WASHINGTON — The Environmental Protection Agency on Thursday ordered BP to switch to a less toxic version of the chemical dispersant it's been using in huge quantities in the Gulf of Mexico to break up its spreading oil spill.
An EPA directive to the oil company told it to find a less toxic alternative to Corexit, the dispersant it's used so far. The company has applied 600,000 gallons of the chemical mix on the surface of the water and another 55,000 gallons some 5,000 feet below the surface at the site of the leak. Such a large use of any dispersant and its application deep underwater are unprecedented.
The EPA said BP must find a less toxic alternative in 24 hours and start using it three days after that.
Before the spill, the EPA had approved the use of Corexit and other dispersants three miles offshore in deep water. For a time after the spill, the EPA told BP to halt its use deep underwater while the agency tested it. Later, it allowed BP to resume its use.
In ordering the halt Thursday, the agency said that BP should use the least toxic product because so much was unknown about using chemical dispersants in such large amounts and so far below the surface of the water.
McClatchy reported May 6 that Corexit was being used on the spill with scant understanding of what damage it might be doing.
Dispersants act much like dish detergent, breaking up oil into smaller particles and sending it down into the water. Dispersants are used to prevent the oil from staying on the surface and moving toward shore. Scientists say it's a trade-off between protecting the shore and exposing life in the ocean to a toxic mix of dispersants and oil.
The EPA also made BP's data about the use of dispersants under water public Thursday. The agency said the findings didn't show any significant effects on marine life. The data also showed that the oil droplets got smaller, an indication that the dispersant was effective.
"EPA is working closely with its federal partners, including the U.S. Coast Guard and NOAA, to ensure an aggressive dispersant monitoring plan is implemented by BP and that data are regularly and rigorously reviewed," the agency said in a statement, referring to the National Oceanic and Atmospheric Administration.
It also said that oxygen levels in the water remained "in the normal range." Oxygen levels could decline as oil-eating bacteria go to work on the dispersed oil.
Rep. Edward Markey, D-Mass., had written Monday to EPA Administrator Lisa Jackson expressing concerns about the toxicity of Corexit.
"I commend the Obama administration for acting swiftly to address my concerns that the dispersant BP chose to use is more toxic than other available formulations," Markey said Thursday in a statement. "The effect of long-term use of dispersants on the marine ecosystem has not been extensively studied, and we need to act with the utmost of caution."
MORE FROM MCCLATCHY