<PAGE>


                                                                  EXECUTION COPY


                        VOTING AND DISPOSITION AGREEMENT

                  This VOTING AND DISPOSITION AGREEMENT, dated as of July 13,
2000 (this "AGREEMENT"), by and among Hanover Compressor Company, a Delaware
corporation ("PARENT"), and the undersigned holders (collectively, the "HOLDERS"
and each a "HOLDER") of shares of common stock, par value $.01 per share
("COMPANY COMMON STOCK"), of OEC Compression Corporation, an Oklahoma
corporation (the "COMPANY").

                                    RECITALS

                  WHEREAS, the Company, Parent and Caddo Acquisition
Corporation, an Oklahoma corporation and a wholly-owned subsidiary of Parent
("MERGER SUB"), propose to enter into an Agreement and Plan of Merger dated as
of the date hereof (the "MERGER AGREEMENT"; capitalized terms used and not
defined herein having the meanings given them in the Merger Agreement), pursuant
to which Merger Sub would be merged with and into the Company (the "MERGER"),
and each outstanding share of Company Common Stock would be converted into the
right to receive shares of common stock, par value $.001 per share, of Parent
("PARENT COMMON STOCK");

                  WHEREAS, as a condition of its entering into the Merger
Agreement, Parent has requested each Holder to agree, and each Holder hereby
agrees, to enter into this Agreement;

                  WHEREAS, prior to the date hereof, Parent and the Holders had
no agreement, arrangement or understanding (as such terms are used in Section
1090.3 of the Oklahoma General Corporation Law (the "OGCL")) for the purpose of
acquiring, holding, voting or disposing of shares of Company Common Stock; and

                  WHEREAS, in consideration for the agreements contained herein,
prior to the execution hereof, and prior to Parent becoming an "interested
stockholder" for purposes of Section 1090.3 of the OGCL, the Board of Directors
of the Company has approved this Agreement, the Merger Agreement and the
transactions contemplated hereby and thereby, including the agreement of the
Holders to vote as provided in Section 2 of this Agreement and not to transfer
shares of Company Common Stock as provided in Section 6(B) of this Agreement.

                                    AGREEMENT

                  NOW, THEREFORE, the parties hereto agree as follows:

         1     REPRESENTATIONS AND WARRANTIES OF THE HOLDERS. Each Holder
represents and warrants, severally and not jointly, to Parent as follows:

               A.  OWNERSHIP OF SECURITIES. As of the date hereof, such Holder
         is the record and/or beneficial owner of the number of shares of
         Company Common Stock (the "EXISTING SECURITIES") (together with any
         shares of Company Common Stock or other securities, of the Company
         hereafter acquired by the Holder through purchase, exercise of

<PAGE>


         options or warrants or otherwise, the "SUBJECT SECURITIES") set
         forth on the signature page to this Agreement. Such Holder does not
         beneficially or of record own any securities of the Company on the
         date hereof other than the Existing Securities. Such Holder has sole
         voting power and sole power to issue instructions with respect to
         the voting of the Existing Securities, sole power of disposition,
         sole power of exercise and the sole power to demand appraisal
         rights, in each case with respect to all of the Existing Securities,
         and, on the date of the Company Stockholders' Meeting (as defined in
         the Merger Agreement), will have the sole voting power and power to
         issue instructions with respect to the voting of all of such Holder's
         Subject Securities, the sole powers of disposition, exercise and the
         sole power to demand appraisal rights, in each case with respect to
         all of such Holder's Subject Securities.

               B.  AUTHORITY; BINDING AGREEMENT. Each Holder has the legal
         capacity, power and authority to enter into and perform all of such
         Holder's obligations under this Agreement. The execution, delivery and
         performance of this Agreement by each Holder will not violate any other
         agreement relating to the Subject Securities to which the Holder is a
         party, including, without limitation, any voting agreement,
         stockholder's agreement, partnership agreement or voting trust. This
         Agreement has been duly and validly executed and delivered by such
         Holder and constitutes a valid and binding agreement of such Holder,
         enforceable against such Holder in accordance with its terms, except
         that (i) such enforcement may be subject to applicable bankruptcy,
         insolvency or other similar laws, now or hereafter in effect, affecting
         creditors' rights generally, and (ii) the remedy of specific
         performance and injunctive and other forms of equitable relief may be
         subject to equitable defenses and to the discretion of the court before
         which any proceeding therefor may be brought.

