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                                                                     EXHIBIT 3.6

                          CERTIFICATE OF INCORPORATION

                                       OF

                                  BIOCIDE INC.

     The undersigned, being of legal age, in order to form a corporation under
and pursuant to the laws of the State of Delaware, does hereby set forth as
follows:

          FIRST: The name of the corporation is:

                                  BIOCIDE INC.

          SECOND: The address of the initial registered and principal office of
     this corporation in this state is c/o United Corporate Services, Inc., 15
     East North Street, in the City of Dover, County of Kent, State of Delaware
     19901 and the name of the registered agent at said address is United
     Corporate Services, Inc.

          THIRD: The purpose of the corporation is to engage in any lawful act
     or activity for which corporation may be organized under the corporation
     laws of the State of Delaware.

          FOURTH: The corporation shall be authorized to issue the following
     shares:



CLASS                                                NUMBER OF SHARES   PAR VALUE
- -----                                                ----------------   ---------
                                                                  
COMMON.............................................       3,000           $1.00


          FIFTH: The name and address of the incorporator are as follows:



NAME                                                       ADDRESS
- ----                                                       -------
                                              
Ray A. Barr....................................  10 Bank Street
                                                 White Plains, New York 10606


          SIXTH: The following provisions are inserted for the management of the
     business and for the conduct of the affairs of the corporation, and for
     further definition, limitation and regulation of the powers of the
     corporation and of its directors and stockholders:

             (1) The number of directors of the corporation shall be such as
        from time to time shall be fixed by, or in the manner provided in the
        by-laws. Election of directors need not be by ballot unless the By-Laws
        so provide.

             (2) The Board of Directors shall have power without the assent or
        vote of the stockholders:

                (a) To make, alter, amend, change, add to or repeal the By-Laws
           of the corporation; to fix and vary the amount to be reserved for any
           proper purpose; to authorize and cause to be executed mortgages and
           liens upon all or any part of the property of the corporation; to
           determine the use and disposition of any surplus or net profits; and
           to fix the time for the declaration and payment of dividends.

                (b) To determine from time to time whether, and to what times
           and places, and under what conditions the accounts and books of the
           corporation (other than the stock ledger) or any of them, shall be
           open to the inspection of the stockholders.

             (3) The directors in their discretion may submit any contract or
        act for approval or ratification at any annual meeting of the
        stockholders, at any meeting of the stockholders called for the purpose
        of considering any such act or contract, or through a written consent in
        lieu of a meeting in accordance with the requirements of the General
        Corporation Law of Delaware as amended from time to time, and any
        contract or act that shall be so approved or be so ratified by the vote
        of the holders of a majority of the stock of the corporation which is
        represented in
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        person or by proxy at such meeting, (or by written consent whether
        received directly or through a proxy) and entitled to vote thereon
        (provided that a lawful quorum of stockholders be there represented in
        person or by proxy) shall be as valid and as binding upon the
        corporation and upon all the stockholders as though it had been
        approved, ratified, or consented to by every stockholder of the
        corporation, whether or not the contract or act would otherwise be open
        to legal attack because of directors' interest, or for any other reason.

             (4) In addition to the powers and authorities hereinbefore or by
        statute expressly conferred upon them, the directors are hereby
        empowered to exercise all such powers and do all such acts and things as
        may be exercised or done by the corporation; subject, nevertheless, to
        the provisions of the statutes of Delaware, of this certificate, and to
        any by-laws from time to time made by the stockholders; provided,
        however, that no by-laws so made shall invalidate any prior act of the
        directors which would have been valid if such by-law had not been made.

          SEVENTH: No director shall be liable to the corporation or any of its
     stockholders for monetary damages for breach of fiduciary duty as a
     director, except with respect to (1) a breach of the director's duty of
     loyalty to the corporation or its stockholders, (2) acts or omissions not
     in good faith or which involve intentional misconduct or a knowing
     violation of law, (3) liability under Section 174 of the Delaware General
     Corporation Law or (4) a transaction from which the director derived an
     improper personal benefit, it being the intention of the foregoing
     provision to eliminate the liability of the corporation's directors to the
     corporation or its stockholders to the fullest extent permitted by Section
     102(b)(7) of the Delaware General Corporation Law, as amended from time to
     time. The corporation shall indemnify to the fullest extent permitted by
     Sections 102(b)(7) and 145 of the Delaware General Corporation Law, as
     amended from time to time, each person that such Sections grant the
     corporation the power to indemnify.

          EIGHTH: Whenever a compromise or arrangement is proposed between this
     corporation and its creditors or any class of them and/or between this
     corporation and its stockholders or any class of them, any court of
     equitable jurisdiction within the State of Delaware, may, on the
     application in a summary way of this corporation or of any creditor or
     stockholder thereof or on the application of any receiver or receivers
     appointed for this corporation under the provisions of Section 291 of Title
     8 of the Delaware Code or on the application of trustees in dissolution or
     of any receiver or receivers appointed for this corporation under the
     provisions of Section 279 Title 8 of the Delaware Code order a meeting of
     the creditors or class of creditors, and/or of the stockholders or class of
     stockholders of this corporation, as the case may be, to be summoned in
     such manner as the said court directs. If a majority in number representing
     three-fourths ( 3/4) in value of the creditors or class of creditors, and/
     or of the stockholders or class of stockholders of this corporation, as the
     case may be, agree to any compromise or arrangement and to any
     reorganization of this corporation as consequence of such compromise or
     arrangement, the said compromise or arrangement and the said reorganization
     shall, if sanctioned by the court to which the said application has been
     made, be binding on all the creditors or class of creditors, and/or on all
     the stockholders or class of stockholders, of this corporation, as the case
     may be, and also on this corporation.

          NINTH: The corporation reserves the right to amend, alter, change or
     repeal any provision contained in this certificate of incorporation in the
     manner now or hereafter prescribed by law, and all rights and powers
     conferred herein on stockholders, directors and officers are subject to
     this reserved power.

     IN WITNESS WHEREOF, the undersigned hereby executes this document and
affirms that the facts set forth herein are true under the penalties of perjury
this twenty-first day of January, 1997.

                                          /s/ RAY A. BARR
                                          --------------------------------------
                                          Ray A. Barr, Incorporator

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