Exhibit 4.11


                                 January 1, 1998


CLEAN HARBORS ENVIRONMENTAL
    SERVICES, INC.
CLEAN HARBORS TECHNOLOGY
    CORPORATION
CLEAN HARBORS KINGSTON FACILITY
    CORPORATION
CLEAN HARBORS OF BRAINTREE, INC.
CLEAN HARBORS SERVICES, INC.
CLEAN HARBORS OF NATICK, INC.
CLEAN HARBORS OF CONNECTICUT, INC.
MURPHY'S WASTE OIL SERVICE, INC.
CLEAN HARBORS OF CLEVELAND, INC.
MR. FRANK, INC.
SPRING GROVE RESOURCE RECOVERY, INC.

    Re:  Fifth Amendment to Financing Agreements ("Fifth Amendment")

Gentlemen:

    Reference is made to the Loan and Security Agreement dated May 8, 1995, 
as amended, between you and the undersigned (the "Loan Agreement"). All 
capitalized terms not otherwise defined herein shall have the meanings given 
such terms in the Loan Agreement.

    Borrowers have requested amendments to certain of the covenants set forth 
in the Loan Agreement. Subject to the terms and conditions hereof, the Lender 
agrees with the Borrowers as follows:

    (1) Section 9.13 of the Loan Agreement is deleted in its entirety and 
replaced with the following:

        "Parent shall, at all times, maintain Working Capital of not 
        less than $6,000,000.00."

    (2) Section 9.14 of the Loan Agreement is deleted in its entirety and 
replaced with the following:

        "Parent shall, at all times, maintain Adjusted Net Worth of 
        not less than $33,000,000.00."

    (3) This Fifth Amendment and the Lender's obligations hereunder shall not be

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effective until each of the following conditions are satisfied:


          (a) all requisite corporate action and proceedings of the Borrowers 
in connection with this Fifth Amendment shall be satisfactory in form and 
substance to Lender and Lender shall receive certified copies of such 
corporate action and proceedings as Lender may request;

          (b) no material adverse change shall have  occurred in the assets, 
business or prospects of any Borrower since the date of the most recent 
financial statements furnished to Lender pursuant to the Loan Agreement and 
no change or event shall have occurred which would impair the ability of any 
Borrower or any Obligor to perform its obligations under the Loan Agreement 
or any of the other Financing Agreements or of Lender to enforce the 
Obligations or to realize upon the Collateral.

    (4) Each Borrower confirms and agrees that (a) all representations and 
warranties contained in the Loan Agreement and in the other Financing 
Agreements are on the date hereof true and correct in all material respects 
(except for changes that have occurred as permitted by the covenants in 
Section 9 of the Loan Agreement), and (b) it is unconditionally and jointly 
and severally liable for the punctual and full payment of all Obligations, 
including, without limitation, all charges, fees, expenses and costs 
(including attorneys' fees and expenses) under the Financing Agreements, and 
that no Borrower has any defenses, counterclaims or setoffs with respect to 
full, complete and timely payment of all Obligations.

    (5) Each Guarantor, for value received, hereby assents to the Borrowers' 
execution and delivery of this Fifth Amendment, and to the performance by the 
Borrowers of their respective agreements and obligations hereunder. This 
Amendment and the performance or consummation of any transaction or matter 
contemplated under this Amendment, shall not limit, restrict, extinguish or 
otherwise impair any of the Guarantor's liability to Lender with respect to 
the payment and other performance obligations of the Guarantors pursuant to 
the Guarantees, dated May 8, 1995 executed for the benefit of Lender. Each 
Guarantor acknowledges that it is unconditionally liable to Lender for the 
full and complete payment of all Obligations including, without limitation, 
all charges, fees, expenses and costs (including attorney's fees and 
expenses) under the Financing Agreements and that such Guarantor has no 
defenses, counterclaims or setoffs with respect to full, complete and timely 
payment of any and all Obligations.

    (6) Borrowers hereby agree to pay to Lender all reasonable attorney's 
fees and costs which have been incurred or may in the future be incurred by 
Lender in connection with the negotiation and preparation of this Fifth 
Amendment and any other documents and agreements prepared in connection with 
this Fifth Amendment. The undersigned confirm that the Financing Agreements 
remain in full force and effect without amendment or modification of any 
kind, except for the amendments explicitly set forth herein. The undersigned 
further confirm that no Event of Default or events which with notice or the 
passage of time or both would constitute an Event of Default have occurred 

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and are continuing. The execution and delivery of this Fifth Amendment by Lender
shall not be construed as a waiver by Lender of any Event of Default under the
Financing Agreements. This Fifth Amendment shall be deemed to be a Financing
Agreement and, together with the other Financing Agreements, constitute the
entire agreement between the parties with respect to the subject matter hereof
and supersedes all prior dealings, correspondence, conversations or
communications between the parties with respect to the subject matter hereof.

    If you accept and agree to the foregoing please sign and return the 
enclosed copy of this letter. Thank you.

                                Very truly yours,

                                CONGRESS FINANCIAL CORPORATION
                                (NEW ENGLAND)


                                  By:   /s/ KATHLEEN J. MERRITT
                                     ------------------------------------
                                     Name:  Kathleen J. Merritt
                                          -------------------------------
                                     Title: Assistant Vice President
                                           ------------------------------
 
AGREED:

CLEAN HARBORS ENVIRONMENTAL
    SERVICES, INC.
CLEAN HARBORS TECHNOLOGY
    CORPORATION
CLEAN HARBORS KINGSTON FACILITY
    CORPORATION
CLEAN HARBORS OF BRAINTREE, INC.
CLEAN HARBORS SERVICES, INC.
CLEAN HARBORS OF NATICK, INC.
CLEAN HARBORS OF CONNECTICUT, INC.
MURPHY'S WASTE OIL SERVICE, INC.
CLEAN HARBORS OF CLEVELAND, INC.
MR. FRANK, INC.
SPRING GROVE RESOURCE RECOVERY, INC.


By:   /s/ STEVEN MOYNIHAN
   ----------------------------------------
   Name:  Steven Moynihan
   Title: Senior Vice President


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GUARANTORS:

CLEAN HARBORS, INC.

By:   /s/ STEVEN MOYNIHAN
   ----------------------------------------
   Name:  Steven Moynihan
   Title: Senior Vice President


CLEAN HARBORS OF BALTIMORE, INC.


By:  /s/  STEVEN MOYNIHAN
   ----------------------------------------
   Name:  Steven Moynihan
   Title: Senior Vice President

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