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 in August 2010. USF's David Hollander remarked, "Oil's presence on the ocean floor didn't diminish with time; it grew" and he pointed out, "the layer is distributed very widely," radiating far from the wellhead. In 2013, some scientists at the "Gulf of Mexico Oil Spill and Ecosystem Science Conference" said that as much as one-third of the oil may have been mixed with deep ocean sediments and dragged to the bottom of the ocean floor where it remains, risking damage to ecosystems and commercial fisheries. Oil at or near the site of the spill following well closure has suggested to