Document:

EXHIBIT 10.68

                             FISCAL AGENCY AGREEMENT

                                      Among

                          NORTHERN NATURAL GAS COMPANY,
                                     Issuer

                                  ENRON CORP.,
                                    Guarantor

                                       and

                     CONTINENTAL BANK, NATIONAL ASSOCIATION,
                                  Fiscal Agent

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                             Dated as of May 4, 1993

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                       6 7/8% Senior Notes due May 1, 2005

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                                TABLE OF CONTENTS

                                                                          Page

RECITALS OF THE ISSUER                                                         1
RECITALS OF THE GUARANTOR                                                      1
                  1.    The Securities                                         1
                        (a)      General                                       1
                        (b)      Form of Securities and Guarantees;
                                 Denominations of Securities                   2
                        (c)      Temporary Securities                          2
                        (d)      Legends                                       2
                        (e)      Book-Entry Provisions                         3
                  2.    Fiscal Agent; Other Agents                             3
                  3.    Authentication                                         4
                  4.    Payment and Cancellation                               4
                        (a) Payment                                            4
                        (b) Cancellation                                       5
                  5.    Exchange of Securities                                 5
                  6.    Register; Record Date for Certain Actions              6
                  7.    Delivery of Certain Information                        7
                        (a)      Non-Reporting Issuer                          7
                        (b)      Non-Reporting Guarantor                       7
                        (c)      Information After Three Years                 7
                        (d)      Periodic Reports                              8
                  8.    Conditions of Fiscal Agent's Obligations               8
                        (a)      Compensation and Indemnity                    8
                        (b)      Agency                                        9
                        (c)      Advice of Counsel                             9
                        (d)      Reliance                                      9
                        (e)      Interest in Securities, etc.                  9
                        (f)      Certifications                                9
                        (g)      No implied Obligations                        9
                        (h)      No Liability                                  9
                        (i)      No Inquiry                                    9
                  9.    Resignation and Appointment of Successor              10
                        (a)      Fiscal Agent and Paying Agent                10
                        (b)      Resignation                                  10
                        (c)      Successors                                   10
                        (d)      Acknowledgement                              11
                        (e)      Merger, Consolidation, etc.                  11
                  10.   Payment of Taxes                                      11

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                  11.   Assumption of the Securities by the Guarantor         11
                  12.   Amendments                                            12
                        (a)      Approval                                     12
                        (b)      Binding Nature of Amendments, Notice,
                                 Notations, etc.                              12
                        (c)      "Outstanding" Defined                        13
                  13.   Governing Law                                         13
                  14.   Notices                                               13
                  15.   Defeasance (Legal and Covenant)                       14
                        (a)      Issuer's and Guarantor's Option to
                                 Effect Defeasance or Covenant                14
                                 Defeasance
                        (b)      Defeasance and Discharge                     14
                        (c)      Covenant Defeasance                          14
                        (d)      Conditions to Defeasance and Covenant
                                 Defeasance                                   14
                        (e)      Deposit in Trust; Miscellaneous              16
                        (f)      Reinstatement                                16
                  16.   Headings                                              16
                  17.   Counterparts                                          16
                  18.   Successors and Assigns                                17
                  19.   Separability Clause                                   17

                        EXHIBIT A FORM OF SECURITY

                        EXHIBIT B FORM OF GUARANTEE

                        NOTE: This table of contents shall not be deemed to be
                        a part of the Fiscal Agency Agreement for any purpose.

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         FISCAL AGENCY AGREEMENT, dated as of May 4, 1993, among NORTHERN
NATURAL GAS COMPANY, a corporation duly organized under the laws of the State of
Delaware (the "Issuer"), ENRON CORP., a corporation duly organized under the
laws of the State of Delaware (the "Guarantor") and CONTINENTAL BANK, NATIONAL
ASSOCIATION, a national banking association duly organized and existing under
the laws of the United States of America, as Fiscal Agent.

                             RECITALS OF THE ISSUER

         The Issuer has duly authorized the creation of an issue of its 6 7/8%
Senior Notes due May 1, 2005 (herein called the "Securities") of substantially
the tenor and amount hereinafter set forth, and to provide therefor the Issuer
has duly authorized the execution and delivery of this Fiscal Agency Agreement.

         All things necessary to make the Securities, when executed by the
Issuer and authenticated and delivered hereunder and duly issued by the Issuer,
the valid obligations of the Issuer, and to make this Fiscal Agency Agreement a
valid agreement of the Issuer, in accordance with their and its terms, have been
done.

                            RECITALS OF THE GUARANTOR

         The Guarantor has duly authorized the Guarantees (as defined below)
provided for herein, and to provide therefor the Guarantor has duly authorized
the execution and delivery of this Fiscal Agency Agreement.

         All things necessary to make the Guarantees, when endorsed on the
Securities to which they relate and executed by the Guarantor, the valid
obligations of the Guarantor, and to make this Fiscal Agency Agreement a valid
agreement of the Guarantor, in accordance with their and its terms, have been
done.

         1. The Securities.

                  (a) General. The aggregate principal amount of Securities
which may be authenticated and delivered under this Agreement is limited to
$l00,000,000 except for Securities authenticated and delivered upon registration
of transfer, or in exchange for, or in lieu of other Securities pursuant to the
provisions of this Agreement or the Securities. The Securities will be
unconditionally guaranteed as to payment of principal and interest by the
Guarantor pursuant to guarantees (the "Guarantees") endorsed upon the Securities
and duly executed by the Guarantor.

         The Securities shall be known and designated as the 6 7/8% Senior Notes
due May 1, 2005 of the Issuer. The Securities will be unsecured, direct,
unconditional and general obligations of the Issuer and will rank pari passu
with all other unsecured and unsubordinated indebtedness of the Issuer. The
Securities will cease to be obligations of the Issuer if they are assumed by the
Guarantor pursuant to Section 11 hereof.

                                      -1-
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                  (b) Form of Securities and Guarantees; Denominations of
Securities. The Securities will be issued in registered form without coupons in
substantially the form of Exhibit A hereto and in minimum denominations of
$250,000 and in integral multiples of $1,000 in excess of $250,000. The
Guarantees will be in substantially the form of Exhibit B hereto. The Securities
and the Guarantees shall be executed manually or in facsimile on behalf of the
Issuer and the Guarantor, respectively, by its Chairman of the Board, President
or a Vice President and by its Secretary or an Assistant Secretary (the
"Authorized Officers"), notwithstanding that such officers, or any of them,
shall have ceased, for any reason, to hold such offices prior to the
authentication and delivery of such Securities or Guarantees, as the case may
be, or did not hold such offices at the date of such Securities or Guarantees,
as the case may be. The Securities and the Guarantees may also have such
additional provisions, omissions, variations or substitutions as are not
inconsistent with the provisions of this Agreement and may have such letters,
numbers or other marks of identification and such legends or endorsements placed
thereon as may be required to comply with any law or with any rules made
pursuant thereto or with the rules of any securities exchange or governmental
agency or as may, consistently herewith, be determined by the Authorized
Officers of the Issuer executing such Securities and the Authorized Officers of
the Guarantor executing the Guarantees endorsed thereon, as conclusively
evidenced by their execution of such Securities and Guarantees. All of the
Securities and the Guarantees shall be otherwise substantially identical except
as to denominations of Securities and as provided herein.

                  (c) Temporary Securities. Until definitive Securities with
Guarantees endorsed thereon are prepared, the Issuer may execute, and there
shall be authenticated and delivered in accordance with the provisions of
Section 3 hereof (in lieu of definitive printed Securities), temporary
Securities having Guarantees endorsed thereon. Such temporary Securities may be
in registered global form. Such temporary Securities shall be subject to the
same limitations and conditions and entitled to the same rights and benefits as
definitive Securities with Guarantees endorsed thereon, except as provided
herein or therein. Temporary Securities having Guarantees endorsed thereon shall
be exchangeable for definitive Securities with Guarantees endorsed thereon when
such definitive Securities are available for delivery; and upon the surrender
for exchange of such temporary Securities, the Issuer and the Guarantor shall
execute and there shall be authenticated and delivered, in accordance with the
provisions of Sections 5 and 6 hereof, in exchange for such temporary
Securities, a like aggregate principal amount of definitive Securities of like
tenor. The Issuer shall pay all charges, including (without limitation) stamp
and other taxes and governmental charges, incident to any exchange of temporary
Securities for definitive Securities. All temporary Securities shall be
identified as such and shall describe the right of the holder thereof to effect
an exchange for definitive Securities and the manner in which such an exchange
may be effected.

                  (d) Legends. Securities shall be stamped or otherwise be
imprinted with the legends set forth on the face of the text of the Securities
attached as Exhibit A hereto and any legend pursuant to Section 1(c) or 1(e)
hereof. The legends so provided on the face of the text of the Securities may be
removed from any Security, upon written order signed in the name of the Issuer
by its Chairman of the Board, President or a Vice President and by its Secretary
or an Assistant Secretary and delivered to the Fiscal Agent ("Order"), (i) three
years from the later of issuance of the Security or the date such Security (or
any predecessor) was last acquired from an "affiliate" of the Issuer or the
Guarantor within the meaning of Rule 144 under the Securities Act of 1933, as
amended, (the "Act") or (ii) in connection with a sale made pursuant to the
volume (and other restrictions) of Rule 144 under the Act following two years
from such time, provided that, if the legend is removed and the Security is
subsequently held by such an affiliate of the Issuer or the Guarantor, the
legend shall be reinstated. Any legends provided pursuant to Sections 1(c) and
(e) hereof may be removed as provided in such Sections.

                  (e) Book-Entry Provisions. This Section 1(e) shall apply only
to global Securities deposited with or on behalf of a depository located in the
United States (a "U.S. Depository").

                                      -2-

<PAGE>

         The Securities will be issued initially in the form of one or more
registered global Securities deposited with or on behalf of a U.S. Depository,
that (i) shall be registered in the name of the U.S. Depository for such global
Security or Securities or the nominee of such U.S. Depository, (ii) shall be
delivered by the Fiscal Agent to such U.S. Depository or pursuant to such U.S.
Depository's instruction and (iii) shall bear a legend substantially to the
following effect: "Unless this certificate is presented by an authorized
representative of [insert name and address of Depository] to the Issuer or its
agent for registration of transfer, exchange or payment, and any certificate
issued is registered in the name of [insert name of nominee of Depository], or
such other name as is requested by an authorized representative of [insert name
of Depository], and any payment hereon is made to [insert name of nominee of
Depository], ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY
OR TO ANY PERSON IS WRONGFUL, since the registered owner hereof, [insert name of
nominee of Depository], has an interest herein."

         Members of, or participants in, a U.S. Depository ("Agent Members")
shall have no rights under this Fiscal Agency Agreement with respect to any
global Security held on their behalf by a U.S. Depository or under the global
Security, and such U.S. Depository may be treated by the Issuer, the Guarantor,
the Fiscal Agent, and any agent of the Issuer, the Guarantor or the Fiscal Agent
as the owner of such global Security for all purposes whatsoever.
Notwithstanding the foregoing, nothing herein shall prevent the Issuer, the
Guarantor, the Fiscal Agent, or any agent of the Issuer, the Guarantor or the
Fiscal Agent, from giving effect to any written certification, proxy or other
authorization furnished by a U.S. Depository or impair, as between a U.S.
Depository and its Agent Members, the operation of customary practices governing
the exercise of the rights of a holder of any Security.

         So long as the U.S. Depository is the registered owner of Securities,
the U.S. Depository will for all purposes of the Securities and this Agreement
be considered the sole owner or holder of such Securities. Until such time as
definitive Securities may be issued, beneficial owners of Securities will not be
entitled to have Securities registered in their names, will not receive or be
entitled to receive physical delivery of Securities in definitive form, and will
not be considered the owners or holders thereof under this Agreement for any
purpose.

         If (i) the Issuer notifies the Fiscal Agent in writing that the U.S.
Depository is no longer willing or able to act as a depository and the Issuer is
unable to locate a qualified successor within 90 days or (ii) the Issuer
notifies the Fiscal Agent in writing to cause the issuance of Securities in
definitive form, then, upon surrender by the global Security holder of its
global Security, Securities in such form will be issued to each person that such
global Security holder and the U.S. Depository identifies as the beneficial
owner of the related Securities. Upon such issuance, the Fiscal Agent shall
register such Securities in the name of, and cause the same to be delivered to,
such person or persons (or the nominee thereof).

         2. Fiscal Agent; Other Agents.

         The Issuer and the Guarantor hereby appoint Continental Bank, National
Association acting through its corporate trust office at 231 South LaSalle
Street, Chicago, Illinois, as fiscal agent of the Issuer and the Guarantor, in
respect of the Securities and the Guarantees, upon the terms and subject to the
conditions herein set forth, and Continental Bank, National Association hereby
accepts such appointment. Continental Bank, National Association, and any
successor or successors as such fiscal agent qualified and appointed in
accordance with Section 8 hereof, are herein called the "Fiscal Agent." The
Fiscal Agent shall have the powers and authority granted to and conferred upon
it in the Securities and the Guarantees and hereby and such further powers and
authority to act on behalf of the Issuer and the Guarantor as may be mutually
agreed upon by the Issuer, the Guarantor and the Fiscal Agent. All of the terms
and provisions with respect to such powers and authority contained in the
Securities and the Guarantees are subject to and governed by the terms and
provisions hereof.

                                      -3-

<PAGE>

         The Issuer and Guarantor may appoint one or more agents (a "Paying
Agent" or "Paying Agents") for the payment (subject to applicable laws and
regulations) of the principal of and interest on the Securities, and one or more
agents (a "Transfer Agent" or "Transfer Agents") for the transfer and exchange
of Securities, at such place or places as the Issuer may determine; provided,
however, the Issuer shall at all times maintain a Paying Agent or agent thereof
and Transfer Agent or agent thereof in the Borough of Manhattan, The City of New
York (which Paying Agent and Transfer Agent may be the Fiscal Agent). The Issuer
and Guarantor initially appoint the Fiscal Agent as Paying Agent and Transfer
Agent. The Issuer shall promptly notify the Fiscal Agent of the name and address
of each Paying Agent and Transfer Agent appointed, and will notify the Fiscal
Agent of the resignation or termination of any Paying Agent or Transfer Agent.
Subject to the provisions of Section 9(c) hereof, the Issuer and Guarantor may
vary or terminate the appointment of any such Paying Agent or Transfer Agent at
any time and from time to time upon giving not less than 90 days' notice to such
Paying Agent or Transfer Agent, as the case may be, and to the Fiscal Agent.

         The Issuer shall cause notice of any resignation, termination or
appointment of any Paying Agent or Transfer Agent or of the Fiscal Agent and of
any change in the office through which any such Agent will act to be given as
provided in the text of the Securities.

         3.       Authentication.

         The Fiscal Agent is authorized, upon receipt of Securities duly
executed on behalf of the Issuer for the purposes of the original issuance of
the Securities, (i) to authenticate said Securities in an aggregate principal
amount not in excess of $100,000,000 and to deliver said Securities with
Guarantees endorsed thereon in accordance with an Order or Orders and (ii)
thereafter to authenticate and deliver said Securities with Guarantees endorsed
thereon in accordance with the provisions hereinafter set forth.

         The Fiscal Agent may, with the consent of the Issuer, appoint by an
instrument or instruments in writing one or more agents (which may include
itself) for the authentication of Securities and, with such consent, vary or
terminate any such appointment upon written notice and approve any change in the
office through which any authenticating agent acts. The Issuer (by written
notice to the Fiscal Agent and the authenticating agent whose appointment is to
be terminated) may also terminate any such appointment at any time. The Fiscal
Agent hereby agrees to solicit written acceptances from the entities concerned
(in form and substance satisfactory to the Issuer) of such appointments. In its
acceptance of such appointment, each such authenticating agent shall agree to
act as an authenticating agent pursuant to the terms and conditions of this
Agreement.

         4. Payment and Cancellation.

                  (a) Payment. Subject to the following provisions, the Issuer
shall provide to the Fiscal Agent in funds available on or prior to each date on
which a payment of principal of or any interest on the Securities shall become
due, as set forth in the text of the Securities, such amount, in such coin or
currency, as is necessary to make such payment, and the Issuer hereby authorizes
and directs the Fiscal Agent from funds so provided to it to make or cause to be
made payment of the principal of and interest, as the case may be, on the
Securities set forth herein and in the text of the Securities. The Fiscal Agent
shall arrange directly with any Paying Agent who may have been appointed
pursuant to the provisions of Section 2 hereof for the payment from funds so
paid by the Issuer of the principal of and interest on the Securities as set
forth herein and in the text of the Securities. Notwithstanding the foregoing,
the Issuer may provide directly to a Paying Agent funds for the payment of the
principal thereof and premium and interest, if any, payable thereon under an
agreement with respect to such funds containing substantially the same terms and
conditions set forth in this Section 4(a) and in Section 8(b) hereof; and the
Fiscal Agent shall have no responsibility with respect to any funds so provided
by the Issuer to any such Paying Agent.

                                      -4-

<PAGE>

         Any interest on the Securities shall be paid, unless otherwise provided
in the text of the Securities, to the persons (the "registered owners") in whose
names such Securities are registered on the register maintained pursuant to
Section 6 hereof at the close of business on the record dates designated in the
text of the Securities. Payments of principal of Securities shall be payable
against surrender thereof at the corporate trust office or office of an agent of
the Fiscal Agent and at the offices of such other Paying Agents as shall have
been appointed pursuant to Section 2 hereof. Payments of principal shall be made
against surrender of Securities, and payments of interest on Securities shall be
made, in accordance with the foregoing and subject to applicable laws and
regulations, by check mailed on or before the due date for such payment to the
person entitled thereto at such person's address appearing on the register of
the Securities maintained pursuant to Section 6 hereof, or, in the case of
payments of principal, to such other address as the registered owner shall
provide in writing at the time of such surrender; provided, however, that such
payments may be made, in the case of a registered owner of greater than
$1,000,000 aggregate principal amount of Securities, by transfer to an account
maintained by the payee with a bank if such registered owner so elects by giving
notice to the Fiscal Agent, not less than 15 days (or such fewer days as the
Fiscal Agent may accept at its discretion) prior to the date of the payments to
be obtained, of such election and of the account to which payment is to be made.

                  (b) Cancellation. All Securities delivered to the Fiscal Agent
(or any other Agent appointed pursuant to Section 2 hereof) for payment,
redemption, registration of transfer or exchange as herein or in the Securities
provided shall be forwarded to the Fiscal Agent by the Agent to which they are
delivered. All such Securities shall be cancelled and destroyed by the Fiscal
Agent or such other person as may be jointly designated by the Issuer and the
Fiscal Agent, which shall thereupon furnish certificates of such destruction to
the Issuer and Guarantor.

         5. Exchange of Securities.

         The Fiscal Agent, or its agent duly authorized by the Fiscal Agent, is
hereby authorized from time to time in accordance with the provisions of the
Securities, Section 1(e) and of this Section to authenticate and deliver:

         (i)      Securities in exchange for or in lieu of Securities of like
                  tenor and of like form which become mutilated, destroyed,
                  stolen or lost; and

         (ii)     registered Securities of authorized denominations in exchange
                  for a like aggregate principal amount of Securities of like
                  tenor and of like form.

         The Securities shall be dated the date of their authentication by the
Fiscal Agent. Each Security authenticated and delivered upon any transfer or
exchange for or in lieu of the whole or any part of any Security shall carry all
the rights if any, to interest accrued and unpaid and to accrue which were
carried by the whole or such part of such Security. All Securities issued in
exchange for Securities will have Guarantees endorsed thereon. Notwithstanding
anything to the contrary herein contained, such new Security shall be so dated
that neither gain nor loss in interest shall result from such transfer or
exchange.

         6. Register; Record Date for Certain Actions.

                                      -5-

<PAGE>
         The Fiscal Agent, as agent of the Issuer and the Guarantor, shall
maintain at its corporate trust office in Chicago, Illinois and at its agent's
office in the Borough of Manhattan, The City of New York, a register for the
Securities for the registration and registration of transfers of the Securities.
Upon presentation for the purpose at the said office of the Fiscal Agent or its
agent of any Security, accompanied by a written instrument of transfer in the
form approved by the Issuer, the Guarantor and the Fiscal Agent (it being
understood that, until notice to the contrary is given to holders of Securities,
the Issuer, the Guarantor and the Fiscal Agent shall each be deemed to have
approved the form of instrument of transfer, if any. printed on any definitive
Security), executed by the registered holder, in person or by such holder's
attorney thereunto duly authorized in writing, such Security shall be
transferred upon the register for the Securities, and a new Security of like
tenor shall be authenticated and issued with a Guarantee endorsed thereon in the
name of the transferee. Transfers and exchanges of Securities shall be subject
to Section 1(e), to such restrictions as shall be set forth in the text of the
Securities and to such reasonable regulations as may be prescribed by the
Issuer, the Fiscal Agent and the Guarantor. Successive registrations and
registrations of transfers as aforesaid may be made from time to time as desired
and each such registration shall be noted on the Security register. No service
charge shall be made for any registration, registration of transfer or exchange
of Securities, but, except as otherwise provided herein with respect to the
exchange of temporary Securities for definitive Securities, the Fiscal Agent
(and any Transfer Agent or authenticating agent appointed pursuant to Section 2
or 3 hereof, respectively) may require payment of a sum sufficient to cover any
stamp or other tax or governmental charge in connection therewith and any other
amounts required to be paid by the provisions of the Securities.

         Any Transfer Agent appointed pursuant to Section 2 hereof shall provide
to the Fiscal Agent such information as the Fiscal Agent may reasonably require
in connection with the delivery by such Transfer Agent of Securities in exchange
for other Securities.

         Neither the Fiscal Agent nor any Transfer Agent shall be required to
make registrations of transfer or exchange of Securities during any periods set
forth in the text of the Securities.

         Upon receipt by the Fiscal Agent of any written demand, request or
notice with respect to any matter on which the holders of Securities are
entitled to act under this Agreement, a record date shall be established for
determining holders of Outstanding Securities entitled to join in such demand,
request or notice, which record date shall be at the close of business on the
day the Fiscal Agent receives such demand, request or notice. The holders on
such record date, or their duly designated proxies, and only such persons, shall
be entitled to join in such demand, request or notice, whether or not such
holders remain holders after such record date; provided, however, unless the
holders of the requisite principal amount of the outstanding Securities shall
have joined in such demand, request or notice prior to the day which is the
ninetieth day after such record date, such demand, request or notice shall
automatically and without further action by any holder be cancelled and of no
further effect. Nothing in this paragraph shall prevent a holder, or a proxy of
a holder, from giving, (i) after expiration of such 90-day period, a new demand,
request or notice identical to a demand, request or notice which has been
cancelled pursuant to the proviso in the preceding sentence or (ii) during any
such 90-day period, a new demand, request or notice contrary to or different
from such demand, request or notice, in either of which events a new record date
shall be established pursuant to the provisions of this paragraph.

         The Issuer may, but shall not be obligated to, fix a record date for
the purpose of determining the persons entitled to consent to or approve any
action or waive any term, provision or condition of any covenant of this
Agreement. If a record date is fixed, the holders on such record date, or their
duly designated proxies, and only such persons, shall be entitled to consent to
or approve any such action or waive any such term, provision, condition or
covenant, whether or not such holders remain holders after such record date;
provided, however, that unless such consent, waiver or approval is obtained from
the requisite principal amount of holders of Outstanding Securities, or their
duly designated proxies, prior to the date which is the ninetieth day after such
record date, any such consent, waiver or approval previously given shall
automatically and without further action by any holder be cancelled and of no
further effect.

