Estimation of Aerosol Concentrations of Oil Dispersants COREXIT™ EC9527A and EC9500A during the Deepwater Horizon Oil Spill Response and Clean-up Operations

Susan Arnold, Patricia A. Stewart, Gregory C. Pratt, Gurumurthy Ramachandran, Richard K. Kwok, Lawrence S. Engel, Dale P. Sandler, Mark R. Stenzel

Research output: Contribution to journalArticlepeer-review

13 Scopus citations


The April 2010 Deepwater Horizon drilling unit explosion at the Macondo oil well resulted in the release of approximately 779 million l of oil into the Gulf of Mexico. As part of the response effort to break up oil slicks on the water's surface, 6.81 million l of chemical dispersants COREXIT™ EC9500A and COREXIT™ EC9527A were applied by plane or vessel or injected near the seabed. The GuLF Long-term Follow-up Study is investigating possible adverse health effects of workers involved in the oil spill response and clean-up (OSRC). In this paper, we describe potential dispersant-related air concentrations generated from aerial spraying of dispersants to provide insight as to what concentrations OSRC workers may have been exposed under worst-case conditions. Personal exposure measurement data were not collected. Modeling, therefore, was conducted to estimate airborne concentrations of total aerosol to COREXIT™ EC9527A and EC9500A. Using the AgDISP model, we estimated air concentrations to dispersant total aerosols, defined as all components of the dispersant including active ingredients, surfactants, and water, resulting from aerial and vessel applications, as average 1-h and 2-min concentrations. For comparison, 1-h air concentrations associated with aerial spraying were estimated using another model, AERMOD. At 152 m horizontal to the flight path, average 1-h total aerosol concentrations associated with aerial applications were estimated to be as high as 49.3 μg m-3 (9527A) and 45.4 μg m-3 (9500A), and both decreased with increased distance from the flight line. The estimates for spraying 9500A from vessels indicated that total aerosol concentrations were potentially as high as 0.33 μg m-3 at 10 m from the nozzles. These results suggest that personal exposures to dispersant aerosols were negligible.

Original languageEnglish (US)
Pages (from-to)I188-I202
JournalAnnals of Work Exposures and Health
Issue numberSuppl 1
StatePublished - Apr 1 2022

Bibliographical note

Funding Information:
This study was supported by the National Institutes of Health Common Fund and the Intramural Research Program of the National Institutes of Health, National Institute of Environmental Health Sciences (ZO1 ES 102945)

Publisher Copyright:
© 2022 The Author(s) 2022. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.


  • Deepwater Horizon Oil Spill
  • aerosol
  • chemical dispersant
  • exposure assessment
  • Water
  • Water Pollutants, Chemical/analysis
  • Follow-Up Studies
  • Humans
  • Occupational Exposure/adverse effects
  • Aerosols
  • Petroleum Pollution/analysis

PubMed: MeSH publication types

  • Research Support, N.I.H., Intramural
  • Journal Article
  • Research Support, N.I.H., Extramural


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