A growing oil spill in the Gulf of Mexico is expected to become one of the biggest oil-related environmental disasters in US history and to lead to tougher oversight from regulatory authorities. As a 120-mile (190-km) oil slick moves closer to the shoreline, a ruptured undersea well continues to spew some 5,000 barrels of crude oil a day, and it could be weeks to stop the flow. Here is a look at five major oil spills that impacted the United States, some of which had regulatory repercussions. One spilled barrel holds 42 gallons: __