                                      -6-

<PAGE>

         7. Delivery of Certain Information.

                  (a) Non-Reporting Issuer. Subject to subsection (c), as long
as the Issuer is not subject to Section 13 or 15(d) of the Securities Exchange
Act of 1934, as amended ("Exchange Act"), at any time, upon the request of a
registered holder of a Security, the Issuer, or the Fiscal Agent upon request by
and at the expense of the Issuer, will promptly furnish or cause to be furnished
"Rule 144A Information" (as defined below) with respect to the Issuer to such
holder or to a prospective purchaser of such Security designated by such holder
in order to permit compliance by such holder with Rule 144A under the Act in
connection with the resale of such Security by such holder. "Rule 144A
Information" with respect to the Issuer or the Guarantor shall be such
information with respect to it as is specified pursuant to Rule 144A(d) (4) (i)
under the Act (or any successor provision thereto) which, at the date of this
Agreement, consists of (x) a very brief statement of the nature of the business,
products and services of the Issuer or the Guarantor, as the case may be, (which
statement shall be as of a date within 12 months prior to the date of the
intended resale) and (y) the most recent financial statements of the Issuer or
the Guarantor, as the case may be, and its financial statements for the two
fiscal years preceding the period covered in the most recent financial
statements. Such financial statements of the Issuer or the Guarantor, as the
case may be, shall include its balance sheet (as of a date less than 16 months
before the date of the intended resale) and its profit and loss and retained
earnings statements (for the twelve month period preceding the date of such
balance sheet and, if the balance sheet is not as of a date less than six months
before the date of the intended resale, the most recent profit and loss and
retained earnings statements shall be for the period from the date of such
balance sheet to a date less than six months before the date of the intended
resale) and shall be audited to the extent reasonably available.

                  (b) Non-Reporting Guarantor. Subject to subsection (c), at any
time that the Guarantor ceases to be subject to Section 13 or 15(d) of the
Exchange Act, upon the request of a registered holder of a Security, the
Guarantor, or the Fiscal Agent upon request by and at the expense of the
Guarantor; will promptly furnish or cause to be furnished Rule 144A Information
with respect to the Guarantor to such holder or to a prospective purchaser of
such Security designated by such holder in order to permit compliance by such
holder with Rule 144A under the Act in connection with the resale by such holder
of such Security with a Guarantee endorsed thereon.

                  (c) Information After Three Years. Neither the Issuer, the
Guarantor nor the Fiscal Agent shall be required to furnish Rule 144A
Information with respect to the Issuer or the Guarantor as contemplated by
subsections (a) and (b), (x) to the holder or a prospective purchaser of a
Security in connection with any request made on or after the date which is three
years from the later of (i) the date such Security (or any predecessor Security)
was acquired from the Issuer or the Guarantor or (ii) the date such Security (or
any predecessor Security) was last acquired from an "affiliate" of the Issuer or
the Guarantor within the meaning of Rule 144 under the Act or (y) at any time to
a prospective purchaser located outside the United States who is not a "U.S.
person" within the meaning of Regulation S under the Act.

                                      -7-

<PAGE>

                  (d) Periodic Reports. So long as any Securities are
Outstanding (as defined in Section 12(c) hereof), each of the Issuer and the
Guarantor, or the Fiscal Agent upon request by and at the expense of the Issuer
or the Guarantor, as the case may be, will furnish or cause to be furnished to
holders of Securities and to the Fiscal Agent, (i) at any time when the Issuer
or the Guarantor, as the case may be, is subject to Section 13 or 15(d) of the
Exchange Act, copies of its annual and quarterly reports to stockholders and of
each report or definitive proxy statement filed with the Securities and Exchange
Commission (the "Commission") under the Exchange Act, such reports or statements
to be so furnished within 15 days after the due date for filing with the
Commission, and (ii) at any time when the Issuer or the Guarantor, as the case
may be, is not subject to Section 13 or 15(d) of the Exchange Act, (A) its
annual financial statements prepared in accordance with generally accepted
accounting principles applied consistently (except as otherwise noted therein)
with those of the prior years (together with notes thereto and a report thereon
by an independent accounting firm of established national reputation), such
report to be so furnished as soon as reasonably available and in any event
within 120 days after the end of the fiscal year covered thereby, (B) its
unaudited comparative financial statements for each of the first three fiscal
quarters and the corresponding quarter of the prior year prepared in accordance
with generally accepted accounting principles applied consistently (except as
otherwise noted therein) with those of the most recent annual financial
statements (which unaudited statements and related notes may be condensed to the
extent permitted by Form l0-Q under the Act or any successor form), such
statements to be so furnished as soon as reasonably available and in any event
within 60 days after the end of the fiscal quarter covered thereby, (C) any
other interim reports or financial statements prepared generally for its
nonaffiliated investors or lenders, such reports or statements to be so
furnished concurrently with their distribution to such investors or lenders, and
(D) at each time of delivery of the financial statements in (A), a certificate
("Officers' Certificate") signed by its Chairman of the Board, Vice Chairman of
the Board, President or a Vice President and by its Treasurer, Assistant
Treasurer, Secretary or an Assistant Secretary, and stating whether or not to
the best knowledge of the signers thereof the Issuer or the Guarantor, as the
case may be, is in default in the performance and observance of any of the
terms, provisions and conditions of the Securities or the Guarantees, as the
case may be, or this Agreement and, if the Issuer or the Guarantor shall be in
default, specifying all such defaults and the nature and status thereof of which
they may have knowledge.

         8. Conditions of Fiscal Agent's Obligations.

         The Fiscal Agent accepts its obligations herein set forth upon the
terms and conditions hereof, including the following, to all of which the Issuer
and the Guarantor agree and to all of which the rights of holders from time to
time of Securities are subject:

                  (a) Compensation and Indemnity. The Fiscal Agent shall be
entitled to reasonable compensation as agreed with the Issuer and the Guarantor
for all services rendered by it, and the Issuer and the Guarantor agree promptly
to pay such compensation and to reimburse the Fiscal Agent for the reasonable
out-of-pocket expenses (including reasonable counsel fees) incurred by it in
connection with its services hereunder. The Issuer and the Guarantor also agree
to indemnify the Fiscal Agent for, and to hold it harmless against, any loss,
liability or expense, incurred without negligence or bad faith, arising out of
or in connection with its acting as Fiscal Agent hereunder, as well as the
reasonable costs and expenses of defending against any claim of liability in the
premises. The obligations of the Issuer and the Guarantor under this Section
8(a) shall survive payment of all the Securities or the resignation or removal
of the Fiscal Agent.

                                      -8-

<PAGE>

                  (b) Agency. In acting under this Agreement and in connection
with the Securities, the Fiscal Agent is acting solely as agent of the Issuer
and the Guarantor and does not assume any responsibility for the correctness of
the recitals in the Securities or the Guarantees (except for the correctness of
the statement in its certificate of authentication on the Securities) or any
obligation or relationship of agency or trust, for or with any of the owners or
holders of the Securities, except that all funds held by the Fiscal Agent for
the payment of principal of and any interest on the Securities shall be held in
trust for such owners or holders, as the case may be, as set forth herein and in
the Securities; provided, however, that monies held in respect of the Securities
remaining unclaimed at the end of two years after the principal of all of the
Securities shall have become due and payable (whether at maturity or otherwise)
and monies sufficient therefor shall have been duly made available for payment
shall, together with any interest made available for payment thereon, be repaid
to the Issuer or the Guarantor, as the case may be, as provided and in the
manner set forth in the Securities. Upon such repayment, the aforesaid trust
with respect to the Securities shall terminate and all liability of the Fiscal
Agent and Paying Agents with respect to such funds shall thereupon cease.

                  (c) Advice of Counsel. The Fiscal Agent and any Paying Agent
or Transfer Agent appointed by the Issuer and Guarantor pursuant to Section 2
hereof may consult with their respective counsel or other counsel satisfactory
to them, and the opinion of such counsel shall be full and complete
authorization and protection in respect of any action taken or suffered by them
hereunder in good faith and without negligence and in accordance with such
opinion.

                  (d) Reliance. The Fiscal Agent and any Paying Agent or
Transfer Agent appointed by the Issuer and Guarantor pursuant to Section 2
hereof each shall be protected and shall incur no liability for or in respect of
any action taken or thing suffered by it in reliance upon any Security, notice,
direction, consent, certificate, affidavit, statement, or other paper or
document believed by it, in good faith and without negligence, to be genuine and
to have been passed or signed by the proper party or parties.

                  (e) Interest in Securities, etc. The Fiscal Agent, any
authenticating agent, and any Paying Agent or Transfer Agent appointed by the
Issuer and Guarantor pursuant to Section 2 hereof and their respective officers,
directors and employees may become the owners of, or acquire any interest in,
any Securities, with the same rights that they would have if they were not the
Fiscal Agent, such authenticating agent, such other Paying Agent or Transfer
Agent or such person, and may engage or be interested in any financial or other
transaction with the Issuer or the Guarantor, and may act on, or as depository,
trustee or agent for, any committee or body of holders of Securities or other
obligations of the Issuer or Guarantor, as freely as if they were not the Fiscal
Agent, such authenticating agent, such other Paying Agent or Transfer Agent or
such person.

                  (f) Certifications. Whenever in the administration of this
Agreement the Fiscal Agent shall deem it desirable that a matter be proved or
established prior to taking, suffering or omitting any action hereunder, the
Fiscal Agent (unless other evidence be herein specifically prescribed) may, in
the absence of bad faith or negligence on its part, rely upon a certificate
signed by any Authorized Officer of the Issuer or the Guarantor, as the case may
be, and delivered to the Fiscal Agent.

                  (g) No Implied Obligations. The duties and obligations of the
Fiscal Agent shall be determined solely by the express provisions of this
Agreement, and the Fiscal Agent shall not be liable except for the performance
of such duties and obligations as are specifically set forth in this Agreement,
and no implied covenants or obligations shall be read into this Agreement
against the Fiscal Agent.

                  (h) No Liability. The Fiscal Agent shall not be liable for any
interest on any funds held by the Fiscal Agent.

                  (i) No Inquiry. The Fiscal Agent shall not be bound to
ascertain or inquire as to the performance or observance of any of the terms,
conditions, covenants or agreements of the Securities or other documents on the
part of the Issuer or as to the existence of any event of default thereunder.

                                      -9-

<PAGE>

         9. Resignation and Appointment of Successor.

                  (a) Fiscal Agent and Paying Agent. The Issuer and Guarantor
agree, for the benefit of the holders from time to time of the Securities and
the Guarantees, that there shall at all times be a Fiscal Agent hereunder which
shall be a bank or trust company organized and doing business under the laws of
the United States of America, any state thereof or the District of Columbia, in
good standing and having an established place of business or agency in the
Borough of Manhattan, The City of New York, and authorized under such laws to
exercise corporate trust powers until all the Securities authenticated and
delivered hereunder (i) shall have been delivered to the Fiscal Agent for
cancellation or (ii) become due and payable and monies sufficient to pay the
principal of and any interest on the Securities shall have been made available
for payment and either paid or returned to the Issuer or the Guarantor, as the
case may be, as provided herein and in such Securities.

                  (b) Resignation. The Fiscal Agent may at any time resign by
giving written notice to the Issuer and the Guarantor of such intention on its
part, specifying the date on which its desired resignation shall become
effective, provided that such date shall not be less than three (3) months from
the date on which such notice is given, unless the Issuer and the Guarantor
agree to accept shorter notice. The Fiscal Agent hereunder may be removed at any
time by the filing with it of an instrument in writing signed on behalf of the
Issuer and the Guarantor and specifying such removal and the date when it shall
become effective. Notwithstanding the dates of effectiveness of resignation or
removal, as the case may be, to be specified in accordance with the preceding
sentences, such resignation or removal shall take effect only upon the
appointment by the Issuer and the Guarantor, as hereinafter provided, of a
successor Fiscal Agent (which, to qualify as such, shall be a bank or trust
company organized and doing business under the laws of the United States of
America, any state thereof or the District of Columbia, in good standing and
having and acting through an established place of business or agency in the
Borough of Manhattan, The City of New York, authorized under such laws to
exercise corporate trust powers and having a combined capital and surplus in
excess of U.S. $20,000,000) and the acceptance of such appointment by such
successor Fiscal Agent. Upon its resignation or removal, the Fiscal Agent shall
be entitled to payment by the Issuer pursuant to Section 8 hereof of
compensation for services rendered and to reimbursement of reasonable
out-of-pocket expenses incurred hereunder.

                  (c) Successors. In case at any time the Fiscal Agent or any
Paying Agent in respect of the Securities (if such Paying Agent is the only
Paying Agent located in a place where, by the terms of the Securities or this
Agreement, the Issuer is required to maintain a Paying Agent) shall resign, or
shall be removed, or shall become incapable of acting, or shall be adjudged
bankrupt or insolvent, or shall file a voluntary petition in bankruptcy or make
an assignment for the benefit of its creditors or consent to the appointment of
a receiver of all or any substantial part of its property, or shall admit in
writing its inability to pay or meet its debts as they severally mature, or if a
receiver of it or of all or any substantial part of its property shall be
appointed, or if an order of any court shall be entered approving any petition
filed by or against it under the provisions of the Federal Bankruptcy Act or
under the provisions of any similar legislation, or if a receiver of it or its
property shall be appointed, or if any public officer shall take charge or
control of it or of its property or affairs, for the purpose or rehabilitation,
conservation or liquidation, a successor Fiscal Agent or Paying Agent, as the
case may be, qualified as aforesaid, shall be appointed by the Issuer and the
Guarantor by an instrument in writing, filed with the successor Fiscal Agent or
Paying Agent, as the case may be, and the predecessor Fiscal Agent or Paying
Agent, as the case may be. Upon the appointment as aforesaid of a successor
Fiscal Agent or Paying Agent, as the case may be, and acceptance by such
successor of such appointment, the Fiscal Agent or Paying Agent, as the case may
be, so succeeded shall cease to be Fiscal Agent or Paying Agent, as the case may
be, hereunder. If no successor Fiscal Agent or other Paying Agent, as the case
may be, shall have been so appointed by the Issuer and the Guarantor and shall
have accepted appointment as hereinafter provided, and, in the case of such
other Paying Agent, if such other Paying Agent is the only Paying Agent located
in a place where, by the terms of the Securities or this Agreement, the Issuer
is required to maintain a Paying Agent, then any holder of a Security who has
been a bona fide holder of a Security for at least six months, on behalf of
himself and all others similarly situated, or the Fiscal Agent may petition any
court of competent jurisdiction for the appointment of a successor agent. The
Issuer and the Guarantor shall give prompt written notice to each other Paying
Agent of the appointment of a successor Fiscal Agent:

                                      -10-

<PAGE>

                  (d) Acknowledgement. Any successor Fiscal Agent appointed
hereunder shall execute, acknowledge and deliver to its predecessor and to the
Issuer and the Guarantor an instrument accepting such appointment hereunder, and
thereupon such successor Fiscal Agent, without any further act, deed or
conveyance, shall become vested with all the authority, rights, powers, trusts,
immunities, duties and obligations of such predecessor with like effect as if
originally named as Fiscal Agent hereunder, and such predecessor, upon payment
of its compensation, and reimbursement of its disbursements then unpaid, shall
thereupon become obligated to transfer, delivery and pay over, and such
successor Fiscal Agent shall be entitled to receive, all monies, securities,
books, records or other property on deposit with or held by such predecessor as
Fiscal Agent hereunder.

                  (e) Merger, Consolidation, etc. Any corporation into which the
Fiscal Agent hereunder may be merged, or any corporation resulting from any
merger or consolidation to which the Fiscal Agent shall be a party, or any
corporation to which the Fiscal Agent shall sell or otherwise transfer all or
substantially all the assets and business of the Fiscal Agent, provided that it
shall be qualified as aforesaid, shall be the successor Fiscal Agent under this
Agreement without the execution or filing of any paper or any further act on the
part of any of the parties hereto.

         10. Payment of Taxes.

         The Issuer or the Guarantor, as the case may be, will pay all stamp and
other duties, if any, which may be imposed by the United States of America or
any political subdivision thereof or taxing authority of or in the foregoing
with respect to this Agreement or the issuance of the Securities or the
Guarantees.

         11. Assumption of the Securities by the Guarantor.

         The Guarantor may assume the obligations of the Issuer (or any
corporation which shall have previously assumed the obligations of the Issuer
pursuant to Paragraph 8 of the Securities), under the Securities in whole but
not in part, at any time on or after November 12, 1993 for the due and punctual
payment of the principal of and interest on, the Securities and the performance
of every covenant of this Agreement and the Securities on the part of the Issuer
to be performed or observed, provided that as conditions to such assumption:

                  (a) the Guarantor shall expressly assume such obligations by
         an amendment to this Agreement, executed by the Guarantor, and
         delivered to the Fiscal Agent;

                  (b) the Guarantor shall have sent, or the Fiscal Agent upon
         request by and at the expense of the Guarantor shall have sent, to each
         holder of Securities at its address set forth in the Securities
         Register at least 30 days prior to the effectiveness of such assumption
         a notice stating that the Guarantor was electing to assume the Issuer's
         obligations under the Securities and this Agreement in accordance with
         this Section 11, setting forth the anticipated effective date of such
         assumption and stating that upon such assumption the Issuer will be
         released from its liability as obligor upon the Securities and this
         Agreement;

                  (c) the Guarantor shall deliver to the Fiscal Agent an opinion
         of counsel to the effect that holders of the Securities will not
         recognize gain or loss for U.S. Federal income tax purposes as a result
         of such assumption and that holders of the Securities will be subject
         to U.S. Federal income tax on the same amount, in the same manner and
         at the same times as would have been the case if such assumption had
         not occurred;

                  (d) immediately after giving effect to such transaction, no
         event of default, and no event which, after notice or lapse of time or
         both, would become an event of default, shall have occurred and be
         continuing; and

                  (e) the Guarantor shall have delivered to the Fiscal Agent an
         Officers' Certificate of the Guarantor and an opinion of counsel, each
         stating that such assumption and such amendment comply with this
         Section 11 and that all conditions precedent in this Agreement and in
         the Securities relating to such transaction have been complied with.

                                      -11-
<PAGE>

         Such assumption shall become effective on the date the conditions set
forth above are satisfied. Upon any such assumption, the Guarantor shall succeed
to, and be substituted for, and may exercise every right and power of, the
Issuer under this Agreement and in the Securities with the same effect as if the
Guarantor had been named as the Issuer herein and in the Securities, and the
Issuer (or any successor corporation which shall theretofore have become such),
shall be released from its liability as obligor upon the Securities and under
this Agreement. Upon such assumption by the Guarantor, the Securities will
become unsecured, direct, unconditional and general obligations of the Guarantor
ranking pari passu with all other unsecured and unsubordinated indebtedness of
the Guarantor.

         12.      Amendments.

                  (a) Approval. With the written consent of the registered
owners of not less than a majority in aggregate principal amount of the
Securities then Outstanding (or of such other percentage as may be set forth in
the text of the Securities with respect to the action being taken), the Issuer,
the Guarantor and the Fiscal Agent may modify, amend or supplement the terms of
the Securities, the Guarantees and this Agreement in any way, and the holders of
Securities may make, take or give any request, demand, authorization, direction,
notice, consent, waiver or other action provided by this Agreement or the
Securities to be made, given or taken by holders of Securities; provided,
however, that no such action may, without the consent of the holder of each
Security affected thereby, (A) change the due date for the payment of the
principal of or any installment of interest on any Security, (B) reduce the
principal amount of any Security or the interest rate thereon or any premium
payable upon the redemption thereof, (C) change the coin or currency in which or
the place at which payment with respect to interest or principal in respect of
Securities are payable as required by the proviso of the first sentence of
the second paragraph of Section 2 hereof, (D) modify the Guarantees in a manner
materially adverse to the holders of the Securities, or (E) reduce the
proportion of the principal amount of Securities, the consent of the holders of
which is necessary to modify, amend or supplement this Agreement or the terms
and conditions of the Securities or to make, take or give any request, demand,
authorization, direction, notice, consent, waiver or other action provided
hereby or thereby to be made, taken or given. The Issuer, the Guarantor and the
Fiscal Agent may, without the consent of any holder of Securities, amend this
Agreement, the Securities or the Guarantees for the purpose of curing any
ambiguity, or of curing, correcting or supplementing any defective provision
thereof, hereof, or in any manner which the Issuer, the Guarantor and the Fiscal
Agent may determine that shall not be inconsistent with the Securities and
Guarantees and shall not adversely affect the interest of any holder of
Securities and related Guarantees.

         It shall not be necessary for the consent of the holders of Securities
to approve the particular form of any proposed modification, amendment,
supplement, request, demand, authorization, direction, notice, consent, waiver
or other action, but it shall be sufficient if such consent shall approve the
substance thereof.

                  (b) Binding Nature of Amendments, Notice, Notations, etc. Any
instrument given by or on behalf of any holder of a Security in connection with
any consent to any such modification, amendment, supplement, request, demand,
authorization, direction, notice, consent, waiver or other action will be
irrevocable once given and will be conclusive and binding on all subsequent
holders of such Security or any Security issued directly or indirectly in
exchange or substitution therefor or in lieu thereof. Any such modification,
amendment, supplement, request, demand, authorization, direction, notice,
consent, waiver or other action will be conclusive and binding on all holders of
Securities, whether or not they have given such consent, and whether or not
notation of such modification, amendment, supplement, request, demand,
authorization, direction, notice, consent, waiver or other action is made upon
the Securities. Notice of any modification or amendment of, supplement to, or
request, demand, authorization, direction, notice, consent, waiver or other
action with respect to the Securities, the Guarantees or this Agreement (other
than for purposes of curing any ambiguity or of curing, correcting or
supplementing any defective provision hereof or thereof) shall be given to each
holder of Securities affected thereby, in all cases as provided in the
Securities.

                                      -12-

<PAGE>

         Securities authenticated and delivered after the effectiveness of any
such modification, amendment, supplement, request, demand, authorization,
direction, notice, consent, waiver or other action may bear a notation in the
form approved by the Fiscal Agent, the Issuer and the Guarantor as to any matter
provided for in such modification, amendment, supplement, request, demand,
authorization, direction, notice, consent, waiver or other action. New
Securities modified to conform, in the opinion of the Fiscal Agent, the Issuer
and the Guarantor, to any such modification, amendment, supplement, request,
demand, authorization, direction, notice, consent, waiver or other action may be
prepared by the Issuer and the Guarantor, authenticated by the Fiscal Agent (or
any authenticating agent appointed pursuant to Section 3 hereof) and delivered
in exchange for Outstanding Securities.

                  (c) "Outstanding" Defined. For purposes of the provisions of
this Agreement and the Securities, any Security authenticated and delivered
pursuant to this Agreement shall, as of any date of determination, be deemed to
be "Outstanding", except:

                      (i) Securities theretofore cancelled by the Fiscal Agent
         or delivered to the Fiscal Agent for cancellation or held by the Fiscal
         Agent for reissuance but not reissued by the Fiscal Agent;

                      (ii) Securities which have become due and payable at
         maturity or otherwise and with respect to which monies sufficient to
         pay the principal thereof and any interest thereon shall have been made
         available to the Fiscal Agent; or

                      (iii) Securities which have been defeased pursuant to
         Section 15(b) hereof; or

                      (iv) Securities in lieu of or in substitution for which
         other Securities shall have been authenticated and delivered pursuant
         to this Agreement;

provided, however, that in determining whether the holders of the requisite
principal amount of Outstanding Securities have consented to any request,
demand, authorization, direction, notice, consent, waiver, amendment,
modification or supplement hereunder, Securities owned directly or indirectly by
the Issuer or Guarantor or any affiliate of the Issuer or Guarantor shall be
disregarded and deemed not to be Outstanding.

         13. GOVERNING LAW.

         THIS AGREEMENT SHALL BE GOVERNED BY, AND INTERPRETED IN ACCORDANCE
WITH, THE LAWS OF THE STATE OF NEW YORK, UNITED STATES OF AMERICA.

         14. Notices.

         All notices or communications hereunder, except as herein otherwise
specifically provided, shall be in writing and if sent to the Fiscal Agent shall
be delivered, transmitted by facsimile, telexed or telegraphed to it at 231
South LaSalle Street, Chicago, Illinois 60697, Attention: Kathy Kruzich,
facsimile no. (312) 828-6052 or if sent to the Issuer shall be delivered,
transmitted by facsimile, telexed or telegraphed to it at 1400 Smith Street,
Houston, Texas 77002, Attention: Rodney L. Gray, Senior Vice President and
Treasurer, facsimile no. (713) 758-8093, or if sent to the Guarantor shall be
delivered, transmitted by facsimile, telexed or telegraphed to it at 1400 Smith
Street, Houston, Texas 77002, Attention: Rodney L. Gray, Senior Vice President,
Finance and Treasurer, facsimile no. (713) 758-8093. The foregoing addresses for
notices or communications may be changed by written notice given by the
addressee to each party hereto, and the addressee's address shall be deemed
changed for all purposes from and after the giving of such notice.

