<PAGE>   1
                                                                  EXHIBIT 10.(b)
                                                                  EXECUTION COPY




                               U.S. $100,000,000

                            364-DAY CREDIT AGREEMENT

                         Dated as of February 27, 1997

                                     Among

                         FINA OIL AND CHEMICAL COMPANY

                                  as Borrower

                                   FINA, INC.

                                  as Guarantor

                             THE BANKS NAMED HEREIN

                                    as Banks

                                   CIBC INC.
                    TEXAS COMMERCE BANK NATIONAL ASSOCIATION

                                  as Co-Agents

                       NATIONSBANC CAPITAL MARKETS, INC.

                        as Arranger & Syndication Agent

                                      and

                           NATIONSBANK OF TEXAS, N.A.

                                    as Agent





<PAGE>   2
                               TABLE OF CONTENTS

<TABLE>
<CAPTION>
       Section                                                              Page
       -------                                                              ----
       <S>          <C>                                                      <C>
                                    ARTICLE I

                        DEFINITIONS AND ACCOUNTING TERMS

       Section 1.01.  Certain Defined Terms   . . . . . . . . . . . . . . .    1
       Section 1.02.  Computation of Time Periods   . . . . . . . . . . . .   12
       Section 1.03.  Accounting Terms  . . . . . . . . . . . . . . . . . .   12
       Section 1.04.  Miscellaneous   . . . . . . . . . . . . . . . . . . .   12


                                   ARTICLE II

                        AMOUNTS AND TERMS OF THE ADVANCES

       Section 2.01.  The A Advances  . . . . . . . . . . . . . . . . . . .   13
       Section 2.02.  Making the A Advances   . . . . . . . . . . . . . . .   13
       Section 2.03.  Fees  . . . . . . . . . . . . . . . . . . . . . . . .   16
       Section 2.04.  Optional Reduction of the Commitments   . . . . . . .   16
       Section 2.05.  Repayment and Prepayment of A Advances  . . . . . . .   17
       Section 2.06.  Interest on A Advances  . . . . . . . . . . . . . . .   17
       Section 2.07.  Interest Rate Determination   . . . . . . . . . . . .   18
       Section 2.08.  The B Advances  . . . . . . . . . . . . . . . . . . .   18
       Section 2.09.  Payments, Computations; Interest on Overdue
                       Amounts. . . . . . . . . . . . . . . . . . . . . . .   21
       Section 2.10.  Consequential Losses  . . . . . . . . . . . . . . . .   22
       Section 2.11.  Increased Costs   . . . . . . . . . . . . . . . . . .   22
       Section 2.12.  Illegality  . . . . . . . . . . . . . . . . . . . . .   24
       Section 2.13.  Taxes   . . . . . . . . . . . . . . . . . . . . . . .   24
       Section 2.14.  Payments Pro Rata   . . . . . . . . . . . . . . . . .   26
       Section 2.15.  Increase of Aggregate Commitments   . . . . . . . . .   26


                                   ARTICLE III

                                   CONDITIONS

       Section 3.01.  Conditions Precedent to Effectiveness   . . . . . . .   28
       Section 3.02.  Conditions Precedent to Each A Borrowing  . . . . . .   29
</TABLE>





                                      -i-
<PAGE>   3
<TABLE>
       <S>            <C>                                                    <C>
       Section 3.03.  Conditions Precedent to Certain Borrowings  . . . . .   30
       Section 3.04.  Conditions Precedent to Each B Borrowing  . . . . . .   30

                                   ARTICLE IV

                                    GUARANTY

       Section 4.01.  Guaranty  . . . . . . . . . . . . . . . . . . . . . .   31
       Section 4.02.  Guaranty Absolute   . . . . . . . . . . . . . . . . .   31
       Section 4.03.  Waiver.   . . . . . . . . . . . . . . . . . . . . . .   32
       Section 4.04.  Subrogation   . . . . . . . . . . . . . . . . . . . .   32
       Section 4.05.  No Waiver; Remedies   . . . . . . . . . . . . . . . .   32
       Section 4.06.  Continuing Guaranty   . . . . . . . . . . . . . . . .   32



                                    ARTICLE V

                         REPRESENTATIONS AND WARRANTIES

       Section 5.01.  Corporate Existence   . . . . . . . . . . . . . . . .   33
       Section 5.02.  Corporate Power   . . . . . . . . . . . . . . . . . .   33
       Section 5.03.  Authorization and Approvals   . . . . . . . . . . . .   33
       Section 5.04.  Enforceable Obligations   . . . . . . . . . . . . . .   34
       Section 5.05.  Financial Statements  . . . . . . . . . . . . . . . .   34
       Section 5.06.  Litigation  . . . . . . . . . . . . . . . . . . . . .   35
       Section 5.07.  Regulation U; Use of Proceeds   . . . . . . . . . . .   35
       Section 5.08.  Investment Company Act  . . . . . . . . . . . . . . .   35
       Section 5.09.  ERISA   . . . . . . . . . . . . . . . . . . . . . . .   35
       Section 5.10.  Taxes   . . . . . . . . . . . . . . . . . . . . . . .   35
       Section 5.11.  Holding Company   . . . . . . . . . . . . . . . . . .   36
       Section 5.12.  Environmental Condition   . . . . . . . . . . . . . .   36
       Section 5.13.  Ownership of Borrower   . . . . . . . . . . . . . . .   36
       Section 5.14.  Guarantor's Independent Decision  . . . . . . . . . .   36


                                   ARTICLE VI

                              AFFIRMATIVE COVENANTS

       Section 6.01.  Compliance with Laws, Etc.  . . . . . . . . . . . . .   36
</TABLE>





                                      -ii-
<PAGE>   4
<TABLE>
       <S>            <C>                                                    <C>
       Section 6.02.  Reporting Requirements  . . . . . . . . . . . . . . .   37
       Section 6.03.  Use of Proceeds   . . . . . . . . . . . . . . . . . .   39
       Section 6.04.  Maintenance of Insurance  . . . . . . . . . . . . . .   39
       Section 6.05.  Preservation of Corporate Existence, Etc.   . . . . .   39
       Section 6.06.  Payment of Taxes, Etc.  . . . . . . . . . . . . . . .   39
       Section 6.07.  Visitation Rights   . . . . . . . . . . . . . . . . . . 39


                                   ARTICLE VII

                               NEGATIVE COVENANTS

       Section 7.01.  Financial Covenants   . . . . . . . . . . . . . . . .   40
       Section 7.02.  Liens, Etc.   . . . . . . . . . . . . . . . . . . . .   40
       Section 7.03.  Merger and Sale of Assets   . . . . . . . . . . . . .   40
       Section 7.04.  Agreements to Restrict Dividends and Certain
                       Transfers. . . . . . . . . . . . . . . . . . . . . .   41
       Section 7.05.  Compliance with ERISA   . . . . . . . . . . . . . . .   41
       Section 7.06.  Transactions with Affiliates  . . . . . . . . . . . .   41
       Section 7.07.  Change of Business  . . . . . . . . . . . . . . . . .   42
       Section 7.08.  Limitation on Loans, Advances and Investments   . . .   42
       Section 7.09.  Fiscal Year; Accounting Practices   . . . . . . . . .   42


                                  ARTICLE VIII

                                EVENTS OF DEFAULT

       Section 8.01.  Events of Default   . . . . . . . . . . . . . . . . .   43


                                   ARTICLE IX

         THE AGENT, THE CO-AGENTS, AND THE ARRANGER & SYNDICATION AGENT

       Section 9.01.  Authorization and Action  . . . . . . . . . . . . . .   46
       Section 9.02.  Agent's Reliance, Etc.  . . . . . . . . . . . . . . .   46
       Section 9.03.  NationsBank and Affiliates  . . . . . . . . . . . . .   46
       Section 9.04.  Bank Credit Decision  . . . . . . . . . . . . . . . .   47
       Section 9.05.  Indemnification   . . . . . . . . . . . . . . . . . .   47
       Section 9.06.  Successor Agent   . . . . . . . . . . . . . . . . . .   48
       Section 9.07.  Co-Agents; Arranger & Syndication Agent   . . . . . .   48
</TABLE>





                                     -iii-
<PAGE>   5
<TABLE>
       <S>             <C>                                                   <C>
                                    ARTICLE X

                                  MISCELLANEOUS

       Section 10.01.  Amendments, Etc.   . . . . . . . . . . . . . . . . .   48
       Section 10.02.  Notices, Etc.  . . . . . . . . . . . . . . . . . . .   49
       Section 10.03.  No Waiver; Remedies  . . . . . . . . . . . . . . . .   49
       Section 10.04.  Costs, Expenses and Taxes  . . . . . . . . . . . . .   50
       Section 10.05.  Right of Set-off   . . . . . . . . . . . . . . . . .   50
       Section 10.06.  Bank Assignments and Participations  . . . . . . . .   51
       Section 10.07.  Governing Law  . . . . . . . . . . . . . . . . . . .   53
       Section 10.08.  Interest   . . . . . . . . . . . . . . . . . . . . .   53
       Section 10.09.  Execution in Counterparts  . . . . . . . . . . . . .   54
       Section 10.10.  Survival of Agreements, Representations and
                         Warranties, Etc.   . . . . . . . . . . . . . . . .   54
       Section 10.11.  Borrower's Right to Apply Deposits   . . . . . . . .   54
       Section 10.12.  Confidentiality  . . . . . . . . . . . . . . . . . .   55
       Section 10.13.  Binding Effect   . . . . . . . . . . . . . . . . . .   55
       Section 10.14.  Entire Agreement   . . . . . . . . . . . . . . . . .   55
       Section 10.15.  Severability   . . . . . . . . . . . . . . . . . . .   56
</TABLE>





                                      -iv-
<PAGE>   6
Schedule I    -      Agent and Bank Information

Schedule II   -      Borrower and Guarantor Information

Schedule III  -      Existing Permitted Liens  (7.02)

Schedule IV   -      Certain Existing Transfer Restrictions (7.04)

Schedule V    -      Certain Loans and Investments (7.08)

Exhibit A-1   -      Form of A Note

Exhibit A-2   -      Form of B Note

Exhibit B-1   -      Notice of A Borrowing

Exhibit B-2   -      Notice of B Borrowing

Exhibit C     -      Form of Assignment and Acceptance

Exhibit D     -      Opinion of Counsel for the Borrower and the Guarantor

Exhibit E     -      Opinion of Special Counsel to Agent

Exhibit F     -      Form of Accession Agreement

Exhibit G     -      Form of Consent to Increase in Commitment





                                      -v-
<PAGE>   7
                                CREDIT AGREEMENT

                         Dated as of February 27, 1997


       This Credit Agreement dated as of February 27, 1997, is by and among the
Borrower, the Guarantor, the Agent, the Co-Agents, the Arranger & Syndication
Agent and the Banks.  In consideration of the mutual covenants and agreements
contained herein, the Borrower, the Guarantor, the Agent, the Co-Agents, the
Arranger & Syndication Agent and the Banks hereby agree as follows:


                                   ARTICLE I

                        DEFINITIONS AND ACCOUNTING TERMS

       Section 1.01.  Certain Defined Terms.  As used in this Agreement, the
following terms shall have the following meanings (such meanings to be equally
applicable to both the singular and plural forms of the terms defined):

       "A Advance" means an advance by a Bank to the Borrower as part of an A
Borrowing and refers to a Base Rate Advance or a Eurodollar Rate Advance, each
of which shall be a "Type" of A Advance.

       "A Borrowing" means a borrowing consisting of simultaneous A Advances of
the same Type to the Borrower made by each of the Banks pursuant to Section
2.01.

       "A Note" means a promissory note of the Borrower payable to the order of
any Bank, in substantially the form of Exhibit A-1 hereto, evidencing the
aggregate indebtedness of the Borrower to such Bank resulting from A Advances.

       "Accession Agreement" means an Accession Agreement in the form of
Exhibit F duly executed by the Borrower, the Guarantor, the Agent, and a New
Bank in connection with an increase in the aggregate Commitments permitted
pursuant to Section 2.15.

       "Advance" means an A Advance or a B Advance.

       "Affiliate" of any Person means any corporation, partnership, limited
liability company, limited liability partnership, joint venture or other entity
of which more than 10% of the outstanding capital stock or other equity
interests having ordinary voting power to elect a majority of the board of
directors of such corporation, partnership, limited liability company, limited
liability partnership, joint venture or other entity or others performing
similar functions (irrespective of whether or not at the time capital stock or
other equity interests of any other class or classes of such corporation,





<PAGE>   8
partnership, limited liability company, limited liability partnership, joint
venture or other entity shall or might have voting power upon the occurrence of
any contingency) is at the time directly or indirectly owned by such Person or
which owns at the time directly or indirectly more than 10% of the outstanding
capital stock or other equity interests having ordinary voting power to elect a
majority of the board of directors of such Person or others performing similar
functions (irrespective of whether or not at the time capital stock or other
equity interests of any other class or classes of such corporation,
partnership, limited liability company, limited liability partnership, joint
venture or other entity shall or might have voting power upon the occurrence of
any contingency).

       "Agent" means NationsBank of Texas, N.A. in its capacity as agent
pursuant to Article IX hereof and any successor Agent pursuant to Section 9.06.

       "Agent's Fee Letter" means the letter agreement dated as of January 24,
1997 among the Agent, the Borrower and the Guarantor.

       "Aggregate Commitment Limit" means $550,000,000.

       "Agreement" means this Credit Agreement dated as of February 27, 1997
among the Borrower, the Guarantor, the Agent, the Co-Agents, the Arranger &
Syndication Agent and the Banks, as amended or modified from time to time.

       "Applicable Lending Office" means, with respect to each Bank, such
Bank's Domestic Lending Office in the case of a Base Rate Advance and such
Bank's Eurodollar Lending Office in the case of a Eurodollar Rate Advance and,
in the case of a B Advance, the office of such Bank notified by such Bank to
the Agent as its Applicable Lending Office with respect to such B Advance.

       "Applicable Facility Fee" means, at any time the facility fee described
in Section 2.03 is to be paid, the following percentages per annum determined
as a function of the Guarantor's senior unsecured debt rating according to S&P
or Moody's, whichever is higher, on the last day of the immediately preceding
calendar quarter:

              Rating A+/A1           .04%

              Rating A/A2            .05%

              Rating A-/A3           .06%

              Rating BBB+/Baa1
              or BBB/Baa2            .08%

              Rating BBB-/Baa3       .125%

              Rating BB+/Ba1
              or below               .175%





                                      -2-
<PAGE>   9
       "Applicable Margin" means, at any time with respect to any A Advance
which is a Eurodollar Rate Advance, the following percentages determined as a
function of the Guarantor's senior unsecured debt rating according to S&P or
Moody's, whichever is higher, on the last day of the immediately preceding
calendar quarter:

              Rating A+/A1                 0.16%

              Rating A/A2                  0.17%

              Rating A-/A3                 0.185%

              Rating BBB+/Baa1
              or BBB/Baa2                  0.22%

              Rating BBB-/Baa3             0.30%

              Rating BB+/Ba1
              or below                     0.45%

       "Assignment" means an assignment and acceptance entered into by a Bank
and an Eligible Assignee, and accepted by the Agent, in substantially the form
of the attached Exhibit C.

       "B Advance" means an advance by a Bank to the Borrower as part of a B
Borrowing resulting from the auction bidding procedure described in Section
2.08.

       "B Borrowing" means a borrowing consisting of simultaneous B Advances to
the Borrower from each of the Banks whose offer to make one or more B Advances
as part of such borrowing has been accepted by the Borrower under the auction
bidding procedure described in Section 2.08.

       "B Note" means a promissory note of the Borrower payable to the order of
any Bank, in substantially the form of Exhibit A-2 hereto, evidencing the
indebtedness of the Borrower to such Bank resulting from a B Advance made to
the Borrower by such Bank.

       "B Reduction" has the meaning specified in Section 2.01.

       "Banks" means the banks listed on the signature pages hereof and each
other Person that becomes a Bank pursuant to an Assignment or an Accession
Agreement.

       "Base Rate" means a fluctuating interest rate per annum as shall be in
effect from time to time which rate per annum shall at all times be equal to
the highest of:





                                      -3-
<PAGE>   10
       (a)    the rate of interest announced publicly by NationsBank, from time
to time, as NationsBank's prime rate; or

       (b)     1/2 of one percent per annum above the Federal Funds Rate in
effect from time to time.

       "Base Rate Advance" means an A Advance which bears interest as provided
in Section 2.06(a).

       "Borrower" means Fina Oil and Chemical Company, a Delaware corporation.

       "Borrowing" means an A Borrowing or a B Borrowing.

       "Business Day" means a day of the year on which banks are not required
or authorized to close in Dallas, Texas or New York City and, if the applicable
Business Day relates to any Eurodollar Rate Advances, on which dealings are
carried on in the London interbank market.

       "Capitalization" means for any Person the sum of Consolidated Debt of
such Person plus the Consolidated Tangible Net Worth of such Person.

       "Co-Agent" means either CIBC Inc. or Texas Commerce Bank National
Association in its capacity as co-agent pursuant to Article IX hereof, and "Co-
Agents" means such banks collectively.

       "Code" means, as appropriate, the Internal Revenue Code of 1986, as
amended, or any successor Federal tax code, and any reference to any statutory
provision shall be deemed to be a reference to any successor provision or
provisions.

       "Commitment" of any Bank means at any time the amount set forth as the
"Commitment" of such Bank on the signature pages of this Agreement, or if such
Bank has executed an Assignment or a Consent to Increase of Commitment, then
the amount set forth as the "Commitment" of such Bank therein, or if such Bank
is a New Bank, then the amount set forth as the "Commitment" of such Bank in
the Accession Agreement executed by such Bank, in each case as such amount may
be terminated or reduced pursuant to Section 2.04 or Section 8.01.

       "Consolidated" refers to the consolidation of the accounts of any Person
and its subsidiaries in accordance with generally accepted accounting
principles.

       "Credit Documents" means this Agreement, the Notes, and each other
agreement, instrument or document executed by the Borrower or the Guarantor at
any time in connection with this Agreement.

       "Debt" means, in the case of any Person,  (i) indebtedness of such
Person for borrowed money, (ii) obligations of such Person evidenced by bonds,
debentures, notes or other similar instruments, (iii) obligations of such
Person to pay the deferred purchase price of property or





                                      -4-
<PAGE>   11
services, (iv) obligations of such Person as lessee under leases which are, in
accordance with generally accepted accounting principles, recorded as capital
leases, (v) obligations of such Person in connection with production payments
(except for obligations incurred in connection with Volumetric Production
Payments, stated as either deferred credits or deferred revenues in amounts
outstanding at any time that do not exceed, in the aggregate, 10 percent of
Borrower's Tangible Net Worth), (vi) all liabilities of such Person in respect
of unfunded vested benefits under any Plan, (vii) obligations of such Person
under or relating to letters of credit or guaranties in respect of, and
obligations (contingent or otherwise) to purchase or otherwise acquire, or
otherwise to assure a creditor against loss in respect of, indebtedness or
obligations of others of the kinds referred to in clauses (i) through (vi) of
this definition, and (viii) indebtedness or obligations of others of the kinds
referred to in clauses (i) through (vii) of this definition secured by any Lien
on or in respect of any property of such Person (limited, however, to the
lesser of the amount of its liability or the value of such property).

       "Default" means an Event of Default or an event which, with the giving
of notice or lapse of time or both, would constitute an Event of Default.

       "Domestic Lending Office" means, with respect to any Bank, the office of
such Bank specified as its "Domestic Lending Office" opposite its name on
Schedule I hereto or in an Assignment or such other office of such Bank as such
Bank may from time to time specify to the Borrower and the Agent.

       "Effective Date" means the date that all of the conditions in Section
3.01 shall have been satisfied or waived.

       "Eligible Assignee" means (i) a Bank or (ii) a commercial bank or
financial institution or other Person acceptable to the Agent and the Borrower,
such acceptance not to be unreasonably withheld.

       "Environment" or "Environmental" shall have the meanings set forth in 42
U.S.C. Section 9601(8) (1982).

       "Environmental Protection Statute" shall mean any United States local,
state or federal, or any foreign, law, statute, regulation, order, consent
decree or other agreement or Governmental Requirement arising from or in
connection with or relating to the protection or regulation of the Environment,
including, without limitation, those laws, statutes, regulations, orders,
decrees, agreements and other Governmental Requirements relating to the
disposal, cleanup, production, storing, refining, handling, transferring,
processing or transporting of Hazardous Waste, Hazardous Substances or any
pollutant or contaminant, wherever located.

       "ERISA" means the Employee Retirement Income Security Act of 1974, as
amended from time to time, and the regulations promulgated and rulings issued
thereunder from time to time.





                                      -5-
<PAGE>   12
       "ERISA Affiliate" of the Guarantor means any trade or business (whether
or not incorporated) which is a member of a group of which the Guarantor is a
member and which is under common control within the meaning of the regulations
under Section 414 of the Code.

       "Eurocurrency Liabilities" has the meaning assigned to that term in
Regulation D of the Board of Governors of the Federal Reserve System, as in
effect from time to time.

       "Eurodollar Lending Office" means, with respect to any Bank, the office
of such Bank specified as its "Eurodollar Lending Office" opposite its name on
Schedule I hereto or in an Assignment (or, if no such office is specified, its
Domestic Lending Office) or such other office of such Bank as such Bank may
from time to time specify to the Borrower and the Agent.

       "Eurodollar Rate" means, for the Interest Period for each Eurodollar
Rate Advance comprising part of the same A Borrowing, an interest rate per
annum equal to the rate per annum at which deposits in U.S. dollars are offered
by the principal office of each of the Reference Banks in London, England to
prime banks in the London interbank market at 11:00 A.M. (London time) two
Business Days before the first day of such Interest Period in an amount
substantially equal to the amount of the Eurodollar Rate Advance of such
Reference Bank comprising part of such A Borrowing to be outstanding during
such Interest Period and for a period equal to such Interest Period.  The
Eurodollar Rate for the Interest Period for each Eurodollar Rate Advance
comprising part of the same A Borrowing shall be determined by the Agent on the
basis of applicable rates furnished to and received by the Agent from the
Reference Banks two Business Days before the first day of such Interest Period.

       "Eurodollar Rate Advance" means an A Advance which bears interest as
provided in Section 2.06(b).

       "Eurodollar Rate Reserve Percentage" of any Bank for the Interest Period
for any Eurodollar Rate Advance means the reserve percentage applicable during
such Interest Period (or if more than one such percentage shall be so
applicable, the daily average of such percentages for those days in such
Interest Period during which any such percentage shall be so applicable) under
regulations issued from time to time by the Board of Governors of the Federal
Reserve System (or any successor) for determining the maximum reserve
requirement (including, without limitation, any emergency, supplemental or
other marginal reserve requirement) for such Bank with respect to liabilities
or assets consisting of or including Eurocurrency Liabilities having a term
equal to such Interest Period.

       "Events of Default" has the meaning specified in Section 8.01.

       "Federal Funds Rate" means, for any period, a fluctuating interest rate
per annum equal for each day during such period to the weighted average of the
rates on overnight Federal funds transactions with members of the Federal
Reserve System arranged by Federal funds brokers, as published for such day
(or, if such day is not a Business Day, for the next preceding Business Day)





                                      -6-
<PAGE>   13
by the Federal Reserve Bank of New York, or, if such rate is not so published
for any day which is a Business Day, the average of the quotations for such day
on such transactions received by the Agent from three Federal funds brokers of
recognized standing selected by it.

       "Fixed Rate Advance" means (i) any A Advance which is a Eurodollar Rate
Advance and (ii) any B Advance.

       "Governmental Requirements" means all judgments, orders, writs,
injunctions, decrees, awards, laws, ordinances, statutes, regulations, rules,
franchises, permits, certificates, licenses, authorizations and the like and
any other requirements of any government or any commission, board, court,
agency, instrumentality or political subdivision thereof.

       "Guaranteed Obligations" means all obligations of the Borrower to the
Banks hereunder and under the Notes or any other Credit Document to which the
Borrower is a party, whether for principal, interest, fees, expenses,
indemnities or otherwise, and whether now or hereafter existing.

             "Guarantor" means Fina, Inc., a Delaware corporation.

       "Hazardous Substance" shall have the meaning set forth in 42 U.S.C.
Section 9601(14) and shall also include each other substance considered to be a
hazardous substance under any Environmental Protection Statute.

       "Hazardous Waste" shall have the meaning set forth in 42 U.S.C. Section
6903(5) and shall also include each other substance considered to be a
hazardous waste under any Environmental Protection Statute (including, without
limitation 40 C.F.R. Section 261.3).

       "Insufficiency" means, with respect to any Plan, the amount, if any, by
which the present value of the vested benefits under such Plan exceeds the fair
market value of the assets of such Plan allocable to such benefits.

       "Interest Period" means, for each A Advance comprising part of the same
A Borrowing, the period commencing on the date of such A Advance and ending on
the last day of the period selected by the Borrower pursuant to the provisions
below and Section 2.02.  The duration of each such Interest Period shall be (a)
in the case of a Base Rate Advance, the period commencing on the date of such
Advance and ending on the last day of the then current calendar quarter and (b)
in the case of a Eurodollar Rate Advance, one, two, three, or six months, in
each case as the Borrower may select in the applicable Notice of A Borrowing;
provided, however, that:
              (i)    Interest Periods commencing on the same date for A
Advances comprising part of the same A Borrowing shall be of the same duration;

       (ii)   whenever the last day of any Interest Period would otherwise
occur on a day other than a Business Day, the last day of such Interest Period
shall be extended to occur on the next





                                      -7-
<PAGE>   14
succeeding Business Day, provided, in the case of any Interest Period for a
Eurodollar Rate Advance, that if such extension would cause the last day of
such Interest Period to occur in the next following calendar month, the last
day of such Interest Period shall occur on the next preceding Business Day;

       (iii)  any Interest Period which begins on the last Business Day of the
calendar month (or on a day for which there is no numerically corresponding day
in the calendar month at the end of such Interest Period) shall end on the last
Business Day of the calendar month in which it would have ended if there were a
numerically corresponding day in such calendar month; and

       (iv)   the Borrower may not select an Interest Period for any A Advance
made prior to the Termination Date if the last day of such Interest Period
would be later than the Termination Date.

       "Lien" means any mortgage, lien, pledge, charge, deed of trust, security
interest, encumbrance or other type of preferential arrangement to secure or
provide for the payment of any obligation of any Person, whether arising by
contract, operation of law or otherwise (including, without limitation, the
interest of a vendor or lessor under any conditional sale agreement, capital
lease or other title retention agreement).

       "Liquid Investments" means:

       (a)    direct obligations of, or obligations the principal of and
interest on which are unconditionally guaranteed by, the United States;

       (b)    (i) negotiable or nonnegotiable certificates of deposit, time
deposits, or other similar banking arrangements maturing within 180 days from
the date of acquisition thereof ("bank debt securities"), issued by (A) any
Bank or (B) any other bank or trust company which has a combined capital
surplus and undivided profit of not less than $250,000,000 or the dollar
equivalent thereof, if at the time of deposit or purchase, such bank debt
securities are rated not less than "A" (or the then equivalent) by the rating
service of S&P or of Moody's, and (ii) commercial paper issued by (A) any Bank
or (B) any other Person if at the time of purchase such commercial paper is
rated not less than "A-2" (or the then equivalent) by the rating service of S&P
or not less than "P-2" (or the then equivalent) by the rating service of
Moody's, or upon the discontinuance of both of such services, such other
nationally recognized rating service or services, as the case may be, as shall
be selected by the Borrower or the Guarantor with the consent of the Majority
Banks;

       (c)    repurchase agreements relating to investments described in
clauses (a) and (b) above with a market value at least equal to the
consideration paid in connection therewith, with any Person who regularly
engages in the business of entering into repurchase agreements and has a
combined capital surplus and undivided profit of not less than $250,000,000 or
the dollar equivalent thereof, if at the time of entering into such agreement
the debt securities of such Person are rated not less than "A" (or the then
equivalent) by the rating service of S&P or of Moody's;





                                      -8-
<PAGE>   15
       (d)    shares of any mutual fund registered under the Investment Company
Act of 1940, as amended, which invests solely in underlying securities of the
types described in clauses (a), (b) and (c) above and which do not constitute
"margin stock" within the meaning of Regulation U of the Federal Reserve Board;
and

       (e)    such other instruments (within the meaning of Article 9 of the
Texas Business and Commerce Code) as the Borrower or the Guarantor may request
and the Majority Banks may approve in writing, which approval will not be
unreasonably withheld.

       "Majority Banks" means at any time Banks holding at least 51% of the
then aggregate unpaid principal amount of the A Notes held by the Banks, or, if
no such principal amount is then outstanding, Banks having at least 51% of the
Commitments or, if no such principal amount is then outstanding and all
Commitments have terminated, Banks holding at least 51% of the then aggregate
unpaid principal amount of the B Notes held by the Banks.

       "Moody's" means Moody's Investors Service, or any successor thereto.

       "Multiemployer Plan" means a "multiemployer plan" as defined in Section
4001(a)(3) of ERISA to which the Guarantor or any ERISA Affiliate of the
Guarantor is making or accruing an obligation to make contributions, or has
within any of the preceding five plan years made or accrued an obligation to
make contributions.

       "Multiple Employer Plan" means an employee benefit plan, other than a
Multiemployer Plan, subject to Title IV of ERISA to which the Guarantor or any
ERISA Affiliate of the Guarantor, and one or more employers other than the
Guarantor or an ERISA Affiliate of the Guarantor, is making or accruing an
obligation to make contributions or, in the event that any such plan has been
terminated, to which the Guarantor or any ERISA Affiliate of the Guarantor made
or accrued an obligation to make contributions during any of the five plan
years preceding the date of termination of such plan.

       "NationsBank" means NationsBank of Texas, N.A.

       "New Bank" means any lender which becomes a "Bank" hereunder by
executing an  Accession Agreement pursuant to an increase in the aggregate
Commitments permitted by Section 2.15.

       "Note" means an A Note or a B Note.

       "Notice of A Borrowing" has the meaning specified in Section 2.02(a).

       "Notice of B Borrowing" has the meaning specified in Section 2.08(a).





                                      -9-
<PAGE>   16
       "Parallel Agreement" means the U.S. $325,000,000 5-Year Credit Agreement
dated as of February 27, 1997 among the Borrower, the Guarantor, the Agent, the
Arranger & Syndication Agent and the Banks, as amended or modified from time to
time.

       "Parallel Agreement Commitments" means, as of any date of determination,
the "Commitments" as defined in the Parallel Agreement.

       "PBGC" means the Pension Benefit Guaranty Corporation.

       "Permitted Liens" means, with respect to any Person, Liens:

       (a)    for taxes, assessments or governmental charges or levies on
property of such Person incurred in the ordinary course of business to the
extent not required to be paid pursuant to Sections 6.01 and 6.06;

       (b)    imposed by law, such as landlords', carriers', warehousemen's and
mechanics' liens and other similar Liens arising in the ordinary course of
business securing obligations which are not overdue for a period of more than
15 days or which are being contested in good faith and by appropriate
proceedings if adequate reserves with respect thereto are maintained on the
books of such Person in accordance with generally accepted accounting
principles;

       (c)    arising in the ordinary course of business out of pledges or
deposits under workers' compensation laws, unemployment insurance, old age
pensions or other social security or retirement benefits, or similar
legislation or to secure public or statutory obligations of such Person;

       (d)    securing Debt existing on the date of this Agreement and listed
on the attached Schedule III; provided that the Debt secured by such Liens
shall not be renewed, refinanced or extended if the amount of such Debt so
renewed is greater than the outstanding amount of such Debt on the date of this
Agreement;

       (e)    constituting easements, rights-of-way, restrictions and other
similar encumbrances incurred in the ordinary course of business and
encumbrances consisting of zoning restrictions, easements, licenses,
restrictions on the use of property or minor imperfections in title thereto
which, in the aggregate, are not material in amount, and which do not in any
case materially detract from the value of the property subject thereto or
materially interfere with the ordinary conduct of the business of such Person;

       (f)    securing judgments against such Person which are being appealed
and do not constitute an Event of Default under Section 8.01(f); or

       (g)    on real property acquired by such Person after the date of this
Agreement and securing only Debt of such Person incurred to finance the
purchase price of such property; provided that any such Lien is created within
180 days of the acquisition of such property and provided further





                                      -10-
<PAGE>   17
that the Debt secured by all such Liens does not exceed 35% of Consolidated
Tangible Net Worth of the Guarantor and the Restricted Subsidiaries.

       "Person" means an individual, partnership, corporation, limited
liability company, limited liability partnership, business trust, joint stock
company, trust, unincorporated association, joint venture or other entity, or a
government or any political subdivision or agency thereof.

       "Plan" means an employee pension benefit plan (other than a
Multiemployer Plan) as defined in Section 3(2) of ERISA currently maintained
by, or to which contributions have been made at any time after December 31,
1984 by, the Guarantor or any ERISA Affiliate of the Guarantor for employees of
the Guarantor or any such ERISA Affiliate and covered by Title IV of ERISA or
subject to the minimum funding standards under Section 412 of the Code.

       "Reference Banks" means NationsBank, CIBC Inc. and Texas Commerce Bank
National Association.

       "Restricted Payment" means, with respect to any Person, (i) any dividend
paid on its capital stock, (ii) any repurchase of its capital stock, or (iii)
any loan or advance or payment of any kind with respect to its capital stock.

       "Restricted Subsidiary" means the Borrower or any other Subsidiary of
the Guarantor which (i) is organized under the laws of the United States or any
state thereof and (ii) has assets with an aggregate book value exceeding
$10,000,000.

       "Revolving Period" means the period of time commencing on the
effectiveness of this Agreement and ending on the Termination Date.

       "S&P" means Standard & Poor's Ratings Services, a division of The
McGraw-Hill Companies, Inc., or any successor thereto.

       "Subsidiary" of any Person means any corporation of which more than 50%
of the outstanding capital stock having ordinary voting power to elect a
majority of the board of directors of such corporation or others performing
similar functions (irrespective of whether or not at the time capital stock of
any other class or classes of such corporation shall or might have voting power
upon the occurrence of any contingency) is at the time directly or indirectly
owned by such Person.

       "Substantial Part" means, with respect to the assets of the Guarantor
and the Restricted Subsidiaries, assets which in the aggregate in any one
fiscal year of the Guarantor exceed 10% of the Consolidated Tangible Net Worth
of the Guarantor and its Subsidiaries.

       "Tangible Net Worth" of any Person means, as of any date of
determination, the excess of total assets of such Person over total
liabilities, total assets and total liabilities each to be determined in
accordance with generally accepted accounting principles, excluding, however,
from the





                                      -11-
<PAGE>   18
determination of total assets (i) patents, patent applications, trademarks,
copyrights and trade names, (ii) goodwill, organizational, experimental,
research and development expense and other like intangibles, (iii) treasury
stock, and (iv) monies set apart and held in a sinking or other analogous fund
established for the purchase, redemption or other retirement of capital stock.

       "Termination Date" means February 26, 1998, or the earlier date of
termination in whole of the Commitments pursuant to Section 2.04 or 8.01.

       "Termination Event" means (i) a "reportable event", as such term is
described in Section 4043 of ERISA (other than a "reportable event" not subject
to the provision for 30-day notice to the PBGC), or an event described in
Section 4062(f) of ERISA, or (ii) the withdrawal of the Guarantor or any ERISA
Affiliate of the Guarantor from a Multiple Employer Plan during a plan year in
which it was a "substantial employer", as such term is defined in Section
4001(a)(2) of ERISA, or the incurrence of liability by the Guarantor or any
ERISA Affiliate of the Guarantor under Section 4064 of ERISA upon the
termination of a Plan or Multiple Employer Plan, or (iii) the distribution of a
notice of intent to terminate a Plan pursuant to Section 4041(a)(2) of ERISA or
the treatment of a Plan amendment as a termination under Section 4041 of ERISA,
or (iv) the institution of proceedings to terminate a Plan by the PBGC under
Section 4042 of ERISA, or (v) any other event or condition which might
constitute grounds under Section 4042 of ERISA for the termination of, or the
appointment of a trustee to administer, any Plan.

       "Type" shall have the meaning set forth in the definition of the term "A
Advance" above.

       "Volumetric Production Payment" means, with respect to any Person, any
obligation of such Person to deliver pre-determined volumes of oil or gas out
of future production from designated reserves that is without recourse to other
assets of such Person.

       "Withdrawal Liability" shall have the meaning given such term under Part
I of Subtitle E of Title IV of ERISA.

       Section 1.02.  Computation of Time Periods.  In this Agreement in the
computation of periods of time from a specified date to a later specified date,
the word "from" means "from and including" and the words "to" and "until" each
means "to but excluding."

       Section 1.03.  Accounting Terms.  All accounting terms not specifically
defined herein shall be construed in accordance with generally accepted
accounting principles, and each reference herein to "generally accepted
accounting principles" shall mean generally accepted accounting principles
consistent with those applied in the preparation of the financial statements
referred to in Section 5.05.

       Section 1.04.  Miscellaneous.  The words "hereof", "herein" and
"hereunder" and words of similar import when used in this Agreement shall refer
to this Agreement as a whole and not to any





                                      -12-
<PAGE>   19
particular provision of this Agreement, and Article, Section, Schedule and
Exhibit references are to Articles and Sections of and Schedules and Exhibits
to this Agreement, unless otherwise specified.


                                   ARTICLE II

                       AMOUNTS AND TERMS OF THE ADVANCES

       Section 2.01.  The A Advances.  Each Bank severally agrees, on the terms
and conditions hereinafter set forth, to make A Advances to the Borrower from
time to time on any Business Day prior to the Termination Date in an aggregate
amount outstanding not to exceed at any time such Bank's Commitment, provided
that the aggregate amount of the Commitments of the Banks shall be deemed used
from time to time to the extent of the aggregate amount of the B Advances then
outstanding and such deemed use of the aggregate amount of the Commitments
shall be applied to the Banks ratably according to their respective Commitments
(such deemed use of the aggregate amount of the Commitments being a "B
Reduction").  Each A Borrowing shall be in an aggregate amount not less than
$5,000,000 or an integral multiple of $1,000,000 in excess thereof, and shall
consist of A Advances of the same Type made to the Borrower on the same day by
the Banks ratably according to their respective Commitments.  Within the limits
of each Bank's Commitment, the Borrower may borrow, prepay pursuant to Section
2.05(b) and reborrow under this Section 2.01. The indebtedness of the Borrower
resulting from the A Advances made from time to time by each Bank shall be
evidenced by an A Note of the Borrower payable to the order of such Bank.

       Section 2.02.  Making the A Advances.

       (a)    During the Revolving Period, each A Borrowing shall be made on
notice, given not later than 10:00 A.M. (Dallas time) (1) in the case of a
proposed Borrowing comprised of Eurodollar Rate Advances, at least three
Business Days prior to the date of the proposed Borrowing, and (2) in the case
of a proposed Borrowing comprised of Base Rate Advances, on the Business Day of
the proposed Borrowing, by the Borrower requesting such A Borrowing to the
Agent, which shall give to each Bank prompt notice thereof by telecopy, telex
or cable.  Each such notice of an A Borrowing (a "Notice of A Borrowing") shall
be in writing (including by telecopy), in substantially the form of Exhibit B-1
hereto, executed by the Borrower and specifying therein the requested (i) date
of such A Borrowing (which shall be a Business Day), (ii) Type of A Advances
comprising such A Borrowing, (iii) aggregate amount of such A Borrowing, and
(iv) Interest Period for each such A Advance.  In the case of a proposed A
Borrowing comprised of Eurodollar Rate Advances, the Agent shall promptly
notify each Bank of the applicable interest rate under Section 2.06(b).  Each
Bank shall, before 1:00 P.M. (Dallas time) on the date of a proposed A
Borrowing, make available for the account of its Applicable Lending Office to
the Agent at its address referred to in Section 10.02, in same day funds, such
Bank's ratable portion of such A Borrowing.  After the Agent's receipt of such
funds and upon fulfillment of the applicable conditions set forth in Article
III, the Agent will make such funds available to the Borrower at the Agent's
aforesaid address.





                                      -13-
<PAGE>   20
       (b)    Anything in subsection (a) above to the contrary notwithstanding:

       (i)    at no time shall there be outstanding more than five A Borrowings
              consisting of Eurodollar Rate Advances and one Borrowing
              consisting of Base Rate Advances (other than Borrowings
              consisting of Base Rate Advances as a result of Section
              2.02(b)(iii), (iv), or (v));

       (ii)   the Borrower may not select Eurodollar Rate Advances for any A
              Borrowing to be made if the aggregate amount of such Borrowing is
              less than $20,000,000;

       (iii)  if any Bank shall, at least one Business Day before the date of
              any requested A Borrowing to be made, notify the Agent that the
              introduction of or any change in or in the interpretation of any
              law or regulation makes it unlawful, or that any central bank or
              other governmental authority asserts that it is unlawful, for
              such Bank or its Eurodollar Lending Office to perform its
              obligations hereunder to make Eurodollar Rate Advances or to fund
              Eurodollar Rate Advances hereunder, the right of the Borrower to
              select Eurodollar Rate Advances for such A Borrowing or any
              subsequent A Borrowing shall be suspended until such Bank shall
              notify the Agent that the circumstances causing such suspension
              no longer exist, and, except as provided in Section 2.02(b)(vi),
              each Advance comprising such A Borrowing shall be a Base Rate
              Advance;

       (iv)   if the Majority Banks shall, on or before the date of any
              requested A Borrowing to be made, notify the Agent that the
              Eurodollar Rate for Eurodollar Rate Advances comprising such A
              Borrowing will not adequately reflect the cost to such Banks of
              making their respective Eurodollar Rate Advances for such A
              Borrowing, the right of the Borrower to select Eurodollar Rate
              Advances for such A Borrowing or any subsequent A Borrowing shall
              be suspended until the Agent, at the request of the Majority
              Banks, shall notify the Borrower and the Banks that the
              circumstances causing such suspension no longer exist, and,
              except as provided in Section 2.02(b)(vi), each Advance
              comprising such A Borrowing shall be a Base Rate Advance;

       (v)    if less than two Reference Banks furnish timely information to
              the Agent for determining the Eurodollar Rate for Eurodollar Rate
              Advances, comprising any requested A Borrowing to be made, the
              right of the Borrower to select Eurodollar Rate Advances, as the
              case may be, for such A Borrowing or any subsequent A Borrowing
              shall be suspended until the Agent shall notify the Borrower and
              the Banks that the circumstances causing such suspension no
              longer exist, and, except as provided in Section 2.02(b)(vi),
              each Advance comprising such A Borrowing shall be a Base Rate
              Advance;





                                      -14-
<PAGE>   21
        (vi)  if the Borrower has requested a proposed A Borrowing consisting
              of Eurodollar Rate Advances and as a result of circumstances
              referred to in Section 2.02(b)(iii), (iv) or (v) such A Borrowing
              would not consist of Eurodollar Rate Advances, the Borrower may,
              by notice given not later than 2:00 P.M. (Dallas time) at least
              one Business Day prior to the date such proposed A Borrowing
              would otherwise be made, cancel such A Borrowing, in which case
              such A Borrowing shall be cancelled and no Advances shall be made
              as a result of such requested A Borrowing, but the Borrower shall
              indemnify the Banks in connection with such cancellation as
              contemplated by Section 2.02(c); and

       (vii)  if the Borrower shall fail to select the duration or continuation
              of any Interest Period for any Eurodollar Rate Advances in
              accordance with the provisions contained in the definition of
              "Interest Period" in Section 1.01 and this paragraph (b), the
              Agent will promptly so notify the Borrower and the Banks and such
              A Advances will be made available to the Borrower on the date of
              such A Borrowing as Base Rate Advances.

       (c)    Each Notice of A Borrowing shall be irrevocable and binding on
the Borrower, except as set forth in Section 2.02(b)(vi).  In the case of any A
Borrowing requested by the Borrower which the related Notice of A Borrowing
specifies is to be comprised of Eurodollar Rate Advances, the Borrower shall
indemnify each Bank against any loss, cost or expense incurred by such Bank as
a result of any failure to fulfill on or before the date specified in such
Notice of A Borrowing for such A Borrowing the applicable conditions set forth
in Article III, including, without limitation, any loss (including loss of
reasonably anticipated profits), cost or expense incurred by reason of the
liquidation or reemployment of deposits or other funds acquired by such Bank to
fund the A Advance to be made by such Bank as part of such A Borrowing when
such A Advance, as a result of such failure, is not made on such date.  A
certificate in reasonable detail as to the basis for and the amount of such
loss, cost or expense submitted to the Borrower and the Agent by such Bank
shall be prima facie evidence of the amount of such loss, cost or expense.  If
an A Borrowing requested by the Borrower which the related Notice of A
Borrowing specifies is to be comprised of Eurodollar Rate Advances is not made
as an A Borrowing comprised of Eurodollar Rate Advances as a result of Section
2.02(b), the Borrower shall indemnify each Bank against any loss (excluding
loss of profits), cost or expense incurred by such Bank by reason of the
liquidation or reemployment of deposits or other funds acquired by such Bank
(prior to the time such Bank is actually aware that such A Borrowing will not
be so made) to fund the A Advance to be made by such Bank as part of such A
Borrowing.  A certificate in reasonable detail as to the basis for and the
amount of such loss, cost or expense submitted to the Borrower and the Agent by
such Bank shall be prima facie evidence of the amount of such loss, cost or
expense.

       (d)    With respect to any new A Borrowing to be made on the last day of
an Interest Period, the Borrower and each Bank agree that any amounts payable
by the Borrower to such Bank in connection with maturing A Advances on the date
of such Borrowing shall be netted against the amount of the new Borrowing to be
funded by such Bank so as to eliminate where possible the need for actual
payment and readvancement of funds by the parties.  In the event of any A
Borrowing





                                      -15-
<PAGE>   22
subject to the conditions precedent in Section 3.03, unless the Agent shall
have received notice from a Bank prior to the date of such A Borrowing that
such Bank will not make available to the Agent such Bank's ratable portion of
such A Borrowing (to the extent in excess of any maturing A Advances payable to
such Bank), the Agent may assume that such Bank has made such portion available
to the Agent on the date of such A Borrowing in accordance with subsection (a)
of this Section 2.02 and the Agent may, in reliance upon such assumption, make
available to the Borrower on such date a corresponding amount.  If and to the
extent that such Bank shall not have so made such ratable portion available to
the Agent, such Bank and the Borrower severally agree to repay to the Agent
forthwith on demand such corresponding amount together with interest thereon,
for each day from the date such amount is made available to the Borrower until
the date such amount is repaid to the Agent, at (i) in the case of the
Borrower, the interest rate applicable at the time to A Advances comprising
such A Borrowing and (ii) in the case of such Bank, the Federal Funds Rate.  If
such Bank shall repay to the Agent such corresponding amount, such amount so
repaid shall constitute such Bank's A Advance as part of such A Borrowing for
purposes of this Agreement.

       (e)    The failure of any Bank to make the A Advance to be made by it as
part of any A Borrowing shall not relieve any other Bank of its obligation, if
any, hereunder to make its A Advance on the date of such A Borrowing, but no
Bank shall be responsible for the failure of any other Bank to make the A
Advance to be made by such other Bank on the date of any A Borrowing.

       Section 2.03.  Fees.

       (a)    Facility Fee.  The Borrower agrees to pay to each Bank a facility
fee calculated on the amount of such Bank's Commitment (regardless of usage)
from the date hereof until the Termination Date at the Applicable Facility Fee
per annum, payable in arrears on the last day of each calendar quarter during
the term of such Bank's Commitment, and on the Termination Date.

       (b)    Administrative Fee.  The Borrower agrees to pay to the Agent, for
its sole account, an administrative fee as set forth in the Agent's Fee Letter.

       (c)    Bid Request Fee.  The Borrower agrees to pay to the Agent on the
date of each request for B Advances pursuant to Section 2.08 a bid request fee
as set forth in the Agent's Fee Letter.

       (d)    Arrangement Fee.  The Borrower agrees to pay to the Agent on the
date of this Agreement an arrangement fee as set forth in the Agent's Fee
Letter.

       Section 2.04.  Optional Reduction of the Commitments.  The Borrower
shall have the right, upon at least five Business Days notice to the Agent, to
terminate in whole or reduce ratably in part the unused portions of the
respective Commitments of the Banks, provided that each partial reduction shall
be in the aggregate amount of at least $10,000,000, and provided further, that
the aggregate amount of the Commitments of the Banks shall not be reduced to an
amount which is less





                                      -16-
<PAGE>   23
than the aggregate principal amount of the Advances then outstanding.  Any such
reduction or termination of the Commitments shall be permanent.

       Section 2.05.  Repayment and Prepayment of A Advances.  (a) The unpaid
principal amount of each A Advance that is made by each Bank shall be repaid by
the Borrower in full on the last day of the Interest Period for such A Advance.


       (b)    The Borrower may, in respect of Base Rate Advances upon at least
one Business Days' notice, and, in respect of Eurodollar Rate Advances upon at
least three Business Days' notice, to the Agent stating the proposed date
(which shall be a Business Day) and aggregate principal amount of the
prepayment, and if such notice is given the Borrower shall, prepay the
outstanding principal amounts of the A Advances comprising part of the same A
Borrowing in whole or ratably in part, together with accrued interest to the
date of such prepayment on the principal amount prepaid and amounts, if any,
required to be paid pursuant to Section 2.10 as a result of such prepayment;
provided, however, that each partial prepayment pursuant to this Section
2.05(b) shall be in an aggregate principal amount not less than $5,000,000 and
in an aggregate principal amount such that after giving effect thereto no A
Borrowing comprised of Base Rate Advances shall have a principal amount
outstanding of less than $5,000,000 and no A Borrowing comprised of Eurodollar
Rate Advances shall have a principal amount outstanding of less than
$20,000,000.

       Section 2.06.  Interest on A Advances.  The Borrower shall pay interest
on the unpaid principal amount of each A Advance made by each Bank from the
date of such A Advance until such principal amount shall be paid in full, at
the following rates per annum:

       (a)    Base Rate Advances.  If such A Advance is a Base Rate Advance, a
rate per annum equal at all times during the Interest Period for such A Advance
to the Base Rate in effect from time to time during such Interest Period for
such A Advance, payable on the last day of such Interest Period.

       (b)    Eurodollar Rate Advances.  If such A Advance is a Eurodollar Rate
Advance, a rate per annum equal at all times during the Interest Period for
such A Advance to the sum of the Eurodollar Rate for such Interest Period plus
the Applicable Margin in effect from time to time for such A Advance, payable
on the last day of such Interest Period and, if such Interest Period has a
duration of more than three months, on each day which occurs during such
Interest Period every three months from the first day of such Interest Period.

       (c)    Additional Interest on Eurodollar Rate Advances.  The Borrower
shall pay to each Bank, so long as such Bank shall be required under
regulations of the Board of Governors of the Federal Reserve System to maintain
reserves with respect to liabilities or assets consisting of or including
Eurocurrency Liabilities, additional interest on the unpaid principal amount of
each Eurodollar Rate Advance of such Bank, from the date of such Advance until
such principal amount is paid in full, at an interest rate per annum equal at
all times to the remainder obtained by subtracting (i) the Eurodollar Rate for
the Interest Period for such Advance from (ii) the rate obtained





                                      -17-
<PAGE>   24
by dividing such Eurodollar Rate by a percentage equal to 100% minus the
Eurodollar Rate Reserve Percentage of such Bank for such Interest Period,
payable on each date on which interest is payable on such Advance.  Such
additional interest shall be determined by such Bank and notified to the
Borrower through the Agent.  A certificate as to the amount of such additional
interest submitted to the Borrower and the Agent by such Bank shall be
conclusive and binding for all purposes, absent manifest error.

