdPartySitesMember_38E53589D0F0CA243A2F32A718F44A4C" xlink:type="arc" />
    <link:label id="lab_clh_ContingenciesLineItems_C9135E522F7EBD53B47B32A718F579C9_terseLabel_en-US" xlink:label="lab_clh_ContingenciesLineItems_C9135E522F7EBD53B47B32A718F579C9" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Contingencies</link:label>
    <link:label id="lab_clh_ContingenciesLineItems_C9135E522F7EBD53B47B32A718F579C9_label_en-US" xlink:label="lab_clh_ContingenciesLineItems_C9135E522F7EBD53B47B32A718F579C9" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Contingencies [Line Items]</link:label>
    <link:label id="lab_clh_ContingenciesLineItems_C9135E522F7EBD53B47B32A718F579C9_documentation_en-US" xlink:label="lab_clh_ContingenciesLineItems_C9135E522F7EBD53B47B32A718F579C9" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">-- None. No documentation exists for this element. --</link:label>
    <link:loc xlink:href="clh-20171231.xsd#clh_ContingenciesLineItems" xlink:label="loc_clh_ContingenciesLineItems_C9135E522F7EBD53B47B32A718F579C9" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_clh_ContingenciesLineItems_C9135E522F7EBD53B47B32A718F579C9" xlink:to="lab_clh_ContingenciesLineItems_C9135E522F7EBD53B47B32A718F579C9" xlink:type="arc" />
    <link:label id="lab_clh_SuperfundProceedingsAbstract_4675419EF6D6369FACFC32A718F5623A_terseLabel_en-US" xlink:label="lab_clh_SuperfundProceedingsAbstract_4675419EF6D6369FACFC32A718F5623A" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Superfund Proceedings</link:label>
    <link:label id="lab_clh_SuperfundProceedingsAbstract_4675419EF6D6369FACFC32A718F5623A_label_en-US" xlink:label="lab_clh_SuperfundProceedingsAbstract_4675419EF6D6369FACFC32A718F5623A" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Superfund Proceedings [Abstract]</link:label>
    <link:label id="lab_clh_SuperfundProceedingsAbstract_4675419EF6D6369FACFC32A718F5623A_documentation_en-US" xlink:label="lab_clh_SuperfundProceedingsAbstract_4675419EF6D6369FACFC32A718F5623A" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">-- None. No documentation exists for this element. --</link:label>
    <link:loc xlink:href="clh-20171231.xsd#clh_SuperfundProceedingsAbstract" xlink:label="loc_clh_SuperfundProceedingsAbstract_4675419EF6D6369FACFC32A718F5623A" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_clh_SuperfundProceedingsAbstract_4675419EF6D6369FACFC32A718F5623A" xlink:to="lab_clh_SuperfundProceedingsAbstract_4675419EF6D6369FACFC32A718F5623A" xlink:type="arc" />
    <link:label id="lab_clh_SiteContingencyNumberOfSites_9746310484B454919C7832A718F56B00_totalLabel_en-US" xlink:label="lab_clh_SiteContingencyNumberOfSites_9746310484B454919C7832A718F56B00" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Number of sites subject to proceedings under federal or state superfund laws</link:label>
    <link:label id="lab_clh_SiteContingencyNumberOfSites_9746310484B454919C7832A718F56B00_label_en-US" xlink:label="lab_clh_SiteContingencyNumberOfSites_9746310484B454919C7832A718F56B00" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Site Contingency, Number of Sites</link:label>
    <link:label id="lab_clh_SiteContingencyNumberOfSites_9746310484B454919C7832A718F56B00_documentation_en-US" xlink:label="lab_clh_SiteContingencyNumberOfSites_9746310484B454919C7832A718F56B00" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">The number of sites that are subject to proceedings under federal or state superfund laws brought against the company or against third parties for which the company may have certain indemnification obligations.</link:label>
    <link:loc xlink:href="clh-20171231.xsd#clh_SiteContingencyNumberOfSites" xlink:label="loc_clh_SiteContingencyNumberOfSites_9746310484B454919C7832A718F56B00" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_clh_SiteContingencyNumberOfSites_9746310484B454919C7832A718F56B00" xlink:to="lab_clh_SiteContingencyNumberOfSites_9746310484B454919C7832A718F56B00" xlink:type="arc" />
