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                                                                     Exhibit 4.1

                       THIRD AMENDMENT TO RIGHTS AGREEMENT

         THIS THIRD AMENDMENT TO RIGHTS AGREEMENT (this "Amendment") is made as
of the 13th day of November, 2000, by and between SYSTEMONE TECHNOLOGIES INC., a
Florida corporation (the "Company"), and CONTINENTAL STOCK TRANSFER & TRUST
COMPANY (the "Rights Agent").

                                    RECITALS

         WHEREAS, on October 1, 1998, the Board of Directors of the Company
authorized and declared a dividend distribution of one Right for each share of
common stock, $.001 par value, of the Company outstanding at the close of
business on October 8, 1998;

         WHEREAS, the Company and the Rights Agent entered into a certain Rights
Agreement, dated as of October 1, 1998 (the "Rights Agreement"), providing,
among other things, for the issuance of the Rights (all capitalized terms used
in this Amendment and not otherwise defined herein shall have the meanings
ascribed to such terms in the Rights Agreement);

         WHEREAS, the Company and the Rights Agent amended the Rights Agreement
pursuant to the First Amendment to Rights Agreement, dated as of May 24, 2000;

         WHEREAS, the Company and the Rights Agent amended the Rights Agreement
pursuant to the Second Amendment to Rights Agreement, dated as of August 7,
2000; and

         WHEREAS, the Board of Directors of the Company has approved a third
amendment to the Rights Agreement as hereinafter set forth, pursuant to a
unanimous written consent dated on or about the date hereof.

         NOW, THEREFORE, in consideration of the premises and for other good and
valuable consideration, the receipt and sufficiency of which are hereby
acknowledged, the parties hereto agree as follows:

         1. Section 1 of the Rights Agreement is hereby amended by deleting the
definition of "Acquiring Person" set forth in subsection (a) thereof in its
entirety and substituting therefor a new definition of "Acquiring Person" to
read as follows:

         "Acquiring Person" shall mean any Person who or which, together with
         all Affiliates and Associates of such Person, shall be the Beneficial
         Owner of fifteen percent (15%) or more of the shares of Common Stock
         outstanding. Notwithstanding the foregoing, the term "Acquiring Person"
         shall not include (i) the Company, any Subsidiary of the Company, any
         employee benefit plan of the Company or of any Subsidiary of the
         Company, or any Person or entity organized, appointed or established by
         the Company for or pursuant to the terms of any such

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         plan, (ii) Pierre G. Mansur, unless such individual shall be the
         beneficial owner of fifty percent (50%) or more of the shares of Common
         Stock then outstanding, (iii) Hanseatic Americas LDC, unless it shall
         be the beneficial owner of forty-five percent (45%) or more of the
         shares of Common Stock then outstanding, (iv) Environmental
         Opportunities Fund II (Institutional), L.P., Environmental
         Opportunities Fund II, L.P., Environmental Opportunities Fund, L.P., or
         Environmental Opportunities Fund II (Cayman), L.P., unless such Persons
         shall be the Beneficial Owners, individually or in the aggregate, of
         thirty-five percent (35%) or more of the shares of Common Stock then
         outstanding, (v) Safety-Kleen Systems, Inc., unless it shall be the
         beneficial owner of nineteen and one-half percent (19.5%) or more of
         the shares of Common Stock then outstanding, or (vi) any Person who or
         which, together with all Affiliates and Associates of such Person,
         would be an Acquiring Person solely by reason of a reduction in the
         number of issued and outstanding shares of Common Stock of the Company
         pursuant to a transaction or series of related transactions approved by
         a majority of the Independent Directors, if any, then in office and
         approved by a Supermajority Vote; provided, further, however, that in
         the event that such Person described in the foregoing clause (vi) does
         not become an Acquiring Person by reason of the foregoing clause (vi),
         such Person shall nonetheless become an Acquiring Person in the event
         such Person thereafter acquires Beneficial Ownership of an additional
         one percent (1%) of the Common Stock of the Company, unless such
         additional Common Stock ownership results solely from a subsequent
         reduction in the number of issued and outstanding shares of Common
         Stock of the Company.

         2. Except as specifically amended hereby, the Rights Agreement is and
remains unmodified and in full force and effect and is hereby ratified and
confirmed.

         3. This Amendment shall be deemed a contract made under the laws of the
State of Florida and for all purposes shall be governed by and construed in
accordance with the laws of such State applicable to contracts made and to be
performed entirely within such State.

         4. This Amendment may be executed in counterparts, each of which shall
for all purposes be deemed to be an original, and shall constitute but one and
the same instrument.

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         IN WITNESS WHEREOF, the parties hereto have caused this Amendment to be
duly executed as of the date first above written.

                                                    SYSTEMONE TECHNOLOGIES INC.


                                                    By:
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                                                    CONTINENTAL STOCK TRANSFER &
                                                    TRUST COMPANY


                                                    By:
                                                       ------------------------


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