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  <xsd:element abstract="true" id="clh_DenominatorForBasicAndDilutedEarningsPerShareAbstract" name="DenominatorForBasicAndDilutedEarningsPerShareAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_DiscountReserves" name="DiscountReserves" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="clh_DistributionsEarnedOnEmployeeParticipationPlan" name="DistributionsEarnedOnEmployeeParticipationPlan" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element id="clh_DividendsPaidReceived" name="DividendsPaidReceived" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_DocumentAndEntityInformationAbstract" name="DocumentAndEntityInformationAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_EffectiveIncomeTaxRate" name="EffectiveIncomeTaxRate" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_EmployeeStockPurchasePlan2005Member" name="EmployeeStockPurchasePlan2005Member" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_EnergyRelatedInventoryOther" name="EnergyRelatedInventoryOther" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="clh_EnergyRelatedInventorySuppliesAndDrums" name="EnergyRelatedInventorySuppliesAndDrums" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element abstract="true" id="clh_EnvironmentalContingenciesTable" name="EnvironmentalContingenciesTable" nillable="true" substitutionGroup="xbrldt:hypercubeItem" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_EnvironmentalServicesMember" name="EnvironmentalServicesMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_EvergreenOilIncMember" name="EvergreenOilIncMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_ExpirationOfVariousStateStatuteOfLimitation" name="ExpirationOfVariousStateStatuteOfLimitation" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_ExpiringOfStatutesOfLimitationsMember" name="ExpiringOfStatutesOfLimitationsMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_ExpiringStatuteOfLimitationsRelatedToHistoricalCanadianBusinessCombination" name="ExpiringStatuteOfLimitationsRelatedToHistoricalCanadianBusinessCombination" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_FederalAndStateEnforcementActionsAbstract" name="FederalAndStateEnforcementActionsAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_FederalAndStateEnforcementActionsMember" name="FederalAndStateEnforcementActionsMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_FiniteLivedTotalMember" name="FiniteLivedTotalMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_FiniteandIndefiniteLivedIntangiblesGross" name="FiniteandIndefiniteLivedIntangiblesGross" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="clh_GainLossOnSaleOfFixedAssetsAndAssetsHeldForSale" name="GainLossOnSaleOfFixedAssetsAndAssetsHeldForSale" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_GrassyMountainMember" name="GrassyMountainMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_GuarantorAndNonGuarantorSubsidiariesFinancialInformationAbstract" name="GuarantorAndNonGuarantorSubsidiariesFinancialInformationAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_IdledIncineratorAndLegalProceedingsMember" name="IdledIncineratorAndLegalProceedingsMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_ImputedInterestMinimum" name="ImputedInterestMinimum" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_ImputedInterestRate" name="ImputedInterestRate" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="clh_ImputedInterestRateMaximum" name="ImputedInterestRateMaximum" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_InactiveLandfillFacilitiesMember" name="InactiveLandfillFacilitiesMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_IncomeLossFromAffiliatesSubsidiariesAndHoldingCompany" name="IncomeLossFromAffiliatesSubsidiariesAndHoldingCompany" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element id="clh_IncomeLossFromContinuingOperationsBeforeInterestTaxDepreciationAndAmortizationNet" name="IncomeLossFromContinuingOperationsBeforeInterestTaxDepreciationAndAmortizationNet" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element id="clh_IncreaseDecreaseTaxBenefitFromStockOptionsExercised" name="IncreaseDecreaseTaxBenefitFromStockOptionsExercised" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_IndustrialandFieldServicesMember" name="IndustrialandFieldServicesMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_InflationRate" name="InflationRate" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_IntangibleAssetsNetExcludingGoodwillPercent" name="IntangibleAssetsNetExcludingGoodwillPercent" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="instant" />
  <xsd:element id="clh_InterestExpenseNet" name="InterestExpenseNet" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element id="clh_IssuanceOfSeniorUnsecuredNotesAtPar" name="IssuanceOfSeniorUnsecuredNotesAtPar" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_KimballMember" name="KimballMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_LambtonMember" name="LambtonMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_LandFillAccountingPolicyTextBlock" name="LandFillAccountingPolicyTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_LandfillFinalClosureAndPostClosureLiabilities" name="LandfillFinalClosureAndPostClosureLiabilities" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element abstract="true" id="clh_LandfillRetirementLiabilityMember" name="LandfillRetirementLiabilityMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_LandfillSites" name="LandfillSites" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="instant" />
