SAN FRANCISCO - The Center for Biological Diversity today filed an official notice of its intent to sue the Environmental Protection Agency for authorizing the use of toxic dispersants without ensuring that these chemicals would not harm endangered species and their habitats. The letter requests that the agency, along with the U.S. Coast Guard, immediately study the effects of dispersants on species such as sea turtles, sperm whales, piping plovers, and corals and incorporate this knowledge into oil-spill response efforts.

An Air Force plane drops an oil-dispersing chemical into the Gulf of Mexico as part of the Deepwater Horizon Response effort. In theory, chemical dispersants allow the oil to be eaten by microorganisms and become diluted faster than it would otherwise. However, the effects of using large quantities of highly toxic dispersants and injecting them into very deep water, as BP has done in the Gulf of Mexico, have never been studied. (Photo: Technical Sergeant Adrian Cadiz) "The Gulf of Mexico has become Frankenstein's laboratory for BP's enormous, uncontrolled experiment in flooding the ocean with toxic chemicals," said Andrea Treece, an attorney with the Center for Biological Diversity. "The fact that no one in the federal government ever required that these chemicals be proven safe for this sort of use before they were set loose on the environment is inexcusable."

Dispersants are chemicals used to break oil spills into tiny droplets. In theory, this allows the oil to be eaten by microorganisms and become diluted faster than it would otherwise. However, the effects of using large quantities of dispersants and injecting them into very deep water, as BP has done in the Gulf of Mexico, have never been studied. Researchers suspect that underwater oil plumes, measuring as much as 20 miles long and extending dozens of miles from the leaking rig, are the result of dispersants keeping the oil below the surface.

On May 24, EPA Administrator Jackson expressed concern over the environmental unknowns of dispersants, which include the long-term effects on aquatic life. Nonetheless, the federal government has allowed BP to pump nearly 1 million gallons of dispersants into the Gulf of Mexico.

"Pouring dispersants into vital fish nursery grounds and endangered species habitat simply trades one evil for another. Had the government first examined dispersants before the disaster, we would not be left wondering what sort of havoc BP is wreaking on the ecosystem just so it can make the oil less visible," added Treece. "We cannot and will not allow this to happen again."

Studies have found that oil dispersed by Corexit 9527 damages the insulating properties of seabird feathers more than untreated oil, making the birds more susceptible to hypothermia and death. Studies have also found that dispersed oil is toxic to fish eggs, larvae, and adults, as well as to corals, and can harm sea turtles' ability to breathe and digest food. Formulations of the dispersants being used by BP, Corexit 9500 and 9527, have been banned in the United Kingdom due to concerns over their impacts on the marine environment.