WBRZ - Baton Rouge

Crews are pumping cement into BP's blown-out oil well thousands of feet below the sea bottom, working to permanently seal the runaway well.

Engineers initially had planned to pump in mud before the cement, but a BP spokesman said that would not be necessary. There was no pressure building inside the well, so the mud wasn't needed.

BP expects that the well will be completely sealed - and declared permanently dead - sometime Saturday.

The catastrophe began April 20, when an explosion killed 11 workers, sank a drilling rig and led to the worst offshore oil spill in U.S. history.