1
                                                                EXHIBIT 10.13

                                MERGER AGREEMENT

                                      AMONG

                           SOUTHWEST GAS CORPORATION,

                      SOUTHWEST GAS CORPORATION OF ARIZONA

                                       AND

                       NORTHERN PIPELINE CONSTRUCTION CO.

                              NOEL T. COON, ET UX.

                           WILLIAM L. JOHNSON, ET UX.

                            MICHAEL J. KEMPER, ET UX.

                                   DATED AS OF

                                November 13, 1995


   2
                                TABLE OF CONTENTS



                                                                                            Page
                                                                                            ----
                                                                                     
                                                                                          
         Recitals..........................................................................    1
                                                                                     
 1.      Plan of Merger....................................................................    1
         1.1      The Merger...............................................................    1
         1.2      Effect of the Merger.....................................................    2
         1.3      Consummation of the Merger...............................................    2
         1.4      Articles of Incorporation and Bylaws; Directors and Officers.............    2
         1.5      Conversion of Securities.................................................    3
         1.6      Closing of NPL Transfer Books............................................    4
         1.7      Exchange of Certificates.................................................    4
         1.8      Taking of Necessary Action; Further Action...............................    5
         1.9      Fair Market Value........................................................    5
                                                                                     
 2.      Effective Time; Closing...........................................................    7
                                                                                     
 3.      Representations and Warranties of NPL.............................................    7
         3.1      Organization, Power, Good Standing, Etc..................................    7
         3.2      Capitalization...........................................................    9
         3.3      Authority................................................................   10
         3.4      No Violation.............................................................   11
         3.5      Consents and Approvals...................................................   11
         3.6      Financial Statements.....................................................   12
         3.7      Brokerage................................................................   13
         3.8      Absence of Certain Changes or Events.....................................   13
         3.9      Litigation, Etc..........................................................   14
         3.10     Taxes and Tax Returns....................................................   14
         3.11     Employees; Employee Benefit Plans........................................   15
         3.12     Compliance With Applicable Law...........................................   21
         3.13     Contracts and Agreements.................................................   21
         3.14     Disclosure...............................................................   21
         3.15     Title to Property........................................................   22
         3.16     Insurance................................................................   23
         3.17     Powers of Attorney.......................................................   24
                                                                                     
 4.      Representations and Warranties of Southwest.......................................   24
         4.1      Corporate Organization...................................................   24
         4.2      Authority................................................................   24
         4.3      No Violation.............................................................   25


                                        i


   3




                                                                                                             
         4.4      Consents and Approvals....................................................................     26
         4.5      Sufficient Resources......................................................................     26
         4.6      Litigation................................................................................     27
         4.7      Capitalization............................................................................     28
         4.8      SEC Filings...............................................................................     28
         4.9      Business Changes..........................................................................     29
         4.10     Financial Statements......................................................................     29
         4.11     Disclosure................................................................................     30

 5.      Covenants of the Parties...........................................................................     31
         5.1      Current Information.......................................................................     31
         5.2      NPL Reports...............................................................................     32
         5.3      Regulatory Matters........................................................................     32
         5.4      Further Assurances........................................................................     33
         5.5      Public Announcements......................................................................     33
         5.6      Failure to Fulfill Conditions.............................................................     34
         5.7      Tax Matters...............................................................................     34

 6.      Covenants of NPL...................................................................................     36
         6.1      Conduct of the Business of NPL............................................................     36
         6.2      No Solicitation...........................................................................     40
         6.3      Access to Management, Properties and Records; Confidentiality.............................     40
         6.4      Assignment of Contract Rights.............................................................     42

 7.      Employees; Employee Benefit Plans..................................................................     42
         7.1      Covenants of NPL..........................................................................     42

 8.      Closing Conditions.................................................................................     43
         8.1      Conditions to Each Party's Obligations Under This Agreement...............................     43
         8.2      Conditions to the Obligations of Southwest Under This Agreement...........................     43
         8.3      Conditions to the Obligations of NPL Under This Agreement.................................     45

 9.      Closing............................................................................................     46
         9.1      Date and Place............................................................................     46
         9.2      NPL's Closing Documents...................................................................     47
         9.3      Southwest's Closing Documents.............................................................     47

10.      Post-Closing Obligations...........................................................................     47
         10.1     Registration of Southwest Common Stock....................................................     47
         10.2     Restrictions on Sale of Acquired Stock....................................................     54

11.      Termination, Amendment and Waiver..................................................................     56
         11.1     Termination...............................................................................     56


                                       ii


   4




                                                                                                             
         11.2     Amendment, Extension and Waiver...........................................................     58

12.      Expenses...........................................................................................     58

13.      Indemnification....................................................................................     59
         13.1     Indemnification of Southwest..............................................................     59
         13.2     Southwest Indemnification.................................................................     60
         13.3     Claims for Indemnity......................................................................     61

14.      Miscellaneous......................................................................................     63
         14.1     Non-Compete Agreements....................................................................     63
         14.2     NPL Promissory Notes to Noel T. Coon......................................................     64
         14.3     Survival..................................................................................     64
         14.4     Notices...................................................................................     64
         14.5     Parties in Interest.......................................................................     65
         14.6     Entire Agreement..........................................................................     66
         14.7     Counterparts..............................................................................     66
         14.8     Governing Law.............................................................................     66
         14.9     Headings..................................................................................     66
         14.10    Enforcement Costs.........................................................................     66



                                       iii


   5
                                MERGER AGREEMENT

         This Merger Agreement (the "Agreement") is made and entered into as of
the 13th day of November, 1995 by and among Southwest Gas Corporation, a
California corporation ("Southwest"), Southwest Gas Corporation of Arizona, a
Nevada Corporation wholly owned by Southwest (the "Merger Sub"), and Northern
Pipeline Construction Co., a Minnesota corporation ("NPL"), and Noel T. Coon and
Alexa S. Higashi, his wife, William L. Johnson and Judy Johnson, his wife, and
Michael J. Kemper and Frances Kemper, his wife ("NPL Shareholders").

                                    RECITALS

         The respective boards of directors of Southwest and NPL have determined
that it is advisable to consummate the Merger described in Section 1 (the
"Merger"), as a result of which all of the outstanding NPL common stock will be
converted into shares of the Common Stock, $1.00 par value per share, of
Southwest ("Southwest Common Stock") and NPL will be owned directly or
indirectly by Southwest; all on the terms and subject to the conditions set
forth in this Agreement.

         NOW, THEREFORE, the parties agree as follows:

         1. Plan of Merger. The respective boards of directors of Southwest,
Merger Sub and NPL have approved or will approve, by resolutions duly adopted,
the following provisions of this Section 1 as the Plan of Merger required by the
laws of the states of Minnesota and Nevada in connection with the Merger:

                  1.1 The Merger. At the Effective Time (as defined in Section
1.3), in accordance with this Agreement and applicable law, NPL shall be merged
with and into


   6



the Merger Sub, the separate existence of NPL (except as may be continued by
operation of law) shall cease, and the Merger Sub shall continue as the
surviving corporation under the corporate name possessed by NPL immediately
prior to the Effective Time, subject to Section 1.4 of this Agreement. The
Merger Sub, in its capacity as the corporation surviving the Merger, sometimes
is referred to herein as the "Surviving Corporation."

                  1.2 Effect of the Merger. The Surviving Corporation shall
possess all the rights, privileges, immunities and franchises, of a public as
well as of a private nature, of each of the Merger Sub and NPL (collectively,
the "Constituent Corporations"); and all property, real, personal, and mixed,
and all debts due on whatever account, including subscriptions to shares, and
all other choses in action, and all and every other interest of or belonging to
or due to each of the Constituent Corporations, shall be taken and deemed to be
transferred to and vested in the Surviving Corporation without further act or
deed; and the Surviving Corporation shall be responsible and liable for all
liabilities and obligations of each of the Constituent Corporations.

                  1.3 Consummation of the Merger. On the Closing Date, the
parties hereto will cause articles of merger relating to the Merger to be
delivered to the Secretary of State of the states of Minnesota and Nevada, in
such form as required by, and executed in accordance with, the relevant
provisions of applicable law. The Merger shall be effective at such time as such
articles of merger are duly filed by the Secretary of State of the states of
Minnesota and Nevada in accordance with the applicable law (the "Effective
Time").

                  1.4 Articles of Incorporation and Bylaws; Directors and
Officers. The Articles of Incorporation and Bylaws of the Merger Sub, as in
effect immediately prior to 

                                        2


   7



the Effective Time, shall be the Articles of Incorporation (except that such
Articles of Incorporation shall be amended as of the Effective Time to change
the name to NPL) and Bylaws (except that such Bylaws shall be amended as of the
Effective Time to change the name to NPL) of the Surviving Corporation
immediately after the Effective Time and shall thereafter continue to be its
Articles of Incorporation and Bylaws until amended as provided therein and under
the applicable law. The directors of the Merger Sub holding office immediately
prior to the Effective Time shall be the directors of the Surviving Corporation
immediately after the Effective Time. The officers of the Merger Sub holding
office immediately prior to the Effective Time shall sign letters of resignation
on or prior to the Closing. The officers of NPL (except Noel T. Coon) holding
office immediately prior to the Effective Time shall be the officers (holding
the same offices as they held with NPL) of the Surviving Corporation immediately
after the Effective Time.

                  1.5 Conversion of Securities. At the Effective Time, by virtue
of the Merger and without any action on the part of the Merger Sub, NPL or the
holder of any of the following securities:

                  (a) All shares of NPL Common Stock issued and outstanding
         immediately prior to the Effective Time (other than shares to be
         canceled pursuant to Section 1.5[b]) shall automatically be canceled
         and extinguished and be converted into and become a right to receive
         the number of shares of Southwest Common Stock to be calculated in
         accordance with Section 1.9 having a total Fair Market Value of
         Southwest Common Stock equal to twenty-four million dollars
         ($24,000,000). Each NPL Shareholder shall be entitled to receive his
         proportionate share of such

                                        3


   8



         Southwest Common Stock based upon his percentage ownership interest of
         NPL Common Stock at the Effective Time. Cash will be issued in lieu of
         fractional shares based on Fair Market Value.

                  (b) Each share of NPL Common Stock issued and outstanding
         immediately prior to the Effective Time and held in the treasury of
         NPL or owned by Southwest or the Merger Sub shall automatically be
         canceled and extinguished and no payment shall be made with respect
         thereto.

                  (c) Each share of Merger Sub Common Stock, par value $1.00 per
         share, issued and outstanding immediately prior to the Effective Time
         shall automatically be converted into and become one validly issued,
         fully paid and nonassessable share of Common Stock, par value $1.00 per
         share, of the Surviving Corporation.

                  1.6 Closing of NPL Transfer Books. At the Effective Time, the
stock transfer books of NPL shall be closed and no transfer of shares of NPL
Common Stock issued and outstanding immediately prior to the Effective Time
shall thereafter be made. If, after the Effective Time, valid certificates
previously representing such shares are presented to the Surviving Corporation
or the Disbursing Agent (as defined in Section 1.7), they shall be exchanged as
provided in Section 1.7.

                  1.7 Exchange of Certificates. After the Effective Time, the
Stock Transfer Department of Southwest shall act as Disbursing Agent (the
"Disbursing Agent") in effecting the exchange of Southwest Common Stock for
certificates which, immediately prior to the Effective Time, represented shares
of NPL Common Stock entitled to such exchange pursuant to Section 1.5(a). Upon
the surrender and exchange of a certificate

                                        4


   9



theretofore representing shares of NPL Common Stock, the holder shall be issued
a certificate representing the number of shares of Southwest Common Stock to
which he is entitled pursuant to Section 1.5(a) and the certificate representing
NPL Common Stock shall forthwith be canceled. Until so surrendered and
exchanged, each such certificate shall represent solely the right to receive the
Southwest Common Stock into which the shares of NPL Common Stock it theretofore
represented shall have been converted pursuant to Section 1.5(a), and the
Surviving Corporation shall not be required to issue to the holder thereof the
Southwest Common Stock to which he otherwise would be entitled; provided that
procedures allowing for issuance against lost or destroyed certificates against
receipt of customary and appropriate certifications and indemnities shall be
provided.

                  1.8 Taking of Necessary Action; Further Action. Southwest and
the Merger Sub, on the one hand, and NPL and NPL Shareholders, on the other
hand, shall use all reasonable efforts to take all such action (including
without limitation action to cause the satisfaction of the conditions of the
other to effect the Merger) as may be necessary or appropriate in order to
effectuate the Merger as promptly as possible. If, at any time after the
Effective Time, any further action is necessary or desirable to carry out the
purposes of this Agreement and to vest the Surviving Corporation with full
possession of all the rights, privileges, immunities and franchises of the
Constituent Corporations, the officers and directors of the Surviving
Corporation are fully authorized in the name of the Constituent Corporations or
otherwise to take, and shall take, all such action.

                  1.9 Fair Market Value.


                                        5


   10


                  (a) For purposes of this Agreement, the "Fair Market Value" of
         a share of Southwest Common Stock shall be determined as follows:

                           (i) Upon receipt of all required regulatory approvals
                  of the Merger, the parties shall as promptly as practicable
                  make a joint public announcement (the "Public Announcement")
                  that such regulatory approvals have been obtained.

                           (ii) The "Fair Market Value" of a share of Southwest
                  Common Stock shall be the average of the closing prices of the
                  Southwest Common Stock on the New York Stock Exchange, for the
                  twenty trading days ending on the trading day which is five
                  trading days prior to the Closing Date. The closing prices
                  printed in The Wall Street Journal will be presumed to be
                  correct in the absence of evidence to the contrary.