         If the Fiscal Agent shall receive any notice or demand addressed to the
Issuer or the Guarantor by the holder of a Security, the Fiscal Agent shall
promptly forward such notice or demand to the Issuer and the Guarantor.

                                      -13-

<PAGE>

         15. Defeasance (Legal and Covenant).

                  (a) Issuer's and Guarantor's Option to Effect Defeasance or
Covenant Defeasance. The Issuer and the Guarantor may at their option, by Order
of the Issuer and the Guarantor delivered to the Fiscal Agent, elect to have
either Section 15(b) or Section 15(c) applied to the Outstanding Securities and
related Guarantees upon compliance with the conditions set forth below in this
Section 15.

                  (b) Defeasance and Discharge. Upon exercise by the Issuer and
the Guarantor of the option provided in Section 15(a) applicable to this Section
15(b), the Issuer and the Guarantor shall be deemed to have been discharged from
their respective obligations with respect to the outstanding Securities and
related Guarantees on the date the conditions set forth below are satisfied
(hereinafter, "Defeasance"). For this purpose, such Defeasance means that the
Issuer or the Guarantor shall be deemed to have paid and discharged the entire
Indebtedness represented by the Outstanding Securities and to have satisfied all
their respective other obligations under such Securities, the related Guarantees
and this Agreement insofar as the Securities and Guarantees are concerned (and
the Issuer or the Guarantor, as the case may be, and the Fiscal Agent shall
execute proper instruments acknowledging the same), except for the following,
which shall survive until otherwise terminated or discharged hereunder: (i) the
rights of holders of the Securities to receive, solely from the trust fund
described in Section 15(d) and as more fully set forth in such Section, payments
in respect of the principal of and any interest on the Securities when such
payments are due, (ii) the Issuer's and Guarantor's respective obligations with
respect to the Securities under Sections 1(d), 2, 4(a), 5, 6, 7(a), 7(b), 9 and
10 of this Agreement and paragraphs 3, 4(a), 9 (insofar as it relates to
Sections 7(a) and 7(b) of this Agreement), 10 and 11 of the Securities and (iii)
this Section 15. Subject to compliance with this Section 15, the Issuer and
Guarantor may exercise their option under this Section 15(b) notwithstanding the
prior exercise of their option under Section 15(c).

                  (c) Covenant Defeasance. Upon the Issuer's or Guarantor's
exercise of the option provided in Section 15(a) applicable to this Section
15(c), the Issuer and Guarantor shall be released from their obligations under
paragraphs 6(c), 7, and 8(a)(iii) of the Securities on and after the date the
conditions set forth below are satisfied (hereinafter, "Covenant Defeasance").
For this purpose, such Covenant Defeasance means that the Issuer and Guarantor
may omit to comply with and shall have no liability in respect of any term,
condition or limitation set forth in any such Section, whether directly or
indirectly by reason of any reference elsewhere herein to any such Section or by
reason of any reference in any such Section to any other provision herein or in
any other document, but the remainder of the Issuer's and Guarantor's
obligations shall be unaffected thereby.

                  (d) Conditions to Defeasance and Covenant Defeasance. The
following shall be the conditions to application of either Section 15(b) or
Section 15(c) to the then Outstanding Securities:

                                      -14-

<PAGE>

                      (i) The Issuer or Guarantor shall irrevocably have
         deposited or caused to be deposited with a trustee, who may be the
         Fiscal Agent and who shall agree to comply with the provisions of this
         Section 15 applicable to it (the "Defeasance Trustee"), as trust funds
         in trust for the purpose of making the following payments, specifically
         pledged as security for, and dedicated solely to, the benefit of the
         holders of the Securities, (A) money in an amount, or (B) U.S.
         Government Obligations and/or Eligible Obligations which through the
         scheduled payment of principal and interest in respect thereof in
         accordance with their terms will provide, not later than one day before
         the due date of any payment, money in an amount, or (C) a combination
         thereof, sufficient, in the opinion of a nationally recognized firm of
         independent public accountants expressed in a written certification
         thereof delivered to the Defeasance Trustee, to pay and discharge, and
         which shall be applied by the Defeasance Trustee to pay and discharge,
         the principal of and each installment of interest on the Securities not
         later than one day before the stated maturity of such principal or
         installment of interest in accordance with the terms of this Agreement
         and of the Securities. For this purpose: "U.S. Government Obligations"
         means securities that are (x) direct obligations of the United States
         of America for the payment of which its full faith and credit are
         pledged or (y) obligations of a person controlled or supervised by and
         acting as an agency or instrumentality of the United States of America
         the payment of which is unconditionally guaranteed as a full faith and
         credit obligation by the United States of America, which, in either
         case, are not callable or redeemable at the option of the issuer
         thereof, and shall also include a depository receipt issued by a bank
         (as defined in Section 3(a)(2) of the Act) as custodian with respect to
         any such U.S. Government Obligation or a specific payment of principal
         of or interest on any such U.S. Government Obligation held by such
         custodian for the account of the holder of such depository receipt,
         provided that (except as required by law) such custodian is not
         authorized to make any deduction from the amount payable to the holder
         of such depository receipt from any amount received by the custodian in
         respect of the U.S. Government Obligation or the specific payment of
         principal of or interest on the U.S. Government Obligation evidenced by
         such depository receipt; and "Eligible Obligations" means interest
         bearing obligations as a result of the deposit of which the Securities
         are rated in the highest generic long-term debt rating category
         assigned to legally defeased debt by one or more nationally recognized
         rating agencies.

                      (ii) In the case of an election under Section 15(b), the
         Issuer and the Guarantor shall have delivered to the Defeasance Trustee
         an opinion of counsel stating that (x) the Issuer and the Guarantor
         have received from, or there has been published by, the U.S. Internal
         Revenue Service a ruling, or (y) since the date of this Agreement there
         has been a change in the applicable U.S. Federal income tax law, in
         either case to the effect that, and based thereon such opinion shall
         confirm that, the holders of the Outstanding Securities and related
         Guarantees will not recognize gain or loss for U.S. Federal income tax
         purposes as a result of such deposit, defeasance and discharge and will
         be subject to U.S. Federal income tax on the same amount, in the same
         manner and at the same times as would have been the case if such
         deposit, defeasance and discharge had not occurred.

                      (iii) In the case of an election under Section 15(c), the
         Issuer and the Guarantor shall have delivered to the Defeasance Trustee
         an opinion of counsel to the effect that the holders of the Outstanding
         Securities and related Guarantees will not recognize gain or loss for
         Federal income tax purposes as a result of such deposit and covenant
         defeasance and will be subject to Federal income tax on the same
         amount, in the same manner and at the same times as would have been the
         case if such deposit and covenant defeasance had not occurred.

                      (iv) No event of default under paragraph 6 of the
         Securities or event which with notice or lapse of time or both would
         become such an event of default shall have occurred and be continuing
         on the date of such deposit or, insofar as paragraphs 6(d) and (e) of
         the Securities are concerned, at any time during the period ending on
         the 121st day after the date of such deposit (it being understood that
         this condition shall not be deemed satisfied until the expiration of
         such period).

                      (v) Such defeasance or covenant defeasance shall not
         result in a breach or violation of, or constitute a default under, any
         other agreement or instrument to which the Issuer or the Guarantor is a
         party or by which it is bound.

                                      -15-
<PAGE>

                      (vi) The Issuer and the Guarantor shall each have
         delivered to the Fiscal Agent and the Defeasance Trustee an Officers'
         Certificate and an opinion of counsel, each stating that all conditions
         precedent provided for relating to either the defeasance under Section
         15(b) or the covenant defeasance under Section 15(c) (as the case may
         be) have been complied with.

                      (vii) Such defeasance or covenant defeasance shall not
         result in the trust arising from such deposit constituting an
         investment company as defined in the Investment Company Act of 1940, as
         amended, or such trust shall be qualified under such act or exempt from
         regulation thereunder.

                  (e) Deposit in Trust; Miscellaneous. All money, U.S.
Government Obligations and Eligible Obligations (including the proceeds thereof)
deposited with the Defeasance Trustee pursuant to Section 15(d) in respect of
the Securities shall be held in trust and applied by the Defeasance Trustee, in
accordance with the provisions of the Securities and this Agreement, to the
payment, either directly or through any Paying Agent as the Defeasance Trustee
may determine, to the holders of the Securities, of all sums due and to become
due thereon in respect of principal and any interest, but such money need not be
segregated from other funds except to the extent required by law. Any money
deposited with the Defeasance Trustee for the payment of the principal of or any
interest on any Security and remaining unclaimed for two years after such
principal or interest has become due and payable shall be paid to the Issuer or
Guarantor, as the case may be, upon Order; and the holder of such Security shall
thereafter, as an unsecured general creditor, look only to the Issuer or
Guarantor, as the case may be, for payment thereof, and all liability of the
Defeasance Trustee with respect to such trust money shall thereupon cease.

         The Issuer and the Guarantor shall pay and indemnify the Defeasance
Trustee against any tax, fee or other charge imposed on or assessed against the
U.S. Government Obligations or Eligible Obligations deposited pursuant to
Section 15(d) or the principal and interest received in respect thereof other
than any such tax, fee or other charge which by law is for the account of the
holders of the Outstanding Securities.

         Anything in this Section 15 to the contrary notwithstanding, the
Defeasance Trustee shall deliver or pay to the Issuer or Guarantor, as the case
may be, from time to time upon the request of the Issuer or Guarantor any money,
U.S. Government Obligations or Eligible Obligations held by it as provided in
Section 15(d) which, in the opinion of a nationally recognized firm of
independent public accountants expressed in a written certification thereof
delivered to the Defeasance Trustee, are in excess of the amount thereof which
would then be required to be deposited to effect an equivalent defeasance or
covenant defeasance.

                  (f) Reinstatement. If the Defeasance Trustee is unable to
apply any money in accordance with Section 15(b) or 15(c) by reason of any order
or judgment of any court or governmental authority enjoining, restraining or
otherwise prohibiting such application, then the Issuer's and Guarantor's
obligations under this Agreement and the Securities shall be revived and
reinstated as though no deposit had occurred pursuant to this Section 15 until
such time as the Defeasance Trustee is permitted to apply all such money in
accordance with Section 15(b) or 15(c); provided, however, that if the Issuer
and Guarantor make any payment of principal of or interest on any Security
following the reinstatement of their obligations, the Issuer and Guarantor shall
be subrogated to the rights of the holders of such Securities to receive such
payment from the money held by the Defeasance Trustee.

         16. Headings.

         The section headings herein are for convenience only and shall not
affect the construction hereof.

         17.      Counterparts.

         This Agreement may be executed in one or more counterparts, and by each
party separately on a separate counterpart, and each such counterpart when
executed and delivered shall be deemed to be an original. Such counterparts
shall together constitute one and the same instrument.

                                      -16-

<PAGE>

         18. Successors and Assigns.

         All covenants and agreements in this Agreement by the Company and the
Guarantor shall bind their respective successors and assigns, whether so
expressed or not.

         19.      Separability Clause.

         In case any provision in this Agreement or in the Securities shall be
invalid, illegal or unenforceable, the validity, legality and. enforceability of
the remaining provisions shall not in any way be affected or impaired thereby.

         IN WITNESS WHEREOF, the parties hereto have executed this Fiscal Agency
Agreement and affixed their respective corporate seals as of the date first
above written.

                                              NORTHERN NATURAL GAS COMPANY
[Corporate Seal]
                                              By:        /s/ Rodney L. Gray
                                              Name:      Rodney L. Gray
                                              Title:     Senior Vice President
                                                         and Treasurer

Attest:

By:        /s/ Elaine V. Overturf
Name:      Elaine V. Overturf
Title:     Deputy Corporate Secretary

                                              ENRON CORP.
[Corporate Seal]
                                              By:        /s/ Rodney L. Gray
                                              Name:      Rodney L. Gray
                                              Title:     Senior Vice President,
                                                         Finance and Treasurer

Attest:

By:         /s/ Elaine V. Overturf
Name:      Elaine V. Overturf
Title:     Deputy Corporate Secretary

                                               Continental Bank, National
                                               Association
[Corporate Seal]
                                               By:        /s/ Greg Jordan
                                                          Vice President

Attest:

By:   /s/ T. H. Linters
          Vice President

                                      -17-

<PAGE>

                                    EXHIBIT A

                                FORM OF SECURITY

                                                                 [Form of Face
                                                                  of Security]

         THIS SECURITY (OR ITS PREDECESSOR) WAS ORIGINALLY ISSUED IN A
TRANSACTION EXEMPT FROM REGISTRATION UNDER THE UNITED STATES SECURITIES ACT OF
1933, AS AMENDED (THE `ACT"), AND MAY NOT BE SOLD OR OTHERWISE TRANSFERRED IN
THE ABSENCE OF SUCH REGISTRATION OR AN APPLICABLE EXEMPTION THEREFROM AND IN ANY
EVENT MAY BE SOLD OR OTHERWISE TRANSFERRED ONLY IN ACCORDANCE WITH THE FISCAL
AGENCY AGREEMENT, COPIES OF WHICH ARE AVAILABLE FOR INSPECTION AT THE CORPORATE
TRUST OFFICE OF THE FISCAL AGENT. THE EXEMPTION PROVIDED BY RULE 144A UNDER THE
ACT MAY BE AVAILABLE TO PERMIT SALE OR TRANSFER OF THIS SECURITY TO QUALIFIED
INSTITUTIONAL BUYERS (WITHIN THE MEANING OF RULE 144A) WITHOUT REGISTRATION.

         EACH HOLDER OF THIS SECURITY REPRESENTS TO THE ISSUER THAT (A) SUCH
HOLDER WILL NOT SELL OR OTHERWISE TRANSFER THIS SECURITY (WITHOUT CONSENT OF THE
ISSUER) PRIOR TO THREE YEARS FROM THE LATER OF May 11, 1993 OR THE DATE ON WHICH
THIS SECURITY WAS LAST HELD BY AN AFFILIATE OF THE ISSUER OR THE GUARANTOR OTHER
THAN (I) TO A QUALIFIED INSTITUTIONAL BUYER IN A TRANSACTION COMPLYING WITH RULE
144A, (II) TO A NON-U.S. PERSON IN A TRANSACTION COMPLYING WITH REGULATION S
UNDER THE ACT, (III) FOLLOWING TWO YEARS FROM SUCH TIME, IN A TRANSACTION
COMPLYING WITH RULE 144 UNDER THE ACT, OR (IV) PURSUANT TO ANOTHER AVAILABLE
EXEMPTION FROM REGISTRATION UNDER THE ACT (IT BEING UNDERSTOOD THAT AS A
CONDITION TO THE REGISTRATION OF TRANSFER OF THIS SECURITY, THE ISSUER, THE
GUARANTOR OR THE FISCAL AGENT MAY, IN CIRCUMSTANCES THEY BELIEVE APPROPRIATE,
REQUIRE EVIDENCE AS TO COMPLIANCE WITH ANY SUCH EXEMPTION) AND THAT (B) THE
HOLDER WILL, AND EACH SUBSEQUENT HOLDER IS REQUIRED TO, NOTIFY ANY PURCHASER OF
THIS SECURITY FROM IT OF THE RESALE RESTRICTIONS REFERRED TO IN (A) ABOVE.

         THE FOREGOING LEGENDS MAY BE REMOVED FROM THE SECURITIES ON THE
CONDITIONS SPECIFIED IN THE FISCAL AGENCY AGREEMENT.

                                      A-1
<PAGE>

No. R- .........                                                  [Denomination]

                          NORTHERN NATURAL GAS COMPANY

                       6 7/8% Senior Notes due May 1, 2005

         NORTHERN NATURAL GAS COMPANY, a corporation duly organized under the
laws of the State of Delaware (herein called the "Issuer"), for value received,
hereby promises to pay to __________________ or registered assigns, the
principal sum of __________________ on May 1, 2005 and to pay interest thereon
from May 11, 1993 or from the most recent Interest Payment Date to which
interest has been paid or duly provided for, semi-annually in arrears on May 1
and November 1 in each year, commencing November 1, 1993 (each an "Interest
Payment Date"), at the rate of 6 7/8% per annum, until the principal hereof is
paid or made available for payment and (to the extent that the payment of such
interest shall be legally enforceable) at the rate per annum equal to the above
rate plus 1% per annum on any overdue principal and on any overdue installment
of interest. Interest on the Securities shall be computed on the basis of a
360-day year of twelve 30-day months. The interest so payable, and punctually
paid or duly provided for, on any Interest Payment Date will, as provided in the
Fiscal Agency Agreement hereinafter referred to, be paid to the person (the
"registered holder") in whose name this Security (or one or more predecessor
Securities) is registered at the close of business on the April 15 or October 15
(whether or not a business day), as the case may be (each a "Regular Record
Date"), next preceding such Interest Payment Date. Any such interest not so
punctually paid or duly provided for will forthwith cease to be payable to the
registered holder on such Regular Record Date and shall be paid to the person in
whose name this Security (or one or more predecessor Securities) is registered
at the close of business on a special record date for the payment of such
interest to be fixed by the Issuer, notice whereof shall be given to registered
holders of Securities not less than 10 days prior to such special record date.

         Principal of this Security shall be payable against surrender hereof at
the corporate trust office or office of an agent of the Fiscal Agent hereinafter
referred to or at such other offices or agencies as the Issuer and Enron Corp.,
a Delaware corporation (the "Guarantor"), may designate and at the offices of
such other Paying Agents as the Issuer and Guarantor shall have appointed
pursuant to the Fiscal Agency Agreement. Payments of principal shall be made
against surrender of this Security, and payments of interest on this Security
shall be made, in accordance with the foregoing and subject to applicable laws
and regulations, by check mailed on or before the due date for such payment to
the person entitled thereto at such person's address appearing on the
aforementioned register or, in the case of payments of principal to such other
address as the registered holder may specify upon such surrender; provided,
however, that any payments shall be made, in the case of a registered holder of
at least $1,000,000 aggregate principal amount of Securities, by transfer to an
account maintained by the payee with a bank if such registered holder so elects
by giving notice to the Fiscal Agent, not less than 15 days (or such fewer days
as the Fiscal Agent may accept at its discretion) prior to the date of the
payments to be obtained, of such election and of the account to which payments
are to be made. The Issuer covenants that until this Security has been delivered
to the Fiscal Agent for cancellation, or monies sufficient to pay the principal
of and interest on this Security have been made available for payment and either
paid or returned to the Issuer or Guarantor, as the case may be, as provided
herein, it will at all times maintain an established place of business or agency
in the Borough of Manhattan, The City of New York for the payment of the
principal of and interest on the Securities as herein provided.

         Reference is hereby made to the further provisions of this Security set
forth on the reverse hereof, which further provisions shall for all purposes
have the same effect as if set forth at this place.

         Unless the certificate of authentication hereon has been executed by
the Fiscal Agent by manual signature, neither this Security nor the Guarantee
endorsed hereon shall be valid or obligatory for any purpose.

                                      A-2
<PAGE>

         IN WITNESS WHEREOF, the Issuer has caused this instrument to be duly
executed in facsimile and its corporate seal to be affixed hereto.

Date:                                          NORTHERN NATURAL GAS COMPANY

                                               By: ____________________________
                                                      President and Chief
                                                      Executive Officer

[Corporate Seal]

Attest:

____________________________
Vice President and Secretary

         This is one of the Securities referred to in the within-mentioned
Fiscal Agency Agreement.

                                               Continental Bank, National,
                                               Association, as Fiscal Agent

                                               ______________________________
                                               By:

                                      A-3

<PAGE>

                                                               [Form of reverse
                                                                   of Security]

         1. This Security is one of a duly authorized issue of securities of the
Issuer designated as its 6 7/8% Senior Notes due May 1, 2005 (herein called the
"Securities"), unconditionally guaranteed as to payment of principal and
interest (the "Guarantees") by the Guarantor, limited in aggregate principal
amount to $100,000,000, issued and to be issued in accordance with a Fiscal
Agency Agreement, dated as of May 4, 1993 (herein called the "Fiscal Agency
Agreement"), among the Issuer, the Guarantor and Continental Bank, National
Association, as Fiscal Agent (herein called the "Fiscal Agent", which term
includes any successor fiscal agent under the Fiscal Agency Agreement), copies
of which Fiscal Agency Agreement are on file and available for inspection at the
corporate trust office of the Fiscal Agent which at the date hereof is at 231
South LaSalle Street, Chicago, Illinois.

                The Securities are unsecured direct, unconditional and general
obligations of the Issuer and will rank equally with all other unsecured and
unsubordinated indebtedness of the Issuer.

         2. The Securities are issuable only in fully registered form, without
coupons, in minimum denominations of U.S. $250,000 and integral multiples of
$1,000 above that amount.

         3. The Issuer and the Guarantor shall maintain in the Borough of
Manhattan, The City of New York, an established place of business or agency
where Securities may be surrendered for registration of transfer or exchange.
The Issuer and Guarantor have initially appointed the Fiscal Agent acting
through its corporate trust office in Chicago, Illinois and at its agent's
office in the Borough of Manhattan, The City of New York, as their agent for
such purpose and the Issuer and the Guarantor have agreed to cause to be kept at
such offices a register in which, subject to such reasonable regulations as it
may prescribe, the Issuer will provide for the registration of Securities and of
transfers of Securities. The Issuer and Guarantor reserve the right to vary or
terminate the appointment of the Fiscal Agent as security registrar or of any
Transfer Agent or to appoint additional or other registrars or Transfer Agents
or to approve any change in the office through which any security registrar or
any Transfer Agent acts, provided that there will at all times be a security
registrar or agent thereof in the Borough of Manhattan, The City of New York.
Registered holders of the Securities will receive notice of any such change.

                  The transfer of a Security is registrable on the
aforementioned register upon surrender of such Security at the corporate trust
office of the Fiscal Agent or the office of the agent of the Fiscal Agent or any
Transfer Agent duly endorsed by, or accompanied by a written instrument of
transfer in form satisfactory to the Issuer, the Guarantor and the Fiscal Agent
duly executed by, the registered holder thereof or his attorney duly authorized
in writing. Upon such surrender of this Security for registration of transfer,
the Issuer shall execute; and the Fiscal Agent shall authenticate and deliver,
in the name of the designated transferee or transferees, one or more new
Securities with Guarantees endorsed thereon, dated the date of authentication
thereof, of any authorized denominations and of a like aggregate principal
amount.

                  At the option of the registered holder upon request confirmed
in writing, Securities may be exchanged for Securities of any authorized
denominations and of a like tenor, form and aggregate principal amount upon
surrender of the Securities to be exchanged at the office of any Transfer Agent
or at the corporate trust office of the Fiscal Agent or agent thereof. Whenever
any Securities are so surrendered for exchange, the Issuer shall execute, and
the Fiscal Agent shall authenticate and deliver, the Securities with Guarantees
endorsed thereon which the registered holder making the exchange is entitled to
receive. Any registration of transfer or exchange will be effected upon the
Transfer Agent or the Fiscal Agent, as the case may be, being satisfied with the
documents of title and identity of the person making the request and subject to
such reasonable regulations as the Issuer and Guarantor may from time to time
agree with the Transfer Agent and the Fiscal Agent.

                                      A-4

<PAGE>

                  All Securities and the Guarantees endorsed thereon issued upon
any registration of transfer or exchange of Securities shall be the valid
obligations, of the Issuer and the Guarantor, respectively, evidencing the same
debt, and entitled to the same benefits, as the Securities and the Guarantees
endorsed thereon surrendered upon such registration of transfer or exchange. No
service charge shall be made for any registration of transfer or exchange, but
the Issuer and the Guarantor may require payment of a sum sufficient to cover
any tax or other governmental charge payable in connection therewith.

