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SEC EDGAR · Insider purchase

CLH: Polito Karyn reported buying shares

1 reported purchase of non-derivative securities. Code P includes open-market and private purchases; it does not establish motive.

Follow CLH
Became public
Nov 2, 2026, 8:04 AM EST
Event / period date
Oct 29, 2026
Collected
Nov 7, 2026, 5:57 PM EST

Why this is connected

This filing identifies CLEAN HARBORS INC as the issuer of the security. The company's SEC identifier connects it to CLH.

Open the original source ↗Follow company activity in CLH

Reported transactions

Polito Karyn (Director)

125 shares · Common Stock

Oct 29, 2026 · $314.83 per share

Value calculated from the reported shares and prices: $39,353.75.

Code P covers open-market and private purchases. Grants, option exercises, and tax withholding are excluded from purchase results. Read the source footnotes for ownership and pricing details.

Source evidence

Read the source excerpt or record
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0609</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2026-10-29</periodOfReport>

    <issuer>
        <issuerCik>0000822818</issuerCik>
        <issuerName>CLEAN HARBORS INC</issuerName>
        <issuerTradingSymbol>CLH</issuerTradingSymbol>
        <issuerForeignTradingSymbol></issuerForeignTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001965457</rptOwnerCik>
            <rptOwnerName>Polito Karyn</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerNonUSAddressFlag>false</rptOwnerNonUSAddressFlag>
            <rptOwnerStreet1>C/O CLEAN HARBORS, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>42 LONGWATER DRIVE</rptOwnerStreet2>
            <rptOwnerCity>NORWELL</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>02061</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>true</isDirector>
            <isOfficer>false</isOfficer>
            <isTenPercentOwner>false</isTenPercentOwner>
            <isOther>false</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <aff10b5One>0</aff10b5One>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2026-10-29</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>125</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>314.83</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>4252</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes></footnotes>

    <ownerSignature>
        <signatureName>/s/ Karyn Polito</signatureName>
        <signatureDate>2026-11-02</signatureDate>
    </ownerSignature>
</ownershipDocument>

Congressional trading in CLH

These disclosures provide context. Their presence does not establish a link between a trader and the event.

Original documents control. Public records can be amended, and company connections may require interpretation. Nothing here is investment advice.