SECURITIES AND EXCHANGE COMMISSION

                             Washington, D.C. 20549

                   -------------------------------------------


                                    FORM 8-K


                                 CURRENT REPORT

                       Pursuant to Section 13 or 15(d) of
                       the Securities Exchange Act of 1934



                                 Date of Report
                       (Date of earliest event reported):

                                   May 5, 1999

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                              THERMO TERRATECH INC.
             (Exact name of Registrant as specified in its charter)


Delaware                        1-9549                    04-2925807
(State or other               (Commission              (I.R.S. Employer
jurisdiction of               File Number)             Identification Number) 
incorporation or
organization)


81 Wyman Street
Waltham, Massachusetts                                      02454-9046
(Address of principal executive offices)                    (Zip Code)


                                 (781) 622-1000
                         (Registrant's telephone number
                              including area code)












Item 5.     Other Events

      On May 5, 1999,  Thermo  Electron  Corporation  ("Thermo  Electron"),  the
Registrant's  parent  corporation,  and the  Registrant  issued  press  releases
stating  that  the  Registrant  may be  merged  into and  become a wholly  owned
subsidiary of Thermo  Electron.  Public  shareholders  of the  Registrant  would
receive  shares of common stock of Thermo  Electron in exchange for their shares
of the common stock of the Registrant.

      In  addition,  the  press  releases  discussed   modifications  to  Thermo
Electron's previously announced plan to merge ThermoRetec  Corporation ("Retec")
and The Randers Killam Group Inc.  ("Randers"),  each  majority-owned,  publicly
traded subsidiaries of the Registrant,  into the Registrant. Each of Randers and
Retec may now be merged  into and become  wholly  owned  subsidiaries  of Thermo
Electron.  Public  shareholders  of Randers  and Retec would  receive  shares of
common stock of Thermo Electron in exchange for their shares of the common stock
of Randers and Retec, respectively.

      The completion of these  transactions  is subject to numerous  conditions,
including  the  establishment  of prices and exchange  ratios,  confirmation  of
anticipated  tax  consequences,  approval  by  the  directors  of  each  of  the
Registrant,  Randers,  and Retec,  including the  independent  directors of such
companies,  negotiation and execution of definitive  purchase and sale or merger
agreements,   clearance  by  the  Securities   and  Exchange   Commission  of  a
registration  statement and proxy materials regarding the proposed transactions,
and, where  appropriate,  receipt of fairness  opinions from investment  banking
firms.



Item 7.     Financial Statements, Pro Forma Financial Information and Exhibits

      (a)    Financial Statements of Business Acquired: not
            applicable.

      (b)   Pro Forma Financial Information: not applicable.

      (c)   Exhibits: not applicable.











                                    SIGNATURE



      Pursuant to the  requirements of the Securities  Exchange Act of 1934, the
Registrant  has duly  caused  this  report  to be  signed  on its  behalf by the
undersigned, thereunto duly authorized, on this 12th day of May, 1999.



                                        THERMO TERRATECH INC.


                                        By:  /s/ Theo Melas-Kyraizi
                                             Theo Melas-Kyriazi
                                             Chief Financial Officer