               C.  NO CONFLICTS. No filing with, and no permit, authorization,
         consent or approval of, any local, state or federal public body or
         authority is necessary for the execution of this Agreement by such
         Holder and the consummation by such Holder of the transactions
         contemplated hereby, and neither the execution and delivery of this
         Agreement by such Holder, nor the consummation by such Holder of the
         transactions contemplated hereby nor compliance by such Holder with any
         of the provisions hereof shall conflict with or result in any breach of
         any applicable corporate, partnership or other organizational documents
         applicable to such Holder, result in a violation or breach of, or
         constitute (with or without notice or lapse of time or both) a default
         (or give rise to any third-party right of termination, cancellation,
         material modification or acceleration) under any of the terms,
         conditions or provisions of any note, bond, mortgage, indenture,
         license, contract, commitment, arrangement, understanding, agreement or
         other instrument or obligation of any kind to which such Holder is a
         party or by which such Holder's properties or assets may be bound or
         violate any order, writ, injunction, decree, judgment, statute, rule or
         regulation applicable to such Holder or any of such Holder's properties
         or assets.

               D.  NO ENCUMBRANCES. The Subject Securities are now, and at all
         times during the term hereof will be, held by such Holder, or by a
         nominee or custodian for the benefit


                                       2
<PAGE>


         of such Holder, free and clear of all liens, claims, options,
         charges, security interests, proxies, voting trusts or agreements,
         understandings or arrangements or any other encumbrances or proxies
         whatsoever (collectively, "ENCUMBRANCES"), except for any encumbrances
         or proxies arising hereunder.

               E.  NO FINDER'S FEES. No broker, investment banker, financial
         advisor or other Person (as defined below) is entitled to any broker's,
         finder's, financial advisor's or other similar fee or commission in
         connection with the transactions contemplated hereby based upon
         arrangements made by or on behalf of the Holder except that the Company
         has employed Prudential Securities as its financial advisor, the
         arrangements with which have been disclosed in writing to Parent and
         Merger Sub prior to, and will not be modified subsequent to, the date
         of the Merger Agreement. "PERSON" shall mean any individual,
         corporation, partnership, limited liability company, sole
         proprietorship, trust, joint venture, firm, association, company or
         other entity.

               F.  NO OTHER AGREEMENTS.  Except pursuant to the Merger
         Agreement, no Holder has a legal obligation, absolute or contingent, to
         any other Person to sell, dispose of or otherwise transfer all or any
         portion of the Subject Securities.

               G.  RELIANCE BY PARENT. The Holders understand and acknowledge
         that Parent is entering into, and causing Merger Sub to enter into, the
         Merger Agreement in reliance upon the Holder's execution, delivery and
         performance of this Agreement.

         2    AGREEMENT TO VOTE SHARES. During the period commencing on the
date hereof and continuing until the first to occur of (i) the Effective Time
and (ii) the termination of the Merger Agreement, at every meeting of the
stockholders of the Company however called and at every adjournment thereof, and
on every action or approval by written consent of the stockholders of the
Company with respect to any of the following, each Holder, severally and not
jointly, agrees that it shall vote (or caused to be voted), or execute a written
consent with respect to, as appropriate, all of the Subject Securities as to
which it has power to vote in any such vote or consent: (i) in favor of the
Merger, the adoption of and execution and delivery by the Company of the Merger
Agreement and the approval of the terms thereof and each of the other
transactions contemplated by the Merger Agreement and (ii) against the following
actions (other than the Merger and the transactions contemplated by the Merger
Agreement): (1) any merger, consolidation, business combination,
recapitalization, sale of substantial assets, sale or acquisition of shares of
capital stock (including, without limitation, by way of a tender offer) or
similar transaction involving the Company or any of its subsidiaries; (2)(a)
any amendment of the Company's certificate of incorporation or bylaws or any
change in the majority of the Board of Directors of the Company; (b) any
material change in the present capitalization of the Company; (c) any other
material change in the Company's corporate structure or business; or (d) any
other action, which, in the case of each of the matters referred to in clauses
(a), (b) or (c) above, is intended, or could reasonably be expected, to impede,
interfere with, delay, postpone, discourage or materially adversely affect the
consummation of the Merger or the transactions contemplated by the Merger
Agreement or this Agreement; and (3) any action or agreement that would result
in a breach in any respect of any covenant, representation or warranty or any
other


