CSB Launches Investigation of Fatal Explosion at U.S. Steel Plant

The U.S. Chemical Safety and Hazard Investigation Board (CSB) has launched an investigation into the explosions and fires that occurred last week at a U.S. Steel plant in Clairton, Pennsylvania, about 15 miles outside of Pittsburgh. The incident killed two workers and injured at least 10 others. According to CSB, the Clairton Coke Works facility processes raw coal into coke, which is used in steelmaking. The facility is considered the largest of its kind in North America, with nearly 1,300 workers on site each day. CSB, an independent federal agency charged with investigating major chemical accidents and recommending safety improvements for the chemical industry, “will work to determine the cause of this tragic incident and identify actions that can be taken to help ensure that a similar disaster like this does not happen again,” said CSB Chairperson Steve Owens.

A statement issued by U.S. Steel on Friday describes findings from the early stages of the investigation, which is being conducted by CSB along with the United Steelworkers, U.S. Steel employees, and others.

“Preliminary indications lead us to believe that the explosion happened when flushing a gas valve, in preparation for planned maintenance,” the statement says. “Pressure built inside the valve, leading to valve failure and coke oven gas filling the area and ultimately exploding when finding an ignition source.”

Learn more from CSB’s news release.