After several members of cleanup crews aboard fishing vessels off the coast of Louisiana fell ill in late May 2010, fears about the health consequences of the dispersants in the gulf spiked. The National Institutes of Health is currently conducting a study of the more than 54,000 members of response crews deployed to the Gulf to determine whether their health suffered from exposure to crude oil and dispersants.
Some scientists also worry that the dangers will increase exponentially when the gulf is hit with its next major tropical storm, which could release massive amounts of oil and dispersant chemicals currently covered by sediment.
Nalco denied that its product has contributed to any human health problems on the gulf and believes the lawsuits against it lack merit, spokesman Roman Blahoski said, adding that the company had no part in decisions affecting where and how Corexit was used following the spill.
Corexit 9527, used more heavily in the beginning of the response, contains 2-butoxyethanol, a chemical believed to have caused health problems following the 1989 Exxon Valdez spill. The EPA, which considers it a chronic and acute health hazard, asked BP to find a less toxic alternative to Corexit, but BP agreed only to reduce the volume it was spraying.
Despite Nalco's effort to keep the ingredients a trade secret, the EPA released them after it was prompted to do so by Sen. Kirsten Gillibrand (D-NY) under the Toxic Substances Control Act.
It may be years before scientists understand how the dispersants used in the spill response will affect the marine environment and the food chain, in part because of the difficulty of studying dispersants at extreme depths. According to Ralph Portier, a professor of environmental science at Louisiana State University, the pressure levels at the sea floor renders methodologies used so far to study dispersants inapplicable.
"This is a case where the science hasn't kept up with the engineering, the deep ocean exploration and oil fuel production," he said. "The GAO report is correct. There's a whole block of data missing."
Another challenge to scientists, Portier said, is distinguishing the effects of the dispersant chemicals from those of the oil and those of the oil-dispersant mixtures.
Scientists will not be able to judge the recovery of the gulf ecosystem until the spill reaches its third anniversary, Portier said, but the consensus among scientists appears to be a "quiet hope."
At least as far as seafood is concerned, that hope appears to be warranted. So far, the seafood testing program coordinated by state and federal governments and BP has succeeded in preventing contaminated seafood from going on the market, said Kyle Graham, a spokesman for the Louisiana Coastal Protection and Restoration Authority.
Still, according to Cowan, some researchers believe the public has been misled about the true damage still unfolding in the gulf by states eager to protect domestic industries. Because the seafood crucial to the Gulf Coast economy has been deemed safe, the pollution's net impact on the aquatic ecosystem has had a lower profile in the press.
"The states are doing what they need to do, and I understand where they're coming from, but there is a potential for long-term toxicological effects in the gulf," Cowan said. "We are going to be dealing with this for quite a while."