    <link:label id="lab_clh_SiteContingencyNumberOfSitesOwnedByEntity_1204CF33ACF522AA252132A718F5CFC1_verboseLabel_en-US" xlink:label="lab_clh_SiteContingencyNumberOfSitesOwnedByEntity_1204CF33ACF522AA252132A718F5CFC1" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Number of sites owned by the entity subject to proceedings under federal or state superfund laws</link:label>
    <link:loc xlink:href="clh-20171231.xsd#clh_SiteContingencyNumberOfSitesOwnedByEntity" xlink:label="loc_clh_SiteContingencyNumberOfSitesOwnedByEntity_1204CF33ACF522AA252132A718F5CFC1" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_clh_SiteContingencyNumberOfSitesOwnedByEntity_1204CF33ACF522AA252132A718F5CFC1" xlink:to="lab_clh_SiteContingencyNumberOfSitesOwnedByEntity_1204CF33ACF522AA252132A718F5CFC1" xlink:type="arc" />
    <link:label id="lab_clh_SiteContingencyNumberOfSitesOwnedByThirdParty_C7CFC867F480D3633DC532A718F5534C_totalLabel_en-US" xlink:label="lab_clh_SiteContingencyNumberOfSitesOwnedByThirdParty_C7CFC867F480D3633DC532A718F5534C" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Number of sites owned by third parties subject to proceedings under federal or state superfund laws</link:label>
    <link:label id="lab_clh_SiteContingencyNumberOfSitesOwnedByThirdParty_C7CFC867F480D3633DC532A718F5534C_label_en-US" xlink:label="lab_clh_SiteContingencyNumberOfSitesOwnedByThirdParty_C7CFC867F480D3633DC532A718F5534C" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Site Contingency, Number of Sites Owned by Third Party</link:label>
    <link:label id="lab_clh_SiteContingencyNumberOfSitesOwnedByThirdParty_C7CFC867F480D3633DC532A718F5534C_documentation_en-US" xlink:label="lab_clh_SiteContingencyNumberOfSitesOwnedByThirdParty_C7CFC867F480D3633DC532A718F5534C" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">The number of sites owned by third parties subject to proceedings under federal or state Superfund laws for which the company or the prior owners shipped wastes.</link:label>
    <link:loc xlink:href="clh-20171231.xsd#clh_SiteContingencyNumberOfSitesOwnedByThirdParty" xlink:label="loc_clh_SiteContingencyNumberOfSitesOwnedByThirdParty_C7CFC867F480D3633DC532A718F5534C" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_clh_SiteContingencyNumberOfSitesOwnedByThirdParty_C7CFC867F480D3633DC532A718F5534C" xlink:to="lab_clh_SiteContingencyNumberOfSitesOwnedByThirdParty_C7CFC867F480D3633DC532A718F5534C" xlink:type="arc" />
    <link:label id="lab_clh_SiteContingencyEnvironmentalRemediationExpenseSettledNumberOfSitesOwnedByThirdParty_4BA3977DDE479D1FC98932A718F57095_terseLabel_en-US" xlink:label="lab_clh_SiteContingencyEnvironmentalRemediationExpenseSettledNumberOfSitesOwnedByThirdParty_4BA3977DDE479D1FC98932A718F57095" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Number of sites for which environmental remediation expense is settled</link:label>
    <link:label id="lab_clh_SiteContingencyEnvironmentalRemediationExpenseSettledNumberOfSitesOwnedByThirdParty_4BA3977DDE479D1FC98932A718F57095_label_en-US" xlink:label="lab_clh_SiteContingencyEnvironmentalRemediationExpenseSettledNumberOfSitesOwnedByThirdParty_4BA3977DDE479D1FC98932A718F57095" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Site Contingency, Environmental Remediation Expense Settled Number of Sites Owned by Third Party</link:label>
    <link:label id="lab_clh_SiteContingencyEnvironmentalRemediationExpenseSettledNumberOfSitesOwnedByThirdParty_4BA3977DDE479D1FC98932A718F57095_documentation_en-US" xlink:label="lab_clh_SiteContingencyEnvironmentalRemediationExpenseSettledNumberOfSitesOwnedByThirdParty_4BA3977DDE479D1FC98932A718F57095" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">The number of sites owned by the third party for which environmental remediation expense is settled.</link:label>
