CLAIRTON, Pa. (AP) — Workers were pushing coke out of huge ovens and preparing for maintenance when an explosion rocked a U.S. Steel plant outside Pittsburgh, a company executive said Tuesday, a day after the blast killed two workers.

The deadly explosions that happened Monday at U.S. Steel's Clairton Coke Works facility come following several different incidents at the plant over the past several years, including one incident in February. A flaring and fire at the Clairton plant in February sent two people to the hospital.