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  <xsd:element id="wlk_BusinessCombinationCashDepositedInEscrow" name="BusinessCombinationCashDepositedInEscrow" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element id="wlk_BusinessCombinationNetPreexistingBalancesBetweenAcquirerAndAcquiree" name="BusinessCombinationNetPreexistingBalancesBetweenAcquirerAndAcquiree" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element id="wlk_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNotesPayableToBank" name="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNotesPayableToBank" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="wlk_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedWorkingCapitalExcludingInventoryAndCash" name="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedWorkingCapitalExcludingInventoryAndCash" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="wlk_BusinessCombinationRecognizedIdentifiableAssetsAcquiredandLiabilitiesAssumedCurrentAssetsReceivablesGrossContractualAmount" name="BusinessCombinationRecognizedIdentifiableAssetsAcquiredandLiabilitiesAssumedCurrentAssetsReceivablesGrossContractualAmount" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="wlk_BusinessCombinationRecognizedIdentifiableAssetsAcquiredandLiabilitiesAssumedCurrentAssetsUncollectableReceivables" name="BusinessCombinationRecognizedIdentifiableAssetsAcquiredandLiabilitiesAssumedCurrentAssetsUncollectableReceivables" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="wlk_BusinessCombinationRecognizedIdentifiableAssetsAcquiredandLiabilitiesAssumedCurrentLiabilitiesPowerPurchaseAgreementLiability" name="BusinessCombinationRecognizedIdentifiableAssetsAcquiredandLiabilitiesAssumedCurrentLiabilitiesPowerPurchaseAgreementLiability" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="wlk_BusinessCombinationRecognizedIdentifiableAssetsAcquiredandLiabilitiesAssumedInventoryAdjustment" name="BusinessCombinationRecognizedIdentifiableAssetsAcquiredandLiabilitiesAssumedInventoryAdjustment" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="wlk_BusinessCombinationRecognizedIdentifiableAssetsAcquiredandLiabilitiesAssumedNoncurrentAssetsInvestments" name="BusinessCombinationRecognizedIdentifiableAssetsAcquiredandLiabilitiesAssumedNoncurrentAssetsInvestments" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="wlk_BusinessCombinationRecognizedIdentifiableAssetsAcquiredandLiabilitiesAssumedNoncurrentLiabilitiesPensionObligation" name="BusinessCombinationRecognizedIdentifiableAssetsAcquiredandLiabilitiesAssumedNoncurrentLiabilitiesPensionObligation" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="wlk_BusinessCombinationRecognizedIdentifiableAssetsAcquiredandLiabilitiesAssumedNoncurrentLiabilitiesPowerPurchaseAgreementLiabilityWeightedAverageLife" name="BusinessCombinationRecognizedIdentifiableAssetsAcquiredandLiabilitiesAssumedNoncurrentLiabilitiesPowerPurchaseAgreementLiabilityWeightedAverageLife" nillable="true" substitutionGroup="xbrli:item" type="xbrli:durationItemType" xbrli:periodType="duration" />
  <xsd:element id="wlk_BusinessCombinationRetirementOfDebtNotAssumedInAcquisition" name="BusinessCombinationRetirementOfDebtNotAssumedInAcquisition" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="wlk_CashReserveTurnaroundMember" name="CashReserveTurnaroundMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="wlk_CausticSodaMember" name="CausticSodaMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="wlk_CliffVestMember" name="CliffVestMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="wlk_CommodityForwardContractsMember" name="CommodityForwardContractsMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="wlk_CommonStockOtherRights" name="CommonStockOtherRights" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element id="wlk_CommonStockRedemptionProvision" name="CommonStockRedemptionProvision" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="wlk_CommonStockSinkingFundProvision" name="CommonStockSinkingFundProvision" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="wlk_CommonStockVotingRightsNumberofVotesPerShare" name="CommonStockVotingRightsNumberofVotesPerShare" nillable="true" substitutionGroup="xbrli:item" type="xbrli:decimalItemType" xbrli:periodType="duration" />
