<Page>

                                                              Exhibit 10.18

"Pages where confidential treatment has been requested are marked 'Confidential
Treatment Requested.' The redacted material has been separately filed with the
Commission, and the appropriate section has been marked at the appropriate
place and in the margin with a star (*)."

                             FRACTIONATION AGREEMENT

                                 by and between

                         CEDAR BAYOU FRACTIONATORS, L.P.

                                       and

                   WILLIAMS ENERGY MARKETING & TRADING COMPANY
                            EFFECTIVE OCTOBER 1, 1999



<Page>



<Table>
<Caption>
                                                                       Page
                                                                       ----
<S>           <C>                                                      <C>
ARTICLE I:    DEFINITIONS ..............................................1

ARTICLE II:   TERM .....................................................4

ARTICLE III:  WILLIAMS PERFORMANCE .....................................4

ARTICLE IV:   CBF'S PERFORMANCE.........................................6

ARTICLE V:    TRANSFER OF CUSTODY ......................................7

ARTICLE VI:   MEASUREMENT ..............................................8

ARTICLE VII:  COMPENSATION TO CBF ......................................8

ARTICLE VIII: STORAGE SERVICES ........................................10

ARTICLE IX:   FUEL AND ELECTRICITY SUPPLY OPTIONS .....................13

ARTICLE X:    TAXES AND OTHER PAYMENTS ................................14

ARTICLE XI:   ACCOUNTING AND AUDIT PROCEDURES .........................14

ARTICLE XII:  BILLING AND PAYMENT .....................................15

ARTICLE XIII: FORCE MAJEURE ...........................................16

ARTICLE XIV:  INDEMNIFICATION AND LIMITATION OF LIABILITY .............17

ARTICLE XV:   MISCELLANEOUS ...........................................19

EXHIBIT "A" - WILLIAMS' DEDICATED PLANTS

EXHIBIT "B" - SPECIFICATIONS FOR SPECIFICATION PRODUCTS

EXHIBIT "C" - STORAGE OF SPECIFICATION PRODUCTS
</Table>

<Page>



                             FRACTIONATION AGREEMENT

         THIS AGREEMENT (the "Agreement") is made and entered into as of the
3rd day of December, 1998, but effective as of September 1, 1999, by and
between. Cedar Bayou Fractionators. L.P., a Delaware limited partnership
(hereinafter referred to as "CBF"), and Williams Energy Marketing & Trading
Company, a Delaware corporation (hereinafter referred to as "Williams"),
sometimes also referred to individually as "Party" and collectively as
"Parties."

         WITNESSETH:

         WHEREAS, Williams owns, controls or has rights to certain volumes of
natural gas liquids recovered by various natural gas processing facilities
available for fractionation; and

         WHEREAS, CBF owns a Fractionation Facility, hereinafter defined,
Situated In Mont Belvieu, Chambers County, Texas; and

         WHEREAS, CBF has the right to store Specification Products
(hereinafter defined) in the Storage Facility (hereinafter defined) owned and
operated by Dynegy Midstream Services, Limited Partnership ("Dynegy"), and
situated in Mont Belvieu, Chambers County, Texas; and

         WHEREAS, Williams has arranged for the transportation and delivery
of its owned and/or controlled Raw Product (hereinafter defined) to CBF at
the Storage Facility in Mont Belvieu, Texas; and

         WHEREAS, CBF has arranged for the receipt of such Raw Product from
Williams, as well as Raw Product owned by third parties, at the Delivery
Point (hereinafter defined) for fractionation in the Fractionation Facility;
and

         WHEREAS, it is the mutual desire of CBF and Williams that CBF
receive Williams' Raw Product at the Delivery Point and redeliver to
Williams, or its designee, Specification Products, (hereinafter defined), at
the Storage Facility or at other Mutually agreeable locations.

         NOW THEREFORE, in consideration of the premises and the mutual
covenants and agreements herein contained, the parties hereto agree as
follows:

                             ARTICLE 1: DEFINITIONS

         When the following terms or expressions are used in this Agreement,
they shall have the meanings defined below:

         "AFFILIATE" means, of any Person, a Person Controlling, Controlled by
         or under common Control with, directly or indirectly, through one or
         more intermediaries, such Person. Any

                                        1

<Page>

         Person Shall be deemed to be an Affiliate of any specified Person if
         such Person owns 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 or if fifty percent (50%) or more of the voting
         securities of the specified Person and such Person are under common
         Control.

         "BARREL" shall mean 42 Gallons.

         "BASE RATE" shall mean a per annum rate of interest equal to the lower
         of (i) the maximum rate of interest allowed by law or (ii) two percent
         above the "prime rate" of interest as announced from time to time by
         the First National Bank of Chicago.

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

         "CLAIMS" shall have the meaning as ascribed to it in Section 13
         hereinafter.

         "COMPONENT" shall mean the individual hydrocarbon constituents of Raw
         Product, including but not limited to: methane, ethane, propane,
         isobutane, normal butane, isopentane, normal pentane, hexanes and
         heavier, as well as other non-hydrocarbon components authorized
         hereunder.

         "CONTROL" of a non-natural Person means the power, directly or
         indirectly, to (i) elect, appoint or cause the election or appointment
         of at least a majority of the members of the board of directors of such
         Person (or if such Person is a non-corporate Person, Persons having
         similar powers), or (ii) direct or cause the direction of the
         management and policies of such Person, in either case through
         beneficial ownership of the capital stock (or similar ownership
         interests) of such Person or otherwise.

         "DAY" OR "DAILY" shall mean a twenty-four (24) hour period commencing
         7:00 a.m. Central Standard or Daylight Savings time, as applicable, and
         extending until 7:00 a.m. Central Standard or Daylight Savings time, as
         applicable, on the following Day.

         "DELIVERY POINT" shall mean the custody transfer meter of the Pipeline
         utilized to deliver Raw Product to CBF hereunder which is located near
         the Storage Facility.

         "DYNEGY" shall have the meaning ascribed to it in the recitals.

         "FORCE MAJEURE" shall have the meaning ascribed to it in Section 12.2.

                                        2

<Page>

         "FRACTIONATION FACILITY" OR "FRACTIONATOR" shall mean the fractionation
         unit owned by CBF situated in Mont Belvieu, Chambers County, Texas,
         which is operated by Dynegy and which is used for the purpose of
         fractionating Raw Product streams into Specification Products.

         "FRACTIONATION VOLUME RESERVATION" shall mean the maximum amount of
         fractionation capacity in the Fractionator that is reserved to
         fractionate Williams' Raw Product which initially shall be 35,000 BPD,
         and thereafter, may change in accordance with Section 4.2 hereinafter.

         "GALLON" shall mean one U.S. liquid Gallon. which is the unit of
         volume used for the purpose of measurement of liquid. One U.S. liquid
         Gallon contains 231 cubic inches when the liquid is at a temperature of
         60 degrees Fahrenheit and at the vapor pressure of the liquid being
         measured.

         "MONTH" OR "MONTHLY" shall mean the period commencing on the first Day
         of a Month and ending on the last Day of such Month.

         "OPERATOR" shall mean Dynegy Midstream Services, Limited Partnership.

         "PERSON" means any individual, corporation, partnership, limited
         partnership, limited liability partnership, limited liability company
         (whether domestic or foreign), joint venture, association, joint-stock
         company, trust, estate, custodian, trustee, executor, administrator,
         nominee, entity in a representative capacity, unincorporated,
         organization, or governmental agency or authority.

         "PIPELINE(S)" shall mean any pipeline which delivers Williams' Raw
         Product to CBF as provided in this Agreement. Currently, the six
         pipelines capable of delivering Raw Product to CBF hereunder are the
         Seminole Pipeline, the Chaparral Pipeline, the West Texas Pipeline, the
         Mobil Pipeline, Dynegy's 12" NGL pipeline from Lake Charles, and the
         Black Lake Pipeline.

         "PRIMARY TERM" shall have the meaning as ascribed to it in Article II.

         "RAW PRODUCT" shall mean that mixture of natural gas liquid
         hydrocarbons meeting the specifications established by the Pipeline(s)
         as of December 1, 1998.

         "REDELIVERY POINT" shall mean the point at which William's
         Specification Products enter into the Storage Facility.

         "SPECIFICATION PRODUCT(S)" shall mean the liquid hydrocarbons meeting
         the specifications provided for in Exhibit "B", attached hereto,
         fractionated from the Raw Product.

                                        3

<Page>

                         'Confidential Treatment Requested'


         "STORAGE FACILITY" shall mean the underground storage facilities owned
         and operated by Dynegy at Mont Belvieu, Chambers County, Texas,
         including, but not limited to, Specification Product storage caverns
         and all related surface and subsurface equipment.

         "YEAR" OR "YEARLY" shall mean a period of 365 consecutive Days;
         provided, however that any Year which contains the date of February 29
         shall consist of 366 consecutive Days.

                                ARTICLE II: TERM

2.1      This Agreement shall have a primary term commencing effective October
*        1, 1999, and ending [REDACTED] (the "Primary Term"), and shall
         continue in effect from Year to Year thereafter; provided that either
         Party shall have the right to terminate this Agreement effective at the
         end of the Primary Term or any Yearly anniversary thereafter by giving
         the other Party at least ninety (90) Days prior written notice of its
         election to terminate this Agreement.