    <link:loc xlink:href="clh-20171231.xsd#clh_SiteContingencyEnvironmentalRemediationExpenseSettledNumberOfSitesOwnedByThirdParty" xlink:label="loc_clh_SiteContingencyEnvironmentalRemediationExpenseSettledNumberOfSitesOwnedByThirdParty_4BA3977DDE479D1FC98932A718F57095" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_clh_SiteContingencyEnvironmentalRemediationExpenseSettledNumberOfSitesOwnedByThirdParty_4BA3977DDE479D1FC98932A718F57095" xlink:to="lab_clh_SiteContingencyEnvironmentalRemediationExpenseSettledNumberOfSitesOwnedByThirdParty_4BA3977DDE479D1FC98932A718F57095" xlink:type="arc" />
    <link:label id="lab_clh_SiteContingencyEnvironmentalRemediationExpenseNumberOfSitesOwnedByThirdParty_E30CE4E6F992830F9D3732A718F57D89_terseLabel_en-US" xlink:label="lab_clh_SiteContingencyEnvironmentalRemediationExpenseNumberOfSitesOwnedByThirdParty_E30CE4E6F992830F9D3732A718F57D89" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Third party sites requiring expenditure on remediation</link:label>
    <link:label id="lab_clh_SiteContingencyEnvironmentalRemediationExpenseNumberOfSitesOwnedByThirdParty_E30CE4E6F992830F9D3732A718F57D89_label_en-US" xlink:label="lab_clh_SiteContingencyEnvironmentalRemediationExpenseNumberOfSitesOwnedByThirdParty_E30CE4E6F992830F9D3732A718F57D89" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Site Contingency, Environmental Remediation Expense Number of Sites Owned by Third Party</link:label>
    <link:label id="lab_clh_SiteContingencyEnvironmentalRemediationExpenseNumberOfSitesOwnedByThirdParty_E30CE4E6F992830F9D3732A718F57D89_documentation_en-US" xlink:label="lab_clh_SiteContingencyEnvironmentalRemediationExpenseNumberOfSitesOwnedByThirdParty_E30CE4E6F992830F9D3732A718F57D89" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">The number of sites for which environmental remediation expense is incurred subject to proceedings under federal or state superfund laws owned by third party.</link:label>
    <link:loc xlink:href="clh-20171231.xsd#clh_SiteContingencyEnvironmentalRemediationExpenseNumberOfSitesOwnedByThirdParty" xlink:label="loc_clh_SiteContingencyEnvironmentalRemediationExpenseNumberOfSitesOwnedByThirdParty_E30CE4E6F992830F9D3732A718F57D89" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_clh_SiteContingencyEnvironmentalRemediationExpenseNumberOfSitesOwnedByThirdParty_E30CE4E6F992830F9D3732A718F57D89" xlink:to="lab_clh_SiteContingencyEnvironmentalRemediationExpenseNumberOfSitesOwnedByThirdParty_E30CE4E6F992830F9D3732A718F57D89" xlink:type="arc" />
    <link:label id="lab_clh_SiteContingencyNotRequiringEnvironmentalRemediationExpenseNumberOfSitesOwnedByThirdParty_091945EA6DA3FEA4686332A718F5C862_terseLabel_en-US" xlink:label="lab_clh_SiteContingencyNotRequiringEnvironmentalRemediationExpenseNumberOfSitesOwnedByThirdParty_091945EA6DA3FEA4686332A718F5C862" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Number of sites for which environmental remediation expense is not required</link:label>
    <link:label id="lab_clh_SiteContingencyNotRequiringEnvironmentalRemediationExpenseNumberOfSitesOwnedByThirdParty_091945EA6DA3FEA4686332A718F5C862_label_en-US" xlink:label="lab_clh_SiteContingencyNotRequiringEnvironmentalRemediationExpenseNumberOfSitesOwnedByThirdParty_091945EA6DA3FEA4686332A718F5C862" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Site Contingency, Not Requiring Environmental Remediation Expense Number of Sites Owned by Third Party</link:label>
    <link:label id="lab_clh_SiteContingencyNotRequiringEnvironmentalRemediationExpenseNumberOfSitesOwnedByThirdParty_091945EA6DA3FEA4686332A718F5C862_documentation_en-US" xlink:label="lab_clh_SiteContingencyNotRequiringEnvironmentalRemediationExpenseNumberOfSitesOwnedByThirdParty_091945EA6DA3FEA4686332A718F5C862" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">The number of sites owned by the third party for which environmental remediation expense is not required.</link:label>
    <link:loc xlink:href="clh-20171231.xsd#clh_SiteContingencyNotRequiringEnvironmentalRemediationExpenseNumberOfSitesOwnedByThirdParty" xlink:label="loc_clh_SiteContingencyNotRequiringEnvironmentalRemediationExpenseNumberOfSitesOwnedByThirdParty_091945EA6DA3FEA4686332A718F5C862" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_clh_SiteContingencyNotRequiringEnvironmentalRemediationExpenseNumberOfSitesOwnedByThirdParty_091945EA6DA3FEA4686332A718F5C862" xlink:to="lab_clh_SiteContingencyNotRequiringEnvironmentalRemediationExpenseNumberOfSitesOwnedByThirdParty_091945EA6DA3FEA4686332A718F5C862" xlink:type="arc" />