  <xsd:element id="wlk_ConcentrationOfCreditRiskPolicyTextBlock" name="ConcentrationOfCreditRiskPolicyTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element id="wlk_ConcentrationRiskNumberOfMajorCustomers" name="ConcentrationRiskNumberOfMajorCustomers" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="wlk_CounterpartyAMember" name="CounterpartyAMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="wlk_CounterpartyBMember" name="CounterpartyBMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="wlk_CumulativeForeignCurrencyExchangeMember" name="CumulativeForeignCurrencyExchangeMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="wlk_CypressInterstatePipelineLLCMember" name="CypressInterstatePipelineLLCMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="wlk_DebtAmountInExcessOfGuaranteedBySubsidiaries" name="DebtAmountInExcessOfGuaranteedBySubsidiaries" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element abstract="true" id="wlk_DebtCovenantMember" name="DebtCovenantMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="wlk_DebtInstrumentBasisSpreadonVariableRateMaximumProvidedCompanyRatedInvestmentGrade" name="DebtInstrumentBasisSpreadonVariableRateMaximumProvidedCompanyRatedInvestmentGrade" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="wlk_DebtInstrumentMaturity" name="DebtInstrumentMaturity" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="wlk_DebtInstrumentRedemptionPeriodEightMember" name="DebtInstrumentRedemptionPeriodEightMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="wlk_DebtInstrumentRedemptionPeriodSevenMember" name="DebtInstrumentRedemptionPeriodSevenMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="wlk_DebtInstrumentRedemptionPeriodSixMember" name="DebtInstrumentRedemptionPeriodSixMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="wlk_DebtInstrumentRepurchasePriceAsPercentageOfPrincipalAmountUponChangeOfControlAndBelowInvestmentGradeRatingEvent" name="DebtInstrumentRepurchasePriceAsPercentageOfPrincipalAmountUponChangeOfControlAndBelowInvestmentGradeRatingEvent" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="instant" />
  <xsd:element abstract="true" id="wlk_DebtIssuanceCostMember" name="DebtIssuanceCostMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="wlk_DeferredTaxLiabilitiesParentsBasisInConsolidatedPartnerships" name="DeferredTaxLiabilitiesParentsBasisInConsolidatedPartnerships" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element abstract="true" id="wlk_DeferredTurnaroundCostsMember" name="DeferredTurnaroundCostsMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="wlk_DefinedBenefitPlanAmountsRecognizedinOtherComprehensiveIncomeLossAndNetPeriodicBenefitCreditCost" name="DefinedBenefitPlanAmountsRecognizedinOtherComprehensiveIncomeLossAndNetPeriodicBenefitCreditCost" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element id="wlk_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationExpectedLongTermReturnOnAssets" name="DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationExpectedLongTermReturnOnAssets" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="wlk_DefinedBenefitPlanFundedStatusPercentage" name="DefinedBenefitPlanFundedStatusPercentage" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="wlk_DefinedBenefitPlanTargetAllocationPercentageOfAssetsDiscretionaryRange" name="DefinedBenefitPlanTargetAllocationPercentageOfAssetsDiscretionaryRange" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="wlk_DefinedBenefitPlanTargetAllocationPercentageOfAssetsLongTerm" name="DefinedBenefitPlanTargetAllocationPercentageOfAssetsLongTerm" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="wlk_DefinedBenefitPlanTargetAllocationPercentageOfAssetsShortTerm" name="DefinedBenefitPlanTargetAllocationPercentageOfAssetsShortTerm" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="wlk_DefinedContributionRetirementPlanMember" name="DefinedContributionRetirementPlanMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="wlk_DefinedContributionSavingsPlanMember" name="DefinedContributionSavingsPlanMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="wlk_DepreciationAndAmortizationIncludingAmortizationOfDebtIssuanceCosts" name="DepreciationAndAmortizationIncludingAmortizationOfDebtIssuanceCosts" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="wlk_DerivativeInstrumentsandHedgesOffsettingofDerivativeAssetsAbstract" name="DerivativeInstrumentsandHedgesOffsettingofDerivativeAssetsAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="wlk_DerivativeInstrumentsandHedgesOffsettingofDerivativeLiabilitiesAbstract" name="DerivativeInstrumentsandHedgesOffsettingofDerivativeLiabilitiesAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element id="wlk_DescriptionOfBusinessPolicyTextBlock" name="DescriptionOfBusinessPolicyTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element id="wlk_DiscountedCashFlowMethodologyAssetImpairmentNumberOfYearsForecasted" name="DiscountedCashFlowMethodologyAssetImpairmentNumberOfYearsForecasted" nillable="true" substitutionGroup="xbrli:item" type="xbrli:durationItemType" xbrli:periodType="duration" />