                       ARTICLE III: WILLIAMS' PERFORMANCE

3.1      Except as set forth in Section 3.2 and subject to the other terms of
         this Agreement, Williams hereby commits for fractionation hereunder and
         shall deliver or cause to be delivered to the Delivery Point the Raw
         Product which it owns and/or controls and which is delivered to the
         Pipeline(s) from the sources listed in Exhibit "A". Williams further
         agrees that if at any time beginning January 1, 2000, and at any time
*        thereafter, it has delivered less than [REDACTED] of the Fractionation
         Volume Reservation based on the Daily average volume for the preceding
         ninety (90) Days, then it will commit for fractionation hereunder and
         will deliver or cause to be delivered to the Delivery Point during such
         time period as necessary to enable Williams to meet the Fractionation
         Volume Reservation, additional uncommitted volumes of Raw Product
         which Williams owns or controls, if any, or may in the future have
         available from sources that are not listed in Exhibit "A" and which
         are delivered to any of the Mont Belvieu Fractionators (as defined
         hereinafter). For the purpose of this Section 3.1, the term "Mont
         Belvieu Fractionators" shall include all fractionation facilities
         situated in or near Mont Belvieu, Texas, and the fractionation
         facilities currently owned by Phillips Petroleum situated in Sweeney,
         Texas, and by Mobil situated in Beaumont, Texas.


3.2      The following volumes of Raw Product shall be excepted from the
         commitment set forth in Section 3.1 above.

         (a)      Raw Product produced from the gas plants listed in Exhibit "A"
                  and sold and delivered to local markets near such gas plants.

         (b)      Raw Product produced from the Kutz and Lybrook gas plants
                  which is currently or in the future may be dedicated to Amoco
                  pursuant to agreements between Williams or its Affiliates and
                  Amoco (the "Amoco Dedication"). Upon

                                        4

<Page>

                  termination and/or expiration of such Amoco Dedication, the
                  volumes of Raw Product produced from the Kutz and Lybrook gas
                  plants shall be subject to the committment set forth in
                  Section 3.1 above unless and/or until such Raw Product is
                  subsequently dedicated to Amoco.

         (c)      Any volumes in excess of the Fractionation Volume Reservation
                  which CBF has elected not to accept pursuant to Section 4.1.
                  CBF agrees to notify Williams as to its election whether it
                  will accept such excess volumes within fifteen (15) days
                  of its receipt of notification from Williams as to the
                  availability of such excess volumes.

         (d)      Any volumes dedicated for fractionation in the Fractionator in
                  accordance with that certain "Option to Acquire Interest in
                  Cedar Bayou Fractionators, L.P." dated of even date herewith
                  between Williams Field Services Company and Dynegy Midstream
                  Services, Limited Partnership.

3.3      Williams shall direct Pipeline to prepare and furnish to CBF and CBF
         shall prepare or cause to be prepared during each Month, an allocation
         of ownership of the Pipeline's commingled Raw Product, by Components
         actually delivered to CBF. Williams and CBF shall accept and rely on
         such allocation, unless contested as described in Section 11.4.

3.4      Prior to the beginning of each Month, CBF will estimate the volumes of
         Specification Products for which disposition instructions will be
         required from Williams. Subject to Section 4.3 below, such estimates
         will be established by utilizing the actual volumes of Raw Product
         delivered to the Fractionation Facility during the most recent Month
         for which actual volumes are available and adjusting for anticipated
         variances as may be advised by Williams from time to time. As set forth
         in Article X of this Agreement, CBF shall reconcile Monthly statements
         detailing Williams' Specification Product movement no later than the
         last Day of each succeeding Month following the Month in question.

3.5      Williams acknowledges that it is procuring the fractionation services
         under this Agreement for the purpose of fractionating the Raw Product
         set forth in Section 3.1 and not for the purpose of reselling such
         fractionation services and agrees not to resell such services on a
         stand-alone basis. Reselling of said fractionation services shall mean
         Williams' transactions involving the purchase or exchange of Raw
         Product for fractionation at the Fractionator with the intent of
         profiting on such purchase or exchange/fractionation transactions
         based in whole or in substantial part on the difference between the
         fractionation fee defined or implied in such third party purchase or
         exchange agreement and the fractionation fee charged to Williams under
         this Agreement. Notwithstanding anything in this Section 3.5 to the
         contrary, Williams may include fractionation service under this
         Agreement in combination with other services which rely extensively on
         the Mid-America Pipeline System, the Seminole Pipeline or the West
         Texas LPG Pipeline.

                                        5

<Page>

                       'Confidential Treatment Requested'


                          ARTICLE IV: CBF'S PERFORMANCE

4.1      CBF shall accept delivery of and provide fractionation for a maximum
         volume of Raw Product committed by Williams hereunder equal to the
         Fractionation Volume Reservation. The intial Fractionation Volume
         Reservation shall be 35,000 Barrels per Day as determined on a Monthly
         Daily average basis. Volumes above the Fractionation Volume Reservation
         will be accepted by CBF for fractionation on a space available basis.


4.2      Williams may increase the Fractionation Volume Reservation set forth in
*        Section 4.1 in increments of [REDACTED] Barrels per Day up to a maximum
*        of [REDACTED] Barrels per Day by giving at least ninety (90) Days prior
         written notice to CBF of its election to increase same. It is
         understood and agreed that (i) there Must be at least ninety (90) Days
         between successive notification dates and (ii) the Fractionation Volume
         Reservation may only be exercised once during each ninety (90) Day
         Period. Subsequent to January 1, 2000, Dynegy may decrease the
*        Fractionation Volume Reservation to [REDACTED] of the Daily average
         volume of Raw Product deliveries from Williams at the Delivery Point
         for the preceding 90 days (excluding deliveries during the Month of
         September, 1999) if (i) the Sources listed in Exhibit "A" have operated
         at expected capacity in full ethane recovery mode for the preceding 90
         days and (ii) the Daily average volume of Raw Product deliveries from
         Williams at the Delivery Point for the preceding 90 days is less than
*        [REDACTED] of the Fractionation Volume Reservation.

4.3      Notwithstanding anything in this Agreement to the contrary, during each
         Month that Williams delivers Raw Product at the Delivery Point, CBF
         shall re-deliver Specification Products ratably during that Month to
         Williams (or its designee) at the Redelivery Point or at other
         mutually-agreed locations. For purposes of this provision, CBF will
         deem that the total volume of Williams Raw Product which has been
         nominated for delivery at the Delivery Point during a Month has
         actually been delivered ratably throughout that Month so long as at
*        least [REDACTED] of such Williams-nominated volume has actually been
         delivered at the Delivery Point before the twenty-first (21st) day of
         that Month. If the Raw Product Volumes delivered by Williams by the
         twenty-first (21st) day of such Month are less than the volumes of
         Raw Product nominated by Williams for delivery during such Month, with
         the result that there is an imbalance between the volume of Williams'
         Raw Product deliveries at the Delivery Point and CBF's deliveries of
         Specification Products to Williams (determined in accordance with
         Section 4.5 below), CBF shall make ratable returns of Specification
*        Products to Williams in the ratio of [[REDACTED] Specification Products
*        to Williams] to [[REDACTED] of the Raw Products delivered by Williams
         during the remainder of that Month and in the immediately succeeding
         Months, as necessary] until any such imbalance is eliminated.

4.4      CBF shall not hold back Specification Products from Williams as a
         minimum inventory requirement. However, CBF shall have the right to
         allocate the distribution of Specification Products due Williams and
         other customers during normal scheduled CBF


                                       6
<Page>

         fractionation plant turn-arounds which shall not exceed a total of
         seven (7) Days per Year. The foregoing shall not apply during periods
         of force majeure, as defined hereinafter.

4.5      The quantity of the five (5) Specification Products due Williams will
         be as follows, based on the Pipelines' reported volumes of each
         Component which have been delivered for Williams' account:

         (1)      E/P MIX (80/20): the volume will be equal to (a) 100% of the
                  ethane Component plus methane Component up to 1.5 liquid
                  volume percent of the ethane Component, (b) plus
                  propane Component equal to 25% of the volume in (a) above.

         (2)      PROPANE: the volume will be equal to 100% of the propane
                  Component minus the propane included in the EP Mix.

         (3)      ISOBUTANE: the volume will be equal to 100% of the
                  isobutane Component.

         (4)      NORMAL BUTANE: the volume will be equal to 100% of the normal
                  butane Component.

         (5)      NATURAL GASOLINE: the volume will be equal to 100% of the
                  isopentane and heavier Components.

                         ARTICLE V: TRANSFER OF CUSTODY

5.1      Williams warrants that it has the right to cause the Raw Product to be
         fractionated hereunder. Custody of the Raw Product shall transfer to
         CBF at the Delivery Point, subject to Williams' right to receive
         allocated volumes of Specification Products as provided in Section 4.3
         above. Subject to the foregoing, custody of Specification Products
         shall be delivered to Williams or its designee at the points more
         particularly described in Section 8.1(2) hereinafter.

