Document:

GUARANTY & AGREEMENT

Guaranty  and  Agreement  ("Guaranty") between the Guarantor named below and RZB
FINANCE  LLC  (together  with  its  successors  and assigns, "RZB"), dated as of
September  15,  2004.

1.   SPECIAL  TERMS

     The  following  terms  and  provisions  shall  apply  to this Guaranty; the
     meaning of any term in this or other sections of this Guaranty expressed in
     the  singular  shall apply, mutatis mutandis, to the same term expressed in
                                 ------- --------
     the  plural  and  vice  versa.
                       ----  -----

     BORROWER:  Penn  Octane  Corporation,  a  Delaware  corporation

     GUARANTOR  :  Rio  Vista  Operating  Partnership  L.P.,  a Delaware limited
     partnership

     GUARANTEED  OBLIGATIONS:  All  indebtedness,  liabilites and obligations of
     the  Borrower  to  RZB now existing or hereafter arising including, but not
     limited  to,  those  arising  under  the following documents (including any
     modifications  thereof  or  substitutions  therefor, the "Loan Documents"):

     DOCUMENTS:  Amended  and  Restated  Line  Letter, dated as of September 15,
     2004,  (the  "Line  Letter"), General Security Agreement, dated October 18,
     2002,  Continuing  Agreement for Letters of Credit, dated October 14, 1997,
     Promissory  Note,  dated  September  15,  2004

2.   GUARANTY

     2.1  Continuing  Guaranty  of Payment.  In consideration of RZB agreeing to
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     the Loan Documents and/or extending or continuing credit to the Borrower in
     connection  therewith,  the  Guarantor  irrevocably,  absolutely  and
     unconditionally  guarantees  to  RZB the payment when due of all Guaranteed
     Obligations,  together  with  interest  thereon  and  other charges related
     thereto. For purposes of this Guaranty, the Guaranteed Obligations shall be
     due  on  the  earliest  of:

     2.a. the  due  date  thereof  (by  acceleration  or  otherwise),

     2.b. with  respect  to  any  obligation due on demand, upon demand therefor
          made  by  RZB  upon  the  Borrower  or  the  Guarantor,

     2.c. the  giving  of  notice  by  RZB  to  the Borrower or Guarantor of the
          occurrence  of  any  default by the Guarantor hereunder (including any
          material  misrepresentation  by  the Guarantor herein or in connection
          herewith),

     2.d. the  occurrence  of  a  material adverse change in the Borrower or the
          Guarantor,

     2.e. the  Borrower  shall disaffirm or disavow any of its obligations under
          the  Loan  Documents  or  the  Guarantor  shall  disaffirm  any of its
          obligations  hereunder,

     2.f. the  Borrower or the Guarantor shall admit in writing its inability to
          pay  its  debts  as  they  become  due,

     2.g. any  indebtedness  (direct  or  contingent)  for borrowed money of the
          Borrower  or  the  Guarantor  shall  not  be paid as and when the same
          becomes  due  and  payable,  including any applicable grace period, or

     2.h. the  commencement  of any bankruptcy, insolvency or similar proceeding
          by  or  against  the  Borrower  or  the  Guarantor.

     This  is  a  guaranty  of payment rather than of collection; this is also a
     continuing  guaranty and all liabilities to which this Guaranty applies, or
     may apply, under the terms hereof shall be presumed to have been created in
     reliance  hereon.

     2.2  Nature  of  Obligations.  The  obligations  of  the  Guarantor to make
          -----------------------
     payments  to  RZB  hereunder are direct and primary obligations which shall
     not  be  discharged  for any reason until RZB has been indefeasibly paid in
     full.  Without limiting the generality of the foregoing, the obligations of
     the  Guarantor  hereunder  shall  remain  in  force  irrespective  of:

     2.a. any  invalidity,  illegality or unenforceability of, or any defect in,
          any  of  the  Loan  Documents or Guaranteed Obligations or any defense
          which  the  Borrower  may  have  with  respect  thereto,

     2.b. the existence or absence of any legal action to enforce the Guaranteed
          Obligations  or  the  Loan  Documents  or  any  security therefor, the
          issuance  of  any  judgment  therefor  or  the  execution  of any such
          judgment,  or

     2.c. any  other  circumstance  which  might  otherwise constitute a defense
          available  to  or  discharge  of,  a  guarantor or surety of any type.

     This guaranty is several and independent of, and may be enforced regardless
     of,  any  other  obligation  (direct or contingent) of the Guarantor or any
     other  "Person"  (such  term to include any person or legal or governmental
     entity,  association,  agency  or  instrumentality)  with  respect  to  the
     Guaranteed  Obligations.

     2.3  Payments.  All  payments  by  the Guarantor hereunder shall be made to
          --------
     RZB  without  set-off,  recoupment, deduction or counterclaim at its office
     set  forth below (or as RZB may otherwise direct) in lawful currency of the
     United  States  of  America  and  in  immediately  available funds. Without
     limiting the foregoing, all payments hereunder shall be made free and clear
     of,  and  without deduction for, any present or future withholding or other
     taxes  or  duties,  including  stamp duties, or other charges of any nature
     imposed on such payments by or on behalf of any government or any political
     subdivision  or  agency  thereof  or  therein. If any such taxes, duties or
     charges  are  so  levied or imposed on any such payment, the Guarantor will
     make  additional  payments  in such amounts as may be necessary so that the
     net  amount  received by RZB, after deduction for or on account of all such
     taxes,  duties or charges, will be equal to the amount provided for herein.
     The  Guarantor  shall  furnish promptly to RZB official receipts evidencing
     the  payment  of  any  such taxes, duties or charges paid by the Guarantor.

                                      -1-
<PAGE>
3.   SPECIAL  AGREEMENTS  OF  GUARANTOR

     3.1  Subordination.  Subject to the next following sentence of this Section
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     3.1:

     3.a. all  claims of the Guarantor against the Borrower shall be subject and
          subordinate  to the prior payment to RZB of all Guaranteed Obligations
          and  all  obligations  of  the  Guarantor  hereunder,  and

     3.b. the Guarantor shall not be entitled to receive any payment or exercise
          any  set-off  in respect of any such claim and, to the extent any such
          payment  is  received  (whether  directly,  by  way  of  dividend  in
          bankruptcy,  set-off  or  otherwise),  the  Guarantor  will  forthwith
          deliver  the  same (or the value thereof) to RZB in precisely the form
          received  (except  for endorsement or assignment where necessary), for
          application to the Guaranteed Obligations and, until so delivered, the
          same  shall  be  held  in  trust  as  the  property  of  RZB.

     Notwithstanding the foregoing, except as provided in Section 3.2, until the
     occurrence  of  any default or event of default under the Loan Documents or
     this  Guaranty,  or  any  demand  for  payment  of  any  of  the Guaranteed
     Obligations, the Guarantor may receive and retain payment in respect of any
     obligation  owed  to it by the Borrower. If the Guarantor fails to make any
     necessary  endorsement  or assignment of any instrument of payment to which
     RZB  is  entitled,  RZB  and  any  of  its officers or employees are hereby
     irrevocably  authorized  to  make  the  same  on  behalf  of the Guarantor.

     3.2  No  Subrogation.  The Guarantor hereby waives any right of subrogation
          ---------------
     that  it  may have with respect to any payment that it may have made to RZB
     hereunder.

     3.3  No  Contribution.  The Guarantor agrees that it shall have no legal or
          ----------------
     equitable  right  or  claim  (by  way  of  indemnification, contribution or
     otherwise)  against  any  subsidiary or affiliate of RZB which has issued a
     guaranty  to  RZB  in  respect  of  the  Guaranteed  Obligations.

