Todd Barrett was with a crew of laborers at the Clairton coke works that morning when they all felt something. It was an explosion at batteries 13 and 14 at the plant. The batteries consist of dozens of tall,

U.S. Steel Clairton Coke Works' current limited coke-making capacity due to Monday's explosion is prompting concerns.

The Allegheny County Health Department announced that Mobile Air Units will be deployed in the Mon Valley Thursday and Friday as part of an ongoing investigation into the deadly explosion at the U.S.