The Deepwater Horizon Oil Spill began on April 20, 2010, in the Gulf of Mexico on the BP-operated Macondo Prospect. 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 July 15, 2010. Eleven people went missing and were never found and it 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.
Source: https://en.wikipedia.org/wiki/Deepwater_Horizon_oil_spill