The Deepwater Horizon oil spill (also referred to as the BP oil spill, the BP oil disaster, the Gulf of Mexico oil spill, and the Macondo blowout) began on 20 April 2010 in the Gulf of Mexico on the BP-operated Macondo Prospect. It claimed eleven lives and is considered the largest accidental marine oil spill in the history of the petroleum industry, an estimated 8% to 31% larger in volume than the previously largest, the Ixtoc I oil spill. Following the explosion and sinking of the Deepwater Horizon oil rig, a sea-floor oil gusher flowed for 87 days, until it was capped on 15 July 2010. The US Government estimated the total discharge at 4.9 million barrels (210 million US gal; 780,000 m3). After several failed efforts to contain the flow, the well was declared sealed on 19 September 2010. Some reports indicate the well site continues to leak.
A massive response ensued to protect beaches, wetlands and estuaries from the spreading oil utilizing skimmer ships, floating booms, controlled burns and 1.84 million US gallons (7,000 m3) of Corexit oil dispersant. Due to the months-long spill, along with adverse effects from the response and cleanup activities, extensive damage to marine and wildlife habitats and fishing and tourism industries were reported. In Louisiana, 4.6 million pounds of oily material was removed from the beaches in 2013, over double the amount collected in 2012. Oil cleanup crews worked four days a week on 55 miles of Louisiana shoreline throughout 2013. Oil continued to be found as far from the Macondo site as the waters off the Florida Panhandle and Tampa Bay, where scientists said the oil and dispersant mixture is embedded in the sand. In 2013 it was reported that dolphins and other marine life continued to die in record numbers with infant dolphins dying at six times the normal rate. One study released in 2014 reported that tuna and amberjack that were exposed to oil from the spill developed deformities of the heart and other organs that would be expected to be fatal or at least life-shortening and another study found that cardiotoxicity might have been widespread in animal life exposed to the spill.