High Quality Content by WIKIPEDIA articles! The Deepwater Horizon drilling rig explosion refers to the April 20, 2010 explosion and subsequent fire on the Deepwater Horizon semi-submersible Mobile Offshore Drilling Unit (MODU), which was owned and operated by Transocean and drilling for BP in the Macondo Prospect oil field about 40 miles (60 km) southeast of the Louisiana coast. The explosion killed 11 workers and injured 16 others. The explosion caused the Deepwater Horizon to burn and sink, resulting in a massive offshore oil spill in the Gulf of Mexico, considered the largest accidental marine oil spill in the world, and the second largest environmental disaster in U.S. history, behind the Dust Bowl.