In a conference call with reporters, Paul Anastas, EPA's assistant administrator for research and development, said the agency was working on such a study. Before making any alterations to its current policy, he said, "we will need to have this additional testing of the dispersants plus the oil."

Dispersants bond to oil molecules and separate them from water molecules, somewhat similar to the way dish soap pulls apart oil and water in a kitchen sink, according to Nalco, Corexit's Illinois-based manufacturer. The dispersed oil then can be broken down more easily by microorganisms in the ocean.

On May 20, the EPA ordered BP to stop spraying Corexit 9500 in the water and find a less-toxic alternative. But the oil company refused, saying the product continued to be "the best product for subsea application." To date, the company has sprayed 1.6 million gallons of dispersant on the ocean's surface and at the site of the blown-out well a mile underwater.

The study released Wednesday measured the effect of Corexit 9500 and seven other dispersants on two Gulf of Mexico species, the mysid shrimp and the tiny inland silverside fish. The results, the agency stated, "indicated that none of the eight dispersants tested, including the product in use in the gulf, displayed biologically significant endocrine disrupting activity."

Disruption of the endocrine system, a sensitive set of regulating glands and hormones, can lead to reproductive problems for numerous species.

Richard Charter, a senior policy advisor for marine programs for the nonprofit group Defenders of Wildlife, said the results of EPA's studies were "inconclusive." He said the federal government needed to investigate whether the use of dispersants has helped form the subsea masses of oil detected by government and academic researchers. Charter and others fear that the oil, when pushed underwater, cannot be defended by the miles of boom laid out to catch oil floating on the surface.

"A fundamental question is…did the behavior of the oil through the use of dispersants make things more complicated at the shoreline response end?"

Other scientists worry about the effect of the oil-dispersant mix on sea life below the surface, including tiny plankton and large marine mammals.

Lisa Suatoni, a senior scientist with the Natural Resources Defense Council, said the "really interesting questions" would be answered after EPA looks at the toxicity of the oil-dispersant mix. But she was concerned that the agency will test its effects only on the same shrimp and fish, hardly representative of the staggering biodiversity in the Gulf of Mexico.

The report was released on a day when another key aspect of the spill response — the use of skimmer boats — was stymied by big swells kicked eastward by Hurricane Alex, which was expected to strengthen from a Category 1 to a Category 2 hurricane Wednesday before spinning into the northeast coast of Mexico, according to meteorologists at AccuWeather.com.

U.S. Coast Guard Petty Officer Kelly Parker said all near-shore skimmers in Louisiana were sent to port because of the high waves, and were expected to take back to the water Friday. A spokeswoman for the response effort in Mississippi, Alabama and Florida said no skimming had been performed in those states.

In Washington, top Obama administration officials, including Interior Secretary Ken Salazar, Coast Guard Adm. Thad Allen and Energy Secretary Steven Chu met with BP officials Wednesday afternoon at the Interior Department to discuss whether they should remove the containment cap atop the broken well and replace it with a better-fitting one.

Switching the cap is risky: Like nearly all of the efforts a mile beneath the sea surface, there is no guarantee that it will work. Moreover, once the existing cap is removed, one of the most effective oil-collection schemes put in place thus far — a riser pipe that sends oil to the production ship Discoverer Enterprise — would go offline. That means as much as 18,000 barrels of oil per day that is being collected would gush into the gulf until the new cap could be put on, said BP spokesman Robert Wine.

The company needs to affix the new cap in order to attach two permanent riser systems, which could take up as much as 50,000 barrels of oil per day and would be less susceptible to storm-related shutdowns, Wine said.

BP hopes to add two other containment systems in addition to these permanent risers, allowing them to collect 60,000 to 80,000 barrels per day.

The government estimates as much as 60,000 barrels per day is spewing from the well. The most the company has collected in any 24-hour period was about 25,000 barrels.

Allen said officials at the meeting would discuss the "risks and tradeoffs" associated with removing the cap. "We want to make sure we know the implications" of removing it, he said.

Allen, selected by the Obama administration to be the "national incident commander" for the massive public-private cleanup effort, officially retired from the Coast Guard on Wednesday but will continue to run the oil-spill response as a civilian employee of the Department of Homeland Security.

In Congress, meanwhile, Salazar faced tough questioning about the Obama administration's moratorium on deep-water drilling, which was overturned by a federal judge, and about the constitution of a presidential panel charged with reforming drilling regulations.

Rep. Paul Broun (R-Ga.) repeated his complaint that only two scientists or engineers sit on the panel, and asked that the group report to Congress as well as to the president. He also alleged that Salazar misrepresented another panel's recommendations about deep-water drilling in order to justify the moratorium.

"The misrepresentation of the peer reviewers' recommendations, in order to justify an offshore drilling moratorium, presents troublesome patterns of how this administration views the role of science and technology relating to this disaster," Broun said.

"With respect to your statement on misrepresentation, let me just say, with all due respect, Congressman Broun, you're wrong," Salazar replied. "The letter, as I have testified in this committee, that I wrote to the president said that we were submitting a set of safety recommendations.…I also in that letter said I was recommending that we move forward with a moratorium. And I believe the moratorium was right then; I believe the moratorium is right today, because we need to learn the lessons."

In the Senate, meanwhile, an attempt to press passage of a measure giving the presidential panel subpoena powers was thwarted by Sen. Jim DeMint (R-S.C.). The measure had passed in the House.

http://www.latimes.com/news/nationworld/nation/la-na-oil-spill-2010...