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                                                                    Exhibit 10.5
                           FOURTH AMENDMENT AGREEMENT

         This Fourth Amendment Agreement, effective as of June 16, 1995
("Amendment"), is by and among (i) Union Texas Petroleum Holdings, Inc., a
Delaware corporation ("Company"), (ii) the undersigned lenders ("Banks") which
are parties to the Amended and Restated Credit Agreement dated as of May 13,
1994, as amended by the First Amendment Agreement dated as of November 21,
1994, the Second Amendment Agreement dated as of January 31, 1995 and the Third
Amendment Agreement dated as of April 24, 1995 (as so amended, the "Agreement")
among the Company, the lenders party thereto, NationsBank of Texas, N.A., as
agent ("Agent"), and the Co-Agents named therein, (iii) the Agent and (iv) the
Co-Agents.  In consideration of the mutual covenants contained herein, the
Company, the Banks, the Co-Agents and the Agent agree as set forth herein.

         1.      Amendments to Credit Agreement.  The Agreement is hereby
amended as follows:

                 1.1.  Section 1.01.  The following respective definitions set
forth in Section 1.01 of the Agreement are hereby amended to read as follows:

                 "Adjusted Equity" means the consolidated stockholders equity
         of the Company and its Consolidated Subsidiaries, as determined on a
         consolidated basis in accordance with generally accepted accounting
         principles, adjusted to exclude (i) any cumulative foreign exchange
         translation adjustments, (ii) any non-cash write-up or writedown of
         any assets of the Company and its Consolidated Subsidiaries made after
         March 31, 1995 in accordance with generally accepted accounting
         principles, and (iii) the non-cash effect of the adoption of any
         change after March 31, 1995 required by generally accepted accounting
         principles.

                 "Margin Increase Condition" exists at all times during which
         any senior unsecured long-term debt of the Company is rated below BBB-
         by S&P.

         Section 1.01 of the Agreement is hereby further amended by deleting
therefrom the definitions of "Additional Margin Increase Condition" and "Margin
Period".

                 1.2.     Section 2.07(a).  The first sentence of Section
2.07(a) of the Agreement is hereby amended to read as follows:

                 (a)      If such Loan is a Base Rate Loan, for each day that
such Loan is a Base Rate Loan, at a rate per annum equal to the sum of (i) the
Base Rate for such day plus (ii) at such times as the Margin Increase Condition
exists, 1/4% plus (iii) at such times as any Event of Default exists, 1%.
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                 1.3.     Section 2.07(b).  The first sentence of Section
2.07(b) is hereby amended to read as follows:

                 (b)      If such Loan is a Euro-Dollar Loan, at a rate per
annum equal at all times during any Interest Period for such Loan to the sum of
(i) 0.575% plus (ii) the applicable London Interbank Offered Rate plus (iii) at
such times as the Margin Increase Condition exists, 1/4% plus (iv) at such
times as any Event of Default exists, 1%; provided that if any Euro-Dollar Loan
or any portion thereof shall, as a result of clause (1)(c)(i) of the definition
herein of "Interest Period", have an Interest Period of less than one month,
such portion shall bear interest during such Interest Period at the rate
applicable to Base Rate Loans during such period.

                 1.4.     Section 2.07(c).  The first sentence of Section
2.07(c) is hereby amended to read as follows:

                 (c)      If such Loan is a Sterling Loan, at a rate per annum
equal at all times during any Interest Period for such Loan to the sum of (i)
0.575% plus (ii) the applicable Sterling Interbank Offered Rate plus (iii) at
such times as the Margin Increase Condition exists, 1/4% plus (iv) at such
times as any Event of Default exists, 1%; provided that if any Sterling Loan or
any portion thereof shall, as a result of clause (4)(c)(i) of the definition
herein of "Interest Period", have an Interest Period of less than one month,
such portion shall bear interest during such Interest Period at the rate
otherwise applicable to such Sterling Loans during such period plus 1/2%.