       Section 2.07.  Interest Rate Determination.  (a) Each Reference Bank
agrees to furnish to the Agent timely information for the purpose of
determining each Eurodollar Rate.  If any of the Reference Banks shall not
furnish such timely information to the Agent for the purpose of determining any
such Eurodollar Rate, the Agent shall determine such Eurodollar Rate on the
basis of timely information furnished by the remaining Reference Banks, subject
to Section 2.02(b).

       (b)    The Agent shall give prompt notice to the Borrower and the Banks
of the applicable interest rate for such A Advance determined by the Agent for
purposes of Section 2.06(a) or (b), and the applicable rate, if any, furnished
by each Reference Bank for the purpose of determining the applicable interest
rate under Section 2.06(b).

       Section 2.08.  The B Advances.

       (a) Each Bank severally agrees that the Borrower may make B Borrowings
under this Section 2.08 from time to time on any Business Day during the period
from the date hereof until the date occurring 30 days prior to the Termination
Date in the manner set forth below; provided that, following the making of each
B Borrowing, the aggregate amount of the Advances then outstanding shall not
exceed the aggregate amount of the Commitments of the Banks (computed without
regard to any B Reduction).

       (i)    The Borrower may request a B Borrowing under this Section 2.08 by
              delivering to the Agent, not later than 9:00 A.M. (Dallas time)
              at least five Business Days prior to the date of the proposed B
              Borrowing, a notice of a B Borrowing (a "Notice of B Borrowing"),
              in substantially the form of Exhibit B-2 hereto, specifying the
              date and aggregate amount of the proposed B Borrowing, the
              maturity date for repayment of each B Advance to be made as part
              of such B Borrowing (which maturity date may not be earlier than
              the date occurring 14 days after the date of such B Borrowing or
              later than the earlier of 6 months after the date of such B
              Borrowing or the Termination Date), the interest payment date or
              dates relating thereto, and any other terms to be applicable to
              such B Borrowing (including, without limitation, the basis to be
              used by the Banks in determining the rate or rates of interest to
              be offered by them as provided in paragraph (ii) below and
              prepayment terms, if any, but excluding any waiver or other
              modification to any of the conditions set forth in Article III).
              The Borrower may not select a maturity date for any B Borrowing
              which ends after the Termination Date.  The Agent shall promptly
              notify each Bank of each request





                                      -18-
<PAGE>   25
              for a B Borrowing received by it from the Borrower by sending
              such Bank a copy of the related Notice of B Borrowing.

       (ii)   Each Bank may, if in its sole discretion it elects to do so,
              irrevocably offer to make one or more B Advances to the Borrower
              as part of such proposed B Borrowing at a rate or rates of
              interest specified by such Bank in its sole discretion, by
              notifying the Agent (which shall give prompt notice thereof to
              the Borrower), before 9:00 A.M. (Dallas time) three Business Days
              before the date of such proposed B Borrowing specified in the
              Notice of B Borrowing delivered with respect thereto pursuant to
              paragraph (i) above, of the minimum amount and maximum amount of
              each B Advance which such Bank would be willing to make as part
              of such proposed B Borrowing (which amounts may, subject to the
              proviso to the first sentence of this Section 2.08(a), exceed
              such Bank's Commitment), the rate or rates of interest therefor
              and such Bank's Applicable Lending Office with respect to such B
              Advance; provided that if the Agent in its capacity as a Bank
              shall, in its sole discretion, elect to make any such offer, it
              shall notify the Borrower of such offer before 8:45 A.M. (Dallas
              time) three Business Days before the date of the proposed B
              Borrowing specified in the Notice of B Borrowing delivered with
              respect thereto pursuant to paragraph (i) above.  Any Bank which
              has not notified the Agent of an offer prior to the time
              specified above shall be deemed to have elected not to make such
              an offer.

       (iii)  The Borrower shall, in turn, before 10:00 A.M. (Dallas time)
              three Business Days before the date of such proposed B Borrowing
              specified in the Notice of B Borrowing delivered with respect
              thereto pursuant to paragraph (i) above, either

                     (A)    cancel such B Borrowing by giving the Agent notice
              to that effect, or

                     (B)    accept one or more of the offers made by any Bank
              or Banks pursuant to paragraph (ii) above, in its sole
              discretion, by giving notice to the Agent of the amount of each B
              Advance (which amount shall be equal to or greater than the
              minimum amount, and equal to or less than the maximum amount,
              notified to the Borrower by the Agent on behalf of such Bank for
              such B Advance pursuant to paragraph (ii) above) to be made by
              each Bank as part of such B Borrowing, and reject any remaining
              offers made by Banks pursuant to paragraph (ii) above by giving
              the Agent notice to that effect.

       (iv)   If the Borrower notifies the Agent that such B Borrowing is
              cancelled pursuant to paragraph (iii)(A) above, the Agent shall
              give prompt notice thereof to the Banks and such B Borrowing
              shall not be made.

       (v)    If the Borrower accepts one or more of the offers made by any
              Bank or Banks pursuant to paragraph (iii)(B) above, the Agent
              shall in turn promptly notify (A) each Bank that has made an
              offer as described in paragraph (ii) above, of the date and





                                      -19-
<PAGE>   26
              aggregate amount of such B Borrowing and whether or not any offer
              or offers made by such Bank pursuant to paragraph (ii) above have
              been accepted by the Borrower, (B) each Bank that is to make a B
              Advance as part of such B Borrowing, of the amount of each B
              Advance to be made by such Bank as part of such B Borrowing, and
              (C) each Bank that is to make a B Advance as part of such B
              Borrowing, upon receipt, that the Agent has received forms of
              documents appearing to fulfill the applicable conditions set
              forth in Article III.  Each Bank that is to make a B Advance as
              part of such B Borrowing shall, before 1:00 P.M. (Dallas time) on
              the date of such B Borrowing specified in the notice received
              from the Agent pursuant to clause (A) of the preceding sentence
              or any later time when such Bank shall have received notice from
              the Agent pursuant to clause (C) of the preceding sentence, make
              available for the account of its Applicable Lending Office to the
              Agent at its address referred to in Section 10.02 such Bank's
              portion of such B Borrowing, in same day funds.  Upon fulfillment
              of the applicable conditions set forth in Article III and after
              receipt by the Agent of such funds, the Agent will make such
              funds available to the Borrower at the Agent's aforesaid address.
              Promptly after each B Borrowing the Agent will notify each Bank
              of the amount of the B Borrowing, the consequent B Reduction and
              the dates upon which such B Reduction commenced and will
              terminate.

       (b)    Each B Borrowing shall be in an aggregate amount of not less than
$5,000,000 or an integral multiple of $1,000,000 in excess thereof and,
following the making of each B Borrowing, the Borrower shall be in compliance
with the limitation set forth in the proviso to the first sentence of Section
2.08(a).

       (c)    Within the limits and on the conditions set forth in this Section
2.08, the Borrower may from time to time borrow under this Section 2.08, repay
pursuant to subsection (d) below, and reborrow under this Section 2.08,
provided that no B Borrowing shall be made within three Business Days of the
date of another B Borrowing.

       (d)    The Borrower shall repay to the Agent for the account of each
Bank which has made a B Advance to the Borrower on the maturity date of each B
Advance (such maturity date being that specified by the Borrower for repayment
of such B Advance in the related Notice of B Borrowing delivered pursuant to
subsection (a)(i) above) the then unpaid principal amount of such B Advance.
The Borrower shall not have any right to prepay any principal amount of any B
Advance unless, and then only on the terms, specified by the Borrower for such
B Advance in the related Notice of B Borrowing delivered pursuant to subsection
(a)(i) above and set forth in the B Note evidencing such B Advance.

       (e)    The Borrower shall pay interest on the unpaid principal amount of
each B Advance from the date of such B Advance to the date the principal amount
of such B Advance is repaid in full, at the rate of interest for such B Advance
specified by the Bank making such B Advance in its notice with respect thereto
delivered pursuant to subsection (a)(ii) above, payable on the interest





                                      -20-
<PAGE>   27
payment date or dates specified by the Borrower for such B Advance in the
related Notice of B Borrowing delivered pursuant to subsection (a)(i) above, as
provided in the B Note evidencing such B Advance.

       (f)    The indebtedness of the Borrower resulting from each B Advance
made to the Borrower as part of a B Borrowing shall be evidenced by a separate
B Note of the Borrower payable to the order of the Bank making such B Advance.

       Section 2.09.  Payments, Computations; Interest on Overdue Amounts.

       (a) The Borrower shall make each payment hereunder and under the Notes
to be made by it not later than 10:00 A.M. (Dallas time) on the day when due in
U.S. dollars to the Agent at its address referred to in Section 10.02 in same
day funds.  The Agent will promptly thereafter cause to be distributed like
funds relating to the payment of principal, interest or fees ratably (other
than amounts payable pursuant to Section 2.06(c), 2.08, 2.10, 2.11 or 2.13) to
the Banks for the account of their respective Applicable Lending Offices, and
like funds relating to the payment of any other amount payable to any Bank to
such Bank for the account of its Applicable Lending Office, in each case to be
applied in accordance with the terms of this Agreement.  In no event shall any
Bank be entitled to share any administrative fee paid to the Agent pursuant to
Section 2.03(b), any bid request fee paid to the Agent pursuant to Section
2.03(c) or any other fee paid to the Agent, as such.

       (b)    All computations of interest based on the Base Rate and of fees
shall be made by the Agent on the basis of a year of 365 or 366 days, as the
case may be, and all computations of interest based on the Eurodollar Rate or
the Federal Funds Rate shall be made by the Agent, and all computations of
interest pursuant to Section 2.06(c) shall be made by a Bank, on the basis of a
year of 360 days, in each case for the actual number of days (including the
first day but excluding the last day) occurring in the period for which such
interest or fees are payable.  Each determination by the Agent (or, in the case
of Section 2.06(c), by a Bank) of an interest rate hereunder shall be
conclusive and binding for all purposes, absent manifest error.

       (c)    Whenever any payment hereunder or under the Notes shall be stated
to be due on a day other than a Business Day, such payment shall be made on the
next succeeding Business Day, and such extension of time shall in such case be
included in the computation of payment of interest or fee, as the case may be;
provided, however, if such extension would cause payment of interest on or
principal of Eurodollar Rate Advances to be made in the next following calendar
month, such payment shall be made on the next preceding Business Day.

       (d)    Unless the Agent shall have received notice from the Borrower
prior to the date on which any payment is due by the Borrower to any Bank
hereunder that the Borrower will not make such payment in full, the Agent may
assume that the Borrower has made such payment in full to the Agent on such
date and the Agent may, in reliance upon such assumption, cause to be
distributed to each Bank on such due date an amount equal to the amount then
due such Bank.  If and to the extent the Borrower shall not have so made such
payment in full to the Agent, each Bank shall repay





                                      -21-
<PAGE>   28
to the Agent forthwith on demand such amount distributed to such Bank together
with interest thereon, for each day from the date such amount is distributed to
such Bank until the date such Bank repays such amount to the Agent, at the
Federal Funds Rate.

       (e)    Whenever any reference is made to any Bank's "ratable share" or
"ratable portion" (or any similar reference) of any amount hereunder, such
share or portion shall be calculated to not more than four decimal places,
rounding up or down, as appropriate.

       (f)    Any amount payable hereunder or under the Notes or under any
other Credit Document which is not paid when due (whether at stated maturity,
by acceleration or otherwise) shall bear interest, to the extent permitted by
law, from the date on which such amount became due until such amount is paid in
full, payable on demand, at a rate per annum equal at all times to:  (i) in the
case of any overdue principal of any Advance, the greater of (x) the sum of the
Base Rate in effect from time to time plus 2% per annum and (y) the sum of the
rate per annum required to be paid on such Advance immediately prior to the
date on which such amount became due plus 2% per annum, or (ii) in the case of
any interest, fee or other amount payable hereunder or under the Notes or under
any other Credit Document, the sum of the Base Rate in effect from time to time
plus 2% per annum.

       Section 2.10.  Consequential Losses.  If (a) any payment (or purchase
pursuant to Section 2.11(c)) of principal of any Eurodollar Rate Advance or B
Advance made to the Borrower is made other than on the last day of an Interest
Period relating to such Advance (or in the case of a B Advance, other than on
the original scheduled maturity date thereof), as a result of a prepayment
pursuant to Section 2.05(b) or 2.12 or acceleration of the maturity of the
Notes pursuant to Section 2.15 or Section 8.01 or for any other reason or as a
result of any such purchase; or (b) the Borrower fails to make a principal or
interest payment with respect to any Eurodollar Rate Advance or B Advance on
the date such payment is due and payable, the Borrower shall, upon demand by
any Bank (with a copy of such demand to the Agent), pay to the Agent for the
account of such Bank any amounts required to compensate such Bank for any
additional losses, costs or expenses which it may reasonably incur as a result
of any such payment or purchase, including, without limitation, any loss
(including loss of reasonably anticipated profits, except in the case of such a
purchase pursuant to Section 2.11(c)), cost or expense incurred by reason of
the liquidation or reemployment of deposits or other funds acquired by such
Bank to fund or maintain such Advance.

       Section 2.11.  Increased Costs.

       (a) If, due to either (i) the introduction of or any change (including
without limitation, but without duplication, any change by way of imposition or
increase of reserve requirements included, in the case of Eurodollar Rate
Advances, the Eurodollar Rate Reserve Percentage) in or in the interpretation,
application or applicability of any law or regulation or (ii) the compliance
with any guideline or request from any central bank or other governmental
authority (whether or not having the force of law), there shall be any increase
in the cost to any Bank of agreeing to make or making, funding or maintaining
any Fixed Rate Advance to the Borrower, then the Borrower shall from time





                                      -22-
<PAGE>   29
to time, upon demand by such Bank (with a copy of such demand to the Agent),
pay to the Agent for the account of such Bank additional amounts sufficient to
compensate such Bank for such increased cost.  A certificate as to the amount
of such increased cost, submitted to the Borrower and the Agent by such Bank,
shall be prima facie evidence of the amount of such increased cost.  Promptly
after any Bank becomes aware of any such introduction, change or proposed
compliance, such Bank shall notify the Borrower thereof, provided that the
failure to provide such notice shall not affect such Bank's rights hereunder,
except that such Bank's right to recover such increased costs from the Borrower
for any period prior to such notice shall be limited to the period of (i) 180
days, if such increased cost relates to any outstanding Advance, or (ii) 90
days, in each other event, immediately prior to the date such notice is given
to the Borrower.

       (b)    If any Bank determines that compliance with any law or regulation
or any guideline or request from any central bank or other governmental
authority (whether or not having the force of law) affects or would affect the
amount of capital required or expected to be maintained by such Bank or any
corporation controlling such Bank and that the amount of such capital is
increased by or based upon the existence of such Bank's commitment to lend to
the Borrower hereunder and other commitments of this type, then, upon demand by
such Bank (with a copy of such demand to the Agent), the Borrower shall
immediately pay to the Agent for the account of such Bank, from time to time as
specified by such Bank, additional amounts sufficient to compensate such Bank
or such corporation in the light of such circumstances, to the extent that such
Bank reasonably determines such increase in capital to be allocable to the
existence of such Bank's commitment to lend hereunder.  A certificate as to
such amounts submitted to the Borrower and the Agent by such Bank shall be
conclusive and binding for all purposes, absent manifest error.

       (c)    In the event that any Bank makes a demand for payment under
Section 2.06(c) or this Section 2.11, the Borrower may within ninety days of
such demand, if no Default then exists, replace such Bank with another
commercial bank in accordance with all of the provisions of the last sentence
of Section 10.06(a) (including execution of an appropriate Assignment) provided
that (i) all obligations of such Bank to lend hereunder shall be terminated and
the A Note and any B Note payable to such Bank and all other obligations owed
to such Bank hereunder shall be purchased in full without recourse at par plus
accrued interest at or prior to such replacement, (ii) such replacement bank
shall be reasonably satisfactory to the Agent, (iii) such replacement bank
shall, from and after such replacement, be deemed for all purposes to be a
"Bank" hereunder with a Commitment in the amount of the respective Commitment
of the assigning Bank immediately prior to such replacement (plus, if such
replacement bank is already a Bank prior to such replacement, the respective
Commitment of such Bank prior to such replacement), as such amount may be
changed from time to time pursuant hereto, and shall have all of the rights,
duties and obligations hereunder of the Bank being replaced, and (iv) such
other actions shall be taken by the Borrower, such Bank and such replacement
bank as may be appropriate to effect the replacement of such Bank with such
replacement bank on terms such that such replacement bank has all of the
rights, duties and obligations hereunder as such Bank (including, without
limitation, execution and delivery of new Notes to such replacement bank,
redelivery to the Borrower in due course of the Notes payable to





                                      -23-
<PAGE>   30
such Bank and specification of the information contemplated by Schedule I as to
such replacement bank).

       Section 2.12.  Illegality.  Notwithstanding any other provision of this
Agreement, if any Bank shall notify the Agent that the introduction of or any
change in or in the interpretation of any law or regulation shall make it
unlawful, or any central bank or other governmental authority shall assert that
it is unlawful, for any Bank or its Applicable Lending Office to make any Fixed
Rate Advance or to continue to fund or maintain any Fixed Rate Advance
hereunder, then, on notice thereof to the Borrower by the Agent, (i) the
obligation of each of the Banks to make any Fixed Rate Advance of the same Type
shall be suspended until the Agent shall notify the Borrower and the Banks that
the circumstances causing such suspension no longer exist, and (ii) the
Borrower shall forthwith prepay in full all Fixed Rate Advances then
outstanding of all Banks which are affected Fixed Rate Advances, together with
all accrued interest thereon and all amounts payable pursuant to Section 2.10,
unless each Bank shall determine in good faith in its sole opinion that it is
lawful to maintain the Fixed Rate Advances made by such Bank to the end of the
Interest Period then applicable thereto.

       Section 2.13.  Taxes.

       (a) Any and all payments by the Borrower or the Guarantor hereunder or
under the Notes or any other Credit Document shall be made, in accordance with
Section 2.09, free and clear of and without deduction for any and all present
or future taxes, levies, imposts, deductions, charges or withholdings with
respect thereto, and all liabilities with respect thereto, excluding in the
case of each Bank and the Agent, taxes imposed on its income, and franchise
taxes imposed on it, by the jurisdiction under the laws of which such Bank or
the Agent (as the case may be) is organized or any political subdivision
thereof and, in the case of each Bank, taxes imposed on its income, and
franchise taxes imposed on it, by the jurisdiction of such Bank's Applicable
Lending Office or any political subdivision thereof (all such non-excluded
taxes, levies, imposts, deductions, charges, withholdings and liabilities being
hereinafter referred to as "Taxes").  If the Borrower or the Guarantor shall be
required by law to deduct any Taxes from or in respect of any sum payable by it
hereunder or under any Note or other Credit Document to any Bank or the Agent,
(i) the sum payable shall be increased as may be necessary so that after making
all required deductions (including deductions applicable to additional sums
payable under this Section 2.13) such Bank or the Agent (as the case may be)
receives an amount equal to the sum it would have received had no such
deductions been made, (ii) the Borrower or the Guarantor, as the case may be,
shall make such deductions and (iii) the Borrower or the Guarantor, as the case
may be, shall pay the full amount deducted to the relevant taxation authority
or other authority in accordance with applicable law.

       (b)    In addition, the Borrower or the Guarantor, as the case may be,
agrees to pay any present or future stamp or documentary taxes or any other
excise or property taxes, charges or similar levies which arise from any
payment made by the Borrower or the Guarantor hereunder or under any Note or
other Credit Document executed by it or from the execution, delivery or





                                      -24-
<PAGE>   31
registration of, or otherwise with respect to, this Agreement or any Note or
other Credit Document (hereinafter referred to as "Other Taxes").

       (c)    THE BORROWER AND THE GUARANTOR WILL INDEMNIFY EACH BANK, EACH CO-
AGENT, THE ARRANGER & SYNDICATION AGENT AND THE AGENT FOR THE FULL AMOUNT OF
TAXES OR OTHER TAXES (INCLUDING, WITHOUT LIMITATION, ANY TAXES OR OTHER TAXES
IMPOSED BY ANY JURISDICTION ON AMOUNTS PAYABLE UNDER THIS SECTION 2.13) OWED
AND PAID BY SUCH BANK, SUCH CO-AGENT, THE ARRANGER & SYNDICATION AGENT OR THE
AGENT (AS THE CASE MAY BE) AND ANY LIABILITY (INCLUDING PENALTIES, INTEREST AND
EXPENSES) ARISING THEREFROM OR WITH RESPECT THERETO.  THIS INDEMNIFICATION
SHALL BE MADE WITHIN 30 DAYS FROM THE DATE SUCH BANK, SUCH CO-AGENT, THE
ARRANGER & SYNDICATION AGENT OR THE AGENT (AS THE CASE MAY BE) MAKES WRITTEN
DEMAND THEREFOR.

       (d)    Within 30 days after the date of the payment of Taxes by or at
the direction of the Borrower or the Guarantor, the Borrower will furnish to
the Agent, at its address referred to in Section 10.02, the original or a
certified copy of a receipt evidencing payment thereof.

       (e)    Without prejudice to the survival of any other agreement of the
Borrower or the Guarantor hereunder, the agreements and obligations of the
Borrower and the Guarantor contained in this Section 2.13 shall survive the
payment in full of principal and interest hereunder and under the Notes and
other Credit Documents.

       (f)    Each Bank that is not incorporated under the laws of the United
States of America or a state thereof agrees that it will deliver to the
Borrower and the Agent on the date of this Agreement or upon the effectiveness
of any Assignment and Acceptance (i) two duly completed copies of United States
Internal Revenue Service Form 1001 or 4224 or successor applicable form, as the
case may be, certifying in each case that such Bank is entitled to receive
payments under this Agreement and the Notes payable to it, without deduction or
withholding of any United States federal income taxes, (ii) if applicable, an
Internal Revenue Service Form W-8 or W-9 or successor applicable form, as the
case may be, to establish an exemption from United States backup withholding
tax, and (iii) any other governmental forms which are necessary or required
under an applicable tax treaty or otherwise by law to reduce or eliminate any
withholding tax, which have been reasonably requested by the Borrower.  Each
Bank which delivers to the Borrower and the Agent a Form 1001 or 4224 and Form
W-8 or W-9 pursuant to the next preceding sentence further undertakes to
deliver to the Borrower and the Agent two further copies of the said Form 1001
or 4224 and Form W-8 or W-9, or successor applicable forms, or other manner of
certification, as the case may be, on or before the date that any such form
expires or becomes obsolete or after the occurrence of any event requiring a
change in the most recent form previously delivered by it to the Borrower and
the Agent, and such extensions or renewals thereof as may reasonably be
requested by the Borrower and the Agent certifying in the case of a Form 1001
or 4224 that such Bank is





                                      -25-
<PAGE>   32
entitled to receive payments under this Agreement without deduction or
withholding of any United States federal income taxes.  The Borrower shall
withhold tax at the rate and in the manner required by the laws of the United
States with respect to payments made to a Bank failing to timely provide the
requisite Internal Revenue Service forms.

       Section 2.14.  Payments Pro Rata.  Except as provided in Sections
2.03(b), 2.03(c), 2.03(d), 2.06(c), 2.10, 2.11, or 2.13, each of the Banks
agrees that if it should receive any payment (whether by voluntary payment, by
realization upon security, by the exercise of the right of setoff or banker's
lien, by counterclaim or cross action, by the enforcement of any right under
this Agreement or the Notes or other Credit Documents, or otherwise) in respect
of any obligation of the Borrower or Guarantor hereunder or under the Notes or
other Credit Documents of a sum which with respect to the related sum or sums
received by other Banks is in a greater proportion than the total amount of
principal, interest, fees or any other obligation incurred hereunder, as the
case may be, then owed and due to such Bank bears to the total amount of
principal, interest, fees or any such other obligation then owed and due to all
of the Banks immediately prior to such receipt, then such Bank receiving such
excess payment shall purchase for cash without recourse from the other Banks an
interest in the obligations of the Borrower to such Banks in such amount as
shall result in a proportional participation by all of the Banks in the
aggregate unpaid amount of principal, interest, fees or any such other
obligation, as the case may be, owed to all of the Banks, provided that if all
or any portion of such excess payment is thereafter recovered from such
purchasing Bank, such purchase from each other Bank shall be rescinded and each
such other Bank shall repay to the purchasing Bank the purchase price to the
extent of such other Bank's ratable share (according to the proportion of (i)
the amount of the participation purchased from such other Bank as a result of
such excess payment to (ii) the total amount of such excess payment) of such
recovery together with an amount equal to such other Bank's ratable share
(according to the proportion of (i) the amount of such other Bank's required
repayment to (ii) the total amount so recovered from the purchasing Bank) of
any interest or other amount paid or payable by the purchasing Bank in respect
of the total amount so recovered.  The Borrower agrees that any Bank so
purchasing a participation from another Bank pursuant to this Section 2.14 may,
to the fullest extent permitted by law, exercise all its rights of payment
(including the right of set-off) with respect to such participation as fully as
if such Bank were the direct creditor of the Borrower in the amount of such
participation.

       Section 2.15. Increase of Aggregate Commitments.  Provided no Default
has occurred and is continuing, the Borrower may by written notice to the Agent
and the Banks request that the aggregate amount of the Commitments hereunder be
increased up to the Aggregate Commitment Limit; provided, however that in the
event the Parallel Agreement is still in effect, (a) the Borrower shall
simultaneously request a pro rata increase in the  aggregate amount of the
Parallel Agreement Commitments pursuant to Section 2.15 of the Parallel
Agreement, and (b) after giving effect to such increase of the aggregate
Commitments and such pro rata increase of the aggregate Parallel Agreement
Commitments, the total amount of all Commitments and all Parallel Agreement
Commitments shall not exceed the Aggregate Commitment Limit.  Upon the
Borrower's receipt of (a) incremental commitments from such Banks that may
agree to provide an increased Commitment hereunder, and if the Parallel
Agreement is still in effect, an increased Parallel Agreement





                                      -26-
<PAGE>   33
Commitment under the Parallel Agreement (there being no obligation on the part
of any Bank at any time hereunder to increase such Bank's Commitment or such
Bank's Parallel Agreement Commitment but any such increase agreed upon by any
Bank to be pro rata between this Agreement and the Parallel Agreement so that
its ratable percentage of each is the same) and/or (b) commitments from new
lenders willing to become a Bank with a Commitment hereunder, and if the
Parallel Agreement is still in effect, a "Bank" under the Parallel Agreement
with a pro rata Parallel Agreement Commitment, then such increase of the
aggregate Commitments shall become effective simultaneously with any such
increase of the aggregate Parallel Agreement Commitments when the following
conditions precedent and, if applicable,  the conditions precedent set forth in
Section 2.15 of the Parallel Agreement have been satisfied and the Agent shall
have notified the parties hereto to such effect:

       (i)    The Borrower shall have delivered to the Agent, with sufficient
copies for each Bank (A) a certificate of the Chief Financial Officer of the
Borrower addressed to the Banks to the effect that, to the best of such
officer's knowledge, (x) no Default or Event of Default has occurred and is
continuing (or would result from the incurrence of the additional Debt
contemplated by this Section 2.15), and (y) all representations and warranties
herein or in any other Credit Document are true and correct in all material
respects with the same effect as if these representations and warranties had
been made on the date of such certificate (it being understood and agreed that
any representation which by its terms is made as of a specified date shall be
required to be true and correct in all material respects only as of such
specified date), and (B) unless the documentation delivered in connection with
the effectiveness of this Agreement otherwise authorizes Debt hereunder and
under the Parallel Agreement in an aggregate amount up to the Aggregate
Commitment Limit, a certificate of the Borrower's Secretary certifying that the
Borrower has been duly authorized by resolution of the Borrower's Board of
Directors to incur Debt hereunder and, if the Parallel Agreement is still in
effect, under the Parallel Agreement in an amount equal to or exceeding the
increased aggregate amount of the Commitments and, if the Parallel Agreement is
still in effect, the Parallel Agreement Commitments.

       (ii)   An Accession Agreement for each New Bank shall have been duly
executed by each party thereto.

       (iii)  The Agent has received the written consent of each Bank which has
agreed to increase  its Commitment hereunder (but no other Bank's consent shall
be required), such consent to be substantially in the form of the Consent to
Increase of Commitment attached as Exhibit G.

       (iv)   New Notes (including without limitation substitute Notes for
those Banks which have agreed to increase their respective Commitments) shall
have been executed and delivered by the Borrower in substantially the form of
Exhibits A-1 and A-2, as appropriate.

       (v)    No A Advances are outstanding hereunder as of the date such
increase is to become effective, or any such Advances are contemporaneously
repaid on such date.





                                      -27-
<PAGE>   34
                                  ARTICLE III

                                   CONDITIONS

       Section 3.01.  Conditions Precedent to Effectiveness.  This Agreement
shall become effective when the following conditions precedent have been
satisfied and the Agent shall have notified the parties hereto in writing that
this Agreement has become effective pursuant to this Section:

       (a)    Documentation.  The Agent shall have received the following duly
executed by all the parties thereto, in form and substance satisfactory to the
Agent and the Banks, and (except for the Notes) in sufficient copies for each
Bank:

              (i)    This Agreement duly executed by the Borrower, the
       Guarantor, the Agent, the Co-Agents, the Arranger & Syndication Agent
       and each Bank, and an A Note payable to each Bank duly executed by the
       Borrower.

              (ii)   A certificate of the Secretary or an Assistant Secretary
       of the Borrower certifying (i) copies of the Certificate of
       Incorporation and Bylaws of the Borrower as in effect on the date
       hereof, and (ii) the names and true signatures of the officers of the
       Borrower authorized to sign the Credit Documents executed or to be
       executed by the Borrower.

              (iii)  A certificate of the Secretary or an Assistant Secretary
       of the Guarantor certifying (i) copies of the Certificate of
       Incorporation and Bylaws of the Guarantor as in effect on the date
       hereof, and (ii) the names and true signatures of the officers of the
       Guarantor authorized to sign the Credit Documents executed or to be
       executed by the Guarantor.

              (iv)   A favorable opinion of Cullen M. Godfrey, General Counsel
       for each of the Borrower and the Guarantor, substantially in the form of
       Exhibit D hereto and as to such other matters as any Bank through the
       Agent may reasonably request.

              (v)    A favorable opinion of Messrs. Bracewell & Patterson,
       L.L.P. counsel for the Agent, substantially in the form of Exhibit E
       hereto.

              (vi)   The Agent's Fee Letter, executed by the Agent, the
       Borrower and the Guarantor.

       (b)    No Material Adverse Change.  No event or events which,
individually or in the aggregate has had or is reasonably likely to cause a
material adverse change in the business, assets, condition or operations of (i)
the Borrower and its Subsidiaries taken as a whole, or (ii) the Guarantor and
its Subsidiaries taken as a whole shall have occurred.





                                      -28-
<PAGE>   35
       (c)    Payment of Fees.  On the date of this Agreement, the Borrower
shall have paid the fees required by paragraphs (b) and (d) of Section 2.03 and
all costs and expenses which have been invoiced and are payable pursuant to
Section 10.04.

       (d)    No Default.  No Default shall have occurred and be continuing or
would result from such Borrowing or from the application of the proceeds
therefrom.

       (e)    Representations and Warranties.  The representations and
warranties contained in Article V hereof shall be true and correct in all
material respects on and as of the Effective Date before and after giving
effect to the initial Borrowing and to the application of the proceeds from
such Borrowing, as though made on and as of such date.

       (f)    Termination of Existing Credit Agreement.  The Agent, the Co-
Agents, the Arranger & Syndication Agent and the Banks shall have received
sufficient evidence indicating that the Borrower's and the Guarantor's
obligations under the U.S. $400,000,000 Credit Agreement dated as of March 7,
1995 among the Borrower, the Guarantor, the banks and co-agents parties
thereto, and NationsBank of Texas, N.A., as agent, have been repaid and all
commitments of the banks party thereto have been terminated.

       (g)    No Material Litigation.  No legal or regulatory action or
proceeding has commenced and is continuing against the Borrower, the Guarantor
or any of their Subsidiaries since the date of this Agreement which could
reasonably be expected to cause a material adverse change in the business,
assets, condition or operations of (i) the Borrower and its Subsidiaries taken
as a whole, or (ii) the Guarantor and its Subsidiaries taken as a whole.

       Section 3.02.  Conditions Precedent to Each A Borrowing.  The obligation
of each Bank to make an A Advance on the occasion of any A Borrowing (including
the initial Borrowing) shall be subject to the further conditions precedent
that on the date of such A Borrowing the following statements shall be true
(and each of the giving of the applicable Notice of A Borrowing and the
acceptance by the Borrower of the proceeds of such A Borrowing shall constitute
a representation and warranty by the Borrower that on the date of such A
Borrowing such statements are true):

       (i)    the representations and warranties contained in Article V (other
              than in Section 5.05 and Section 5.06) are correct on and as of
              the date of such A Borrowing, before and after giving effect to
              such A Borrowing and to the application of the proceeds
              therefrom, as though made on and as of such date,

       (ii)   no event has occurred and is continuing, or would result from
              such A Borrowing or from the application of the proceeds
              therefrom, which constitutes an Event of Default, and

       (iii)  after giving effect to such A Borrowing and all other Borrowings
              which have been requested on or prior to such date but which have
              not been made prior to such date,





                                      -29-
<PAGE>   36
              the aggregate principal amount of all Borrowings will not exceed
              the aggregate of the Commitments;

and the Agent shall have received such other approvals, opinions or documents
as any Bank through the Agent may reasonably request.

       Section 3.03.  Conditions Precedent to Certain Borrowings.  The
obligation of each Bank to make that portion of an A Advance on the occasion of
any A Borrowing which would increase the aggregate outstanding amount of A
Advances owing to such Bank over the aggregate amount of A Advances owing to
such Bank outstanding immediately prior to the making of such Advance shall in
each case be subject to the further condition precedent that on the date of
such Borrowing, no Default occurred and is continuing, or would result from
such Borrowing or from the application of the proceeds therefrom (and each of
the giving of the applicable Notice of Borrowing and the acceptance by the
Borrower of the proceeds of such Borrowing shall constitute a representation
and warranty by the Borrower that such condition precedent is satisfied on the
date of such Borrowing).

       Section 3.04.  Conditions Precedent to Each B Borrowing.  The obligation
of each Bank which is to make a B Advance on the occasion of a B Borrowing
(including the initial B Borrowing) to make such B Advance as part of such B
Borrowing is subject to the further conditions precedent that (a) at or before
the time required by paragraph (iii) of Section 2.08(a), the Agent shall have
received the written confirmatory notice of such B Borrowing contemplated by
such paragraph, (b) on or before the date of such B Borrowing but prior to such
B Borrowing, the Agent shall have received a B Note executed by the Borrower
payable to the order of such Bank for each of the one or more B Advances to be
made by such Bank as part of such B Borrowing, in a principal amount equal to
at least the principal amount of the B Advance to be evidenced thereby and
otherwise on such terms as were agreed to for such B Advance in accordance with
Section 2.08, and (c) on the date of such B Borrowing the following statements
shall be true (and each of the giving of the applicable Notice of B Borrowing
and the acceptance by the Borrower of the proceeds of such B Borrowing shall
constitute a representation and warranty by the Borrower that on the date of
such B Borrowing such statements are true):

       (i)    the representations and warranties contained in Article V (other
              than in Section 5.05 and 5.06) are correct on and as of the date
              of such B Borrowing, before and after giving effect to such B
              Borrowing and to the application of the proceeds therefrom, as
              though made on and as of such date,

       (ii)   no event has occurred and is continuing, or would result from
              such B Borrowing or from the application of the proceeds
              therefrom, which constitutes a Default, and

       (iii)  following the making of such B Borrowing and all other Borrowings
              to be made on the same day to the Borrower under this Agreement,
              the aggregate principal amount of all Advances then outstanding
              shall not exceed the aggregate amount of the Commitments to the
              Borrower (computed without regard to any B Reduction);





                                      -30-
<PAGE>   37
and the Agent shall have received such other approvals, opinions or documents
as any Bank through the Agent may reasonably request.


                                   ARTICLE IV

                                    GUARANTY

       Section 4.01.  Guaranty.  The Guarantor hereby unconditionally
guarantees the punctual payment of the Guaranteed Obligations when due, whether
at stated maturity, by acceleration or otherwise, and agrees to pay any and all
expenses (including counsel fees and expenses) incurred by the Agent or any
Bank in enforcing any rights hereunder.  Without limiting the generality of the
foregoing, the Guarantor's liability shall extend to all amounts which
constitute part of the Guaranteed Obligations and would be owed by the Borrower
under this Agreement or any of the Notes but for the fact that the claims to
such amounts are, or are deemed to be, stayed, unenforceable, not allowable,
discharged, or otherwise reduced, restricted or limited in any manner due to
the existence of a bankruptcy, reorganization or similar proceeding involving
the Borrower.

       Section 4.02.  Guaranty Absolute.  The Guarantor guarantees that the
Guaranteed Obligations will be paid strictly in accordance with the terms of
the Credit Documents executed from time to time by the Borrower, regardless of
any law, regulation or order now or hereafter in effect in any jurisdiction
affecting any of such terms or the rights of the Agent or any Bank with respect
thereto.  The obligations of the Guarantor hereunder are independent of the
Guaranteed Obligations, and provided an Event of Default exists as to the
Borrower and is continuing at the time an action is brought, a separate action
or actions may be brought and prosecuted against the Guarantor to enforce this
Agreement, irrespective or whether any action is brought against the Borrower
or whether the Borrower is joined in any such action or actions.  The liability
of the Guarantor hereunder shall be absolute and unconditional irrespective of:

              (i)    any lack of validity or enforceability of any of the
       Credit Documents against the Borrower;

              (ii)   any change in the time, manner or place of payment of, or
       in any other term of, all or any of the Guaranteed Obligations or any
       other liabilities, or any other amendment or waiver of or any consent to
       departure from any of the Credit Documents, including, without
       limitation, any increase in the Guaranteed Obligations or any other
       liabilities resulting from the making of additional Advances guaranteed
       by the Guarantor to the Borrower or otherwise;

              (iii)  any taking, exchange, release or non-perfection of any
       collateral, or any taking, release or amendment or waiver of or consent
       to departure from any other guaranty, for all or any of the Guaranteed
       Obligations or any other liabilities;





                                      -31-
<PAGE>   38
              (iv)   any manner of application of collateral, or proceeds
       thereof, to all or any of the Guaranteed Obligations or any other
       liabilities, or any manner of sale or other disposition of any
       collateral for all or any of the Guaranteed Obligations or any other
       liabilities or any other assets of the Borrower or any of its
       Subsidiaries;

              (v)    any change, restructuring or termination of the corporate
       structure or existence of the Borrower or any of its Subsidiaries; or

              (vi)   any other circumstances which might otherwise constitute a
       defense available to, or a discharge of, the Borrower or a guarantor.

       This guaranty shall continue to be effective or be reinstated, as the
case may be, if at any time any payment of any of the Guaranteed Obligations is
rescinded or must otherwise be returned by the Agent or any Bank upon the
insolvency, bankruptcy or reorganization of the Borrower or otherwise, all as
though such payment had not been made.

       Section 4.03.  Waiver.  The Guarantor hereby waives promptness,
diligence, notice of acceptance and any other notice with respect to any of the
Guaranteed Obligations and this Guaranty and any requirement that the Agent or
any Bank protect, secure, perfect or insure any security interest or lien or
any property subject thereto or exhaust any right to take any action against
the Borrower or any other Person or any collateral.

       Section 4.04.  Subrogation.  The Guarantor irrevocably waives any and
all rights to which it may be entitled, by operation of law or otherwise, upon
making any payment hereunder (i) to be subrogated to the rights of the Agent
and the Banks against the Borrower or any other Person with respect to such
payment or otherwise to be reimbursed, indemnified or exonerated by the
Borrower or any other Person in respect thereof or (ii) to receive any payment,
in the nature of contribution or for any other reason, from any Person who has
provided security for the Guaranteed Obligations or who has also guaranteed or
is otherwise liable for the Guaranteed Obligations with respect to which such
payment was made.  If any amount shall be paid to the Guarantor on account of
such subrogation or contribution rights at any time, such amount shall be held
in trust for the benefit of the Banks and shall forthwith be paid to the Agent
to be credited and applied upon the Guaranteed Obligations, whether matured or
unmatured, in such order as may be determined by the Agent.

       Section 4.05.  No Waiver; Remedies.  No failure on the part of the Agent
or any Bank to exercise, and no delay in exercising, any right hereunder shall
operate as a waiver thereof; nor shall any single or partial exercise of any
right hereunder preclude any other or further exercise thereof or the exercise
of any other right.  The remedies herein provided are cumulative and not
exclusive of any remedies provided by law.

       Section 4.06.  Continuing Guaranty.  This guaranty is a continuing
guaranty and shall (i) remain in full force and effect until the later of (A)
the payment in full of the Guaranteed Obligations and all other amounts payable
under this guaranty and (B) the expiration or termination





                                      -32-
<PAGE>   39
of each Commitment of each Bank to the Borrower, (ii) be binding upon the
Guarantor, its successors and assigns, (iii) inure to the benefit of, and be
enforceable by, the Agent, the Co-Agents, the Arranger & Syndication Agent, and
each of the Banks and their respective successors, transferees and assigns, and
(iv) not be terminated by the Guarantor or the Borrower.


                                   ARTICLE V

                         REPRESENTATIONS AND WARRANTIES

       Each of the Borrower and the Guarantor represents and warrants as
follows:

       Section 5.01.  Corporate Existence.  Each of the Borrower and the
Guarantor is a corporation duly organized, validly existing and in good
standing under the laws of the State of Delaware and has all corporate powers
and all governmental licenses, authorizations, certificates, consents and
approvals required to carry on its business as now conducted in all material
respects.  Each Subsidiary of the Borrower and of the Guarantor is a
corporation duly organized, validly existing and in good standing under the
laws of its jurisdiction of incorporation, except where the failure to be so
organized, existing and in good standing could not reasonably be expected to
have a material adverse effect on the business, assets, condition or operations
of (i) the Borrower and its  Subsidiaries taken as a whole, or (ii) the
Guarantor and its Subsidiaries taken as a whole.  Each such Subsidiary has all
corporate powers and all governmental licenses, authorizations, certificates,
consents and approvals required to carry on its business as now conducted in
all material respects.

       Section 5.02.  Corporate Power.  The execution, delivery and performance
by the Borrower and the Guarantor of the Credit Documents to which each is a
party and the consummation of the transactions contemplated by such Credit
Documents are within the Borrower's and the Guarantor's corporate powers,
respectively, have been duly authorized by all necessary corporate action, do
not contravene (i) the Borrower's or the Guarantor's charter or by-laws or (ii)
law or any contractual restriction binding on or affecting the Borrower or the
Guarantor and will not result in or require the creation or imposition of any
Lien prohibited by this Agreement.  At the time of each borrowing of any
Advance by the Borrower, such borrowing and the use of the proceeds of such
Advance will be within the Borrower's corporate powers, will have been duly
authorized by all necessary corporate action, will not contravene (i) the
Borrower's charter or by-laws or (ii) law or any contractual restriction
binding on or affecting the Borrower and will not result in or require the
creation or imposition of any Lien prohibited by this Agreement.

       Section 5.03.  Authorization and Approvals.  No authorization or
approval or other action by, and no notice to or filing with, any governmental
authority or regulatory body is required for the due execution, delivery and
performance by the Borrower or the Guarantor of the Credit Documents to which
each is a party or the consummation of the transactions contemplated by such
Credit Documents.  At the time of each borrowing of any Advance by the
Borrower, no authorization or





                                      -33-
<PAGE>   40
approval or other action by, and no notice to or filing with, any governmental
authority or regulatory body will be required for such borrowing or the use of
the proceeds of such Advance.

       Section 5.04.  Enforceable Obligations.  This Agreement has been duly
executed and delivered by the Borrower and the Guarantor.  This Agreement is
the legal, valid and binding obligation of the Borrower and the Guarantor
enforceable against the Borrower or the Guarantor, respectively, in accordance
with its terms, except as such enforceability may be limited by any applicable
bankruptcy, insolvency, reorganization, moratorium or similar law affecting
creditors' rights generally.  The A Notes of the Borrower are, and when
executed the B Notes of the Borrower will be, the legal, valid and binding
obligations of the Borrower enforceable against the Borrower in accordance with
their respective terms, except as such enforceability may be limited by any
applicable bankruptcy, insolvency, reorganization, moratorium or similar law
affecting creditors' rights generally.

       Section 5.05.  Financial Statements.  (a) The Consolidated and
consolidating balance sheets of the Guarantor and its Subsidiaries as at
December 31, 1995, and the related Consolidated and consolidating statements of
income and cash flows of the Guarantor and its Subsidiaries for the fiscal year
then ended, copies of which have been furnished to each Bank, and the
Consolidated and consolidating balance sheets of the Guarantor and its
Subsidiaries as at September 30, 1996, and the related Consolidated and
consolidating statements of income and cash flows of the Guarantor and its
Subsidiaries for the nine months then ended, duly certified by an authorized
financial officer of the Guarantor, copies of which have been furnished to each
Bank, fairly present (subject, in the case of such balance sheets as at
September 30, 1996, and such statements of income and cash flows for the nine
months then ended, to year-end audit adjustments) the Consolidated and
consolidating financial condition of the Guarantor and its Subsidiaries as at
such dates and the Consolidated and consolidating results of operations of the
Guarantor and its Subsidiaries for the fiscal year and nine month period,
respectively, ended on such dates, all in accordance with generally accepted
accounting principles consistently applied.  Since September 30, 1996, there
has been no material adverse change in the condition or operations of the
Guarantor or its Subsidiaries.

       (b) The consolidating balance sheets of the Guarantor and its
Subsidiaries as at December 31, 1995 and September 30, 1996 referred to in
Section 5.05(a), and the related consolidating statements of income and cash
flows of the Guarantor and its Subsidiaries for the fiscal year and nine
months, respectively, then ended referred to in Section 5.05(a), to the extent
such balance sheets and statements pertain to the Borrower, fairly present
(subject, in the case of such balance sheet as at September 30, 1996 and such
statements of income and cash flows for the nine months then ended, to year-end
audit adjustments) the Consolidated financial condition of the Borrower and its
Subsidiaries as at such dates and the Consolidated results of operations of the
Borrower and its Subsidiaries for the fiscal year and nine month period,
respectively, ended on such dates, all in accordance with generally accepted
accounting principles consistently applied.  Since September 30, 1996, there
has been no material adverse change in the condition or operations of the
Borrower or its Subsidiaries.





                                      -34-
<PAGE>   41
       Section 5.06.  Litigation.  Except as otherwise disclosed in writing by
the Borrower or the Guarantor to the Banks and the Agent after the date hereof
and approved by the Majority Banks, there is, no pending or, to the knowledge
of the Borrower or the Guarantor, threatened action or proceeding affecting the
Borrower or the Guarantor or any Subsidiary of the Borrower or the Guarantor
before any court, governmental agency or arbitrator, which could reasonably be
expected to materially and adversely affect the financial condition or
operations of the Borrower and its Subsidiaries taken as a whole, or of the
Guarantor and its Subsidiaries taken as a whole, or which purports to affect
the legality, validity, binding effect or enforceability of this Agreement or
any Note.

       Section 5.07.  Regulation U; Use of Proceeds.  Neither the Borrower nor
the Guarantor is engaged in the business of extending credit for the purpose of
purchasing or carrying margin stock (within the meaning of Regulation U issued
by the Board of Governors of the Federal Reserve System), and no proceeds of
any Advance will be used to purchase or carry any margin stock or to extend
credit to others for the purpose of purchasing or carrying any such margin
stock.  Following the application of the proceeds of each Advance, not more
than 25% of the value of the assets of the Borrower, or of the Borrower and its
Subsidiaries, which are subject to any arrangement with the Agent or any Bank
(herein or otherwise) whereby the Borrower's or any such Subsidiary's right or
ability to sell, pledge or otherwise dispose of assets is in any way restricted
will be such margin stock.

       Section 5.08.  Investment Company Act.  Neither the Borrower nor the
Guarantor is an "investment company" or a company "controlled" by an
"investment company" within the meaning of the Investment Company Act of 1940,
as amended.

       Section 5.09.  ERISA.  No Termination Event has occurred or is
reasonably expected to occur with respect to any Plan for which an
Insufficiency exists.  Neither the Guarantor nor any ERISA Affiliate of the
Guarantor has received any notification that any Multiemployer Plan is in
reorganization or has been terminated, within the meaning of Title IV of ERISA,
and the Guarantor is not aware of any reason to expect that any Multiemployer
Plan is to be in reorganization or to be terminated within the meaning of Title
IV of ERISA.

       Section 5.10.  Taxes.  As of the date of this Agreement, the United
States federal income tax returns of the Borrower and the Guarantor, and the
Subsidiaries of the Borrower and the Guarantor, have been examined through the
fiscal year ended December 31, 1989.  The Borrower and the Subsidiaries of the
Borrower have filed all United States Federal income tax returns and all other
material domestic tax returns which are required to be filed by them and have
paid, or provided for the payment before the same become delinquent of, all
taxes due pursuant to such returns or pursuant to any assessment received by
the Borrower or any such Subsidiary, other than those taxes contested in good
faith by appropriate proceedings.  The charges, accruals and reserves on the
books of the Borrower and the Subsidiaries of the Borrower in respect of taxes
are adequate.





                                      -35-
<PAGE>   42
       Section 5.11.  Holding Company.  Neither the Borrower nor the Guarantor
is a "holding company", or a "subsidiary company" of a "holding company", or an
"affiliate" of a "holding company" or of a "subsidiary company" of a "holding
company", or a "public utility" within the meaning of the Public Utility
Holding Company Act of 1935, as amended.

       Section 5.12.  Environmental Condition.  Except as set forth in any
reports filed with the Securities and Exchange Commission (copies of which have
been received by the Banks) pertaining to certain Environmental matters, the
Borrower and the Guarantor and their respective Subsidiaries are in compliance
in all material respects with all Environmental Protection Statutes to the
extent material to their respective operations or financial condition.  As of
the date of this Agreement, there are no material Environmental matters
outstanding.  The aggregate contingent and non-contingent liabilities of the
Borrower, the Guarantor and their respective Subsidiaries which are reasonably
expected to arise in connection with (i) the requirements of Environmental
Protection Statutes or (ii) any obligation or liability to any Person in
connection with any Environmental matters (including, without limitation, any
release or threatened release (as such terms are defined in the Comprehensive
Environmental Response, Compensation and Liability Act of 1980) of any
Hazardous Waste, Hazardous Substance, other waste, petroleum or petroleum
products into the Environment) does not exceed 10% of the Consolidated Tangible
Net Worth of the Guarantor (excluding liabilities to the extent covered by
insurance if the insurer has confirmed that such insurance covers such
liabilities).

       Section 5.13.  Ownership of Borrower.  The Guarantor owns 100% of the
outstanding shares of capital stock of the Borrower, and will derive
substantial direct and indirect benefit from the transactions contemplated by
this Agreement.