5.2      It is understood and agreed that (i) title to the Raw Product and the
         Specification Product(s) recovered therefrom and stored hereunder
         pursuant to the provisions of Article VIII hereof shall remain in
         Williams, subject to being commingled with like Raw Product and
         Specification Product(s) in CBF's and/or Dynegy's custody, , which
         Williams hereby grants unto CBF the right to do so, and (ii)
         Specification Product(s) redelivered to Williams by CBF will be
         redelivered from such commingled pool of Specification Products. With
         respect to the Specification Product(s) stored hereunder pursuant to
         the provisions of Article VIII hereof, it is specifically agreed as
         follows:

         (a)      In the event there should be any loss of Specification
                  Product(s) from the Storage Facility, excluding normal
                  operating losses, and such loss is not attributable to the


                                       7
<Page>

                       'Confidential Treatment Requested'


                  failure of CBF or its agent or representative to exercise that
                  degree of care as would be exercised by a reasonably careful
                  Person under like circumstances, then Williams shall be
                  prorated a portion of the remaining product by Dynegy on the
                  basis of the ratio of Williams' stored Specification
                  Product(s) to the total volumes of like stored
                  Specification Product(s) in such Facility, including, without
                  limitation, those volumes owned by Williams, CBF and Dynegy.

         (b)      In the event there should be a loss of William's Specification
                  Products excluding normal operating losses, and it is
                  ultimately determined that such loss was attributable to CBF's
                  or its agent's or representative's failure to exercise that
                  degree of care as would be exercised by a reasonably careful
                  Person under like circumstances, then, it is agreed that CBF
                  shall have the option, in its sole discretion, to replace
                  Williams' lost volumes as soon as reasonably possible with
                  like Specification Product(s) or to pay Williams the
                  replacement value of such lost specification Product(s) at the
                  time of the loss based on the Monthly average of the daily
                  high and low prices for such Specification Products as quoted
                  by OPIS for Mont Belvieu during the Month in which such loss
                  occured.

                             ARTICLE VI: MEASUREMENT

6.1      Volumes of Raw Product delivered at the Delivery Point shall be
         measured and calculated in accordance with the delivering Pipeline
         measurement procedures in effect for the Delivery Point.

6.2      Volumes of Specification Products delivered by CBF to Williams in
         accordance with Article IV, shall be measured and calculated in
         accordance with CBF's standard measurement procedures at Mont Belvieu
         which shall conform to good measurement practices in the industry and
         the then Current API Manual of Petroleum Measurement Standards

                        ARTICLE VII: COMPENSATION TO CBF

7.1      Subject to Article VIII, as full consideration for the fractionation
         services provided hereunder, Williams shall pay to CBF a fractionation
         fee ("Fractionation Fee") for each Gallon of Raw Product delivered at
         the Delivery Point by, or on behalf of, Williams to CBF each Month.
         Effective October 1, 1999 through December 31, 1999, the Fractionation
*        Fee shall be fixed at [REDACTED] per Gallon. Beginning January 1, 2000,
         the Fractionation Fee shall be determined on a calendar quarter basis
         by the following formulas determined as of the first Day of such
         calendar quarter:

*       Fractionation Fee = [REDACTED]

         Where:


                                       8
<Page>

                             'Confidential Treatment Requested'


                  Fractionation Fee = the fee charged for fractionation
                           during such calendar quarter.

                  Fuel  =  The fuel cost (in $/MMBtu) equivalent to the average
                           Houston Ship Channel Index of INSIDE FERC'S GAS
                           MARKET REPORT for natural gas (large packages) for
                           the proceding calendar quarter.

                  Elec  =  The combined average actual cost of purchased
                           electricity (In CENTS/KWH) at the Fractionator for
                           the preceding calendar quarter.

                  CPIU  =  Consumer Price Index. All Urban Consumers --
                           ("CPI-U"), U.S. city average, All items, for the last
                           Month of the preceding calendar quarter, as published
                           by the United States Bureau of Labor Statistics (the
                           "BLS") or any successor agency thereto (the "CPI-U
                           Index"). The CPI-U Index shall be taken from the data
                           published by the BLS, as of the date hereof,
                           electronically at the following Internet address:
                           ftp://ftp.bls.gov/pub/special.requests/cpi/cpiai.txt,
                           or at any successor Internet address or as same is
                           published in hardcopy form.

7.2      During any calendar quarter in which Williams has elected to provide
         Fuel pursuant to Article VIII, the Fractionation Fee shall be computed
         the same as in Section 7.1, except that the value of "Fuel" in the
         formula shall be zero (0).

7.3      During any calendar quarter in which Williams has elected to provide
         electrical power pursuant to Article VIII, the Fractionation Fee shall
         be computed the same as in Section 7.1, except that the value of
         "Elec" in the formula shall be zero (0).

7.4      CBF will provide Williams an E/P Mix as described in Section 4.6 but
         will insure Williams will not suffer devaluation of its ethane product
         in the market by virtue of such ethane being delivered as E/P Mix
         instead of purity ethane. Each calendar Month, a differential value
         between purity ethane and E/P Mix shall be calculated by comparing (i)
*        [REDACTED] as quoted by the Oil Price Information Service for Mont
*        Belvieu during that Month to (ii), [REDACTED] as quoted by OPIS for
         Mont Belvieu during that Month.

         If the amount in (ii) above is greater than the amount in (i) above,
*        then [REDACTED] Subject to the limitations set forth hereinafter, if
         the amount in (i) above is greater than the amount in (ii) above,
*        then [REDACTED] Williams shall not be required to


                                       9
<Page>

         pay to CBF a larger cumulative amount under this Section 7.4 than
         the cumulative amount paid by CBF to Williams. If at the time the
         calculation set forth in this Section 7.4 reflects that the amount in
         (i) above is greater than the amount in (ii) above and if the
         cumulative amount paid by CBF to Williams under this Section 7.4
         is less than or equal to the cumulative amount paid by Williams to
         CBF, then the amount that would otherwise be payable by Williams to CBF
         shall instead be accrued by CBF as a credit against future amounts
         payable by CBF to Williams under this Section 7.4.

                         ARTICLE VIII: STORAGE SERVICES

8.1      In connection with the fractionation services to he provided by CBF to
         Williams as provided herein, subject to the following terms and
         provisions. CBF shall store Williams' Specification Products in the
         Storage Facility owned and operated by Dynergy:

         (1)      PRODUCT STORAGE. For and in consideration of the fees to be
                  paid by Williams to CBF as provided herein, CBF hereby agrees
                  to store up to, but not to exceed, the maximum quantity of
                  Specification Products set forth in Exhibit "C" which is
                  attached hereto and made a part hereof (the "Storage Volume").

         (2)      PRODUCT REDELIVERY. Specification Product(s) redelivered to
                  Williams out of the Storage Facility will only be made on the
                  request of Williams' designated representative or duty
                  authorized agent. CBF will not recognize sales, assignments
                  or transfers of title to Specification Product(s) while in
                  storage unless made in a manner approved by CBF and Dynegy
                  in advance and then only to another person or entity that has
                  entered into a valid storage agreement with Dynegy.
                  Specification Product(s) redelivered by CBF hereunder shall be
                  redelivered into any common carrier pipeline currently
                  connected to Dynegy's terminal facilities adjacent to its
                  underground storage Facilities ("Dynegy's Terminal").
                  CBF's redelivery of Specification Product(s) to Williams shall
                  be subject to operating conditions, rates of delivery,
                  delivery pressures, scheduling, etc. of the pipeline in which
                  Williams requests Specification Product(s) be delivered into
                  (the "Receiving Pipeline"). Custody of the Specification
                  Product(s) redelivered hereunder shall be deemed to be
                  transferred at the point where the Specification Product(s)
                  enters into the Receiving Pipeline and is measured. Williams
                  shall use its best efforts to give CBF reasonable notice of
                  withdrawals of Specification Product(s). Redelivery of
                  Specification Products shall always be subject to the physical
                  capabilities of Dynegy's Storage Facilities and Terminal.
                  Measurement of Specification Product(s) redelivered hereunder
                  shall take place as near to the points of redelivery as
                  practicable to CBF and shall be made by CBF in accordance with
                  Dynegy's standard measurement procedures which shall conform
                  to good measurement practices in the industry. All
                  measurements made by or on behalf of CBF shall be binding on
                  the parties hereto unless proven to be in error. Williams
                  shall have the right to witness all such measurements. Tank
                  cars and trucks will be handled on a first in first out
                  basis.


                                      10
<Page>


         (3)      CERTIFICATION OF EQUIPMENT. If in the future Dynegy allows
                  redelivery of Specification Product(s) by tank cars and/or
                  trucks, Williams agrees that all tank cars and trucks used
                  to make withdrawals at the Dynegy Terminal shall meet or
                  exceed all federal, state and municipal safety, operating
                  and insurance requirements and further agrees to certify
                  same to CBF and Dynegy and provide copies of all government
                  approvals to it before the tank cars and trucks will be
                  accepted at Dynegy's Terminal and/or Facilities.

