The response to the Deepwater Horizon (DWH) spill was the first large scale use of subsea dispersant injection (SSDI).  Our colleagues at RPS conducted a excellent series of retrospective modeling for the spill to evaluate different SSDI usage scenarios. Dr. Bock collaborated with the RPS team on applying our previously published CRA approach to different model runs, including more optimal SSDI usage scenarios. The paper explores the questions: What if we had used SSDI differently? Can we respond to this type of accident better knowing what we know now? The CRA approach involves using comparative risk assessment to compare the relative risks the various ecological components under various response scenarios. A comparison of mass balance results, exposure metrics, and CRA scoring for Valued Ecological Components (VECs) shows the value of SSDI in achieving overall risk reduction and the tradeoffs that were made across the different VECs. The paper reports that the actual SSDI applied during the DWH oil spill reduced exposures to varying degrees for different VECs. However, exposures and relative risks across the ecosystem would have been substantially reduced with more effective SSDI usage.

https://www.sciencedirect.com/science/article/pii/S0025326X2200460X

TIG Environmental is pleased to host an interactive version of the CRA analysis in this paper that allows you to explore the results for yourself.

https://intell-group.shinyapps.io/DWH-Counter-Historical-Tool/