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Emissions at Deepwater Horizon Controlled Burns Were Below Levels of Concern

Evergreen Burner

The U.S. Environmental Protection Agency today released two peer reviewed reports concerning dioxins emitted during the controlledburns of oil during the Deepwater Horizon BP spill. The reports found that while small amounts of dioxins were created by the burns, the levels that workers and residents would have been exposed to were below EPA’s levels of concern. Controlled burning of oil on the surface of the ocean (also called insitu burning) was one method used by the Unified Command during theDeepwater Horizon BP oil spill, to reduce the spread of oil and environmental impacts at the shoreline. A total of 411 controlled burnevents occurred of which 410 could be quantified, resulting in thecombustion of an estimated 222,000 to 313,000 barrels of oil (or 9.3 to13.1 million gallons).

Dioxins are a category that describes a group of hundreds of potentially cancer-causing chemicals that can be formed during combustion orburning.

With support from the U.S. Coast Guard, EPA conducted sampling of emissions at the source of the controlled burns in the Gulf of Mexico to determine if dioxins were present. The sampling was conducted to identify potential dioxin exposures and determine the potential risks from inhalation to workers in the vicinity of the fires, risks from inhalation to the general population and risks to the general population from consuming fish caught in the area.

The first report summarizing EPA’s sampling effort indicates that while dioxins were created from the burning of oil on ocean water, they were created at low levels – levels similar to the emissions from residential woodstoves and forest fires. The second report, coauthored with scientists from the National Oceanic and Atmospheric Administration (NOAA), presents the results of a screening risk assessment for the dioxins emitted from the controlled oil burns. The results indicate that increased cancer risk due to exposure to the dioxins released from the controlled burning of oil was small - less than a 1 in 1,000,000 increased cancer risk. Additional cancer risks for inhalation by workers and onshore residents and fish consumption by residents were lower than risk levels that typically are of concern to the agency.

Typically, the agency has a concern when therisk is greater than 1 in 1,000,000. Had the spill of oil continued, the results of these measurements would have been used by the Unified Command to determine if burning should continue. However, the well was capped on July 15, 2010 and the last insitu burn occurred on July 19, 2010. Consequently, these results aremost useful to inform and improve the agency’s ability to respond tofuture oil spills.

EPA and other federal agencies have developed a broad set of questionsand answers to provide the public with general information on dioxins, including what they are, where they can be found, and major sources of dioxins. The questions and answers explain the review process for thedioxin reassessment and discuss possible effects of dioxin exposure in humans, including advice about consumption of food that might contain dioxins.

Both reports and questions and answers about both reports 

General information on dioxins