    <link:label id="lab_clh_NumberofSitesPotentialLiabilityExceedsSubstantialQuota_1145586B72EDCA7BCB8B32A718F59DEA_terseLabel_en-US" xlink:label="lab_clh_NumberofSitesPotentialLiabilityExceedsSubstantialQuota_1145586B72EDCA7BCB8B32A718F59DEA" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Number of sites which potential liability could exceed $100,000</link:label>
    <link:label id="lab_clh_NumberofSitesPotentialLiabilityExceedsSubstantialQuota_1145586B72EDCA7BCB8B32A718F59DEA_label_en-US" xlink:label="lab_clh_NumberofSitesPotentialLiabilityExceedsSubstantialQuota_1145586B72EDCA7BCB8B32A718F59DEA" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Number of Sites, Potential Liability Exceeds Substantial Quota</link:label>
    <link:label id="lab_clh_NumberofSitesPotentialLiabilityExceedsSubstantialQuota_1145586B72EDCA7BCB8B32A718F59DEA_documentation_en-US" xlink:label="lab_clh_NumberofSitesPotentialLiabilityExceedsSubstantialQuota_1145586B72EDCA7BCB8B32A718F59DEA" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Number of Sites, Potential Liability Exceeds Substantial Quota</link:label>
    <link:loc xlink:href="clh-20171231.xsd#clh_NumberofSitesPotentialLiabilityExceedsSubstantialQuota" xlink:label="loc_clh_NumberofSitesPotentialLiabilityExceedsSubstantialQuota_1145586B72EDCA7BCB8B32A718F59DEA" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_clh_NumberofSitesPotentialLiabilityExceedsSubstantialQuota_1145586B72EDCA7BCB8B32A718F59DEA" xlink:to="lab_clh_NumberofSitesPotentialLiabilityExceedsSubstantialQuota_1145586B72EDCA7BCB8B32A718F59DEA" xlink:type="arc" />
    <link:label id="lab_clh_SiteContingencyIndemnificationAgreementNumberOfSitesOwnedByThirdParty_1C0691D7054CA3AE32E132A718F55987_terseLabel_en-US" xlink:label="lab_clh_SiteContingencyIndemnificationAgreementNumberOfSitesOwnedByThirdParty_1C0691D7054CA3AE32E132A718F55987" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Indemnification agreement with third party sites, sites</link:label>
    <link:label id="lab_clh_SiteContingencyIndemnificationAgreementNumberOfSitesOwnedByThirdParty_1C0691D7054CA3AE32E132A718F55987_label_en-US" xlink:label="lab_clh_SiteContingencyIndemnificationAgreementNumberOfSitesOwnedByThirdParty_1C0691D7054CA3AE32E132A718F55987" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Site Contingency, Indemnification Agreement Number of Sites Owned by Third Party</link:label>
    <link:label id="lab_clh_SiteContingencyIndemnificationAgreementNumberOfSitesOwnedByThirdParty_1C0691D7054CA3AE32E132A718F55987_documentation_en-US" xlink:label="lab_clh_SiteContingencyIndemnificationAgreementNumberOfSitesOwnedByThirdParty_1C0691D7054CA3AE32E132A718F55987" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">The number of sites for which the company has an indemnification agreement from the third party seller.</link:label>
    <link:loc xlink:href="clh-20171231.xsd#clh_SiteContingencyIndemnificationAgreementNumberOfSitesOwnedByThirdParty" xlink:label="loc_clh_SiteContingencyIndemnificationAgreementNumberOfSitesOwnedByThirdParty_1C0691D7054CA3AE32E132A718F55987" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_clh_SiteContingencyIndemnificationAgreementNumberOfSitesOwnedByThirdParty_1C0691D7054CA3AE32E132A718F55987" xlink:to="lab_clh_SiteContingencyIndemnificationAgreementNumberOfSitesOwnedByThirdParty_1C0691D7054CA3AE32E132A718F55987" xlink:type="arc" />
    <link:label id="lab_clh_SiteContingencyNoticeReceivedNumberOfSitesOwnedByThirdParty_4A96FBFE1BD2C12B6CBE32A718F5DF71_terseLabel_en-US" xlink:label="lab_clh_SiteContingencyNoticeReceivedNumberOfSitesOwnedByThirdParty_4A96FBFE1BD2C12B6CBE32A718F5DF71" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Notices received from owners of third party sites seeking indemnification from the company</link:label>
