Tony Hayward used the old "I don't know" and the "investigation is incomplete" defense before the Congressional Committee today. This is 59 days after the blowout and the Board doesn't have the information? Nonsense, of course.

The dispersant used by BP may cause as much damage as the crude oil itself.
I cited this paper in the other thread, "Acute Aquatic Toxicity of Three Corexit Products: An Overview" by researchers with Exxon Biomedical Sciences, Inc.
The dispersants are the most toxic tested by the researchers.

Acute Toxicity

Exxon set up this company at arms-length so that its research would not be hindered by main company management or company association.
It is one of the reasons Exxon had only one culpable infraction and BP had many hundreds.

I understand that Chevron does much the same by placing research funds into arms-length programs at various universities; their violations have been few as well.