UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549


                                    FORM 8-K

                                 CURRENT REPORT

                       Pursuant to Section 13 or 15(d) of
                       the Securities Exchange Act of 1934


      Date of Report (Date of earliest event reported):  September 16, 2004


                             PENN OCTANE CORPORATION
             (Exact name of registrant as specified in its charter)


          Delaware                 000-24394              52-1790357
          (State of                (Commission            (IRS Employer
          Incorporation)           File Number)           Identification No.)


          77-530 Enfield Land, Bldg D
          Palm Desert, California                         92211
          (Address of principal executive offices)        (Zip Code)

                                 (760) 772-9080
              (Registrant's telephone number, including area code)

                                       N/A
          (Former Name or Former Address, if Changed Since Last Report)


     Check the appropriate box below if the Form 8-K filing is intended to
simultaneously satisfy the filing obligation of the registrant under any of the
following provisions (see General Instruction A.2. below):

     [_] Written communications pursuant to Rule 425 under the Securities Act
(17 CFR 230.425)

     [_] Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17
CFR 240.14a-12)

     [_] Pre-commencement communications pursuant to Rule 14d-2(b) under the
Exchange Act (17 CFR 240.14d-2(b))

     [_] Pre-commencement communications pursuant to Rule 13e-4(c) under the
Exchange Act (17 CFR 240.13e-4(c))


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Item 1.01.  Entry into a Material Definitive Agreement

     On September 16, 2004, Penn Octane Corporation (the "Company") entered into
a  series  of  agreements  in  connection  with its proposed distribution to its
common  stockholders of the common units of Rio Vista Energy Partners L.P. ("Rio
Vista"),  currently  a  wholly-owned  subsidiary  of  the  Company,  as follows:

DISTRIBUTION  AGREEMENT

     Penn  Octane  entered  into  a  distribution  agreement  ("Distribution
Agreement")  with  Rio  Vista  and  its  subsidiaries  in  connection  with  the
distribution.  This  agreement,  as  discussed  in  greater  detail  below:

     -    provides for the principal corporate transactions to be effected in
          connection with the distribution; and

     -    provides for other matters relating to Penn Octane's relationship with
          Rio Vista and its subsidiaries, and the rights and obligations of Penn
          Octane and the rights and obligations of Rio Vista, following the
          distribution.

The principal terms of the Distribution Agreement include:

Corporate Restructuring Transactions and Assignments

On  or  before  the  distribution date, Penn Octane and Rio Vista will, and will
cause  their  respective  subsidiaries to, take such actions as are necessary to
cause, effect and consummate the corporate restructuring transactions identified
in  the  Distribution  Agreement  and  any  other  agreement  relating  to  the
distribution.

In  addition,  on  or  before  the  distribution  date  or as soon as reasonably
practicable  after  that  date,  subject  to  obtaining any required third party
consent:

     -    Penn Octane will transfer or cause to be transferred to Rio Vista or a
          subsidiary of Rio Vista all transferable licenses and permits that
          relate to Rio Vista's business and are held in the name of Penn Octane
          or any of its subsidiaries or their respective employees, officers,
          directors, stockholders or agents;

     -    Penn Octane will assign, transfer and convey or cause to be assigned,
          transferred and conveyed to Rio Vista or a subsidiary of Rio Vista all
          of its right, title and interest in and to any and all agreements that
          relate exclusively to Rio Vista's business, Rio Vista or any of Rio
          Vista's subsidiaries; and

     -    any agreement that inures to the benefit of Penn Octane or a
          subsidiary of Penn Octane and to the benefit of Rio Vista or a
          subsidiary of Rio Vista, will be assigned so that each party will be
          entitled to the rights and benefits inuring to its business under that
          agreement.


