U.S. Steel has released new details on what investigators believe caused the explosion at the Clairton Coke Works plant that killed 2 people and injured 10 others.

Multiple people have been injured in Pennsylvania, and several medical helicopters have been dispatched to the area.

Brian Doyle remembers the explosion that hurled him to the coke plant’s floor — but little else from that day. It was a Wednesday — July 14, 2010 — and Doyle, a steamfitters union member and contractor for Power Piping,