The EPA has been testing air and water for compounds from both types of Corexit that were purportedly used in the spill (certainly Corexit 9500 was used, but there is some question whether the 9527 was used).
Said EPA data shows "ND" for all tests (ND standing for "Not Detected"). You can find the values for those compounds in water tests at the following URL.
http://www.epa.gov/BPSpill/data/water_dispersants.pdf
The other inconvenient fact for your doomsday scenario is that both types of Corexit are NOT STABLE once put into aqueous solution. They decompose with a half-life of around 10-20 days. So much of the Corexit put in the Gulf is simply GONE.
Well damn...how are we going to keep the Gulf toxic with that half-life?
You are a hopless brainwashed shill, Warthog. Now we all know. Thanks.