AMENDMENT NO. 3 TO CREDIT AND GUARANTY AGREEMENT

          AMENDMENT dated as of June 30, 1992 among WAINOCO OIL & GAS COMPANY
(the "Borrower"), WAINOCO OIL CORPORATION ("Wainoco"), the BANKS listed on the
signature pages hereof (the "Banks") and MORGAN GUARANTY TRUST COMPANY OF NEW
YORK, as Agent (the "Agent").

                                    WITNESSETH:

          WHEREAS, the parties hereto have heretofore entered into a Credit and
Guaranty Agreement dated as of October 4, 1991, as amended by Amendment No. 1
dated as of December 31, 1991 and by Amendment No. 2 dated as of June 24, 1992
(as so amended, the "Agreement"); and

          WHEREAS, the parties hereto desire to amend the Agreement in the
manner set forth herein.

          NOW, THEREFORE, the parties hereto agree as follows:

          SECTION 1. Definitions; References. Unless otherwise specifically
defined herein, each term used herein which is defined in the Agreement shall
have the meaning assigned to such term in the Agreement. Each reference to
"hereof", "hereunder", "herein" and "hereby" and each other similar reference
and each reference to "this Agreement" and each other similar reference
contained in the Agreement shall from and after the date hereof refer to the
Agreement as amended hereby.

          SECTION 2. Amendment of Section 1.01 of the Agreement. (A) The
following defined terms in Section 1.01 are redefined as follows:

          "Borrowing Base" means (i) on any date prior to the Determination
Date next succeeding the date of delivery of the Second Borrower Engineer's
Report, $20,000,000 less the Net Sales Proceeds of any of the Borrower
Engineered Properties covered by the Second Borrower Engineer's Report sold or
transferred on or after the date of such Engineer's Report, and (ii) on any
date on or after such Determination Date, the amount notified to the Borrower
by the Agent pursuant to Section 2.01(b) as the amount of the Borrowing Base on
the most recent Determination Date falling on or prior to such date less the
Net Sales Proceeds of any of the Borrower Engineered Properties covered by the
then most recent Borrower Engineer's Report sold or transferred on or after the
date of such Engineer's Report (unless such sale or transfer is otherwise taken
into account in the determination of the Borrowing Base for such date). The
Borrower will promptly notify the Agent of the amount of any sale or other
transfer of Borrower Engineered Properties which requires a reduction in the
Borrowing Base pursuant to this Section.

          "Maturity Date" means the Quarterly Date falling in December, 1998.

          "Quarterly Date" means the last Euro-Dollar Business Day of each
March, June, September and December.

          "Termination Date" means the Quarterly Date falling in December,
1993.

          (B) The following defined term is hereby added to Section 1.01:

          "Second Borrower Engineer's Report" means the report of Ryder Scott
          Company dated January 1, 1992 delivered to the Agent pursuant to
          Section 5.14(a) of the Agreement.

          SECTION 3. Amendment of Section 2.05 of the Agreement. (A) In Section
2.05(a) of the Agreement, the first sentence is amended to read as follows:

          (a) Each Domestic Loan shall bear interest on the outstanding
          principal amount thereof, for each day from the date such Loan is
          made until it becomes due, at a rate per annum equal to (i) the sum
          of 1/4 of 1% plus the Base Rate for such day, if such day falls prior
          to the Termination Date; and (ii) the sum of 1/2 of 1% plus the Base
          Rate for such day, if such day falls on or after the Termination
          Date.

          (B) In Section 2.05(b), the defined term "Margin" is redefined as
          follows:

          "Margin" means (i) 1 1/4% prior to the Termination Date; and (ii) 1
          1/2% on and after the Termination Date.

          SECTION 4. Amendment of Section 2.06(b) of the Agreement. In Section
2.06(b) of the Agreement, the first sentence is amended to read as follows:

          (b) Commitment Fee. During the Revolving Credit Period, the Borrower
          shall pay to the Agent for the accounts of the Banks ratably in
          proportion to their Commitments a commitment fee at the rate of 3/8
          of 1% per annum on the daily average amount by which the aggregate
          amount of the Commitments exceeds the aggregate outstanding principal
          amount of the Loans.

