<PAGE>
                                                                   EXHIBIT 10.14
 
                      "PAGES WHERE CONFIDENTIAL TREATMENT HAS BEEN REQUESTED ARE
                                 STAMPED "CONFIDENTIAL TREATMENT REQUESTED.  THE
                REDACTED MATERIAL HAS BEEN SEPARATELY FILED WITH THE COMMISSION;
                                  THE APPROPRIATE SECTION HAS BEEN MARKED AT THE
                           APPROPRIATE PLACE AND IN THE MARGIN WITH A STAR (*)."

                                                                          Hawaii
                                                                                
                        REFINERY PRODUCT SALE AGREEMENT
                        -------------------------------

          THIS REFINERY PRODUCT SALE AGREEMENT (the "Agreement") is made and
entered into effective the 1st day of September, 1996, by and between WARREN
PETROLEUM COMPANY, LIMITED PARTNERSHIP, a Delaware limited partnership with
offices at 13430 Northwest Freeway, Suite 1200, Houston, Texas 77040-6095
(hereinafter referred to as "WPC"), and CHEVRON PRODUCTS COMPANY, A DIVISION OF
CHEVRON U.S.A. INC., a Pennsylvania corporation with offices at 91-480 Malakole
Street, Kapolei, Hawaii (hereinafter referred to as "CPC").

                                  WITNESSETH:

          WHEREAS, Chevron U.S.A. Inc. ("CUSA") and NGC Corporation ("NGC") have
entered into certain agreements (the "Merger Agreements") pursuant to which CUSA
would contribute certain gas gathering, processing, and other midstream assets
and related liabilities of CUSA's Warren Petroleum Company division ("Warren")
and natural gas business unit division to a corporation to be formed which NGC
would then be merged into (the "Merger");

          WHEREAS, immediately subsequent to the Merger, the gas gathering,
processing and other midstream assets and related liabilities of Warren will be
transferred to WPC;

          WHEREAS, Warren previously purchased from CPC and CPC sold to Warren
all of the Refinery Products and certain Offspec Refinery Products produced at
CPC's Refinery and both CPC and WPC desire that such relationship continue;

          WHEREAS, CPC has quantities of Refinery Products available for sale
from its Refinery (as defined in Article I, below) that it desires to sell to
WPC, and WPC desires to purchase such Refinery Products from CPC; and

          WHEREAS, CPC desires that WPC maintain the same level of service that
was previously provided to it by Warren and WPC desires to continue such level
of service.

          NOW, THEREFORE, in consideration of the premises and for the mutual
benefit of the parties as well as for other good and valuable consideration, WPC
and CPC agree as follows:

                                   ARTICLE I
                                  DEFINITIONS
                                  -----------
<PAGE>
 
     1.1 As used in this Agreement, the following terms shall have the following
meanings:

     Accounting Period shall mean a period of one (1) Month commencing at 12:01
     a.m. local time on the first Day of a calendar Month and ending at 12:01
     a.m. local time on the first Day of the next succeeding Month.

     Affiliate shall mean any Person that directly or indirectly through one or
     more intermediaries, controls or is controlled by or is under common
     control with the Person specified.  The term "control" (including the terms
     "controlled by" or "under common control with") means the possession,
     directly or indirectly, of the power to direct or cause the direction of
     the management and policies of a Person, whether through ownership, by
     contract, or otherwise.  Any Person shall be deemed to be an Affiliate of
     any specified Person if such Person owns fifty percent (50%) or more of the
     voting securities of the specified Person, if the specified Person owns
     fifty percent (50%) or more of the voting securities of such Person, or if
     fifty percent (50%) or more of the voting securities of the specified
     Person and such Person are under common control.

     Arbitration Notice shall have the meaning specified in Section 13.1(d)
     hereinafter.

     Bankruptcy Event shall mean the occurrence of one or more of the following
     events with respect to a Party: (A) the entry of a decree or order for
     relief against a Party by a court of competent jurisdiction in any
     involuntary case brought against a Party under any bankruptcy insolvency or
     other similar law (collectively, "Debtor Relief Laws") generally affecting
     the rights of creditors and relief of debtors now or hereafter in effect,
     (B) the appointment of a receiver, liquidator, assignee, custodian,
     trustee, sequestrator, or other similar agent under applicable Debtor
     Relief Laws for a Party or for any substantial part of its assets or
     property, (C) the ordering of the winding up or liquidation of a Party's
     affairs, (D) the filing of a petition in any such involuntary bankruptcy
     case, which petition remains undismissed for a period of 180 Days or which
     is not dismissed or suspended pursuant to Section 305 of the Federal
     Bankruptcy Code (or any corresponding provision of any future United States
     bankruptcy law), (E) the commencement by a Party of a voluntary case under
     any applicable Debtor Relief Law now or hereafter in effect, (F) the
     consent by a Party to the entry of an order for relief in an involuntary
     case under any such law or to the appointment of or the taking of
     possession by a receiver, liquidator, assignee, trustee, custodian,
     sequestrator or other similar agent under any applicable Debtor Relief Laws
     for a Party or for any substantial part of its assets or property, or (G)
     the making by a Party of any general assignment for the benefit of its
     creditors.

     Barrel shall mean forty-two (42) U. S. Gallons.

     Base Rate shall mean the lesser of (i) two percent (2%) above the per annum
     rate of interest announced from time to time as the "prime rate" for
     commercial loans by First 

                                       2
<PAGE>
 
     National Bank of Chicago, as such "prime rate" may change from time to
     time, or (ii) the maximum applicable non-usurious rate of interest.

     Business Day shall mean a Day on which Federal Reserve member banks in New
     York City are open for business.

     Day or Daily shall mean a twenty-four (24) hour period commencing 12:01
     a.m. local time and extending until 12:01 a.m. local time on the following
     Day.

     Delivery Point(s) shall have the meaning specified in Section 6.2
     hereinafter.

     Effective Date shall mean September 1, 1996.

     Force Majeure shall have the meaning specified in Section 12.2 hereinafter.

     Gallon shall mean the unit of volume used for the purpose of measurement of
     liquid.  One (1) U.S. liquid Gallon contains two hundred thirty-one (231)
     cubic inches when the liquid is at a temperature of sixty degrees
     Fahrenheit (60 degrees F) and at the vapor pressure of the liquid being
     measured.

     Month or Monthly shall mean a period commencing at 12:01 a.m. local time on
     the first Day of a calendar Month and extending until 12:01 a.m. local time
     on the first Day of the next succeeding calendar Month.

     Netback Price shall mean the price obtained by WPC in an arm's length sale
     of Refinery Products to a third Person who is not an Affiliate of WPC less
     Transportation Costs that are reasonably incurred in connection therewith.

     New Taxes shall mean any Taxes enacted and effective after the Effective
     Date, including that portion of any Taxes or New Taxes that constitutes an
     increase either in rate or breadth of coverage.

     Offspec Refinery Products shall have the meaning specified in Section 7.1
     hereinafter.

     Party shall mean individually either CPC or WPC (including their respective
     successors and permitted assigns); collectively, the "Parties."

     Person shall mean any individual, corporation, partnership, limited
     liability company, association, joint venture, trust, or other organization
     of any nature or kind.

     Propane shall mean a liquid hydrocarbon stream which meets the
     specifications set forth in Exhibit "A".

     Refinery shall mean the refinery owned by CPC and situated in Hawaii.

                                       3

<PAGE>
 
     Refinery Products shall mean Propane and those other light end streams
     identified on Exhibit "A" and produced from the Refinery.

