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
Economic effects of the Deepwater Horizon oil spill the total liability could amount to as much as by the conclusion of the disaster. Financial analysts commented that BP was capable of addressing the potential liabilities that might result, and BP stock rose slightly on the news that the initial compensation fund had been agreed. On 5 July 2010, BP reported that its own expenditures on the oil spill had reached $3.12 billion, including the cost of the spill response, containment, relief well drilling, grants to the Gulf states, claims paid, and federal costs. As of 1 October 2010, BP has spent $11.2 billion. As of March 2012, BP