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             $450 MM NORTHERN NATURAL GAS COMPANY REVOLVING FACILITY


BORROWER:                         Northern Natural Gas Company (the "Borrower").

GUARANTOR:                        Enron Corp.

FACILITY:                         Secured $450 million revolving credit
                                  facility, of which approximately $115,000,000
                                  of Citibank, N.A.'s initial advances shall be
                                  deemed to be conversions of the obligations
                                  assumed under the Assumption Documents (as
                                  defined in the Commitment Letter) (the
                                  "Assumption Obligations") and, upon such
                                  conversion, the obligations assumed under the
                                  Assumption Documents shall be cancelled (the
                                  "Facility"). Citibank, N.A., The Chase
                                  Manhattan Bank and the Borrower will determine
                                  the appropriate structure for the conversion
                                  of the Assumption Obligations in the Credit
                                  Agreement.

ACCORDION FEATURE:                Provided no default exists at such time, the
                                  Borrower may, without consent of the Lenders,
                                  increase the size of the Facility to an amount
                                  not to exceed $550 million. No Lender is in
                                  any way obligated to participate in such
                                  increase by increasing its own commitment
                                  amount, which decision shall be made in the
                                  sole discretion of each Lender at the time the
                                  Borrower elects to exercise its option to
                                  increase the Facility.

PAYING AGENT:                     Citibank, N.A.

CO-ARRANGERS:                     Salomon Smith Barney Inc. and J.P. Morgan
                                  Securities Inc.

CO-ADMINISTRATIVE AGENTS:         The Chase Manhattan Bank and Citibank, N.A..

LENDERS:                          Citibank, N.A. and The Chase Manhattan Bank
                                  and such other Lenders acceptable to Citibank,
                                  N.A. and The Chase Manhattan Bank.

SECURITY:                         A first priority perfected security interest
                                  securing the obligations under the Facility in
                                  (i) all capital stock of the Borrower; (ii) an
                                  unsecured subordinated intercompany note by
                                  Enron Corp. payable to the order of the
                                  Borrower ("Intercompany Note"); and (iii)
                                  subject to agreed exceptions, all other assets
                                  of the Borrower ("Collateral").

USE OF PROCEEDS:                  Working capital and loans to Enron Corp., such
                                  loans to be subordinated to all other debt of
                                  Enron Corp.

MATURITY DATE:                    364 days after the Closing Date.


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CLOSING DATE:                     On or before November 16, 2001 or, with the
                                  consent of Citibank, N.A. and The Chase
                                  Manhattan Bank, such other date on which
                                  Citibank, N.A. and The Chase Manhattan Bank
                                  shall be satisfied that all conditions
                                  precedent set forth in the Commitment Letter
                                  have been met.


INTEREST RATES
AND FEES:                         At the Borrower's option, Advances will be
                                  available to it at the rates and for the
                                  Interest Periods set forth below:

                                  (a) Base Rate Option: Base Rate plus 1.50%.

                                      The Base Rate is a fluctuating rate per
                                      annum equal at all times to the highest
                                      of: (i) Citibank's publicly announced
                                      "base rate", (ii) 1/2 of 1% per annum
                                      above the latest three-week moving average
                                      of secondary market morning offering rates
                                      in the United States for three-month
                                      certificates of deposit of major U.S.
                                      money center banks, adjusted for reserve
                                      requirements and FDIC assessment rates,
                                      and (iii) 1/2 of 1% per annum above the
                                      weighted average of the rates on overnight
                                      Federal funds transactions with members of
                                      the Federal Reserve System arranged by
                                      Federal funds brokers.

                                  (b) Eurodollar Rate Option: LIBOR plus 2.50%.

                                      LIBOR is the rate per annum (rounded
                                      upward to the nearest 1/100 of 1% per
                                      annum) appearing on Telerate Page 3750 (or
                                      any successor page) as the London
                                      interbank offered rate for deposits in
                                      dollars at approximately 11:00 a.m.
                                      (London time) two business days before the
                                      first day of the relevant Interest Period
                                      for a term comparable to such Interest
                                      Period. If for any reason such rate is not
                                      available, LIBOR shall be the rate per
                                      annum (rounded upward to the nearest 1/100
                                      of 1% per annum) appearing on Reuters
                                      Screen LIBO page as the London interbank
                                      offered rate for deposits in dollars at
                                      approximately 11:00 a.m. (London time) two
                                      business days before the first day of the
                                      relevant Interest Period for a term
                                      comparable to such Interest Period;
                                      provided, however, if more than one rate
                                      is specified on Reuters Screen LIBO page,
                                      the applicable rate shall be the
                                      arithmetic mean of all such rates. If
                                      neither the Telerate Page 3750 nor the
                                      Reuters Screen LIBO page rate is
                                      available, then LIBOR shall be the rate
                                      per annum at which dollar deposits are
                                      offered by the principal office of
                                      Citibank in London to prime banks in the
                                      London interbank market at 11:00 A.M.
                                      (London


