Firefighters responded to a blaze inside an unused section of the Universal Stainless Steel plant in Collier Township over the weekend, but were able to stop it from spreading.

Kirwan Heights fire Chief Mark Lewis said crews responded to the fire shortly before noon Saturday and contained it to an old shipping office before it could spread elsewhere.

Only the room’s contents, which included a desk, chairs and papers, were destroyed. Workers at the plant noticed smoke billowing from the room and called emergency responders. Firefighters had to locate the fire in the sprawling complex.

“It was a smoky fire, so when you came down into the complex, you could see where the fire was coming from,” Lewis said. “It’s a catacomb maze down there.”

Firefighters removed debris in the room and coated the walls with a specialized foam to make sure the fire did not rekindle.

A cause of the fire has not been determined.

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