Screening Level Assessment of Risks Due to Dioxin Emissions from Burning Oil from the BP Deepwater Horizon Gulf of Mexico Spill

This report from the Environmental Protection Agency finds that between April 28 and July 19 of 2010, the US Coast Guard conducted in situ oil burns as one approach used for the management of oil spilled after the explosion and subsequent sinking of the BP Deepwater Horizon platform in the Gulf of Mexico.

The purpose of this paper is to describe a screening level assessment of the exposures and risks posed by the dioxin emissions from these fires. Using upper estimates for the oil burn emission factor, modeled air and fish concentrations, and conservative exposure assumptions, the potential cancer risk was estimated for three scenarios: inhalation exposure to workers, inhalation exposure to residents on the mainland, and fish ingestion exposures to residents. U.S. EPA’s AERMOD model was used to estimate air concentrations in the immediate vicinity of the oil burns and NOAA’s HYSPLIT model was used to estimate more distant air concentrations and deposition rates. The lifetime incremental cancer risks were estimated as 6 x 10-8 for inhalation by workers, 6 x 10-12 for inhalation by onshore residents and 6 x 10-8 for fish consumption by residents.

For all scenarios, the risk estimates represent upper bounds and actual risks would be expected to be less.

Aerostat Sampling of PCDD/PCDF Emissions from the Gulf Oil Spill In Situ Burns

This report from the U.S. Environmental Protection Agency, Office of Research and Development, National Risk Management Research Laboratory, finds that a 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.