     3.4  Waivers.  Except to the extent required by law which cannot be waived,
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     the  Guarantor  waives  notice of acceptance of this Guaranty and notice of
     any  liability  to  which  it may apply, and waives diligence, presentment,
     demand  for  payment, protest, notice of dishonor or nonpayment of any such
     liabilities,  suit  or  taking  other  action  or  making any demand by RZB
     against,  and  any other notice to, any party liable thereon (including the
     Guarantor).  The Guarantor agrees that RZB may at any time and from time to
     time,  upon  or  without  any  terms or conditions and in whole or in part:

     3.a. change the manner, place or terms of, and/or change or extend the time
          of payments of, renew or alter, any of the Guaranteed Obligations, any
          security therefor, or any liability incurred directly or indirectly in
          respect  thereof,  and  this  Guaranty  shall  apply to the Guaranteed
          Obligations  so  changed,  extended,  renewed  or  altered,

     3.b. fail  to  record,  perfect  or  protect,  or  sell, exchange, release,
          surrender,  realize  upon  or otherwise deal with in any manner and in
          any  order,  any property or Person whatsoever at any time securing or
          guaranteeing  the Guaranteed Obligations or any liabilities (including
          any  of  those  hereunder)  incurred directly or indirectly in respect
          thereof  or  hereof,  and/or  any  offset  thereagainst,

     3.c. exercise or refrain from exercising any rights against the Borrower or
          any other Person (including any guarantor) or otherwise act or refrain
          from  acting,

     3.d. settle,  release  or compromise any of the Guaranteed Obligations, any
          security  therefor or any liability (including any of those hereunder)
          incurred  directly or indirectly in respect thereof or hereof, and may
          subordinate  the  payment  of  all  or  any  part  of  the  Guaranteed
          Obligations to the payment of any other liability (whether due or not)
          of  the  Borrower  to  the  creditors of the Borrower (including RZB),

     3.e. apply  any  sums  by  whomsoever  paid  or  howsoever  realized to any
          liability  or  liabilities  of  the Borrower to RZB regardless of what
          liability  or liabilities of the Borrower remain unpaid, provided that
          payments  by  the Guarantor pursuant to this Guaranty shall be applied
          to  its obligations hereunder, but in such order as RZB may determine,

     3.f. consent  to  or waive any breach of or act, omission or default under,
          or  modify  or  amend  any  provision  of,  the Loan Documents, and/or

     3.g. increase  the  amount  of indebtedness of the Borrower to RZB, whether
          under  the  Loan  Documents  or  otherwise.

     It  is  understood and agreed that RZB may take any such action without the
     consent  of,  or notice to, the Guarantor, without incurring responsibility
     to the Guarantor, and without impairing or releasing the obligations of the
     Guarantor  hereunder.

     3.5  Amounts  Reclaimed.  If  claim  is  made  upon  RZB  for  repayment or
          ------------------
     recovery  of  any  amount  received  on  account  of  any of the Guaranteed
     Obligations  and  RZB  repays  all  or  part  of  said amount by reason of:

     3.a. any  judgment,  decree  or  order of any court, administrative body or
          trustee  in  bankruptcy  (or  other  Person  acting  on  behalf of the
          Borrower  or  its  estate)  or,

     3.b. any  settlement  or  compromise of any such claim effected by RZB with
          any  such  claimant  (including  the  Borrower),  or

     c.   any  other  reason,

     then,  and  in any such event, the Guarantor agrees that any such repayment
     (by reason of any such judgment, decree, order, settlement or compromise or
     otherwise)  shall  be  binding  upon  the  Guarantor,  notwithstanding  any
     cancellation  of  the  Loan  Documents  or this Guaranty, and the Guarantor
     shall  be  and  remain  liable to RZB hereunder for the amount so repaid or
     recovered  to  the same extent as if such amount had never been received by
     RZB.

                                      -2-
<PAGE>
     3.6  Interest.  If  the  Guarantor  fails  to  pay  when due any obligation
          --------
     hereunder, then, to the extent permitted by law, such obligation shall bear
     interest,  payable  on  demand,  from  the due date thereof until paid at a
     fluctuating  rate  per annum equal to 2% in excess of the Base Lending Rate
     (as  hereinafter  defined); provided that no such additional interest shall
     be  payable  in  respect  of  any  such  obligation  on  which  interest is
     simultaneously  accruing  pursuant  to  the  Loan Documents. The term "Base
                                                                            ----
     Lending  Rate"  means, for any day, the higher of (i) the rate announced by
     -------------
     The  Chase  Manhattan  Bank (the "Bank") from time to time at its principal
     office in New York, New York as its prime rate for domestic (United States)
     commercial  loans in effect on such day and (ii) the Federal Funds Rate (as
     hereinafter  defined)  in  effect on such day plus 1/2%. (Such Base Lending
     Rate  is not necessarily intended to be the lowest rate of interest charged
     by  the  Bank  in connection with extensions of credit.) Each change in the
     Base  Lending  Rate  shall result in a corresponding change in the interest
     rate  and  such  change  shall  be  effective on the effective date of such
     change  in  the  Base  Lending  Rate.

     The  term  "Federal  Funds  Rate" means, for any day, the overnight federal
                 --------------------
     funds  rate in New York City, as published for such day (or, if such day is
     not  a New York Business Day, for the next preceding New York Business Day)
     in  the  Federal  Reserve  Statistical  Release H.15 (519) or any successor
     publication, or if such rate is not so published for any day which is a New
     York  Business Day, the average of the quotations for such day on overnight
     federal  funds  transactions  in  New York City received by RZB or the Bank
     from  three federal funds brokers of recognized standing selected by RZB or
     the  Bank.

     3.7  The  Borrower,  etc.  The Guarantor will not cease to own (directly or
          -------------------
     indirectly),  free and clear of all liens and encumbrances, the interest in
     the  Borrower or any other Loan Party (as defined in the Line Letter) which
     it  presently  owns  (if  any) and will not agree to sell or subject to any
     lien,  encumbrance or any other security device such interest at any future
     time,  until  the  Loan  Documents  are  terminated  and  all  Guaranteed
     Obligations  and  all  obligations  of  the Guarantor hereunder are paid in
     full.

     3.8  Information.  The  Guarantor  will  promptly  furnish  to  RZB  such
          -----------
     information  regarding  its  and  the  Borrower's  business,  affairs  and
     financial  condition  as  RZB  may  from  time  to time reasonably request.

     3.9  Secured  Obligations.  The  Guarantor shall not grant, create, assume,
          --------------------
     incur or suffer to exist a security interest in or lien or encumbrance upon
     any  of  its  property  for  the purpose of securing the obligations of the
     Borrower  and/or  itself  to any other Person unless such Person shall have
     entered  into  an  intercreditor  agreement  with RZB in form and substance
     satisfactory  to  RZB.

4.   REPRESENTATIONS,  WARRANTIES  AND  AGREEMENTS

     In  order  to  induce  RZB  to  agree  to  the Loan Documents, to extend or
     continue  the  credit  provided  thereby  and  to accept this Guaranty, the
     Guarantor  makes  the  following representations, warranties and agreements
     which  shall  survive  the  execution  and  delivery  of  this  Guaranty:

     4.1  Organizational  Status  and  Power.  The  Guarantor:
          ----------------------------------

     4.a. is, and will continue to be, duly organized and validly existing under
          the  law  of  the  jurisdiction  of  its organization, as indicated in
          Section  1,  and

     4.b. has  the  power  to  own  its  assets,  to conduct its business as now
          conducted  and  to  enter  into  and  perform  the  provisions of this
          Guaranty.

     4.2  Legality.  The  entering into and performance by the Guarantor of this
          --------
     Guaranty:

     4.a. have  been  duly authorized by all necessary corporate and stockholder
          action  or  other action required by its organizational documents, and

     4.b. do  not  contravene any existing law or any legal order applicable to,
          or  license  or  permit granted to, the Guarantor, or any agreement or
          instrument  to which the Guarantor is a party or to which it or any of
          its  assets  is  subject  or  any  provision  of  the  Guarantor's
          organizational  documents.

     This  Guaranty is the legal, valid and binding obligation of the Guarantor,
     enforceable  in  accordance  with  its  terms.

     4.3  Governmental  Approvals.  Neither  any  action  by  or  with  any
          -----------------------
     governmental  or  public  body or authority (including, without limitation,
     any  exchange  control  or monetary authority), or any subdivision thereof,
     nor  any  other legal formality is required in connection with the entering
     into,  performance  or  enforcement  of  this  Guaranty  (collectively,
     "Governmental  Approvals"),  except  such as has been obtained or taken and
     with  respect  to  which  a copy or other satisfactory evidence thereof has
     been  furnished  to  RZB.  The  Guarantor  will  maintain  all  requisite
     Governmental  Approvals  until  the  Loan  Documents are terminated and the
     Guaranteed  Obligations  and  all  of its obligations hereunder are paid in
     full.

     4.4  Financial Condition.  The most recent year-end financial statements of
          -------------------
     the  Guarantor furnished to RZB prior to the date hereof have been prepared
     in  accordance  with  generally accepted accounting principles consistently
     applied  and  fairly  present  the  financial  condition and the results of
     operations  of  the Guarantor as at the end of and for the reporting period
     covered  thereby.  There  are  no  material  liabilities  or  any  material
     unrealized or anticipated losses from unfavorable commitments which are not
     disclosed  in such financial statements. There has been no material adverse
     change  in the operations, business or financial condition of the Guarantor
     from  that  set  forth in such financial statements; and there are no legal
     proceedings  pending  or,  to  the  knowledge  of the Guarantor threatened,
     against  or  affecting  the  Guarantor  which might (individually or in the
     aggregate)  result  in  such  a  material  adverse  change.