                 1.5.     Section 2.07(d).  Section 2.07(d) is hereby amended
to read as follows:

                 (d)      Any overdue principal of or interest on any
Euro-Dollar Loan shall bear interest, payable on demand, for each day from and
including the date payment thereof was due to but excluding the date of actual
payment, at a rate per annum equal to the sum of 1% plus the higher of (i) the
sum of 0.575% plus the London Interbank Offered Rate applicable to such Loan
plus at such times as the Margin Increase Condition exists, 1/4% and (ii) the
sum of (1) 0.575% plus (2) the average (rounded upward, if necessary, to the
next higher 1/16 of 1%) of the respective rates per annum at which one day (or,
if such amount due remains unpaid more than three Euro-Dollar Business Days,
then for such other period of time not longer than three months as the Agent
may select) deposits in Dollars in an amount approximately equal to such
overdue payment due to each of the Reference Banks are offered to such
Reference Bank in the London interbank market for the applicable period
determined as provided above plus (3) at such times as the Margin Increase
Condition exists, 1/4% (or, if the circumstances described in clause (i) or
(ii) of Section 8.01(a) shall exist, at a rate per annum equal to the sum of 1%
plus the rate applicable to Base Rate Loans for such day).



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                 1.6.     Section 2.07(e).  Section 2.07(e) is hereby amended
to read as follows:

                 (e)      Any overdue principal of or interest on any Sterling
Loan shall bear interest, payable on demand, for each day from and including
the date payment thereof was due to but excluding the date of actual payment,
at a rate per annum equal to the sum of 1% plus the higher of (i) the sum of
0.575% plus the Sterling Interbank Offered Rate applicable to such Loan plus at
such times as the Margin Increase Condition exists, 1/4% and (ii) the sum of
(1) 0.575% plus (2) the average (rounded upward, if necessary, to the next
higher 1/16 of 1%) of the respective rates per annum at which one day (or, if
such amount due remains unpaid more than three Sterling Business Days, then for
such other period of time not longer than three months as the Agent may select)
deposits in Sterling in an amount approximately equal to such overdue payment
due to each of the Reference Banks are offered to such Reference Bank in the
London interbank market for the applicable period determined as provided above
plus (3) at such times as the Margin Increase Condition exists, 1/4% (or, if
the circumstances described in clause (i) or (ii) of Section 8.01(b) shall
exist, at a rate per annum equal to the sum of 1% plus the rate applicable to
Base Rate Loans for such day).

                 1.7.     Section 5.01(d).  Section 5.01(d) of the Agreement is
hereby amended to read as follows:

                 (d)      as soon as available and in any event within 60 days
         after the end of each fiscal quarter of the Company, a certificate of
         the chief financial officer, the chief accounting officer or the
         treasurer of the Company certifying (i) whether the Margin Increase
         Condition exists as of the date of such certificate, (ii) the Unimar
         Percentage as of the end of such quarter and the amounts as of the end
         of such quarter of Consolidated Debt, Defeased Debt, Excluded
         Subordinated Debt, Debt of the Company and its Consolidated
         Subsidiaries determined on a consolidated basis, Debt of the Company
         and the Restricted Subsidiaries determined on a consolidated basis,
         Debt of Unimar, Debt of Unrestricted Subsidiaries, Excess Letter of
         Credit/Guarantee Amount, Non-Restricted Asset Non-Recourse Debt,
         Non-Recourse Debt of the Company and the Restricted Subsidiaries, and
         Restricted Subsidiaries Recourse Debt, and (iii) each Asset Sale that
         has been consummated during such quarter, the Fair Market Value of the
         Restricted Assets subject thereto, the amount of fees, commissions,
         expenses and taxes related thereto, the Net Sales Proceeds therefrom
         and the cumulative amount of the Excess Net Sales Proceeds from all
         Assets Sales since December 31, 1993;

                 1.8.     Section 5.05(a).  Section 5.05(a) of the Agreement is
hereby deleted from the Agreement.





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                 1.9.     Section 5.15.  Section 5.15 of the Agreement is
hereby amended by changing the amount "$300,000,000" set forth therein to
"$350,000,000".

