CONTRIBUTION AGREEMENT

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                                                                     Exhibit 2.1

                                                                  EXECUTION COPY

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                             CONTRIBUTION AGREEMENT

                                  by and among

                                   ONEOK, INC.

                         NORTHERN BORDER PARTNERS, L.P.

                                       and

                NORTHERN BORDER INTERMEDIATE LIMITED PARTNERSHIP

                                February 14, 2006

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                                TABLE OF CONTENTS

<TABLE>
<S>                                                                           <C>
SECTION 1.  CONTRIBUTION...................................................    1
   1.1      Contribution to Northern Border................................    1
   1.2      Issuance of the Units..........................................    2
   1.3      The Closing....................................................    2
   1.4      GP Contribution and Dropdown To NBILP..........................    3
   1.5      Working Capital Adjustment.....................................    3

SECTION 2.  REPRESENTATIONS AND WARRANTIES OF ONEOK........................    5
   2.1      Organization and Authority of ONEOK............................    5
   2.2      Organization, Authority and Qualification of the Entities......    6
   2.3      Capital of Companies; Beneficial Ownership.....................    6
   2.4      Subsidiaries...................................................    7
   2.5      Financial Statements...........................................    7
   2.6      Taxes..........................................................    8
   2.7      Absence of Certain Changes.....................................    9
   2.8      Ordinary Course................................................   10
   2.9      Intellectual Property..........................................   10
   2.10     Contracts......................................................   11
   2.11     Compliance.....................................................   12
   2.12     Litigation.....................................................   12
   2.13     Insurance......................................................   12
   2.14     Related Transactions...........................................   13
   2.15     Employee Benefit Matters.......................................   13
   2.16     Environmental Matters..........................................   14
   2.17     Securities Act.................................................   14
   2.18     Regulatory Matters.............................................   15
   2.19     Operating Assets...............................................   15
   2.20     Brokers' Fees..................................................   16
   2.21     Books and Records..............................................   16
   2.22     Indebtedness...................................................   16
   2.23     Disclaimer.....................................................   16

SECTION 3.  REPRESENTATIONS AND WARRANTIES OF THE NBP PARTNERSHIPS.........   17
   3.1      Organization and Authority of the NBP Partnerships.............   17
   3.2      Capitalization.................................................   18
   3.3      Litigation.....................................................   19
   3.4      Compliance.....................................................   19
   3.5      Employee Matters...............................................   19
   3.6      Environmental Matters..........................................   20
   3.7      Absence of Certain Changes.....................................   21
   3.8      Securities Act.................................................   21
   3.9      SEC Filings....................................................   21
   3.10     Brokers' Fees..................................................   22
   3.11     Opinion of Financial Adviser...................................   22
</TABLE>

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<TABLE>
<S>                                                                           <C>
   3.12     Registration Rights............................................   22
   3.13     Disclaimer.....................................................   22

SECTION 4.  COVENANTS OF ONEOK.............................................   23
   4.1      Conduct of the Entities........................................   23
   4.2      Cash Management................................................   25

SECTION 5.  COVENANTS OF THE NBP PARTNERSHIPS..............................   25
   5.1      Books and Records..............................................   25
   5.2      Approval of Issuance of Common Units Upon Conversion Units.....   26

SECTION 6.  COVENANTS OF ONEOK AND THE NBP PARTNERSHIPS....................   26
   6.1      Access to Information..........................................   26
   6.2      Commercially Reasonable Efforts................................   27
   6.3      Regulatory and Other Authorizations; Notices and Consents......   27
   6.4      Public Announcements...........................................   28
   6.5      Notices of Certain Events......................................   29
   6.6      Entity Guarantees..............................................   29
   6.7      Intercompany Accounts..........................................   29
   6.8      Shared Contracts and Drop-Down Contracts.......................   29
   6.9      ONEOK Marks....................................................   30
   6.10     Indebtedness for Borrowed Money................................   31
   6.11     Conversion Transactions........................................   31
   6.12     Interim Financial Statements...................................   31
   6.13     Cooperation Regarding Audits...................................   31
   6.14     Insurance Matters..............................................   32

SECTION 7.  CONDITIONS TO CLOSING..........................................   32
   7.1      Conditions to the Obligations of ONEOK.........................   32
   7.2      Conditions to the Obligations of the NBP Partnerships..........   34

SECTION 8.  TERMINATION OF AGREEMENT; RIGHTS TO PROCEED....................   36
   8.1      Termination....................................................   36
   8.2      Effect of Termination..........................................   37

SECTION 9.  INDEMNIFICATION................................................   37
   9.1      Survival of Representations and Warranties, Etc................   37
   9.2      Indemnification................................................   37
   9.3      Threshold; Cap.................................................   38
   9.4      Exclusive Remedy; Sole Recourse................................   40
   9.5      No Contribution................................................   40
   9.6      Setoff.........................................................   40
   9.7      Third Party Claims.............................................   40

SECTION 10. TAX MATTERS....................................................   41
   10.1     Retention of Records...........................................   41
   10.2     Cooperation....................................................   41
</TABLE>


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<TABLE>
<S>                                                                           <C>
   10.3     Transfer Taxes.................................................   42
   10.4     Tax Returns....................................................   42
   10.5     Allocation of Taxes............................................   43
   10.6     Tax Indemnity..................................................   45
   10.7     Contests.......................................................   46
   10.8     Amended Tax Returns............................................   47
   10.9     Miscellaneous..................................................   47
   10.10    Allocation of Value among the Contributed Entities; Book Ups...   47

SECTION 11. MISCELLANEOUS..................................................   48
   11.1  Fees and Expenses.................................................   48
   11.2  Governing Law.....................................................   48
   11.3  Notices...........................................................   48
   11.4  Entire Agreement..................................................   50
   11.5  Assignability; Binding Effect.....................................   50
   11.6  Captions and Gender...............................................   50
   11.7  Execution in Counterparts.........................................   50
   11.8  Amendments........................................................   50
   11.9  Publicity and Disclosures.........................................   50
   11.10 Severability......................................................   51
   11.11 Waiver of Jury Trial..............................................   51
   11.12 Arbitration.......................................................   51
   11.13 Time of the Essence...............................................   51
   11.14 Remedies Cumulative; Specific Performance.........................   51
   11.15 Further Assurances................................................   52
   11.16 Third Party Beneficiaries.........................................   52
   11.17 Audit Committee Authority.........................................   52
   11.18 Certain Definitions...............................................   52
   11.19 Other Defined Terms...............................................   60
</TABLE>

Exhibit A - Companies/Company Subsidiaries
Exhibit B - Form of Amendment
Exhibit C - ONEOK Guaranty Agreement
Exhibit D - Target Working Capital
Exhibit E - Services Agreement


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                             CONTRIBUTION AGREEMENT

     This CONTRIBUTION AGREEMENT (this "Agreement") is entered into as of
February 14, 2006 by and among ONEOK, Inc., an Oklahoma corporation ("ONEOK"),
Northern Border Partners, L.P., a Delaware limited partnership ("Northern
Border"), and Northern Border Intermediate Limited Partnership ("NBILP", and
together with Northern Border, the "NBP Partnerships ") (each a "Party" and
together, the "Parties"). Capitalized terms used but not defined shall have the
meaning given in Section 11.18.

                                   WITNESSETH

     WHEREAS, ONEOK owns all of the issued and outstanding Equity Interests (the
"Shares") of each of the Persons listed on Exhibit A hereto under the heading
"Companies" (the "Companies", and each, individually, a "Company");

     WHEREAS, the Companies and their Subsidiaries, all of which are listed on
Exhibit A under the heading "Company Subsidiaries", own and operate natural gas
gathering, processing, fractionating, transportation, storage, pipelines and
natural gas liquids assets located in Kansas, Oklahoma and Texas (the
"Business"); and

     WHEREAS, ONEOK wishes to contribute the Shares to the NBP Partnerships and
the NBP Partnerships wish to accept the contribution of the Shares, upon the
terms and conditions set forth herein.

