PITTSBURGH (KDKA) — The fire that damaged the Liberty Bridge and detoured traffic for 24 days was started by work that city officials say the contractor did not have a permit to perform.

Pittsburgh Fire Chief Dr. Darryl Jones says Joseph B. Fay Co. never applied for the permit required to do “hot” work on the bridge. He says the investigation indicates a worker was cutting steel and “hot slag dropped down on a cache of PVC piping, which was on a deck below where they were working.”

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Chief Jones says PVC pipe is highly flammable.

“We call that solid gasoline, because it’s petroleum-based, and once it burns and gives off acrid smoke a lot of flame and a lot of heat,” the chief said.

It was that heat that warped the steel chord of the bridge and forced its closure.

Fay Construction’s Vice President of Operations Dennis Watkins declined to talk about the specifics due to the ongoing OSHA investigation.

But he did say, “We had a safety plan in place. Obviously, we’re going to enhance it a little bit. We had fire watch in our plan; we had a great safety record.”

Chief Jones says when the fire happened there was no “fire watch” present.

“Usually, that means they’re going to have a guy with a fire extinguisher standing by to get the fire while it’s relatively small. This did not happen in this case,” he said.

In fact, he went on to say, “By all the reports that I read from the battalion chief and the deputy chief, there was no fire suppression equipment up there at all.”

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The chief says Fay has been cited for not getting the needed permit and it will be up to a magistrate to decide if the company will be fined. But the chief points out the process of getting the permit could have prevented the fire in the first place.

He says the $16 permit process includes an inspection of the job site and he’s confident his inspectors would have red flagged the highly volatile PVC pipe and had it moved.

“I have no doubt in my mind they would have seen the potential for the danger there,” Chief Jones says.

The chief doubts the worker doing the cutting even noticed the burning PVC pipe until the fire was well underway.

The top executives of Fay didn’t want to discuss the fire or penalties because the investigation is continuing. They did, however, detail the extensive effort that went into repairing the bridge and getting it reopened.

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Most importantly, Executive Vice President Jim Wilkinson wanted to reassure the public.

“It’s safe and we’re back to work on the bridge, and we would not be putting our workers at risk if we thought there was any risk involved,” he said.

Watkins said of the repair now in place around the damaged chord, “All the load is being carried in that jack frame right now, and it’s designed to carry two times the capacity of the original member.”

Fay was able to keep working on other areas of the bridge while the repair work was underway so the overall schedule has only been delayed by a few days.

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Watkins says, “All lanes of the Liberty Bridge will be restored by the end of October.”