                  Prior to due presentment of this Security for registration of
transfer, the Issuer, the Guarantor, the Fiscal Agent and any agent of the
Issuer, the Guarantor or the Fiscal Agent may treat the person in whose name
this Security is registered as the owner hereof for all purposes, whether or not
this Security be overdue, and neither the Issuer, the Guarantor, the Fiscal
Agent nor any such agent shall be affected by notice to the contrary.

         4.     (a) The Issuer shall pay to the Fiscal Agent at its principal
office in Chicago, Illinois on or prior to each Interest Payment Date and the
maturity date of the Securities, in such amounts sufficient (with any amounts
then held by the Fiscal Agent and available for the purpose) to pay the interest
on and the principal of the Securities due and payable on such Interest Payment
Date or maturity date, as the case may be in funds available on such date. The
Fiscal Agent shall apply the amounts so paid to it to the payment of such
interest and principal in accordance with the terms of the Securities. Any
monies paid by the Issuer or the Guarantor, as the case may be to the Fiscal
Agent for the payment of the principal of or interest on any Securities and
remaining unclaimed at the end of two years after such principal or interest
shall have become due and payable (whether at maturity or otherwise) shall then
be repaid to the Issuer or the Guarantor, as the case may be, upon its written
request, and upon such repayment all liability of the Fiscal Agent with respect
thereto shall cease, without, however, limiting in any way any obligation the
Issuer or the Guarantor may have to pay the principal of and interest on this
Security as the same shall become due.

                  (b) In any case where the due date for the payment of the
principal of or interest on any Security shall be at any place of payment a day
on which banking institutions are authorized or obligated by law to close, then
payment of principal or interest need not be made on such date at such place but
may be made on the next succeeding day at such place which is not a day on which
banking institutions are authorized or obligated by law to close, with the same
force and effect as if made on the date for such payment, and no interest shall
accrue for the period after such date.

         5. The Issuer or the Guarantor, as the case may be, shall pay all stamp
and other duties, if any, which may be imposed by the United States or any
political subdivision thereof or taxing authority of or in the foregoing with
respect to the Fiscal Agency Agreement or the issuance of this Security. Except
as otherwise provided in this Security, neither the Issuer nor the Guarantor
shall be required to make any payment with respect to any tax, assessment or
other governmental charge imposed by any government or any political subdivision
or taxing authority thereof or therein.

         6. In the event of:

                  (a) default in the payment of any interest on any Security for
         a period of 30 days after the date when due; or

                  (b) default in the payment of the principal of any Security
         when due (whether at maturity or otherwise); or

                  (c) default in the performance or breach of any other covenant
         or agreement of the Issuer or the Guarantor contained in the Securities
         or the Guarantees or in the Fiscal Agency Agreement for a period of 60
         days after the date on which written notice of such default requiring
         the Issuer or the Guarantor to remedy the same and stating that such
         notice is a "Notice of Default" shall first have been given to the
         Issuer and the Fiscal Agent by the holders of at least 25% in principal
         amount of the Securities at the time Outstanding (as defined in the
         Fiscal Agency Agreement); or

                                      A-5

<PAGE>

                  (d) the entry by a court having jurisdiction in the premises
         of (i) a decree or order for relief in respect of the Issuer or the
         Guarantor in an involuntary case or proceeding under any applicable
         Federal or State bankruptcy, insolvency, reorganization or other
         similar law or (ii) a decree or order adjudging the Issuer or the
         Guarantor bankrupt or insolvent, or approving as properly filed a
         petition seeking reorganization, arrangement, adjustment or composition
         of or in respect of the Issuer or the Guarantor Under any applicable
         Federal or State law, or appointing a custodian, receiver, liquidator,
         assignee, trustee, sequestrator or other similar official of the Issuer
         or the Guarantor or of any substantial part of the property of the
         Issuer or the Guarantor, or ordering the winding up or liquidation of
         the affairs of the Issuer or the Guarantor, and any such decree or
         order for relief or any such other decree or order shall continue
         unstayed and in effect for a period of 60 consecutive days; or

                  (e) commencement by the Issuer or the Guarantor of a voluntary
         case or proceeding under any applicable Federal or State bankruptcy,
         insolvency, reorganization or other similar law or of any other case or
         proceeding to be adjudicated a bankrupt or insolvent, or the consent by
         the Issuer or the Guarantor to the entry of a decree or order for
         relief in respect of the Issuer or the Guarantor in an involuntary case
         or proceeding under any applicable Federal or State bankruptcy,
         insolvency, reorganization or other similar law or to the commencement
         of any bankruptcy or insolvency case or proceeding against the Issuer
         or the Guarantor, or the filing by the Issuer or the Guarantor of a
         petition or answer or consent seeking reorganization or relief under
         any such applicable Federal or State law, or the consent by the Issuer
         or the Guarantor to the filing of such petition or to the appointment
         of or the taking possession by a custodian, receiver, liquidator,
         assignee, trustee, sequestrator or other similar official of the Issuer
         or the Guarantor or of any substantial part of its property, or the
         making by the Issuer or the Guarantor of an assignment for the benefit
         of creditors, or the taking of action by the Issuer or the Guarantor in
         furtherance of any such action;

the registered holder of this Security may, at such holder's option, declare the
principal of this Security and the interest accrued hereon to be due and payable
immediately by written notice to the Issuer and the Fiscal Agent at its
corporate trust office, and unless all such defaults shall have been cured by
the Issuer or the Guarantor prior to receipt of such written notice, the
principal of the Security and the interest accrued thereon shall become and be
immediately due and payable. For purposes of the Securities, "Subsidiary" of the
Issuer or the Guarantor means a corporation all of the outstanding voting stock
of which is owned, directly or indirectly, by the Issuer or the Guarantor, as
the case may be, or by one or more other Subsidiaries, or by the Issuer or the
Guarantor, as the case may be, and/or one or more other Subsidiaries. For the
purposes of this definition, "voting stock" means stock which ordinarily has
voting power for the election of directors, whether at all times or only so long
as no senior class of stock has such voting power by reason of any contingency.

         7. So long as any of the Securities are Outstanding, neither the Issuer
nor the Guarantor will pledge, mortgage or hypothecate, or permit to exist, and
will not cause, suffer or permit any Subsidiary of it to pledge, mortgage or
hypothecate, or permit to exist, except in favor of the Issuer or the Guarantor,
as the case may be, or any Subsidiary of it, any mortgage, pledge or other lien
upon, any Principal Property (as hereinafter defined) at any time owned by it,
to secure any Indebtedness (as hereinafter defined) of it, without making
effective provision whereby the Outstanding Securities shall be equally and
ratably secured with any and all such Indebtedness of the Company and whereby
the Guarantees of Outstanding Securities will be equally and ratably secured
with any and all such Indebtedness of the Guarantor, as the case may be, and
with any other Indebtedness of it similarly entitled to be equally and ratably
secured; provided, however, that this restriction shall not apply to or prevent
the creation or existence of:

                  (i) undetermined or inchoate liens and charges incidental to
         construction, maintenance, development or operation;

                  (ii) any liens of taxes and assessments for the then current
         year;

                  (iii) any liens of taxes and assessments not at the time
         delinquent;

                                      A-6

<PAGE>

                  (iv) any liens of specified taxes and assessments which are
         delinquent but the validity of which is being contested in good faith
         at the time by the Issuer or the Guarantor, as the case may be, or any
         Subsidiary of it;

                  (v) any liens reserved in leases for rent and for compliance
         with the terms of the lease in the case of leasehold estates;

                  (vi) any obligations or duties, affecting the property of the
         Issuer or the Guarantor, as the case may be, or any Subsidiary of it,
         to any municipality or public authority with respect to any franchise,
         grant, license, permit or similar arrangement;

                  (vii) the liens of any judgments or attachments in an
         aggregate amount not in excess of $10,000,000, or the lien of any
         judgment or attachment the execution or enforcement of which has been
         stayed or which has been appealed and secured, if necessary, by the
         filing of an appeal bond;

                  (viii) any mortgage, pledge, lien or encumbrance on any
         property held or used by the Issuer or the Guarantor, as the case may
         be, or any Subsidiary of it in connection with the exploration for,
         development of or production of oil, gas, natural gas (including
         liquified gas and storage gas), other hydrocarbons, helium, coal,
         metals, minerals, steam, timber, geothermal or other natural resources
         or synthetic fuels, such properties to include, but not be limited to,
         the interest of the Issuer or the Guarantor, as the case may be, or
         such Subsidiary in any mineral fee interests, oil, gas or other mineral
         leases, royalty, overriding royalty or net profits interests,
         production payments and other similar interests, wellhead production
         equipment, tanks, field gathering lines, leasehold or field separation
         and processing facilities, compression facilities and other similar
         personal property and fixtures;

                  (ix) any mortgage, pledge, lien or encumbrance on oil, gas,
         natural gas (including liquified gas and storage gas), and other
         hydrocarbons, helium, coal, metals, minerals, steam, timber, geothermal
         or other natural resources or synthetic fuels produced or recovered
         from any property, an interest in which is owned or lease by the Issuer
         or the Guarantor, as the case may be, or any Subsidiary of it;

                  (x) mortgages, pledges, liens or encumbrances upon any
         property heretofore or hereafter acquired, created at the time of
         acquisition or within 365 days thereafter to secure all or a portion of
         the purchase price thereof, or existing thereon at the date of
         acquisition, whether or not assumed by the Issuer or the Guarantor, as
         the case may be, or any Subsidiary of it, provided that every such
         mortgage, pledge, lien or encumbrance shall apply only to the property
         so acquired and fixed improvements thereon;

                  (xi) any extension, renewal or refunding, in whole or in part,
         of any mortgage, pledge, lien or encumbrance permitted by Section (x)
         above, if limited to the same property or any portion thereof subject
         to, and securing not more than the amount secured by, the mortgage,
         pledge, lien or encumbrance extended, renewed or refunded;

                  (xii) mortgages, pledges, liens or encumbrances upon any
         property heretofore or hereafter acquired by any corporation that is or
         becomes such a Subsidiary of the Issuer or the Guarantor, as the case
         may be, after the date of the Fiscal Agency Agreement ("Acquired
         Entity"), provided that every such mortgage, pledge, lien or
         encumbrance (1) shall either (a) exist prior to the time the Acquired
         Entity becomes such a Subsidiary or (b) be created at the time the
         Acquired Entity becomes such a Subsidiary or within 365 days thereafter
         to secure all or a portion of the acquisition price thereof and (2)
         shall only apply to those properties owned by the Acquired Entity at
         the time it becomes such a Subsidiary or thereafter acquired by it from
         sources other than the Issuer or the Guarantor, as the case may be, or
         any other Subsidiary of it;

                  (xiii) the pledge of current assets, in the ordinary course of
         business, to secure current liabilities;

                                      A-7

<PAGE>

                  (xiv) mechanics' or materialmen's liens, any liens or charges
         arising by reason of pledges or deposits to secure payment of workmen's
         compensation or other insurance, good faith deposits in connection with
         tenders, leases of real estate, bids or contracts (other than contracts
         for the payment of money), deposits to secure duties or public or
         statutory obligations, deposits to secure, or in lieu of, surety, stay
         or appeal bonds, and deposits as security for the payment of taxes or
         assessments or similar charges;

                  (xv) any lien arising by reason of deposits with, or the
         giving of any form of security to, any governmental agency or any body
         created or approved by law or governmental regulation for any purpose
         at any time in connection with the financing of the acquisition or
         construction of property to be used in the business of the Issuer or
         the Guarantor, as the case may be, or any Subsidiary of it or as
         required by law or governmental regulation as a condition to the
         transaction of any business or the exercise of any privilege or
         license, or to enable the Issuer or the Guarantor, as the case may be,
         or any such Subsidiary to maintain self-insurance or to participate in
         any funds established to cover any insurance risks or in connection
         with workmen's compensation, unemployment insurance, old age pensions
         or other social security, or to share in the privileges or benefits
         required for companies participating in such arrangements;

                  (xvi) any lien to secure Indebtedness of the Issuer or the
         Guarantor, as the case may be, other than Funded Dent (as hereinafter
         defined);

                  (xvii) any mortgage, pledge, lien or encumbrance of or upon
         any office equipment, data processing equipment (including, without
         limitation, computer and computer peripheral equipment), or
         transportation equipment (including without limitation, motor vehicles,
         tractors, trailers, marine vessels, barges, towboats, rolling stock and
         aircraft);

                  (xviii) any mortgage, pledge, lien or encumbrance created or
         assumed by the Issuer or the Guarantor, as the case may be, or any
         Subsidiary of it in connection with the issuance of debt securities the
         interest on which is excludable from gross income of the holder of such
         security pursuant to the Internal Revenue Code of 1986, as amended, for
         the purpose of financing, in whole or in part, the acquisition or
         construction of property to be used by the Issuer or the Guarantor, as
         the case may be, or any such Subsidiary; or

                  (xix) the pledge or assignment of accounts receivable, or the
         pledge or assignment of conditional sales contracts or chattel
         mortgages and evidences of indebtedness secured thereby, received in
         connection with the sale by the Issuer or the Guarantor, as the case
         may be, or any Subsidiary of it of goods or merchandise to customers of
         the Issuer, the Guarantor or any Subsidiary.

                  In case the Issuer or the Guarantor, as the case may be, or
any Subsidiary of it shall propose to pledge, mortgage or hypothecate any
Principal Property at any time owned by it to secure any of its Indebtedness,
other than as permitted by subdivisions (i) to (xix), inclusive, of this
Paragraph 7, the Issuer or the Guarantor, as the case may be, will prior thereto
give written notice thereof to the Fiscal Agent, and the Issuer will, or will
cause such Subsidiary to, prior to or simultaneously with such pledge, mortgage
or hypothecation, effectively secure all the Securities equally and ratably with
such Indebtedness or the Guarantor will, or will cause such Subsidiary to, prior
to or simultaneously with such pledge, mortgage or hypothecation, effectively
secure all the Guarantees equally and ratably with such Indebtedness.

                  Notwithstanding the foregoing provisions of this Paragraph 7,
the Issuer or the Guarantor, as the case may be, or any Subsidiary of it may
issue, assume or guarantee Indebtedness secured by a mortgage which would
otherwise be subject to the foregoing restrictions in an aggregate amount which,
together with all other Indebtedness of the Issuer or the Guarantor, as the case
may be, or a Subsidiary of it secured by a mortgage which (if originally issued,
assumed or guaranteed at such time) would otherwise be subject to the foregoing
restrictions (not including Indebtedness permitted to be secured under clauses
(i) through (xix) above), does not at the time exceed 10% of the Consolidated
Net Tangible Assets of the Issuer or the Guarantor, as the case may be, as shown
on its audited consolidated financial statements as of the end of the fiscal
year preceding the date of determination.

                                      A-8

<PAGE>

                  For purposes of the Securities,

                  "Consolidated Net Tangible Assets" of any corporation means
total assets less (a) total current liabilities (excluding indebtedness due
within 365 days) and (b) goodwill, patents and trademarks, all as reflected in
such corporation's audited consolidated balance sheet preceding the date of a
determination under the immediately preceding paragraph of this Paragraph 7.

                  "Funded Debt" as applied to any corporation means all
Indebtedness incurred, created, assumed or guaranteed by such corporation, or
upon which it customarily pays interest charges, which matures, or is renewable
by such corporation to a date, more than one year after the date as of which
Funded Debt is being determined; provided, however, that the term "Funded Debt"
shall not include (i) Indebtedness incurred in the ordinary course of business
representing borrowings, regardless of when payable, of such Corporation from
time to time against, but not in excess of the face amount of, its installment
accounts receivable for the sale of appliances and equipment sold in the regular
course of business or (ii) advances for construction and security deposits
received by such corporation in the ordinary course of business.

                  "Indebtedness" as applied to any corporation, shall mean
bonds, debentures, notes and other instruments representing obligations created
or assumed by any such corporation for the repayment of money borrowed (other
than unamortized debt discount or premium). All Indebtedness secured by a lien
upon property owned by any corporation and upon which Indebtedness any such
corporation customarily pays interest, although any such corporation has not
assumed or become liable for the payment of such Indebtedness, shall for all
purposes of the Securities and Guarantees be deemed to be Indebtedness of any
such corporation. All Indebtedness for money borrowed incurred by other persons
which is directly guaranteed as to payment of principal by any corporation shall
for all purposes of the Securities and Guarantees be deemed to be Indebtedness
of such corporation, but no other contingent obligation of such corporation in
respect of Indebtedness incurred by other persons shall for any purpose be
deemed Indebtedness of such corporation. Indebtedness of any corporation shall
not include: (i) amounts which are payable only out of all or a portion of the
oil, gas, natural gas, helium, coal, metals, minerals, steam, timber,
hydrocarbons, or geothermal or other natural resources produced, derived, or
extracted from properties owned or developed by such corporation; (ii) any
amount representing capitalized lease obligations; (iii) any indebtedness
incurred to finance oil, gas, natural gas, helium, coal, metal, mineral, steam,
timber, hydrocarbons, or geothermal or other natural resources or synthetic fuel
exploration or development, payable with respect to principal and interest,
solely out of the proceeds of oil, gas, natural gas, helium, coal, metals,
minerals, steam, timber, hydrocarbons, or geothermal or other natural resources
or synthetic fuel to be produced, sold, and/or delivered by any such
corporation; (iv) indirect guarantees or other contingent obligations in
connection with the Indebtedness of others, including agreements, contingent or
otherwise, with such other persons or with third persons with respect to, or to
permit or ensure the payment of, obligations of such other persons, including,
without limitation, agreements to purchase or repurchase obligations of such
other persons, agreements to advance or supply funds to or to invest in such
other persons, or agreements to pay for property, products, or services of such
other persons (whether or not conferred, delivered or rendered), and any demand
charge, throughput, take-or-pay, keep-well, make-whole, cash deficiency,
maintenance of working capital or earnings or similar agreements; and (v) any
guarantees with respect to lease or other similar periodic payments to be made
by other persons.

                  "Principal Property" of the Issuer or the Guarantor, as the
case may be, means any oil or gas pipeline, gas processing plant or chemical
plant located in the United States, except any such pipeline, facility, station
or plant that in the opinion of the Board of Directors of the Issuer or the
Guarantor, as the case may be, is not of material importance to the total
business conducted by the Issuer or the Guarantor, as the case may be, or its
Subsidiaries. "Principal Property" shall not include any oil or gas property,
the production or any proceeds of production from an oil or gas producing
property or the production or any proceeds of production of gas processing
plants or oil or gas or petroleum products in any pipeline. With respect to the
Issuer only, "Principal Property" shall also include any gas storage facility or
gas compressor station located in the United States, except any such facility or
station that in the opinion of the Board of Directors of the Issuer is not of
material importance to the total business conducted by the Issuer or its
Subsidiaries, and "Principal Property" shall not include any liquified natural
gas plants and related storage facilities or any natural gas liquids processing
plants.

                                      A-9

<PAGE>

          8.    (a) Neither the Issuer nor the Guarantor shall consolidate with
or merge into any other person or convey, transfer or lease its properties and
assets substantially as an entirety to any person, and neither the Issuer
nor the Guarantor shall permit any person to consolidate with or merge into the
Issuer or the Guarantor, respectively, or convey, transfer or lease its
properties and assets substantially as an entirety to the Issuer or Guarantor,
respectively, unless:

                           (i) in case the Issuer or the Guarantor shall
         consolidate with or merge into another person or convey, transfer or
         lease its properties and assets substantially as an entirety to any
         person, the person formed by such consolidation or into which the
         Issuer or the Guarantor, respectively, is merged or the person which
         acquires by conveyance or transfer, or which leases, the properties and
         assets of the Issuer or the Guarantor, respectively, substantially as
         an entirety shall be a corporation, partnership or trust, shall be
         organized and validly existing under the laws of the United States of
         America, any State thereof or the District of Columbia (the "Successor
         Person") and shall expressly assume, by amendment to the Fiscal Agency
         Agreement signed by the Issuer, the Guarantor and such Successor Person
         and delivered to the Fiscal Agent, (x) in the case of the Issuer, the
         due and punctual payment of the principal of and interest on all the
         Securities and the performance or observance of every covenant hereof
         and of the Fiscal Agency Agreement on the part of the Issuer to be
         performed or observed or, (y) in the case of the Guarantor, the
         Guarantees endorsed on all the Securities and the performance or
         observance of every covenant thereof and of the Fiscal Agency Agreement
         on the part of the Guarantor to be performed or observed;

                           (ii) immediately after giving effect to such
         transaction and treating any indebtedness which becomes an obligation
         of the Issuer or the Guarantor, respectively, or any Subsidiary of it
         as a result of such transaction as having been incurred by the Issuer
         or the Guarantor, respectively, or any such Subsidiary at the time of
         such transaction, no event of default (as set forth in Paragraph 6),
         and no event which, with notice or lapse of time or both, would become
         such an event of default, shall have happened and be continuing;

                           (iii) if, as a result of any such consolidation or
         merger or such conveyance, transfer or lease, properties or assets of
         the Issuer or the Guarantor, respectively, or any Subsidiary of it
         would become subject to a mortgage, pledge, lien, security interest or
         other encumbrance which would not be permitted by Paragraph 7 hereof,
         the Issuer or the Guarantor, respectively, or the Successor Person, as
         the case may be, shall take such steps as shall be necessary
         effectively to secure the Securities or the Guarantees endorsed
         thereon, respectively, equally and ratably with (or prior to) all
         Indebtedness secured by such mortgage, pledge, lien, security interest
         or other encumbrance; and

                           (iv) the Issuer or the Guarantor, respectively, has
         delivered to the Fiscal Agent an Officers' Certificate and a written
         opinion or opinions of counsel satisfactory to the Fiscal Agent (who
         may be counsel to the Issuer or the Guarantor), stating that such
         consolidation, merger, conveyance, transfer or lease and such amendment
         to the Fiscal Agency Agreement comply with this Paragraph 8 and that
         all conditions precedent herein provided for relating to such
         transaction have been complied with.

                (b) Upon any such consolidation or merger, or any conveyance,
transfer or lease of the properties and assets of the Issuer or the Guarantor,
respectively, substantially as an entirety in accordance with paragraph 8(a),
the Successor Person shall succeed to, and be substituted for, and may exercise
every right and power of, the Issuer or the Guarantor, respectively, under the
Fiscal Agency Agreement and the Securities or the Guarantees endorsed thereon,
respectively, with the same effect as if the Successor Person had been named as
the Issuer or the Guarantor, respectively, in the Fiscal Agency Agreement and
the Securities or Guarantees endorsed thereon, respectively, and thereafter the
Issuer or the Guarantor, respectively, except in the case of a lease of its
properties and assets, shall be released from its liability as obligor on any of
the Securities or the Guarantees endorsed thereon, respectively, and under the
Fiscal Agency Agreement.

                                      A-10

<PAGE>

         9. Section 7 of the Fiscal Agency Agreement, which requires the Issuer
and the Guarantor to provide registered holders of Securities or, in the case of
clauses (a) and (b) thereof, designated prospective purchasers of Securities
with certain information and an Officers' Certificate, is hereby incorporated
mutatis mutandis by reference herein.

         10. Until the date that is three years from the date of original
issuance of the Securities, the Issuer and the Guarantor will not, and will not
permit any of their "affiliates" (as defined under Rule 144 under the Act or any
successor provision thereto) to, resell any Securities which constitute
"restricted securities" under Rule 144 that have been reacquired by any of them.

         11. If any mutilated Security is surrendered to the Fiscal Agent, the
Issuer shall execute, and the Fiscal Agent shall authenticate and deliver in
exchange therefor, a new Security with a Guarantee endorsed thereon of like
tenor and principal amount, bearing a number not contemporaneously outstanding.

         If there be delivered to the Issuer, the Guarantor and the Fiscal Agent
(i) evidence to their satisfaction of the destruction, loss or theft of any
Security or related Guarantee and (ii) such security or indemnity as may be
required by them to save each of them and any agent of each of them harmless,
then, in the absence of notice to the Issuer, the Guarantor or the Fiscal Agent
that such Security has been acquired by a bona fide purchaser, the Issuer shall
execute, and upon its request the Fiscal Agent shall authenticate and deliver in
lieu of any such destroyed, lost or stolen Security a new Security with a
Guarantee endorsed thereon of like tenor and principal amount and bearing a
number not contemporaneously outstanding.