     NOW, THEREFORE, in consideration of the premises and mutual agreements and
covenants herein contained, and intending to be legally bound hereby, the
Parties hereto hereby agree as follows:

SECTION 1. CONTRIBUTION

          1.1 CONTRIBUTION TO NORTHERN BORDER. Immediately before Closing, ONEOK
shall deliver or cause to be delivered to Northern Plains Natural Gas Company,
LLC ("Northern Plains") and Pan Border Gas Company, LLC ("Pan Border", and
collectively, the "Contributing NBP General Partners"), good and sufficient
instruments of transfer transferring the NBP GP Shares and the NBILP GP Shares
to the Contributing NBP General Partners. At the Closing, ONEOK and the
Contributing NBP General Partners shall deliver or cause to be delivered to
Northern Border good and sufficient instruments of transfer transferring the NBP
Shares and the NBP GP Shares, respectively, to Northern Border. Such instruments
of transfer shall effectively vest in Northern Border good and marketable title
to the NBP Shares and the NBP GP Shares free and clear of all Liens other than
transfer restrictions imposed by applicable securities laws. The contribution of
the NBP GP Shares by the Contributing NBP General Partners will be made in order
to comply with the NBP General Partners' obligations to maintain general partner
capital accounts in accordance with Section 4.2 of the Northern Border
Partnership Agreement and NBP acknowledges that the contribution of the NBP GP
Shares by the Contributing NBP general Partners is sufficient to maintain the
aggregate general partner capital accounts in NBP required by Section 4.2 of the
Northern Border Partnership Agreement.

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          1.2 ISSUANCE OF THE UNITS. As consideration for the NBP Shares,
Northern Border will, at Closing, issue to ONEOK 36,494,126 units representing
limited partnership interests in Northern Border with the rights and preferences
contained in the form of amendment (the "Amendment") to the Amended and Restated
Agreement of Limited Partnership of Northern Border, dated as of October 1, 1993
(the "Northern Border Partnership Agreement"), attached hereto as Exhibit B (the
"Units"), which Units shall be convertible, as set forth in the Amendment, into
common units representing limited partnership interests in Northern Border
("Common Units;" and the Common Units into which the Units are convertible, the
"Conversion Units").

          1.3 THE CLOSING.

               (a) Subject to the provisions of Section 8, the closing of the
transactions contemplated by this Agreement (the "Closing") shall take place at
the offices of Gable & Gotwals, 100 W. 5th Street, Tulsa, OK 74103, commencing
at 10:00 a.m. local time on the first business day of the calendar month
immediately following the satisfaction or waiver of all conditions to the
obligations of the Parties to consummate the transactions contemplated hereby
(other than conditions with respect to actions the Parties shall take at the
Closing itself, including without limitation, conditions in Section 7.1(h) and
7.2(h) herein) or such other date as Northern Border and ONEOK may mutually
determine (the "Closing Date").

               (b) At the Closing, ONEOK will deliver the following documents
and deliverables to Northern Border:

                    (i) Good and sufficient instruments of transfer transferring
all of the Shares to Northern Border free and clear of all Liens other than
transfer restrictions imposed by applicable securities laws;

                    (ii) An executed copy of a Services Agreement substantially
in the form attached hereto as Exhibit E (the "Services Agreement");

                    (iii) A certificate certifying that the transactions
contemplated hereby are exempt from withholding under Code Section 1445 executed
in accordance with the requirements of the Treasury regulations promulgated
thereunder;

                    (iv) Resignations of the officers, directors and managers
identified prior to Closing by Northern Border;

                    (v) An executed copy of a Guaranty substantially in the form
attached hereto as Exhibit C (the "ONEOK Guaranty Agreement");

                    (vi) An executed copy of a Payment, Performance, Indemnity
and Support Agreement substantially in the form attached hereto as Schedule
1.3(b)(vi);

                    (vii) A written opinion from legal counsel to ONEOK
addressed to Northern Border substantially in the form attached hereto as
Schedule 1.3(b)(vii); and


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                    (viii) Such other certificates, instruments of conveyance,
and documents as may be reasonably requested by Northern Border prior to the
Closing Date to carry out the intent and purposes of this Agreement.

               (c) At the Closing, Northern Border will deliver the following
documents and deliverables to ONEOK:

                    (i) Certificates (or appropriate evidence of a book entry
transfer to the account designated by ONEOK) representing the Units;

                    (ii) An executed copy of the Services Agreement;

                    (iii) An Agreement and Guaranty with respect to each of the
equipment leases relating to ONEOK Bushton Processing, Inc., in a form
reasonably acceptable to ONEOK and Northern Border, and such other agreements,
certificates and assurances necessary in connection with the transfer of ONEOK
Bushton Processing, Inc. to Northern Border;

                    (iv) An executed copy of a Payment, Performance, Indemnity
and Support Agreement substantially in the form attached hereto as Schedule
1.3(b)(vi);

                    (v) A written opinion from legal counsel to Northern Border
addressed to ONEOK substantially in the form attached hereto as Schedule
1.3(c)(v); and

                    (vi) Such other certificates, instruments, and documents as
may be reasonably requested by ONEOK prior to the Closing Date to carry out the
intent and purposes of this Agreement.

          1.4 GP CONTRIBUTION AND DROPDOWN TO NBILP. At the Closing and
immediately following the contribution set forth in Section 1.1, (i) Northern
Border shall deliver to NBILP good and sufficient instruments of transfer
transferring the NBP Shares and the NBP GP Shares to NBILP, and (ii) ONEOK shall
cause the Contributing NBP General Partners to deliver to NBILP good and
sufficient instruments of transfer transferring the NBILP GP Shares to NBILP.
Such instruments of transfer shall effectively vest in NBILP good and marketable
title to the Shares free and clear of all Liens other than transfer restrictions
imposed by applicable securities laws. The contribution of the NBILP GP Shares
by the Contributing NBP General Partners will be made in order to comply with
the NBP General Partners' obligations to maintain general partner capital
accounts in accordance with Section 4.2 of the Amended and Restated Agreement of
Limited Partnership of NBILP, dated as of October 1, 1993 (the "NBILP
Partnership Agreement") and NBILP acknowledges that the contribution of the
NBILP GP Shares by the Contributing NBP General Partners is sufficient to
maintain the aggregate general partner capital accounts in NBILP required by
Section 4.2 of the NBILP Partnership Agreement.

          1.5 WORKING CAPITAL ADJUSTMENT.

               (a) As soon as practicable, but in no event later than 60 days
following the Closing, ONEOK shall prepare and deliver to Northern Border a
calculation (the "Closing Working Capital Statement") of the Net Working Capital
of the Entities, on a consolidated basis,


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as of the close of business on the last day of the month immediately preceding
the Closing Date (the "Closing Working Capital"). The Closing Working Capital
Statement shall be prepared in accordance with the principles set forth in the
definition of Net Working Capital.

               (b) ONEOK shall deliver a copy of the Closing Working Capital
Statement to Northern Border promptly after it has been prepared. After receipt
of the Closing Working Capital Statement, Northern Border shall have 30 days to
review the Closing Working Capital Statement, together with the work papers used
in the preparation thereof. ONEOK shall (i) provide Northern Border and its
Representatives reasonable access during normal business hours to all relevant
personnel, work papers, trial balances and other financial information to the
extent necessary or useful to complete their review of the Closing Working
Capital Statement, and (ii) cooperate with Northern Border's and its
Representatives' reasonable requests with respect to the review of the Closing
Working Capital Statement, including by providing on a timely basis all
information necessary or useful in reviewing the Closing Working Capital
Statement. Unless Northern Border delivers written notice to ONEOK on or prior
to the 30th day after Northern Border's receipt of the Closing Working Capital
Statement specifying in reasonable detail the amount, nature and basis of all
disputed items, Northern Border shall be deemed to have accepted and agreed to
the calculation of the Closing Working Capital. If Northern Border (or one of
its Representatives) notifies ONEOK of an objection to the calculation of the
Closing Working Capital, ONEOK and Northern Border shall, within 20 days (or
such longer period as the Parties may agree in writing) following such notice
(the "Resolution Period"), attempt to resolve their differences and any
resolution by them as to any disputed amounts shall be final, binding and
conclusive (other than as a result of manifest error or fraud).

