<PAGE>   1
                                                                   EXHIBIT 10.25


================================================================================

                            STOCK PURCHASE AGREEMENT

                          DATED AS OF FEBRUARY 2, 2001


                                 BY AND BETWEEN


                                  PROBEX CORP.

                                       AND

                       UNITED INFRASTRUCTURE COMPANY, LLC

================================================================================


<PAGE>   2


                                TABLE OF CONTENTS

<TABLE>
<CAPTION>
SECTION                                                                               PAGE

<S>      <C>      <C>                                                                 <C>
1.       PURCHASE AND SALE OF COMMON STOCK...............................................2
         (a)      Purchase of Common Stock...............................................2
         (b)      Closing Dates..........................................................2
         (c)      Price Per Share Calculation............................................2
         (d)      Form of Payment........................................................3

2.       REPRESENTATIONS AND WARRANTIES OF INVESTOR......................................3
         (a)      Investment Purpose.....................................................3
         (b)      Accredited Investor Status.............................................3
         (c)      Reliance on Exemptions.................................................3
         (d)      Information............................................................3
         (e)      Governmental Review....................................................4
         (f)      Transfer or Resale.....................................................4
         (g)      Legends................................................................4
         (h)      Authorization; Enforcement.............................................5

3.       REPRESENTATIONS AND WARRANTIES OF THE COMPANY...................................5
         (a)      Organization and Qualification.........................................5
         (b)      Authorization; Enforcement.............................................5
         (c)      Capitalization.........................................................6
         (d)      Acknowledgement of Debt Obligation.....................................7
         (e)      Issuance of the Shares.................................................7
         (f)      No Conflicts...........................................................7
         (g)      SEC Documents; Financial Statements....................................8
         (h)      Undisclosed Liabilities................................................8
         (i)      Absence of Certain Changes.............................................9
         (j)      Absence of Litigation..................................................9
         (k)      Suppliers and Customers...............................................10
         (l)      Intellectual Property.................................................10
         (m)      No Materially Adverse Contracts.......................................11
         (n)      Tax Status............................................................11
         (o)      Certain Transactions..................................................11
         (p)      Disclosure............................................................12
         (q)      Acknowledgment Regarding Investor's Purchase of the Shares............12
         (r)      No Integrated Offering................................................12
         (s)      No Brokers............................................................12
         (t)      Permits; Compliance...................................................12
         (u)      Environmental Matters.................................................13
         (v)      Title to Property.....................................................13
         (w)      Insurance.............................................................13
         (x)      Internal Accounting Controls..........................................14
         (y)      Labor Relations.......................................................14
         (z)      Foreign Corrupt Practices.............................................14
         (aa)     Benefit Plans.........................................................14
         (bb)     No Manipulation of Stock..............................................14
         (cc)     Accountants...........................................................15
         (dd)     Contracts.............................................................15
         (ee)     Solvency..............................................................15
         (ff)     Investment Company....................................................15
         (gg)     Proprietary Information and Inventions Agreements.....................15
</TABLE>


                                      -i-
<PAGE>   3


                                TABLE OF CONTENTS
                                  (CONTINUED)

<TABLE>
<CAPTION>
SECTION                                                                                    PAGE

<S>      <C>      <C>                                                                      <C>
4.       COVENANTS OF THE COMPANY AND INVESTOR...............................................15
         (a)      Commercially Reasonable Efforts............................................15
         (b)      Form D; Blue Sky Laws......................................................15
         (c)      Reporting Status...........................................................15
         (d)      Use of Proceeds............................................................16
         (e)      Financial Information......................................................16
         (f)      Listing of the Shares......................................................16
         (g)      Corporate Existence........................................................16
         (h)      Business...................................................................16

5.       CONDITIONS TO THE COMPANY'S OBLIGATION AT CLOSING - SECOND TRANCHE INVESTMENT.......16
         (a)      Payment of Purchase Price..................................................16
         (b)      Execution of Strategic Alliance Agreement..................................17
         (c)      Accuracy of Representations................................................17
         (d)      Investor's Performance.....................................................17
         (e)      No Litigation..............................................................17

6.       CONDITIONS TO INVESTOR'S OBLIGATION AT CLOSING - SECOND TRANCHE INVESTMENT..........17
         (a)      Delivery of Strategic Alliance Agreement...................................17
         (b)      Delivery of Common Stock Certificates......................................17
         (c)      Delivery of Compliance Certificate.........................................17
         (d)      Accuracy of Representations................................................17
         (e)      The Company's Performance..................................................18
         (f)      No Proceedings.............................................................18
         (g)      No Claim Regarding Stock Ownership or Sale Proceeds........................18
         (h)      No Prohibition.............................................................18
         (i)      No Litigation..............................................................18
         (j)      Common Stock Trading.......................................................18
         (k)      Opinion of Counsel.........................................................18
         (l)      Blue Sky Law Filings.......................................................18
         (m)      Certificate of the Company's Transfer Agent................................19
         (n)      Other Documents............................................................19

7.       CONDITIONS TO COMPANY'S OBLIGATION AT CLOSING - THIRD TRANCHE INVESTMENT............19
         (a)      Payment of Purchase Price..................................................19
         (b)      Execution of EPC Agreement.................................................19
         (c)      Accuracy of Representations................................................19
         (d)      Investor's Performance.....................................................19
         (e)      No Litigation..............................................................19

8.       CONDITIONS TO investor's OBLIGATION at closing - third tranche investment...........19
         (a)      Execution of EPC Agreement.................................................20
         (b)      Delivery of Common Stock Certificates......................................20
         (c)      Delivery of Compliance Certificate.........................................20
         (d)      Satisfaction with Terms and Conditions of Wellsville Project Debt..........20
         (e)      Accuracy of Representations................................................20
</TABLE>


                                      -ii-
<PAGE>   4


                                TABLE OF CONTENTS
                                  (CONTINUED)
<TABLE>
<CAPTION>
SECTION                                                                                    PAGE

<S>      <C>      <C>                                                                      <C>
         (f)      The Company's Performance..................................................20
         (g)      No Proceedings.............................................................20
         (h)      No Claim Regarding Stock Ownership or Sale Proceeds........................20
         (i)      No Prohibition.............................................................21
         (j)      No Litigation..............................................................21
         (k)      Common Stock Trading.......................................................21
         (l)      Opinion of Counsel.........................................................21
         (m)      Blue Sky Law Filings.......................................................21
         (n)      Certificate of the Company's Transfer Agent................................21
         (o)      Other Documents............................................................21

9.       FIRST TRANCHE ADJUSTMENT OBLIGATION OF THE COMPANY..................................21

10.      SURVIVAL OF REPRESENTATIONS, WARRANTIES AND COVENANTS; INDEMNIFICATION..............22
         (a)      Survival of Representations, Warranties and Covenants......................22
         (b)      Indemnification............................................................22
         (c)      Claims for Indemnification; Defense of Indemnified Claims..................22

11.      GENERAL PROVISIONS..................................................................23
         (a)      Governing Law..............................................................23
         (b)      Counterparts; Signatures by Facsimile......................................23
         (c)      Headings...................................................................23
         (d)      Severability...............................................................23
         (e)      Specific Performance.......................................................23
         (f)      Entire Agreement; Amendments...............................................23
         (g)      Notices....................................................................24
         (h)      Successors and Assigns.....................................................24
         (i)      Third Party Beneficiaries..................................................25
         (j)      Publicity..................................................................25
         (k)      Further Assurances.........................................................25
         (l)      Limited Recourse...........................................................25
         (m)      Waiver.....................................................................25
         (n)      No Strict Construction.....................................................25

EXHIBIT A         Form of Registration and Investor's Rights Agreement........................a
EXHIBIT B         Form of Additional Right to Purchase Agreement..............................b
EXHIBIT C         Disclosure Schedule.........................................................c
</TABLE>


                                     -iii-
<PAGE>   5


                            STOCK PURCHASE AGREEMENT

         THIS STOCK PURCHASE AGREEMENT (this "Agreement"), is made as of
February 2, 2001, by and between Probex Corp., a Delaware corporation, with
headquarters located at 13355 Noel Road, Suite 1200, Dallas, Texas 75240 (the
"Company"), and United Infrastructure Company, LLC, a Delaware limited liability
company ("Investor").

         WHEREAS, the Company is an energy technology company commercializing
its proprietary re-processing technology (ProTerra(TM)), intended for the
purification, recycling, and upgrading of used lubricating oils.

         WHEREAS, the Company is engaged in the early stages of developing its
first domestic production facility, to be located in Wellsville, Ohio, which is
intended to convert waste lubricating oils into premium base oils, fuel oil and
asphalt flux or modifier (the "Wellsville Project").

         WHEREAS, Investor is an affiliate of Bechtel Enterprises Holdings,
Inc., a Delaware corporation ("BEn"), which is an affiliate of Bechtel
Corporation, a Nevada corporation ("Bechtel"). Bechtel is an investor in the
Company and holds restricted shares of the Company's common stock.

         WHEREAS, the Company has entered into negotiations with Bechtel
respecting a strategic alliance under which the Company would engage Bechtel for
the engineering, procurement and construction of the Company's plant facilities,
including the Wellsville Project.

         WHEREAS, pursuant to that certain Stock Purchase Agreement, dated as of
October 12, 2000, Investor purchased Five Hundred Thousand (500,000) shares of
the Company's common stock, par value $.001 per share (the "Common Stock") with
a purchase price per share of Two Dollars ($2.00) (the "First Tranche Price Per
Share"), for an aggregate purchase price of One Million Dollars ($1,000,000.00)
(the "First Tranche Investment').

         WHEREAS, upon the terms and conditions set forth herein, the Company
has authorized the issuance and sale of, and Investor wishes to purchase,
additional shares of Common Stock, in two additional tranches, as set forth
below.

         WHEREAS, the Company and Investor are executing and delivering this
Agreement in reliance upon the exemption from securities registration afforded
by Rule 506 under Regulation D ("Regulation D") as promulgated by the United
States Securities and Exchange Commission (the "SEC") under the Securities Act
of 1933, as amended (the "Securities Act").

