Prudhoe Bay is the largest U.S. oilfield, representing 8 percent of domestic production. BP, which controls the oil rights, began shutting down the western portion of the field after a small leak -- and extensive corrosion -- was found.
Before the shutdown, the Prudhoe Bay field had been producing 400,000 barrels of crude oil a day. BP has announced that it will try to maintain a diminished flow of oil from the field as it works to repair or replace some 16 miles of pipeline.
Located on Alaska's North Slope, the Prudhoe Bay oil field was discovered in 1968. It remains the largest oil field in North America.