               (c) If, at the conclusion of the Resolution Period, there are any
amounts remaining in dispute, then such amounts remaining in dispute shall be
submitted to a nationally recognized public accounting firm agreed by Northern
Border and ONEOK (the "Neutral Auditors"). Northern Border and ONEOK shall
execute, if requested by the Neutral Auditors, a reasonable engagement letter,
including customary indemnities. The Neutral Auditors shall act as an arbitrator
to determine, based solely on the provisions of this Section 1.5(c) and the
presentations by ONEOK and Northern Border, and not by independent review, only
those issues still in dispute. The Neutral Auditors' determination shall be made
within 30 days of the dispute being submitted for their determination, shall be
set forth in a written statement delivered to ONEOK and Northern Border and
shall be final, non-appealable and binding on the Parties hereto, absent
manifest error or fraud. A judgment of a court of competent jurisdiction may be
entered upon the Neutral Auditors' determination. The Neutral Auditors shall
have exclusive jurisdiction over, and resort to the Neutral Auditors as provided
in this Section 1.5(c) shall be the only recourse and remedy of the Parties
against one another with respect to, any disputes arising out of or relating to
the adjustments pursuant to this Section 1.5(c). The fees, costs and expenses of
the Neutral Auditors shall be borne by Northern Border, on the one hand, and by
ONEOK, on the other, based upon the percentage which the portion of the
contested amount not awarded to each Party bears to the amount actually
contested by such Party. For example, if Northern Border claims that the Closing
Working Capital is $1,000 less than the amount determined by ONEOK, and ONEOK
contests only $500 of the amount claimed by Northern Border, and if the Neutral
Auditors ultimately resolve the dispute by awarding Northern Border $300 of the
$500 contested, then the costs and expenses of the Neutral Auditors will be
allocated 60% (i.e., 300 / 500) to ONEOK and 40% (i.e., 200 / 500) to Northern
Border. The term "Final Closing


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Working Capital" shall mean the definitive Closing Working Capital agreed to (or
deemed to be agreed to) by Northern Border and ONEOK in accordance with Section
1.5(b) hereof or resulting from the determinations made by the Neutral Auditors
in accordance with this Section 1.5(c) (in addition to those items theretofore
agreed to by ONEOK and Northern Border).

               (d) In the event the Final Closing Working Capital

                    (i) exceeds the Target Working Capital, Northern Border
shall pay the excess in cash to ONEOK; or

                    (ii) is less than the Target Working Capital, ONEOK shall
pay the difference in cash to Northern Border (the payments contemplated by this
Section 1.5(d) are referred to as the "Net Working Capital Adjustment").

     All payments made pursuant to this Section 1.5 shall be made by wire
transfer of immediately available funds within five (5) days of the
determination of the Final Closing Working Capital to an account designated in
writing by the applicable Party.

SECTION 2. REPRESENTATIONS AND WARRANTIES OF ONEOK

     Except as set forth in the disclosure schedules delivered by ONEOK (the
"ONEOK Disclosure Schedules") to Northern Border on the date hereof (it being
agreed that any matter disclosed in a particular Schedule of the Disclosure
Schedules delivered by ONEOK shall be deemed to have been disclosed with respect
to any other Sections of this Agreement to the extent that the relevance of such
matter to such other Section is readily apparent from the information
disclosed), ONEOK represents and warrants to Northern Border that the statements
contained in this Section 2 are true, correct and complete as of the date of
this Agreement and will be true, correct and complete as of the Closing, except
in each case to the extent that such statements are expressly made only as of a
specified date, in which case ONEOK represents and warrants that such statements
are true, correct and complete as of such specified date.

          2.1 ORGANIZATION AND AUTHORITY OF ONEOK.

               (a) ONEOK is a corporation duly incorporated, validly existing
and in good standing under the laws of Oklahoma.

               (b) ONEOK has all requisite right, authority and power to enter
into this Agreement and each Related Agreement to be executed and delivered by
ONEOK and to carry out the transactions contemplated hereby and thereby.

               (c) The execution, delivery and performance by ONEOK of this
Agreement and each Related Agreement have been duly authorized by all necessary
action of ONEOK and no other action on the part of ONEOK is required in
connection therewith.

               (d) This Agreement and each Related Agreement to be executed and
delivered by ONEOK constitutes, or when executed and delivered will constitute,
valid and binding obligations of ONEOK enforceable in accordance with their
respective terms, except as such


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enforceability may be limited by bankruptcy, insolvency or other similar laws
from time to time in effect which affect the enforcement of creditors' rights
generally.

               (e) The execution, delivery and performance by ONEOK of this
Agreement and each Related Agreement to be executed and delivered by ONEOK, with
or without the giving of notice or the passage of time, or both:

                    (i) do not and will not conflict with or violate any
provision of the organizational documents of ONEOK or any Entity;

                    (ii) do not and will not conflict with or violate any Legal
Requirements applicable to ONEOK or any of the Entities, or, except as set forth
in Schedule 2.1(e)(ii) and any filings required to be made under the HSR Act,
require ONEOK or any Entity to obtain any approval, consent or waiver of, or
make any filing with, any Governmental Authority that has not been obtained or
made;

                    (iii) do not and will not require the consent, approval or
waiver of any Person (other than any Governmental Authority), except as set
forth in Schedule 2.1(e)(iii), or except for any such consents, approvals or
waivers as have been obtained or the failure of which to be obtained would not,
individually or in the aggregate, have a Material Adverse Effect; and

                    (iv) does not and will not breach any Material Contract or
result in or permit the termination of any such Material Contract.

          2.2 ORGANIZATION, AUTHORITY AND QUALIFICATION OF THE ENTITIES. Each
Company and each Subsidiary thereof (each, a "Company Subsidiary" and, together
with the Companies, each an "Entity" and, collectively, the "Entities") is duly
organized, validly existing and in good standing under the laws of the
jurisdiction of its organization, as set forth on Exhibit A, and has all
necessary power and authority to own, operate or lease the properties and assets
now owned, operated or leased by it and to carry on its business as it is
currently conducted. Each Entity is duly licensed or qualified to do business
and is in good standing (to the extent applicable) in each jurisdiction in which
the properties owned or leased by it or the operation of its business makes such
licensing or qualification necessary, except where the failure to be so
qualified or licensed would not, individually or in the aggregate, have a
Material Adverse Effect. All material actions taken by the Entities have been
duly authorized, and no Entity has taken any action that in any material respect
conflicts with, constitutes a material default under or results in a material
violation of the organizational documents of such Entities. True and correct
copies of the organizational documents of each Entity, each as in effect on the
date hereof, have previously been made available to Northern Border.

          2.3 CAPITAL OF COMPANIES; BENEFICIAL OWNERSHIP.

               (a) All of the issued and outstanding shares of capital stock of
each of the Companies that is a corporation are validly issued, fully paid and
nonassessable and are owned beneficially and of record, directly or indirectly,
by ONEOK, and all of the limited liability company interests in each of the
Companies that is a limited liability company are validly issued, fully paid and
nonassessable and are owned beneficially and of record, directly or indirectly,
by ONEOK, in each case free and clear of all Liens.


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               (b) There are no outstanding options, warrants, rights,
commitments, preemptive rights or agreements of any kind for the issuance or
sale of, or outstanding securities convertible into, any additional shares of
capital stock of any class or limited liability company interests, as the case
may be, of any Company which would entitle the holders thereof to an interest in
or rights in respect of that Company, and there are no agreements of any kind
that may obligate ONEOK or any of its Affiliates (including the Companies) to
sell, issue, purchase, redeem or otherwise transfer any Shares to any Person.
There are no voting agreements, proxies or other similar agreements or
understandings with respect to the Shares.

