EXHIBIT 2.2

                       ASSIGNMENT AND ASSUMPTION AGREEMENT

             This Assignment and Assumption Agreement is executed and
        delivered this 6th day of October, 1997, but to be effective as
        of the 1st day of September, 1997, by and among Remediation
        Technologies, Inc., a Delaware corporation ("RETEC"), RETEC
        THERMAL, INC., a Delaware corporation ("Seller"), TETRA
        Technologies, Inc., a Delaware corporation ("TETRA") and TETRA
        THERMAL, INC., a Delaware corporation ("Buyer").

                                    RECITALS

             1.   The parties have entered into a Purchase and Sale
        Agreement of even date herewith (hereinafter referred to as the
        "Purchase Agreement") which provides for the transfer and sale of
        Seller's Limited Liability Company Interest in the LLC and in all
        Projects for consideration in the amount and on the terms and
        conditions provided in the Purchase Agreement.

             2.   In partial consideration for Seller's Limited Liability
        Company Interest and in all Projects, Section 2.3 of the Purchase
        Agreement requires that Buyer assume and agree to pay, perform
        and discharge all debts, obligations and liabilities (other than
        liabilities for which RETEC and Seller are obligated to indemnify
        Buyer and TETRA) of the LLC or its successors, and defend RETEC
        and Seller against claims to pay the same, as provided herein, or
        upon demand of Seller or RETEC cause the LLC itself or its
        successors to pay, perform, discharge and defend RETEC and Seller
        against claims to pay any such debts, obligations and liabilities
        (other than liabilities for which RETEC and Seller are obligated
        to indemnify Buyer and TETRA).

             NOW, THEREFORE, in consideration of the foregoing premises
        and for other good and valuable consideration, the receipt and
        sufficiency of which are hereby acknowledged, the parties hereby
        agree as follows:

             1.   Definitions.  All capitalized terms used herein which
        are not otherwise defined shall have the same meaning as in the
        Purchase Agreement.

             2.    Seller's Assignment and Transfer.  Seller hereby
        assigns, transfers and conveys all of its Limited Liability
        Company Interest in the LLC and in the Projects to Buyer and
        shall deliver to Buyer a certificate to this effect in the form
        attached hereto as Exhibit A.
         
             3.   Assumption of Liabilities.  Buyer hereby assumes and
        agrees to pay, perform and discharge when due all obligations,
        debts and liabilities (other than liabilities for which RETEC and
        Seller are obligated to indemnify Buyer and TETRA) of the LLC or
        its successors (the "LLC Liabilities"), or upon demand of Seller
        or RETEC cause the LLC or its successors to do so, whether
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        arising or incurred before or after the date hereof, including
        but not limited to the following: (i) liabilities arising out of
        the release of any materials of environmental concern resulting
        from or relating to the operation of the business of the LLC or
        any predecessor business or company of the LLC (including without
        limitation the transportation of materials of environmental
        concern or the storage, treatment, reclamation, recycling or
        disposal thereof); (ii) any violation of any environmental law or
        regulation by the LLC or any predecessor business or company of
        the LLC; (iii) any liability for taxes relating to operations of
        the LLC; (iv) all contracts and commitments for the sale, lease
        or servicing of products or services of the LLC and for the
        purchase or lease of materials, equipment, supplies, or services;
        (v) all payables for materials, equipment or services owed by the
        LLC; (vi) all warranty and indemnity obligations in respect of
        the operations, products, services and business of the LLC; (vii)
        the defense of all litigation and claims made arising out of the
        operation, services, products and business of the LLC, including
        all claims that the products or services of the LLC infringe the
        patent, copyright, trade secret, trademark, tradename or other
        intellectual property rights of third parties, and the payment of
        any judgments resulting from such claims, or settlement of such
        claims; (viii) all bank and other loans made to the LLC, whether
        or not guaranteed to any party hereto.  Buyer further agrees to
        defend RETEC and Seller, or upon demand of RETEC or Seller cause
        the LLC to defend RETEC and Seller, against any claim, demand or
        cause of action made by a third party demanding that RETEC or
        Seller pay or is obligated to pay an LLC Liability.
        Notwithstanding anything contained in this Agreement to the
        contrary, Buyer does not indemnify or assume any liability of
        Seller for taxes imposed on the Seller related to the LLC's
        assets, business or operation for taxable periods or portions
        thereof ending on or before the date hereof.

             4.   Other Documents.  Buyer and TETRA for themselves and
        their successors and assigns, further agree, at Seller's or
        RETEC's reasonable request and without further consideration, to
        prepare, execute, acknowledge, and deliver to either of them or
        their designees such other instruments of assumption and
        acknowledgment, or take such further action as either of them may
        reasonably request, to effectuate Buyer's assumption of the LLC
        Liabilities and defense of any claim against RETEC or Seller to
        pay any LLC Liability.

             5.   Successors and Assigns.  This Agreement shall inure to
        the benefit of and be binding upon the successors and assigns of
        each of the parties hereto.

             IN WITNESS WHEREOF, a duly authorized officer of each of the
        parties hereto has executed and delivered this Agreement as of
        the date and year first above written.

                                        2PAGE

        Remediation Technologies, Inc.     TETRA Technologies, Inc.
        By /s/ Robert W. Dunlap            By /s/ Geoffrey M. Hertel 
        Its President                      Its Executive Vice President 


        RETEC THERMAL, INC.                TETRA THERMAL, INC.

        By /s/ Robert W. Dunlap            By /s/ Geoffrey M. Hertel 
        Its President                      Its Vice President