EPA defends use of dispersant in Gulf oil spill response

The Environmental Protection Agency on Monday defended BP’s widespread use of an oil dispersing chemical in the Gulf of Mexico, releasing test results that show mixtures of dispersants and oil are generally no more toxic to two aquatic species than oil alone.

BP’s use of the dispersant Corexit 9500A with federal approval is a politically charged issue. Environmentalists and some lawmakers allege officials allowed massive applications despite unknown risks to marine life and cleanup workers.

{mosads}But Paul Anastas, who heads EPA’s Office of Research and Development, said the decision to allow dispersant use was sound given the dangers posed by the oil that spewed uncontrolled for months from BP’s ruptured well.

He called the oil “enemy No. 1,” and said that test results show the dispersant use “seems to be a wise decision and the oil itself is the hazard that we are concerned about.”

Anastas spoke on a conference call with reporters about newly released testing data. EPA said peer-reviewed tests using eight dispersants on two aquatic species — the mysid shrimp and a fish called the inland silverside — showed various oil-dispersant mixes were generally no more toxic than oil alone, and Corexit mixed with oil is no worse than mixtures of other dispersants and oil.

“For all eight dispersants in both test species, the dispersants alone were less toxic than the dispersant-oil mixture,” states an EPA summary of the results. EPA found Corexit is “is no more or less toxic than the other available alternatives.”

EPA in May had pushed BP to seek a less-toxic alternative to Corexit, but BP continued to use the substance, arguing a less dangerous product was not available.

The test results come days after a senior House Democrat released data showing the U.S. Coast Guard routinely allowed BP exemptions to a May 26 federal mandate to curb surface use of Corexit except in “rare cases.”

Rep. Ed Markey (D-Mass.), in a July 30 letter to National Incident Commander Thad Allen, said more than 74 daily exemption requests were approved for surface application. The letter from Markey, a senior member of the Energy and Commerce Committee, says much remains unknown about the risks from application of a total of more than 1.8 million gallons above and below the Gulf surface.

This has led to a “toxic stew of chemicals, oil and gas with impacts that are not well understood,” Markey wrote.

But EPA on Monday said the May 26 order it issued with the Coast Guard requiring BP to cut total surface and subsurface use by 75 percent had been successful. Dispersant use essentially ceased after the gushing well was capped July 15.

“Dispersant use virtually ended when the cap was placed on the well and its use dropped 72 percent from peak volumes following the joint EPA-U.S. Coast Guard directive to BP in late May,” EPA Administrator Lisa Jackson said in a prepared statement Monday.

“We have said all along that the use of dispersant presents
environmental tradeoffs, which is why we took steps to ensure other
response efforts were prioritized above dispersant use and to
dramatically cut dispersant use,” she said.

Anastas defended the use of dispersants Monday.

“We do believe that use of dispersants was one important tool in the overall response to this tragic oil spill,” Anastas said, but he and other EPA officials also acknowledge “tradeoffs” and say continued monitoring is needed.

“What we also need to recognize is that we want to, and intend to, better and more fully understand all of the possible consequences of this tragic oil spill, and we know that we don’t take adding large quantities of a chemical formulation into the Gulf lightly,” Anastas said.