Evaporating oil from BP spill likely posed a health threat, study says

By Mark Schleifstein, The Times-Picayune
March 10, 2011 A new study about the way oil from the BP Deepwater Horizon accident evaporated into the air confirms that cleanup workers were exposed to high levels of airborne pollution, and that the fumes also may have made their way onshore in Louisiana. The study does not attempt to assess the resulting health and environmental effects. The study’s authors also found that the way fumes from the oil combined with particles already in the air could provide a major clue to the way harmful air pollution forms from vehicle and other exhausts in urban areas. Last June, scientists took air samples during flights over the vast area where oil was on the surface of the Gulf of Mexico. The researchers found that 30 percent of the oil that made its way to the surface was made up of “light volatile organic carbon molecules” that evaporated within 10 hours. Another 10 to 20 percent of the surface oil was made up of heavier compounds that took several days to evaporate. The lighter compounds combined with particles in the air and were found in a narrow plume stretching from the Macondo well northwest towards the mouth of the Mississippi River. A much wider plume of aerosols associated with the heavier compounds was found stretching across the northern edge of the oil, also moving northwest with prevailing winds towards the Louisiana coastline. While the report does not directly address the environmental and human health effects of the aerosols, the results do indicate that offshore clean-up workers were exposed to both the vapors and the aerosol compounds, and that prevailing winds may have carried the aerosols onshore, said Joost de Gouw, lead author of the peer-reviewed report in the March 11 edition of Science magazine. “These concentrations were high,” de Gouw said. “They are much higher than what you and I are exposed to in cities. We need to have a closer look at how these plumes of aerosol impacted people on shore.” …