The union vice president at U.S. Steel Clairton Coke Works is shedding new light on what led to the deadly explosion and the active effort to save the damaged batteries. 

U.S. Steel shared that preliminary findings indicate that pressure building inside a gas valve led to its failure. Richard Tikey, the vice president of USW Local 1557, said as he understands it, contractors "significantly overpressurized" the valve with water as they were flushing it ahead of planned maintenance, causing the valve to split, releasing gas that would eventually ignite. The exact cause of the explosion is still under investigation. 

The contractors, who work full time at the plant, are not USW members, Tikey added. One union steelworker was there in a supporting, not active role. 

The valve itself was last replaced in 2015, Tikey said. He does not believe the explosion was due to old equipment. 

Since the explosion on Aug. 11, crews have been working around the clock to save the batteries, which were damaged, multiple steelworkers said. Their coke ovens usually sit at 2,300 degrees. But without gas to heat them, they have been down to 1,400 degrees.

"The border of losing [the] ovens" is 1,200 degrees, Tikey said. 

Should it cool down enough, it could force them to rebuild entire batteries, a lengthy and costly process, Tikey said. In the short term, he said they need to have some heat back on by Monday or there could be issues. 

A workaround is in the works that, in just days, could allow them to manually add gas, bringing limited heat to the ovens — enough to prevent further damage, Tikey said. 

"They're setting up a temporary reversing room right now," Tikey said. "It's going to be a while before that battery is actually in operation. I'm talking three, four months minimum." 

The reversing room is where multiple steelworkers have told KDKA is the location where the valve that U.S. Steel says failed.

There have been fears from steelworkers that there could be layoffs due to the battery being down, but he's been assuring them that Nippon Steel, the company's new owner, has promised no layoffs for at least a decade. 

Tikey remains grateful that more people were not hurt during and after the explosion. He thanked first responders, steelworkers and management. 

"It was a tragedy that had happened. It was a hot day, and we all came together and worked as a team," Tikey said. 

Tikey also addressed what multiple steelworkers say they have heard secondhand, that there were warnings, and U.S. Steel for a month knew something was wrong.

Tikey said there was a leak in the area of the explosion, but that it was corrected with a patch and did not lead to the explosion, to his understanding. He added that U.S. Steel had monitors to watch for any leaks.

Editor's note: This story has been updated to clarify that the workers who overpressurized the valve are not represented by the USW union.