       Section 5.14.  Guarantor's Independent Decision.  The Guarantor has,
independently and without reliance upon the Agent or any Bank, and based on
documents and information as it has deemed appropriate, made its own credit
analysis and decision to enter into this Agreement and to undertake the
guaranty set forth in Article IV hereof.


                                   ARTICLE VI

                             AFFIRMATIVE COVENANTS

       So long as any Note shall remain unpaid or any Bank shall have any
Commitment hereunder, unless the Majority Banks shall otherwise consent in
writing:

       Section 6.01.  Compliance with Laws, Etc.  Each of the Borrower and the
Guarantor will comply, and cause each of its Subsidiaries to comply, in all
material respects with all applicable laws, rules, regulations and orders, such
compliance to include, without limitation, the payment and discharge before the
same become delinquent of all taxes, assessments and governmental charges or
levies imposed upon it or any of its Subsidiaries or upon any of its property
or any property of any of its Subsidiaries, and all lawful claims which, if
unpaid, might become a Lien upon any property





                                      -36-
<PAGE>   43
of it or any of its Subsidiaries, provided that neither the Borrower nor the
Guarantor nor any Subsidiary of the Borrower or the Guarantor shall be required
to pay any such tax, assessment, charge, levy or claim which is being contested
in good faith and by proper proceedings and with respect to which reserves in
conformity with generally accepted accounting principles, if required by such
principles, have been provided on the books of the Borrower or the Guarantor or
such Subsidiary, as the case may be.

       Section 6.02.  Reporting Requirements.  The Guarantor will furnish to
each of the Banks:

       (a)    as soon as possible and in any event within five days after the
occurrence of each Default continuing on the date of such statement, a
statement of an authorized financial officer of the Borrower or the Guarantor,
as the case may be, setting forth the details of such Default and the actions,
if any, which the Borrower or the Guarantor has taken and proposes to take with
respect thereto;

       (b)    as soon as available and in any event not later than 60 days
after the end of each of the first three quarters of each fiscal year of the
Guarantor, the Consolidated and consolidating balance sheets of the Guarantor
and its Subsidiaries as of the end of such quarter (such consolidating balance
sheets to reflect such Subsidiaries, including the Borrower, as separate
entities) and the Consolidated and consolidating statements of income and cash
flow statements of the Guarantor and its Subsidiaries for the period commencing
at the end of the previous year and ending with the end of such quarter (such
consolidating statements of income and cash flow statements to reflect such
Subsidiaries, including the Borrower, as separate entities), all in reasonable
detail and duly certified (subject to year-end audit adjustments) by an
authorized financial officer of the Guarantor as having been prepared in
accordance with generally accepted accounting principles, together with a
certificate of said officer (i) stating that he has no knowledge that a Default
has occurred, or, if a Default has occurred and is continuing, a statement as
to the nature thereof and the action, if any, which the Guarantor proposes to
take with respect thereto, and (ii) showing in detail the calculation
supporting such statement in respect of Section 7.01;

       (c)    as soon as available and in any event not later than 120 days
after the end of each fiscal year of the Guarantor, a copy of the annual audit
report for such year for the Guarantor and its Subsidiaries, including therein
Consolidated and consolidating balance sheets of the Guarantor and its
Subsidiaries as of the end of such fiscal year (such consolidating balance
sheets to reflect such Subsidiaries, including the Borrower, as separate
entities) and Consolidated and consolidating statements of income and cash flow
statements of the Guarantor and its Subsidiaries for such fiscal year (such
consolidating statements of income and cash flow statements to reflect such
Subsidiaries, including the Borrower, as separate entities), in each case
prepared in accordance with generally accepted accounting principles and
certified by KPMG Peat Marwick or other independent certified public
accountants of recognized standing acceptable to the Majority Banks, together
with a certificate of such accounting firm to the Banks (i) stating that, in
the course of the regular audit of the business of the Guarantor and its
Subsidiaries, which audit was conducted by such accounting firm in accordance
with generally accepted auditing standards, such accounting firm has obtained





                                      -37-
<PAGE>   44
no knowledge that a Default has occurred and is continuing, or if, in the
opinion of such accounting firm, a Default has occurred and is continuing, a
statement as to the nature thereof, and (ii) showing in detail the calculations
supporting such statement in respect of Section 7.01;

       (d)    promptly after the end of each fiscal quarter, copies of all
proxy material, reports and other information which the Guarantor sends to any
of its security holders, and copies of all reports and registration statements
which the Guarantor or any Subsidiary of the Guarantor files with the
Securities and Exchange Commission or any national securities exchange;

       (e)    as soon as possible and in any event (i) within 30 Business Days
after the Guarantor or any ERISA Affiliate of the Guarantor knows or has reason
to know that any Termination Event described in clause (i) of the definition of
Termination Event with respect to any Plan has occurred and (ii) within 10
Business Days after the Guarantor or any ERISA Affiliate of the Guarantor knows
or has reason to know that any other Termination Event with respect to any Plan
has occurred or is reasonably expected to occur, a statement of the chief
financial officer or chief accounting officer of the Guarantor describing such
Termination Event and the action, if any, which the Guarantor or such ERISA
Affiliate of the Guarantor proposes to take with respect thereto;

       (f)    promptly after receipt thereof by the Guarantor or any ERISA
Affiliate of the Guarantor, copies of each notice received by the Guarantor or
any ERISA Affiliate of the Guarantor from the PBGC stating its intention to
terminate any Plan or to have a trustee appointed to administer any Plan;

       (g)    within 30 days following request therefor by any Bank, copies of
each Schedule B (Actuarial Information) to each annual report (Form 5500
Series) of the Guarantor or any ERISA Affiliate of the Guarantor with respect
to each Plan;

       (h)    promptly after receipt thereof by the Guarantor or any ERISA
Affiliate of the Guarantor from the sponsor of a Multiemployer Plan, a copy of
each notice received by the Guarantor or any ERISA Affiliate of the Guarantor
concerning (i) the imposition of a Withdrawal Liability by a Multiemployer
Plan, (ii) the determination that a Multiemployer Plan is, or is expected to
be, in reorganization within the meaning of Title IV of ERISA, (iii) the
termination of a Multiemployer Plan within the meaning of Title IV of ERISA, or
(iv) the amount of liability incurred, or expected to be incurred, by the
Guarantor or any ERISA Affiliate of the Guarantor in connection with any event
described in clause (i), (ii) or (iii) above;

       (i)    promptly after it has knowledge of (A) any material litigation
pending or threatened against it which could reasonably be expected to cause a
material adverse change in the financial condition of the Borrower, the
Guarantor, or any Subsidiary, or (B) the occurrence of any other contingency
which could reasonably be expected to cause a material adverse change in the
financial condition of the Borrower, the Guarantor or any Subsidiary; and





                                      -38-
<PAGE>   45
       (j)    such other information respecting the business or properties, or
the condition or operations, financial or otherwise, of the Borrower or the
Guarantor or any of their Subsidiaries as any Bank through the Agent may from
time to time reasonably request.

       Section 6.03.  Use of Proceeds.  The Borrower will use the proceeds of
the Advances only for general corporate purposes, including without limitation
to repay maturing commercial paper of the Borrower.

       Section 6.04.  Maintenance of Insurance.  Each of the Borrower and the
Guarantor will maintain, and cause each of its Subsidiaries to maintain,
insurance with responsible and reputable insurance companies or associations in
such amounts and covering such risks as is usually carried by companies engaged
in similar businesses and owning similar properties in the same general areas
in which the Borrower or the Guarantor or its respective Subsidiaries operate,
provided that the Borrower or the Guarantor or any of its respective
Subsidiaries may self-insure to the extent and in the manner normal for
companies of like size, type and financial condition.

       Section 6.05.  Preservation of Corporate Existence, Etc.  Each of the
Borrower and the Guarantor will preserve and maintain, and cause each of its
Subsidiaries to preserve and maintain, its corporate existence, rights,
franchises and privileges in the jurisdiction of its incorporation, and qualify
and remain qualified, and cause each Subsidiary to qualify and remain
qualified, as a foreign corporation in each jurisdiction in which qualification
is necessary or desirable in view of its business and operations or the
ownership of its properties, except in the case of any Subsidiary where the
failure of such Subsidiary to so preserve, maintain, qualify and remain
qualified could not reasonably be expected to have a material adverse effect on
the business, assets, condition or operations of the Borrower and its
Subsidiaries taken as a whole, or of the Guarantor and its Subsidiaries taken
as a whole; provided, however, that nothing herein contained shall prevent any
transaction permitted by Section 7.03.

       Section 6.06.  Payment of Taxes, Etc.  Each of the Borrower and the
Guarantor will pay and discharge, and cause each of its Subsidiaries to pay and
discharge, before the same shall become delinquent and which the failure to
timely pay or discharge could reasonably be expected to have a material adverse
effect on the business, assets, condition or operations of the Borrower and its
Subsidiaries taken as a whole, or of the Guarantor and its Subsidiaries taken
as a whole, (a) all taxes, assessments and governmental charges or levies
imposed upon it or upon its income or profits of property that are material in
amount, prior to the date on which penalties attach thereto and (b) all lawful
claims that are material in amount which, if unpaid, might by law become a Lien
upon its property; provided, however, that neither the Borrower, the Guarantor,
nor any such Subsidiary shall be required to pay or discharge any such tax,
assessment, charge, levy, or claim which is being contested in good faith and
by appropriate proceedings, and with respect to which reserves in conformity
with generally accepted accounting principles have been provided.

       Section 6.07.  Visitation Rights.  At any reasonable time and from time
to time and so long as any visit or inspection will not unreasonably interfere
with the operations of the Borrower, the





                                      -39-
<PAGE>   46
Guarantor or any of their Subsidiaries, upon reasonable notice, each of the
Borrower and the Guarantor will, and will cause its Subsidiaries to, permit the
Agent and any Bank or any of its agents or representatives thereof, to examine
and make copies of and abstracts from the records and books of account of, and
visit and inspect at its reasonable discretion the properties of, the Borrower,
the Guarantor and any such Subsidiary, to discuss the affairs, finances and
accounts of the Borrower, the Guarantor and any such Subsidiary with any of
their respective officers or directors.

                                  ARTICLE VII

                               NEGATIVE COVENANTS

       So long as any Note shall remain unpaid or any Bank shall have any
Commitment to the Borrower hereunder, without the written consent of the
Majority Banks:

       Section 7.01.  Financial Covenants.  The Guarantor will not:  (a)
declare or make any Restricted Payments unless (i) no Default or Event of
Default shall have occurred and be continuing, and (ii) the amount of all such
Restricted Payments made on or after January 1, 1997 shall not exceed an amount
equal to (x) $275,000,000, plus (y) 75% of the Guarantor's Consolidated net
income for the period on or after January 1, 1997 to the date on which such
Restricted Payment is to be made (minus 100% of cumulative losses), plus (z)
100% of the net cash proceeds of any capital stock offering of the Guarantor
effective on or after January 1, 1997; or

       (b) as of the last day of each calendar quarter, permit the Consolidated
Debt of the Guarantor to exceed 50% of the Consolidated Capitalization of the
Guarantor.

       Section 7.02.  Liens, Etc.  Neither the Borrower nor the Guarantor will
create, assume, incur or suffer to exist, or permit any of the Restricted
Subsidiaries to create, assume, incur or suffer to exist, any Lien on or in
respect of any of its property, whether now owned or hereafter acquired, or
assign or otherwise convey, or permit any such Restricted Subsidiary to assign
or otherwise convey, any right to receive income, in each case to secure or
provide for the payment of any Debt of any Person, except Permitted Liens.

       Section 7.03.  Merger and Sale of Assets.  Neither the Borrower nor the
Guarantor will merge or consolidate with or into any other Person, or sell,
lease or otherwise transfer a Substantial Part of the assets of the Guarantor
and the Restricted Subsidiaries, or permit any of the Restricted Subsidiaries
to merge or consolidate with or into any other Person, or sell, lease or
otherwise transfer a Substantial Part of the assets of the Guarantor and the
Restricted Subsidiaries, except that this Section 7.03 shall not prohibit:

              (i) a sale of any account receivable without recourse or any
       discount of an account receivable provided that (A) in the case of such
       a sale, the sale proceeds are not less than the greater of either the
       face value or the fair market value of such receivable and (B) in the
       case





                                      -40-
<PAGE>   47
       of such a discount, the discount does not exceed the greater of 20% of
       either the face value or the fair market value of such receivable;

              (ii) the Guarantor and the Restricted Subsidiaries from selling
       any assets if 100% of the net proceeds of such sale are (1) reinvested
       in the Guarantor's or the Borrower's business; (2) used to repay
       outstanding Debt of the Guarantor or the Borrower; or (3) used to make
       Restricted Payments permitted by Section 7.01(a); and

              (iii) any of the Guarantor or a Restricted Subsidiary from
       merging or consolidating with or into any Person, or transferring a
       Substantial Part of the assets of the Guarantor and the Restricted
       Subsidiaries to such Person, if in each case (x) such Person is a
       corporation organized under the laws of the United States or any state
       thereof, (y) such Person expressly assumes in writing all obligations of
       the Borrower and the Guarantor hereunder, and (z) no Default or Event of
       Default has occurred and is continuing.

       Section 7.04.  Agreements to Restrict Dividends and Certain Transfers.
Neither the Borrower nor the Guarantor will enter into or suffer to exist, or
permit any of its Subsidiaries to enter into or suffer to exist, any consensual
encumbrance or restriction on the ability of any Subsidiary of the Guarantor
(i) to pay, directly or indirectly, dividends or make any other distributions
in respect of its capital stock or pay any Debt or other obligation owed to the
Guarantor or to any Subsidiary of the Guarantor; or (ii) to make loans or
advances to the Guarantor or any Subsidiary of the Guarantor, except those
encumbrances and restrictions existing on the date hereof and described in
Schedule IV and those now or hereafter existing that are not more restrictive
in any respect than such encumbrances and restrictions described in Schedule
IV.

       Section 7.05.  Compliance with ERISA.  The Guarantor will not (i)
terminate, or permit any ERISA Affiliate of the Guarantor to terminate, any
Plan so as to result in any liability of the Guarantor or any such ERISA
Affiliate to the PBGC in excess of $5,000,000, or (ii) permit to exist any
occurrence of any Termination Event with respect to a Plan for which there is
an Insufficiency in excess of $5,000,000.

       Section 7.06.  Transactions with Affiliates.  Neither the Borrower nor
the Guarantor will make any material sale to, make any material purchase from,
extend material credit to, make material payment for services rendered by, or
enter into any other material transaction with, or permit any Restricted
Subsidiary to make any material sale to, make any material purchase from,
extend material credit to, make material payment for services rendered by, or
enter into any other material transaction with, any Affiliate of the Borrower
or the Guarantor or of such Restricted Subsidiary unless as a whole such sales,
purchases, extensions of credit, rendition of services and other transactions
are (at the time such sale, purchase, extension of credit, rendition of
services or other transaction is entered into) (i) in the ordinary course of
business, (ii) upon terms no less favorable to the Borrower or the Guarantor or
such Restricted Subsidiary than it would obtain in a comparable





                                      -41-
<PAGE>   48
arms-length transaction with a Person not an Affiliate, and (iii) on terms and
conditions reasonably fair in all material respects to the Borrower or the
Guarantor or such Restricted Subsidiary in the good faith judgment of the
Borrower or the Guarantor, as the case may be.

       Section 7.07.  Change of Business.  Neither the Borrower nor the
Guarantor will, or will permit any Restricted Subsidiary to, materially change
the general nature of its business.

       Section 7.08.  Limitation on Loans, Advances and Investments.  Neither
the Borrower nor the Guarantor will, or will permit any Restricted Subsidiary
to, make or permit to exist any loans, advances or capital contributions to, or
make any investment in, or purchase or commit to purchase any stock or other
securities or evidences of indebtedness of or interests in any Person, except
the following:

       (a)    as shown on the attached Schedule V;

       (b)    the purchase of Liquid Investments;

       (c)    trade and customer accounts receivable which are for goods
furnished or services rendered in the ordinary course of business and are
payable in accordance with customary trade terms;

       (d)    ordinary course of business contributions, loans or advances to,
or investments in, a Restricted Subsidiary; and

       (e)    other capital investments not otherwise permitted by this Section
7.08 in any Person not a Restricted Subsidiary provided that (i) the aggregate
amount of such investments for the Borrower, the Guarantor, and all Restricted
Subsidiaries which are outstanding at any time shall not exceed $25,000,000;
(ii) such Person shall be in the same or substantially similar line or lines of
business as the Guarantor and the Restricted Subsidiaries; and (iii) the
liabilities of such other Person shall be nonrecourse to the Guarantor and the
Restricted Subsidiaries.

       Section 7.09.  Fiscal Year; Accounting Practices.  Neither the Borrower
nor the Guarantor will change, or will permit any Restricted Subsidiary to
change (a) its fiscal year from that existing as of the date of this Agreement,
or (b) its accounting principles and practices (except as may be required by
reason of a change in generally accepted accounting principles) from those
reflected in the financial statements referred to in Section 5.05 in any manner
which would materially affect any accounting determination contemplated by this
Agreement.





                                      -42-
<PAGE>   49
                                  ARTICLE VIII

                               EVENTS OF DEFAULT

       Section 8.01.  Events of Default.  If any of the following events
("Events of Default") shall occur and be continuing:

       (a)    the Borrower shall fail to pay any principal of any Advance when
the same becomes due and payable in accordance with the terms hereof, or shall
fail to pay any interest on any such Advance or any fee or other amount to be
paid by it hereunder within five days after the same becomes due and payable in
accordance with the terms hereof; or

       (b)    any certification, representation or warranty made by the
Borrower or the Guarantor herein or by the Borrower or the Guarantor (or any of
their respective officers) in writing (including representations and warranties
deemed made pursuant to Section 3.02, 3.03 or 3.04) under or in connection with
any Credit Document shall prove to have been incorrect in any material respect
when made or deemed made; or

       (c)    the Borrower or the Guarantor shall fail to perform or observe
(i) any term, covenant or agreement contained in Section 6.02 on its part to be
performed or observed and such failure shall continue for three Business Days
after the earlier of the date notice thereof shall have been given to the
Borrower or the Guarantor by the Agent or any Bank or the date the Borrower or
the Guarantor shall have knowledge of such failure, or (ii) any covenant
contained in Section 6.05 (other than with respect to maintaining the corporate
existence of the Borrower or the Guarantor or maintaining any franchise of the
Borrower or the Guarantor which is material to the Borrower's or the
Guarantor's business and operations) and such failure shall continue for 30
days after the earlier of the date notice thereof shall have been given to the
Borrower or the Guarantor by the Agent or any Bank or the date the Borrower or
the Guarantor shall have knowledge of such failure, or (iii) any term (other
than a representation and warranty), covenant or agreement contained in any
Credit Document (other than a term, covenant or agreement the noncompliance
with which would be governed by clauses (i) and (ii) of this paragraph (c)) on
its part to be performed or observed; or

       (d)    the Borrower, the Guarantor, or any Restricted Subsidiary shall
fail to pay any principal of or premium or interest on any of its Debt which is
outstanding in a principal amount of at least $25,000,000 in the aggregate
(excluding Debt evidenced by the Notes) when the same becomes due and payable
(whether by scheduled maturity, required prepayment, acceleration, demand or
otherwise), and such failure shall continue after the applicable grace period,
if any, specified in the agreement or instrument relating to such Debt; or any
other event shall occur or condition shall exist under any agreement or
instrument relating to any such Debt and shall continue after the applicable
grace period, if any, specified in such agreement or instrument, if the effect
of such event or condition is to accelerate, or to permit the acceleration of,
the maturity of such Debt;





                                      -43-
<PAGE>   50
or any such Debt shall be declared to be due and payable, or required to be
prepaid (other than by a regularly scheduled required prepayment), prior to the
stated maturity thereof; or

       (e)    the Borrower, the Guarantor, or any Restricted Subsidiary shall
generally not pay its debts as such debts become due, or shall admit in writing
its inability to pay its debts generally, or shall make a general assignment
for the benefit of creditors; or any proceeding shall be instituted by or
against the Borrower, the Guarantor, or any Restricted Subsidiary seeking to
adjudicate it a bankrupt or insolvent, or seeking liquidation, winding up,
reorganization, arrangement, adjustment, protection, relief, or composition of
it or its debts under any law relating to bankruptcy, insolvency or
reorganization or relief of debtors, or seeking the entry of an order for
relief or the appointment of a receiver, trustee, or other similar official for
it or for any substantial part of its property and, in the case of any such
proceeding instituted against it (but not instituted by it), shall remain
undismissed or unstayed for a period of 30 days; or the Borrower, the
Guarantor, or any Restricted Subsidiary shall take any corporate action to
authorize any of the actions set forth above in this subsection (e); or

       (f)    any judgments or orders for the payment of money in excess of
$10,000,000 individually or $25,000,000 in the aggregate shall be rendered
against the Borrower, the Guarantor, or any Restricted Subsidiary and remain
unsatisfied and either (i) enforcement proceedings shall have been commenced by
any creditor upon such judgments or orders or (ii) there shall be any period of
30 consecutive days during which a stay of enforcement of such judgments or
orders, by reason of a pending appeal or otherwise, shall not be in effect; or

       (g)    any Termination Event with respect to a Plan shall have occurred
and, 30 days after notice thereof shall have been given to the Borrower and the
Guarantor by the Agent, (i) such Termination Event shall still exist and (ii)
the sum (determined as of the date of occurrence of such Termination Event) of
the Insufficiency of such Plan and the Insufficiency of any and all other Plans
with respect to which a Termination Event shall have occurred and then exist
(or in the case of a Plan with respect to which a Termination Event described
in clause (ii) of the definition of Termination Event shall have occurred and
then exist, the liability related thereto) is equal to or greater than
$10,000,000; or

       (h)    the Guarantor or any ERISA Affiliate of the Guarantor shall have
been notified by the sponsor of a Multiemployer Plan that it has incurred
Withdrawal Liability to such Multiemployer Plan in an amount which, when
aggregated with all other amounts required to be paid to Multiemployer Plans in
connection with Withdrawal Liabilities (determined as of the date of such
notification), exceeds $10,000,000 in the aggregate or requires payments
exceeding $5,000,000 per annum; or

       (i)    the Guarantor or any ERISA Affiliate of the Guarantor shall have
been notified by the sponsor of a Multiemployer Plan that such Multiemployer
Plan is in reorganization or is being





                                      -44-
<PAGE>   51
terminated, within the meaning of Title IV of ERISA, if as a result of such
reorganization or termination the aggregate annual contributions of the
Guarantor and its ERISA Affiliates to all Multiemployer Plans which are then in
reorganization or being terminated have been or will be increased over the
amounts contributed to such Multiemployer Plans for the respective plan years
which include the date hereof by an amount exceeding $10,000,000; or

       (j)    the Guarantor shall cease to own directly or indirectly 100% of
the capital stock of the Borrower; or

       (k)    any Person or group (or any Affiliate of such Person or group) --
other than Petrofina S.A., a societe anonyme (corporation) organized and
existing under the laws of the Kingdom of Belgium ("Petrofina"), or Petrofina
Delaware, Incorporated, a Delaware corporation ("PDI"), or any wholly-owned
Subsidiary of Petrofina or PDI --  shall beneficially own, directly or
indirectly, capital stock of the Guarantor representing 30% or more of the
voting power of all capital stock of the Guarantor; or

       (l)    any "Event of Default" (as such term is defined in the Parallel
Agreement) shall occur and be continuing.

then, and in any such event, the Agent (i) shall at the request, or may with
the consent, of the Majority Banks, by notice to the Borrower, declare all of
the Commitments and the obligation of each Bank to make Advances to be
terminated, whereupon all of the Commitments and each such obligation shall
forthwith terminate, and (ii) shall at the request, or may with the consent of
the Majority Banks, by notice to the Borrower declare the Notes, all interest
thereon and all other amounts payable by the Borrower and the Guarantor under
this Agreement to be forthwith due and payable, whereupon such Notes, such
interest and all such amounts shall become and be forthwith due and payable,
without requirement of any presentment, demand, protest, notice of intent to
accelerate, further notice of acceleration or other further notice of any kind
(other than the notice expressly provided for above), all of which are hereby
expressly waived by the Borrower and the Guarantor; provided, however, that in
the event of any Event of Default described in Section 8.01(e) with respect to
the Borrower or the Guarantor, (A) the obligation of each Bank to make Advances
shall automatically be terminated and (B) the Notes, all such interest and all
such amounts shall automatically become and be due and payable, without
presentment, demand, protest, notice of intent to accelerate, notice of
acceleration or any other notice of any kind, all of which are hereby expressly
waived by the Borrower and the Guarantor.





                                      -45-
<PAGE>   52
                                   ARTICLE IX

         THE AGENT, THE CO-AGENTS, AND THE ARRANGER & SYNDICATION AGENT

       Section 9.01.  Authorization and Action.  Each Bank hereby appoints and
authorizes the Agent to take such action as agent on its behalf and to exercise
such powers under the Credit Documents as are delegated to the Agent by the
terms hereof and thereof, together with such powers as are reasonably
incidental thereto.  As to any matters not expressly provided for by the Credit
Documents (including, without limitation, enforcement or collection of the
Notes), the Agent shall not be required to exercise any discretion or take any
action, but shall be required to act or to refrain from acting (and shall be
fully protected in so acting or refraining from acting) upon the instructions
of the Majority Banks, and such instructions shall be binding upon all Banks
and all holders of Notes; provided, however, that the Agent shall not be
required to take any action which exposes the Agent to personal liability or
which is contrary to any Credit Document or applicable law.  The Agent agrees
to give to each Bank prompt notice of each notice given to it by the Borrower
pursuant to the terms of this Agreement.

       Section 9.02.  Agent's Reliance, Etc.  Neither the Agent nor any of its
directors, officers, agents or employees shall be liable for any action taken
or omitted to be taken by it or them under or in connection with the Credit
Documents, except for its or their own gross negligence or willful misconduct.
Without limitation of the generality of the foregoing, the Agent:  (i) may
treat the payee of any Note as the holder thereof until the Agent receives and
accepts an Assignment executed by the Borrower, the Bank which is the payee of
such Note, as assignor, and the assignee in accordance with Section 10.06; (ii)
may consult with legal counsel (including counsel for the Borrower),
independent public accountants and other experts selected by it and shall not
be liable for any action taken or omitted to be taken in good faith by it in
accordance with the advice of such counsel, accountants or experts; (iii) makes
no warranty or representation to any Bank and shall not be responsible to any
Bank for any statements, warranties or representations made in or in connection
with the Credit Documents; (iv) shall not have any duty to ascertain or to
inquire as to the performance or observance of any of the terms, covenants or
conditions of the Credit Documents on the part of the Borrower or the Guarantor
or to inspect the property (including the books and records) of the Borrower or
the Guarantor; (v) shall not be responsible to any Bank for the due execution,
legality, validity, enforceability, genuineness, sufficiency or value of the
Credit Documents; and (vi) shall incur no liability under or in respect of the
Credit Documents by acting upon any notice, consent, certificate or other
instrument or writing (which may be by telecopier, telegram, cable or telex)
believed by it to be genuine and signed or sent by the proper party or parties.

       Section 9.03.  NationsBank and Affiliates.  With respect to its
Commitment, the Advances made by it and the Notes issued to it, NationsBank
shall have the same rights and powers under the Credit Documents and any Note
payable to NationsBank as any other Bank and may exercise the same as though it
was not the Agent; and the term "Bank" or "Banks" shall, unless otherwise





                                      -46-
<PAGE>   53
expressly indicated, include NationsBank in its individual capacity.
NationsBank and its affiliates may accept deposits from, lend money to, act as
trustee under indentures of, and generally engage in any kind of business with,
the Borrower, the Guarantor, any Subsidiary of the Borrower or the Guarantor
and any Person who may do business with or own securities of the Borrower, the
Guarantor, or any such Subsidiary, all as if NationsBank were not the Agent and
without any duty to account therefor to the Banks.

       Section 9.04.  Bank Credit Decision.  Each Bank acknowledges that it
has, independently and without reliance upon the Agent, the Arranger &
Syndication Agent or any other Bank and based on the financial statements
referred to in Section 5.05 and such other documents and information as it has
deemed appropriate, made its own credit analysis and decision to enter into
this Agreement.  Each Bank also acknowledges that it will, independently and
without reliance upon the Agent, the Arranger & Syndication Agent or any other
Bank and based on such documents and information as it shall deem appropriate
at the time, continue to make its own credit decisions in taking or not taking
action under the Credit Documents.

       SECTION 9.05.  INDEMNIFICATION.  THE BANKS AGREE TO INDEMNIFY THE AGENT,
EACH CO-AGENT, AND THE ARRANGER & SYNDICATION AGENT (TO THE EXTENT NOT
REIMBURSED BY THE BORROWER OR THE GUARANTOR), RATABLY ACCORDING TO THE
RESPECTIVE PRINCIPAL AMOUNTS OF THE A NOTES THEN HELD BY EACH OF THEM (OR IF NO
A NOTES ARE AT THE TIME OUTSTANDING OR IF ANY A NOTES ARE HELD BY PERSONS WHICH
ARE NOT BANKS, RATABLY ACCORDING TO EITHER (I) THE RESPECTIVE AMOUNTS OF THEIR
COMMITMENTS, OR (II) IF ALL COMMITMENTS HAVE TERMINATED, THE RESPECTIVE AMOUNTS
OF THE COMMITMENTS IMMEDIATELY PRIOR TO THE TIME THE COMMITMENTS TERMINATED),
FROM AND AGAINST ANY AND ALL LIABILITIES, OBLIGATIONS, LOSSES, DAMAGES,
PENALTIES, ACTIONS, JUDGMENTS, SUITS, COSTS, EXPENSES OR DISBURSEMENTS OF ANY
KIND OR NATURE WHATSOEVER WHICH MAY BE IMPOSED ON, INCURRED BY, OR ASSERTED
AGAINST THE AGENT, SUCH CO-AGENT OR THE ARRANGER & SYNDICATION AGENT IN ANY WAY
RELATING TO OR ARISING OUT OF THE CREDIT DOCUMENTS OR ANY ACTION TAKEN OR
OMITTED BY THE AGENT UNDER THE CREDIT DOCUMENTS, PROVIDED THAT NO BANK SHALL BE
LIABLE TO THE AGENT, SUCH CO-AGENT OR THE ARRANGER & SYNDICATION AGENT FOR ANY
PORTION OF SUCH LIABILITIES, OBLIGATIONS, LOSSES, DAMAGES, PENALTIES, ACTIONS,
JUDGMENTS, SUITS, COSTS, EXPENSES OR DISBURSEMENTS RESULTING FROM THE AGENT'S,
SUCH CO-AGENT'S OR THE ARRANGER & SYNDICATION AGENT'S GROSS NEGLIGENCE OR
WILLFUL MISCONDUCT.  WITHOUT LIMITATION OF THE FOREGOING, EACH BANK AGREES TO
REIMBURSE THE AGENT PROMPTLY UPON DEMAND FOR ITS RATABLE SHARE OF ANY
OUT-OF-POCKET EXPENSES (INCLUDING COUNSEL





                                      -47-
<PAGE>   54
FEES) INCURRED BY THE AGENT IN CONNECTION WITH THE PREPARATION, EXECUTION,
DELIVERY, ADMINISTRATION, MODIFICATION, AMENDMENT OR ENFORCEMENT (WHETHER
THROUGH NEGOTIATIONS, LEGAL PROCEEDINGS OR OTHERWISE) OF, OR LEGAL ADVICE IN
RESPECT OF RIGHTS OR RESPONSIBILITIES UNDER, THE CREDIT DOCUMENTS TO THE EXTENT
THAT THE AGENT IS NOT REIMBURSED FOR SUCH EXPENSES BY THE BORROWER OR THE
GUARANTOR.

       Section 9.06.  Successor Agent.  The Agent may resign at any time as
Agent under this Agreement by giving written notice thereof to the Banks and
the Borrower and may be removed at any time by the Borrower if at any time the
Agent, in its individual capacity as a Bank hereunder, shall hold less than
$30,000,000 of the aggregate Commitments.  Upon any such resignation or
removal, the Borrower shall have the right to appoint, with the consent of the
Majority Banks (which consent shall not be unreasonably withheld), a successor
Agent.  If no successor Agent shall have been so appointed by the Borrower with
such consent of the Majority Banks, and shall have accepted such appointment,
within 30 days after the retiring Agent's giving of notice of resignation or
the Borrower's removal of the retiring Agent, then the retiring Agent may, on
behalf of the Banks, appoint a successor Agent, which shall be a Bank which is
a commercial bank organized under the laws of the United States of America or
of any State thereof and having a combined capital and surplus of at least
$500,000,000.  Upon the acceptance of any appointment as Agent under this
Agreement by a successor Agent, such successor Agent shall thereupon succeed to
and become vested with all the rights, powers, privileges and duties of the
retiring Agent and shall function as the Agent under this Agreement, and the
retiring Agent shall be discharged from its duties and obligations as Agent
under this Agreement.  After any retiring Agent's resignation or removal
hereunder as Agent, the provisions of this Article IX shall inure to its
benefit as to any actions taken or omitted to be taken by it while it was Agent
under this Agreement.

       Section 9.07.  Co-Agents; Arranger & Syndication Agent.  The Co-Agents
and the Arranger & Syndication Agent shall have no duties, obligations, or
liabilities in their capacities as such.


                                   ARTICLE X

                                 MISCELLANEOUS

       Section 10.01.  Amendments, Etc.  No amendment or waiver of any
provision of any Credit Document, nor consent to any departure by the Borrower
or the Guarantor therefrom, shall in any event be effective unless the same
shall be in writing and signed by the Borrower and the Majority Banks, and then
such waiver or consent shall be effective only in the specific instance and for
the specific purpose for which given; provided, however, that no amendment,
waiver or consent shall, unless in writing and signed by all the Banks, do any
of the following:  (a) waive any of the





                                      -48-
<PAGE>   55
conditions specified in Article III, (b) increase the aggregate amount of the
Commitments to greater than the Aggregate Commitment Limit or subject the Banks
to any additional obligations, (c) reduce the principal of, or interest on, the
Notes or any fees or other amounts payable hereunder, (d) postpone any date
fixed for any payment of principal of, or interest on, the Notes or any fees or
other amounts payable hereunder, (e) take action which requires the signing of
all the Banks pursuant to the terms of this Agreement, (f) change the
percentage of the Commitments or of the aggregate unpaid principal amount of
the Notes, or the number of Banks, which shall be required for the Banks or any
of them to take any action under this Agreement or any other Credit Document,
(g) release the Guarantor or otherwise change any obligation of the Guarantor
to pay any amount payable by the Guarantor hereunder or (h) amend this Section
10.01; provided, further, that no amendment, waiver or consent shall, unless in
writing and signed by the Agent in addition to the Banks required above to take
such action, affect the rights or duties of the Agent under any Credit
Document; and provided, further, that no amendment, waiver or consent shall,
unless in writing and signed by the Guarantor in addition to any other party
required above to take such action, affect the rights or duties of the
Guarantor under any Credit Document; and provided, further, that no increase
may be made with respect to any Bank's Commitment without the consent of such
Bank.

       Section 10.02.  Notices, Etc.  All notices and other communications
provided for hereunder shall be in writing (including telecopy, telegraphic,
telex or cable communication) and mailed, telecopied, telegraphed, telexed,
cabled or delivered, if to any Bank, as specified opposite its name on Schedule
I hereto or specified pursuant to an Assignment; if to the Borrower or the
Guarantor, as specified opposite its name on Schedule II hereto; and if to
NationsBank, as Agent, as specified opposite its name on Schedule I hereto or,
as to the Borrower, the Guarantor, or the Agent, at such other address as shall
be designated by such party in a written notice to the other parties and, as to
each other party, at such other address as shall be designated by such party in
a written notice to the Borrower, the Guarantor, and the Agent.  All such
notices and communications shall, when mailed, telecopied, telegraphed, telexed
or cabled, be effective when deposited in the mails, sent by telecopier to any
party to the telecopier number as set forth herein or on Schedule I or Schedule
II (or other telecopy number specified by such party in a written notice to the
other parties hereto), delivered to the telegraph company, telexed to any party
to the telex number set forth hereinabove or on Schedule I or Schedule II (or
other telex number designated by such party in a written notice to the other
parties hereto), confirmed by telex answerback, or delivered to the cable
company, respectively, except that notices and communications to the Agent
pursuant to Article II or IX shall not be effective until received by the
Agent.

       Section 10.03.  No Waiver; Remedies.  No failure on the part of any Bank
or the Agent to exercise, and no delay in exercising, any right under any
Credit Document shall operate as a waiver thereof; nor shall any single or
partial exercise of any such right preclude any other or further exercise
thereof or the exercise of any other right.  The remedies provided in the
Credit Documents are cumulative and not exclusive of any remedies provided by
law.





                                      -49-
<PAGE>   56
       Section 10.04.  Costs, Expenses and Taxes.

       (a) The Borrower agrees to pay on demand (i) all reasonable costs and
expenses of the Agent in connection with the preparation, execution, delivery,
administration, modification and amendment of any Credit Document, including,
without limitation, the reasonable fees and out-of-pocket expenses of counsel
for the Agent with respect thereto and with respect to advising the Agent as to
its rights and responsibilities under any Credit Document, Agent's out-of-
pocket expenses associated with the negotiation and closing and (ii) all costs
and expenses, if any (including, without limitation, reasonable counsel fees
and expenses, which may include inside counsel), of the Agent and each Bank in
connection with the enforcement (whether through negotiations, legal
proceedings or otherwise) against the Borrower or the Guarantor of any Credit
Document.

       (b)    THE BORROWER AGREES, TO THE FULLEST EXTENT PERMITTED BY LAW, TO
INDEMNIFY AND HOLD HARMLESS THE AGENT, EACH CO-AGENT, THE ARRANGER &
SYNDICATION AGENT AND EACH BANK AND EACH OF THEIR RESPECTIVE DIRECTORS,
OFFICERS, EMPLOYEES AND AGENTS FROM AND AGAINST ANY AND ALL CLAIMS, DAMAGES,
LIABILITIES AND EXPENSES (INCLUDING, WITHOUT LIMITATION, REASONABLE FEES AND
DISBURSEMENTS OF COUNSEL) FOR WHICH ANY OF THEM MAY BECOME LIABLE OR WHICH MAY
BE INCURRED BY OR ASSERTED AGAINST THE AGENT, SUCH CO-AGENT, THE ARRANGER &
SYNDICATION AGENT OR SUCH BANK OR ANY SUCH DIRECTOR, OFFICER, EMPLOYEE OR AGENT
(OTHER THAN BY ANOTHER BANK OR ANY SUCCESSOR OR ASSIGN OF ANOTHER BANK), IN
EACH CASE IN CONNECTION WITH OR ARISING OUT OF OR BY REASON OF ANY
INVESTIGATION, LITIGATION, OR PROCEEDING, WHETHER OR NOT THE AGENT, SUCH CO-
AGENT, THE ARRANGER & SYNDICATION AGENT OR SUCH BANK OR ANY SUCH DIRECTOR,
OFFICER, EMPLOYEE OR AGENT IS A PARTY THERETO, ARISING OUT OF, RELATED TO OR IN
CONNECTION WITH ANY CREDIT DOCUMENT OR ANY TRANSACTION IN WHICH ANY PROCEEDS OF
ALL OR ANY PART OF THE ADVANCES ARE APPLIED (OTHER THAN ANY SUCH CLAIM, DAMAGE,
LIABILITY OR EXPENSE TO THE EXTENT ATTRIBUTABLE TO THE GROSS NEGLIGENCE OR
WILLFUL MISCONDUCT OF, OR VIOLATION OF ANY LAW OR REGULATION BY, ANY SUCH
INDEMNIFIED PARTY).

       Section 10.05.  Right of Set-off.  Upon (i) the occurrence and during
the continuance of any Event of Default and (ii) the making of the request or
the granting of the consent specified by Section 8.01 to authorize the Agent to
declare the Notes due and payable pursuant to the provisions of Section 8.01,
each Bank is hereby authorized at any time and from time to time, to the
fullest extent permitted by law, to set off and apply any and all deposits
(general or special, time or demand, provisional or final) at any time held and
other indebtedness at any time owing by such Bank to or for the credit or the
account of the Borrower or the Guarantor against any and all of the obligations





                                      -50-
<PAGE>   57
of the Borrower or the Guarantor now or hereafter existing under the Credit
Documents, irrespective of whether or not such Bank shall have made any demand
under this Agreement or such Notes and although such obligations may be
unmatured.  Each Bank agrees promptly to notify the Borrower and the Guarantor
after such set-off and application made by such Bank, provided that the failure
to give such notice shall not affect the validity of such set-off and
application.  The rights of each Bank under this Section are in addition to
other rights and remedies (including, without limitation, other rights of
set-off) which such Bank may have.

       Section 10.06.  Bank Assignments and Participations.

       (a)    Assignments.  Any Bank may assign to one or more banks or other
entities all or any portion of its rights and obligations under this Agreement
(including, without limitation, all or a portion of its Commitment, the
Advances owing to it, and the Notes held by it); provided, however, that (i)
each such assignment of an Assigning Bank's Commitment shall be of a constant,
and not a varying, percentage of all of such Bank's rights and obligations
under this Agreement in respect of such Commitment and such Bank shall
simultaneously assign a pro rata portion of  such Bank's rights and obligations
in respect of its Parallel Agreement Commitment so that its pro rata percentage
of each of the Commitments and the Parallel Agreement Commitments is the same,
(ii) the amount of the resulting Commitment and Advances of the assigning Bank
(unless it is assigning all its Commitment and all of its Parallel Agreement
Commitment) and the assignee Bank pursuant to each such assignment (determined
as of the date of the Assignment with respect to such assignment) shall in no
event be less than $10,000,000 and shall be an integral multiple of $1,000,000,
(iii) each such assignment shall be to an Eligible Assignee, (iv) the parties
to each such assignment shall execute and deliver to the Agent, for its
acceptance and recording in the Register, an Assignment, together with the Note
or Notes subject to such assignment, and (v) each Eligible Assignee not already
a Bank hereunder shall pay to the Agent an assignment fee of $3000 in
connection with such assignment. Upon such execution, delivery, acceptance and
recording, from and after the effective date specified in each Assignment,
which effective date shall be at least three Business Days after the execution
thereof, (A) the assignee thereunder shall be a party hereto for all purposes
and, to the extent that rights and obligations hereunder have been assigned to
it pursuant to such Assignment, have the rights and obligations of a Bank
hereunder and (B) such Bank thereunder shall, to the extent that rights and
obligations hereunder have been assigned by it pursuant to such Assignment,
relinquish its rights and be released from its obligations under this Agreement
(and, in the case of an Assignment covering all or the remaining portion of
such Bank's rights and obligations under this Agreement, such Bank shall cease
to be a party hereto).

       (b)    Terms of Assignments.  By executing and delivering an Assignment,
the Bank thereunder and the assignee thereunder confirm to and agree with each
other and the other parties hereto the matters set forth in paragraphs 2 and 3
of such Assignment.





                                      -51-
<PAGE>   58
       (c)    The Register.  The Agent shall maintain at its address referred
to on Schedule I a copy of each Assignment delivered to and accepted by it and
a register for the recordation of the names and addresses of the Banks and the
Commitments of, and principal amount of the Advances owing to, each Bank from
time to time (the "Register").  The entries in the Register shall be conclusive
and binding for all purposes, absent manifest error, and the Borrower, the
Guarantor, the Agent, and the Banks may treat each Person whose name is
recorded in the Register as a Bank hereunder for all purposes of this
Agreement.  The Register shall be available for inspection by the Borrower, the
Guarantor, or any Bank at any reasonable time and from time to time upon
reasonable prior notice.

       (d)    Procedures.  Upon its receipt of an Assignment executed by a Bank
and an Eligible Assignee, together with the Note or Notes subject to such
assignment, the Agent shall, if such Assignment has been completed and is in
substantially the form of the attached Exhibit C, (i) accept such Assignment,
(ii) record the information contained therein in the Register, and (iii) give
prompt notice thereof to the Borrower and the Guarantor.  Within five Business
Days after its receipt of such notice, the Borrower, at its own expense, shall
execute and deliver to the Agent (x) in exchange for the surrendered A Note, a
new A Note to the order of such Eligible Assignee in an amount equal to the
Commitment assumed by it pursuant to such Assignment (without giving affect to
any B Reduction) and, if such assigning Bank has retained any Commitment
hereunder, a new A Note to the order of such Bank in an amount equal to the
Commitment retained by it hereunder (without giving affect to any B Reduction),
and (y) in exchange for any surrendered B Note, a new B Note to the order of
such Eligible Assignee in an amount equal to the B Advances assumed by it
pursuant to such Assignment and, if such assigning Bank has retained any B
Advances hereunder, a new B Note to the order of such Bank in any amount equal
to the B Advances retained by it hereunder.  Such new A Notes and B Notes shall
be dated the effective date of such Assignment and shall otherwise be in
substantially the form of the attached Exhibit A-1 or Exhibit A-2, as the case
may be.

       (e)    Participations.  Each Bank may sell participations to one or more
banks or other entities in or to all or a portion of its rights and obligations
under this Agreement (including, without limitation, all or a portion of its
Commitment, the Advances owing to it, and the Notes held by it); provided,
however, that (i) such Bank's obligations under this Agreement (including,
without limitation, its Commitment to the Borrower hereunder) shall remain
unchanged, (ii) such Bank shall remain solely responsible to the other parties
hereto for the performance of such obligations, (iii) such Bank shall remain
the holder of any such Notes for all purposes of this Agreement, (iv) the
Borrower, the Guarantor, the Agent, and the other Banks shall continue to deal
solely and directly with such Bank in connection with such Bank's rights and
obligations under this Agreement, (v) such Bank shall not require the
participant's consent to any matter under this Agreement, except for changes in
the principal amount of such Bank's Commitment, any Note payable to such Bank
in which the participant has an interest, or the aggregate Commitments,
reductions in fees or interest, the date any amount is due hereunder, or
extending the Termination Date or continuing the Commitment of such Bank
pursuant to Section 2.15 hereof, and (vi) such Bank shall give prompt





                                      -52-
<PAGE>   59
notice to the Borrower of each such participation sold by such Bank.  The
Borrower hereby agrees that participants shall have the same rights under
Sections 2.06(c), 2.10, 2.11, and 10.04 hereof as the Bank to the extent of
their respective participations.

       (f)  Assignment to Federal Reserve Bank.  Notwithstanding the
limitations set forth in paragraph (a) of this Section, any Bank may at any
time assign all or any portion of its rights under this Agreement or any Notes
payable to such Bank to a Federal Reserve Bank without the prior written
consent of the Borrower, the Guarantor, the Agent, the Co-Agents, or the
Arranger & Syndication Agent, provided that no such assignment shall release
such assigning Bank from any of its obligations hereunder or substitute any
such Federal Reserve Bank for such Bank as a party hereto.

       Section 10.07.  Governing Law.  This Agreement, the Notes and the other
Credit Documents shall be governed by, and construed in accordance with, the
laws of the State of Texas.

       Section 10.08.  Interest.

       (a)    It is the intention of the parties hereto that the Agent and each
Bank shall conform strictly to usury laws applicable to it, if any.
Accordingly, if the transactions with the Agent or any Bank contemplated hereby
would be usurious under applicable law, if any, then, in that event,
notwithstanding anything to the contrary in this Agreement, the Notes, or any
other agreement entered into in connection with or as security for this
Agreement or the Notes, it is agreed as follows:  (i) the aggregate of all
consideration which constitutes interest under applicable law that is
contracted for, taken, reserved, charged or received by the Agent or such Bank,
as the case may be, under this Agreement, the Notes, or under any other
agreement entered into in connection with or as security for this Agreement or
the Notes shall under no circumstances exceed the maximum amount allowed by
such applicable law and any excess shall be cancelled automatically and, if
theretofore paid, shall at the option of the Agent or such Bank, as the case
may be, be credited by the Agent or such Bank, as the case may be, on the
principal amount of the obligations owed to the Agent or such Bank, as the case
may be, by the Borrower or refunded by the Agent or such Bank, as the case may
be, to the Borrower, and (ii) in the event that the maturity of any Note or
other obligation payable to the Agent or such Bank, as the case may be, is
accelerated or in the event of any required or permitted prepayment, then such
consideration that constitutes interest under law applicable to the Agent or
such Bank, as the case may be, may never include more than the maximum amount
allowed by such applicable law and excess interest, if any, to the Agent or
such Bank, as the case may be, provided for in this Agreement or otherwise
shall be cancelled automatically as of the date of such acceleration or
prepayment and, if theretofore paid, shall, at the option of the Agent or such
Bank, as the case may be, be credited by the Agent or such Bank, as the case
may be, on the principal amount of the obligations owed to the Agent or such
Bank, as the case may be, by the Borrower or refunded by the Agent or such
Bank, as the case may be, to the Borrower.  To the extent that any Bank may be
subject to Texas law limiting the amount of interest





                                      -53-
<PAGE>   60
payable for its account, such Bank shall utilize the indicated (weekly) rate
ceiling from time to time in effect as provided in Article 5069-1.04 of the
Revised Civil Statutes of Texas, as amended.

       (b)    In the event that at any time the interest rate applicable to any
Advance made by any Bank would exceed the maximum non-usurious rate allowed by
applicable law, the rate of interest to accrue on the Advances by such Bank
shall be limited to the maximum non-usurious rate allowed by applicable law,
but shall accrue, to the extent permitted by law, on the principal amount of
the Advances made by such Bank from time to time outstanding, if any, at the
maximum non-usurious rate allowed by applicable law until the total amount of
interest accrued on the Advances made by such Bank equals the amount of
interest which would have accrued if the interest rates applicable to the
Advances pursuant to Article II had at all times been in effect.  In the event
that upon the final payment of the Advances made by any Bank and termination of
the Commitment of such Bank, the total amount of interest paid to such Bank
hereunder and under the Notes is less than the total amount of interest which
would have accrued if the interest rates applicable to such Advances pursuant
to Article II had at all times been in effect, then the Borrower agrees to pay
to such Bank, to the extent permitted by law, an amount equal to the excess of
(a) the lesser of (i) the amount of interest which would have accrued on such
Advances if the maximum non-usurious rate allowed by applicable law had at all
times been in effect or (ii) the amount of interest rates applicable to such
Advances pursuant to Article II had at all times been in effect over (b) the
amount of interest otherwise accrued on such Advances in accordance with this
Agreement.

       Section 10.09.  Execution in Counterparts.  This Agreement may be
executed in any number of counterparts and by different parties hereto in
separate counterparts, each of which when so executed shall be deemed to be an
original and all of which taken together shall constitute one and the same
agreement.

       Section 10.10.  Survival of Agreements, Representations and Warranties,
Etc.  All warranties, representations and covenants made by the Borrower or the
Guarantor or any officer of the Borrower or the Guarantor herein or in any
certificate or other document delivered in connection with this Agreement shall
be considered to have been relied upon by the Banks and shall survive the
issuance and delivery of the Notes and the making of the Advances regardless of
any investigation.  Theindemnities and other obligations of the Borrower
contained in this Agreement, and the indemnities by the Banks in favor of the
Agent and its officers, directors, employees and agents, will survive the
repayment of the Advances and the termination of this Agreement.