  <xsd:element abstract="true" id="clh_LastDayOfQuarterlyOfferingMember" name="LastDayOfQuarterlyOfferingMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_LeaseTermsRangeMaximum" name="LeaseTermsRangeMaximum" nillable="true" substitutionGroup="xbrli:item" type="xbrli:durationItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_LeaseTermsRangeMinimum" name="LeaseTermsRangeMinimum" nillable="true" substitutionGroup="xbrli:item" type="xbrli:durationItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_LegalAndAdministrativeProceedingsAbstract" name="LegalAndAdministrativeProceedingsAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_LegalAndAdministrativeProceedingsMember" name="LegalAndAdministrativeProceedingsMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_LettersOfCreditPolicyTextBlock" name="LettersOfCreditPolicyTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_LineOfCreditFacilityBorrowingCapacity" name="LineOfCreditFacilityBorrowingCapacity" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_LoneMountainMember" name="LoneMountainMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_LongLivedAssetsByNameAxis" name="LongLivedAssetsByNameAxis" nillable="true" substitutionGroup="xbrldt:dimensionItem" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_LongLivedAssetsByNameDomain" name="LongLivedAssetsByNameDomain" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_LongTermDebtRedemptionPriceAsPercentageOfPrincipalAmount" name="LongTermDebtRedemptionPriceAsPercentageOfPrincipalAmount" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_LongTermDebtRedemptionPriceDuringTwelveMonthPeriodYear1AsPercentageOfPrincipalAmount" name="LongTermDebtRedemptionPriceDuringTwelveMonthPeriodYear1AsPercentageOfPrincipalAmount" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_LongTermDebtRedemptionPriceDuringTwelveMonthPeriodYear2AsPercentageOfPrincipalAmount" name="LongTermDebtRedemptionPriceDuringTwelveMonthPeriodYear2AsPercentageOfPrincipalAmount" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_LongTermDebtRedemptionPriceDuringTwelvesYear3AndThereafterAsPercentageOfPrincipalAmount" name="LongTermDebtRedemptionPriceDuringTwelvesYear3AndThereafterAsPercentageOfPrincipalAmount" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_LongTermDebtRedemptionPriceWithNetProceedsFromEquityOfferingsAsPercentageOfPrincipalAmount" name="LongTermDebtRedemptionPriceWithNetProceedsFromEquityOfferingsAsPercentageOfPrincipalAmount" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_LongTermDebtRedemptionWithNetProceedsFromEquityOfferingsAsPercentageOfPrincipalAmount" name="LongTermDebtRedemptionWithNetProceedsFromEquityOfferingsAsPercentageOfPrincipalAmount" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_LossContingencyAccrualAtCarryingValuePotentialAdditionalLiability" name="LossContingencyAccrualAtCarryingValuePotentialAdditionalLiability" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element id="clh_LossContingencyGeneralDamagesSoughtValue" name="LossContingencyGeneralDamagesSoughtValue" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element id="clh_LossContingencyNumberofCustomersFilingComplaint" name="LossContingencyNumberofCustomersFilingComplaint" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_LossContingencyPunitiveDamagesSoughtValue" name="LossContingencyPunitiveDamagesSoughtValue" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element id="clh_LossContingencyRangeOfLoss" name="LossContingencyRangeOfLoss" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element abstract="true" id="clh_MercierQuebecMember" name="MercierQuebecMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_NetDividendIncomeFromAffiliatesSubsidiariesAndHoldingCompany" name="NetDividendIncomeFromAffiliatesSubsidiariesAndHoldingCompany" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element id="clh_NetInterestIncomeFromAffiliatesSubsidiariesAndHoldingCompany" name="NetInterestIncomeFromAffiliatesSubsidiariesAndHoldingCompany" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_NonCommercialLandfillsMember" name="NonCommercialLandfillsMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_NonLandfillClosureAndPostClosureLiabilities" name="NonLandfillClosureAndPostClosureLiabilities" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="clh_NonLandfillClosureAndPostClosureLiabilitiesPolicyTextBlock" name="NonLandfillClosureAndPostClosureLiabilitiesPolicyTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_NonLandfillClosureAndPostClosureTermInYears" name="NonLandfillClosureAndPostClosureTermInYears" nillable="true" substitutionGroup="xbrli:item" type="xbrli:durationItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_NonLandfillRetirementLiabilityMember" name="NonLandfillRetirementLiabilityMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_NoncashAcquisitionAccountingAdjustmentsBeforeTax" name="NoncashAcquisitionAccountingAdjustmentsBeforeTax" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element id="clh_NumberOfActiveNonSupervisoryCanadianEmployees" name="NumberOfActiveNonSupervisoryCanadianEmployees" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="instant" />