     Taxes shall mean any and all ad valorem, property, occupation, severance,
     production, extraction, first use, conservation, Btu or energy, gathering,
     transport, pipeline, utility, gross receipts, gas or oil revenue, gas or
     oil import, privilege, sales, use, consumption, excise, lease, transaction,
     environmental, and other taxes, governmental charges, duties, licenses,
     fees, permits, and assessments.

     Transportation Costs shall mean all costs and expenses reasonably incurred
     in connection with the transportation of  Refinery Product(s) hereunder,
     including, without limitation, rail car, barges, and truck costs, Refinery
     Product losses that occur during transportation for reasons other than the
     negligence or willful misconduct of WPC and all costs and expenses
     reasonably incurred in loading, unloading, transporting, terminaling,
     storing (if required), and handling such Refinery Products.  It is
     understood and agreed that Transportation Costs shall not include any
     portion of WPC's general and administrative costs and expenses.

     Year shall mean a period of twelve (12) consecutive Months commencing from
     the Effective Date.

          1.2  Other Definitions.  Other terms may be defined elsewhere in the
text of this Agreement and shall have the meanings indicated throughout this
Agreement.

                                   ARTICLE II
                         REPRESENTATIONS AND WARRANTIES
                         ------------------------------

          2.1  CPC hereby represents and warrants to WPC that on and as of the
date hereof:

          (a)  It has all requisite power and authority to carry on the business
               in which it is engaged and to perform its respective obligations
               under this Agreement;

          (b)  The execution and delivery of this Agreement have been duly
               authorized and approved by all requisite corporate action;

          (c)  It has all requisite power and authority to enter into this
               Agreement and perform its obligations hereunder;

          (d)  The execution and delivery of this Agreement does not, and
               consummation of the transactions contemplated herein will not,
               violate any of the material provisions of its organizational
               documents, any material agreement pursuant to which CPC or its
               properties are bound or, to its knowledge, any material laws
               applicable to CPC; and

                                       4

<PAGE>

                                              "Confidential Treatment Requested.
                                                  The redacted material has been
                                          separately filed with the Commission."

 
          (e)  This Agreement is valid, binding, and enforceable against it in
               accordance with its terms, subject to bankruptcy, moratorium,
               insolvency, and other laws generally affecting creditors' rights
               and general principles of equity (whether applied in a proceeding
               in a court of law or equity).

2.2  WPC hereby represents and warrants to CPC that on and as of the date
hereof:

          (a)  It has all requisite power and authority to carry on the business
               in which it is engaged and to perform its respective obligations
               under this Agreement;

          (b)  The execution and delivery of this Agreement have been duly
               authorized and approved by all requisite partnership action;

          (c)  It has all requisite power and authority to enter into this
               Agreement and perform its obligations hereunder;

          (d)  The execution and delivery of this Agreement does not, and
               consummation of the transactions contemplated herein will not,
               violate any of the material provisions of its organizational
               documents, any material agreement pursuant to which WPC or its
               properties are bound or, to its knowledge, any material laws
               applicable to WPC;  and

          (e)  This Agreement is valid, binding, and enforceable against it in
               accordance with its terms, subject to bankruptcy, moratorium,
               insolvency, and other laws generally affecting creditors' rights
               and general principles of equity (whether applied in a proceeding
               in a court of law or equity).

                                  ARTICLE III
                                      TERM
                                      ----

          3.1  Unless otherwise provided herein, this Agreement shall remain in
* full force and effect for a period of REDACTED Years from the Effective Date
  hereof and shall continue from Year to Year thereafter unless terminated by
* either Party hereto at the end of such least REDACTED Year period or any
  Yearly anniversary thereafter by giving the other Party at ninety (90) Days,
  but not more than one hundred eighty (180) Days, advance written notice of its
  intention to so terminate.

          3.2 Notwithstanding Section 3.1 above, this Agreement may be
terminated as follows:

                                       5

<PAGE>
 
          (a)  By the non-defaulting Party, upon thirty (30) Days written notice
               to the other Party, after it has been determined through the
               alternative dispute resolution procedures of Article XIII that a
               Material Default has occurred in the performance of a Party's
               obligations hereunder (it being understood that, for purposes of
               the foregoing, "Material Default" shall mean that the arbitrators
               have determined that (i) in consequence of such default, the
               objectives of this Agreement (as expressed in the Master Alliance
               Agreement of even date herewith by and among CUSA, WPC and
               others) are not being met and (ii) the defaulting Party failed to
               take the steps necessary to accomplish such objectives);

          (b)  By a Party, in the event the other Party is dissolved (unless the
               successor to such dissolved Party or its assets is an Affiliate
               of CUSA or WPC.); or

          (c)  By a Party, if a Bankruptcy Event occurs with respect to the
               other Party.

          In the event the Refinery is sold to a third Person not affiliated
with CPC, the reference to the Master Alliance Agreement set forth in Section
3.2(a), above, shall be inapplicable.

          3.3  It is agreed and understood that CPC, in its sole discretion, may
permanently close the Refinery at any time during the term of this Agreement.
Upon such permanent closure, CPC and WPC shall be relieved of any further
obligations under this Agreement, if CPC has provided WPC with written notice of
such closure at least one hundred and eighty (180) Days prior to the date of
such closure.

          3.4  Upon the termination of this Agreement, any monies due and owing
either Party shall be paid to the other Party pursuant to the terms hereof and
any refunds due either Party shall be made at the earliest possible time, and in
any event no later than sixty (60) Days after the expiration or termination of
this Agreement.  All audit rights shall survive for the period prescribed by
Section 11.7.

          3.5  Termination of this Agreement hereunder shall be cumulative of
any other rights or remedies that the terminating Party may have in connection
with such termination, including, but not limited to, damages and injunctive
relief.

                                   ARTICLE IV
                                    QUANTITY
                                    --------

          4.1  Subject to the terms and provisions hereof, WPC agrees to
purchase from CPC and CPC agrees to sell to WPC all Refinery Products.

          4.2  Solely for planning purposes, on the first Business Day of each
Month during the term of this Agreement, CPC shall provide WPC with a three (3)
Month rolling estimate  

                                       6

<PAGE>
                                              "Confidential Treatment Requested.
                                                  The redacted material has been
                                          separately filed with the Commission."

 
of the volumes of Refinery Products that it will have available for sale.  The
Parties shall use every reasonable effort to deliver and receive, as applicable,
Refinery Products on a ratable Daily basis.

                                   ARTICLE V
                                     PRICE
                                     -----
                                        
          5.1  Except as otherwise provided herein, WPC shall pay CPC for the
* Refinery Products purchased hereunder REDACTED of the Netback Price. WPC shall
  use every reasonable effort to obtain the highest Netback Price for Refinery
  Products. Notwithstanding the foregoing, it is understood and agreed that
  WPC's share of the Netback Price received from the disposition of Refinery
* Products (i.e., REDACTED), shall never be less than REDACTED per Gallon of the
  Refinery Products delivered to WPC at the Delivery Point.

          5.2  Every five (5) Years after the Effective Date of this Agreement,
either Party shall have the option to open this Agreement solely for the purpose
of renegotiating the pricing provisions hereof.  To exercise such option, a
Party at least ninety (90) Days before the expiration of such five (5) Year
period must provide to the other Party written notification (the "Renegotiation
Notice") of its desire to renegotiate the price for the Refinery Products sold
and purchased hereunder.  In any such renegotiations, the Parties shall continue
to recognize that the price for Refinery Products must reflect market prices for
Refinery Products in Hawaii.  If, after negotiating in good faith for a period
of ninety (90) Days following the date of the Renegotiation Notice, the Parties
are unable to agree upon a mutually acceptable price for such Refinery
Product(s), the matter shall be submitted to the alternative dispute resolution
procedures as provided in Article XIII hereof.  During the period while
negotiations are ongoing until (i) a new price is agreed to or (ii) a new price
is established as provided herein, the price for the Refinery Product sold and
purchased hereunder shall be determined in accordance with the pricing formula
that was applicable immediately prior to the date of the Renegotiation Notice.
If a new price is established under this Section 5.2, whether by renegotiation,
arbitration, or otherwise, such new price shall be effective as of, and shall,
if necessary, be made retroactive to, the first Day of the applicable five (5)
Year period immediately following the Renegotiation Notice, plus interest
thereon at the Base Rate.

