Prove it. Where are the tests, smarty pants?
No tests needed. We know what the half-lives of the CoRexit components in sea water are (available in peer-reviewed literature which can be accessed online) I posted links to them when the spill was ongoing, so I'm not going to bother to do so again. We also know the date when the last Corexit was used (also available online). MANY half-lives of even the longest half-lived material (21 days) have passed since that time.
The Corexit IS GONE...period. This is a VERY simple judgment that any chemist (I are one...PhD type) would agree with.
If there are any samples being found today "contaminated" with CoRexit, the more likely explanation is that they have been "salted" by the eco-commies. This is a common tactic used by them. See "lynx hairs" in Washington State, and many similar incidents.