ROBERT, La. – A massive oil leak in the Gulf of Mexico has become the testing ground for a new technique where a potent mix of chemicals is shot deep undersea in an effort to stop oil from reaching the surface, and scientists are hurriedly weighing the ecological risks and benefits.
Crews battling the spill already have dropped more than 156,000 gallons of the concoction — a mix of chemicals collectively known as "dispersant" — to try to break up the oozing oil, allowing it to decompose more quickly or evaporate before washing ashore.
The technique has undergone two tests in recent days that the U.S. Coast Guard is calling promising, and there are plans to apply even more of the chemicals. But the effect of this largely untested treatment is still being studied by numerous federal agencies, and needs approval from a number of them before it can be rolled out in a larger way.
"Those analyses are going on, but right now there's no consensus," said Charlie Henry, the scientific support coordinator for the National Oceanic and Atmospheric Administration. "And we're just really getting started. You can imagine it's something we've never thought about."
Chemical dispersants carry complex environmental trade-offs: helping to keep oil from reaching sensitive wetlands while exposing other sea life to toxic substances. The concoction works like dish soap to separate oil and water, but the exact chemical composition is protected as a trade secret.
More than 230,000 gallons of dispersant is available, and more is being manufactured by Nalco Company of Naperville, Ill., for use in the Gulf. Neither Nalco, BP, rig owner Transocean Ltd or the Coast Guard have specified how much of the chemical brew will be needed to handle this spill.
One of the chief agents being used, called Corexit 9500, is identified as a "moderate" human health hazard that can cause eye, skin or respiratory irritation with prolonged exposure, according to safety data documents.
According to the company, Corexit contains no known carcinogens or substances on the federal government's list of toxic chemicals.
Even some of the most ardent environmentalists, while concerned about the potential effects, aren't suggesting that the chemical concoction shouldn't be used in this case.
"It's basically a giant experiment," said Richard Charter, a senior policy adviser with Defenders of Wildlife. "I'm not saying we shouldn't do it; we have no good options."
A dead sea turtle has been found on the shore in Dauphin Island. George Crozier, director of the Dauphin Island Sea Lab, said Tuesday that scientists don't think the death is linked to the oil spill in the Gulf of Mexico. Necropsies on 29 turtles found along Mississippi beaches over the weekend revealed no evidence of oil. Experts warn the turtles may have eaten fish contaminated by the oil spill. Results from tissue samples taken at a marine life rehabilitation center in Gulfport, Miss. are to return in a week.