Many news reports are suggesting that gas valve failure might have been the cause of US Steel's Clairton Coke Works explosions last week that saw two workers dead and 10 injured at the facility near Pittsburgh in the USA.

One report, from KBTX, claimed that preparations for a routine maintenance task may have led to an explosion, based on initial information received from investigators and from reviewing video footage and interviewing US Steel employees working at the facility.

It is being suggested that the explosion happened when workers were flushing a gas valve in preparation for routine planned maintenance tasks.

According to the KBTX report, "The explosion, which heavily damaged part of the sprawling facility, started around a set of ovens where coal is baked to 1,200 degrees Fahrenheit (648.89 Celsius) into a more efficient carbon fuel called coke, a key component in steelmaking. A by-product of processing the coal is a combustible gas called coke oven gas, made up of a lethal mix of methane, carbon dioxide and carbon monoxide."

As pressure built up inside the valve, is it being suggested, the valve failed resulting in the escape of coke oven gas and the explosions.

Why pressure built up inside the valve or what was the ignition source was not discussed by USA. The investigation, the company said, was in its infancy. More information will be made available as and when and so far there has been no comment from the United Steelworks union Local 1557, which represents the workers killed and injured.

Bernie Hall, a United Steelworkers representative in Pennsylvania, District 10, told KBTX that it was working to seek answers, adding that the investigation was in its early stages and, therefore, more needed to be learnt before speculating further.

US Steel didn’t say why pressure built inside the valve or what was the ignition source. The investigation, it said, was in its early stages. The company said it will provide more information when it can.

The Clairton facility, which is almost 110 years old, is widely regarded as the largest coking operation in North America and forms part of just a handful of integrated steelmaking operations active in the USA where the predominant form of steelmaking (over 70%) is based on the use of electric arc furnaces (EAFs) - making the USA steel industry one of the greenest, if not THE greenest in the world.

Source: KBTX.