  <xsd:element id="wlk_DiscountedCashFlowMethodologyGoodwillImpairmentCashFlowPercentageDecreaseWithoutImpairment" name="DiscountedCashFlowMethodologyGoodwillImpairmentCashFlowPercentageDecreaseWithoutImpairment" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="wlk_DiscountedCashFlowMethodologyGoodwillImpairmentDiscountRate" name="DiscountedCashFlowMethodologyGoodwillImpairmentDiscountRate" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="wlk_DiscountedCashFlowProjectionsPeriod" name="DiscountedCashFlowProjectionsPeriod" nillable="true" substitutionGroup="xbrli:item" type="us-types:durationStringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="wlk_DocumentAndEntityInformationAbstract" name="DocumentAndEntityInformationAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="wlk_EPSEthylenePipelineSdGmbHCo.KGMember" name="EPSEthylenePipelineSdGmbHCo.KGMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="wlk_ElectricityAndTechnicalServicesMember" name="ElectricityAndTechnicalServicesMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="wlk_EligibilityRequirementsLengthOfServiceRequiredForAnnualRetirementContribution" name="EligibilityRequirementsLengthOfServiceRequiredForAnnualRetirementContribution" nillable="true" substitutionGroup="xbrli:item" type="xbrli:durationItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="wlk_EmergencyEconomicStabilizationActOfTwoThousandEightMember" name="EmergencyEconomicStabilizationActOfTwoThousandEightMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="wlk_EnvironmentalCostsPercentageNetOfRecoveriesFromThirdParties" name="EnvironmentalCostsPercentageNetOfRecoveriesFromThirdParties" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="wlk_EthylenePipelineMember" name="EthylenePipelineMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="wlk_EthyleneStyreneAndOtherMember" name="EthyleneStyreneAndOtherMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="wlk_FairValueEstimatePolicyTextBlock" name="FairValueEstimatePolicyTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element id="wlk_FairValueOfConsiderationTransferred" name="FairValueOfConsiderationTransferred" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element id="wlk_FairValueOfInvestmentBeforeBusinessCombinationNetOfPreexistingBalances" name="FairValueOfInvestmentBeforeBusinessCombinationNetOfPreexistingBalances" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element id="wlk_FiniteLivedIntangibleAssetsAmortizationPeriodMaximum" name="FiniteLivedIntangibleAssetsAmortizationPeriodMaximum" nillable="true" substitutionGroup="xbrli:item" type="xbrli:durationItemType" xbrli:periodType="duration" />
  <xsd:element id="wlk_FiniteLivedIntangibleAssetsAmortizationPeriodMinimum" name="FiniteLivedIntangibleAssetsAmortizationPeriodMinimum" nillable="true" substitutionGroup="xbrli:item" type="xbrli:durationItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="wlk_FirmCommitmentDerivativeItemsDesignatedAsHedgesMember" name="FirmCommitmentDerivativeItemsDesignatedAsHedgesMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="wlk_FirstOneHalfIncrementOnAnniversaryOfAwardDateMember" name="FirstOneHalfIncrementOnAnniversaryOfAwardDateMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="wlk_FixedChargeCoverageRatio" name="FixedChargeCoverageRatio" nillable="true" substitutionGroup="xbrli:item" type="xbrli:decimalItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="wlk_GoZoneSixAndOneHalfPercentSeniorNotesDueTwentyTwentyNineMember" name="GoZoneSixAndOneHalfPercentSeniorNotesDueTwentyTwentyNineMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="wlk_GoZoneSixAndThreeQuartersPercentSeniorNotesDueTwentyThirtyTwoMember" name="GoZoneSixAndThreeQuartersPercentSeniorNotesDueTwentyThirtyTwoMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="wlk_GoZoneSixPointFivePercentTaxExemptRevenueBondsDueTwentyThirtyFiveMember" name="GoZoneSixPointFivePercentTaxExemptRevenueBondsDueTwentyThirtyFiveMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="wlk_GrossProceedsFromIssuanceOfCommonLimitedPartnersUnits" name="GrossProceedsFromIssuanceOfCommonLimitedPartnersUnits" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="wlk_GuarantorDisclosuresAbstract" name="GuarantorDisclosuresAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element