                  (b) Notwithstanding Section 1.9(a):

                           (i) If the Fair Market Value of a share of Southwest
                  Common Stock determined as provided in Section 1.9(a) is
                  greater than $17.50, Noel T. Coon may terminate this Agreement
                  (on behalf of NPL and NPL Shareholders) by written notice to
                  Southwest delivered not less than two business days prior to
                  the Closing Date unless Southwest and Merger Sub notify Noel
                  T. Coon in writing on or prior to the Closing Date that
                  Southwest and Merger Sub agree that, for purposes of this
                  Agreement, the Fair Market Value of a share of Southwest
                  Common Stock shall be $17.50; and

                           (ii) If the Fair Market Value of a share of Southwest
                  Common 

                                        6


   11


                  Stock determined as provided in Section 1.9(a) is less than
                  $15.00, Southwest may terminate this Agreement by written
                  notice to Noel T. Coon delivered not less than two business
                  days prior to the Closing Date unless Noel T. Coon notifies
                  Southwest in writing on or prior to the Closing Date that he
                  agrees (on behalf of NPL and NPL Shareholders) that, for
                  purposes of this Agreement, the Fair Market Value of a share
                  of Southwest Common Stock shall be $15.00.

                           (iii) NPL and NPL Shareholders each agree to be bound
                  by the decision made by Noel T. Coon pursuant to the
                  provisions of subsections 1.9(b)(i) and (ii) above.

                           In the event of any termination of this Agreement
                  pursuant to Section 1.9(b), the parties hereto shall have no
                  further obligation whatsoever to each other hereunder except
                  pursuant to those provisions of this Agreement which expressly
                  survive the termination hereof.

         2. Effective Time; Closing. The Merger shall become effective at the
Effective Time.

         3. Representations and Warranties of NPL. The "NPL Disclosure
Schedules" shall mean all of the disclosure schedules required by this
Agreement, dated as of the date hereof, which have been delivered by NPL. NPL
hereby represents and warrants to Southwest as follows:

                  3.1 Organization, Power, Good Standing, Etc.

                  (a) NPL is a corporation duly organized, validly existing and
         in good


                                       7
   12



         standing under the laws of the State of Minnesota. NPL has all the
         requisite corporate power and authority to own, lease and operate all
         of its properties and assets and to carry on its business as currently
         conducted. NPL is duly licensed or qualified to do business and is in
         good standing in each jurisdiction in which the nature of the business
         conducted by it makes such licensing or qualification necessary and
         where the failure to be so qualified would, individually or in the
         aggregate, have a Material Adverse Effect (as defined below) on NPL.
         NPL has heretofore delivered to Southwest correct copies of its
         Articles of Incorporation (the "Articles") and its Bylaws as in effect
         on the date hereof. As used in this Agreement, the term "Material
         Adverse Effect" with respect to a party shall mean any change or effect
         that is reasonably likely to be materially adverse to the business,
         operations, properties, condition (financial or otherwise), assets or
         liabilities of such party taken as a whole.

                  (b) NPL has no subsidiaries. NPL has no affiliates, other than
         other businesses, firms, corporations, partnerships, joint ventures, or
         similar organizations which are owned in whole or in part by Noel T.
         Coon.

                  (c) The minute books of NPL contain materially complete and
         accurate records of all meetings held and other corporate action taken,
         since December 31, 1990, by the company's stockholders and Board of
         Directors.

                  (d) Except as set forth on Disclosure Schedule 3.1(d), NPL
         does not own (beneficially or otherwise) any capital stock or other
         equity interest in any corporation or other entity.

                                       8
   13

                  (e) Except as listed on Disclosure Schedule 3.1(e), NPL is not
         a party to nor is it or any of its assets bound by any agreement which
         relates to any equity interest of NPL in any partnership, joint
         venture, or similar enterprise pursuant to which NPL may be required to
         transfer funds in respect of any equity interest to, make an investment
         in, or guarantee or assume any debt, dividend or other obligation of,
         any person, entity, partnership, joint venture or similar enterprise,
         or pursuant to which NPL is or is required to become an equity
         investor.

                  (f) Except as specifically disclosed in this Agreement, no
         other agreements, either written or oral, exist between NPL and Noel T.
         Coon or businesses owned by Noel T. Coon which would require the
         transfer of NPL funds or assets.

                  3.2 Capitalization. The authorized capital stock of NPL
consists of 15,000 shares of common stock, par value $10 per share ("NPL Common
Stock"). As of the date hereof, 5,771 shares of NPL Common Stock (and no shares
of NPL Preferred Stock) were issued and outstanding. No shares of stock are held
in NPL's treasury. All of the issued and outstanding shares of NPL Common Stock
have been duly authorized, validly issued, and are fully paid and nonassessable,
with no personal liability attaching to the ownership thereof. Other than shares
reserved for issuance under the Stock Purchase Agreement (as hereinafter
defined), there are no shares of NPL Common Stock reserved for issuance for any
reason. NPL is not bound by any outstanding subscriptions, options, warrants,
calls, commitments or agreements of any character calling for the transfer,
purchase, or issuance of any shares of its capital stock or any securities
representing the right to

                                       9
   14

purchase or otherwise receive any shares of its capital stock or any securities
convertible into or representing the right to purchase or subscribe for any such
shares except for the obligations of NPL under the Stock Purchase Agreement of
March 7, 1994, as amended (the "Stock Purchase Agreement"), providing for the
possible issuance of up to 1,236 additional shares each to Messrs. Johnson and
Kemper (up to 2,472 in total) in order to implement said Agreement.
Notwithstanding the foregoing, NPL further represents that all of its stock is
now owned by Noel T. Coon and that William L. Johnson and Michael J. Kemper have
an option to purchase up to 15 percent each of the outstanding shares of NPL by
purchasing with promissory notes ("Option Notes") newly issued shares of NPL
from NPL as provided in the Amendment to Stock Purchase Agreement dated November
12, 1995. Immediately prior to the exercise of such option, NPL will issue a
dividend to Noel T. Coon in the form of a promissory note ("Dividend Note") in
the amount equal to (and conditioned upon the execution and delivery of) the
Option Notes. NPL will pay and discharge the Dividend Note by transferring the
Option Notes to Coon. Southwest hereby consents to the exercise of the option,
the foregoing dividend and payment of the Dividend Note as provided above, and
agrees to recognize Messrs. Johnson and Kemper as shareholders of NPL in the
event the option is legally exercised in accordance with its terms on or prior
to the Closing Date.

                  3.3 Authority. NPL and NPL Shareholders have the requisite
power and authority to execute and deliver this Agreement and to consummate the
transactions contemplated hereby. Assuming the due authorization, execution and
delivery hereof by the other parties hereto, this Agreement constitutes a valid
and binding obligation of NPL

                                       10
   15

and NPL Shareholders, enforceable against them in accordance with its terms.

                  3.4 No Violation. Except as listed on Disclosure Schedule 3.4,
neither the execution and delivery of this Agreement nor the consummation by NPL
or NPL Shareholders of the transactions contemplated hereby, nor compliance by
NPL or NPL Shareholders with any of the terms or provisions hereof, will (i)
violate any provision of the Articles or Bylaws of NPL, (ii) assuming the
consents and approvals referred to in Section 3.5 hereof are duly obtained,
violate any statute, code, ordinance, rule, regulation, judgment, order, writ,
decree or injunction applicable to NPL, or any of its respective properties or
assets, or (iii) violate, conflict with, result in a breach of any provisions
of, constitute a default (or an event which, with notice or lapse of time, or
both, would constitute a default) under, result in the termination of,
accelerate the performance required by, or result in the creation of any lien,
security interest, charge or other encumbrance upon any of the properties or
assets of NPL, under any of the terms, conditions or provisions of any note,
bond, mortgage indenture, deed of trust, license, lease, agreement or other
instrument or obligation to which NPL is a party, or by which it or any of its
properties or assets may be bound or affected, except with respect to (iii)
above, for such violations, conflicts, breaches, defaults, terminations,
accelerations and encumbrances which would not prevent consummation of the
transactions contemplated hereby and would not have a Material Adverse Effect.
Prior to Closing, NPL and NPL Shareholders shall provide written evidence to
Southwest that NPL has obtained approvals or waivers for all restrictions listed
on Disclosure Schedule 3.4.

                  3.5 Consents and Approvals. Except for (i) consents and
approvals of,

                                       11
   16

deliveries to, or filings or registrations with the Securities and Exchange
Commission (the "SEC"), the Federal Trade Commission (the "FTC"), the United
States Department of Justice (the "Justice Department"), or other applicable
federal and state governmental authorities and (ii) the consents, approvals,
filings or registrations set forth on Disclosure Schedule 3.4, no consents or
approvals of or filings or registrations with any third party or public body or
authority, except for consents, approvals, filings or registrations where the
failure to obtain such consents or approvals or to make such filings or
registrations would not prevent or delay the Merger or have a Material Adverse
Effect, are necessary in connection with the execution and delivery by NPL and
NPL Shareholders of this Agreement and the consummation of the Merger.

                  3.6 Financial Statements.

                  (a) NPL has previously delivered or made available to
         Southwest copies of (i) the balance sheets of NPL as of December 31,
         1992, 1993 and 1994 respectively, and the related statements of income
         and retained earnings and statements of cash flows for each of the
         three years ended, respectively, on December 31, 1992, 1993 and 1994,
         in each case accompanied by the NPL audit reports of Deloitte & Touche
         LLP, independent public accountants, with respect to NPL (the "NPL
         1992, 1993 and 1994 Financial Statements" respectively), and (ii) the
         unaudited balance sheet of NPL as of July 30, 1995 and the related
         unaudited income statement for the seven-month period then ended (the
         "July 1995 Financial Statements"). The NPL 1992, 1993 and 1994
         Financial Statements referred to herein (including the related notes)
         present fairly the financial position of NPL, as


                                       12
   17

         of the respective dates set forth therein, and present fairly the
         results of the operations and changes in stockholders' equity and cash
         flows of NPL for the respective fiscal periods or as of the respective
         dates set forth therein.

                  (b) The NPL 1992, 1993 and 1994 Financial Statements
         (including the related notes) have been prepared in accordance with
         generally accepted accounting principles consistently applied during
         the periods involved. The July 1995 Financial Statements present fairly
         the financial position of NPL as of the respective dates set forth
         therein, and present fairly the results of the operations of NPL for
         the seven months then ended.

                  (c) The books and records of NPL have been, and are being,
         maintained in accordance with applicable legal and accounting
         requirements.

                  3.7 Brokerage. There are no claims for investment banking
fees, brokerage commissions, finder's fees or similar compensation payable by
NPL in connection with the transactions contemplated by this Agreement.

                  3.8 Absence of Certain Changes or Events. As of the date of
this Agreement, there has not been any material adverse change in the business,
operations, properties, assets or financial condition of NPL, taken as a whole,
from that described in the audited NPL 1994 Financial Statements and, to the
best of NPL's knowledge, no fact or condition existed as of the date hereof that
NPL believes will cause such a material adverse change prior to the Closing
Date. The parties hereto agree that none of the information disclosed in the
July 1995 Financial Statements shall constitute a material adverse change for
purposes of this Agreement.

                                       13
   18

                  3.9 Litigation, Etc. As of the date of this Agreement, (a)
there are no actions, suits, claims, inquiries, proceedings or investigations
before any court, commission, bureau, regulatory, administrative or governmental
agency, arbitrator, body or authority known to NPL Shareholders or management to
be pending or threatened against NPL which will result in liabilities, including
defense costs, in excess of $1,000 in the aggregate except those listed on
Disclosure Schedule 3.9 and (b) NPL is not subject to any order, judgment or
decree and is not in default with respect to any such order, judgment or decree.

                  3.10 Taxes and Tax Returns.

                  (a) The amounts recorded as provisions for taxes in the NPL
         July 1995 Financial Statements are sufficient for all material accrued
         and unpaid federal, state, county and local taxes, interest and
         penalties of NPL, whether or not disputed, for the period ended July
         30, 1995, and for all fiscal periods prior thereto. Except as set forth
         on Disclosure Schedule 3.10(b), NPL has not been notified of an
         Internal Revenue Service examination or of an examination by any state
         tax authority. NPL has not granted any waiver of any statute of
         limitations with respect to, or any extension of a period for the
         assessment of, any Tax (as hereinafter defined). Complete and correct
         copies of the income tax returns of NPL for the four years ended
         December 31, 1994, as filed with the Internal Revenue Service and all
         state and local taxing authorities, together with all related
         correspondence and notices, have previously been made available to
         Southwest.

                  (b) Except as set forth on Disclosure Schedule 3.10(b), NPL
         has timely

                                       14
   19

         and correctly filed all federal, state, county and local tax and other
         returns and reports (collectively, "Returns") required by applicable
         law to be filed (including without limitation, estimated tax returns,
         income tax returns, excise tax returns, sales tax returns, use tax
         returns, property tax returns, franchise tax returns, information
         returns and withholding, employment and payroll tax returns), and has
         paid all taxes, levies, license and registration fees, charges or
         withholdings of any nature whatsoever shown by such Returns to be owed,
         or which are otherwise due and payable (hereinafter called "Taxes"),
         and to the extent any material liabilities for Taxes as of July 30,
         1995 have not been fully discharged, full and complete reserves have
         been established in the July 1995 Financial Statements. NPL is not in
         default in the payment of any Taxes due or payable or any assessments
         received in respect thereof except for Taxes which are being contested
         in good faith. Except as listed on Disclosure Schedule 3.10(b), no
         additional assessments of Taxes which might be payable by NPL are known
         to NPL to be proposed, pending or threatened, other than Taxes for
         periods for which returns are not yet filed and which have been
         accrued.

                  (c) There are no intercompany tax-sharing agreements to which
         NPL is a party.

