Exhibit 11.1 CLEAN HARBORS, INC. AND SUBSIDIARIES COMPUTATION OF NET INCOME PER SHARE FOR THE FIRST QUARTER ENDED MARCH 31, 1995 (in thousands) Three Months Ended March 31, ---------------------- 1995 1994 --------- -------- Net income $ (590) $ 597 Less preferred dividends accrued (111) 105 ------- ------ Adjusted net income $ (701) $ 492 ====== ====== Earning per common and common equivalent share: Weighted average number of shares outstanding 9,431 9,428 Incremental shares for stock options under treasury stock method 14 287 ------ ------ Weighted average number of common and common equivalent shares outstanding 9,445 9,715 ====== ====== Net earnings per common and common equivalent share $ (.07) $ .05 ====== ====== Earnings per common and common equivalent share - assuming full dilution: Weighted average number of shares outstanding 9,431 9,428 Incremental shares for stock options under treasury stock method 14 287 ------ ------ Weighted average number of common and common equivalent shares outstanding - assuming full dilution 9,445 9,715 ====== ====== Net earnings per common and common equivalent share - assuming full dilution $ (.07) $ .05 ====== ====== (17)