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
Exxon Valdez oil spill responsible" for the spill, because they had granted mariners' licenses to the crew of the Valdez, and because they had given the "Valdez" permission to leave regular shipping lanes to avoid ice. They also reiterated the claim that the Coast Guard had delayed cleanup by refusing to give permission to immediately use chemical dispersants on the spill. The Oil Spill Recovery Institute was formed after United States Congress approved it to seek a solution. Collaborating with InnoCentive they found a partial solution for the flow of oil. A report by the US National Response Team summarized the event and made