They probably didn't know about these microbe's effectiveness. That, and there was so much publicity about the problems that they had to do ~something~ --- doin

They probably didn't know about these microbe's effectiveness. That, and there was so much publicity about the problems that they had to do ~something~ --- doing nothing would have been taken even worse by the public. Seriously, imagine BP saying, "uh ... yeah, there's not a problem, billions of tiny microbes are going to take care of our accident." People would have mocked them plenty, and their PR guys wouldn't want that.