Exhibit 2.5
                               AMENDMENT NO. 1 TO
                 STOCK PURCHASE AND SALE AGREEMENT


      WHEREAS, Thermo TerraTech Inc., a Delaware corporation ("TTT"), and Thomas
R. Eurich, Michael J. Krivitzky, Thomas J. McEnhill and Bruce M. Bourdon (each
such person, individually, a "Seller" and all such persons collectively, the
"Sellers"), are parties to that certain Stock Purchase and Sale Agreement made
and entered into on May 12, 1997, pursuant to which TTT acquired a majority of
the issued and outstanding shares of the capital stock of The Randers Group
Incorporated ("RGI") from the Sellers (the "Agreement");

      WHEREAS, pursuant to a Stock Purchase Agreement of even date herewith (the
"Killam Agreement"), TTT has agreed to transfer to RGI all of the issued and
outstanding capital stock of The Killam Group Inc. ("Killam") in consideration
of the issuance by RGI of additional shares of its common stock to TTT;

      WHEREAS, in connection with execution and delivery of the Killam
Agreement, RGI, TTT, the Sellers and one other party have entered into a certain
agreement of even date herewith, providing for certain Severance Payments (as
such term is defined therein) to the Sellers and such other party under certain
circumstances; and

      WHEREAS, the parties wish to amend certain provisions of the Agreement to
better reflect their intentions in consideration of the execution and delivery
of the Killam Agreement and the Related Agreement;

      NOW, THEREFORE, in consideration of the premises and the mutual covenants,
agreements and provisions herein contained, the parties hereto, intending to be
legally bound, agree as follows:

      1. Section 5.4(a) of the Agreement is hereby amended and restated in its
entirety as follows:

           "(a) Each Seller agrees that, while he is employed by the Company,
      and for a period of two years after (i) the termination of the Seller's
      employment by the Company with Cause (as defined in the first sentence of
      Section 5.4(d) below), or (ii) the termination of the Seller's employment
      without Cause (as defined in the second sentence of Section 5.4(d) below),
      the Seller will not, directly or indirectly:

                (i) engage in any business that provides any services or
      products competitive with those offered by the Company as of the date of
      such resignation or termination in any jurisdiction within the United
      States of America in which the Company then offer such services or
      products, or

                (ii) without the prior written consent of the Company, (i)
      solicit any person employed by the Company (or any of its affiliates) to
      terminate his employment with the Company (or any of such affiliates) or
      to become an employee of the Seller or any person or entity with which the
      Seller may be affiliated, or (ii) hire any such employee except employees
      involuntarily terminated by the Company (or any of its affiliates)."

      2. Section 5.4(d) of the Agreement is hereby amended and restated in its
entirety as follows:

           "(d) For purposes of this Agreement only, "Cause" for termination of
      the Seller's employment by the Company shall be deemed to exist upon (i) a
      good faith finding by the Company of the failure of the Seller to perform
      his assigned duties for the Company, a material violation of any policy
      established by the Company (or its affiliates) and made known to the
      Seller, gross insubordination, dishonesty, gross negligence or gross
      misconduct, or (ii) the conviction of the Seller of, or the entry of a
      pleading of guilty or nolo contendere by the Seller to, any crime
      involving moral turpitude or any felony. "Cause" for termination of the
      Seller's employment by the Seller shall be deemed to exist upon (i) the
      Company's assignment to the Seller of duties fundamentally incompatible
      with the duties of the Seller as of the date of this Agreement (although
      the Seller's actual title or officer and/or director status may be changed
      or eliminated and that alone will not be considered "Cause") or (ii) a
      reduction in the Seller's current base salary prior to September 1, 1998."

      3. Section 5.4 of the Agreement is hereby further amended by adding the
following subsection (h) immediately after subsection (g) thereof:

           "(h) Notwithstanding any provision of this Section 5.4 to the
      contrary, in no event shall any Seller engage in any of the activities
      prohibited by clauses (i) or (ii) of Subsection 5.4(a) hereof during any
      period in, or with respect to, which such Seller is receiving or has
      received a Severance Payment (as such term is defined in that certain
      agreement of even date herewith providing, among other things, for such
      Severance Payments under certain circumstances to the Sellers and to one
      other party)."

      4. Except as set forth herein, the Agreement shall remain in full force
and effect in accordance with its terms.

      5. This Amendment may be executed in two or more counterparts, each of
which shall be deemed an original but all of which together shall constitute one
and the same instrument.


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      IN WITNESS WHEREOF, the Parties hereto have executed this Agreement as of
the 19th day of September, 1997.


THERMO TERRATECH INC.


By: /s/ John P. Appleton
      John P. Appleton
      President and CEO



/s/ Thomas R. Eurich
/s/ Michael J. Krivitzky
     Thomas R. Eurich
Michael J. Krivitzky


/s/ Thomas J. McEnhill
/s/ Bruce M. Bourdon
     Thomas J. McEnhill
Bruce M. Bourdon