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                                      time) two business days before the first
                                      day of the relevant Interest Period and
                                      with a maturity equal to such Interest
                                      Period. The Borrower may select Interest
                                      Periods of 1, 2 or 3 months for LIBOR
                                      Advances. The Borrower will reimburse each
                                      Lender, upon demand, for the cost of
                                      reserve requirements actually incurred.

DEFAULT RATE:                     When an event of default exists, all unpaid
                                  amounts under the Facility will bear interest
                                  payable on demand at the Base Rate plus 3.50%.

COMMITMENT FEE:                   A commitment fee of 0.50% per annum shall
                                  accrue on the daily average unused
                                  commitments.

INTEREST AND FEE
PAYMENTS:                         Interest on Base Rate Advances and commitment
                                  fees will be payable quarterly in arrears.
                                  Interest on LIBOR Advances will be payable at
                                  the end of the relevant Interest Period.
                                  Interest will be computed on a 365/366-day
                                  basis for Base Rate Advances and on a 360-day
                                  basis for LIBOR Advances. Commitment fees will
                                  be computed on a 360-day basis.

BORROWINGS:                       Borrowings shall be in minimum principal
                                  amounts of $25,000,000 for LIBOR Advances and
                                  $10,000,000 for Base Rate Advances. All
                                  Advances under the Facility will be made by
                                  the Lenders ratably in proportion to their
                                  respective commitments in the Facility.
                                  Borrowings will be available on same day
                                  notice (by 11:00 a.m. New York City time) for
                                  Base Rate Advances and three business days'
                                  notice for Eurodollar Rate Advances. On the
                                  Closing Date the Borrower shall request an
                                  initial Borrowing of an amount sufficient to
                                  convert all the Assumption Obligations to
                                  advances.

OPTIONAL PREPAYMENTS:             Advances may be prepaid in an amount of at
                                  least $10,000,000 on same day notice for Base
                                  Rate Advances and three business days notice
                                  for LIBOR Advances. The Borrower will bear all
                                  losses and costs (but not lost profits)
                                  related to prepayment of LIBOR Advances prior
                                  to the last day of the relevant Interest
                                  Period.

MANDATORY PREPAYMENTS:            Subject to agreed exceptions, the Advances
                                  shall be paid and the commitments permanently
                                  reduced by an amount equal to the net cash
                                  proceeds the Borrower receives from (i) any
                                  asset sales, (ii) equity issuances, or (iii)
                                  capital markets transactions.


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CONDITIONS PRECEDENT
TO CLOSING:                       Customary for financings of this nature,
                                  including:

                                      (a) the execution and delivery of the
                                  following, in form and substance satisfactory
                                  to the Co-Administrative Agents, for the
                                  Facility: (i) a credit agreement, (ii)
                                  certificates with respect to resolutions,
                                  charter, by-laws, incumbency and signatures
                                  and certified copies of all other relevant
                                  documents evidencing any necessary corporate
                                  action and governmental approvals, (iii) all
                                  security documents necessary to obtain a first
                                  perfected security interest (subject to agreed
                                  exceptions) in the Collateral securing the
                                  Facility only (other than certain of the
                                  Borrower's real estate and pipelines and
                                  fixtures that the Co-Administrative Agents
                                  agree may be obtained after the Closing Date
                                  ("Post-Closing Collateral")), including
                                  execution and delivery of pledge agreements
                                  covering all of the Borrower's capital stock
                                  and the Intercompany Note and a security
                                  agreement covering all the Borrower's personal
                                  property, (iv) a solvency and corporate
                                  separateness certificate by the Borrower's
                                  chief financial officer, and (v) favorable
                                  legal opinions from counsel for the Borrower
                                  and Enron Corp., including an opinion as to
                                  the enforceability of all loan documents and
                                  the perfection and enforceability of the
                                  security interests and an opinion regarding
                                  governmental approvals for the Facility (such
                                  opinions to be subject to customary exceptions
                                  and qualifications including bankruptcy,
                                  preference, fraudulent transfer or conveyance,
                                  equitable principles, and customary
                                  qualifications as to the enforceability of
                                  indemnities); and

