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
Prestige oil spill a rupture and quickly release much of the remaining oil and create another catastrophic spill. The report urged the government to take "prompt" action. Experts predicted marine life could suffer from the pollution for at least ten years due to the type of oil spill, which contained light fractions with polyaromatic hydrocarbons and could poison plankton, fish eggs and crustaceans with carcinogenic effects in fish and potentially humans as well. In the subsequent months, thousands of volunteers joined the public company TRAGSA (the firm chosen by the regional government to deal with the cleanup) to help clean the affected coastline.