         Upon the issuance of any new Security with a Guarantee endorsed thereon
under this Paragraph, the Issuer may require the payment of a sum sufficient to
cover any tax or other governmental charge that may be imposed in relation
thereto and any other expenses (including the fees and the expenses of the
Fiscal Agent) connected therewith.

         Every new Security issued pursuant to this Paragraph in lieu of any
destroyed, lost or stolen Security, shall constitute an original additional
contractual obligation of the Issuer guaranteed by the Guarantor, whether or not
the destroyed, lost or stolen Security shall be at any time enforceable by
anyone.

         Any new Security delivered pursuant to this Paragraph shall be so dated
that neither gain nor loss in interest shall result from such exchange.

         The provisions of this Paragraph 11 are exclusive and shall preclude
(to the extent lawful) all other rights and remedies with respect to the
replacement or payment of mutilated, destroyed, lost or stolen Securities and
related Guarantees.

          12. Section 11 of the Fiscal Agency Agreement, which subject to
certain conditions permits the Guarantor at its election to assume, in whole
but not in part, the obligations of the Issuer under the Securities and the
Fiscal Agency Agreement, at any time on or after November 12, 1993, and provides
that upon such assumption the Issuer shall be released from such obligations, is
hereby incorporated mutatis mutandis by reference herein.

                                      A-11

<PAGE>

         13. Section 12 of the Fiscal Agency Agreement, which Section is hereby
incorporated mutatis mutandis by reference herein, provides that, with certain
exceptions as therein provided and by written consent of a majority in the
principal amount of all Outstanding Securities, the Issuer, the Guarantor and
the Fiscal Agent may modify, amend or supplement the Fiscal Agency Agreement
or the terms of the Securities or Guarantee or may give consents or waivers or
take other actions with respect thereto. Any such modification, amendment,
supplement, consent, waiver or other action shall be conclusive and binding on
the holder of this Security and on all future holders of this Security and of
any Security issued upon the registration of transfer hereof or in exchange
heretofore or in lieu hereof, whether or not notation thereof is made upon this
Security. The Fiscal Agency Agreement and the terms of the Securities and
Guarantees may be modified or amended by the Issuer, the Guarantor and the
Fiscal Agent, without the consent of any holders of Securities, for the purpose
of (i) adding to the covenants of the Issuer or the Guarantor for the benefit of
the holders of Securities; or (ii) surrendering any right or power conferred
upon the Issuer or the Guarantor, or (iii) securing the Securities or the
Guarantees pursuant to the requirements of the Securities or the Guarantees or
otherwise, or (iv) evidencing the succession of another corporation to the
Issuer or the Guarantor and the assumption by any such successor of the
covenants and obligations of the Issuer or the Guarantor in the Securities or
the Guarantees, respectively, or in the Fiscal Agency Agreement pursuant to
Paragraph 8 hereof, or (v) evidencing the assumption by the Guarantor of the
covenants and obligations of the Issuer in the Securities and the Fiscal Agency
Agreement pursuant to Paragraph 12 hereof, or (vi) correcting or supplementing
any defective provision contained in the Securities, the Guarantees or in the
Fiscal Agency Agreement, to all of which each holder of any Security, by
acceptance thereof, consents.

         14. No reference herein to the Fiscal Agency Agreement and no provision
of this Security or of the Fiscal Agency Agreement shall alter or impair the
obligation of the Issuer, which is absolute and unconditional, to pay the
principal of and interest on this Security at the times, place and rate, and
in the coin or currency, herein prescribed.

         15. This Security is subject to the provisions of Section 15 of the
Fiscal Agency Agreement (which are incorporated mutatis mutandis by reference
herein) which provide for the defeasance at any time of (i) the entire indebted-
ness of this Security or (ii) certain covenants and events of default, in each
case upon compliance with certain conditions set forth therein.

         16. THIS SECURITY SHALL BE GOVERNED BY AND CONSTRUED IN ACCORDANCE WITH
THE LAWS OF THE STATE OF NEW YORK.

                                      A-12
<PAGE>

                                    EXHIBIT B

                                FORM OF GUARANTEE

         FOR VALUE RECEIVED, Enron Corp., a corporation duly organized under the
laws of the State of Delaware (the "Guarantor"), hereby unconditionally
guarantees to the holder of the Security upon which this Guarantee is endorsed
the due and punctual payment of the principal or and interest on such Security,
when and as the same shall become due and payable, whether at maturity, upon
acceleration, or otherwise, according to the terms thereof and of the Fiscal
Agency Agreement referred to therein. In case of the failure of Northern Natural
Gas Company or any successor thereto (the "Issuer") punctually to pay any such
principal or interest, the Guarantor hereby agrees to cause any such payment to
be made punctually when and as the same shall become due and payable, whether at
maturity, upon acceleration or otherwise, and as if such payment were made by
the Issuer.

         The Guarantor hereby agrees that its obligations hereunder shall be as
if it were as principal and not merely as surety, and shall be absolute and
unconditional, irrespective of, and shall be unaffected by, any invalidity,
irregularity or unenforceability of said Security or said Fiscal Agency
Agreement, any failure to enforce the provisions of said Security or said Fiscal
Agency Agreement, or any waiver, modification or indulgence granted to the
Issuer with respect thereto, by the holder of said Security or the Fiscal Agent
under said Fiscal Agency Agreement, the recovery of any judgment against the
Issuer or any action to enforce the same or any other circumstances which may
otherwise constitute a legal or equitable discharge of a surety or guarantor.
The Guarantor hereby waives diligence, presentment, demand of payment, filing of
claims with a court in the event of merger, insolvency, or bankruptcy of the
Issuer, any right to require a proceeding first against the Issuer, protest or
notice with respect to said Security or the indebtedness evidenced thereby and
all demands whatsoever, and covenants that this Guarantee will not be discharged
except by payment in full of the principal and interest in respect of said
Security and the complete performance of all other obligations contained in said
Security.

         The Guarantor shall be subrogated to all rights of the holder of said
Security against the Issuer in respect of any amounts paid to such holder by the
Guarantor pursuant to the provisions of this Guarantee; provided, however, that
the Guarantor shall not be entitled to enforce, or to receive any payment
arising out of or based upon, such right of subrogation until the principal of
and interest on all the Securities (as defined in said Security) shall have been
paid in full.

         No reference herein to said Fiscal Agency Agreement and no provision of
this Guarantee or of said Fiscal Agency Agreement shall alter or impair the
guarantee of the Guarantor, which is absolute and unconditional, of the due and
punctual payment of the principal of and interest on the Security upon which
this Guarantee is endorsed.

         The Guarantor hereby agrees to observe the provisions of said Security
that by their terms are applicable to it, including without limitation those of
Paragraph 7 of said Security. This Guarantee is subject to the provisions of
Section 15 of the Fiscal Agency Agreement (which are incorporated mutatis
mutandis by reference herein) which provide for the defeasance at any time of
(i) the entire indebtedness of this Guarantee or (ii) certain covenants and
events of default, in each case upon compliance with certain conditions set
forth therein.

         This Guarantee shall not be valid or obligatory for any purpose until
the certificate of authentication of said Security shall have been manually
executed by or on behalf of the Fiscal Agent under said Fiscal Agency Agreement.

         THIS GUARANTEE SHALL BE DEEMED TO BE A CONTRACT MADE UNDER THE LAWS OF
THE STATE OF NEW YORK, AND FOR ALL PURPOSES SHALL BE GOVERNED BY AND CONSTRUED
IN ACCORDANCE WITH THE LAWS OF THE STATE OF NEW YORK.

                                      B-1

<PAGE>

         IN WITNESS WHEREOF, the Guarantor has caused this instrument to be duly
executed in facsimile and its corporate seal to be affixed hereto.

                                            ENRON CORP.

                                            By: _______________________________
                                                     Chairman of the Board

Dated:        May 11, 1993

[Corporate Seal]

Attest:

____________________________
Vice President and Secretary

                                      B-2EXHIBIT 10.69

                            FISCAL AGENCY AGREEMENT

                                     Between

                          NORTHERN NATURAL GAS COMPANY,
                                     Issuer

                                       and

                   CHASE BANK OF TEXAS, NATIONAL ASSOCIATION,
                                  Fiscal Agent

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

                          Dated as of September 4, 1998

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

                    6.75% Senior Notes due September 15, 2008

<PAGE>

                                TABLE OF CONTENTS

                                                                          Page

RECITALS OF THE ISSUER                                                       1

1. The Securities                                                            1
           (a) General                                                       1
           (b) Form of Securities; Denominations of Securities               1
           (c) Temporary Securities                                          1
           (d) Legends                                                       2
           (e) Book-Entry Provisions                                         2
2. Fiscal Agent; Other Agents                                                2
3. Authentication                                                            3
4. Payment and Cancellation                                                  3
           (a) Payment                                                       4
           (b) Cancellation                                                  4
5. Exchange of Securities                                                    4
6. Register; Record Date for Certain Actions                                 4
7. Delivery of Certain Information                                           5
           (a) Non-Reporting Issuer                                          6
           (b) Information After Three Years                                 6
           (c) Periodic Reports                                              6
8. Conditions of Fiscal Agent's Obligations                                  7
           (a) Compensation and Indemnity                                    7
           (b) Agency                                                        7
           (c) Advice of Counsel                                             7
           (d) Reliance                                                      7
           (e) Interest in Securities, etc.                                  7
           (f) Certifications                                                7
           (g) No Implied Obligations                                         8
           (h) No Liability                                                   8
           (i) No Inquiry                                                     8
           (j) Agents                                                         8
9. Resignation and Appointment of Successor                                   8
           (a) Fiscal Agent and Paying Agent                                  8
           (b) Resignation                                                    8
           (c) Successors                                                     9
           (d) Acknowledgment                                                 9
           (e) Merger, Consolidation, etc.                                    9
10. Payment of Taxes                                                          9
11. Amendments                                                                9
           (a) Approval                                                      10
           (b) Binding Nature of Amendments, Notice, Notations, etc.         10
           (c) "Outstanding" Defined                                         10
12. GOVERNING LAW                                                            11
13. Notices                                                                  11
14. Defeasance (Legal and Covenant)                                          11
           (a) Issuer's Option to Effect Defeasance or Covenant Defeasance   11
           (b) Defeasance and Discharge                                      11
<PAGE>

           (c) Covenant Defeasance                                           12
           (d) Conditions to Defeasance and Covenant Defeasance              12
           (e) Deposit in Trust; Miscellaneous                               13
           (f) Reinstatement                                                 14
15. Headings                                                                 14
16. Counterparts                                                             14
17. Successors and Assigns                                                   14
18. Separability Clause                                                      14

EXHIBIT A - FORM OF SECURITY

<PAGE>

         FISCAL AGENCY AGREEMENT ("Agreement"), dated as of September 4, 1998,
between NORTHERN NATURAL GAS COMPANY, a corporation duly organized under the
laws of the State of Delaware (the "Issuer"), and CHASE BANK OF TEXAS, NATIONAL
ASSOCIATION, a national banking association duly organized and existing under
the laws of the United States of America, as Fiscal Agent.

                             RECITALS OF THE ISSUER

         The Issuer has duly authorized the creation of an issue of its 6.75%
Senior Notes due September 15, 2008 (herein called the "Securities") of
substantially the tenor and amount hereinafter set forth, and to provide
therefor the Issuer has duly authorized the execution and delivery of this
Agreement.

         All things necessary to make the Securities, when executed by the
Issuer and authenticated and delivered hereunder and duly issued by the Issuer,
the valid obligations of the Issuer, and to make this Agreement a valid
agreement of the Issuer, in accordance with their and its terms, have been done.

         1. The Securities.

                  (a)   General. The aggregate principal amount of Securities
which may be authenticated and delivered under this Agreement is limited to
$150,000,000 except for Securities authenticated and delivered upon registration
of transfer, or in exchange for, or in lieu of other Securities pursuant to the
provisions of this Agreement or the Securities.

                  The Securities shall be known and designated as the 6.75%
Senior Notes due September 15, 2008 of the Issuer. The Securities will be
unsecured, direct, unconditional and general obligations of the Issuer and will
rank pari passu with all other unsecured and unsubordinated indebtedness of the
Issuer.

                  (b)   Form of Securities: Denominations of Securities. The
Securities will be issued in registered form without coupons in substantially
the form of Exhibit A hereto and in minimum denominations of $100,000 and in
integral multiples of $1,000 in excess of $100,000. The Securities shall be
executed manually or in facsimile on behalf of the Issuer by its Chairman of the
Board, President or a Vice President and by its Secretary or an Assistant
Secretary (the "Authorized Officers"), notwithstanding that such officers, or
any of them, shall have ceased, for any reason, to hold such offices prior to
the authentication and delivery of such Securities or did not hold such offices
at the date of such Securities. The Securities may also have such additional
provisions, omissions, variations or substitutions as are not inconsistent with
the provisions of this Agreement and may have such letters, numbers or other
marks of identification and such legends or endorsements placed thereon as may
be required to comply with any law or with any rules made pursuant thereto or
with the rules of any securities exchange or governmental agency or as may,
consistently herewith, be determined by the Authorized Officers of the Issuer
executing such Securities, as conclusively evidenced by their execution of such
Securities. All of the Securities shall be otherwise substantially identical
except as to denominations of Securities and as provided herein.

                  (c)   Temporary Securities. Until definitive Securities are
prepared, the Issuer may execute, and there shall be authenticated and delivered
in accordance with the provisions of Section 3 hereof (in lieu of definitive
printed Securities), temporary Securities. Such temporary Securities may be in
registered global form. Such temporary Securities shall be subject to the same
limitations and conditions and entitled to the same rights and benefits as
definitive Securities, except as provided herein or therein. Temporary
Securities shall be exchangeable for definitive Securities, when such definitive
Securities are available for delivery; and upon the surrender for exchange of
such temporary Securities, the Issuer shall execute and there shall be
authenticated and delivered, in accordance with the provisions of Sections 5 and
6 hereof, in exchange for such temporary Securities, a like aggregate principal
amount of definitive Securities of like tenor. The Issuer shall pay all charges,
including (without limitation) stamp and other taxes and governmental charges,
incident to any exchange of temporary Securities for definitive Securities. All
temporary Securities shall be identified as such and shall describe the right of
the holder thereof to effect an exchange for definitive Securities and the
manner in which such an exchange may be effected.

                                      -1-

<PAGE>

                  (d)   Legends. Securities shall be stamped or otherwise be
imprinted with the legends set forth on the face of the text of the Securities
attached as Exhibit A hereto and any legend pursuant to Section 1(d) or 1(e)
hereof. The legends so provided on the face of the text of the Securities may be
removed from any Security, upon written order signed in the name of the Issuer
by its Chairman of the Board, President or a Vice President and by its Secretary
or an Assistant Secretary and delivered to the Fiscal Agent ("Order"), (i) two
years from the later of issuance of the Security or the date such Security (or
any predecessor) was last acquired from an "affiliate" of the Issuer within the
meaning of Rule 144 under the Securities Act of 1933, as amended, (the "Act") or
(ii) in connection with a sale made pursuant to the volume (and other
restrictions) of Rule 144 under the Act following one year from such time,
provided that, if the legend is removed and the Security is subsequently held by
such an affiliate of the Issuer, the legend shall be reinstated. Any legends
provided pursuant to Sections 1(d) and (e) hereof may be removed as provided in
such Sections.

                  (e)   Book-Entry Provisions. This Section 1(e) shall apply
only to global Securities deposited with or on behalf of a depository located in
the United States (a "U.S. Depository").

                  The Securities will be issued initially in the form of one or
more registered global Securities deposited with or on behalf of a U.S.
Depository, that (i) shall be registered in the name of the U.S. Depository for
such global Security or Securities or the nominee of such U.S. Depository, (ii)
shall be delivered by the Fiscal Agent to such U.S. Depository or pursuant to
such U.S. Depository's instruction and (iii) shall bear a legend substantially
to the following effect: "Unless this certificate is presented by an authorized
representative of [insert name and address of Depository] to the issuer or its
agent for registration of transfer, exchange or payment, and any certificate
issued is registered in the name of [insert name of nominee of Depository], or
such other name as is requested by an authorized representative of [insert name
of Depository], and any payment hereon is made to [insert name of nominee of
Depository], ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY
OR TO ANY PERSON IS WRONGFUL, since the registered owner hereof, [insert name of
nominee of Depository], has an interest herein."

                  Members of, or participants in, a U.S. Depository ("Agent
Members") shall have no rights under this Agreement with respect to any global
Security held on their behalf by a U.S. Depository or under the global Security,
and such U.S. Depository may be treated by the Issuer, the Fiscal Agent, and any
agent of the Issuer, or the Fiscal Agent as the owner of such global Security
for all purposes whatsoever. Notwithstanding the foregoing, nothing herein shall
prevent the Issuer, the Fiscal Agent, or any agent of the Issuer, or the Fiscal
Agent, from giving effect to any written certification, proxy or other
authorization furnished by a U.S. Depository or impair, as between a U.S.
Depository and its Agent Members, the operation of customary practices governing
the exercise of the rights of a holder of any Security.

                  So long as the U.S. Depository is the registered owner of
Securities, the U.S. Depository will for all purposes of the Securities and this
Agreement be considered the sole owner or holder of such Securities. Until such
time as definitive Securities may be issued, beneficial owners of Securities
will not be entitled to have Securities registered in their names, will not
receive or be entitled to receive physical delivery of Securities in definitive
form, and will not be considered the owners or holders thereof under this
Agreement for any purpose.

                  If (i) the Issuer notifies the Fiscal Agent in writing that
the U.S. Depository is no longer willing or able to act as a depository and the
Issuer is unable to locate a qualified successor within 90 days or (ii) the
Issuer, at its option, notifies the Fiscal Agent in writing that it elects to
cause the issuance of Securities in definitive form, then, upon surrender by the
global Security holder of its global Security, Securities in such form will be
issued to each person that such global Security holder and the U.S. Depository
identifies as the beneficial owner of the related Securities. Upon such
issuance, the Fiscal Agent shall register such Securities in the name of, and
cause the same to be delivered to, such person or persons (or the nominee
thereof).

2.       Fiscal Agent:  Other Agents.

                                      -2-
<PAGE>

         The Issuer hereby appoints Chase Bank of Texas, National Association
acting through its corporate trust office in Houston, Texas as fiscal agent of
the Issuer in respect of the Securities, upon the terms and subject to the
conditions herein set forth, and Chase Bank of Texas, National Association
hereby accepts such appointment. Chase Bank of Texas, National Association and
any successor or successors as such fiscal agent qualified and appointed in
accordance with Section 9 hereof are herein called the "Fiscal Agent." The
Fiscal Agent shall have the powers and authority granted to and conferred upon
it in the Securities and hereby and such further powers and authority to act on
behalf of the Issuer as may be mutually agreed upon by the Issuer and the Fiscal
Agent. All of the terms and provisions with respect to such powers and authority
contained in the Securities are subject to and governed by the terms and
provisions hereof.

         The Issuer may appoint one or more agents (a "Paying Agent" or "Paying
Agents") for the payment (subject to applicable laws and regulations) of the
principal of and interest on the Securities, and one or more agents (a "Transfer
Agent" or "Transfer Agents") for the transfer and exchange of Securities, at
such place or places as the Issuer may determine; provided, however, the Issuer
shall at all times maintain a Paying Agent or agent thereof and Transfer Agent
or agent thereof in the Borough of Manhattan, The City of New York (which Paying
Agent and Transfer Agent may be the Fiscal Agent or any of its affiliates). The
Issuer initially appoints the Fiscal Agent as Paying Agent and Transfer Agent.
The Issuer shall promptly notify the Fiscal Agent of the name and address of
each Paying Agent and Transfer Agent appointed, and will notify the Fiscal Agent
of the resignation or termination of any Paying Agent or Transfer Agent. Subject
to the provisions of Section 9(c) hereof, the Issuer may vary or terminate the
appointment of any such Paying Agent or Transfer Agent at any time and from time
to time upon giving not less than 90 days' notice to such Paying Agent or
Transfer Agent, as the case may be, and to the Fiscal Agent.

         The Issuer shall cause notice of any resignation, termination or
appointment of any Paying Agent or Transfer Agent or of the Fiscal Agent and of
any change in the office through which any such Agent will act to be given as
provided in the text of the Securities.

3.       Authentication.

         The Fiscal Agent is authorized, upon receipt of Securities duly
executed on behalf of the Issuer for the purposes of the original issuance of
the Securities, (i) to authenticate said Securities in an aggregate principal
amount not in excess of $150,000,000 and to deliver said Securities in
accordance with an Order or Orders and (ii) thereafter to authenticate and
deliver said Securities in accordance with the provisions hereinafter set forth.

         The Fiscal Agent may, with the consent of the Issuer, appoint by an
instrument or instruments in writing one or more agents (which may include
itself) for the authentication of Securities and, with such consent, vary or
terminate any such appointment upon written notice and approve any change in the
office through which any authenticating agent acts. The Issuer (by written
notice to the Fiscal Agent and the authenticating agent whose appointment is to
be terminated) may also terminate any such appointment at any time. The Fiscal
Agent hereby agrees to solicit written acceptances from the entities concerned
(in form and substance satisfactory to the Issuer) of such appointments. In its
acceptance of such appointment, each such authenticating agent shall agree to
act as an authenticating agent pursuant to the terms and conditions of this
Agreement.

4.      Payment and Cancellation.

                                      -3-
<PAGE>

                  (a)   Payment. Subject to the following provisions, the
Issuer shall provide to the Fiscal Agent in funds available on or prior to each
date on which a payment of principal of or any interest on the Securities shall
become due, as set forth in the text of the Securities, such amount, in such
coin or currency, as is necessary to make such payment, and the Issuer hereby
authorizes and directs the Fiscal Agent from funds so provided to it to make or
cause to be made payment of the principal of and interest, as the case may be,
on the Securities set forth herein and in the text of the Securities. The Fiscal
Agent shall arrange directly with any Paying Agent who may have been appointed
pursuant to the provisions of Section 2 hereof for the payment from funds so
paid by the Issuer of the principal of and interest on the Securities as set
forth herein and in the text of the Securities. Notwithstanding the foregoing,
the Issuer may provide directly to a Paying Agent funds for the payment of the
principal thereof and premium and interest, if any, payable thereon under an
agreement with respect to such funds containing substantially the same terms and
conditions set forth in this Section 4(a) and in Section 8(b) hereof; and the
Fiscal Agent shall have no responsibility with respect to any funds so provided
by the Issuer to any such Paying Agent.

                  Any interest on the Securities shall be paid, unless otherwise
provided in the text of the Securities, to the persons (the "registered owners")
in whose names such Securities are registered on the register maintained
pursuant to Section 6 hereof at the close of business on the record dates
designated in the text of the Securities. Payments of principal of Securities
shall be payable against surrender thereof at the corporate trust office or
office of an agent of the Fiscal Agent and at the offices of such other Paying
Agents as shall have been appointed pursuant to Section 2 hereof. Payments of
principal shall be made against surrender of Securities, and payments of
interest on Securities shall be made, in accordance with the foregoing and
subject to applicable laws and regulations, by check mailed on or before the due
date for such payment to the person entitled thereto at such person's address
appearing on the register of the Securities maintained pursuant to Section 6
hereof, or, in the case of payments of principal, to such other address as the
registered owner shall provide in writing at the time of such surrender;
provided, however, that such payments may be made, in the case of a registered
owner of greater than $1,000,000 aggregate principal amount of Securities, by
transfer to an account maintained by the payee with a bank if such registered
owner so elects by giving notice to the Fiscal Agent, not less than 15 days (or
such fewer days as the Fiscal Agent may accept at its discretion) prior to the
date of the payments to be obtained, of such election and of the account to
which payment is to be made.

                  (b)   Cancellation. All Securities delivered to the Fiscal
Agent (or any other Agent appointed pursuant to Section 2 hereof) for payment,
redemption, registration of transfer or exchange as herein or in the Securities
provided shall be forwarded to the Fiscal Agent by the Agent to which they are
delivered. All such Securities shall be canceled and destroyed by the Fiscal
Agent or such other person as may be jointly designated by the Issuer and the
Fiscal Agent which shall thereupon furnish certificates of such destruction to
the Issuer upon the Issuer's request.

