Exhibit 2.8
            AMENDMENT NO. 1 TO STOCK PURCHASE AGREEMENT



      WHEREAS, THERMO TERRATECH INC., a Delaware corporation (the "Seller"), and
THE RANDERS GROUP  INCORPORATED,  a Delaware  corporation  (the  "Buyer"),  have
entered  into  that  certain  Stock  Purchase  Agreement  (the  "Agreement")  on
September  19, 1997  providing  for the sale of the capital  stock of The Killam
Group Inc. ("Killam") by the Seller to the Buyer;

      WHEREAS,  the Agreement  contemplated  that in consideration of such sale,
the Buyer would issue to the Seller  103,569,600  fully paid and  non-assessable
shares of the Buyer's  common  stock,  subject to a  post-closing  adjustment as
described in Section 2.2 of the Agreement;

      WHEREAS, as of April 4, 1998 (the end of the Buyer's and the Seller's most
recently completed fiscal year), the post-closing adjustment mechanism set forth
in  Section  2.2 of the  Agreement  would  have  resulted  in  the  issuance  of
113,031,051 shares of the Buyer's common stock to the Seller in consideration of
the sale of Killam to the Buyer;

      WHEREAS,  the Buyer and the Seller wish to stabilize  the number of shares
of the Buyer's common stock to be issued in  consideration of the sale of Killam
to the Buyer as of April 4, 1998;

      WHEREAS,  the Buyer's Board of Directors has  recommended,  subject to the
approval of the Buyer's  shareholders,  that Buyer effect a one-for-five reverse
split of its common stock (the "Reverse Stock Split"); and

      WHEREAS, the Buyer and the Seller wish to give effect to the Reverse Stock
Split prior to the  issuance of the shares of Buyer's  common stock to Seller as
contemplated by the 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 1 of the Agreement is hereby amended by deleting the definition
of "Base Purchase Price" and by adding the following  definition in alphabetical
order within such Section:

      "'Purchase Price' has the meaning set forth in ss.2.2 below."

      2. Section 1 of the  Agreement is hereby  further  amended by deleting the
definition of "Closing Balance Sheet."

      3.  Section 1 of the  Agreement  is hereby  further  amended by adding the
following definition in alphabetical order within such Section:

      "'Reverse Stock Split' has the meaning set forth in ss.7.2(i)
      below."

      4.  Section 2.2 of the  Agreement  is hereby  amended and  restated in its
entirety as follows:

      "2.2 Purchase Consideration.  The Buyer shall deliver to the Seller at the
      Closing  22,606,210  fully paid and  non-assessable  shares  (after giving
      effect to the Reverse  Stock Split) of RGI Stock (the  "Purchase  Price").
      The parties  acknowledge  and agree that the number of shares of RGI Stock
      to be delivered at the Closing in payment of the Purchase Price represents
      the  audited  book value of Killam  Group as of April 4, 1998,  divided by
      $3.125 (or $0.625  multiplied by 5, to take into account the Reverse Stock
      Split) per share of RGI Stock so issued."

      5. Section 7.2 of the  Agreement is amended by inserting the following new
clause (i) therein and by renumbering all subsequent clauses accordingly:

                "(i) the Seller shall have effected a reverse stock split of one
      share of RGI Stock for every  five  shares  outstanding  of such RGI Stock
      (the "Reverse  Stock  Split") in accordance  with the laws of the State of
      Delaware;"

      6.  Section 8.4 of the  Agreement  is hereby  amended and  restated in its
entirety as follows:

      "8.4 Indemnification Ceiling Amount.  In no event will the
      total amount payable by either Seller or Buyer pursuant to
      ss.8.2 or ss.8.3 exceed an amount equal to the Purchase Price
      for the Killam Shares."

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

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

      IN WITNESS WHEREOF,  the Parties hereto have executed this Agreement as of
the 4th day of April, 1998.


THE RANDERS GROUP INCORPORATED THERMO TERRATECH INC.


By:   /s/ Thomas R. Eurich                By:  /s/ John P. Appleton
      Thomas R. Eurich                         John P. Appleton
      Vice President                           President and CEO