AMENDMENT
                            TO AGREEMENT AND PLAN OF
                                 REORGANIZATION
                                       OF
                               ENSTAR CORPORATION



              This Amendment to Agreement and Plan of
Reorganization of ENSTAR
Corporation (the "Amendment") is made and entered into as of May
1, 1990, among
Unimar Company, a Texas general partnership ("Unimar"),
Ultrastar, Inc., a
Delaware corporation ("Ultrastar"), Unistar, Inc., a Delaware
corporation
("Unistar"), ENSTAR Corporation, a Delaware corporation
("ENSTAR"), Ultramar
Production Company, a Delaware corporation ("UPC"), Union Texas
Development
Corporation, a Delaware corporation ("UT Development"), Union
Texas Petroleum
Corporation, a Delaware corporation ("UTPC") and Ultramar America
Limited, a
Delaware corporation ("Ultramar") and amends the Agreement and
Plan of
Reorganization of ENSTAR Corporation, dated December 22, 1989
(the
"Agreement"), among Unimar, Ultrastar, Unistar, ENSTAR, Ultramar
Production, UT
Development, UTPC and Ultramar (collectively, the "Parties").

                             W I T N E S S E T H :
              WHEREAS, the Parties entered into the Agreement to
provide for
the Reorganization;

              WHEREAS, Section 5.1(e) of the Agreement provides
that the
receipt of a favorable IRS Ruling by Unimar and ENSTAR is a
condition to the
obligation of the Parties to consummate the Reorganization;

              WHEREAS, based on advice from the IRS, ENSTAR has
withdrawn  its
request for a favorable IRS Ruling regarding the application of
Section 355 of
the Code to the Reorganization;

              WHEREAS, the Parties desire to waive the receipt of
a favorable
IRS Ruling as a condition to the consummation of the
Reorganization; and

              WHEREAS, the Parties desire to amend the Agreement
to reflect
their agreement as to the foregoing and certain other matters;

              NOW, THEREFORE, in consideration of and subject to
the mutual
agreements, terms and conditions herein contained, the Parties
hereby agree as
follows:

              1.     Amendment to Section 1.1.  Section 1.1 of
the Agreement is
       hereby amended by the addition of the following
subparagraphs (c) and
       (d) after subparagraph (b):

              "(c) ENSTAR shall transfer to UT Development all
right, title
              and interest of Enstar in and to any and all
accounts
              receivable attributable to the UT Assets;           
    





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               "(d) ENSTAR shall transfer to UPC all right, title
and interest 
               of ENSTAR in and to any and all accounts
receivable
               attributable to the UPC Assets."                   
    
                                                          
               2.     Amendment to Section 2.2.  Section 2.2 of
the Agreement 
        is hereby amended by the addition of the following
subparagraph (xii)
        after subparagraph (xi):                                 

                                                                  
       
              (xii) the Fee Agreement, in substantially the form
attached
              hereto as Exhibit P, providing for the payment of
certain fees
              and expenses of UTPC and Ultramar."               
                                                               
               3.     Section 4.1 of the Agreement is hereby
amended in its
        entirety to read as follows:         
                                                                  
          
               "Section 4.1.  IRS Covenant.  From the date
hereof, each
               of the parties to this Agreement covenants and
agrees that it
               will fully comply with the requirements,
representations and
               conditions that were set forth in the IRS Request
and the
               statutory basis for such Request for so long as
necessary in
               order for the Reorganization to qualify as a
distribution to
               which Section 355 of the Code applies."            
       
                                                           
               4.     Execution of Amended and Restated
Partnership Agreement.
        If, on or before the Closing Date, Ultrastar and Unistar
shall have
        executed an Amended and Restated Agreement of General
Partnership of
        Unimar Company, the Parties shall be deemed to
                                        
        
        
        
        
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       have waived the requirement under Section 5.1(b) of the
Agreement that
       Ultrastar and Unistar (i) shall have performed all
obligations and
       agreements and complied with all covenants and conditions
applicable to
       Ultrastar and Unistar contained in the Partnership
Amendment and (ii)
       shall have executed and delivered the Partnership
Amendment prior to or
       on the Closing Date.

