One of the worst oil spills in U.S. territory begins when the supertanker Exxon Valdez, owned and operated by the Exxon Corporation, runs aground on a reef in Prince William Sound in southern Alaska. An estimated 11 million gallons of oil eventually spilled into the water. Attempts to contain the massive spill were unsuccessful, and wind and currents spread the oil more than 100 miles from its source, eventually polluting more than 700 miles of coastline. Hundreds of thousands of birds and animals were adversely affected by the environmental disaster.