                 1.10.    Section 8.01(a).  Clause (y) of Section 8.01(a) of
the Agreement is hereby amended to read as follows:

                          (y) if such Fixed Rate Borrowing is a Money Market
                 LIBOR Borrowing, the Money Market LIBOR Loans comprising such
                 Borrowing shall bear interest for each day from and including
                 the first day to but excluding the last day of the Interest
                 Period applicable thereto at the sum of the Base Rate for such
                 day plus at such times as the Margin Increase Condition
                 exists, 1/4% plus at such times as any Event of Default
                 exists, 1%.

                 1.11.    Section 9.05.  Section 9.05 of the Agreement is
hereby amended by deleting the second proviso thereof (which pertains to
amendments to or waivers of Section 5.05(a)).

         2.      Effectiveness.  The effectiveness of this Amendment is subject
to the receipt by the Agent of:

                 2.1.     counterparts of this Amendment signed by each of the
         parties hereto (or, in the case of any party as to which an executed
         counterpart shall not have been received, receipt by the Agent in form
         satisfactory to it of telegraphic, telex or other written confirmation
         from such party of execution of a counterpart hereof by such party);
         and

                 2.2.     a consent, duly executed by each of the Required
Guarantors, substantially in the form of Exhibit A hereto.

         3.      Miscellaneous.

                 3.1.  Amendments, Etc.  No amendment or waiver of any
provision of this Amendment, nor consent to any departure by the Company
therefrom, shall in any event be effective unless effected in accordance with
Section 9.05 of the Agreement.

                 3.2.  Governing Law.  This Amendment and the Agreement as
amended hereby shall be construed in accordance with and governed by the laws
of the State of Texas.

                 3.3.  Preservation.  Except as specifically modified by the
terms of this Amendment, all of the terms, provisions, covenants, warranties
and agreements contained in the Agreement (including, without limitation,
exhibits thereto) or any other





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Financing Document remain in full force and effect.  Undefined capitalized
terms used herein are used herein as defined in the Agreement as amended
hereby.

                 3.4.  Execution in Counterparts.  This Amendment may be
executed in any number of counterparts, each of which when so executed shall be
deemed to be an original, with the same effect as if the signatures thereto and
hereto were upon the same instrument.

                 3.5.  Representations and Warranties.  The Company hereby
represents and warrants to the Banks, the Co-Agents and the Agent that (i) the
representations and warranties contained in Article IV of the Agreement (other
than the representations and warranties contained in Sections 4.04(a) and
4.04(c) thereof) are correct on and as of the date hereof as though made on and
as of the date hereof, with this Amendment and the Agreement as amended hereby,
constituting "Financing Documents" for purposes thereof, and (ii) no event has
occurred and is continuing which constitutes a Default or an Event of Default.

                 3.6.  Default.  Without limiting any other event which may
constitute an Event of Default, in the event that any representation or
warranty set forth herein shall be incorrect or misleading in any material
respect when made, such event shall constitute an "Event of Default" under the
Agreement, as amended hereby.

                 IN WITNESS WHEREOF, the parties hereto have caused this
Amendment to be executed by their respective officers thereunto duly
authorized, as of the date first above written.

                                           UNION TEXAS PETROLEUM HOLDINGS, INC.


                                           By:  /s/ M.N. MARKOWITZ        
                                               ---------------------------------
                                                    M.N. Markowitz
                                                    Vice President and Treasurer


BANKS:

NATIONSBANK OF TEXAS, N.A.                 BANK OF AMERICA NATIONAL TRUST 
                                           AND SAVINGS ASSOCIATION

By:  /s/ PAUL A. SQUIRES                   By:   /s/ LAURA B. SHEPARD
    ------------------------------             --------------------------------
     Paul A. Squires                             Authorized Officer
     Senior Vice President






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UNION BANK OF SWITZERLAND,                           MELLON BANK, N.A.
HOUSTON AGENCY


By:  /s/ EVANS SWANN                                 By:    /s/ A. J. SABATELLE
    ------------------------                             ----------------------
     Evans Swann                                      
     Managing Director                                      Authorized Officer
                             
                             
By:  /s/ DAN O. BOYLE        
    ------------------------                                                   
     Dan O. Boyle        
     Vice President      
                                                     

THE BANK OF NOVA SCOTIA                              MORGAN GUARANTY TRUST
                                                     COMPANY OF NEW YORK


