On 20th April 2010, a deadly explosion on the Deepwater Horizon drilling rig in the Gulf of Mexico left 11 people dead. As the rig sank, the riser pipe connecting the platform to the oil well ruptured and began spewing vast amounts of crude oil into the sea. The broken pipe lay near the sea bed, 5000ft down. The well's operators, BP, tried and failed to stem the flow of oil. Soon a huge oil slick had developed threatening the ecosystem in the Gulf. After 87 days the well was finally capped. But by then more than 130 million gallons of oil had entered the marine environment. It was one of the worst environmental disasters in US history. Alex Last spoke to Dr Lisa Dipinto a Chief Scientist from the Office of Response and Restoration at NOAA, who worked on the impact of the spill.

Photo: The offshore oil rig Deepwater Horizon burning off the coast of Louisiana 21 April 2010 (U.S. Coast Guard/Reuters)