         (4)      STENCHING. CBF will odorize or cause to be odorized all
                  shipments of propane out of storage by tank car or truck
                  in accordance with standard industry practice (currently
                  1.5 pounds ethyl mercaptan per 10,000 Gallons), or as
                  required by governmental agencies having proper
                  jurisdiction, and will odorize shipments of other
                  Specification Product(s) if requested in writing by
                  Williams to do so. Williams agrees to pay CBF for providing
                  this odorization service the fees set forth in Exhibit "C".
                  Williams accepts all responsibility for improper amounts of
                  malodorant subsequent to shipment, the dissipation of
                  malodorant and, where CBF and/or Dynegy provides
                  documentation of the odorization required by this
                  Agreement. Williams agrees to defend, indemnify and hold
                  CBF and Dynegy and its parents, subsidiaries and Affiliates
                  and its and their agents, officers, directors, employees,
                  representatives, successors and assigns harmless from any
                  and all 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
                  attorney's fees and any cost or expense of incident
                  investigation) or any liability arising from any claims of
                  whatever kind due to injuries or damages which occur after
                  delivery to Williams and arise in connection with Williams'
                  or its customer's or their customer's transportation,
                  storage, use, handling, or resale of Specification
                  Product(s) covered hereunder. This indemnification
                  obligation includes among any other claims, those
                  comprising lack of or inadequate warning materials,
                  improper amounts, use or type of odorant, "odorant fading,"
                  lack of warning on supplemental warning systems (such as
                  gas detectors) and improper training or monitoring of
                  Williams', its customer's and/or their customer's warning
                  and/or training programs. Williams' indemnity obligation
                  shall be applicable even if such damages are determined to
                  have been partly caused by the fault of CBF and/or Dynegy
                  or if liability without fault is imposed on CBF and/or
                  Dynegy, the only exception to such obligation being
                  where the fault of CBF and/or Dynegy is determined to be
                  the sole cause of such damages.

         (5)      STORAGE AND HANDLING CHARGES.


                                      11

<Page>

                  (a)      Williams shall pay CBF Monthly the rates, fees and
                           charges set forth in Exhibit "C", including, but
                           not limited to, the Receipt Fee. Throughput Charges
                           and Redelivery Fees, as applicable.

                  (b)      If at the end of any Month the total volume of all
                           Specification Products stored by Williams,
                           excluding undelivered volumes of Specification
                           Product(s) for which timely distribution
                           instructions have been given, exceeds the Storage
                           Volume, Williams shall pay to CBF the Excess
                           Storage fee as set forth in Exhibit "C". Williams
                           agrees to use all reasonable efforts to prevent
                           volumes of Specification Products stored hereunder
                           from exceeding the Storage Volume at any time during
                           each Month.

                  (c)      If at the expiration or termination of this
                           Agreement Williams continues to have Specification
                           Product(s) in storage (which the parties expressly
                           do not contemplate and CBF in no way condones)
                           which was delivered into storage under the terms
                           of this Agreement and for which timely
                           distribution instructions have not been given,
                           then Williams shall pay to CBF the Excess Storage
                           fee as set forth in Exhibit "C" each Month
                           thereafter based on the highest balance of all
                           Specification Products held in storage at any time
                           during such Month. CBF's acceptance of funds
                           pursuant to this Section shall in no way be
                           construed as a renewal of this Agreement, PROVIDED,
                           HOWEVER, Williams shall continue to be bound by all
                           terms and conditions of this Agreement as long as
                           any of Williams' Specification Product(s) remains
                           in storage.

                  (d)      In addition to the provisions of (c) above, in the
                           event Williams fails to remove its Specification
                           Product(s) at the expiration of the term of this
                           Agreement, CBF shall have the right to sell all or
                           any portion of such Specification Product(s) at
                           Mont Belvieu OPIS prices and on terms as CBF, in
                           its sole discretion, deems appropriate under the
                           then existing circumstances. If CBF sells all or a
                           portion of Williams' Specification Product(s)
                           under the terms of this Section 5(d), within
                           thirty (30) Days of its receipt of the proceeds
                           derived from the sale of such Specification
                           Product(s), CBF shall remit same to Williams less
                           (i) all of CBF's reasonable costs and expenses
                           associated with any such sale(s), (ii) a sales
                           commission equal to five percent (5%) of the
                           gross proceeds of such sale(s), and (iii) any fees
                           then due and owed by Williams to CBF.

         (6)      LIEN FOR UNPAID CHARGES. Williams hereby grants unto CBF a
                  lien against any Specification Product(s) of Williams
                  remaining in storage at any time for any overdue amounts
                  which may be owing by Williams to CBF hereunder which are
                  not disputed in writing by Williams in accordance with the
                  provisions of Section 12.1 hereof. CBF specifically
                  reserves the right to refuse to redeliver Specification

                                      12

<Page>

                       'Confidential Treatment Requested'

                  Product(s) stored by Williams at any time that there
                  remains any overdue undisputed amounts due and owing by
                  Williams to CBF according to the terms hereof. Without
                  prejudice to any other remedies that CBF may have at law,
                  in equity and/or pursuant to the terms and provisions
                  hereof. Dynegy may enforce the lien granted herein by
                  public or private sale of any or all of Williams'
                  Specification Product(s) remaining in storage and at any
                  time or place and at Mont Belvieu OPIS prices after giving
                  Williams not less than fifteen (15) Days notice of such
                  sale.

                 ARTICLE IX: FUEL AND ELECTRICITY SUPPLY OPTIONS

9.1      Williams may, on a calendar quarter basis, elect to supply the
         volume of fuel gas required to fractionate its Raw Product by giving
         CBF thirty (30) Days prior written notice of such election ("Fuel
         Gas Supply Option").

9.2      If Williams elects to exercise its Fuel Gas Supply Option, Williams
*        shall supply to CBF, at Mont Belvieu, [REDACTED] Btus of fuel gas for
         each Gallon of Raw Product delivered to CBF by Williams hereunder.

9.3      For each Month in which Williams elects to exercise its Fuel Gas
         Supply Option, an estimated fuel supply requirement will be
         determined by multiplying the estimated number of Gallons that
*        Williams will deliver to CBF during said Month by [REDACTED] Btu's
         per Gallon. CBF shall maintain an imbalance account to keep track of
         under and over deliveries of fuel gas by Williams. The Month-end
         balance in such imbalance account shall be cleared by (1) a cash
         payment to CBF by Williams if Williams has, in the aggregate,
         under-delivered fuel gas relative to its actual fuel gas requirements
         for such Month or (2) a cash payment to Williams by CBF if Williams
         has, in the aggregate, over-delivered fuel gas relative to its actual
         fuel gas requirements for such Month. Such payment shall be calculated
         by multiplying the total quantity of such imbalance times the Houston
         Ship Channel Index for large packages (in $/MMBtu) for such Month as
         published in INSIDE F.E.R.C.'S GAS MARKET REPORT.

9.4      If, and to the extent that, CBF incurs any transportation charges or
         penalties from any natural gas transporter as a result of over- or
         under-deliveries by Williams of fuel gas to such transporter
         relative to Williams's estimate of its fuel gas requirements for
         such Month, CBF shall bill Williams for such charges or penalties on
         CBF's Monthly bill under Article XII, and Williams shall pay such
         amount as specified therein.

9.5      Williams reserves the right to elect to supply CBF the amount of
         electrical power required to fractionate its Raw Product by giving
         CBF thirty (30) Days' prior written notice of such election
         ("Electricity Supply Option"); provided, however, such Electricity
         Supply Option shall only become available and be implemented through
         mutually

                                      13

<Page>

                       'Confidential Treatment Requested'

         agreeable procedures negotiated in good faith by the Parties after
         there is an industry mechanism in place to allow for same.

9.6      If Williams elects to exercise its Electricity Supply Option,
*        Williams shall supply to CBF, at Mont Belvieu, [REDACTED] of a
         Kilowatt-hour (KWH) of electricity for each Gallon of Raw Product
         delivered to CBF by Williams hereunder.

                       ARTICLE X: TAXES AND OTHER PAYMENTS

10.1     Williams shall be responsible for the payment of any royalties
         overriding royalties, and other similar payments due or to become
         due on the Raw Products or the Specification Products which are
         subject to this Agreement. Any tax applicable to the
         production, ownership or transfer of the Raw Products or the
         Specification Products or the services provided by CBF hereunder,
         including but not limited to any tax applicable to stored volumes of
         Specification Products, shall be borne and paid by Williams unless
         such tax is by law imposed upon CBF, in which event, such tax shall
         be paid by CBF and reimbursed by Williams upon receipt of invoice
         for same. Williams shall indemnify and hold CBF and their respective
         Affiliate's directors, officers, agents and employees harmless from
         and against any and all claims, demands or causes of action of any
         kind, together with all loss, damage and expense (including court
         costs and attorney's fees) arising with respect to the payment of
         any taxes, royalties, overriding royalties and other payments due or
         to become due on the services, Raw Products or Specification
         Products which are subject to this agreement.

                      ARTICLE XI: ACCOUNTING AND AUDIT PROCEDURES

11.1     Williams or its designee shall furnish the following reports to CBF:
         (i) Williams' share of Components in the Raw Product delivered each
         Month for the Month in question by the tenth (10) Day of the next
         succeeding Month; (ii) instructions for delivery of Specification
         Products for the Month in question during the Month in question, as
         set forth in Section 3.4; and (iii) twelve (12) Month forecast of
         Raw Product projected to be delivered under this Agreement, as
         requested by CBF from time to time.

11.2     CBF shall furnish each Month for the preceding Month, the following
         reports to Williams: (i) volumes of Williams' Specification Products
         attributable to the Raw Product delivered to CBF each Month, in
         accordance with the reconciliation described in Section 3.4; (ii)
         volumes of Specification Products delivered to Williams or its
         designee each Month in accordance with the reconciliation described
         in Section 3.4; and (iii) Williams' inventories of Specification
         Product(s) each Month, in accordance with the reconciliation
         described in Section 3.4. CBF shall furnish initial reports of these
         items by the twentieth (20) Day of the Month succeeding, the Month
         and shall fully complete volume and money reconciliations as
         described in Section 11.3 below.