                  3.11 Employees; Employee Benefit Plans.

                  (a) Except as listed on Disclosure Schedule 3.11(a), other
         than union contracts, as of the date hereof NPL is not a party to or
         bound by or in any manner liable under any contract, arrangement or
         understanding (whether written or oral)

                                       15
   20

         with respect to the employment or compensation of any officers,
         employees or consultants, and consummation of the transactions
         contemplated by this Agreement will not (either alone or upon the
         occurrence of any additional acts or events) result in payments
         (whether of severance pay or otherwise) becoming due from NPL to any
         officer or employee other than the existing employment contracts with
         Mr. William L. Johnson and Mr. Michael J. Kemper which they each hereby
         agree will automatically cancel on December 31, 1996 by mutual
         agreement without any penalty or additional compensation, except the
         bonuses earned thereunder in 1996 will be paid in 1997 when the audited
         1996 financial statements are available to determine NPL's pretax
         income. NPL agrees to accrue all costs to be incurred for severance
         payments and the Pete Middents award listed on Disclosure Statement
         3.11(a) in its 1995 Financial Statements.

                  (b) Except as listed in Disclosure Schedule 3.11(b), as of the
         date hereof, there are not, and there have not been at any time in the
         past three years, any actions, suits, claims or proceedings (which have
         been served on NPL) before any court, commission, bureau, regulatory,
         administrative or governmental agency, arbitrator, body or authority
         pending or, to the best of NPL Shareholders' or management's knowledge,
         threatened by any employees, former employees or other persons relating
         to the employment practices or activities of NPL (except for threatened
         actions which have subsequently been resolved).

                  (c) With respect to all employee benefit plans, NPL represents
         and warrants as follows:

                                       16
   21

                           (i) All employee benefit plans, as defined in Section
                  3(3) of the Employee Retirement Income Security Act of 1974,
                  as amended ("ERISA"), and any other pension, bonus, deferred
                  hospitalization, health and other employee benefit plan,
                  program or arrangement, whether formal or informal, under
                  which NPL has any obligation or liability, or under which any
                  employee or former employee of NPL has any rights to benefits
                  (the "Benefit Plans") are set forth on Disclosure Schedules
                  3.11(a) and 3.11(c)(i). All Benefit Plans that are subject to
                  the funding requirements in Title I, Subtitle B, Part 3 of
                  ERISA or Section 412 of the Internal Revenue Code of 1986, as
                  amended (the "Code"), are in compliance with such funding
                  standards, and no waiver or variance from such funding
                  requirements has been obtained or applied for under Section
                  412(d) of the Code. None of the Benefit Plans is subject to
                  Title IV of ERISA or is a "multi-employer plan," as such term
                  is defined in Section 3(37) and 4001(a)(3) of ERISA and
                  Section 414(f) of the Code.

                           (ii) Except as listed on Disclosure Schedule
                  3.11(c)(ii), the terms of the Benefit Plans are, and the
                  Benefit Plans have been administered, in accordance with the
                  requirements of ERISA, the Code, applicable law and the
                  respective plan documents. None of the Benefit Plans is under
                  audit or is the subject of an investigation by the Internal
                  Revenue Service, the U.S. Department of Labor or any other
                  federal or state governmental agency. All material reports and
                  information required to be filed with, or provided to, the

                                       17
   22

                  United States Department of Labor, Internal Revenue Service,
                  the Pension Benefit Guaranty Corporation (the "PBGC") and plan
                  participants and beneficiaries with respect to each Benefit
                  Plan have been timely filed or provided. With respect to each
                  Benefit Plan for which an annual report has been filed, no
                  material change has occurred with respect to the matters
                  covered by the most recent annual report since the date
                  thereof.

                           (iii) NPL is not aware of any facts regarding any
                  Benefit Plan which is an "employee pension benefit plan" as
                  defined in Section 3(2) of ERISA (collectively, the "Employee
                  Pension Benefit Plans") that would present a significant risk
                  that any Employee Pension Benefit Plan would not be determined
                  by the appropriate District Director of the Internal Revenue
                  Service to be "qualified" within the meaning of Section 401(a)
                  of the Code, or with respect to which any trust maintained
                  pursuant thereto is not exempt from federal income taxation
                  pursuant to Section 501 of the Code, or with respect to which
                  a favorable determination letter could not be issued by the
                  Internal Revenue Service with respect to each such Employee
                  Pension Benefit Plan.

                           (iv) With respect to each Benefit Plan, all
                  contributions, premiums or other payments due or required to
                  be made to such plans as of the Effective Time have been or
                  will be made or accrued as required by the respective plan
                  documents.

                           (v) To the best of NPL's knowledge, there are not
                  now, nor have

                                       18
   23

                  there been, any "prohibited transactions", as such term is
                  defined in Section 4975 of the Code or Section 406 of ERISA,
                  involving NPL or any officer, director or employee of NPL with
                  respect to the Benefit Plans that could subject NPL or any
                  other party in interest to the penalty or tax imposed under
                  Section 502(I) of ERISA and Section 4975 of the Code.

                           (vi) As of the date hereof, no claim, lawsuit,
                  arbitration or other action (which has been served on NPL) has
                  been instituted, asserted or, to the best of NPL Shareholders'
                  or management's knowledge, threatened by or on behalf of any
                  Benefit Plan or by any employee alleging a breach or breaches
                  of fiduciary duty or violations of other applicable state or
                  federal law with respect to such Benefit Plan, which could
                  result in liability on the part of NPL or any Benefit Plan
                  under ERISA or any other law, nor is there any basis known to
                  NPL Shareholders or management for successful prosecution of
                  such a claim, and Southwest will be notified promptly in
                  writing of any such threatened or pending claim arising
                  between the date hereof and the Closing.

                           (vii) Except as may be required by the Consolidated
                  Omnibus Budget and Reconciliation Act of 1985, as amended
                  ("COBRA"), no Benefit Plan which is an employee welfare
                  benefit plan (within the meaning of Section 3(1) of ERISA)
                  provides for continuing benefits or coverage for any
                  participant or beneficiary of a participant after such
                  participant's termination of employment nor does NPL have any
                  current or projected liability under

                                       19
   24

                  any such plans.

                           (viii) NPL has not maintained or contributed to, and
                  does not currently maintain or contribute to, any severance
                  pay plan under which any employees of NPL, other than union
                  employees, are entitled to any benefits. All payments (other
                  than regular wages and vacation pay) made to employees of NPL
                  coincident with or in connection with termination of
                  employment from January 1, 1993 to the date hereof, are
                  disclosed on Disclosure Schedule 3.11(c)(viii).

                           (ix) Except as otherwise provided in this Agreement,
                  no individual will accrue or receive any additional benefits,
                  service, or accelerated rights to payment or vesting of
                  benefits under any Benefit Plan as a result of the
                  transactions contemplated by this Agreement.

                           (x) NPL has to the extent relevant complied in all
                  material respects with all of the requirements of COBRA.

                            (xi) All amendments required to bring all Benefit
                  Plans into conformity with any of the applicable provisions of
                  ERISA and the Code have been duly adopted or will be duly
                  adopted as of the Closing Date, subject to further revisions
                  that may be required by the Internal Revenue Service.

                           (xii) No individual will accrue or receive from NPL
                  any payments, benefits, services or accelerated rights to
                  payment or vesting of benefits, or otherwise receive any other
                  rights, which would constitute a "parachute payment" as
                  defined in Section 280G(b)(2) of the Code as a result of or in

                                       20
   25

                  connection with the transactions contemplated by this
                  Agreement.

                  3.12     Compliance With Applicable Law.

                  (a) NPL holds all licenses, certificates, franchises, permits
         and other governmental authorizations ("Permits") necessary for the
         lawful conduct of its business and such Permits are in full force and
         effect, and NPL is in all respects complying therewith, except where
         the failure to possess or comply with such Permits would not have a
         Material Adverse Effect on NPL.

                  (b) Except as set forth on Disclosure Schedule 3.12(b), NPL is
         and for the past three years has been in compliance with all foreign,
         federal, state and local laws, statutes, ordinances, rules, regulations
         and orders applicable to the operation, conduct or ownership of its
         business or properties except for any noncompliance which is not
         reasonably likely to have in the aggregate a Material Adverse Effect on
         NPL.

                  3.13 Contracts and Agreements. Except as listed on Disclosure
Schedule 3.13, as of the date hereof, and except with respect to existing lease
agreements and borrowings in the ordinary course: (a) NPL is not a party to or
bound by any commitment, contract, agreement or other instrument which involves
or could involve aggregate future payments by NPL of more than $50,000; and (b)
no commitment, contract, agreement or other instrument, other than NPL's charter
documents, to which NPL is a party or by which it is bound, limits the freedom
of NPL to compete in any line of business or with any person.

                  3.14 Disclosure. To the knowledge of NPL, no representation or
warranty

                                       21
   26

regarding NPL contained in this Agreement, and no statement contained in the
Disclosure Schedules delivered by NPL hereunder, contains any untrue statement
of a material fact or omits to state a material fact necessary in order to make
a statement herein or therein, in light of the circumstances under which it was
made, not misleading.

                  3.15     Title to Property.

                  (a) Real Property. Disclosure Schedule 3.15(a) contains a
         description of all interests in real property, whether owned, leased or
         otherwise claimed, including a list of all leases of real property, in
         which NPL has or claims an interest as of the date hereof and any
         guarantees of any such leases by NPL. Each such lease is legal, valid
         and binding as between NPL and the other party or parties thereto, and
         the occupant is a tenant or possessor in good standing thereunder, free
         of any material default or breach whatsoever and quietly enjoys the
         premises provided for therein. NPL does not own any real property on
         the date hereof. All real property and fixtures material to the
         business, operations or financial condition of NPL are in good
         condition and repair, ordinary wear and tear excepted.

                  (b) Environmental Matters. Except as listed on Disclosure
         Schedule 3.15(b), the real property leased by NPL on the date hereof
         did not contain any underground storage tanks, asbestos,
         ureaformaldehyde, uncontained polychlorinated biphenyls, or, except
         for materials which are ordinarily used in office buildings and office
         equipment such as janitorial supplies and do not give rise to financial
         liability therefor under the hereafter defined Environmental Laws,
         releases of hazardous substances as such terms may be defined by all
         applicable federal, state

                                       22
   27

         or local environmental protection laws and regulations ("Environmental
         Laws"). As of the date hereof, (i) no part of any such real property
         has been listed or, to the knowledge of NPL, proposed for listing on
         the National Priorities List pursuant to the Comprehensive
         Environmental Response, Compensation and Liability Act ("CERCLA") or on
         a registry or inventory of inactive hazardous waste sites maintained by
         any state, and (ii) no notices have been received alleging that NPL was
         a potentially responsible person under CERCLA or any similar statute,
         rule or regulation. NPL knows of no material violation of law,
         regulation, ordinance (including, without limitation, laws, regulations
         and ordinances with respect to hazardous waste, zoning, environmental,
         city planning or other similar matters) relating to its respective
         properties. NPL Shareholders agree to reimburse the Surviving
         Corporation for any reasonable remediation expenses incurred or claims
         made at all the sites listed in Disclosure Schedule 3.15(b) prior to
         the first anniversary of the Closing Date in accordance with the
         deductible and maximum set forth in Section 13.1(d).

                  3.16 Insurance. Disclosure Schedule 3.16 contains a true and
complete list and a brief description (including name of insurer, agent,
coverage and expiration date) of all insurance policies in force on the date
hereof with respect to the business and assets of NPL (other than insurance
policies under which NPL is named as a loss payee or additional insured). NPL is
in compliance with all of the material provisions of all insurance policies.
Each such policy is outstanding and in full force and effect and, except as set
forth on Disclosure Schedule 3.16, NPL is the sole beneficiary of such policies
except for

                                       23
   28

additional insureds. All premiums and other payments due under any such policy
have been paid or accrued.

                  3.17 Powers of Attorney. Except as listed on Disclosure
Schedule 3.17, NPL has no powers of attorney outstanding other than those issued
pursuant to the requirements of regulatory authority.

         4. Representations and Warranties of Southwest. Southwest hereby
represents and warrants to NPL as follows:

                  4.1      Corporate Organization.

                  (a) Southwest is a corporation duly organized, validly
         existing and in good standing under the laws of the State of
         California. Southwest has all the requisite power and authority to own,
         lease and operate all of its properties and assets and to carry on its
         business as it is currently conducted, and is duly licensed or
         qualified to do business and is in good standing in each jurisdiction
         in which the nature of the business conducted by it makes such
         licensing or qualification necessary and where failure to be so
         qualified would not, individually or in the aggregate, have a Material
         Adverse Effect on Southwest.

                  (b) Merger Sub is a corporation duly organized, validly
         existing and in good standing under the laws of the State of Nevada and
         authorized to do business in the State of Arizona.

                  4.2      Authority.

                  (a) Southwest has full corporate power and authority to
         execute and deliver this Agreement and, subject to applicable
         regulatory approvals, to

                                       24
   29

         consummate the transactions contemplated hereby. The execution and
         delivery of this Agreement and consummation of the transactions
         contemplated hereby have been duly and validly approved by the Board of
         Directors of Southwest. This Agreement has been duly and validly
         executed and delivered by Southwest and, assuming the due
         authorization, execution and delivery thereof by the other parties
         hereto, constitutes valid and binding obligations of Southwest,
         enforceable against it in accordance with the terms of the Agreement.

                  (b) Southwest as the sole shareholder of Merger Sub will cause
         it to take any and all action necessary and appropriate to carry out
         its obligations under this Agreement.