                                      (b) (i) the Paying Agent's obtaining a
                                  first perfected security interest, subject to
                                  agreed exceptions, in the Collateral (other
                                  than the Post-Closing Collateral), and (ii)
                                  receipt of all charters, bylaws, partnership
                                  agreements, or other similar documents for
                                  each of Enron Corp.'s subsidiaries that
                                  directly or indirectly has any interest in the
                                  Borrower.

POST-CLOSING REQUIREMENT:         Within 60 days (except as agreed) after the
                                  Closing Date, (i) the Borrower shall have
                                  executed all security documents necessary to
                                  obtain a first perfected security interest
                                  (subject to agreed exceptions) securing the
                                  Facility only in the Post-Closing Collateral
                                  and (ii) the Paying Agent shall have received
                                  satisfactory opinions of counsel with respect
                                  thereto.

CONDITIONS PRECEDENT TO
INITIAL ADVANCE:                  o   Enron Corp. shall have a rating of at
                                      least BBB- and Baa3 by S&P and Moody's,
                                      respectively, and if such rating is BBB-
                                      and Baa3, such rating must be accompanied
                                      with a "stable" outlook ("Investment
                                      Grade").

                                  o   Neither Co-Administrative Agent shall have
                                      determined that, except as publicly
                                      disclosed or disclosed in writing to the
                                      Co-Administrative Agents before the
                                      execution of the Commitment


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                                      Letter, since December 31, 2000 a material
                                      adverse change in the business, condition
                                      (financial or otherwise), operations,
                                      performance, properties or prospects of
                                      Enron Corp. and its subsidiaries, taken as
                                      a whole, shall have occurred.

CONDITIONS PRECEDENT TO
ALL ADVANCES:                 Customary for financings of this nature, including
                              the following:

                                  o   All representations and warranties are
                                      correct on and as of the date of the
                                      borrowing before and after giving effect
                                      to such borrowing and to the application
                                      of the proceeds therefrom (other than
                                      those representations and warranties that
                                      expressly relate solely to a specific
                                      earlier date, which shall remain correct
                                      as of such earlier date), as though made
                                      on and as of such date.

                                  o   No event or condition exists or would
                                      result from such borrowing which
                                      constitutes an event of default or would
                                      constitute an event of default but for the
                                      requirement that notice be given or time
                                      elapse or both.

                                  o   The Paying Agent shall have received such
                                      other approvals, opinions or documents as
                                      any Lender through the Paying Agent may
                                      reasonably request.

REPRESENTATIONS
AND WARRANTIES OF THE
BORROWER:                     Usual and customary for transactions of this
                              nature, including but not limited to: (i)
                              confirmation of corporate status and authority of
                              the Borrower and its subsidiaries, (ii)
                              documentation and performance duly authorized and
                              do not contravene laws, corporate documents,
                              judgments, orders or material agreements, (iii)
                              documentation, including the Corporate Amendment
                              Documents and the Assumption Documents, are legal,
                              valid, binding and enforceable, (iv) financial
                              statements, (v) since December 31, 2000, no
                              material adverse change in the business, condition
                              (financial or otherwise), operations, performance,
                              properties or prospects of the Borrower and its
                              subsidiaries, taken as a whole, (vi) no litigation
                              having a material adverse effect, (vii) ERISA,
                              (viii) environmental condition, (ix) taxes, (x)
                              status under Investment Company Act and Public
                              Utility Holding Company Act, (xi) full and
                              complete disclosure, (xii) solvency, and (xiii)
                              corporate separateness.


