EXHIBIT 99.1


                                                                   [TESORO LOGO]

FOR IMMEDIATE RELEASE

CONTACT:
         INVESTORS:
         JOHN ROBERTSON, DIRECTOR, INVESTOR RELATIONS, (210) 283-2687

         MEDIA:
         TARA FORD, DIRECTOR, PUBLIC RELATIONS, (210) 283-2676


                   TESORO PETROLEUM SIGNS DEFINITIVE AGREEMENT
                TO SELL PRODUCT PIPELINE FOR $110 MILLION IN CASH


         SAN ANTONIO - AUGUST 26, 2002 - Tesoro Petroleum Corporation (NYSE:TSO)
today announced that the company has signed an Asset Purchase Agreement with
Williams Energy Partners L.P. (NYSE: WEG) to sell its Northern Great Plains
Products System for $110 million in cash. The system includes a product pipeline
from Mandan, N.D., to Minneapolis and terminals in Jamestown and Moorhead, North
Dakota, Sauk Centre and Roseville (Twin Cities), Minnesota. The transaction will
require regulatory approval and is expected to close in mid-October.

         The purchase agreement excludes Tesoro's Mandan refinery and terminal,
a crude-gathering system in western North Dakota and a network of retail
outlets.

         "We believe the sale of these assets will enhance our ability to access
new customers and markets by providing increased logistics flexibility which
will permit us to capture new synergies," said Bruce A. Smith, Chairman,
President and CEO of Tesoro. "The sale to Williams Energy Partners L.P. gives
our shareholders two benefits; first, we will be able to improve Mandan's
flexibility and second, the sale demonstrates our commitment to our stated goal
to reduce debt by raising $200 million this year by selling assets," added
Smith.






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Tesoro Signs Definitive Agreement


         Proceeds from the sale will be used to pay down a portion of the
company's bank debt and for general corporate purposes. The company estimates
the earnings before interest, taxes, depreciation and amortization from the
asset sold to be in the range of $12-13 million annually before synergies.

         Tesoro Petroleum Corporation, a Fortune 500 Company, is an independent
refiner and marketer of petroleum products and provider of marine logistics
services. Tesoro operates six refineries in the western United States with a
combined capacity of nearly 560,000 barrels per day. Tesoro's growing
retail-marketing system includes nearly 750 branded retail stations, of which
over 290 are company owned under the Tesoro(R) and Mirastar(R) brands.

         This news release contains certain statements that are
"forward-looking" statements within the meaning of Section 27A of the Securities
Act of 1933 and Section 21E of the Securities Exchange Act of 1934. These
forward-looking statements contain expectations with respect to our debt
reduction goals and expected benefits from the sale of the Northern Great Plains
Product System. For more information concerning factors that could cause actual
results to differ from expectations, see the company's annual report on Form
10-K and quarterly reports on Form 10-Q, filed with the Securities and Exchange
Commission. The company undertakes no obligation to publicly release the result
of any revisions to any such forward-looking statements that may be made to
reflect events or circumstances that occur, or which the Company becomes aware
of, after the date hereof.

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