         WHEREAS, contemporaneous with the execution and delivery of this
Agreement, the parties hereto are executing and delivering (a) a Registration
and Investor's Rights Agreement, in the form attached hereto as Exhibit A (the
"Registration Rights Agreement"), pursuant to which the Company has agreed to
provide certain registration rights under the Securities Act and the rules and
regulations promulgated thereunder, and applicable state securities laws; and
(b) an Additional Right to Purchase Agreement, in the form attached hereto as
Exhibit B (the "Additional Right to Purchase Agreement"), pursuant to which the
Company has agreed to provide Investor with the opportunity to make additional
equity investments in the Company in certain circumstances.


                                      -1-
<PAGE>   6


         NOW THEREFORE, the Company and Investor hereby agree as follows:

         1. PURCHASE AND SALE OF COMMON STOCK.

                  (a) Purchase of Common Stock. Subject to the terms, conditions
and obligations of this Agreement, on the Closing Dates (as defined below), the
Company shall issue and sell to Investor and Investor agrees to purchase from
the Company, certain shares of Common Stock as described below in two separate
tranches (the "Shares"), for an aggregate purchase price of One Million Dollars
($1,000,000.00) (the "Second Tranche Investment") and Three Million Dollars
($3,000,00.00) (the "Third Tranche Investment"), respectively (the "Purchase
Price"), with a purchase price per Share and the resulting number of Shares to
be issued to be determined in accordance with the formulae set forth in clause
(c) of this Section 1 (the "Price Per Share").

                  (b) Closing Dates. The completion of the purchase and sale of
the Shares shall occur as follows:

                           (i) Second Tranche Closing Date. The closing of the
Second Tranche Investment shall occur two business days following the
satisfaction or waiver of each of the conditions set forth in Section 5 and
Section 6 hereof (the "Second Tranche Closing Date").

                           (ii) Third Tranche Closing Date. The closing of the
Third Tranche Investment shall occur two business days following the
satisfaction or waiver of each of the conditions set forth in Section 7 and
Section 8 hereof (the "Third Tranche Closing Date"). For purposes of this
Agreement, each of the Second Tranche Closing Date and the Third Tranche Closing
Date may be referred to separately as the "Closing Date," or collectively as the
"Closing Dates."

                  (c) Price Per Share Calculation.

                           (i) Second Tranche Price Per Share.

                                    (A) The Price Per Share, subject to
adjustment, for the Second Tranche Investment shall be the lesser of (1) ninety
percent (90%) of the closing sale price per share of Common Stock quoted on the
American Stock Exchange (the "AMEX") on the date hereof, (2) the trailing
average of the closing sale price per share of Common Stock quoted on the AMEX
for the thirty (30) business days immediately preceding the Second Tranche
Closing Date, and (3) the average price per share paid in connection with any
private placement offering of the Common Stock in the period between the date
hereof and the Second Tranche Closing Date (the "Second Tranche Price Per
Share").

                                    (B) Adjustment. If, within forty-five (45)
days following the Second Tranche Closing Date, the Company shall issue shares
of Common Stock pursuant to a public offering or a private placement and the
issuance price per share of such Common Stock is less than the Second Tranche
Price Per Share, then the number of Shares issued to Investor hereunder shall be
adjusted and additional Shares shall be issued so that the aggregate number of
Shares issued to Investor with respect to the Second Tranche Investment shall be
equal to the dollar amount of the Second Tranche Investment divided by the
lowest price per share paid by any other investor in the public offering or
private placement (rounded up or down, as applicable, to the nearest whole
Share) during such 45-day period. The Company shall, within five (5) business
days after the occurrence of any event requiring such adjustment, notify
Investor of the adjustment and cause such additional Shares to be issued to
Investor.


                                       -2-
<PAGE>   7


                           (ii) Third Tranche Price Per Share.

                                    (A) The Price Per Share, subject to
adjustment, for the Third Tranche Investment shall be the lesser of (1) ninety
percent (90%) of the closing sale price per share of Common Stock quoted on the
AMEX on the date hereof, (2) the trailing average of the closing sale price per
share of Common Stock quoted on the AMEX for the thirty (30) business days
immediately preceding the Third Tranche Closing Date, and (3) the average price
per share paid in connection with any private placement offering of the Common
Stock between the date hereof and the Third Tranche Closing Date (the "Third
Tranche Price Per Share").

                                    (B) Adjustment. If, at any time prior to the
Third Tranche Closing Date, events affecting the capital markets cause the
trading price per share of the Common Stock to drop 25% or more below either the
First Tranche Price Per Share or the Second Tranche Price Per Share, then, prior
to the Third Tranche Closing Date, the parties hereto shall agree upon an
equitable adjustment in the parameters used to determine the Third Tranche Price
Per Share (by way of example and without limitation, a market price discount
factor) to reflect the perceived higher market risk.

                  (d) Form of Payment. Upon each Closing Date, (i) Investor
shall pay the Purchase Price for the Shares to be issued and sold to it at that
Closing by wire transfer of immediately available funds to the Company, in
accordance with the Company's written wiring instructions, against delivery of
duly executed certificates representing the number of Shares which Investor is
purchasing, and (ii) the Company shall deliver such certificates duly executed
on behalf of the Company to Investor or, if so designated by Investor, in the
name of a nominee designated by Investor, against delivery of the Second Tranche
Investment or Third Tranche Investment, as the case may be.

         2. REPRESENTATIONS AND WARRANTIES OF INVESTOR. Investor represents and
warrants to the Company that:

                  (a) Investment Purpose. Investor is purchasing the Shares for
its own account for investment only and not with a present view towards the
public sale or distribution thereof, except pursuant to sales registered or
exempted from registration under the Securities Act.

                  (b) Accredited Investor Status. Investor is an "accredited
investor" as that term is defined in Rule 501(a) of Regulation D promulgated
under the Securities Act.

                  (c) Reliance on Exemptions. Investor understands that the
Shares are being offered and sold to it in reliance upon specific exemptions
from the registration requirements of United States federal and state securities
laws, and that the Company is relying upon the truth and accuracy of, and
Investor's compliance with, the representations, warranties, agreements,
acknowledgments and understandings of Investor set forth herein in order to
determine the availability of such exemptions and the eligibility of Investor to
acquire the Shares.

                  (d) Information. Investor and its advisors have been furnished
with all materials relating to the business, finances and operations of the
Company and materials relating to the offer and sale of the Common Stock which
have been requested by Investor or its advisors. Investor and its advisors have
been afforded the opportunity to ask questions of the Company. Neither such
inquiries nor any other due diligence investigation conducted by Investor or any
of its advisors or representatives shall modify, amend or affect Investor's
right to


                                      -3-
<PAGE>   8


rely on the Company's representations and warranties contained in Section 3
hereof. Investor understands that its investment in the Shares involves a
significant degree of risk.

                  (e) Governmental Review. Investor understands that no United
States federal or state agency or any other government or governmental agency
has passed upon or made any recommendation or endorsement of the Shares.

                  (f) Transfer or Resale. Investor understands that:

                           (i) except as provided in the Registration Rights
Agreement, the Shares have not been and are not being registered under the
Securities Act or any applicable state securities laws, and may not be
transferred unless (a) subsequently included in an effective registration
statement thereunder, (b) Investor shall have delivered to the Company an
opinion of counsel (which opinion shall be reasonably acceptable to the Company)
to the effect that the Shares to be sold or transferred may be sold or
transferred pursuant to an exemption from such registration, (c) sold or
transferred to an "affiliate" (as defined in Rule 144, promulgated under the
Securities Act (or a successor rule) ("Rule 144")), or (d) sold pursuant to Rule
144;

                           (ii) any sale of such Shares made in reliance on Rule
144 may be made only in accordance with the terms of said Rule and further, if
said Rule is not applicable, any resale of such Shares under circumstances in
which the seller (or the person through whom the sale is made) may be deemed to
be an underwriter (as that term is defined in the Securities Act) may require
compliance with some other exemption under the Securities Act or the rules and
regulations of the SEC thereunder; and

                           (iii) neither the Company nor any other person is
under any obligation to register such Shares under the Securities Act or any
state securities laws or to comply with the terms and conditions of any
exemption thereunder (in each case, other than pursuant to the Registration
Rights Agreement). Notwithstanding the foregoing or anything else contained
herein to the contrary, the Shares may be pledged as collateral in connection
with a bona fide margin account or other lending arrangement.

                  (g) Legends. Investor understands that until such time as the
Shares have been registered under the Securities Act as contemplated by the
Registration Rights Agreement, the Shares shall bear a restrictive legend in
substantially the following form (and a stop-transfer order may be placed
against transfer of the certificates for such Shares):

                  "The securities represented by this certificate have not been
                  registered under the Securities Act of 1933, as amended. The
                  securities have been acquired for investment and may not be
                  sold, hypothecated, transferred or assigned in the absence of
                  an effective registration statement for the securities under
                  said Act, or an opinion of counsel, in form, substance and
                  scope reasonably acceptable to Probex Corp., that registration
                  is not required under said Act or unless sold pursuant to Rule
                  144 under said Act. Notwithstanding the foregoing, this
                  security may be pledged in connection with a bona fide margin
                  account."

         The legend set forth above shall be removed and the Company shall issue
a certificate without such legend to the holder of any Shares upon which it is
stamped, if, unless otherwise required by applicable state securities laws, (i)
such Shares are registered for sale under an


                                      -4-
<PAGE>   9


effective registration statement filed under the Securities Act and disposed of
in a bona fide sale, (ii) such holder provides the Company with an opinion of
counsel, in form, substance and scope reasonably acceptable to the Company, to
the effect that a public sale or transfer of such Shares may be made without
registration under the Securities Act and such sale or transfer is effected, or
(iii) such holder provides the Company with reasonable assurances that such
Shares can be sold pursuant to Rule 144 under the Securities Act (or a successor
rule thereto) without any restriction as to the number of Shares acquired as of
a particular date that can then be immediately sold. Investor agrees to sell all
Shares, including those represented by a certificate(s) from which the legend
has been removed, in compliance with applicable prospectus delivery
requirements, if any (including any amendment to any of the foregoing).

                  (h) Authorization; Enforcement. This Agreement, the
Registration Rights Agreement and the Additional Right to Purchase Agreement
have been duly and validly authorized, executed and delivered on behalf of
Investor and are valid and binding agreements of Investor, enforceable in
accordance with their terms.