  <xsd:element id="clh_NumberOfExpansions" name="NumberOfExpansions" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="instant" />
  <xsd:element id="clh_NumberOfFacilityByType" name="NumberOfFacilityByType" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="instant" />
  <xsd:element id="clh_NumberOfNeighboringMunicipalitiesFilingSeparateLegalProceedings" name="NumberOfNeighboringMunicipalitiesFilingSeparateLegalProceedings" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_NumberOfOperationsNotManagedByReportableSegments" name="NumberOfOperationsNotManagedByReportableSegments" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_NumberOfPermitsIssuedByGovernmentToDumpOrganicLiquid" name="NumberOfPermitsIssuedByGovernmentToDumpOrganicLiquid" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_NumberOfServiceLocationsWithUnpermittedExpansion" name="NumberOfServiceLocationsWithUnpermittedExpansion" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="instant" />
  <xsd:element id="clh_NumberOfSites" name="NumberOfSites" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_NumberofPerformanceCriteria" name="NumberofPerformanceCriteria" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_NumberofReportingUnits" name="NumberofReportingUnits" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="instant" />
  <xsd:element id="clh_NumberofSitesPotentialLiabilityExceedsSubstantialQuota" name="NumberofSitesPotentialLiabilityExceedsSubstantialQuota" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_NumeratorForBasicAndDilutedEarningsPerShareAbstract" name="NumeratorForBasicAndDilutedEarningsPerShareAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_OilAndGasFieldServicesMember" name="OilAndGasFieldServicesMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_OilRefiningandRecyclingSegmentMember" name="OilRefiningandRecyclingSegmentMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_OperationsLineItems" name="OperationsLineItems" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_OperationsTable" name="OperationsTable" nillable="true" substitutionGroup="xbrldt:hypercubeItem" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_Other2012AcquisitionsMember" name="Other2012AcquisitionsMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_OtherInternationalLocationsMember" name="OtherInternationalLocationsMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_OtherLiabilitesAbstract" name="OtherLiabilitesAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_PartsCleaningServicesMember" name="PartsCleaningServicesMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_PayablesToAffiliatesSubsidiariesAndHoldingCompanies" name="PayablesToAffiliatesSubsidiariesAndHoldingCompanies" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="clh_PaymentsForProceedsFromInterest" name="PaymentsForProceedsFromInterest" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element id="clh_PayrollDeductionToPurchaseCommonStock" name="PayrollDeductionToPurchaseCommonStock" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_PeakEnergyServicesLtdSPeakMember" name="PeakEnergyServicesLtdSPeakMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_PercentageFairValueExceededCarryingValue" name="PercentageFairValueExceededCarryingValue" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="instant" />
  <xsd:element id="clh_PercentageOfAggregatePrincipleOfDebt" name="PercentageOfAggregatePrincipleOfDebt" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_PercentageOfAirspaceRemaining" name="PercentageOfAirspaceRemaining" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="instant" />
  <xsd:element id="clh_PerformanceEvaluationStockBasedCompensation" name="PerformanceEvaluationStockBasedCompensation" nillable="true" substitutionGroup="xbrli:item" type="xbrli:durationItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_PerformanceStockAwardsMember" name="PerformanceStockAwardsMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_PeriodOfTimeInYearsOverWhichBusinessAcquisitionsHaveBeenAcquired" name="PeriodOfTimeInYearsOverWhichBusinessAcquisitionsHaveBeenAcquired" nillable="true" substitutionGroup="xbrli:item" type="xbrli:durationItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_PermitsMember" name="PermitsMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_PermittedButNotHighlyProbableAirspace" name="PermittedButNotHighlyProbableAirspace" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="instant" />
