UDS Starts Up New Propylene Splitter Unit

Business Wire, August 31, 1998

SAN ANTONIO--(BUSINESS WIRE)--Aug. 31, 1998--Ultramar Diamond Shamrock Corporation's (NYSE:UDS) third propylene splitter at Mont Belvieu, Texas, successfully came on line Aug. 21, with on-spec product available Aug. 22.

The new splitter has the capacity to produce one billion pounds per year of polymer grade propylene. The addition of the third splitter and a planned expansion next year for the existing two splitters will increase Mont Belvieu's total propylene production capacity to three billion pounds per year.

Mike Milam, UDS vice president of petrochemicals, specialty products and energy, commented, "The Mont Belvieu team has done an excellent job of completing this project on time and under budget. The new unit is a state-of-the-art splitter that will enable UDS to better serve our customers."

Ultramar Diamond Shamrock Corp., with about $12 billion in annual revenues, is one of the largest independent petroleum refining and petroleum product and convenience merchandise marketing companies in North America. The corporation owns seven refineries in the United States and Canada with a total throughput capacity of 680,000 barrels per day and has approximately 6,100 branded retail gasoline/convenience merchandise stores, the majority of which are branded Diamond Shamrock, Ultramar, Beacon or Total. The corporation also has growing petrochemicals and home heating oil businesses.

Statements contained in this news release that state the company's or management's expectations or predictions of the future are forward-looking statements intended to be covered by the Safe Harbor provisions of the Securities Act of 1933 and the Securities Exchange Act of 1934. It is important to note that should the assumptions underlying such statements change, the company's actual results could differ materially from those projected. The company disclaims any obligation to update forward-looking statements contained in this news release.

    CONTACT: Ultramar Diamond Shamrock Corporation, San Antonio
              Mary Hartman, 210/592-4469