                                  Page 2 of 9

Conditions to the Distribution

The  Distribution  Agreement  provides  that  the  following  conditions must be
satisfied  or  waived  before or as of the date of the distribution in order for
the  distribution  to  occur:

     -    the Form 10 filed by Rio Vista with the Securities and Exchange
          Commission ("SEC") under the Securities Exchange Act of 1934 must have
          become effective and not be subject to a stop order or a proceeding
          for that purpose;

     -    the common units of Rio Vista to be delivered in the distribution must
          have been approved for trading on the National Market System of the
          Nasdaq Stock Market or other public market acceptable to the Board of
          Directors of Penn Octane, subject to official notice of issuance;

     -    the Board of Directors of Penn Octane and the independent committee of
          the Board of Directors of Penn Octane must be satisfied that the
          distribution will be made out of its surplus within the meaning of
          Section 170 of the General Corporation Law of the State of Delaware
          and Penn Octane will not be insolvent or have unreasonably small
          capital with which to engage in its businesses following the
          distribution;

     -    the Board of Directors of Penn Octane and the independent committee of
          the Board of Directors of Penn Octane must have approved the
          distribution and not have abandoned, deferred or modified the
          distribution or terms thereof;

     -    Penn Octane and the operating subsidiary of Rio Vista shall have duly
          executed and delivered the purchase contract for the sale of liquefied
          petroleum gas by Penn Octane to the operating subsidiary of Rio Vista;

     -    the Distribution Agreement, the Omnibus Agreement (described below),
          the Contribution, Conveyance and Assumption Agreement (described
          below) and each of the other agreements reasonably necessary or
          appropriate to consummate the corporate restructuring transactions and
          the distribution must have been duly executed and delivered by the
          parties;

     -    no order, injunction or decree issued by any court or agency of
          competent jurisdiction or other legal restraint or prohibition
          preventing the distribution or any of the other transactions
          contemplated by the Distribution Agreement and the other agreements
          relating to the distribution may be in effect;

     -    the Board of Directors of Penn Octane and the independent committee of
          the Board of Directors of Penn Octane shall have received a copy of
          the independent appraisal of the assets to be transferred by Penn
          Octane to Rio Vista conducted by Baker & O'Brien, Inc. as of January
          1, 2004, and each of the Board of Directors of Penn Octane and the
          independent committee of the Board of Directors of Penn Octane shall
          have determined in their sole discretion that, based on such
          independent appraisal, the estimated tax liabilities to be incurred by
          Penn Octane as a result of the distribution are acceptable; and

     -    any material governmental and third party approvals and consents
          necessary to consummate the distribution and related transactions must
          have been obtained and must be in full force and effect.


                                  Page 3 of 9

Transaction Expenses

Penn  Octane  will  be  responsible for all transaction expenses relating to the
distribution  incurred  by  Penn  Octane,  its  subsidiaries,  Rio Vista and Rio
Vista's  subsidiaries.

Termination

The Board of Directors of Penn Octane and the independent committee of the Board
of  Directors  of  Penn  Octane  may  abandon the distribution and terminate the
distribution  agreement  at  any  time  before  the  distribution.

OMNIBUS AGREEMENT

     Penn  Octane  entered  into an omnibus agreement ("Omnibus Agreement") with
Rio Vista and its subsidiaries that governs, among other things, indemnification
obligations  among the parties to the agreement, related party transactions, the
provision  of  general  administration  and support services by Penn Octane.  In
this  agreement,  as  discussed  in  greater  detail  below:

     -    Penn Octane agrees to indemnify Rio Vista for environmental losses
          arising prior to the distribution, preexisting litigation and tax
          liabilities.

     -    Rio Vista agrees to indemnify Penn Octane for environmental losses
          arising after the distribution and for federal income tax liabilities
          resulting from the distribution in excess of $2.5 million.

     -    Rio Vista agrees to reimburse Penn Octane for the provision of general
          and administrative services and other expenses incurred on Rio Vista's
          behalf.

     -    Rio Vista is prohibited from entering into certain material agreements
          between Rio Vista and Penn Octane without the approval of the
          conflicts committee of Rio Vista's general partner's board of
          managers.

Indemnification  Provisions

Under  the  Omnibus  Agreement,  Penn  Octane will indemnify Rio Vista after the
completion  of  the  distribution  against:

     -    certain potential environmental liabilities associated with the
          operation of the assets contributed to Rio Vista, and assets retained,
          by Penn Octane that relate to events or conditions occurring or
          existing before the completion of the distribution.