          2.4 SUBSIDIARIES.

               (a) Exhibit A lists, for each Company Subsidiary, its name, type
of entity, jurisdiction of its incorporation, formation or organization and the
percentage Equity Interest owned by a Company. Except as set forth in Schedule
2.4(a), the Companies own, directly or indirectly, all of the issued and
outstanding Equity Interests of each Company Subsidiary, free and clear of all
Liens other than transfer restrictions imposed by applicable securities laws,
and the owner beneficially and of record of each Company Subsidiary is either a
Company or a Company Subsidiary, as applicable, and all Equity Interests of each
Company Subsidiary are validly issued, fully paid and nonassessable. There are
no options, warrants, convertible securities or other rights, agreements,
arrangements or commitments of any character relating to the Equity Interests of
the Company Subsidiaries or that may obligate the Company Subsidiaries to issue
or sell any Equity Interests of any Company Subsidiary, and there are no
agreements of any kind that may obligate any Company to sell, issue, purchase,
redeem or otherwise transfer any Equity Interests in any Company Subsidiary to
any Person. There are no voting agreements, proxies or other similar agreements
or understandings with respect to the Equity Interests of the Company
Subsidiaries.

               (b) Other than the Company Subsidiaries, no Entity owns any
Equity Interest in any Person except as set forth in Schedule 2.4(b). The
Entities own, directly or indirectly, 50% of the outstanding Equity Interests in
Fox Plant, L.L.C. and 10.1765% of the Equity Interests in Venice Energy Services
Company, L.L.C., in each case free and clear of all Liens, other than transfer
restrictions imposed by applicable securities laws.

          2.5 FINANCIAL STATEMENTS.

               (a) ONEOK has delivered to Northern Border true, correct and
complete copies of a consolidated unaudited balance sheet of the Entities (the
"Balance Sheet") as of December 31, 2005 (the "Balance Sheet Date") and an
unaudited statement of income of the Acquired Entities for the 12 months then
ended (together, the "Financial Statements") copies of which are attached hereto
as Schedule 2.5(a). The long-term Indebtedness listed in the Financial
Statements under the caption "Long-term Debt, excluding current maturities" is
all owed to ONEOK or its Affiliates.

               (b) Except (i) to the extent set forth in or reserved against in
the Balance Sheet or as identified in Schedule 2.5(b) hereto, (ii) for current
liabilities (determined in accordance with GAAP) incurred in the ordinary course
of business consistent with past practices since the Balance Sheet Date, and
(iii) for immaterial Liabilities, none of the Entities has any Liabilities of


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the type that would be required to be disclosed on a balance sheet of that
Entity (or the notes thereto) prepared in accordance with GAAP.

               (c) The Financial Statements have been prepared in accordance
with GAAP (except as disclosed herein) during the periods covered thereby, are
complete and correct in all material respects, and present fairly in all
material respects the financial condition of the applicable Entities at the
dates of said statements and the results of their operations for the periods
covered thereby, except for normal year or period end adjustments and the
absence of footnotes.

          2.6 TAXES.

               (a) The Entities have (giving effect to extensions) (x) duly and
timely filed (or there has been filed on their behalf) with the appropriate
Governmental Authority all income and other material Tax Returns required to be
filed by them, and all such Tax Returns are true, correct and complete in all
material respects and (y) timely paid or accrued on the their books, or there
has been paid on their behalf, all material Taxes due and payable.

               (b) The Entities have complied in all material respects with all
applicable Tax Laws relating to the payment and withholding of Taxes.

               (c) There are no Liens that arose in connection with Taxes upon
the assets or properties of the Entities except for Liens described in clause
(a) of the definition of "Permitted Liens".

               (d) The Entities have not requested (nor has any request been
made by any Person on behalf of any of the Entities) in writing any extension of
time within which to file any Tax Return in respect of any taxable year which
has not since been filed, and no outstanding written waivers or comparable
written consents regarding the application of the statute of limitations with
respect to any Taxes or Tax Returns has been given by or on behalf of the
Entities.

               (e) To the Knowledge of ONEOK, no U.S. federal, state, local or
foreign audits, reviews or other administrative proceedings or court proceedings
("Audits") are ongoing or have been initiated with regard to any Taxes or Tax
Returns of the Entities, and the Entities have not received any written notice
of any such Audits.

               (f) None of the Entities has agreed or is required to make any
adjustment by reason of a change in accounting method that would affect any
taxable year ending after the Closing Date, and no Tax Authority has proposed
any such adjustment or change in accounting method that would affect any taxable
year ending after the Closing Date. None of the Entities have an application
pending with any Tax Authority requesting permission for any change in
accounting method that relates to their business or operations and that would
affect any taxable year ending after the Closing Date.

               (g) Each of the Entities is classified as a partnership or a
disregarded entity for U.S. federal income tax purposes, except for those
Entities listed in Schedule 2.6.


                                       8

<PAGE>

               (h) No written claim has been made, and to the Knowledge of ONEOK
there has been no oral or threatened claim, by any Tax Authority in a
jurisdiction where an Entity does not file a Tax Return that it is or may be
subject to Tax in that jurisdiction.

               (i) None of the Entities is a party to any Tax allocation or
sharing agreement or has any liability for the Taxes of another Person under
Treasury Regulations Section 1.1502-6 or similar law, as a transferee,
successor, by contract or otherwise.

               (j) ONEOK is a United States person within the meaning of the
Code.

               (k) The unpaid Taxes of the Companies (A) did not, as of the
Balance Sheet Date, exceed the reserves established on the Financial Statements,
and (B) do not exceed the reserve as adjusted for the passage of time through
the Closing Date in accordance with past custom and practice of the Entities in
filing their Tax Returns.

               (l) None of the assets or properties of the Entities (A) secures
any debt the interest on which is tax-exempt under Code Section 103(a), (B) is
"tax-exempt use property" within the meaning of Code Section 168(h), (C) is "tax
exempt bond financed property" within the meaning of Code Section 168(g)(5), (D)
is "limited use property" within the meaning of Revenue Procedure 76-30 or (E)
will be treated as owned by another Person pursuant to the provisions of Code
Section 168(f)(8).

               (m) The transactions contemplated herein are not subject to tax
withholding pursuant to the provisions of Section 3406 or Subchapter A of
Chapter 3 of the Code or any other Legal Requirement.

          2.7 ABSENCE OF CERTAIN CHANGES. As of the date hereof, except as
identified on Schedule 2.7, since the Balance Sheet Date there has not been:

               (a) any change in the financial condition, properties, assets,
Liabilities, business or operations of the Entities that has had or would
reasonably be expected to have, individually or in the aggregate, a Material
Adverse Effect;

               (b) any contingent Liability incurred by any of the Entities as
guarantor or otherwise with respect to the obligations of others (other than any
other Entity) in excess of $500,000, or any cancellation of any material debt or
claim owing to any Entity, or waiver of any right that has had or would
reasonably be expected to have, individually or in the aggregate, a Material
Adverse Effect;

               (c) other than Permitted Liens, any Lien placed on any of the
material properties of the Entities, that remain in existence on the date hereof
and that will remain in existence on the Closing Date;

               (d) any material obligation or Liability of any nature incurred
by any of the Entities, whether accrued, absolute, contingent or otherwise,
asserted or unasserted, known or unknown, other than obligations and Liabilities
incurred in the ordinary course of business consistent with past practice and in
accordance with the terms of this Agreement;


                                       9

<PAGE>

               (e) any purchase, sale or other disposition, or any agreement or
other arrangement for the purchase, sale or other disposition, of any of the
material properties or assets of any Entity other than in the ordinary course of
business consistent with past practice and in accordance with the terms of this
Agreement;

               (f) any material change in accounting principles, methods or
practices used by any Entity;

               (g) any loss, damage, destruction or other casualty to any
Entity's property, plants, equipment or inventories (whether or not covered by
insurance) that has had or would reasonably be expected to have, individually or
in the aggregate, a Material Adverse Effect;

               (h) any material change in the compensation levels of any
Entity's senior executives, any material changes in the manner in which other
employees are generally compensated or any provision of additional or
supplemental benefits for its employees generally, except, in each case, normal
periodic increases or promotions effected in the ordinary course of business
consistent with past practice;

               (i) any material commitment, guarantee, contractual obligation,
capital expenditure or transaction entered into by any Entity, other than in the
ordinary course of business consistent with past practice, or any borrowing or
other incurrence, assumption or guarantee of Indebtedness by any Entity other
than short term Indebtedness owed to ONEOK or its Affiliates; or

               (j) any agreement or understanding whether in writing or
otherwise, for any Entity to take any of the actions specified in paragraphs (a)
through (i) above.

