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The chemical dispersants that BP poured into the Gulf of Mexico to dilute the oil from its broken well seem to have disappeared. That's what government scientists told a Senate panel today. But many warned that out of sight should not lead to out of mind. As NPR's Christopher Joyce reports, the long-term effects of these chemicals remain a mystery.
CHRISTOPHER JOYCE: BP and the federal cleanup teams in the Gulf had a choice in the early days of the spill: let the oil rise to the surface, form a slick and travel wherever, or use dispersants to break it up. They chose dispersants - almost two million gallons of them. Republican Senator John Barrasso of Wyoming said the circumstances were unforgiving.
JOHN BARRASSO: They leave responders with a catch-22: either you are blamed for dumping chemicals in the Gulf or you allow the oil to devastate the Gulf.
JOYCE: Barrasso spoke at a hearing before a panel of the Senate Environment and Public Works Committee, which is weighing new legislation to regulate the use of chemical dispersants. Those dispersants - BP used two kinds of a chemical called Corexit - are toxic. Government scientists say cleanup workers were warned and took safety precautions. As for wildlife exposed to it? Well, nobody really knows.
PAUL ANASTAS: But what we do know right now is this: We aren't seeing dispersants in our monitoring results.
JOYCE: But scientists who study marine life point out that doesn't mean the chemicals haven't affected life in the Gulf. Among those scientists is toxicologist Ronald Kendall at Texas Tech University, who implored the senators not to think that the worst is over.
RONALD KENDALL: This is uncharted territory. We need science now.
JOYCE: Kendall said what's happening in the Gulf right now is a huge uncontrolled experiment.
KENDALL: Did we really understand the environmental toxicology of such a massive use in the deep water of a substance such as Corexit? And I say we did not.
JOYCE: But toxic is a hard thing to pin down. Tests done before and after the spill looked at short-term effects of dispersants on only a few species of fish and shrimp. Many of those tests were done by the manufacturer, not by government regulators. EPA's Anastas acknowledged that science's work is just beginning.
ANASTAS: I am not suggesting that we have perfect knowledge. I am not suggesting that we don't need more information and more monitoring. I am actually saying straight out that it is important to keep on asking these hard questions.
JOYCE: Dana Wetzel is a chemist who spent years studying dispersants at the Mote Marine Laboratory in Florida.
DANA WETZEL: We cannot just sweep this under the rug and say, okay, we're collecting all the oil, and it's going away. We really don't have all that much to worry about anymore. I contend that that's absolutely so wrong.
JOYCE: A lot of oil was not collected or burned off and could remain under the Gulf in great clouds of oil and dispersant. Wetzel says the potential long-term effects of this chemical cocktail on everything from coral reefs to whale sharks are unknown.
WETZEL: Will they reproduce as they normally would? Will they have the same number of offspring? It doesn't end there. Will those offspring reproduce? You know, is their immune system compromised?
JOYCE: Christopher Joyce, NPR News.
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