5.      Exchange of Securities.

         The Fiscal Agent, or its agent duly authorized by the Fiscal Agent, is
hereby authorized from time to time in accordance with the provisions of the
Securities, Section 1(e) and of this Section to authenticate and deliver:

           (i)    Securities in exchange for or in lieu of Securities of like
                  tenor and of like form which become mutilated, destroyed,
                  stolen or lost; and

           (ii)   registered Securities of authorized denominations in exchange
                  for a like aggregate principal amount of Securities of like
                  tenor and of like form.

         The Securities shall be dated the date of their authentication by the
Fiscal Agent. Each Security authenticated and delivered upon any transfer or
exchange for or in lieu of the whole or any part of any Security shall carry all
the rights if any, to interest accrued and unpaid and to accrue which were
carried by the whole or such part of such Security. Notwithstanding anything to
the contrary herein contained, such new Security shall be so dated that neither
gain nor loss in interest shall result from such transfer or exchange.

6.      Register: Record Date for Certain Actions.

                                      -4-

<PAGE>

         The Fiscal Agent, as agent of the Issuer, shall maintain at its
corporate trust office in Houston, Texas and at its agent's office in the
Borough of Manhattan, The City of New York, a register for the Securities for
the registration and registration of transfers of the Securities. Upon
presentation for the purpose at the said office of the Fiscal Agent or its agent
of any Security, accompanied by a written instrument of transfer in the form
approved by the Issuer and the Fiscal Agent (it being understood that, until
notice to the contrary is given to holders of Securities, the Issuer and the
Fiscal Agent shall each be deemed to have approved the form of instrument of
transfer, if any, printed on any definitive Security), executed by the
registered holder, in person or by such holder's attorney thereunto duly
authorized in writing, such Security shall be transferred upon the register for
the Securities, and a new Security of like tenor shall be authenticated and
issued in the name of the transferee. Transfers and exchanges of Securities
shall be subject to Section 1(e), to such restrictions as shall be set forth in
the text of the Securities and to such reasonable regulations as may be
prescribed by the Issuer and the Fiscal Agent. Successive registrations and
registrations of transfers as aforesaid may be made from time to time as desired
and each such registration shall be noted on the Security register. No service
charge shall be made for any registration, registration of transfer or exchange
of Securities, but, except as otherwise provided herein with respect to the
exchange of temporary Securities for definitive Securities, the Fiscal Agent
(and any Transfer Agent or authenticating agent appointed pursuant to Section 2
or 3 hereof, respectively) may require payment of a sum sufficient to cover any
stamp or other tax or governmental charge in connection therewith and any other
amounts required to be paid by the provisions of the Securities.

         Any Transfer Agent appointed pursuant to Section 2 hereof shall provide
to the Fiscal Agent such information as the Fiscal Agent may reasonably require
in connection with the delivery by such Transfer Agent of Securities in exchange
for other Securities.

         Neither the Fiscal Agent nor any Transfer Agent shall be required to
make registrations of transfer or exchange of Securities during any periods set
forth in the text of the Securities.

         Upon receipt by the Fiscal Agent of any written demand, request or
notice with respect to any matter on which the holders of Securities are
entitled to act under this Agreement, a record date shall be established for
determining holders of Outstanding Securities entitled to join in such demand,
request or notice, which record date shall be at the close of business on the
day the Fiscal Agent receives such demand, request or notice. The holders on
such record date, or their duly designated proxies, and only such persons, shall
be entitled to join in such demand, request or notice, whether or not such
holders remain holders after such record date; provided, however, unless the
holders of the requisite principal amount of the Outstanding Securities shall
have joined in such demand, request or notice prior to the day which is the
ninetieth day after such record date, such demand, request or notice shall
automatically and without further action by any holder be cancelled and of no
further effect. Nothing in this paragraph shall prevent a holder or a proxy of a
holder, from giving, (i) after expiration of such 90-day period, a new demand,
request or notice identical to a demand, request or notice which has been
cancelled pursuant to the proviso in the preceding sentence or (ii) during any
such 90-day period, a new demand, request or notice contrary to or different
from such demand, request or notice, in either of which events a new record date
shall be established pursuant to the provisions of this paragraph.

         The Issuer may, but shall not be obligated to, fix a record date for
the purpose of determining the persons entitled to consent to or approve any
action or waive any term, provision or condition of any covenant of this
Agreement. If a record date is fixed, the holders on such record date, or their
duly designated proxies, and only such persons, shall be entitled to consent to
or approve any such action or waive any such term, provision, condition or
covenant, whether or not such holders remain holders after such record date;
provided, however, that unless such consent, waiver or approval is obtained from
the requisite principal amount of holders of Outstanding Securities, or their
duly designated proxies, prior to the date which is the ninetieth day after such
record date, any such consent, waiver or approval previously given shall
automatically and without further action by any holder be cancelled and of no
further effect.

7.      Delivery of Certain Information.

                                      -5-

<PAGE>

                  (a)   Non-Reporting Issuer. Subject to Section 7(b), as
long as the Issuer is not subject to Section 13 or 15(d) of the Securities
Exchange Act of 1934, as amended ("Exchange Act"), at any time upon the request
of a registered holder of a Security, the Issuer, or the Fiscal Agent upon
request by and at the expense of the Issuer, will promptly furnish or cause to
be furnished "Rule 144A Information" (as defined below) with respect to the
Issuer to such holder or to a prospective purchaser of such Security designated
by such holder in order to permit compliance by such holder with Rule 144A under
the Act in connection with the resale of such Security by such holder. "Rule
144A Information" with respect to the Issuer shall be such information with
respect to it as is specified pursuant to Rule 144A(d)(4)(i) under the Act (or
any successor provision thereto) which, at the date of this Agreement, consists
of (x) a very brief statement of the nature of the business, products and
services of the Issuer, as the case may be, (which statement shall be as of a
date within 12 months prior to the date of the intended resale) and (y) the most
recent financial statements of the Issuer and its financial statements for the
two fiscal years preceding the period covered in the most recent financial
statements. Such financial statements of the Issuer shall include its balance
sheet (as of a date less than 16 months before the date of the intended resale)
and its profit and loss and retained earnings statements (for the twelve month
period preceding the date of such balance sheet and, if the balance sheet is not
as of a date less than six months before the date of the intended resale, the
most recent profit and loss and retained earnings statements shall be for the
period from the date of such balance sheet to a date less than six months before
the date of the intended resale) and shall be audited to the extent reasonably
available.

                  (b)   Information After Three Years. Neither the Issuer,
nor the Fiscal Agent shall be required to furnish Rule 144A Information with
respect to the Issuer as contemplated by Sections 7(a) and 7(b), (x) to the
holder or a prospective purchaser of a Security in connection with any request
made on or after the date which is three years from the later of (i) the date
such Security (or any predecessor Security) was acquired from the Issuer or (ii)
the date such Security (or any predecessor Security) was last acquired from an
"affiliate" of the Issuer within the meaning of Rule 144 under the Act or (y) at
any time to a prospective purchaser located outside the United States who is not
a "U.S. person" within the meaning of Regulation S under the Act.

                  (c)   Periodic Reports. So long as any Securities are
Outstanding (as defined in Section 11(c) hereof), the Issuer, or the Fiscal
Agent upon request by and at the expense of the Issuer, will furnish or cause to
be furnished to holders of Securities and to the Fiscal Agent, (i) at any time
when the Issuer is subject to Section 13 or 15(d) of the Exchange Act, copies of
its annual and quarterly reports to stockholders and of each report or
definitive proxy statement filed with the Securities and Exchange Commission
(the "Commission") under the Exchange Act, such reports or statements to be so
furnished within 15 days after the due date for filing with the Commission, and
(ii) at any time when the Issuer is not subject to Section 13 or 15(d) of the
Exchange Act, (A) its annual financial statements prepared in accordance with
generally accepted accounting principles applied consistently (except as
otherwise noted therein) with those of the prior years (together with notes
thereto and a report thereon by an independent accounting firm of established
national reputation), such report to be so furnished as soon as reasonably
available and in any event within 120 days after the end of the fiscal year
covered thereby, (B) its unaudited comparative financial statements for each of
the first three fiscal quarters and the corresponding quarter of the prior year
prepared in accordance with generally accepted accounting principles applied
consistently (except as otherwise noted therein) with those of the most recent
annual financial statements (which unaudited statements and related notes may be
condensed to the extent permitted by Form 10-Q under the Exchange Act or any
successor form), such statements to be so furnished as soon as reasonably
available and in any event within 60 days after the end of the fiscal quarter
covered thereby, (C) any other interim reports or financial statements prepared
generally for its nonaffiliated investors or lenders, such reports or statements
to be so furnished concurrently with their distribution to such investors or
lenders, and (D) at each time of delivery of the financial statements in (A), a
certificate ("Officers' Certificate") signed by its Chairman of the Board, Vice
Chairman of the Board, President or a Vice President and by its Treasurer,
Assistant Treasurer, Secretary or an Assistant Secretary, and stating whether or
not to the best knowledge of the signers thereof the Issuer is in default in the
performance and observance of any of the terms, provisions and conditions of the
Securities or this Agreement and, if the Issuer shall be in default, specifying
all such defaults and the nature and status thereof of which they may have
knowledge.

                                      -6-
<PAGE>

8.      Conditions of Fiscal Agent's Obligations.

        The Fiscal Agent accepts its obligation herein set forth upon the terms
and conditions hereof, including the following, to all of which the Issuer
agrees and to all of which the rights of holders from time to time of Securities
are subject:

                  (a)   Compensation and Indemnity. The Fiscal Agent shall be
entitled to reasonable compensation as agreed with the Issuer for all services
rendered by it, and the Issuer agrees promptly to pay such compensation and to
reimburse the Fiscal Agent for the reasonable out-of-pocket expenses (including
reasonable counsel fees) incurred by it in connection with its services
hereunder. The Issuer also agrees to indemnify the Fiscal Agent for, and to hold
it harmless against, any loss, liability or expense, incurred without negligence
or bad faith, arising out of or in connection with its acting as Fiscal Agent or
in any other capacity hereunder, as well as the reasonable costs and expenses of
defending against any claim of liability in the premises. The obligations of the
Issuer under this Section 8(a) shall survive payment of all the Securities or
the resignation or removal of the Fiscal Agent.

                  (b)   Agency. In acting under this Agreement and in
connection with the Securities, the Fiscal Agent is acting solely as agent of
the Issuer and does not assume any responsibility for the correctness of the
recitals in the Securities (except for the correctness of the statement in its
certificate of authentication on the Securities) or any obligation or
relationship of agency or trust, for or with any of the owners or holders of the
Securities, except that all funds held by the Fiscal Agent for the payment of
principal of and any interest on the Securities shall be held in trust for such
owners or holders, as the case may be, as set forth herein and in the
Securities; provided, however, that monies held in respect of the Securities
remaining unclaimed at the end of two years after the principal of all of the
Securities shall have become due and payable (whether at maturity or otherwise)
and monies sufficient therefor shall have been duly made available for payment
shall, together with any interest made available for payment thereon, be repaid
to the Issuer as provided and in the manner set forth in the Securities. Upon
such repayment, the aforesaid trust with respect to the Securities shall
terminate and all liability of the Fiscal Agent and Paying Agents with respect
to such funds shall thereupon cease.

                  (c)   Advice of Counsel. The Fiscal Agent and any Paying
Agent or Transfer Agent appointed by the Issuer pursuant to Section 2 hereof may
consult with their respective counsel or other counsel satisfactory to them, and
the opinion of such counsel shall be full and complete authorization and
protection in respect of any action taken or suffered by them hereunder in good
faith and without negligence and in accordance with such opinion.

                  (d)   Reliance. The Fiscal Agent and any Paying Agent or
Transfer Agent appointed by the Issuer pursuant to Section 2 hereof each shall
be protected and shall incur no liability for or in respect of any action taken
or thing suffered by it in reliance upon any Security, notice, direction,
consent, certificate, affidavit, statement, or other paper or document believed
by it, in good faith and without negligence, to be genuine and to have been
passed or signed by the proper party or parties.

                  (e)   Interest in Securities, etc. The Fiscal Agent, any
authenticating agent, and any Paying Agent or Transfer Agent appointed by the
Issuer pursuant to Section 2 hereof and their respective officers, directors and
employees may become the owners of, or acquire any interest in, any Securities,
with the same rights that they would have if they were not the Fiscal Agent,
such authenticating agent, such other Paying Agent or Transfer Agent or such
person, and may engage or be interested in any financial or other transaction
with the Issuer, and may act on, or as depository, trustee or agent for, any
committee or body of holders of Securities or other obligations of the Issuer,
as freely as if they were not the Fiscal Agent, such authenticating agent, such
other Paying Agent or Transfer Agent or such person. The provisions of this
Section 8(e) shall extend to affiliates of the Fiscal Agent, such authenticating
agent, any Paying Agent or any Transfer Agent.

                  (f)   Certifications. Whenever in the administration of
this Agreement the Fiscal Agent shall deem it desirable that a matter be proved
or established prior to taking, suffering or omitting any action hereunder, the
Fiscal Agent (unless other evidence be herein specifically prescribed) may, in
the absence of bad faith or negligence on its part, rely upon a certificate
signed by any Authorized Officer of the Issuer and delivered to the Fiscal
Agent.

                                      -7-
<PAGE>

                  (g)   No Implied Obligations. The duties and obligations of
the Fiscal Agent shall be determined solely by the express provisions of this
Agreement, and the Fiscal Agent shall not be liable except for the performance
of such duties and obligations as are specifically set forth in this Agreement,
and no implied covenants or obligations shall be read into this Agreement
against the Fiscal Agent. In no event shall the Fiscal Agent be liable for any
lost profits, lost savings or other special, exemplary, consequential or
incidental damages.

                  (h)   No Liability. The Fiscal Agent shall not be liable
for any interest on any funds held by the Fiscal Agent and shall never be
required to use, advance or risk its own funds or otherwise incur financial
liability in the performance of its duties hereunder.

                  (i)   No Inquiry. The Fiscal Agent shall not be bound to
ascertain or inquire as to the performance or observance of any of the terms,
conditions, covenants or agreements of the Securities or other documents on the
part of the Issuer or as to the existence of any event of default thereunder.

                  (j)   Agents. The Fiscal Agent may execute any of its
trusts or powers or perform any duties under this Agreement either directly or
by or through agents or attorneys, may in all cases pay such reasonable
compensation as it deems proper to all such agents and attorneys reasonably
employed or retained by it, and shall not be responsible for any misconduct or
negligence of any agent or attorney appointed with due care by it.

9.      Resignation and Appointment of Successor.

                   (a)  Fiscal Agent and Paying Agent. The Issuer agrees, for
the benefit of the holders from time to time of the Securities, that there shall
at all times be a Fiscal Agent hereunder which shall be a bank or trust company
organized and doing business under the laws of the United States of America, any
state thereof or the District of Columbia, in good standing and having an
established place of business or agency in the Borough of Manhattan, The City of
New York, and authorized under such laws to exercise corporate trust powers
until all the Securities authenticated and delivered hereunder (i) shall have
been delivered to the Fiscal Agent for cancellation or (ii) become due and
payable and monies sufficient to pay the principal of and any interest on the
Securities shall have been made available for payment and either paid or
returned to the Issuer as provided herein and in such Securities.

                  (b)   Resignation. The Fiscal Agent may at any time resign
by giving written notice to the Issuer of such intention on its part, specifying
the date on which its desired resignation shall become effective, provided that
such date shall not be less than three (3) months from the date on which such
notice is given, unless the Issuer agrees to accept shorter notice. The Fiscal
Agent hereunder may be removed at any time by the filing with it of an
instrument in writing signed on behalf of the Issuer and specifying such removal
and the date when it shall become effective. Notwithstanding the dates of
effectiveness of resignation or removal, as the case may be, to be specified in
accordance with the preceding sentences, such resignation or removal shall take
effect only upon the appointment by the Issuer of a successor Fiscal Agent
(which, to qualify as such, shall be a bank or trust company organized and doing
business under the laws of the United States of America, any state thereof or
the District of Columbia, in good standing and having and acting through an
established place of business or agency in the Borough of Manhattan, The City of
New York, authorized under such laws to exercise corporate trust powers and
having a combined capital and surplus in excess of U.S. $20,000,000) and the
acceptance of such appointment by such successor Fiscal Agent. Upon its
resignation or removal, the Fiscal Agent shall be entitled to payment by the
Issuer pursuant to Section 8 hereof of compensation for services rendered and to
reimbursement of reasonable out-of-pocket expenses incurred hereunder.

                                      -8-

<PAGE>

                  (c)   Successors. In case at any time the Fiscal Agent or
any Paying Agent in respect of the Securities (if such Paying Agent is the only
Paying Agent located in a place where, by the terms of the Securities or this
Agreement, the Issuer is required to maintain a Paying Agent) shall resign, or
shall be removed, or shall become incapable of acting, or shall be adjudged
bankrupt or insolvent, or shall file a voluntary petition in bankruptcy or make
an assignment for the benefit of its creditors or consent to the appointment of
a receiver of all or any substantial part of its property, or shall admit in
writing its inability to pay or meet its debts as they severally mature, or if a
receiver of it or of all or any substantial part of its property shall be
appointed, or if an order of any court shall be entered approving any petition
filed by or against it under the provisions of the Federal Bankruptcy Act or
under the provisions of any similar legislation, or if a receiver of it or its
property shall be appointed, or if any public officer shall take charge or
control of it or of its property or affairs, for the purpose or rehabilitation,
conservation or liquidation, a successor Fiscal Agent or Paying Agent, as the
case may be, qualified as aforesaid, shall be appointed by the Issuer by an
instrument in writing, filed with the successor Fiscal Agent or Paying Agent, as
the case may be, and the predecessor Fiscal Agent or Paying Agent, as the case
may be. Upon the appointment as aforesaid of a successor Fiscal Agent or Paying
Agent, as the case may be, and acceptance by such successor of such appointment,
the Fiscal Agent or Paying Agent, as the case may be, so succeeded shall cease
to be Fiscal Agent or Paying Agent, as the case may be, hereunder. If no
successor Fiscal Agent or other Paying Agent, as the case may be, shall have
been so appointed by the Issuer and shall have accepted appointment as
hereinafter provided, and, in the case of such other Paying Agent, if such other
Paying Agent is the only Paying Agent located in a place where, by the terms of
the Securities of this Agreement, the Issuer is required to maintain a Paying
Agent, then any holder of a Security who has been a bona fide holder of a
Security for at least six months, on behalf of such holder and all others
similarly situated, or the Fiscal Agent may petition any court of competent
jurisdiction for the appointment of a successor agent. The Issuer shall give
prompt written notice to each other Paying Agent of the appointment of a
successor Fiscal Agent.

                  (d)   Acknowledgment. Any successor Fiscal Agent appointed
hereunder shall execute, acknowledge and deliver to its predecessor and to the
Issuer an instrument accepting such appointment hereunder, and thereupon such
successor Fiscal Agent, without any further act, deed or conveyance, shall
become vested with all the authority, rights, powers, trusts, immunities, duties
and obligations of such predecessor with like effect as if originally named as
Fiscal Agent hereunder, and such predecessor, upon payment of its compensation,
and reimbursement of its disbursements then unpaid, shall thereupon become
obligated to transfer, delivery and pay over, and such successor Fiscal Agent
shall be entitled to receive, all monies, securities, books, records or other
property on deposit with or held by such predecessor as Fiscal Agent hereunder.

                  (e)   Merger, Consolidation, etc. Any corporation into
which the Fiscal Agent hereunder may be merged, or any corporation resulting
from any merger or consolidation to which the Fiscal Agent shall be a party, or
any corporation to which the Fiscal Agent shall sell or otherwise transfer all
or substantially all of the corporate trust business of the Fiscal Agent,
provided that it shall be qualified as aforesaid, shall be the successor Fiscal
Agent under this Agreement without the execution or filing of any paper or any
further act on the part of any of the parties hereto.

10.      Payment of Taxes.

         The Issuer will pay all stamp and other duties, if any, which may be
imposed by the United States of America or any political subdivision thereof or
taxing authority of or in the foregoing with respect to this Agreement or the
issuance of the Securities.

11.      Amendments.

                                      -9-

<PAGE>

                  (a)   Approval. With the written consent of the registered
owners of not less than a majority in aggregate principal amount of the
Securities then Outstanding (or of such other percentage as may be set forth in
the text of the Securities with respect to the action being taken), the Issuer
and the Fiscal Agent may modify, amend or supplement the terms of the Securities
and this Agreement in any way, and the holders of Securities may make, take or
give any request, demand, authorization, direction, notice, consent, waiver or
other action provided by this Agreement or the Securities to be made, given or
taken by holders of Securities; provided, however, that no such action may,
without the consent of the holder of each Security affected thereby, (A) change
the due date for the payment of the principal of or any installment of interest
on any Security, (B) reduce the principal amount of any Security or the interest
rate thereon or any premium payable upon the redemption thereof, (C) change the
coin or currency in which or the place at which payment with respect to interest
or principal in respect of Securities are payable as required by the proviso of
the first sentence of the second paragraph of Section 2 hereof, or (D) reduce
the proportion of the principal amount of Securities, the consent of the holders
of which is necessary to modify, amend or supplement this Agreement or the terms
and conditions of the Securities or to make, take or give any request, demand,
authorization, direction, notice, consent, waiver or other action provided
hereby or thereby to be made, taken or given. The Issuer and the Fiscal Agent
may, without the consent of any holder of Securities, amend this Agreement or
the Securities for the purpose of curing any ambiguity, or of curing, correcting
or supplementing any defective provision thereof, hereof, or in any manner which
the Issuer and the Fiscal Agent may determine that shall not be inconsistent
with the Securities and shall not adversely affect the interest of any holder of
Securities.

                  It shall not be necessary for the consent of the holders of
Securities to approve the particular form of any proposed modification,
amendment, supplement, request, demand, authorization, direction, notice,
consent, waiver or other action, but it shall be sufficient if such consent
shall approve the substance thereof.

                  (b)   Binding Nature of Amendments, Notice, Notations, etc.
Any instrument given by or on behalf of any holder of a Security in connection
with any consent to any such modification, amendment, supplement, request,
demand, authorization, direction, notice, consent, waiver or other action will
be irrevocable once given and will be conclusive and binding on all subsequent
holders of such Security or any Security issued directly or indirectly in
exchange or substitution therefore or in lieu thereof. Any such modification,
amendment, supplement, request, demand, authorization, direction, notice,
consent, waiver or other action will be conclusive and binding on all holders of
Securities, whether or not they have given such consent, and whether or not
notation of such modification, amendment, supplement, request, demand,
authorization, direction, notice, consent, waiver or other action is made upon
the Securities. Notice of any modification or amendment of, supplement to, or
request, demand, authorization, direction, notice, consent, waiver or other
action with respect to the Securities or this Agreement (other than for purposes
of curing any ambiguity or of curing, correcting or supplementing any defective
provision hereof or thereof) shall be given to each holder of Securities
affected thereby, in all cases as provided in the Securities.

                  Securities authenticated and delivered after the effectiveness
of any such modification, amendment, supplement, request, demand, authorization,
direction, notice, consent, waiver or other action may bear a notation in the
form approved by the Fiscal Agent and the Issuer as to any matter provided for
in such modification, amendment, supplement, request, demand, authorization,
direction, notice, consent, waiver or other action. New Securities modified to
conform, in the opinion of the Fiscal Agent and the Issuer, to any such
modification, amendment, supplement, request, demand, authorization, direction,
notice, consent, waiver or other action may be prepared by the Issuer,
authenticated by the Fiscal Agent (or any authenticating agent appointed
pursuant to Section 3 hereof) and delivered in exchange for Outstanding
Securities.