       Section 10.11.  Borrower's Right to Apply Deposits.  In the event that
any Bank is placed in receivership or enters a similar proceeding, the Borrower
may, to the full extent permitted by law, make any payment due to such Bank
hereunder, to the extent of finally collected unrestricted deposits of the
Borrower in U.S. dollars held by such Bank, by giving notice to the Agent and
such Bank directing such Bank to apply such deposits to such indebtedness.  If
the amount of such





                                      -54-
<PAGE>   61
deposits is insufficient to pay such indebtedness then due and owing in full,
the Borrower shall pay the balance of such insufficiency in accordance with
this Agreement.

       Section 10.12.  Confidentiality.  Each Bank agrees that it will use best
efforts, to the extent not inconsistent with practical business requirements,
not to disclose without the prior consent of the Borrower and the Guarantor
(other than to employees, auditors, accountants, counsel or other professional
advisors of the Agent or any Bank or any Bank's Affiliate) any information with
respect to the Borrower or the Guarantor or their Subsidiaries which is
furnished pursuant to this Agreement and which (i) the Borrower or the
Guarantor in good faith consider to be confidential and (ii) is either clearly
marked confidential or is designated by the Borrower or the Guarantor to the
Agent or the Banks in writing as confidential, provided that any Bank may
disclose any such information (a) as has become generally available to the
public, (b) as may be required or appropriate in any report, statement or
testimony submitted to or required by any municipal, state or Federal
regulatory body having or claiming to have jurisdiction over such Bank or
submitted to or required by the Board of Governors of the Federal Reserve
System or the Federal Deposit Insurance Corporation or similar organizations
(whether in the United States or elsewhere) or their successors, (c) as may be
required or appropriate in response to any summons or subpoena in connection
with any litigation, (d) in order to comply with any law, order, regulation or
ruling applicable to such Bank, (e) to the prospective assignee or participant
in connection with any contemplated transfer of any of the Notes or any
interest therein by such Bank, provided that such prospective assignee or
participant executes an agreement with or for the benefit of the Borrower and
the Guarantor containing provisions substantially identical to those contained
in this Section 10.12.

       Section 10.13.  Binding Effect.  This Agreement shall become effective
when it shall have been executed by the Borrower, the Guarantor and the Agent,
and when each Bank listed on the signature pages hereof has delivered an
executed counterpart hereof to the Agent, has sent to the Agent a facsimile
copy of its signature hereon or has notified the Agent that such Bank has
executed this Agreement and thereafter shall be binding upon and inure to the
benefit of the Borrower, the Guarantor, the Agent, each Bank and their
respective successors and assigns, except that the Borrower and the Guarantor
shall not have the right to assign any of their respective rights hereunder or
any interest herein without the prior written consent of the Banks.

       SECTION 10.14.  ENTIRE AGREEMENT.  PURSUANT TO SECTION 26.02 OF THE
TEXAS BUSINESS AND COMMERCE CODE, A LOAN AGREEMENT IN WHICH THE AMOUNT INVOLVED
IN THE LOAN AGREEMENT EXCEEDS $50,000 IN VALUE IS NOT ENFORCEABLE UNLESS THE
LOAN AGREEMENT IS IN WRITING AND SIGNED BY THE PARTY TO BE BOUND OR THAT
PARTY'S AUTHORIZED REPRESENTATIVE.

       THE RIGHTS AND OBLIGATIONS OF THE PARTIES TO AN AGREEMENT SUBJECT TO THE
PRECEDING PARAGRAPH SHALL BE DETERMINED SOLELY





                                      -55-
<PAGE>   62
FROM THE WRITTEN LOAN AGREEMENT, AND ANY PRIOR ORAL AGREEMENTS BETWEEN THE
PARTIES ARE SUPERSEDED BY AND MERGED INTO THE LOAN AGREEMENT.  THIS WRITTEN
AGREEMENT AND THE CREDIT DOCUMENTS, AS DEFINED IN THIS AGREEMENT, REPRESENT THE
FINAL AGREEMENT AMONG THE PARTIES AND MAY NOT BE CONTRADICTED BY EVIDENCE OF
PRIOR, CONTEMPORANEOUS, OR SUBSEQUENT ORAL AGREEMENTS OF THE PARTIES.

       Section 10.15.  Severability.  In the event that any one or more of the
provisions contained in this Agreement or in any other Credit Document should
be held invalid, illegal or unenforceable in any respect, the validity,
legality and enforceability of the remaining provisions contained herein and
therein shall not in any way be affected or impaired thereby.


                    [REMAINDER OF PAGE INTENTIONALLY BLANK]





                                      -56-
<PAGE>   63
       IN WITNESS WHEREOF, the parties hereto have caused this Agreement to be
executed by their respective officers thereunto duly authorized, as of the date
first above written.


                                           BORROWER:
                                           -------- 

                                           FINA OIL AND CHEMICAL COMPANY



                                                                             
                                           ----------------------------------
                                           Yves Bercy
                                           Vice President & Chief
                                             Financial Officer


                                           GUARANTOR:
                                           --------- 

                                           FINA, INC.



                                                                             
                                           ----------------------------------
                                           Yves Bercy
                                           Vice President & Chief
                                             Financial Officer


                                           AGENT:
                                           ----- 

                                           NATIONSBANK OF TEXAS, N.A.,
                                            as Agent



                                                                              
                                           -----------------------------------
                                           Denise Ashford Smith
                                           Senior Vice President





                                      -57-
<PAGE>   64

                                           ARRANGER & SYNDICATION AGENT
                                           ----------------------------

                                           NATIONSBANC CAPITAL MARKETS, INC.



                                           ----------------------------------
                                           David E. Hunt
                                           Managing Director


COMMITMENTS:                       BANKS:
-----------                        ----- 


$9,411,766                                 NATIONSBANK OF TEXAS, N.A.



                                           ----------------------------------
                                           Denise Ashford Smith
                                           Senior Vice President


$8,117,647                                 CIBC INC.



                                           ----------------------------------
                                           By:
                                              -------------------------------
                                           Title:
                                                 ----------------------------

$8,117,647                                 TEXAS COMMERCE BANK
                                           NATIONAL ASSOCIATION



                                           ----------------------------------
                                           By:
                                              -------------------------------
                                           Title:
                                                 ----------------------------





                                      -58-
<PAGE>   65
$5,764,706                                 BANK BRUSSELS LAMBERT,
                                           NEW YORK BRANCH



                                           ----------------------------------
                                           By:
                                              -------------------------------
                                           Title:
                                                 ----------------------------


$5,764,706                                 BANQUE NATIONALE DE PARIS,
                                           HOUSTON AGENCY


                                           ----------------------------------
                                           By:
                                              -------------------------------
                                           Title:
                                                 ----------------------------


$5,764,706                                 CREDIT LYONNAIS NEW YORK BRANCH



                                           ----------------------------------
                                           By:
                                              -------------------------------
                                           Title:
                                                 ----------------------------


$5,764,706                                 THE FUJI BANK, LIMITED
                                           HOUSTON AGENCY



                                           ----------------------------------
                                           By:
                                              -------------------------------
                                           Title:
                                                 ----------------------------





                                      -59-
<PAGE>   66
$5,764,706                                 MELLON BANK, N.A.



                                           ----------------------------------
                                           By:
                                              -------------------------------
                                           Title:
                                                 ----------------------------


$5,764,706                                 SOCIETE GENERALE, SOUTHWEST
                                           AGENCY



                                           ----------------------------------
                                           By:
                                              -------------------------------
                                           Title:
                                                 ----------------------------


$5,764,706                                 THE SUMITOMO BANK, LIMITED



                                           ----------------------------------
                                           By:
                                              -------------------------------
                                           Title:
                                                 ----------------------------


$5,764,706                                 UNION BANK OF SWITZERLAND,
                                           HOUSTON AGENCY



                                           ----------------------------------
                                           By:
                                              -------------------------------
                                           Title:
                                                 ----------------------------


                                           ----------------------------------
                                           By:
                                              -------------------------------
                                           Title:
                                                 ----------------------------





                                      -60-
<PAGE>   67
$4,705,882                                 BAYERISCHE LANDESBANK GIROZENTRALE,
                                           CAYMAN ISLANDS BRANCH


                                           ----------------------------------
                                           By:
                                              -------------------------------
                                           Title:
                                                 ----------------------------


                                           ----------------------------------
                                           By:
                                              -------------------------------
                                           Title:
                                                 ----------------------------


$4,705,882                                 CITICORP USA, INC.



                                           ----------------------------------
                                           By:
                                              -------------------------------
                                           Title:
                                                 ----------------------------


$4,705,882                                 CREDIT COMMERCIAL DE FRANCE



                                           ----------------------------------
                                           By:
                                              -------------------------------
                                           Title:
                                                 ----------------------------


                                           ----------------------------------
                                           By:
                                              -------------------------------
                                           Title:
                                                 ----------------------------





                                      -61-
<PAGE>   68
$4,705,882                                 THE DAI-ICHI KANGYO BANK, LTD.
                                           NEW YORK BRANCH



                                           ----------------------------------
                                           By:
                                              -------------------------------
                                           Title:
                                                 ----------------------------


$4,705,882                                 DEN DANSKE BANK AKTIESELSKAB
                                           CAYMAN ISLANDS BRANCH



                                           ----------------------------------
                                           By:
                                              -------------------------------
                                           Title:
                                                 ----------------------------



                                           ----------------------------------
                                           By:
                                              -------------------------------
                                           Title:
                                                 ----------------------------


$4,705,882                                 GENERALE BANK--NEW YORK BRANCH



                                           ----------------------------------
                                           By:
                                              -------------------------------
                                           Title:
                                                 ----------------------------


============
$100,000,000                               TOTAL COMMITMENTS





                                      -62-
<PAGE>   69
                                  EXHIBIT A-1

                               A PROMISSORY NOTE


U.S. $___________________                          Dated as of February 27, 1997


       FOR VALUE RECEIVED, the undersigned, Fina Oil and Chemical Company, a
Delaware corporation (the "Borrower"), HEREBY PROMISES TO PAY to the order of
__________________________ (the "Bank"), for the account of its Applicable
Lending Office (as defined in the Credit Agreement referred to below) or any
other office designated by the Bank the principal amount of each A Advance (as
defined below) made by the Bank to the Borrower pursuant to the Credit
Agreement (as defined below) on the date such A Advance is due and payable as
set forth in the Credit Agreement.

       The Borrower promises to pay interest on the unpaid principal amount of
each A Advance from the date of such A Advance until such principal amount is
paid in full, at such interest rates, and payable at such times, as are
specified in the Credit Agreement.

       Both principal and interest are payable in lawful money of the United
States of America to NationsBank of Texas, N.A., as Agent, at 901 Main Street,
Dallas, Texas 75202, in same day funds.  Each A Advance made by the Bank to the
Borrower and the maturity thereof, and all payments made on account of
principal thereof, shall be recorded by the Bank and, prior to any transfer
hereof, endorsed on the grid attached hereto which is part of this Promissory
Note.

       This Promissory Note is one of the A Notes referred to in, and is
subject to and entitled to the benefits of, the U.S.$100,000,000 364-Day Credit
Agreement dated as of February 27, 1997 (as it may be amended from time to time
in accordance with its terms, the "Credit Agreement") among the Borrower, Fina,
Inc., as Guarantor, the Bank, certain other banks parties thereto, CIBC Inc.
and Texas Commerce Bank National Association, as Co-Agents, NationsBanc Capital
Markets, Inc., as Arranger & Syndication Agent, and NationsBank of Texas, N.A.,
as Agent for the Bank and such other banks.  The Credit Agreement, among other
things, (i) provides for the making of advances (the "A Advances") by the Bank
to the Borrower from time to time pursuant to Section 2.01 of the Credit
Agreement in an aggregate outstanding amount not to exceed at any time the U.S.
dollar amount first above mentioned, the indebtedness of the Borrower resulting
from each such A Advance being evidenced by this Promissory Note, and (ii)
contains provisions for acceleration of the maturity hereof upon the happening
of certain stated events and also for prepayments on account of principal
hereof prior to the maturity hereof upon the terms and conditions therein
specified.  Capitalized terms used herein which are not defined herein and are
defined in the Credit Agreement are used herein as therein defined.
<PAGE>   70
       The Borrower hereby waives presentment, demand, protest, notice of
intent to accelerate, notice of acceleration and any other notice of any kind,
except as provided in the Credit Agreement.  No failure to exercise, and no
delay in exercising, any rights hereunder on the part of the holder hereof
shall operate as a waiver of such rights.

       This Promissory Note shall be governed by, and construed in accordance
with, the laws of the State of Texas (except that Tex. Rev. Civ. Stat. Ann.
Art. 5069, Ch. 15, which regulates certain revolving credit loan accounts,
shall not apply to this Note).


                                           FINA OIL AND CHEMICAL COMPANY


                                           ------------------------------
                                           By:
                                              ---------------------------
                                           Title:
                                                 ------------------------



                                     -2-
<PAGE>   71
                                  EXHIBIT A-2


                               B PROMISSORY NOTE


U.S. $_______________                                   Dated:  __________, 19__



       FOR VALUE RECEIVED, the undersigned, Fina Oil and Chemical Company, a
Delaware corporation (the "Borrower"), HEREBY PROMISES TO PAY to the order of
__________________________ (the "Bank") for the account of its Applicable
Lending Office (as defined in the Credit Agreement referred to below), on
___________, 199_, the principal amount of ____________________ Dollars
($__________).

       The Borrower promises to pay interest on the unpaid principal amount
hereof from the date hereof until such principal amount is paid in full, at the
interest rate and payable on the interest payment date or dates provided below:

       Interest Rate: _____% per annum (calculated on the basis of a year of
       ____ days for the actual number of days elapsed).

       Interest Payment Date or Dates: ______________________

       Both principal and interest are payable in lawful money of the United
States of America to NationsBank of Texas, N.A., as Agent, at 901 Main Street,
Dallas, Texas 75202, in same day funds.

       This Promissory Note is one of the B Notes referred to in, and is
entitled to the benefits of, the U.S. $100,000,000 364-Day Credit Agreement
dated as of February 27, 1997 (as it may be amended from time to time in
accordance with its terms, the "Credit Agreement") among the Borrower, Fina,
Inc., as Guarantor, the Bank, certain other banks parties thereto, CIBC Inc.
and Texas Commerce Bank National Association, as Co-Agents, NationsBanc Capital
Markets, Inc., as Arranger & Syndication Agent, and NationsBank of Texas, N.A.,
as Agent for the Bank and such other banks.  The Credit Agreement, among other
things, contains provisions for acceleration of the maturity hereof upon the
happening of certain stated events.  Capitalized terms used herein which are
not defined herein and are defined in the Credit Agreement are used herein as
therein defined.

       The Borrower hereby waives presentment, demand, protest, notice of
intent to accelerate, notice of acceleration and any other notice of any kind,
except as provided in the Credit Agreement.





<PAGE>   72
No failure to exercise, and no delay in exercising, any rights hereunder on the
part of the holder hereof shall operate as a waiver of such rights.

       This Promissory Note shall be governed by, and construed in accordance
with, the laws of the State of Texas.



                                           FINA OIL AND CHEMICAL COMPANY


                                           ------------------------------
                                           By:
                                              ---------------------------
                                           Title:
                                                 ------------------------





                                      -2-
<PAGE>   73


                                  EXHIBIT B-1

                             NOTICE OF A BORROWING


                                     [Date]


NationsBank of Texas, N.A., as Agent
 for the Banks parties
 to the Credit Agreement
 referred to below
901 Main Street, 64th Floor
Dallas, Texas 75202

Attention:  Ms. Denise Ashford Smith

Ladies and Gentlemen:

       The undersigned, Fina Oil and Chemical Company (the "Borrower"), refers
to the U.S.  $100,000,000 364-Day Credit Agreement dated as of February 27,
1997 (as it may be amended from time to time in accordance with its terms, the
"Credit Agreement"; the terms defined therein and not defined herein being used
herein as therein defined), among the undersigned, Fina, Inc., certain Banks
parties thereto, CIBC Inc. and Texas Commerce Bank National Association, as Co-
Agents, NationsBanc Capital Markets, Inc., as Arranger & Syndication Agent, and
NationsBank of Texas, N.A., as Agent for such Banks, and hereby gives you
notice, irrevocably, pursuant to Section 2.02 of the Credit Agreement that the
undersigned hereby requests an A Borrowing under the Credit Agreement, and in
that connection sets forth below the information relating to such A Borrowing
(the "Proposed A Borrowing") as required by Section 2.02(a) of the Credit
Agreement:

       (i)    The Business Day of the Proposed A Borrowing is ________________,
              19___.

       (ii)   The Type of A Advances comprising the Proposed A Borrowing is
              [Base Rate Advances][Eurodollar Rate Advances].

       (iii)  The aggregate amount of the Proposed A Borrowing is
              $____________.





<PAGE>   74
       (iv)   The Interest Period for each A Advance made as part of the
              Proposed A Borrowing is _______ [days] [months].

       The undersigned hereby certifies that the following statements are true
on the date hereof, and will be true on the date of the Proposed A Borrowing:

              (a)    the representations and warranties contained in Article V
       of the Credit Agreement (excluding those contained in Section 5.05 and
       Section 5.06 of the Credit Agreement) are correct on and as of the date
       of the Proposed A Borrowing, before and after giving effect to the
       Proposed A Borrowing and to the application of the proceeds therefrom,
       as though made on and as of such date;

              (b)    no event has occurred and is continuing, or would result
       from the Proposed A Borrowing or from the application of the proceeds
       therefrom, which constitutes an Event of Default *[or which would
       constitute a Default]; and

              (c)    after giving effect to the Proposed A Borrowing and all
       other Borrowings which have been requested on or prior to the date of
       the Proposed A Borrowing but which have not been made prior to such
       date, the aggregate principal amount of all Borrowings will not exceed
       the aggregate of the Commitments.


                                           Very truly yours,

                                           FINA OIL AND CHEMICAL COMPANY


                                           ------------------------------
                                           By:
                                              ---------------------------
                                           Title:
                                                 ------------------------





--------------------

     *To be included in Notices of A Borrowing in respect of A Borrowings
referred to in Section 3.03 of the Credit Agreement.





                                      -2-
<PAGE>   75
                                  EXHIBIT B-2

                             NOTICE OF B BORROWING



                                     [Date]


NationsBank of Texas, N.A., as Agent
 for the Banks parties
 to the Credit Agreement
 referred to below
901 Main Street, 64th Floor
Dallas, Texas 75202

Attention:  Ms. Denise Ashford Smith

Ladies and Gentlemen:

       The undersigned, Fina Oil and Chemical Company (the "Borrower"), refers
to the U.S. $100,000,000 364-Day Credit Agreement dated as of February 27, 1997
(as it may be amended from time to time in accordance with its terms, the
"Credit Agreement"; the terms defined therein and not defined herein being used
herein as therein defined), among the undersigned, Fina, Inc., certain Banks
parties thereto, CIBC Inc. and Texas Commerce Bank National Association, as Co-
Agents, NationsBanc Capital Markets, Inc., as Arranger & Syndication Agent, and
NationsBank of Texas, N.A., as Agent for such Banks, and hereby gives you
notice, irrevocably, pursuant to Section 2.16 of the Credit Agreement that the
undersigned hereby requests a B Borrowing under the Credit Agreement, and in
that connection sets forth the terms on which such B Borrowing (the "Proposed B
Borrowing") is requested to be made:

      (A)     Date of B Borrowing          ________________________
      (B)     Amount of B Borrowing        ________________________
      (C)     Maturity Date                ________________________
      (D)     Interest Rate Basis          ________________________
      (E)     Interest Payment Date(s)     ________________________
      (F)     ____________________         ________________________
      (G)     ____________________         ________________________





<PAGE>   76
       The undersigned hereby certifies that the following statements are true
on the date hereof, and will be true on the date of the Proposed B Borrowing:

              (a)    the representations and warranties contained in Article V
       of the Credit Agreement (excluding those contained in Section 5.05 and
       Section 5.06 of the Credit Agreement) are correct on and as of the date
       of the Proposed B Borrowing, before and after giving effect to the
       Proposed B Borrowing and to the application of the proceeds therefrom,
       as though made on and as of such date;

              (b)    no event has occurred and is continuing, or would result
       from the Proposed B Borrowing or from the application of the proceeds
       therefrom, which constitutes a Default; and

              (c)    following the making of the Proposed B Borrowing and all
       other Borrowings to be made on the same day under the Credit Agreement,
       the aggregate principal amount of all Advances then outstanding shall
       not exceed the aggregate amount of the Commitments (computed without
       regard to any B Reduction).

       The undersigned hereby confirms that the Proposed B Borrowing is to be
made available to it in accordance with Section 2.08(a)(v) of the Credit
Agreement.



                                           Very truly yours,

                                           FINA OIL AND CHEMICAL COMPANY



                                           ------------------------------
                                           By:
                                              ---------------------------
                                           Title:
                                                 ------------------------





                                      -2-
<PAGE>   77
                                   EXHIBIT C

                           ASSIGNMENT AND ACCEPTANCE

                          Dated ________________, 19__


       Reference is made to the U.S.$100,000,000 364-Day Credit Agreement dated
as of February 27, 1997 (as the same may be amended or modified from time to
time, the "Credit Agreement") among Fina Oil and Chemical Company, a Delaware
corporation (the "Borrower"), Fina, Inc., a Delaware corporation (the
"Guarantor"), the Banks, CIBC Inc. and Texas Commerce Bank National
Association, as Co-Agents, NationsBanc Capital Markets, Inc., as Arranger &
Syndication Agent, and NationsBank of Texas, N.A., as Agent.  Capitalized terms
not otherwise defined in this Assignment and Acceptance ("Assignment") shall
have the meanings assigned to them in the Credit Agreement.

       Pursuant to the terms of the Credit Agreement, ________________ wishes
to assign and delegate [(a)] ____%(1) of its rights and obligations under the
Credit Agreement in connection with its Commitment and its outstanding A
Advances and A Note [and (b) ____% of its rights under the Credit Agreement in
connection with its outstanding B Advance(s) and B Note(s)].  Therefore,
_________________ ("Assignor"), _______________ ("Assignee"), and the Agent
agree as follows:

       i.            The Assignor hereby sells and assigns and delegates to the
              Assignee, and the Assignee hereby purchases and assumes from the
              Assignor, as of the Effective Date (as defined below), without
              recourse to the Assignor and without representation or warranty
              except for the representations and warranties specifically set
              forth in clauses (i), (ii), and (iii) of Section 2 hereof, [(a)]
              a ___% interest in and to all of the Assignor's rights and
              obligations under the Credit Agreement in connection with its
              Commitment (without regard to any B Reduction), its outstanding A
              Advances and its A Note, [and (b) ____% of its rights under the
              Credit Agreement in connection with its outstanding B Advance(s)
              and B Note(s)].
          
       ii.           The Assignor (i) represents and warrants that, prior to
              executing this Assignment and Acceptance, its Commitment (without
              regard to any B Reduction) is $_____________, and the aggregate
              outstanding principal amount of A Advances owed to it by the
              Borrower is $_____________;





-------------------------

(1) Specify percentage in no more than 5 decimal points.

<PAGE>   78
              (ii) represents and warrants that it is the legal and beneficial
              owner of the interest being assigned by it hereunder and that
              such interest is free and clear of any adverse claim; (iii) makes
              no representation or warranty and assumes no responsibility with
              respect to any statements, warranties, or representations made in
              or in connection with the Credit Agreement or any other Credit
              Document or the execution, legality, validity, enforceability,
              genuineness, sufficiency, or value of the Credit Agreement or any
              other Credit Document or any other instrument or document
              furnished pursuant thereto; (iv) makes no representation or
              warranty and assumes no responsibility with respect to the
              financial condition of the Borrower or the Guarantor or the
              performance or observance by the Borrower or the Guarantor of any
              of their respective obligations under the Credit Agreement or any
              other Credit Document or any other instrument or document
              furnished pursuant thereto; and (v) attaches the Note(s) referred
              to in paragraph 1 above and requests that the Agent [(i)]
              exchange such A Note for [a] new A Note dated ____________, 19__
              in the principal amount of $______________ payable to the order
              of the Assignee[, and a new A Note dated _____________, 19___ in
              the principal amount of $__________ payable to the order of
              Assignor][, and (ii) exchange such B Note(s) for new B Note(s)
              dated __________, 19__ in the principal amount(s) of $__________,
              $__________, and $__________ payable to the order of the Assignee
              and new B Note(s) dated __________, 19__ in the principal
              amount(s) of $__________, $__________, and $__________].

      iii.           The Assignee (i) confirms that it has received a copy of
              the Credit Agreement, together with copies of the financial
              statements referred to in Section 5.05 thereof and such other
              documents and information as it has deemed appropriate to make
              its own credit analysis and decision to enter into this
              Assignment; (ii) agrees that it will, independently and without
              reliance upon the Agent, the Assignor, or any other Bank and
              based on such documents and information as it shall deem
              appropriate at the time, continue to make its own credit
              decisions in taking or not taking action under the Credit
              Agreement; (iii) appoints and authorizes the Agent to take such
              action as agent on its behalf and to exercise such powers under
              the Credit Agreement as are delegated to the Agent by the terms
              thereof, together with such powers as are reasonably incidental
              thereto; (iv) agrees that it will perform in accordance with
              their terms all of the obligations which by the terms of the
              Credit Agreement are required to be performed by it as a Bank;
              (v) specifies as its Domestic Lending Office (and address for
              notices) and Eurodollar Lending Office the offices set forth
              beneath its name on the





                                      -2-
<PAGE>   79
              signature pages hereof; (vi) attaches the forms prescribed by the
              Internal Revenue Service of the United States certifying as to
              the Assignee's status for purposes of determining exemption from
              United States withholding taxes with respect to all payments to
              be made to the Assignee under the Credit Agreement and its
              Note(s) or such other documents as are necessary to indicate that
              all such payments are subject to such rates at a rate reduced by
              an applicable tax treaty(2), and (vii) represents that it is an
              Eligible Assignee.

      iv.            The effective date for this Assignment and Acceptance
              shall be ________________ (the "Effective Date")(3) and
              following the execution of this Assignment, the Agent will record
              it.
          
      v.             Upon such recording, and as of the Effective Date, (i) the
              Assignee shall be a party to the Credit Agreement for all
              purposes, and, to the extent provided in this Assignment, have
              the rights and obligations of a Bank thereunder and (ii) the
              Assignor shall, to the extent provided in this Assignment,
              relinquish its rights (other than rights against the Borrower
              pursuant to Section 10.04 of the Credit Agreement, which shall
              survive this assignment) and be released from its obligations
              under the Credit Agreement.
          
      vi.            Upon such recording, from and after the Effective Date,
              the Agent shall make all payments under the Credit Agreement and
              the Note(s) in respect of the interest assigned hereby
              (including, without limitation, all payments of principal,
              interest, and fees) to the Assignee.  The Assignor and Assignee
              shall make all appropriate adjustments in payments under the
              Credit Agreement and the Note(s) for periods prior to the
              Effective Date directly between themselves.
          
      vii.           This Assignment shall be governed by, and construed and
              enforced in accordance with, the laws of the State of Texas.





--------------------

  (2) If the Assignee is organized under the laws of a jurisdiction outside the
      United States.

  (3) See Section 10.06(a).  Such date shall be at least three Business Days
      after the execution of this Assignment.

                                      -3-
<PAGE>   80
       The parties hereto have caused this Assignment to be duly executed as of
the date first above written.


                                   [ASSIGNOR]



                                   By:
                                      ----------------------------
                                   Name:
                                        --------------------------
                                   Title:
                                         -------------------------

                                   Address:
                                           -----------------------
                                           
                                           -----------------------

                                           -----------------------

                                   Attention:     
                                             ---------------------
                                   Telecopy: 
                                             ---------------------
                                   Telephone:
                                             ---------------------

                                   [ASSIGNEE]
                                   Domestic Lending Office:
                                   ----------------------- 

                                   By:
                                      ----------------------------
                                   Name:
                                        --------------------------
                                   Title:
                                         -------------------------

                                   Address:
                                           -----------------------
                                           
                                           -----------------------

                                           -----------------------

                                   Attention:     
                                             ---------------------
                                   Telecopy: 
                                             ---------------------
                                   Telephone:
                                             ---------------------





                                      -4-
<PAGE>   81
                                   Eurodollar Lending Office:



                                   By:
                                      ----------------------------
                                   Name:
                                        --------------------------
                                   Title:
                                         -------------------------

                                   Address:
                                           -----------------------
                                           
                                           -----------------------

                                           -----------------------

                                   Attention:     
                                             ---------------------
                                   Telecopy: 
                                             ---------------------
                                   Telephone:
                                             ---------------------


                                   NATIONSBANK OF TEXAS, N.A.,
                                   as Agent for Itself and the Banks


                                   By:
                                      ----------------------------
                                   Name:
                                        --------------------------
                                   Title:
                                         -------------------------

                                   Address:       901 Main Street
                                                  Dallas, Texas 75202

                                   Attention:  Ms. Denise Ashford Smith
                                   Telecopy:  (214) 508-1285
                                   Telephone: (214) 508-1261





                                      -5-
<PAGE>   82
                                   EXHIBIT D

                    [FORM OF OPINION OF GENERAL COUNSEL FOR
                        THE BORROWER AND THE GUARANTOR]


                               February 27, 1997


To each of the lenders parties to
  the Credit Agreement herein
  described and  to NationsBank
  of Texas, N.A., as Agent

Ladies and Gentlemen:

This opinion is furnished to you pursuant to Section 3.01 of the U.S.
$100,000,000 364-Day Credit Agreement dated as of February 27, 1997 (the
"Credit Agreement"), among Fina Oil and Chemical Company, as borrower (the
"Borrower"), Fina, Inc., as guarantor (the "Guarantor"), the banks parties
thereto (the "Banks"), CIBC Inc. and Texas Commerce Bank National Association,
as Co-Agents, NationsBanc Capital Markets, Inc., as Arranger & Syndication
Agent, and NationsBank of Texas, N.A., as Agent for the Banks.  Terms defined
in the Credit Agreement are used herein as therein defined.

       [Opinion format of rendering counsel to be supplied by such counsel.]

                                   Opinions:

              i.            Each of the Borrower and the Guarantor is a
                     corporation duly organized, validly existing and in good
                     standing under the laws of the State of Delaware.

              ii.           Each of (i) the execution, delivery and performance
                     by each of the Borrower and the Guarantor of the Credit
                     Agreement, (ii) the execution, delivery and performance by
                     the Borrower of the A Notes and the other Notes to be
                     executed by the Borrower, and (iii) the consummation of
                     the transactions contemplated by the Credit Agreement, are
                     within the corporate powers of the Borrower and the
                     Guarantor, respectively, have been duly authorized by all
                     necessary corporate action, do not contravene (x) the
                     Certificate of Incorporation or the By-laws of the
                     Borrower or the Guarantor,





<PAGE>   83
                     respectively, or (y) any law, rule or regulation
                     applicable to the Borrower or the Guarantor (including,
                     without limitation, Regulation X of the Board of Governors
                     of the Federal Reserve System) or (z) any contractual or
                     legal restriction and will not result in or require the
                     creation or imposition of any Lien prohibited by the
                     Credit Agreement.  With respect to the Notes to be
                     executed after the date hereof by the Borrower, this
                     opinion is limited to laws, rules and regulations as in
                     force and applied on the date hereof, the Certificate of
                     Incorporation and the Bylaws of the Borrower, and
                     restrictions in effect on the date hereof.  The Credit
                     Agreement has been duly executed and delivered by the
                     Borrower and the Guarantor, and the A Notes have been duly
                     executed and delivered by the Borrower.

              iii.          No authorization, approval or other action by, and
                     no notice to or filing with, any governmental authority or
                     regulatory body is required for the due execution,
                     delivery and performance by the Borrower or the Guarantor
                     of the Credit Agreement, and (in the case of the Borrower)
                     the respective Notes or the consummation of the
                     transactions contemplated by the Credit Agreement.

              iv.           The A Notes executed by the Borrower constitute,
                     and each Note hereafter executed by the Borrower will
                     constitute, a legal, valid and binding obligation of the
                     Borrower, enforceable against the Borrower in accordance
                     with its terms.  The Credit Agreement executed by the
                     Borrower and the Guarantor constitutes legal, valid and
                     binding obligations of the Borrower and the Guarantor,
                     respectively, enforceable against the Borrower and the
                     Guarantor in accordance with its terms.

              v.            There are no pending or overtly threatened actions
                     or proceedings against the Borrower, the Guarantor or any
                     of their respective Subsidiaries before any court,
                     governmental agency or arbitrator which purport to affect
                     the legality, validity, binding effect or enforceability
                     of the Credit Agreement or any of the Notes or which could
                     reasonably be expected to have a materially adverse effect
                     upon the financial condition or operations of the Borrower
                     and its Subsidiaries taken as a whole, or the Guarantor
                     and its Subsidiaries taken as a whole.

              vi.           Neither the Borrower nor the Guarantor is an
                     "investment company" or a company "controlled" by an
                     "investment company" within the meaning of the Investment
                     Company Act of 1940, as amended.  Neither the Borrower nor
                     the Guarantor is a "holding company", or a "subsidiary
                     company" of a





                                      -2-
<PAGE>   84
                     "holding company", or an "affiliate" of a "holding
                     company" or of a "subsidiary company" of a "holding
                     company", or a "public utility" within the meaning of the
                     Public Utility Holding Company Act of 1935, as amended.



                                        Very truly yours,





                                      -3-
<PAGE>   85
                                   EXHIBIT E

                  FORM OF OPINION OF SPECIAL COUNSEL TO AGENT





                               February 27, 1997


To each of the lenders parties
  to the Credit Agreement
  herein described and to
  NationsBank of Texas, N.A.,
  as Agent

Ladies and Gentlemen:

We have acted as special counsel to NationsBank of Texas, N.A., acting for
itself and as Agent, in connection with the preparation, execution and delivery
of the U.S.$100,000,000 364-Day Credit Agreement dated as of February 27, 1997
(the "Credit Agreement"), among Fina Oil and Chemical Company, as borrower (the
"Borrower"), Fina, Inc., as guarantor (the "Guarantor"), CIBC Inc. and Texas
Commerce Bank National Association, as Co-Agents, NationsBanc Capital Markets,
Inc., as Arranger & Syndication Agent, NationsBank of Texas, N.A., as agent
(the "Agent"), and each of you named as Banks thereunder.  Terms defined in the
Credit Agreement are used herein as therein defined.

In that connection, we have examined the following documents:

              (i)    counterparts of the Credit Agreement, executed by the
       Agent, the Borrower, and the Guarantor, respectively;

              (ii)   the A Notes dated as of February 27, 1997 of the Borrower
       payable to the order of each Bank party to the Credit Agreement as of
       the date hereof (the "A Notes"); and

              (iii)  the opinion dated February 27, 1997 of Cullen M. Godfrey,
       General Counsel for each of the Borrower and the Guarantor ("Opinion").

In our examination of the documents referred to above, we have assumed the
authenticity of all such documents submitted to us as originals, the
genuineness of all signatures and the conformity to the originals of all such
documents submitted to us as copies.  We have also assumed that each of the
Borrower, the Guarantor, the Banks and the Agent has duly executed and
delivered, with all necessary power and authority (corporate and otherwise),
the Credit Agreement, that the Borrower has duly executed and delivered, with
all necessary power and authority (corporate and otherwise),





<PAGE>   86
February 27, 1997
Page 2



the A Notes.  We have also assumed that no Bank has requested that the Opinion
required by Section 3.01(d) of the Credit Agreement contain any other matters
not contained in the form of opinion set forth as Exhibit D to the Credit
Agreement.

Based upon the foregoing examination of documents and assumptions and upon such
other investigation as we have deemed necessary, we are of the opinion that the
A Notes and the Opinion, are substantially responsive to the requirements of
the Credit Agreement.

This opinion is solely for the benefit of the Banks, the Agent, their
respective successors, assigns, participants and other transferees and may be
relied upon only by such Persons.



                                        Very truly yours,



                                        Bracewell & Patterson, L.L.P.





<PAGE>   87
                                   EXHIBIT F


                          FORM OF ACCESSION AGREEMENT


       [NAME OF BANK]             , hereby agrees with Fina Oil and Chemical
Company, as Borrower, Fina, Inc., as Guarantor, and NationsBank of Texas, N.A.,
as Agent under  the U.S.$100,000,000 364-Day Credit Agreement dated as of
February 27, 1997 (as it may be amended from time to time in accordance with
its terms, the "Credit Agreement") among the Borrower, the Guarantor, the Banks
parties thereto, CIBC Inc. and Texas Commerce Bank National Association, as
Co-Agents, NationsBanc Capital Markets, Inc., as Arranger & Syndication Agent,
and NationsBank of Texas, N.A., as Agent for the Banks (as such agreement is
amended from time to time in accordance with its terms, the "Credit Agreement";
capitalized terms used herein and not otherwise defined having the meanings set
forth therein), as follows:

       The undersigned hereby agrees and confirms that, as of the date hereof,
it (a) intends to be a Bank party to the Credit Agreement with a Commitment of
$____________ in connection with the proposed increase of the aggregate
Commitments pursunt to Section 2.15 of the Credit Agreement to $__________, and
undertakes to perform all the obligations expressed therein as a Bank; (b) has
received a copy of the Credit Agreement, together with copies of the financial
statements referred to in Section 5.05 thereof and such other documents and
information as it has deemed appropriate to make its own credit analysis and
decision to enter into this Accession Agreement and become a Bank under the
Credit Agreement; (c) will, independently and without reliance upon the Agent
or any Bank, and based on such documents and information as it shall deem
appropriate at the time, continue to make its own credit decisions in taking or
not taking action under the Credit Agreement; (d) appoints and authorizes the
Agent to take such action as agent on its behalf and to exercise such powers
under the Credit Agreement as are delegated to the Agent by the terms thereof,
together with such powers as are reasonably incidental thereto; (e) agrees that
it will perform in accordance with their terms all of the obligations which by
the terms of the Credit Agreement are required to be performed by it as a Bank;
(f) specifies as its Domestic Lending Office (and address for notices) and
Eurodollar Lending Office the offices set forth beneath its name on the
signature pages hereof; (g) attaches the forms prescribed by the Internal
Revenue Service of the United States certifying as to its status for purposes
of determining exemption from United States withholding taxes with respect to
all payments to be made to it under the Credit Agreement and its Note(s) or
such other documents as are necessary to indicate that all such payments are
subject to





<PAGE>   88



such rates at a rate reduced by an applicable tax treaty*****, and
(h) represents that it is an Eligible Assignee.

       The effective date for this Accession Agreement shall be the date the
related increase in the aggregate Commitments becomes effective in accordance
with the terms of Section 2.15 of the Credit Agreement (the "Effective Date")
and following the execution of this Accession Agreement, the Agent will record
it.  Upon such recording, and as of the Effective Date, (i) the undersigned
shall be a Bank party to the Credit Agreement for all purposes, and, to the
extent of its Commitment, shall have the rights and obligations of a Bank
thereunder.

       This Accession Agreement shall be construed as a contract governed in
accordance with the laws of the State of Texas.

       IN WITNESS WHEREOF this Accession Agreement was executed and delivered
as of the ___ day of _________, ____.



                                           [NAME OF NEW BANK]



                                           
                                           ---------------------------
                                           By:
                                              ------------------------
                                           Title:
                                                 ---------------------

                                           Domestic Lending Office:
                                           ----------------------- 

                                           Address:
                                                   -------------------------

                                           Attention:  
                                                     -----------------------
                                           Telecopy:   
                                                    ------------------------
                                           Telephone:  
                                                     -----------------------





--------------------

  (1) If the New Bank is organized under the laws of a jurisdiction outside the
      United States.





                                     -2-
<PAGE>   89



                                           Eurodollar Lending Office:
                                           ------------------------- 

                                           Address:    
                                                     -----------------------
                                           Attention:  
                                                     -----------------------
                                           Telecopy:   
                                                    ------------------------
                                           Telephone:  
                                                     -----------------------


Acknowledged and Agreed By:

FINA OIL AND CHEMICAL COMPANY



-------------------------------
By:
   ----------------------------
Title:
      -------------------------

FINA, INC.


-------------------------------
By:
   ----------------------------
Title:
      -------------------------


NATIONSBANK OF TEXAS, N.A.



-------------------------------
By:
   ----------------------------
Title:
      -------------------------





<PAGE>   90


                                   EXHIBIT G


                   FORM OF CONSENT TO INCREASE OF COMMITMENT


       [NAME OF BANK]             , hereby agrees with Fina Oil and Chemical
Company, as Borrower, Fina, Inc., as Guarantor, and NationsBank of Texas, N.A.,
as Agent under  the U.S.$100,000,000 364-Day Credit Agreement dated as of
February 27, 1997 (as it may be amended from time to time in accordance with
its terms, the "Credit Agreement") among the Borrower, the Guarantor, the
undersigned and the other Banks parties thereto, CIBC Inc. and Texas Commerce
Bank National Association, as Co-Agents, NationsBanc Capital Markets, Inc., as
Arranger & Syndication Agent, and NationsBank of Texas, N.A., as Agent for the
Banks (as such agreement is amended from time to time in accordance with its
terms, the "Credit Agreement"; capitalized terms used herein and not otherwise
defined having the meanings set forth therein), as follows:

       The undersigned hereby agrees and confirms that, as of the date hereof,
it  intends to increase its Commitment under the Credit Agreement to
$____________ in connection with the proposed increase of the aggregate
Commitments pursunt to Section 2.15 of the Credit Agreement to $__________.

       The effective date for this Consent and for the increase of the
undersigned's Commitment as set forth in the preceding paragraph shall be the
date the related increase in the aggregate Commitments becomes effective in
accordance with the terms of Section 2.15 of the Credit Agreement (the
"Effective Date").

       This Consent shall be construed as a contract governed in accordance
with the laws of the State of Texas.

       IN WITNESS WHEREOF this Consent was executed and delivered as of the ___
day of _________, ____.



                                           [NAME OF BANK]


                                           -------------------------------
                                           By:                            
                                              ----------------------------
                                           Title:                         
                                                 -------------------------





<PAGE>   91
Acknowledged and Agreed By:

FINA OIL AND CHEMICAL COMPANY



-------------------------------
By:                            
   ----------------------------
Title:                         
      -------------------------

FINA, INC.


-------------------------------
By:                            
   ----------------------------
Title:                         
      -------------------------

NATIONSBANK OF TEXAS, N.A.



-------------------------------
By:                            
   ----------------------------
Title:                         
      -------------------------




<PAGE>   92

                                                                  EXECUTION COPY



                               U.S. $325,000,000

                            5-YEAR CREDIT AGREEMENT

                         Dated as of February 27, 1997

                                     Among

                         FINA OIL AND CHEMICAL COMPANY

                                  as Borrower

                                   FINA, INC.

                                  as Guarantor

                             THE BANKS NAMED HEREIN

                                    as Banks

                                   CIBC INC.
                    TEXAS COMMERCE BANK NATIONAL ASSOCIATION

                                  as Co-Agents

                       NATIONSBANC CAPITAL MARKETS, INC.

                        as Arranger & Syndication Agent

                                      and

                           NATIONSBANK OF TEXAS, N.A.

                                    as Agent
<PAGE>   93
                               TABLE OF CONTENTS
                               -----------------
<TABLE>
<CAPTION>
       Section                                                               Page
       -------                                                               ----
                            ARTICLE I
                        DEFINITIONS AND ACCOUNTING TERMS
       <S>           <C>                                                      <C>
       Section 1.01.  Certain Defined Terms   . . . . . . . . . . . . . . .    1
       Section 1.02.  Computation of Time Periods   . . . . . . . . . . . .   12
       Section 1.03.  Accounting Terms  . . . . . . . . . . . . . . . . . .   12
       Section 1.04.  Miscellaneous   . . . . . . . . . . . . . . . . . . .   12


                                   ARTICLE II

                        AMOUNTS AND TERMS OF THE ADVANCES

       Section 2.01.  The A Advances  . . . . . . . . . . . . . . . . . . .   13
       Section 2.02.  Making the A Advances   . . . . . . . . . . . . . . .   13
       Section 2.03.  Fees  . . . . . . . . . . . . . . . . . . . . . . . .   16
       Section 2.04.  Optional Reduction of the Commitments   . . . . . . .   16
       Section 2.05.  Repayment and Prepayment of A Advances  . . . . . . .   17
       Section 2.06.  Interest on A Advances  . . . . . . . . . . . . . . .   17
       Section 2.07.  Interest Rate Determination   . . . . . . . . . . . .   18
       Section 2.08.  The B Advances  . . . . . . . . . . . . . . . . . . .   18
       Section 2.09.  Payments, Computations; Interest on Overdue
                        Amounts . . . . . . . . . . . . . . . . . . . . . .   21
       Section 2.10.  Consequential Losses  . . . . . . . . . . . . . . . .   22
       Section 2.11.  Increased Costs   . . . . . . . . . . . . . . . . . .   22
       Section 2.12.  Illegality  . . . . . . . . . . . . . . . . . . . . .   24
       Section 2.13.  Taxes   . . . . . . . . . . . . . . . . . . . . . . .   24
       Section 2.14.  Payments Pro Rata   . . . . . . . . . . . . . . . . .   26
       Section 2.15.  Increase of Aggregate Commitments   . . . . . . . . .   26


                                   ARTICLE III

                                   CONDITIONS

       Section 3.01.  Conditions Precedent to Effectiveness   . . . . . . .   28
       Section 3.02.  Conditions Precedent to Each A Borrowing  . . . . . .   29

</TABLE>




                                      -i-
<PAGE>   94
<TABLE>
       <S>            <C>                                                     <C>
       Section 3.03.  Conditions Precedent to Certain Borrowings  . . . . .   30
       Section 3.04.  Conditions Precedent to Each B Borrowing  . . . . . .   30


                                   ARTICLE IV

                                    GUARANTY

       Section 4.01.  Guaranty  . . . . . . . . . . . . . . . . . . . . . .   31
       Section 4.02.  Guaranty Absolute   . . . . . . . . . . . . . . . . .   31
       Section 4.03.  Waiver.   . . . . . . . . . . . . . . . . . . . . . .   32
       Section 4.04.  Subrogation   . . . . . . . . . . . . . . . . . . . .   32
       Section 4.05.  No Waiver; Remedies   . . . . . . . . . . . . . . . .   32
       Section 4.06.  Continuing Guaranty   . . . . . . . . . . . . . . . .   32


                                    ARTICLE V

                         REPRESENTATIONS AND WARRANTIES

       Section 5.01.  Corporate Existence   . . . . . . . . . . . . . . . .   33
       Section 5.02.  Corporate Power   . . . . . . . . . . . . . . . . . .   33
       Section 5.03.  Authorization and Approvals   . . . . . . . . . . . .   33
       Section 5.04.  Enforceable Obligations   . . . . . . . . . . . . . .   34
       Section 5.05.  Financial Statements  . . . . . . . . . . . . . . . .   34
       Section 5.06.  Litigation  . . . . . . . . . . . . . . . . . . . . .   35
       Section 5.07.  Regulation U; Use of Proceeds   . . . . . . . . . . .   35
       Section 5.08.  Investment Company Act  . . . . . . . . . . . . . . .   35
       Section 5.09.  ERISA   . . . . . . . . . . . . . . . . . . . . . . .   35
       Section 5.10.  Taxes   . . . . . . . . . . . . . . . . . . . . . . .   35
       Section 5.11.  Holding Company   . . . . . . . . . . . . . . . . . .   36
       Section 5.12.  Environmental Condition   . . . . . . . . . . . . . .   36
       Section 5.13.  Ownership of Borrower   . . . . . . . . . . . . . . .   36
       Section 5.14.  Guarantor's Independent Decision  . . . . . . . . . .   36


                                   ARTICLE VI

                              AFFIRMATIVE COVENANTS

       Section 6.01.  Compliance with Laws, Etc.  . . . . . . . . . . . . .   36
       Section 6.02.  Reporting Requirements  . . . . . . . . . . . . . . .   37
</TABLE>





                                      -ii-
<PAGE>   95
<TABLE>
       <S>                                                                    <C>
       Section 6.03.  Use of Proceeds   . . . . . . . . . . . . . . . . . .   39
       Section 6.04.  Maintenance of Insurance  . . . . . . . . . . . . . .   39
       Section 6.05.  Preservation of Corporate Existence, Etc.   . . . . .   39
       Section 6.06.  Payment of Taxes, Etc.  . . . . . . . . . . . . . . .   39
       Section 6.07.  Visitation Rights   . . . . . . . . . . . . . . . . .   39


                                   ARTICLE VII

                               NEGATIVE COVENANTS

       Section 7.01.  Financial Covenants   . . . . . . . . . . . . . . . .   40
       Section 7.02.  Liens, Etc.   . . . . . . . . . . . . . . . . . . . .   40
       Section 7.03.  Merger and Sale of Assets   . . . . . . . . . . . . .   40
       Section 7.04.  Agreements to Restrict Dividends and Certain
                        Transfers . . . . . . . . . . . . . . . . . . . . .   41
       Section 7.05.  Compliance with ERISA   . . . . . . . . . . . . . . .   41
       Section 7.06.  Transactions with Affiliates  . . . . . . . . . . . .   41
       Section 7.07.  Change of Business  . . . . . . . . . . . . . . . . .   42
       Section 7.08.  Limitation on Loans, Advances and Investments   . . .   42
       Section 7.09.  Fiscal Year; Accounting Practices   . . . . . . . . .   42


                                  ARTICLE VIII

                                EVENTS OF DEFAULT

       Section 8.01.  Events of Default   . . . . . . . . . . . . . . . . .   43


                                   ARTICLE IX

         THE AGENT, THE CO-AGENTS, AND THE ARRANGER & SYNDICATION AGENT

       Section 9.01.  Authorization and Action  . . . . . . . . . . . . . .   46
       Section 9.02.  Agent's Reliance, Etc.  . . . . . . . . . . . . . . .   46
       Section 9.03.  NationsBank and Affiliates  . . . . . . . . . . . . .   46
       Section 9.04.  Bank Credit Decision  . . . . . . . . . . . . . . . .   47
       Section 9.05.  Indemnification   . . . . . . . . . . . . . . . . . .   47
       Section 9.06.  Successor Agent   . . . . . . . . . . . . . . . . . .   48
       Section 9.07.  Co-Agents; Arranger & Syndication Agent   . . . . . .   48
</TABLE>





                                     -iii-
<PAGE>   96
                                   ARTICLE X

                                 MISCELLANEOUS

<TABLE>
       <S>             <C>                                                    <C>
       Section 10.01.  Amendments, Etc.   . . . . . . . . . . . . . . . . .   48
       Section 10.02.  Notices, Etc.  . . . . . . . . . . . . . . . . . . .   49
       Section 10.03.  No Waiver; Remedies  . . . . . . . . . . . . . . . .   49
       Section 10.04.  Costs, Expenses and Taxes  . . . . . . . . . . . . .   50
       Section 10.05.  Right of Set-off   . . . . . . . . . . . . . . . . .   50
       Section 10.06.  Bank Assignments and Participations  . . . . . . . .   51
       Section 10.07.  Governing Law  . . . . . . . . . . . . . . . . . . .   53
       Section 10.08.  Interest   . . . . . . . . . . . . . . . . . . . . .   53
       Section 10.09.  Execution in Counterparts  . . . . . . . . . . . . .   54
       Section 10.10.  Survival of Agreements, Representations and
                         Warranties, Etc.   . . . . . . . . . . . . . . . .   54
       Section 10.11.  Borrower's Right to Apply Deposits   . . . . . . . .   54
       Section 10.12.  Confidentiality  . . . . . . . . . . . . . . . . . .   55
       Section 10.13.  Binding Effect   . . . . . . . . . . . . . . . . . .   55
       Section 10.14.  Entire Agreement   . . . . . . . . . . . . . . . . .   55
       Section 10.15.  Severability   . . . . . . . . . . . . . . . . . . .   56
</TABLE>





                                      -iv-
<PAGE>   97
Schedule I    -      Agent and Bank Information

Schedule II   -      Borrower and Guarantor Information

Schedule III  -      Existing Permitted Liens  (7.02)

Schedule IV   -      Certain Existing Transfer Restrictions (7.04)

Schedule V    -      Certain Loans and Investments (7.08)

Exhibit A-1   -      Form of A Note

Exhibit A-2   -      Form of B Note

Exhibit B-1   -      Notice of A Borrowing

Exhibit B-2   -      Notice of B Borrowing

Exhibit C     -      Form of Assignment and Acceptance

Exhibit D     -      Opinion of Counsel for the Borrower and the Guarantor

Exhibit E     -      Opinion of Special Counsel to Agent

Exhibit F     -      Form of Accession Agreement

Exhibit G     -      Form of Consent to Increase in Commitment





                                      -v-
<PAGE>   98
                                CREDIT AGREEMENT

                         Dated as of February 27, 1997


       This Credit Agreement dated as of February 27, 1997, is by and among the
Borrower, the Guarantor, the Agent, the Co-Agents, the Arranger & Syndication
Agent and the Banks.  In consideration of the mutual covenants and agreements
contained herein, the Borrower, the Guarantor, the Agent, the Co-Agents, the
Arranger & Syndication Agent and the Banks hereby agree as follows:


                                   ARTICLE I

                        DEFINITIONS AND ACCOUNTING TERMS

       Section 1.01.  Certain Defined Terms.  As used in this Agreement, the
following terms shall have the following meanings (such meanings to be equally
applicable to both the singular and plural forms of the terms defined):

       "A Advance" means an advance by a Bank to the Borrower as part of an A
Borrowing and refers to a Base Rate Advance or a Eurodollar Rate Advance, each
of which shall be a "Type" of A Advance.