          5.3  In the event conditions change such that this Agreement causes,
or could reasonably be expected to cause, a material long term economic or
operational hardship to either Party, upon the written request of either Party,
CPC and WPC shall meet to renegotiate in good faith such burdensome terms and
provisions so as to make them fair and equitable.  Such renegotiations shall
occur within thirty (30) Days of the date of the non-requesting Party's receipt
of such written request for such renegotiations.  If the parties are unable to
agree on new provisions to replace such burdensome terms and provisions within
ninety (90) Days of the non-requesting Party's receipt of such written request,
the matter shall be submitted to the alternative dispute resolution procedures
set forth in Article XIII hereof.  It is 

                                       7

<PAGE>
 
understood and agreed that the rights granted in this Section 5.3 can only be
used by a Party to commence good faith renegotiations once during each Year
during the term hereof. If new provisions are agreed upon under this Section
5.3, whether by renegotiation, arbitration, or otherwise, such new provisions
shall be effective as of, and shall, if necessary, be made retroactive to, the
date on which the notice commencing renegotiations under this Section 5.3 was
given, plus interest thereon at the Base Rate.

                                   ARTICLE VI
                                   DELIVERIES
                                   ----------

          6.1  The Refinery Products to be sold hereunder by CPC to WPC shall be
delivered by CPC at the Delivery Points in Section 6.2.

          6.2  The point(s) of delivery for Refinery Product sold and delivered
hereunder (hereinafter the "Delivery Point(s)") shall be determined as follows:

          (a)  In the event delivery is to be to or from a pipeline, the
               Delivery Point shall be located, and delivery of Refinery Product
               shall be deemed to occur, at the point at which Refinery Product
               passes the pipeline meter. If pipeline delivery is by in-line
               inventory transfer, delivery shall be deemed to occur on the date
               and time that the relevant pipeline carrier advises CPC and WPC,
               by product transfer order, book transfer, or letter of transfer,
               that Refinery Product shall be transferred to CPC's account, and
               the Delivery Point shall be the location of the Refinery Product
               in the pipeline of the pipeline carrier on the Day and time that
               such in-line transfer of Refinery Product is deemed to occur. The
               Parties hereto understand and agree that WPC has no control over
               the operations of the pipeline carrier and therefore cannot
               control when Refinery Product transfer to WPC's account by the
               pipeline carrier will, in fact, occur.

          (b)  In the event delivery is to be by a rail car, truck, or barge
               whether owned, operated, leased, or hired by WPC or CPC, the
               Delivery Point shall be located, and delivery of Refinery Product
               shall be deemed to occur, (i) at the point at which the Refinery
               Product passes through the flange connecting the rail car, truck,
               or barge which is used to receive the Refinery Product, as long
               as such rail car, truck, or barge is immediately released by the
               Refinery to WPC for transport, or (ii) if the rail car, truck, or
               barge is not immediately released to WPC for transport, at the
               point at which such rail car, truck, or barge is released to WPC
               for transport, whichever is later.

     6.3  Title to and risk of loss associated with the Refinery Products
delivered hereunder shall pass from CPC to WPC upon the commencement of the
delivery of such Refinery Products at the Delivery Points, unless such Refinery
Products are rejected in accordance with Article VII.  WPC shall be responsible
for all risk of loss, damage, or liability to the extent that any such loss,
liability, or damage arises from acts or omissions 

                                       8

<PAGE>
 
occurring after the commencement of physical delivery of the Refinery Product at
and downstream of the Delivery Point(s), unless such Refinery Products are
rejected in accordance with Article VII.

     6.4  The following rules shall be applicable to the transportation and
loading of Refinery Products at the Delivery Point:

          (a)  If rail cars subject to payment of demurrage or any other similar
               charges to a third Person not affiliated with either Party are
               used to transport Refinery Products from the Delivery Point, CPC
               agrees to  load and start the relevant cars on the return trip in
               accordance with the detention policy of the owner or operator of
               such rail car equipment and CPC further agrees to pay any and all
               such charges that may be due thereunder.
 
          (b)  CPC shall be liable for the payment of invoices from the railroad
               for demurrage and hazardous materials storage charges incurred by
               WPC as the prepaid shipper due to CPC's inability to receive a
               rail car and/or have a rail car placed on CPC's siding; and

          (c)  Rail cars shall not be diverted while in transit except upon
               prior written authorization of WPC.  Any charge incurred by WPC
               for the diversion of rail cars by CPC shall be for the account of
               CPC.

          (d)  If WPC's owned or leased trucks are used to transport Refinery
               Products from the Delivery Point, CPC agrees to load immediately
               upon arrival at the Delivery Point, and CPC's failure to do so
               shall render CPC liable to WPC for damages incurred as a result
               of such delay.

          (e)  For Refinery Products purchased hereunder, CPC will be liable for
               all rail car shortages claimed by WPC in excess of one percent
               (1%) of the net Gallons reflected on the bill of lading and
               acknowledged by the railroad agent's signature prior to
               unloading; provided, however, that such shortages, if any, are
               reported in writing to CPC within twenty-four (24) hours after
               delivery by the carrier and prior to the unloading of the
               shipment in which the relevant shortage occurs.  WPC shall ask
               CPC for permission to unload, and CPC, at its expense, shall have
               the right to inspect each car at its destination within forty-
               eight (48) hours after receipt of written notice of such
               shortage.  All demurrage charges arising from the failure of CPC
               to release the car for unloading within such forty-eight (48)
               hour period shall be paid by CPC.  Similarly, CPC shall be liable
               for all truck shortages claimed by WPC in excess of three percent
               (3%) of the net Gallons reflected on the bill of lading;
               provided, however, that such shortages, if any, are noted on the
               delivery ticket and acknowledged by the truck driver's signature
               prior to unloading.  The 

                                       9

<PAGE>
 
               failure of WPC to observe this provision or any action by WPC
               which impedes identification of an alleged defect shall operate
               as a waiver of WPC's rights to make any such claim.

     Notwithstanding the foregoing, if the detention and/or demurrage charges
     set forth above are insufficient to cover any such charges paid by WPC to
     such third Person not affiliated with WPC, CPC shall reimburse WPC for such
     amounts.

     6.5  If, CPC uses a rail car, truck, or barge leased by WPC for purposes
other than those contemplated by WPC's lease, CPC shall be responsible for, and
agrees to indemnify and hold WPC harmless from and against, all costs,
liabilities, and expenses arising out of, or in any way associated with, CPC's
use of such equipment, including, but not limited to, cleaning and inspection
costs and additional rental fees for such equipment and/or for other equipment
required to be leased as a result of CPC's use.

                                  ARTICLE VII
                                    QUALITY
                                    -------

     7.1  All Refinery Products sold by CPC and purchased by WPC hereunder shall
meet the specifications set forth in Exhibit A, attached hereto and made a part
hereof.  WPC shall have the right to reject any Refinery Product which fails to
meet such quality specifications ("Offspec Refinery Product").  All costs
associated with the return and/or disposal of Offspec Refinery Product shall be
borne by CPC.