    <link:label id="lab_clh_SiteContingencyNoticeReceivedNumberOfSitesOwnedByThirdParty_4A96FBFE1BD2C12B6CBE32A718F5DF71_label_en-US" xlink:label="lab_clh_SiteContingencyNoticeReceivedNumberOfSitesOwnedByThirdParty_4A96FBFE1BD2C12B6CBE32A718F5DF71" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Site Contingency, Notice Received Number of Sites Owned by Third Party</link:label>
    <link:label id="lab_clh_SiteContingencyNoticeReceivedNumberOfSitesOwnedByThirdParty_4A96FBFE1BD2C12B6CBE32A718F5DF71_documentation_en-US" xlink:label="lab_clh_SiteContingencyNoticeReceivedNumberOfSitesOwnedByThirdParty_4A96FBFE1BD2C12B6CBE32A718F5DF71" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">The number of notices received from owners of third party sites related to the CSD assets seeking indemnification from the company.</link:label>
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    <link:label id="lab_clh_CreditAvailableSubjecttoPercentageofCashDeposited_FFCAFDE3D8247DC63F06D9A8D032C511_terseLabel_en-US" xlink:label="lab_clh_CreditAvailableSubjecttoPercentageofCashDeposited_FFCAFDE3D8247DC63F06D9A8D032C511" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Credit available subject to percentage of cash deposited</link:label>
    <link:label id="lab_clh_CreditAvailableSubjecttoPercentageofCashDeposited_FFCAFDE3D8247DC63F06D9A8D032C511_label_en-US" xlink:label="lab_clh_CreditAvailableSubjecttoPercentageofCashDeposited_FFCAFDE3D8247DC63F06D9A8D032C511" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Credit Available Subject to Percentage of Cash Deposited</link:label>
    <link:label id="lab_clh_CreditAvailableSubjecttoPercentageofCashDeposited_FFCAFDE3D8247DC63F06D9A8D032C511_documentation_en-US" xlink:label="lab_clh_CreditAvailableSubjecttoPercentageofCashDeposited_FFCAFDE3D8247DC63F06D9A8D032C511" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Credit Available Subject to Percentage of Cash Deposited</link:label>
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    <link:label id="lab_clh_DebtInstrumentSpreadonVariableRatePeriodforMeasurementofAverageLiquidity_D140FEB3207C2E6323FAD9A8D032AB2F_terseLabel_en-US" xlink:label="lab_clh_DebtInstrumentSpreadonVariableRatePeriodforMeasurementofAverageLiquidity_D140FEB3207C2E6323FAD9A8D032AB2F" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Period for measurement of average liquidity</link:label>
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    <link:loc xlink:href="clh-20171231.xsd#clh_DebtInstrumentSpreadonVariableRatePeriodforMeasurementofAverageLiquidity" xlink:label="loc_clh_DebtInstrumentSpreadonVariableRatePeriodforMeasurementofAverageLiquidity_D140FEB3207C2E6323FAD9A8D032AB2F" xlink:type="locator" />
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    <link:label id="lab_us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity_7E8DCB9D36BFBE7BB799D9A8D0328638_terseLabel_en-US" xlink:label="lab_us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity_7E8DCB9D36BFBE7BB799D9A8D0328638" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Revolving credit facility, available borrowing capacity</link:label>
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    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity" xlink:label="loc_us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity_7E8DCB9D36BFBE7BB799D9A8D0328638" xlink:type="locator" />
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    <link:label id="lab_us-gaap_LineOfCreditFacilityCommitmentFeePercentage_9E739A08FE211522FAB7D9A8D0329E84_terseLabel_en-US" xlink:label="lab_us-gaap_LineOfCreditFacilityCommitmentFeePercentage_9E739A08FE211522FAB7D9A8D0329E84" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Commitment fee</link:label>
