Exhibit 10.30
                      SENIOR EXECUTIVE EMPLOYMENT AGREEMENT

         AMENDMENT NO. 1

                  This Amendment No. 1, dated the 25 day of April, 2000, amends
the Senior Executive Employment Agreement dated June 2, 1995 between Sybron
Chemicals Inc. and Richard M. Klein (the "Agreement").  All terms capitalized
but not otherwise defined herein shall have the meaning ascribed to them in the
Agreement.

                  Pursuant  to the  approval  of the Board of  Directors  of the
Corporation of even date herewith, the Agreement is hereby amended as follows:

                  1.       The Agreement is hereby amended by replacing all
references to "NASDAQ" with "The American Stock Exchange".

                  2.       The Agreement is hereby amended by replacing all
references to "Annual Incentive Compensation Plan" with "Executive Bonus Plan".

                  3.       The Agreement is hereby amended by the addition of
the following Paragraph 12(c):

                           "(c) The value of each incentive  award payable under
                           this  Paragraph 12 shall be  determined in accordance
                           with  the  provisions  of  Section   7(g)(4)  of  the
                           Corporation's Executive Bonus Pan, as amended. To the
                           extent all or a portion of the Executive's  Incentive
                           Compensation awarded during the preceding three years
                           was paid in shares of the  Corporation's  stock,  the
                           portion  of  the  amount  payable  to  the  Executive
                           pursuant   to   Paragraph    12(b)(2)(ii)   hereunder
                           attributable to such stock awards shall be calculated
                           by  multiplying  (i) the  average  number  of  shares
                           awarded to the Executive  during such preceding three
                           years,   by  (ii)  the  fair  market   value  of  the
                           Corporation's  shares as of the date of the Change in
                           Control."

                  4.       Paragraph 13(d) of the Agreement is hereby amended by
replacing the reference therein to "90 days" with "180 days".

                  5.       The Agreement is hereby amended by the addition of
the following Paragraph 13(f):

                           "(f) The value of each incentive  award payable under
                           this  Paragraph 13 shall be  determined in accordance
                           with  the  provisions  of  Section   7(g)(4)  of  the
                           Corporation's Executive Bonus Plan, as amended."

                  6.       The Agreement is hereby  amended by the addition of
the following Paragraph 13A:

                           "13A.  Excess Parachute Gross-up Payments.
                                  ----------------------------------

                           (a) In the  event  any  amounts  payable  under  this
                           Agreement  and  under any other  plan,  agreement  or
                           arrangement  by which  the  Executive  is to  receive
                           payments  in the  nature  of  compensation  from  the
                           Corporation constitute "excess parachute payments" as
                           that term is defined for  purposes of Section 280G of
                           the Internal  Revenue  Code of 1986,  as amended (the
                           "Code") and Treasury Regulations promulgated pursuant
                           thereto,  the Executive  shall be entitled to receive
                           additional cash payments  ("Gross-Up  Payments") such
                           that,  after payment of all federal,  state and local
                           income  taxes and federal  excise taxes on the excess
                           parachute payments and on the Gross-Up  Payments,  he
                           will have a net  amount  equal to the amount he would
                           have received  under the terms of this  Agreement and
                           under  any  other  plan,   agreement  or  arrangement
                           pursuant  to  which  the   Executive  is  to  receive
                           payments  in the  nature  of  compensation  from  the
                           Corporation (but not including the Gross-Up Payments)
                           if no portion of such payments  and/or  benefits were
                           treated as excess parachute  payments for purposes of
                           Code Section 280G.

                           (b) The initial  determination  of whether a Gross-Up
                           Payment is required  and the amount of such  Gross-Up
                           Payments shall be made by the Corporation's regularly
                           engaged certified public accountants (the "Accounting
                           Firm").  The Accounting  Firm shall provide  detailed
                           calculations  to the  Corporation  and the  Executive
                           within 30  business  days of being  requested  by the
                           Executive to make a Gross-Up  Payment  determination.
                           If the  Accounting  Firm  determines  that a Gross-Up
                           Payment  is  required,   the   Gross-Up   Payment  so
                           determined  shall be paid  within five days after the
                           receipt of the Accounting  Firm's  determination.  If
                           the  Accounting  Firm  determines  that  no  Gross-Up
                           Payment  is  payable  to the  Executive,  it shall so
                           advise the Executive in writing. If,  notwithstanding
                           the  Accounting  Firm's  initial  determination,  the
                           Internal  Revenue  Service,  any applicable  state or
                           local tax authority or any court having  jurisdiction
                           over this matter  determines  that the  Executive was
                           the  recipient of excess  parachute  payments  and/or
                           that the  Executive is required to pay an excise tax,
                           the applicable  Gross-Up Payment or the amount of any
                           underpayment  of  Gross-Up  Payments  shall  be  paid
                           promptly by the Corporation to the Executive.

                  7.       The Agreement in all other respects is hereby
ratified and confirmed.

                  IN WITNESS WHEREOF, the parties have executed this Amendment
No. 1 as of the date first set forth above.

                                                   SYBRON CHEMICALS INC.


                                             By:   /s/ Richard M. Klein
                                                   ----------------------------
                                                       Richard M. Klein