       "A Borrowing" means a borrowing consisting of simultaneous A Advances of
the same Type to the Borrower made by each of the Banks pursuant to Section
2.01.

       "A Note" means a promissory note of the Borrower payable to the order of
any Bank, in substantially the form of Exhibit A-1 hereto, evidencing the
aggregate indebtedness of the Borrower to such Bank resulting from A Advances.

       "Accession Agreement" means an Accession Agreement in the form of
Exhibit F duly executed by the Borrower, the Guarantor, the Agent, and a New
Bank in connection with an increase in the aggregate Commitments permitted
pursuant to Section 2.15.

       "Advance" means an A Advance or a B Advance.

       "Affiliate" of any Person means any corporation, partnership, limited
liability company, limited liability partnership, joint venture or other entity
of which more than 10% of the outstanding capital stock or other equity
interests having ordinary voting power to elect a majority of the board of
directors of such corporation, partnership, limited liability company, limited
liability partnership, joint venture or other entity or others performing
similar functions (irrespective of whether or not at the time capital stock or
other equity interests of any other class or classes of such corporation,





<PAGE>   99
partnership, limited liability company, limited liability partnership, joint
venture or other entity shall or might have voting power upon the occurrence of
any contingency) is at the time directly or indirectly owned by such Person or
which owns at the time directly or indirectly more than 10% of the outstanding
capital stock or other equity interests having ordinary voting power to elect a
majority of the board of directors of such Person or others performing similar
functions (irrespective of whether or not at the time capital stock or other
equity interests of any other class or classes of such corporation,
partnership, limited liability company, limited liability partnership, joint
venture or other entity shall or might have voting power upon the occurrence of
any contingency).

       "Agent" means NationsBank of Texas, N.A. in its capacity as agent
pursuant to Article IX hereof and any successor Agent pursuant to Section 9.06.

       "Agent's Fee Letter" means the letter agreement dated as of January 24,
1997 among the Agent, the Borrower and the Guarantor.

       "Aggregate Commitment Limit" means $550,000,000.

       "Agreement" means this Credit Agreement dated as of February 27, 1997
among the Borrower, the Guarantor, the Agent, the Co-Agents, the Arranger &
Syndication Agent and the Banks, as amended or modified from time to time.

       "Applicable Lending Office" means, with respect to each Bank, such
Bank's Domestic Lending Office in the case of a Base Rate Advance and such
Bank's Eurodollar Lending Office in the case of a Eurodollar Rate Advance and,
in the case of a B Advance, the office of such Bank notified by such Bank to
the Agent as its Applicable Lending Office with respect to such B Advance.

       "Applicable Facility Fee" means, at any time the facility fee described
in Section 2.03 is to be paid, the following percentages per annum determined
as a function of the Guarantor's senior unsecured debt rating according to S&P
or Moody's, whichever is higher, on the last day of the immediately preceding
calendar quarter:

              Rating A+/A1           .06%

              Rating A/A2            .07%

              Rating A-/A3           .08%

              Rating BBB+/Baa1
              or BBB/Baa2            .10%

              Rating BBB-/Baa3       .15%

              Rating BB+/Ba1

              or below               .20%





                                      -2-
<PAGE>   100
       "Applicable Margin" means, at any time with respect to any A Advance
which is a Eurodollar Rate Advance, the following percentages determined as a
function of the Guarantor's senior unsecured debt rating according to S&P or
Moody's, whichever is higher, on the last day of the immediately preceding
calendar quarter:

              Rating A+/A1                 0.14%

              Rating A/A2                  0.15%

              Rating A-/A3                 0.165%

              Rating BBB+/Baa1
              or BBB/Baa2                  0.20%

              Rating BBB-/Baa3             0.275%

              Rating BB+/Ba1
              or below                     0.425%

       "Assignment" means an assignment and acceptance entered into by a Bank
and an Eligible Assignee, and accepted by the Agent, in substantially the form
of the attached Exhibit C.

       "B Advance" means an advance by a Bank to the Borrower as part of a B
Borrowing resulting from the auction bidding procedure described in Section
2.08.

       "B Borrowing" means a borrowing consisting of simultaneous B Advances to
the Borrower from each of the Banks whose offer to make one or more B Advances
as part of such borrowing has been accepted by the Borrower under the auction
bidding procedure described in Section 2.08.

       "B Note" means a promissory note of the Borrower payable to the order of
any Bank, in substantially the form of Exhibit A-2 hereto, evidencing the
indebtedness of the Borrower to such Bank resulting from a B Advance made to
the Borrower by such Bank.

       "B Reduction" has the meaning specified in Section 2.01.

       "Banks" means the banks listed on the signature pages hereof and each
other Person that becomes a Bank pursuant to an Assignment or an Accession
Agreement.

       "Base Rate" means a fluctuating interest rate per annum as shall be in
effect from time to time which rate per annum shall at all times be equal to
the highest of:





                                      -3-
<PAGE>   101
       (a)    the rate of interest announced publicly by NationsBank,
from time to time, as NationsBank's prime rate; or

       (b)     1/2 of one percent per annum above the Federal Funds Rate in
effect from time to time.

       "Base Rate Advance" means an A Advance which bears interest as provided
in Section 2.06(a).

       "Borrower" means Fina Oil and Chemical Company, a Delaware corporation.

       "Borrowing" means an A Borrowing or a B Borrowing.

       "Business Day" means a day of the year on which banks are not required
or authorized to close in Dallas, Texas or New York City and, if the applicable
Business Day relates to any Eurodollar Rate Advances, on which dealings are
carried on in the London interbank market.

       "Capitalization" means for any Person the sum of Consolidated Debt of
such Person plus the Consolidated Tangible Net Worth of such Person.

       "Co-Agent" means either CIBC Inc. or Texas Commerce Bank National
Association in its capacity as co-agent pursuant to Article IX hereof, and "Co-
Agents" means such banks collectively.

       "Code" means, as appropriate, the Internal Revenue Code of 1986, as
amended, or any successor Federal tax code, and any reference to any statutory
provision shall be deemed to be a reference to any successor provision or
provisions.

       "Commitment" of any Bank means at any time the amount set forth as the
"Commitment" of such Bank on the signature pages of this Agreement, or if such
Bank has executed an Assignment or a Consent to Increase of Commitment, then
the amount set forth as the "Commitment" of such Bank therein, or if such Bank
is a New Bank, then the amount set forth as the "Commitment" of such Bank in
the Accession Agreement executed by such Bank, in each case as such amount may
be terminated or reduced pursuant to Section 2.04 or Section 8.01.

       "Consolidated" refers to the consolidation of the accounts of any Person
and its subsidiaries in accordance with generally accepted accounting
principles.

       "Credit Documents" means this Agreement, the Notes, and each other
agreement, instrument or document executed by the Borrower or the Guarantor at
any time in connection with this Agreement.

       "Debt" means, in the case of any Person,  (i) indebtedness of such
Person for borrowed money, (ii) obligations of such Person evidenced by bonds,
debentures, notes or other similar instruments, (iii) obligations of such
Person to pay the deferred purchase price of property or





                                      -4-
<PAGE>   102
services, (iv) obligations of such Person as lessee under leases which are, in
accordance with generally accepted accounting principles, recorded as capital
leases, (v) obligations of such Person in connection with production payments
(except for obligations incurred in connection with Volumetric Production
Payments, stated as either deferred credits or deferred revenues in amounts
outstanding at any time that do not exceed, in the aggregate, 10 percent of
Borrower's Tangible Net Worth), (vi) all liabilities of such Person in respect
of unfunded vested benefits under any Plan, (vii) obligations of such Person
under or relating to letters of credit or guaranties in respect of, and
obligations (contingent or otherwise) to purchase or otherwise acquire, or
otherwise to assure a creditor against loss in respect of, indebtedness or
obligations of others of the kinds referred to in clauses (i) through (vi) of
this definition, and (viii) indebtedness or obligations of others of the kinds
referred to in clauses (i) through (vii) of this definition secured by any Lien
on or in respect of any property of such Person (limited, however, to the
lesser of the amount of its liability or the value of such property).

       "Default" means an Event of Default or an event which, with the giving
of notice or lapse of time or both, would constitute an Event of Default.

       "Domestic Lending Office" means, with respect to any Bank, the office of
such Bank specified as its "Domestic Lending Office" opposite its name on
Schedule I hereto or in an Assignment or such other office of such Bank as such
Bank may from time to time specify to the Borrower and the Agent.

       "Effective Date" means the date that all of the conditions in Section
3.01 shall have been satisfied or waived.

       "Eligible Assignee" means (i) a Bank or (ii) a commercial bank or
financial institution or other Person acceptable to the Agent and the Borrower,
such acceptance not to be unreasonably withheld.

       "Environment" or "Environmental" shall have the meanings set forth in 42
U.S.C. Section 9601(8) (1982).

       "Environmental Protection Statute" shall mean any United States local,
state or federal, or any foreign, law, statute, regulation, order, consent
decree or other agreement or Governmental Requirement arising from or in
connection with or relating to the protection or regulation of the Environment,
including, without limitation, those laws, statutes, regulations, orders,
decrees, agreements and other Governmental Requirements relating to the
disposal, cleanup, production, storing, refining, handling, transferring,
processing or transporting of Hazardous Waste, Hazardous Substances or any
pollutant or contaminant, wherever located.

       "ERISA" means the Employee Retirement Income Security Act of 1974, as
amended from time to time, and the regulations promulgated and rulings issued
thereunder from time to time.





                                      -5-
<PAGE>   103
       "ERISA Affiliate" of the Guarantor means any trade or business (whether
or not incorporated) which is a member of a group of which the Guarantor is a
member and which is under common control within the meaning of the regulations
under Section 414 of the Code.

       "Eurocurrency Liabilities" has the meaning assigned to that term in
Regulation D of the Board of Governors of the Federal Reserve System, as in
effect from time to time.

       "Eurodollar Lending Office" means, with respect to any Bank, the office
of such Bank specified as its "Eurodollar Lending Office" opposite its name on
Schedule I hereto or in an Assignment (or, if no such office is specified, its
Domestic Lending Office) or such other office of such Bank as such Bank may
from time to time specify to the Borrower and the Agent.

       "Eurodollar Rate" means, for the Interest Period for each Eurodollar
Rate Advance comprising part of the same A Borrowing, an interest rate per
annum equal to the rate per annum at which deposits in U.S. dollars are offered
by the principal office of each of the Reference Banks in London, England to
prime banks in the London interbank market at 11:00 A.M. (London time) two
Business Days before the first day of such Interest Period in an amount
substantially equal to the amount of the Eurodollar Rate Advance of such
Reference Bank comprising part of such A Borrowing to be outstanding during
such Interest Period and for a period equal to such Interest Period.  The
Eurodollar Rate for the Interest Period for each Eurodollar Rate Advance
comprising part of the same A Borrowing shall be determined by the Agent on the
basis of applicable rates furnished to and received by the Agent from the
Reference Banks two Business Days before the first day of such Interest Period.

       "Eurodollar Rate Advance" means an A Advance which bears interest as
provided in Section 2.06(b).

       "Eurodollar Rate Reserve Percentage" of any Bank for the Interest Period
for any Eurodollar Rate Advance means the reserve percentage applicable during
such Interest Period (or if more than one such percentage shall be so
applicable, the daily average of such percentages for those days in such
Interest Period during which any such percentage shall be so applicable) under
regulations issued from time to time by the Board of Governors of the Federal
Reserve System (or any successor) for determining the maximum reserve
requirement (including, without limitation, any emergency, supplemental or
other marginal reserve requirement) for such Bank with respect to liabilities
or assets consisting of or including Eurocurrency Liabilities having a term
equal to such Interest Period.

       "Events of Default" has the meaning specified in Section 8.01.

       "Federal Funds Rate" means, for any period, a fluctuating interest rate
per annum equal for each day during such period to the weighted average of the
rates on overnight Federal funds transactions with members of the Federal
Reserve System arranged by Federal funds brokers, as published for such day
(or, if such day is not a Business Day, for the next preceding Business Day)





                                      -6-
<PAGE>   104
by the Federal Reserve Bank of New York, or, if such rate is not so published
for any day which is a Business Day, the average of the quotations for such day
on such transactions received by the Agent from three Federal funds brokers of
recognized standing selected by it.

       "Fixed Rate Advance" means (i) any A Advance which is a Eurodollar Rate
Advance and (ii) any B Advance.

       "Governmental Requirements" means all judgments, orders, writs,
injunctions, decrees, awards, laws, ordinances, statutes, regulations, rules,
franchises, permits, certificates, licenses, authorizations and the like and
any other requirements of any government or any commission, board, court,
agency, instrumentality or political subdivision thereof.

       "Guaranteed Obligations" means all obligations of the Borrower to the
Banks hereunder and under the Notes or any other Credit Document to which the
Borrower is a party, whether for principal, interest, fees, expenses,
indemnities or otherwise, and whether now or hereafter existing.

       "Guarantor" means Fina, Inc., a Delaware corporation.

       "Hazardous Substance" shall have the meaning set forth in 42 U.S.C.
Section 9601(14) and shall also include each other substance considered to be a
hazardous substance under any Environmental Protection Statute.

       "Hazardous Waste" shall have the meaning set forth in 42 U.S.C. Section
6903(5) and shall also include each other substance considered to be a
hazardous waste under any Environmental Protection Statute (including, without
limitation 40 C.F.R. Section 261.3).

       "Insufficiency" means, with respect to any Plan, the amount, if any, by
which the present value of the vested benefits under such Plan exceeds the fair
market value of the assets of such Plan allocable to such benefits.

       "Interest Period" means, for each A Advance comprising part of the same
A Borrowing, the period commencing on the date of such A Advance and ending on
the last day of the period selected by the Borrower pursuant to the provisions
below and Section 2.02.  The duration of each such Interest Period shall be (a)
in the case of a Base Rate Advance, the period commencing on the date of such
Advance and ending on the last day of the then current calendar quarter and (b)
in the case of a Eurodollar Rate Advance, one, two, three, or six months, in
each case as the Borrower may select in the applicable Notice of A Borrowing;
provided, however, that:
       
       (i)    Interest Periods commencing on the same date for A
Advances comprising part of the same A Borrowing shall be of the same duration;

       (ii)   whenever the last day of any Interest Period would otherwise
occur on a day other than a Business Day, the last day of such Interest Period
shall be extended to occur on the next





                                      -7-
<PAGE>   105
succeeding Business Day, provided, in the case of any Interest Period for a
Eurodollar Rate Advance, that if such extension would cause the last day of
such Interest Period to occur in the next following calendar month, the last
day of such Interest Period shall occur on the next preceding Business Day;

       (iii)  any Interest Period which begins on the last Business Day of the
calendar month (or on a day for which there is no numerically corresponding day
in the calendar month at the end of such Interest Period) shall end on the last
Business Day of the calendar month in which it would have ended if there were a
numerically corresponding day in such calendar month; and

       (iv)   the Borrower may not select an Interest Period for any A Advance
made prior to the Termination Date if the last day of such Interest Period
would be later than the Termination Date.

       "Lien" means any mortgage, lien, pledge, charge, deed of trust, security
interest, encumbrance or other type of preferential arrangement to secure or
provide for the payment of any obligation of any Person, whether arising by
contract, operation of law or otherwise (including, without limitation, the
interest of a vendor or lessor under any conditional sale agreement, capital
lease or other title retention agreement).

       "Liquid Investments" means:

       (a)    direct obligations of, or obligations the principal of and
interest on which are unconditionally guaranteed by, the United States;

       (b)    (i) negotiable or nonnegotiable certificates of deposit, time
deposits, or other similar banking arrangements maturing within 180 days from
the date of acquisition thereof ("bank debt securities"), issued by (A) any
Bank or (B) any other bank or trust company which has a combined capital
surplus and undivided profit of not less than $250,000,000 or the dollar
equivalent thereof, if at the time of deposit or purchase, such bank debt
securities are rated not less than "A" (or the then equivalent) by the rating
service of S&P or of Moody's, and (ii) commercial paper issued by (A) any Bank
or (B) any other Person if at the time of purchase such commercial paper is
rated not less than "A-2" (or the then equivalent) by the rating service of S&P
or not less than "P-2" (or the then equivalent) by the rating service of
Moody's, or upon the discontinuance of both of such services, such other
nationally recognized rating service or services, as the case may be, as shall
be selected by the Borrower or the Guarantor with the consent of the Majority
Banks;

       (c)    repurchase agreements relating to investments described in
clauses (a) and (b) above with a market value at least equal to the
consideration paid in connection therewith, with any Person who regularly
engages in the business of entering into repurchase agreements and has a
combined capital surplus and undivided profit of not less than $250,000,000 or
the dollar equivalent thereof, if at the time of entering into such agreement
the debt securities of such Person are rated not less than "A" (or the then
equivalent) by the rating service of S&P or of Moody's;





                                      -8-
<PAGE>   106
       (d)    shares of any mutual fund registered under the Investment Company
Act of 1940, as amended, which invests solely in underlying securities of the
types described in clauses (a), (b) and (c) above and which do not constitute
"margin stock" within the meaning of Regulation U of the Federal Reserve Board;
and

       (e)    such other instruments (within the meaning of Article 9 of the
Texas Business and Commerce Code) as the Borrower or the Guarantor may request
and the Majority Banks may approve in writing, which approval will not be
unreasonably withheld.

       "Majority Banks" means at any time Banks holding at least 51% of the
then aggregate unpaid principal amount of the A Notes held by the Banks, or, if
no such principal amount is then outstanding, Banks having at least 51% of the
Commitments or, if no such principal amount is then outstanding and all
Commitments have terminated, Banks holding at least 51% of the then aggregate
unpaid principal amount of the B Notes held by the Banks.

       "Moody's" means Moody's Investors Service, or any successor thereto.

       "Multiemployer Plan" means a "multiemployer plan" as defined in Section
4001(a)(3) of ERISA to which the Guarantor or any ERISA Affiliate of the
Guarantor is making or accruing an obligation to make contributions, or has
within any of the preceding five plan years made or accrued an obligation to
make contributions.

       "Multiple Employer Plan" means an employee benefit plan, other than a
Multiemployer Plan, subject to Title IV of ERISA to which the Guarantor or any
ERISA Affiliate of the Guarantor, and one or more employers other than the
Guarantor or an ERISA Affiliate of the Guarantor, is making or accruing an
obligation to make contributions or, in the event that any such plan has been
terminated, to which the Guarantor or any ERISA Affiliate of the Guarantor made
or accrued an obligation to make contributions during any of the five plan
years preceding the date of termination of such plan.

       "NationsBank" means NationsBank of Texas, N.A.

       "New Bank" means any lender which becomes a "Bank" hereunder by
executing an Accession Agreement pursuant to an increase in the aggregate
Commitments permitted by Section 2.15.

       "Note" means an A Note or a B Note.

       "Notice of A Borrowing" has the meaning specified in Section 2.02(a).

       "Notice of B Borrowing" has the meaning specified in Section 2.08(a).





                                      -9-
<PAGE>   107
       "Parallel Agreement" means the U.S. $100,000,000 364-Day Credit
Agreement dated as of February 27, 1997 among the Borrower, the Guarantor, the
Agent, the Arranger & Syndication Agent and the Banks, as amended or modified
from time to time.

       "Parallel Agreement Commitments" means, as of any date of determination,
the "Commitments" as defined in the Parallel Agreement.

       "PBGC" means the Pension Benefit Guaranty Corporation.

       "Permitted Liens" means, with respect to any Person, Liens:

       (a)    for taxes, assessments or governmental charges or levies on
property of such Person incurred in the ordinary course of business to the
extent not required to be paid pursuant to Sections 6.01 and 6.06;

       (b)    imposed by law, such as landlords', carriers', warehousemen's and
mechanics' liens and other similar Liens arising in the ordinary course of
business securing obligations which are not overdue for a period of more than
15 days or which are being contested in good faith and by appropriate
proceedings if adequate reserves with respect thereto are maintained on the
books of such Person in accordance with generally accepted accounting
principles;

       (c)    arising in the ordinary course of business out of pledges or
deposits under workers' compensation laws, unemployment insurance, old age
pensions or other social security or retirement benefits, or similar
legislation or to secure public or statutory obligations of such Person;

       (d)    securing Debt existing on the date of this Agreement and listed
on the attached Schedule III; provided that the Debt secured by such Liens
shall not be renewed, refinanced or extended if the amount of such Debt so
renewed is greater than the outstanding amount of such Debt on the date of this
Agreement;

       (e)    constituting easements, rights-of-way, restrictions and other
similar encumbrances incurred in the ordinary course of business and
encumbrances consisting of zoning restrictions, easements, licenses,
restrictions on the use of property or minor imperfections in title thereto
which, in the aggregate, are not material in amount, and which do not in any
case materially detract from the value of the property subject thereto or
materially interfere with the ordinary conduct of the business of such Person;

       (f)    securing judgments against such Person which are being appealed
and do not constitute an Event of Default under Section 8.01(f); or

       (g)    on real property acquired by such Person after the date of this
Agreement and securing only Debt of such Person incurred to finance the
purchase price of such property; provided that any such Lien is created within
180 days of the acquisition of such property and provided further





                                      -10-
<PAGE>   108
that the Debt secured by all such Liens does not exceed 35% of Consolidated
Tangible Net Worth of the Guarantor and the Restricted Subsidiaries.

       "Person" means an individual, partnership, corporation, limited
liability company, limited liability partnership, business trust, joint stock
company, trust, unincorporated association, joint venture or other entity, or a
government or any political subdivision or agency thereof.

       "Plan" means an employee pension benefit plan (other than a
Multiemployer Plan) as defined in Section 3(2) of ERISA currently maintained
by, or to which contributions have been made at any time after December 31,
1984 by, the Guarantor or any ERISA Affiliate of the Guarantor for employees of
the Guarantor or any such ERISA Affiliate and covered by Title IV of ERISA or
subject to the minimum funding standards under Section 412 of the Code.

       "Reference Banks" means NationsBank, CIBC Inc. and Texas Commerce Bank
National Association.

       "Restricted Payment" means, with respect to any Person, (i) any dividend
paid on its capital stock, (ii) any repurchase of its capital stock, or (iii)
any loan or advance or payment of any kind with respect to its capital stock.

       "Restricted Subsidiary" means the Borrower or any other Subsidiary of
the Guarantor which (i) is organized under the laws of the United States or any
state thereof and (ii) has assets with an aggregate book value exceeding
$10,000,000.

       "Revolving Period" means the period of time commencing on the
effectiveness of this Agreement and ending on the Termination Date.

       "S&P" means Standard & Poor's Ratings Services, a division of The
McGraw-Hill Companies, Inc., or any successor thereto.

       "Subsidiary" of any Person means any corporation of which more than 50%
of the outstanding capital stock having ordinary voting power to elect a
majority of the board of directors of such corporation or others performing
similar functions (irrespective of whether or not at the time capital stock of
any other class or classes of such corporation shall or might have voting power
upon the occurrence of any contingency) is at the time directly or indirectly
owned by such Person.

       "Substantial Part" means, with respect to the assets of the Guarantor
and the Restricted Subsidiaries, assets which in the aggregate in any one
fiscal year of the Guarantor exceed 10% of the Consolidated Tangible Net Worth
of the Guarantor and its Subsidiaries.

       "Tangible Net Worth" of any Person means, as of any date of
determination, the excess of total assets of such Person over total
liabilities, total assets and total liabilities each to be determined in
accordance with generally accepted accounting principles, excluding, however,
from the





                                      -11-
<PAGE>   109
determination of total assets (i) patents, patent applications, trademarks,
copyrights and trade names, (ii) goodwill, organizational, experimental,
research and development expense and other like intangibles, (iii) treasury
stock, and (iv) monies set apart and held in a sinking or other analogous fund
established for the purchase, redemption or other retirement of capital stock.

       "Termination Date" means February 27, 2002, or the earlier date of
termination in whole of the Commitments pursuant to Section 2.04 or 8.01.

       "Termination Event" means (i) a "reportable event", as such term is
described in Section 4043 of ERISA (other than a "reportable event" not subject
to the provision for 30-day notice to the PBGC), or an event described in
Section 4062(f) of ERISA, or (ii) the withdrawal of the Guarantor or any ERISA
Affiliate of the Guarantor from a Multiple Employer Plan during a plan year in
which it was a "substantial employer", as such term is defined in Section
4001(a)(2) of ERISA, or the incurrence of liability by the Guarantor or any
ERISA Affiliate of the Guarantor under Section 4064 of ERISA upon the
termination of a Plan or Multiple Employer Plan, or (iii) the distribution of a
notice of intent to terminate a Plan pursuant to Section 4041(a)(2) of ERISA or
the treatment of a Plan amendment as a termination under Section 4041 of ERISA,
or (iv) the institution of proceedings to terminate a Plan by the PBGC under
Section 4042 of ERISA, or (v) any other event or condition which might
constitute grounds under Section 4042 of ERISA for the termination of, or the
appointment of a trustee to administer, any Plan.

       "Type" shall have the meaning set forth in the definition of the term "A
Advance" above.

       "Volumetric Production Payment" means, with respect to any Person, any
obligation of such Person to deliver pre-determined volumes of oil or gas out
of future production from designated reserves that is without recourse to other
assets of such Person.

       "Withdrawal Liability" shall have the meaning given such term under Part
I of Subtitle E of Title IV of ERISA.

       Section 1.02.  Computation of Time Periods.  In this Agreement in the
computation of periods of time from a specified date to a later specified date,
the word "from" means "from and including" and the words "to" and "until" each
means "to but excluding."

       Section 1.03.  Accounting Terms.  All accounting terms not specifically
defined herein shall be construed in accordance with generally accepted
accounting principles, and each reference herein to "generally accepted
accounting principles" shall mean generally accepted accounting principles
consistent with those applied in the preparation of the financial statements
referred to in Section 5.05.

       Section 1.04.  Miscellaneous.  The words "hereof", "herein" and
"hereunder" and words of similar import when used in this Agreement shall refer
to this Agreement as a whole and not to any





                                      -12-
<PAGE>   110
particular provision of this Agreement, and Article, Section, Schedule and
Exhibit references are to Articles and Sections of and Schedules and Exhibits
to this Agreement, unless otherwise specified.


                                   ARTICLE II

                       AMOUNTS AND TERMS OF THE ADVANCES

       Section 2.01.  The A Advances.  Each Bank severally agrees, on the terms
and conditions hereinafter set forth, to make A Advances to the Borrower from
time to time on any Business Day prior to the Termination Date in an aggregate
amount outstanding not to exceed at any time such Bank's Commitment, provided
that the aggregate amount of the Commitments of the Banks shall be deemed used
from time to time to the extent of the aggregate amount of the B Advances then
outstanding and such deemed use of the aggregate amount of the Commitments
shall be applied to the Banks ratably according to their respective Commitments
(such deemed use of the aggregate amount of the Commitments being a "B
Reduction").  Each A Borrowing shall be in an aggregate amount not less than
$5,000,000 or an integral multiple of $1,000,000 in excess thereof, and shall
consist of A Advances of the same Type made to the Borrower on the same day by
the Banks ratably according to their respective Commitments.  Within the limits
of each Bank's Commitment, the Borrower may borrow, prepay pursuant to Section
2.05(b) and reborrow under this Section 2.01.  The indebtedness of the Borrower
resulting from the A Advances made from time to time by each Bank shall be
evidenced by an A Note of the Borrower payable to the order of such Bank.

       Section 2.02.  Making the A Advances.

       (a)    During the Revolving Period, each A Borrowing shall be made on
notice, given not later than 10:00 A.M. (Dallas time) (1) in the case of a
proposed Borrowing comprised of Eurodollar Rate Advances, at least three
Business Days prior to the date of the proposed Borrowing, and (2) in the case
of a proposed Borrowing comprised of Base Rate Advances, on the Business Day of
the proposed Borrowing, by the Borrower requesting such A Borrowing to the
Agent, which shall give to each Bank prompt notice thereof by telecopy, telex
or cable.  Each such notice of an A Borrowing (a "Notice of A Borrowing") shall
be in writing (including by telecopy), in substantially the form of Exhibit B-1
hereto, executed by the Borrower and specifying therein the requested (i) date
of such A Borrowing (which shall be a Business Day), (ii)Type of A Advances
comprising such A Borrowing, (iii) aggregate amount of such A Borrowing, and
(iv)Interest Period for each such A Advance.  In the case of a proposed A
Borrowing comprised of Eurodollar Rate Advances, the Agent shall promptly
notify each Bank of the applicable interest rate under Section 2.06(b).  Each
Bank shall, before 1:00 P.M. (Dallas time) on the date of a proposed A
Borrowing, make available for the account of its Applicable Lending Office to
the Agent at its address referred to in Section 10.02, in same day funds, such
Bank's ratable portion of such A Borrowing.  After the Agent's receipt of such
funds and upon fulfillment of the applicable conditions set forth in Article
III, the Agent will make such funds available to the Borrower at the Agent's
aforesaid address.





                                      -13-
<PAGE>   111
       (b)    Anything in subsection (a) above to the contrary
notwithstanding:

       (i)    at no time shall there be outstanding more than five A Borrowings
              consisting of Eurodollar Rate Advances and one Borrowing
              consisting of Base Rate Advances (other than Borrowings
              consisting of Base Rate Advances as a result of Section
              2.02(b)(iii), (iv), or (v));

       (ii)   the Borrower may not select Eurodollar Rate Advances for any A
              Borrowing to be made if the aggregate amount of such Borrowing is
              less than $20,000,000;

       (iii)  if any Bank shall, at least one Business Day before the date of
              any requested A Borrowing to be made, notify the Agent that the
              introduction of or any change in or in the interpretation of any
              law or regulation makes it unlawful, or that any central bank or
              other governmental authority asserts that it is unlawful, for
              such Bank or its Eurodollar Lending Office to perform its
              obligations hereunder to make Eurodollar Rate Advances or to fund
              Eurodollar Rate Advances hereunder, the right of the Borrower to
              select Eurodollar Rate Advances for such A Borrowing or any
              subsequent A Borrowing shall be suspended until such Bank shall
              notify the Agent that the circumstances causing such suspension
              no longer exist, and, except as provided in Section 2.02(b)(vi),
              each Advance comprising such A Borrowing shall be a Base Rate
              Advance;

       (iv)   if the Majority Banks shall, on or before the date of any
              requested A Borrowing to be made, notify the Agent that the
              Eurodollar Rate for Eurodollar Rate Advances comprising such A
              Borrowing will not adequately reflect the cost to such Banks of
              making their respective Eurodollar Rate Advances for such A
              Borrowing, the right of the Borrower to select Eurodollar Rate
              Advances for such A Borrowing or any subsequent A Borrowing shall
              be suspended until the Agent, at the request of the Majority
              Banks, shall notify the Borrower and the Banks that the
              circumstances causing such suspension no longer exist, and,
              except as provided in Section 2.02(b)(vi), each Advance
              comprising such A Borrowing shall be a Base Rate Advance;

       (v)    if less than two Reference Banks furnish timely information to
              the Agent for determining the Eurodollar Rate for Eurodollar Rate
              Advances, comprising any requested A Borrowing to be made, the
              right of the Borrower to select Eurodollar Rate Advances, as the
              case may be, for such A Borrowing or any subsequent A Borrowing
              shall be suspended until the Agent shall notify the Borrower and
              the Banks that the circumstances causing such suspension no
              longer exist, and, except as provided in Section 2.02(b)(vi),
              each Advance comprising such A Borrowing shall be a Base Rate
              Advance;





                                      -14-
<PAGE>   112
        (vi)  if the Borrower has requested a proposed A Borrowing
              consisting of Eurodollar Rate Advances and as a result of
              circumstances referred to in Section 2.02(b)(iii), (iv) or (v)
              such A Borrowing would not consist of Eurodollar Rate Advances,
              the Borrower may, by notice given not later than 2:00 P.M. (Dallas
              time) at least one Business Day prior to the date such proposed A
              Borrowing would otherwise be made, cancel such A Borrowing, in
              which case such A Borrowing shall be cancelled and no Advances
              shall be made as a result of such requested A Borrowing, but the
              Borrower shall indemnify the Banks in connection with such        
              cancellation as contemplated by Section 2.02(c); and
        
        (vii) if the Borrower shall fail to select the duration or continuation
              of any Interest Period for any Eurodollar Rate Advances in
              accordance with the provisions contained in the definition of
              "Interest Period" in Section 1.01 and this paragraph (b), the
              Agent will promptly so notify the Borrower and the Banks and such
              A Advances will be made available to the Borrower on the date of
              such A Borrowing as Base Rate Advances.

       (c)    Each Notice of A Borrowing shall be irrevocable and binding on
the Borrower, except as set forth in Section 2.02(b)(vi).  In the case of any A
Borrowing requested by the Borrower which the related Notice of A Borrowing
specifies is to be comprised of Eurodollar Rate Advances, the Borrower shall
indemnify each Bank against any loss, cost or expense incurred by such Bank as
a result of any failure to fulfill on or before the date specified in such
Notice of A Borrowing for such A Borrowing the applicable conditions set forth
in Article III, including, without limitation, any loss (including loss of
reasonably anticipated profits), cost or expense incurred by reason of the
liquidation or reemployment of deposits or other funds acquired by such Bank to
fund the A Advance to be made by such Bank as part of such A Borrowing when
such A Advance, as a result of such failure, is not made on such date.  A
certificate in reasonable detail as to the basis for and the amount of such
loss, cost or expense submitted to the Borrower and the Agent by such Bank
shall be prima facie evidence of the amount of such loss, cost or expense.  If
an A Borrowing requested by the Borrower which the related Notice of A
Borrowing specifies is to be comprised of Eurodollar Rate Advances is not made
as an A Borrowing comprised of Eurodollar Rate Advances as a result of Section
2.02(b), the Borrower shall indemnify each Bank against any loss (excluding
loss of profits), cost or expense incurred by such Bank by reason of the
liquidation or reemployment of deposits or other funds acquired by such Bank
(prior to the time such Bank is actually aware that such A Borrowing will not
be so made) to fund the A Advance to be made by such Bank as part of such A
Borrowing.  A certificate in reasonable detail as to the basis for and the
amount of such loss, cost or expense submitted to the Borrower and the Agent by
such Bank shall be prima facie evidence of the amount of such loss, cost or
expense.

       (d)    With respect to any new A Borrowing to be made on the last day of
an Interest Period, the Borrower and each Bank agree that any amounts payable
by the Borrower to such Bank in connection with maturing A Advances on the date
of such Borrowing shall be netted against the amount of the new Borrowing to be
funded by such Bank so as to eliminate where possible the need for actual
payment and readvancement of funds by the parties.  In the event of any A
Borrowing





                                      -15-
<PAGE>   113
subject to the conditions precedent in Section 3.03, unless the Agent shall
have received notice from a Bank prior to the date of any A Borrowing that such
Bank will not make available to the Agent such Bank's ratable portion of such A
Borrowing (to the extent in excess of any maturing A Advances payable to such
Bank), the Agent may assume that such Bank has made such portion available to
the Agent on the date of such A Borrowing in accordance with subsection (a) of
this Section 2.02 and the Agent may, in reliance upon such assumption, make
available to the Borrower requesting such A Borrowing on such date a
corresponding amount.  If and to the extent that such Bank shall not have so
made such ratable portion available to the Agent, such Bank and the Borrower
severally agree to repay to the Agent forthwith on demand such corresponding
amount together with interest thereon, for each day from the date such amount
is made available to the Borrower until the date such amount is repaid to the
Agent, at (i) in the case of the Borrower, the interest rate applicable at the
time to A Advances comprising such A Borrowing and (ii) in the case of such
Bank, the Federal Funds Rate.  If such Bank shall repay to the Agent such
corresponding amount, such amount so repaid shall constitute such Bank's A
Advance as part of such A Borrowing for purposes of this Agreement.

       (e)    The failure of any Bank to make the A Advance to be made by it as
part of any A Borrowing shall not relieve any other Bank of its obligation, if
any, hereunder to make its A Advance on the date of such A Borrowing, but no
Bank shall be responsible for the failure of any other Bank to make the A
Advance to be made by such other Bank on the date of any A Borrowing.

       Section 2.03.  Fees.
       
       (a)    Facility Fee.  The Borrower agrees to pay to each Bank a
facility fee calculated on the amount of such Bank's Commitment (regardless of
usage) from the date hereof until the Termination Date at the Applicable
Facility Fee per annum, payable in arrears on the last day of each calendar
quarter during the term of such Bank's Commitment, and on the Termination Date.

       (b)    Administrative Fee.  The Borrower agrees to pay to the Agent, for
its sole account, an administrative fee as set forth in the Agent's Fee Letter.

       (c)    Bid Request Fee.  The Borrower agrees to pay to the Agent on the
date of each request for B Advances pursuant to Section 2.08 a bid request fee
as set forth in the Agent's Fee Letter.

       (d)    Arrangement Fee.  The Borrower agrees to pay to the Agent on the
date of this Agreement an arrangement fee as set forth in the Agent's Fee
Letter.

       Section 2.04.  Optional Reduction of the Commitments.  The Borrower
shall have the right, upon at least five Business Days notice to the Agent, to
terminate in whole or reduce ratably in part the unused portions of the
respective Commitments of the Banks, provided that each partial reduction shall
be in the aggregate amount of at least $10,000,000, and provided further, that
the aggregate amount of the Commitments of the Banks shall not be reduced to an
amount which is less





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than the aggregate principal amount of the Advances then outstanding.  Any such
reduction or termination of the Commitments shall be permanent.

       Section 2.05.  Repayment and Prepayment of A Advances.  (a) The unpaid
principal amount of each A Advance that is made by each Bank shall be repaid by
the Borrower in full on the last day of the Interest Period for such A Advance.


       (b)    The Borrower may, in respect of Base Rate Advances upon at least
one Business Days' notice, and, in respect of Eurodollar Rate Advances upon at
least three Business Days' notice, to the Agent stating the proposed date
(which shall be a Business Day) and aggregate principal amount of the
prepayment, and if such notice is given the Borrower shall, prepay the
outstanding principal amounts of the A Advances comprising part of the same A
Borrowing in whole or ratably in part, together with accrued interest to the
date of such prepayment on the principal amount prepaid and amounts, if any,
required to be paid pursuant to Section 2.10 as a result of such prepayment;
provided, however, that each partial prepayment pursuant to this Section
2.05(b) shall be in an aggregate principal amount not less than $5,000,000 and
in an aggregate principal amount such that after giving effect thereto no A
Borrowing comprised of Base Rate Advances shall have a principal amount
outstanding of less than $5,000,000 and no A Borrowing comprised of Eurodollar
Rate Advances shall have a principal amount outstanding of less than
$20,000,000.

       Section 2.06.  Interest on A Advances.  The Borrower shall pay interest
on the unpaid principal amount of each A Advance made by each Bank from the
date of such A Advance until such principal amount shall be paid in full, at
the following rates per annum:

       (a)    Base Rate Advances.  If such A Advance is a Base Rate Advance, a
rate per annum equal at all times during the Interest Period for such A Advance
to the Base Rate in effect from time to time during such Interest Period for
such A Advance, payable on the last day of such Interest Period.

       (b)    Eurodollar Rate Advances.  If such A Advance is a Eurodollar Rate
Advance, a rate per annum equal at all times during the Interest Period for
such A Advance to the sum of the Eurodollar Rate for such Interest Period plus
the Applicable Margin in effect from time to time for such A Advance, payable
on the last day of such Interest Period and, if such Interest Period has a
duration of more than three months, on each day which occurs during such
Interest Period every three months from the first day of such Interest Period.

       (c)    Additional Interest on Eurodollar Rate Advances.  The Borrower
shall pay to each Bank, so long as such Bank shall be required under
regulations of the Board of Governors of the Federal Reserve System to maintain
reserves with respect to liabilities or assets consisting of or including
Eurocurrency Liabilities, additional interest on the unpaid principal amount of
each Eurodollar Rate Advance of such Bank, from the date of such Advance until
such principal amount is paid in full, at an interest rate per annum equal at
all times to the remainder obtained by subtracting (i) the Eurodollar Rate for
the Interest Period for such Advance from (ii) the rate obtained





                                      -17-
<PAGE>   115
by dividing such Eurodollar Rate by a percentage equal to 100% minus the
Eurodollar Rate Reserve Percentage of such Bank for such Interest Period,
payable on each date on which interest is payable on such Advance.  Such
additional interest shall be determined by such Bank and notified to the
Borrower through the Agent.  A certificate as to the amount of such additional
interest submitted to the Borrower and the Agent by such Bank shall be
conclusive and binding for all purposes, absent manifest error.

       Section 2.07.  Interest Rate Determination.  (a) Each Reference Bank
agrees to furnish to the Agent timely information for the purpose of
determining each Eurodollar Rate.  If any of the Reference Banks shall not
furnish such timely information to the Agent for the purpose of determining any
such Eurodollar Rate, the Agent shall determine such Eurodollar Rate on the
basis of timely information furnished by the remaining Reference Banks, subject
to Section 2.02(b).

       (b)    The Agent shall give prompt notice to the Borrower and the Banks
of the applicable interest rate for such A Advance determined by the Agent for
purposes of Section 2.06(a) or (b), and the applicable rate, if any, furnished
by each Reference Bank for the purpose of determining the applicable interest
rate under Section 2.06(b).

       Section 2.08.  The B Advances.
       
       (a) Each Bank severally agrees that the Borrower may make B Borrowings
under this Section 2.08 from time to time on any Business Day during the period
from the date hereof until the date occurring 30 days prior to the Termination
Date in the manner set forth below; provided that, following the making of each
B Borrowing, the aggregate amount of the Advances then outstanding shall not
exceed the aggregate amount of the Commitments of the Banks (computed without
regard to any B Reduction).

       (i)    The Borrower may request a B Borrowing under this Section 2.08 by
              delivering to the Agent, not later than 9:00 A.M. (Dallas time)
              at least five Business Days prior to the date of the proposed B
              Borrowing, a notice of a B Borrowing (a "Notice of B Borrowing"),
              in substantially the form of Exhibit B-2 hereto, specifying the
              date and aggregate amount of the proposed B Borrowing, the
              maturity date for repayment of each B Advance to be made as part
              of such B Borrowing (which maturity date may not be earlier than
              the date occurring 14 days after the date of such B Borrowing or
              later than the earlier of 6 months after the date of such B
              Borrowing or the Termination Date), the interest payment date or
              dates relating thereto, and any other terms to be applicable to
              such B Borrowing (including, without limitation, the basis to be
              used by the Banks in determining the rate or rates of interest to
              be offered by them as provided in paragraph (ii) below and
              prepayment terms, if any, but excluding any waiver or other
              modification to any of the conditions set forth in Article III).
              The Borrower may not select a maturity date for any B Borrowing
              which ends after the Termination Date.  The Agent shall promptly
              notify each Bank of each request





                                      -18-
<PAGE>   116
              for a B Borrowing received by it from the Borrower by sending
              such Bank a copy of the related Notice of B Borrowing.

       (ii)   Each Bank may, if in its sole discretion it elects to do so,
              irrevocably offer to make one or more B Advances to the Borrower
              as part of such proposed B Borrowing at a rate or rates of
              interest specified by such Bank in its sole discretion, by
              notifying the Agent (which shall give prompt notice thereof to
              the Borrower), before 9:00 A.M. (Dallas time) three Business Days
              before the date of such proposed B Borrowing specified in the
              Notice of B Borrowing delivered with respect thereto pursuant to
              paragraph (i) above, of the minimum amount and maximum amount of
              each B Advance which such Bank would be willing to make as part
              of such proposed B Borrowing (which amounts may, subject to the
              proviso to the first sentence of this Section 2.08(a), exceed
              such Bank's Commitment), the rate or rates of interest therefor
              and such Bank's Applicable Lending Office with respect to such B
              Advance; provided that if the Agent in its capacity as a Bank
              shall, in its sole discretion, elect to make any such offer, it
              shall notify the Borrower of such offer before 8:45 A.M. (Dallas
              time) three Business Days before the date of the proposed B
              Borrowing specified in the Notice of B Borrowing delivered with
              respect thereto pursuant to paragraph (i) above.  Any Bank which
              has not notified the Agent of an offer prior to the time
              specified above shall be deemed to have elected not to make such
              an offer.

       (iii)  The Borrower shall, in turn, before 10:00 A.M. (Dallas time)
              three Business Days before the date of such proposed B Borrowing
              specified in the Notice of B Borrowing delivered with respect
              thereto pursuant to paragraph (i) above, either

                     (A)    cancel such B Borrowing by giving the Agent notice
                            to that effect, or

                     (B)    accept one or more of the offers made by any Bank
              or Banks pursuant to paragraph (ii) above, in its sole
              discretion, by giving notice to the Agent of the amount of each B
              Advance (which amount shall be equal to or greater than the
              minimum amount, and equal to or less than the maximum amount,
              notified to the Borrower by the Agent on behalf of such Bank for
              such B Advance pursuant to paragraph (ii) above) to be made by
              each Bank as part of such B Borrowing, and reject any remaining
              offers made by Banks pursuant to paragraph (ii) above by giving
              the Agent notice to that effect.

       (iv)   If the Borrower notifies the Agent that such B Borrowing is
              cancelled pursuant to paragraph (iii)(A) above, the Agent shall
              give prompt notice thereof to the Banks and such B Borrowing
              shall not be made.

       (v)    If the Borrower accepts one or more of the offers made by any
              Bank or Banks pursuant to paragraph (iii)(B) above, the Agent
              shall in turn promptly notify (A) each Bank that has made an
              offer as described in paragraph (ii) above, of the date and





                                      -19-
<PAGE>   117
       aggregate amount of such B Borrowing and whether or not any offer or
       offers made by such Bank pursuant to paragraph (ii) above have been
       accepted by the Borrower, (B) each Bank that is to make a B Advance as
       part of such B Borrowing, of the amount of each B Advance to be made by
       such Bank as part of such B Borrowing, and (C) each Bank that is to make
       a B Advance as part of such B Borrowing, upon receipt, that the Agent
       has received forms of documents appearing to fulfill the applicable
       conditions set forth in Article III.  Each Bank that is to make a B
       Advance as part of such B Borrowing shall, before 1:00 P.M. (Dallas
       time) on the date of such B Borrowing specified in the notice received
       from the Agent pursuant to clause (A) of the preceding sentence or any
       later time when such Bank shall have received notice from the Agent
       pursuant to clause (C) of the preceding sentence, make available for the
       account of its Applicable Lending Office to the Agent at its address
       referred to in Section 10.02 such Bank's portion of such B Borrowing, in
       same day funds.  Upon fulfillment of the applicable conditions set forth
       in Article III and after receipt by the Agent of such funds, the Agent
       will make such funds available to the Borrower at the Agent's aforesaid
       address.  Promptly after each B Borrowing the Agent will notify each
       Bank of the amount of the B Borrowing, the consequent B Reduction and
       the dates upon which such B Reduction commenced and will terminate.

       (b)    Each B Borrowing shall be in an aggregate amount of not less than
$5,000,000 or an integral multiple of $1,000,000 in excess thereof and,
following the making of each B Borrowing, the Borrower shall be in compliance
with the limitation set forth in the proviso to the first sentence of Section
2.08(a).

       (c)    Within the limits and on the conditions set forth in this Section
2.08, the Borrower may from time to time borrow under this Section 2.08, repay
pursuant to subsection (d) below, and reborrow under this Section 2.08,
provided that no B Borrowing shall be made within three Business Days of the
date of another B Borrowing.

       (d)    The Borrower shall repay to the Agent for the account of each
Bank which has made a B Advance to the Borrower on the maturity date of each B
Advance (such maturity date being that specified by the Borrower for repayment
of such B Advance in the related Notice of B Borrowing delivered pursuant to
subsection (a)(i) above) the then unpaid principal amount of such B Advance.
The Borrower shall not have any right to prepay any principal amount of any B
Advance unless, and then only on the terms, specified by the Borrower for such
B Advance in the related Notice of B Borrowing delivered pursuant to subsection
(a)(i) above and set forth in the B Note evidencing such B Advance.

       (e)    The Borrower shall pay interest on the unpaid principal amount of
each B Advance from the date of such B Advance to the date the principal amount
of such B Advance is repaid in full, at the rate of interest for such B Advance
specified by the Bank making such B Advance in its notice with respect thereto
delivered pursuant to subsection (a)(ii) above, payable on the interest





                                      -20-
<PAGE>   118
payment date or dates specified by the Borrower for such B Advance in the
related Notice of B Borrowing delivered pursuant to subsection (a)(i) above, as
provided in the B Note evidencing such B Advance.

       (f)    The indebtedness of the Borrower resulting from each B Advance
made to the Borrower as part of a B Borrowing shall be evidenced by a separate
B Note of the Borrower payable to the order of the Bank making such B Advance.

       Section 2.09.  Payments, Computations; Interest on Overdue Amounts.
       
