UPDATE: June 29 In the interest of integrity and maintaining factual data, I will always update and post corrections as I learn new information on a topic. To that end, the information in the original post below was sent to me from a university professor (originally from Rep. Markey) and, while the original information is factual and Corexit is a toxic product, the below information shows a slightly more straightforward interpretation, and I felt it important to share.

Thanks to my brother, the engineer, for the correction regarding UK’s “rocky shores test” (and for keeping ME honest):

From my understanding, the “limpet test” a.k.a. “rocky shores test” that is performed by the UK is primarily an evaluation of the ability of the limpet to adhere to a rock surface after exposure to a dispersant.  The inability to adhere is a result of the slipperiness caused by the surfactant in the dispersant.  “For the purposes of the test”, the limpet is assumed dead if it is unable to adhere to the rock after exposure.  This is because a crustacean that is unable to adhere to the rock will likely die due to any of a number of causes including wave action, predation, etc.

While the negative effects on crustaceans are certainly of concern, the test result implies no toxic effects on other creatures OR on any creatures in areas where rocky shores are not present.  In fact, the ban in the UK applies only to use of the dispersant in areas of rocky shores and has no effect in offshore applications (3 miles out and further).

Additionally, it’s important to point out that the UK ban on Corexit is specifically for rocky shoreline conditions and that (referencing Corexit 9500 and 9527): “Existing stocks of these products may still be used away from rocky shorelines in appropriate conditions.”

We have no idea how the UK would respond to BP’s unprecedented Corexit use in an oil catastrophe the size of BP’s Deepwater Horizon, nor do we know how much “existing stock” of Corexit is left there. I’m quite certain, based on the “rocky shores” ban that BP would not be allowed to spray Corexit aerially over a residential area, such as Barataria Bay, as many rumors out of Louisiana have indicated happened there. However, always presenting you with the full story, below is the original post.

Begin Original Post:

These are the results of the UK “Rocky Shore test” which is a requirement for dispersant approval in the UK and was failed by the Corexit products currently being used in the Gulf. In this test, a type of snail, the common limpet, is sprayed with oil alone (which is highly lethal) or with dispersant alone, and the number of snails that lose adhesion (which for purposes of the test are considered to be dead) are counted. If you look at the numbers in this test you will see that Corexit alone is twice as lethal as oil.

Thanks to Rep. Ed Markey & his staff for making this information available (thanks to Bill Buckley for sharing):