                                       3
<PAGE>


obligation or agreement of the Company under the Merger Agreement or of a
Holder under this Agreement.

         3    IRREVOCABLE PROXY. EACH HOLDER HEREBY, SEVERALLY AND NOT JOINTLY,
GRANTS TO, AND APPOINTS MERGER SUB AND THE PRESIDENT OF MERGER SUB AND THE
TREASURER OF MERGER SUB, IN THEIR RESPECTIVE CAPACITIES AS OFFICERS OF MERGER
SUB, AND ANY INDIVIDUAL WHO SHALL HEREAFTER SUCCEED TO ANY SUCH OFFICE OF MERGER
SUB, AND ANY OTHER DESIGNEE OF MERGER SUB, EACH OF THEM INDIVIDUALLY, SUCH
HOLDER'S PROXY WITH RESPECT TO THE SUBJECT SECURITIES AND ATTORNEY-IN-FACT (WITH
FULL POWER OF SUBSTITUTION) TO VOTE OR ACT BY WRITTEN CONSENT WITH RESPECT TO
SUCH HOLDER'S SUBJECT SECURITIES IN ACCORDANCE WITH SECTION 2 HEREOF. THIS PROXY
IS COUPLED WITH AN INTEREST AND SHALL BE IRREVOCABLE. EACH HOLDER WILL TAKE SUCH
FURTHER ACTION OR EXECUTE SUCH OTHER INSTRUMENTS, INCLUDING, WITHOUT LIMITATION,
THE FORM OF PROXY ATTACHED HERETO AS EXHIBIT A (THE "PROXY") AS MAY BE
REASONABLY NECESSARY TO EFFECTUATE THE INTENT OF THIS PROXY AND HEREBY REVOKES
ANY PROXY PREVIOUSLY GRANTED BY IT WITH RESPECT TO THE SUBJECT SECURITIES. AS
PROMPTLY AS PRACTICABLE, EACH HOLDER SHALL MAKE ALL FILINGS AND GIVE ALL NOTICES
WITH RESPECT TO THE PROXY AS MAY BE REQUIRED BY APPLICABLE LAW. THE HOLDER SHALL
NOT ENTER INTO ANY AGREEMENT OR UNDERSTANDING WITH ANY PERSON, THE EFFECT OF
WHICH WOULD BE INCONSISTENT WITH, OR VIOLATIVE OF, THE PROVISIONS AND AGREEMENTS
CONTAINED IN THIS SECTION 3.

         4    RESTRICTIONS ON TRANSFER OF PARENT COMMON STOCK. Each of the
Holders, hereby agree that such Holder shall not, directly or indirectly,
during a period of 120 days from the Effective Time (the "STANDSTILL
PERIOD"), without the prior written consent of Parent, sell, offer or agree
to sell or otherwise dispose of any Parent Common Stock received by such
Holder pursuant to the Merger. Each Holder further agrees that, for each
succeeding 30-day period following the Standstill Period, such Holder shall
not, directly or indirectly, without the written consent of Parent, sell,
offer or agree to sell or otherwise dispose of, more than 15% of the shares
of Parent Common Stock such Holder receives in connection with the Merger.
Each Holder acknowledges and agrees that the certificates representing such
Holder's Parent Common Stock will bear a legend in substantially the
following form:

         THE SECURITIES REPRESENTED BY THIS CERTIFICATE ARE SUBJECT TO CERTAIN
         RESTRICTIONS ON TRANSFER SET FORTH IN THAT CERTAIN VOTING AND
         DISPOSITION AGREEMENT DATED AS OF JULY __, 2000 BY AND AMONG THE
         RESTRICTED HOLDERS (AS DEFINED THEREIN), HANOVER COMPRESSOR COMPANY AND
         CADDO ACQUISITION CORPORATION.


