British Petroleum did not have an emergency response plan for its Deepwater Horizon drill rig; such plans direct personnel to the proper procedures for responding to incidents like the current spill in the Gulf of Mexico.

In testimony before the House Transportation and Infrastructure Committee on May 19, Liz Birnbaum, the former Director of the Minerals Management Service (MMS) who resigned yesterday morning, said the reason that BP did not complete an Oil Spill Response Plan was a reported decrease in  the rig’s “worst-case scenario discharge” from 250,000 barrels a day to 160,000.

BP calculated the volume ...