                  (c)   "Outstanding" Defined. For purposes of the provisions
of this Agreement and the Securities, any Security authenticated and delivered
pursuant to this Agreement shall, as of any date of determination, be deemed to
be "Outstanding", except:

         (i)      Securities theretofore canceled by the Fiscal Agent or
                  delivered to the Fiscal Agent for cancellation or held by the
                  Fiscal Agent for reissuance but not reissued by the Fiscal
                  Agent;

                                      -10-
<PAGE>

         (ii)     Securities which have become due and payable at maturity or
                  otherwise and with respect to which monies sufficient to pay
                  the principal thereof and any interest thereon shall have been
                  made available to the Fiscal Agent; or

         (iii)    Securities which have been defeased pursuant to Section 14(b)
                  hereof; or

         (iv)     Securities in lieu of or in substitution for which other
                  Securities shall have been authenticated and delivered
                  pursuant to this Agreement

provided, however, that in determining whether the holders of the requisite
principal amount of Outstanding Securities have consented to any request,
demand, authorization, direction, notice, consent, waiver, amendment,
modification or supplement hereunder, Securities owned directly or indirectly by
the Issuer or any affiliate of the Issuer shall be disregarded and deemed not to
be Outstanding.

12.      GOVERNING LAW.

         THIS AGREEMENT SHALL BE GOVERNED BY, AND INTERPRETED IN ACCORDANCE
WITH, THE LAWS OF THE STATE OF NEW YORK, UNITED STATES OF AMERICA.

13.      Notices.

         All notices or communications hereunder, except as herein otherwise
specifically provided, shall be in writing and if sent to the Fiscal Agent shall
be delivered, transmitted by facsimile, telexed or telegraphed to it at 600
Travis Street, Suite 1150, Houston, Texas 77002, Attention: Global Trust
Services, facsimile no. (713) 216-5476 or if sent to the Issuer shall be
delivered, transmitted by facsimile, telexed or telegraphed to it at 1400 Smith
Street, Houston, Texas 77002 Attention: Vice President Finance and Accounting,
facsimile no. (713) 646-4761. The foregoing addresses for notices or
communications may be changed by written notice given by the addressee to each
party hereto, and the addressee's address shall be deemed changed for all
purposes from and after the giving of such notice.

         If the Fiscal Agent shall receive any notice or demand addressed to the
Issuer by the holder of a Security, the Fiscal Agent shall promptly forward such
notice or demand to the Issuer.

14.      Defeasance (Legal and Covenant).

                  (a)   Issuer's Option to Effect Defeasance or Covenant
Defeasance. The Issuer may at its option, by Order of the Issuer delivered to
the Fiscal Agent, elect to have either Section 14(b) or Section 14(c) applied to
the Outstanding Securities upon compliance with the conditions set forth below
in this Section 14.

                  (b)   Defeasance and Discharge. Upon exercise by the Issuer
of the option provided in Section 14(a) applicable to this Section 14(b), the
Issuer shall be deemed to have been discharged from its obligations with respect
to the Outstanding Securities on the date the conditions set forth below are
satisfied (hereinafter, "Defeasance"). For this purpose, such Defeasance means
that the Issuer shall be deemed to have paid and discharged the entire
Indebtedness represented by the Outstanding Securities and to have satisfied all
its other obligations under such Securities and this Agreement insofar as the
Securities are concerned (and the Issuer and the Fiscal Agent shall execute
proper instruments acknowledging the same), except for the following, which
shall survive until otherwise terminated or discharged hereunder: (i) the rights
of holders of the Securities to receive, solely from the trust fund described in
Section 14(d) and as more fully set forth in such Section, payments in respect
of the principal of and any interest on the Securities when such payments are
due, (ii) the Issuer's obligations with respect to the Securities under Sections
1(d), 2, 4(a), 5, 6, 7(a), 7(b) and 9 of this Agreement and paragraphs 3, 4(a),
9 (insofar as it relates to Sections 7(a) and 7(b) of this Agreement), 10 and 11
of the Securities and (iii) this Section 14. Subject to compliance with this
Section 14, the Issuer may exercise its option under this Section 14(b)
notwithstanding the prior exercise of its option under Section 14(c).

                                      -11-
<PAGE>

                  (c)   Covenant Defeasance. Upon the Issuer's exercise of
the option provided in Section 14(a) applicable to this Section 14(c), the
Issuer shall be released from its obligations under paragraphs 6(c), 7, and
8(a)(iii) of the Securities on and after the date the conditions set forth below
are satisfied (hereinafter, "Covenant Defeasance"). For this purpose, such
Covenant Defeasance means that the Issuer may omit to comply with and shall have
no liability in respect of any term, condition or limitation set forth in any
such Section, whether directly or indirectly by reason of any reference
elsewhere herein to any such Section or by reason of any reference in any such
Section to any other provision herein or in any other document, but the
remainder of the Issuer's obligations shall be unaffected thereby.

                  (d)   Conditions to Defeasance and Covenant Defeasance. The
following shall be the conditions to application of either Section 14(b) or
Section 14(c) to the then Outstanding Securities:

         (i)      The Issuer shall  irrevocably  have deposited or caused to be
                  deposited  with a trustee, who may be the Fiscal Agent and who
                  shall agree to comply with the provisions of this Section 14
                  applicable to it (the "Defeasance Trustee"), as trust funds in
                  trust for the purpose of making the  following  payments,
                  specifically pledged as security for, and dedicated solely to,
                  the benefit of the holders of the Securities,  (A) money in an
                  amount,  or (B) U.S.  Government Obligations  and/or  Eligible
                  Obligations  which through the scheduled  payment of principal
                  and interest in respect thereof in  accordance  with their
                  terms will provide, not later than one day before the due date
                  of any  payment, money in an amount,  or (C) a combination
                  thereof, sufficient, in the opinion of a nationally recognized
                  firm of independent public accountants  expressed in a written
                  certification thereof delivered to the Defeasance Trustee, to
                  pay and discharge, and which shall be applied by the
                  Defeasance Trustee to pay and discharge,  the principal of and
                  each installment of interest on the  Securities not later than
                  one day before the stated  maturity of such principal or
                  installment of interest in accordance  with the terms of this
                  Agreement and of the  Securities.  For this purpose: "U.S.
                  Government  Obligations"  means securities that are (x) direct
                  obligations of the United States of America for the payment of
                  which its full faith and credit are pledged or (y) obligations
                  of a person  controlled or supervised by and  acting  as an
                  agency or instrumentality of the United States of America  the
                  payment  of  which  is unconditionally  guaranteed as a full
                  faith and credit  obligation by the United States of America,
                  which, in either case,  are not callable or redeemable  at the
                  option of the issuer  thereof,  and shall also  include a
                  depository receipt  issued by a bank (as  defined in  Section
                  3(a)(2) of the Act) as custodian with respect to any such U.S.
                  Government Obligation or a specific payment of principal of or
                  interest on any such U.S. Government  Obligation held by such
                  custodian  for the account of the holder of such  depository
                  receipt,  provided that (except as required by law) such
                  custodian is not authorized to make any deduction from the
                  amount payable to the holder of such  depository receipt  from
                  any amount  received by the  custodian  in respect of the U.S.
                  Government Obligation  or the specific payment of principal of
                  or interest on the U.S.  Government  Obligation  evidenced by
                  such  depository  receipt;  and "Eligible  Obligations"  means
                  interest  bearing  obligations as a result of the deposit of
                  which the Securities are rated in the  highest  generic  long-
                  term debt rating category assigned to legally defeased debt by
                  one or more nationally recognized rating agencies.

         (ii)     In the case of an election under Section 14(b), the Issuer
                  shall have delivered to the Defeasance Trustee an opinion of
                  counsel stating that (x) the Issuer has received from, or
                  there has been published by, the U.S. Internal Revenue Service
                  a ruling, or (y) since the date of this Agreement there has
                  been a change in the applicable U.S. Federal income tax law,
                  in either case to the effect that, and based thereon such
                  opinion shall confirm that, the holders of the Outstanding
                  Securities will not recognize gain or loss for U.S. Federal
                  income tax purposes as a result of such deposit, defeasance
                  and discharge and will be subject to U.S. Federal income tax
                  on the same amount, in the same manner and at the same times
                  as would have been the case if such deposit, defeasance and
                  discharge had not occurred.

                                      -12-
<PAGE>

         (iii)    In the case of an election under Section 14(c), the Issuer
                  shall have delivered to the Defeasance Trustee an opinion of
                  counsel to the effect that the holders of the Outstanding
                  Securities will not recognize gain or loss for Federal income
                  tax purposes as a result of such deposit and covenant
                  defeasance and will be subject to Federal income tax on the
                  same amount, in the same manner and at the same times as would
                  have been the case if such deposit and covenant defeasance had
                  not occurred.

         (iv)     No event of default under paragraph 6 of the Securities or
                  event which with notice or lapse of time or both would become
                  such an event of default shall have occurred and be continuing
                  on the date of such deposit or, insofar as paragraphs 6(d) and
                  (e) of the Securities are concerned, at any time during the
                  period ending on the 121st day after the date of such deposit
                  (it being understood that this condition shall not be deemed
                  satisfied until the expiration of such period).

         (v)      Such defeasance or covenant defeasance shall not result in a
                  breach or violation of, or constitute a default under, any
                  other agreement or instrument to which the Issuer is a party
                  or by which it is bound.

         (vi)     The Issuer shall have delivered to the Fiscal Agent and the
                  Defeasance Trustee an Officers' Certificate and an opinion of
                  counsel, each stating that all conditions precedent provided
                  for relating to either the defeasance under Section 14(b) or
                  the covenant defeasance under Section 14(c) (as the case may
                  be) have been complied with.

         (vii)    Such defeasance or covenant defeasance shall not result in the
                  trust arising from such deposit constituting an investment
                  company as defined in the Investment Company Act of 1940, as
                  amended, or such trust shall be qualified under such act or
                  exempt from regulation thereunder.

                  (e)   Deposit in Trust: Miscellaneous. All money, U.S.
Government Obligations and Eligible Obligations (including the proceeds thereof)
deposited with the Defeasance Trustee pursuant to Section 14(d) in respect of
the Securities shall be held in trust and applied by the Defeasance Trustee, in
accordance with the provisions of the Securities and this Agreement, to the
payment, either directly or through any Paying Agent as the Defeasance Trustee
may determine, to the holders of the Securities, of all sums due and to become
due thereon in respect of principal and any interest, but such money need not be
segregated from other funds except to the extent required by law. Any money
deposited with the Defeasance Trustee for the payment of the principal of or any
interest on any Security and remaining unclaimed for two years after such
principal or interest has become due and payable shall be paid to the Issuer
upon Order and the holder of such Security shall thereafter, as an unsecured
general creditor, look only to the Issuer for payment thereof, and all liability
of the Defeasance Trustee with respect to such trust money shall thereupon
cease.

                  The Issuer shall pay and indemnify the Defeasance Trustee
against any tax, fee or other charge imposed on or assessed against the U.S.
Government Obligations or Eligible Obligations deposited pursuant to Section
14(d) or the principal and interest received in respect thereof other than any
such tax, fee or other charge which by law is for the account of the holders of
the Outstanding Securities.

                  Anything in this Section 14 to the contrary notwithstanding,
the Defeasance Trustee shall deliver or pay to the Issuer from time to time upon
the request of the Issuer any money, U.S. Government Obligations or Eligible
Obligations held by it as provided in Section 14(d) which, in the opinion of a
nationally recognized firm of independent public accountants expressed in a
written certification thereof delivered to the Defeasance Trustee, are in excess
of the amount thereof which would then be required to be deposited to effect an
equivalent defeasance or covenant defeasance.

                                      -13-

<PAGE>

                  (f)   Reinstatement. If the Defeasance Trustee is unable to
apply any money in accordance with Section 14(b) or 14(c) by reason of any order
or judgment of any court or governmental authority enjoining, restraining or
otherwise prohibiting such application, then the Issuer's obligations under this
Agreement and the Securities shall be revived and reinstated as though no
deposit had occurred pursuant to this Section 14 until such time as the
Defeasance Trustee is permitted to apply all such money in accordance with
Section 14(b) or 14(c); provided, however, that if the Issuer makes any payment
of principal of or interest on any Security following the reinstatement of its
obligations, the Issuer shall be subrogated to the rights of the holders of such
Securities to receive such payment from the money held by the Defeasance
Trustee.

15.      Headings

         The section headings herein are for convenience only and shall not
affect the construction hereof.

16.      Counterparts

         This agreement may be executed in one or more counterparts, and by each
party separately on a separate counterpart, and each such counterpart when
executed and delivered shall be deemed to be an original. Such counterparts
shall together constitute one and the same instrument.

17.      Successors and Assigns.

         All covenants and agreements in this Agreement by the Issuer shall bind
its respective successors and assigns, whether so expressed or not.

18.      Separability Clause

         In case any provision in this Agreement or in the Securities shall be
invalid, illegal or unenforceable, the validity, legality and enforceability of
the remaining provisions shall not in any way be affected or impaired thereby.

         IN WITNESS WHEREOF, the parties hereto have executed this Agreement as
of the date first above written.

                                NORTHERN NATURAL GAS COMPANY

                                  By /s/ George P. Fastuca
                                    ----------------------
                                        Name: George P. Fastuca
                                        Title: V.P., Finance and Accounting

                                 CHASE BANK OF TEXAS, NATIONAL ASSOCIATION,
                                        As Fiscal Agent.

                                 By___________________________________
                                        Authorized Signatory

                                      -14-

<PAGE>

                                    EXHIBIT A
                                FORM OF SECURITY

                                                                  [Form of Face
                                                                   of Security]

         THIS SECURITY (OR ITS PREDECESSOR) WAS ORIGINALLY ISSUED IN A
TRANSACTION EXEMPT FROM REGISTRATION UNDER THE UNITED STATES SECURITIES ACT OF
1933, AS AMENDED (THE "ACT"), AND MAY NOT BE SOLD OR OTHERWISE TRANSFERRED IN
THE ABSENCE OF SUCH REGISTRATION OR AN APPLICABLE EXEMPTION THEREFROM AND IN ANY
EVENT MAY BE SOLD OR OTHERWISE TRANSFERRED ONLY IN ACCORDANCE WITH THE FISCAL
AGENCY AGREEMENT, COPIES OF WHICH ARE AVAILABLE FOR INSPECTION AT THE CORPORATE
TRUST OFFICE OF THE FISCAL AGENT. THE EXEMPTION PROVIDED BY RULE 144A UNDER THE
ACT MAY BE AVAILABLE TO PERMIT SALE OR TRANSFER OF THIS SECURITY TO QUALIFIED
INSTITUTIONAL BUYERS (WITHIN THE MEANING OF RULE 144A) WITHOUT REGISTRATION.

         EACH HOLDER OF THIS SECURITY REPRESENTS TO THE ISSUER THAT (A) SUCH
HOLDER WILL NOT SELL OR OTHERWISE TRANSFER THIS SECURITY (WITHOUT CONSENT OF THE
ISSUER) PRIOR TO TWO YEARS FROM THE LATER OF SEPTEMBER 4, 1998 OR THE DATE ON
WHICH THIS SECURITY WAS LAST HELD BY AN AFFILIATE OF THE ISSUER OTHER THAN (I)
TO A QUALIFIED INSTITUTIONAL BUYER IN A TRANSACTION COMPLYING WITH RULE 144A,
(II) TO A NON-U.S. PERSON IN A TRANSACTION COMPLYING WITH REGULATIONS UNDER THE
ACT, (III) FOLLOWING ONE YEAR FROM SUCH TIME, IN A TRANSACTION COMPLYING WITH
RULE 144 UNDER THE ACT, OR (IV) PURSUANT TO ANOTHER AVAILABLE EXEMPTION FROM
REGISTRATION UNDER THE ACT (IT BEING UNDERSTOOD THAT AS A CONDITION TO THE
REGISTRATION OF TRANSFER OF THIS SECURITY, THE ISSUER OR THE FISCAL AGENT MAY,
IN CIRCUMSTANCES THEY BELIEVE APPROPRIATE, REQUIRE EVIDENCE AS TO COMPLIANCE
WITH ANY SUCH EXEMPTION) AND THAT (B) THE HOLDER WILL, AND EACH SUBSEQUENT
HOLDER IS REQUIRED TO, NOTIFY ANY PURCHASER OF THIS SECURITY FROM IT OF THE
RESALE RESTRICTIONS REFERRED TO IN (A) ABOVE.

         THE FOREGOING LEGENDS MAY BE REMOVED FROM THE SECURITIES ON THE
CONDITIONS SPECIFIED IN THE FISCAL AGENCY AGREEMENT.

                                      A-1
<PAGE>

         No. R-                                                  [Denomination]

                          NORTHERN NATURAL GAS COMPANY

                    6.75% Senior notes due September 15, 2008

         NORTHERN NATURAL GAS COMPANY, a corporation duly organized under the
laws of the State of Delaware (herein called the "Issuer"), for value received,
hereby promises to pay to ________________ or registered assigns, the principal
sum of ___________________ on September 15, 2008 and to pay interest thereon
from September 4, 1998 or from the most recent Interest Payment Date to which
interest has been paid or duly provided for, semi-annually in arrears on March
15 and September 15 in each year, commencing March 15, 1999 (each an "Interest
Payment Date"), at the rate of 6.75% per annum, until the principal hereof is
paid or made available for payment and (to the extent that the payment of such
interest shall be legally enforceable) at the rate per annum equal to the above
rate plus 1% per annum on any overdue principal and any overdue installment of
interest. Interest on the Securities shall be computed on the basis of 360-day
year of twelve 30-day months. The interest so payable, and punctually paid or
duly provided for, on any Interest Payment Date will, as provided in the Fiscal
Agency Agreement hereinafter referred to, be paid to the person (the "registered
holder") in whose name this Security (or one or more predecessor Securities) is
registered at the close of business on March 1 or September 1 (whether or not a
business day), as the case may be (each a "Regular Record Date"), next preceding
such Interest Payment Date. Any such interest not so punctually paid or duly
provided for will forthwith cease to be payable to the registered holder on such
Regular Record Date and shall be paid to the person in whose name this Security
(or one or more predecessor Securities) is registered at the close of business
on a special record date for the payment of such interest to be fixed by the
Issuer, notice whereof shall be given to registered holders of Securities not
less than 10 days prior to such special record date.

         Principal of this Security shall be payable against surrender hereof at
the corporate trust office or office of an agent of the Fiscal Agent hereinafter
referred to or at such other offices or agencies as the Issuer may designate and
at the offices of such other Paying Agents as the Issuer shall have appointed
pursuant to the Fiscal Agency Agreement. Payments of principal shall be made
against surrender of this Security, and payments of interest on this Security
shall be made, in accordance with the foregoing and subject to applicable laws
and regulations, by check mailed on or before the due date for such payment to
the person entitled thereto at such person's address appearing on the
aforementioned register or, in the case of payments of principal to such other
address as the registered holder may specify upon such surrender; provided,
however, that any payments shall be made, in the case of a registered holder of
at least $1,000,000 aggregate principal amount of Securities, by transfer to an
account maintained by the payee with a bank if such registered holder so elects
by giving notice to the Fiscal Agent, not less than 15 days (or such fewer days
as the Fiscal Agent may accept at its discretion) prior to the date of the
payments to be obtained, of such election and of the account to which payments
are to be made. The Issuer covenants that until this Security has been delivered
to the Fiscal Agent for cancellation, or monies sufficient to pay the principal
of and interest on this Security have been made available for payment and either
paid or returned to the Issuer as provided herein, it will at all times maintain
an established place of business or agency in the Borough of Manhattan, The City
of New York for the payment of the principal of and interest on the Securities
as herein provided.

         Reference is hereby made to the further provisions of this Security set
forth on the following pages hereof, which further provisions shall for all
purposes have the same effect as if set forth at this place.

         Unless the certificate of authentication hereon has been executed by
the Fiscal Agent by manual signature, this Security shall not be valid or
obligatory for any purpose.

                                      A-2
<PAGE>

         IN WITNESS WHEREOF, the Issuer has caused this instrument to be duly
executed and its corporate seal to be affixed hereto.

         Date:                              NORTHERN NATURAL GAS COMPANY

                                            By__________________________________
                                                   George P. Fastuca
                                                   Vice President, Finance and
                                                   Accounting

[Corporate Seal]

Attest:

______________________________
Vice President and Secretary

                  This is one of the Securities referred to in the within-
mentioned Fiscal Agency Agreement.

                                            CHASE BANK OF TEXAS, NATIONAL
                                                ASSOCIATION,
                                                as Fiscal Agent.

                                            By_________________________________

Date of Authentication: ___________

                                      A-3
<PAGE>

                                                               [Form of reverse
                                                                   of Security]

l.      This Security is one of a duly authorized issue of securities of the
Issuer designated as its 6.75% Senior Notes due September 15, 2008 (herein
called the "Securities"), limited in aggregate principal amount to $150,000,000,
issued and to be issued in accordance with a Fiscal Agency Agreement, dated as
of September 4, 1998 (herein called the "Fiscal Agency Agreement"), between the
Issuer and Chase Bank of Texas, National Association, as Fiscal Agent (herein
called the "Fiscal Agent", which term includes any successor fiscal agent under
the Fiscal Agency Agreement), copies of which Fiscal Agency Agreement are on
file and available for inspection at the corporate trust office of the Fiscal
Agent which at the date hereof is at 600 Travis Street, Suite 1150, Houston,
Texas 77002.

         The Securities are unsecured direct, unconditional and general
obligations of the Issuer and will rank equally with all other unsecured and
unsubordinated indebtedness of the Issuer.

2.       The Securities are issuable only in fully registered form, without
coupons, in minimum denominations of U.S. $100,000 and integral multiples of
$1,000 above that amount.

3.       The Issuer shall maintain in the Borough of Manhattan, The City of
New York, an established place of business or agency where Securities may be
surrendered for registration of transfer or exchange. The Issuer has initially
appointed the Fiscal Agent acting through its corporate trust office in Houston,
Texas and as its agent's office in the Borough of Manhattan, The City Of New
York, as their agent for such purpose and the Issuer has agreed to cause to be
kept at such offices a register in which, subject to such reasonable regulations
as it may prescribe, the Issuer will provide for the registration of Securities
and of transfers of Securities. The Issuer reserves the right to vary or
terminate the appointment of the Fiscal Agent as security registrar or of any
Transfer Agent or to appoint additional or other registrars or Transfer Agents
or to approve any change in the office through which any security registrar or
any Transfer Agent acts, provided that there will at all times be a security
registrar or agent thereof in the Borough of Manhattan, The City of New York.
Registered holders of the Securities will receive notice of any such change.

         The transfer of a Security is registrable on the aforementioned
register upon surrender of such Security at the corporate trust office of the
Fiscal Agent or the office of the agent of the Fiscal Agent or any Transfer
Agent duly endorsed by, or accompanied by a written instrument of transfer in
form satisfactory to the Issuer and the Fiscal Agent duly executed by, the
registered holder thereof or such holder's attorney duly authorized in writing.
Upon such surrender of this Security for registration of transfer, the issuer
shall execute, and the Fiscal Agent shall authenticate and deliver, in the name
of the designated transferee or transferees, one or more new Securities, dated
the date of authentication thereof, of any authorized denominations and of a
like aggregate principal amount.

         At the option of the registered holder upon request confirmed in
writing, Securities may be exchanged for Securities of any authorized
denominations and of a like tenor, form and aggregate principal amount upon
surrender of the Securities to be exchanged at the office of any Transfer Agent
or at the corporate trust office of the Fiscal Agent or agent thereof. Whenever
any Securities are so surrendered for exchange, the Issuer shall execute, and
the Fiscal Agent shall authenticate and deliver, the Securities which the
registered holder making the exchange is entitled to receive. Any registration
of transfer or exchange will be effected upon the Transfer Agent or the Fiscal
Agent, as the case may be, being satisfied with the documents of title and
identity of the person making the request and subject to such reasonable
regulations as the Issuer may from time to time agree with the Transfer Agent
and the Fiscal Agent.

         All Securities issued upon any registration of transfer or exchange of
Securities shall be the valid obligations, of the Issuer evidencing the same
debt and entitled to the same benefits, as the Securities surrendered upon such
registration of transfer or exchange. No service charge shall be made for any
registration of transfer or exchange, but the Issuer may require payment of a
sum sufficient to cover any tax or other governmental charge payable in
connection therewith.

