LISBON – Ten firetrucks from eight fire departments and four medical units were called to assist Lisbon and Lisbon Falls firefighters at a stubborn fire at the Knight-Celotex mill Saturday afternoon.

The mill is on Route 196 at the Lisbon Falls-Tospham town line.

First reports of smoke at the sprawling mill, located on the banks of the Androscoggin River, came in at 1:40 p.m. as temperatures soared.

Within an hour, firetrucks from Brunswick, Topsham, Sabattus, Bowdoin, Lewiston, Freeport, Bath and Durham responded to the scene. Medical units were from Lisbon Emergency and United Ambulance.

Police closed the bridge from Durham to Lisbon and closed Route 196 to all traffic between the Main Street and Canal Street intersection to Summer Street, across from the mill.

A representative from the State Fire Marshal’s Office was at the scene Saturday night.

The Lisbon Falls plant has manufactured fiberboard since 1984. The mill is also known as the former U.S. Gypsum Co., a firm that produced wood fiber products, later owned by Masonite Corp.

Last December, Masonite sold the facility to Knight-Celotex, which is based in Chicago. Knight-Celotex is a leading manufacturer of insulation sheathing, sound deadening and roofing fiberboard for the residential and commercial construction industry.

Knight-Celotex had been working with Androscoggin County and state officials to create collaborative partnerships to strengthen the competitiveness of the Lisbon facility.

According to Lisbon Development Director Dan Feeney, the firm has 125 employees and was in the process of hiring back employees that had been laid off by Masonite. Voters at the annual town meeting Monday night will be considering an article to designate the Knight-Celotex 23.84-acre parcel as a Pine Tree Zone.

As of press time Saturday, there was no immediate information on the cause of the fire or how badly the mill was damaged, although bystanders said the damage appeared to be extensive.

Saturday’s fire was reminiscent of the steamy July day in 1987 when the nearby Worumbo Mill fire began. The Worumbo blaze was the largest mill fire ever in the state and drew firefighers from as far away as Saco. That fire was still smoldering a week later.