                                      14

<Page>

11.3     Volume and money reconciliation shall be prepared by CBF on a
         Monthly basis. Williams and CBF shall cooperate to identify and
         reconcile volume balances and amounts owed. As CBF completes each
         Month's reconciliation, a copy of the reconciliation shall be sent
         to Williams but no later than the last Day of the Month succeeding
         the Month in question. The intent of the parties is that any
         imbalances between volumes of Raw Product delivered at the Delivery
         Point by  Williams and volumes of Specification Products delivered by
         CBF to  Williams at the Redelivery Point (as any such imbalances are
         determined in accordance with Section 4.5) shall be resolved on a
         volumetric basis as set forth in Section 4.3. No monetary resolution
         of any such imbalance shall be effective unless both parties have
         agreed, in writing, thereto.

11.4     All invoices or statements issued by CBF and any volume and money
         reconciliation reports, or balancing reports, during any calendar
         Year shall conclusively be presumed to be true and correct after
         twenty-four (24) Months following the end of any such calendar
         Year, unless within the said twenty-four (24) Month period the other
         Party takes written exception thereto and makes claim on the Party
         issuing the invoice, statement or report for adjustment.

11.5     Williams, upon at least thirty (30) Days prior written notice to
         CBF, shall have the right to audit CBF's records pertaining to
         performance under this Agreement, for any calendar Year within the
         twenty-four (24) Month period following the end of such calendar
         Year; provided, however, the making of an audit shall not extend
         the time for the taking of written exception to and the adjustments
         provided for in Section 11.4. Williams shall make every reasonable
         effort to conduct an audit in a manner which will result in a
         minimum of inconvenience to CBF. CBF shall reply in writing to an
         audit report within ninety (90) Days after receipt of such report.

11.6     CBF shall retain all financial and volume records for a minimum of
         thirty-six (36) Months following the end of any calendar Year.

                        ARTICLE XII: BILLING AND PAYMENT

12.1     After receiving allocation information from Pipeline at mid-Month
         and again at the end of each Month, CBF shall furnish to Williams an
         invoice reflecting all applicable fees and charges due under this
         Agreement and Williams shall pay to CBF via electronic funds
         transfer the amounts due no later than ten (10) Days after Williams'
         receipt of invoice. If the Day on which any payment is due is not a
         Business Day, then the relevant payment shall be due upon the
         immediately succeeding Business Day. Any amounts which remain due
         and owing after the due date shall bear interest thereon at the Base
         Rate. If a good faith dispute arises as to the amount payable in any
         statement, the amount not in dispute shall be paid. If Williams
         elects to withhold any payment otherwise due as a consequence of a
         good faith dispute, Williams shall provide CBF with written notice
         of its reasons for withholding payment and, if the amount of such
         invoice is equal to or greater than ten thousand dollars ($10,000)
         or the total aggregate amount of all invoices

                                      15

<Page>

         in which Williams has withheld payment and is outstanding at any
         time is greater than or equal to fifty thousand dollars ($50,000).
         Williams shall simultaneously place the disputed amount into an
         escrow account at a mutually acceptable commercial bank, pending
         resolution of the dispute. Williams' election to withhold payment
         from CBF and escrow same as provided herein shall be exercised
         within thirty (30) Days from Williams' receipt of the invoice giving
         rise to such good faith dispute, otherwise, Williams' right to
         withhold payment and escrow same as provided herein shall terminate.
         If it is subsequently determined, whether by mutual agreement of the
         Parties or otherwise, that (i) Williams is required to pay all or
         any portion of the disputed amounts to CBF or (ii) Williams is
         entitled to reimbursement for an invoice it paid, in addition to
         paying such amounts, the Party making such payment also shall pay
         interest accrued on such amounts at the Base Rate from (1) the
         original due date until paid in full, if Williams is required to pay,
         or (2) the date Williams paid the disputed invoice, until paid in
         full, if CBF is required to pay.

                           ARTICLE XIII: FORCE MAJEURE

13.1     In the event either Party hereto is rendered unable, wholly or in
         part, by reason of Force Majeure to carry out its obligations under
         this Agreement, 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
         such Party, other than the obligation to pay money due hereunder,
         insofar and only insofar as 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 reasonably
         possible, be remedied with all reasonable dispatch.

13.2     The term "Force Majeure" shall mean any causes, whether the kind
         enumerated herein or otherwise, which are not within the control of
         the Party claiming suspension and which by the exercise of due
         diligence such Party is unable to prevent or overcome and may
         include acts of God, strikes, lockouts or other industrial disputes
         or disturbances, acts of the public enemy, wars, blockades,
         insurrections, riots, epidemics, landslides, lightning, earthquakes,
         fires, tornadoes, hurricanes, storms, and warnings for any of the
         foregoing which may necessitate the precautionary shut-down of
         wells, plants, pipelines, gathering systems, loading facilities,
         terminals, the Fractionator or any portion thereof, or other related
         facilities, floods, washouts, arrests and restraints of governments
         (either federal, state, civil or military), civil disturbances,
         explosions, sabotage, breakage or accidents to equipment, machinery,
         plants, the Fractionator or any portion thereof, or lines of pipe,
         the lack or failure of brine or brine handling capacity, the making
         of repairs or alterations to any of the foregoing, inability to
         secure labor or materials, partial or entire failure of wells or gas
         supply, electric power shortages or outages, necessity for
         compliance with any court order, or any law, statute, ordinance,
         rule, regulation or order promulgated by a governmental authority
         having or asserting jurisdiction, inclement weather that
         necessitates extraordinary measures and expense to construct
         facilities and/or maintain operations. Such term shall likewise
         include, in those instances where either Party hereto

                                      16

<Page>

         is required to obtain servitudes, rights-of-way, grants, permits or
         licenses to enable such Party to fulfill its obligations hereunder,
         the inability of such Party to acquire, or delays on the part of
         such Party in acquiring, at a reasonable cost and after the
         exercise of reasonable diligence, such servitudes, rights-of-way
         grants, permits or licenses, and in those instances where either
         Party hereto is required to furnish materials and supplies for the
         purpose of constructing or maintaining facilities to enable such
         Party to fulfill its obligations hereunder, the inability of such
         Party to acquire, or delays on the part of such Party in acquiring,
         at reasonable cost and after the exercise of reasonable diligence,
         such materials and supplies. The term "Force Majeure" shall also
         include any event of force majeure occurring with respect to the
         facilities or services of either Party's suppliers or customers
         providing a service or providing any equipment, goods, supplies or
         other items necessary to the performance of such Party's
         obligations, and shall also include curtailment or interruption of
         deliveries or services by such third-party suppliers or customers as
         a result of an event defined as Force Majeure hereunder.

13.3     Notwithstanding Section 12.1 above, 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 the opposing Party when such
         course is inadvisable in the discretion of the Party having the
         difficulty.

13.4     During any period of force majeure claimed by CBF, Williams shall
         have the right to make alternative arrangements for the
         fractionation of Raw Product dedicated to CBF provided that, by so
         doing, Williams shall not prejudice Williams' rights and obligations
         after termination of such force majeure to resume fractionating such
         Raw Product hereunder and shall not relieve CBF  of any rights and
         obligations to provide fractionation hereunder.

                ARTICLE XIV: INDEMNIFICATION AND LIMITATION OF LIABILITY

14.1.    WILLIAMS' INDEMNITIES: REGARDLESS OF THE PRESENCE OR ABSENCE OF ANY
         INSURANCE COVERAGE MAINTAINED BY EITHER PARTY HERETO, WILLIAMS
         HEREBY RELEASES, AND AGREES TO DEFEND, PROTECT, INDEMNIFY AND HOLD
         HARMLESS, CBF, ITS OPERATOR, PARTNERS AND ITS PARTNERS' AFFILIATES
         AND THOSE ENTITIES' RESPECTIVE DIRECTORS, OFFICERS, EMPLOYEES,
         AGENTS AND REPRESENTATIVES ("CBF PARTIES") FROM AND AGAINST ANY AND
         ALL CLAIMS, DEMANDS, CAUSES OF ACTION, LIABILITY, LOSS, DAMAGE,
         PENALTIES, FINES, COST AND EXPENSE, INCLUDING COURT COSTS AND
         REASONABLE ATTORNEY'S FEES IN CONNECTION THEREWITH ("CLAIMS"),
         ARISING OUT OF OR RELATED TO:

                                      17

<Page>



         (1)      DESTRUCTION, LOSS OR CONTAMINATION OF WILLIAMS' RAW PRODUCT
                  AND SPECIFICATION PRODUCTS ARISING FROM ANY CAUSE OTHER THAN
                  DYNEGY'S FAILURE TO EXERCISE THAT DEGREE OF CARE AS WOULD BE
                  EXERCISED BY A REASONABLY CAREFUL PERSON UNDER LIKE
                  CIRCUMSTANCES: and

         (2)      Any Claims arising from injuries or damages to persons or
                  properties arising from damages to the tangible physical
                  property in connection with Williams', or its contractors,
                  handling and possession of Williams' Raw Product or
                  Specifications Products prior to delivery of same to CBF and
                  after delivery of same from CBF back to Williams or its
                  designated representative to the extent of Williams' or its
                  contractor's negligence or legal fault for same.