       (a) The Borrower shall make each payment hereunder and under the Notes
to be made by it not later than 10:00 A.M. (Dallas time) on the day when due in
U.S. dollars to the Agent at its address referred to in Section 10.02 in same
day funds.  The Agent will promptly thereafter cause to be distributed like
funds relating to the payment of principal, interest or fees ratably (other
than amounts payable pursuant to Section 2.06(c), 2.08, 2.10, 2.11 or 2.13) to
the Banks for the account of their respective Applicable Lending Offices, and
like funds relating to the payment of any other amount payable to any Bank to
such Bank for the account of its Applicable Lending Office, in each case to be
applied in accordance with the terms of this Agreement.  In no event shall any
Bank be entitled to share any administrative fee paid to the Agent pursuant to
Section 2.03(b), any bid request fee paid to the Agent pursuant to Section
2.03(c) or any other fee paid to the Agent, as such.

       (b)    All computations of interest based on the Base Rate and of fees
shall be made by the Agent on the basis of a year of 365 or 366 days, as the
case may be, and all computations of interest based on the Eurodollar Rate or
the Federal Funds Rate shall be made by the Agent, and all computations of
interest pursuant to Section 2.06(c) shall be made by a Bank, on the basis of a
year of 360 days, in each case for the actual number of days (including the
first day but excluding the last day) occurring in the period for which such
interest or fees are payable.  Each determination by the Agent (or, in the case
of Section 2.06(c), by a Bank) of an interest rate hereunder shall be
conclusive and binding for all purposes, absent manifest error.

       (c)    Whenever any payment hereunder or under the Notes shall be stated
to be due on a day other than a Business Day, such payment shall be made on the
next succeeding Business Day, and such extension of time shall in such case be
included in the computation of payment of interest or fee, as the case may be;
provided, however, if such extension would cause payment of interest on or
principal of Eurodollar Rate Advances to be made in the next following calendar
month, such payment shall be made on the next preceding Business Day.

       (d)    Unless the Agent shall have received notice from the Borrower
prior to the date on which any payment is due by the Borrower to any Bank
hereunder that the Borrower will not make such payment in full, the Agent may
assume that the Borrower has made such payment in full to the Agent on such
date and the Agent may, in reliance upon such assumption, cause to be
distributed to each Bank on such due date an amount equal to the amount then
due such Bank.  If and to the extent the Borrower shall not have so made such
payment in full to the Agent, each Bank shall repay





                                      -21-
<PAGE>   119
to the Agent forthwith on demand such amount distributed to such Bank together
with interest thereon, for each day from the date such amount is distributed to
such Bank until the date such Bank repays such amount to the Agent, at the
Federal Funds Rate.

       (e)    Whenever any reference is made to any Bank's "ratable share" or
"ratable portion" (or any similar reference) of any amount hereunder, such
share or portion shall be calculated to not more than four decimal places,
rounding up or down, as appropriate.

       (f)    Any amount payable hereunder or under the Notes or under any
other Credit Document which is not paid when due (whether at stated maturity,
by acceleration or otherwise) shall bear interest, to the extent permitted by
law, from the date on which such amount became due until such amount is paid in
full, payable on demand, at a rate per annum equal at all times to:  (i) in the
case of any overdue principal of any Advance, the greater of (x) the sum of the
Base Rate in effect from time to time plus 2% per annum and (y) the sum of the
rate per annum required to be paid on such Advance immediately prior to the
date on which such amount became due plus 2% per annum, or (ii) in the case of
any interest, fee or other amount payable hereunder or under the Notes or under
any other Credit Document, the sum of the Base Rate in effect from time to time
plus 2% per annum.

       Section 2.10.  Consequential Losses.  If (a) any payment (or purchase
pursuant to Section 2.11(c)) of principal of any Eurodollar Rate Advance or B
Advance made to the Borrower is made other than on the last day of an Interest
Period relating to such Advance (or in the case of a B Advance, other than on
the original scheduled maturity date thereof), as a result of a prepayment
pursuant to Section 2.05(b) or 2.12 or acceleration of the maturity of the
Notes pursuant to Section 2.15 or Section 8.01 or for any other reason or as a
result of any such purchase; or (b) the Borrower fails to make a principal or
interest payment with respect to any Eurodollar Rate Advance or B Advance on
the date such payment is due and payable, the Borrower shall, upon demand by
any Bank (with a copy of such demand to the Agent), pay to the Agent for the
account of such Bank any amounts required to compensate such Bank for any
additional losses, costs or expenses which it may reasonably incur as a result
of any such payment or purchase, including, without limitation, any loss
(including loss of reasonably anticipated profits, except in the case of such a
purchase pursuant to Section 2.11(c)), cost or expense incurred by reason of
the liquidation or reemployment of deposits or other funds acquired by such
Bank to fund or maintain such Advance.

       Section 2.11.  Increased Costs.
       (a) If, due to either (i) the introduction of or any change (including
without limitation, but without duplication, any change by way of imposition or
increase of reserve requirements included, in the case of Eurodollar Rate
Advances, the Eurodollar Rate Reserve Percentage) in or in the interpretation,
application or applicability of any law or regulation or (ii) the compliance
with any guideline or request from any central bank or other governmental
authority (whether or not having the force of law), there shall be any increase
in the cost to any Bank of agreeing to make or making, funding or maintaining
any Fixed Rate Advance to the Borrower, then the Borrower shall from time





                                      -22-
<PAGE>   120
to time, upon demand by such Bank (with a copy of such demand to the Agent),
pay to the Agent for the account of such Bank additional amounts sufficient to
compensate such Bank for such increased cost.  A certificate as to the amount
of such increased cost, submitted to the Borrower and the Agent by such Bank,
shall be prima facie evidence of the amount of such increased cost.  Promptly
after any Bank becomes aware of any such introduction, change or proposed
compliance, such Bank shall notify the Borrower thereof, provided that the
failure to provide such notice shall not affect such Bank's rights hereunder,
except that such Bank's right to recover such increased costs from the Borrower
for any period prior to such notice shall be limited to the period of (i) 180
days, if such increased cost relates to any outstanding Advance, or (ii) 90
days, in each other event, immediately prior to the date such notice is given
to the Borrower.

       (b)    If any Bank determines that compliance with any law or regulation
or any guideline or request from any central bank or other governmental
authority (whether or not having the force of law) affects or would affect the
amount of capital required or expected to be maintained by such Bank or any
corporation controlling such Bank and that the amount of such capital is
increased by or based upon the existence of such Bank's commitment to lend to
the Borrower hereunder and other commitments of this type, then, upon demand by
such Bank (with a copy of such demand to the Agent), the Borrower shall
immediately pay to the Agent for the account of such Bank, from time to time as
specified by such Bank, additional amounts sufficient to compensate such Bank
or such corporation in the light of such circumstances, to the extent that such
Bank reasonably determines such increase in capital to be allocable to the
existence of such Bank's commitment to lend hereunder.  A certificate as to
such amounts submitted to the Borrower and the Agent by such Bank shall be
conclusive and binding for all purposes, absent manifest error.

       (c)    In the event that any Bank makes a demand for payment under
Section 2.06(c) or this Section 2.11, the Borrower may within ninety days of
such demand, if no Default then exists, replace such Bank with another
commercial bank in accordance with all of the provisions of the last sentence
of Section 10.06(a) (including execution of an appropriate Assignment) provided
that (i) all obligations of such Bank to lend hereunder shall be terminated and
the A Note and any B Note payable to such Bank and all other obligations owed
to such Bank hereunder shall be purchased in full without recourse at par plus
accrued interest at or prior to such replacement, (ii) such replacement bank
shall be reasonably satisfactory to the Agent, (iii) such replacement bank
shall, from and after such replacement, be deemed for all purposes to be a
"Bank" hereunder with a Commitment in the amount of the respective Commitment
of the assigning Bank immediately prior to such replacement (plus, if such
replacement bank is already a Bank prior to such replacement, the respective
Commitment of such Bank prior to such replacement), as such amount may be
changed from time to time pursuant hereto, and shall have all of the rights,
duties and obligations hereunder of the Bank being replaced, and (iv) such
other actions shall be taken by the Borrower, such Bank and such replacement
bank as may be appropriate to effect the replacement of such Bank with such
replacement bank on terms such that such replacement bank has all of the
rights, duties and obligations hereunder as such Bank (including, without
limitation, execution and delivery of new Notes to such replacement bank,
redelivery to the Borrower in due course of the Notes payable to





                                      -23-
<PAGE>   121
such Bank and specification of the information contemplated by Schedule I as to
such replacement bank).

       Section 2.12.  Illegality.  Notwithstanding any other provision of this
Agreement, if any Bank shall notify the Agent that the introduction of or any
change in or in the interpretation of any law or regulation shall make it
unlawful, or any central bank or other governmental authority shall assert that
it is unlawful, for any Bank or its Applicable Lending Office to make any Fixed
Rate Advance or to continue to fund or maintain any Fixed Rate Advance
hereunder, then, on notice thereof to the Borrower by the Agent, (i) the
obligation of each of the Banks to make any Fixed Rate Advance of the same Type
shall be suspended until the Agent shall notify the Borrower and the Banks that
the circumstances causing such suspension no longer exist, and (ii) the
Borrower shall forthwith prepay in full all Fixed Rate Advances then
outstanding of all Banks which are affected Fixed Rate Advances, together with
all accrued interest thereon and all amounts payable pursuant to Section 2.10,
unless each Bank shall determine in good faith in its sole opinion that it is
lawful to maintain the Fixed Rate Advances made by such Bank to the end of the
Interest Period then applicable thereto.

       Section 2.13.  Taxes.
       
       (a) Any and all payments by the Borrower or the Guarantor hereunder or
under the Notes or any other Credit Document shall be made, in accordance with
Section 2.09, free and clear of and without deduction for any and all present
or future taxes, levies, imposts, deductions, charges or withholdings with
respect thereto, and all liabilities with respect thereto, excluding in the
case of each Bank and the Agent, taxes imposed on its income, and franchise
taxes imposed on it, by the jurisdiction under the laws of which such Bank or
the Agent (as the case may be) is organized or any political subdivision
thereof and, in the case of each Bank, taxes imposed on its income, and
franchise taxes imposed on it, by the jurisdiction of such Bank's Applicable
Lending Office or any political subdivision thereof (all such non-excluded
taxes, levies, imposts, deductions, charges, withholdings and liabilities being
hereinafter referred to as "Taxes").  If the Borrower or the Guarantor shall be
required by law to deduct any Taxes from or in respect of any sum payable by it
hereunder or under any Note or other Credit Document to any Bank or the Agent,
(i) the sum payable shall be increased as may be necessary so that after making
all required deductions (including deductions applicable to additional sums
payable under this Section 2.13) such Bank or the Agent (as the case may be)
receives an amount equal to the sum it would have received had no such
deductions been made, (ii) the Borrower or the Guarantor, as the case may be,
shall make such deductions and (iii) the Borrower or the Guarantor, as the case
may be, shall pay the full amount deducted to the relevant taxation authority
or other authority in accordance with applicable law.

       (b)    In addition, the Borrower or the Guarantor, as the case may be,
agrees to pay any present or future stamp or documentary taxes or any other
excise or property taxes, charges or similar levies which arise from any
payment made by the Borrower or the Guarantor hereunder or under any Note or
other Credit Document executed by it or from the execution, delivery or





                                      -24-
<PAGE>   122
registration of, or otherwise with respect to, this Agreement or any Note or
other Credit Document (hereinafter referred to as "Other Taxes").

       (c)    THE BORROWER AND THE GUARANTOR WILL INDEMNIFY EACH BANK, EACH CO-
AGENT, THE ARRANGER & SYNDICATION AGENT AND THE AGENT FOR THE FULL AMOUNT OF
TAXES OR OTHER TAXES (INCLUDING, WITHOUT LIMITATION, ANY TAXES OR OTHER TAXES
IMPOSED BY ANY JURISDICTION ON AMOUNTS PAYABLE UNDER THIS SECTION 2.13) OWED
AND PAID BY SUCH BANK, SUCH CO-AGENT, THE ARRANGER & SYNDICATION AGENT OR THE
AGENT (AS THE CASE MAY BE) AND ANY LIABILITY (INCLUDING PENALTIES, INTEREST AND
EXPENSES) ARISING THEREFROM OR WITH RESPECT THERETO.  THIS INDEMNIFICATION
SHALL BE MADE WITHIN 30 DAYS FROM THE DATE SUCH BANK, SUCH CO-AGENT, THE
ARRANGER & SYNDICATION AGENT OR THE AGENT (AS THE CASE MAY BE) MAKES WRITTEN
DEMAND THEREFOR.

       (d)    Within 30 days after the date of the payment of Taxes by or at
the direction of the Borrower or the Guarantor, the Borrower will furnish to
the Agent, at its address referred to in Section 10.02, the original or a
certified copy of a receipt evidencing payment thereof.

       (e)    Without prejudice to the survival of any other agreement of the
Borrower or the Guarantor hereunder, the agreements and obligations of the
Borrower and the Guarantor contained in this Section 2.13 shall survive the
payment in full of principal and interest hereunder and under the Notes and
other Credit Documents.

       (f)    Each Bank that is not incorporated under the laws of the United
States of America or a state thereof agrees that it will deliver to the
Borrower and the Agent on the date of this Agreement or upon the effectiveness
of any Assignment and Acceptance (i) two duly completed copies of United States
Internal Revenue Service Form 1001 or 4224 or successor applicable form, as the
case may be, certifying in each case that such Bank is entitled to receive
payments under this Agreement and the Notes payable to it, without deduction or
withholding of any United States federal income taxes, (ii) if applicable, an
Internal Revenue Service Form W-8 or W-9 or successor applicable form, as the
case may be, to establish an exemption from United States backup withholding
tax, and (iii) any other governmental forms which are necessary or required
under an applicable tax treaty or otherwise by law to reduce or eliminate any
withholding tax, which have been reasonably requested by the Borrower.  Each
Bank which delivers to the Borrower and the Agent a Form 1001 or 4224 and Form
W-8 or W-9 pursuant to the next preceding sentence further undertakes to
deliver to the Borrower and the Agent two further copies of the said Form 1001
or 4224 and Form W-8 or W-9, or successor applicable forms, or other manner of
certification, as the case may be, on or before the date that any such form
expires or becomes obsolete or after the occurrence of any event requiring a
change in the most recent form previously delivered by it to the Borrower and
the Agent, and such extensions or renewals thereof as may reasonably be
requested by the Borrower and the Agent certifying in the case of a Form 1001
or 4224 that such Bank is





                                      -25-
<PAGE>   123
entitled to receive payments under this Agreement without deduction or
withholding of any United States federal income taxes.  The Borrower shall
withhold tax at the rate and in the manner required by the laws of the United
States with respect to payments made to a Bank failing to timely provide the
requisite Internal Revenue Service forms.

       Section 2.14.  Payments Pro Rata.  Except as provided in Sections
2.03(b), 2.03(c), 2.03(d), 2.06(c), 2.10, 2.11, or 2.13, each of the Banks
agrees that if it should receive any payment (whether by voluntary payment, by
realization upon security, by the exercise of the right of setoff or banker's
lien, by counterclaim or cross action, by the enforcement of any right under
this Agreement or the Notes or other Credit Documents, or otherwise) in respect
of any obligation of the Borrower or Guarantor hereunder or under the Notes or
other Credit Documents of a sum which with respect to the related sum or sums
received by other Banks is in a greater proportion than the total amount of
principal, interest, fees or any other obligation incurred hereunder, as the
case may be, then owed and due to such Bank bears to the total amount of
principal, interest, fees or any such other obligation then owed and due to all
of the Banks immediately prior to such receipt, then such Bank receiving such
excess payment shall purchase for cash without recourse from the other Banks an
interest in the obligations of the Borrower to such Banks in such amount as
shall result in a proportional participation by all of the Banks in the
aggregate unpaid amount of principal, interest, fees or any such other
obligation, as the case may be, owed to all of the Banks, provided that if all
or any portion of such excess payment is thereafter recovered from such
purchasing Bank, such purchase from each other Bank shall be rescinded and each
such other Bank shall repay to the purchasing Bank the purchase price to the
extent of such other Bank's ratable share (according to the proportion of (i)
the amount of the participation purchased from such other Bank as a result of
such excess payment to (ii) the total amount of such excess payment) of such
recovery together with an amount equal to such other Bank's ratable share
(according to the proportion of (i) the amount of such other Bank's required
repayment to (ii) the total amount so recovered from the purchasing Bank) of
any interest or other amount paid or payable by the purchasing Bank in respect
of the total amount so recovered.  The Borrower agrees that any Bank so
purchasing a participation from another Bank pursuant to this Section 2.14 may,
to the fullest extent permitted by law, exercise all its rights of payment
(including the right of set-off) with respect to such participation as fully as
if such Bank were the direct creditor of the Borrower in the amount of such
participation.

       Section 2.15. Increase of Aggregate Commitments.  Provided no Default
has occurred and is continuing, the Borrower may by written notice to the Agent
and the Banks request that the aggregate amount of the Commitments hereunder be
increased up to the Aggregate Commitment Limit; provided, however that in the
event the Parallel Agreement is still in effect, (a) the Borrower shall
simultaneously request a pro rata increase in the aggregate amount of the
Parallel Agreement Commitments pursuant to Section 2.15 of the Parallel
Agreement, and (b) after giving effect to such increase of the aggregate
Commitments and such pro rata increase of the aggregate Parallel Agreement
Commitments, the total amount of all Commitments and all Parallel Agreement
Commitments shall not exceed the Aggregate Commitment Limit.  Upon the
Borrower's receipt of (a) incremental commitments from such Banks that may
agree to provide an increased Commitment hereunder, and if the Parallel
Agreement is still in effect, an increased Parallel Agreement





                                      -26-
<PAGE>   124
Commitment under the Parallel Agreement (there being no obligation on the part
of any Bank at any time hereunder to increase such Bank's Commitment or such
Bank's Parallel Agreement Commitment but any such increase agreed upon by any
Bank to be pro rata between this Agreement and the Parallel Agreement so that
its ratable percentage of each is the same) and/or (b) commitments from new
lenders willing to become a Bank with a Commitment hereunder, and if the
Parallel Agreement is still in effect, a "Bank" under the Parallel Agreement
with a pro rata Parallel Agreement Commitment, then such increase of the
aggregate Commitments shall become effective simultaneously with any such
increase of the aggregate Parallel Agreement Commitments when the following
conditions precedent and, if applicable, the conditions precedent set forth in
Section 2.15 of the Parallel Agreement have been satisfied and the Agent shall
have notified the parties hereto to such effect:

       (i)    The Borrower shall have delivered to the Agent, with sufficient
copies for each Bank (A) a certificate of the Chief Financial Officer of the
Borrower addressed to the Banks to the effect that, to the best of such
officer's knowledge, (x) no Default or Event of Default has occurred and is
continuing (or would result from the incurrence of the additional Debt
contemplated by this Section 2.15), and (y) all representations and warranties
herein or in any other Credit Document are true and correct in all material
respects with the same effect as if these representations and warranties had
been made on the date of such certificate (it being understood and agreed that
any representation which by its terms is made as of a specified date shall be
required to be true and correct in all material respects only as of such
specified date), and (B) unless the documentation delivered in connection with
the effectiveness of this Agreement otherwise authorizes Debt hereunder and
under the Parallel Agreement in an aggregate amount up to the Aggregate
Commitment Limit, a certificate of the Borrower's Secretary certifying that the
Borrower has been duly authorized by resolution of the Borrower's Board of
Directors to incur Debt hereunder and, if the Parallel Agreement is still in
effect, under the Parallel Agreement in an amount equal to or exceeding the
increased aggregate amount of the Commitments and, if the Parallel Agreement is
still in effect, the Parallel Agreement Commitments.

       (ii)   An Accession Agreement for each New Bank shall have been duly
executed by each party thereto.

       (iii)  The Agent has received the written consent of each Bank which has
agreed to increase  its Commitment hereunder (but no other Bank's consent shall
be required), such consent to be substantially in the form of the Consent to
Increase of Commitment attached as Exhibit G.

       (iv)    New Notes (including without limitation substitute Notes for
those Banks which have agreed to increase their respective Commitments) shall
have been executed and delivered by the Borrower in substantially the form of
Exhibits A-1 and A-2, as appropriate.

       (v)     No A Advances are outstanding hereunder as of the date such
increase is to become effective, or any such Advances are contemporaneously
repaid on such date.





                                      -27-
<PAGE>   125
                                  ARTICLE III

                                   CONDITIONS

       Section 3.01.  Conditions Precedent to Effectiveness.  This Agreement
shall become effective when the following conditions precedent have been
satisfied and the Agent shall have notified the parties hereto in writing that
this Agreement has become effective pursuant to this Section:

       (a)    Documentation.  The Agent shall have received the following duly
executed by all the parties thereto, in form and substance satisfactory to the
Agent and the Banks, and (except for the Notes) in sufficient copies for each
Bank:

              (i)    This Agreement duly executed by the Borrower, the
       Guarantor, the Agent, the Co-Agents, the Arranger & Syndication Agent
       and each Bank, and an A Note payable to each Bank duly executed by the
       Borrower.

              (ii)   A certificate of the Secretary or an Assistant Secretary
       of the Borrower certifying (i) copies of the Certificate of
       Incorporation and Bylaws of the Borrower as in effect on the date
       hereof, and (ii) the names and true signatures of the officers of the
       Borrower authorized to sign the Credit Documents executed or to be
       executed by the Borrower.

              (iii)  A certificate of the Secretary or an Assistant Secretary
       of the Guarantor certifying (i) copies of the Certificate of
       Incorporation and Bylaws of the Guarantor as in effect on the date
       hereof, and (ii) the names and true signatures of the officers of the
       Guarantor authorized to sign the Credit Documents executed or to be
       executed by the Guarantor.

              (iv)   A favorable opinion of Cullen M. Godfrey, General Counsel
       for each of the Borrower and the Guarantor, substantially in the form of
       Exhibit D hereto and as to such other matters as any Bank through the
       Agent may reasonably request.

              (v)    A favorable opinion of Messrs. Bracewell & Patterson,
       L.L.P. counsel for the Agent, substantially in the form of Exhibit E
       hereto.

              (vi)   The Agent's Fee Letter, executed by the Agent, the
       Borrower and the Guarantor.

       (b)    No Material Adverse Change.  No event or events which,
individually or in the aggregate has had or is reasonably likely to cause a
material adverse change in the business, assets, condition or operations of (i)
the Borrower and its Subsidiaries taken as a whole, or (ii) the Guarantor and
its Subsidiaries taken as a whole shall have occurred.





                                      -28-
<PAGE>   126
       (c)    Payment of Fees.  On the date of this Agreement, the Borrower
shall have paid the fees required by paragraphs (b) and (d) of Section 2.03 and
all costs and expenses which have been invoiced and are payable pursuant to
Section 10.04.

       (d)    No Default.  No Default shall have occurred and be continuing or
would result from such Borrowing or from the application of the proceeds
therefrom.

       (e)    Representations and Warranties.  The representations and
warranties contained in Article V hereof shall be true and correct in all
material respects on and as of the Effective Date before and after giving
effect to the initial Borrowing and to the application of the proceeds from
such Borrowing, as though made on and as of such date.

       (f)    Termination of Existing Credit Agreement.  The Agent, the Co-
Agents, the Arranger & Syndication Agent and the Banks shall have received
sufficient evidence indicating that the Borrower's and the Guarantor's
obligations under the U.S. $400,000,000 Credit Agreement dated as of March 7,
1995 among the Borrower, the Guarantor, the banks and co-agents parties
thereto,  and NationsBank of Texas, N.A., as agent, have been repaid and all
commitments of the banks party thereto have been terminated.

       (g)    No Material Litigation.  No legal or regulatory action or
proceeding has commenced and is continuing against the Borrower, the Guarantor
or any of their Subsidiaries since the date of this Agreement which could
reasonably be expected to cause a material adverse change in the business,
assets, condition or operations of (i) the Borrower and its Subsidiaries taken
as a whole, or (ii) the Guarantor and its Subsidiaries taken as a whole.

       Section 3.02.  Conditions Precedent to Each A Borrowing.  The obligation
of each Bank to make an A Advance on the occasion of any A Borrowing (including
the initial Borrowing) shall be subject to the further conditions precedent
that on the date of such A Borrowing the following statements shall be true
(and each of the giving of the applicable Notice of A Borrowing and the
acceptance by the Borrower of the proceeds of such A Borrowing shall constitute
a representation and warranty by the Borrower that on the date of such A
Borrowing such statements are true):

       (i)    the representations and warranties contained in Article V (other
              than in Section 5.05 and Section 5.06) are correct on and as of
              the date of such A Borrowing, before and after giving effect to
              such A Borrowing and to the application of the proceeds
              therefrom, as though made on and as of such date,

       (ii)   no event has occurred and is continuing, or would result from
              such A Borrowing or from the application of the proceeds
              therefrom, which constitutes an Event of Default, and

       (iii)  after giving effect to such A Borrowing and all other Borrowings
              which have been requested on or prior to such date but which have
              not been made prior to such date,





                                      -29-
<PAGE>   127
       the aggregate principal amount of all Borrowings will not exceed the
       aggregate of the Commitments;

and the Agent shall have received such other approvals, opinions or documents
as any Bank through the Agent may reasonably request.

       Section 3.03.  Conditions Precedent to Certain Borrowings.  The
obligation of each Bank to make that portion of an A Advance on the occasion of
any A Borrowing which would increase the aggregate outstanding amount of A
Advances owing to such Bank over the aggregate amount of A Advances owing to
such Bank outstanding immediately prior to the making of such Advance shall in
each case be subject to the further condition precedent that on the date of
such Borrowing, no Default occurred and is continuing, or would result from
such Borrowing or from the application of the proceeds therefrom (and each of
the giving of the applicable Notice of Borrowing and the acceptance by the
Borrower of the proceeds of such Borrowing shall constitute a representation
and warranty by the Borrower that such condition precedent is satisfied on the
date of such Borrowing).

       Section 3.04.  Conditions Precedent to Each B Borrowing.  The obligation
of each Bank which is to make a B Advance on the occasion of a B Borrowing
(including the initial B Borrowing) to make such B Advance as part of such B
Borrowing is subject to the further conditions precedent that (a) at or before
the time required by paragraph (iii) of Section 2.08(a), the Agent shall have
received the written confirmatory notice of such B Borrowing contemplated by
such paragraph, (b) on or before the date of such B Borrowing but prior to such
B Borrowing, the Agent shall have received a B Note executed by the Borrower
payable to the order of such Bank for each of the one or more B Advances to be
made by such Bank as part of such B Borrowing, in a principal amount equal to
at least the principal amount of the B Advance to be evidenced thereby and
otherwise on such terms as were agreed to for such B Advance in accordance with
Section 2.08, and (c) on the date of such B Borrowing the following statements
shall be true (and each of the giving of the applicable Notice of B Borrowing
and the acceptance by the Borrower of the proceeds of such B Borrowing shall
constitute a representation and warranty by the Borrower that on the date of
such B Borrowing such statements are true):

       (i)    the representations and warranties contained in Article V (other
              than in Section 5.05 and 5.06) are correct on and as of the date
              of such B Borrowing, before and after giving effect to such B
              Borrowing and to the application of the proceeds therefrom, as
              though made on and as of such date,

     (ii)     no event has occurred and is continuing, or would result from
              such B Borrowing or from the application of the proceeds
              therefrom, which constitutes a Default, and

    (iii)     following the making of such B Borrowing and all other Borrowings
              to be made on the same day to the Borrower under this Agreement,
              the aggregate principal amount of all Advances then outstanding
              shall not exceed the aggregate amount of the Commitments to the
              Borrower (computed without regard to any B Reduction);





                                      -30-
<PAGE>   128
and the Agent shall have received such other approvals, opinions or documents
as any Bank through the Agent may reasonably request.


                                   ARTICLE IV

                                    GUARANTY

       Section 4.01.  Guaranty.  The Guarantor hereby unconditionally
guarantees the punctual payment of the Guaranteed Obligations when due, whether
at stated maturity, by acceleration or otherwise, and agrees to pay any and all
expenses (including counsel fees and expenses) incurred by the Agent or any
Bank in enforcing any rights hereunder.  Without limiting the generality of the
foregoing, the Guarantor's liability shall extend to all amounts which
constitute part of the Guaranteed Obligations and would be owed by the Borrower
under this Agreement or any of the Notes but for the fact that the claims to
such amounts are, or are deemed to be, stayed, unenforceable, not allowable,
discharged, or otherwise reduced, restricted or limited in any manner due to
the existence of a bankruptcy, reorganization or similar proceeding involving
the Borrower.

       Section 4.02.  Guaranty Absolute.  The Guarantor guarantees that the
Guaranteed Obligations will be paid strictly in accordance with the terms of
the Credit Documents executed from time to time by the Borrower, regardless of
any law, regulation or order now or hereafter in effect in any jurisdiction
affecting any of such terms or the rights of the Agent or any Bank with respect
thereto.  The obligations of the Guarantor hereunder are independent of the
Guaranteed Obligations, and provided an Event of Default exists as to the
Borrower and is continuing at the time an action is brought, a separate action
or actions may be brought and prosecuted against the Guarantor to enforce this
Agreement, irrespective of whether any action is brought against the Borrower
or whether the Borrower is joined in any such action or actions.  The liability
of the Guarantor hereunder shall be absolute and unconditional irrespective of:

              (i)    any lack of validity or enforceability of any of the
       Credit Documents against the Borrower;

              (ii)   any change in the time, manner or place of payment of, or
       in any other term of, all or any of the Guaranteed Obligations or any
       other liabilities, or any other amendment or waiver of or any consent to
       departure from any of the Credit Documents, including, without
       limitation, any increase in the Guaranteed Obligations or any other
       liabilities resulting from the making of additional Advances guaranteed
       by the Guarantor to the Borrower or otherwise;

              (iii)  any taking, exchange, release or non-perfection of any
       collateral, or any taking, release or amendment or waiver of or consent
       to departure from any other guaranty, for all or any of the Guaranteed
       Obligations or any other liabilities;





                                      -31-
<PAGE>   129
              (iv)   any manner of application of collateral, or proceeds
       thereof, to all or any of the Guaranteed   Obligations or any other
       liabilities, or any manner of sale or other disposition of any collateral
       for all or any of the Guaranteed Obligations or any other liabilities or
       any other assets of the Borrower or any of its Subsidiaries;
        
              (v)    any change, restructuring or termination of the corporate
       structure or existence of the Borrower or any of its Subsidiaries; or

              (vi)   any other circumstances which might otherwise constitute a
       defense available to, or a discharge of, the Borrower or a guarantor.

       This guaranty shall continue to be effective or be reinstated, as the
case may be, if at any time any payment of any of the Guaranteed Obligations is
rescinded or must otherwise be returned by the Agent or any Bank upon the
insolvency, bankruptcy or reorganization of the Borrower or otherwise, all as
though such payment had not been made.

       Section 4.03.  Waiver.  The Guarantor hereby waives promptness,
diligence, notice of acceptance and any other notice with respect to any of the
Guaranteed Obligations and this Guaranty and any requirement that the Agent or
any Bank protect, secure, perfect or insure any security interest or lien or
any property subject thereto or exhaust any right to take any action against
the Borrower or any other Person or any collateral.

       Section 4.04.  Subrogation.  The Guarantor irrevocably waives any and
all rights to which it may be entitled, by operation of law or otherwise, upon
making any payment hereunder (i) to be subrogated to the rights of the Agent
and the Banks against the Borrower or any other Person with respect to such
payment or otherwise to be reimbursed, indemnified or exonerated by the
Borrower or any other Person in respect thereof or (ii) to receive any payment,
in the nature of contribution or for any other reason, from any Person who has
provided security for the Guaranteed Obligations or who has also guaranteed or
is otherwise liable for the Guaranteed Obligations with respect to which such
payment was made.  If any amount shall be paid to the Guarantor on account of
such subrogation or contribution rights at any time, such amount shall be held
in trust for the benefit of the Banks and shall forthwith be paid to the Agent
to be credited and applied upon the Guaranteed Obligations, whether matured or
unmatured, in such order as may be determined by the Agent.

       Section 4.05.  No Waiver; Remedies.  No failure on the part of the Agent
or any Bank to exercise, and no delay in exercising, any right hereunder shall
operate as a waiver thereof; nor shall any single or partial exercise of any
right hereunder preclude any other or further exercise thereof or the exercise
of any other right.  The remedies herein provided are cumulative and not
exclusive of any remedies provided by law.

       Section 4.06.  Continuing Guaranty.  This guaranty is a continuing
guaranty and shall (i) remain in full force and effect until the later of (A)
the payment in full of the Guaranteed Obligations and all other amounts payable
under this guaranty and (B) the expiration or termination





                                      -32-
<PAGE>   130
of each Commitment of each Bank to the Borrower, (ii) be binding upon the
Guarantor, its successors and assigns, (iii) inure to the benefit of, and be
enforceable by, the Agent, the Co-Agents, the Arranger & Syndication Agent, and
each of the Banks and their respective successors, transferees and assigns, and
(iv) not be terminated by the Guarantor or the Borrower.


                                   ARTICLE V

                         REPRESENTATIONS AND WARRANTIES

       Each of the Borrower and the Guarantor represents and warrants as
follows:

       Section 5.01.  Corporate Existence.  Each of the Borrower and the
Guarantor is a corporation duly organized, validly existing and in good
standing under the laws of the State of Delaware and has all corporate powers
and all governmental licenses, authorizations, certificates, consents and
approvals required to carry on its business as now conducted in all material
respects.  Each Subsidiary of the Borrower and of the Guarantor is a
corporation duly organized, validly existing and in good standing under the
laws of its jurisdiction of incorporation, except where the failure to be so
organized, existing and in good standing could not reasonably be expected to
have a material adverse effect on the business, assets, condition or operations
of (i) the Borrower and its  Subsidiaries taken as a whole, or (ii) the
Guarantor and its Subsidiaries taken as a whole.  Each such Subsidiary has all
corporate powers and all governmental licenses, authorizations, certificates,
consents and approvals required to carry on its business as now conducted in
all material respects.

       Section 5.02.  Corporate Power.  The execution, delivery and performance
by the Borrower and the Guarantor of the Credit Documents to which each is a
party and the consummation of the transactions contemplated by such Credit
Documents are within the Borrower's and the Guarantor's corporate powers,
respectively, have been duly authorized by all necessary corporate action, do
not contravene (i) the Borrower's or the Guarantor's charter or by-laws or (ii)
law or any contractual restriction binding on or affecting the Borrower or the
Guarantor and will not result in or require the creation or imposition of any
Lien prohibited by this Agreement.  At the time of each borrowing of any
Advance by the Borrower, such borrowing and the use of the proceeds of such
Advance will be within the Borrower's corporate powers, will have been duly
authorized by all necessary corporate action, will not contravene (i) the
Borrower's charter or by-laws or (ii) law or any contractual restriction
binding on or affecting the Borrower and will not result in or require the
creation or imposition of any Lien prohibited by this Agreement.

       Section 5.03.  Authorization and Approvals.  No authorization or
approval or other action by, and no notice to or filing with, any governmental
authority or regulatory body is required for the due execution, delivery and
performance by the Borrower or the Guarantor of the Credit Documents to which
each is a party or the consummation of the transactions contemplated by such
Credit Documents.  At the time of each borrowing of any Advance by the
Borrower, no authorization or





                                      -33-
<PAGE>   131
approval or other action by, and no notice to or filing with, any governmental
authority or regulatory body will be required for such borrowing or the use of
the proceeds of such Advance.

       Section 5.04.  Enforceable Obligations.  This Agreement has been duly
executed and delivered by the Borrower and the Guarantor.  This Agreement is
the legal, valid and binding obligation of the Borrower and the Guarantor
enforceable against the Borrower or the Guarantor, respectively, in accordance
with its terms, except as such enforceability may be limited by any applicable
bankruptcy, insolvency, reorganization, moratorium or similar law affecting
creditors' rights generally.  The A Notes of the Borrower are, and when
executed the B Notes of the Borrower will be, the legal, valid and binding
obligations of the Borrower enforceable against the Borrower in accordance with
their respective terms, except as such enforceability may be limited by any
applicable bankruptcy, insolvency, reorganization, moratorium or similar law
affecting creditors' rights generally.

       Section 5.05.  Financial Statements.  (a) The Consolidated and
consolidating balance sheets of the Guarantor and its Subsidiaries as at
December 31, 1995, and the related Consolidated and consolidating statements of
income and cash flows of the Guarantor and its Subsidiaries for the fiscal year
then ended, copies of which have been furnished to each Bank, and the
Consolidated and consolidating balance sheets of the Guarantor and its
Subsidiaries as at September 30, 1996, and the related Consolidated and
consolidating statements of income and cash flows of the Guarantor and its
Subsidiaries for the nine months then ended, duly certified by an authorized
financial officer of the Guarantor, copies of which have been furnished to each
Bank, fairly present (subject, in the case of such balance sheets as at
September 30, 1996, and such statements of income and cash flows for the nine
months then ended, to year-end audit adjustments) the Consolidated and
consolidating financial condition of the Guarantor and its Subsidiaries as at
such dates and the Consolidated and consolidating results of operations of the
Guarantor and its Subsidiaries for the fiscal year and nine month period,
respectively, ended on such dates, all in accordance with generally accepted
accounting principles consistently applied.  Since September 30, 1996, there
has been no material adverse change in the condition or operations of the
Guarantor or its Subsidiaries.

       (b) The consolidating balance sheets of the Guarantor and its
Subsidiaries as at December 31, 1995 and September 30, 1996 referred to in
Section 5.05(a), and the related consolidating statements of income and cash
flows of the Guarantor and its Subsidiaries for the fiscal year and nine
months, respectively, then ended referred to in Section 5.05(a), to the extent
such balance sheets and statements pertain to the Borrower, fairly present
(subject, in the case of such balance sheet as at September 30, 1996 and such
statements of income and cash flows for the nine months then ended, to year-end
audit adjustments) the Consolidated financial condition of the Borrower and its
Subsidiaries as at such dates and the Consolidated results of operations of the
Borrower and its Subsidiaries for the fiscal year and nine month period,
respectively, ended on such dates, all in accordance with generally accepted
accounting principles consistently applied.  Since September 30, 1996, there
has been no material adverse change in the condition or operations of the
Borrower or its Subsidiaries.





                                      -34-
<PAGE>   132
       Section 5.06.  Litigation.  Except as otherwise disclosed in writing by
the Borrower or the Guarantor to the Banks and the Agent after the date hereof
and approved by the Majority Banks, there is, no pending or, to the knowledge
of the Borrower or the Guarantor, threatened action or proceeding affecting the
Borrower or the Guarantor or any Subsidiary of the Borrower or the Guarantor
before any court, governmental agency or arbitrator, which could reasonably be
expected to materially and adversely affect the financial condition or
operations of the Borrower and its Subsidiaries taken as a whole, or of the
Guarantor and its Subsidiaries taken as a whole, or which purports to affect
the legality, validity, binding effect or enforceability of this Agreement or
any Note.

       Section 5.07.  Regulation U; Use of Proceeds.  Neither the Borrower nor
the Guarantor is engaged in the business of extending credit for the purpose of
purchasing or carrying margin stock (within the meaning of Regulation U issued
by the Board of Governors of the Federal Reserve System), and no proceeds of
any Advance will be used to purchase or carry any margin stock or to extend
credit to others for the purpose of purchasing or carrying any such margin
stock.  Following the application of the proceeds of each Advance, not more
than 25% of the value of the assets of the Borrower, or of the Borrower and its
Subsidiaries, which are subject to any arrangement with the Agent or any Bank
(herein or otherwise) whereby the Borrower's or any such Subsidiary's right or
ability to sell, pledge or otherwise dispose of assets is in any way restricted
will be such margin stock.

       Section 5.08.  Investment Company Act.  Neither the Borrower nor the
Guarantor is an "investment company" or a company "controlled" by an
"investment company" within the meaning of the Investment Company Act of 1940,
as amended.

       Section 5.09.  ERISA.  No Termination Event has occurred or is
reasonably expected to occur with respect to any Plan for which an
Insufficiency exists.  Neither the Guarantor nor any ERISA Affiliate of the
Guarantor has received any notification that any Multiemployer Plan is in
reorganization or has been terminated, within the meaning of Title IV of ERISA,
and the Guarantor is not aware of any reason to expect that any Multiemployer
Plan is to be in reorganization or to be terminated within the meaning of Title
IV of ERISA.

       Section 5.10.  Taxes.  As of the date of this Agreement, the United
States federal income tax returns of the Borrower and the Guarantor, and the
Subsidiaries of the Borrower and the Guarantor, have been examined through the
fiscal year ended December 31, 1989.  The Borrower and the Subsidiaries of the
Borrower have filed all United States Federal income tax returns and all other
material domestic tax returns which are required to be filed by them and have
paid, or provided for the payment before the same become delinquent of, all
taxes due pursuant to such returns or pursuant to any assessment received by
the Borrower or any such Subsidiary, other than those taxes contested in good
faith by appropriate proceedings.  The charges, accruals and reserves on the
books of the Borrower and the Subsidiaries of the Borrower in respect of taxes
are adequate.





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       Section 5.11.  Holding Company.  Neither the Borrower nor the Guarantor
is a "holding company", or a "subsidiary company" of a "holding company", or an
"affiliate" of a "holding company" or of a "subsidiary company" of a "holding
company", or a "public utility" within the meaning of the Public Utility
Holding Company Act of 1935, as amended.

       Section 5.12.  Environmental Condition.  Except as set forth in any
reports filed with the Securities and Exchange Commission (copies of which have
been received by the Banks) pertaining to certain Environmental matters, the
Borrower and the Guarantor and their respective Subsidiaries are in compliance
in all material respects with all Environmental Protection Statutes to the
extent material to their respective operations or financial condition.  As of
the date of this Agreement, there are no material Environmental matters
outstanding.  The aggregate contingent and non-contingent liabilities of the
Borrower, the Guarantor and their respective Subsidiaries which are reasonably
expected to arise in connection with (i) the requirements of Environmental
Protection Statutes or (ii) any obligation or liability to any Person in
connection with any Environmental matters (including, without limitation, any
release or threatened release (as such terms are defined in the Comprehensive
Environmental Response, Compensation and Liability Act of 1980) of any
Hazardous Waste, Hazardous Substance, other waste, petroleum or petroleum
products into the Environment) does not exceed 10% of the Consolidated Tangible
Net Worth of the Guarantor (excluding liabilities to the extent covered by
insurance if the insurer has confirmed that such insurance covers such
liabilities).

       Section 5.13.  Ownership of Borrower.  The Guarantor owns 100% of the
outstanding shares of capital stock of the Borrower, and will derive
substantial direct and indirect benefit from the transactions contemplated by
this Agreement.

       Section 5.14.  Guarantor's Independent Decision.  The Guarantor has,
independently and without reliance upon the Agent or any Bank, and based on
documents and information as it has deemed appropriate, made its own credit
analysis and decision to enter into this Agreement and to undertake the
guaranty set forth in Article IV hereof.


                                   ARTICLE VI

                             AFFIRMATIVE COVENANTS

       So long as any Note shall remain unpaid or any Bank shall have any
Commitment hereunder, unless the Majority Banks shall otherwise consent in
writing:

       Section 6.01.  Compliance with Laws, Etc.  Each of the Borrower and the
Guarantor will comply, and cause each of its Subsidiaries to comply, in all
material respects with all applicable laws, rules, regulations and orders, such
compliance to include, without limitation, the payment and discharge before the
same become delinquent of all taxes, assessments and governmental charges or
levies imposed upon it or any of its Subsidiaries or upon any of its property
or any property of any of its Subsidiaries, and all lawful claims which, if
unpaid, might become a Lien upon any property





                                      -36-
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of it or any of its Subsidiaries, provided that neither the Borrower nor the
Guarantor nor any Subsidiary of the Borrower or the Guarantor shall be required
to pay any such tax, assessment, charge, levy or claim which is being contested
in good faith and by proper proceedings and with respect to which reserves in
conformity with generally accepted accounting principles, if required by such
principles, have been provided on the books of the Borrower or the Guarantor or
such Subsidiary, as the case may be.

       Section 6.02.  Reporting Requirements.  The Guarantor will furnish to
each of the Banks:
       (a)    as soon as possible and in any event within five days
after the occurrence of each Default continuing on the date of such statement,
a statement of an authorized financial officer of the Borrower or the
Guarantor, as the case may be, setting forth the details of such Default and
the actions, if any, which the Borrower or the Guarantor has taken and proposes
to take with respect thereto;

       (b)    as soon as available and in any event not later than 60 days
after the end of each of the first three quarters of each fiscal year of the
Guarantor, the Consolidated and consolidating balance sheets of the Guarantor
and its Subsidiaries as of the end of such quarter (such consolidating balance
sheets to reflect such Subsidiaries, including the Borrower, as separate
entities) and the Consolidated and consolidating statements of income and cash
flow statements of the Guarantor and its Subsidiaries for the period commencing
at the end of the previous year and ending with the end of such quarter (such
consolidating statements of income and cash flow statements to reflect such
Subsidiaries, including the Borrower, as separate entities), all in reasonable
detail and duly certified (subject to year-end audit adjustments) by an
authorized financial officer of the Guarantor as having been prepared in
accordance with generally accepted accounting principles, together with a
certificate of said officer (i) stating that he has no knowledge that a Default
has occurred, or, if a Default has occurred and is continuing, a statement as
to the nature thereof and the action, if any, which the Guarantor proposes to
take with respect thereto, and (ii) showing in detail the calculation
supporting such statement in respect of Section 7.01;

       (c)    as soon as available and in any event not later than 120 days
after the end of each fiscal year of the Guarantor, a copy of the annual audit
report for such year for the Guarantor and its Subsidiaries, including therein
Consolidated and consolidating balance sheets of the Guarantor and its
Subsidiaries as of the end of such fiscal year (such consolidating balance
sheets to reflect such Subsidiaries, including the Borrower, as separate
entities) and Consolidated and consolidating statements of income and cash flow
statements of the Guarantor and its Subsidiaries for such fiscal year (such
consolidating statements of income and cash flow statements to reflect such
Subsidiaries, including the Borrower, as separate entities), in each case
prepared in accordance with generally accepted accounting principles and
certified by KPMG Peat Marwick or other independent certified public
accountants of recognized standing acceptable to the Majority Banks, together
with a certificate of such accounting firm to the Banks (i) stating that, in
the course of the regular audit of the business of the Guarantor and its
Subsidiaries, which audit was conducted by such accounting firm in accordance
with generally accepted auditing standards, such accounting firm has obtained





                                      -37-
<PAGE>   135
no knowledge that a Default has occurred and is continuing, or if, in the
opinion of such accounting firm, a Default has occurred and is continuing, a
statement as to the nature thereof, and (ii) showing in detail the calculations
supporting such statement in respect of Section 7.01;

       (d)    promptly after the end of each fiscal quarter, copies of all
proxy material, reports and other information which the Guarantor sends to any
of its security holders, and copies of all reports and registration statements
which the Guarantor or any Subsidiary of the Guarantor files with the
Securities and Exchange Commission or any national securities exchange;

       (e)    as soon as possible and in any event (i) within 30 Business Days
after the Guarantor or any ERISA Affiliate of the Guarantor knows or has reason
to know that any Termination Event described in clause (i) of the definition of
Termination Event with respect to any Plan has occurred and (ii) within 10
Business Days after the Guarantor or any ERISA Affiliate of the Guarantor knows
or has reason to know that any other Termination Event with respect to any Plan
has occurred or is reasonably expected to occur, a statement of the chief
financial officer or chief accounting officer of the Guarantor describing such
Termination Event and the action, if any, which the Guarantor or such ERISA
Affiliate of the Guarantor proposes to take with respect thereto;

       (f)    promptly after receipt thereof by the Guarantor or any ERISA
Affiliate of the Guarantor, copies of each notice received by the Guarantor or
any ERISA Affiliate of the Guarantor from the PBGC stating its intention to
terminate any Plan or to have a trustee appointed to administer any Plan;

       (g)    within 30 days following request therefor by any Bank, copies of
each Schedule B (Actuarial Information) to each annual report (Form 5500
Series) of the Guarantor or any ERISA Affiliate of the Guarantor with respect
to each Plan;

       (h)    promptly after receipt thereof by the Guarantor or any ERISA
Affiliate of the Guarantor from the sponsor of a Multiemployer Plan, a copy of
each notice received by the Guarantor or any ERISA Affiliate of the Guarantor
concerning (i) the imposition of a Withdrawal Liability by a Multiemployer
Plan, (ii) the determination that a Multiemployer Plan is, or is expected to
be, in reorganization within the meaning of Title IV of ERISA, (iii) the
termination of a Multiemployer Plan within the meaning of Title IV of ERISA, or
(iv) the amount of liability incurred, or expected to be incurred, by the
Guarantor or any ERISA Affiliate of the Guarantor in connection with any event
described in clause (i), (ii) or (iii) above;

       (i)    promptly after it has knowledge of (A) any material litigation
pending or threatened against it which could reasonably be expected to cause a
material adverse change in the financial condition of the Borrower, the
Guarantor, or any Subsidiary, or (B) the occurrence of any other contingency
which could reasonably be expected to cause a material adverse change in the
financial condition of the Borrower, the Guarantor or any Subsidiary; and





                                      -38-
<PAGE>   136
       (j)    such other information respecting the business or properties, or
the condition or operations, financial or otherwise, of the Borrower or the
Guarantor or any of their Subsidiaries as any Bank through the Agent may from
time to time reasonably request.

       Section 6.03.  Use of Proceeds.  The Borrower will use the proceeds of
the Advances only for general corporate purposes, including without limitation
to repay maturing commercial paper of the Borrower.

       Section 6.04.  Maintenance of Insurance.  Each of the Borrower and the
Guarantor will maintain, and cause each of its Subsidiaries to maintain,
insurance with responsible and reputable insurance companies or associations in
such amounts and covering such risks as is usually carried by companies engaged
in similar businesses and owning similar properties in the same general areas
in which the Borrower or the Guarantor or its respective Subsidiaries operate,
provided that the Borrower or the Guarantor or any of its respective
Subsidiaries may self-insure to the extent and in the manner normal for
companies of like size, type and financial condition.

       Section 6.05.  Preservation of Corporate Existence, Etc.  Each of the
Borrower and the Guarantor will preserve and maintain, and cause each of its
Subsidiaries to preserve and maintain, its corporate existence, rights,
franchises and privileges in the jurisdiction of its incorporation, and qualify
and remain qualified, and cause each Subsidiary to qualify and remain
qualified, as a foreign corporation in each jurisdiction in which qualification
is necessary or desirable in view of its business and operations or the
ownership of its properties, except in the case of any Subsidiary where the
failure of such Subsidiary to so preserve, maintain, qualify and remain
qualified could not reasonably be expected to have a material adverse effect on
the business, assets, condition or operations of the Borrower and its
Subsidiaries taken as a whole, or of the Guarantor and its Subsidiaries taken
as a whole; provided, however, that nothing herein contained shall prevent any
transaction permitted by Section 7.03.

       Section 6.06.  Payment of Taxes, Etc.  Each of the Borrower and the
Guarantor will pay and discharge, and cause each of its Subsidiaries to pay and
discharge, before the same shall become delinquent and which the failure to
timely pay or discharge could reasonably be expected to have a material adverse
effect on the business, assets, condition or operations of the Borrower and its
Subsidiaries taken as a whole, or of the Guarantor and its Subsidiaries taken
as a whole, (a) all taxes, assessments and governmental charges or levies
imposed upon it or upon its income or profits of property that are material in
amount, prior to the date on which penalties attach thereto and (b) all lawful
claims that are material in amount which, if unpaid, might by law become a Lien
upon its property; provided, however, that neither the Borrower, the Guarantor,
nor any such Subsidiary shall be required to pay or discharge any such tax,
assessment, charge, levy, or claim which is being contested in good faith and
by appropriate proceedings, and with respect to which reserves in conformity
with generally accepted accounting principles have been provided.

