Sep 27, 2001

Premcor Inc., Files Registration Statement for Initial Public Offering

ST. LOUIS, September 27, 2001---Premcor Inc. announced today that it has filed a registration statement with the U.S. Securities and Exchange Commission in connection with a proposed initial public offering of a new issue of its common stock.

Morgan Stanley & Co. Incorporated will be the sole book-running managing underwriter of the offering.

Premcor Inc., through its principal operating subsidiaries, The Premcor Refining Group Inc. and The Port Arthur Coker Company, L.P., is one of the largest independent petroleum refiners and marketers of unbranded transportation fuels, heating oil, petrochemical feedstocks, petroleum coke and other petroleum products in the United States. The company has an aggregate 490,000 barrels per day (bpd) of crude distillation capacity at its three refineries located in Port Arthur, Texas (250,000 bpd), Lima, Ohio (170,000 bpd) and Hartford, Illinois (70,000 bpd).

A registration statement relating to these securities has been filed with the Securities and Exchange Commission but has not yet become effective. These securities may not be sold nor may offers to buy be accepted prior to the time the registration statement becomes effective. This press release shall not constitute an offer to sell or the solicitation of an offer to buy nor shall there be any sale of these securities in any state in which such offer, solicitation or sale would be unlawful prior to registration or qualification under the securities laws of any such state.

When available, a copy of the preliminary prospectus relating to the offering may be obtained from Morgan Stanley & Co. Incorporated, attention: Prospectus Department, 1585 Broadway, New York, NY 10036, 212-761-8570.