              5.     Waiver of Execution of Discharge Agreement. 
If, on or
       before the Closing Date, the Discharge Agreement shall not
have been
       executed by all the parties thereto, the parties shall be
deemed to have
       waived the requirement under Section 5.1(b) of the
Agreement that each
       of the Parties (i) shall have performed all obligations
and agreements
       and complied with all covenants and conditions applicable
to it
       contained in the Discharge Agreement and (ii) shall have
executed and
       delivered the Discharge Agreement prior to or on the
Closing Date.

              6.     Waiver of IRS Ruling.  The Parties hereby
waive the
       requirement under Section 5.1(e) of the Agreement that the
receipt of a
       favorable IRS Ruling by Unistar and Ultrastar is a
condition to the
       closing of the Reorganization.

              7.     Amendment to Section 9.7.  Section 9.7 of
the Agreement is
       hereby amended by (i) substituting the term "Fee
Agreement" for
       "Partnership Agreement" in the first





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        sentence of paragraph (a) and for "Unimar Partnership
Agreement" in the
        first sentence of paragraph (g) and (ii) the addition of
the following
        paragraph (h) after paragraph (g):

        "(h)     Any receivable which relates to the period prior
to the
        Valuation Date and is described in the Closing Period
Adjustment
        Statement (other than receivables in respect of
indebtedness owing
        by the Partnerships to ENSTAR) which (i) has been
assigned to
        UT Development or UPC pursuant to the terms of this
Agreement and
        the Conveyances and (ii) has not been paid in accordance
with
        its terms, shall be payable by ENSTAR to UT Development
or UPC, 
        as the case may be.  The amount of any such receivable
shall
        be paid within 30 days following receipt by ENSTAR of
notice of
        non-payment, which notice must be received by ENSTAR
within
        one year from the Closing Date.  The non-submitting party
shall
        have the right to audit receivable claims submitted to
ENSTAR
        for a period of 90 days following receipt by ENSTAR of
such
        notice of non-payment."

              8.     Amendment to Section 9.8.  Section 9.8 of
the Agreement
        is hereby amended by (i) deleting paragraphs (a) and (b)
and
        substituting the following:





                                      -5-

        "(a)     After the Closing, ENSTAR, UPC and UT
Development shall,   
        immediately upon their receipt, turn over or cause to be
turned
        over to UPC, UT Development or their affiliates, as the
case may be,
        any amounts from or related to the Transferred Assets
received by
        ENSTAR, UPC, UT Development or their affiliates, which
amounts are
        accounted for in the Closing Period Adjustment Statements
and have
        not been previously turned over in accordance with the
Closing
        Period Adjustment Statements.

        (b)      After the Closing, ENSTAR, UPC and UT
Development shall,
        immediately upon their receipt, turn over or cause to be
turned over
        to UPC, UT Development or their affiliates, as the case
may be, any
        invoices or any other demand for payment for costs and
expenses that
        were incurred as costs for operation or ownership of or
expenses
        related to the Transferred Assets during the Closing
Period and which
        are accounted for in the Closing Period Adjustment
Statements and
        have not previously been turned over in accordance with
the Closing
        Period Adjustment Statements."





                                      -6-

       and (ii) the addition of the following paragraph after
paragraph (c):

        "(d)    After the Closing, UPC and UT Development shall,
immediately
        upon their receipt, turn over or cause to be turned over
to ENSTAR all
        amounts that were not, and should not properly be,
included in the
        Closing Period Adjustment Statements, which amounts
relate to a
        period prior to the Valuation Date."      

              9.     Closing Date.  The Parties hereby agree that
the
       preliminary closing of the Reorganization shall be held on
April 30,
       1990 at 1:00 p.m., Houston, Texas time at the offices of
Andrews & Kurth
       and the closing of the Reorganization shall be held on May
1, 1990 (the
       "Closing Date") at 9:00 a.m., Houston, Texas, time at the
offices of
       Andrews & Kurth.

              10.    Deletion of References to Newstar.  All
references to
       Newstar, Inc. and Newstar contained in the Agreement are
hereby deleted
       and replaced with the words "Ultramar Production Company"
and "UPC"
       respectively.

