The Exxon Valdez oil spill was not a large one in relation to the world's biggest oil spills, but it was a costly one due to the remote location of Prince William Sound (accessible only by helicopter and boat). On March 24, 1989, 10.8 million gallons of oil was spilled when the ship's master, Joseph Hazelwood, left the controls and the ship crashed into a Reef. The cleanup cost Exxon $2.5 billion.