     4.5  Investment  Company  Act.  The  Guarantor  is not required to register
          ------------------------
     under  the  Investment Company Act of 1940, as amended (the "Act"), and the
     entering  into  of this Guaranty and the performance thereof do not violate
     any  provision  of  the  Act.

     On  each  anniversary  of  the  date of this Agreement, the Guarantor shall
     deliver  to  RZB  a  certificate  of an authorized officer of the Guarantor
     wherein  the  Guarantor  shall  reaffirm  to  RZB  the continuing truth and
     validity  of  the representations and warranties set forth in the foregoing
     Section  4.  The  failure  of the Guarantor to deliver and/or RZB to demand
     such  delivery  of  the  foregoing  certificate  shall  in no way affect or
     invalidate  the continuing nature of the representations and warranties set
     forth  in  the  foregoing  Section  4.

                                      -3-
<PAGE>
5.   MISCELLANEOUS

     5.1  Payment  of  Expenses.  The  Guarantor agrees to pay all out-of-pocket
          ---------------------
     costs and expenses of RZB arising in connection with its administration and
     enforcement  of,  or  preservation  of  its  rights  under,  this  Guaranty
     (including, without limitation, the reasonable fees and expenses of counsel
     for  RZB),  and  all stamp taxes (including interest and penalties, if any)
     which  may be payable in respect of this Guaranty or of any modification of
     this  Guaranty.

     5.2  Modification.  This  Guaranty  may  be  modified  or waived only by an
          ------------
     instrument  in  writing signed by the party against whom enforcement of the
     modification  or  waiver  is  sought.

     5.3  THIS  GUARANTY AND THE RIGHTS AND OBLIGATIONS OF THE PARTIES HEREUNDER
     SHALL  BE  GOVERNED  BY,  AND  CONSTRUED IN ACCORDANCE WITH, THE LAW OF THE
     STATE  OF  NEW  YORK  (WITHOUT  REGARD  TO PRINCIPLES OF CONFLICTS OF LAW).

     5.4  Notices.  Communications  given  to  any party in connection with this
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     Guaranty  shall  be  in  English and in writing and shall be effective when
     delivered  at  its  address set forth herein, as the same may be changed by
     written  notice  to  the  other party. Written communications may be in any
     form  of  writing  howsoever  transmitted.

     5.5  Waiver.  RZB's  rights,  powers,  privileges  and  remedies under this
          ------
     Guaranty  or  applicable law are cumulative and not exclusive and shall not
     be  waived,  precluded  or  limited by any failure or delay in the exercise
     thereof or by RZB's exercise, or partial exercise, of any thereof or by any
     course  of dealing between the Guarantor and RZB. No notice to or demand on
     the  Guarantor  in  any  case  shall  entitle the Guarantor to any other or
     further  notice or demand in similar or other circumstances or constitute a
     waiver  of  the  right  of  RZB  to  any  other  or  further  action in any
     circumstance  without  notice  or  demand.

     5.6  Descriptive  Headings.  The descriptive headings used in this Guaranty
          ---------------------
     are  for  convenience only and shall not be deemed to affect the meaning or
     construction  of  any  provision  hereof.

     5.7  Benefit  of  Guaranty.  This  Guaranty  shall  be  binding  upon  the
          ---------------------
     Guarantor and its successors and assigns and shall inure to the benefit of,
     and  be  enforceable  by,  RZB  and  its  successors  and  assigns  and, in
     particular, any holder or assignee from time to time of the Loan Documents;
     provided that the Guarantor may not assign any of its rights or obligations
     hereunder  without  the  prior  written  consent  of  RZB.

     5.8  Set-Off.  RZB is authorized at any time and from time to time, without
          -------
     notice  to  the  Guarantor  or  to  any other Person, any such notice being
     hereby expressly waived, to set off and apply any and all deposits (general
     or  special) and any other indebtedness at any time held or owing by RZB to
     or for the credit or the account of the Guarantor against and on account of
     the  obligations  of  the  Guarantor  under  this Guaranty, irrespective of
     whether  or  not RZB shall have made any demand hereunder or any demand for
     payment  of  any  Guaranteed  Obligation  and  although  said  obligations,
     liabilities  or  claims,  or any of them, shall be contingent or unmatured,
     and  the  Guarantor  hereby  grants  to RZB a security interest in all such
     deposits  and  indebtedness.

     5.9  Jurisdiction  and  Immunity.  The Guarantor represents and agrees that
          ---------------------------
     it  is  not entitled to, and to the extent it hereafter becomes so entitled
     hereby waives, any immunity, sovereign or otherwise, with respect to itself
     and  its  property  from jurisdiction, service, attachment (both before and
     after  judgment)  and  execution in legal proceedings wherever commenced to
     enforce  or  collect  upon  this  Guaranty.

     5.10  Survival.  The provisions of Sections 3.5, 5.1 and 5.11 shall survive
           --------
     the  termination  and cancellation of this Guaranty and, after cancellation
     and  return  to  the  Guarantor,  a  photocopy  hereof  may be submitted as
     evidence  of  such surviving obligations. Nothing herein shall preclude RZB
     from  establishing  such  obligations  by  other  means.

     5.11 WAIVER OF JURY TRIAL.  EACH OF THE GUARANTOR AND RZB HEREBY KNOWINGLY,
          --------------------
     VOLUNTARY  AND  INTENTIONALLY  WAIVES  ANY  AND ALL RIGHTS IT MAY HAVE TO A
     TRIAL  BY  JURY  IN  RESPECT OF ANY LITIGATION BASED ON, OR ARISING OUT OF,
     UNDER,  OR  IN  CONNECTION  WITH  THIS  GUARANTY  OR  ANY OTHER DOCUMENT OR
     AGREEMENT EXECUTED IN CONNECTION HEREWITH, OR ANY COURSE OF CONDUCT, COURSE
     OF  DEALING,  STATEMENTS  (WHETHER  VERBAL  OR  WRITTEN), OR ACTIONS OF THE
     GUARANTOR, THE BORROWER OR RZB. THIS PROVISION IS A MATERIAL INDUCEMENT FOR
     RZB'S  EXTENDING TO THE BORROWER THE CREDIT FACILITY TO WHICH THIS GUARANTY
     RELATES.

     5.12  Consent  to Jurisdiction.  The Guarantor hereby agrees that ANY LEGAL
           ------------------------
     ACTION OR PROCEEDING AGAINST THE GUARANTOR WITH RESPECT TO THIS GUARANTY OR
     ANY  LOAN DOCUMENT MAY BE BROUGHT IN THE COURTS OF THE STATE OF NEW YORK IN
     THE  CITY  OF  NEW YORK OR OF THE UNITED STATES OF AMERICA FOR THE SOUTHERN
     DISTRICT  OF  NEW  YORK,  as  RZB may elect, and, by execution and delivery
     hereof, the Guarantor accepts and consents to, for itself and in respect of
     its  property,  generally  and  unconditionally,  the  jurisdiction  of the
     aforesaid  courts  and  agrees  that  such jurisdiction shall be exclusive,
     unless  waived  by RZB in writing, with respect to any action or proceeding
     brought  by  it  against  RZB  and  any question relating to usury. Nothing
     herein  shall  limit  the  right  of  RZB  to bring proceedings against the
     Guarantor  in  the courts of any other jurisdiction. Service of process out
     of  any  such courts may be made by mailing copies thereof by registered or
     certified  mail,  postage  prepaid,  to  the  Guarantor  at its address for
     notices  as  specified  herein and will become effective 30 days after such
     mailing.  The  Guarantor  agrees  that  Sections  5-1401  and 5-1402 of the
     General  Obligations  Law  of  the  State  of  New York shall apply to this
     Guaranty  and  the  Loan  Documents and, to the maximum extent permitted by
     law,  waives  any  right  to  any  defense  of, or to dismiss any action or
     proceeding brought before said court on the basis of, forum non conveniens.
                                                           ----- --- ----------

                                      -4-
<PAGE>
IN  WITNESS  WHEREOF,  the Guarantor has caused this Guaranty to be executed and
delivered  by its duly authorized officer(s) as of the date first above written.