  <xsd:element abstract="true" id="clh_PermittedMember" name="PermittedMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_PossibleIncreaseInTotalRemedialLiabilities" name="PossibleIncreaseInTotalRemedialLiabilities" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element id="clh_PrepaidExpensesAndOtherAssetsCurrent" name="PrepaidExpensesAndOtherAssetsCurrent" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element abstract="true" id="clh_PriorLineOfCreditMember" name="PriorLineOfCreditMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_ProbableAirspace" name="ProbableAirspace" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="instant" />
  <xsd:element id="clh_ProceedsFromIntercompanyDebt" name="ProceedsFromIntercompanyDebt" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element id="clh_ProceedsFromSalesOfFixedAssetsAndAssetsHeldForSale" name="ProceedsFromSalesOfFixedAssetsAndAssetsHeldForSale" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element id="clh_PropertyPlantAndEquipmentNetPercent" name="PropertyPlantAndEquipmentNetPercent" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="instant" />
  <xsd:element abstract="true" id="clh_QuarterlyDataUnauditedTable" name="QuarterlyDataUnauditedTable" nillable="true" substitutionGroup="xbrldt:hypercubeItem" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_QuarterlyDataUnauditedTableTextBlock" name="QuarterlyDataUnauditedTableTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_QuarterlyLineItems" name="QuarterlyLineItems" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_QuarterlyOfferingsOfShares" name="QuarterlyOfferingsOfShares" nillable="true" substitutionGroup="xbrli:item" type="xbrli:sharesItemType" xbrli:periodType="instant" />
  <xsd:element id="clh_ReceivablesFromAffiliatesSubsidiariesAndHoldingCompanies" name="ReceivablesFromAffiliatesSubsidiariesAndHoldingCompanies" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element abstract="true" id="clh_ReconciliationOfNetIncomeToAdjustedEbitdaAbstract" name="ReconciliationOfNetIncomeToAdjustedEbitdaAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_RecordableWorkplaceInjuryRate" name="RecordableWorkplaceInjuryRate" nillable="true" substitutionGroup="xbrli:item" type="xbrli:pureItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_RedeemableDebtRedemptionAxis" name="RedeemableDebtRedemptionAxis" nillable="true" substitutionGroup="xbrldt:dimensionItem" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_RedeemableDebtRedemptionDomain" name="RedeemableDebtRedemptionDomain" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_RedeemableDebtRedemptionRateOf107625PercentMember" name="RedeemableDebtRedemptionRateOf107625PercentMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_RegulatoryPostClosurePeriodForLandfill" name="RegulatoryPostClosurePeriodForLandfill" nillable="true" substitutionGroup="xbrli:item" type="xbrli:durationItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_RemainingAirspaceCapacityRollForward" name="RemainingAirspaceCapacityRollForward" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_RemainingHighlyProbableAirspace" name="RemainingHighlyProbableAirspace" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_RemainingHighlyProbableAirspaceTableTextBlock" name="RemainingHighlyProbableAirspaceTableTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_RemedialLiabilitiesAnticipatedPaymentsForEachOfNextFiveYearsTableTextBlock" name="RemedialLiabilitiesAnticipatedPaymentsForEachOfNextFiveYearsTableTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_RemedialLiabilitiesDiscountedRiskFreeInterestRate" name="RemedialLiabilitiesDiscountedRiskFreeInterestRate" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_RemedialLiabilitiesForInactiveSitesMember" name="RemedialLiabilitiesForInactiveSitesMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_RemedialLiabilitiesForLandfillSitesMember" name="RemedialLiabilitiesForLandfillSitesMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_RemedialLiabilitiesIncludingSuperfundForNonLandfillOperationsMember" name="RemedialLiabilitiesIncludingSuperfundForNonLandfillOperationsMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_RemedialLiabilitiesInflationRateatAcquisition" name="RemedialLiabilitiesInflationRateatAcquisition" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_RepaymentOfCapitalLeaseObligation" name="RepaymentOfCapitalLeaseObligation" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element id="clh_ReportingSegmentsNumber" name="ReportingSegmentsNumber" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_ReservesToBeProvidedOverRemainingSiteLives" name="ReservesToBeProvidedOverRemainingSiteLives" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="clh_RetentionforEnvironmentalImpairment" name="RetentionforEnvironmentalImpairment" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_RyleyMember" name="RyleyMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_SafetyKleenMember" name="SafetyKleenMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_SawyerMember" name="SawyerMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_ScheduleOfCondensedConsolidatingBalanceSheetTableTextBlock" name="ScheduleOfCondensedConsolidatingBalanceSheetTableTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_ScheduleOfCondensedConsolidatingStatementOfCashFlowsTableTextBlock" name="ScheduleOfCondensedConsolidatingStatementOfCashFlowsTableTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_ScheduleOfCondensedConsolidatingStatementOfOperationsTableTextBlock" name="ScheduleOfCondensedConsolidatingStatementOfOperationsTableTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_ScheduleOfDebtInstrumentRedemptionPriceTableTextBlock" name="ScheduleOfDebtInstrumentRedemptionPriceTableTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_ScheduleOfExpectedPaymentsRelatedToAssetRetirementObligationsTableTextBlock" name="ScheduleOfExpectedPaymentsRelatedToAssetRetirementObligationsTableTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_ScheduleOfPropertyPlantAndEquipmentLandfillAssetsTableTextBlock" name="ScheduleOfPropertyPlantAndEquipmentLandfillAssetsTableTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_ScheduleOfReconciliationOfNetIncomeToAdjustedEarningsBeforeInterestTaxDepreciationAndAmortizationConsolidatedTableTextBlock" name="ScheduleOfReconciliationOfNetIncomeToAdjustedEarningsBeforeInterestTaxDepreciationAndAmortizationConsolidatedTableTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_ScheduleOfSegmentPpeAndIntangibleAssetsTableTextBlock" name="ScheduleOfSegmentPpeAndIntangibleAssetsTableTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_ScheduleOfSegmentRevenuesTableTextBlock" name="ScheduleOfSegmentRevenuesTableTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_ScheduleOfSegmentTotalAssetsTableTextBlock" name="ScheduleOfSegmentTotalAssetsTableTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_ScheduleOfTotalAssetsByGeographicalAreaTableTextBlock" name="ScheduleOfTotalAssetsByGeographicalAreaTableTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_ScheduleofFutureMinimumLeasePaymentsforCapitalLeasesandOperatingLeasesTableTextBlock" name="ScheduleofFutureMinimumLeasePaymentsforCapitalLeasesandOperatingLeasesTableTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_SecuredSeniorNotes2016Member" name="SecuredSeniorNotes2016Member" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_SegmentReportingInformationRevenuePercent" name="SegmentReportingInformationRevenuePercent" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_SelfInsuranceDiscountRate" name="SelfInsuranceDiscountRate" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="clh_SelfInsuranceLiabilities" name="SelfInsuranceLiabilities" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element id="clh_SelfInsuranceLiabilitiesAnticipatedPaymentsTableTextBlock" name="SelfInsuranceLiabilitiesAnticipatedPaymentsTableTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_ShareBasedCompensationArrangementByShareBasedPaymentAwardAdditionalSharesAuthorized" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardAdditionalSharesAuthorized" nillable="true" substitutionGroup="xbrli:item" type="xbrli:sharesItemType" xbrli:periodType="instant" />
  <xsd:element id="clh_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedForfeitureRateEmployees" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedForfeitureRateEmployees" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_SharebasedCompensationArrangementbySharebasedPaymentAwardFairValueAssumptionsExpectedForfeitureRateExecutivesandDirectors" name="SharebasedCompensationArrangementbySharebasedPaymentAwardFairValueAssumptionsExpectedForfeitureRateExecutivesandDirectors" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_SharesHeldUnderEmployeeParticipationPlan" name="SharesHeldUnderEmployeeParticipationPlan" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_SharesHeldUnderEmployeeParticipationPlanMember" name="SharesHeldUnderEmployeeParticipationPlanMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_SignificantAccountingPoliciesAndRecentAccountingPronouncementsTextBlock" name="SignificantAccountingPoliciesAndRecentAccountingPronouncementsTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_SiteContingencyAreaAcquiredbyEntity" name="SiteContingencyAreaAcquiredbyEntity" nillable="true" substitutionGroup="xbrli:item" type="num:areaItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_SiteContingencyCleanupCostsNumberOfSitesOwnedByThirdParty" name="SiteContingencyCleanupCostsNumberOfSitesOwnedByThirdParty" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_SiteContingencyEnvironmentalRemediationExpenseNumberOfSitesOwnedByThirdParty" name="SiteContingencyEnvironmentalRemediationExpenseNumberOfSitesOwnedByThirdParty" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_SiteContingencyEnvironmentalRemediationExpenseSettledNumberOfSitesOwnedByThirdParty" name="SiteContingencyEnvironmentalRemediationExpenseSettledNumberOfSitesOwnedByThirdParty" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_SiteContingencyIndemnificationAgreementNumberOfSitesOwnedByThirdParty" name="SiteContingencyIndemnificationAgreementNumberOfSitesOwnedByThirdParty" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_SiteContingencyNotRequiringEnvironmentalRemediationExpenseNumberOfSitesOwnedByThirdParty" name="SiteContingencyNotRequiringEnvironmentalRemediationExpenseNumberOfSitesOwnedByThirdParty" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_SiteContingencyNoticeReceivedNumberOfSitesOwnedByThirdParty" name="SiteContingencyNoticeReceivedNumberOfSitesOwnedByThirdParty" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_SiteContingencyNumberOfSites" name="SiteContingencyNumberOfSites" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_SiteContingencyNumberOfSitesOwnedByEntity" name="SiteContingencyNumberOfSitesOwnedByEntity" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_SiteContingencyNumberOfSitesOwnedByThirdParty" name="SiteContingencyNumberOfSitesOwnedByThirdParty" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_SolarEquipmentMember" name="SolarEquipmentMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_StockIssuedDuringPeriodPerShareValueNewIssues" name="StockIssuedDuringPeriodPerShareValueNewIssues" nillable="true" substitutionGroup="xbrli:item" type="num:perShareItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_SuperfundLandfillSitesOwnedByThirdPartiesMember" name="SuperfundLandfillSitesOwnedByThirdPartiesMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_SuperfundProceedingsAbstract" name="SuperfundProceedingsAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_SuperfundProceedingsMember" name="SuperfundProceedingsMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_TechnicalServicesFieldServicesIndustrialServicesandLodgingSegmentsMember" name="TechnicalServicesFieldServicesIndustrialServicesandLodgingSegmentsMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_TechnicalServicesMember" name="TechnicalServicesMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_ThirdQuarter2011AcquisitionsMember" name="ThirdQuarter2011AcquisitionsMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_TransferofInventorytoPropertyPlantandEquipment" name="TransferofInventorytoPropertyPlantandEquipment" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element id="clh_UnbilledAccountsReceivableCurrent" name="UnbilledAccountsReceivableCurrent" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="clh_UncertainTaxPositionInterestAndPenaltiesNetOfBenefit" name="UncertainTaxPositionInterestAndPenaltiesNetOfBenefit" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element id="clh_UncertainTaxPositionReleasesNetOfBenefit" name="UncertainTaxPositionReleasesNetOfBenefit" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element id="clh_UndiscountedClosureAndPostClosureLiabilities" name="UndiscountedClosureAndPostClosureLiabilities" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="clh_UndiscountedSelfInsuranceLiabilities" name="UndiscountedSelfInsuranceLiabilities" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element abstract="true" id="clh_UnitedStatesAndPuertoRicoMember" name="UnitedStatesAndPuertoRicoMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_UnitedStatesDefinedContributionPlanMember" name="UnitedStatesDefinedContributionPlanMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_UnpermittedMember" name="UnpermittedMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_UnrecognizedTaxBenefitsAndOtherLongTermLiabilitiesNoncurrent" name="UnrecognizedTaxBenefitsAndOtherLongTermLiabilitiesNoncurrent" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="clh_UnrecognizedTaxBenefitsIncludingInterestAndPenalties" name="UnrecognizedTaxBenefitsIncludingInterestAndPenalties" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element abstract="true" id="clh_UnsecuredSeniorNotes2020Member" name="UnsecuredSeniorNotes2020Member" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_UnsecuredSeniorNotes2021Member" name="UnsecuredSeniorNotes2021Member" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_ValuationAllowanceAmountDeferredTaxAssetsofSubsidiary" name="ValuationAllowanceAmountDeferredTaxAssetsofSubsidiary" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="clh_ValuationAllowanceAmountForeignNetOperatingLoss" name="ValuationAllowanceAmountForeignNetOperatingLoss" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="clh_ValuationAllowanceAmountForeignTaxCredits" name="ValuationAllowanceAmountForeignTaxCredits" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="clh_ValuationAllowanceAmountStateNetOperatingLoss" name="ValuationAllowanceAmountStateNetOperatingLoss" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element abstract="true" id="clh_VariousMember" name="VariousMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_VilleMercierMember" name="VilleMercierMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_WeightedAveragePerShareFairValuesOfPurchaseRights" name="WeightedAveragePerShareFairValuesOfPurchaseRights" nillable="true" substitutionGroup="xbrli:item" type="num:perShareItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_WestmorlandMember" name="WestmorlandMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_WichitaPropertyMember" name="WichitaPropertyMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_WriteOffDeferredFinancingCostsAndDebtDiscount" name="WriteOffDeferredFinancingCostsAndDebtDiscount" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_YellowstoneRiverMember" name="YellowstoneRiverMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
</xsd:schema>