                                       4
<PAGE>


5.       REPRESENTATIONS AND WARRANTIES OF PARENT.

               A.  POWER; BINDING AGREEMENT. Parent has full corporate power
         and authority to enter into and perform all of Parent's obligations
         under this Agreement. This Agreement has been duly and validly executed
         and delivered by Parent and constitutes a valid and binding agreement
         of Parent, enforceable against Parent in accordance with its terms,
         except that (i) such enforcement may be subject to applicable
         bankruptcy, insolvency or other similar laws, now or hereafter in
         effect, affecting creditors' rights generally, and (ii) the remedy of
         specific performance and injunctive and other forms of equitable relief
         may be subject to equitable defenses and to the discretion of the court
         before which any proceeding therefor may be brought.

               B.  NO CONFLICTS. No filing with, and no permit, authorization,
         consent or approval of, any state or federal public body or authority
         is necessary for the execution of this Agreement by Parent and the
         consummation by Parent of the transactions contemplated hereby and
         neither the execution and delivery of this Agreement by Parent nor the
         consummation by Parent of the transactions contemplated hereby, nor
         compliance by Parent with any of the provisions hereof shall conflict
         with or result in any breach of any organizational documents applicable
         to Parent, or result in a violation or breach of, or constitute (with
         or without notice or lapse of time or both) a default, or give rise to
         any third-party right of termination, cancellation, material
         modification or acceleration under any of the terms, conditions or
         provisions of any note, bond, mortgage, indenture, license, contract,
         commitment, arrangement, understanding, agreement or other instrument
         or obligation of any kind to which Parent is a party or by which
         Parent's properties or assets may be bound, or violate any order, writ,
         injunction, decree, judgment, statute, rule or regulation applicable to
         Parent or any of Parent's properties or assets, except for any such
         conflicts, breaches, defaults or violations as would not materially
         impair Parent's performance of its obligations hereunder.

         6    COVENANTS OF THE HOLDERS.  Each Holder, severally and not jointly,
hereby agrees and covenants that:

               A.  NO SOLICITATION. Such Holder (and Persons acting on behalf
         of the Holder) shall not, directly or indirectly, solicit (including by
         way of furnishing information), initiate, encourage or respond to, or
         take any other action knowingly to facilitate any inquiries or the
         making of any proposal by any Person with respect to the Company that
         constitutes, or could reasonably be expected to lead to, an Acquisition
         Proposal or permit or authorize any Person acting on behalf of the
         Holder to do any of the foregoing. If any Holder receives any such
         inquiry or proposal, then it shall immediately inform Parent of all
         terms and conditions, if any, of such inquiry or proposal and the
         identity of the person making it and shall, in the case of written
         proposals or inquiries, furnish Parent with a copy of such proposal or
         inquiry (and all amendments and supplements thereto). Such Holder will
         immediately cease and cause to be terminated any existing activities,
         discussions or negotiations with any parties conducted heretofore with
         respect to any of the foregoing.


                                       5
<PAGE>


               B.  RESTRICTION ON TRANSFER OF COMPANY COMMON STOCK, PROXIES
         AND NONINTERFERENCE. Such Holder shall not, prior to the termination of
         this Agreement, directly or indirectly, except pursuant to the terms of
         the Merger Agreement or this Agreement: (i) offer for sale, sell,
         transfer (whether by merger, operation of law or otherwise), tender,
         pledge, encumber, assign or otherwise dispose of, or enter into any
         contract, option or other arrangement or understanding with respect to
         or consent to the offer for sale, sale, transfer, tender, pledge,
         encumbrance, assignment or other disposition of, any or all of such
         Holder's Subject Securities; (ii) grant any proxies or powers of
         attorney, deposit any such Subject Securities into a voting trust or
         enter into a voting agreement with respect to any of such Holder's
         Subject Securities; or (iii) take any action that would make any
         representation, warranty, covenant or other provision contained herein
         untrue or incorrect or have the effect of, or could reasonably be
         expected to, impede, interfere with, delay, postpone, discourage or
         materially adversely affect such Holder from performing its obligations
         under this Agreement. The Holder's Company Common Stock certificates
         shall be legended to reflect the above restrictions.

