Workers wash the shoreline on Latouche Island, Alaska, after the Exxon Valdez oil tanker ran aground in 1989, dumping more than 38 million liters (more than 10 million gallons) of oil into Prince William Sound. The resulting environmental damage prompted the United States Congress to pass federal safety requirements for oil tankers and barges and to assign the principal cost of spill cleanup to oil companies.
Tankers of all kinds carry potentially dangerous cargo, and a few have caused environmental disasters of tragic proportions.
The 1967 wreck of the oil tanker Torrey Canyon devastated the marine environment off the coast of Great Britain. In 1989 the American oil tanker Exxon Valdez ran aground in Prince William Sound, Alaska, eventually coating 1,770 km (1,100 mi) of the Alaskan coastline with deadly crude oil. These and other devastating oil spills have led to international discussions about whether to institute regulations requiring that oil tankers have double hulls. In particularly sensitive areas, regional governments may require that small local pilot boats captained by sailors familiar with underwater topography accompany tankers when they reach coastal waters.