Oil spill dispersal. Basler BT-67 fixed wing aircraft releasing oil dispersant over an oil discharge from the sunken mobile offshore drilling unit, Deepwater Horizon. The spill followed a blowout that caused an explosion on the Deepwater Horizon rig, which then sank off the coast of Louisiana. The oil spill, originating from the blowout 1,500 metres below sea level, is releasing 100s of barrels of oil into the sea each day. Photographed off the shore of Louisiana, USA, on 5th May 2010.