                  (c) Merger Sub has full corporate power and authority to
         execute and deliver this Agreement and, subject to applicable
         regulatory approvals, to consummate the transactions contemplated
         hereby. The execution and delivery of this Agreement and consummation
         of the transactions contemplated hereby have been or will be duly and
         validly approved by the Board of Directors of Merger Sub. This
         Agreement has been duly and validly executed and delivered by Merger
         Sub and, assuming the due authorization, execution and delivery
         thereof, by the other parties hereto, constitutes valid and binding
         obligations of Merger Sub, enforceable against it in accordance with
         the terms of the Agreement.

                  4.3 No Violation. Neither the execution and delivery of this
Agreement nor the consummation by Southwest or Merger Sub of the transactions
contemplated hereby, nor compliance by Southwest or Merger Sub with any of the
terms hereof, will (i) violate

                                       25
   30

any provision of the Articles of Incorporation or Bylaws of Southwest or Merger
Sub, or (ii) assuming that the consents and approvals referred to in Section 4.4
are duly obtained, violate any statute, code, ordinance, rule, regulation,
judgment, order, writ, decree or injunction applicable to Southwest or Merger
Sub or any of their properties or assets, or (iii) violate, conflict with,
result in the breach of any provisions of, constitute a default (or an event
which, with notice or lapse of time, or both, would constitute a default) under,
result in the termination of, accelerate the performance required by, or result
in the creation of any lien, security interest, charge or other encumbrance upon
any of the respective properties or assets of Southwest or Merger Sub under, any
of the terms, conditions or provisions of any note, bond, mortgage, indenture,
deed of trust, license, lease, agreement or other instrument or obligation to
which Southwest or Merger Sub is a party, or by which they or their respective
properties or assets may be bound or affected, except with respect to (iii)
above, for such violations, conflicts, breaches, defaults, terminations,
accelerations or encumbrances which in the aggregate will not prevent or delay
the consummation of the transactions contemplated hereby.

                  4.4 Consents and Approvals. Except for consents and approvals
of or filings or registrations with the SEC, the FTC, the Justice Department and
other applicable federal and state governmental authorities, no consents or
approvals of or filings or registrations with any third party or any public body
or authority are necessary in connection with the execution and delivery by
Southwest or Merger Sub of this Agreement.

                  4.5 Sufficient Resources. Southwest will have available at the
Closing sufficient common stock to enable it lawfully to satisfy its payment
obligations pursuant to

                                       26
   31

this Agreement subject to approval by the California Public Utilities
Commission. Upon issuance as provided in this Agreement, the Southwest Common
Stock will be duly and validly issued, fully paid and nonassessable and will be
owned by the NPL Shareholders free and clear of any liens or encumbrances.
Southwest has and will have sufficient management and financial resources to
make reasonable efforts to obtain the required regulatory approvals for the
Merger. On the date of this Agreement, there is no pending or, to the knowledge
of Southwest, threatened legal or governmental proceeding against Southwest or
any subsidiary or affiliate thereof which would affect Southwest's ability to
obtain any of the required regulatory approvals or satisfy any of the other
conditions required to be satisfied in order to consummate the transactions
contemplated by this Agreement. Southwest will promptly notify NPL if any of the
representations contained in this Section 4.5 ceases to be true and correct.

                  4.6 Litigation. No action, suit, counterclaim or other
litigation, investigation or proceeding to which Southwest or any of its
subsidiaries is a party is pending, or is known by the executive officers of
Southwest or any of its subsidiaries to be threatened, against Southwest or any
of its subsidiaries before any court or governmental or administrative agency,
domestic or foreign which would be reasonably expected to result in any
liabilities which would delay or prevent the consummation of the Merger. Except
as disclosed herein or the Southwest Reports (as hereinafter defined),

                           (i) There are no legal, administrative, arbitration
                  or other proceedings or claims pending or, to the best of
                  Southwest's knowledge, threatened against Southwest, nor is
                  Southwest subject to any existing judgment which

                                       27
   32

                  would materially affect the consolidated financial condition
                  or results of operations of Southwest;

                           (ii) Southwest has not received any inquiry from an
                  agency of the federal or of any state or local government
                  about the transactions contemplated hereby, or about any
                  violation or possible violation of any law, regulation or
                  ordinance materially affecting its businesses or assets.

                  4.7 Capitalization. Southwest is authorized to issue thirty
million (30,000,000) shares of Southwest Common Stock, $1.00 par value. As of
November 1, 1995, there were twenty-four million three hundred twenty thousand
two hundred eighty-eight (24,320,288) shares of Southwest Common Stock issued
and outstanding, and no other outstanding rights to purchase any common stock of
Southwest existed except under the Southwest Dividend Reinvestment and Stock
Purchase Plan, Employees' Investment Plan and Management Incentive Plan.

                  4.8 SEC Filings. Southwest has provided the NPL Shareholders
with true and correct copies of (i) Southwest's Annual Report on Form 10-K for
the fiscal year ended December 31, 1994; (ii) Southwest's Annual Report to
Stockholders for the fiscal year ended December 31, 1994; (iii) Southwest's
proxy statement for its 1995 Annual Meeting of Shareholders; (iv) Southwest's
Quarterly Reports on Form 10-Q for the fiscal quarters ended March 31, 1995,
June 30, 1995 and September 30, 1995; and (v) any other filings made with the
SEC pursuant to the Securities Exchange Act of 1934 (the "1934 Act") since
January 1, 1995. Between the date hereof and the Closing Date, Southwest will
provide to the NPL Shareholders true and correct copies of all further filings
made with the SEC

                                       28
   33


pursuant to the 1934 Act, as well as all reports or other communications sent to
Southwest's shareholders generally as soon as reasonably available. All of the
foregoing reports, filings, statements and communications are hereinafter
collectively referred to as the "Southwest Reports." None of the Southwest
Reports, when filed or sent, did or will contain any untrue statement of a
material fact or omit to state any material fact required to be stated therein
or necessary to make the statements made therein, in light of the circumstances
under which they were made, not misleading.

                  4.9 Business Changes. Except as set forth herein or in the
Southwest Reports, since September 30, 1995, there has not been:

                           (i) Any material adverse change in the consolidated
                  working capital, financial condition, assets, liabilities
                  (whether absolute, accrued, contingent or otherwise), or
                  operating profits, of Southwest or any material adverse change
                  in the business of Southwest taken as a whole;

                           (ii) Any damage, destruction or loss (whether or not
                  covered by insurance) materially and adversely affecting the
                  business of Southwest taken as a whole; or

                           (iii) Any termination of any material permit or
                  material license issued to Southwest or to any of its
                  employees or agents upon which a material portion of
                  Southwest's business is dependent.

                  4.10 Financial Statements.

                  (a) The consolidated financial statements of Southwest
         included within the Southwest Reports fairly present the consolidated
         financial position of

                                       29
   34

         Southwest and the consolidated results of its operations at the dates
         and for the periods to which they apply; such statements have been
         prepared in conformity with generally accepted accounting principles,
         applied on a consistent basis throughout the periods involved, and such
         financial statements comply with all applicable provisions of
         Regulation S-X of the SEC. The interim consolidated financial
         statements presented in such Reports include all adjustments (subject
         only to normal recurring year-end adjustments) necessary for a fair
         presentation of Southwest's consolidated financial position and
         consolidated results of operations as of the dates and for the periods
         presented therein.

                  (b) On September 30, 1995, Southwest had no material
         liabilities (whether absolute, accrued, contingent or otherwise) which
         were required to be reflected in and disclosed on its balance sheets at
         that date or in the notes thereto pursuant to Regulation S-X of the SEC
         or in accordance with generally accepted accounting principles,
         consistently applied but were not so reflected. Except as set forth
         herein and/or the Southwest Reports, since September 30, 1995,
         Southwest has incurred no material liabilities (whether absolute,
         accrued, contingent or otherwise) in addition to those reflected in or
         disclosed on such balance sheets or the related notes, except
         liabilities incurred in the ordinary course of its business.

                  (c) Southwest's books, records and system of internal
         accounting controls comply in all material respects with Section 13(b)
         of the 1934 Act as in effect on the date hereof.

                  4.11 Disclosure. To the knowledge of Southwest, no
representation or

                                       30
   35

warranty made by Southwest in this Agreement and no certification furnished or
to be furnished by Southwest to NPL pursuant to this Agreement, contains any
untrue statement of a material fact or omits to state a material fact necessary
to make the statements contained herein or therein in the light of the
circumstances under which it was made, not misleading.

         5.       Covenants of the Parties.

                  5.1      Current Information.

                  (a) No later than ten (10) days after the date of this
         Agreement, NPL (on the one hand) and Southwest (on the other hand)
         shall each designate an individual acceptable to the other party (a
         "Designated Representative" and, together, the "Designated
         Representatives") to be the primary point of contact between the
         parties. During the period from the date of their designation to the
         Closing, the Designated Representatives or their representatives shall
         confer on a regular basis so that Southwest is kept advised as to the
         general status of the ongoing operations of NPL. Without limiting the
         foregoing, NPL agrees to confer with Southwest's Designated
         Representative regarding any proposed significant changes to NPL's
         management policies and objectives. NPL will promptly notify
         Southwest's Designated Representative or his or her representatives of
         any material change in the normal course of business or in the
         operation of the properties of NPL or of any governmental complaints,
         investigations or hearings (or communications indicating that the same
         may be contemplated) or the institution or the threat of any litigation
         involving NPL, and will keep Southwest's Designated

                                       31
   36

         Representative or his or her representatives fully informed of such
         events and the progress of any already existing litigation.

                  (b) Southwest shall immediately notify NPL's Designated
         Representative if it appears that there has occurred any change in its
         financial or other condition or any other event that will or may affect
         Southwest's ability to complete the Merger.

                  5.2 NPL Reports. As soon as reasonably available, but in no
event more than 20 calendar days after the end of each accounting month, NPL
will deliver to Southwest its monthly financial reports. As soon as reasonably
available, but in no event more than 120 days after the end of the 1995 fiscal
year, NPL will deliver to Southwest its annual audited financial statements.

                  5.3 Regulatory Matters.

                  (a) The parties hereto will cooperate with each other and use
         all reasonable efforts to prepare all necessary documentation, to
         effect all necessary filings and to obtain all necessary permits,
         consents, approvals and authorizations of all third parties and
         governmental bodies necessary to consummate the transactions
         contemplated by this Agreement including, without limitation, those
         that may be required from the SEC, the FTC, the Justice Department and
         other federal and state regulatory authorities. Southwest and NPL will
         each have the right to review reasonably in advance all information
         relating to themselves and any of their respective subsidiaries,
         together with any other information reasonably requested, which appears
         in any filing made with or written material submitted to any
         governmental body in connection with the transactions contemplated by
         this

                                       32
   37

         Agreement. The parties hereto agree to attempt to keep confidential any
         and all proprietary information which may be of value to their
         competition.

                  (b) Southwest and NPL shall furnish each other with all
         reasonable information concerning themselves, their subsidiaries,
         directors, officers and stockholders and such other matters as may be
         necessary or advisable in connection with any statement or application
         made by or on behalf of Southwest or NPL, or any of Southwest's
         subsidiaries to any governmental body in connection with the Merger and
         the other transactions, applications or filings contemplated by this
         Agreement.

                  (c) Southwest and NPL will promptly furnish each other with
         copies of written communications received by or delivered to any
         governmental body in respect of the transactions contemplated hereby.

                  5.4 Further Assurances. Subject to the terms and conditions
herein provided, each of the parties hereto agrees to use all reasonable efforts
to take, or cause to be taken, all action and to do, or cause to be done, all
things necessary, proper or advisable under applicable laws and regulations to
consummate and make effective the transactions contemplated by this Agreement.
In case that at any time after the Closing any further action is necessary or
desirable to carry out the purposes of this Agreement, the proper officers and
directors of Southwest and NPL shall take all necessary actions, subject to the
terms and conditions of this Agreement.

                  5.5 Public Announcements. The parties will cooperate and
consult with each other in the development and distribution of all news releases
and other public

                                       33
   38

information disclosures with respect to this Agreement or any of the
transactions contemplated hereby, except as may be otherwise limited by law.

                  5.6 Failure to Fulfill Conditions. In the event that either
Southwest or NPL determines that a condition to its obligation to consummate the
transactions contemplated hereby cannot be, or is not likely to be, fulfilled on
or prior to May 15, 1996, it will promptly notify the other party.

                  5.7 Tax Matters.

                  (a)      Return Preparation; Tax Payments.

                           (i) NPL shall prepare, or cause to be prepared, and
                  shall file, or cause to be filed, any required NPL tax returns
                  (including amendments thereto) for all taxable periods prior
                  to and including the Closing Date. NPL shall consult with
                  Southwest regarding the preparation and filing of such returns
                  and Southwest shall be afforded the opportunity to review such
                  returns within a reasonable time prior to the due date for the
                  filing thereof. NPL shall not file any such tax returns
                  without the prior consent of Southwest, which consent shall
                  not be unreasonably withheld or delayed. NPL shall also
                  provide Southwest with copies of such returns in the form
                  actually filed and copies of all backup documentation.

                           Southwest shall be responsible for the preparation
                  and filing of any tax returns of NPL for all taxable periods
                  beginning after the Closing Date.

                           (ii) As soon as practicable after the filing of these
                  returns, but in no event later than April 1, 1996, for the
                  1995 return, and within four months

                                       34
   39

                  of the Closing Date for the 1996 return, NPL or Surviving
                  Corporation shall pay to NPL Shareholders, in cash, 46 percent
                  of their share of the Subchapter S taxable income for such
                  periods as reflected on the applicable Internal Revenue
                  Service Form 1120S and related Schedule K-1.

                           (iii) Southwest hereby consents to and approves the
                  change by NPL from the cash to the accrual method for tax
                  reporting purposes, effective with the tax year beginning
                  January 1, 1996, and the filing with the I.R.S. of whatever
                  documents are required for such change.
                 
