August 3, 2010

EPA: Corexit 9500A Dispersant No Worse Than Others

A new study showed on Monday that dispersants mixed with crude are no more toxic to marine life than oil alone and the type used by BP in the Gulf of Mexico is no worse than any others.

The US Environmental Protection Agency (EPA) ordered toxicity tests on eight types of dispersants, including Corexit 9500A, which was used widely by BP to break up the oil slick in the Gulf.

An earlier study on the toxicity levels concluded, as BP had always maintained, that Corexit was no more toxic than other dispersants, while the latest study showed the same evidence when it was mixed with the crude.

"The results indicate that the dispersant-oil mixtures are generally no more toxic to test species than oil alone," Paul Anastas, EPA's assistant administrator for research, told AFP.

"The eight dispersants tested have similar toxicities to one another when mixed with Louisiana sweet crude oil. They would generally be categorized in the moderate range," he added.

The tests conducted by the EPA were used with aquatic species that are characteristic of marine life found in the Gulf of Mexico. They were carried out during a juvenile life stage when organisms are more sensitive and "over a range of concentrations including those much greater than what aquatic life is expected to encounter in the Gulf," Anastas said.

BP stopped using chemical dispersants in the Gulf on July 19, and the EPA said it had not detected any dispersant away from the actual wellhead near Louisiana's fragile coastal wetlands.

EPA rules prohibit the application of dispersants near wetlands or within three miles of the coast.


Image Caption: A U.S. Air Force chemical dispersing C-130 aircraft from the 910th Airlift Wing at Youngstown-Warren Air Reserve Station, Ohio, drops an oil dispersing chemical into the Gulf of Mexico as part of the Deepwater Horizon Response effort, May 5, 2010. U.S. Air Force Photo by Tech. Sgt. Adrian Cadiz.


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