NAME OF GUARANTOR:

RIO VISTA ENERGY PARTNERS L.P.

By:  RIO VISTA GP LLC, general partner

     By: /s/ Richard Shore, Jr.
         -----------------------------
     Name: Richard  Shore,  Jr.
           ---------------------------
     Title: President
            --------------------------

ADDRESS OF GUARANTOR:

Rio Vista Operating Partnership L.P.
820 Gessner Road
Houston, TX 77024

ACCEPTED AS OF THE DATE FIRST ABOVE WRITTEN:

RZB FINANCE LLC

By:  /s/ Pearl Geffers
     ---------------------------------
     Pearl Geffers

Title: First Vice President
        ------------------------------

By:  /s/  Griselda Alvizo
     ---------------------------------
     Griselda Alvizo

Title: Vice President
       -------------------------------

                                      -5-
<PAGE>GENERAL SECURITY AGREEMENT

In  consideration of loans, credit or other financial accommodations extended or
continued  from  time  to  time  to,  or  on  the guaranty, endorsement or other
assurance  of, the undersigned ("Obligor") by RZB Finance LLC (together with its
successors  and  assigns,  "RZB"),  Obligor  hereby  agrees  as  follows:

1.   Security  Interest.
     ------------------

     a.        To secure the full and punctual payment and performance of all of
          the Obligations (as hereinafter defined), Obligor hereby grants to RZB
          a continuing security interest in, and assigns and pledges to RZB, the
          Collateral  (as  hereinafter  defined).

     b.        "Obligations"  shall  mean  and  include  all  indebtedness,
          liabilities,  obligations,  covenants  and duties of Obligor to RZB or
          any  Affiliate of RZB (including those which RZB or such Affiliate may
          have  acquired  from  others)  of  every kind, nature and description,
          direct  or  indirect,  absolute  or  contingent,  due  or  not  due,
          contractual  or  tortious,  liquidated  or  unliquidated,  arising  by
          operation  of law or otherwise, now existing or hereafter arising, and
          whether  or not evidenced by any note or other instrument or agreement
          and  whether  or  not  for  the  payment  of money, including, but not
          limited  to,  indebtedness, obligations and liabilities to RZB or such
          Affiliate  of  Obligor  as  a  member  of  any partnership, syndicate,
          association  or  other  group.

     c.        Affiliate  and  certain  other  terms  used herein are defined in
          Section  15  hereof.

     d.   As used herein, the term "Collateral" means the property described
          opposite  the  box(es)  checked  below  together  with  the  property
          described  in  Section  1(f)  below:

     [X]  A.   All Personal Property.  All of the personal property and fixtures
of the Obligor wherever located and whether now owned or in existence or
hereafter acquired or created, of every kind and description, tangible or
intangible, including without limitation all inventory (including, without
limitation, inventory as defined in Section 1(d)(C) hereof), goods and
accessions thereto, equipment and accessions thereto, farm products, documents,
chattel paper (whether tangible or electronic), accounts (including, without
limitation, accounts as defined in Section 1(d)(D) hereof), contract rights,
securities and other investment property, general intangibles, tax refund
claims, patents, trademarks,  intellectual property,  payment intangibles,
supporting obligations, instruments, promissory notes, letters of credit and
proceeds thereof, advices of credit, letter-of-credit rights (whether or not the
letter of credit is evidenced by a writing), commercial tort claims, credits,
deposits, cash, deposit accounts (general or special), and certificates of
deposit.  Each of such terms which is defined in the New York Uniform Commercial
Code as in effect from time to time shall have the meaning ascribed thereto
therein when used in this Agreement.

     [ ]  B.   Equipment.  Equipment (of any nature and description), now owned
or hereafter acquired and wherever located, employed in the operation of the
Obligor's business, and all proceeds thereof and products of such equipment in
any form whatsoever.  As used herein, the term "equipment" shall also mean and
include all spare parts therefor, all present and future additions, attachments
and accessions thereto, all substitutions therefor and replacements thereof.
Nothing herein shall be construed as giving a right to the Obligor to sell any
equipment which is the subject of this Agreement.

     [ ]  C.   Inventory.  All of the inventory of the Obligor, of every type or
description, now owned or hereafter acquired and wherever located, whether raw,
in process or finished, all goods usable in processing the same and all
documents, documents of title and receipts covering any inventory (hereinafter,
referred to as "inventory"), and all proceeds thereof and products of such
inventory in any form whatsoever, including but not limited to accounts and
chattel paper (whether tangible or electronic) and cash proceeds.

     [ ]  D.   Accounts and Chattel Paper.  All of the Obligor's present and
future accounts (including, without limitation, health-care-insurance
receivables), contract rights, letters of credit, letter-of-

                                      -1-
<PAGE>
credit rights, general intangibles, tax refund claims, payment intangibles,
software, supporting obligations, instruments, promissory notes, and chattel
paper (whether tangible or electronic) and all other rights to the payment of
money, whether or not arising out of the sale (or lease) of goods or services
(herein referred to in the plural as "accounts" and in the singular as
"account"), all proceeds thereof and all liens, securities, guarantees,
remedies, and privileges pertaining thereto, together with all rights and liens
of the Obligor in and to such goods, including returned or repossessed goods,
and all rights and property of any kind forming the subject matter of any of the
accounts, including the right of stoppage in transit.

     [ ]  E.   Other.

     See Schedule A annexed hereto and made a part hereof.

If no box is checked, Clause A (All Personal Property) shall be deemed
applicable for all purposes of this Agreement.  If the Clause A box is checked,
checking also the Clause B and/or Clause C and/or Clause D and/or Clause E
box(es) is not intended, and shall not be construed, to limit the generality or
legal effect of the description contained in Clause A.

     e.   (i)    If the Obligor shall at any time acquire a commercial tort
claim, as defined in Article 9 of the Uniform Commercial Code as in effect in
the State of New York ("NY UCC Article 9"), which the Obligor reasonably
believes based upon then-current information is likely to result in a judgment
in favor of the Obligor in excess of $25,000, the Obligor shall promptly notify
RZB in a writing signed by the Obligor of the brief details thereof and grant to
RZB in such writing a security interest therein and in the proceeds thereof, all
upon the terms of this Agreement, with such writing to be in form and substance
reasonably satisfactory to RZB.

          (ii)   RZB may at any time and from time to time file financing
statements, continuation statements and amendments thereto that describe the
Collateral as all assets of the Obligor or words of similar effect and which
contain any other information required by NY UCC Article 9 or revised Article 9
of the Uniform Commercial Code in the form or substantially in the form approved
in 1998 by the American Law Institute and the National Conference of
Commissioners on Uniform State Laws ("Revised Article 9") as adopted in any
other jurisdiction (including Part 5 thereof) for the sufficiency or filing
office  acceptance of any financing statement, continuation statement or
amendment, including whether the Obligor is an organization, the type of
organization and any organization identification number issued to the Obligor.
The Obligor agrees to furnish any such information to RZB  promptly upon
request.  Any such financing statements, continuation statements or amendments
may be signed by RZB on behalf of the Obligor and may be filed at any time with
or without any signature of the Obligor or RZB in any jurisdiction whether or
not NY UCC Article 9 or Revised Article 9 is then in effect in that
jurisdiction.

          (iii)  The Obligor shall at any time and from time to time, whether or
not NY UCC Article 9 or Revised Article 9 is in effect in any particular
jurisdiction, take such steps as RZB may request for RZB to (i) obtain an
acknowledgment, in form and substance satisfactory to RZB, of any bailee having
possession of any of the Collateral that the bailee holds such Collateral for
RZB, (ii) obtain "control" of any investment property, deposit accounts,
letter-of-credit rights or electronic chattel paper (as such terms are defined
in NY UCC Article 9 with corresponding provisions in Sections 9-104, 9-105,
9-106 and 9-107, relating to what constitutes "control" for such items of
Collateral), with any agreements establishing control to be in form and
substance satisfactory to RZB, and (iii) otherwise insure the continued
perfection and priority of RZB's security interest in any of the Collateral and
of the preservation of its rights therein, whether in anticipation of or
following the effectiveness of NY UCC Article 9 in New York or Revised Article 9
in any other jurisdiction.

f.   Any and all deposits or other sums at any time credited by or due from RZB
to the Obligor; and any and all monies, securities and other property of the
Obligor, and the proceeds thereof now or hereafter held or received by or in
transit to RZB from or for the Obligor, whether for safekeeping, custody,
pledge, transmission, collection or otherwise, shall at all times constitute
security for any and all Obligations.

