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SEC EDGAR · Amended filing

CLH: amended insider filing

An amended ownership report was filed. Read the original and amendment before comparing transactions.

Follow CLH
Became public
Aug 14, 2026, 9:17 AM EDT
Event / period date
Mar 13, 2026
Collected
Nov 9, 2026, 9:26 AM 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

GERSTENBERG ERIC W (CO-CEO)

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/A</documentType>

    <periodOfReport>2026-03-13</periodOfReport>

    <dateOfOriginalSubmission>2026-03-17</dateOfOriginalSubmission>

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

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001211558</rptOwnerCik>
            <rptOwnerName>GERSTENBERG ERIC W</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerNonUSAddressFlag>false</rptOwnerNonUSAddressFlag>
            <rptOwnerStreet1>C/O CLEAN HARBORS ENVIRON. SERVICES INC.</rptOwnerStreet1>
            <rptOwnerStreet2>42 LONGWATER DRIVE</rptOwnerStreet2>
            <rptOwnerCity>NORWELL</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>02061</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>false</isDirector>
            <isOfficer>true</isOfficer>
            <isTenPercentOwner>false</isTenPercentOwner>
            <isOther>false</isOther>
            <officerTitle>CO-CEO</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <aff10b5One>0</aff10b5One>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2026-03-13</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>F</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>977</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>288.93</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>63023</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2026-03-13</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>D</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>2166</value>
                    <footnoteId id="F3"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>60857</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">Payment of tax liability by withholding of securities incident to vesting of securities in accordance with Rule 16b.</footnote>
        <footnote id="F2">Correction to Total Number of Shares Held.</footnote>
        <footnote id="F3">Shares of restricted stock forfeited due to the Company not achieving performance targets under its Long Term Equity Incentive Program.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Eric W. Gerstenberg</signatureName>
        <signatureDate>2026-08-14</signatureDate>
    </ownerSignature>
</ownershipDocument>

Price change after we could observe it

-0.01% CLH

Adjusted closing prices from Nov 10, 2026 to Nov 11, 2026. SPY changed 1.32% over the same dates. The start is the first available close after both publication and collection. This is a price comparison, not an executed trade, investor profit, or a backtested strategy.

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.