Determining the dispersibility of South Louisiana crude oil by eight oil dispersant products listed on the NCP Product Schedule

► We measured the dispersion effectiveness of eight dispersants at 5 and 25°C. ► The Baffled Flask Test was used as the main testing method. ► Results are useful to determine utility of dispersant use in the Gulf of Mexico. ► Only three of the eight dispersants gave acceptable dispersion effectiveness results. ► Temperature was not as critical as the literature suggested. We recently conducted a laboratory study to measure the dispersion effectiveness of eight dispersants currently listed on the National Contingency Plan Product Schedule. Results are useful in determining how many commercial dispersant products would have been effective for use on South Louisiana crude oil in the Deepwater Horizon oil spill. The test used was a modification of the Baffled Flask Test (BFT), which is being proposed to replace the current Swirling Flask Test (SFT). The modifications of the BFT in this study included use of one oil rather than two, increasing replication from 4 runs to 6, and testing at two temperatures, 5°C and 25°C. Results indicated that temperature was not as critical a variable as the literature suggested, likely because of the low viscosity and light weight of the SLC. Of the eight dispersants tested, only three gave satisfactory results in the laboratory flasks at both temperatures.