The "Deepwater Horizon" oil spill is also called the BP oil spill, the Gulf of Mexico oil spill, or the Macondo blowout. It was an oil spill in the' Gulf of Mexico, the largest marine oil spill in history. The spill was caused by an oil gusher when the drilling machines exploded on April 20, 2010. The explosion killed 11 workers and injured 17 people.