Jackson Free Press

Mississippi Sierra Club Director Louie Miller says the Sierra Club wants to know the environmental consequences of mixing dispersants with the oil jetting out of the devastated Deepwater Horizon oil well off the coast of Louisiana. He joins a growing number of Louisiana state agencies demanding answers about the chemical's safety.

"Our big concern is we're not interested in being BP's guinea pig on dispersants," Miller told the Jackson Free Press this morning. "We've asked for what the chemical composition of these dispersants is, but they're hiding behind proprietary information."

Moby Solangi, director of the Institute for Marine Mammal Studies in Gulfport, said toxicologist can make more effective determinations of the cause of death of marine life washing up on beaches if they have a better understanding of the proprietary chemical BP is using to disperse the oil.

A U.S. Environmental Protection Agency study of Corexit 9527A, the dispersant BP is using to break up oil as it pours from the broken well-head, reveals the chemicals' toxicity multiplies when mixed with oil. The lethal amount of Corexit by itself on menidia beryllina and mysidopsis--a small minnow and a small shrimp that comprise an essential bottom link of the Gulf food chain--is at 14.57 parts per million and 24.14 parts per million respectively. The lethal amount of a mixture of Corexit and low viscosity, however, is at a much lower rate of 4.49 parts per million and 6.60 parts per million. The lower number means a significantly smaller dose of the compound can deliver a deadly reaction. The mixture even extends beyond that of the oil itself, which only has a lethal amount of 10.72 parts per million on the minnow and 16.12 parts per million for the shrimp.

"We know that the chemical by itself is less toxic than the oil, but when that chemical is dispersed into the oil it becomes exponentially more toxic, and that's our big concern," Miller said. "We're getting 400,000 gallons of dispersant on the surface and another 250,000 gallons of dispersant at the well-head, so we need to know the long-term and short-term effects of this stuff."

The Sierra Club is not the only group with concerns. The Louisiana Department of Health and Hospitals, the Louisiana Department of Environmental Quality and the Louisiana Department of Wildlife Fisheries sent a May 8 letter to British Petroleum demanding more information on the toxicity of the dispersant when mixed with oil.

"Three days ago (May 5), in a Unified Command Group meeting that included a BP representative, Louisiana Department of Wildlife Fisheries Secretary Robert Barham requested studies to support usage of the dispersants. As of now (May 8), the state has not received the requested information," the letter stated. "We are again requesting data, analysis and studies of the effects of oil spill dispersants used, and most importantly, a BP commitment that the dispersants being used to fight the oil spill will not cause irreparable, short-term or long-term harm to our wetlands, coast, environment, marine life, wildlife or people."

BP representatives did not immediately return calls.