     For purposes of this Section 2.7, materiality, as to any matter, shall be
determined with respect to all the Entities, taken as a whole.

          2.8 ORDINARY COURSE. Since the Balance Sheet Date, the Entities have
conducted their respective businesses in the ordinary course of business
consistent with past practices.

          2.9 INTELLECTUAL PROPERTY. Each Entity owns or has the right to use
all Intellectual Property Assets necessary for or used in the conduct of its
business as currently conducted ("Entity Intellectual Property Assets"), and all
such Entity Intellectual Property Assets owned by any Entity are free and clear
of all Liens (other than Permitted Liens). Neither the execution or delivery of
this Agreement, nor the consummation of the transactions contemplated hereby
will, with or without notice or lapse of time, result in, or give any other
Person the right or option to cause or declare, a breach or termination of, or
cancellation or reduction in rights of any Entity under any Contract providing
for the license of any Entity Intellectual Property Assets to such Entity,
except for any such terminations, cancellations or reductions that, individually
or in the aggregate, would not have a Material Adverse Effect. No Entity is
infringing or otherwise violating in any material respect the Intellectual
Property Assets of any other Person.


                                       10

<PAGE>

          2.10 CONTRACTS.

               (a) As of the date hereof, Schedule 2.10(a) contains a true and
complete listing of the following Contracts to which any Entity is a party
(collectively, the "Material Contracts"):

                    (i) except for any intercompany Indebtedness that will be
cancelled prior to Closing, each Contract for Indebtedness or the borrowing of
money, or securing Indebtedness or the borrowing of money, by any Entity
involving an obligation in excess of $500,000;

                    (ii) each natural gas transportation, storage, gathering or
processing Contract that individually involves revenues of the Entities in
excess of $500,000 for the year to date period ended on the Balance Sheet Date;

                    (iii) each executory Contract for the purchase of any fixed
asset or service for a price in excess of $500,000, whether or not such purchase
is in the ordinary course of business;

                    (iv) each Contract involving a remaining commitment by the
Entities to pay capital expenditures in excess of $500,000;

                    (v) each Contract for lease of personal property or real
property involving aggregate payments in excess of $500,000 in any calendar
year;

                    (vi) each employment Contract and each Contract providing
retention, severance or project bonus payments, in each case that have not been
paid in full as of the date of this Agreement;

                    (vii) each Contract with any union, trade organization or
bargaining unit representative;

                    (viii) each material acquisition, divestiture or merger
agreement;

                    (ix) each joint venture or partnership agreement;

                    (x) except for Contracts otherwise described in this Section
2.10, each Contract between ONEOK or any of its Affiliates (other than the
Entities) or any officer, director or manager of any Entity, on the one hand,
and any Entity on the other hand, involving payments by or to Entities in excess
of $500,000 in any calendar year;

                    (xi) each Contract that provides for a limit on the ability
of an Entity or its Affiliates to compete in any line of business or with any
Person or in any geographic area during any period of time after the Closing;

                    (xii) each Shared Contract involving payments by or to
Entities in excess of $500,000 in any calendar year;


                                       11

<PAGE>

                    (xiii) each Drop-Down Contract involving payments by or to
Entities in excess of $500,000 in any calendar year; and

                    (xiv) each Contract not otherwise listed above involving
aggregate payments (contingent or otherwise), by or to the Entities in excess of
$500,000 in any future calendar year that cannot be terminated by the Entities
upon 60 days or less notice without penalty.

               (b) True and complete copies of all Material Contracts have been
made available to Northern Border.

               (c) Except as would not, individually or in the aggregate, have a
Material Adverse Effect, (i) each Material Contract is in full force and effect
and represents the legal, valid and binding obligation of the Entity that is a
party thereto and, to the Knowledge of ONEOK, represents the legal, valid and
binding obligation of the other parties thereto, and (ii) the Entities are not
and, to the Knowledge of ONEOK, no other party is in material breach of any
Material Contract, and neither ONEOK nor any Entity has received any written or,
to the Knowledge of ONEOK, oral notice of termination or breach of any Material
Contract. For purposes of this Section 2.10(c) only, "Material Contracts" shall
also include all Contracts of the types described in Section 2.10(a) above
entered into by any Entity between the date hereof through and including the
Closing Date.

          2.11 COMPLIANCE. Each Entity is, and at all times since January 1,
2001 has been, in material compliance with all applicable Legal Requirements,
except for such instances of non-compliance that, individually or in the
aggregate would not have a Material Adverse Effect. Since January 1, 2001, none
of ONEOK or any Entity has received any written notice from any Governmental
Authority regarding any actual or possible material violation of or material
failure by any Entity to comply with any Legal Requirement that has resulted, or
would reasonably be expected to result, in any material fine, penalty or
Liability. Each Entity holds all Permits necessary for it to own and operate its
assets and for the conduct of the Business as now being conducted, other than
any Permits, the failure of which to hold would not, individually or in the
aggregate, have a Material Adverse Effect and there is no suspension or
cancellation of any such Permits pending or, to the Knowledge of ONEOK,
threatened.

          2.12 LITIGATION. Except as disclosed in Schedule 2.12, there are no
Legal Proceedings pending or, to the Knowledge of ONEOK, threatened (a) that (i)
seeks more than $1,000,000 in damages for which any Entity could be liable, (ii)
seeks injunctive relief against any Entity, its assets or its activities or
(iii) is, or seeks to be certified as, a class or similar representative action
and involves any Entity or the material assets of any Entity, or (b) that
challenges or otherwise seeks to prevent, enjoin, alter or delay the
consummation of the transactions contemplated hereby. No Entity (nor any of the
material assets of any Entity) is subject to any outstanding Governmental Order.

          2.13 INSURANCE. Schedule 2.13 identifies all insurance policies
maintained by, at the expense of or for the benefit of any Entity and identifies
any material unresolved claims made thereunder. ONEOK has previously made
available to Northern Border accurate and complete copies of the insurance
policies identified on Schedule 2.13. Each of such insurance


                                       12

<PAGE>

policies is in full force and effect, and the Entities have paid all premiums
due thereunder. Since January 1, 2005, no Entity has received any written notice
or other communication regarding any actual or possible (a) cancellation or
invalidation of any insurance policy, (b) refusal of any coverage or rejection
of any material claim under any insurance policy, or (c) material adjustment in
the amount of the premiums payable with respect to any insurance policy.

          2.14 RELATED TRANSACTIONS. Except as set forth on Schedule 2.14, and
other than through ownership of the Shares, no Related Party (a) has any direct
or indirect ownership interest in any material asset used in or otherwise
relating to the Business; (b) is indebted to any Entity in an amount exceeding
$500,000; (c) has any direct or indirect financial interest in any Material
Contract; and (d) has any claim against any Entity in excess of $500,000 (other
than rights to receive compensation for services performed as an employee of the
Entity or its Subsidiaries). Each of the following shall be deemed to be a
"Related Party": (i) ONEOK and its Affiliates (other than the Entities); (ii)
each individual who is an officer or director of ONEOK, its Affiliates or any
Entity; (iii) each member of the immediate family of each of the individuals
referred to in clause "(ii)" above; and (iv) any trust or other entity (other
than ONEOK or any Entity, Northern Border and any Subsidiary of Northern Border)
in which any one of the individuals referred to in clauses "(ii)" and "(iii)"
above holds (or in which more than one of such individuals collectively hold),
beneficially or otherwise, a controlling voting, proprietary or equity interest.

          2.15 EMPLOYEE BENEFIT MATTERS. Except as set forth on Schedule 2.15:

               (a) All of the employees engaged in running and operating the
Business are employees of ONEOK or its Affiliates (other than the Entities).
None of the Entities have any employees or any Liabilities under any current or
former Employee Benefit Plan.

               (b) No Entity has any Liabilities in respect of Employee Benefit
Plans or employment matters relating to current or former employees of such
Entity or any current or former ERISA Affiliate of such Entity.

