The oil spill response industry is changing products used to disperse spilled oil. This change stemmed from new protocols put in place by the U.S. Environmental Protection Agency, or EPA, for testing dispersants.
The EPA maintains a list of products that have gone through a testing process and met the established thresholds for listing.
The manufacturer of Corexit 9500A, the product that made up the stockpile in Alaska and elsewhere, recently discontinued manufacturer, sale, and regulatory support. Corexit 9500A will no longer be included on the EPA list after December 12, 2025.
The stockpile of dispersants in Alaska is maintained by the Marine Spill Response Corporation, or MSRC, a nationwide company that supports oil spill response incidents. They own and maintain stockpiles of equipment and trained response personnel that can be deployed across the U.S. Their warehouse in Anchorage is now home to about 60,000 gallons of a new product, Dasic EcoSafe OSD.
Makeup of new dispersant is unclear
According to its Safety Data Sheet, or SDS, Dasic EcoSafe contains four surfactants and two solvents.
Surfactants are substances that reduce the surface tension of a liquid, allowing it to spread more easily. For example, shampoo contains surfactants that remove oil from hair.
Solvents are substances, usually liquid, that can dissolve another substance. For example, water acts as a solvent in the digestive system, dissolving nutrients from food and delivering it into the bloodstream.
The SDS lists the same surfactants and solvents in Dasic EcoSafe as Corexit, however the amounts and ratios cannot be determined from public data.
There is not much publicly available data about the new dispersant other than the SDS. In addition, testing methods to determine toxicity have changed in recent years so comparisons to previous products is difficult.
The tests conducted to gain the EPA’s approval were done on oil from locations in the Lower 48. Crude oil varies according to where it came out of the earth. Properties such as viscosity (whether a liquid is thick and flows slowly, or thin and faster flowing) or density (how compact the substance is) affect how the oil reacts with dispersants. Crude oil in the Lower 48 tends to be lighter and faster flowing than North Slope oil.
Plan for Corexit stockpile yet to be determined
The MSRC is considering several options for disposal of the existing Anchorage stockpile and expects to have a plan sometime in 2026.