On 20 April 2010, an explosion occurred on the "Deepwater Horizon" oil rig, operated by BP. Eleven people were killed in the blast and oil began to leak from the ocean floor at a rate variously estimated to be between and per day. Hayward, and BP in general, initially downplayed the spill, stating on 17 May 2010 that the environmental impact of the Gulf spill would likely be "very very modest" and calling the spill "relatively tiny" in comparison with the size of the ocean. By 27 May, Hayward changed his assessment, calling the spill an "environmental catastrophe" in an interview with CNN.