By:    /s/ [Illegible]                               By:    /s/ JOHN KOWALCZUK
    ------------------------                             ----------------------
      Authorized Officer                                    Authorized Officer


CHEMICAL BANK                                        BANQUE NATIONALE DE PARIS,
                                                     HOUSTON AGENCY


By:    /s/ [Illegible]                               By:    /s/ [Illegible] 
    ------------------------                             ----------------------
      Authorized Officer                                    Authorized Officer


CREDIT LYONNAIS CAYMAN                               LTCB TRUST COMPANY
ISLAND BRANCH


By:    /s/ XAVIER RATOUIS                            By:    /s/ [Illegible] 
    ------------------------                             ----------------------
      Authorized Officer                                    Authorized Officer


THE FIRST NATIONAL BANK OF                           SOCIETE GENERALE, SOUTHWEST
CHICAGO                                              AGENCY


By:    /s/ [Illegible]                               By:    /s/ [Illegible] 
    ------------------------                             ----------------------
      Authorized Agent                                      Authorized Officer


                                                     THE BANK OF TOKYO, LTD.,
                                                     DALLAS AGENCY


                                                     By:   /s/ JOHN M. MCINTYRE
                                                         ----------------------
                                                            Authorized Officer






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BANQUE PARIBAS, HOUSTON                           THE MITSUBISHI TRUST &
AGENCY                                            BANKING CORPORATION
                                    
                                    
By:   /s/ [Illegible]                             By:    /s/ [Illegible]       
    ------------------------                          ----------------------
      Authorized Officer                                 Authorized Officer
                                    
                                    
By:    /s/ BART SCHOUEST
    ------------------------                                                
      Authorized Officer                                                    

                                                  
                                    
CHRISTIANIA BANK                                  NATIONAL WESTMINSTER BANK
                                                  PLC (NEW YORK BRANCH)
                                    
                                    
By:    /s/ JAHN O. ROISING                        By:    /s/ [Illegible]       
    ------------------------                          ----------------------
      Authorized Officer                                 Authorized Officer
                                    
                                    
By:    /s/ [Illegible]                            
    ------------------------                                                
      Authorized Officer                                                    
                                                  
                                    
CITIBANK, N.A.                                    NATIONAL WESTMINSTER BANK
                                                  PLC (NASSAU BRANCH)
                                    
                                    
By:  /s/ BARBARA A. COHEN                         By:    /s/ [Illegible]       
    ------------------------                          ----------------------
     Barbara A. Cohen                                    Authorized Officer
     Vice President                                                   
                                                         
                                    
DRESDNER BANK AG, NEW YORK                        THE YASUDA TRUST AND BANKING
AND GRAND CAYMAN BRANCHES                         COMPANY, LIMITED, NEW YORK
                                                  BRANCH
                                    
                                    
By:    /s/ [Illegible]                            By:    /s/ GERARD GILL
    ------------------------                          ----------------------
      Authorized Officer                                 Authorized Officer
                                    
                                                  
By:    /s/ B. C. ERICKSON
    ------------------------                                                
      Authorized Officer                                                    
                                                  
                                                  BANK OF TAIWAN
                                    
                                    
                                                  By:    /s/ [Illegible]       
                                                      ----------------------
                                                         Authorized Officer
                                    
                                    
                                    


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BANQUE FRANCAISE DU                              DEN NORSKE BANK AS
COMMERCE EXTERIEUR                  
                                    
                                    
By: /s/ IAIN A. WHYTE                            By: /s/ EDWARD L. METE
    ------------------------                         ------------------------
    Iain A. Whyte                                    Edward L. Mete
    Assistant Vice President                         Senior Vice President
                                                     
                                    
By: /s/ MARK A. HARRINGTON                       By: /s/ FRAN MEYERS        
    ------------------------                         ------------------------ 
    Mark A. Harrington                               Fran Meyers        
    Vice President &                                 Vice President      
    Regional Manager                                               
                                              
                                    
                                                 FIRST INTERSTATE BANK OF
                                                 TEXAS, N.A.
                                    