                  (b) Tax Audits and Litigation.

                           (i) Representation Prior to Closing Date. Prior to
                  the Closing Date, NPL shall conduct and control the
                  representation of NPL with respect to any audit or
                  administrative or judicial proceeding concerning any tax items
                  or taxable period of NPL, including, without limitation, the
                  sole right to contest or concede any tax item, provided,
                  however, that NPL shall first obtain the consent of Southwest
                  with respect to any settlement or concession, which consent
                  shall not be unreasonably withheld or delayed, and shall
                  afford the opportunity, at Southwest's request, for Southwest
                  to participate fully in all settlement or concession
                  discussions relating to any taxable periods ending on or prior
                  to Closing.

                           (ii) Representation After Closing Date. For any
                  taxable period ending on or before the Closing, Noel T. Coon
                  shall be entitled, at his option and at his expense, to
                  conduct and exercise sole control over the

                                       35
   40

                  representation of NPL with respect to any audit or
                  administrative or judicial proceedings, including, without
                  limitation, the sole right to contest or concede any tax
                  items, provided, however, that Noel T. Coon shall first obtain
                  the consent of Southwest with respect to any settlement or
                  concession, which consent shall not be unreasonably withheld
                  or delayed, and shall afford Southwest the opportunity, at its
                  request, to participate fully in all settlement or concession
                  discussions. 

                  (c) Tax Workpapers. At the time of closing, NPL will provide
         Southwest copies of all tax returns, associated workpapers, documents,
         memoranda and correspondence prepared by NPL's tax preparers and made
         available to NPL for the tax period ended September 30, 1987 and for
         each tax period thereafter through the tax period ending with the
         closing of this Agreement.

         6.       Covenants of NPL.

                  6.1 Conduct of the Business of NPL. During the period from the
date hereof to the Closing, except as otherwise permitted or required hereunder,
NPL will conduct the business of NPL and will engage in transactions only in the
ordinary course and consistent with the past practice and with prudent business
practice, except with the written consent of Southwest (which will not be
unreasonably withheld, delayed or conditioned). For this purpose the parties
shall use the most expeditious means of communication available. During such
period, NPL will use its reasonable efforts in accordance with good business
practice to preserve the business organization of NPL, to keep available to it
and to Southwest the present services of the valued employees of NPL,

                                       36
   41

and to preserve for itself and for Southwest the goodwill of the customers of
NPL and others with whom business relationships exist. In addition, without
limiting the generality of the foregoing, NPL agrees that from the date hereof
to the Closing, except as otherwise consented to or approved by Southwest in
writing (which consent or approval shall not be unreasonably withheld, delayed
or conditioned) or as permitted or required by this Agreement or as required by
law (in which case NPL shall notify Southwest in writing), NPL will not:

                  (a) Change any provisions of NPL's Articles or Bylaws;

                  (b) Change the number of shares of authorized or issued
         capital stock of NPL or issue, or grant any option, warrant, call,
         commitment, subscription, right to purchase or agreement of any
         character relating to the authorized or issued capital stock of NPL, or
         any securities convertible into shares of such stock, or split, combine
         or reclassify any shares of its capital stock, or declare, set aside or
         pay any dividend, or other distributions (whether in cash, stock or
         property or any combination thereof) in respect of the capital stock of
         NPL, or redeem or otherwise acquire any shares of such capital stock
         except as permitted by Section 6.1(m) and except for the issuance of
         additional shares and the declaration and payment of a dividend in the
         form of a Dividend Note in connection with the exercise of stock
         options by Messrs. Johnson and Kemper under the Stock Purchase
         Agreement dated March 7, 1994, as amended by Amendment to Stock
         Purchase Agreement dated November 12, 1995;

                  (c) Grant any severance or termination pay to or enter into or
         amend any

                                       37
   42

         employment agreement with, or increase the amount of payments or fees
         to, any of the employees, officers or directors of NPL except for (i)
         the payments to Messrs. Sutton and Maple listed on Schedule
         3.11(c)(viii), (ii) severance payments under union agreements, (iii)
         miscellaneous other severance payments not known, but not to exceed a
         total of $10,000, (iv) normal salary increases, such as merit,
         promotion, etc., consistent with past practice;

                  (d) Except as listed on Disclosure Schedule 6.1(d), make any
         capital expenditures, including any capitalizable lease obligations, in
         amounts individually in excess of (i) $100,000 or (ii) $250,000 in the
         aggregate, other than expenditures necessary to maintain existing
         assets in good repair;

                  (e) Make or engage in any financing-related transactions other
         than (i) scheduled principal and interest payments on long-term debt,
         capital lease obligations, equipment leases, and the note payable to
         the current stockholder, (ii) transactions necessary to finance,
         consistent with past practices and with prudent business practices,
         capital expenditures made in accordance with the provisions of Section
         6.1(d) hereof, and (iii) borrowings and payments under the working
         capital lines of credit, in the ordinary course of business. Scheduled
         principal and interest payments are listed on Disclosure Schedule
         6.1(e).

                  (f) Make application for the opening of, or open, any new
         offices involving a lease in excess of one year;

                  (g) Acquire assets other than those necessary to the conduct
         of its business in the ordinary course;

                                       38
   43

                  (h) Sell, transfer, assign, encumber or otherwise dispose of
         assets other than has been customary in the ordinary course of
         business;

                  (i) Engage or participate in any material transaction or incur
         or sustain any obligation which would result in a cost to NPL,
         individually or cumulatively of more than $10,000 (a "Material
         Obligation") except for transactions which are in the ordinary course
         of business consistent with past practices and with prudent business
         practices and which are of similar kinds and involve similar amounts;

                  (j) Make any contributions to any Benefit Plans except in such
         amounts and at such times as consistent with past practice;
         discretionary or excess contributions are not permitted;

                  (k) Increase the number of full-time equivalent employees of
         NPL from July 31, 1995 except as consistent with past practice;

                  (l) Make or grant any safety or other bonuses to any employee
         or shareholder, except for bonuses payable to Mr. Johnson or Mr. Kemper
         under their existing respective employment contracts and other bonuses
         consistent with past practices;

                  (m) Make or grant any distributions to any shareholder other
         than customary salary and related benefits except the following:

                           (i) Bonuses to Mr. Johnson and Mr. Kemper in
                  accordance with their existing respective employment
                  contracts;

                           (ii) Distributions to NPL Shareholders sufficient for
                  the payment of their 1995 and 1996 federal and state income
                  taxes on the taxable income

                                       39
   44

                  of NPL;

                           (iii) A distribution to Noel T. Coon as a bonus for
                  1995, computed as fifty percent (50%) of the amount by which
                  the 1995 pretax income of NPL determined in accordance with
                  generally accepted accounting principles consistently applied
                  exceeds four million dollars ($4,000,000), said bonus not to
                  exceed six hundred thousand dollars ($600,000); and

                           (iv) The Dividend Note to Noel T. Coon and the
                  transfer of the Option Notes in payment of the Dividend Note
                  to Noel T. Coon in connection with the exercise of the Johnson
                  and Kemper option exercises as described in Section 3.2.

                  (n)      Agree to do any of the foregoing.

                  6.2 No Solicitation. During the term hereof, neither NPL nor
any of its directors, shareholders, officers, representatives, agents or other
persons controlled by any of them, shall, directly or indirectly, encourage or
solicit, or hold discussions or negotiations with, or provide any information
to, any person, entity or group other than Southwest concerning any merger, sale
of substantial assets not in the ordinary course of business, sale of shares of
capital stock or similar transactions involving NPL. NPL will promptly
communicate to Southwest the terms of any proposal that it may receive in
respect of any such transaction.

                  6.3 Access to Management, Properties and Records;
Confidentiality.

                  (a) NPL shall permit Southwest reasonable access to the
         properties of NPL, and shall disclose and make available to Southwest
         all books, papers and

                                       40
   45

         records relating to the assets, stock, ownerships, properties,
         obligations, operations and liabilities of NPL, including but not
         limited to, all books of account (including the general ledger), tax
         records, budgets, forecasts, minute books of directors' and
         stockholders' meetings, organizational documents, bylaws, material
         contracts and agreements, internal audit reports, filings with any
         regulatory authority, company work papers and supporting documents,
         accountants' work papers, litigation files, plans affecting employees,
         and any other business activities or prospects in which Southwest may
         have a reasonable interest, in each case during normal business hours
         and upon reasonable notice. Between the signing of this Agreement and
         the Closing, the parties shall cooperate in accordance with the
         Memorandum of Mr. Johnson dated November 3, 1995 which is attached
         hereto as Exhibit A.

                  (b) All information furnished by NPL to Southwest or the
         representatives or affiliates of either pursuant to, or in any
         negotiation in connection with, this Agreement shall be treated as the
         sole property of NPL, until consummation of the Merger and, if the
         Merger shall not occur, Southwest and its affiliates, agents and
         advisers shall destroy or return to NPL, as appropriate, all documents
         or other materials containing, reflecting or referring to such
         information, and shall keep confidential all such information and shall
         not disclose or use such information for competitive purposes. Any
         destruction or return shall be certified in writing to the appropriate
         party. The obligation to keep such information confidential shall not
         apply to any information which Southwest can establish by convincing
         evidence was already in its possession (subject to no obligations of
         confidentiality) prior to

                                       41
   46

         the disclosure thereof by NPL; was then generally known to the public;
         becomes known to the public other than as a result of actions by
         Southwest or by its directors, officers or employees or agents; or was
         disclosed to Southwest or to its directors, officers or employees,
         solely by a third party not bound by any obligation of confidentiality.

                  6.4 Assignment of Contract Rights. NPL shall obtain any
consents, waivers or revisions necessary to allow Merger Sub to accede to all of
the rights of NPL under all existing real property and personal property leases,
lines of credit, governmental licenses, permits and other contracts. Any costs
associated with obtaining such consents, waivers and revisions shall be borne by
NPL.

         7.       Employees; Employee Benefit Plans.

                  7.1      Covenants of NPL.

                  (a) Prior to Closing, NPL shall deliver or make available to
         Southwest complete and correct copies (if any) of (i) the most recent
         Internal Revenue Service determination letter relating to each Employee
         Pension Benefit Plan intended to be tax qualified under Sections 401(a)
         and 501(a) of the Code, (ii) the most recent annual report (Form 5500
         Series) and accompanying schedules of each Benefit Plan, filed with the
         Internal Revenue Service or an explanation of why such annual report is
         not required, (iii) the most current summary plan description for each
         Benefit Plan, and (iv) the most recent audited financial statements of
         each Benefit Plan.

                  (b) Except as otherwise provided in this Agreement, NPL shall
         not

                                       42
   47

         establish, amend or terminate any Benefit Plan without the prior
         consultation and approval of Southwest.

         8.       Closing Conditions.

                  8.1 Conditions to Each Party's Obligations Under This
Agreement. The respective obligations of each party under this Agreement to
consummate the Merger shall be subject to the fulfillment at or prior to the
Closing of the following conditions:

                  (a) All necessary regulatory or governmental approvals and
         consents required to consummate the transactions contemplated hereby
         shall have been obtained and shall remain in full force and effect and
         all statutory or regulatory waiting periods in respect thereof shall
         have expired.

                  (b) No party hereto shall be subject to any order, decree or
         injunction of a court or agency of competent jurisdiction which enjoins
         or prohibits the consummation of the Merger.

                  (c) Any applicable pre-merger/acquisition notification
         provisions of Section 7A of the Clayton Act shall have been complied
         with by the parties hereto, and no other statutory or regulatory
         requirements with respect to the Clayton Act shall be applicable. There
         shall be no pending or threatened proceedings with respect to this
         Agreement or the Merger under any applicable antitrust law.

                  8.2 Conditions to the Obligations of Southwest under this
Agreement. The obligations of Southwest under this Agreement shall be further
subject to the satisfaction, at or prior to the Closing, of the following
conditions, any one or more of which may be waived by Southwest:

                                       43
   48

                  (a) Each of the obligations or covenants of NPL required to be
         performed by them at or prior to the Closing pursuant to the terms of
         this Agreement shall have been duly performed and complied with in all
         material respects and each of the representations and warranties of NPL
         contained in this Agreement shall be true and correct in all material
         respects as of the date hereof and as of the Closing as though made at
         and as of the Effective Time (except as to any representation or
         warranty that specifically relates to an earlier date, which shall be
         true and correct as of such earlier date), provided, however, that if
         any representation or warranty has proved untrue or incorrect in any
         material respect and the damage or loss resulting from such failure can
         be reduced to a dollar amount to which Noel T. Coon and Southwest
         agree, then such representation or warranty shall, for purposes of this
         closing condition, be deemed to be true and correct in all material
         respects at Closing, and the total Fair Market Value of the Southwest
         Common Stock to be delivered hereunder shall be reduced by such agreed
         amount.

                  (b) Any consents, waivers, clearances, approvals and
         authorizations of regulatory or governmental bodies or third parties
         that are necessary in connection with the consummation of the
         transactions contemplated hereby shall have been obtained, and none of
         such consents, waivers, clearances, approvals or authorizations shall
         contain any term or condition that would have a Material Adverse Effect
         on NPL or Southwest or the Surviving Corporation. For purposes of
         Section 8 hereof, any "approval" which contains any of the foregoing
         unacceptable terms or conditions shall be deemed to be a regulatory
         "denial."

                                       44
   49

                  (c) Southwest shall have received an opinion, dated the date
         of the Closing, from Squire, Sanders & Dempsey and/or Arnold R.
         Madigan, counsel to NPL, substantially to the effect set forth in
         Exhibit B hereto.

                  (d) Since the date of this Agreement, there shall have been no
         material adverse change in the overall financial condition, business or
         results of operations of NPL taken as a whole. Normal seasonal
         variations are deemed not to be such a material adverse change.