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COVENANTS:                        Usual and customary for transactions of this
                                  nature including: (i) periodic financial
                                  statements, certificates of compliance with
                                  financial covenant, notice of default, certain
                                  ERISA information, and other information
                                  reasonably requested from time to time, (ii)
                                  compliance with laws, including environmental
                                  compliance, (iii) use of proceeds, (iv)
                                  maintenance of existence, (v) insurance, (vi)
                                  visitation rights, (vii) prohibition on liens
                                  and negative pledges subject to agreed
                                  exceptions, (viii) prohibition on debt subject
                                  to agreed exceptions, (ix) no sale, lease,
                                  transfer or other disposition of the
                                  Borrower's or any of its subsidiaries' assets
                                  with a value of more than $25,000,000 in the
                                  aggregate after the closing date or the
                                  Borrower's pipeline, (x) no merger or
                                  consolidation by the Borrower unless no
                                  default exists or results and the Borrower is
                                  survivor, (xi) limitation on investments,
                                  (xii) tangible net worth in accordance with
                                  GAAP of at least $750,000,000, (xiii) no
                                  change in lines of business, (xiv) corporate
                                  separateness, (xv) limitations on transactions
                                  with affiliates, (xvi) prohibition on
                                  distributions; (xvii) subject to agreed
                                  exceptions, prohibition on intercompany
                                  advances when a default has occurred and is
                                  continuing or would result therefrom, when the
                                  sum of the Borrower's unrestricted cash and
                                  the availability under the Facility after
                                  giving effect thereto is less than
                                  $30,000,000, or when Enron Corp. is no longer
                                  Investment Grade, (xviii) completion of
                                  expansion as disclosed to the
                                  Co-Administrative Agents, and (xix) no
                                  subsidiaries.

EVENTS OF DEFAULT:                Customary events of default for transactions
                                  of this nature, including: (i) failure to pay
                                  principal when due or interest and commitment
                                  fees after 5-day grace period, (ii)
                                  representations and warranties untrue when
                                  made, (iii) failure to comply with affirmative
                                  covenants if not cured within 30 days after
                                  written notice, (iv) failure to comply with
                                  negative covenants, (v) cross default or
                                  acceleration of Debt of the Borrower or a
                                  subsidiary for borrowed money greater than
                                  $10,000,000 or the occurrence and continuance
                                  of an Event of Default under the
                                  $1,750,000,000 364-Day Revolving Credit
                                  Agreement dated as of May 14, 2001 among Enron
                                  Corp., the banks party thereto and Citibank,
                                  N.A. and The Chase Manhattan Bank, as
                                  Co-Administrative Agents for such banks or the
                                  $1,250,000,000 Long-Term Revolving Credit
                                  Agreement dated as of May 18, 2000 among Enron
                                  Corp., the banks party thereto and Citibank,
                                  N.A. and The Chase Manhattan Bank, as
                                  Co-Administrative Agents for such banks, (vi)
                                  bankruptcy or insolvency of Enron Corp. or the
                                  Borrower or any of its subsidiaries, (vii) any
                                  unsatisfied judgment against the Borrower or
                                  any of its subsidiaries for payment of money
                                  greater than $10,000,000 unless enforcement
                                  stayed by appeal or otherwise, (viii)
                                  occurrence of certain circumstances respecting
                                  ERISA plans, (ix) except as agreed, Enron
                                  Corp. shall cease to own directly or
                                  indirectly 100% of the Borrower's capital
                                  stock, (x) an event of default under the
                                  Guaranty shall occur, (xi) any loan document,
                                  including the


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                                  Guaranty or a security document (subject to
                                  agreed exceptions), fails to remain in full
                                  force or effect or any action is taken to
                                  discontinue or to assert the invalidity or
                                  unenforceability thereof or any obligor under
                                  a loan document, including the Guaranty or a
                                  security document, shall disclaim an
                                  obligation thereunder, (xii) subject to agreed
                                  upon matters, any collateral document fails to
                                  create a valid and perfected first priority
                                  security interest (subject to agreed
                                  exceptions) in any Collateral purported to be
                                  covered thereby, or (xiii) the Borrower shall
                                  fail to comply with the terms of the Fee
                                  Letter.

GUARANTY:                         Unconditional guaranty of payment, not of
                                  collection. The Guaranty will include
                                  customary representations and warranties,
                                  including the following: (i) confirmation of
                                  corporate status and authority, (ii)
                                  documentation and performance duly authorized
                                  and do not contravene laws, corporate
                                  documents, judgments, orders or material
                                  agreements, (iii) documentation legal, valid,
                                  binding and enforceable, (iv) full disclosure,
                                  (v) corporate separateness between Enron Corp.
                                  and the Borrower, (vi) solvency, (vii) except
                                  as publicly disclosed or disclosed in writing
                                  to the Co-Administrative Agents before the
                                  execution of the Commitment Letter , since
                                  December 31, 2000 no material adverse change
                                  in the business, condition (financial or
                                  otherwise), operations, performance,
                                  properties or prospects of Enron Corp. and its
                                  subsidiaries, taken as a whole, has occurred.