14.2     CBF INDEMNITIES: REGARDLESS OF THE PRESENCE OR ABSENCE OF ANY INSURANCE
         COVERAGE MAINTAINED BY EITHER PARTY HERETO, CBF HEREBY RELEASES, AND
         AGREES TO DEFEND, PROTECT, INDEMNIFY AND HOLD HARMLESS, WILLIAMS, AND
         ITS AFFILIATES, AND AGENTS AND THOSE ENTITIES' RESPECTIVE DIRECTORS,
         OFFICERS, EMPLOYEES, AGENTS AND REPRESENTATIVES ("WILLIAMS PARTIES")
         FROM AND AGAINST ANY AND ALL CLAIMS, DEMANDS, CAUSES OF ACTION,
         LIABILITY, LOSS, DAMAGE, PENALTIES, FINES, COST AND EXPENSE, INCLUDING,
         WITHOUT LIMITATION, ENVIRONMENTAL AND INCLUDING COURT COSTS AND
         REASONABLE ATTORNEY'S FEES IN CONNECTION THEREWITH ("CLAIMS"), ARISING
         FROM:

         (1)      INJURIES (INCLUDING DEATH) OR DAMAGES TO PERSONS (INCLUDING,
                  WITHOUT LIMITATION, THE WILLIAMS PARTIES) OR PROPERTY ARISING
                  FROM OR IN CONNECTION WITH CBF'S, OR ITS CONTRACTORS',
                  HANDLING AND POSSESSION OF WILLIAMS' RAW PRODUCT OR
                  SPECIFICATION PRODUCTS WHILE SAME ARE IN CBF'S POSSESSION AND
                  PRIOR TO DELIVERY OF SAME TO WILLIAMS AT THE STORAGE FACILITY
                  TO THE EXTENT OF CBF'S OR ITS CONTRACTOR'S NEGLIGENCE OR LEGAL
                  FAULT FOR SAME; and

         (2)      DESTRUCTION, LOSS OR CONTAMINATION OF WILLIAMS' RAW PRODUCT OR
                  SPECIFICATION PRODUCTS ARISING FROM DYNEGY'S FAILURE TO
                  EXERCISE THAT DEGREE OF CARE AS WOULD BE EXERCISED BY A
                  REASONABLE CAREFUL PERSON UNDER LIKE CIRCUMSTANCES.

14.3     LIMITATION OF LIABILITY:

         (a)      EXCEPT AS TO THIRD PARTY CLAIMS COVERED BY THE INDEMNITY
                  PROVISIONS OF SECTIONS 13.1 AND 13.2, NEITHER CBF, CBF'S
                  OPERATOR NOR WILLIAMS SHALL BE


                                      18
<Page>



                  RESPONSIBLE OR LIABLE TO THE OTHER, OR TO THEIR AGENTS, FOR
                  ANY SPECIAL, INCIDENTAL, CONSEQUENTIAL OR PUNITIVE DAMAGES
                  ARISING OUT OF THIS AGREEMENT OR ANY BREACH HEREOF, REGARDLESS
                  OF THE CAUSES OF SAME, INCLUDING ANY SITUATION WHERE SUCH
                  DAMAGES ARE CAUSED BY THE NEGLIGENCE OR FAULT OF THE PARTY
                  WHOSE LIABILITY IS LIMITED HEREBY.

         (b)      NOTWITHSTANDING ANYTHING TO CONTRARY SET FORTH IN THIS
                  AGREEMENT, , CBF SHALL NOT BE RESPONSIBLE FOR ANY LOSSES,
                  INJURIES OR DAMAGES HEREUNDER, HOWEVER CAUSED, INCLUDING,
                  WITHOUT LIMITATION, LOSSES, INJURIES OR DAMAGES COVERED UNDER
                  THE INDEMNITY PROVISIONS SET FORTH ABOVE, IN EXCESS OF THE
                  FEES AND RATES PAID BY WILLIAMS TO CBF AS PROVIDED HEREIN
                  DURING THE EIGHTEEN MONTHS IMMEDIATELY PRECEDING THE DATE ON
                  WHICH SUCH LOSS, INJURY OR DAMAGE OCCURRED.

14.4     NOTICE OF CLAIM AND FILING OF SUIT. Claims by Williams and all other
         Persons claiming, by, through or under Williams with respect to the
         Specification Product stored in the Storage Facility, must be presented
         in writing to CBF within a reasonable time, and in no event later than
         sixty (60) Days after (i) Williams' Specification Product(s) is
         redelivered or removed from the Storage Facility or (ii) Williams is
         notified by Dynegy that loss of or injury to the Specification
         Product(s) has occurred, whichever is shorter. No action may be
         maintained by Williams and any other Persons claiming by, through or
         under Williams, against CBF for loss of or injury to Specification
         Product(s) stored in the Storage Facility unless a written claim
         therefor is received by CBF within the time periods set forth herein
         and such action is commenced within nine (9) Months after (a) Williams'
         Specification Product(s) is redelivered or removed from the Storage
         Facility or (b) Williams is notified by CBF that loss of or injury to
         Specification Product(s) has occurred, whichever is shorter. In the
         situation where CBF notifies Williams of a loss or injury to
         Specification Product(s), the time limits for making written claims and
         the maintaining of actions after notice, as set forth herein, begin on
         the date such notice is sent by CBF.

                            ARTICLE XV: MISCELLANEOUS

15.1     EXISTING LAWS AND REGULATIONS. This Agreement and the operations
         hereunder shall be subject to the applicable federal and state laws and
         the applicable orders, laws, rules and regulations of any state or
         federal authority having or asserting jurisdiction, but nothing
         contained herein shall be construed as a waiver of any right to
         question or contest any such order, law, rule or regulation. The
         parties shall be entitled to regard all such laws, rules, regulations
         and orders as valid and may act in accordance therewith until such time
         as the same may be invalidated by final judgment in a court of
         competent jurisdiction.

15.2     GOVERNING LAW. 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



<Page>



         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     WAIVER. No waiver by either Party of any default under this Agreement
         or any of the provisions of this Agreement shall be deemed to be a
         waiver of any future default or any other provision hereof, whether of
         a like or a different character. No waiver shall be effective unless
         made in writing and signed by the Party to be charged with such waiver,
         nor shall waiver constitute a continuing waiver unless expressly
         provided by the Party to be charged with such waiver.

15.4     SUCCESSORS AND ASSIGNS. This Agreement shall inure to the benefit of
         and be binding upon the parties hereto and their respective successors
         and assigns. Notwithstanding the foregoing, neither Party may assign
         this Agreement, nor any interest herein, without the prior written
         consent of the other Party, which consent shall not be unreasonably
         withheld or delayed; provided, however, that a Party may from time to
         time (i) designate an Affiliate to perform this Agreement, either in
         whole or in part, such performance being considered that of the Party
         hereto, or (ii) assign this agreement to an Affiliate without obtaining
         the other Party's consent thereto. It is understood, however, that by
         such designation or assignment, said Party hereto does not thereby
         avoid obligations imposed by the terms and provisions hereof, past
         present or future. Williams further specifically agrees that it will
         not assign its interest in the volumes of Raw Product dedicated to this
         Agreement without the prior written consent of CBF, which consent
         shall not be unreasonably withheld; provided such assignment is made
         subject to this Agreement and any Assignee ratifies and adopts this
         Agreement in writing.

15.5     EXHIBITS. Unless specifically otherwise provided, if any term or
         condition expressed or implied in any Exhibit to this Agreement
         conflicts or is at variance with any term or condition of this
         Agreement, this Agreement shall prevail. All Exhibits as referenced
         herein are attached hereto and made a part hereof.

15.6     DTPA WAIVER. THE PARTIES CERTIFY THAT THEY ARE NOT "CONSUMERS" WITHIN
         THE MEANING OF THE TEXAS DECEPTIVE TRADE PRACTICES-CONSUMER PROTECTION
         ACT, SUBCHAPTER E OF CHAPTER 17, SECTIONS 17.42, ET SEQ., OF THE TEXAS
         BUSINESS AND COMMERCE CODE, AS AMENDED ("DTPA"). THE PARTIES COVENANT,
         FOR THEMSELVES AND FOR AND ON BEHALF OF ANY SUCCESSOR OR ASSIGNEE,
         THAT, IF THE DTPA IS APPLICABLE, (a) THE PARTIES ARE "BUSINESS
         CONSUMERS" AS THAT TERM IS DEFINED IN THE DTPA, (b) OTHER THAN SECTION
         17.555 OF THE TEXAS BUSINESS AND COMMERCE CODE, EACH PARTY HEREBY
         WAIVES AND RELEASES ALL OF ITS RIGHTS AND REMEDIES UNDER THE DTPA AS
         APPLICABLE TO THE OTHER PARTY AND ITS SUCCESSORS AND ASSIGNS, AND (c)
         EACH PARTY SHALL DEFEND AND INDEMNIFY THE OTHER FROM AND AGAINST ANY
         AND ALL CLAIMS OF OR BY THAT PARTY OR ANY OF ITS SUCCESSORS AND ASSIGNS
         OR ANY OF ITS OR THEIR AFFILIATES BASED IN WHOLE OR IN



<Page>



         PART ON THE DTPA, ARISING OUT OF OR IN CONNECTION WITH THE TRANSACTION
         SET FORTH IN THIS AGREEMENT.

15.7     HEADINGS, ARTICLES AND SECTIONS. All references to "Articles" and
         "Sections" herein pertain to Articles and Sections of this Agreement,
         unless expressly Stated otherwise. Headings are for purposes of
         reference only and shall not be used to construe the meaning of this
         Agreement.