                  (e) Except as otherwise requested, the directors of NPL shall
         have resigned effective on or prior to the Closing.

                  (f) NPL shall have furnished Southwest with such certificates
         of NPL officers and such other documents to evidence fulfillment of the
         conditions set forth in this Section 8.2 as Buyer may reasonably
         request.

                  8.3 Conditions to the Obligations of NPL Under This Agreement.
The obligations of NPL under this Agreement shall be further subject to the
satisfaction, at or prior to the Closing, of the following conditions, any one
or more of which may be waived by Noel T. Coon on behalf of NPL and NPL
Shareholders:

                  (a) Each of the obligations of Southwest required to be
         performed by it at or prior to the Closing pursuant to the terms of
         this Agreement shall have been duly performed and complied with in all
         material respects.

                  (b) Each of the representations and warranties of Southwest
         contained in this Agreement shall be true and correct in all material
         respects as of the date of this Agreement and as of the Closing as
         though made at and as of the Closing

                                       45
   50

         except as to any representation or warranty which specifically relates
         to an earlier date, which shall be true and correct as of such earlier
         date, except in the case of such representations and warranties, where
         the failure to be true would not have a Material Adverse Effect on
         Southwest.

                  (c) NPL shall have received an opinion, dated the date of the
         Closing, from Thomas J. Trimble, General Counsel to Southwest,
         substantially to the effect set forth in Exhibit C hereto.

                  (d) Southwest shall have furnished NPL with such certificates
         of its officers or others and such other documents to evidence
         fulfillment of the conditions set forth in this Section 8.3 as NPL may
         reasonably request.

                  (e) NPL shall have received the opinion of Deloitte & Touche
         LLP that the merger qualifies as a tax-free reorganization under
         Section 368(a)(2)(D) of the Code and the Regulations thereunder.

                  (f) Since the date of this Agreement, there shall have been no
         material adverse change in the overall financial condition, business or
         results of operations of Southwest taken as a whole. Normal seasonal
         variations are deemed not to be such a material adverse change.

         9.       Closing.

                  9.1 Date and Place. The closing of the Merger (the "Closing")
shall take place on the last day of the four or five week accounting period of
NPL, as applicable, during which all of the conditions to the obligations of the
parties hereunder, other than those to be performed at Closing, have been
satisfied or waived (the "Closing Date"); 

                                       46
   51

provided, however, that if the Closing Date in accordance with the foregoing
provisions of Section 9.1 would be less than five trading days prior to the end
of such accounting period, the Closing Date shall be the last day of the next
succeeding four or five week accounting period of NPL, as applicable. All
actions taken at the Closing shall be deemed to have occurred simultaneously at
the Effective Time. The Closing shall take place at the offices of Southwest in
Las Vegas, Nevada, or at such other place as the parties hereto may mutually
agree.

                  9.2 NPL's Closing Documents. At the Closing, NPL shall deliver
to Southwest:

                  (a) One or more stock certificates registered in the name(s)
         of NPL Shareholders representing all of the issued and outstanding
         shares of NPL Capital Stock, duly endorsed on behalf of NPL
         Shareholders;

                  (b) Such other documents and instruments as required by
         Section 8 to be delivered by NPL or NPL Shareholders.

                  9.3 Southwest's Closing Documents. At the Closing, Southwest
and Merger Sub shall deliver to NPL Shareholders:

                  (a) The Purchase Price of twenty-four million dollars
         ($24,000,000), payable in Southwest's Common Stock as provided for in
         this Agreement; and

                  (b) Such other documents and instruments as required by
         Section 8 to be delivered by Southwest.

         10.      Post-Closing Obligations.

                  10.1     Registration of Southwest Common Stock.


                                       47

   52

                  (a) As soon as practicable after the Closing Date, but in no
         event more than 30 days thereafter, Southwest shall (i) file a Form S-3
         registration statement pursuant to the Securities Act of 1933, as
         amended (the "Securities Act"), under Rule 415 thereunder, that
         includes all shares of Southwest Common Stock acquired by the NPL
         Shareholders in the Merger ("Acquired Stock"); (ii) file a request for
         exemption under Section 359-f(2) of the Fraudulent Practices Act
         ("Martin Act") with the Bureau of Investor Protection and Securities,
         Department of Law, State of New York; and (iii) take such other action
         as may be necessary to register or qualify the offer and sale of the
         Acquired Stock in any other state in which its Common Stock does not
         qualify as an "exempt security." Southwest agrees that it will use
         reasonable efforts to cause the Form S-3 registration statement to be
         declared effective by the SEC and the request for exemption to be
         granted by the Department of Law of the State of New York and to
         complete any other action which may be necessary to register or qualify
         the offer and sale of the Acquired Stock as provided in clause (iii)
         above. All expenses (exclusive of underwriting discounts and
         commissions and expenses for registration or licensing of the NPL
         Shareholders as a broker-dealer, dealer, salesperson, agent or
         associated person, if any, and fees and expenses of counsel for the NPL
         Shareholders) incurred in connection with such registration, request
         for exemption and actions shall be borne by Southwest. No transferee of
         the Acquired Stock shall be entitled to the rights and benefits of this
         Section 10.1, except transferees under Section 10.2(a)(ii).

                  (b) It shall be a condition precedent to the obligations of
         Southwest to file 



                                       48
   53
         a registration statement or to register any securities pursuant to
         Section 10.1(a) that the NPL Shareholders furnish Southwest such
         undertakings as may be required by the Securities Act and other
         applicable law to permit the registration statement to be filed in
         accordance with Rule 415 under the Securities Act, and such information
         regarding the NPL Shareholders, the Acquired Stock, the intended
         method(s) of disposition of such securities and such other information
         (other than information known to Southwest with respect to contractual
         arrangements between the NPL Shareholders and Southwest) as, in the
         reasonable opinion of counsel to Southwest, is necessary to enable
         Southwest to cause such registration statement to be properly prepared
         and filed in accordance with applicable laws and to obtain acceleration
         of the effective date thereof. All underwriting discounts and
         commissions and expenses for registration or licensing of the NPL
         Shareholders as a broker-dealer, dealer salesperson, agent or
         associated person under state blue sky or securities laws, if any,
         shall be borne by the NPL Shareholders.

                  (c) Southwest agrees that it will keep each NPL Shareholder
         advised in writing as to the completion of any registrations or
         qualifications pursuant to this Section 10.1 and will, at its expense:
         (i) use reasonable efforts to keep such registrations and
         qualifications effective under the Securities Laws until such time as
         the Acquired Stock can be sold by the NPL Shareholders within the
         applicable volume limitation of Rule 144(e) or without any volume
         limitation in compliance with Rule 144(k), whichever first occurs (the
         "Restriction Lapse Date"); and (ii) furnish such number of prospectuses
         and other documents incident thereto as any NPL 



                                       49
   54
         Shareholder from time to time may reasonably request. If, in the
         opinion of counsel to Southwest, the Form S-3 registration statement
         filed pursuant to Section 10.1(a) cannot be maintained in effect until
         the Restriction Lapse Date, then, not later than twenty (20) days prior
         to the expiration of the effectiveness of such Form S-3 registration
         statement, Southwest shall file another Form S-3 registration statement
         covering the remaining Acquired Stock, and shall use reasonable efforts
         to cause such registration statement to be declared effective and
         maintained in effect until the Restriction Lapse Date. In connection
         therewith, Southwest shall take the same actions with respect to such
         new registration statement and the registration and qualification of
         the remaining Acquired Stock under the Securities Laws as was required
         hereunder with respect to the original Form S-3 registration statement
         and the original registration and qualification of the Acquired Stock.

                  (d) If, at any time during the effectiveness of a Form S-3
         registration statement filed hereunder, Southwest shall notify the NPL
         Shareholders that the prospectus contained therein contains an untrue
         statement of material fact or omits to state a material fact necessary
         to make the statements made therein not misleading, each NPL
         Shareholder agrees not to sell any of the Acquired Stock pursuant to
         such Form S-3 registration statement thereafter until such time as
         Southwest notifies the NPL Shareholders that such material misstatement
         or omission has been corrected through the filing of an appropriate
         supplement to such prospectus, the filing and effectiveness of an
         amendment to such registration statement, or the filing of a document
         incorporated by reference therein. Southwest 


                                       50
   55
         shall use its reasonable efforts to file any such required
         supplement, amendment (and to have any such amendment declared
         effective) or such document as promptly as practicable; provided,
         however, that such filing may be delayed during any period of time that
         the executive officers and directors of Southwest have been asked to
         refrain from selling, offering to sell or otherwise disposing of any
         shares of its Common Stock or contracting to sell or otherwise
         disposing of any securities convertible into or exercisable or
         exchangeable for Common Stock.

                  (e) To the extent permitted by law, Southwest will indemnify
         and hold harmless each NPL Shareholder, any underwriter (as defined in
         the Securities Act) for any such NPL Shareholder and each person, if
         any, who controls such NPL Shareholder or underwriter within the
         meaning of the Securities Act or the 1934 Act (collectively, the "NPL
         Indemnified Parties") against any losses, claims, damages, or
         liabilities (joint or several) to which they or any of them may become
         subject under the Securities Act, the 1934 Act or any other federal or
         state law (the "Securities Laws"), insofar as such losses, claims,
         damages, or liabilities (or actions in respect thereof) arise from or
         are based upon any of the following statements, omissions or violations
         (collectively, a "Violation"): (i) any untrue statement or alleged
         untrue statement of a material fact contained in such registration
         statement, including any preliminary prospectus or final prospectus
         contained therein or any amendments or supplements thereto; (ii) the
         omission or alleged omission to state therein a material fact required
         to be stated therein, or necessary to make the statements therein not
         misleading; or (iii) any violation or alleged violation by 



                                       51
   56
         Southwest of the Securities Laws; and Southwest will reimburse such NPL
         Indemnified Parties for any legal or other expenses reasonably incurred
         by them in connection with investigating or defending any such loss,
         claim, damage, liability or action; provided, however, that the
         indemnity agreement contained in this Section 10.1(e) shall not apply
         to amounts paid in settlement of any such loss, claim, damage,
         liability or action if such settlement is effected without the consent
         of Southwest (which consent shall not be unreasonably withheld), nor
         shall Southwest be liable in any case for any such loss, claim, damage,
         liability, or action to the extent that it arises from or is based upon
         a Violation which occurs in reliance upon and in conformity with
         written information furnished expressly for use in connection with such
         registration by any such NPL Indemnified Parties.

                  (f) To the extent permitted by law, each NPL Shareholder will
         indemnify and hold harmless Southwest, each of its directors, each of
         its officers who have signed the registration statement, each person,
         if any, who controls Southwest within the meaning of the Securities
         Act, any underwriter within the meaning of the Securities Act or the
         1934 Act for Southwest, any person who controls such underwriter, and
         any other person or entity selling securities in such registration
         statement, if any (the "Other Selling Stockholders") or any of such
         Other Selling Stockholders' directors, officers, partners, general
         partners or any person who controls such Other Selling Stockholders
         (collectively, the "Southwest Indemnified Parties") against any losses,
         claims, damages or liabilities (joint or several) to which any such
         Southwest Indemnified Parties may become subject under the Securities




                                       52
   57
         Laws, insofar as such losses, claims, damages or liabilities (or
         actions in respect thereto) arise from or are based upon any Violation,
         in each case to the extent (and only to the extent) that such Violation
         occurs in reliance upon and in conformity with written information
         furnished by such NPL Shareholder in connection with such registration;
         and such NPL Shareholder will reimburse any legal or other expenses
         reasonably incurred by any Southwest Indemnified Parties in connection
         with investigating or defending any such loss, claim, damage,
         liability, or action; provided, however, that the indemnity agreement
         contained in this Section 10.1(f) shall not apply to amounts paid in
         settlement of any such loss, claim, damage, liability or action if such
         settlement is effected without the consent of such NPL Shareholder,
         which consent shall not be unreasonably withheld.

                  (g) Promptly after receipt by any party entitled to
         indemnification under this Section 10.1 (an "Indemnified Party") of
         notice of the commencement of any action (including any governmental
         action ), such Indemnified Party will, if a claim in respect thereof is
         to be made under this Section 10.1 against any party required to
         indemnify such Indemnified Party (an "Indemnifying Party"), notify the
         Indemnifying Party in writing of the commencement thereof and the
         Indemnifying Party shall have the right to participate in, and, to the
         extent the Indemnifying Party so desires, jointly with any other
         Indemnifying Party similarly noticed, to assume the defense thereof
         with counsel mutually satisfactory to the parties; provided, however,
         that an Indemnified Party shall have the right to retain its own
         counsel, with the fees and expenses to be paid by the Indemnifying
         Party, if representation of such 


                                       53
   58
         Indemnified Party by the counsel retained by the Indemnifying Party
         would be inappropriate due to actual or potential differing interests
         between such Indemnified Party and any other party represented by such
         counsel in such proceeding. The failure to notify an Indemnifying Party
         within a reasonable time of the commencement of any such action, to the
         extent prejudicial to its ability to defend such action, shall relieve
         such Indemnifying Party of any liability to the Indemnified Party under
         this Section 10.1, but the omission to so notify the Indemnifying Party
         will not relieve it of any liability that it may have to any
         Indemnified Party otherwise than under this Section 10.1.

