On April 20, 2010, at about 10 p.m., an explosion occurred on the Deepwater Horizon oil drilling rig in the Gulf of Mexico. There were 126 people on board at the time. Fifteen of those were injured and eleven died. The Deepwater Horizon, owned by Transocean Ltd., was under contract with BP to drill an exploratory well. BP was the lessee of the area in which the rig was operating. At the time of the explosion, BP and Transocean were in the process of temporarily closing the well, in anticipation of returning it to commercial production. Another company, Halliburton, had completed some cementing of casings in the well less than 24 hours prior to the accident. The Coast Guard responded to the explosion and fire.
The next day, on April 21, 2010, pursuant to the National Contingency Plan, the Administration named Rear Admiral Mary Landry as the Federal On-Scene Coordinator. A regional response team was established, including representatives of the Coast Guard, Department of Homeland Security (DHS), Department of Commerce (DOC)/National Oceanic and Atmospheric Administration (NOAA), Department of the Interior (DOI) and the Environmental Protection Agency (EPA), as well as state and local representatives. The regional response team began developing plans, providing technical advice and access to resources and equipment from its member agencies, and overseeing BP