15.8     PRINCIPLES OF CONSTRUCTION AND INTERPRETATION. In construing this
         Agreement, the following principles shall be followed:

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

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

         (iii)    the word "includes" and its syntactical variants mean
                  "includes, but is not limited to" and corresponding
                  syntactical variant expressions: and

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

15.9     NOTICES. Any notice, request, instruction, correspondence, or other
         documentation to be given hereunder by either Party to the other shall
         be in writing and delivered personally or mailed by registered or
         certified mail, postage prepaid and return receipt requested, or
         facsimile as follows:

         FOR CBF:

             To:               Cedar Bayou Fractionators, L.P.
                               c/o Dynegy Midstream Services, Limited
                               Partnership
             Attention:        Vice President, Asset Marketing and Services
             At:               1000 Louisiana, Suite 5800
                               Houston, Texas 77002-5050
             Phone:            (713) 507-3843
             FAX:              (713) 767-8286



                                       21
<Page>



            With a copy to:     Vice President and General Counsel
                                Dynegy Midstream Services, Limited Partnership
                                1000 Louisiana, Suite 5800
                                Houston, TX 77002-5050
                                Phone: 713-507-3725
                                Fax:   713-507-6987

         FOR WILLIAMS (EXCEPT ACCOUNTING MATTERS):

            To:                 Williams Energy Marketing & Trading Company
            Attention:          Vice President, Energy Marketing and Trading
            At:                 One Williams Center
                                Tulsa, Oklahoma 74172
            Phone:              (918) 573-8525

            With a copy to:     Williams Energy Marketing & Trading Company
            Attention:          Director of Margins Management
            At:                 1800 S. Baltimore Avenue
                                P.O. Box 645
                                Tulsa, Oklahoma 74101-0645
            Phone:              (918) 599-3771
            FAX                 (918) 581-1495

         FOR WILLIAMS ACCOUNTING MATTERS:

            To:                 Williams Energy Marketing & Trading Company
            Attention:          Senior Distribution Representative
            At:                 One Williams Center
                                Tulsa, Oklahoma 74172
            Phone:              (918) 573-2919

         A notice sent by facsimile shall be deemed to have been receive by the
         close of the first 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 its 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.

15.10    NO THIRD PARTY BENEFICIARY. 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



                                       22
<Page>



         be deemed a third party beneficiary of this Agreement or otherwise have
         any rights hereunder.

15.11    SEVERABILITY. 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, 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.

15.12    ENTIRE AGREEMENT AND AMENDMENT. 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.

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

15.14    NO PARTNERSHIP OR ASSOCIATION. 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.

15.15    NO COMMISSIONS, FEES OR REBATES. Except as expressly authorized by this
         Agreement, 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. Any
         representative or representative(s) authorized by either Party may
         audit the applicable records of the other Party for the purpose of
         determining whether there has been compliance with this Section.

15.16    WILLIAMS' OPTION TO TERMINATE EARLY. If by the close of business
         February 15, 1999, Williams and Dynegy have not reached a mutually
         agreeable accord on one or more of the Ancillary Deals identified in
         the Letter Agreement dated July 13, 1998, between



                                      23
<Page>



         Dynegy and Williams, then Williams shall have the right during the
         succeeding thirty (30) Day period to terminate this Agreement
         effective as April 1, 2000. If Williams' elects to exercise this
         termination option, the fractionation fee described in Section 7.1
         shall be changed to 1.88 cents per Gallon. To exercise this option,
         Williams must provide written notification of its election to
         terminate this Agreement early to the other party prior to March 1,
         1999.

15.17    DYNEGY BOARD OF DIRECTORS APPROVAL. Notwithstanding the execution of
         this Agreement by representatives of CBF as set forth below, it is
         understood and agreed that this Agreement is being entered into by the
         Parties hereto in connection with other Agreements entered into or to
         be entered into by one or more of the parties hereto and others,
         including, but not limited to, an Option Agreement between CBF and an
         affiliate of Williams, an Option Agreement between an affiliate of
         Williams and Dynegy, and a Storage Agreement between CBF and Seminole
         Pipeline Company (collectively, the "Related Agreements"), all of
         which, including this Agreement, are subject to the approval by the
         senior management of Dynegy and/or the Board of Directors of Dynegy's
         ultimate parent, Dynegy, Inc. It is understood and agreed that if the
         senior management of Dynegy and the Board of Directors of Dynegy,
         Inc., if required, fails to approve all of the Related Agreements, and
         this Agreement by December 31, 1998, then, upon written notification by
         Dynegy, this Agreement shall become null and void.

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


CEDAR BAYOU FRACTIONATORS, L.P.
By:    DYNEGY MIDSTREAM SERVICES,
       LIMITED PARTNERSHIP, Operator
By:    DYNEGY MIDSTREAM G. P., INC., ITS General Partner

By:    /s/ Stephen A. Furbacher
     ------------------------------
Title:  PRESIDENT
       ----------------------------


WILLIAMS ENERGY MARKETING & TRADING COMPANY

By:    /s/ Steven Malcolm
     ------------------------------
Title:   President and CEO
        ---------------------------


                                      24
<Page>



                                   EXHIBIT "A"
                                       to
                             Fractionation Agreement
                                 by and between
                         Cedar Bayou Fractionators, L.P.
                                       and
                   Williams Energy Marketing & Trading Company

                           WILLIAMS' DEDICATED PLANTS

<Table>
<Caption>

GAS PLANTS                     LOCATION
----------                     --------
<S>                            <C>
Echo Springs                   Carbon County, Wyoming

Ignacio                        La Plata County, Colorado

Kutz                           San Juan County, New Mexico

Lybrook                        Rio Arriba County, New Mexico

Opal                           Lincoln County, Wyoming

Lisbon                         San Juan County, Utah
</Table>

OTHER SOURCES:

Any other injection points along the Mid America Pipeline System or the
Seminole Pipeline in which Raw Product owned and/or controlled by Williams is
injected and which is to be transported to and fractionated at Mont Belvieu,
Texas.

                                      25
<Page>



                                   EXHIBIT "B"
                                       to
                             Fractionation Agreement
                                 by and between
                        Cedar Bayou Fractionators, L. P.
                                       and
                  Williams Energy Marketing & Trading Company

                                  ETHANE-PROPANE
                                  80-20 MIXTURE
                                  SPECIFICATION

Product characteristics with test methods are herein specified for
ethane-propane 80-20 mixtures received by Cedar Bayou Fractionators, L.P..

<Table>
<Caption>
                                                                                           TEST METHODS
PRODUCT CHARACTERISTICS                             MINIMUM           MAXIMUM              LATEST REVISION
-----------------------                             -------           -------              ---------------
<S>      <C>                                        <C>               <C>                  <C>
1.       COMPOSITION                                                                       ASTM E-260
         Percent by Liquid Volume
         Methane (Percent of Ethane)                                  2.0                  GPA 2177
         Ethylene (Percent of Ethane)                                 1.0
         Methane, Ethane & Ethylene                 78.0              82.0
         Propane, Propylene, & Butanes              18.0              22.0                 ASTM D-2163
         Propylene                                                    1.0
         Butanes                                                      0.8

2.       CORROSION
         Copper Strip @ 100 DEG. F                                    1-b                  ASTM D-1838
         (Invalid if additive or inhibitor
         is used.)
         Corrosion Additive or Inhibitor.
         PPM by Weight                                                1                    Applicable           Industry
                                                                                           Practices

3.       TOTAL SULFUR
         PPM by Weight in Liquid                                      120                  ASTM D-3246

4.       DRYNESS                                                      No Free Water        Visual

5.       CARBON DIOXIDE
         PPM by Weight in Liquid                                      1.000                GPA 2177
</Table>

PRODUCT ACCOUNTING

For accounting purposes, methane and ethylene shall be considered ethane,
propylene and butanes shall be considered propane within the above listed
specification limits.

Any excess of these hydrocarbon Components above the specification limits
shall not be accounted for.

                                       1
<Page>

                              PROPANE SPECIFICATION

Product characteristics with test methods are herein specified for propane
received by Cedar Bayou Fractionators, L.P.. This product meets the
requirement of the GPA HD-5 propane specification.

<Table>
<Caption>

                                                                                                     TEST METHODS LATEST
PRODUCT CHARACTERISTICS             MINIMUM                            MAXIMUM                       REVISION
-----------------------             -------                            -------                       -------------------
<S>                                 <C>                                <C>                           <C>
1. COMPOSITION                                                                                       ASTM E-260
   Percent by Liquid Volume Ethane                                     As limited by
                                                                       other Components
                                                                       & vapor pressure.
   Propane                          90.0                               100
   Propylene                                                           5.0                           ASTM D-2163
   Butanes & Heavier                                                   2.5

2. VAPOR PRESSURE
   Psig @ 100 DEG. F                                                   208                           ASTM D-1267

3. CORROSION
   Copper Strip @ 100 DEG. F                                           1-b                           ASTM D-1838
   (Invalid if additive or
     inhibitor is used.)
   Corrosion Additive or
     Inhibitor. PPM by Weight.                                         1                             Applicable Industry Practices

4. TOTAL SULFUR
   PPM by Weight in Liquid                                             120                           ASTM D-3246

5. HYDROGEN SULFIDE
   PPM by Weight in Liquid                                             1                             Field - Length of Stain Tube
   (Lab test required if field                                                                       Lab Chromatography with Flame
     test is positive.)                                                                              Photometric Detector


