|Fate||Merged with Phillips Petroleum (ConocoPhillips)|
|Founded||1955 in Santa Monica, California|
Tosco (The Oil Shale COrporation) was an independent US based petroleum refining and marketing corporation. It was founded in 1955 in Santa Monica, California by A&P heir Huntington Hartford, and originally focused on extracting oil from oil shale and developing alternative energy sources.
In 1964 Tosco, Standard Oil of Ohio, and Cleveland Cliffs Iron Company formed Colony Development, a joint venture company to develop the Colony Oil Shale Project in Colorado and to commercialize the TOSCO II technology. In 1969, ARCO joined the project. The project was ended in April 1972.
In 1976 the company name was shortened to Tosco after the company acquired the Avon Refinery in Martinez, California, and other west coast facilities from Phillips Petroleum, making it a major player in petroleum refining. The company continued its efforts in oil shale extraction until May 2, 1982 when Exxon (which had bought Atlantic Richfield's 60% share in the project in 1980) pulled out of the Colony Project joint venture, leaving Tosco unable to keep the venture viable in spite of a $1.1 million loan guarantee from the U.S. government. Exxon claimed the project's projected $6 billion price tag made the project no longer feasible, but Exxon was required to purchase Tosco's 40% share in the project as a result of their withdrawal.
A major company reorganization followed in 1983. Several takeover bids during the 1980s failed to materialize, and another major reorganization took place in 1991 with the company moving its headquarters to Stamford, Connecticut.
Mergers and acquisitions
In 1996, Tosco acquired the Circle K chain of convenience stores. In 1997, Tosco bought the rights to the Union 76 brand of gas stations and the western United States refining and marketing operations from Unocal. Tosco merged with Phillips Petroleum in 2001. Phillips merged with Conoco in 2002 to become ConocoPhillips, who spun off the Circle K stores to Canadian-based Alimentation Couche-Tard.
1999 refinery accident
On February 23, 1999, four workers at the Avon Refinery in Concord were burned to death after they tried to replace a leaky oil pipe. The San Francisco Chronicle reported  that one Tosco employee, Anthony Creggett, claimed shortly after the fire that plant managers had refused a request by four workers to shut down the high-temperature distillation tower during the repairs on the pipe.
- "An Assessment of Oil Shale Technologies" (PDF). June 1980. NTIS order #PB80-210115. Retrieved 2008-11-23.
- Standard Reference Encyclopedia Yearbook: Events of 1982, page 155. New York: Funk & Wagnalls, 1983.
- Tosco Corporation: Information and Much More from Answers.com
- "Tosco completes merger with Phillips. (Top of the News)". National Petroleum News.[dead link]
- "Philips Petroleum Co. to purchase the Tosco Corp. for 0.52 times revenue, The". Weekly Corporate Growth Report. 2001.