Exxon Valdez oil spill a number of recommendations, such as changes to the work patterns of Exxon crew in order to address the causes of the accident. In response to the spill, the United States Congress passed the Oil Pollution Act of 1990 (OPA). The legislation included a clause that prohibits any vessel that, after March 22, 1989, has caused an oil spill of more than in any marine area, from operating in Prince William Sound. In April 1998, the company argued in a legal action against the Federal government that the ship should be allowed back into Alaskan waters. Exxon claimed OPA was
Exxon Valdez oil spill effectively a bill of attainder, a regulation that was unfairly directed at Exxon alone. In 2002, the 9th Circuit Court of Appeals ruled against Exxon. As of 2002, OPA had prevented 18 ships from entering Prince William Sound. OPA also set a schedule for the gradual phase in of a double hull design, providing an additional layer between the oil tanks and the ocean. While a double hull would likely not have prevented the "Valdez" disaster, a Coast Guard study estimated that it would have cut the amount of oil spilled by 60 percent. The "Exxon Valdez" supertanker was towed