AMENDING AGREEMENT

          THIS AGREEMENT made as of the l0th day of December, 1993

AMONG

          WAINOCO OIL CORPORATION, a body corporate having offices in the City
          of Houston, in the State of Texas, one of the United States of
          America ("Wainoco")

                                      - and -

          BANK OF MONTREAL, a Chartered Bank with head offices in the City of
          Montreal, in the Province of Quebec and having an office in the City
          of Calgary, in the Province of Alberta ("BMO")

                                      - and -

          MORGAN BANK OF CANADA, a Chartered Bank with head offices in the City
          of Toronto, in the Province of Ontario ("Morgan")


          WHEREAS Wainoco, BMO and Morgan entered into an Amended and Restated
Loan Agreement dated October 2, 1991 as amended by a Letter Agreement dated
October 2, 1991, an Amending Agreement dated December 31, 1991, a Letter
Agreement date January 15, 1992, an Amending Agreement dated March 2, 1992, an
Amending Agreement dated April 29, 1992, an Amending Agreement dated May 29,
1992, an Amending Agreement dated June 12, 1992, an Amending Agreement dated
June 30, 1992, an Amending Agreement dated July 31, 1992, an Amending Agreement
dated August 14, 1992, an Amending Agreement dated May 10, 1993 and a Letter
Agreement dated August 12, 1993 (collectively, the "Loan Agreement");

          AND WHEREAS the parties wish to amend the Loan Agreement as herein
provided;

          NOW THEREFORE THIS AGREEMENT WITNESSES that, in consideration of the
sum of one dollar ($1.00) and other good and valuable consideration, receipt
and sufficiency of which is hereby acknowledged, the parties hereto agree as
follows:

1.   Capitalized terms used herein shall, unless otherwise defined, have the
     meanings given to them in the Loan Agreement.

2.   Section 1 of the Loan Agreement is hereby amended as follows:

     (a)  Paragraph 1(u) is deleted in its entirety and replaced by the
          following:

          "(u) "Debentures" shall mean the Subordinated Debentures and the
               Convertible Subordinated Debentures;";

     (b)  the following is added after Paragraph 1(fff) as a new Paragraph
          l(fff.1):

          "(fff.1)  "Subordinated Debentures" means the 10 3/4% subordinated
                    debentures issued, authenticated and delivered under the
                    Indenture dated as of October 1, 1978 between Wainoco and
                    First City National Bank of Houston;" and

     (c)  the following is added after Paragraph 1(r) as a new Paragraph 1(r.
          l):

          "(r.1)    "Convertible Subordinated Debentures" means the 7 3/4 %
                    convertible subordinated debentures issued, authenticated
                    and delivered or to be issued, authenticated and delivered
                    under the Indenture dated as of June 1, 1989 between
                    Wainoco and Texas Commerce Trust Company of New York;".

3.   Section 3 of the Loan Agreement is hereby amended by adding the following
     at the end of the current Paragraph 3(a)(i):

     "Notwithstanding anything to the contrary hereintofore expressed or
     implied, however, during any Libor Interest Period in which:

     (A)  the aggregate Outstandings exceed $22,500,000 and any amounts remain
          outstanding under any of the Subordinated Debentures, or

     (B)  the aggregate Outstandings exceed $27,500,000, and for so long as
          such excess exists, each Libor Loan shall bear interest on the
          unpaid principal amount thereof until payment in full thereof at a
          rate per annum equal to the sum of the rate otherwise applicable
          thereto pursuant to the preceding portions of this Paragraph 3(a)(i)
          plus one half percent (1/2%) per annum."

4.   Section 3 of the Loan Agreement is hereby further amended by adding the
     following at the end of the current Paragraph 3(a)(ii):

          "Notwithstanding anything to the contrary hereintofore expressed or
          implied, however, during any period of time in which:

     (A)  the aggregate Outstandings exceed $22,500,000 and any amounts remain
          outstanding under any of the Subordinated Debentures, or
     (B)  the aggregate outstandings exceed $27,500,000,

     and for so long as such excess exists, each Floating Rate Loan shall bear
     interest on the unpaid principal amount thereof until payment in full
     thereof at a rate per annum equal to the sum of the rate otherwise
     applicable thereto pursuant to the preceding portions of this Paragraph
     3(a)(ii) plus one half percent (l/2%) per annum."
5.   Section 6 of the Loan Agreement is hereby amended by adding the following
     at the end of the current Paragraph 6(b):

     "Notwithstanding anything to the contrary hereintofore expressed or
     implied, however, the Bankers' Acceptance fee payable to the Banks by
     Wainoco for any Bankers' Acceptance issued at a time when:

     (A)  the aggregate Outstandings exceed $22,500,000 and any amounts remain
          outstanding under any of the Subordinated Debentures, or
     (B)  the aggregate Outstandings exceed 27,500,000,

     shall be equal to the fee otherwise applicable thereto pursuant to the
     preceding portions of this Paragraph 6(b) plus one half percent (1/2%)
     per annum."
6.   Section 7 of the Loan Agreement is hereby amended by adding the following
     at the end of the current Paragraph 7(g):

     "Notwithstanding anything to the contrary hereintofore expressed or
     implied, however, the fee payable by Wainoco upon the issuance of any
     Commercial Letter of Credit issue of at a time when:

     (A)  the aggregate Outstandings exceed $22,500,000 and any amounts remain
          outstanding under any of the Subordinated Debentures, or

     (B)  the aggregate Outstandings exceed $27,500,000,

     shall be equal to the fee otherwise applicable thereto pursuant to the
     preceding portions of this Paragraph 7(g) plus one half percent (1/2%)
     per annum."

7.   Section 9 of the Loan Agreement is hereby amended by adding the following
     after Paragraph 9(a.1) as a new Paragraph 9(a.2):

          "(a.2)    Notwithstanding anything to the contrary herein expressed
                    or implied, effective as of December 10, 1993 the
                    Borrowing Base shall be amended to the amount of Thirty
                    Seven Million Five Hundred Thousand Canadian Dollars (Cdn.
                    $37,500,000)."

8.   This Agreement may be executed in counterpart and the number of
     counterparts read together shall form this Agreement.

9.   The parties hereby ratify and confirm the terms of the Loan Agreement,
     subject to the specific amendments contained herein.
     IN WITNESS WHEREOF the parties hereto have executed this Amending
Agreement as of the day first written above.

                                        WAINOCO OIL CORPORATION

                                        Per: /s/ Julie H. Edwards


                                        BANK OF MONTREAL

                                        Per: /s/ Robert Roberts

                                        
                                        MORGAN BANK OF CANADA

                                        Per: /s/ Stephen B. King