               C.  WAIVER OF APPRAISAL RIGHTS. Such Holder hereby irrevocably
         waives any rights of appraisal or rights to dissent, if any, from the
         Merger that the Holder may now or hereafter have.

               D.  STOP TRANSFER; CHANGES IN SUBJECT SECURITIES. Such Holder
         shall not request that the Company register the transfer (book-entry or
         otherwise) of any certificate or uncertificated interest representing
         any of the Subject Securities, unless such transfer is made in
         compliance with this Agreement. In the event of a stock dividend or
         distribution, or any change in the Company Common Stock by reason of
         any stock dividend, split-up, merger, recapitalization, combination,
         conversion or exchange of shares or the like (in each case with a
         record date prior to the termination of this Agreement), the term
         "Subject Securities" shall be deemed to refer to and include the
         Subject Securities as well as all such stock dividends and
         distributions and any securities into which or for which any or all of
         the Subject Securities may be changed or exchanged and such dividends,
         distributions and securities, as the case may be, shall be paid to
         Parent at the Closing or promptly following the receipt of such
         dividend or distribution, if the Closing theretofor shall have
         occurred.

               E.  CONFIDENTIALITY. Such Holder recognizes that successful
         consummation of the transactions contemplated by this Agreement and the
         Merger Agreement may be dependent upon confidentiality with respect to
         the matters referred to herein. In this connection, pending public
         disclosure thereof in accordance with the provisions of the Merger
         Agreement, the Holder hereby agrees not to disclose or discuss such
         matters with any Person (other than Parent or Merger Sub and the
         respective counsel and advisors of the Holders, Parent and Merger Sub)
         without the prior written consent of Parent, except for filings
         required pursuant to the Exchange Act and the rules and regulations
         thereunder or disclosures necessary in order to fulfill the Holder's
         obligations imposed by law, in which event the Holder shall give prior
         written notice of such disclosure to Parent as


                                       6
<PAGE>


         promptly as practicable so as to enable Parent to seek a protective
         order from a court of competent jurisdiction with respect thereto.

         7    FIDUCIARY DUTIES. Notwithstanding anything in this Agreement to
the contrary, the covenants and agreements set forth herein shall not prevent
any Holders serving on the Company's Board of Directors from taking any action,
subject to applicable provisions of the Merger Agreement, which such director
shall determine in good faith, after consultation with legal counsel, to be
required by his fiduciary duties to the Company or its stockholders while
acting in such person's capacity as a director of the Company.

         8    ASSIGNMENT; BENEFITS.  This Agreement may be assigned, in whole
or in part, by Parent to Merger Sub or any other wholly-owned subsidiary of
Parent, to the extent and for so long as such subsidiary remains a
wholly-owned subsidiary of Parent. Other than as permitted in the preceding
sentence, this Agreement may not be assigned by any party hereto without the
prior written consent of the other party. This Agreement shall be binding
upon, and shall inure to the benefit of, the Holder, Parent and their
respective successors and permitted assigns.

         9    NOTICES. All notices and other communications hereunder shall
be in writing and shall be deemed given if delivered personally, telecopied
(which is confirmed) or mailed by registered or certified mail (return
receipt requested) to the parties at the following addresses (or at such
other address for a party as shall be specified by like notice):

         (a)  if to a Holder, to:

                   The corresponding address set forth on the signature pages
              hereto;

         (b)       if to Parent, to:

                                   Hanover Compressor Company
                                   12001 N. Houston Rosslyn Road
                                   Houston, Texas 77086
                                   Attention:  Michael J. McGhan
                                   Telecopy:  (281) 447-0821

                                   with a copy to:

                                   Latham & Watkins
                                   233 South Wacker Drive
                                   Suite 5800
                                   Chicago, Illinois 60606
                                   Attention:  Richard Meller, Esq.
                                   Telecopy:  (312) 993-9767

         10   SPECIFIC PERFORMANCE. The parties hereto agree that irreparable
harm would occur in the event that any of the provisions of this Agreement
were not performed in accordance with its specific terms or were otherwise
breached. It is accordingly agreed that the parties shall be


                                       7
<PAGE>


entitled to an injunction or injunctions to prevent breaches of this Agreement
and to enforce specifically the terms and provisions hereof in any court of the
United States or any state thereof having jurisdiction, this being in addition
to any other remedy to which they are entitled at law or in equity.