Penn Octane will also indemnify Rio Vista for liabilities relating to:

     -    legal actions against Penn Octane;

     -    events and conditions associated with any assets retained by Penn
          Octane;


                                  Page 4 of 9

     -    certain defects in the title to the assets contributed to Rio Vista by
          Penn Octane that arise within three years after the completion of the
          distribution to the extent such defects materially and adversely
          affect Rio Vista's ownership and operation of such assets;

     -    Rio Vista's failure to obtain certain consents and permits necessary
          to conduct Rio Vista's business to the extent such liabilities arise
          within three years after the completion of the distribution; and

     -    certain income tax liabilities attributable to the operation of the
          assets contributed to Rio Vista prior to the time that they were
          contributed.

Rio  Vista  will  indemnify  Penn  Octane  for  certain  potential environmental
liabilities associated with the operation of the assets contributed to Rio Vista
that  relate  to events or conditions occurring or existing after the completion
of  the  distribution  and  for federal income tax liabilities in excess of $2.5
million  incurred  by  Penn  Octane  as  a  result  of  the  distribution.

Services

Under  the  Omnibus Agreement, Penn Octane will provide Rio Vista with corporate
staff  and  support  services  that  are  substantially  identical in nature and
quality  to  the  services previously provided by Penn Octane in connection with
its  management  and  operation  of  the assets of Rio Vista during the one-year
period prior to the completion of the distribution.  These services will include
centralized  corporate  functions,  such  as  accounting, treasury, engineering,
information  technology,  insurance,  administration  of  employee  benefit  and
incentive  compensation plans and other corporate services.  Penn Octane will be
reimbursed  for  the  costs  and expenses it incurs in rendering these services,
including  an overhead allocation to Rio Vista of Penn Octane's indirect general
and  administrative  expenses  from  its corporate allocation pool.  The general
partner of Rio Vista will determine the general and administrative expenses that
will  be  allocated  to Rio Vista.  Administrative and general expenses directly
associated  with  providing  services to Rio Vista (such as legal and accounting
services)  are  not  included  in  the  overhead  allocation  pool.

Related Party Transactions

The  Omnibus  Agreement  prohibits  Rio  Vista  from  entering into any material
agreement with Penn Octane without the prior approval of the conflicts committee
of  the  board of managers of the general partner of Rio Vista.  For purposes of
the  Omnibus Agreement, the term material agreements means any agreement between
Rio  Vista  and Penn Octane that requires aggregate annual payments in excess of
$100,000.

Amendment and Termination

The  Omnibus  Agreement  may  be  amended  by  written agreement of the parties;
provided,  however  that  it  may  not  be  amended  without the approval of the
conflicts  committee of the general partner of Rio Vista if such amendment would
adversely  affect  the  unitholders  of Rio Vista.  The Omnibus Agreement has an
initial  term  of  five years that automatically renews for successive five-year
terms  and,  other  than  the  indemnification provisions, will terminate if Rio
Vista  is  no  longer  an  affiliate  of  Penn  Octane.


                                  Page 5 of 9

CONTRIBUTION, CONVEYANCE AND ASSUMPTION AGREEMENT

     Penn  Octane  entered  into  a  contribution,  conveyance  and  assumption
agreement  ("Contribution, Conveyance and Assumption Agreement") with Rio Vista,
the  operating  subsidiary of Rio Vista and the general partner of the operating
subsidiary of Rio Vista and provides for the contribution and conveyance by Penn
Octane  of  the  assets  comprising  Rio Vista's business, including the capital
stock  of  Penn  Octane's  Mexican  subsidiaries  and the contracts, permits and
leases  material  to  Rio  Vista's  business, to the operating subsidiary of Rio
Vista,  the  contribution of Penn Octane's 99.9% limited partner interest in the
operating  subsidiary  of Rio Vista to Rio Vista and the assumption by Rio Vista
and  the  operating  subsidiary  of Rio Vista of all obligations and liabilities
associated  with  such assets, that arise from and after the consummation of the
transaction  under  this  agreement,  to the full extent that Penn Octane or the
Mexican  subsidiaries  would  have  been obligated to pay, perform and discharge
such  obligations  and  liabilities  in the future but for the execution of this
agreement.