     7.2  Should the Refinery Products delivered hereunder to WPC, or to WPC's
designated representative for the account of WPC, fail at any time to conform to
the specifications set forth in Exhibit A, either Party shall notify the other
Party of any such failure, and CPC immediately shall undertake and diligently
pursue such acts as may be necessary to correct such failure, including
treatment to the extent such treatment is economical in CPC's opinion, so as to
deliver Refinery Product conforming to the specifications set forth above; but
nothing contained in this Article VII or any other part of this Agreement shall
be construed to affect WPC's right, at any time and from time to time, to reject
any Refinery Product not conforming to said specifications and to refuse or
suspend receipt until it is established to WPC's reasonable satisfaction that
subsequent deliveries of Refinery Product will conform to said specifications.
The term of this Agreement shall not be extended by the length of time of any
period or periods when deliveries have been rejected, refused, or suspended as
provided for herein.  Notwithstanding the foregoing, the knowing acceptance by
WPC of any Offspec Refinery Product  shall constitute a waiver by WPC of any and
all other rights and remedies available to WPC under this Agreement or otherwise
with respect to CPC's tender of such Offspec Refinery Product, and all risk of
loss, damage or liability arising out of WPC's ownership, control , possession,
or use of such Offspec Refinery Product shall pass to and be borne by WPC.  If
it is subsequently determined that WPC unknowingly accepted Offspec Refinery
Products, the Parties will mutually agree upon a discounted price for such
Offspec Refinery Products to reflect their diminution in value from Refinery
Products meeting the specifications hereof.  If the Parties are unable to agree
on a 

                                      10

<PAGE>
 
mutually acceptable discount price for such Offspec Refinery Products, the
matter shall be subjected to the alternative dispute resolution procedures set
forth in Article XIII hereunder.  CPC agrees to INDEMNIFY and HOLD HARMLESS WPC,
its Affiliates, and their respective officers, directors, employees, agents, and
contractors, from all actual losses, costs, expenses, claims (including, without
limitation, personal injury or property damage claims), damages, and causes of
action, including, without limitation, reasonable attorneys' fees and costs of
court (collectively, the "Losses") incurred by WPC, such Persons, or such
Affiliates arising out of, or in any way associated with, the delivery to WPC of
Propane that fails to meet the specifications set forth in Exhibit A and is
unknowingly accepted by WPC.

                                  ARTICLE VIII
                               WARRANTY OF TITLE
                               -----------------

     8.1  CPC warrants title to all Refinery Products sold and delivered by it
to WPC, and further warrants that CPC has the right to sell such Refinery
Products and that such Refinery Products meet the quality specifications as set
forth herein and are free from all liens, claims or other charges.  THERE ARE,
HOWEVER, NO OTHER WARRANTIES OF ANY KIND WHATSOEVER, EITHER EXPRESS OR IMPLIED,
INCLUDING, WITHOUT LIMITATION, ANY WARRANTY OF FITNESS FOR A PARTICULAR PURPOSE,
MERCHANTABILITY, CONFORMITY TO MODELS OR SAMPLES, OR AGAINST INFRINGEMENT OF ANY
PATENT, TRADEMARK, COPYRIGHT, OR OTHERWISE, AND ALL SUCH WARRANTIES ARE HEREBY
EXPRESSLY DISCLAIMED BY CPC AND EXCLUDED FROM THIS AGREEMENT.

                                   ARTICLE IX
                                     TAXES
                                     -----

     9.1  CPC shall be liable for and shall pay, or cause to be paid, or
reimburse WPC, if WPC has paid, all Taxes (other than environmental Taxes, which
environmental Taxes include, without limitation, Taxes imposed under Sections
4611, 4612, 4661, 4662, 4771, and 4772 and successor sections of the Internal
Revenue Code) applicable to the Refinery Product sold hereunder upstream of the
Delivery Point(s).  If WPC is required to remit such Tax, the amount thereof
shall be deducted from any sums becoming due to CPC hereunder.  WPC shall be
liable for and shall pay, cause to be paid, or reimburse CPC, if CPC has paid,
all environmental Taxes and all Taxes applicable to the sale and/or delivery of
Refinery Product hereunder at and downstream of the Delivery Point(s) including
any Taxes imposed or collected by a taxing authority with jurisdiction over WPC,
provided, however, when laws, ordinances or regulations permit or impose upon
CPC the obligation to collect or pay Taxes applicable to the sale and/or
delivery of Refinery Product hereunder at the Delivery Point, CPC shall collect
all such Taxes from WPC, which shall be in addition to the applicable Price, and
remit the same to the appropriate governmental authority, unless WPC furnishes a
certificate of exemption.  CPC SHALL INDEMNIFY, DEFEND, AND HOLD WPC HARMLESS
FROM AND AGAINST ANY LIABILITY WITH RESPECT TO THE TAXES FOR WHICH CPC IS
LIABLE.

                                      11

<PAGE>
 
     9.2  To claim an exemption from payment of a Tax, a Party shall provide a
certificate of exemption or other reasonably satisfactory evidence of exemption
from any Tax, and each Party agrees to cooperate with the other Party in
obtaining any such exemption.  In addition, WPC has provided CPC with, and CPC
acknowledges receipt of, the disclosure statement from WPC (as set forth in
Section 4101 of the Internal Revenue Code of 1986).

                                   ARTICLE X
                            MEASUREMENT AND ANALYSES
                            ------------------------

     10.1 On all deliveries into or out of rail cars, the quantity shall be
determined by official tank car capacity tables or slip tube gauges in
accordance with Gas Processors Association ("GPA") Publication 8162, latest
revision.  On all deliveries into or out of truck equipment, quantities shall be
determined by meter, rotary gauge or weighing, in accordance with GPA
Publications 8162 and 8186, latest revision.  On all deliveries into or out of
pipelines, quantities shall be determined by pipeline meter in accordance with
the America Petroleum Institute ("API") Manual of Petroleum Measurement
Standards.  For raw make mixtures, volumes of the component products shall be
determined (where practical) on a mass (pound) measurement basis in accordance
with the latest edition of GPA Publications 8173 and 8182.  On all deliveries
into or out of shore tanks, quantities shall be determined either meter or gauge
from a static tank in accordance with the API Manual of Petroleum Measurement
Standards and based upon the practice of the relevant terminal.  All quantities
shall be corrected to standard conditions of sixty degrees Fahrenheit (60
degrees F) and equilibrium vapor pressure in accordance with the API Manual of
Petroleum Measurement Standards, Chapter 14, Section B. The quantity and quality
of Refinery Product covered by this Agreement shall be measured according to the
current versions of the applicable standards of API and the American Society for
Testing Materials, if available. Each Party shall be entitled to have its
representatives present during all loadings, unloadings, tests, and measurements
involving Refinery Product delivered hereunder. If the Parties cannot agree on
measurement or quality tests results, the measurements and quality tests
required to determine the volume of receipts or shipments or the conformity of
the Refinery Product delivered to the specifications set forth herein shall be
made by an independent inspector selected jointly by the Parties, the cost of
which shall be shared equally by the Parties.

                                   ARTICLE XI
                              BILLING AND PAYMENT
                              -------------------

     11.1 After delivery of Refinery Products  hereunder, CPC shall submit a
statement to WPC by facsimile transmission setting forth the quantity of each
Refinery Product delivered to WPC.  By not later than thirty (30) Days after the
receipt of CPC's statement, WPC shall provide CPC with a statement setting forth
the price or Netback Price, as applicable, of such Refinery Products, the amount
due CPC for such Refinery Products, and such other information and detail as may
be mutually agreeable to the Parties, along with payment for such Refinery
Products, which shall be remitted by wire transfer of funds into an account
designated by CPC.  If the Day on which any payment is due is not a Business
Day, then the relevant payment shall be due upon the immediately  preceding
Business Day, except if such 

                                      12

<PAGE>
 
payment due date is a Sunday or Monday, then the relevant payment shall be due
upon the immediately succeeding Business Day.

