Scenes from the Deepwater Horizon drilling platform in the Gulf of Mexico. The BP leased, Transocean mobile offshore drilling platform was engulfed in flames after an explosion April 20 and sank in 5,000 feet of water in the Gulf of Mexico. Eleven workers died. Oil gushed from the deepwater wellhead into the Gulf of Mexico for more than 100 days until a relief well was drilled and the leaking well clogged with mud.