If you're weaving down the road at thrice the limit with a fifth in one hand and run someone over, you're going to jail and likely to be sued by the victim or their family. If you're doing well under the speed limit in a licensed and insured vehicle and obeying all the traffic laws you're far less likely to run someone over--but while you might not go to jail if it happens anyway, you're still gonna get sued by the victim or their family. In fact, in both cases you're likely to get sued by their health insurer, too, who'll probably take the view that if YOU broke their leg YOU (not the insurer) should pay to treat them. You may not have done anything WRONG, but you are LIABLE.

I'm in no position to say whether or not BP is simply liable or actually criminal in this case (though I strongly suspect at least criminal negligence. ) That's why we have courts. But it was their equipment operated by their personnel under their managers supervision on land they leased. Who else should be responsible for as yet unknown damages...?