     11.2 If CPC or WPC should fail to remit any amounts in full when due as
required hereunder, or if any adjustments are made under this Agreement,
including, without limitation, adjustments as the result of the conclusion of
any audits or as a result of the resolution of a billing dispute, interest on
the unpaid portion shall accrue from the date upon which such payment should
have been made hereunder until paid in full at the Base Rate.    All such
accrued interest shall be added to the amount reflected as being owed hereunder
by either CPC or WPC, as the case may be, on the next invoice or by separate
invoice.

     11.3 If a good faith dispute arises as to the amount payable in any
statement, the amount not in dispute shall be paid.  If either Party elects to
withhold any payment otherwise due as a consequence of the good faith dispute,
the withholding Party shall provide the other Party with written notice of  its
reasons for withholding payment, and shall simultaneously place the disputed
amount into an escrow account at a mutually acceptable commercial bank, pending
resolution of the dispute.  Any such dispute shall be resolved in accordance
with the alternative dispute resolution procedures of Article XIII.  The
performance of both Parties under this Agreement shall continue pending the
outcome of such procedures.  If it is subsequently determined, whether by mutual
agreement of the Parties or otherwise, that the withholding Party is required to
pay all or any portion of the disputed amounts to the other Party, the
withholding Party, in addition to paying over such amounts, shall also pay
interest accrued on such amounts from the original due date until paid, at the
Base Rate.

     11.4 No retroactive adjustments may be made for any overcharge or
undercharge after a period ending twenty-four (24) Months from the end of the
Month in which the Refinery Product invoice or statement forming the basis of
the overcharge or undercharge was delivered or not delivered, as the case may
be, unless a claim for such adjustment shall have been presented prior to the
end of such period.  Any payment with respect to a retroactive adjustment shall
include an amount equal to interest on all amounts past due from the date of the
initial payment at the Base Rate, except in instances where neither Party knew
or could have known that the overcharge or undercharge occurred, in which case
interest shall run from the date of demand for payment.

     11.5 Either Party, upon notice in writing to the other, shall have the
right at reasonable hours to audit the accounts and records relating to the
accounting or billing under the provisions of any article hereof; provided,
however, that the auditing Party must take written exception to and make claim
upon the other Party for all discrepancies disclosed by said audit within
twenty-four (24) Months of the rendition of any statement or invoice forming the
basis of such claim.  Such audit shall be conducted by the auditing Party's
representative or auditor at the auditing Party's expense.

     11.6 All payments will be made without setoff or counterclaim; provided,
however, that upon a Party's (the defaulting Party) failure to make payment of
undisputed amounts on the due date, the other Party (the non-defaulting Party)
may, at its option and in its discretion, setoff 

                                      13

<PAGE>
 
against any amounts owed to the defaulting Party any amounts owed by the
defaulting Party under this Agreement or otherwise. The obligations of the non-
defaulting Party and the defaulting Party under this Agreement in respect of
such amounts shall be deemed satisfied and discharged to the extent of any such
setoff. The non-defaulting Party will give the defaulting Party notice of any
setoff made under this Section 11.6 as soon as practicable after the setoff is
made provided that failure to give such notice shall not offset the validity of
the setoff.

     11.7 ALL DISPUTES ARISING UNDER THIS ARTICLE XI THAT ARE NOT OTHERWISE
RESOLVED AS PROVIDED HEREIN SHALL BE SUBMITTED TO THE ALTERNATIVE DISPUTE
RESOLUTION PROCEDURES AS SET FORTH IN ARTICLE XIII HEREOF.  TO THE EXTENT THAT
ANY SUCH UNRESOLVED DISPUTE HAS NOT BEEN SUBMITTED TO SUCH ALTERNATIVE DISPUTE
RESOLUTION PROCEDURES WITHIN TWENTY-FIVE (25) MONTHS AFTER THE EVENT CAUSING THE
DISPUTE IS DISCOVERED OR REASONABLY SHOULD HAVE BEEN DISCOVERED, THE PARTY
ASSERTING THE CLAIM IN DISPUTE SHALL BE DEEMED TO HAVE WAIVED ANY SUCH CLAIM AND
ALL RIGHTS HEREUNDER WITH RESPECT THERETO.

                                  ARTICLE XII
                                 FORCE MAJEURE
                                 -------------

     12.1 In the event either Party is rendered unable, wholly or in part, by
Force Majeure to carry out its obligations under this Agreement, it is agreed
that upon such Party's giving notice and reasonably full particulars of such
Force Majeure in writing to the other Party after the occurrence of the cause
relied on, then the obligations of the Party giving such notice, so far as and
to the extent that they are affected by such Force Majeure, shall be suspended
during the continuance of any inability so caused, but for no longer period, and
such cause shall so far as possible be remedied with all reasonable dispatch.
This Agreement shall not be terminated by reason of any such cause, but shall
remain in full force and effect, and this Agreement shall not be extended
regardless of such curtailment or cessation.

     12.2 The term "Force Majeure" as used herein shall mean acts of God,
strikes, lockouts, or other industrial disturbances, acts of the public enemy,
wars, blockades, insurrections, riots, epidemics, landslides, lightning,
earthquakes, fires, tornadoes, hurricanes, or storms, tornado, hurricane, or
storm warnings which in any Parties' judgment require the precautionary shutdown
of the Refinery or any operating units thereof, or modes of transportation used
by WPC to transport Refinery Products, floods, washouts, arrests or restraints
of the government, either federal or state, civil or military, civil
disturbances, explosions, sabotage, breakage or accident to equipment, machinery
or lines of pipe, freezing of machinery, equipment or lines of pipe, electric
power shortages, inability of any Party to obtain necessary permits and/or
permissions due to existing or future rules, orders, laws or governmental
authorities (both federal, state and local), shutdowns of the Refinery or any
operating units thereof or modes of transportation used by WPC to transport
Refinery Products from the Refinery, due to explosion or other extraordinary
incident, or any other causes, whether of the kind herein enumerated or
otherwise, which were not reasonably foreseeable on 

                                      14
<PAGE>
 
the Effective Date, and which are not within the control of the Party claiming
suspension and which such Party is unable to overcome by the exercise of due
diligence. It is understood and agreed that the settlement of strikes or
lockouts shall be entirely within the discretion of the Party having the
difficulty, and that the above requirement that any Force Majeure shall be
remedied with all reasonable dispatch shall not require the settlement of
strikes or lockouts by acceding to the demands of opposing parties when such
course is inadvisable in the discretion of the Party having difficulty. The term
"Force Majeure" shall also include any event of Force Majeure occurring with
respect to the facilities or services of either CPC's or WPC's third Party
suppliers or customers delivering or receiving any product, fuel, feedstock, or
other substance necessary to the performance of such Party's obligations, and
shall also include curtailment or interruption of deliveries or service by such
third Party suppliers or customers as a result of an event of Force Majeure.

                                  ARTICLE XIII
                   ALTERNATIVE DISPUTE RESOLUTION PROCEDURES
                   -----------------------------------------

     13.1 Any dispute, controversy or claim arising out of or relating to this
Agreement, or the breach or performance hereof, including, but not limited to,
any disputes concerning the interpretation of the terms and provisions hereof,
shall be resolved through the use of the following procedures:

          (a)  The Parties will initially attempt in good faith to resolve any
               disputes, controversy or claim arising out of or relating to this
               Agreement.