    <link:label id="lab_us-gaap_LineOfCreditFacilityCommitmentFeePercentage_9E739A08FE211522FAB7D9A8D0329E84_label_en-US" xlink:label="lab_us-gaap_LineOfCreditFacilityCommitmentFeePercentage_9E739A08FE211522FAB7D9A8D0329E84" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Line of Credit Facility, Commitment Fee Percentage</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LineOfCreditFacilityCommitmentFeePercentage" xlink:label="loc_us-gaap_LineOfCreditFacilityCommitmentFeePercentage_9E739A08FE211522FAB7D9A8D0329E84" xlink:type="locator" />
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    <link:label id="lab_us-gaap_LettersOfCreditOutstandingAmount_7405AB69D10EAA631052D9A8D0321E42_terseLabel_en-US" xlink:label="lab_us-gaap_LettersOfCreditOutstandingAmount_7405AB69D10EAA631052D9A8D0321E42" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Letters of credit outstanding, amount</link:label>
    <link:label id="lab_us-gaap_LettersOfCreditOutstandingAmount_7405AB69D10EAA631052D9A8D0321E42_label_en-US" xlink:label="lab_us-gaap_LettersOfCreditOutstandingAmount_7405AB69D10EAA631052D9A8D0321E42" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Letters of Credit Outstanding, Amount</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LettersOfCreditOutstandingAmount" xlink:label="loc_us-gaap_LettersOfCreditOutstandingAmount_7405AB69D10EAA631052D9A8D0321E42" xlink:type="locator" />
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    <link:label id="lab_us-gaap_DebtInstrumentRepurchasedFaceAmount_84079A873B8CC6689706D9A8D0324ABC_terseLabel_en-US" xlink:label="lab_us-gaap_DebtInstrumentRepurchasedFaceAmount_84079A873B8CC6689706D9A8D0324ABC" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Amount used to repurchase notes</link:label>
    <link:label id="lab_us-gaap_DebtInstrumentRepurchasedFaceAmount_84079A873B8CC6689706D9A8D0324ABC_label_en-US" xlink:label="lab_us-gaap_DebtInstrumentRepurchasedFaceAmount_84079A873B8CC6689706D9A8D0324ABC" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Debt Instrument, Repurchased Face Amount</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentRepurchasedFaceAmount" xlink:label="loc_us-gaap_DebtInstrumentRepurchasedFaceAmount_84079A873B8CC6689706D9A8D0324ABC" xlink:type="locator" />
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    <link:label id="lab_us-gaap_InterestPaid_5B9D0C0A9D3ABAA07F01D9A8D0329992_terseLabel_en-US" xlink:label="lab_us-gaap_InterestPaid_5B9D0C0A9D3ABAA07F01D9A8D0329992" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Accrued interest paid</link:label>
    <link:label id="lab_us-gaap_InterestPaid_5B9D0C0A9D3ABAA07F01D9A8D0329992_label_en-US" xlink:label="lab_us-gaap_InterestPaid_5B9D0C0A9D3ABAA07F01D9A8D0329992" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Interest Paid</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_InterestPaid" xlink:label="loc_us-gaap_InterestPaid_5B9D0C0A9D3ABAA07F01D9A8D0329992" xlink:type="locator" />
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    <link:label id="lab_us-gaap_PaymentsOfDebtExtinguishmentCosts_FAC52E069F60CAC57A39D9A8D0326FE8_terseLabel_en-US" xlink:label="lab_us-gaap_PaymentsOfDebtExtinguishmentCosts_FAC52E069F60CAC57A39D9A8D0326FE8" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Premiums to repay debt early</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PaymentsOfDebtExtinguishmentCosts" xlink:label="loc_us-gaap_PaymentsOfDebtExtinguishmentCosts_FAC52E069F60CAC57A39D9A8D0326FE8" xlink:type="locator" />
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    <link:label id="lab_us-gaap_DebtIssuanceCostsIncurredDuringNoncashOrPartialNoncashTransaction_76DF14D455287863DCA7D9A8D032E794_terseLabel_en-US" xlink:label="lab_us-gaap_DebtIssuanceCostsIncurredDuringNoncashOrPartialNoncashTransaction_76DF14D455287863DCA7D9A8D032E794" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Expenses incurred from financing</link:label>
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    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtIssuanceCostsIncurredDuringNoncashOrPartialNoncashTransaction" xlink:label="loc_us-gaap_DebtIssuanceCostsIncurredDuringNoncashOrPartialNoncashTransaction_76DF14D455287863DCA7D9A8D032E794" xlink:type="locator" />