                                      -2-
<PAGE>
2.   Rank  and  Perfection  of  Security  Interest.

     a.        Obligor  will  not  create  or  permit  to exist, nor shall there
          exist, any security interest in, lien, attachment, levy or encumbrance
          upon,  or  assignment or pledge as security of, any of the Collateral,
          except  the  security  interest  of  and  assignment and pledge to RZB
          hereunder  and  Permitted  Liens.

     b.        (i)    Obligor  will  from time to time, at its expense, take all
          action  requested  by  RZB, or which may be necessary or desirable, to
          perfect,  continue,  evidence,  preserve,  protect  or  validate  the
          security  interest  of  and  assignment and pledge to RZB hereunder to
          enable  RZB  to  exercise and enforce its rights hereunder, including,
          but  not limited to, (A) executing and delivering one or more notices,
          financing statements, agreements or other writings, and (B) delivering
          to  RZB,  and stamping or otherwise marking, in such manner as RZB may
          specify, any and all chattel paper, instruments, letters and advice of
          credit and documents constituting part of the Collateral, in each case
          endorsed  or  accompanied by such instruments of assignment as RZB may
          specify.

                    (ii)  Obligor  hereby  authorizes  RZB,  at  its  option but
          without  any  obligation  so to do, to file Financing and continuation
          statements  and  amendments to financing statements, naming Obligor As
          debtor, with respect to any of the Collateral without the signature of
          Obligor,  and agrees that a carbon, photographic or other reproduction
          of  this  Agreement  or  of  a  financing statement is sufficient as a
          financing  statement.  Obligor shall pay the costs of any recording or
          filing  of  any  financing  or  continuation statements, or amendments
          therto,  concerning  the  Collateral.

     3.   Covenants.

     a.        Obligor  shall  at  all times:  (i) be the sole owner of each and
          every  item  of  Collateral,  (ii)  defend  the Collateral against the
          claims  and  demands  of all persons and (iii) in the case of tangible
          property  constituting  part  of the Collateral, (A) properly maintain
          and  keep  in  good  order  and repair such property and (B) keep such
          property  fully  insured  with responsible companies acceptable to RZB
          against such risks as such Collateral may be subject to, or as RZB may
          request,  under policies containing loss payable clauses naming RZB as
          loss  payee  as  its  interests  may  appear and otherwise in form and
          substance  satisfactory  to  RZB, and providing that: (1) all proceeds
          thereof  shall  be  payable  to  RZB,  (2) such insurance shall not be
          affected  by  any  act  or  neglect  of  Obligor or other owner of the
          property  described  in  such  policy,  and  (3)  such policy and loss
          payable  clause  may not be cancelled or amended except upon ten days'
          prior  written  notice  to  RZB.

     b.        Obligor  will  comply  with  the  requirements  of  all  leases,
          mortgages  and  other  instruments  relating  to  premises  where  any
          Collateral  is  located.

     c.        Obligor  will  not  sell  or  otherwise  dispose  of  any  of the
          Collateral,  except  that,  if  the  same constitute Collateral, until
          notice  terminating  such  authority  is  given by RZB to Obligor, (i)
          accounts  may  be  collected  in  the  ordinary  course of business as
          heretofore  conducted  and (ii) inventory or farm products may be sold
          in  the  ordinary  course  of  business  as  heretofore  conducted.

     d.        Obligor  will give RZB not less than 30 days prior written notice
          of  (i)  any  change in (A) its name, identity or corporate structure,
          (B)  the  location of its chief executive office or any other place of
          business,  or  (C)  the location of any of the Collateral or its books
          and  records  concerning  any  accounts, (ii) the location of each new
          place  of  business  opened by Obligor, and (iii) each new location of
          any  Collateral.  Obligor  will  give RZB prompt notice of any loss or
          depreciation  in  the  value  of  any  of the Collateral. Set forth on
          Schedule  A annexed hereto are all trade names or trade styles used by
          Obligor,  the  location  of  Obligor's  chief  executive  office,  all
          locations  of  Collateral  and  all  locations  of Obligor's books and
          records.

     e.        At  any  time  and  from  time  to time (i) RZB may and is hereby
          authorized  to  transfer into or register in the name of itself or its
          nominee any instruments, investment property or documents constituting
          a  part  of  the  Collateral  without  notice to Obligor, (ii) RZB may
          receive  and  retain  all  Distributions  (as  hereinafter  defined in
          Section  15),  (iii) Obligor will permit representatives of RZB during
          normal  business  hours  to inspect its premises and books and records
          pertaining  to  the

                                      -3-
<PAGE>
     Collateral and make extracts from and copies of such books and records, and
     (iv)  upon  request,  Obligor will enter into warehousing, lockbox or other
     custodial  arrangements  satisfactory  to  RZB.

     f.        If  any Collateral is at any time in the possession or control of
          any  warehouseman,  bailee  or  any of Obligor's agents or processors,
          Obligor  shall,  and  RZB  shall  also  have the right to, notify such
          warehouseman,  bailee,  agent  or  processor of the security interests
          created  hereby and obtain the agreement of all such persons that they
          hold  and  will  hold possession of such Collateral for the benefit of
          RZB  and  deliver  the  same  at  the direction of RZB without further
          consent  of  the  Obligor.

     g.        Obligor  shall  keep full and accurate books and records relating
          to  the Collateral, and stamp or otherwise mark such books and records
          in  such  manner as RZB may reasonably require in order to reflect the
          security  interest  granted  hereby.

     h.        Obligor will immediately deliver and pledge to RZB or RZB's agent
          each  instrument,  now  owned  or  hereafter  acquired,  appropriately
          endorsed  to  RZB  or  RZB's  agent.

     i.        Obligor  shall use its best efforts to cause to be collected from
          its  account  debtors and other obligors, as and when due, any and all
          amounts  owing  under  or  on  account  of  each account, each general
          intangible,  each payment intangible, each supporting obligation, each
          right  to  payment  of  money,  each chattel paper and each instrument
          (including,  without  limitation, all of the foregoing items which are
          delinquent,  such  delinquent items to be collected in accordance with
          lawful collection procedures) and apply forthwith upon receipt thereof
          all  such  amounts  as  are so collected to the outstanding balance of
          such  items.  Upon  RZB's  request  at  any  time, any such amounts so
          collected  by  Obligor shall be promptly remitted to RZB, in precisely
          the  form  received (except for endorsement by Obligor when required),
          and  until  so  remitted to RZB, shall be held by Obligor in trust for
          RZB,  and  shall  not  be  commingled  with other funds or property of
          Obligor,  and  RZB  shall  be  entitled  to  apply such amounts to the
          Obligations  in  such  manner  as  RZB  in  its  sole discretion shall
          determine. Obligor will not renew or extend the time of payment of, or
          consent  or  agree to any reduction of the amount payable with respect
          to,  any  account  or  other  item  mentioned  above in this paragraph
          without the written consent of RZB. The costs and expenses (including,
          without  limitation,  attorneys' fees) of collection, whether incurred
          by  Obligor  or  RZB,  shall  be  borne  by  Obligor.

     j.        Upon  request  by  RZB, Obligor will promptly notify (and Obligor
          hereby  authorizes RZB so to notify) each account debtor or obligor in
          respect  of  any  account,  general  intangible,  payment  intangible,
          supporting  obligation,  right  to  payment of money, chattel paper or
          instrument  that  such  Collateral has been assigned to RZB hereunder,
          and  that  any  payments  due  or  to  become  due  in respect of such
          Collateral  are  to  be  made  directly  to  RZB  or  its  designee.

     k.        Obligor  will,  promptly  upon  request,  provide  to  RZB  all
          information  and  evidence  it  may  reasonably request concerning the
          Collateral,  and  in particular the accounts, to enable RZB to enforce
          the  provisions  of  this  Agreement.

     4.   General  Authority.  Obligor  hereby irrevocably appoints RZB its true
          ------------------
     and  lawful  attorney,  with  full  power  of  substitution, in the name of
     Obligor,  RZB,  or  otherwise,  for the sole use and benefit of RZB, but at
     Obligor's  expense, to the extent permitted by law to exercise, at any time
     and  from  time  to time while an Event of Default (as hereinafter defined)
     exists,  all  or  any of the following powers with respect to all or any of
     the  Collateral:

     a.        to demand, sue for, collect, receive and give acquittance for any
          and  all  monies  due  or  to become due thereon or by virtue thereof,

     b.        to  settle,  compromise, compound, prosecute or defend any action
          or  proceeding  with  respect  thereto,

     c.        to  take  any action or do any thing which Obligor is required to
          do  hereunder,

     d.        to  extend  the time of payment of any or all thereof and to make
          any  allowance  and  other  adjustments  with  reference  thereto, and

                                      -4-
<PAGE>
     e.        to  do  all  other acts and things necessary and advisable in the
          sole  discretion  of  RZB  to  carry  out  and enforce this Agreement.

