Investigations need to happen. Drilling so deep is an inherently dangerous activity and if there is merely negligence, I am uncertain as to if there should be criminal penalties. I mean, really, what is the DUTY here for even a negligence calculation? Who are you going to ask other than the people who were doing it? You're going to ask ME (If I were on a jury.) if using 6 centralizers as opposed to 21 is a breach of duty? Please.
Yet, because it is so dangerous, I have no problem of per se negligence standard and BP needs to pay for the damages proximately related. (Which, in my mind would not include the people who are out of work due to presidential fiat for no scientific reason.)
If, after a reasonable investigation, it is found that certain people were RECKLESS in their behavior or choices, then criminal responsibility for the death and destruction is entirely appropriate. Not for the officers of the corporation (Unless the reckless orders came from them.), but for the people involved.
Any other standard, and you might as well get your bikes lubed with vegetable shortening as you're not going to have enough gasoline to drive anywhere.
Info edit:
For one reason why international assistance is being refused, look at the Jones Act. Thanks again, unions! Of course, it could be waived by the administration. I wonder why it hasn't been done yet?