An explosion at U.S. Steel's Clairton Coke Works outside Pittsburgh killed two people and sent at least 10 to area hospitals Monday, heavily damaging part of the sprawling Mon Valley facility and sending a plume of black smoke over nearby neighborhoods, officials said.
What Happened: Allegheny County authorities said the blast and ensuing fire began around 10:50–10:51 am, prompting a large multi-agency response and a brief "stay indoors" advisory that was later lifted after monitors detected no exceedances of soot or sulfur dioxide, according to a WTAE-TV report.
