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
1989 Narragansett Bay oil spill 1989 Narragansett Bay oil spill On June 23, 1989, several hundred thousand gallons of fuel oil were spilled at the mouth of the Narragansett Bay in Rhode Island after the tanker MV "World Prodigy" ran aground on a reef near Aquidneck Island. "World Prodigy", a long ship operated by Ballard Shipping under the Greek flag, was inbound to Providence and Tiverton, Rhode Island when at about 16:40 local time she ran aground on Brenton Reef, about offshore from Brenton Point State Park, after passing the wrong side of a buoy marking the channel. She had a cargo of about 8.1