<ARTICLE>           5
<LEGEND>
THIS SCHEDULE CONTAINS SUMMARY FINANCIAL INFORMATION EXTRACTED FROM THERMO
TERRATECH INC.'S QUARTERLY REPORT ON FORM 10-Q FOR THE PERIOD ENDED OCTOBER 2,
1999 AND IS QUALIFIED IN ITS ENTIRETY BY REFERENCE TO SUCH FINANCIAL STATEMENTS.
</LEGEND>
<MULTIPLIER>        1,000

                              
<PERIOD-TYPE>                                 6-MOS
<FISCAL-YEAR-END>                             APR-01-2000
<PERIOD-END>                                  OCT-02-1999
<CASH>                                                  3,888
<SECURITIES>                                                0
<RECEIVABLES>                                          57,999
<ALLOWANCES>                                            3,327
<INVENTORY>                                             2,359
<CURRENT-ASSETS>                                      144,471
<PP&E>                                                135,248
<DEPRECIATION>                                         62,850
<TOTAL-ASSETS>                                        319,166
<CURRENT-LIABILITIES>                                 120,425
<BONDS>                                               120,036
<PREFERRED-MANDATORY>                                       0
<PREFERRED>                                                 0
<COMMON>                                                1,958
<OTHER-SE>                                             47,715
<TOTAL-LIABILITY-AND-EQUITY>                          319,166
<SALES>                                                     0
<TOTAL-REVENUES>                                      153,944
<CGS>                                                       0
<TOTAL-COSTS>                                         121,830
<OTHER-EXPENSES>                                       54,317
<LOSS-PROVISION>                                          217
<INTEREST-EXPENSE>                                      4,465
<INCOME-PRETAX>                                       (47,332)
<INCOME-TAX>                                              241
<INCOME-CONTINUING>                                   (43,887)
<DISCONTINUED>                                              0
<EXTRAORDINARY>                                             0
<CHANGES>                                                   0
<NET-INCOME>                                          (43,887)
<EPS-BASIC>                                           (2.30)
<EPS-DILUTED>                                           (2.30)