         11   AMENDMENT. This Agreement may not be amended or modified,
except by an instrument in writing signed by or on behalf of each of the
parties hereto. This Agreement may not be waived by either party hereto,
except by an instrument in writing signed by or on behalf of the party
granting such waiver.

         12   GOVERNING LAW. The laws of the State of Oklahoma shall govern the
interpretation, validity and performance of the terms of this Agreement,
regardless of the law that might be applied under principles of conflicts of
law. Any suit, action or proceeding by a party hereto with respect to this
Agreement, or any judgment entered by any court in respect of any thereof, may
be brought in any state or federal court of competent jurisdiction in Houston,
Texas and each party hereto hereby submits to the exclusive jurisdiction of such
courts for the purpose of any such suit, action, proceeding or judgment. Each
party hereto hereby irrevocably waives any objections which it may now or
hereafter have to the laying of the venue of any suit, action or proceeding
arising out of or relating to this Agreement brought in any state or federal
court of competent jurisdiction in Houston, Texas and hereby further irrevocably
waives any claim that any such suit, action or proceeding brought in any such
court has been brought in any inconvenient forum. No suit, action or proceeding
against a party hereto with respect to this Agreement may be brought in any
court, domestic or foreign, or before any similar domestic or foreign authority
other than in a court of competent jurisdiction Houston, Texas and each party
hereto hereby irrevocably waives any right which it may otherwise have had to
bring such an action in any other court, domestic or foreign, or before any
similar domestic or foreign authority.

         13   COUNTERPARTS. 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 two or more counterparts have been signed by each of
the parties and delivered to the other parties, it being understood that all
parties need not sign the same counterpart.

         14   TERMINATION. This Agreement shall terminate upon the earlier of
(i) the Effective Time or (ii) the date of termination of the Merger
Agreement. Upon any termination of this Agreement, this Agreement shall
thereupon become void and of no further force and effect, and there shall be
no liability in respect of this Agreement or of any transactions contemplated
hereby or by the Merger Agreement on the part of any party hereto or any of
its directors, officers, partners, stockholders, employees, agents, advisors,
representatives or affiliates; provided, however, that nothing herein shall
relieve any party from any liability for such party's willful breach of this
Agreement; and provided further that nothing herein shall limit, restrict,
impair, amend or otherwise modify the rights, remedies, obligations or
liabilities of any Person under any other contract or agreement, including,
without limitation, the Merger Agreement.


                                       8
<PAGE>


         15   FURTHER ASSURANCES. From time to time, at the other party's
request and without further consideration, each party hereto shall execute
and deliver such additional documents and take all such further lawful action
as may be necessary or appropriate to consummate and make effective, in the
most expeditious manner practicable, the transactions contemplated by this
Agreement.

         16   ENTIRE AGREEMENT; NO THIRD PARTY BENEFICIARIES. This Agreement,
together with the Merger Agreement, constitutes the entire agreement between the
parties hereto with respect to the subject matter hereof and supersedes all
other prior agreements and understandings, both written and oral, between the
parties hereto with respect to the subject matter hereof. This Agreement is not
intended for the benefit of or intended to confer upon any Person other than the
parties hereto any rights or remedies hereunder.

         17   CERTAIN EVENTS. Each Holder agrees that this Agreement and the
obligations hereunder shall attach to the Subject Securities and shall be
binding upon any Person to which legal or beneficial ownership of such Subject
Securities shall pass, whether by operation of law or otherwise, including,
without limitation, the Holder's heirs, guardians, administrators or successors.
Notwithstanding any transfer of Subject Securities, the transferor shall remain
liable for the performance of all obligations of the transferor under this
Agreement.

