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

The deadly blast at the U.S. Steel facility outside Pittsburgh was just the latest in a series of recent workplace accidents.

U.S. Steel's Clairton Coke Works — long flagged for safety and environmental concerns — is under fresh scrutiny after an explosion killed two workers this week. The big picture: Once a defining part of the Pittsburgh region's economy,