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
Xingang Port oil spill at the port began, triggering a fire which subsequently burned for 15 hours. The fire burned from oil that was released from a filled storage tank with a 90,000 ton capacity that collapsed as a result of the fire. Oil from other nearby tanks was, according to a Greenpeace report released several weeks after the incident, intentionally released to prevent the fire from expanding towards a tank containing dimethylbenzene, a flammable chemical. Although Chinese government officials reported that as little as 1,500 tonnes of oil spilled, a former University of Alaska marine conservation specialist, Rick Steiner, estimates the spill to