UPDATE: Dispersants Less Toxic Than Oil; More Study Needed-EPA

30th Jun 2010 21:20

(Updates with comments from an EPA official and additional details throughout) By Cassandra Sweet and Mark Long Of DOW JONES NEWSWIRES U.S. environmental regulators said Wednesday that none of eight oil dispersants it tested, including the one being used to break up the Gulf of Mexico oil spill, significantly disrupts the vital endocrine systems of marine creatures, although more study is required. The agency cautioned that the results were preliminary and that testing currently underway will provide better data to determine how toxic the chemical dispersant BP has been using is compared with alternatives. On May 20, the agency ordered the company to find a less-toxic alternative to the dispersant it was using, Corexit 9500. But after BP said that less-toxic dispersants were not available in quantities necessary to fight the spill, the agency relented and instead told the company to cut back on its use of the dispersant. Since late May, BP has cut its use of the dispersant by 70%, said Paul Anastas, EPA assistant administrator for research and development. "This is the first round of data," Anastas said, speaking with reporters by telephone. "We need more data in order to determine whether a change in dispersants is necessary." Anastas declined to discuss why the EPA reversed its initial request for BP to stop using Corexit, except to say that, "we expected them to pick the least-toxic dispersant and always be asking that question and look to identify that." More than a million and a half gallons of chemical dispersants have been used to break down the millions of barrels of oil that have gushed into the Gulf over the 10 weeks since the Deepwater Horizon burned and sank, springing the leak, in late April. Use of the chemicals has raised fears of damage to aquatic life, in particular to the endocrine system that regulates reproductive and neurological development in animals. "Dispersants are generally less toxic than oil and can prevent some oil from impacting sensitive areas along the Gulf Coast," Anastas said. He said government scientists continue to perform independent tests to determine the potential impacts of the dispersants and will conduct additional research before making a final recommendation on their use. Anastas emphasized that oil is more toxic than any of the dispersants. He also said scientists haven't seen "concentrations" of dispersants remaining underwater or settling to the sea floor. All of the eight dispersants tested, including Corexit 9500--the one used by BP thus far--showed roughly the same effects in tests when not mixed with oil, the EPA said. However two dispersants--JD-2000 and Corexit 9500--proved least toxic to small fish, while JD-2000 and SAF-RON GOLD were least toxic to the mysid shrimp. Nalco Co., the company that makes Corexit, has said the dispersant is safe. It takes a few weeks for dispersants to break up oil into smaller droplets which are then degraded by micro-organisms. The process takes less time in warmer water near the surface than in colder, deeper water, Anastas said. The EPA said its next stage of testing will assess the toxicity of the Louisiana Sweet Crude Oil that's leaking into the Gulf, as well as combinations of the crude with each of the eight dispersants. Testing each dispersant mixed with oil will yield more definitive results about their toxicity, Anastas said. Those tests should be completed in the next few weeks and will serve as the basis for any future decisions the EPA makes on ramping down the use of dispersants or which dispersants will be used, Anastas said. -By Cassandra Sweet and Mark Long, Dow Jones Newswires; 415-439-6468; [email protected] (END) Dow Jones Newswires June 30, 2010 16:20 ET (20:20 GMT)