id="wlk_GuarantorDisclosuresTextBlock" name="GuarantorDisclosuresTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="wlk_GulfOpportunityZoneActOfTwoThousandFiveMember" name="GulfOpportunityZoneActOfTwoThousandFiveMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="wlk_IkeZoneSixPointFivePercentTaxExemptRevenueBondsDueTwentyThirtyFiveMember" name="IkeZoneSixPointFivePercentTaxExemptRevenueBondsDueTwentyThirtyFiveMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="wlk_IncomeLossBeforeIncomeTaxes" name="IncomeLossBeforeIncomeTaxes" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element id="wlk_IncomeLossFromContinuingOperationsBeforeIncomeTaxes" name="IncomeLossFromContinuingOperationsBeforeIncomeTaxes" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element id="wlk_IncomeLossFromEquityMethodInvestmentsSubsidiaries" name="IncomeLossFromEquityMethodInvestmentsSubsidiaries" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element id="wlk_IncreaseDecreaseInPrepaidExpensesAndOtherCurrentAssets" name="IncreaseDecreaseInPrepaidExpensesAndOtherCurrentAssets" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="wlk_InfraServGendorfGmbHCo.KGMember" name="InfraServGendorfGmbHCo.KGMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="wlk_InfraServKnapsackGendorfGmbHCo.KGMember" name="InfraServKnapsackGendorfGmbHCo.KGMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="wlk_InfraServKnapsackGmbHCo.KGMember" name="InfraServKnapsackGmbHCo.KGMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="wlk_InsuranceRecoveryAbstract" name="InsuranceRecoveryAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element id="wlk_IntangibleAssetsAccumulatedAmortization" name="IntangibleAssetsAccumulatedAmortization" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="wlk_IntangibleAssetsGrossIncludingGoodwill" name="IntangibleAssetsGrossIncludingGoodwill" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element abstract="true" id="wlk_IntercompanyDebtMember" name="IntercompanyDebtMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="wlk_InternationalIndexFundsMember" name="InternationalIndexFundsMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="wlk_InventoryExchangePolicyTextBlock" name="InventoryExchangePolicyTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element id="wlk_InvestmentMaturityTerm" name="InvestmentMaturityTerm" nillable="true" substitutionGroup="xbrli:item" type="xbrli:durationItemType" xbrli:periodType="duration" />
  <xsd:element id="wlk_JointVenturesRetainedEarningsAccumulatedDeficit" name="JointVenturesRetainedEarningsAccumulatedDeficit" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element abstract="true" id="wlk_LargeCapIndexFundsMember" name="LargeCapIndexFundsMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="wlk_LetterOfCreditFacilitySublimit" name="LetterOfCreditFacilitySublimit" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="wlk_LineOfCreditFacilityLimitedToAccountsReceivablePercentage" name="LineOfCreditFacilityLimitedToAccountsReceivablePercentage" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="wlk_LineOfCreditFacilityLimitedToCashHeldInAccountWithAgentPercentage" name="LineOfCreditFacilityLimitedToCashHeldInAccountWithAgentPercentage" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="wlk_LineOfCreditFacilityLimitedToLesserOfEligibleInventoryOrderlyLiquidationValuePercentage" name="LineOfCreditFacilityLimitedToLesserOfEligibleInventoryOrderlyLiquidationValuePercentage" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="wlk_LineOfCreditFacilityLimitedToLesserOfEligibleInventoryPercentage" name="LineOfCreditFacilityLimitedToLesserOfEligibleInventoryPercentage" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="wlk_LineOfCreditFacilityPermittedIncrease" name="LineOfCreditFacilityPermittedIncrease" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element