               (c) Neither ONEOK or any of its Affiliates (including the
Entities) is a party to, or bound by, any collective bargaining agreement,
Contract or other understanding with a labor union with respect to any employees
who perform services in connection with the businesses of the Entities, and, to
the Knowledge of ONEOK, there are not any union organizing efforts underway with
respect to any such employees. There are no unfair labor practice or labor
arbitration proceedings pending or, to the Knowledge of ONEOK, threatened
against any Entity.

               (d) Each Entity is in compliance, in all material respects, with
all applicable Legal Requirements respecting employment, employment practices,
labor, terms and conditions of employment and wages and hours, and no Entity has
or would reasonably be expected to have any Liability arising out of any failure
of ONEOK or its Affiliates (other than the Entities) to comply with any such
Legal Requirements.

               (e) None of the Entities is obligated to make any payments, or is
party to any agreement that could obligate it to make any payments, that would
not be deductible under Code


                                       13

<PAGE>

section 162(m) or 280G of the Code, or would be considered a payment under a
nonqualified deferred compensation plan, as contemplated in Code section 409A.

          2.16 ENVIRONMENTAL MATTERS. Notwithstanding any other provision in
this Agreement, this Section 2.16 contains the exclusive representations of
ONEOK concerning Environmental Matters. Except as set forth on Schedule 2.16:

               (a) Each Entity is, and at all times since January 1, 2001 has
been, in material compliance with all applicable Environmental Laws;

               (b) There have been no releases of Hazardous Materials from, at,
on or under any property now owned or leased (or formerly owned or leased) by
any Entity which are required by applicable Environmental Laws to be remediated
(or would, upon discovery, be required to be remediated) by any Entity, except
for any releases that have been fully remediated or that would not, individually
or in the aggregate, have a Material Adverse Effect;

               (c) Neither ONEOK nor any Entity has received any written request
for information or written notification that it is a potentially responsible
party under CERCLA or any similar state Legal Requirement with respect to any
on-site or off-site location for which liability is currently being asserted
against them with respect to the activities or operations of the Entities and no
Entity has sent or contributed waste to any facility that is subject to a
potential claim under CERCLA or any similar state Legal Requirement;

               (d) There are no material writs, injunctions, decrees, notices of
violation, Governmental Orders or judgments outstanding, or any Legal
Proceedings pending or, to ONEOK's Knowledge, threatened, involving any Entity
relating to (i) its compliance with any Environmental Law or (ii) the release,
discharge, spill, treatment, storage or disposal of Hazardous Materials into the
environment at any location that could reasonably be expected to result in any
Entity incurring any material Liability under Environmental Law;

               (e) Each Entity has obtained, currently maintains and is in
material compliance with all Environmental Permits, and all such Environmental
Permits are in effect and no Legal Proceeding is pending with respect to any
such Environmental Permit;

               (f) Except as otherwise disclosed in the Balance Sheet, no
material expenditures, capital improvements or changes in operation are, or, to
the Knowledge of ONEOK, will be, necessary to achieve or maintain compliance
with any Environmental Permit or Environmental Law, or will be necessary as a
condition or result of the renewal, amendment or necessary modification of any
Environmental Permit; and

               (g) ONEOK has provided or made available to Northern Border all
information relevant to the environmental compliance and condition of the
Entities and all of their respective Business Facilities, and the estimated or
reasonably anticipated remediation costs related thereto.

          2.17 SECURITIES ACT. ONEOK is acquiring the Units solely for the
purpose of investment and not with a view to, or for offer or sale in connection
with, any distribution thereof in violation of the Securities Act or state
securities laws. ONEOK acknowledges that the Units


                                       14

<PAGE>

are not registered under the Securities Act or any applicable state securities
law, and that such Units may not be transferred or sold except pursuant to the
registration provisions of the Securities Act or pursuant to an applicable
exemption therefrom and pursuant to state securities laws and regulations as
applicable. ONEOK acknowledges that each certificate representing the Units
shall bear a legend in substantially the following form:

     THE UNITS REPRESENTED BY THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER
     THE SECURITIES ACT OF 1933, AS AMENDED, OR ANY STATE SECURITIES LAWS
     ("ACTS"). THE UNITS HAVE BEEN ACQUIRED FOR INVESTMENT AND MAY NOT BE SOLD
     OR OFFERED FOR SALE IN THE ABSENCE OF AN EFFECTIVE REGISTRATION STATEMENT
     FOR THE UNITS UNDER THE ACTS OR AN OPINION OF COUNSEL SATISFACTORY TO THE
     PARTNERSHIP THAT SUCH REGISTRATION IS NOT REQUIRED.

          2.18 REGULATORY MATTERS. No Entity is a "public utility company,"
"holding company" or "subsidiary" or "affiliate" of a holding company as such
terms are defined in the Public Utility Holding Company Act of 1935 (the "1935
Act"). Each Entity that is a "Natural Gas Company" as that term is defined in
Section 2 of the Natural Gas Act ("NGA") is in compliance, in all material
respects, with all provisions of the NGA and all rules and regulations
promulgated by FERC pursuant thereto. Each such Natural Gas Company is in
compliance, in all material respects, with all orders issued by FERC that
pertain to material terms and conditions and material rates charged for
services. No approval of (a) the SEC under the 1935 Act or (b) FERC under the
NGA or the Federal Power Act is required in connection with the execution of
this Agreement by ONEOK or the transactions contemplated hereby with respect to
ONEOK or the Entities. The Form No. 2 Annual Reports filed by each Natural Gas
Company with FERC for the years ended December 31, 2004 and December 31, 2003
were true, correct and complete, in all material respects, as of the dates
thereof and since December 31, 2004 no Natural Gas Company has become subject to
any proceeding under Section 5 of the NGA or any general rate case proceeding
commenced under Section 4 of the NGA by reason of a filing made with the FERC
after December 31, 2004. Except as set forth on Schedule 2.18, no approvals of
state Governmental Authorities are required in connection with the execution of
this Agreement by ONEOK or the transactions contemplated hereby with respect to
ONEOK or the Entities.

          2.19 OPERATING ASSETS.

               (a) Except as identified to the contrary in Schedule 2.19(a), (i)
except for the Drop-Down Contracts and the Shared Contracts and except as would
not reasonably be expected to have a Material Adverse Effect, the Entities own
or have the right to use the pipelines, storage facilities, gas processing
facilities, fractionators, plants, equipment and related facilities and assets
("Operating Assets") necessary to enable them to conduct their business in the
manner currently being conducted and the Entities own or have the right to use
the Operating Assets that are reflected as being owned or leased by such
Entities on the Financial Statements; (ii) the Operating Assets are free and
clear of Liens other than Permitted Liens; (iii) each Entity has good and
indefeasible title to the real property it owns in fee, free and clear of all
Liens other than Permitted Liens; and (iv) each Entity has title to its
rights-of-way and easements (A) free and clear of all Liens and claims of those
claiming by, through or under ONEOK or its Affiliates


                                       15

<PAGE>

(other than the Entities), other than Permitted Liens; and (B) sufficient to
allow such Entity to conduct its business in substantially the same manner as
such business is currently being conducted.

               (b) Except as identified to the contrary in Schedule 2.19(b), the
Operating Assets are in good operating condition and repair, ordinary wear and
tear excepted, are free of material defects and are suitable for the use for
which such assets are currently used.

          2.20 BROKERS' FEES. Except for UBS Investment Bank (the fees of which
shall be paid solely by ONEOK), no broker, finder, investment banker or other
Person is entitled to any brokerage fee, finders' fee or other commission in
connection with the transactions contemplated by this Agreement based upon
arrangements made by ONEOK or any of its Affiliates.

          2.21 BOOKS AND RECORDS. The respective books of account, minute books,
stock or other equity record books and other records of each Entity, all of
which have been made available to Northern Border, are complete and correct.

          2.22 INDEBTEDNESS. No Entity has any Indebtedness to any Person other
than Indebtedness owed to the other Entities or to ONEOK or its other
Affiliates.

