EXHIBIT 24.2 POWER OF ATTORNEY The undersigned directors and/or officers of Diamond Shamrock, Inc., hereby constitute and appoint Timothy J. Fretthold, Jerry D. King and Todd Walker, or any of them, their true and lawful attorneys-in-fact and agents, each with full power of substitution and resubstitution, to do any and all acts and things in their name and behalf in their capacity as a director and/or officer of Diamond Shamrock, Inc. and to execute any and all instruments for them and in their name in such capacity, which said attorneys-in-fact and agents, or any of them, may deem necessary or advisable to enable Diamond Shamrock, Inc. to comply with the Securities Exchange Act of 1934, as amended, and any rules, regulations and requirements of the Securities and Exchange Commission, in connection with the Annual Report on Form 10-K of Diamond Shamrock, Inc. for the fiscal year ended December 31, 1994, including without limitation, power and authority to sign for them, in their name in the capacity indicated above, such Form 10-K and any and all amendments thereto, and to file the same, with all exhibits thereto, and other documents in connection therewith, with the Securities and Exchange Commission, hereby ratifying and confirming all that the said attorneys-in-fact and agents, or their substitute or substitutes, or any one of them, shall do or cause to be done by virtue hereof. /S/ R. R. HEMMINGHAUS /S/ E. GLENN BIGGS R. R. Hemminghaus E. Glenn Biggs Chairman of the Board and Director Chief Executive Officer /S/ ROBERT C. BECKER /S/ WILLIAM E. BRADFORD Robert C. Becker William E. Bradford Vice President and Treasurer Director /S/ GARY E. JOHNSON /S/ LAURO F. CAVAZOS Gary E. Johnson Lauro F. Cavazos Vice President and Controller Director /S/ B. CHARLES AMES /S/ W. H. CLARK B. Charles Ames W. H. Clark Director Director /S/ WILLIAM L. FISHER /S/ BOB MARBUT William L. Fisher Bob Marbut Director Director /S/ KATHERINE D. ORTEGA Katherine D. Ortega Director Dated: February 7, 1995