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 collected before it could enter the Gulf waters. In its permit to drill the well, BP estimated the worst-case flow at . Immediately after the explosion the USCG did not estimate any oil leaking from the sunken rig or from the well. On 24 April, USCG Rear Admiral Mary Landry announced that a damaged wellhead was indeed leaking. She stated that "the leak was a new discovery but could have begun when the offshore platform sank . . . two days after the initial explosion." Initial estimates by USCG and BP officials, based on remotely operated vehicles as well as