              11.    Utilization of Information.  In the event
the Partnership
       Amendment is not executed on or before the Closing Date,
each of the
       Parties hereby agrees that (i) Ultrastar and its
affiliates shall have
       the right to utilize information regarding the operations
of the





                                      -7-

       UPC Assets and to deal with the UPC Assets and any
properties in the
       vicinity thereof for its own account and (ii) Unistar and
its affiliates
       shall have the right to utilize information regarding the
operations of
       the UT Assets and to deal with the UT Assets and any
properties in the
       vicinity thereof for its own account.  Neither Ultrastar
nor Unistar
       shall be obligated to disclose to or share with Unimar (or
the other
       partner in Unimar) any compensation or profit attributable
to the UPC
       Assets or the UT Assets, as the case may be, or any
properties in the
       vicinity thereof.

              12.    Continuance of Agreement.  The Agreement
shall remain in
       full force and effect and, except as specifically provided
herein, none
       of its terms or provisions are modified or amended in any
manner
       whatsoever.

              13.    Conflicts.  In the event there shall be any
conflict
       between the provisions of this Amendment and the
Agreement, the
       provisions of this Amendment shall control.

              14.    GOVERNING LAWS.  THE TERMS OF THIS AMENDMENT
SHALL BE
       GOVERNED BY, AND CONSTRUED IN ACCORDANCE WITH, THE LAWS OF
THE STATE OF
       TEXAS (EXCLUDING ANY CONFLICTS-OF-LAW RULE OR PRINCIPLE
THAT MIGHT REFER
       SAME TO THE LAWS OF ANOTHER JURISDICTION), EXCEPT TO THE
EXTENT THAT
       SAME ARE MANDATORILY





                                      -8-

SUBJECT TO THE LAWS OF ANOTHER JURISDICTION PURSUANT TO
THE LAWS OF SUCH OTHER JURISDICTION.

              15.    Definitions.  Terms not otherwise defined
herein shall
       have the respective meanings assigned to such terms in the
Agreement.

              16.    Counterparts.  This Amendment may be
executed in any
       number of counterparts, each of which when so executed
shall be
       deemed an original and all of which together shall
constitute one and
       the same instrument.

              17.    Severability.  If any provision of this
Amendment is
       invalid, illegal, or unenforceable, the remainder of the
Amendment
       shall remain in full force and effect.

              IN WITNESS WHEREOF, each of the Parties hereto has
caused this
Amendment to be signed by its duly authorized officer as of the
date first
above written.

                                   UNIMAR COMPANY

                                   By:  Unistar, Inc., a General
Partner 

                                       By:   /s/W.M. KRIPS 
                                      
- -----------------------------
                                       Name: W.M. KRIPS           
      
                                       Title: President





                                      -9-

                                       By:  Ultrastar, Inc., a
General Partner

                                            By:  /s/ROBERT W.
BLAND       
                                                
- ----------------------------
                                            Name:  ROBERT W.
BLAND       
                                            Title: Senior Vice
President        


                                        UNISTAR, INC.

                                            By:  /s/W.M. KRIPS    
             
                                                
- ----------------------------
                                                 Name:  W.M.
KRIPS           
                                                 Title: President 
    


                                         ULTRASTAR, INC.

                                             By:  /s/ROBERT W.
BLAND       
                                                 
- --------------------------- 
                                             Name:  ROBERT W.
BLAND       
                                             Title: Senior Vice
President   


                                         ENSTAR CORPORATION

                                             By:  /s/ROBERT W.
BLAND       
                                                 
- --------------------------- 
                                             Name:  ROBERT W.
BLAND   
                                             Title: President     
   


                                         ULTRAMAR PRODUCTION
COMPANY

                                             By:  /s/ROBERT W.
BLAND       
                                                 
- ---------------------------   
                                             Name:  ROBERT W.
BLAND       
                                             Title: President     
       





                                      -10-

                                             UNION TEXAS
DEVELOPMENT
                                               CORPORATION

                                                 By:  /s/W.M.
KRIPS         
                                                     
- ------------------------- 
                                                      Name:  W.M.
KRIPS  
                                                      Title:
President


                                             UNION TEXAS
PETROLEUM
                                               CORPORATION

                                                 By:  /s/W.M.
KRIPS
                                                     
- -------------------------
                                                 Name:  W.M.
KRIPS 
                                                 Title: Vice
President
                                                                  
            

                                             ULTRAMAR AMERICA
LIMITED

                                                 By:  /s/ROBERT
W. BLAND       
                                                     
- -------------------------
                                                 Name:  ROBERT W.
BLAND        
                                                 Title: Vice
President 





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