Health consequences of the Deepwater Horizon oil spill effects, while even very low doses can cause mutagenic effects, with cancer of particular concern. The carcinogens of concern in crude oil are benzene and polycyclic aromatic hydrocarbons (PAHs), which are present in oil and in the air as a result of offshore controlled burning of crude oil. During the 2010 BP/Deepwater Horizon Gulf oil spill, an estimated one of every 20 barrels of spilled oil was deliberately burned off. Routes of exposure include contact and inhalation. The EPA obtained hundreds of air samples during the spill and a review showed that none of the samples showed concentrations of benzene
Volume and extent of the Deepwater Horizon oil spill collected before it could enter the Gulf waters. In its permit to drill the well, BP estimated the worst-case flow at . Immediately after the explosion the USCG did not estimate any oil leaking from the sunken rig or from the well. On 24 April, USCG Rear Admiral Mary Landry announced that a damaged wellhead was indeed leaking. She stated that "the leak was a new discovery but could have begun when the offshore platform sank . . . two days after the initial explosion." Initial estimates by USCG and BP officials, based on remotely operated vehicles as well as