<TABLE> <S> <C>

<PAGE>
<ARTICLE> 5
<RESTATED>
<CIK> 0000861184
<NAME> WAHLCO ENV. SYSTEMS
<MULTIPLIER> 1,000

<S>                             <C>                     <C>                     <C>                     <C>
<C>
<PERIOD-TYPE>                   YEAR                   YEAR                   3-MOS                   6-MOS
9-MOS
<FISCAL-YEAR-END>                          DEC-31-1995             DEC-31-1996             DEC-31-1996             DEC-31-1996
             DEC-31-1996
<PERIOD-END>                               DEC-31-1995             DEC-31-1996             MAR-31-1996             JUN-30-1996
             SEP-30-1996
<CASH>                                           5,147                   2,903                   3,638                   2,764
                   2,119
<SECURITIES>                                         0                       0                       0                       0
                       0
<RECEIVABLES>                                   15,935                  12,069                  13,273                  11,292
                  11,109
<ALLOWANCES>                                         0                       0                       0                       0
                       0
<INVENTORY>                                      8,711                   4,738                   8,432                   7,808
                   6,383
<CURRENT-ASSETS>                                38,212                  23,223                  32,830                  29,981
                  26,834
<PP&E>                                           5,921                   5,190                   5,657                   5,268
                   5,060
<DEPRECIATION>                                       0                       0                       0                       0
                       0
<TOTAL-ASSETS>                                  46,519                  29,820                  40,833                  37,698
                  34,290
<CURRENT-LIABILITIES>                           25,499                  18,060                  21,079                  23,182
                  21,256
<BONDS>                                              0                       0                       0                       0
                       0
<PREFERRED-MANDATORY>                                0                       0                       0                       0
                       0
<PREFERRED>                                          0                       0                       0                       0
                       0
<COMMON>                                           176                     176                     176                     176
                     176
<OTHER-SE>                                       7,191                 (2,996)                   6,255                   2,183
                   1,258
<TOTAL-LIABILITY-AND-EQUITY>                    46,519                  29,820                  40,833                  37,698
                  34,290
<SALES>                                         49,558                  36,346                  11,634                  19,504
                  26,880
<TOTAL-REVENUES>                                60,100                  43,051                  13,388                  23,507
                  32,630
<CGS>                                           43,421                  32,685                   9,210                  16,956
                  23,286
<TOTAL-COSTS>                                   51,520                  39,097                  10,576                  20,684
                  28,564
<OTHER-EXPENSES>                                21,116                  16,899                   3,835                   8,799
                  11,804
<LOSS-PROVISION>                                     0                       0                       0                       0
                       0
<INTEREST-EXPENSE>                             (2,125)                 (1,663)                   (375)                   (751)
                 (1,103)
<INCOME-PRETAX>                               (14,302)                (13,733)                 (1,284)                 (6,643)
                 (8,762)
<INCOME-TAX>                                   (2,950)                 (2,924)                   (474)                 (1,774)
                 (2,476)
<INCOME-CONTINUING>                           (11,352)                (10,809)                   (810)                 (4,869)
                 (6,286)
<DISCONTINUED>                                       0                       0                       0                       0
                       0
<EXTRAORDINARY>                                      0                       0                       0                       0
                       0
<CHANGES>                                            0                       0                       0                       0
                       0
<NET-INCOME>                                  (11,352)                (10,809)                   (810)                 (4,869)
                 (6,286)
<EPS-PRIMARY>                                   (0.64)                  (0.61)                  (0.05)                  (0.28)
                  (0.36)
<EPS-DILUTED>                                   (0.64)                  (0.61)                  (0.05)                  (0.28)
                  (0.36)


</TABLE>