          SECTION 5. Amendment of Section 5.07 of the Agreement. Section 5.07
is amended to read as follows:

          SECTION 5.07. Debt. Neither Wainoco nor any Subsidiary will, after
          the date hereof, create, incur or assume any Debt other than (i)
          under the Financing Documents, (ii) in the case of Wainoco, not to
          exceed Cnd.$40,000,000 under the Wainoco Credit Agreement, (iii) in
          the case of FHI, not to exceed U.S.$50,000,000 under the Frontier
          Debt, (iv) in the case of Wainoco, loans or advances by any Person
          (not being a Subsidiary) to it for working capital purposes in an
          aggregate amount not exceeding $5,000,000 at any one time, (v) loans
          or advances by Wainoco to a Subsidiary or by a Subsidiary to Wainoco,
          (vi) in the case of Wainoco, unsecured notes not to exceed
          $100,000,000, (vii) in the case of Wainoco, not to exceed $46,000,000
          under the Wainoco Convertible Debentures, and (viii) in the case of
          Wainoco, not to exceed $17,500,000 under the Wainoco Subordinated
          Debentures.

          SECTION 6. Reduction of the Commitments. On the effective date of
this Amendment, the Commitments shall be ratably reduced by $7,500,000.

          SECTION 7. Participation Fee. On the effective date of this
Amendment, the Borrower shall pay to the Agent for the account of the Banks
ratably in proportion to their respective Commitments on and as of such date
participation fees in an amount of 1/8 of 1% of the aggregate amount of such
Commitments.

          SECTION 8. Effectiveness of this Amendment. This Amendment shall
become effective on the date that each of the following shall have been
satisfied (or waived in accordance with Section 10.06 of the Agreement):

          (a) receipt by the Agent of duly executed counterparts hereof signed
          by the Borrower and the Banks (or, in the case of any party as to
          which an executed counterpart shall not have been received, the Agent
          shall have received telegraphic, telex or other written confirmation
          from such party of execution of a counterpart hereof by such party);

          (b) repayment in full of the amount by which the aggregate
          outstanding principal amount of the Loans on the date hereof exceeds
          $20,000,000;

          (c) payment in full to the Agent of the participation fees described
          in Section 7 of this Amendment;

          (d) receipt by the Agent of an opinion of Andrews & Kurth, L.L.P.,
          counsel for the Borrower and Wainoco, satisfactory in form and scope
          to the Agent;

          (e) receipt by the Agent of an opinion of Gordon, Arata, McCollam &
          Duplantis, special Louisiana counsel for the Borrower, to the effect
          that the execution, delivery and performance of this Amendment has no
          adverse effect on its opinion dated October 11, 1991 and delivered to
          the Banks and the Agent pursuant to Section 3.01(d) of the Agreement;

          (f) receipt by the Agent of an opinion of White & Morse, special
          Mississippi counsel for the Borrower, to the effect that the
          execution, delivery and performance of this Amendment has no adverse
          effect on its opinion dated October 11, 1991 and delivered to the
          Banks and the Agent pursuant to Section 3.01(e) of the Agreement; and

          (g) receipt by the Agent of a certificate of the Treasurer of the
          Borrower attesting to the fact that the representation and warranties
          of the Borrower and of Wainoco contained in the Financing Documents
          are true on and as of such date.

          SECTION 9. Governing Law. This Amendment shall be governed by and
construed in accordance with the laws of the State of New York.

          SECTION 10. Counterparts. This Amendment may be signed in any number
of counterparts, each of which shall be an original, with the same effect as if
the signatures thereto and hereto were upon the same instrument.
          IN WITNESS WHEREOF, the parties hereto have caused this Amendment to
be duly executed as of the date first above written.

                              WAINOCO OIL & GAS COMPANY

                              By: /s/ Julie H. Edwards
                              Title: Vice President,
                                Secretary & Treasurer

                              WAINOCO OIL CORPORATION

                              By: /s/ Julie H. Edwards
                              Title: Vice President,
                                Secretary & Treasurer

                              MORGAN GUARANTY TRUST COMPANY
                                OF NEW YORK

                              By: /s/ Peter Rugg
                              Title: Vice President

                              J.P. MORGAN DELAWARE

                              By: /s/ D.J. Morris
                              Title: Vice President

                              BANK OF MONTREAL

                              By: /s/ Frank J. Techar
                              Title: Director

                              MORGAN GUARANTY TRUST COMPANY
                                OF NEW YORK, as Agent

                              By: /s/ Peter Rugg
                              Title: Vice President