Deepwater Horizon oil spill 17 of whom were treated for injuries. The Deepwater Horizon sank on the morning of 22 April 2010. The oil leak was discovered on the afternoon of 22 April 2010 when a large oil slick began to spread at the former rig site. The oil flowed for 87 days. BP originally estimated a flow rate of . The Flow Rate Technical Group (FRTG) estimated the initial flow rate was . The total estimated volume of leaked oil approximated with plus or minus 10% uncertainty, including oil that was collected, making it the world's largest accidental spill. BP challenged the higher
Volume and extent of the Deepwater Horizon oil spill silts and sands onshore. On 26 May 2011, the Louisiana Department of Environmental Quality extended the state of emergency related to the spill. In April 2012, oil was found dotting of Louisiana's coast. As of December 2012, of coastline remain subject to evaluation and/or cleanup operations. On 15 May 2010, researchers from the National Institute for Undersea Science and Technology, aboard the research vessel "RV Pelican", identified oil plumes in the deep waters of the Gulf of Mexico, including one as large as long, wide and thick in spots. The shallowest oil plume the group detected was at about ,