                                  The Guaranty will also include customary
                                  affirmative and negative covenants, including
                                  (i) each of the covenants contained in Enron
                                  Corp.'s revolving credit agreements, as in
                                  effect from time to time, (ii) prohibition on
                                  liens and negative pledges for Enron Corp. and
                                  its subsidiaries subject to agreed exceptions,
                                  and (iii) maintenance of corporate
                                  separateness between Enron Corp. and the
                                  Borrower.

TRANSFERS AND
PARTICIPATIONS:                   Lenders permitted to assign commitments and
                                  loans under the Facility, in whole or part, to
                                  another Lender in the Facility, and, with the
                                  consent of the Paying Agents and, so long as
                                  no default exists, the Borrower (which
                                  consents shall not be unreasonably withheld),
                                  to a person that is not a Lender. Lenders may
                                  sell participations in the Facility provided
                                  that the assigning Lender retains all voting
                                  rights (except as specified in the definitive
                                  loan documentation) and all obligations under
                                  the Facility.

OTHER:                            The documentation will include customary
                                  agency language, and Majority Lenders for the
                                  Facility will be defined as those holding at
                                  least 66-2/3% of the Commitments under the
                                  Facility. The loan documentation will contain
                                  customary provisions regarding taxes,
                                  illegality, increased costs and capital


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                                  adequacy, subject to certain limitations, a
                                  waiver of jury trial, and a consent to New
                                  York jurisdiction.

EXPENSES; INDEMNITY:              All reasonable expenses incurred (i) by the
                                  Lenders in connection with the preparation,
                                  execution, delivery, modification, amendment
                                  and administration of the loan documentation
                                  (including reasonable fees and expenses of
                                  counsel to the Lenders) or (ii) by either
                                  Co-Administrative Agent or any Lender in
                                  connection with the enforcement of the loan
                                  documentation (including reasonable legal
                                  expenses), are for the Borrower's account. To
                                  the fullest extent permitted by law, the
                                  Borrower will indemnify and hold harmless each
                                  Co-Administrative Agent, each Lender and each
                                  of their respective officers, directors,
                                  employees and agents (each an "Indemnified
                                  Party") from and against any and all claims,
                                  damages, losses, liabilities and expenses
                                  (including reasonable fees and expenses of
                                  counsel) that may be incurred by or asserted
                                  against any Indemnified Party (other than by
                                  either Co-Administrative Agent or another
                                  Lender or any of their respective successors
                                  and assigns), in each case arising out of or
                                  in connection with any environmental claim or
                                  by reason of any investigation, litigation or
                                  proceeding arising out of, related to or in
                                  connection with the loan documentation or any
                                  transaction in which any proceeds of the
                                  Facility are applied, excluding any claim,
                                  damage, loss, liability or expense
                                  attributable to such Indemnified Party's gross
                                  negligence or willful misconduct. No
                                  Indemnified Party shall have any liability
                                  (whether in contract, tort or otherwise) to
                                  the Borrower or any of its security holders or
                                  creditors for or in connection with the
                                  transactions contemplated hereby, except for
                                  direct damages (as opposed to special,
                                  indirect, consequential or punitive damages
                                  (including, without limitation, any loss of
                                  profits, business or anticipated savings))
                                  resulting from such Indemnified Party's gross
                                  negligence or willful misconduct. Except as
                                  set forth in the next succeeding sentence,
                                  Borrower shall not have any liability to any
                                  Indemnified Party (whether in contract, tort
                                  or otherwise) in connection with the Facility
                                  for punitive, exemplary or treble damages. If
                                  (a) an Indemnified Party is required to pay
                                  damages of the type specified in the preceding
                                  sentence to another person (that is not an
                                  Indemnified Party), and (b) such Indemnified
                                  Party would be entitled to indemnification
                                  under this provision but for the limitation
                                  set forth in the preceding sentence, then the
                                  Indemnified Party shall nonetheless be
                                  entitled to indemnification for such Losses.

GOVERNING LAW:                    New York.

COUNSEL TO THE
CO-ADMINISTRATIVE AGENTS:         Bracewell & Patterson, L.L.P.


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