The U.S. Environmental Protection Agency asked BP Plc to use a less toxic chemical dispersant on the oil spill in the Gulf of Mexico within the week.
The agency sent BP a directive, giving the company 24 hours to select an alternative dispersant for approval and 72 hours to begin using that alternative.
BP, based in London, has been using Nalco Holding Co.’s Corexit, a chemical that has been banned in the U.K., as part of its clean-up plans for a spill that started after the Deepwater Horizon rig exploded April 20 and sank two days later.
BP has been using a squadron of planes to apply dispersants to the spill at the surface, aiming to break the slick into small droplets that will eventually be digested by microbes. The company has also been using robots to apply dispersants on the sea floor, closer to the source of the leaking Macondo well, a practice never used before.
“Because of its use in unprecedented volumes and because much is unknown about the underwater use of dispersants, EPA wants to ensure BP is using the least toxic product authorized for use,” the agency said in a statement.
There are at least five chemical dispersants available that are more effective than Corexit and are less toxic in mysidopsis shrimp, according to evidence presented at the House Transportation Committee hearing yesterday.
“We are reviewing four alternative dispersants, using information in the public domain,” Mark Salt, a BP spokesman, said today in a telephone interview from Houston.
The company and responders have used dispersants as conditions permit. Yesterday they were used both on the surface and about one mile below it, said U.S. Coast Guard Petty Officer Erik Swanson at the Joint Information Center in Robert, Louisiana.
“Toxicity data does not indicate any significant affects on aquatic life. Moreover, decreased size of the oil droplets is a good indication that, so far, the dispersant is effective,” Naperville, Illinois-based Nalco said in a statement.
The EPA’s request was reported earlier today by the Washington Post.