COREXIT Dispersants EC9527A and EC9500A

14 May

Apparently both Corexit products are being used in the gulf spill, so I’ve linked to both MSDS sheets from the EPA listing


Its interesting to note, EC9527A was originally listed in 1975, and apart from the proprietary ingredients, lists as solvents, water, and a main ingredient of the cleaner Simple Green and another of stick deodorant. It also has a much higher concentration of heavy metals than does the apparently newer dispersant EC9500A.

Do bear in mind, the MSDS sheets are for the material in concentrated form, such as a worker might encounter, rather than the dilute form of a few gallons/acre. Also bear in mind when it says non-hazardous, it is specifically referring to flammability during transport such as what law enforcement or firemen might encounter, not necessarily when actually deployed at sea. Ie, it would be bad to swim in the deployed stuff. Otoh, I must admit I personally find no qualms about using 2-Butoxyethanol (Simple Green) in my parts washer when I do brake jobs and engine work on my personal car, but then again, exposure is very much time limited, and happens only once or twice a year.

That being said, the LC50 (lethal concentration) of both materials, while being better than fuel oil, is not that much better. Worse, however was the combination of the dispersant and the fuel oil. A lower LC50 is more toxic. On the other hand, they only publish test data on a couple marine invertibrates, an Atlantic/Inland Silverside (sort of a large minnow creature) and a Americamys bahia??(a tiny odd looking shrimp like creature) so much is unknown, at least from the MSDS.

I did find another paper on COREXIT dispersant toxicity,?? while there is more data, the paper concludes there is great variabiity depending upon conditions, and that live data under actual conditions of particular use is really the only way to go…

Sadly that means we have to rely on either A Nalco’s word, B, the govt, or C some enterprising individual could run some tests on whatever washes up on shore. Granted, C, unless a university backs them would likely not have much credibiity… but hard data, even if captured by a 14 year old would seem of value in this age of trying to cover up, hide this or that, or deny, if it came up with similar readings as to what others were saying.



One Response to “COREXIT Dispersants EC9527A and EC9500A”

  1. Rich Metzler July 29, 2010 at 11:07 pm #

    Ron, This is some excellent info…and scary at the same time

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