          2.23 DISCLAIMER.

               (a) Except as and to the extent expressly set forth in Section 2,
(i) ONEOK makes no representations or warranties, express or implied, and (ii)
ONEOK expressly disclaims all Liability and responsibility for any
representation, warranty, statement or information made or communicated (orally
or in writing) to Northern Border or any of its Subsidiaries, employees, agents,
consultants or representatives (including, without limitation, any opinion,
information, projection or advice that may have been provided to Northern Border
by any officer, director, employee, agent, consultant, representative or advisor
of ONEOK or any of its Affiliates).

               (b) WITHOUT LIMITING THE GENERALITY OF THE FOREGOING, EXCEPT AS
EXPRESSLY REPRESENTED OTHERWISE IN SECTION 2, ONEOK EXPRESSLY DISCLAIMS ANY
REPRESENTATION OR WARRANTY, EXPRESS OR IMPLIED, ORAL OR WRITTEN, AS TO (I) TITLE
TO ANY OF THE PROPERTIES OR OTHER ASSETS OF ANY OF THE ENTITIES, (II) THE
CONTENTS, CHARACTER OR NATURE OF ANY DESCRIPTIVE MEMORANDUM OR REPORT RELATING
TO THE PROPERTIES OR OTHER ASSETS OF ANY OF THE ENTITIES, (III) ANY ESTIMATES OF
THE VALUE OF THE ASSETS OR FUTURE REVENUES GENERATED BY THE PROPERTIES OR OTHER
ASSETS OF ANY OF THE ENTITIES, (IV) THE MAINTENANCE, REPAIR, CONDITION, QUALITY,
SUITABILITY, DESIGN OR MARKETABILITY OF THE PROPERTIES OR OTHER ASSETS OF ANY OF
THE ENTITIES, OR (V) ANY OTHER MATERIALS OR INFORMATION THAT MAY HAVE BEEN MADE
AVAILABLE OR COMMUNICATED TO NORTHERN BORDER OR ITS AFFILIATES, OR ITS OR THEIR
EMPLOYEES, AGENTS, CONSULTANTS, REPRESENTATIVES OR ADVISORS IN CONNECTION WITH
THE TRANSACTIONS CONTEMPLATED BY THIS AGREEMENT OR ANY DISCUSSION OR
PRESENTATION RELATING THERETO, AND FURTHER DISCLAIMS ANY REPRESENTATION OR


                                       16

<PAGE>

WARRANTY, EXPRESS OR IMPLIED, OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
PURPOSE OR CONFORMITY TO MODELS OR SAMPLES OF MATERIALS OF ANY EQUIPMENT, IT
BEING EXPRESSLY UNDERSTOOD AND AGREED BY THE PARTIES HERETO THAT, EXCEPT AS
EXPRESSLY REPRESENTED OTHERWISE IN SECTION 2, NORTHERN BORDER SHALL BE DEEMED TO
BE OBTAINING PIPELINES, STORAGE FACILITIES, PLANTS, EQUIPMENT AND RELATED
FACILITIES AND OTHER ASSETS IN ITS PRESENT STATUS, CONDITION AND STATE OF
REPAIR, "AS IS" AND "WHERE IS" WITH ALL FAULTS AND THAT NORTHERN BORDER HAS MADE
OR CAUSED TO BE MADE SUCH INSPECTIONS AS IT DEEMS APPROPRIATE.

SECTION 3. REPRESENTATIONS AND WARRANTIES OF THE NBP PARTNERSHIPS

     Except as set forth in the disclosure schedules (the "NBP Partnerships
Disclosure Schedules") delivered by the NBP Partnerships to ONEOK on the date
hereof (it being agreed that any matter disclosed in a particular Schedule of
the NBP Partnerships Disclosure Schedules shall be deemed to have been disclosed
with respect to any other Sections of this Agreement to the extent that the
relevance of such matter to such other Section is readily apparent from the
information disclosed), the NBP Partnerships represent and warrant to ONEOK that
the statements contained in this Section 3 are true, correct and complete as of
the date of this Agreement and will be true, correct and complete as of the
Closing, except in each case to the extent that such statements are expressly
made only as of a specified date, in which case the NBP Partnerships represent
and warrant that such statements are true, correct and complete as of such
specified date.

          3.1 ORGANIZATION AND AUTHORITY OF THE NBP PARTNERSHIPS.

               (a) The NBP Partnerships are limited partnerships duly organized,
validly existing and in good standing under the laws of Delaware.

               (b) The NBP Partnerships have all requisite right, authority and
power to enter into this Agreement and each Related Agreement to be executed and
delivered by Northern Border and to carry out the transactions contemplated
hereby.

               (c) The Partnership Policy Committee and the Audit Committee of
Northern Border have each approved the execution, delivery and performance of
this Agreement and each of the other Northern Border Transaction Agreements, and
the Audit Committee has determined that the Northern Border Transaction is fair
and reasonable to Northern Border. Except as contemplated by this Agreement, the
execution, delivery and performance by the NBP Partnerships of this Agreement
and each of the other Northern Border Transaction Agreements have been duly
authorized by all necessary action of the NBP Partnerships and no other action
on the part of the NBP Partnerships is required in connection therewith.

               (d) This Agreement and each Related Agreement (including, without
limitation, the Amendment) executed and delivered by the NBP Partnerships
constitutes, or when executed and delivered will constitute, valid and binding
obligations of the NBP Partnerships


                                       17

<PAGE>

enforceable in accordance with their respective terms, except as such
enforceability may be limited by bankruptcy, insolvency or other similar laws
from time to time in effect which affect the enforcement of creditors' rights
generally.

               (e) The execution, delivery and performance by the NBP
Partnerships of this Agreement and each Related Agreement (including, without
limitation, the Amendment) executed and delivered by the NBP Partnerships, with
or without the giving of notice or the passage of time, or both, and the
issuance of the Units or the Conversion Units, as applicable:

                    (i) do not and will not conflict with or violate any
provision of the organizational documents of the NBP Partnerships;

                    (ii) do not and will not conflict with or violate any Legal
Requirements applicable to the NBP Partnerships or, except as set forth in
Schedule 3.1(e)(ii) and any filings required to be made under the HSR Act,
require the NBP Partnerships to obtain any approval, consent or waiver of, or
make any filing with, any Governmental Authority that has not been obtained or
made, except for such violations or failures to obtain such approval, consent or
waiver would not, individually or in the aggregate, have a material adverse
effect on the ability of the NBP Partnerships to perform its obligations
hereunder and consummate the transactions contemplated hereby on the Closing
Date;

                    (iii) except as set forth on Schedule 3.1(e)(iii), do not
and will not require the consent, approval or waiver of any Person (other than
any Governmental Authority), except for the approval of the issuance of the
Conversion Units by the holders of the Common Units and except for any such
consents, approvals or waivers as have been obtained or the failure of which to
be obtained would not, individually or in the aggregate, have a material adverse
effect on the ability of the NBP Partnerships to perform their obligations
hereunder and consummate the transactions contemplated hereby on the Closing
Date;

                    (iv) does not and will not breach any contract material to
the business or operations of the NBP Partnerships or result in or permit the
termination of any such contract; and

                    (v) except for issuance of the Conversion Units, do not
require the consent or approval of the holders of Common Units.

               (f) The Northern Border Partnership Agreement and the NBILP
Partnership Agreement are in full force and effect and are binding on all the
partners thereto. After the Closing, the Amendment will be effective to amend
the Northern Border Partnership Agreement in accordance with the provisions and
terms of the Amendment.

          3.2 CAPITALIZATION.

               (a) As of the date hereof, Northern Border has 46,397,214 Common
Units issued and outstanding and the partnership interests in Northern Border
are as described in the Northern Border Partnership Agreement. Except as set
forth on Schedule 3.2(a), there are no options, warrants, convertible securities
or other rights, agreements, arrangements or commitments of any character
relating to the partnership interests of Northern Border or obliging


                                       18

<PAGE>

Northern Border to issue or sell any partnership interests of Northern Border.
NBILP has a 1.0101% general partner interest issued and outstanding. All of the
limited partner interests in NBILP are held by Northern Border. Except as set
forth on Schedule 3.2(a), there are no options, warrants, convertible securities
or other rights, agreements, arrangements or commitments of any character
relating to the partnership interests in NBILP or obligating NBILP to issue or
sell any partnership interests of NBILP.

