They did but they failed!
Could the failures have been prevented? Maybe. Did the safety record of the previous drills in the Gulf give rise to a measure of complacency, probably! Something in excess of 30,000 drills in the Gulf without an accident.

Quote Originally Posted by Carpe Coma View Post
You know, if they did have a backup plan there would be people then making the argument; "They knew this could happen yet they were drilling anyway. Bad bad oil companies".

I seriously doubt they didn't have any emergency plans, instead I bet they just did not have plans for any (every) possible situation. The number one rule of contingency planning is that you can't plan for every contingency.