         18   DESCRIPTIVE HEADINGS. The descriptive headings used herein are
inserted for convenience of reference only and are not intended to be part of or
to affect the meaning or interpretation of this Agreement.

         19   SEVERABILITY. Whenever possible, each provision or portion of any
provision of this Agreement will be interpreted in such manner as to be
effective and valid under applicable law, but if any provision or portion of any
provision of this Agreement is held to be invalid, illegal or unenforceable in
any respect under any applicable law or rule in any jurisdiction, such
invalidity, illegality or unenforceabilty will not affect any other provision or
portion of any provision in such jurisdiction, and this Agreement will be
reformed, construed and enforced in such jurisdiction as if such invalid,
illegal or unenforceable provision or portion of any provision had never been
contained herein.

         20   REMEDIES CUMULATIVE. All rights, powers and remedies provided
under this Agreement or otherwise available in respect hereof at law or in
equity shall be cumulative and not alternative, and the exercise of any
thereof by either party hereto shall not preclude the simultaneous or later
exercise of any other such right, power or remedy by such party.

         21   NO WAIVER. The failure of either party hereto to exercise any
right, power or remedy provided under this Agreement or otherwise available
in respect hereof at law or in equity, or to insist upon compliance by the
other party hereto with its obligations hereunder, and any custom or practice
of the parties hereto at variance with the terms hereof shall not constitute
a waiver by such party of its or his right to exercise any such or other
right, power or remedy or to demand such compliance.


                            [SIGNATURE PAGE FOLLOWS]


                                       9
<PAGE>


         IN WITNESS WHEREOF, this Agreement has been executed by or on behalf
of each of the parties hereto, all as of the date first above written.

                                     HANOVER COMPRESSOR COMPANY

                                     By:
                                        ---------------------------------------
                                     Its:
                                         --------------------------------------


                                     HOLDERS:


                                     HACL, Ltd.
                                     By: Six-Dawaco, Inc., its general partner

                                     By:
                                        ---------------------------------------
                                     Its:
                                         --------------------------------------
                                     Address:    2838 Woodside
                                                 Dallas, Texas 75201
                                     Telecopy:   (214) 981-0700

                                     Energy Investors Joint Venture
                                     By: HACL, Ltd., its managing joint venture
                                         partner
                                     By: Six-Dawaco, Inc., its general partner

                                     By:
                                        ---------------------------------------
                                     Its:
                                         --------------------------------------
                                     Address:    2838 Woodside
                                                 Dallas, Texas 7201
                                     Telecopy:   (214) 981-0700



                                     B-1
<PAGE>


                                                                       EXHIBIT A

                            FORM OF IRREVOCABLE PROXY

              Pursuant to Section 3 of the Voting and Disposition Agreement,
dated as of July 13, 2000, as the same may be amended from time to time, (the
"VOTING AGREEMENT"), between Hanover Compressor Company, a Delaware corporation
("PARENT") and the undersigned stockholders (collectively, the "HOLDERS" and
each a "Holder") of shares of common stock, par value $.01 per share ("COMPANY
COMMON STOCK"), of OEC Compression Corporation, an Oklahoma corporation (the
"COMPANY"), the undersigned hereby irrevocably appoint Caddo Acquisition Corp.,
a Delaware corporation and a wholly-owned subsidiary of Parent ("MERGER SUB"),
Michael J. McGhan, and William S. Goldberg, and each of them, or any other
designee of Parent or Merger Sub, their attorneys-in-fact and proxies of the
undersigned, each with full power of substitution:

              (a)  to attend any meeting (whether annual or special or both)
of the stockholders of the Company, including any adjournment or postponement
thereof, on behalf of the undersigned, and at such meeting, with respect to all
shares of common stock of the Company owned (or beneficially owned) by the
undersigned on the date hereof or acquired hereafter that are entitled to vote
at such meeting or over which the undersigned has voting power (and any and all
other shares of common stock of the Company or other securities issued on or
after the date hereof in respect of any such shares), including, without
limitation, the shares indicated in the last paragraph of this proxy:

