HARRISBURG, Pa. (AP) — Preparations for a routine maintenance task may have led to an explosion at a U.S. Steel coal-processing plant near Pittsburgh that left two dead and sent 10 to hospitals, the company said Friday.

An explosion at a U.S. Steel plant south of Pittsburgh killed two people and injured more than 10 others. The CEO has vowed to find out what caused Monday’s blast while the workers’ union says it will make sure there’s a thorough investigation.

Crews are working to restore operations after the deaths of two employees.

The explosion, followed by several smaller blasts, could be felt in the nearby community and prompted county officials to warn residents to stay away from the scene so emergency workers could respond.

The Trump administration on Friday widened the reach of its 50% tariffs on steel and aluminum imports by adding hundreds of derivative products to the list of goods subject to the levies.

Family members tell Pittsburgh's Action News 4 Steven Menefee, a father of two, was a loving man who would give you the shirt off his back.