       Section 6.07.  Visitation Rights.  At any reasonable time and from time
to time and so long as any visit or inspection will not unreasonably interfere
with the operations of the Borrower, the





                                      -39-
<PAGE>   137
Guarantor or any of their Subsidiaries, upon reasonable notice, each of the
Borrower and the Guarantor will, and will cause its Subsidiaries to, permit the
Agent and any Bank or any of its agents or representatives thereof, to examine
and make copies of and abstracts from the records and books of account of, and
visit and inspect at its reasonable discretion the properties of, the Borrower,
the Guarantor and any such Subsidiary, to discuss the affairs, finances and
accounts of the Borrower, the Guarantor and any such Subsidiary with any of
their respective officers or directors.


                                  ARTICLE VII

                               NEGATIVE COVENANTS

       So long as any Note shall remain unpaid or any Bank shall have any
Commitment to the Borrower hereunder, without the written consent of the
Majority Banks:

       Section 7.01.  Financial Covenants.  The Guarantor will not:  (a)
declare or make any Restricted Payments unless (i) no Default or Event of
Default shall have occurred and be continuing, and (ii) the amount of all such
Restricted Payments made on or after January 1, 1997 shall not exceed an amount
equal to (x) $275,000,000, plus (y) 75% of the Guarantor's Consolidated net
income for the period on or after January 1, 1997 to the date on which such
Restricted Payment is to be made (minus 100% of cumulative losses), plus (z)
100% of the net cash proceeds of any capital stock offering of the Guarantor
effective on or after January 1, 1997; or

       (b) as of the last day of each calendar quarter, permit the Consolidated
Debt of the Guarantor to exceed 50% of the Consolidated Capitalization of the
Guarantor.

       Section 7.02.  Liens, Etc.  Neither the Borrower nor the Guarantor will
create, assume, incur or suffer to exist, or permit any of the Restricted
Subsidiaries to create, assume, incur or suffer to exist, any Lien on or in
respect of any of its property, whether now owned or hereafter acquired, or
assign or otherwise convey, or permit any such Restricted Subsidiary to assign
or otherwise convey, any right to receive income, in each case to secure or
provide for the payment of any Debt of any Person, except Permitted Liens.

       Section 7.03.  Merger and Sale of Assets.  Neither the Borrower nor the
Guarantor will merge or consolidate with or into any other Person, or sell,
lease or otherwise transfer a Substantial Part of the assets of the Guarantor
and the Restricted Subsidiaries, or permit any of the Restricted Subsidiaries
to merge or consolidate with or into any other Person, or sell, lease or
otherwise transfer a Substantial Part of the assets of the Guarantor and the
Restricted Subsidiaries, except that this Section 7.03 shall not prohibit:

              (i) a sale of any account receivable without recourse or any
       discount of an account receivable provided that (A) in the case of such
       a sale, the sale proceeds are not less than the greater of either the
       face value or the fair market value of such receivable and (B) in the
       case





                                      -40-
<PAGE>   138
       of such a discount, the discount does not exceed the greater of 20% of
       either the face value or the fair market value of such receivable;

              (ii) the Guarantor and the Restricted Subsidiaries from selling
       any assets if 100% of the net proceeds of such sale are (1) reinvested
       in the Guarantor's or the Borrower's business; (2) used to repay
       outstanding Debt of the Guarantor or the Borrower; or (3) used to make
       Restricted Payments permitted by Section 7.01(a); and

              (iii) any of the Guarantor or a Restricted Subsidiary from
       merging or consolidating with or into any Person, or transferring a
       Substantial Part of the assets of the Guarantor and the Restricted
       Subsidiaries to such Person, if in each case (x) such Person is a
       corporation organized under the laws of the United States or any state
       thereof, (y) such Person expressly assumes in writing all obligations of
       the Borrower and the Guarantor hereunder, and (z) no Default or Event of
       Default has occurred and is continuing.

       Section 7.04.  Agreements to Restrict Dividends and Certain Transfers.
Neither the Borrower nor the Guarantor will enter into or suffer to exist, or
permit any of its Subsidiaries to enter into or suffer to exist, any consensual
encumbrance or restriction on the ability of any Subsidiary of the Guarantor
(i) to pay, directly or indirectly, dividends or make any other distributions
in respect of its capital stock or pay any Debt or other obligation owed to the
Guarantor or to any Subsidiary of the Guarantor; or (ii) to make loans or
advances to the Guarantor or any Subsidiary of the Guarantor, except those
encumbrances and restrictions existing on the date hereof and described in
Schedule IV and those now or hereafter existing that are not more restrictive
in any respect than such encumbrances and restrictions described in Schedule
IV.

       Section 7.05.  Compliance with ERISA.  The Guarantor will not (i)
terminate, or permit any ERISA Affiliate of the Guarantor to terminate, any
Plan so as to result in any liability of the Guarantor or any such ERISA
Affiliate to the PBGC in excess of $5,000,000, or (ii) permit to exist any
occurrence of any Termination Event with respect to a Plan for which there is
an Insufficiency in excess of $5,000,000.

       Section 7.06.  Transactions with Affiliates.  Neither the Borrower nor
the Guarantor will make any material sale to, make any material purchase from,
extend material credit to, make material payment for services rendered by, or
enter into any other material transaction with, or permit any Restricted
Subsidiary to make any material sale to, make any material purchase from,
extend material credit to, make material payment for services rendered by, or
enter into any other material transaction with, any Affiliate of the Borrower
or the Guarantor or of such Restricted Subsidiary unless as a whole such sales,
purchases, extensions of credit, rendition of services and other transactions
are (at the time such sale, purchase, extension of credit, rendition of
services or other transaction is entered into) (i) in the ordinary course of
business, (ii) upon terms no less favorable to the Borrower or the Guarantor or
such Restricted Subsidiary than it would obtain in a comparable





                                      -41-
<PAGE>   139
arms-length transaction with a Person not an Affiliate, and (iii) on terms and
conditions reasonably fair in all material respects to the Borrower or the
Guarantor or such Restricted Subsidiary in the good faith judgment of the
Borrower or the Guarantor, as the case may be.

       Section 7.07.  Change of Business.  Neither the Borrower nor the
Guarantor will, or will permit any Restricted Subsidiary to, materially change
the general nature of its business.

       Section 7.08.  Limitation on Loans, Advances and Investments.  Neither
the Borrower nor the Guarantor will, or will permit any Restricted Subsidiary
to, make or permit to exist any loans, advances or capital contributions to, or
make any investment in, or purchase or commit to purchase any stock or other
securities or evidences of indebtedness of or interests in any Person, except
the following:

       (a)    as shown on the attached Schedule V;

       (b)    the purchase of Liquid Investments;

       (c)    trade and customer accounts receivable which are for goods
furnished or services rendered in the ordinary course of business and are
payable in accordance with customary trade terms;

       (d)    ordinary course of business contributions, loans or advances to,
or investments in, a Restricted Subsidiary; and

       (e)    other capital investments not otherwise permitted by this Section
7.08 in any Person not a Restricted Subsidiary provided that (i) the aggregate
amount of such investments for the Borrower, the Guarantor, and all Restricted
Subsidiaries which are outstanding at any time shall not exceed $25,000,000;
(ii) such Person shall be in the same or substantially similar line or lines of
business as the Guarantor and the Restricted Subsidiaries; and (iii) the
liabilities of such other Person shall be nonrecourse to the Guarantor and the
Restricted Subsidiaries.

       Section 7.09.  Fiscal Year; Accounting Practices.  Neither the Borrower
nor the Guarantor will change, or will permit any Restricted Subsidiary to
change (a) its fiscal year from that existing as of the date of this Agreement,
or (b) its accounting principles and practices (except as may be required by
reason of a change in generally accepted accounting principles) from those
reflected in the financial statements referred to in Section 5.05 in any manner
which would materially affect any accounting determination contemplated by this
Agreement.





                                      -42-
<PAGE>   140
                                  ARTICLE VIII

                               EVENTS OF DEFAULT

       Section 8.01.  Events of Default.  If any of the following events
("Events of Default") shall occur and be continuing:
       
       (a)    the Borrower shall fail to pay any principal of any
Advance when the same becomes due and payable in accordance with the terms
hereof, or shall fail to pay any interest on any such Advance or any fee or
other amount to be paid by it hereunder within five days after the same becomes
due and payable in accordance with the terms hereof; or

       (b)    any certification, representation or warranty made by the
Borrower or the Guarantor herein or by the Borrower or the Guarantor (or any of
their respective officers) in writing (including representations and warranties
deemed made pursuant to Section 3.02, 3.03 or 3.04) under or in connection with
any Credit Document shall prove to have been incorrect in any material respect
when made or deemed made; or

       (c)    the Borrower or the Guarantor shall fail to perform or observe
(i) any term, covenant or agreement contained in Section 6.02 on its part to be
performed or observed and such failure shall continue for three Business Days
after the earlier of the date notice thereof shall have been given to the
Borrower or the Guarantor by the Agent or any Bank or the date the Borrower or
the Guarantor shall have knowledge of such failure, or (ii) any covenant
contained in Section 6.05 (other than with respect to maintaining the corporate
existence of the Borrower or the Guarantor or maintaining any franchise of the
Borrower or the Guarantor which is material to the Borrower's or the
Guarantor's business and operations) and such failure shall continue for 30
days after the earlier of the date notice thereof shall have been given to the
Borrower or the Guarantor by the Agent or any Bank or the date the Borrower or
the Guarantor shall have knowledge of such failure, or (iii) any term (other
than a representation and warranty), covenant or agreement contained in any
Credit Document (other than a term, covenant or agreement the noncompliance
with which would be governed by clauses (i) and (ii) of this paragraph (c)) on
its part to be performed or observed; or

       (d)    the Borrower, the Guarantor, or any Restricted Subsidiary shall
fail to pay any principal of or premium or interest on any of its Debt which is
outstanding in a principal amount of at least $25,000,000 in the aggregate
(excluding Debt evidenced by the Notes) when the same becomes due and payable
(whether by scheduled maturity, required prepayment, acceleration, demand or
otherwise), and such failure shall continue after the applicable grace period,
if any, specified in the agreement or instrument relating to such Debt; or any
other event shall occur or condition shall exist under any agreement or
instrument relating to any such Debt and shall continue after the applicable
grace period, if any, specified in such agreement or instrument, if the effect
of such event or condition is to accelerate, or to permit the acceleration of,
the maturity of such Debt;





                                      -43-
<PAGE>   141
or any such Debt shall be declared to be due and payable, or required to be
prepaid (other than by a regularly scheduled required prepayment), prior to the
stated maturity thereof; or

       (e)    the Borrower, the Guarantor, or any Restricted Subsidiary shall
generally not pay its debts as such debts become due, or shall admit in writing
its inability to pay its debts generally, or shall make a general assignment
for the benefit of creditors; or any proceeding shall be instituted by or
against the Borrower, the Guarantor, or any Restricted Subsidiary seeking to
adjudicate it a bankrupt or insolvent, or seeking liquidation, winding up,
reorganization, arrangement, adjustment, protection, relief, or composition of
it or its debts under any law relating to bankruptcy, insolvency or
reorganization or relief of debtors, or seeking the entry of an order for
relief or the appointment of a receiver, trustee, or other similar official for
it or for any substantial part of its property and, in the case of any such
proceeding instituted against it (but not instituted by it), shall remain
undismissed or unstayed for a period of 30 days; or the Borrower, the
Guarantor, or any Restricted Subsidiary shall take any corporate action to
authorize any of the actions set forth above in this subsection (e); or

       (f)    any judgments or orders for the payment of money in excess of
$10,000,000 individually or $25,000,000 in the aggregate shall be rendered
against the Borrower, the Guarantor, or any Restricted Subsidiary and remain
unsatisfied and either (i) enforcement proceedings shall have been commenced by
any creditor upon such judgments or orders or (ii) there shall be any period of
30 consecutive days during which a stay of enforcement of such judgments or
orders, by reason of a pending appeal or otherwise, shall not be in effect; or

       (g)    any Termination Event with respect to a Plan shall have occurred
and, 30 days after notice thereof shall have been given to the Borrower and the
Guarantor by the Agent, (i) such Termination Event shall still exist and (ii)
the sum (determined as of the date of occurrence of such Termination Event) of
the Insufficiency of such Plan and the Insufficiency of any and all other Plans
with respect to which a Termination Event shall have occurred and then exist
(or in the case of a Plan with respect to which a Termination Event described
in clause (ii) of the definition of Termination Event shall have occurred and
then exist, the liability related thereto) is equal to or greater than
$10,000,000; or

       (h)    the Guarantor or any ERISA Affiliate of the Guarantor shall have
been notified by the sponsor of a Multiemployer Plan that it has incurred
Withdrawal Liability to such Multiemployer Plan in an amount which, when
aggregated with all other amounts required to be paid to Multiemployer Plans in
connection with Withdrawal Liabilities (determined as of the date of such
notification), exceeds $10,000,000 in the aggregate or requires payments
exceeding $5,000,000 per annum; or

       (i)    the Guarantor or any ERISA Affiliate of the Guarantor shall have
been notified by the sponsor of a Multiemployer Plan that such Multiemployer
Plan is in reorganization or is being





                                     -44-
<PAGE>   142
terminated, within the meaning of Title IV of ERISA, if as a result of such
reorganization or termination the aggregate annual contributions of the
Guarantor and its ERISA Affiliates to all Multiemployer Plans which are then in
reorganization or being terminated have been or will be increased over the
amounts contributed to such Multiemployer Plans for the respective plan years
which include the date hereof by an amount exceeding $10,000,000; or

       (j)    the Guarantor shall cease to own directly or indirectly 100% of
the capital stock of the Borrower; or

       (k)    any Person or group (or any Affiliate of such Person or group) --
other than Petrofina S.A., a societe anonyme (corporation) organized and
existing under the laws of the Kingdom of Belgium ("Petrofina"), or Petrofina
Delaware, Incorporated, a Delaware corporation ("PDI"), or any wholly-owned
Subsidiary of Petrofina or PDI --  shall beneficially own, directly or
indirectly, capital stock of the Guarantor representing 30% or more of the
voting power of all capital stock of the Guarantor; or

       (l)    any "Event of Default" (as such term is defined in the Parallel
Agreement) shall occur and be continuing.

then, and in any such event, the Agent (i) shall at the request, or may with
the consent, of the Majority Banks, by notice to the Borrower, declare all of
the Commitments and the obligation of each Bank to make Advances to be
terminated, whereupon all of the Commitments and each such obligation shall
forthwith terminate, and (ii) shall at the request, or may with the consent of
the Majority Banks, by notice to the Borrower declare the Notes, all interest
thereon and all other amounts payable by the Borrower and the Guarantor under
this Agreement to be forthwith due and payable, whereupon such Notes, such
interest and all such amounts shall become and be forthwith due and payable,
without requirement of any presentment, demand, protest, notice of intent to
accelerate, further notice of acceleration or other further notice of any kind
(other than the notice expressly provided for above), all of which are hereby
expressly waived by the Borrower and the Guarantor; provided, however, that in
the event of any Event of Default described in Section 8.01(e) with respect to
the Borrower or the Guarantor, (A) the obligation of each Bank to make Advances
shall automatically be terminated and (B) the Notes, all such interest and all
such amounts shall automatically become and be due and payable, without
presentment, demand, protest, notice of intent to accelerate, notice of
acceleration or any other notice of any kind, all of which are hereby expressly
waived by the Borrower and the Guarantor.





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<PAGE>   143
                                   ARTICLE IX

         THE AGENT, THE CO-AGENTS, AND THE ARRANGER & SYNDICATION AGENT

       Section 9.01.  Authorization and Action.  Each Bank hereby appoints and
authorizes the Agent to take such action as agent on its behalf and to exercise
such powers under the Credit Documents as are delegated to the Agent by the
terms hereof and thereof, together with such powers as are reasonably
incidental thereto.  As to any matters not expressly provided for by the Credit
Documents (including, without limitation, enforcement or collection of the
Notes), the Agent shall not be required to exercise any discretion or take any
action, but shall be required to act or to refrain from acting (and shall be
fully protected in so acting or refraining from acting) upon the instructions
of the Majority Banks, and such instructions shall be binding upon all Banks
and all holders of Notes; provided, however, that the Agent shall not be
required to take any action which exposes the Agent to personal liability or
which is contrary to any Credit Document or applicable law.  The Agent agrees
to give to each Bank prompt notice of each notice given to it by the Borrower
pursuant to the terms of this Agreement.

       Section 9.02.  Agent's Reliance, Etc.  Neither the Agent nor any of its
directors, officers, agents or employees shall be liable for any action taken
or omitted to be taken by it or them under or in connection with the Credit
Documents, except for its or their own gross negligence or willful misconduct.
Without limitation of the generality of the foregoing, the Agent:  (i) may
treat the payee of any Note as the holder thereof until the Agent receives and
accepts an Assignment executed by the Borrower, the Bank which is the payee of
such Note, as assignor, and the assignee in accordance with Section 10.06; (ii)
may consult with legal counsel (including counsel for the Borrower),
independent public accountants and other experts selected by it and shall not
be liable for any action taken or omitted to be taken in good faith by it in
accordance with the advice of such counsel, accountants or experts; (iii) makes
no warranty or representation to any Bank and shall not be responsible to any
Bank for any statements, warranties or representations made in or in connection
with the Credit Documents; (iv) shall not have any duty to ascertain or to
inquire as to the performance or observance of any of the terms, covenants or
conditions of the Credit Documents on the part of the Borrower or the Guarantor
or to inspect the property (including the books and records) of the Borrower or
the Guarantor; (v) shall not be responsible to any Bank for the due execution,
legality, validity, enforceability, genuineness, sufficiency or value of the
Credit Documents; and (vi) shall incur no liability under or in respect of the
Credit Documents by acting upon any notice, consent, certificate or other
instrument or writing (which may be by telecopier, telegram, cable or telex)
believed by it to be genuine and signed or sent by the proper party or parties.

       Section 9.03.  NationsBank and Affiliates.  With respect to its
Commitment, the Advances made by it and the Notes issued to it, NationsBank
shall have the same rights and powers under the Credit Documents and any Note
payable to NationsBank as any other Bank and may exercise the same as though it
was not the Agent; and the term "Bank" or "Banks" shall, unless otherwise





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<PAGE>   144
expressly indicated, include NationsBank in its individual capacity.
NationsBank and its affiliates may accept deposits from, lend money to, act as
trustee under indentures of, and generally engage in any kind of business with,
the Borrower, the Guarantor, any Subsidiary of the Borrower or the Guarantor
and any Person who may do business with or own securities of the Borrower, the
Guarantor, or any such Subsidiary, all as if NationsBank were not the Agent and
without any duty to account therefor to the Banks.

       Section 9.04.  Bank Credit Decision.  Each Bank acknowledges that it
has, independently and without reliance upon the Agent, the Arranger &
Syndication Agent or any other Bank and based on the financial statements
referred to in Section 5.05 and such other documents and information as it has
deemed appropriate, made its own credit analysis and decision to enter into
this Agreement.  Each Bank also acknowledges that it will, independently and
without reliance upon the Agent, the Arranger & Syndication Agent or any other
Bank and based on such documents and information as it shall deem appropriate
at the time, continue to make its own credit decisions in taking or not taking
action under the Credit Documents.

       SECTION 9.05.  INDEMNIFICATION.  THE BANKS AGREE TO INDEMNIFY THE AGENT,
EACH CO-AGENT, AND THE ARRANGER & SYNDICATION AGENT (TO THE EXTENT NOT
REIMBURSED BY THE BORROWER OR THE GUARANTOR), RATABLY ACCORDING TO THE
RESPECTIVE PRINCIPAL AMOUNTS OF THE A NOTES THEN HELD BY EACH OF THEM (OR IF NO
A NOTES ARE AT THE TIME OUTSTANDING OR IF ANY A NOTES ARE HELD BY PERSONS WHICH
ARE NOT BANKS, RATABLY ACCORDING TO EITHER (I) THE RESPECTIVE AMOUNTS OF THEIR
COMMITMENTS, OR (II) IF ALL COMMITMENTS HAVE TERMINATED, THE RESPECTIVE AMOUNTS
OF THE COMMITMENTS IMMEDIATELY PRIOR TO THE TIME THE COMMITMENTS TERMINATED),
FROM AND AGAINST ANY AND ALL LIABILITIES, OBLIGATIONS, LOSSES, DAMAGES,
PENALTIES, ACTIONS, JUDGMENTS, SUITS, COSTS, EXPENSES OR DISBURSEMENTS OF ANY
KIND OR NATURE WHATSOEVER WHICH MAY BE IMPOSED ON, INCURRED BY, OR ASSERTED
AGAINST THE AGENT, SUCH CO-AGENT OR THE ARRANGER & SYNDICATION AGENT IN ANY WAY
RELATING TO OR ARISING OUT OF THE CREDIT DOCUMENTS OR ANY ACTION TAKEN OR
OMITTED BY THE AGENT UNDER THE CREDIT DOCUMENTS, PROVIDED THAT NO BANK SHALL BE
LIABLE TO THE AGENT, ANY CO-AGENT OR THE ARRANGER & SYNDICATION AGENT FOR ANY
PORTION OF SUCH LIABILITIES, OBLIGATIONS, LOSSES, DAMAGES, PENALTIES, ACTIONS,
JUDGMENTS, SUITS, COSTS, EXPENSES OR DISBURSEMENTS RESULTING FROM THE AGENT'S,
SUCH CO-AGENT'S OR THE ARRANGER & SYNDICATION AGENT'S GROSS NEGLIGENCE OR
WILLFUL MISCONDUCT.  WITHOUT LIMITATION OF THE FOREGOING, EACH BANK AGREES TO
REIMBURSE THE AGENT PROMPTLY UPON DEMAND FOR ITS RATABLE SHARE OF ANY
OUT-OF-POCKET EXPENSES (INCLUDING COUNSEL





                                      -47-
<PAGE>   145
FEES) INCURRED BY THE AGENT IN CONNECTION WITH THE PREPARATION, EXECUTION,
DELIVERY, ADMINISTRATION, MODIFICATION, AMENDMENT OR ENFORCEMENT (WHETHER
THROUGH NEGOTIATIONS, LEGAL PROCEEDINGS OR OTHERWISE) OF, OR LEGAL ADVICE IN
RESPECT OF RIGHTS OR RESPONSIBILITIES UNDER, THE CREDIT DOCUMENTS TO THE EXTENT
THAT THE AGENT IS NOT REIMBURSED FOR SUCH EXPENSES BY THE BORROWER OR THE
GUARANTOR.

       Section 9.06.  Successor Agent.  The Agent may resign at any time as
Agent under this Agreement by giving written notice thereof to the Banks and
the Borrower and may be removed at any time by the Borrower if at any time the
Agent, in its individual capacity as a Bank hereunder, shall hold less than
$30,000,000 of the aggregate Commitments.  Upon any such resignation or
removal, the Borrower shall have the right to appoint, with the consent of the
Majority Banks (which consent shall not be unreasonably withheld), a successor
Agent.  If no successor Agent shall have been so appointed by the Borrower with
such consent of the Majority Banks, and shall have accepted such appointment,
within 30 days after the retiring Agent's giving of notice of resignation or
the Borrower's removal of the retiring Agent, then the retiring Agent may, on
behalf of the Banks, appoint a successor Agent, which shall be a Bank which is
a commercial bank organized under the laws of the United States of America or
of any State thereof and having a combined capital and surplus of at least
$500,000,000.  Upon the acceptance of any appointment as Agent under this
Agreement by a successor Agent, such successor Agent shall thereupon succeed to
and become vested with all the rights, powers, privileges and duties of the
retiring Agent and shall function as the Agent under this Agreement, and the
retiring Agent shall be discharged from its duties and obligations as Agent
under this Agreement.  After any retiring Agent's resignation or removal
hereunder as Agent, the provisions of this Article IX shall inure to its
benefit as to any actions taken or omitted to be taken by it while it was Agent
under this Agreement.

       Section 9.07.  Co-Agents; Arranger & Syndication Agent.  The Co-Agents
and the Arranger & Syndication Agent shall have no duties, obligations, or
liabilities in their capacities as such.


                                   ARTICLE X

                                 MISCELLANEOUS

       Section 10.01.  Amendments, Etc.  No amendment or waiver of any
provision of any Credit Document, nor consent to any departure by the Borrower
or the Guarantor therefrom, shall in any event be effective unless the same
shall be in writing and signed by the Borrower and the Majority Banks, and then
such waiver or consent shall be effective only in the specific instance and for
the specific purpose for which given; provided, however, that no amendment,
waiver or consent shall, unless in writing and signed by all the Banks, do any
of the following:  (a) waive any of the





                                      -48-
<PAGE>   146
conditions specified in Article III, (b) increase the aggregate amount of the
Commitments to greater than the Aggregate Commitment Limit or subject the Banks
to any additional obligations, (c) reduce the principal of, or interest on, the
Notes or any fees or other amounts payable hereunder, (d) postpone any date
fixed for any payment of principal of, or interest on, the Notes or any fees or
other amounts payable hereunder, (e) take action which requires the signing of
all the Banks pursuant to the terms of this Agreement, (f) change the
percentage of the Commitments or of the aggregate unpaid principal amount of
the Notes, or the number of Banks, which shall be required for the Banks or any
of them to take any action under this Agreement or any other Credit Document,
(g) release the Guarantor or otherwise change any obligation of the Guarantor
to pay any amount payable by the Guarantor hereunder or (h) amend this Section
10.01; provided, further, that no amendment, waiver or consent shall, unless in
writing and signed by the Agent in addition to the Banks required above to take
such action, affect the rights or duties of the Agent under any Credit
Document; and provided, further, that no amendment, waiver or consent shall,
unless in writing and signed by the Guarantor in addition to any other party
required above to take such action, affect the rights or duties of the
Guarantor under any Credit Document; and provided, further, that no increase
may be made with respect to any Bank's Commitment without the consent of such
Bank.

       Section 10.02.  Notices, Etc.  All notices and other communications
provided for hereunder shall be in writing (including telecopy, telegraphic,
telex or cable communication) and mailed, telecopied, telegraphed, telexed,
cabled or delivered, if to any Bank, as specified opposite its name on Schedule
I hereto or specified pursuant to an Assignment; if to the Borrower or the
Guarantor, as specified opposite its name on Schedule II hereto; and if to
NationsBank, as Agent, as specified opposite its name on Schedule I hereto or,
as to the Borrower, the Guarantor, or the Agent, at such other address as shall
be designated by such party in a written notice to the other parties and, as to
each other party, at such other address as shall be designated by such party in
a written notice to the Borrower, the Guarantor, and the Agent.  All such
notices and communications shall, when mailed, telecopied, telegraphed, telexed
or cabled, be effective when deposited in the mails, sent by telecopier to any
party to the telecopier number as set forth herein or on Schedule I or Schedule
II (or other telecopy number specified by such party in a written notice to the
other parties hereto), delivered to the telegraph company, telexed to any party
to the telex number set forth hereinabove or on Schedule I or Schedule II (or
other telex number designated by such party in a written notice to the other
parties hereto), confirmed by telex answerback, or delivered to the cable
company, respectively, except that notices and communications to the Agent
pursuant to Article II or IX shall not be effective until received by the
Agent.

       Section 10.03.  No Waiver; Remedies.  No failure on the part of any Bank
or the Agent to exercise, and no delay in exercising, any right under any
Credit Document shall operate as a waiver thereof; nor shall any single or
partial exercise of any such right preclude any other or further exercise
thereof or the exercise of any other right.  The remedies provided in the
Credit Documents are cumulative and not exclusive of any remedies provided by
law.





                                      -49-
<PAGE>   147
       Section 10.04.  Costs, Expenses and Taxes.

       (a) The Borrower agrees to pay on demand (i) all reasonable costs
and expenses of the Agent in connection with the preparation, execution,
delivery, administration, modification and amendment of any Credit Document,
including, without limitation, the reasonable fees and out-of-pocket expenses
of counsel for the Agent with respect thereto and with respect to advising the
Agent as to its rights and responsibilities under any Credit Document, Agent's
out-of-pocket expenses associated with the negotiation and closing and (ii) all
costs and expenses, if any (including, without limitation, reasonable counsel
fees and expenses, which may include inside counsel), of the Agent and each
Bank in connection with the enforcement (whether through negotiations, legal
proceedings or otherwise) against the Borrower or the Guarantor of any Credit
Document.

       (b)    THE BORROWER AGREES, TO THE FULLEST EXTENT PERMITTED BY LAW, TO
INDEMNIFY AND HOLD HARMLESS THE AGENT, EACH CO-AGENT, THE ARRANGER &
SYNDICATION AGENT AND EACH BANK AND EACH OF THEIR RESPECTIVE DIRECTORS,
OFFICERS, EMPLOYEES AND AGENTS FROM AND AGAINST ANY AND ALL CLAIMS, DAMAGES,
LIABILITIES AND EXPENSES (INCLUDING, WITHOUT LIMITATION, REASONABLE FEES AND
DISBURSEMENTS OF COUNSEL) FOR WHICH ANY OF THEM MAY BECOME LIABLE OR WHICH MAY
BE INCURRED BY OR ASSERTED AGAINST THE AGENT, SUCH CO-AGENT, THE ARRANGER &
SYNDICATION AGENT OR SUCH BANK OR ANY SUCH DIRECTOR, OFFICER, EMPLOYEE OR AGENT
(OTHER THAN BY ANOTHER BANK OR ANY SUCCESSOR OR ASSIGN OF ANOTHER BANK), IN
EACH CASE IN CONNECTION WITH OR ARISING OUT OF OR BY REASON OF ANY
INVESTIGATION, LITIGATION, OR PROCEEDING, WHETHER OR NOT THE AGENT, SUCH CO-
AGENT, THE ARRANGER & SYNDICATION AGENT OR SUCH BANK OR ANY SUCH DIRECTOR,
OFFICER, EMPLOYEE OR AGENT IS A PARTY THERETO, ARISING OUT OF, RELATED TO OR IN
CONNECTION WITH ANY CREDIT DOCUMENT OR ANY TRANSACTION IN WHICH ANY PROCEEDS OF
ALL OR ANY PART OF THE ADVANCES ARE APPLIED (OTHER THAN ANY SUCH CLAIM, DAMAGE,
LIABILITY OR EXPENSE TO THE EXTENT ATTRIBUTABLE TO THE GROSS NEGLIGENCE OR
WILLFUL MISCONDUCT OF, OR VIOLATION OF ANY LAW OR REGULATION BY, ANY SUCH
INDEMNIFIED PARTY).

       Section 10.05.  Right of Set-off.  Upon (i) the occurrence and during
the continuance of any Event of Default and (ii) the making of the request or
the granting of the consent specified by Section 8.01 to authorize the Agent to
declare the Notes due and payable pursuant to the provisions of Section 8.01,
each Bank is hereby authorized at any time and from time to time, to the
fullest extent permitted by law, to set off and apply any and all deposits
(general or special, time or demand, provisional or final) at any time held and
other indebtedness at any time owing by such Bank to or for the credit or the
account of the Borrower or the Guarantor against any and all of the obligations





                                      -50-
<PAGE>   148
of the Borrower or the Guarantor now or hereafter existing under the Credit
Documents, irrespective of whether or not such Bank shall have made any demand
under this Agreement or such Notes and although such obligations may be
unmatured.  Each Bank agrees promptly to notify the Borrower and the Guarantor
after such set-off and application made by such Bank, provided that the failure
to give such notice shall not affect the validity of such set-off and
application.  The rights of each Bank under this Section are in addition to
other rights and remedies (including, without limitation, other rights of
set-off) which such Bank may have.

       Section 10.06.  Bank Assignments and Participations.
       
       (a)    Assignments.  Any Bank may assign to one or more banks or
other entities all or any portion of its rights and obligations under this
Agreement (including, without limitation, all or a portion of its Commitment,
the Advances owing to it, and the Notes held by it); provided, however, that
(i) each such assignment of an Assigning Bank's Commitment shall be of a
constant, and not a varying, percentage of all of such Bank's rights and
obligations under this Agreement in respect of such Commitment and such Bank
shall simultaneously assign a pro rata portion of  such Bank's rights and
obligations in respect of its Parallel Agreement Commitment so that its pro
rata percentage of each of the Commitments and the Parallel Agreement
Commitments is the same, (ii) the amount of the resulting Commitment and
Advances of the assigning Bank (unless it is assigning all its Commitment and
all of its Parallel Agreement Commitment) and the assignee Bank pursuant to
each such assignment (determined as of the date of the Assignment with respect
to such assignment) shall in no event be less than $10,000,000 and shall be an
integral multiple of $1,000,000, (iii) each such assignment shall be to an
Eligible Assignee, (iv) the parties to each such assignment shall execute and
deliver to the Agent, for its acceptance and recording in the Register, an
Assignment, together with the Note or Notes subject to such assignment, and (v)
each Eligible Assignee not already a Bank hereunder shall pay to the Agent an
assignment fee of $3000 in connection with such assignment.  Upon such
execution, delivery, acceptance and recording, from and after the effective
date specified in each Assignment, which effective date shall be at least three
Business Days after the execution thereof, (A) the assignee thereunder shall be
a party hereto for all purposes and, to the extent that rights and obligations
hereunder have been assigned to it pursuant to such Assignment, have the rights
and obligations of a Bank hereunder and (B) such Bank thereunder shall, to the
extent that rights and obligations hereunder have been assigned by it pursuant
to such Assignment, relinquish its rights and be released from its obligations
under this Agreement (and, in the case of an Assignment covering all or the
remaining portion of such Bank's rights and obligations under this Agreement,
such Bank shall cease to be a party hereto).

       (b)    Terms of Assignments.  By executing and delivering an Assignment,
the Bank thereunder and the assignee thereunder confirm to and agree with each
other and the other parties hereto the matters set forth in paragraphs 2 and 3
of such Assignment.





                                      -51-
<PAGE>   149
       (c)    The Register.  The Agent shall maintain at its address referred
to on Schedule I a copy of each Assignment delivered to and accepted by it and
a register for the recordation of the names and addresses of the Banks and the
Commitments of, and principal amount of the Advances owing to, each Bank from
time to time (the "Register").  The entries in the Register shall be conclusive
and binding for all purposes, absent manifest error, and the Borrower, the
Guarantor, the Agent, and the Banks may treat each Person whose name is
recorded in the Register as a Bank hereunder for all purposes of this
Agreement.  The Register shall be available for inspection by the Borrower, the
Guarantor, or any Bank at any reasonable time and from time to time upon
reasonable prior notice.

       (d)    Procedures.  Upon its receipt of an Assignment executed by a Bank
and an Eligible Assignee, together with the Note or Notes subject to such
assignment, the Agent shall, if such Assignment has been completed and is in
substantially the form of the attached Exhibit C, (i) accept such Assignment,
(ii) record the information contained therein in the Register, and (iii) give
prompt notice thereof to the Borrower and the Guarantor.  Within five Business
Days after its receipt of such notice, the Borrower, at its own expense, shall
execute and deliver to the Agent (x) in exchange for the surrendered A Note, a
new A Note to the order of such Eligible Assignee in an amount equal to the
Commitment assumed by it pursuant to such Assignment (without giving affect to
any B Reduction) and, if such assigning Bank has retained any Commitment
hereunder, a new A Note to the order of such Bank in an amount equal to the
Commitment retained by it hereunder (without giving affect to any B Reduction),
and (y) in exchange for any surrendered B Note, a new B Note to the order of
such Eligible Assignee in an amount equal to the B Advances assumed by it
pursuant to such Assignment and, if such assigning Bank has retained any B
Advances hereunder, a new B Note to the order of such Bank in any amount equal
to the B Advances retained by it hereunder.  Such new A Notes and B Notes shall
be dated the effective date of such Assignment and shall otherwise be in
substantially the form of the attached Exhibit A-1 or Exhibit A-2, as the case
may be.

       (e)    Participations.  Each Bank may sell participations to one or more
banks or other entities in or to all or a portion of its rights and obligations
under this Agreement (including, without limitation, all or a portion of its
Commitment, the Advances owing to it, and the Notes held by it); provided,
however, that (i) such Bank's obligations under this Agreement (including,
without limitation, its Commitment to the Borrower hereunder) shall remain
unchanged, (ii) such Bank shall remain solely responsible to the other parties
hereto for the performance of such obligations, (iii) such Bank shall remain
the holder of any such Notes for all purposes of this Agreement, (iv) the
Borrower, the Guarantor, the Agent, and the other Banks shall continue to deal
solely and directly with such Bank in connection with such Bank's rights and
obligations under this Agreement, (v) such Bank shall not require the
participant's consent to any matter under this Agreement, except for changes in
the principal amount of such Bank's Commitment, any Note payable to such Bank
in which the participant has an interest, or the aggregate Commitments,
reductions in fees or interest, the date any amount is due hereunder, or
extending the Termination Date or continuing the Commitment of such Bank
pursuant to Section 2.15 hereof, and (vi) such Bank shall give prompt





                                      -52-
<PAGE>   150
notice to the Borrower of each such participation sold by such Bank.  The
Borrower hereby agrees that participants shall have the same rights under
Sections 2.06(c), 2.10, 2.11, and 10.04 hereof as the Bank to the extent of
their respective participations.

       (f)  Assignment to Federal Reserve Bank.  Notwithstanding the
limitations set forth in paragraph (a) of this Section, any Bank may at any
time assign all or any portion of its rights under this Agreement or any Notes
payable to such Bank to a Federal Reserve Bank without the prior written
consent of the Borrower, the Guarantor, the Agent, the Co-Agents, or the
Arranger & Syndication Agent, provided that no such assignment shall release
such assigning Bank from any of its obligations hereunder or substitute any
such Federal Reserve Bank for such Bank as a party hereto.

       Section 10.07.  Governing Law.  This Agreement, the Notes and the other
Credit Documents shall be governed by, and construed in accordance with, the
laws of the State of Texas.

       Section 10.08.  Interest.

       (a)    It is the intention of the parties hereto that the Agent and each
Bank shall conform strictly to usury laws applicable to it, if any.
Accordingly, if the transactions with the Agent or any Bank contemplated hereby
would be usurious under applicable law, if any, then, in that event,
notwithstanding anything to the contrary in this Agreement, the Notes, or any
other agreement entered into in connection with or as security for this
Agreement or the Notes, it is agreed as follows:  (i) the aggregate of all
consideration which constitutes interest under applicable law that is
contracted for, taken, reserved, charged or received by the Agent or such Bank,
as the case may be, under this Agreement, the Notes, or under any other
agreement entered into in connection with or as security for this Agreement or
the Notes shall under no circumstances exceed the maximum amount allowed by
such applicable law and any excess shall be cancelled automatically and, if
theretofore paid, shall at the option of the Agent or such Bank, as the case
may be, be credited by the Agent or such Bank, as the case may be, on the
principal amount of the obligations owed to the Agent or such Bank, as the case
may be, by the Borrower or refunded by the Agent or such Bank, as the case may
be, to the Borrower, and (ii) in the event that the maturity of any Note or
other obligation payable to the Agent or such Bank, as the case may be, is
accelerated or in the event of any required or permitted prepayment, then such
consideration that constitutes interest under law applicable to the Agent or
such Bank, as the case may be, may never include more than the maximum amount
allowed by such applicable law and excess interest, if any, to the Agent or
such Bank, as the case may be, provided for in this Agreement or otherwise
shall be cancelled automatically as of the date of such acceleration or
prepayment and, if theretofore paid, shall, at the option of the Agent or such
Bank, as the case may be, be credited by the Agent or such Bank, as the case
may be, on the principal amount of the obligations owed to the Agent or such
Bank, as the case may be, by the Borrower or refunded by the Agent or such
Bank, as the case may be, to the Borrower.  To the extent that any Bank may be
subject to Texas law limiting the amount of interest





                                      -53-
<PAGE>   151
payable for its account, such Bank shall utilize the indicated (weekly) rate
ceiling from time to time in effect as provided in Article 5069-1.04 of the
Revised Civil Statutes of Texas, as amended.

       (b)    In the event that at any time the interest rate applicable to any
Advance made by any Bank would exceed the maximum non-usurious rate allowed by
applicable law, the rate of interest to accrue on the Advances by such Bank
shall be limited to the maximum non-usurious rate allowed by applicable law,
but shall accrue, to the extent permitted by law, on the principal amount of
the Advances made by such Bank from time to time outstanding, if any, at the
maximum non-usurious rate allowed by applicable law until the total amount of
interest accrued on the Advances made by such Bank equals the amount of
interest which would have accrued if the interest rates applicable to the
Advances pursuant to Article II had at all times been in effect.  In the event
that upon the final payment of the Advances made by any Bank and termination of
the Commitment of such Bank, the total amount of interest paid to such Bank
hereunder and under the Notes is less than the total amount of interest which
would have accrued if the interest rates applicable to such Advances pursuant
to Article II had at all times been in effect, then the Borrower agrees to pay
to such Bank, to the extent permitted by law, an amount equal to the excess of
(a) the lesser of (i) the amount of interest which would have accrued on such
Advances if the maximum non-usurious rate allowed by applicable law had at all
times been in effect or (ii) the amount of interest rates applicable to such
Advances pursuant to Article II had at all times been in effect over (b) the
amount of interest otherwise accrued on such Advances in accordance with this
Agreement.

       Section 10.09.  Execution in Counterparts.  This Agreement may be
executed in any number of counterparts and by different parties hereto in
separate counterparts, each of which when so executed shall be deemed to be an
original and all of which taken together shall constitute one and the same
agreement.

       Section 10.10.  Survival of Agreements, Representations and Warranties,
Etc.  All warranties, representations and covenants made by the Borrower or the
Guarantor or any officer of the Borrower or the Guarantor herein or in any
certificate or other document delivered in connection with this Agreement shall
be considered to have been relied upon by the Banks and shall survive the
issuance and delivery of the Notes and the making of the Advances regardless of
any investigation.  The indemnities and other obligations of the Borrower
contained in this Agreement, and the indemnities by the Banks in favor of the
Agent and its officers, directors, employees and agents, will survive the
repayment of the Advances and the termination of this Agreement.

       Section 10.11.  Borrower's Right to Apply Deposits.  In the event that
any Bank is placed in receivership or enters a similar proceeding, the Borrower
may, to the full extent permitted by law, make any payment due to such Bank
hereunder, to the extent of finally collected unrestricted deposits of the
Borrower in U.S. dollars held by such Bank, by giving notice to the Agent and
such Bank directing such Bank to apply such deposits to such indebtedness.  If
the amount of such deposits is insufficient to pay such indebtedness then due
and owing in full, the Borrower shall pay the balance of such insufficiency in
accordance with this Agreement.





                                      -54-
<PAGE>   152
       Section 10.12.  Confidentiality.  Each Bank agrees that it will use best
efforts, to the extent not inconsistent with practical business requirements,
not to disclose without the prior consent of the Borrower and the Guarantor
(other than to employees, auditors, accountants, counsel or other professional
advisors of the Agent or any Bank or any Bank's Affiliate) any information with
respect to the Borrower or the Guarantor or their Subsidiaries which is
furnished pursuant to this Agreement and which (i) the Borrower or the
Guarantor in good faith consider to be confidential and (ii) is either clearly
marked confidential or is designated by the Borrower or the Guarantor to the
Agent or the Banks in writing as confidential, provided that any Bank may
disclose any such information (a) as has become generally available to the
public, (b) as may be required or appropriate in any report, statement or
testimony submitted to or required by any municipal, state or Federal
regulatory body having or claiming to have jurisdiction over such Bank or
submitted to or required by the Board of Governors of the Federal Reserve
System or the Federal Deposit Insurance Corporation or similar organizations
(whether in the United States or elsewhere) or their successors, (c) as may be
required or appropriate in response to any summons or subpoena in connection
with any litigation, (d) in order to comply with any law, order, regulation or
ruling applicable to such Bank, (e) to the prospective assignee or participant
in connection with any contemplated transfer of any of the Notes or any
interest therein by such Bank, provided that such prospective assignee or
participant executes an agreement with or for the benefit of the Borrower and
the Guarantor containing provisions substantially identical to those contained
in this Section 10.12.

       Section 10.13.  Binding Effect.  This Agreement shall become effective
when it shall have been executed by the Borrower, the Guarantor and the Agent,
and when each Bank listed on the signature pages hereof has delivered an
executed counterpart hereof to the Agent, has sent to the Agent a facsimile
copy of its signature hereon or has notified the Agent that such Bank has
executed this Agreement and thereafter shall be binding upon and inure to the
benefit of the Borrower, the Guarantor, the Agent, each Bank and their
respective successors and assigns, except that the Borrower and the Guarantor
shall not have the right to assign any of their respective rights hereunder or
any interest herein without the prior written consent of the Banks.

       SECTION 10.14.  ENTIRE AGREEMENT.  PURSUANT TO SECTION 26.02 OF THE
TEXAS BUSINESS AND COMMERCE CODE, A LOAN AGREEMENT IN WHICH THE AMOUNT INVOLVED
IN THE LOAN AGREEMENT EXCEEDS $50,000 IN VALUE IS NOT ENFORCEABLE UNLESS THE
LOAN AGREEMENT IS IN WRITING AND SIGNED BY THE PARTY TO BE BOUND OR THAT
PARTY'S AUTHORIZED REPRESENTATIVE.

       THE RIGHTS AND OBLIGATIONS OF THE PARTIES TO AN AGREEMENT SUBJECT TO THE
PRECEDING PARAGRAPH SHALL BE DETERMINED SOLELY FROM THE WRITTEN LOAN AGREEMENT,
AND ANY PRIOR ORAL AGREEMENTS BETWEEN THE PARTIES ARE SUPERSEDED BY AND MERGED
INTO THE LOAN AGREEMENT.  THIS WRITTEN AGREEMENT AND THE CREDIT DOCUMENTS, AS
DEFINED IN THIS AGREEMENT, REPRESENT THE FINAL AGREEMENT AMONG





                                      -55-
<PAGE>   153
THE PARTIES AND MAY NOT BE CONTRADICTED BY EVIDENCE OF PRIOR, CONTEMPORANEOUS,
OR SUBSEQUENT ORAL AGREEMENTS OF THE PARTIES.

       Section 10.15.  Severability.  In the event that any one or more of the
provisions contained in this Agreement or in any other Credit Document should
be held invalid, illegal or unenforceable in any respect, the validity,
legality and enforceability of the remaining provisions contained herein and
therein shall not in any way be affected or impaired thereby.


                    [REMAINDER OF PAGE INTENTIONALLY BLANK]





                                      -56-
<PAGE>   154
       IN WITNESS WHEREOF, the parties hereto have caused this Agreement to be
executed by their respective officers thereunto duly authorized, as of the date
first above written.

                                           BORROWER:
                                           -------- 

                                           FINA OIL AND CHEMICAL COMPANY
                                           
                                           
                                           -------------------------------
                                           Yves Bercy
                                           Vice President & Chief
                                           Financial Officer


                                           GUARANTOR:
                                           --------- 

                                           FINA, INC.



                                           -------------------------------
                                           Yves Bercy
                                           Vice President & Chief
                                           Financial Officer


                                           AGENT:
                                           ----- 

                                           NATIONSBANK OF TEXAS, N.A.,
                                           as Agent



                                           -------------------------------
                                           Denise Ashford Smith
                                           Senior Vice President





                                      -57-
<PAGE>   155
                                           ARRANGER & SYNDICATION AGENT
                                           ----------------------------
                                           NATIONSBANC CAPITAL MARKETS, INC.



                                           ---------------------------------
                                           David E. Hunt
                                           Managing Director



Commitments                                BANKS:
-----------                                ----- 


$30,588,234                                NATIONSBANK OF TEXAS, N.A.



                                           ---------------------------------
                                           Denise Ashford Smith
                                           Senior Vice President


$26,382,353                                CIBC INC.



                                           ---------------------------------
                                           By:
                                             -------------------------------
                                           Title:
                                                ----------------------------

$26,382,353                                TEXAS COMMERCE BANK
NATIONAL ASSOCIATION



                                           ---------------------------------
                                           By:
                                             ------------------------------- 
                                           Title:
                                                ----------------------------




                                      -58-
<PAGE>   156
$18,735,294                                BANK BRUSSELS LAMBERT,
                                           NEW YORK BRANCH


                                           ------------------------------
                                           By:
                                             ----------------------------
                                           Title:
                                                -------------------------


$18,735,294                                BANQUE NATIONALE DE PARIS,
                                           HOUSTON AGENCY



                                           ------------------------------
                                           By:
                                             ----------------------------
                                           Title:
                                                -------------------------


$18,735,294                                CREDIT LYONNAIS NEW YORK BRANCH



                                           ------------------------------
                                           By:
                                             ----------------------------
                                           Title:
                                                -------------------------


$18,735,294                                THE FUJI BANK, LIMITED
                                           HOUSTON AGENCY



                                           ------------------------------
                                           By:
                                             ----------------------------
                                           Title:
                                                -------------------------
                                           





                                      -59-
<PAGE>   157
$18,735,294                                MELLON BANK, N.A.



                                           ------------------------------
                                           By:
                                             ----------------------------
                                           Title:
                                                -------------------------


$18,735,294                                SOCIETE GENERALE, SOUTHWEST
                                           AGENCY



                                           ------------------------------
                                           By:
                                             ----------------------------
                                           Title:
                                                -------------------------


$18,735,294                                THE SUMITOMO BANK, LIMITED



                                           ------------------------------
                                           By:
                                             ----------------------------
                                           Title:
                                                -------------------------


$18,735,294                                UNION BANK OF SWITZERLAND,
HOUSTON AGENCY



                                           ------------------------------
                                           By:
                                             ----------------------------
                                           Title:
                                                -------------------------



                                           ------------------------------
                                           By:
                                             ----------------------------
                                           Title:
                                                -------------------------





                                      -60-
<PAGE>   158
$15,294,118                                BAYERISCHE LANDESBANK GIROZENTRALE,
                                           CAYMAN ISLANDS BRANCH



                                           ------------------------------
                                           By:
                                             ----------------------------
                                           Title:
                                                -------------------------



                                           ------------------------------
                                           By:
                                             ----------------------------
                                           Title:
                                                -------------------------


$15,294,118                                CITICORP USA, INC.



                                           ------------------------------
                                           By:
                                             ----------------------------
                                           Title:
                                                -------------------------


$15,294,118                                CREDIT COMMERCIAL DE FRANCE



                                           ------------------------------
                                           By:
                                             ----------------------------
                                           Title:
                                                -------------------------




                                           ------------------------------
                                           By:
                                             ----------------------------
                                           Title:
                                                -------------------------





                                      -61-
<PAGE>   159
$15,294,118                                THE DAI-ICHI KANGYO BANK, LTD.
                                            NEW YORK BRANCH



                                           ------------------------------
                                           By:
                                             ----------------------------
                                           Title:
                                                -------------------------


$15,294,118                                DEN DANSKE BANK AKTIESELSKAB
                                            CAYMAN ISLANDS BRANCH



                                           ------------------------------
                                           By:
                                             ----------------------------
                                           Title:
                                                -------------------------


                                           ------------------------------
                                           By:
                                             ----------------------------
                                           Title:
                                                -------------------------


$15,294,118                                GENERALE BANK--NEW YORK BRANCH



                                           ------------------------------
                                           By:
                                             ----------------------------
                                           Title:
                                                -------------------------

=================
$325,000,000                               TOTAL COMMITMENTS





                                      -62-
<PAGE>   160
                                  EXHIBIT A-1

                               A PROMISSORY NOTE


U.S. $___________________                          Dated as of February 27, 1997


       FOR VALUE RECEIVED, the undersigned, Fina Oil and Chemical Company, a
Delaware corporation (the "Borrower"), HEREBY PROMISES TO PAY to the order of
__________________________ (the "Bank"), for the account of its Applicable
Lending Office (as defined in the Credit Agreement referred to below) or any
other office designated by the Bank the principal amount of each A Advance (as
defined below) made by the Bank to the Borrower pursuant to the Credit
Agreement (as defined below) on the date such A Advance is due and payable as
set forth in the Credit Agreement.

