The dispute underlying the UKSC's decision stems from an explosion, followed by an oil spill, on the Deepwater Horizon offshore drilling rig that began on 20 April 2010 in the Gulf of Mexico (the " Disaster "). Built in 2001, the Deepwater Horizon was a drilling rig situated in the Gulf of Mexico and was owned by the Swiss company Transocean Holdings LLC (" Transocean "). Transocean leased the Deepwater Horizon to BP Exploration and Production Inc. (" BP "), which contracted Halliburton Company (" Halliburton ") to provide certain services.