                   (i)   to vote (in person or by proxy) in favor of the
approval of the plan of merger contained in Agreement and Plan of Merger, dated
as of July 13, 2000, by and among Parent, Merger Sub and the Company (as the
same may be amended from time to time, the "MERGER AGREEMENT"), and in favor of
any other action related to the Merger (as defined in the Merger Agreement) or
in furtherance of the transactions contemplated by the Merger Agreement, and
otherwise to act with respect to such shares as each such attorney and proxy or
his or her substitute shall in his or her reasonable discretion deem necessary
or appropriate for such purpose; and

                   (ii)  to vote (in person or by proxy) against (A) any
merger agreement or merger (other than the Merger Agreement and the Merger),
consolidation, liquidation, dissolution, recapitalization, reorganization,
winding up or other business combination, acquisition or sale or other
disposition of a material amount of assets or securities, tender offer or
exchange offer or any other similar transaction involving the Company, its
securities or any of its material subsidiaries or divisions, (B) any action
or agreement that would result in a breach in any respect of any covenant,
representation or warranty or any other obligation or agreement of the
Company under the Merger Agreement or of any Holder under the Voting Agreement,
(C) any change in the present capitalization of the Company or any amendment
of Company's articles of incorporation or by-laws, (D) any other material
change in the Company's corporate structure or business and (E) any other
action involving the Company or its subsidiaries which is


                                     B-2
<PAGE>


intended, or could reasonably be expected, to impede, interfere with, delay,
postpone, or otherwise adversely affect the Merger or any transaction
contemplated by the Merger Agreement; and

         (b)  to execute and deliver one or more consents in writing in lieu
of such meeting or adjournment thereof.

         The undersigned affirms that this proxy is issued in connection with
the Merger Agreement to facilitate the transactions contemplated thereunder
and in consideration of Parent entering into the Merger Agreement and as such
is coupled with an interest and is irrevocable. This proxy will terminate
upon the termination of the Merger Agreement in accordance with its terms.
For purposes of this proxy, any written consent shall be deemed delivered to
such attorneys and proxies and their substitutes when delivered to Merger Sub
in accordance with the Merger Agreement, and any written consent shall be
deemed delivered to the Company when delivered to it in accordance with the
Merger Agreement.

         By execution and delivery of this proxy to the designees of Merger
Sub, the undersigned (a) confirms that the undersigned has received copies of
the Merger Agreement and the Voting Agreement, and that all other information
deemed necessary by the undersigned concerning the Merger, the Merger
Agreement, the Voting Agreement and the transactions contemplated under any
such agreements or any other matters considered by the undersigned to be
relevant to the undersigned's decision to execute this proxy have been made
available to the undersigned and (b) agrees that the undersigned win not
sell, transfer or otherwise dispose of any Subject Shares (as defined in the
Voting Agreement) prior to the termination of the Voting Agreement.

         All authority herein conferred or agreed to be conferred shall
survive the death, liquidation or incapacity of the undersigned and any
obligation of the undersigned hereunder shall be binding upon the heirs,
personal representatives, successors and assigns of the undersigned. This
proxy revokes any and all other proxies heretofore granted by the undersigned
to vote or otherwise to act with respect to any of the shares to which this
proxy relates. The undersigned will not give any subsequent proxy (and such
proxy if given will be deemed not to be effective) with respect to such
shares that purports to grant authority within the scope of the authority
hereby conferred, except on the express condition that such proxy shall not
be effective unless and until this proxy shall have terminated in accordance
with its terms. This proxy shall be governed by the internal laws of the
State of Delaware.


                                     B-3
<PAGE>


         As of the date hereof, the undersigned owns or possesses voting power
with respect to shares of _________ common stock, par value $.01 per share, of
the Company, and such shares are entitled to vote with respect the approval by
the stockholders of the Company of the plan of merger set forth in the Merger
Agreement and each of the other transactions contemplated by the Merger
Agreement.

                                           By:
                                              -------------------------------
                                                   [HOLDER]











                                     B-4