                  10.2     Restrictions on Sale of Acquired Stock.

                  (a) For a period of two years from the Closing Date, Noel T.
         Coon agrees that he will not sell, dispose of or otherwise transfer
         more shares of Acquired Stock than he would be permitted to sell under
         the volume limitations of Rule 144 of the Securities Act as in effect
         on the date hereof, assuming that such volume limitation provisions of
         Rule 144 would be fully applicable to sales of Acquired Stock by Noel
         T. Coon for the duration of such two-year period. Notwithstanding the
         foregoing, to the extent permitted by applicable law, (i) Noel T. Coon
         shall be permitted to sell any amount of Acquired Stock held by him if
         (A) the most recent closing per share price of Southwest Common Stock
         prior to such sale as reported by the principal exchange on which such
         Common Stock is listed shall be less than $10 or (B) if Southwest
         publicly announces a plan or other agreement or arrangement providing
         for the merger of Southwest with or into another entity, the
         acquisition or other sale 


                                       54
   59
         of all or substantially all of the assets of Southwest (except for
         PriMerit Bank) by another entity or any other reorganization or
         business combination in which the Acquired Stock will be converted into
         cash or the securities of another person (collectively, an
         "Acquisition"); provided that if any Acquisition is submitted to a vote
         of the stockholders of Southwest, Noel T. Coon agrees to vote any
         shares of Acquired Stock he holds on the record date for determining
         stockholders entitled to vote on the Acquisition on a pro-rata basis
         with all other shareholders; and (ii) Noel T. Coon shall be permitted
         to transfer Acquired Stock by donation to any trust, foundation or
         charitable organization so long as such entity agrees to be bound by
         the provisions of Sections 10.2(b) and (c) hereof, in which event any
         sales of Acquired Stock by such entities shall be aggregated with any
         sales by Noel T. Coon in determining compliance herewith.

                  (b) Noel T. Coon agrees not to sell, either directly or
         indirectly, during any three-month period more than 240,000 shares of
         Acquired Stock to any one person or group, other than a broker-dealer
         who acquires the Acquired Stock for resale to any other person or group
         in a transaction which would not violate these provisions. Unless he
         has actual knowledge to the contrary, Noel T. Coon shall be entitled to
         rely upon a written representation from a purchaser that it is not
         acquiring the Acquired Stock in concert with any other person or with a
         view to resale in violation of these restrictions.

                  (c) The Acquired Stock acquired by Noel T. Coon shall bear the
         following legend:



                                       55
   60
                           THESE SECURITIES ARE SUBJECT TO RESTRICTIONS ON
                  TRANSFERABILITY AND RESALE AND MAY NOT BE TRANSFERRED OR
                  RESOLD EXCEPT AS PERMITTED UNDER THE SECURITIES ACT OF 1933,
                  AS AMENDED, AND APPLICABLE STATE SECURITIES LAWS, PURSUANT TO
                  REGISTRATION OR EXEMPTION. THESE SECURITIES ARE FURTHER
                  SUBJECT TO RESTRICTIONS ON TRANSFER SET FORTH IN THAT CERTAIN
                  MERGER AGREEMENT DATED AS OF NOVEMBER 13,1995.

                  (d) The Acquired Stock acquired by William L. Johnson and
         Michael J. Kemper shall bear the following legend:

                           THESE SECURITIES ARE SUBJECT TO RESTRICTIONS ON
                  TRANSFERABILITY AND RESALE AND MAY NOT BE TRANSFERRED OR
                  RESOLD EXCEPT AS PERMITTED UNDER THE SECURITIES ACT OF 1933,
                  AS AMENDED, AND APPLICABLE STATE SECURITIES LAWS, PURSUANT TO
                  REGISTRATION OR EXEMPTION THEREFROM.

                  This legend shall also appear on any Acquired Stock
         transferred by either Mr. Johnson or Mr. Kemper to a family trust or
         foundation.

         11.      Termination, Amendment and Waiver.

                  11.1 Termination. This Agreement may be terminated at any time
prior to the Closing, whether before or after approval of the Merger by the
governmental agencies:

                  (a) By mutual written consent of Southwest and Noel T. Coon
         (on behalf of NPL and NPL Shareholders);

                  (b) By either Southwest or Noel T. Coon (on behalf of NPL and
         NPL Shareholders) if all pre-closing conditions are not satisfied on or
         prior to May 15, 1996, unless (i) the failure of such occurrence shall
         be due to the failure of the party



                                       56
   61
         seeking to terminate this Agreement to perform or observe its
         agreements and conditions set forth herein to be performed or observed
         by such party at or before the Closing; or (ii) Southwest and Noel T.
         Coon (on behalf of NPL and NPL Shareholders) mutually agree to extend
         the time;

                  (c) By Southwest (i) if at the time of such termination there
         shall have been a material adverse change in the financial condition,
         business or operations of NPL taken as a whole from that set forth in
         the audited financial statements for the year ended December 31, 1994,
         it being understood that any of the matters set forth in NPL's
         Disclosure Schedules as of the date of this Agreement are not deemed to
         be a material adverse change for purposes of this paragraph (c); or
         (ii) if there shall have been any material breach of any covenant of
         NPL hereunder and such breach shall not have been remedied within 45
         days after receipt by NPL of notice in writing from Southwest
         specifying the nature of such breach and requesting that it be
         remedied;

                  (d) By Noel T. Coon (on behalf of NPL and NPL Shareholders)
         (i) if at the time of such termination there shall have been a material
         adverse change in the financial condition, business or result of
         operations of Southwest taken as a whole from that set forth in the
         audited financial statements for the year ended December 31, 1994; of
         (ii) if there shall have been any material breach of any covenant of
         Southwest hereunder and such breach shall have not been remedied within
         45 days after receipt by Southwest of notice in writing from NPL
         specifying the nature of such breach and requesting that it be
         remedied.


                                       57
   62
                  11.2 Amendment, Extension and Waiver. Subject to applicable
law, at any time prior to the consummation of the Merger, the parties may (a)
amend this Agreement, (b) extend the time for the performance of any of the
obligations or other acts of any other party hereto, (c) waive any inaccuracies
in the representations and warranties of any other party contained herein or in
any document delivered pursuant hereto, or (d) waive compliance with any of the
agreements or conditions contained herein. This Agreement may not be amended
except by an instrument in writing signed on behalf of each of the parties
hereto. Any agreement on the part of a party hereto to any extension or waiver
shall be valid only if set forth in an instrument in writing signed on behalf of
such party, but such waiver or failure to insist on strict compliance with such
obligation, covenant, agreement or condition shall not operate as a waiver of,
or estoppel with respect to, any subsequent or other failure.

         12.      Expenses.

                  (a) All expenses incurred by or on behalf of NPL in connection
         with the negotiation, authorization, preparation, execution and
         consummation of this Agreement (including the costs of complying with
         any covenants or conditions to Closing) and the transactions
         contemplated hereby (other than expenses incurred in connection with
         the operation of NPL in the ordinary course which would have been
         incurred notwithstanding the transactions contemplated hereby or
         thereby), including, without limitation, all fees and expenses of
         agents, representatives, accountants, investment bankers and counsel
         employed by NPL shall be borne solely by Noel T. Coon, except that NPL
         may pay up to $240,000 in 1995 and up


                                       58
   63
         to $160,000 in 1996 based on services rendered on the basis of the
         usual and customary hourly rates previously charged by its attorneys
         and accountants.

                  (b) All expenses incurred by or on behalf of Southwest in
         connection with the negotiation, authorization, preparation, execution
         and consummation of this Agreement and the transactions contemplated
         hereby and thereby, including, without limitation, all fees and
         expenses of agents, representatives, accountants, investment bankers
         and counsel employed by Southwest, shall be borne solely by Southwest.

         13. Indemnification.

                  13.1 Indemnification of Southwest. NPL Shareholders shall
indemnify Southwest and its officers, directors and subsidiaries from and
against all claims, losses, damages, costs, assessments, judgments, awards,
liabilities and expenses (including, without limitation, reasonable costs and
expenses of litigation, and, to the extent permitted by law, reasonable
attorneys' fees) incurred by Southwest or its officers, directors, agents or
subsidiaries by reason of:

                  (a) The untruthfulness or inaccuracy of any of the
         representations or warranties of NPL or the breach of any obligations
         of NPL contained in this Agreement.

                  (b) Any judgments, fines, penalties, settlement payments,
         settlement costs and attorneys' fees and expenses and interest related
         thereto entered, paid or incurred by NPL after July 31, 1995 in
         connection with any currently existing but undisclosed actions, suits,
         claims, inquiries, proceedings or investigations before



                                       59
   64
         any court, commission, bureau, regulatory, administrative or
         governmental agency, arbitrator body or authority in excess of $10,000
         in the aggregate and not reimbursed by insurance.

                  (c) Any liability of NPL, other than liabilities for benefits
         or contributions payable under or pursuant to Benefit Plans provided
         the existence of such liabilities does not violate any representation
         or warranty in Section 4.12(c) which is attributable to facts existing,
         or actions taken (or omissions occurring) prior to the Closing, which
         liability arises under ERISA due to (i) the acts or omissions of NPL
         with respect to the Benefit Plans or (ii) the acts or omissions of
         fiduciaries of the Benefit Plans to whom NPL is obligated to provide
         indemnification by contract or otherwise.

                  (d) The aggregate liability of NPL Shareholders, if any, shall
         be limited to a maximum of one million two hundred thousand dollars
         ($1,200,000) and the NPL Shareholders shall only be liable to the
         extent that indemnifiable amounts hereunder exceed, in the aggregate,
         two hundred forty thousand dollars ($240,000). The NPL Shareholders'
         share of any liability shall be in proportion to their respective NPL
         stock ownership at Closing and may be paid either in cash or in
         Southwest stock valued at the same price as at the Closing.

                  13.2 Southwest's Indemnification. Southwest shall indemnify
NPL and NPL Shareholders from and against all claims, losses, damages, costs,
assessments, judgments, awards, liabilities and expenses (including, without
limitation, costs and expenses of litigation and, to the extent permitted by
law, reasonable attorneys' fees)


                                       60
   65
incurred by NPL or NPL Shareholders by reason of the untruthfulness or
inaccuracy of any of Southwest's representations or warranties or the breach of
any Southwest obligations contained in this Agreement.

                  13.3     Claims for Indemnity.

                  (a) Making of Claims for Indemnity. A claim for indemnity
         under this Agreement may be made by the indemnified party any time
         prior to one year after the Closing. Except for a claim for fraud, a
         claim for indemnity under this Agreement shall be the exclusive remedy
         of any indemnified party against any indemnifying party with respect to
         any claims, losses, damages, costs, assessments, judgments, awards,
         liabilities and expenses which arise out of or in any way relate to any
         act or omission in connection with the negotiation, execution, delivery
         or performance of this Agreement. Notwithstanding the foregoing, an
         indemnified party may pursue any available legal proceedings to enforce
         the obligation of an indemnifying party if such indemnifying party
         refuses or fails to perform such obligation, but the recovery in any
         such proceedings shall be limited to amounts which the indemnified
         party would have been entitled to be paid by the indemnifying party
         hereunder, together with the costs and expenses of such enforcement
         proceeding as provided in Section 14.10 hereof.

                  In the event that any such claim is made within such
         prescribed period, the indemnity relating to such claim shall survive
         until such claim is resolved. Claims not made within the applicable
         period shall not be indemnified hereunder. Each written notice of a
         claim for indemnity shall set forth in reasonable detail the basis


                                       61
   66
         upon which such claim for indemnity is made.

                  (b) Conduct of Lawsuits. In the event that any person or
         entity not a party to this Agreement shall make any demand or claim or
         file or threaten to file any lawsuit, which demand, claim or lawsuit
         may result in any loss, cost or expense subject to indemnification
         under this Agreement, then the indemnified party shall provide written
         notice of such demand, claim or lawsuit to the indemnifying party as
         soon as is reasonably practicable but, in any event, within five (5)
         days after discovery or receipt of such demand, claim or lawsuit (but
         failure to notify within such time period shall not rescind or revoke
         the indemnifying party's obligation to indemnify but shall only reduce
         the amount of the indemnification to the extent that the indemnifying
         party is damaged by such delay), and the indemnifying party shall have
         the option, at its cost and expense, to defend itself or to retain
         counsel for the indemnified party to defend any such demand, claim or
         lawsuit. In the event that the indemnifying party shall fail to respond
         to the indemnified party within five days after receipt of such written
         notice of any such demand, claim or lawsuit, then the indemnified party
         may retain counsel and conduct the defense of such demand, claim or
         lawsuit as it may in its reasonable discretion deem proper, at the
         reasonable cost and expense of the indemnifying party, subject,
         however, to the indemnifying party's right to intervene in such defense
         at any time upon the giving of reasonable notice. The indemnified party
         shall use its best reasonable efforts to cooperate and assist the
         indemnifying party in defending any such demand, claim or lawsuit,
         which shall include, but not be limited to, the pursuit of all
         cross-


                                       62
   67
         claims and counterclaims associated therewith. In effecting the
         settlement of any such demand, claim or lawsuit, an indemnified party
         shall act in good faith, shall consult with the indemnifying party, and
         shall enter into only such settlement as the indemnifying party shall
         approve, which approval will not be unreasonably withheld and will be
         implied if the indemnifying party does not respond within 15 days of
         its receipt of the notice of such settlement offer. 

         14. Miscellaneous.

                  14.1 Non-Compete Agreements. Noel T. Coon agrees that he will
not, directly or indirectly, engage in competition with NPL or the Surviving
Corporation in the states where either is now operating or has current plans to
operate at the time of Closing for a period of four years following the Closing.
William L. Johnson and Michael J. Kemper each agrees that he will not, directly
or indirectly, engage in competition with NPL or the Surviving Corporation in
the states where Surviving Corporation is operating at the time William L.
Johnson or Michael J. Kemper, respectively, leaves the employment of the
Surviving Corporation (except for the state of Michigan as to Mr. Johnson) for a
period of two years following termination of his employment. The foregoing
provisions shall apply to competition in any manner whatsoever including but not
limited to, as an employee, independent contractor, consultant, owner, manager,
shareholder, director, officer, principal, agent or trustee of or for any person
or entity engaged in a business the same as or similar to that of NPL or
Surviving Corporation or for their own account. Each NPL Shareholder further
agrees that the foregoing non-competition provisions are reasonable as applied
to him, would not impose any undue hardship on him if in force and is no wider


                                       63
   68
in scope than necessary to afford reasonable protection to Southwest and
Surviving Corporation. This section becomes effective upon the Closing and at
that time supersedes the non-compete agreements contained in the existing
Johnson and Kemper employment agreements.