     5.   Events  of  Default.  Without  limiting  the  right  of  RZB to demand
          -------------------
     payment  of  any  or  all  of  the  Obligations  at  any  time  in its sole
     discretion,  it shall be an Event of Default if any of the following events
     shall  occur:  (i)  default  in payment of any of the Obligations when due,
     whether  on  demand  or  otherwise; or (ii) the occurrence of any "Event of
     Default"  or "default" as defined or specified in any agreement, instrument
     or  document  evidencing  or  providing for the Obligations or any guaranty
     thereof.

     6.   Remedies  upon  Event  of  Default  Rights.  Upon the occurrence of an
          ------------------------------------------
     Event  of  Default  and  at  any  time  or  from  time  to time thereafter:

     a.        RZB  may  declare,  by  notice  to  Obligor,  any  and all of the
          Obligations  immediately  due  and  payable,  without  any  other
          presentment,  demand,  protest  or notice of any kind, anything in any
          other  agreement  to  the contrary notwithstanding, and in the case of
          any  bankruptcy,  insolvency or similar proceeding relating to Obligor
          or its property, all of the Obligations shall automatically become due
          and payable (provided, however, that the foregoing shall not be deemed
          to  limit or impair in any way whatsoever the absolute right of RZB to
          demand  payment of the Obligations at any time in its sole discretion,
          to  the  extent  the  agreements  and  instruments  pertaining to such
          Obligations  provide  for  such  demand);

     b.        RZB shall have no obligation to make further loans, extensions of
          credit  or  other financial accommodations to or on behalf of Obligor,
          anything  in  any  other  agreement  to  the  contrary notwithstanding
          (provided, however, that the foregoing shall not be deemed to limit or
          impair  in  any way whatsoever the sole and absolute discretion of RZB
          to  make  or  refrain  from making such loans, extensions of credit or
          financial  accommodations to the extent the agreements and instruments
          pertaining  thereto  provide  for  such  discretion);

     c.        RZB  may  exercise  all  other  rights  to  which  it is entitled
          hereunder  or  under  applicable  law;

     d.        RZB  may  exercise  all  rights  of a secured party under the UCC
          (whether  or  not  in effect in the jurisdiction where such rights are
          exercised)  and,  in addition, RZB may sell the Collateral or any part
          thereof  at  public  or  private  sales,  for cash, upon credit or for
          future  delivery,  and  at  such  price  or  prices  as  RZB  may deem
          satisfactory. RZB may be the purchaser of any or all of the Collateral
          so  sold  at  any  public  sale  (or,  if  the Collateral is of a type
          customarily  sold  in a recognized market or is of a type which is the
          subject  of  widely  distributed  standard  price  quotations,  at any
          private  sale) and thereafter hold the same, absolutely, free from any
          right or claim of whatever kind. Obligor will execute and deliver such
          documents  and  take  such  other  action  as  RZB  deems necessary or
          advisable  in order that any such sales may be made in compliance with
          law.  Upon  any such sales RZB shall have the right to deliver, assign
          and  transfer  to  the  purchaser thereof the Collateral so sold. Each
          purchaser  at  any  such sales shall hold the Collateral so sold to it
          absolutely,  free  from any claim or right of whatever kind, including
          any  equity  or  right  of  redemption  of  Obligor, and to the extent
          permitted  by  law,  Obligor  hereby specifically waives all rights of
          redemption,  stay  or appraisal which it has or may have under any law
          now  existing  or  hereafter adopted. The notice (if any) of such sale
          required herein shall (i) in the case of a public sale, state the time
          and  place  fixed for such sale, and (ii) in the case of private sale,
          state  the  day  after  which  such  sale may be consummated. Any such
          public  sale  shall  be  held  at  such  time or times within ordinary
          business  hours  and  at  such  place  or places as RZB may fix in the
          notice  of such sale. Unless the Collateral is perishable or threatens
          to  decline  speedily  in  value or is of a type customarily sold on a
          recognized market, RZB will give Obligor reasonable notice of the time
          and  place  of  any  such  public  sale or of the time after which any
          private  sale or any other intended disposition thereof is to be made,
          and  Obligor  agrees  that  five (5) days prior notice shall be deemed
          reasonable  notice. At any such sale the Collateral may be sold in one
          lot  as  an entirety or in separate parcels, as RZB may determine. RZB
          shall  not  be  obligated  to  make any such sale pursuant to any such
          notice.  RZB  may without notice or publication, adjourn any public or
          private  sale  or  cause the same to be adjourned from time to time by
          announcement  at  the time and place fixed for the sale, and such sale
          may  be  made  at  any  time  or  place  to  which  the same may be so
          adjourned.  In  case  of  any  sale  of  all or any part of Collateral

                                      -5-
<PAGE>
          on  credit or for future delivery, the Collateral sold may be retained
          by  RZB  until the selling price is paid by the purchaser thereof, but
          RZB  shall  not  incur  any  liability  in case of the failure of such
          purchaser  to  take up and pay for the Collateral so sold and, in case
          of  any  such  failure,  such  Collateral  may again be sold upon like
          notice.  RZB, instead of exercising the power of sale herein conferred
          upon  it,  may  proceed  by  a  suit  or  suits at law or in equity to
          foreclose  the  security  interests  granted  herein  and  sell  the
          Collateral,  or  any  portion thereof, under a judgment or decree of a
          court  or  courts  of  competent  jurisdiction.

     e.        For  the  purposes  of  enforcing any and all rights and remedies
          under  this  Agreement,  RZB  may  (i) require Obligor to, and Obligor
          agrees  that  it  will,  at  its  expense and upon the request of RZB,
          forthwith  assemble  all  or any part of the Collateral as directed by
          RZB  and  make  it available at a place designated by RZB which is, in
          its  opinion,  reasonably convenient to RZB whether at the premises of
          Obligor  or otherwise, (ii) to the extent permitted by applicable law,
          enter, with or without process of law and without breach of the peace,
          any  premises  where  any  of the Collateral is or may be located, and
          without  charge  or  liability to it, seize and remove such Collateral
          from  such  premises, (iii) have access to and use Obligor's books and
          records  relating  to the Collateral and (iv) prior to the disposition
          of  the Collateral, store or transfer it without charge in or by means
          of  any  storage or transportation facility owned or leased by Obligor
          or  any  other person, corporation or other entity, process, repair or
          recondition  it  or otherwise prepare it for disposition in any manner
          and  to  the extent RZB deems appropriate and, in connection with such
          preparation  and  disposition, use without charge any trademark, trade
          name,  copyright,  patent  or  technical  process  used  by  Obligor.

     f.        If  the Collateral consists in whole or in part of instruments or
          other  investment property and RZB elects to sell or otherwise dispose
          of such instruments or other investment property, (i) Obligor will, if
          it  controls  the  issuer  of  such  instruments  or  other investment
          property,  or  it otherwise has the right to effect such registration,
          and  if  RZB  deems  such  registration  to  be  desirable, cause such
          instruments  or  other  investment property to be registered under the
          Securities  Act  of  1933,  as  amended,  and  take  all other action,
          including  but  not  limited  to  complying  with  the  "blue  sky" or
          securities  laws  of  the  several  states  and  delivering  to  RZB
          appropriate quantities of prospectuses, necessary or appropriate so as
          to  permit the public sale or other disposition thereof by RZB in such
          jurisdictions  as  RZB  may  select,  and  indemnify, in the form then
          customary,  all  persons who are underwriters, statutory or otherwise,
          of  such  instruments  or other investment property in connection with
          such  sale or disposition, such indemnity, to the extent applicable to
          RZB,  to  be  in  addition  to  that  afforded RZB under Section 10(c)
          hereof, and (ii) RZB may elect not to exercise its rights under clause
          (i) and in that event may, if in its judgment it shall be necessary or
          desirable  so  to do, restrict the number of prospective bidders so as
          to comply with the provisions of Section 5 of such Securities Act, and
          restrict  such  prospective  bidders to persons who will represent and
          agree  that  they  are  purchasing the instruments or other investment
          property in question for their own account for investment and not with
          a  view  to  the  distribution  or release of any thereof and who will
          further  agree  that  such  instruments  or  other investment property
          purchased  by  them may bear an appropriate restrictive legend to that
          effect.

