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  <xs:element id="clh_CashAndCashEquivalentsBankDisbursementAccountMinimumBalanceAllowed" abstract="false" name="CashAndCashEquivalentsBankDisbursementAccountMinimumBalanceAllowed" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
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  <xs:element id="clh_HydroChemPSCMember" abstract="true" name="HydroChemPSCMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
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</xs:schema>
