Studies indicate BP's dispersants made Gulf oil spill and toxicity worse, not better

If BP’s Deepwater Horizon oil spill wasn’t enough of an environmental disaster, two new independent scientific studies indicate that the company’s use of chemical oil dispersants to break down the oil may have done more ecological damage than the oil alone.

Days after BP’s oil spill erupted from its blown-out Macondo well off the Louisiana coastline, the company started spraying the surface of the slick with Corexit, a highly toxic chemical that breaks globs of oil into tiny particles that, theoretically, can be more easily consumed, digested, and expelled by microorganisms in the water. BP also dumped enormous quantities of Corexit under water closer to the source even when subsea applications of the chemical had never been approved or even tested.

The U.S. Environmental Protection Agency initially approved BP’s use of dispersants, but demanded the oil giant stop its use of Corexit and find a less toxic alternative when it realized unprecedented quantities of the chemicals were being used, and in untested applications. BP, however, sent the EPA a letter saying that it couldn’t find replacement dispersants and continued to dump Corexit in the Gulf.

Testing by two separate university researchers now validates the warnings scientists sounded in May 2010 when BP dumped 2 million gallons of Corexit into its 200-million-gallon oil spill.

Wade Jeffrey, a biologist at the University of West Florida’s Center for Environmental Diagnostics and Bioremediation, ran studies in which he added Corexit to seawater mixed with BP oil. But instead of facilitating the degradation of the oil, the Corexit did not prompt the water’s natural microorganisms to consume the oil any faster. Worse, Jeffrey discovered that the seawater laced with Corexit and oil was much more toxic to phytoplankton than water contaminated with oil alone.

Susan Laramore of Florida Atlantic University’s Harbor Branch Oceanographic Institute, studied how water contaminated with oil and Corexit affected larger marine species such as conch, oysters, and shrimp. Laramore also found that the water containing oil and Corexit was worse than water containing oil alone.

“These results are backwards of what the oil companies are reporting,” Laramore told Thinkprogress.

Corexit is manufactured by Nalco, “a company that was once part of Exxon Mobil Corp. and whose current leadership includes executives at both BP and Exxon,” E&E News reports.

According to The New York Times, EPA data reveals that “Corexit ranks far above dispersants made by competitors in toxicity and far below them in effectiveness in handling southern Louisiana crude.”