               (b) All of the Units and Conversion Units issuable to ONEOK
pursuant to this Agreement, when issued, will at time of such issuance or
conversion, as applicable, be duly authorized, validly issued, fully paid, and
nonassessable and free of preemptive rights, with no personal liability
attaching to ownership thereof, except as such non-assessability and absence of
personal liability may be affected by section 18-607 of the Delaware Revised
Limited Partnership Act. At the Closing, Northern Border will deliver to ONEOK
good and valid title to the Units, and, upon conversion, to the Conversion
Units, in each case, free and clear of any Liens, other than those imposed by
section 18-607 of the Delaware Revised Limited Partnership Act, applicable
securities laws or the Northern Border Partnership Agreement.

          3.3 LITIGATION. Except as disclosed in Schedule 3.3, there are no
Legal Proceedings pending or, to the Knowledge of the NBP Partnerships,
threatened (a) that (i) seeks more than $1,000,000 in damages for which the NBP
Partnerships or any of their Subsidiaries could be liable, (ii) seeks injunctive
relief against the NBP Partnerships or any of their Subsidiaries or any of their
respective assets or activities or (iii) is, or seeks to be certified as, a
class or similar representative action involving the NBP Partnerships or any of
their Subsidiaries or any of their respective assets, or (b) that challenges or
otherwise seeks to prevent, enjoin, alter or delay the consummation of the
transactions contemplated hereby. Neither of the NBP Partnerships nor any of
their Subsidiaries (nor any of their material assets) is subject to any
outstanding Governmental Order.

          3.4 COMPLIANCE. Except as set forth on Schedule 3.4, the NBP
Partnerships and their Subsidiaries are, and at all times since January 1, 2001
have been, in material compliance with all applicable Legal Requirements, except
for such instances of non-compliance that, individually or in the aggregate
would not have a Northern Border Material Adverse Effect. Except as set forth on
Schedule 3.4, since January 1, 2001, neither of the NBP Partnerships nor any of
their Subsidiaries have received any written notice from any Governmental
Authority regarding any actual or possible material violation of or material
failure to comply with any Legal Requirement that has resulted, or would
reasonably be expected to result, in any material fine, penalty or Liability.
Except as set forth on Schedule 3.4, the NBP Partnerships and their Subsidiaries
hold all Permits necessary for the conduct of their business as now being
conducted, other than any Permits the failure of which to hold would not,
individually or in the aggregate, have a Northern Border Material Adverse
Effect, and there is no suspension or cancellation of any such Permits pending
or, to the Knowledge of the NBP Partnerships, threatened.

          3.5 EMPLOYEE MATTERS. Except for the Black Mesa Companies:

               (a) Neither of the NBP Partnerships nor any of their Subsidiaries
has at any time maintained, sponsored or been obligated to contribute to any
Employee Benefit Plan.


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               (b) There are no liabilities owed by the NBP Partnerships or any
of their Subsidiaries in respect of current or former employees or employment
related matters, other than to employees or former employees of ONEOK or its
Affiliates who provide services primarily to one or more of the Entities.

               (c) Neither of the NBP Partnerships nor any of their Subsidiaries
is a party to, or bound by, any collective bargaining agreement, Contract or
other understanding with a labor union. There are no unfair labor practice or
labor arbitration proceedings pending or, to the Knowledge of the NBP
Partnerships, threatened in writing against the NBP Partnerships or any of their
Subsidiaries.

          3.6 ENVIRONMENTAL MATTERS. Notwithstanding any other provision in this
Agreement, this Section 3.6 contains the exclusive representations of the NBP
Partnerships concerning Environmental Matters. Except as set forth on Schedule
3.6:

               (a) The NBP Partnerships and their Subsidiaries are, and at all
times since January 1, 2005 have been, in material compliance, with all
applicable Environmental Laws;

               (b) There have been no releases of Hazardous Materials at, on or
under any property now owned or leased (or formerly owned or leased) by the NBP
Partnerships or any of their Subsidiaries which are required by applicable
Environmental Laws to be remediated by the NBP Partnerships or any of their
Subsidiaries, except for any releases that have been fully remediated or that
would not, individually or in the aggregate, have a Northern Border Material
Adverse Effect;

               (c) Neither of the NBP Partnerships nor any of their Subsidiaries
has received any written request for information or written notification that it
is a potentially responsible party under CERCLA or any similar state Legal
Requirement with respect to any on-site or off-site location for which liability
is currently being asserted against them with respect to the activities or
operations of the NBP Partnerships and their Subsidiaries and neither of the NBP
Partnerships nor any of their Subsidiaries has sent or contributed waste to any
facility that is subject to a potential claim under CERCLA or any similar state
Legal Requirement;

               (d) There are no material writs, injunctions, decrees, notices of
violation, Governmental Orders or judgments outstanding, or any Legal
Proceedings pending or, to the Knowledge of the NBP Partnerships, threatened,
involving the NBP Partnerships or any of their Subsidiaries relating to (i) its
compliance with any Environmental Law or (ii) the release, discharge, spill,
treatment, storage or disposal of Hazardous Materials into the environment at
any location that could reasonably be expected to result in the NBP Partnerships
or any of their Subsidiaries incurring any material Liability under
Environmental Law;

               (e) The NBP Partnerships and each of their Subsidiaries has
obtained, currently maintains and is in material compliance with all
Environmental Permits, and all such Environmental Permits are in effect and no
Legal Proceeding is pending with respect to any such Environmental Permit; and

               (f) Except to the extent set forth in or reserved against in the
consolidated financial statements of Northern Border contained in the Northern
Border SEC Documents, no


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material expenditures, capital improvements or changes in operation are, or, to
the Knowledge of the NBP Partnerships, will be, necessary to achieve or maintain
compliance with any Environmental Permit or Environmental Law, or will be
necessary as a condition or result of the renewal, amendment or necessary
modification of any Environmental Permit.

          3.7 ABSENCE OF CERTAIN CHANGES. As of the date hereof, since September
30, 2005 (a) there has not been any Northern Border Material Adverse Effect and
(b) the business of Northern Border and its consolidated Subsidiaries has been
conducted in all material respects only in the ordinary course consistent with
past practice.

          3.8 SECURITIES ACT. The NBP Partnerships are acquiring the Shares
solely for the purpose of investment and not with a view to, or for offer or
sale in connection with, any distribution thereof in violation of the Securities
Act or state securities laws. The NBP Partnerships acknowledge that the Shares
are not registered under the Securities Act or any applicable state securities
law, and that such Shares may not be transferred or sold except pursuant to the
registration provisions of the Securities Act or pursuant to an applicable
exemption therefrom and pursuant to state securities laws and regulations as
applicable.

          3.9 SEC FILINGS.

               (a) The NBP Partnerships have made available to ONEOK true and
complete copies of all SEC Documents filed by Northern Border with the SEC since
January 1, 2004 (the "Northern Border SEC Documents"), which are all of the
documents (other than preliminary material) that Northern Border was required to
file with the SEC since such date. As of their respective dates, the Northern
Border SEC Documents complied in all material respects with the applicable
requirements of the Securities Act or the Exchange Act, as the case may be, and
the rules and regulations promulgated thereunder. None of the Northern Border
SEC Documents, including, without limitation, any exhibits, financial statements
or schedules included therein, at the time filed contained any untrue statement
of material fact or omitted to state a material fact required to be stated
therein or necessary to make the statements therein, in light of the
circumstances under which they were made, not misleading. The financial
statements (including the related notes and schedules) of Northern Border
included in the Northern Border SEC Documents comply as to form in all material
respects with the published rules and regulations of the SEC with respect
thereto, were prepared in accordance with GAAP applied on a consistent basis
during the periods involved (except as may be indicated in the notes thereto or,
in the case of the unaudited statements, as permitted by the rules of the SEC)
and fairly present in accordance with the applicable requirements of GAAP
(subject, in the case of the unaudited statements, to normal, recurring
adjustments, none of which will be material), the consolidated financial
position of Northern Borde