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    <link:label id="lab_us-gaap_CustomerRelationshipsMember_3184C14A2B21742BDFA5BE2CAD257AD4_verboseLabel_en-US" xlink:label="lab_us-gaap_CustomerRelationshipsMember_3184C14A2B21742BDFA5BE2CAD257AD4" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Customer and supplier relationships</link:label>
    <link:label id="lab_us-gaap_CustomerRelationshipsMember_3184C14A2B21742BDFA5BE2CAD257AD4_label_en-US" xlink:label="lab_us-gaap_CustomerRelationshipsMember_3184C14A2B21742BDFA5BE2CAD257AD4" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Customer Relationships [Member]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CustomerRelationshipsMember" xlink:label="loc_us-gaap_CustomerRelationshipsMember_3184C14A2B21742BDFA5BE2CAD257AD4" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CustomerRelationshipsMember_3184C14A2B21742BDFA5BE2CAD257AD4" xlink:to="lab_us-gaap_CustomerRelationshipsMember_3184C14A2B21742BDFA5BE2CAD257AD4" xlink:type="arc" />
    <link:label id="lab_clh_FiniteLivedTotalMember_960386DEFD1880BEE5F8BE2CAD250095_terseLabel_en-US" xlink:label="lab_clh_FiniteLivedTotalMember_960386DEFD1880BEE5F8BE2CAD250095" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Total amortizable permits and other intangible assets</link:label>
    <link:label id="lab_clh_FiniteLivedTotalMember_960386DEFD1880BEE5F8BE2CAD250095_label_en-US" xlink:label="lab_clh_FiniteLivedTotalMember_960386DEFD1880BEE5F8BE2CAD250095" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Finite Lived Total [Member]</link:label>
    <link:label id="lab_clh_FiniteLivedTotalMember_960386DEFD1880BEE5F8BE2CAD250095_documentation_en-US" xlink:label="lab_clh_FiniteLivedTotalMember_960386DEFD1880BEE5F8BE2CAD250095" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Finite Lived Total [Member]</link:label>
    <link:loc xlink:href="clh-20171231.xsd#clh_FiniteLivedTotalMember" xlink:label="loc_clh_FiniteLivedTotalMember_960386DEFD1880BEE5F8BE2CAD250095" xlink:type="locator" />
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    <link:label id="lab_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis_3A46E9E6E5F16D24AA37BE2CAD25309F_terseLabel_en-US" xlink:label="lab_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis_3A46E9E6E5F16D24AA37BE2CAD25309F" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Indefinite-lived Intangible Assets by Major Class [Axis]</link:label>
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    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis" xlink:label="loc_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis_3A46E9E6E5F16D24AA37BE2CAD25309F" xlink:type="locator" />
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    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:label="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_89D1C4A67491AA712960BE2CAD2539F2" xlink:type="locator" />
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    <link:label id="lab_us-gaap_TrademarksMember_906F7E7F574AD8ADDB21BE2CAD25D8A9_terseLabel_en-US" xlink:label="lab_us-gaap_TrademarksMember_906F7E7F574AD8ADDB21BE2CAD25D8A9" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Trademarks and trade names</link:label>
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    <link:label id="lab_us-gaap_IntangibleAssetsGrossExcludingGoodwill_DD46D6A444EAC1B66CFBBE2CAD255AE9_terseLabel_en-US" xlink:label="lab_us-gaap_IntangibleAssetsGrossExcludingGoodwill_DD46D6A444EAC1B66CFBBE2CAD255AE9" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Total permits and other intangible assets, cost</link:label>
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    <link:label id="lab_us-gaap_AssetRetirementObligationCostsMember_D40D758E84BD795A3E5D32A718D4F26D_terseLabel_en-US" xlink:label="lab_us-gaap_AssetRetirementObligationCostsMember_D40D758E84BD795A3E5D32A718D4F26D" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Asset retirement costs (non-landfill)</link:label>
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