                                      A-4

<PAGE>

         Prior to due presentment of this Security for registration of transfer,
the Issuer, the Fiscal Agent and any agent of the Issuer or the Fiscal Agent may
treat the person in whose name this Security is registered as the owner hereof
for all purposes, whether or not this Security be overdue, and neither the
Issuer, the Fiscal Agent nor any such agent shall be affected by notice to the
contrary.

4.              (a)     The Issuer shall pay to the Fiscal Agent at its
principal office in Houston, Texas on or prior to each Interest Payment Date and
the maturity date of the Securities, in such amounts sufficient (with any
amounts then held by the Fiscal Agent and available for the purpose) to pay the
interest on and the principal of the Securities due and payable on such Interest
Payment Date or maturity date, as the case may be in funds available on such
date. The Fiscal Agent shall apply the amounts so paid to it to the payment of
such interest and principal in accordance with the terms of the Securities. Any
monies paid by the Issuer to the Fiscal Agent for the payment of the principal
of or interest on any Securities and remaining unclaimed at the end of two years
after such principal or interest shall have become due and payable (whether at
maturity or otherwise) shall then be repaid to the Issuer upon its written
request, and upon such repayment all liability of the Fiscal Agent with respect
thereto shall cease, without, however, limiting in any way any obligation the
Issuer may have to pay the principal of and interest on this Security as the
same shall become due.

                  (b)   In any case where the due date for the payment of the
principal of or interest on any Security shall be at any place of payment a day
on which banking institutions are authorized or obligated by law to close, then
payment of principal or interest need not be made on such date at such place but
may be made on the next succeeding day at such place which is not a day on which
banking institutions are authorized or obligated by law to close, with the same
force and effect as if made on the date for such payment, and no interest shall
accrue for the period after such date.

5.       The Issuer shall pay all stamp and other duties, if any, which may
be imposed by the United States or any political subdivision thereof or taxing
authority of or in the foregoing with respect to the Fiscal Agency Agreement or
the issuance of this Security. Except as otherwise provided in this Security,
the Issuer shall not be required to make any payment with respect to any tax,
assessment or other governmental charge imposed by any government or any
political subdivision or taxing authority thereof or therein.

6.       In the event of:

                  (i) default in the payment of any interest on any Security for
         a period of 30 days after the date when due; or

                  (ii) default in the payment of the principal of any Security
         when due (whether at maturity or otherwise); or

                  (iii) default in the performance or breach of any other
         covenant or agreement of the Issuer contained in the Securities or in
         the Fiscal Agency Agreement for a period of 60 days after the date on
         which written notice of such default requiring the Issuer to remedy the
         same and stating that such notice is a "Notice of Default" shall first
         have been given to the Issuer and the Fiscal Agent by the holders of at
         least 25% in principal amount of the Securities at the time Outstanding
         (as defined in the Fiscal Agency Agreement); or

                  (iv) the entry by a court having jurisdiction in the premises
         of (1) a decree or order for relief in respect of the Issuer in an
         involuntary case or proceeding under any applicable Federal or State
         bankruptcy, insolvency, reorganization or other similar law or (2) a
         decree or order adjudging the Issuer bankrupt or insolvent, or
         approving as properly filed a petition seeking reorganization,
         arrangement, adjustment or composition of or in respect of the Issuer
         under any applicable Federal or State law, or appointing a custodian,
         receiver, liquidator, assignee, trustee, sequestrator or other similar
         official of the Issuer or of any substantial part of the property of
         the Issuer, or ordering the winding up or liquidation of the affairs of
         the Issuer, and any such decree or order for relief or any such other
         decree or order shall continue unstayed and in effect for a period of
         60 consecutive days; or

                                      A-5

<PAGE>

                  (v) commencement by the Issuer of a voluntary case or
         proceeding under any applicable Federal or State bankruptcy,
         insolvency, reorganization or other similar law or of any other case or
         proceeding to be adjudicated a bankrupt or insolvent, or the consent by
         the Issuer to the entry of a decree or order for relief in respect of
         the Issuer in an involuntary case or proceeding under any applicable
         Federal or State bankruptcy, insolvency, reorganization or other
         similar law or to the commencement of any bankruptcy or insolvency case
         or proceeding against the Issuer, or the filing by the Issuer of a
         petition or answer or consent seeking reorganization or relief under
         any such applicable Federal or State law, or the consent by the Issuer
         to the filing of such petition or to the appointment of or the taking
         possession by a custodian, receiver, liquidator, assignee, trustee,
         sequestrator or other similar official of the Issuer or of any
         substantial part of its property, or the making by the Issuer of an
         assignment for the benefit of creditors, or the taking of action by the
         Issuer in furtherance of any such action;

the registered holder of this Security may, at such holder's option, declare the
principal of this Security and the interest accrued hereon to be due and payable
immediately by written notice to the Issuer and the Fiscal Agent at its
corporate trust office, and unless all such defaults shall have been cured by
the Issuer prior to receipt of such written notice, the principal of the
Security and the interest accrued thereon shall become and be immediately due
and payable. For purposes of the Securities, "Subsidiary" of the Issuer means a
corporation all of the outstanding voting stock of which is owned, directly or
indirectly, by the Issuer or by one or more other Subsidiaries. For the purposes
of this definition, "voting stock" means stock which ordinarily has voting power
for the election of directors, whether at all times or only so long as no senior
class of stock has such voting power by reason of any contingency.

7.      So long as any of the Securities are Outstanding, the Issuer will
not pledge, mortgage or hypothecate, or permit to exist, and will not cause,
suffer or permit any Subsidiary of it to pledge, mortgage or hypothecate, or
permit to exist, except in favor of the Issuer or any Subsidiary of it, any
mortgage pledge or other lien upon, any Principal Property (as hereinafter
defined) at any time owned by it, to secure any Indebtedness ( as hereinafter
defined) of it, without making effective provision whereby the Outstanding
Securities shall be equally and ratably secured with any and all such
indebtedness of it similarly entitled to be equally and ratably secured;
provided, however, that this restriction shall not apply to or prevent the
creation or existence of:

                  (i) undetermined or inchoate liens and charges incidental to
         construction, maintenance, development or operation;

                  (ii) any liens of taxes and assessments for the current year;

                  (iii) any liens of taxes and assessments not at the time
         delinquent;

                  (iv) any liens of specified taxes and assessments which are
         delinquent but the validity of which is being contested in good faith
         at the time by the Issuer or any Subsidiary of it;

                  (v) any liens reserved in leases for rent and for compliance
         with the terms of the lease in the case of leasehold estates;

                  (vi) any obligations or duties, affecting the property of the
         Issuer or any Subsidiary of it, to any municipality or public authority
         with respect to any franchise, grant, license, permit or similar
         arrangement;

                  (vii) the liens of any judgments or attachments in an
         aggregate amount not in excess of $10,000,000, or the lien of any
         judgment or attachment the execution or enforcement of which has been
         stayed or which has been appealed and secured, if necessary, by the
         filing of an appeal bond;

                                      A-6

<PAGE>

                  (viii) any mortgage, pledge, lien or encumbrance on any
         property held or used by the Issuer or any Subsidiary of it in
         connection with the exploration for, development of or production of
         oil, gas, natural gas (including liquified gas and storage gas), other
         hydrocarbons, helium, coal, metals, minerals, steam, timber, geothermal
         or other natural resources or synthetic fuels, such properties to
         include, but not be limited to, the interest of the Issuer or such
         Subsidiary in any mineral fee interests, oil, gas or other mineral
         leases, royalty, overriding royalty or net profits interests,
         production payments and other similar interests, wellhead production
         equipment, tanks, field gathering lines, leasehold or field separation
         and processing facilities, compression facilities and other similar
         personal property and fixtures;

                  (ix) any mortgage, pledge, lien or encumbrance on oil, gas,
         natural gas (including liquified gas and storage gas), and other
         hydrocarbons, helium, coal, metals, minerals, steam, timber, geothermal
         or other natural resources or synthetic fuels produced or recovered
         from any property, an interest in which is owned or leased by the
         issuer or any Subsidiary of it;

                  (x) mortgages, pledges, liens or encumbrances upon any
         property heretofore or hereafter acquired, created at the time of
         acquisition or within 365 days thereafter to secure all or a portion of
         the purchase price thereof, or existing thereon at the date of
         acquisition, whether or not assumed by the Issuer or any Subsidiary of
         it, provided that every such mortgage, pledge, lien or encumbrance
         shall apply only to the property so acquired and fixed improvements
         thereon;

                  (xi) any extension, renewal or refunding, in whole or in part,
         of any mortgage, pledge, lien or encumbrance permitted by Section (x)
         above, if limited to the same property or any portion thereof subject
         to, and securing not more than the amount secured by, the mortgage,
         pledge, lien or encumbrance extended, renewed or refunded;

                  (xii) mortgages, pledges, liens or encumbrances upon any
         property heretofore or hereafter acquired by any corporation that is or
         becomes such a Subsidiary of the Issuer after the date of the Fiscal
         Agency Agreement ("Acquired Entity"), provided that every such
         mortgage, pledge, lien or encumbrance (1) shall either (a) exist prior
         to the time the Acquired Entity becomes such a Subsidiary or (b) be
         created at the time the Acquired Entity becomes such a Subsidiary or
         within 365 days thereafter to secure all or a portion of the
         acquisition price thereof and (2) shall only apply to those properties
         owned by the Acquired Entity at the time it becomes such a Subsidiary
         or thereafter acquired by it from sources other than the Issuer or any
         other Subsidiary of it;

                  (xiii) the pledge of current assets, in the ordinary course of
         business, to secure current liabilities;

                  (xiv) mechanics' or materialmen's liens, any liens or charges
         arising by reason of pledges or deposits to secure payment of workmen's
         compensation or other insurance, good faith deposits in connection with
         tenders, leases of real estate, bids or contracts (other than contracts
         for the payment of money), deposits to secure duties or public or
         statutory obligations, deposits to secure, or in lieu, surety, stay or
         appeal bonds, and deposits as security for the payment of taxes or
         assessments or similar charges;

                  (xv) any lien arising by reason of deposits with, or the
         giving of any form of security to, any governmental agency or any body
         created or approved by law or governmental regulation for any purpose
         at any time in connection with the financing of the acquisition or
         construction of property to be used in the business of the Issuer or
         any Subsidiary of it or as required by law or governmental regulation
         as a condition to the transaction of any business or the exercise of
         any privilege or license, or to enable the Issuer or any such
         Subsidiary to maintain self-insurance or to participate in any funds
         established to cover any insurance risks or in connection with
         workmen's compensation, unemployment insurance, old age pensions or
         other social security, or to share in the privileges or benefits
         required for companies participating in such arrangements;

                  (xvi) any lien to secure Indebtedness of the Issuer other than
         Funded Debt (as hereinafter defined);

                                      A-7
<PAGE>

                  (xvii) any mortgage, pledge, lien or encumbrance of or upon
         any office equipment, data processing equipment (including, without
         limitation, computer and computer peripheral equipment), or
         transportation equipment (including with limitation, motor vehicles,
         tractors, trailers, marine vessels, barges, towboats, rolling stock and
         aircraft);

                  (xviii) any mortgage, pledge, lien or encumbrance created or
         assumed by the Issuer or any Subsidiary of it in connection with the
         issuance of debt securities the interest on which is excludable from
         gross income of the holder of such security pursuant to the Internal
         Revenue Code of 1986, as amended, for the purpose of financing, in
         whole or in part, the acquisition or construction of property to be
         used by the Issuer or any such Subsidiary; or

                  (xix) the pledge or assignment of accounts receivable, or the
         pledge or assignment of conditional sales contracts or chattel
         mortgages and evidences of indebtedness secured thereby, received in
         connection with the sale by the Issuer or any Subsidiary of it of goods
         or merchandise to customers of the Issuer or any Subsidiary.

         In case the Issuer or any Subsidiary of it shall propose to pledge,
mortgage or hypothecate any Principal Property at any time owned by it to secure
any of its Indebtedness, other than as permitted by subdivisions (i) to (xix),
inclusive, of this Paragraph 7, the Issuer will prior thereto give written
notice thereof to the Fiscal Agent, and the Issuer will, or will cause such
Subsidiary to, prior to or simultaneously with such pledge, mortgage or
hypothecation, effectively secure all the Securities equally and ratably with
such Indebtedness.

         Notwithstanding the foregoing provisions of this Paragraph 7, the
Issuer or any Subsidiary of it may issue, assume or guarantee Indebtedness
secured by a mortgage which would otherwise be subject to the foregoing
restrictions in an aggregate amount which, together with all other Indebtedness
of the Issuer or a Subsidiary of it secured by a mortgage which (if originally
issued, assumed or guaranteed at such time) would otherwise be subject to the
foregoing restrictions (not including Indebtedness permitted to be secured under
clauses (i) through (xix) above), does not at the time exceed 10% of the
Consolidated Net Tangible Assets of the Issuer as shown on its audited
consolidated financial statements as of the end of the fiscal year preceding the
date of determination.

         For purposes of the Securities,

         "Consolidated Net Tangible Assets" of any corporation means total
assets less (a) total current liabilities (excluding indebtedness due within 365
days) and (b) goodwill, patents and trademarks, all as reflected in such
corporation's audited consolidated balance sheet preceding the date of a
determination under the immediately preceding paragraph of this Paragraph 7.

         "Funded Debt" as applied to any corporation means all Indebtedness
incurred, created, assumed or guaranteed by such corporation, or upon which it
customarily pays interest charges, which matures, or is renewable by such
corporation to a date, more than one year after the date as of which Funded Debt
is being determined; provided, however, that the term "Funded Debt" shall not
include (i) Indebtedness incurred in the ordinary course of business
representing borrowings, regardless of when payable, of such corporation from
time to time against, but not in excess of the face amount of, its installment
accounts receivable for the sale of appliances and equipment sold in the regular
course of business or (ii) advances for construction and security deposits
received by such corporation in the ordinary course of business.

                                      A-8

<PAGE>

         "Indebtedness" as applied to any corporation, shall mean bonds,
debentures, notes and other instruments representing obligations created or
assumed by any such corporation for the repayment of money borrowed (other than
unamortized debt discount or premium). All Indebtedness secured by a lien upon
property owned by any corporation and upon which Indebtedness any such
corporation customarily pays interest, although any such corporation has not
assumed or become liable for the payment of such Indebtedness, shall for all
purposes of the Securities be deemed to be Indebtedness of any such corporation.
All Indebtedness for money borrowed incurred by other persons which is directly
guaranteed as to payment of principal by any corporation shall for all purposes
of the Securities be deemed to be Indebtedness of such corporation, but no other
contingent obligation of such corporation in respect of Indebtedness incurred by
other persons shall for any purpose be deemed Indebtedness of such corporation.
Indebtedness of any corporation shall not include: (i) amounts which are payable
only out of all or a portion of the oil, gas, natural gas, helium, coal, metals,
minerals, steam, timber, hydrocarbons, or geothermal or other natural resources
produced, derived, or extracted from properties owned or developed by such
corporation; (ii) any amount representing capitalized lease obligations; (iii)
any indebtedness incurred to finance oil, gas, natural gas, helium, coal, metal,
mineral, steam, timber, hydrocarbons, or geothermal or other natural resources
or synthetic fuel exploration or development, payable with respect to principal
and interest, solely out of the proceeds of oil, gas, natural gas, helium, coal,
metals, minerals, steam, timber, hydrocarbons, or geothermal or other natural
resources or synthetic fuel to be produced, sold, and/or delivered by any such
corporation; (iv) indirect guarantees or other contingent obligations in
connection with the Indebtedness of others, including agreements, contingent or
otherwise, with such other persons or with third persons with respect to, or to
permit or ensure the payment of, obligations of such other persons, including,
without limitation, agreements to purchase or repurchase obligations of such
other persons, agreements to advance or supply funds to or to invest in such
other persons, or agreements to pay for property, products, or services of such
other persons (whether or not conferred, delivered or rendered), and any demand
charge, throughput, take-or-pay, keep-well, make-whole, cash deficiency,
maintenance of working capital or earnings or similar agreements; and (v) any
guarantees with respect to lease or other similar periodic payments to be made
by other persons.

         "Principal Property" of the Issuer means any oil or gas pipeline, gas
processing plant or chemical plant located in the United States, except any such
pipeline, facility, station or plant that in the opinion of the Board of
Directors of the Issuer is not of material importance to the total business
conducted by the Issuer or its Subsidiaries. "Principal Property" shall not
include any oil or gas property, the production or any proceeds of production
from an oil or gas producing property or the production or any proceeds of
production of gas processing plants or oil or gas or petroleum products in any
pipeline. "Principal Property" shall also include any gas storage facility or
gas compressor station located in the United States, except any such facility or
station that in the opinion of the Board of Directors of the Issuer is not of
material importance to the total business conducted by the Issuer or its
Subsidiaries, and "Principal Property" shall not include any liquified natural
gas plants and related storage facilities or any natural gas liquids processing
plants.

8.       (a)    The Issuer shall not consolidate with or merge into any
other person or convey, transfer or lease its properties and assets
substantially as an entirety to any person, and the Issuer shall not permit any
person to consolidate with or merge into the Issuer or convey, transfer or lease
its properties and assets substantially as an entirety to the Issuer unless:

                           (i) in case the Issuer shall consolidate with or
         merge into another person or convey, transfer or lease its properties
         and assets substantially as an entirety to any person, the person
         formed by such consolidation or into which the Issuer is merged or the
         person which acquires by conveyance or transfer, or which leases, the
         properties and assets of the Issuer substantially as an entirety shall
         be a corporation, partnership or trust, shall be organized and validly
         existing under the laws of the United States of America, any State
         thereof or the District of Columbia (the "Successor Person") and shall
         expressly assume, by amendment to the Fiscal Agency Agreement signed by
         the Issuer and such Successor Person and delivered to the Fiscal Agent,
         the due and punctual payment of the principal of an interest on all the
         Securities and the performance or observance of every covenant hereof
         and of the Fiscal Agency Agreement on the part of the Issuer to be
         performed or observed;

                                      A-9

<PAGE>

                           (ii) immediately after giving effect to such
         transaction and treating any indebtedness which becomes an obligation
         of the Issuer or any Subsidiary of it as a result of such transaction
         as having been incurred by the Issuer or any such Subsidiary at the
         time of such transaction, no event of default ( as set forth in
         Paragraph 5), and no event which, with notice or lapse of time or both,
         would become such an event of default, shall have happened and be
         continuing;

                           (iii) if, as a result of any such consolidation or
         merger or such conveyance, transfer or lease, properties or assets of
         the Issuer or any Subsidiary of it would become subject to a mortgage,
         pledge, lien, security interest or other encumbrance which would not be
         permitted by Paragraph 7 hereof, the Issuer, or the Successor Person,
         as the case may be, shall take such steps as shall be necessary
         effectively to secure the Securities equally and ratably with (or prior
         to) all Indebtedness secured by such mortgage, pledge, lien, security
         interest or other encumbrance; and

                           (iv) the Issuer has delivered to the Fiscal Agent an
         Officers' Certificate and a written opinion or opinions of counsel
         satisfactory to the Fiscal Agent (who may be counsel to the Issuer),
         stating that such consolidation, merger, conveyance, transfer or lease
         and such amendment to the Fiscal Agency Agreement comply with this
         Paragraph 8 and that all conditions precedent herein provided for
         relating to such transaction have been complied with.

                  (b)   Upon any such consolidation or merger, or any
conveyance, transfer or lease of the properties and assets of the Issuer
substantially as an entirety in accordance with Paragraph 8(a), the Successor
Person shall succeed to, and be substituted for, and may exercise every right
and power of the Issuer under the Fiscal Agency Agreement and the Securities
with the same effect as if the Successor Person had been named as the Issuer in
the Fiscal Agency Agreement and the Securities, and thereafter the Issuer,
except in the case of a lease of its properties and assets, shall be released
from its liability as obligor on any of the Securities and under the Fiscal
Agency Agreement.

9.      Section 7 of the Fiscal Agency Agreement, which requires the Issuer
to provide registered holders of Securities or, in the case of clauses (a) and
(b) thereof, designated prospective purchasers of Securities with certain
information and an Officers' Certificate, is hereby incorporated mutatis
mutandis by reference herein.

10.     Until the date that is two years from the date of original issuance
of the Securities, the Issuer will not, and will not permit any of its
"affiliates" (as defined under Rule 144 under the Act or any successor provision
thereto) to, resell any Securities which constitute "restricted securities"
under Rule 144 that have been reacquired by any of them.

11.     If any mutilated Security is surrendered to the Fiscal Agent, the
Issuer shall execute, and the Fiscal Agent shall authenticate and deliver in
exchange therefor, a new Security of like tenor and principal amount, bearing a
number not contemporaneously outstanding.

         If there be delivered to the Issuer and the Fiscal Agent (i) evidence
to their satisfaction of the destruction, loss or theft of any Security and (ii)
such security or indemnity as may be required by them to save each of them and
any agent of each of them harmless, then, in the absence of notice to the Issuer
or the Fiscal Agent that such Security has been acquired by a bona fide
purchaser, the Issuer shall execute, and upon its request the Fiscal Agent shall
authenticate and deliver in lieu of any such destroyed, lost or stolen Security
a new Security of like tenor and principal amount and bearing a number not
contemporaneously outstanding.

         Upon the issuance of any new Security under this Paragraph, the Issuer
may require the payment of a sum sufficient to cover any tax or other
governmental charge that may be imposed in relation thereto and any other
expenses (including the fees and the expenses of the Fiscal Agent) connected
therewith.

         Every new Security issued pursuant to this Paragraph in lieu of any
destroyed, lost or stolen Security, shall constitute an original additional
contractual obligation of the Issuer, whether or not the destroyed, lost or
stolen Security shall be at any time enforceable by anyone.

                                      A-10
<PAGE>

         Any new Security delivered pursuant to this Paragraph shall be so dated
that neither gain nor loss in interest shall result from such exchange.

         The Provisions of this Paragraph 11 are exclusive and shall preclude
(to the extent lawful) all other nights and remedies with respect to the
replacement or payment of mutilated, destroyed, lost or stolen Securities.

12.     Section 11 of the Fiscal Agency Agreement, which Section is hereby
incorporated mutatis mutandis by reference herein, provides that, with certain
exceptions as therein provided and by written consent of a majority in the
principal amount of all Outstanding Securities, the Issuer and the Fiscal Agent
may modify, amend or supplement the Fiscal Agency Agreement or the terms of the
Securities or may give consents or waivers or take other actions with respect
thereto. Any such modification, amendment, supplement, consent, waiver, or other
action shall be conclusive and binding on the holder of this Security and on all
future holders of this Security and of any Security issued upon the registration
of transfer hereof or in exchange heretofore or in lieu hereof, whether or not
notation thereof is made upon this Security. The Fiscal Agency Agreement and the
terms of the Securities may be modified or amended by the Issuer and the Fiscal
Agent, without the consent of any holders of Securities, for the purpose of (i)
adding to the covenants of the Issuer for the benefit of the holders of
Securities, or (ii) surrendering any right or power conferred upon the Issuer,
or (iii) securing the Securities pursuant to the requirements of the Securities
or otherwise, or (iv) evidencing the succession of another corporation to the
Issuer and the assumption by any such successor of the covenants and obligations
of the Issuer in the Securities or in the Fiscal Agency Agreement pursuant to
Paragraph 8 hereof, or (v) correcting or supplementing any defective provision
contained in the Securities or in the Fiscal Agency Agreement, to all of which
each holder of any Security, by acceptance thereof, consents.

13.     No reference herein to the Fiscal Agency Agreement and no provision
of this Security or of the Fiscal Agency Agreement shall alter or impair the
obligation of the Issuer, which is absolute and unconditional, to pay the
principal of and interest on this Security at the times, place and rate, and in
the coin or currency, herein prescribed.

14.     This Security is subject to the provisions of Section 14 of the
Fiscal Agency Agreement (which are incorporated mutatis mutandis by reference
herein) which provide for the defeasance at any time of (i) the entire
indebtedness of this Security or (ii) certain covenants and events of default,
in each case upon compliance with certain conditions set forth therein.

15.     THIS SECURITY SHALL BE GOVERNED BY AND CONSTRUED IN ACCORDANCE WITH
THE LAWS OF THE STATE OF NEW YORK.

                                      A-11

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