         3. REPRESENTATIONS AND WARRANTIES OF THE COMPANY. Except as (1)
otherwise described in the Company's Schedule 14A, Form 10-SB, current reports
on Form 8-K and regular reports on Form 10-QSB and Form 10-KSB as filed
(including any amendment(s) to any of the foregoing) by the Company with the SEC
(the "SEC Documents"), (2) otherwise described in any of the Company's press
releases since December 31, 1999 (including the documents incorporated by
reference therein, the "Company Information"), or (3) disclosed in the
disclosure schedule to this Agreement (the "Disclosure Schedule"), attached
hereto as Exhibit C, which qualifies the following representations and
warranties in their entirety and which shall be updated and delivered to
Investor at least ten (10) business days prior to any Closing Date, the Company
hereby represents and warrants to and covenants with Investor, as follows:

                  (a) Organization and Qualification. The Company and each
Subsidiary (as defined below), is a corporation duly organized, validly existing
and in good standing under the laws of the jurisdiction in which it is
incorporated, with full power and authority (corporate and other) to own, lease,
use and operate its properties and to carry on its business as described in the
SEC Documents as and where now owned, leased, used, operated and conducted. The
Company does not have an equity investment in any other person other than the
Subsidiaries listed in Schedule 3(a) of the Disclosure Schedule. The Company and
each Subsidiary is duly qualified as a foreign corporation to do business and is
in good standing in every jurisdiction in which its ownership or use of property
or the nature of the business conducted by it makes such qualification
necessary, except where the failure to be so qualified or in good standing would
not have a Material Adverse Effect. For purposes of this Agreement, "Material
Adverse Effect" means any material adverse effect on the business, operations,
assets, financial condition or prospects of the Company or any Subsidiary, taken
as a whole, or on the transactions contemplated hereby or by the agreements or
instruments to be entered into in connection herewith. "Subsidiary" (or
collectively, "Subsidiaries") means any corporation or other organization,
whether incorporated or unincorporated, in which the Company owns, directly or
indirectly, any equity or other ownership interest.

                  (b) Authorization; Enforcement. (i) The Company has all
requisite corporate power to enter into and perform this Agreement, the
Registration Rights Agreement and the Additional Right to Purchase Agreement,
and to consummate the transactions contemplated hereby and thereby and to issue
the Shares in accordance with the terms hereof, (ii) the execution and delivery
of this Agreement, the Registration Rights Agreement and the Additional


                                      -5-
<PAGE>   10


Right to Purchase Agreement by the Company and the consummation by it of the
transactions contemplated hereby and thereby have been duly authorized by the
Company's Board of Directors, and no further consent or authorization of the
Company, its Board of Directors, or its stockholders is required, (iii) this
Agreement, the Registration Rights Agreement and the Additional Right to
Purchase Agreement have been duly executed and delivered, and each such document
is a legal, valid and binding obligation of the Company enforceable against the
Company, in accordance with their terms.

                  (c) Capitalization. As of January 12, 2001, the authorized
capital stock of the Company consists of:

                           (i) One Hundred Million (100,000,000) shares of
Common Stock, of which twenty six million two hundred twenty six thousand five
hundred thirty four (26,226,534) shares were outstanding, all of which are duly
authorized, validly issued, fully paid and nonassessable.

                           (ii) Ten Million (10,000,000) shares of Preferred
Stock, $.001 par value (the "Preferred Stock"), of which five hundred fifty
thousand (550,000) shares have been designated as Series A 10% Cumulative
Convertible Preferred Stock, and five hundred thirty five thousand (535,000) of
which are outstanding and are duly authorized, validly issued, fully paid and
nonassessable.

                           (iii) Since January 12, 2001, there has been (x) no
material increase in the number of shares of Common Stock outstanding (except
for shares issued upon exercise of options and warrants to purchase shares of
Common Stock outstanding on the date hereof), and (y) no issuance of shares of
Preferred Stock of the Company. Schedule 3(c)(iii) of the Disclosure Schedule
discloses all outstanding options or warrants for the purchase of, or other
rights to purchase or subscribe for, or securities convertible into or
exchangeable for, or otherwise entitling the holder to acquire, Common Stock or
other capital stock of the Company, or any contracts or commitments to issue or
sell Common Stock or other capital stock of the Company or any such options,
warrants, rights or other securities; and from the date hereof until each
Closing Date, as appropriate, there has been no material change in the amount or
terms of any of the foregoing except for (i) the grant of options to purchase
shares of Common Stock pursuant to the Company's stock option plans in effect on
the date of this Agreement or as such stock option plans are contemplated to be
amended as of the date of this Agreement, (ii) the conversion of convertible
securities outstanding on the date hereof, and (iii) the issuance of any shares
of Common Stock or securities convertible into shares of Common Stock for which
the Investor has received any applicable adjustment in accordance with Section
1(c)(i)(B) above.

                           (iv) The Company has duly reserved from its
authorized and unissued shares of Common Stock the full number of shares
required for (a) all options, warrants, convertible securities, exchangeable
securities, and other rights to acquire shares of Common Stock which are
outstanding, and (b) all shares of Common Stock and options and other rights to
acquire shares of Common Stock which may be issued or granted under the stock
option and similar plans which have been adopted by the Company or any
Subsidiary. Each outstanding class or series of securities for which any
antidilution adjustment will occur is identified on Schedule 3(c)(iv) of the
Disclosure Schedule attached hereto, together with the amount of such
antidilution adjustment for each such class or series. The outstanding shares of
Common Stock and outstanding options, warrants and other securities entitling
the holders to purchase or otherwise acquire Common Stock have been duly
authorized and validly issued. None of the outstanding shares of Common Stock or
options, warrants and other such securities has been issued in violation of the
preemptive rights of any securityholder of the Company. The offers and


                                      -6-
<PAGE>   11


sales of the outstanding shares of Common Stock and options, warrants and other
rights to acquire Common Stock were at all relevant times either registered
under the Securities Act and applicable state securities laws or exempt from
such requirements. Except as set forth on Schedule 3(c)(iv), there are no
stockholders agreements, voting agreements or other similar agreements with
respect to the Common Stock to which the Company is a party. Except as set forth
on Schedule 3(c)(iv), no holder of any of the Company's securities has any
rights, "demand," "piggy-back" or otherwise, to have such securities registered
by reason of the Company's intention to file, filing or effectiveness of the
registration statement on Form SB-2, Form S-1 or Form S-3, if applicable,
registering the Shares for resale (the "Registration Statement").

                           (v) The Company is furnishing to Investor true and
correct copies of the Company's Certificate of Incorporation, as in effect on
the date hereof ("Certificate of Incorporation"), the Company's By-laws, as in
effect on the date hereof (the "By-laws"), and the forms of all securities
convertible into or exercisable for Common Stock of the Company and the material
rights of the holders thereof in respect thereto.

                  (d) Intentionally Omitted

                  (e) Issuance of the Shares. The Shares to be issued pursuant
to this Agreement will be duly authorized, validly issued, fully paid and
non-assessable, free and clear of all liens and encumbrances, and will not
subject the holder thereof to personal liability by reason of being such holder.
There are no preemptive or similar rights of any stockholder of the Company or
any other person to acquire any of the Shares. The Common Stock is listed for
trading on the AMEX and (1) the Company and the Common Stock meet the criteria
for continued listing and trading on the AMEX; (2) the Company has not been
notified since January 1, 1996 by either the National Association of Securities
Dealers, Inc. (the "NASD") or the AMEX, of any failure or potential failure to
meet the criteria for continued listing and trading on the AMEX; (3) no
suspension of trading in the Common Stock is in effect; and (4) the Company does
not reasonably anticipate that the Common Stock will be delisted by the AMEX in
the foreseeable future. The Company knows of no reason that the Common Stock
will not be eligible for continued listing on the AMEX. The Shares to be issued
pursuant to this Agreement shall have been approved for listing on the AMEX (or
any other exchange or quotation system on which the Common Stock of the Company
is then listed) promptly after issuance.

                  (f) No Conflicts. Except as set forth in Schedule 3(f) of the
Disclosure Schedule, the execution, delivery and performance of this Agreement,
the Registration Rights Agreement and the Additional Right to Purchase Agreement
by the Company and the consummation by the Company of the transactions
contemplated hereby and thereby will not (i) conflict with or result in a
violation of any provision of the Certificate of Incorporation or the By-laws,
or (ii) violate or conflict with, or result in a breach of any provision of, or
constitute a default (or an event which with notice or lapse of time or both
could become a default) under, or give to others any rights of termination,
amendment, acceleration or cancellation of, any agreement, indenture or
instrument to which the Company or any Subsidiary is a party, or result in a
violation of any law, rule, regulation, order, judgment or decree (including
federal and state securities laws and regulations) applicable to the Company or
any Subsidiary or by which any property or asset of the Company or any
Subsidiary is bound or affected, except for such conflicts, defaults,
terminations, amendments, accelerations, cancellations and violations as would
not, individually or in the aggregate, have a Material Adverse Effect. Neither
the Company nor any Subsidiary is in violation of its certificate of
incorporation, by-laws or other organizational documents and neither the Company
nor any Subsidiary is in default, and no event has occurred which with notice or
lapse of time or both could put the Company or any Subsidiary in default, under,
and


                                      -7-
<PAGE>   12


neither the Company nor any Subsidiary has taken any action or failed to take an
action that would give to others any rights of termination, amendment,
acceleration or cancellation of, any agreement, indenture instrument to which
the Company or any Subsidiary is a party or by which any property or assets of
the Company or any Subsidiary is bound or affected, except for possible defaults
as would not, individually or in the aggregate, have a Material Adverse Effect.
Except as specifically contemplated by this Agreement and as required under the
Securities Act and any applicable state securities laws, the Company is not
required to obtain any consent, authorization or order of, or make any filing or
registration with, any court or governmental agency or any regulatory or
regulatory agency in order for it to execute, deliver or perform any of its
obligations under this Agreement, the Registration Rights Agreement or the
Additional Right to Purchase Agreement in accordance with the terms hereof or
thereof. All consents, authorizations, orders, filings and registrations which
the Company is required to obtain pursuant to the preceding sentence have been
obtained or effected on or prior to the date hereof. The Company and each
Subsidiary are unaware of any facts or circumstances which might give rise to
any of the foregoing.

