The "Exxon Valdez" oil spill was a shipping accident that happened off the coast of the United States on March 24, 1989. An oil tanker, the "Exxon Valdez", hit a reef in Prince William Sound, Alaska. At the time of the disaster, the ship carried 53,094,510 U.S. gallons (44,210,430 imp gal/200,984,600 L) of crude oil. The accident caused a massive oil spill: 10.8 million U.S. gallons (9.0 million imp gal/41 million L) were spilled into the Prince William Sound. It was one of the worst man-made environmental disasters in the history of the United States.