id="wlk_LineofCreditFacilityCovenantTermsAcquisitionsAndInvestmentsBorrowingAvailabilityThresholdPercentOfCommitmentsScenarioTwo" name="LineofCreditFacilityCovenantTermsAcquisitionsAndInvestmentsBorrowingAvailabilityThresholdPercentOfCommitmentsScenarioTwo" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="wlk_LineofCreditFacilityCovenantTermsAcquisitionsAndInvestmentsBorrowingAvailabilityThresholdScenarioTwo" name="LineofCreditFacilityCovenantTermsAcquisitionsAndInvestmentsBorrowingAvailabilityThresholdScenarioTwo" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="wlk_LineofCreditFacilityCovenantTermsAcquisitionsRestrictionsBorrowingAvailabilityThresholdPercentOfCommitmentsScenarioOne" name="LineofCreditFacilityCovenantTermsAcquisitionsRestrictionsBorrowingAvailabilityThresholdPercentOfCommitmentsScenarioOne" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="wlk_LineofCreditFacilityCovenantTermsAcquisitionsRestrictionsBorrowingAvailabilityThresholdPercentOfCommitmentsScenarioTwo" name="LineofCreditFacilityCovenantTermsAcquisitionsRestrictionsBorrowingAvailabilityThresholdPercentOfCommitmentsScenarioTwo" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="wlk_LineofCreditFacilityCovenantTermsAcquisitionsRestrictionsBorrowingAvailabilityThresholdScenarioOne" name="LineofCreditFacilityCovenantTermsAcquisitionsRestrictionsBorrowingAvailabilityThresholdScenarioOne" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="wlk_LineofCreditFacilityCovenantTermsDistributionsRestrictionsBorrowingAvailabilityThresholdPercentOfCommitmentsScenarioOne" name="LineofCreditFacilityCovenantTermsDistributionsRestrictionsBorrowingAvailabilityThresholdPercentOfCommitmentsScenarioOne" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="wlk_LineofCreditFacilityCovenantTermsDistributionsRestrictionsBorrowingAvailabilityThresholdScenarioOne" name="LineofCreditFacilityCovenantTermsDistributionsRestrictionsBorrowingAvailabilityThresholdScenarioOne" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="wlk_LineofCreditFacilityCovenantTermsSpecifiedAcquisitionsPermissible" name="LineofCreditFacilityCovenantTermsSpecifiedAcquisitionsPermissible" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="wlk_LineofCreditFacilityCovenantTermsSpecifiedAcquisitionsPermissiblePercentageOfTangibleAssets" name="LineofCreditFacilityCovenantTermsSpecifiedAcquisitionsPermissiblePercentageOfTangibleAssets" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="wlk_LineofCreditFacilityCovenantTermsSpecifiedDistributionsPermissible" name="LineofCreditFacilityCovenantTermsSpecifiedDistributionsPermissible" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element id="wlk_LineofCreditFacilityCovenantTermsSpecifiedDistributionsPermissibleAnnualIncreasePercentage" name="LineofCreditFacilityCovenantTermsSpecifiedDistributionsPermissibleAnnualIncreasePercentage" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="wlk_LineofCreditFacilityCovenantTermsSpecifiedInvestmentsPermissible" name="LineofCreditFacilityCovenantTermsSpecifiedInvestmentsPermissible" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="wlk_LineofCreditFacilityCovenantTermsSpecifiedInvestmentsPermissiblePercentageOfTangibleAssetsAndAcquisitions" name="LineofCreditFacilityCovenantTermsSpecifiedInvestmentsPermissiblePercentageOfTangibleAssetsAndAcquisitions" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="wlk_LossContingencyArbitrationIntervalPeriod" name="LossContingencyArbitrationIntervalPeriod" nillable="true" substitutionGroup="xbrli:item" type="xbrli:durationItemType" xbrli:periodType="duration" />
  <xsd:element id="wlk_MaximumDistributionPercentageOfSpecifiedNetCashProceeds" name="MaximumDistributionPercentageOfSpecifiedNetCashProceeds" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="wlk_MaximumEmployeeContributionAsPercentageOfAnnualCompensation" name="MaximumEmployeeContributionAsPercentageOfAnnualCompensation" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="wlk_MaximumNumberOfDaysFromChangeOfControlForBelowInvestmentGradeRatingEvent" name="MaximumNumberOfDaysFromChangeOfControlForBelowInvestmentGradeRatingEvent" nillable="true" substitutionGroup="xbrli:item" type="xbrli:durationItemType" xbrli:periodType="duration" />
  <xsd:element id="wlk_MaximumPercentageOfIncomeDistribution" name="MaximumPercentageOfIncomeDistribution" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="wlk_MaximumUnrestrictedDistributionsAllowableUnderDebtCovenants" name="MaximumUnrestrictedDistributionsAllowableUnderDebtCovenants" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element id="wlk_MaximumUnrestrictedQuarterlyDividendsAllowableUnderDebtCovenants" name="MaximumUnrestrictedQuarterlyDividendsAllowableUnderDebtCovenants" nillable="true" substitutionGroup="xbrli:item" type="xbrli:decimalItemType" xbrli:periodType="duration" />
