An explosion at US Steel's Clairton Coke Works outside of Pittsburgh, Pennsylvania, USA has killed two people, according to media reports. At least 10 people are reported to be injured by the blast and five are in a critical but stable condition. The other five have been released from hospital.

According to Allegheny emergency services, a fire started at the plant in the Mon Valley around 1051hrs on Monday (yesterday) and it wasn't long before a second fatality had been announced.

A report in the UK national newspaper, The Guardian, quoted Abigail Gardner, director of communications for Allegheny county, as saying a search and rescue operation was initiated after the main blast. There were several smaller blasts after the first one. Residents, claims the Guardian report, were warned to stay away from the scene to allow emergency workers site access.

The explosion was 'absolutely tragic' according to John Fetterman, a Democratic Pennsylvania senator who vowed to support steelworkers in the aftermath.

The blast happened at the Clairton Coke Works, which has been part of US Steel and is over 120 years old. The facility supplies coke to US Steel's mill in Gary, Indiana. Over the years there have been many concerns about safety and pollution at the Clairton coke works. There were problems earlier this year when a build-up of combustible material ignited causing an audible 'boom' and resulted in eye injuries for two workers who, it is claimed, were not seriously injured.

Monday's explosion is believed to be the third 'major event' at the plant this year. There was a stack explosion in February and a pollution control room malfunction in June, but no injuries were reported, claims the Guardian report.

While US Steel has made many promises to local residents many have been delayed or abandoned, claimed the Guardian story. There has been little in the way of transparency or 'meaningful community involvement', the newspaper reported.

A report by the BBC claims that five of the injured are in a critical but stable condition. The rest have been released from hospital.

One of the men killed has been identified as 39-year-old Timothy Quinn but the other remains unidentified at the time of writing.

The plant, located 15 miles south of Pittsburgh, is the largest coking operation in North America, employing around 1,300 people helping to produce coke for the production of steel.

Clairton Coke Works has paid out millions of dollars in fines, penalties and settlements in recent years, says the BBC.

Mayor Richard Lattanzi told CBS, the BBC's US news partner, that it was a sad day for Clairton.

Sources: The Guardian Newspaper and the BBC News website.