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They must be kidding. To break up the Deepwater Horizon oil spill the dispersants Corexit 9500 and Corexit 9527 are used by the hundreds of thousands of gallons. Right into the ecosystem of the Gulf. But what is it they use?
As ProPublica reported Monday, information about dispersants is “kept secret under competitive trade laws.” I’ve spent the last several days trying to confirm what many in the ocean-ecology and public health worlds seemed to know, but no one would say officially: that two different dispersants sold under the banner of Corexit were being used in vast quantities. The Corexit brand is owned by an Illinois-based company called Nalco, which entered the dispersant business back in 1994, when it merged with Exxon’s chemical unit. (By 2004, Exxon had divested and Nalco was a standalone company, according to Nalco’s company history.)
So, what’s in the stuff? According to their data sheets, both 9500 and 9527 are composed of three potentially hazardous substances. They share two in common, organic sulfonic acid salt and propylene glycol. In addition to those two, Corexit 9500 contains something called “Distillates, petroleum, hydrotreated light,” while Corexit 9527 contains 2-Butoxyethanol. Frustratingly, the sheets don’t give exact information about how much of the substances are in the dispersants; instead they give ranges as a percentage of weight. For example, Corexit 9500 can be composed of anywhere from 10 to 30 percent petroleum distillates, while 2-Butoxyethanol makes up anywhere from 30 to 60 percent of 9527.
Protected under competitive trade laws? My foot, they are dumping it in our ecosystem the more the better and don’t even have to let us know what’s in it? I know, you can already hear me shout: “Regulation!”
There would be an alternative chemical, I seriously doubt that it is really environmentally friendly, but obviously it’s use wasn’t even considered properly.
Called Dispersit, it’s manufactured by the U.S. Polychemical Corporation and has been approved for use by the Environmental Protection Agency. Both Corexit and Dispersit were tested by the EPA, and according to those results, Corexit was 54.7 percent effective at breaking down crude oil from the Gulf, and Dispersit was 100 percent effective.
Not only did Corexit do a worse job of dispersing oil, but it was three times as lethal to silverfish – used as a benchmark organism in toxicity testing — and more than twice as lethal to shrimp, another benchmark organism and an important part of Gulf fisheries.
Relief agencies were not immediately available for comment about Dispersit. In a Tuesday press conference, Charlie Henry, the scientific support coordinator for the National Oceanic and Atmospheric Administration, said the potential effects of Corexit’s use in the Gulf are unknown. “Those analyses are going on, but right now there’s no consensus,” he said. “And we’re just really getting started. You can imagine it’s something we’ve never thought about.” (read more)
Never thought about it? Figures.
You can find more information on the toxicity of Corexit here, here and here.
It is all just a matter of “Now you see me, now you don’t.”
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