     7.   Limitation  on  Duty of RZB in Respect of Collateral.  Beyond the safe
          ----------------------------------------------------
     custody  thereof,  RZB  shall  have  no  duty  as  to any Collateral in its
     possession  or  control  or  in  the  possession or control of any agent or
     bailee  or  as  to  any  income thereon or as to the preservation of rights
     against  prior parties or any other rights pertaining thereto. RZB shall be
     deemed to have exercised reasonable care in the custody and preservation of
     the  Collateral  in  its possession if the Collateral is accorded treatment
     substantially  equal  to  that which it accords its own property, and shall
     not  be  liable  or  responsible  for  any  loss  or  damage  to any of the
     Collateral, or for any diminution in value thereof, by reason of the act or
     omission  of  any  warehouseman,  carrier,  forwarding agency, consignee or
     other  agent  or  bailee  selected  by  RZB  in  good  faith.

     8.   Application of Proceeds.  Upon any demand for payment of any or all of
          -----------------------
     the  Obligations  or  upon the occurrence and during the continuance of any
     other  Event  of Default, the proceeds of any sale of, or other realization
     upon,  all  or  any  part  of the Collateral shall be applied by RZB in the
     following  order  of  priority:

                                      -6-
<PAGE>
     a.        to  payment  of  the  expenses of such sale or other realization,
          including  reasonable compensation to (and costs and disbursements of)
          agents and counsel for RZB, and all expenses, liabilities and advances
          incurred  or  made  by  RZB  in  connection  therewith,  and any other
          unreimbursed  expenses  for  which RZB is to be reimbursed pursuant to
          the  documents  or  instruments  evidencing  or  governing  any of the
          Obligations;

     b.        to  the payment of accrued but unpaid interest on the Obligations
          in  accordance  with  the provisions of any promissory note, letter of
          credit  reimbursement  agreement  or  other  agreement  or  instrument
          evidencing  any  of  the  Obligations;

     c.        to  the  payment  of  unpaid  principal  of  the  Obligations;

     d.        to  the  payment  of all other Obligations, until all Obligations
          shall  have  been  paid  in  full;  and

     e.        to  payment  to  Obligor  or  its  successors  or  assigns, or to
          whomsoever  may  be  entitled  thereto,  or  as  a  court of competent
          jurisdiction  may  direct,  of  any  surplus  then remaining from such
          proceeds.

     If,  upon  the  sale,  lease  or  other  disposition of the Collateral, the
     proceeds  thereof  are  insufficient  to  pay  all  amounts to which RZB is
     legally  entitled,  Obligor will remain liable for the deficiency, together
     with  interest  thereon  at the rate provided for post-maturity interest in
     the  agreements  and  instruments  evidencing  the  Obligations.

     9.   General  Representations,  Warranties  and Agreements.  Obligor hereby
          -----------------------------------------------------
     represents,  warrants  and  agrees  that:

     a.        The  execution,  delivery  and  performance of this Agreement are
          within  its  powers, corporate or otherwise, have been duly authorized
          by  all  required action and do not and will not contravene any law or
          any agreement or undertaking to which it is a party or by which it may
          in  any  way be bound or, if Obligor is a corporation, its certificate
          of  incorporation  or  by-laws.

     b.        Each  of  the  representations and warranties contained herein is
          true  and  correct  on  the  date  hereof  and  all other information,
          including  financial  statements  and projections, furnished to RZB at
          any  time  by  or  on  behalf  of Obligor was and will be complete and
          correct  in  all  respects  to the extent necessary for the purpose of
          presenting  the  subject  matter  thereof  fairly  to  RZB.

     c.        The  Obligor  is the sole owner of each of the accounts and other
          items  of  Collateral referred to in Section 3(i) above and no one has
          or claims to have any interest of any kind therein or thereto; each of
          the  debtors and other obligors named in or obligated under every such
          account  and  other  items  of  Collateral referred to in Section 3(i)
          above  is  indebted  to  the  Obligor  in  the amount and on the terms
          indicated  in  the  invoice  or other evidence of such account or such
          other  item  of  collateral and any schedule of accounts, each account
          and other item of collateral referred to in Section 3(i) above is bona
          fide  and arises out of the completed performance of labor or services
          or  the sale and delivery or lease of merchandise or both; and none of
          the  accounts or such other item of collateral is now, nor will at any
          time  in  the  future  become  contingent  upon the fulfillment of any
          contract  or  conditions  whatsoever,  nor  subject  to  any  defense,
          recoupment,  offset  or  counterclaim.

     10.  Expenses  of  Obligor's  Duties;  RZB's Rights to Perform on Obligor's
          ----------------------------------------------------------------------
     Behalf;  RZB's  Expenses  and  Indemnification.
     ----------------------------------------------

     a.        Obligor's  agreements  and duties hereunder shall be performed by
          it  at  its  sole  cost  and  expense.

     b.        If  Obligor  shall  fail  to  do  any  act  or thing which it has
          covenanted to do hereunder, RZB may (but shall not be obligated to) do
          the same or cause it to be done, either in its name or in the name and
          on behalf of Obligor, and Obligor hereby irrevocably authorizes RZB so
          to  act.

                                      -7-
<PAGE>
     c.        Obligor  agrees  to  reimburse  RZB  for  all costs and expenses,
          including  attorneys'  fees  and  disbursements,  incurred,  and  to
          indemnify  and hold RZB harmless from and against all losses suffered,
          by  RZB  in  connection with (i) RZB's exercise of any right or remedy
          granted to it hereunder, (ii) any claim and the prosecution or defense
          thereof  arising  out  of or in any way connected with this Agreement,
          and  (iii)  the  collection  or  enforcement  of  the  Obligations.

     d.        Amounts payable by Obligor under this Section 10 shall constitute
          Obligations  which  shall  be  payable  on  demand.

     11.  No  Waivers  of  Rights  Hereunder;  Rights  Cumulative.
          -------------------------------------------------------

     a.        No  delay  by RZB in exercising any right hereunder, or under any
          of the other Obligations, shall operate as a waiver thereof, nor shall
          any  single or partial exercise of any right preclude other or further
          exercises  thereof  or  the  exercise of any other right. No waiver or
          amendment  of  any  provision of this Agreement or of any of the other
          agreements,  instruments or documents evidencing the Obligations shall
          be enforceable against RZB unless it shall be in writing, be signed by
          RZB,  and  expressly  refer to the provision affected; any such waiver
          shall  be  limited  solely  to  the  specific  event  waived.

     b.        All rights granted to RZB hereunder shall be cumulative and shall
          be  supplementary  of and in addition to those granted or available to
          RZB  with respect to the other Obligations or under applicable law and
          nothing  herein  shall  be construed as limiting any such other right.

     12.  Assignment,  Participations.
          ---------------------------

     a.        RZB  may  assign  any  or all of the Obligations and may transfer
          therewith  any  or  all  of the Collateral therefor and the transferee
          shall  have the same rights with respect thereto as had RZB. Upon such
          transfer,  RZB  shall  be  released  from  all  responsibility for the
          Collateral  so  transferred.

     b.        RZB  may from time to time sell or otherwise grant participations
          in  any  of  the  Obligations  and any Collateral for the Obligations.
          Obligor  agrees  that each such holder of a participation may exercise
          any  and  all  rights  of banker's lien, set-off and counterclaim with
          respect  to  its  participation  in the Obligations as fully as though
          Obligor  were  directly  indebted to such holder in the amount of such
          participation.

     13.  Continuing  Agreement;  Termination.
          -----------------------------------

     a.        This Agreement shall be a continuing agreement and shall apply to
          all  present  and  future  Obligations,  notwithstanding  that  at any
          particular  time  all  of  the Obligations then outstanding shall have
          been  paid  in  full.

     b.        This  Agreement  shall  continue  in  full force and effect until
          written  notice  of  termination  shall  have  been  signed  by  RZB.

     14.  Governing  Law;  Jurisdiction;  Certain  Waivers.
          ------------------------------------------------

     a.        THIS AGREEMENT SHALL BE CONSTRUED IN ACCORDANCE WITH AND GOVERNED
          BY  THE LAWS OF THE STATE OF NEW YORK, EXCEPT AS OTHERWISE REQUIRED BY
          MANDATORY  PROVISIONS  OF  LAW.

     b.        OBLIGOR HEREBY AGREES THAT ANY LEGAL ACTION OR PROCEEDING AGAINST
          OBLIGOR WITH RESPECT TO THIS AGREEMENT MAY BE BROUGHT IN THE COURTS OF
          THE  STATE OF NEW YORK IN THE CITY OF NEW YORK OR OF THE UNITED STATES
          OF  AMERICA  FOR  THE  SOUTHERN DISTRICT OF NEW YORK AS RZB MAY ELECT,
          AND,  BY  EXECUTION  AND DELIVERY HEREOF, OBLIGOR ACCEPTS AND CONSENTS
          TO,  FOR  ITSELF  AND  IN  RESPECT  TO  ITS  PROPERTY,  GENERALLY  AND
          UNCONDITIONALLY,  THE  JURISDICTION OF THE AFORESAID COURTS AND AGREES
          THAT  SUCH  JURISDICTION  SHALL  BE EXCLUSIVE, UNLESS WAIVED BY RZB IN
          WRITING,  WITH  RESPECT  TO  ANY

                                      -8-
<PAGE>
          ACTION  OR  PROCEEDING BROUGHT BY IT AGAINST RZB. NOTHING HEREIN SHALL
          LIMIT  THE  RIGHT  OF  RZB TO BRING PROCEEDINGS AGAINST OBLIGOR IN THE
          COURTS  OF ANY OTHER JURISDICTION. OBLIGOR AGREES THAT SECTIONS 5-1401
          AND  5-1402  OF  THE  GENERAL OBLIGATIONS LAW OF THE STATE OF NEW YORK
          SHALL  APPLY TO THIS AGREEMENT AND, TO THE MAXIMUM EXTENT PERMITTED BY
          LAW,  WAIVES  ANY RIGHT TO STAY OR TO DISMISS ANY ACTION OR PROCEEDING
          BROUGHT  BEFORE  SAID  COURTS  ON  THE  BASIS OF FORUM NON CONVENIENS.
                                                           ----- --- ----------

     c.        Obligor  waives  personal  service  of  process and consents that
          service  of  process  upon  it  may be made by certified or registered
          mail,  return  receipt  requested,  directed to Obligor at its address
          last  specified  for  notices  hereunder, and service so made shall be
          deemed  completed  five days after the same shall have been so mailed.

     d.        EACH  OF  RZB  AND  OBLIGOR  HEREBY  KNOWINGLY,  VOLUNTARILY  AND
          INTENTIONALLY WAIVES ANY AND ALL RIGHTS IT MAY HAVE TO A TRIAL BY JURY
          IN  RESPECT OF ANY LITIGATION BASED ON, OR ARISING OUT OF, UNDER OR IN
          CONNECTION  WITH  THIS  AGREEMENT, OR ANY COURSE OF CONDUCT, COURSE OF
          DEALING,  STATEMENTS (WHETHER VERBAL OR WRITTEN) OR ACTIONS OF OBLIGOR
          OR  RZB.  THIS  PROVISION IS A MATERIAL INDUCEMENT FOR RZB'S EXTENDING
          CREDIT  TO  OBLIGOR.

     15.  Definitions.  As  used  herein:
          -----------

     a.        Except  as otherwise specifically defined or provided herein, all
          terms  defined  in  Article  1 or 9 of the New York Uniform Commercial
          Code  as  in effect on the date of this Agreement (other than the term
          "Collateral")  are  used  herein  with  the  meanings  therein  given.

     b.        The  following  terms  shall  have  the  indicated  meanings:

          "Affiliate"  of  RZB  shall  mean  a  corporation  that  directly  or
          indirectly  controls  or  is controlled by, or is under common control
          with,  RZB.

          "Distributions"  shall mean cash dividends and other distributions and
          interest  paid  in cash, in each case with respect to all instruments,
          investment  property  and  securities  constituting  part  of  the
          Collateral.

          "Guarantor"  shall  mean  any  maker,  drawer,  acceptor,  endorser,
          guarantor,  surety, accommodation party or other person liable upon or
          for  any  of  the  Obligations.

          "Permitted Liens" shall mean liens specifically consented to by RZB in
          writing, and liens of any other financial institution which is a party
          to  an  intercreditor  agreement  with  RZB  in  form  and  substance
          satisfactory  to  RZB.

     16.  Notices.  Any  notice  or request hereunder may be given to Obligor or
          -------
     to  RZB  at  their  respective  addresses  set forth below or at such other
     address as may hereafter be specified in a notice designated as a notice of
     change  of  address under this Section. Any notice or request hereunder may
     be  given  by,  in  the  case  of  notices  or  requests  to Obligor, mail,
     commercial  courier  service,  telex,  or  telegram,  or  by  telephone
     subsequently  confirmed by mail, commercial courier service, return receipt
     requested,  or by and in the case of notices to RZB, registered mail, telex
     or  telegram,  subsequently  confirmed by such registered mail. Notices and
     requests to Obligor shall, in the case of those by mail, commercial courier
     service,  telex or telegram, be deemed to have been given when deposited in
     the  mail,  first-class  postage  prepaid,  or  delivered  to  such courier
     service,  the  telegraph office or telex operator, addressed as provided in
     this  Section,  and in the case of those by telephone, when so communicated
     to  Obligor;  notices  to  RZB shall be deemed to have been given only when
     actually  received  by  RZB  at  its address determined as provided in this
     Section.  Any  requirement under applicable law of reasonable notice by RZB
     to  Obligor  of any event shall be met if notice is given to Obligor in the
     manner  prescribed  above  at  least seven days before (a) the date of such
     event  or  (b)  the  date  after  which  such  event  will  occur.

                                      -9-
<PAGE>
17.  General.
     -------

     a.        If this Agreement is executed by two or more Obligors, they shall
          be  jointly  and  severally  liable  hereunder,  all provisions hereof
          regarding  the  Obligations  or  the  Collateral  shall  apply  to the
          Obligations  and  Collateral of any or all of them and the termination
          of  this  Agreement  as  to  one  or  more  of such Obligors shall not
          terminate  this  Agreement  as  to  any  remaining  Obligors.

     b.        This  Agreement  shall  be  binding  upon  the  heirs, executors,
          administrators,  assigns  or  successors  of  each  of the undersigned
          Obligors  and shall inure to the benefit of and be enforceable by RZB,
          its  successors,  transferees  and  assigns.

                                      -10-
<PAGE>
     c.        If  any  provision  hereof  is  invalid  and unenforceable in any
          jurisdiction,  then,  to  the fullest extent permitted by law, (i) the
          other  provisions hereof shall remain in full force and effect in such
          jurisdiction and shall be liberally construed in favor of RZB in order
          to  carry out the intentions of the parties hereto as nearly as may be
          possible, and (ii) the invalidity or unenforceability of any provision
          hereof  in  any  jurisdiction  shall  not  affect  the  validity  or
          enforceability  of  such  provision  in  any  other  jurisdiction.

Dated:  September 15, 2004
                  --

RIO VISTA ENERGY PARTNERS L.P.

By:  RIO VISTA GP LLC, general partner

     By: /s/ Richard Shore, Jr.
         -----------------------------
     Name: Richard  Shore,  Jr.
           ---------------------------
     Title: President
            --------------------------

Address:

Rio Vista Energy Partners L.P.                   Telephone:   713-467-8253
820 Gessner Road                                 Telefax:     713-467-8258
Houston,  TX     77024

Accepted: September ___, 2004

RZB FINANCE LLC

By:  /s/ Pearl Geffers
     ---------------------------------
     Pearl Geffers

Title: First Vice President
        ------------------------------

By:  /s/  Griselda Alvizo
     ---------------------------------
     Griselda Alvizo

Title: Vice President
       -------------------------------

Address of RZB:

     RZB Finance LLC                             Telephone:   212-845-4113
     1133 Avenue of the Americas                 Telefax:     212-944-6387
     New York, New York 10036

                                      -11-
<PAGE>
                                   SCHEDULE A
                                   ----------

1.   Trade  Names  or  Trade  Styles  used  by  Obligor.
     --------------------------------------------------

None.

2.   Obligor's  Chief  Executive  Office.
     -----------------------------------

820 Gessner Road
Suite 1285
Houston, TX 77024

3.   All  Locations  of  Collateral.
     ------------------------------

Terminal/Pipeline facilities: Brownsville, Texas
Personal Property, intangibles, fixtures: Houston, Texas

Terminal/Pipeline facilities: Matamoros, Mexico
Storage facilities: Saltillo, Mexico
Office: Mexico City, Mexico

4.   All  Locations  of  Obligor's  Books  and  Records.
     --------------------------------------------------

Brownsville, Texas
El Segundo, California

                                      -12-
<PAGE>

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