HARRISBURG, Pa. (AP) — Preparations for a routine maintenance task may have led to an explosion at a U.S. Steel coal-processing plant near Pittsburgh that left two dead and sent 10 to hospitals, the company said Friday.

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 released preliminary findings about the potential cause of the deadly explosion at U.S. Steel Clairton Coke Works on Monday.