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OSRR-1016-Comparative Testing of Corexit EC9500A, Finasol OSR 52, Accell Clean DWD, and ZI 400 at Ohmsett in a Simulated Arctic Environment

Project Initiation Date
Performing Activity
Bureau of Safety and Environmental Enforcement (BSEE)
Principal Investigator
Timothy Steffek
Estimated Completion Date

The Bureau of Safety and Environmental Enforcement (BSEE) recently conducted independent dispersant effectiveness testing. Four dispersants were selected from the Environmental Protection Agency's (EPA) National Contingency Plan (NCP) Product Schedule and were tested on an Alaskan crude oil under simulated arctic conditions at Ohmsett. They include Corexit® EC9500A, Finasol® OSR 52, Accell® Clean DWD, and ZI 400. To capture operational effectiveness issues, the dispersants were applied to a surface slick using Ohmsett's spray bar, which simulated a system similar to a boat spraying system. Data collected included dispersant effectiveness (DE) based on the volume of the surface slick which remained after the test as compared to the volume dispersed into the water column and droplet size distribution. In addition to providing performance data of the products in pseudo-field conditions, operational performance was captured as a general discussion about the ease of use, limitations, and concerns about the products in the arctic environment.

Latest progress update

This project has been completed.The performance of the products was quantified and compared to each other based on DE and the droplet size of dispersed oil. Corexit EC9500A performed very well in this study as compared to the other dispersants, producing the highest average DE, the most improvement in dispersion compared to the tests with untreated oil, and the smallest median droplet size. Finasol OSR 52 demonstrated a performance close to that of Corexit, producing the second highest average DE, and a median droplet size only slightly larger than Corexit. The average DE for Accell fell between that of Finasol and ZI 400, as did the median droplet size. ZI 400 performed poorly relative to the other products tested. Addionally, ZI 400 was the only product observed to be negatively impacted by the cold weather environment.

The final report is currently being peer reviewed and will be available shortly.