Emergency crews are on the scene of a reported explosion at the U.S. Steel Clairton Coke Works. There are multiple injuries, and multiple medical helicopters have been called to the scene. A mass casualty incident has been declared to allow for additional EMS resources from across the region to respond.

An explosion Monday at a U.S. Steel coking plant near Pittsburgh has left people trapped under the rubble, with emergency workers on site trying to rescue them, an official said.

A rescue operation is underway for people trapped under rubble following an explosion at a Pennsylvania steel plant, officials said.