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
Oil tanker has a capacity of over , a length overall of and a cargo capacity of . They were the first ULCCs to be double-hulled. To differentiate them from smaller ULCCs, these ships are sometimes given the "V-Plus" size designation. With the exception of the pipeline, the tanker is the most cost-effective way to move oil today. Worldwide, tankers carry some annually, and the cost of transportation by tanker amounts to only US$0.02 per gallon at the pump. In 1954 Shell Oil developed the average freight rate assessment (AFRA) system which classifies tankers of different sizes. To make it an independent