  <xsd:element id="wlk_MinimumDebtAmountGuaranteedBySubsidiaries" name="MinimumDebtAmountGuaranteedBySubsidiaries" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="wlk_NetIncomeLossAvailableToCommonStockholders" name="NetIncomeLossAvailableToCommonStockholders" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element id="wlk_NetIncomeLossAvailableToParticipatingSecurities" name="NetIncomeLossAvailableToParticipatingSecurities" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element id="wlk_NetProceedsDistributedToParentCompanyFromInitialPublicOffering" name="NetProceedsDistributedToParentCompanyFromInitialPublicOffering" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element id="wlk_NoncontrollingInterestAcquired" name="NoncontrollingInterestAcquired" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element id="wlk_NoncurrentAssetsOtherGross" name="NoncurrentAssetsOtherGross" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="wlk_NoncurrentAssetsOtherNet" name="NoncurrentAssetsOtherNet" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="wlk_NumberOfMultiemployerPlans" name="NumberOfMultiemployerPlans" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="duration" />
  <xsd:element id="wlk_NumberOfPlants" name="NumberOfPlants" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="instant" />
  <xsd:element id="wlk_NumberOfProductionFacilities" name="NumberOfProductionFacilities" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="instant" />
  <xsd:element id="wlk_NumberOfSegments" name="NumberOfSegments" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="duration" />
  <xsd:element id="wlk_NumberOfSubsidiariesCompanyProvidesPostRetirementHealthcareBenefit" name="NumberOfSubsidiariesCompanyProvidesPostRetirementHealthcareBenefit" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="duration" />
  <xsd:element id="wlk_NumberofCreditRatingAgencies" name="NumberofCreditRatingAgencies" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="duration" />
  <xsd:element id="wlk_OfficeLeaseExpense" name="OfficeLeaseExpense" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="wlk_OlefinsMember" name="OlefinsMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="wlk_OrdinaryDividendMember" name="OrdinaryDividendMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="wlk_OrganizationConsolidationAndPresentationOfFinancialStatementsLineItems" name="OrganizationConsolidationAndPresentationOfFinancialStatementsLineItems" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="wlk_OrganizationConsolidationAndPresentationOfFinancialStatementsTable" name="OrganizationConsolidationAndPresentationOfFinancialStatementsTable" nillable="true" substitutionGroup="xbrldt:hypercubeItem" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="wlk_OtherAmortizableAssetsMember" name="OtherAmortizableAssetsMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="wlk_OtherAssetsLineItems" name="OtherAssetsLineItems" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element id="wlk_OtherAssetsNoncurrentAccumulatedAmortization" name="OtherAssetsNoncurrentAccumulatedAmortization" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element abstract="true" id="wlk_OtherAssetsNoncurrentAxis" name="OtherAssetsNoncurrentAxis" nillable="true" substitutionGroup="xbrldt:dimensionItem" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="wlk_OtherAssetsNoncurrentByTypeDomain" name="OtherAssetsNoncurrentByTypeDomain" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="wlk_OtherAssetsNoncurrentGross" name="OtherAssetsNoncurrentGross" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="wlk_OtherComprehensiveIncomeLossIncomeTaxProvisionBenefitOnAvailableForSaleInvestment" name="OtherComprehensiveIncomeLossIncomeTaxProvisionBenefitOnAvailableForSaleInvestment" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="wlk_OtherForeignCountriesMember" name="OtherForeignCountriesMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="wlk_OtherOwnershipInterestsPercentageofOwnershipAfterTransaction" name="OtherOwnershipInterestsPercentageofOwnershipAfterTransaction" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="wlk_OtherPolicyTextBlock" name="OtherPolicyTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="wlk_PVCFilmMember" name="PVCFilmMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="wlk_PVCResinMember" name="PVCResinMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="wlk_PaymentsForConstructionOfAssetsPendingSaleLeaseback" name="PaymentsForConstructionOfAssetsPendingSaleLeaseback" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element