          (b)  Should the Parties directly involved in any dispute, controversy
               or claim be unable to resolve same within a reasonable period of
               time, such dispute, controversy or claim shall be submitted to
               the senior executives of the Parties (the "Senior Executives")
               with such explanation or documentation as the Parties deem
               appropriate to aid the Senior Executives in their consideration
               of the issues presented.  The date the matter is first submitted
               to the Senior Executives shall be referred to as the "Submission
               Date."  The Senior Executives shall attempt in good faith,
               through the process of discussion and negotiation, to resolve any
               dispute, controversy, or claim presented to it within forty-five
               (45) Days after the Submission Date.

          (c)  If the Senior Executives cannot so resolve any dispute,
               controversy, or claim submitted to it within forty-five (45) Days
               after the Submission Date, the Parties shall attempt in good
               faith to settle the matter by submitting the dispute, controversy
               or claim to mediation within sixty (60) Days after the Submission
               Date using any mediator upon which they mutually agree.  If the
               Parties are unable to mutually agree upon a mediator within
               seventy-five (75) Days after the Submission Date, the case shall
               be referred for mediation to the office of Judicial Arbitration
               and Mediation Services, Inc. ("JAMS") in Houston, Texas. The cost
               of 

                                      15

<PAGE>
 
               the mediator will be split equally between the Parties unless
               they agree otherwise in writing.

          (d)  If the matter has not been resolved pursuant to the aforesaid
               mediation procedure within thirty (30) Days of the initiation of
               such procedure, or if either Party will not participate in such
               mediation, either Party may request that the matter be resolved
               through arbitration by submitting a written notice (the
               "Arbitration Notice") to the other.  Any arbitration that is
               conducted hereunder shall be governed by the Federal Arbitration
               Act, 9 U.S.C. (S) 1 et seq., and will not be governed by the
               arbitration acts, statutes, or rules of any other jurisdiction.

          (e)  The Arbitration Notice shall name the noticing Party's arbitrator
               and shall contain a statement of the issue(s) presented for
               arbitration.  Within fifteen (15) Days of receipt of an
               Arbitration Notice, the other Party shall name its arbitrator by
               written notice to the other and may designate any additional
               issue(s) for arbitration.  The two named arbitrators shall select
               the third arbitrator within fifteen (15) Days after the date on
               which the second arbitrator was named.  Should the two
               arbitrators fail to agree on the selection of the third
               arbitrator, either Party shall be entitled to request the Senior
               Judge of the United States District Court for the Southern
               District of Texas to select the third arbitrator.  All
               arbitrators shall be qualified by education or experience within
               the liquefied petroleum gas, natural gas liquids, or petroleum
               refining industry to decide the issues presented for arbitration.
               No arbitrator shall be:  a current or former director, officer,
               or employee of either Party or its Affiliates; an attorney (or
               member of a law firm) who has rendered legal services to either
               Party or its Affiliates within the preceding three Years; or an
               owner of any of the common stock of either Party, or its
               Affiliates.

          (f)  The three arbitrators shall commence the arbitration proceedings
               within twenty-five (25) Days following the appointment of the
               third arbitrator.  The arbitration proceedings shall be held at a
               mutually acceptable site and if the Parties are unable to agree
               on a site, the arbitrators shall select the site.  The
               arbitrators shall have the authority to establish rules and
               procedures governing the arbitration proceedings.  Each Party
               shall have the opportunity to present its evidence at the
               hearing.  The arbitrators may call for the submission of pre-
               hearing statements of position and legal authority, but no post-
               hearing briefs shall be submitted. The arbitration panel shall
               not have the authority to award (i) punitive or exemplary damages
               or (ii) consequential damages, except as expressly provided
               herein.  The arbitrators' decision must be rendered within thirty
               (30) Days following the conclusion of the hearing or submission
               of evidence, but no later than ninety (90) Days after appointment
               of the 

                                      16

<PAGE>
 
               third arbitrator. With respect to disputes regarding price or any
               redeterminations thereof under Article V, each Party shall submit
               to the arbitration panel a final offer of its proposed resolution
               of the dispute. A majority of the arbitrators shall approve the
               final offer of one Party without modification, and reject the
               offer of the other Party.

          (g)  The decision of the arbitrators or a majority of them, shall be
               in writing and shall be final and binding upon the Parties as to
               the issue(s) submitted.  The cost of the hearing shall be shared
               equally by the Parties, and each Party shall be responsible for
               its own expenses and those of its counsel or other
               representatives.  Each Party hereby irrevocably waives, to the
               fullest extent permitted by law, any objection it may have to the
               arbitrability of any such disputes, controversies or claims and
               further agrees that a final determination in any such arbitration
               proceeding shall be conclusive and binding upon each Party.
               Judgment on the award rendered by the arbitrator may be entered
               in any court having jurisdiction thereof.  The prevailing Party
               shall be entitled to recover reasonable attorneys' fees and court
               costs in any court proceeding relating to the enforcement or
               collection of any award or judgment rendered by the arbitration
               panel under this agreement.

          (h)  All deadlines specified herein may be extended by mutual written
               agreement of the Parties.  The procedures specified herein shall
               be the sole and exclusive procedures for the resolution of
               disputes between the parties arising out of or relating to this
               Agreement; provided, however, that a Party may seek a preliminary
               injunction or other preliminary judicial relief if in its
               judgment such action is necessary to avoid irreparable damage.
               Despite such action, the Parties will continue to participate in
               good faith in the procedures specified herein.  All applicable
               statutes of limitation, including, without limitation,
               contractual limitation periods provided for in this Agreement,
               shall be tolled while the procedures specified in this Section
               are pending.  The Parties will take all actions, if any,
               necessary to effectuate the tolling of any applicable statutes of
               limitation.

                                  ARTICLE XIV
                             LIMITATION OF DAMAGES
                             ---------------------
                                        
     14.1 FOR BREACH OF ANY PROVISION FOR WHICH AN EXPRESS REMEDY OR MEASURE OF
DAMAGES IS PROVIDED IN THIS AGREEMENT, SUCH EXPRESS REMEDY OR MEASURE OF DAMAGES
SHALL BE THE SOLE AND EXCLUSIVE REMEDY HEREUNDER, AND THE OBLIGOR'S LIABILITY
SHALL BE LIMITED AS SET FORTH IN SUCH PROVISION, AND ALL OTHER REMEDIES OR
DAMAGES ARE WAIVED.  IF NO REMEDY OR MEASURE OF DAMAGES IS EXPRESSLY PROVIDED
HEREIN, THE OBLIGOR'S LIABILITY 

                                      17

<PAGE>
 
SHALL BE LIMITED TO DIRECT ACTUAL DAMAGES ONLY, EXCLUDING LOST PROFITS, AND SUCH
DIRECT ACTUAL DAMAGES SHALL BE THE SOLE AND EXCLUSIVE REMEDY HEREUNDER, AND ALL
OTHER REMEDIES OR DAMAGES ARE WAIVED. IN NO EVENT SHALL EITHER PARTY BE LIABLE
TO THE OTHER PARTY UNDER ANY PROVISION OF THIS AGREEMENT (INCLUDING, WITHOUT
LIMITATION, ANY INDEMNITY PROVISION HEREOF) FOR PUNITIVE OR EXEMPLARY DAMAGES IN
TORT OR CONTRACT. EXCEPT AS EXPRESSLY PROVIDED HEREIN, NEITHER PARTY SHALL BE
LIABLE TO THE OTHER PARTY UNDER ANY PROVISION OF THIS AGREEMENT FOR
CONSEQUENTIAL, INCIDENTAL, OR INDIRECT DAMAGES. THE PRECEDING SENTENCE SHALL NOT
BE CONSTRUED AS LIMITING THE OBLIGATION OF EITHER PARTY HEREUNDER TO INDEMNIFY
THE OTHER PARTY AGAINST CLAIMS ASSERTED BY THIRD PARTIES, INCLUDING, BUT NOT
LIMITED TO, THIRD PARTY CLAIMS FOR CONSEQUENTIAL, INCIDENTAL, OR INDIRECT
DAMAGES, BUT EXCLUDING CLAIMS FOR SUCH DAMAGES UNDER ARTICLE IX. TO THE EXTENT
ANY PAYMENT REQUIRED TO BE MADE PURSUANT TO ANY PROVISION OF THIS AGREEMENT IS
AGREED BY THE PARTIES TO CONSTITUTE LIQUIDATED DAMAGES, THE PARTIES ACKNOWLEDGE
THAT THE DAMAGES ARE DIFFICULT OR IMPOSSIBLE TO DETERMINE, AND THAT SUCH PAYMENT
CONSTITUTES A REASONABLE APPROXIMATION OF THE AMOUNT OF SUCH DAMAGES.

