WASHINGTON — The first round of government tests of the chemical dispersants that are being used to break up the massive oil spill in the Gulf of Mexico found that they aren't overly damaging to shrimp and small fish, but more tests are needed to determine what happens when they're mixed with oil.
The Environmental Protection Agency also said Wednesday that tests on eight chemical dispersants found that they don't damage the body's glands and hormones in ways that can harm development or reproductive, immune and neurological systems.
The EPA also said that BP had reduced the amount of chemical dispersants it was using by almost as much as the government ordered it to do in May. The EPA and the Coast Guard on May 26 told BP to reduce dispersant use by 75 percent from peak use. BP reduced it by 68 percent over the next month.
Paul Anastas, the EPA's assistant administrator for research and development, said the agency wasn't ready to decide whether BP should stop using the dispersant Corexit 9500 to break up the oil and switch to another one. "We have more testing to do," he said.
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The EPA in May said it hadn't yet found that dispersants were harming marine life, but was concerned because BP was using such large amounts of the chemicals. It told BP to find a less toxic and more effective dispersant.
BP said in a May 20 letter in response that it couldn't find a less toxic alternative. It told the EPA that the only other dispersant it had in ample supply, Sea Brat No. 4, can break down into substances that could interfere with the body's glands and hormones.
The EPA said that Corexit 9500 and another dispersant, JD-2000, were generally less toxic to small fish, and JD-2000 and SAF-RON GOLD were least toxic to mysid shrimp, small crustaceans found in the northern Gulf of Mexico.
The next round of tests will examine the toxicity of the oil spewing from BP's broken well and a combination of the oil and each of the eight dispersants.
The data from the first round of tests, Anastas said, show the dispersants degrade in "weeks to months," while oil can remain for years.
The EPA continues to believe that with such a huge oil spill, the dispersants have been useful, but using them was a difficult decision, Anastas said.
Much remains unknown about the effects of the chemicals on living things, including people who work with them, and on the environment.
Still, Anastas said, "the data is telling us that these are not posing the same types of hazard as the terrible hazards we're seeing in the oil."
He said the agency expected BP to continue to seek the least toxic dispersant and minimize its use.
Anastas acknowledged that industry data was part of what EPA used to look at the differences in toxicity among dispersants. He said the agency's recent tests were intended to check those findings.
Asked why it was taking the EPA so long to do the tests, he said: "I think it's very important to recognize that EPA scientists on this project — on all the monitoring that's going on: the sampling, the measuring — our scientists are working overtime. We're going 24/7 to ensure that the best science is being brought to bear and that this is delivered as soon as possible."
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