id="wlk_PaymentsofUnitIssuanceCosts" name="PaymentsofUnitIssuanceCosts" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element id="wlk_PensionandOtherPostretirementBenefitPlansAccumulatedOtherComprehensiveIncomeLossForeignCurrencyTranslationAdjustmentBeforeTax" name="PensionandOtherPostretirementBenefitPlansAccumulatedOtherComprehensiveIncomeLossForeignCurrencyTranslationAdjustmentBeforeTax" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="wlk_PercentageOfEmployeeContributionFullyMatchedByCompany" name="PercentageOfEmployeeContributionFullyMatchedByCompany" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="wlk_PercentageOfPrincipalRequiredIfCalled" name="PercentageOfPrincipalRequiredIfCalled" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="wlk_PipelineFeesForTransportOfEthyleneFeedstocksMember" name="PipelineFeesForTransportOfEthyleneFeedstocksMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="wlk_PipelineFeesForTransportOfNaturalGasLiquidFeedstocksMember" name="PipelineFeesForTransportOfNaturalGasLiquidFeedstocksMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="wlk_PipelineUsageFees" name="PipelineUsageFees" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="wlk_PlantAndEquipmentMember" name="PlantAndEquipmentMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="wlk_PlantAndEquipmentPlannedMajorMaintenanceActivitiesAmortizationPeriodMaximum" name="PlantAndEquipmentPlannedMajorMaintenanceActivitiesAmortizationPeriodMaximum" nillable="true" substitutionGroup="xbrli:item" type="xbrli:durationItemType" xbrli:periodType="duration" />
  <xsd:element id="wlk_PlantAndEquipmentPlannedMajorMaintenanceActivitiesAmortizationPeriodMinimum" name="PlantAndEquipmentPlannedMajorMaintenanceActivitiesAmortizationPeriodMinimum" nillable="true" substitutionGroup="xbrli:item" type="xbrli:durationItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="wlk_PolyOneCorporationMember" name="PolyOneCorporationMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="wlk_PolyethyleneMember" name="PolyethyleneMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="wlk_PreformationCapitalExpenditureMember" name="PreformationCapitalExpenditureMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="wlk_ProceedsFromRepaymentsOfIntercompanyFinancing" name="ProceedsFromRepaymentsOfIntercompanyFinancing" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element id="wlk_ProceedsFromRepaymentsofAcquiredLoan" name="ProceedsFromRepaymentsofAcquiredLoan" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element id="wlk_ProceedsfromRepaymentsofIntercompanyFinancingSubsidiary" name="ProceedsfromRepaymentsofIntercompanyFinancingSubsidiary" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element id="wlk_PropertyPlantAndEquipmentGrossExcludingConstructionInProgress" name="PropertyPlantAndEquipmentGrossExcludingConstructionInProgress" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="wlk_PropertyPlantAndEquipmentNetExcludingConstructionInProgress" name="PropertyPlantAndEquipmentNetExcludingConstructionInProgress" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="wlk_PurchasesAndLeaseExpense" name="PurchasesAndLeaseExpense" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="wlk_PvcCausticSodaAndOtherMember" name="PvcCausticSodaAndOtherMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="wlk_RangeFiveMember" name="RangeFiveMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="wlk_RangeFourMember" name="RangeFourMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="wlk_RangeOneMember" name="RangeOneMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="wlk_RangeThreeMember" name="RangeThreeMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="wlk_RangeTwoMember" name="RangeTwoMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="wlk_RatablyOnAnnualBasisMember" name="RatablyOnAnnualBasisMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="wlk_ReconciliationOfProceedsFromInitialPublicOfferingTableTextBlock" name="ReconciliationOfProceedsFromInitialPublicOfferingTableTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="wlk_SalariedPensionPlanMember" name="SalariedPensionPlanMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="wlk_SaleofUnitPricePerUnit" name="SaleofUnitPricePerUnit" nillable="true" substitutionGroup="xbrli:item" type="num:perShareItemType" xbrli:periodType="instant" />
