EXHIBIT 10.2
      
                                    SECOND AMENDMENT

                                          TO

                                GROUND LEASE AGREEMENT

                                        between
                               BRAZOS RIVER LEASING L.P.

                                         and

                    DIAMOND SHAMROCK REFINING AND MARKETING COMPANY

                              Dated as of April 23, 1994



     This Second Amendment to Ground Lease Agreement has been manually
executed in 8 counterparts, numbered consecutively from 1 through 8, of which
this is No. ____.  To the extent, if any, that this Second Amendment to
Ground Lease Agreement constitutes chattel paper (as such term is defined in
the Uniform Commercial code as in effect in any jurisdiction), no security
interest in this Second Amendment to Ground Lease Agreement may be created or
perfected through the transfer or possession of any counterpart other than
the original counterpart which shall be the counterpart identified
as counterpart No. 1.


                      SECOND AMENDMENT TO GROUND LEASE AGREEMENT


     This Second Amendment to Ground Lease Agreement is made and entered     
into as of April 23, 1994, by and between BRAZOS RIVER LEASING L.P.     
("Brazos") and DIAMOND SHAMROCK REFINING AND MARKETING COMPANY ("Diamond     
Shamrock R & M").

                                W I T N E S S E T H:

     WHEREAS, Brazos and Diamond Shamrock R & M have heretofore entered into
a Ground Lease Agreement, dated as of April 23, 1992 (as amended by the First
Amendment to Ground Lease Agreement dated as of August 1, 1992, referred to
herein together as the "Ground Lease Agreement"); and

     WHEREAS, Brazos and Diamond Shamrock R & M desire to amend the Ground 
Lease Agreement to extend the lease term and to otherwise set forth their
mutual agreement; and

     WHEREAS, Brazos and Diamond Shamrock R & M agree that the provisions of
this amendment shall apply, to the extent provided by law, to each Property
hereafter leased by Brazos under the Ground Lease Agreement.

     NOW, THEREFORE, in consideration of the mutual covenants herein
contained and other valuable consideration, the receipt and sufficiency of
which are hereby acknowledged, Brazos and Diamond Shamrock R & M agree that
the Ground Lease Agreement is hereby amended as follows:

     1.   Section 5.01 of the Ground Lease Agreement is hereby amended by
deleting the reference to "five years" and inserting in lieu thereof "seven  
years".

     2.   Section 5.02 of the Ground Lease Agreement is hereby amended by
deleting the reference to "2007" and inserting in lieu thereof "2009".

     3.   Brazos and Diamond Shamrock R & M agree that this Second Amendment
to Ground Lease Agreement shall not be effective until the approvals required
by Section 9.01 of the Credit Agreement have been obtained as evidenced by
the execution of Amendment No. 2 by the necessary parties under the Credit
Agreement.

     4.   Defined terms used in this Second Amendment to Ground Lease
Agreement and not otherwise defined herein have the meanings ascribed to
those terms in the Ground Lease Agreement.

     IN WITNESS WHEREOF, Brazos and Diamond Shamrock R & M have caused this 
Second Amendment to Ground Lease Agreement to be executed and delivered by
their duly authorized officers as of the day and year first above written.

                                        BRAZOS RIVER LEASING L.P.

                                        By:  Headwater Investments L.P.,
                                             its General Partner

                                             By:  Headwater Holdings, Inc.,
                                                  its General Partner


                                             By:____________________________
                                                  Gregory C. Greene,
                                                     President



                                        DIAMOND SHAMROCK REFINING AND
                                             MARKETING COMPANY



                                        By: /S/ R.C. BECKER
                                        Name:   R.C. Becker
                                        Title:  Vice President and
                                                  Treasurer