The Deepwater Horizon drilling rig explosion was the April 20, 2010, explosion and subsequent fire on the Deepwater Horizon semi-submersible Mobile Offshore Drilling Unit (MODU), which was owned and operated by Transocean and drilling for BP in the Macondo Prospect oil field about 40 miles (60 km) southeast off the Louisiana coast. The explosion and subsequent fire resulted in the sinking of the Deepwater Horizon and the deaths of 11 workers; 17 others were injured. The same blowout that caused the explosion also caused a massive offshore oil spill in the Gulf of Mexico, considered the largest accidental marine oil spill in the world, and the largest environmental disaster in U.S. history.
The fire aboard the Deepwater Horizon reportedly started at 9:56 p.m. CDT on April 20. At the time, 126 crew were on board: seven employees of BP, 79 of Transocean, and employees of other companies, including Anadarko, Halliburton and M-I Swaco. Transocean employees on the vessel stated that the electric lights flickered, followed by two strong vibrations. Jim Ingram stated that "on the second [thud], we knew something was wrong." After the explosion, Adrian Rose stated that abnormal pressure had accumulated inside the marine riser and as it came up it "expanded rapidly and ignited." According to BP's internal investigation, a bubble of methane gas escaped from the well and shot up the drill column, expanding quickly as it burst through several seals and barriers before exploding. Rose said the event was basically a blowout. Survivors described the incident as a sudden explosion that gave them less than five minutes to escape as the alarm went off. The explosion was followed by a fire that engulfed the platform. After burning for more than a day, Deepwater Horizon sank on April 22. The Coast Guard stated on April 22 that they received word of the sinking at approximately 10:21 am. On September 8, BP published a report that suggested that the ignition source was the released gas entering the air intakes of the diesel generators, and engulfing the deck area where the exhaust outlets for the main generators were emitting hot exhaust gas.
Initial reports indicated that between 12 and 15 workers were missing; reports soon narrowed the number of missing to nine crew members on the platform floor and two engineers. The United States Coast Guard immediately launched a massive rescue operation involving two Coast Guard cutters, four helicopters, and a rescue plane. Two of the cutters continued searching through the night. By the morning of April 22, the Coast Guard had surveyed nearly 1,940 square miles (5,000 km2). On April 23, the Coast Guard called off the search for the 11 missing persons, concluding that "reasonable expectations of survival" had passed. Officials concluded that the missing workers may have been near the blast and unable to escape the sudden explosion. The following eleven individuals died: Jason C. Anderson, age 35; Aaron Dale Burkeen, 37; Donald Clark, 49; Stephen Ray Curtis, 39; Gordon L. Jones, 28; Roy Wyatt Kemp, 27; Karl D. Kleppinger, Jr., 38; Keith Blair Manuel, 56; Dewey A. Revette, 48; Shane M. Roshto, 22; Adam Weise, 24