U.S. Steel says its preliminary investigation found that the blast happened after pressure built up while a gas valve was ...

Allegheny County is increasing air quality monitoring after an explosion at a U.S. Steel plant south of Pittsburgh killed two ...

Workers were heating coal and preparing for routine maintenance when an explosion rocked a U.S. Steel plant outside ...

An explosion at a steel plant in Pennsylvania on Monday has led to an extremely serious situation. The explosion at the plant ...

Preparations for a routine maintenance task may have led to an explosion at a U.S. Steel coal-processing plant near ...

Repairing Clairton, however, could be expensive, an investigation into the explosion could turn up more problems, and an ...

The mill, which is part of the recent merger between U.S. Steel and Nippon Steel, has faced scrutiny from federal and local ...

Authorities said their investigation has shifted to the cause of the explosion after they accounted for everyone who was missing.