                                   ARTICLE XV
                                 MISCELLANEOUS
                                 -------------

     15.1 This Agreement and the operations hereunder shall be subject to the
valid and applicable federal and state laws and the valid and applicable orders,
laws, local ordinances, rules, and regulations of any local, state or federal
authority having jurisdiction, but nothing contained herein shall be construed
as a waiver of any right to question or contest any such order, laws, rules, or
regulations in any forum having jurisdiction in the premises.  If any provision
of this Agreement is held to be illegal, invalid, or unenforceable under the
present or future laws effective during the term of this Agreement, (i) such
provision will be fully severable, (ii) this Agreement will be construed and
enforced as if such illegal, invalid, or unenforceable provision had never
comprised a part of this Agreement, and (iii) the remaining provisions of this
Agreement will remain in full force and effect and will not be affected by the
illegal, invalid, or unenforceable provision or by its severance from this
Agreement.  Furthermore, in lieu of such illegal, invalid, or unenforceable
provision, there will be added automatically as a part of this Agreement a
provision similar in terms to such illegal,  invalid, or unenforceable provision
as may be possible and as may be legal, valid, and enforceable.  If a provision
of this Agreement is or becomes illegal, invalid, or unenforceable in any
jurisdiction, the foregoing event shall not affect the validity or
enforceability in that jurisdiction of any other provision of this Agreement nor
the validity or enforceability in other jurisdictions of that or any other
provision of this Agreement.


                                      18
<PAGE>
 
     15.2 THIS AGREEMENT AND THE RIGHTS AND DUTIES OF THE PARTIES ARISING OUT OF
THIS AGREEMENT SHALL BE GOVERNED BY AND CONSTRUED,  ENFORCED, AND PERFORMED IN
ACCORDANCE WITH THE LAWS OF THE STATE OF TEXAS, AS THE SAME MAY BE AMENDED FROM
TIME TO TIME, WITHOUT GIVING EFFECT TO ANY CHOICE OR CONFLICT OF LAW PROVISION
OR RULE THAT WOULD CAUSE THE APPLICATION OF THE LAWS OF ANY JURISDICTION OTHER
THAN THE STATE OF TEXAS.

     15.3 This Agreement, including, without limitation, all exhibits hereto,
integrates the entire understanding between the Parties with respect to the
subject matter covered and supersedes all prior understandings, drafts,
discussions, or statements, whether oral or in writing, expressed or implied,
dealing with the same subject matter.  This Agreement may not be amended or
modified in any manner except by a written document signed by both Parties that
expressly amends this Agreement. No waiver by CPC or WPC of any of the
provisions of this Agreement shall be deemed or shall constitute a waiver of any
other provision hereof (whether or not similar) nor shall such waiver constitute
a continuing waiver unless expressly provided.  No waiver shall be effective
unless made in writing and signed by the Party to be charged with such wavier.

     15.4 The terms, covenants, and conditions of this Agreement shall inure to
and be binding upon the Parties and their respective successors and permitted
assigns, including, but not limited to, any and all subsequent owners of the
Refinery, but (i) neither Party may assign all or any part of its rights under
this Agreement without the prior written consent of the other Party, such
consent not to be unreasonably withheld, (ii) either Party may assign its rights
hereunder to any Affiliate of such Party without the approval of the other Party
(but such assignment shall in no way relieve or release the assigning Party from
any obligations hereunder, whether accrued or unaccrued, unless agreed to in
writing by the non assigning Party and (iii) either Party may, for collateral
purposes, mortgage, pledge, encumber, or grant a security interest in or a lien
on its interest in this Agreement and/or its rights hereunder to any commercial
bank, trustee, or other Person acting on behalf of any such commercial bank, but
only with the prior written consent of the other Party, such consent not to be
unreasonably withheld.  Any transfer or assignment in violation of this Section
15.4 shall be void.

     15.5 With the other documents required hereunder, CPC shall provide to WPC
a Material Safety Data Sheet for each Refinery Product delivered hereunder.  WPC
acknowledges that there may be hazards associated with the loading, unloading,
transporting, handling, or use of the Refinery Product sold hereunder, which may
require that warning be communicated to or other precautionary action taken with
all Persons handling, coming into contact with, or in any way concerned with the
Refinery Product sold hereunder.  WPC assumes as to its employees, independent
contractors, and subsequent purchasers of the Refinery Product sold hereunder
all responsibility for all such necessary warnings or other precautionary
measures relating to hazards to Person and property associated with the Refinery
Product and, furthermore, WPC shall defend at its own expense, indemnify fully
and hold harmless CPC and its parents, subsidiaries and Affiliates and its and
their agents, officers, directors, employees, representatives, successors and
assigns from and against any and all 

                                      19

<PAGE>
 
liabilities; losses; damages; demands; claims; penalties; fines; actions; suits;
legal, administrative or arbitration or alternative dispute resolution
proceedings; judgments, orders, directives, injunctions, decrees or awards of
any jurisdiction; costs and expenses (including, but not limited to, attorneys'
fees and related costs) arising out of or in any manner related to WPC's failure
to provide necessary warnings or other precautionary measures in connection with
the Refinery Product sold hereunder.

     15.6 Except as otherwise provided herein, each Party reserves to itself all
rights, set-offs, counterclaims, and other remedies and/or defenses which such
Party is or may be entitled to arising from or out of this Agreement or as
otherwise provided by law.

     15.7 (a)  Each Party agrees that it will maintain this Agreement, all
               terms and conditions of this Agreement, and all other
               Confidential Information (as hereinafter defined) in strictest
               confidence, and that it will not cause or permit disclosure of
               Confidential Information to any third Person without the express
               written consent of the other Party hereto.  Disclosures of
               Confidential Information otherwise prohibited by this Section
               15.7 may be made by either Party:  (i) to the extent necessary
               for such Party to enforce its rights hereunder against the other
               Party; (ii) to the extent a Party is contractually or legally
               bound to disclose information to a third Person (such as a
               shareholder or commercial lender);  (iii) only to the extent to
               which a Party hereto is required to disclose all or part of this
               Agreement by a statute or by the order of a court, agency, or
               other governmental body exercising jurisdiction over the subject
               matter hereof, by order, by regulations, or by other compulsory
               process (including, but not limited to, deposition, subpoena,
               interrogatory, or request for production of documents); (iv) to
               the extent required by the applicable regulations of a securities
               or commodities exchange; or (v) to an Affiliate (but only if such
               Affiliate agrees to be bound by the provisions of this Section).
               In addition to the foregoing, CPC may disclose the terms of this
               Agreement to any prospective purchaser of the Refinery.
               "Confidential Information" shall mean any information,
               proprietary to either Party and maintained by it in confidence or
               as a trade secret, including, without limitation, business plans
               and strategies, proprietary software, financial statements,
               customer or client lists, personnel records, analysis of general
               energy market conditions, sales, transportation, and service
               contracts and the commercial terms thereof, relationships with
               current and potential business partners, suppliers, customers,
               service providers and financial sources, data base contents and
               valuable information of a like nature relating to the business of
               such Party.  It is understood and agreed that Confidential
               Information shall not include information of a Party that (w)
               becomes generally available to the public at the time of
               disclosure to the other Party, or (x) after the time of
               disclosure to the other Party, was generally made available to
               the public without breach of this Agreement, 

                                      20

<PAGE>
 
               or (y) the Person receiving the information can show was
               rightfully in its possession at the time of disclosure, or (z)
               was rightfully acquired by the recipient from third Persons who
               did not themselves obtain such information under a
               confidentiality or other similar agreement with the Party whose
               information was disclosed.