                  14.2 NPL Promissory Notes to Noel T. Coon. The outstanding
promissory notes in the approximate amount of $3.9 million from NPL to Noel T.
Coon may be paid off in full by NPL prior to the Closing provided that NPL has
adequate cash and credit to continue its operations in its usual and customary
manner.

                  14.3 Survival. Subject to Section 13.3, the respective
representations and warranties, covenants and agreements set forth in this
Agreement and all Disclosure Schedules shall survive the Closing.

                  14.4 Notices. All notices, requests, claims, demands or other
communica tions hereunder shall be in writing and shall be given (and shall be
deemed to have been duly received if so given) by delivery, by registered or
certified mail (return receipt requested) or by cable, telecopier, or telex to
the respective parties as follows:

                  (a)      If to Southwest, to:

                           Michael O. Maffie
                           President and Chief Executive Officer
                           Southwest Gas Corporation
                           5241 Spring Mountain Road
                           P.O. Box 98510
                           Las Vegas, Nevada 89193-8510
                           Telephone: (702)876-7250
                           Telecopier: (702)876-7037


                                       64
   69
                           With a copy to:

                           Thomas J. Trimble
                           Senior Vice President/General Counsel
                             and Corporate Secretary
                           Southwest Gas Corporation
                           5241 Spring Mountain Road
                           P.O. Box 98510
                           Las Vegas, Nevada 89193-8510
                           Telephone: (702)876-7189
                           Telecopier: (702)876-7037

                  (b)      If to NPL, to:

                           Noel T. Coon
                           10840 East Candlewood Drive
                           Scottsdale, Arizona 85255
                           Telephone: (602)585-9803

                           With a copy to:

                           William L. Johnson
                           12500 Summit Street
                           Kansas City, Missouri 64145
                           Telephone: (816)942-6069

or such other address as shall be furnished in writing by any party to the
others in accordance herewith, except that notices of change of address will
only be effective upon receipt.

                  14.5 Parties in Interest. This Agreement shall be binding upon
and shall inure to the benefit of the parties hereto and their respective
successors and assigns; provided, however, that neither this Agreement nor any
of the rights, interests or obligations hereunder shall be assigned by any party
hereto without the prior written consent of the other parties. Nothing in this
Agreement is intended to confer, expressly


                                       65
   70
or by implication, upon any other person any rights or remedies under or by
reason of this Agreement.

                  14.6 Entire Agreement. This Agreement, including the documents
and other writings referred to herein or delivered pursuant hereto, contains the
entire agreement and understanding of the parties with respect to its subject
matter. There are no restrictions, agreements, promises, warranties, covenants
or undertakings between the parties other than those expressly set forth herein
or therein. This Agreement supersedes all prior agreements and understandings
between the parties, both written and oral, with respect to its subject matter.

                   14.7 Counterparts. This Agreement may be executed in one or
more counterparts all of which shall be considered one and the same agreement
and each of which shall be deemed an original.

                   14.8 Governing Law. This Agreement, in all respects,
including all matters of construction, validity and performance, is governed by
the internal laws of the state of Nevada applicable to contracts executed and
delivered in Nevada by citizens of such state, to be performed wholly within
such state without giving effect to the principles of conflicts of laws thereof.
This Agreement is being delivered in Las Vegas, Nevada.

                   14.9 Headings. The Section headings contained in this
Agreement are for reference purposes only and shall not affect in any way the
meaning or interpretation of this Agreement.

                   14.10 Enforcement Costs. In the event of litigation or other
proceeding to enforce this Agreement, the prevailing party or parties shall be
entitled to recover


                                       66
   71
reasonable costs and attorneys' fees to be set by the court and not by the jury.

                   IN WITNESS WHEREOF, the parties hereto have executed this
Agreement this 13th day of November, 1995.

NORTHERN PIPELINE                         NPL SHAREHOLDERS
CONSTRUCTION CO.,
a Minnesota corporation

                                          /s/ NOEL T. COON
                                          ----------------------------------
                                          Noel T. Coon

By:    /s/ WILLIAM L. JOHNSON
     ------------------------------
       William L. Johnson
                                          /s/ ALEXA S. HIGASHI
                                          ----------------------------------
Title: Chief Executive Officer            Alexa S. Higashi, his wife

Attest:  /s/ ROBERT DIGAN                 /s/ WILLIAM L. JOHNSON
        ---------------------------       ----------------------------------
         Robert Digan                     William L. Johnson

Title: Assistant Secretary
                                          /s/ JUDY JOHNSON
                                          ----------------------------------
                                          Judy Johnson, his wife

                                          /s/ MICHAEL J. KEMPER
                                          ----------------------------------
                                          Michael J. Kemper

                                          /s/ FRANCES KEMPER
                                          ----------------------------------
                                          Frances Kemper, his wife

                                          SOUTHWEST GAS CORPORATION, a
                                          California corporation

                                          By     /s/ MICHAEL O. MAFFIE
                                             -------------------------------
                                                   Michael O. Maffie

                                          Title:   President and Chief Executive
                                                      Officer


                                       67
   72
                                    ATTEST:     /s/ THOMAS J. TRIMBLE
                                             ---------------------------------
                                                  Thomas J. Trimble

                                    TITLE: Senior Vice President/General
                                           Counsel and Corporate Secretary

                                    SOUTHWEST GAS CORPORATION
                                      OF ARIZONA, a Nevada corporation

                                    By:      /s/ MICHAEL O. MAFFIE
                                         -------------------------------------
                                                Michael O. Maffie

                                    TITLE: President and Chief Executive
                                           Officer

                                    ATTEST:     /s/ THOMAS J. TRIMBLE
                                             ---------------------------------
                                                  Thomas J. Trimble

                                    TITLE: Senior Vice President/General
                                              Counsel and Corporate Secretary


                                       68
   73
                                    EXHIBIT B

Ladies and Gentlemen:

         This firm has acted as counsel for Northern Pipeline Construction Co.,
a Minnesota corporation ("NPL"), and NPL Shareholders in connection with the
proposed acquisition of NPL by Southwest Gas Corporation, a California
corporation ("Southwest"), pursuant to the Merger Agreement between Southwest
and Southwest Gas Corporation of Arizona, a Nevada corporation (the "Merger
Sub"), and NPL and NPL Shareholders dated as of November 13, 1995 (the
"Agreement"). This opinion is delivered to you pursuant to Section 8.2 of the
Agreement. Unless otherwise defined herein, all capitalized terms used in this
opinion shall have the meanings attributed to them in the Agreement.

         In our capacity as counsel for NPL and NPL Shareholders and for
purposes of this opinion, we have made those examinations and investigations of
the local and factual matters we deemed advisable, and have examined the
originals, or copies identified to our satisfaction as being true copies of the
originals, of the certificates, documents, corporate records, and other
instruments which we, in our judgment, have considered necessary or appropriate
to enable us to render the opinion expressed below. For these purposes, we have,
without independent investigation or confirmation, relied upon certificates
provided by public officials and officers of NPL as to certain factual matters
including those certificates described below. In the course of our examinations
and investigations we have assumed the genuineness of all signatures on original
documents, and the due execution and delivery of all documents requiring due
execution and delivery for the effectiveness thereof.

         Based upon and subject to the foregoing and in reliance thereon, and
subject to the assumptions, exceptions and qualifications set forth herein, it
is our opinion that:

                  1. NPL is a corporation duly organized, validly existing and
         in good standing under the laws of Minnesota, with the corporate powers
         and authority to own, lease and operate all of its properties and
         assets and to carry on its business as presently being conducted;

                  2. NPL is duly licensed and qualified to do business as a
         foreign corporation and is in good standing in Arizona, Colorado,
         Illinois, Kansas, Missouri, Montana, Nebraska, Nevada, New Jersey,
         Pennsylvania, Utah, Washington, and Wisconsin and in any other


   74


To _________________
Date
Page 2

         jurisdiction in which, to the best of our knowledge after due inquiry,
         the nature of the business conducted by it makes such licensing or
         qualification necessary and where the failure to be so qualified would,
         individually or in the aggregate, have a Material Adverse Effect;

                  3. NPL has the corporate Power and authority to consummate the
         transactions contemplated by the Agreement, and NPL has duly taken all
         requisite corporate action to authorize, execute and deliver the
         Agreement and perform the transactions contemplated by the Agreement.
         The Agreement and appropriate Exhibits thereto have been duly executed
         and delivered by NPL and constitute valid, binding and enforceable
         obligations of NPL and NPL Shareholders;

                  4. The authorized capital stock of NPL consists solely of
         15,000 shares of Common Stock, par value $10.00 per share, of which
         ________ shares are issued and outstanding. All shares of the
         outstanding capital stock of NPL have been duly authorized and validly
         issued and are fully paid and nonassessable. After due inquiry, other
         than as described in the Agreement, we are not aware of any
         reservations for the issuance of NPL Common Stock or any outstanding
         subscriptions, options, warrants, calls, commitments, or agreements of
         any character calling for the transfer, purchase, or issuance of any
         shares of its Common Stock or any securities representing the right to
         purchase or otherwise receive any shares of its Common Stock or any
         securities convertible into or representing the right to purchase or
         subscribe to any such shares;

                  5. On the Closing Date and prior to the consummation of the
         transactions contemplated by the Agreement, the NPL Shareholders were
         the record owners of all of the issued and outstanding shares of NPL's
         Common Stock;

                  6. Neither the execution and delivery by NPL of the Agreement,
         nor the consummation of the transactions contemplated thereby, will (i)
         constitute a breach or violation of the Articles of Incorporation or
         Bylaws of NPL, (ii) violate any statute, code, ordinance, rule,
         regulation, judgment, order, writ, decree or injunction, after due
         inquiry, known to us to be applicable to NPL, or any of its respective
         properties or assets, or (iii) to the best of our knowledge after due
         inquiry, violate, conflict with, result in a breach of any provisions
         of,


   75
To _________________
Date
Page 3

         constitute a default (or an event which, with notice or lapse of time,
         or both, would constitute a default) under, result in the termination
         of, accelerate the performance required by, or result in the creation
         of any lien, security interest, charge or other encumbrance upon any of
         the properties or assets of NPL, under any of the terms, conditions, or
         provisions of any note, bond, mortgage indenture, deed of trust,
         license, lease, agreement or other instrument or obligation to which
         NPL is a party, or by which it or any of its properties or assets may
         be bound or affected, except where such violations, conflicts,
         breaches, defaults, termination, accelerations and encumbrances would
         not have a Material Adverse Effect, nor prevent the consummation of the
         transactions contemplated by the Agreement.

                  7. There are no pending or, to the best of our knowledge after
         due inquiry, threatened actions, suits, claims inquiries, proceedings
         or investigations involving NPL before any court, commission, bureau,
         regulatory, administrative or governmental agency, arbitrator, body or
         authority that could have a Material Adverse Effect or which affect
         NPL's obligations under or purport to affect the legality, validity or
         enforceability of the Agreement or the transactions contemplated
         thereby;

                  8. Assuming due authorization of the Merger by all necessary
         corporate proceedings on the part of Southwest and Merger Sub and that
         Southwest and Merger Sub have taken all action required to be taken by
         them prior to the Closing Date, in accordance with the provision of the
         Agreement, the Merger will be validly consummated in accordance with
         the Agreement and Minnesota law, and each outstanding share of NPL
         Common Stock, including shares issued upon exercise of options to
         purchase NPL Common Stock which will have been exercised, prior to the
         Closing will be converted as provided in the Agreement; and

                  9. All governmental consents and approvals required to be
         obtained by NPL in order to permit the consummation by it of the
         Agreement and transactions contemplated thereby have been obtained, and
         all filings required to be made by NPL in order to permit such
         consummation have been made.

         We express no opinion with respect to the laws of any jurisdiction,
other than the United States and Arizona, the general corporate law of the State
of 


   76
To _________________
Date
Page 4


Minnesota and with respect to the opinion set forth in paragraph 2 only the laws
of the States of Colorado, Illinois, Kansas, Missouri, Montana, Nebraska,
Nevada, New Jersey, Pennsylvania, Utah, Washington and Wisconsin. The Agreement
is governed by Nevada law and we have assumed with your consent that, to the
extent applicable to our opinions set forth herein, Nevada law is the same as
Arizona law, to the extent Nevada law is controlling.

         With respect to our opinion relating to the enforceability of any
agreement or contract, our opinion is qualified in that enforceability may be
limited by the application of bankruptcy, insolvency, reorganization,
moratorium, or similar laws relating to or affecting creditors' rights generally
(including, without limitation, fraudulent conveyance laws), and by general
principles of equity, including, without limitation, concepts of materiality,
reasonableness, good faith and fair dealing and the possible unavailability of
specific performance or injunctive relief, regardless of whether considered in a
proceeding in equity or at law.

         This opinion is being delivered to you for your sole use and benefit in
connection with the acquisition of NPL by Southwest pursuant to the Agreement
and may not be relied upon by, nor may copies be delivered to, any other person
without our prior written consent. This opinion is given as of the date hereof
and we assume no obligation to advise you of changes that may hereinafter be
brought to our attention.

                                                     Very truly yours,