The Deepwater Horizon oil spill is considered one of the largest marine oil spills in the history of the United States. Air emissions associated with the oil spill caused concern among residents of Southeast Louisiana. The purpose of this study was to assess ambient concentrations of benzene (n=3,887) and fine particulate matter (n=102,682) during the oil spill and to evaluate potential exposure disparities in the region. Benzene and fine particulate matter (PM2.5) concentrations in the targeted parishes were generally higher following the oil spill, as expected. Benzene concentrations reached 2 to 19 times higher than background, and daily exceedances of PM2.5 were 10 to 45 times higher than background. Both benzene and PM2.5 concentrations were considered high enough to exceed public health criteria, with measurable exposure disparities in the coastal areas closer to the spill and clean-up activities. These findings raise questions about public disclosure of environmental health risks associated with the oil spill. The findings also provide a science-based rationale for establishing health-based action levels in future disasters. Implications: Benzene and particulate matter monitoring during the Deepwater Horizon oil spill revealed that ambient air quality was a likely threat to public health and that residents in coastal Louisiana experienced significantly greater exposures than urban residents. Threshold air pollution levels established for the oil spill apparently were not used as a basis for informing the public about these potential health impacts. Also, despite carrying out the most comprehensive air monitoring ever conducted in the region, none of the agencies involved provided integrated analysis of the data or conclusive statements about public health risk. Better information about real-time risk is needed in future environmental disasters.

The paper describes, in historical and international perspective, the ongoing struggles of several communities in Louisiana and South Africa whose environment and public health have been damaged by the operations of the same transnational corporations. Previous research has tended to assess environmental injustice one community at a time. Missing from past research is an international perspective which exposes the ties between communities that host the same transnational corporations. For each of our case study communities, we illustrate the national and international policy gaps that have allowed powerful companies to systematically target vulnerable communities for profit. Because of the international dimensions of this problem, resolving it by local or national action alone is impractical. We argue that one of our case study communities represented a turning point in the international movement for environmental justice. The community of Mossville, Louisiana formally asked the United Nations for relief from years of environmental assault on the basis that their human rights had been violated. The paper shows how the decision of the Inter-American Commission on Human Rights, which recognized the human rights of Mossville residents, came closer than ever before to realizing environmental human rights for people around the world.