                  (g) SEC Documents; Financial Statements.

                           (i) The Company has timely filed all reports,
schedules, forms, statements and other documents required to be filed by it with
the SEC pursuant to the reporting requirements of the Securities Exchange Act of
1934, as amended (the "Exchange Act") and any other material reports or
documents required to be filed with the SEC. The Company has delivered to
Investor, true and complete copies of the SEC Documents. As of their respective
dates, the SEC Documents complied in all material respects with the requirements
of the Exchange Act and the rules and regulations of the SEC promulgated
thereunder applicable to the SEC Documents, and none of the SEC Documents, at
the time they were filed with the SEC, contained any untrue statement of a
material fact or omitted to state a material fact required to be stated therein,
or necessary in order to make the statements therein, in light of the
circumstances under which they were made, not misleading.

                           (ii) As of their respective dates, the financial
statements of the Company included in the SEC Documents complied as to form in
all material respects with applicable accounting requirements and the published
rules and regulations of the SEC with respect thereto. Such financial statements
have been prepared in accordance with United States generally accepted
accounting principles ("GAAP"), consistently applied, during the periods
involved (except (1) as may be otherwise indicated in such financial statements
or the notes thereto, or (2) in the case of unaudited interim statements, to the
extent they may not include footnotes or may be condensed or summary statements)
and fairly present in all material respects, the consolidated financial position
of the Company and its consolidated Subsidiaries, as of the dates thereof and
the consolidated results of their operations and cash flows for the periods then
ended (subject, in the case of unaudited statements, to normal year-end audit
adjustments). The unaudited pro forma combined financial statements filed with
the SEC comply in all material respects with the requirements of Article 11 of
Regulation S-X under the Securities Act.

                  (h) Undisclosed Liabilities. Except as set forth in the
financial statements of the Company included in the SEC Documents and Schedule
3(h) of the Disclosure Schedule, the Company has no liabilities, contingent or
otherwise, other than (i) liabilities incurred in the ordinary course of
business subsequent to the date of the most recent financial statements of the
Company included in the SEC Documents, and (ii) obligations under contracts and
commitments incurred in the ordinary course of business and not required under
GAAP to be


                                      -8-
<PAGE>   13


reflected in such financial statements, which, individually or in the aggregate,
are not material to the financial condition or operating results of the Company.

                  (i) Absence of Certain Changes. Since the date of the most
recent financial statements of the Company included in the SEC Documents, and
except as referenced in Schedule 3(h) above, there has not been, respecting the
Company or any Subsidiary:

                           (i) any change in the assets, liabilities, financial
condition or operating results of the Company from that reflected in the
financial statements, except changes in the ordinary course of business that
have not been, in the aggregate, materially adverse;

                           (ii) any damage, destruction or loss, whether or not
covered by insurance, materially and adversely affecting the assets, properties,
financial condition, operating results, prospects or business of the Company (as
such business is presently conducted and as it is proposed to be conducted);

                           (iii) any waiver by the Company of a valuable right
or of a material debt owed to it;

                           (iv) any satisfaction or discharge of any lien, claim
or encumbrance or payment of any obligation by the Company, except in the
ordinary course of business and that is not material to the assets, properties,
financial condition, operating results or business of the Company (as such
business is presently conducted and as it is proposed to be conducted);

                           (v) any material change or amendment to a material
contract or arrangement by which the Company or any of its assets or properties
is bound or subject;

                           (vi) any material change in any compensation
arrangement or agreement with any employee;

                           (vii) any sale, assignment or transfer of any
material patents, trademarks, copyrights, trade secrets or other intangible
assets;

                           (viii) any resignation or termination of employment
of any key officer of the Company; and the Company, to the best of its
knowledge, does not know of the impending resignation or termination of
employment of any such officer;

                           (ix) receipt of notice that there has been a loss of,
or material order cancellation by, any major customer of the Company;

                           (x) any mortgage, pledge, transfer of a security
interest in, or lien, created by the Company, with respect to any of its
material properties or assets, except liens for taxes not yet due or payable; or

                           (xi) to the best of the Company's knowledge, any
other event or condition of any character that might materially and adversely
affect the assets, properties, financial condition, operating results or
business of the Company (as such business is presently conducted and as it is
proposed to be conducted).

                  (j) Absence of Litigation. Except as disclosed in the SEC
Documents, there is no action, suit, proceeding, inquiry or investigation before
or by any court, public board or body or governmental agency pending or
threatened against the Company or any Subsidiary, in any


                                      -9-
<PAGE>   14


such case wherein an unfavorable decision, ruling or finding is reasonably
likely and would reasonably be expected to have a Material Adverse Effect.
Except as set forth on Schedule 3(j) of the Disclosure Schedule, the Company
does not have pending before the SEC, any request for confidential treatment of
information and to the best of the Company's knowledge, no such request will be
made by the Company prior to the time the Registration Statement relating to the
Shares, which is contemplated by Section 2 of the Registration Rights Agreement,
is first ordered effective by the SEC and there is not pending or contemplated,
and there has been no investigation by the SEC involving the Company, any
Subsidiary, or any current or former director or officer of the Company or any
Subsidiary. The Company and its Subsidiaries are unaware of any facts or
circumstances which might give rise to any of the foregoing.

                  (k) Suppliers and Customers.

                           (i) Each of the Company and each Subsidiary has
adequate sources of supply for its business as currently conducted and as
proposed to be conducted. Each has good relationships with all of its material
sources of supply of goods and services and each does not anticipate any
material problem with any such material sources of supply.

                           (ii) Neither the Company nor any Subsidiary has any
knowledge that the customer base of the Company and/or any Subsidiary might
materially decrease.

                  (l) Intellectual Property.

                           (i) Except as set forth on Schedule 3(l)(i) of the
Disclosure Schedule, the Company and each Subsidiary has ownership or license or
legal right to use all patent, copyright, trade secret, trademark, customer
lists, designs, manufacturing or other processes, computer software, systems,
data compilation, research results or other proprietary rights used in the
business of the Company and each Subsidiary and material to the Company and each
Subsidiary (collectively, "Intellectual Property") other than Intellectual
Property generally available on commercial terms from other sources. Except as
set forth on Schedule 3(l)(i), all of such patents, trademarks and registered
copyrights have been duly registered in, filed in or issued by the United States
Patent and Trademark Office, the United States Register of Copyrights or the
corresponding offices of other jurisdictions and have been maintained and
renewed in accordance with all applicable provisions of law and administrative
regulations in the United States and all such jurisdictions.

                           (ii) All material licenses or other material
agreements under which (x) the Company and each Subsidiary is granted rights in
Intellectual Property, other than Intellectual Property generally available on
commercial terms from other sources, and (y) the Company has granted rights to
others in Intellectual Property owned or licensed by the Company, are in full
force and effect and there is no material default by the Company and each
Subsidiary thereto.

                           (iii) The Company and each Subsidiary believes it has
taken all steps required in accordance with sound business practice and business
judgment to establish and preserve its ownership of all material copyright,
trade secret and other proprietary rights with respect to its products and
technology.

                           (iv) The present business, activities and products of
the Company and each Subsidiary do not infringe any intellectual property of any
other person, except where such infringement would not have a Material Adverse
Effect. Except as described in the SEC Documents, no proceeding charging the
Company or any Subsidiary with infringement of


                                      -10-
<PAGE>   15


any adversely held Intellectual Property has been filed. There exists no
unexpired patent or patent application which includes claims that would be
infringed by or otherwise have a Material Adverse Effect. Neither the Company
nor any Subsidiary is making unauthorized use of any confidential information or
trade secrets of any person. Neither the Company nor any of its employees have
any agreements or arrangements with any persons other than the Company related
to confidential information or trade secrets of such persons or restricting any
such employee's engagement in business activities of any nature. The activities
of the Company or any of its employees on behalf of the Company do not violate
any such agreements or arrangements known to the Company which any such
employees have with other persons, if any.

                           (v) No proceedings have been instituted or are
pending which challenge the rights of the Company with respect to the Company's
right to the use of the Intellectual Property. Further, no proceedings have been
instituted or are pending which challenge the rights of any Subsidiary of the
Company with respect to such Subsidiary's right to the use of the Intellectual
Property. The Company and each Subsidiary have the right to use, free and clear
of material claims or rights of other persons, all of their respective customer
lists, designs, computer software, systems, data compilations, and other
information that are required for its products or its business as presently
conducted.

                  (m) No Materially Adverse Contracts. To the knowledge of the
Company, neither the Company nor any Subsidiary is subject to any charter,
corporate or other legal restriction, or any judgment, decree, order, rule or
regulation which in the judgment of the Company's officers, has or is expected
in the future to have a Material Adverse Effect. Neither the Company nor any
Subsidiary is a party to any contract or agreement which, in the judgment of the
Company's officers, has or is expected to have a Material Adverse Effect.

                  (n) Tax Status. The Company and each Subsidiary has made or
filed all federal and state income and all other tax returns, reports and
declarations required by any jurisdiction to which it is subject (unless and
only to the extent that the Company and each Subsidiary has set aside on its
books provisions reasonably adequate for the payment of all unpaid and
unreported taxes) and has paid all taxes and other governmental assessments and
charges that are material in amount, shown or determined to be due on such
returns, reports and declarations, except those being contested in good faith
and has set aside on its books provisions reasonably adequate for the payment of
all taxes for periods subsequent to the periods to which such returns, reports
or declarations apply. There are no unpaid taxes in any material amount claimed
to be due by the taxing authority of any jurisdiction, and the officers of the
Company or any Subsidiary know of no basis for any such claim.

                  (o) Certain Transactions. Except as set forth in the SEC
Documents and except for arm's length transactions pursuant to which the Company
or any Subsidiary makes payments in the ordinary course of business upon terms
no less favorable than the Company or any Subsidiary could obtain from third
parties and other than the grant of stock options disclosed in the SEC
Documents, none of the officers, directors, or employees of the Company is
presently a party to any transaction with the Company or any Subsidiary (other
than for services as employees, officers and directors), including any contract,
agreement or other arrangement providing for the furnishing of services to or
by, providing for rental of real or personal property to or from, or otherwise
requiring payments to or from any officer, director or such employee or any
corporation, partnership, trust or other entity in which any officer, director,
or any such employee has a substantial interest or is an officer, director,
trustee or partner.


