The preliminary findings say how the company believes the explosion occurred. A union statement cautioned the investigation is in its early stages.

The deadly explosion at Clairton Coke Works near Pittsburgh occurred when a gas valve was flushed before planned maintenance, U.S. Steel said in preliminary findings.

State news agency RIA Novosti has reported that a gunpowder workshop at the facility caught fire and triggered an explosion.

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

Two children were severely injured following an explosion Sunday evening on O'Neil Street, according to the city's firefighters' union. The explosion occurred around 6:07 p.m., according to a Facebook post from the Troy Uniformed Firefighters Association,

CLAIRTON, Pa. — A community rocked by a deadly explosion is coming together to heal. “As a community, we can come together and remember,” one community member said. Now on 11 at 11, reporter Frederick Price brings you inside the prayer service that hopes to lift up the entire Mon Valley.

A tanker truck caught fire Saturday morning on the US-90 Alternate entrance ramp at Fondren, according to the Houston Fire Department.