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
Australian Marine Oil Spill Centre 24-hour stand-by. The AMOSplan is voluntary mutual aid arrangement where oil company equipment may be shared to best respond to a spill. AMOSplan replaced the former Marine Oil Spills Action Plan (MOSAP). The MOSAP was activated when an oil spill became too large for an individual company to adequately deal with. Integration with government responses to spills is framed within the National Plan to Combat Pollution of the Sea by Oil, which is managed by the Australian Maritime Safety Authority. In 2009, AMOSC responded to the Montara oil spill in the Timor Sea by mobilising aircraft and dispersant for aerial