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                                                                   EXHIBIT 10.3

                               THIRD AMENDMENT TO
                      UNION TEXAS PETROLEUM HOLDINGS, INC.
                             1992 STOCK OPTION PLAN


         WHEREAS, UNION TEXAS PETROLEUM HOLDINGS, INC. (the "Company") has
heretofore adopted the UNION TEXAS PETROLEUM HOLDINGS, INC. 1992 STOCK OPTION
PLAN (the "Plan"); and

         WHEREAS, subsequent thereto, the Company has amended the Plan; and

         WHEREAS, the Company desires to amend the Plan in certain respects;

         NOW THEREFORE, the Plan shall be amended as follows, effective May 9,
1997:

         1.      Paragraph IV shall be amended by adding the term "Except as
provided below," at the beginning of the first sentence, by adding "or pursuant
to a qualified domestic relations order as determined by the Committee" at the
end of the first sentence and by adding the following after the first sentence
of such Section:

         "The Committee may, in its discretion, adopt rules or guidelines under
         which any Option  (other than an Option intended to constitute an
         Incentive Stock Option so long as transferability of an Incentive
         Stock Option is prohibited by the Code) previously granted to an
         Optionee may be transferred (in whole or in part pursuant to such form
         as approved by the Company) by the Optionee to (i) the spouse,
         children or grandchildren of the Optionee ("Immediate Family
         Members"), (ii) a trust or trusts for the exclusive benefit of the
         Immediate Family Members and, if applicable, the Optionee, (iii) a
         partnership, limited liability company or other entity in which such
         Immediate Family Members and, if applicable, the Optionee are the only
         partners, members or stockholders, (iv) the transferee pursuant to a
         qualified domestic relations order as determined by the Committee, (v)
         an organization described under Section 501(c)(3) of the Code and
         which is a private foundation within Section 509(a) of the Code or any
         trust the only beneficiary (other than an Immediate Family Member and,
         if applicable, the Optionee) of which is an organization described
         under Section 501(c)(3) of the Code and which organization is a
         private foundation within Section 509(a) of the Code or (vi) to other
         persons or entities as approved by the Board or the Committee in its
         discretion.  Following transfer, any such Option shall continue to be
         subject to the same terms and conditions as were applicable to the
         Option immediately prior to transfer; provided, however, that no
         transferred Option shall be exercisable or payable, as the case may
         be, unless arrangements satisfactory to the Company have been made to
         satisfy any tax withholding obligations the Company may have with
         respect to the Option."

         2.      Paragraph VIII shall be amended by adding the term "Except as
provided in Paragraph IV," at the beginning of the first sentence of such
Section and by adding the
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following phrase ", which arrangement in the discretion of the Committee may
include the relinquishment of a portion of the shares subject to the Option or
delivery of shares of Stock owned by the Optionee" to the end of Paragraph
VIII(b), before the last word "and".

         3.      As amended hereby, the Plan is specifically ratified and
reaffirmed.

         IN WITNESS WHEREOF, this Third Amendment has been executed this 9th
day of May, 1997.

                                      UNION TEXAS PETROLEUM HOLDINGS, INC.



                                      By: /s/ J. L. WHITMIRE                  
                                         -------------------------------------
                                          J. L. Whitmire
                                          Chairman and Chief Executive Officer

ATTEST:



/s/ LINDA L. MEAGHER                       
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L. L. Meagher
Assistant Secretary