                                      -11-
<PAGE>   16


                  (p) Disclosure. No representation or warranty contained in
this Agreement, and no statement contained in the SEC Documents, Company
Information or in any certificate, list or other writing furnished to Investor
pursuant to any provision of this Agreement contains any untrue statement of a
material fact or omits to state a material fact necessary in order to make the
statements herein or therein, in light of the circumstances under which they
were made, not misleading. No event or circumstance has occurred or exists with
respect to the Company or any Subsidiary or its or their business, properties,
prospects, operations or financial conditions, which, under applicable law, rule
or regulation, requires public disclosure or announcement by the Company but
which has not been so publicly announced or disclosed (assuming for this
purposes that the Company's reports filed under the Exchange Act are being
incorporated into an effective registration statement filed by the Company under
the Securities Act).

                  (q) Acknowledgment Regarding Investor's Purchase of the
Shares. The Company acknowledges and agrees that Investor is acting solely in
the capacity of arm's length purchaser with respect to this Agreement and the
transactions contemplated hereby. The Company further acknowledges that Investor
is not acting as a financial advisor or fiduciary of the Company (or in any
similar capacity) with respect to this Agreement, and the transactions
contemplated hereby and any advice given by Investor or any of its
representatives or agents in connection with this Agreement and the transactions
contemplated hereby is merely incidental to Investor's purchase of the Shares.
The Company further represents to Investor that the Company's decision to enter
into this Agreement has been based solely on the independent evaluation of the
Company and its representatives.

                  (r) No Integrated Offering. Neither the Company, nor any of
its affiliates, nor any person acting on its or their behalf, has directly or
indirectly made any offers or sales in any security or solicited any offers to
buy any security under circumstances that would require registration under the
Securities Act of the issuance of the Shares to Investor. The issuance of the
Shares to Investor will not require stockholder approval under the rules of the
AMEX nor will the Shares be integrated with any other issuance of the Company's
securities (past, current or future) which requires stockholder approval under
the rules of the AMEX.

                  (s) No Brokers. The Company has taken no action which would
give rise to any claim by any person for brokerage commissions, finder's fees or
similar payments relating to this Agreement or the transactions contemplated
hereby, except for dealings with persons whose commissions and fees will be paid
for by the Company.

                  (t) Permits; Compliance. The Company and each Subsidiary is in
possession of all franchises, grants, authorizations, licenses, permits,
easements, variances, exemptions, consents, certificates, approvals and orders
necessary to own, lease and operate its properties and to carry on its business
as it is now being conducted (collectively, the "Company Permits"), and there is
no action pending or, to the knowledge of the Company, threatened regarding
suspension or cancellation of any of the Company Permits. Neither the Company
nor any Subsidiary is in conflict with, or in default or violation of, any of
the Company Permits, except for any such conflicts, defaults or violations
which, individually or in the aggregate, would not reasonably be expected to
have a Material Adverse Effect. Since the date of the most recent financial
statements of the Company included in the SEC Documents, neither the Company nor
any Subsidiary has received any notification with respect to possible conflicts,
defaults or violations of applicable laws, except for notices relating to
possible conflicts, defaults or violations, which conflicts, defaults or
violations would not have a Material Adverse Effect.


                                      -12-
<PAGE>   17


                  (u) Environmental Matters.

                           (i) Except as set forth in the SEC Documents or
Schedule 3(u)(i) of the Disclosure Schedule, there are, with respect to the
Company or any Subsidiary or any predecessor of the Company, no past or present
violations of Environmental Laws (as defined below), releases of any material
into the environment, actions, activities, circumstances, conditions, events,
incidents, or contractual obligations which may give rise to any common law
environmental liability or any liability under the Comprehensive Environmental
Response, Compensation and Liability Act of 1980 or similar federal, state,
local or foreign laws, and neither the Company nor any Subsidiary has received
any notice with respect to any of the foregoing, nor is any action pending or,
to the Company's knowledge, threatened in connection with any of the foregoing.
The term "Environmental Laws" means all federal, state, local or foreign laws
relating to pollution or protection of human health or the environment
(including, without limitation, ambient air, surface water, groundwater, land
surface or subsurface strata), including, without limitation, laws relating to
emissions, discharges, releases or threatened releases of chemicals, pollutants
contaminants, or toxic or hazardous substances or wastes (collectively,
"Hazardous Materials") into the environment, or otherwise relating to the
manufacture, processing, distribution, use, treatment, storage, disposal,
transport or handling of Hazardous Materials, as well as all authorizations,
codes, decrees, demands or demand letters, injunctions, judgments, licenses,
notices or notice letters, orders, permits, plans or regulations issued,
entered, promulgated or approved thereunder.

                           (ii) Other than those that are or were stored, used
or disposed of in compliance with applicable law, no Hazardous Materials are
contained on or about any real property currently owned, leased or used by the
Company or any Subsidiary, including without limitation, the Wellsville Project
site, and no Hazardous Materials were released on or about any real property
previously owned, leased or used by the Company or any Subsidiary during the
period the property was owned, leased or used by the Company or any Subsidiary,
except in the normal course of the Company's or any Subsidiary's business.

                           (iii) Except as set forth in the SEC Documents or
Schedule 3(u)(i) of the Disclosure Schedule, there are no underground storage
tanks on or under any real property owned, leased or used by the Company or any
Subsidiary, including without limitation, the Wellsville Project site, that are
not in compliance with applicable law.

                  (v) Title to Property. Except as set forth in Schedule 3(h) of
the Disclosure Schedule, the Company and each Subsidiary have good and
marketable title in fee simple to all real property and good and marketable
title to all personal property owned by them which is material to the business
of the Company and its Subsidiaries, in each case free and clear of all liens,
encumbrances and defects such as would not have a Material Adverse Effect. Any
real property and facilities held under lease by the Company and its
Subsidiaries are held by them under valid, subsisting and enforceable leases
with such exceptions as would not have a Material Adverse Effect. Neither the
Company nor any Subsidiary has received notice of any material violation of any
applicable law, ordinance, regulation, order or requirement relating to its
owned or leased properties.

                  (w) Insurance. The Company and each Subsidiary are insured by
insurers of recognized financial responsibility against such losses and risks
and in such amounts as management of the Company believes to be prudent and
customary in the businesses in which the Company and its Subsidiaries are
engaged. Neither the Company nor any Subsidiary has reason to believe that it
will not be able to renew its existing insurance coverage as and when


                                      -13-
<PAGE>   18


such coverage expires or to obtain similar coverage from similar insurers as may
be necessary to continue its business at a cost that would not have a Material
Adverse Effect.

                  (x) Internal Accounting Controls. The Company and each
Subsidiary maintain a system of internal accounting controls sufficient to
provide reasonable assurance that (i) transactions are executed in accordance
with management's general or specific authorizations, (ii) transactions are
recorded as necessary to permit preparation of financial statements in
conformity with GAAP and to maintain asset accountability, (iii) access to
assets is permitted only in accordance with management's general or specific
authorization, and (iv) the recorded accountability for assets is compared with
the existing assets at reasonable intervals and appropriate action is taken with
respect to any differences.

                  (y) Labor Relations. No material labor problem exists or is
imminent with respect to any of the employees of the Company or any Subsidiary.
Neither the Company nor any Subsidiary has any knowledge as to any intentions of
any key employee to leave the employ of the Company or any Subsidiary.

                  (z) Foreign Corrupt Practices. Neither the Company, nor any
Subsidiary, nor any director, officer, agent, employee or other person acting on
behalf of the Company or any Subsidiary has, in the course of his or her actions
for, or on behalf of, the Company or any Subsidiary, used any corporate funds
for any unlawful contribution, gift, entertainment or other unlawful expenses
relating to political activity; made any direct or indirect unlawful payment to
any foreign or domestic government official or employee from corporate funds;
violated or is in violation of any provision of the United States Foreign
Corrupt Practices Act of 1977, as amended; or made any bribe, rebate, payoff,
influence payment, kickback or other unlawful payment to any foreign or domestic
government official or employee.

                  (aa) Benefit Plans. Each Benefit Plan (as defined below) which
is intended to be qualified under Section 401(a) of the Internal Revenue Code of
1986, as amended (the "Code"), has either received a determination letter from
the Internal Revenue Service to the effect that such Plan (as defined below) is
so qualified or is a standardized prototype plan which relies on an opinion
letter issued to the sponsor of such prototype. No Benefit Plan (i) is a
"defined benefit plan" within the meaning of Section 414(j) of the Code, (ii) is
a multiemployer plan within the meaning of Section 3(37) of ERISA, or (iii)
provided health benefit or life insurance coverage beyond the termination of an
employee's employment, except as required by Part 6 of Subtitle B of Title I of
ERISA or Section 4980B of the Code. For purposes hereof: "Benefit Plan" means
each Plan pursuant to which the Company or any Subsidiary maintains, contributes
to, or has any liability in respect of current or former employees, agents,
directors, or independent contractors or any beneficiaries or dependents of any
such current or former employees agents, directors, or independent contractors;
"ERISA" means the Employee Retirement Income Security Act of 1974, as amended,
and the rules and regulations promulgated thereunder; and "Plan" means any
bonus, incentive compensation, deferred compensation, pension, profit sharing,
retirement, stock purchase, stock option, stock ownership, stock appreciation
rights, phantom stock, leave of absence, layoff, vacation, day or dependent
care, legal services, cafeteria, life, health, accident, disability, workmen's
compensation or other insurance, severance, separation or other employee benefit
plan, practice, policy or arrangement of any kind, whether written or oral, or
whether for the benefit of a single individual or more than one individual
including, but not limited to, any "employee benefit plan" within the meaning of
Section 3(3) of ERISA.

                  (bb) No Manipulation of Stock. The Company has not taken and
will not, in violation of applicable law take, any action designed to or that
might reasonably be expected to


                                      -14-
<PAGE>   19


cause or result in unlawful manipulation of the price of the Common Stock to
facilitate the sale or resale of the Shares.

