[willy]

The emergency well valves are not located on the rig itself but on the well head.
And the oil company told the EPA at the time of the explosion that there was a very real possibility of well head leakage but would not be able to confirm immediatly due to the depth of the well (5000 ft).
But the Czarina at the EPA was busy with Earth Day and other commitments. The best equiped vessel in the world was never dispatched, which it could have been on scene in 24-48 hours tops, to date it is still sitting at anchor.