  <xsd:element id="wlk_ScheduleOfAccountsAndFinancingReceivablesTextBlock" name="ScheduleOfAccountsAndFinancingReceivablesTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element id="wlk_ScheduleOfEstimatedUsefulLivesOfAssetsTableTextBlock" name="ScheduleOfEstimatedUsefulLivesOfAssetsTableTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element id="wlk_ScheduleOfNetBenefitCostsAndAmountsRecognizedInOtherComprehensiveIncomeLossTableTextBlock" name="ScheduleOfNetBenefitCostsAndAmountsRecognizedInOtherComprehensiveIncomeLossTableTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element id="wlk_ScheduleOfNetIncomeLossAttributableToCommonStockholdersTableTextBlock" name="ScheduleOfNetIncomeLossAttributableToCommonStockholdersTableTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="wlk_ScheduleOfOtherAssetsTable" name="ScheduleOfOtherAssetsTable" nillable="true" substitutionGroup="xbrldt:hypercubeItem" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element id="wlk_ScheduleOfOtherNonoperatingIncomeExpenseByComponentTextBlock" name="ScheduleOfOtherNonoperatingIncomeExpenseByComponentTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="wlk_SecondOneHalfIncrementOnAnniversaryOfAwardDateMember" name="SecondOneHalfIncrementOnAnniversaryOfAwardDateMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="wlk_SmallCapIndexFundsMember" name="SmallCapIndexFundsMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="wlk_StockRepurchaseProgramSharesRepurchasedGross" name="StockRepurchaseProgramSharesRepurchasedGross" nillable="true" substitutionGroup="xbrli:item" type="xbrli:sharesItemType" xbrli:periodType="instant" />
  <xsd:element abstract="true" id="wlk_SubjecttoMasterNettingMember" name="SubjecttoMasterNettingMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="wlk_SubsidiaryInitialPublicOfferingUseOfProceeds" name="SubsidiaryInitialPublicOfferingUseOfProceeds" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element abstract="true" id="wlk_SuzhouHuasuPlasticsCompanyLtdMember" name="SuzhouHuasuPlasticsCompanyLtdMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="wlk_ThreePointSixZeroPercentageSeniorNotesDueTwentyTwentyTwoMember" name="ThreePointSixZeroPercentageSeniorNotesDueTwentyTwentyTwoMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="wlk_TotalDeferredChargesandOtherAssetsNonCurrentNet" name="TotalDeferredChargesandOtherAssetsNonCurrentNet" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="wlk_TotalDeferredChargesandOtherAssetsNoncurrentGross" name="TotalDeferredChargesandOtherAssetsNoncurrentGross" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="wlk_TradeCustomerAndAffiliateReceivableNetCurrent" name="TradeCustomerAndAffiliateReceivableNetCurrent" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="wlk_TreasuryStockValueCostMethod" name="TreasuryStockValueCostMethod" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="wlk_TurnaroundCostsGross" name="TurnaroundCostsGross" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="wlk_TurnaroundCostsNet" name="TurnaroundCostsNet" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element abstract="true" id="wlk_TypeOfAgreementAxis" name="TypeOfAgreementAxis" nillable="true" substitutionGroup="xbrldt:dimensionItem" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="wlk_TypeOfAgreementDomain" name="TypeOfAgreementDomain" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="wlk_UnrealizedHoldingLossesOnInvestmentsNetOfTaxMember" name="UnrealizedHoldingLossesOnInvestmentsNetOfTaxMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="wlk_VinnolitMember" name="VinnolitMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="wlk_VinylChlorideMonomerMember" name="VinylChlorideMonomerMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="wlk_VinylsMember" name="VinylsMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="wlk_WagePensionPlanMember" name="WagePensionPlanMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="wlk_WasteDisposalRevenueBondsDueTwentyTwentySevenMember" name="WasteDisposalRevenueBondsDueTwentyTwentySevenMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="wlk_WestlakeChemicalOpCoLPMember" name="WestlakeChemicalOpCoLPMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="wlk_WestlakeChemicalPartnersLPMember" name="WestlakeChemicalPartnersLPMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
</xsd:schema>