                                    
                                                 By: /s/ COLLIE C. MICHAELS
                                                     ------------------------
                                                     Authorized Officer
                                           
                                           
                                           
                                                 NATIONSBANK OF TEXAS, N.A., 
                                                 as Agent
                                           
                                           
                                                 By: /s/ PAUL A. SQUIRES
                                                     ------------------------
                                                     Paul A. Squires
                                                     Senior Vice President
                                           
                                           
                                    
BANK OF AMERICA NATIONAL                         UNION BANK OF SWITZERLAND, 
TRUST AND SAVINGS                                HOUSTON AGENCY, as Co-Agent
ASSOCIATION, as Co-Agent            
                                    
                                    
By: /s/ LAURA B. SHEPARD                         By: /s/ EVANS SWANN         
    ------------------------                         ------------------------ 
    Authorized Officer                               Evans Swann        
                                                     Managing Director     
                                                                              
                                                                              
                                                 By: /s/ DAN O. BOYLE        
                                                     ------------------------ 
                                                     Dan O. Boyle        
                                                     Vice President      
                                    
                                    
                                    
                                    
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                                                                       EXHIBIT A

                          ACKNOWLEDGEMENT AND CONSENT
                                 June 16, 1995

                 Reference is made to the Amended and Restated Credit Agreement
dated as of May 13, 1994, as amended by the First Amendment Agreement dated as
of November 21, 1994, the Second Amendment Agreement dated as of January 31,
1995, and the Third Amendment Agreement dated as of April 24, 1995 (as so
amended, the "Credit Agreement"), among Union Texas Petroleum Holdings, Inc., a
Delaware corporation ("Company"), the Banks and Co-Agents parties thereto, and
NationsBank of Texas, N.A., as Agent ("Agent") and to the Fourth Amendment
Agreement dated as of June 16, 1995 (the "Amendment") among the Company, the
Banks and Co-Agents parties thereto, and the Agent.  Undefined capitalized
terms are used herein as defined in the Credit Agreement as amended by the
Amendment (the "Amended Credit Agreement").

                 To induce the Agent and the Banks to execute the Amendment,
each of the undersigned Subsidiary Guarantors hereby (a) acknowledges the
execution, delivery and performance of the Amendment by the Company, (b) agrees
that (i) none of such Subsidiary Guarantor's obligations under or in connection
with the Subsidiary Guaranty Agreement and none of the Banks' or the Agent's
rights and remedies with respect to any Subsidiary Guarantor is released,
impaired or affected thereby or by the foregoing, (ii) the Subsidiary Guaranty
Agreement is not released, impaired or affected thereby or by any of the
foregoing, and (iii) this acknowledgement shall not be construed as requiring
the consent or agreement of any Subsidiary Guarantor in any circumstance, (c)
ratifies and confirms all provisions of the Subsidiary Guaranty Agreement, and
(d) agrees that none of such Subsidiary Guarantor's obligations, none of the
Banks' or the Agent's rights and remedies nor the Subsidiary Guaranty
Agreement, would be released, impaired or affected if such Subsidiary Guarantor
had not executed this Acknowledgment and Consent.

                 IN WITNESS WHEREOF, the parties hereto have caused this
Acknowledgement and Consent to be duly executed and delivered by their
respective officers thereunto duly authorized, as of the 16th day of June,
1995.


SUBSIDIARY GUARANTORS:

UNION TEXAS PETROLEUM ENERGY                     UNION TEXAS PRODUCTS 
CORPORATION                                      CORPORATION          
                                                                      
                                                 

By:                                              By:          
    -----------------------                          -------------------
     M.N. Markowitz                                    M.N. Markowitz
     Treasurer                                         Treasurer






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                                                                       EXHIBIT A

UNION TEXAS EAST KALIMANTAN                      UNION TEXAS INTERNATIONAL 
LIMITED                                          CORPORATION               
                                                                           
                                                 

By:                                              By:          
    -----------------------                          -----------------------
     M.N. Markowitz                                    M.N. Markowitz
     Treasurer                                         Treasurer


                                                 UNISTAR, INC.


                                                 By:          
                                                     ------------------------
                                                       M.N. Markowitz
                                                       Vice President







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