6. CARBONYL SULFIDE
   PPM by Weight in Liquid                                             2                             Field - Length of Stain Tube
   (Field test invalid if C(4) +
     exceeds 1.0 LV%)
   (Lab test required if                                                                             Lab - UOP 212 or UOP 791
     field test is positive.)                                                                        Lab - Gas Chromatography with
                                                                                                     Flame Photometric Detector
7. NON-VOLATILE RESIDUE
   a) Milliliters @ 100 DEG. F                                         0.05                          ASTM D-2158
   b) Oil Stain                                                        Pass

THE FOLLOWING TESTS ARE OPTIONAL,
  DEPENDING UPON THE PRODUCT SOURCE:

8. DRYNESS
   Freeze Valve, Seconds                                               60 (Note 2)                   ASTM D-2713

9. VOLATILE RESIDUE
   95% Evaporated - Temperature,                                       -37                           ASTM D-1837
     DEG. F

10. AMMONIA
    PPM by Weight in Liquid                                            1                             Field - Length of Stain Tube
                                                                                                     Lab - UOP 430
11. FLUORIDES
    PPM by Weight in Liquid as                                         5                             Field - Length of Stain Tube
    Monatomic Fluorine

12. OTHER DELETERIOUS SUBSTANCES
      (PPM BY WEIGHT IN LIQUID)
    Includes but not limited to                                        1                             Gas chromatography with flame
    (Isoprene, Butadiene, Vinyl                                                                      ionization or electron capture
    Chloride, glycol, amine, caustic)                                                                detection or other

</Table>

NOTES:   (1) The test methods for items 2 and 7 are not necessary if a
         compositional analysis is available which indicates compliance with
         these requirements.

         (2) The addition of methanol in the distribution system should be on a
         spot basis and must not exceed a rate of 5 Gallons per 10,000 Gallons
         of product.

                                       2
<Page>



                           NORMAL BUTANE SPECIFICATION

Product characteristics with test methods are herein specified for normal
butane received by Cedar Bayou Fractionators, L.P..

<Table>
<Caption>
                                                                                                         TEST METHODS
PRODUCT CHARACTERISTICS                               MINIMUM         MAXIMUM                            LATEST REVISION
-----------------------                               -------         -------                            ---------------
<S>                                                   <C>            <C>                                 <C>
1.  COMPOSITION                                                                                           ASTM E-260
    Percent by Liquid Volume
    Isobutane and Lighter                                              5.0                                ASTM D-2163
    Butylene (Percent of N. Butane)                                    1.0
    N. Butane & Butylene                                95.0           100                                GPA 2165
    Pentanes & Heavier                                                 2.0

2.  VAPOR PRESSURE
    Psig @ 100 DEG. F                                                  50                                 ASTM D-1267

3.  CORROSION
    Copper Strip @ 100 DEG. F                                          1-b                                ASTM D-1838
    (Invalid if additive or inhibitor is
    used.)
    Corrosion Additive or Inhibitor, PPM
    by Weight                                                          1                                  Applicable Industry
                                                                                                          Practices

4.  TOTAL SULFUR
    PPM by Weight in Liquid                                            140                                ASTM D-3246

5.  VOLATILE RESIDUE
    95% Evaporated - Temperature, DEG. F                               +36                                ASTM D-1837

6.  DRYNESS                                                            No Free Water                      Visual

</Table>

NOTE: The test methods for Items 2 and 5 are not necessary if a compositional
analysis indicates compliance with these requirements.

                                    3

<Page>

                             ISOBUTANE SPECIFICATION

Product characteristics with test methods are herein specified for isobutane
received by Cedar Bayou Fractionators, L.P..

<Table>
<Caption>

                                                                                                    TEST METHODS
PRODUCT CHARACTERISTICS                              MINIMUM               MAXIMUM                  LATEST REVISION
-----------------------                              -------               -------                  ---------------
<S>                                                  <C>                   <C>                      <C>
1. COMPOSITION                                                                                       ASTM E-260
   Percent by Liquid Volume
   Propane, Propylene and Lighter                                            3.0                     ASTM D-2163
   Isobutane                                          96.0                   100
   Butylene, Normal Butane & Heavier                                         4.0


2. VAPOR PRESSURE
   Psig @ 100 DEG. F                                                         62                      ASTM D-1267

3. CORROSION
   Copper Strip @ 100 DEG. F                                                 1-b                     ASTM D-1838
   (Invalid if additive or inhibitor is
   used.)
   Corrosion Additive or Inhibitor, PPM
   by Weight                                                                 1                       Applicable Industry Practices

4. TOTAL SULFUR
   PPM by Weight in Liquid                                                   140                     ASTM D-3246

5. VOLATILE RESIDUE
   95% Evaporated - Temperature DEG. F                                       +16                     ASTM D-1837

6. DRYNESS                                                                   No Free Water           Visual

</Table>

NOTE: The test methods for Items 2 and 5 are not necessary if an adequate
compositional analysis is available which indicates compliance with these
requirements.

                                                   4

<Page>

                                             NATURAL GASOLINE SPECIFICATION


Product characteristics with test methods are herein specified for natural
gasoline received by Cedar Bayou Fractionators, L.P..

<Table>
<Caption>

                                                                            TEST METHODS
PRODUCT CHARACTERISTICS                MINIMUM           MAXIMUM            LATEST REVISION
-----------------------                -------           -------            ---------------
<S>                                    <C>              <C>                 <C>
1. COMPOSITION                                                              ASTM E-260
   Percent by Liquid Volume
   Butanes and Lighter                                  3.0                 GPA 2165
   Pentanes & Heavier                   97              100

2. VAPOR PRESSURE
   Psi @ 100 DEG. F, Reid                               14                  ASTM D-323

3. CORROSION
   Copper Strip @ 104 DEG. F                            1-b                 ASTM D-130
   (Invalid if additive or
     inhibitor is used.)
   Corrosion Additive or
     Inhibitor, PPM by Weight.                          1                   Applicable Industry Practices

4. DOCTOR TEST                                          Negative            GPA 1138

5. DRYNESS                                              No Free Water       Visual

6. COLOR                                +25             No Color            Field White Cup Method
                                                                            Lab - ASTM D-156
7. DISTILLATION
   End Point, DEG. F                                    375                 ASTM D-216

</Table>

NOTE: The test methods for Items 2 and 7 are not necessary if an adequate
compositional analysis is available which indicates compliance with these
requirements.

                                                   5
<Page>

                       'Confidential Treatment Requested'

                                   EXHIBIT "C"
                                       to
                             Fractionation Agreement
                                 by and between
                         Cedar Bayou Fractionators, L.P.
                                       and
                 Williams Energy Marketing & Trading Company


                        STORAGE OF SPECIFICATION PRODUCTS

  1.  STORAGE       Williams shall have the right to store during any calendar
      VOLUME:       Month a total volume of Specification Products equal to the
                    component volume of Specification Products contained in the
                    Raw Product delivered to Cedar Bayou Fractionators, L.P.
                    ("CBF") in the preceding calendar Month.

* 2.  STORAGE       [REDACTED] per Month
      RATE:

  3.  RECEIPT FEE:  None. All volumes of Specification Products will be
                    delivered from the CBF Fractionator

  4.  EXCESS        For all volumes of Specification Products in Williams'
      STORAGE:      account at Month-end in excess of the Storage Volume,
                    excluding undelivered volumes for which timely
                    distribution instructions have been given, CBF has the
*                   right to charge an excess storage fee of [REDACTED] per
                    Gallon. Williams shall be required to obtain CBF's consent
                    prior to exceeding the Storage Volume.

* 5.  RETURN        [REDACTED].
      PERCENTAGE:

  6.  REDELIVERY    No charge for redelivery of Specification Product(s)
      FEES:         to the following locations: Texas Eastern Transmission,
                    Enron, Enterprise and Diamond-Koch. Williams shall have
                    the right to tender propane (subject to Dynegy's allocation
                    procedures) into the Dixie Pipeline for a delivery fee
*                   of [REDACTED] cents per Barrel. Such Dixie Pipeline
                    tenders shall be limited to the lesser of (i) the amount of
                    propane component in the Raw Product delivered by Williams
*                   to CBF in the preceding calendar Month, (ii) [REDACTED]
                    Barrels or (iii) the maximum amount allowed based on
                    Dynegy's allocation procedures. No charge for in-storage
                    transfers made by Williams to third parties who have the
                    right to store Specification Product(s) in the Storage
                    Facility.

                                             1
<Page>

                       'Confidential Treatment Requested'

  7.  TRUCK AND    CBF will load or cause to be loaded Specification Product(s)
*     TANK CAR     into trucks and tank cars for [REDACTED] cents per Gallon.
      LOADING      For any Specification Product(s) which are odorized by or
      AND          on behalf of CBF, Williams shall pay a fee to CBF of
*     UNLOADING    [REDACTED] cents per Gallon.
      FEES:

* 8.  THROUGHPUT   [REDACTED]
      CHARGES

  9.  SCHEDULING   Williams shall be required to schedule all movements of
                   Specification Products through Dynegy's Product Movement
                   Group. For physical deliveries of Specification Products
                   out of the Storage Facility, Williams must give distribution
                   instructions to Dynegy's Product Movement Group on or prior
                   to the 12th Day of the Month to assure deliveries of such
                   Specification Products by the end of such Month. For title
                   transfers of Specification Products within the Storage
                   Facility, Williams must give Dynegy transfer instructions
                   on or prior to the last Day of the Month to assure transfers
                   of such Specification Products by the end of such Month.

                                             2