The mammoth oil spill off the Gulf of Mexico is horrifying, to be sure, but the chemical oil dispersants that BP started using just a week after the spill may be hurting more than helping. BP briefly stopped using the chemicals so that the EPA could perform testing. Now the EPA has approved Corexit 9500 and Corexit(R) EC9527A for use in the spill, according to ProPublica. The big problem: Nobody really knows what's inside Corexit.
Trade secrets keep the exact ingredients from being revealed, and safety sheets show that Corexit contains compounds that can cause vomiting, reproductive problems, and headaches at high doses. No toxicity studies have been performed on the compounds, but an environmental group called Protect the Ocean claims that Corexit is four times as toxic as the oil. And an earlier form of Corexit used in the Exxon Valdez cleanup reportedly caused workers to develop nervous system, blood, and respiratory disorders.
They’re also called dispersants for a reason. The chemicals break up the oil and then disperse it, so instead of having the oil collect at the surface, dispersed droplets of oil can spread more quickly and in more directions. This means the droplets linger longer in the water, collecting on the seabed and harming the ecosystem offshore. Using dispersants involves a trade-off, according to a 2005 National Academy of Sciences report. It’s a choice between diluting oil droplets more broadly and invisibly in the ocean and seeing thick gobs of it coating seabirds and beaches.
Dispersants still need to be used, but there are better chemical dispersants out there than Corexit. Wired reports that a dispersant called Dispersit was approved 10 years ago by the EPA for emergency cleanup. Dispersit is twice as effective at breaking down crude oil and half as toxic as Corexit. But Corexit has been the dispersant of choice in past oil spills, and it's what oil companies have in their stockpiles. If field tests with Dispersit go well, we can only hope that BP relents and gives it a chance. Otherwise, we risk bringing all those toxic side effects from Corexit into the human food chain.
UPDATE: In a statement to the Gulf Oil Disaster Recovery Group, toxicology expert Dr. William Sawyer elaborated on the risks associated with Corexit. According to Sawyer, Corexit is also known as deodorized kerosene—a substance with health risks to humans as well as sea turtles, dolphins, breathing reptiles, birds, and any species that need to surface for air exchanges.