thumb|right|200px|An ARCO filling station off Los Angeles/" class="wiki">Slauson Avenue in Los AngelesARCO (an acronym for Atlantic Richfield Company) is an oil company which is, since 2000, a subsidiary of UK-based BP and is officially known as BP West Coast Products LLC. ARCO that was formed by the merger of East Coast-based Atlantic Refining and California-based Richfield Petroleum in 1966. It is known for having low-priced gasoline compared with other national brands, mainly due to an early 1980s decision to emphasize cost cuts (cash only policy) and alternative sources of income (ampm). ARCO is headquartered in La Palma, California.

History

The Atlantic Petroleum Storage Company's heritage dates to 1866; it became part of the Standard Oil trust in 1874, but achieved independence again when Standard Oil was broken up in 1911. ARCO was a principal in the discovery of Prudhoe Bay, Alaska, North America's largest oil field, in 1968. Led by founder Robert Orville Anderson, ARCO acquired Sinclair Oil in 1969, but later divested certain Sinclair assets during the mid 1970s, resulting in Sinclair returning as a private company. Commercial oil exploration started in Prudhoe Bay area in the 1960s and the Prudhoe Bay field was discovered on March 12, 1968, by Atlantic Richfield Company (ARCO) and Exxon, with the well Prudhoe Bay State #1.

ARCO once had a presence in the southwestern U.S. - a stretch of Texas State Highway 225 east of Loop 610 in Houston, Texas, had an oil tank farm once painted with the ARCO logo. Lyondell-Citgo would rebrand the oil tanks in the 1980s. ARCO's Corporate Headquarters were in the ARCO Center in Los Angeles at the corner of 5th and Flower Streets before they were acquired by BP. ARCO's Oil & Gas division headquarters were in downtown Dallas, Texas. The headquarters building was a 46-story office building designed by architect I.M. Pei, the ARCO Tower. ARCO closed the Dallas office and sold the building in the mid 1980s. Today, ARCO operates about 1100 stations in 5 US Western States: California, Nevada, Oregon, Washington, and Arizona.

ARCO merged with Anaconda Copper Mining Company (ACM) of Montana in 1977. ACM holdings including the Berkeley Pit and the Anaconda, Montana Smelter. ARCO founder stated "he hoped Anaconda's resources and expertise would help him launch a major shale-oil venture, but that the world oil glut and the declining price of petroleum made shale oil moot." The purchase turned out to be a regrettable decision for ARCO. Lack of experience with hard-rock mining, and a sudden drop in the price of copper to below seventy cents a pound, the lowest in years, caused ARCO to suspend all operations in Butte, Montana. By 1983, only six years after acquiring rights to the "Richest Hill on Earth," the Berkeley Pit was completely idle. By 1986, some ARCO properties were sold to billionaire industrialist Dennis Washington, whose company Montana Resources operates a much smaller open-pit mine east of the defunct Berkeley Pit.

The Atlantic brand was spun off for ARCO's East Coast stations, and was acquired by Sunoco. The ARCO brand is now used on the West Coast. ARCO specializes in discount gas by removing many frills, among them forcing prepayment for fuel, not accepting credit cards at most locations, and charging $0.45 for use of debit cards. In most locations, it is co-branded with ampm convenience stores, also a division of BP West Coast (ARCO introduced the ampm concept in 1979).

ARCO financed EASTLUND in begin of 90's for High Auroral Active Research Project (HAARP Project)

Over the course of 2004 and 2005, ARCO signs have been replaced. New signs still have the Arco spark, but BP's Helios (BP's new white, yellow, and green mark named after the Greek sun god which replaced the old British Petroleum shield mark) is also located on the sign. A new tagline "ARCO - part of BP" has also appeared on some signs and advertisements. ARCO is known for sponsoring the ARCO Arena in Sacramento, California, with a license fee was $750,000/year through 2007.

In March, 1997, ARCO also leased almost all the gas stations of the (now) Santa Fe Springs, CA based independent Thrifty Oil group of 250 stations found throughout California after a damaging price war which the independent Thrifty was unable to win.

Superfund site

ARCO is the responsible party for America's largest Superfund site- a site that takes in the towns of Butte and Anaconda, and of the Clark Fork River including Milltown Dam. The region's water and soils were polluted by a century of mining and smelting. Chemicals of concern include many heavy metals and arsenic. On 7 February 2008, the United States Environmental Protection Agency‎ announced that prolonged litigation with ARCO ended when ARCO agreed to pay $187 million to finance natural resource restoration activities.