press release

Judge recuses himself in patent infringement case

El Segundo, Calif., Dec. 28, 2001 - Unocal Corporation (NYSE: UCL) today said that U.S. District Court Judge J. Spencer Letts has recused himself from the case involving infringement on the company's '393 gasoline patent due to his discovery that he had a "financial interest" in one of the parties involved in the litigation.

In an order of recusal issued December 20, Judge Letts stated, "The issue arose because of an error in the way that this financial interest was identified in my investment records and my financial disclosures." The judge did not identify the party in which he had this financial interest.

The case will be returned for reassignment in the United States District Court, Central District of California.

In October, Judge Letts had granted the company's motion for summary judgment requesting an accounting of infringement of its '393 cleaner burning gasoline patent by a group of five refiners. However, he had not issued a written judgement. Further proceedings in the case will now be considered by the new judge.

The defendants in the case are Atlantic Richfield Co. (now merged with BP), Chevron U.S.A., Inc., Texaco Refining and Marketing, Inc. (now merged with Chevron), Exxon Corporation, Mobil Oil Corporation (now merged with Exxon), and Shell Oil Products Company.

In 1997, a jury in the U.S. District Court, Central District found the Unocal patent valid and that the defendant companies had infringed on it in their refining processes. The jury awarded damages of 5.75 cents per infringing gallon. Unocal received a payment of $69 million plus accrued interest and some attorneys' fees in June 2000 for infringement from March 1, 1996, to July 31, 1996. About 29 percent of the RFG gasoline manufactured by the defendants during that period infringed on the '393 patent.

The jury decision was upheld by the Federal Circuit Court of Appeals in May 2000. In February of this year, the U.S. Supreme Court declined to hear the case.

License agreements signed with 8 companies

Unocal holds five patents on cleaner burning gasoline compositions. Unocal has signed licensing agreements with eight companies, giving them the right to produce and blend cleaner burning gasolines using Unocal's patented formulations.

Earlier this year, Unocal introduced a uniform licensing program that specifies a range of between 1.2 and 3.4 cents per gallon for volumes that fall under the Unocal patents. The licensee's rate per gallon is reduced as more utilization occurs.

Additional information about Unocal's patents for cleaner burning gasoline formulations is available on the company's website and in its 2000 Annual Report on Form 10-K and subsequent reports filed with the U.S. Securities and Exchange Commission, which can also be accessed from the company's website.

About Unocal Corporation

Unocal is one of the world's leading independent natural gas and crude oil exploration and production companies. The company's principal operations are located in North America (Gulf of Mexico region, Alaska and Canada) and in Asia (Thailand, Myanmar, Indonesia, Bangladesh and Azerbaijan). The company is also pursuing exploration programs in West Africa and Brazil.

Updated: December 2001