On 20 April 2010 the crew of the Deepwater Horizon drilling rig, stationed in the Gulf of Mexico for exploratory drilling on the Macondo Well, was carrying out test procedures. During these tests, control of the well was lost which resulted in a large flow of well fluids up the riser. The fluids were diverted to a mud/gas separator which vents above the main deck. This in turn led to a large release of hydrocarbons onto the main deck which quickly engulfed the rig in a hydrocarbon gas cloud. At approximately 9:49 pm ignition of the gas cloud occurred, resulting in several explosions, and a fire ensued on the rig which eventually led to the deaths of eleven workers and at least a dozen serious injuries. It is estimated that nearly five million barrels of hydrocarbons were released into the gulf over a period of nearly three months after the blowout. The disaster is considered the largest accidental marine oil spill in the history of the petroleum industry.