                  (cc) Accountants. The accountants who expressed their opinion
with respect to the SEC Documents are independent accountants as required by the
Securities Act and the rules and regulations promulgated thereunder.

                  (dd) Contracts. The contracts described in the SEC Documents
or incorporated by reference therein, which have not expired per their terms,
are in full force and effect on the date hereof, and neither the Company nor, to
the Company's knowledge, any other party to such contracts is in breach of or
default under any of such contracts which would have a Material Adverse Effect.

                  (ee) Solvency. The Company (both before and after giving
effect to the transactions contemplated by this Agreement) is solvent (i.e., its
assets have a fair market value in excess of the amount required to pay its
probable liabilities on its existing debts as they become absolute and matured)
and currently the Company has no information that would lead it to reasonably
conclude that the Company would not have, nor does it intend to take any action
that would impair, its ability to pay its debts from time to time incurred in
connection therewith as such debts mature. The Company did not receive a
qualified opinion from its auditors with respect to its most recent fiscal year
end and does not anticipate or know of any basis upon which its auditors might
issue a qualified opinion in respect of its current fiscal year.

                  (ff) Investment Company. The Company is not, and after giving
effect to the offer and sale of the Shares and the application of the proceeds
thereof will not be, an "investment company" or an "affiliated person" of, or
"promoter" or "principal underwriter" for an investment company, within the
meaning of the Investment Company Act of 1940, as amended.

                  (gg) Proprietary Information and Inventions Agreements. Each
officer, technical and engineering employee and each consultant of the Company
has executed a Confidentiality and Invention Assignment Agreement. The Company
is not aware that any of the Company's employees, officers or consultants are in
violation of the terms thereof.

         4. COVENANTS OF THE COMPANY AND INVESTOR.

                  (a) Commercially Reasonable Efforts. The parties shall use
their commercially reasonable efforts to satisfy timely, applicable conditions
to closing described in Sections 5, 6, 7 and 8 hereof.

                  (b) Form D; Blue Sky Laws. The Company agrees to file a Form D
with respect to each issuance of Shares as required under Regulation D and to
provide a copy thereof to Investor promptly after such filing. The Company
shall, on or before each Closing Date, take such action as the Company shall
reasonably determine is necessary to qualify the Shares for sale to Investor at
the Closing pursuant to this Agreement under applicable securities or "blue sky"
laws of the states of the United States (or to obtain an exemption from such
qualification).

                  (c) Reporting Status. The Common Stock is registered under
Section 12(b) of the Exchange Act. So long as Investor or any of its affiliates
beneficially owns any of the Shares, and until such Shares may be sold under
Rule 144(k), the Company shall timely file all reports required to be filed with
the SEC pursuant to the Exchange Act, and the Company shall


                                      -15-
<PAGE>   20


not terminate its status as an issuer required to file reports under the
Exchange Act, even if the Exchange Act or the rules and regulations thereunder
would permit such termination.

                  (d) Use of Proceeds. The Company will use the proceeds
realized from the sale of the Shares to fund acquisitions, future development
opportunities and for working capital purposes. None of such proceeds will be
used, directly or indirectly to make any loan to or investment in any other
person.

                  (e) Financial Information. The Company agrees to send the
following reports to Investor, to the attention of the Chief Operating Officer:
(i) within ten (10) days after the filing with the SEC, a copy of its Annual
Report on Form 10-K or Form 10-KSB, its Quarterly Reports on Form 10-Q or Form
10-QSB and any Current Reports on Form 8-K; (ii) within one (1) day after
release, copies of all press releases issued by the Company or any Subsidiary;
and (iii) contemporaneously with the making available or giving to the
stockholders of the Company, copies of any notices or other information the
Company makes available or gives to its stockholders.

                  (f) Listing of the Shares. The Company shall promptly secure
the listing of the Shares upon each national securities exchange or automated
quotation system, if any, upon which shares of Common Stock are then listed
(subject to official notice of issuance) and shall maintain, so long as any
other shares of Common Stock shall be so listed, such listing of all Shares. The
Company will obtain and maintain the listing and trading of its Common Stock on
the AMEX and will comply in all respects with the Company's reporting, filing
and other obligations under the bylaws or rules of the NASD and such exchanges,
as applicable. The Company shall promptly provide to Investor copies of any
notices it receives from the AMEX or NASD and any other exchanges or quotation
systems on which the Common Stock is then listed or quoted regarding the
continued eligibility of the Common Stock for listing or quotation on such
exchanges and quotation systems.

                  (g) Corporate Existence. So long as Investor or any of its
affiliates beneficially owns any Shares, the Company shall maintain its
corporate existence and shall not sell all or substantially all of the Company's
assets, except in the event of a merger or consolidation or sale of all or
substantially all of the Company's assets, where the surviving or successor
entity in such transaction (i) assumes the Company's obligations hereunder and
under the agreements and instruments entered into in connection herewith, and
(ii) is a publicly traded corporation whose Common Stock is listed for trading
on the Nasdaq National Market, Nasdaq SmallCap, the New York Stock Exchange or
the AMEX.

                  (h) Business. The Company shall continue in the core lines of
business contemplated in the Company's SEC Documents until two (2) years from
the Closing Date last in time.

         5. CONDITIONS TO THE COMPANY'S OBLIGATION AT CLOSING - SECOND TRANCHE
INVESTMENT. The obligation of the Company hereunder to issue and sell the Shares
to Investor and to take the other actions required to be taken by the Company
with respect to the Second Tranche Investment, is subject to the satisfaction on
or before the Second Tranche Closing Date, of each of the following conditions,
provided that these conditions are for the Company's sole benefit and may be
waived by the Company at any time in its sole discretion:

                  (a) Payment of Purchase Price. Investor shall have delivered
the Second Tranche Investment in accordance with Sections 1(a) and 1(d) hereof.


                                      -16-
<PAGE>   21


                  (b) Execution of Strategic Alliance Agreement. The Company and
Bechtel shall have executed, and Bechtel shall have delivered, a strategic
alliance agreement setting forth the principal terms whereby Bechtel will
provide engineering, procurement and construction services with respect to the
Wellsville Project and other mutually agreed upon development sites (the
"Strategic Alliance Agreement").

                  (c) Accuracy of Representations. All of Investor's
representations and warranties set forth herein (considered collectively), and
each of these representations and warranties (considered individually), must
have been accurate in all material respects as of the date of this Agreement and
must be accurate in all material respects as of the Second Tranche Closing Date,
as if made on such date.

                  (d) Investor's Performance.

                           (i) All of the covenants and obligations that
Investor is required to perform or to comply with pursuant to this Agreement at
or prior to the Second Tranche Closing Date (considered collectively), and each
of these covenants and obligations (considered individually), must have been
performed and complied with in all material respects.

                           (ii) Investor must have delivered each of the
documents required to be delivered by Investor pursuant this Agreement.

                  (e) No Litigation. No litigation, statute, rule, regulation,
executive order, decree, ruling or injunction shall have been enacted, entered,
promulgated or endorsed by or in any court or governmental authority of
competent jurisdiction or any self-regulatory organization having authority over
the matters contemplated hereby which prohibits the consummation of any of the
transactions contemplated by this Agreement.

         6. CONDITIONS TO INVESTOR'S OBLIGATION AT CLOSING - SECOND TRANCHE
INVESTMENT. The obligation of Investor hereunder to purchase the Shares and to
take the other actions required to be taken by Investor with respect to the
Second Tranche Investment, is subject to the satisfaction on or before the
Second Tranche Closing Date, of each of the following conditions, provided that
these conditions are for Investor's sole benefit and may be waived by Investor
at any time in its sole discretion:

                  (a) Delivery of Strategic Alliance Agreement. The Company and
Bechtel shall have executed, and the Company shall have delivered, the Strategic
Alliance Agreement.

                  (b) Delivery of Common Stock Certificates. The Company shall
have delivered to Investor duly executed certificate(s) (in such denominations
as Investor shall reasonably request) representing the Shares to be issued in
accordance with Section 1 hereof.

                  (c) Delivery of Compliance Certificate. The Company shall have
delivered to Investor as of the Second Tranche Closing Date, a certificate
signed on its behalf by its Chief Executive Officer, Chief Financial Officer or
other authorized person, stating that there has been no material adverse change
in the business, affairs, prospects, operations, properties, assets or condition
of the Company not previously disclosed to the Investor in writing.

                  (d) Accuracy of Representations. All of the Company's
representations and warranties set forth herein (considered collectively), and
each of these representations and warranties (considered individually), must
have been accurate in all material respects as of the


                                      -17-
<PAGE>   22


date of this Agreement, and must be accurate in all material respects as of the
Second Tranche Closing Date, as if made on such date.

                  (e) The Company's Performance.

                           (i) All of the covenants and obligations that the
Company is required to perform or to comply with pursuant to this Agreement on
or prior to the Second Tranche Closing Date (considered collectively), and each
of these covenants and obligations (considered individually), must have been
duly performed and complied with in all material respects.

                           (ii) Each document required to be delivered by the
Company pursuant to this Agreement must have been delivered, and each of the
other covenants and obligations contained herein and therein must have been
performed and complied with by the Company in all material respects.

                  (f) No Proceedings. Since the date of this Agreement, there
must not have been commenced or threatened against Investor, or against any
person affiliated with Investor, any proceeding (i) involving any challenge to,
or seeking damages or other relief in connection with, any of the contemplated
transactions, or (ii) that may have the effect of preventing, delaying, making
illegal, or otherwise interfering with any of the contemplated transactions.

                  (g) No Claim Regarding Stock Ownership or Sale Proceeds. There
must not have been made or threatened by any person any claim asserting that
such person (i) is the holder or the beneficial owner of, or has the right to
acquire or to obtain beneficial ownership of, any stock of, or any other voting,
equity, or ownership interest in, the Company or any Subsidiary other than as
set forth in Schedule 3(c)(iii), or (ii) is entitled to all or any portion of
the Purchase Price payable for the Shares .

