Impact of Gulf Spill’s Underwater Dispersants Examined

Published on
by
The New York Times

Impact of Gulf Spill’s Underwater Dispersants Examined

by
Joanna Foster

A Basler BT-67 aircraft releasing dispersant off the shore of Louisiana in May 2010. (Stephen Lehmann/Coast Guard, via European Pressphoto Agency)

In the wake of the Deepwater Horizon oil spill, BP sought and obtained permission to use dispersants, detergent-like compounds, to break up the 200 million gallons of Louisiana sweet crude, into tiny droplets that would mix throughout the water column, trying to lessen the immediate impact of the oil slick on fragile coastal ecosystems.

The dispersants selected, Corexit 9500 and Corexit 9527, were used in large quantities (1.84 million gallons) and also in ways never before used — they were applied directly underwater to the source of the spill. One month after oil first started gushing into the Gulf of Mexico, the federal Environmental Protection Agency gave BP 24 hours to identify, and 72 hours to begin using, a less toxic alternative.

There were, at the time, 14 dispersants listed on the National Contingency Plan Product Schedule — a list of emergency-use products maintained by the E.P.A. for combating oil spills. BP, however, continued using Corexit, citing a vast paucity of data concerning the environmental impacts of any of the alternative dispersants.

As the situation in the Gulf worsened and questions about the safety of Corexit spread like, well, leaking oil, Earthjustice, a nonprofit environmental law firm, filed a Freedom of Information Act request to obtain information about the composition and safety of the dispersants listed as eligible for use. When the federal agency did not comply, Earthjustice sued on behalf of the Gulf Restoration Network and the Florida Wildlife Federation.

In response, the E.P.A. published the full chemical composition of Coexit 9500 and Corexit 9527 and nearly a year later, released an aggregate list of 57 chemical components found in the 14 dispersants, although they provided no information about which chemicals were found in which dispersants, citing an obligation to protect what had been deemed as confidential business information by the manufacturers.

A review has now been published by Earthjustice, in collaboration with Toxipedia, an online toxicology Wiki, of all the scientific literature concerning the potential health impacts of these 57 chemicals. The report finds that “Of the 57 ingredients: 5 chemicals are associated with cancer; 33 are associated with skin irritation from rashes to burns; 33 are linked to eye irritation; 11 are or are suspected of being potential respiratory toxins or irritants; 10 are suspected kidney toxins; 8 are suspected or known to be toxic to aquatic organisms; and 5 are suspected to have a moderate acute toxicity to fish.”

While words like “associated with” or “linked to” may sound weak and unconvincing, the syntax highlights just how little is actually known about these chemicals. For 13 of the dispersant ingredients, no relevant data could be found.

“BP had a particular set of dispersants on hand and no one at the time seemed to know if they were safe, whether they were safer than other dispersants products that could be used or even whether they were safer for people and the environment than oil alone,” said Marianne Engelman Lado, a lawyer with Earthjustice. “BP chose Corexit because it was the dispersant on hand, not because it was the safest. However, regulation of dispersants is so inadequate that BP didn’t have enough information to figure out how it compared with other dispersants or oil alone.”

Nick Thorp, a project manager at Toxipedia, said:

There is just not a lot known about these chemicals and their linkages to potential health impacts. More research is really necessary to determine what exposure levels are, and aren’t safe. Ideally these questions would have been answered before the dispersants were approved for use. We’re now backtracking trying to answer these questions, after the public and the environment have already been exposed.

Earthjustice is calling for “more research, greater disclosure of the information that is known, comprehensive toxicity testing, establishment of safety criteria for dispersants, and careful selection of the least toxic dispersants for application in oil spill response.”

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