       The Borrower promises to pay interest on the unpaid principal amount of
each A Advance from the date of such A Advance until such principal amount is
paid in full, at such interest rates, and payable at such times, as are
specified in the Credit Agreement.

       Both principal and interest are payable in lawful money of the United
States of America to NationsBank of Texas, N.A., as Agent, at 901 Main Street,
Dallas, Texas 75202, in same day funds.  Each A Advance made by the Bank to the
Borrower and the maturity thereof, and all payments made on account of
principal thereof, shall be recorded by the Bank and, prior to any transfer
hereof, endorsed on the grid attached hereto which is part of this Promissory
Note.

       This Promissory Note is one of the A Notes referred to in, and is
subject to and entitled to the benefits of, the U.S. $325,000,000 5-Year Credit
Agreement dated as of February 27, 1997 (as it may be amended from time to time
in accordance with its terms, the "Credit Agreement") among the Borrower, Fina,
Inc., as Guarantor, the Bank, certain other banks parties thereto, CIBC Inc.
and Texas Commerce Bank National Association, as Co-Agents, NationsBanc Capital
Markets, Inc., as Arranger & Syndication Agent, and NationsBank of Texas, N.A.,
as Agent for the Bank and such other banks.  The Credit Agreement, among other
things, (i) provides for the making of advances (the "A Advances") by the Bank
to the Borrower from time to time pursuant to Section 2.01 of the Credit
Agreement in an aggregate outstanding amount not to exceed at any time the U.S.
dollar amount first above mentioned, the indebtedness of the Borrower resulting
from each such A Advance being evidenced by this Promissory Note, and (ii)
contains provisions for acceleration of the maturity hereof upon the happening
of certain stated events and also for prepayments on account of principal
hereof prior to the maturity hereof upon the terms and conditions therein
specified.  Capitalized terms used herein which are not defined herein and are
defined in the Credit Agreement are used herein as therein defined.
<PAGE>   161
       The Borrower hereby waives presentment, demand, protest, notice of
intent to accelerate, notice of acceleration and any other notice of any kind,
except as provided in the Credit Agreement.  No failure to exercise, and no
delay in exercising, any rights hereunder on the part of the holder hereof
shall operate as a waiver of such rights.

       This Promissory Note shall be governed by, and construed in accordance
with, the laws of the State of Texas (except that Tex. Rev. Civ. Stat. Ann.
Art. 5069, Ch. 15, which regulates certain revolving credit loan accounts,
shall not apply to this Note).


                                           FINA OIL AND CHEMICAL COMPANY


                                                                         
                                           ------------------------------
                                           By:                           
                                              ---------------------------
                                           Title:                        
                                                 ------------------------




                                     -2-
<PAGE>   162
                                  EXHIBIT A-2


                               B PROMISSORY NOTE


U.S. $_______________                                   Dated:  __________, 19__



       FOR VALUE RECEIVED, the undersigned, Fina Oil and Chemical Company, a
Delaware corporation (the "Borrower"), HEREBY PROMISES TO PAY to the order of
__________________________ (the "Bank") for the account of its Applicable
Lending Office (as defined in the Credit Agreement referred to below), on
___________, 199_, the principal amount of ____________________ Dollars
($__________).

       The Borrower promises to pay interest on the unpaid principal amount
hereof from the date hereof until such principal amount is paid in full, at the
interest rate and payable on the interest payment date or dates provided below:

       Interest Rate: _____% per annum (calculated on the basis of a year of
       ____ days for the actual number of days elapsed).

       Interest Payment Date or Dates: ______________________

       Both principal and interest are payable in lawful money of the United
States of America to NationsBank of Texas, N.A., as Agent, at 901 Main Street,
Dallas, Texas 75202, in same day funds.

       This Promissory Note is one of the B Notes referred to in, and is
entitled to the benefits of, the U.S. $325,000,000 5-Year Credit Agreement
dated as of February 27, 1997 (as it may be amended from time to time in
accordance with its terms, the "Credit Agreement") among the Borrower, Fina,
Inc., as Guarantor, the Bank, certain other banks parties thereto, CIBC Inc.
and Texas Commerce Bank National Association, as Co-Agents, NationsBanc Capital
Markets, Inc., as Arranger & Syndication Agent, and NationsBank of Texas, N.A.,
as Agent for the Bank and such other banks.  The Credit Agreement, among other
things, contains provisions for acceleration of the maturity hereof upon the
happening of certain stated events.  Capitalized terms used herein which are
not defined herein and are defined in the Credit Agreement are used herein as
therein defined.

       The Borrower hereby waives presentment, demand, protest, notice of
intent to accelerate, notice of acceleration and any other notice of any kind,
except as provided in the Credit Agreement.  No failure to exercise, and no
delay in exercising, any rights hereunder on the part of the holder hereof
shall operate as a waiver of such rights.
<PAGE>   163
       This Promissory Note shall be governed by, and construed in accordance
with, the laws of the State of Texas.


                                           FINA OIL AND CHEMICAL COMPANY


                                                                            
                                           ---------------------------------
                                           By:                              
                                              ------------------------------
                                           Title:                           
                                                 ---------------------------




                                     -2-
<PAGE>   164
                                  EXHIBIT B-1

                             NOTICE OF A BORROWING


                                     [Date]


NationsBank of Texas, N.A., as Agent
 for the Banks parties
 to the Credit Agreement
 referred to below
901 Main Street, 64th Floor
Dallas, Texas 75202

Attention:  Ms. Denise Ashford Smith

Ladies and Gentlemen:

       The undersigned, Fina Oil and Chemical Company (the "Borrower"), refers
to the U.S. $325,000,000 5-Year Credit Agreement dated as of February 27, 1997
(as it may be amended from time to time in accordance with its terms, the
"Credit Agreement"; the terms defined therein and not defined herein being used
herein as therein defined), among the undersigned, Fina, Inc., certain Banks
parties thereto, CIBC Inc. and Texas Commerce Bank National Association, as Co-
Agents, NationsBanc Capital Markets, Inc., as Arranger & Syndication Agent, and
NationsBank of Texas, N.A., as Agent for such Banks, and hereby gives you
notice, irrevocably, pursuant to Section 2.02 of the Credit Agreement that the
undersigned hereby requests an A Borrowing under the Credit Agreement, and in
that connection sets forth below the information relating to such A Borrowing
(the "Proposed A Borrowing") as required by Section 2.02(a) of the Credit
Agreement:

       (i)    The Business Day of the Proposed A Borrowing is ________________,
              19___.

       (ii)   The Type of A Advances comprising the Proposed A Borrowing is
              [Base Rate Advances] [Eurodollar Rate Advances].

       (iii)  The aggregate amount of the Proposed A Borrowing is
              $____________.
<PAGE>   165
NationsBank of Texas, N.A., as Agent
____________, ___
Page 2




       (iv)   The Interest Period for each A Advance made as part of the
              Proposed A Borrowing is _______ [days] [months].

       The undersigned hereby certifies that the following statements are true
on the date hereof, and will be true on the date of the Proposed A Borrowing:

              (a)    the representations and warranties contained in Article V
       of the Credit Agreement (excluding those contained in Section 5.05 and
       Section 5.06 of the Credit Agreement) are correct on and as of the date
       of the Proposed A Borrowing, before and after giving effect to the
       Proposed A Borrowing and to the application of the proceeds therefrom,
       as though made on and as of such date;

              (b)    no event has occurred and is continuing, or would result
       from the Proposed A Borrowing or from the application of the proceeds
       therefrom, which constitutes an Event of Default *[or which would
       constitute a Default]; and

              (c)    after giving effect to the Proposed A Borrowing and all
       other Borrowings which have been requested on or prior to the date of
       the Proposed A Borrowing but which have not been made prior to such
       date, the aggregate principal amount of all Borrowings will not exceed
       the aggregate of the Commitments.



                                                  Very truly yours,

                                                  FINA OIL AND CHEMICAL COMPANY


                                                                               
                                                  -----------------------------
                                                  By:                          
                                                     --------------------------
                                                  Title:                       
                                                        -----------------------





                                  
----------------------------------

     *To be included in Notices of A Borrowing in respect of A Borrowings
referred to in Section 3.03 of the Credit Agreement.
<PAGE>   166
                                  EXHIBIT B-2

                             NOTICE OF B BORROWING



                                     [Date]


NationsBank of Texas, N.A., as Agent
 for the Banks parties
 to the Credit Agreement
 referred to below
901 Main Street, 64th Floor
Dallas, Texas 75202

Attention:  Ms. Denise Ashford Smith

Ladies and Gentlemen:

       The undersigned, Fina Oil and Chemical Company (the "Borrower"), refers
to the U.S. $325,000,000 5-Year Credit Agreement dated as of February 27, 1997
(as it may be amended from time to time in accordance with its terms, the
"Credit Agreement"; the terms defined therein and not defined herein being used
herein as therein defined), among the undersigned, Fina, Inc., certain Banks
parties thereto, CIBC Inc. and Texas Commerce Bank National Association, as Co-
Agents, NationsBanc Capital Markets, Inc., as Arranger & Syndication Agent, and
NationsBank of Texas, N.A., as Agent for such Banks, and hereby gives you
notice, irrevocably, pursuant to Section 2.16 of the Credit Agreement that the
undersigned hereby requests a B Borrowing under the Credit Agreement, and in
that connection sets forth the terms on which such B Borrowing (the "Proposed B
Borrowing") is requested to be made:


       (A)    Date of B Borrowing                                               
                                           ------------------------
       (B)    Amount of B Borrowing                                             
                                           ------------------------
       (C)    Maturity Date                                                     
                                           ------------------------
       (D)    Interest Rate Basis                                               
                                           ------------------------
       (E)    Interest Payment Date(s)                                          
                                           ------------------------
       (F)                                                                      
              --------------------------   ------------------------
       (G)                                                                      
              --------------------------   ------------------------

       The undersigned hereby certifies that the following statements are true
on the date hereof, and will be true on the date of the Proposed B Borrowing:
<PAGE>   167
NationsBank of Texas, N.A., As Agent
_____________, 19__
Page 2



              (a)    the representations and warranties contained in Article V
       of the Credit Agreement (excluding those contained in Section 5.05 and
       Section 5.06 of the Credit Agreement) are correct on and as of the date
       of the Proposed B Borrowing, before and after giving effect to the
       Proposed B Borrowing and to the application of the proceeds therefrom,
       as though made on and as of such date;

              (b)    no event has occurred and is continuing, or would result
       from the Proposed B Borrowing or from the application of the proceeds
       therefrom, which constitutes a Default; and

              (c)    following the making of the Proposed B Borrowing and all
       other Borrowings to be made on the same day under the Credit Agreement,
       the aggregate principal amount of all Advances then outstanding shall
       not exceed the aggregate amount of the Commitments (computed without
       regard to any B Reduction).

       The undersigned hereby confirms that the Proposed B Borrowing is to be
made available to it in accordance with Section 2.08(a)(v) of the Credit
Agreement.



                                           Very truly yours,

                                           FINA OIL AND CHEMICAL COMPANY



                                                                                
                                           -------------------------------------
                                           By:                                  
                                              ----------------------------------
                                           Title:                               
                                                 -------------------------------
<PAGE>   168
                                   EXHIBIT C

                           ASSIGNMENT AND ACCEPTANCE

                          Dated ________________, 19__


       Reference is made to the U.S. $325,000,000 5-Year Credit Agreement dated
as of February 27, 1997 (as the same may be amended or modified from time to
time, the "Credit Agreement") among Fina Oil and Chemical Company, a Delaware
corporation (the "Borrower"), Fina, Inc., a Delaware corporation (the
"Guarantor"), the Banks, CIBC Inc. and Texas Commerce Bank National
Association, as Co-Agents, NationsBanc Capital Markets, Inc., as Arranger &
Syndication Agent, and NationsBank of Texas, N.A., as Agent.  Capitalized terms
not otherwise defined in this Assignment and Acceptance ("Assignment") shall
have the meanings assigned to them in the Credit Agreement.

       Pursuant to the terms of the Credit Agreement, ________________ wishes
to assign and delegate [(a)] ____%(1) of its rights and obligations under the
Credit Agreement in connection with its Commitment and its outstanding A
Advances and A Note [and (b) ____% of its rights under the Credit Agreement in
connection with its outstanding B Advance(s) and B Note(s)].  Therefore,
_________________ ("Assignor"), _______________ ("Assignee"), and the Agent
agree as follows:

       1.     The Assignor hereby sells and assigns and delegates to the
Assignee, and the Assignee hereby purchases and assumes from the Assignor, as
of the Effective Date (as defined below), without recourse to the Assignor and
without representation or warranty except for the representations and
warranties specifically set forth in clauses (i), (ii), and (iii) of Section 2
hereof, [(a)] a ___% interest in and to all of the Assignor's rights and
obligations under the Credit Agreement in connection with its Commitment
(without regard to any B Reduction), its outstanding A Advances and its A Note,
[and (b) ____% of its rights under the Credit Agreement in connection with its
outstanding B Advance(s) and B Note(s)].

       2.     The Assignor (i) represents and warrants that, prior to executing
this Assignment and Acceptance, its Commitment (without regard to any B
Reduction) is $_____________, and the aggregate outstanding principal amount of
A Advances owed to it by the Borrower is $_____________; (ii) represents and
warrants that it is the legal and beneficial owner of the interest being
assigned by it hereunder and that such interest is free and clear of any
adverse claim; (iii) makes no representation or warranty and assumes no
responsibility with respect to any statements, warranties, or representations
made in or in connection with the Credit Agreement or any other Credit Document
or the execution, legality, validity, enforceability, genuineness, sufficiency,
or value of the Credit Agreement or any other Credit Document or any other
instrument or document furnished pursuant thereto; (iv) makes no representation
or warranty and assumes no responsibility with respect

                                  
----------------------------------

        (1)    Specify percentage in no more than 5 decimal points.
<PAGE>   169
to the financial condition of the Borrower or the Guarantor or the performance
or observance by the Borrower or the Guarantor of any of their respective
obligations under the Credit Agreement or any other Credit Document or any
other instrument or document furnished pursuant thereto; and (v) attaches the
Note(s) referred to in paragraph 1 above and requests that the Agent [(i)]
exchange such A Note for [a] new A Note dated ____________, 19__ in the
principal amount of $______________ payable to the order of the Assignee[, and
a new A Note dated _____________, 19___ in the principal amount of $__________
payable to the order of Assignor][, and (ii) exchange such B Note(s) for new B
Note(s) dated __________, 19__ in the principal amount(s) of $__________,
$__________, and $__________ payable to the order of the Assignee and new B
Note(s) dated __________, 19__ in the principal amount(s) of $__________,
$__________, and $__________].

       3.     The Assignee (i) confirms that it has received a copy of the
Credit Agreement, together with copies of the financial statements referred to
in Section 5.05 thereof and such other documents and information as it has
deemed appropriate to make its own credit analysis and decision to enter into
this Assignment; (ii) agrees that it will, independently and without reliance
upon the Agent, the Assignor, or any other Bank and based on such documents and
information as it shall deem appropriate at the time, continue to make its own
credit decisions in taking or not taking action under the Credit Agreement;
(iii) appoints and authorizes the Agent to take such action as agent on its
behalf and to exercise such powers under the Credit Agreement as are delegated
to the Agent by the terms thereof, together with such powers as are reasonably
incidental thereto; (iv) agrees that it will perform in accordance with their
terms all of the obligations which by the terms of the Credit Agreement are
required to be performed by it as a Bank; (v) specifies as its Domestic Lending
Office (and address for notices) and Eurodollar Lending Office the offices set
forth beneath its name on the signature pages hereof; (vi) attaches the forms
prescribed by the Internal Revenue Service of the United States certifying as
to the Assignee's status for purposes of determining exemption from United
States withholding taxes with respect to all payments to be made to the
Assignee under the Credit Agreement and its Note(s) or such other documents as
are necessary to indicate that all such payments are subject to such rates at a
rate reduced by an applicable tax treaty(2), and (vii) represents that it is an
Eligible Assignee.





                                  
----------------------------------

        (2)    If the Assignee is organized under the laws of a jurisdiction
outside the United States.
<PAGE>   170
       4.     The effective date for this Assignment and Acceptance shall be
________________ (the "Effective Date")(3) and following the execution of this
Assignment, the Agent will record it.

       5.     Upon such recording, and as of the Effective Date, (i) the
Assignee shall be a party to the Credit Agreement for all purposes, and, to the
extent provided in this Assignment, have the rights and obligations of a Bank
thereunder and (ii) the Assignor shall, to the extent provided in this
Assignment, relinquish its rights (other than rights against the Borrower
pursuant to Section 10.04 of the Credit Agreement, which shall survive this
assignment) and be released from its obligations under the Credit Agreement.

       6.     Upon such recording, from and after the Effective Date, the Agent
shall make all payments under the Credit Agreement and the Note(s) in respect
of the interest assigned hereby (including, without limitation, all payments of
principal, interest, and fees) to the Assignee.  The Assignor and Assignee
shall make all appropriate adjustments in payments under the Credit Agreement
and the Note(s) for periods prior to the Effective Date directly between
themselves.

       7.     This Assignment shall be governed by, and construed and enforced
in accordance with, the laws of the State of Texas.





                                  
----------------------------------

        (3)      See Section 10.06(a).  Such date shall be at least three
Business Days after the execution of this Assignment.





                                      -3-
<PAGE>   171
       The parties hereto have caused this Assignment to be duly executed as of
the date first above written.


                                   [ASSIGNOR]


                                   By:                                          
                                      ------------------------------------------
                                   Name:                                        
                                        ----------------------------------------
                                   Title:                                       
                                         ---------------------------------------

                                   Address:                                     
                                                  ------------------------------
                                                                                
                                                  ------------------------------
                                                                                
                                                  ------------------------------



                                   Attention:                                   
                                                  ------------------------------
                                   Telecopy:                                    
                                                  ------------------------------
                                   Telephone:                                   
                                                  ------------------------------

                                   [ASSIGNEE]
                                   Domestic Lending Office:
                                   ----------------------- 


                                   By:                                          
                                      ------------------------------------------
                                   Name:                                        
                                        ----------------------------------------
                                   Title:                                       
                                         ---------------------------------------

                                   Address:                                     
                                                  ------------------------------
                                                                                
                                                  ------------------------------
                                                                                
                                                  ------------------------------



                                   Attention:                                   
                                                  ------------------------------
                                   Telecopy:                                    
                                                  ------------------------------
                                   Telephone:                                   
                                                  ------------------------------





                                      -4-
<PAGE>   172
                                   Eurodollar Lending Office:
                                   ------------------------- 


                                   By:                                          
                                      ------------------------------------------
                                   Name:                                        
                                        ----------------------------------------
                                   Title:                                       
                                         ---------------------------------------

                                   Address:                                     
                                                  ------------------------------
                                                                                
                                                  ------------------------------
                                                                                
                                                  ------------------------------



                                   Attention:                                   
                                                  ------------------------------
                                   Telecopy:                                    
                                                  ------------------------------
                                   Telephone:                                   
                                                  ------------------------------


                                   NATIONSBANK OF TEXAS, N.A.,
                                   as Agent for Itself and the Banks


                                   By:                                          
                                      ------------------------------------------
                                   Name:                                        
                                        ----------------------------------------
                                   Title:                                       
                                         ---------------------------------------

                                   Address:       901 Main Street
                                                  Dallas, Texas 75202

                                   Attention:  Ms. Denise Ashford Smith
                                   Telecopy:  (214) 508-1285
                                   Telephone: (214) 508-1261





                                      -5-
<PAGE>   173
                                   EXHIBIT D

                    [FORM OF OPINION OF GENERAL COUNSEL FOR
                        THE BORROWER AND THE GUARANTOR]


                               February 27, 1997


To each of the lenders parties to
  the Credit Agreement herein
  described and  to NationsBank
  of Texas, N.A., as Agent

Ladies and Gentlemen:

This opinion is furnished to you pursuant to Section 3.01 of the U.S.
$325,000,000 5-Year Credit Agreement dated as of February 27, 1995 (the "Credit
Agreement"), among Fina Oil and Chemical Company, as borrower (the "Borrower"),
Fina, Inc., as guarantor (the "Guarantor"), the banks parties thereto (the
"Banks"), CIBC Inc. and Texas Commerce Bank National Association, as Co-Agents,
NationsBanc Capital Markets, Inc., as Arranger & Syndication Agent, and
NationsBank of Texas, N.A., as Agent for the Banks.  Terms defined in the
Credit Agreement are used herein as therein defined.

       [Opinion format of rendering counsel to be supplied by such counsel.]

                                   Opinions:

       1.     Each of the Borrower and the Guarantor is a corporation duly
organized, validly existing and in good standing under the laws of the State of
Delaware.

       2.     Each of (i) the execution, delivery and performance by each of
the Borrower and the Guarantor of the Credit Agreement, (ii) the execution,
delivery and performance by the Borrower of the A Notes and the other Notes to
be executed by the Borrower, and (iii) the consummation of the transactions
contemplated by the Credit Agreement, are within the corporate powers of the
Borrower and the Guarantor, respectively, have been duly authorized by all
necessary corporate action, do not contravene (x) the Certificate of
Incorporation or the By-laws of the Borrower or the Guarantor, respectively, or
(y) any law, rule or regulation applicable to the Borrower or the Guarantor
(including, without limitation, Regulation X of the Board of Governors of the
Federal Reserve System) or (z) any contractual or legal restriction and will
not result in or require the creation or imposition of any Lien prohibited by
the Credit Agreement.  With respect to the Notes to be executed after the date
hereof by the Borrower, this
<PAGE>   174
February 27, 1997
Page 2



opinion is limited to laws, rules and regulations as in force and applied on
the date hereof, the Certificate of Incorporation and the Bylaws of the
Borrower, and restrictions in effect on the date hereof.  The Credit Agreement
has been duly executed and delivered by the Borrower and the Guarantor, and the
A Notes have been duly executed and delivered by the Borrower.

       3.     No authorization, approval or other action by, and no notice to
or filing with, any governmental authority or regulatory body is required for
the due execution, delivery and performance by the Borrower or the Guarantor of
the Credit Agreement, and (in the case of the Borrower) the respective Notes or
the consummation of the transactions contemplated by the Credit Agreement.

       4.     The A Notes executed by the Borrower constitute, and each Note
hereafter executed by the Borrower will constitute, a legal, valid and binding
obligation of the Borrower, enforceable against the Borrower in accordance with
its terms.  The Credit Agreement executed by the Borrower and the Guarantor
constitutes legal, valid and binding obligations of the Borrower and the
Guarantor, respectively, enforceable against the Borrower and the Guarantor in
accordance with its terms.

       5.     There are no pending or overtly threatened actions or proceedings
against the Borrower, the Guarantor or any of their respective Subsidiaries
before any court, governmental agency or arbitrator which purport to affect the
legality, validity, binding effect or enforceability of the Credit Agreement or
any of the Notes or which could reasonably be expected to have a materially
adverse effect upon the financial condition or operations of the Borrower and
its Subsidiaries taken as a whole, or the Guarantor and its Subsidiaries taken
as a whole.

       6.     Neither the Borrower nor the Guarantor is an "investment company"
or a company "controlled" by an "investment company" within the meaning of the
Investment Company Act of 1940, as amended.  Neither the Borrower nor the
Guarantor is a "holding company", or a "subsidiary company" of a "holding
company", or an "affiliate" of a "holding company" or of a "subsidiary company"
of a "holding company", or a "public utility" within the meaning of the Public
Utility Holding Company Act of 1935, as amended.



                                                   Very truly yours,
<PAGE>   175
                                   EXHIBIT E

                  FORM OF OPINION OF SPECIAL COUNSEL TO AGENT


                               February 27, 1997


To each of the lenders parties
  to the Credit Agreement
  herein described and to
  NationsBank of Texas, N.A.,
  as Agent

Ladies and Gentlemen:

We have acted as special counsel to NationsBank of Texas, N.A., acting for
itself and as Agent, in connection with the preparation, execution and delivery
of the U.S. $325,000,000 5-Year Credit Agreement dated as of February 27, 1997
(the "Credit Agreement"), among Fina Oil and Chemical Company, as borrower (the
"Borrower"), Fina, Inc., as guarantor (the "Guarantor"), CIBC Inc. and Texas
Commerce Bank National Association, as Co-Agents, NationsBanc Capital Markets,
Inc., as Arranger & Syndication Agent, NationsBank of Texas, N.A., as agent
(the "Agent"), and each of you named as Banks thereunder.  Terms defined in the
Credit Agreement are used herein as therein defined.

In that connection, we have examined the following documents:

              (1)    counterparts of the Credit Agreement, executed by the
       Agent, the Borrower, and the Guarantor, respectively;

              (2)    the A Notes dated as of February 27, 1997 of the Borrower
       payable to the order of each Bank party to the Credit Agreement as of
       the date hereof (the "A Notes"); and

              (3)    the opinion dated February 27, 1997 of Cullen M. Godfrey,
       General Counsel for each of the Borrower and the Guarantor ("Opinion").

In our examination of the documents referred to above, we have assumed the
authenticity of all such documents submitted to us as originals, the
genuineness of all signatures and the conformity to the originals of all such
documents submitted to us as copies.  We have also assumed that each of the
Borrower, the Guarantor, the Banks and the Agent has duly executed and
delivered, with all necessary power and authority (corporate and otherwise),
the Credit
<PAGE>   176
February 27, 1997
Page 2



Agreement, that the Borrower has duly executed and delivered, with all
necessary power and authority (corporate and otherwise), the A Notes.  We have
also assumed that no Bank has requested that the Opinion required by Section
3.01(d) of the Credit Agreement contain any other matters not contained in the
form of opinion set forth as Exhibit D to the Credit Agreement.

Based upon the foregoing examination of documents and assumptions and upon such
other investigation as we have deemed necessary, we are of the opinion that the
A Notes and the Opinion, are substantially responsive to the requirements of
the Credit Agreement.

This opinion is solely for the benefit of the Banks, the Agent, their
respective successors, assigns, participants and other transferees and may be
relied upon only by such Persons.

                                           Very truly yours,



                                           Bracewell & Patterson, L.L.P.
<PAGE>   177
                                   EXHIBIT F


                          FORM OF ACCESSION AGREEMENT


       [NAME OF BANK]            , hereby agrees with Fina Oil and Chemical
Company, as Borrower, Fina, Inc., as Guarantor, and NationsBank of Texas, N.A.,
as Agent under  the U.S. $325,000,000 5-Year Credit Agreement dated as of
February 27, 1997 (as it may be amended from time to time in accordance with
its terms, the "Credit Agreement") among the Borrower, the Guarantor, the Banks
parties thereto, CIBC Inc. and Texas Commerce Bank National Association, as
Co-Agents, NationsBanc Capital Markets, Inc., as Arranger & Syndication Agent,
and NationsBank of Texas, N.A., as Agent for the Banks (as such agreement is
amended from time to time in accordance with its terms, the "Credit Agreement";
capitalized terms used herein and not otherwise defined having the meanings set
forth therein), as follows:

       The undersigned hereby agrees and confirms that, as of the date hereof,
it (a) intends to be a Bank party to the Credit Agreement with a Commitment of
$____________ in connection with the proposed increase of the aggregate
Commitments pursunt to Section 2.15 of the Credit Agreement to $__________, and
undertakes to perform all the obligations expressed therein as a Bank; (b) has
received a copy of the Credit Agreement, together with copies of the financial
statements referred to in Section 5.05 thereof and such other documents and
information as it has deemed appropriate to make its own credit analysis and
decision to enter into this Accession Agreement and become a Bank under the
Credit Agreement; (c) will, independently and without reliance upon the Agent
or any Bank, and based on such documents and information as it shall deem
appropriate at the time, continue to make its own credit decisions in taking or
not taking action under the Credit Agreement; (d) appoints and authorizes the
Agent to take such action as agent on its behalf and to exercise such powers
under the Credit Agreement as are delegated to the Agent by the terms thereof,
together with such powers as are reasonably incidental thereto; (e) agrees that
it will perform in accordance with their terms all of the obligations which by
the terms of the Credit Agreement are required to be performed by it as a Bank;
(f) specifies as its Domestic Lending Office (and address for notices) and
Eurodollar Lending Office the offices set forth beneath its name on the
signature pages hereof; (g) attaches the forms prescribed by the Internal
Revenue Service of the United States certifying as to its status for purposes
of determining exemption from United States withholding taxes with respect to
all payments to be made to it under the Credit Agreement and its Note(s) or
such other documents as are necessary to indicate that all such payments are
subject to such rates at a rate reduced by an applicable tax treaty(1), and (h)
represents that it is an Eligible Assignee.

       The effective date for this Accession Agreement shall be the date the
related increase in the aggregate Commitments becomes effective in accordance
with the terms of Section 2.15 of the Credit Agreement (the "Effective Date")
and following the execution of this Accession Agreement,





--------------------

        (1)      If the New Bank is organized under the laws of a jurisdiction
outside the United States.
<PAGE>   178
the Agent will record it.  Upon such recording, and as of the Effective Date,
(i) the undersigned shall be a Bank party to the Credit Agreement for all
purposes, and, to the extent of its Commitment, shall have the rights and
obligations of a Bank thereunder.

       This Accession Agreement shall be construed as a contract governed in
accordance with the laws of the State of Texas.

       IN WITNESS WHEREOF this Accession Agreement was executed and delivered
as of the ___ day of _________, ____.



                                           [NAME OF NEW BANK]



                                                                               
                                           ------------------------------------
                                           By:                                 
                                              ---------------------------------
                                           Title:                              
                                                 ------------------------------
                                                                               
                                                                               
                                           Domestic Lending Office:            
                                           -----------------------             
                                                                               
                                           Address:                            
                                                         ----------------------
                                                                               
                                                         ----------------------
                                                                               
                                           Attention:                          
                                                         ----------------------
                                           Telecopy:                           
                                                         ----------------------
                                           Telephone:                          
                                                         ----------------------
                                                                               
                                                                               
                                           Eurodollar Lending Office:          
                                           -------------------------           
                                                                               
                                           Address:                            
                                                         ----------------------
                                                                               
                                                         ----------------------
                                                                               
                                           Attention:                          
                                                         ----------------------
                                           Telecopy:                           
                                                         ----------------------
                                           Telephone:                          
                                                         ----------------------
<PAGE>   179
Acknowledged and Agreed By:

FINA OIL AND CHEMICAL COMPANY


                                   
-----------------------------------
By:                                
   --------------------------------
Title:                             
      -----------------------------


FINA, INC.


-----------------------------------
By:                                
   --------------------------------
Title:                             
      -----------------------------


NATIONSBANK OF TEXAS, N.A.



-----------------------------------
By:                                
   --------------------------------
Title:                             
      -----------------------------





                                      -3-
<PAGE>   180
                                   EXHIBIT G


                   FORM OF CONSENT TO INCREASE OF COMMITMENT


       [NAME OF BANK]             , hereby agrees with Fina Oil and Chemical
Company, as Borrower, Fina, Inc., as Guarantor, and NationsBank of Texas, N.A.,
as Agent under  the U.S. $325,000,000 5-Year Credit Agreement dated as of
February 27, 1997 (as it may be amended from time to time in accordance with
its terms, the "Credit Agreement") among the Borrower, the Guarantor, the
undersigned and the other Banks parties thereto, CIBC Inc. and Texas Commerce
Bank National Association, as Co-Agents, NationsBanc Capital Markets, Inc., as
Arranger & Syndication Agent, and NationsBank of Texas, N.A., as Agent for the
Banks (as such agreement is amended from time to time in accordance with its
terms, the "Credit Agreement"; capitalized terms used herein and not otherwise
defined having the meanings set forth therein), as follows:

       The undersigned hereby agrees and confirms that, as of the date hereof,
it  intends to increase its Commitment under the Credit Agreement to
$____________ in connection with the proposed increase of the aggregate
Commitments pursunt to Section 2.15 of the Credit Agreement to $__________.

       The effective date for this Consent and for the increase of the
undersigned's Commitment as set forth in the preceding paragraph shall be the
date the related increase in the aggregate Commitments becomes effective in
accordance with the terms of Section 2.15 of the Credit Agreement (the
"Effective Date").

       This Consent shall be construed as a contract governed in accordance
with the laws of the State of Texas.

       IN WITNESS WHEREOF this Consent was executed and delivered as of the ___
day of _________, ____.


                                           [NAME OF BANK]



                                                                              
                                           -----------------------------------
                                           By:                                
                                               -------------------------------
                                           Title:                             
                                                 -----------------------------
                                                                              




<PAGE>   181
Acknowledged and Agreed By:

FINA OIL AND CHEMICAL COMPANY


                                
--------------------------------
By:                             
   -----------------------------
Title:                          
      --------------------------


FINA, INC.


--------------------------------
By:                             
   -----------------------------
Title:                          
      --------------------------


NATIONSBANK OF TEXAS, N.A.



--------------------------------
By:                             
   -----------------------------
Title:                          
      --------------------------





                                      -2-
<PAGE>   182
                                                                   EXHIBIT (10b)

                                                                  Execution Copy


                  FIRST AMENDED AND RESTATED CREDIT AGREEMENT

         This First Amended and Restated Credit Agreement dated as of February
26, 1998 (this "Amendment") is by and between Fina Oil and Chemical Company, a
Delaware corporation (the "Borrower"), Fina, Inc., a Delaware corporation (the
"Guarantor"), the Banks party hereto,  CIBC Inc. and Chase Bank of Texas,
National Association (formerly known as Texas Commerce Bank National
Association), as Co-Agents, NationsBanc Montgomery Securities LLC (formerly
known as NationsBanc Capital Markets, Inc.), as Arranger & Syndication Agent,
and NationsBank of Texas, N.A., as Agent.

                                  INTRODUCTION

         A.      Pursuant to the U.S.$100,000,000 Credit Agreement dated as of
February 27, 1997, by and among the Borrower, the Guarantor, the lenders party
thereto (the "Original Banks"), the Arranger & Syndication Agent, and the Agent
(the "Credit Agreement"), the Original Banks agreed to provide advances to the
Borrower pursuant to a revolving credit facility in an aggregate principal
amount outstanding at any time of up to U.S.$100,000,000.  As of the date of
this Amendment there are no Advances (as defined in the Credit Agreement)
outstanding.

         B.      The Borrower has requested that (i) the revolving credit
facility under the Credit Agreement be extended for an additional 364-day
period, (ii) as contemplated pursuant to Section 2.15 of the Credit Agreement
as in effect prior to the date of this Amendment, the aggregate amount of the
Commitments under the Credit Agreement be increased to U.S. $130,000,000 and
the aggregate amount of the Parallel Agreement Commitments  (as defined in the
Credit Agreement) under the Parallel Agreement  (as defined in the Credit
Agreement) be increased to U.S. $420,000,000, and (iii) certain other
amendments be made to the terms of the Credit Agreement.

         C.      The Sumitomo Bank, Limited ("Sumitomo"), an Original Bank, has
elected not to renew its Commitment under the Credit Agreement and Credit
Communal de Belgique --New York Branch has agreed (i) to provide a Commitment
under the Credit Agreement equal to the former Commitment of Sumitomo and (ii)
to assume the Parallel Agreement Commitment of Sumitomo under the Parallel
Agreement as in effect on the date hereof pursuant to an assignment and
assumption agreement delivered as of the date hereof under the Parallel
Agreement.

         D.      Each of Deutsche Bank AG New York Branch and/or Cayman Islands
Branch, Istituto Bancario San Paolo di Torini SpA, and SunTrust Bank, Atlanta
have agreed to become a new Bank under the Credit Agreement and a new bank
under the Parallel Agreement, and certain of the Original Banks have agreed to
increase their respective Commitments under the Credit Agreement and their
respective Parallel Agreement
<PAGE>   183
Commitments under the Parallel Agreement, as contemplated by Section 2.15 of
the Credit Agreement.

         E.      For the sake of administrative convenience the parties hereto
have elected to effect the increase in the aggregate Commitments under the
Credit Agreement through this Amendment instead of using the procedures set
forth in Section 2.15 of the Credit Agreement and to confirm through this
Amendment that Sumitomo will no longer be a Bank under the Credit Agreement
after the date of this Amendment except to the extent certain of its
obligations under the Credit Agreement survive in accordance with the terms
thereof.

         F.      Upon the effectiveness of this Amendment, the Credit Agreement
is hereby restated in its entirety to read as set forth in the Credit Agreement
with the amendments contained herein.

         THEREFORE, in consideration of the premises and the mutual agreements,
representations and warranties set forth herein, and for other good and
valuable consideration, the parties hereto agree as follows:

         Section 1.  Definitions; References.  Unless otherwise defined in this
Amendment, each capitalized term used in this Amendment has the meaning given
to such term in the Credit Agreement.

         Section 2.  Amendment of the Credit Agreement.

         (a)     Section 1.01.  Section 1.01 of the Credit Agreement is amended
by restating the definitions for the terms "Agent's Fee Letter," "Banks,"
"Commitments," "Co-Agent," "Reference Banks," and "Termination Date" in their
entirety, and a new definition for the term "First Amendment Agreement" is
added in appropriate alphabetical order, as follows:

                 "Agent's Fee Letter" means the letter agreement dated as of
         January 14, 1998 among the Arranger & Syndication Agent, the Agent,
         and the Borrower, as it may be amended from time to time in accordance
         with its terms.

                 "Banks" means the lenders listed on the signature pages of the
         First Amendment Agreement under the heading "Banks" and each other
         Person that becomes a Bank pursuant to an Assignment.

                 "Co-Agent" means either CIBC Inc. or Chase Bank of Texas,
         National Association in its capacity as co- agent pursuant to Article
         IX hereof, and "Co-Agents" means suchs banks collectively.

                 "Commitment" of any Bank means at any time the amount set
         forth as the "Commitment" of such Bank on the signature pages of the
         First Amendment

                                     -2-

<PAGE>   184
         Agreement, or if such Bank has executed an Assignment or a Consent to
         Increase of Commitment, then the amount set forth as the "Commitment"
         of such Bank therein, or if such Bank is a New Bank, then the amount
         set forth as the "Commitment of such Bank in the Accession Agreement
         executed by such Bank, in each case as such amount may be terminated
         or reduced pursuant to Section 2.04 or Section 8.01.

                 "First Amendment Agreement" means the First Amended and
         Restated Credit Agreement dated as of February 26, 1998 among the
         Borrower, the Guarantor, the Banks, the Arranger & Syndication Agent,
         and the Agent.

                 "Reference Banks" means NationsBank, CIBC Inc. and Chase Bank
         of Texas, National Association.

                 "Termination Date" means February 25, 1999, or the earlier
         date of termination in whole of the Commitments pursuant to Section
         2.04 or 8.01.

         (b)     Section 10.08.  Section 10.08 of the Credit Agreement is
amended by restating the last sentence of paragraph (a) thereof in its entirety
as follows:

         To the extent that any Bank may be subject to Texas law limiting the
         amount of interest  payable for its account, such Bank hereby elects
         to determine the applicable rate ceiling under Texas law by the
         indicated (weekly) rate ceiling from time to time in effect, subject
         to each such Bank's right subsequently to change such method in
         accordance with applicable law.

         (c)     Schedule I.  Schedule I attached to the Credit Agreement is
hereby replaced in its entirety with Schedule I attached to this Amendment.

         (d)     Exhibits.  Exhibit A-1 is replaced in its entirety with
Exhibit A-1 attached to this Amendment, and each of the other Exhibits to the
Credit Agreement is hereby amended by (i) changing each reference therein to
"NationsBanc Capital Markets, Inc." to "NationsBanc Montgomery Securities LLC",
and (ii) changing each reference therein to "Texas Commerce Bank National
Association" to "Chase Bank of Texas, National Association".

         Section 3.  Representations and Warranties.  Each of the Borrower and
the Guarantor represents and warrants to the Banks and the Agent that:

         (a)     all representations and warranties set forth in the Credit
Agreement, as amended by this Amendment, and in any other Credit Document are
true and correct as of the date of this Amendment;





                                      -3-
<PAGE>   185
         (b)     the execution, delivery and performance of the Credit
Agreement, as amended by this Amendment, are within the power and authority of
the Borrower and have been duly authorized by appropriate proceedings.  The
Credit Agreement as so amended constitutes a valid legally binding agreement of
the Borrower and the Guarantor enforceable in accordance with its terms; and

         (c)     as of the date of this Amendment, no Default has occurred and
is continuing.

         Section 4.  Effectiveness.  This Amendment shall become effective as
of the date hereof when the Agent shall have received the following:

         (a)     a counterpart of this Amendment duly executed by Borrower, the
Guarantor, each Bank, and the Arranger & Syndication Agent each of the parties
hereto and new Notes as described on Annex A to this Amendment;

         (b)     a certificate of the Secretary or an Assistant Secretary of
the Borrower certifying the name and true signature of the officer of the
Borrower authorized to sign this Amendment, in form and substance satisfactory
to the Agent;

         (c)     a certificate of the Secretary or an Assistant Secretary of
the Guarantor certifying the name and true signature of the officer of the
Guarantor authorized to sign this Amendment, in form and substance satisfactory
to the Agent;

         (d)     an opinion of counsel to the Borrower and the Guarantor in
form and substance satisfactory to the Agent regarding the enforceability of
this Amendment and the Notes to be executed in connection herewith;

         (e)     for the ratable benefit of each of the Original Banks (based
on their respective Commitments in effect prior to the effectiveness of this
Amendment), all accrued but unpaid fees or interest or other amounts owing
under the Credit Agreement prior to giving effect to this Amendment;

         (f)     documentation effecting the assignment of Sumitomo's Parallel
Agreement Commitment and the pro rata increase of the Parallel Agreement in
accordance with the provisions of Section 2.15 of the Parallel Agreement, duly
executed by each of the required parties thereto; and

         (g)     for the account of the Agent, the fees referred to in the
Agent's Fee Letter which are payable on the date this Amendment becomes
effective, and the fees of legal counsel for the Agent (as notified to the
Borrower) incurred in connection with this Amendment and the related increase
in the Parallel Agreement.





                                      -4-
<PAGE>   186
         Section 5.  Choice of Law.   This Amendment shall be governed by and
construed and enforced in accordance with the laws of the State of Texas.  The
parties hereto agree that Chapter 346 of the Texas Finance Code, which replaced
former Tex. Rev. Civ. Stat. Ann. Art. 5069, Chapter 15 and which regulates
certain revolving credit loan accounts, shall not apply to the transactions
contemplated by the Credit Agreement, as amended by this Amendment, and any
Note executed in connection therewith.

         Section 6.  Counterparts.  This Amendment may be signed in any number
of counterparts, each of which shall constitute one and the same instrument.

         Section 7.  INTEGRATION.  THE CREDIT AGREEMENT, AS AMENDED BY THIS
AMENDMENT, TOGETHER WITH THE OTHER CREDIT DOCUMENTS CONSTITUTES THE ENTIRE
AGREEMENT BETWEEN THE PARTIES RELATING TO THE FINANCING TRANSACTION
CONTEMPLATED THEREBY AND SUPERSEDES ALL PRIOR UNDERSTANDINGS AND AGREEMENTS,
WHETHER WRITTEN OR ORAL, BETWEEN THE PARTIES HERETO CONCERNING THE TRANSACTIONS
PROVIDED FOR HEREIN AND THEREIN.



                    [REMAINDER OF PAGE INTENTIONALLY BLANK]





                                      -5-
<PAGE>   187
         IN WITNESS WHEREOF, the parties hereto have caused this Agreement to
be executed by their respective officers thereunto duly authorized, as of the
date first above written.


                                                   BORROWER:
                                                   

                                                   FINA OIL AND CHEMICAL COMPANY



                                                   -----------------------------
                                                   Geoffroy Petit
                                                   Vice President & Chief
                                                     Financial Officer


                                                   GUARANTOR:
                                                   

                                                   FINA, INC.



                                                   -----------------------------
                                                   Geoffroy Petit
                                                   Vice President & Chief
                                                     Financial Officer


                                                   AGENT:
                                                   

                                                   NATIONSBANK OF TEXAS, N.A.,
                                                    as Agent



                                                   -----------------------------
                                                   Denise Ashford Smith
                                                   Senior Vice President





                                      -6-
<PAGE>   188

                                                   ARRANGER & SYNDICATION AGENT
                                                   

                                                   NATIONSBANC MONTGOMERY
                                                   SECURITIES LLC



                                                   -----------------------------
                                                   David E. Hunt
                                                   Managing Director


COMMITMENTS:                                       BANKS:

$10,470,591                                        NATIONSBANK OF TEXAS, N.A.



                                                   -----------------------------
                                                   Denise Ashford Smith
                                                   Senior Vice President


$8,941,176                                         CHASE BANK OF TEXAS,
                                                   NATIONAL ASSOCIATION



                                                   -----------------------------
                                                   By:
                                                       -------------------------
                                                   Title: 
                                                          ----------------------


$8,941,176                                         GENERALE BANK--NEW YORK 
                                                   BRANCH



                                                   -----------------------------
                                                   By:
                                                       -------------------------
                                                   Title:
                                                          ----------------------


                                                   -----------------------------
                                                   By:
                                                       -------------------------
                                                   Title:
                                                          ----------------------





                                      -7-
<PAGE>   189
$8,941,176                                         MELLON BANK, N.A.



                                                   -----------------------------
                                                   By:
                                                       -------------------------
                                                   Title:
                                                          ----------------------


$8,117,647                                         CIBC INC.



                                                   -----------------------------
                                                   By:                          
                                                       -------------------------
                                                   Title:                       
                                                          ----------------------


$6,941,176                                         BANQUE NATIONALE DE PARIS,
                                                   HOUSTON AGENCY


                                                   -----------------------------
                                                   By:                          
                                                       -------------------------
                                                   Title:                       
                                                          ----------------------

$6,941,176                                         CITICORP USA, INC.


                                                   -----------------------------
                                                   By:                          
                                                       -------------------------
                                                   Title:                       
                                                          ----------------------

$5,764,706                                         BANK BRUSSELS LAMBERT,
                                                   NEW YORK BRANCH


                                                   -----------------------------
                                                   By:                          
                                                       -------------------------
                                                   Title:                       
                                                          ----------------------

                                      -8-
<PAGE>   190
$5,764,706                                         CREDIT COMMUNAL DE BELGIQUE--
                                                   NEW YORK BRANCH


                                                   -----------------------------
                                                   By:                          
                                                       -------------------------
                                                   Title:                       
                                                          ----------------------


$5,764,706                                         CREDIT LYONNAIS  
                                                   NEW YORK BRANCH


                                                   -----------------------------
                                                   By:                          
                                                       -------------------------
                                                   Title:                       
                                                          ----------------------





$5,764,706                                         DEUTCHE BANK AG
                                                   NEW YORK BRANCH AND/OR
                                                   CAYMAN ISLANDS BRANCH



                                                   -----------------------------
                                                   By:                          
                                                       -------------------------
                                                   Title:                       
                                                          ----------------------

                                                   -----------------------------
                                                   By:                          
                                                       -------------------------
                                                   Title:                       
                                                          ----------------------


$5,764,706                                         THE FUJI BANK, LIMITED--
                                                   HOUSTON AGENCY


                                                   -----------------------------
                                                   By:                          
                                                       -------------------------
                                                   Title:                       
                                                          ----------------------





                                      -9-
<PAGE>   191
$5,764,706                                         ISTITUTO BANCARIO SAN PAOLO
                                                   DI TORINO SpA

                                                   -----------------------------
                                                   By:                          
                                                       -------------------------
                                                   Title:                       
                                                          ----------------------


                                                   -----------------------------
                                                   By:                          
                                                       -------------------------
                                                   Title:                       
                                                          ----------------------


$5,764,706                                         SOCIETE GENERALE, SOUTHWEST
                                                   AGENCY


                                                   -----------------------------
                                                   By:                          
                                                       -------------------------
                                                   Title:                       
                                                          ----------------------


$5,764,706                                         SUNTRUST  BANK, ATLANTA


                                                   -----------------------------
                                                   By:                          
                                                       -------------------------
                                                   Title:                       
                                                          ----------------------


                                                   -----------------------------
                                                   By:                          
                                                       -------------------------
                                                   Title:                       
                                                          ----------------------





                                      -10-
<PAGE>   192
$5,764,706                                         UNION BANK OF SWITZERLAND,
                                                   HOUSTON AGENCY


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$4,705,882                                         BAYERISCHE LANDESBANK
                                                   GIROZENTRALE,
                                                   CAYMAN ISLANDS BRANCH

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$4,705,882                                         CREDIT COMMERCIAL DE FRANCE


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                                      -11-
<PAGE>   193
$4,705,882                                        THE DAI-ICHI KANGYO BANK,LTD.
                                                  NEW YORK BRANCH


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$4,705,882                                        DEN DANSKE BANK AKTIESELSKAB
                                                  CAYMAN ISLANDS BRANCH


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$130,000,000                                      TOTAL COMMITMENTS



ACKNOWLEDGED AND AGREED BY:

THE SUMITOMO BANK, LIMITED



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                                      -12-
<PAGE>   194
                                    ANNEX A

                     NOTES TO BE ISSUED IN CONNECTION WITH
                  FIRST AMENDED AND RESTATED CREDIT AGREEMENT

Notes for Banks with Increased Commitments:

A Promissory Note dated February 26, 1998 executed by the Borrower in favor of
NationsBank of Texas, N.A. in the amount of $10,470,591.

A Promissory Note dated February 26, 1998 executed by the Borrower in favor of
Chase Bank of Texas, National Association in the amount of $8,941,176.

A Promissory Note dated February 26, 1998 executed by the Borrower in favor of
Generale Bank--New York Branch in the amount of $8,941,176.

A Promissory Note dated February 26, 1998 executed by the Borrower in favor of
Mellon Bank, N.A. in the amount of $8,941,175.

A Promissory Note dated February 26, 1998 executed by the Borrower in favor of
Banque Nationale de Paris, Houston Agency in the amount of $6,941,176.

A Promissory Note dated February 26, 1998 executed by the Borrower in favor of
Citicorp USA, Inc. in the amount of $6,941,175.

Notes for New Banks:

A Promissory Note dated February 26, 1998 executed by the Borrower in favor of
Deutsche Bank AG New York Branch and/or Cayman Islands Branch in the amount of
$5,764,706.

A Promissory Note dated February 26, 1998 executed by the Borrower in favor of
Istituto Bancario San Paolo di Torini SpA in the amount of $5,764,706.

A Promissory Note dated February 26, 1998 executed by the Borrower in favor of
SunTrust Bank, Atlanta in the amount of $5,764,706.

Note for Replacement Bank:

A Promissory Note dated February 26, 1998 executed by the Borrower in favor of
Credit Communal de Belgique--New York Branch in the amount of $5,764,706.1