                  (h) No Prohibition. Neither the consummation nor the
performance of any of the contemplated transactions will, directly or indirectly
(with or without notice or lapse of time), materially contravene, or conflict
with, or result in a material violation of, or cause Investor or any person
affiliated with Investor to suffer any material adverse consequence under, (i)
any applicable legal requirement or order, or (ii) any legal requirement or
order that has been published, introduced, or otherwise proposed by or before
any governmental body.

                  (i) No Litigation. No litigation, statute, rule, regulation,
executive order, decree, ruling or injunction shall have been enacted, entered,
promulgated or endorsed by or in any court or governmental authority of
competent jurisdiction or any self-regulatory organization having authority over
the matters contemplated hereby which prohibits the consummation of any of the
transactions contemplated by this Agreement.

                  (j) Common Stock Trading. Trading in the Common Stock on the
AMEX shall not have been suspended by the SEC or the AMEX.

                  (k) Opinion of Counsel. Investor shall have received an
opinion of the Company's counsel, dated as of the Second Tranche Closing Date,
in form and substance reasonably satisfactory to Investor.

                  (l) Blue Sky Law Filings. The Company shall have delivered
evidence of the qualification of the Shares under applicable state securities or
"blue sky" laws of the United States.


                                      -18-
<PAGE>   23


                  (m) Certificate of the Company's Transfer Agent. The Company
shall have delivered a certificate of the transfer agent of the Company which
sets forth the number of outstanding securities of the Company as of a date not
more than two business days prior to the Second Tranche Closing Date.

                  (n) Other Documents. Investor shall have received such other
documents and certificates, in form and substance reasonably satisfactory to
Investor and its counsel, relating to matters incident to the transactions
contemplated hereby as Investor may reasonably request.

         7. CONDITIONS TO COMPANY'S OBLIGATION AT CLOSING - THIRD TRANCHE
INVESTMENT. The obligation of the Company hereunder to issue and sell the Shares
to Investor and to take the other actions required to be taken by the Company
with respect to the Third Tranche Investment, is subject to the satisfaction on
or before the Third Tranche Closing Date, of each of the following conditions,
provided that these conditions are for the Company's sole benefit and may be
waived by the Company at any time in its sole discretion:

                  (a) Payment of Purchase Price. Investor shall have delivered
the Third Tranche Investment in accordance with Sections 1(a) and 1(d) hereof.

                  (b) Execution of EPC Agreement. The Company and Bechtel shall
have executed, and Bechtel shall have delivered, a definitive agreement setting
forth the terms by which Bechtel will perform engineering, procurement and
construction services with respect to the Wellsville Project site or an
alternate site that may be selected for the initial project (the "EPC
Agreement").

                  (c) Accuracy of Representations. All of Investor's
representations and warranties set forth herein (considered collectively), and
each of these representations and warranties (considered individually), must
have been accurate in all material respects as of the date of this Agreement and
must be accurate in all material respects as of the Third Tranche Closing Date,
as if made on such date.

                  (d) Investor's Performance.

                           (i) All of the covenants and obligations that
Investor is required to perform or to comply with pursuant to this Agreement at
or prior to the Third Tranche Closing Date (considered collectively), and each
of these covenants and obligations (considered individually), must have been
performed and complied with in all material respects.

                           (ii) Investor must have delivered each of the
documents required to be delivered by Investor pursuant this Agreement.

                  (e) No Litigation. No litigation, statute, rule, regulation,
executive order, decree, ruling or injunction shall have been enacted, entered,
promulgated or endorsed by or in any court or governmental authority of
competent jurisdiction or any self-regulatory organization having authority over
the matters contemplated hereby which prohibits the consummation of any of the
transactions contemplated by this Agreement.

         8. CONDITIONS TO INVESTOR'S OBLIGATION AT CLOSING - THIRD TRANCHE
INVESTMENT. The obligation of Investor hereunder to purchase the Shares and to
take the other actions required to be taken by Investor with respect to the
Third Tranche


                                      -19-
<PAGE>   24


Investment, is subject to the satisfaction on or before the Third Tranche
Closing Date, of each of the following conditions, provided that these
conditions are for Investor's sole benefit and may be waived by Investor at any
time in its sole discretion:

                  (a) Execution of EPC Agreement. The Company and Bechtel shall
have executed, and the Company shall have delivered, the EPC Agreement.

                  (b) Delivery of Common Stock Certificates. The Company shall
have delivered to Investor duly executed certificate(s) (in such denominations
as Investor shall reasonably request) representing the Shares to be issued in
accordance with Section 1 hereof.

                  (c) Delivery of Compliance Certificate. The Company shall have
delivered to Investor as of the Third Tranche Closing Date, a certificate signed
on its behalf by its Chief Executive Officer, Chief Financial Officer or other
authorized person, stating that there has been no material adverse change in the
business, affairs, prospects, operations, properties, assets or condition of the
Company not previously disclosed to the Investor in writing.

                  (d) Satisfaction with Terms and Conditions of Wellsville
Project Debt. A copy of all loan documentation relating to a commercial loan
transaction to be consummated for purposes of financing the development and
construction of the Wellsville Project site or an alternate site that may be
selected for the initial project, shall have been delivered to Investor. The
terms and conditions of such loan shall be deemed to be acceptable to Investor.

                  (e) Accuracy of Representations. All of the Company's
representations and warranties set forth herein (considered collectively), and
each of these representations and warranties (considered individually), must
have been accurate in all material respects as of the date of this Agreement,
and must be accurate in all material respects as of the Third Tranche Closing
Date, as if made on such date.

                  (f) The Company's Performance.

                           (i) All of the covenants and obligations that the
Company is required to perform or to comply with pursuant to this Agreement on
or before the Third Tranche Closing Date (considered collectively), and each of
these covenants and obligations (considered individually), must have been duly
performed and complied with in all material respects.

                           (ii) Each document required to be delivered by the
Company pursuant to this Agreement must have been delivered, and each of the
other covenants and obligations contained herein and therein must have been
performed and complied with by the Company in all material respects.

                  (g) No Proceedings. Since the date of this Agreement, there
must not have been commenced or threatened against Investor, or against any
person affiliated with Investor, any proceeding (i) involving any challenge to,
or seeking damages or other relief in connection with, any of the contemplated
transactions, or (ii) that may have the effect of preventing, delaying, making
illegal, or otherwise interfering with any of the contemplated transactions.

                  (h) No Claim Regarding Stock Ownership or Sale Proceeds. There
must not have been made or threatened by any person any claim asserting that
such person (i) is the holder or the beneficial owner of, or has the right to
acquire or to obtain beneficial ownership of, any stock of, or any other voting,
equity, or ownership interest in, the Company or any Subsidiary


                                      -20-
<PAGE>   25


other than as set forth in Schedule 3(c)(iii), or (ii) is entitled to all or any
portion of the Purchase Price payable for the Shares.

                  (i) No Prohibition. Neither the consummation nor the
performance of any of the contemplated transactions will, directly or indirectly
(with or without notice or lapse of time), materially contravene, or conflict
with, or result in a material violation of, or cause Investor or any person
affiliated with Investor to suffer any material adverse consequence under, (i)
any applicable legal requirement or order, or (ii) any legal requirement or
order that has been published, introduced, or otherwise proposed by or before
any governmental body.

                  (j) No Litigation. No litigation, statute, rule, regulation,
executive order, decree, ruling or injunction shall have been enacted, entered,
promulgated or endorsed by or in any court or governmental authority of
competent jurisdiction or any self-regulatory organization having authority over
the matters contemplated hereby which prohibits the consummation of any of the
transactions contemplated by this Agreement.

                  (k) Common Stock Trading. Trading in the Common Stock on the
AMEX shall not have been suspended by the SEC or the AMEX.

                  (l) Opinion of Counsel. Investor shall have received an
opinion of the Company's counsel, dated as of the Third Tranche Closing Date, in
form and substance reasonably satisfactory to Investor.

                  (m) Blue Sky Law Filings. The Company shall have delivered
evidence of the qualification of the Shares under applicable state securities or
"blue sky" laws of the United States.

                  (n) Certificate of the Company's Transfer Agent. The Company
shall have delivered a certificate of the transfer agent of the Company which
sets forth the number of outstanding securities of the Company as of a date not
more than two business days prior to the Third Tranche Closing Date.

                  (o) Other Documents. Investor shall have received such other
documents and certificates, in form and substance reasonably satisfactory to
Investor and its counsel, relating to matters incident to the transactions
contemplated hereby as Investor may reasonably request.

         9. FIRST TRANCHE ADJUSTMENT OBLIGATION OF THE COMPANY. The parties
hereby agree and acknowledge that the Price Per Share of the First Tranche
Investment was retroactively subject to the following adjustment: because the
Company issued shares of Common Stock pursuant to a private placement between
the First Tranche Closing Date and the Second Tranche Closing Date and the
issuance price per share of such Common Stock was less than the First Tranche
Price Per Share, the number of Shares issued to Investor pursuant to that
certain Stock Purchase Agreement, dated as of October 12, 2000, by and between
the parties, was adjusted and an additional 214,286 Shares shall be issued to
Investor so that the aggregate number of Shares issued to Investor with respect
to the First Tranche Investment shall be equal to the amount of the First
Tranche Investment divided by the conversion price per share of Common Stock for
which the securities purchased by the other investors in the private placement
may be converted into Common Stock (rounded up or down, as applicable, to the
nearest whole Share) during such period. The Company is in the process of
causing such additional Shares to be issued to Investor.


                                      -21-
<PAGE>   26


         10. SURVIVAL OF REPRESENTATIONS, WARRANTIES AND COVENANTS;
INDEMNIFICATION.

                  (a) Survival of Representations, Warranties and Covenants. The
representations, warranties, covenants and agreements of the Company and
Investor contained in this Agreement or in any document or certificate delivered
pursuant hereto or thereto or in connection herewith shall survive the Closing
Date last in time, and shall continue in effect until the Company's Form 10-K
(or Form 10-KSB, if applicable) for the next full fiscal year following the
fiscal year in which such Closing Date occurs, is filed with the SEC. All
statements contained in any certificate or other document delivered by or on
behalf of the Company pursuant hereto shall constitute representations and
warranties by the Company hereunder.

