GuLF Study Environmental Health Sciences (NIEHS), part of the National Institutes of Health, and aims to recruit 55,000 of the 150,000 workers who volunteered or were employed to help clean up the spill. It is led by Dale Sandler, head of the NIEHS's epidemiology branch. The "Deepwater Horizon" oil spill was the world's largest accidental marine oil spill. It began on 20 April 2010 after an explosion on the "Deepwater Horizon", a drilling rig leased by BP to drill an exploratory well. Between then and 15 July, when the well was capped, over four million barrels of oil (around 170 million US
Volume and extent of the Deepwater Horizon oil spill of the spill. "With billions of dollars at stake, it is no surprise that they are now litigating the very numbers which they sought to impede." A BP spokesperson said that BP "fully intends to present its own estimate as soon as the information is available to get the science right." The oil's spread was initially increased by strong southerly winds caused by an impending cold front. By 25 April 2010, the spill covered and was only from the ecologically sensitive Chandeleur Islands. An 30 April 2010 estimate placed the total spread of the oil at . The spill quickly