CONVEYANCE AGREEMENT

     Pursuant  to  the  Contribution,  Conveyance and Assumption Agreement, Penn
Octane  executed  a  conveyance  agreement  ("Conveyance  Agreement")  with  the
operating  subsidiary  of  Rio  Vista  that conveys the following assets of Penn
Octane  to  the  operating  subsidiary of Rio Vista effective as of 4:58 p.m. on
September  30,  2004:

Brownsville Terminal Facilities:
     Building
     LPG Terminal facilities
     Tank Farm
     Leasehold improvements
     Capital construction in progress
     Equipment

US Pipelines and Rights Of Way:
     6" and 8" (Brownsville terminal to US Border)
     Various rights of way obtained in connection with operation of US Pipelines
       between Brownsville Terminal and US Border

Other:
     Land acquired in Brownsville in vicinity of the US Pipelines between
       Brownsville Terminal and US border
     Inventory located in storage tanks and pipelines located in Brownsville
       (and extending to storage and pipelines located in assets held by the
       Mexican subsidiaries)

Investment in Subsidiaries:
     Penn Octane de Mexico, S. de R.L. de C.V.
     Termatsal, S. de R.L. de C.V.
     Penn Octane International LLC


                                  Page 6 of 9

Contracts and Leases (assumed and/or assigned):
     Lease Agreements
          Port of Brownsville
               LPG Terminal Facility
               Tank Farm Lease
     US State Department Permit
     Other licenses and permits in connection with ownership and operation of
       the US pipelines between Brownsville and US border

PURCHASE AGREEMENT FOR LPG

     Penn  Octane  entered into a purchase agreement ("Purchase Agreement") with
the operating subsidiary of Rio Vista pursuant to which the operating subsidiary
of  Rio  Vista  agrees  to  purchase all of its LPG requirements for sales which
utilize  the assets transferred to the operating subsidiary of Rio Vista by Penn
Octane  to the extent Penn Octane is able to supply such LPG requirements.  This
agreement  further provides that the operating subsidiary of Rio Vista will have
no obligation to purchase LPG from Penn Octane to the extent the distribution of
such LPG to Rio Vista's customers would not require the use of any of the assets
Penn  Octane  contributes  to  the  operating  subsidiary of Rio Vista under the
Contribution,  Conveyance  and  Assumption  Agreement.  The  Purchase  Agreement
terminates  on  the  earlier  to  occur  of:

     -    Penn Octane ceases to have the right to access the Seadrift pipeline
          that connects to Rio Vista's Brownsville terminal facilities; and

     -    the operating subsidiary of Rio Vista ceases to sell LPG using any of
          the assets contributed by Penn Octane to the operating subsidiary of
          Rio Vista pursuant to the contribution, conveyance and assumption
          agreement.

The price Rio Vista will pay for LPG under this contract is indexed to the price
quoted  by the Oil Price Information Service for Mt. Belvieu non-tet propane and
non-tet  normal  butane,  plus  other  costs and amounts based on a formula that
takes  into  consideration operating costs to both Penn Octane and to Rio Vista.

LIMITED PARTNERSHIP AGREEMENTS AND LIMITED LIABILITY COMPANY AGREEMENT

     In addition to the agreements described above, Penn Octane executed the
following agreements in the capacity indicated:

     -    First Amended and Restated Agreement of Limited Partnership of Rio
          Vista Energy Partners L.P., in Penn Octane's capacity as
          organizational limited partner;

     -    First Amended and Restated Agreement of Limited Partnership of Rio
          Vista Operating Partnership L.P., the operating subsidiary of Rio
          Vista, in Penn Octane's capacity as limited partner; and

     -    Amended and Restated Limited Liability Company Agreement of Rio Vista
          GP LLC, the general partner of Rio Vista, in Penn Octane's capacity as
          member.


                                  Page 7 of 9

Each of the foregoing agreements is described in the registration statement on
Form 10 filed by Rio Vista with the SEC on August 26, 2004, as amended by
Amendment No. 1 thereto filed with the SEC on September 16, 2004 (SEC File No.
000-50394).


                                  Page 8 of 9

     SIGNATURES

     Pursuant to the requirements of the Securities Exchange Act of 1934, the
registrant has duly caused this report to be signed on its behalf by the
undersigned hereunto duly authorized.

                                         PENN OCTANE CORPORATION


                                         By:   /s/ Ian T. Bothwell
                                            ---------------------------------
                                            Name:  Ian T. Bothwell
                                            Title:  Vice President, Treasurer,
                                               Assistant Secretary, Chief
                                               Financial Officer and Principal
                                               Accounting Officer
Date:  September 22, 2004


                                  Page 9 of 9