                  (b) Indemnification. The Company agrees to indemnify and hold
Investor harmless from and against, and will pay to Investor (including their
affiliates and their respective officers, directors, agents, attorneys,
employees and representatives) the full amount of any loss, damage, liability,
penalties or expense (including amounts paid in settlement and reasonable
attorneys' fees and expenses) to Investor resulting either directly or
indirectly from any breach of the representations, warranties, covenants or
agreements of the Company contained in this Agreement, in the Registration
Rights Agreement, in the Additional Right to Purchase Agreement, or any other
document or certificate delivered pursuant hereto or thereto or in connection
herewith or therewith.

                  (c) Claims for Indemnification; Defense of Indemnified Claims.

                           (i) For purposes of this Section 10, the party
entitled to indemnification shall be known as the "Indemnified Party" and the
party required to indemnify shall be known as the "Indemnifying Party." In the
event that the Indemnifying Party shall be obligated to the Indemnified Party
pursuant to this Section 10 or in the event that a suit, action, investigation,
claim or proceeding is begun, made or instituted as a result of which the
Indemnifying Party may become obligated to the Indemnified Party hereunder, the
Indemnified Party shall give prompt written notice to the Indemnifying Party of
the occurrence of such event, specifying the basis for such claim or demand, and
the amount or estimated amount thereof to the extent then determinable (which
estimate shall not be conclusive of the final amount of such claim or demand);
provided, however, that the failure to give such notice shall not constitute a
waiver of the right to indemnification hereunder unless the Indemnifying Party
is actually prejudiced in a material respect thereby. The Indemnifying Party
agrees to defend, contest or otherwise protect against any such suit, action,
investigation, claim or proceeding at the Indemnifying Party's own cost and
expense with counsel of its own choice, who shall be, however, reasonably
acceptable to the Indemnified Party. The Indemnifying Party may not make any
compromise or settlement without the prior written consent of the Indemnified
Party (which will not be unreasonably withheld or delayed) and the Indemnified
Party shall receive a full and unconditional release reasonably satisfactory to
it pursuant to such compromise or settlement. The Indemnified Party shall have
the right but not the obligation to participate at its own expense in the
defense thereof by counsel of its own choice. If requested by the Indemnifying
Party, the Indemnified Party shall (at the Indemnifying Party's expense) (i)
cooperate with the Indemnifying Party and its counsel in contesting any claim or
demand which the Indemnifying Party defends, (ii) provide the Indemnifying Party
with reasonable access during normal business hours to its books and records to
the extent they relate to the condition or operation of the business and are
requested by the Indemnifying Party to perform its indemnification obligations
hereunder, and to make copies of such books and records, and (iii) make
personnel available to assist in locating any books and records relating to the
business or whose assistance, participation or testimony is


                                      -22-
<PAGE>   27


reasonably required in anticipation of, preparation for or the prosecution and
defense of, any claim subject to this Section 10. In the event that the
Indemnifying Party fails timely to defend, contest or otherwise protect the
Indemnified Party against any such suit, action, investigation, claim or
proceeding, the Indemnified Party shall have the right to defend, contest or
otherwise protect itself against the same and may make any reasonable compromise
or settlement thereof and recover the entire cost thereof from the Indemnifying
Party including without limitation, reasonable attorneys' fees, disbursements
and all amounts paid as a result of such suit, action, investigation, claim or
proceeding, or compromise or settlement thereof.

         11. GENERAL PROVISIONS.

                  (a) Governing Law.

           This Agreement shall be governed by and interpreted in accordance
with the laws of the State of Texas without regard to the principles of conflict
of laws. The parties hereto hereby submit to the exclusive jurisdiction of the
United States federal courts located in Dallas, Texas with respect to any
dispute arising under this Agreement, the agreements entered into in connection
herewith or the transactions contemplated hereby or thereby.

                  (b) Counterparts; Signatures by Facsimile. This Agreement may
be executed in two or more counterparts, all of which shall be considered one
and the same agreement and shall become effective when counterparts have been
signed by each party and delivered to the other party. This Agreement, once
executed by a party, may be delivered to the other party hereto by facsimile
transmission of a copy of this Agreement bearing the signature of the party so
delivering this Agreement.

                  (c) Headings. The headings of this Agreement are for
convenience of reference and shall not form part of, or affect the
interpretation of, this Agreement.

                  (d) Severability. If any provision of this Agreement shall be
invalid or unenforceable in any jurisdiction, such invalidity or
unenforceability shall not affect the validity or enforceability of the
remainder of this Agreement or the validity or enforceability of this Agreement
in any other jurisdiction.

                  (e) Specific Performance. The parties agree that irreparable
damage will result in the event that this Agreement is not specifically
enforced, and the parties agree that any damages available at law for a breach
of this Agreement would not be an adequate remedy. Therefore, the provisions
hereof and the obligations of the parties hereunder shall be enforceable in a
court of equity, or other tribunal with jurisdiction, by a decree of specific
performance, and appropriate injunctive relief may be applied for and granted in
connection therewith. Such remedies and all other remedies provided for in this
Agreement shall, however, be cumulative and not exclusive and shall be in
addition to any other remedies which a party may have under this Agreement or
otherwise.

                  (f) Entire Agreement; Amendments. This Agreement and the
agreements, instruments, exhibits and schedules referenced herein, contain the
entire understanding of the parties with respect to the matters covered herein
and therein and, except as specifically set forth herein or therein, neither the
Company nor Investor makes any representation, warranty, covenant or undertaking
with respect to such matters. No provision of this Agreement may be waived or
amended other than by an instrument in writing signed by the party to be charged
with enforcement.


                                      -23-
<PAGE>   28


                  (g) Notices. Any notices required or permitted to be given
under the terms of this Agreement shall be sent by certified or registered mail
(return receipt requested) or delivered personally or by courier (including a
recognized overnight delivery service) or by facsimile and shall be effective
five (5) days after being placed in the mail, if mailed by regular United States
mail, or upon receipt, if delivered personally or by courier (including a
recognized overnight delivery service) or by facsimile, in each case addressed
to a party. The addresses for such communications shall be:

                  If to the Company:

                           Probex Corp.
                           One Galleria Tower
                           13355 Noel Road, Suite 1200
                           Dallas, Texas 75240
                           Attention: Chief Executive Officer
                           Facsimile: (972) 980-8545

                  With a copy to:

                           Jenkens & Gilchrist, A Professional Corporation
                           1445 Ross Ave., Suite 3200
                           Dallas, Texas 75202
                           Attention: Robert Dockery, Esq.
                           Facsimile: (214) 855-4300

                  If to Investor:

                           United Infrastructure Company, LLC
                           50 California Street, Suite 2200
                           San Francisco, California 94111
                           Attention: Chief Operating Officer
                           Facsimile: (415) 768-1714

                  With a copy to:

                           Bechtel Enterprises Holdings, Inc.
                           50 California Street, Suite 2200
                           San Francisco, California 94111
                           Attention: Chief Counsel
                           Facsimile: (415) 768-2233

         Each party shall provide notice to the other party of any change in
address or facsimile number.

                  (h) Successors and Assigns. This Agreement shall be binding
upon and inure to the benefit of the parties and their successors and assigns.
Neither the Company nor Investor shall assign this Agreement or any rights or
obligations hereunder without the prior written consent of the other party.
Notwithstanding the foregoing, subject to Section 2(f), Investor may assign its
rights hereunder to any person that purchases Shares in a private transaction
from Investor or to any of its "affiliates," as that term is defined under the
Exchange Act, without the consent of the Company.


                                      -24-
<PAGE>   29


                  (i) Third Party Beneficiaries. This Agreement is intended for
the benefit of the parties hereto and their respective permitted successors and
assigns, and is not for the benefit of, nor may any provision hereof be enforced
by, any other person.

                  (j) Publicity. The Investor shall have the right to review a
reasonable period of time before issuance of any press releases, SEC, AMEX, or
NASD filings, or any other public statements with respect to the transactions
contemplated hereby; provided, however, that the Company shall be entitled,
without the prior approval of Investor, to make any press release or SEC, AMEX,
or NASD filings with respect to such transactions as is required by applicable
law and regulations (although Investor shall be consulted by the Company in
connection with any such press release prior to its release and shall be
provided with a copy thereof and be given an opportunity to comment thereon).

                  (k) Further Assurances. Each party shall do and perform, or
cause to be done and performed, all such further acts and things, and shall
execute and deliver all such other agreements, certificates, instruments and
documents, as the other party may reasonably request in order to carry out the
intent and accomplish the purposes of this Agreement and the consummation of the
transactions contemplated hereby.

                  (l) Limited Recourse. Notwithstanding anything in this
Agreement, the Registration Rights Agreement or any other document, agreement or
instrument contemplated hereby or thereby to the contrary, the obligations of
Investor hereunder and under the Registration Rights Agreement shall be without
recourse to any partner, affiliate of Investor or their respective partners, or
any other respective officers, directors, employees or agents and shall be
limited to the assets of Investor.

                  (m) Waiver. Any term or condition of this Agreement may be
waived at any time by the party that is entitled to the benefit thereof, but no
such waiver shall be effective unless set forth in a written instrument duly
executed by or on behalf of the party waiving such term or condition. No waiver
by any party of any term or condition of this Agreement, in any one or more
instances, shall be deemed to be or construed as a waiver of the same or any
other term or condition of this Agreement on any future occasion. All remedies,
either under this Agreement or by law or otherwise afforded, will be cumulative
and not alternative.

                  (n) No Strict Construction. The language used in this
Agreement will be deemed to be the language chosen by the parties to express
their mutual intent, and no rules of strict construction will be applied against
any party.

                  [REMAINDER OF PAGE INTENTIONALLY LEFT BLANK.]


                                      -25-
<PAGE>   30


         IN WITNESS WHEREOF, the Company and Investor have caused this Agreement
to be duly executed as of the date first above written.



                                         PROBEX CORP.,
                                         a Delaware corporation


                                         By:   /s/ JOHN N. BROBJORG
                                              -------------------------------
                                              John N. Brobjorg
                                              Corporate Controller


                                         UNITED INFRASTRUCTURE COMPANY, LLC,
                                         a Delaware limited liability company


                                         By:   /s/ NORA A. BLUM
                                              -------------------------------
                                              Nora A. Blum
                                              Authorized Person



                 [Schedules and Exhibits Intentionally Omitted]