Exxon Valdez oil spill occurred in Prince William Sound, Alaska, on March 24, 1989, when the Exxon Valdez, an oil tanker bound for Long Beach, California, hit Prince William Sounds Bligh Reef and spilled (oil spill) a widely reported estimate of 10.8 million US gallons (40.9 million liters, or 250,000 barrels) of crude oil. Others estimate the total was closer to 30 million gallons.cite weburl=19, 2010 title=Size of Exxon spill remains disputed publisher=Anchorage Daily News It is considered to be one of the most devastating human-caused environmental disasters ever to occur in history. As significant as the Valdez spill was ? the largest ever in U.S. waters until the 2010 Deepwater Horizon oil spill (Deepwater Horizon oil spill) ? it ranks well down on the list of the worlds largest oil spill (Oil_spills#Largest_oil_spills)s in terms of volume released. However, Prince William Sounds remote location (accessible only by helicopter, plane and boat) made government and industry response efforts difficult and severely taxed existing plans for response. The region is a habitat for salmon, sea otters, seals (Pinniped) and seabirds. The oil, originally extracted at the Prudhoe Bay oil field, eventually covered convert1300mikm of coastline and convert11000sqmikm2 of ocean.