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
Oil reserves in Mexico these problems, in September 2007, Mexico’s Congress approved reforms including a reduction in the taxes levied on Pemex. Most of Mexico's production decline involves one enormous oil field in the Gulf of Mexico. From 1979 to 2007, Mexico produced most of its oil from the supergiant Cantarell Field, which used to be the second-biggest oil field in the world by production. Because of falling production, in 1997 Pemex started a massive nitrogen injection project to maintain oil flow, which now consumes half the nitrogen produced in the world. As a result of nitrogen injection, production at Cantarell rose from in