          (b)  If either Party is or becomes aware of a fact, obligation, or
               circumstance that has resulted or may result in a disclosure of
               Confidential Information authorized by this Section 15.7, it
               shall so notify the other Party promptly and shall provide
               documentation or an explanation of such disclosure as soon as it
               is available.  Each Party further agrees to cooperate to the
               fullest extent in seeking confidential status to protect any
               Confidential Information so disclosed.

          (c)  The Parties hereto acknowledge that independent legal counsel,
               certified public accountants, or other consultants or independent
               contractors of a Party (collectively, "Outside Consultants") may,
               from time to time, be provided with a copy of this Agreement if,
               in the judgment of the disclosing Party, the information
               contained in this Agreement is necessary to the performance of
               such Outside Consultants' duties.  Accordingly, the Parties agree
               that such disclosure does not require consent by the other Party,
               provided that any such Outside Consultants agree to be bound by
               the provisions of this Section 15.7.

          (d)  Each Party will be deemed solely responsible and liable for the
               actions of its employees, Outside Consultants, officers, and
               agents for maintaining the confidentiality commitments of this
               Section 15.7, but will be required in that regard only to
               exercise such care in maintaining the confidentiality of the
               Confidential Information as such Party normally exercises in
               preserving the confidentiality of its other commercially
               sensitive information.

          15.8  Nothing contained in this Agreement shall be construed to create
an association, trust, partnership, or joint venture or impose a trust or
partnership duty, obligation, or liability on or with regard to either Party.

          15.9  In construing this Agreement, the following principles shall be
followed:

          (a)  no consideration shall be given to the fact or presumption that
               one Party had a greater or lesser hand in drafting this
               Agreement;

          (b)  examples shall not be construed to limit, expressly or by
               implication, the matter they illustrate;


                                      21
<PAGE>
 
          (c)  the word "includes" and its syntactical variants mean "includes,
               but is not limited to" and corresponding syntactical variant
               expressions; and

(d)  the plural shall be deemed to include the singular and vice versa, as
     applicable.

          15.10  EACH PARTY EXECUTING THIS AGREEMENT HEREBY WAIVES ITS
RESPECTIVE RIGHTS, IF ANY, UNDER THE DECEPTIVE TRADE PRACTICES-CONSUMER
PROTECTION ACT, SECTION 17.41 ET SEQ., TEXAS BUSINESS & COMMERCE CODE, A LAW
THAT GIVES CONSUMERS SPECIAL RIGHTS AND PROTECTIONS.  AFTER CONSULTATION WITH AN
ATTORNEY OF ITS OWN SELECTION, EACH PARTY EXECUTING THIS AGREEMENT VOLUNTARILY
CONSENTS TO THIS WAIVER.  IN ADDITION, EACH PARTY EXECUTING THIS AGREEMENT
HEREBY REPRESENTS AND WARRANTS TO THE OTHER PARTY THAT (I) SUCH PARTY'S LEGAL
COUNSEL WAS NOT DIRECTLY OR INDIRECTLY IDENTIFIED, SUGGESTED, OR SELECTED BY THE
OTHER PARTY OR BY AN AGENT OF SUCH OTHER PARTY, AND (II) NEITHER PARTY EXECUTING
THIS AGREEMENT IS IN A SIGNIFICANTLY DISPARATE BARGAINING POSITION.

          15.11  Any notice or other communication provided for in this
Agreement or any notice which either Party may desire to give to the other shall
be in writing and shall be deemed to have been properly given if and when sent
by facsimile transmission, delivered by hand; or, if sent by mail, upon deposit
in the United States mail, either U.S. Express Mail, registered mail, or
certified mail, with all postage fully prepaid; or, if sent by courier, by
delivery to a bonded courier with charges paid in accordance with the customary
arrangements established by such courier, in each case addressed to the parties
at the following addresses:

          If to WPC:    WARREN PETROLEUM COMPANY,
                        LIMITED PARTNERSHIP
                        13430 Northwest Freeway, Suite 1200
                        Houston, Texas  77040-6095
                        Attention:  Vice President and General Manager -
                        NGL Marketing
                        Phone: (713) 507-6408
                        Telecopy: (713) 507-3715

            with a copy to:

                        Vice President & General Counsel
                        WARREN PETROLEUM COMPANY,
                        LIMITED PARTNERSHIP
                        13430 Northwest Freeway
                        Suite 1200
                        Houston, Texas  77040-6095
                        Telephone: (713) 507-3725


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<PAGE>
 
                        Telecopy: (713) 507-6834

          If to CPC:    CHEVRON PRODUCTS COMPANY
                        91-480 Malakole Street,
                        Kapolei, Hawaii 96707-1807
                        Attention:  Refinery Manager
                        Telephone:  (808) 682-2215
                        Telecopy: (808) 682-2214

            with a copy to:

                        Vice President & General Counsel
                        CHEVRON PRODUCTS COMPANY
                        575 Market Street - Suite 2182
                        San Francisco, California 94105-2854
                        Telephone: (415) 894-3232
                        Telecopy: (415) 894-5489

or at such other address as either Party shall designate by written notice to
the other.  A notice sent by facsimile shall be deemed to have been received by
the close of the Business Day following the Day on which it was transmitted and
confirmed by transmission report or such earlier time as confirmed orally or in
writing by the receiving Party.  Notice by U. S. Mail, whether by U. S. Express
Mail, registered mail or certified mail, or by overnight courier shall be deemed
to have been received by the close of the second Business Day after the Day upon
which it was sent, or such earlier time as is confirmed orally or in writing by
the receiving Party.  Any Party may change its address or facsimile number by
giving notice of such change in accordance with herewith.

          15.12  No director, employee, or agent of either Party shall give or
receive any commission, fee, rebate, gift, or entertainment of significant cost
or value in connection with this Agreement.

          15.13  Each Party shall provide the other Party with such reports as
may be mutually agreeable to both Parties.  Each Party shall maintain such
records and accounts as may be necessary to the performance of its respective
duties and obligations hereunder, in accordance with good business practices.

          15.14  This Agreement is for the sole benefit of the Parties and their
respective successors and permitted assigns, and shall not inure to the benefit
of any other Person whomsoever, it being the intention of the Parties that no
third Person shall be deemed a third Party beneficiary of this Agreement.

          15.15  Each Party shall take such acts and execute and deliver such
documents in form and substance reasonably satisfactory to each of them, in
order to effectuate the purposes of this Agreement.


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          IN WITNESS WHEREOF, the parties hereto have executed this Agreement
the Day and Year first above written.


 
                                        WARREN PETROLEUM COMPANY,
                                        LIMITED PARTNERSHIP
                                        BY: WARREN PETROLEUM G.P., INC.
                                    
                                    
                                        By:  _____________________________
                                        Name: _____________________________
                                        Title:  _____________________________
                                    
                                    
                                    
                                    
                                    
                                        CHEVRON PRODUCTS COMPANY,
                                        a division of CHEVRON U.S.A. INC.
                                    
                                    
                                        By: _______________________________
                                        Name: _____________________________
                                        Title:  _____________________________

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