SOMERSWORTH — Officials are investigating a fire that destroyed a former mill building in Somersworth.

At 8:27 p.m. Monday, emergency rescue crews received multiple 9-1-1 calls reporting a fire at the former Great Falls Bleachery and Dye Works near Main Street.

As fire crews left the station on Maple Street, a lieutenant saw a glow in the sky and ordered a box alarm to summon off-duty personnel and a first alarm to call firefighters from Dover, Rochester, Durham and Berwick, Maine, for help.

A second alarm was called when fire crews arrived at the scene at 8:32 p.m. and they could see the building was engulfed in flames. More firefighters from Newington, Rollinsford and Maine arrived.

Fire Chief Keith Hoyle said they attacked the fire from three sides. Hoses were stretched from Main Street to supply crews with water.

As the fire burned for hours, people living in the vicinity stood outside and watched. Embers from the blaze rose into the air and rained down on Main Street but no other structures caught fire.

Hoyle said just after 11 p.m. the situation was safe enough for people to stay in their homes overnight.

“There’s no hazardous material in the warehouse that we’re aware of. And there’s no natural gas of LP gas in this area, so as of right now, the residents are fine,” Hoyle said.

Hoyle said workers had been in the building earlier in the day. Chinburg Properties owns the structure, which was scheduled to be renovated to create apartments.

On Tuesday, Hoyle said the point of origin and cause of the fire were still under investigation. As far as he knew, nobody had been living there.

“Kids and young adults partied there. Since Chinburg took over the structure they have been securing it and the kids tear off the coverings and go in anyways,” Hoyle said.

Capt. Russell Timmons of the Somersworth Police Department said they had not received any reports of homeless people taking shelter from the cold in the building.

“There’s always a potential, but to say people had gone in there and tried to homestead wouldn’t be accurate. If we did have contact with anybody, they were explained the error of their ways,” Timmons said.

Timmons said there have been destructive fires at “The Bleachery” in the past, in 2003 and 2007, both caused by juveniles who were charged and sent through the court system. Notable historical items were destroyed in those blazes, he said. He said he did not know if anything of historical significance was in the building that burned Monday night.

Timmons said when he started with the police department in 1981, “The Bleachery” was a bustling place where workers dyed huge pieces of material. It has since shut down.

Somersworth Mayor Dana Hilliard commended the work of firefighters.

“The Somersworth Fire Department and surrounding departments demonstrated heroism throughout the evening as they tried to preserve a piece of Hilltop history,” Hilliard said Tuesday. “As always, we will come together as a community and recover and work with the developer to ensure Somersworth continues ‘On the Move.’”

The city’s building inspector has ordered what’s left of the building be razed. The value of the loss is not yet known, according to a news release issued by Hoyle.

Officials warn that because the building is an older mill structure there will be hidden pockets of fire unable to be extinguished until exposed by demolition equipment. People are asked to stay away from the site.