Efforts to stem the Deepwater Horizon oil spill Efforts to stem the Deepwater Horizon oil spill Efforts to stem the "Deepwater Horizon" oil spill were ongoing from the time that the "Deepwater Horizon" exploded on 4/20/2010 until the well was sealed by a cap on July 15, 2010. Various species of dolphins and other mammals (61 casualties), birds (2,095 casualties), and the endangered sea turtles (467 casualties) have been killed either directly or indirectly by the oil spill. The "Deepwater Horizon" spill has surpassed in volume the 1989 "Exxon Valdez" oil spill as the largest ever to originate in U.S.-controlled waters; it is comparable to the 1979 Ixtoc
1969 Santa Barbara oil spill which devastated coastal areas in both England and France, and the burning of the Cuyahoga River in downtown Cleveland, Ohio. At the time, the Santa Barbara spill was the largest oil spill ever in U.S. waters, and its occurrence during a fierce battle between local residents and the very oil company responsible for the spill only made the controversy more intense, the battle more public, and the anti-oil cause seem more valid to a wider segment of the populace. In the several years after the spill, more environmental legislation was passed than in any other similar period in U.S. history.