NEW YORK -- One person died and dozens of people were hurt after an explosion on Monday at US Steel's Clairton Coke Works in the state of Pennsylvania, US media reported.

Two are believed to be unaccounted for, ABC News reported, quoting Allegheny County police.

The blast trapped people under rubble, prompting a rescue operation, county officials said.

The exact number of victims is not clear but many of the injuries are non-life-threatening, Allegheny County Emergency Services spokesperson Kasey Reigner said.

"The scene is still active, and folks nearby should follow the direction of local authorities," Pennsylvania Governor Josh Shapiro said on the social media platform X.

The Allegheny County Health Department is advising residents who live within a mile of the plant to stay inside, close all windows and doors, and avoid activities that draw in outside air, local TV channel WTAE-TV reported.

The Clairton plant has been dogged by concerns about pollution in recent years. In 2019, US Steel agreed to settle a 2017 lawsuit for 8.5 million US dollars. Under the settlement, the company agreed to spend 6.5 million dollars to reduce soot emissions and noxious odors from the Clairton coke-making facility, according to media reports.