A fire under a floor Thursday in an apartment building on Main Street that displaced 10 people appears have been caused by an electrical problem, according to Pittsfield Fire Chief Bernard Williams.

Williams said Thursday night that firefighters got a call around 2:40 p.m. Thursday that there was a structure fire at 671 Main St. and when they arrived, a lot of smoke was coming from the building, which has three apartments.

The fire, he said, was under the floor — in the crawl space — of an addition to the one-and-a-half-story, older building.

“We got there and we pulled the skirting off,” Williams said.

The fire was under a floor of an entryway that led to two apartments, according to Williams.

“We took a piece of the floor out to get at what was going on, and we had to remove a portion of the sill because it was made up of several pieces,” he said.

He said the cause of the fire appears to be electrical in nature. Central Maine Power Co. was called to shut the power off, he said.

“We had to shut the power off because there was a lot of damage to surrounding wires,” he said.

There was some fire damage under the flooring but no smoke damage to the building, and the tenants were staying elsewhere because there is no power, according to Williams. More than a dozen firefighters from Pittsfield and Burnham fire departments worked at the scene. The Newport Fire Department was called but then directed to return to the station, as it was not needed.

The state fire marshal’s office was not called to the scene, according to Williams.

“I’m satisfied with what we found as a cause because it looks to be the point of origin,” Williams said. “It started in the sill under that doorway.”

He said the sill moved, and when people walked on the entryway, it chafed against a wire. and he believes that is what caused the fire. Firefighters left the scene around 3:45 p.m., he said.

Meanwhile, the American Red Cross sent out a news release Thursday night saying it was working with the three families affected to ensure they have food, a safe place to sleep and other essentials after the fire. The Red Cross will stay in contact with the 10 people over the next several days, the release says.

Williams said firefighters also responded to a fire at 10 a.m. Wednesday at Kleinschmidt Associates at 139 Main St.

The call was reported as a structure fire with smoke coming out of the roof, but it turned out to be a furnace malfunction that caused the cellar to fill with smoke and the smoke was actually blowing out of the chimney, according to Williams. He said there was actually no fire.

He said Kleinschmidt, an engineering consulting firm, has two buildings — at 139 and 141 Main St — and the building affected is at 139.

Amy Calder — 861-9247

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Twitter: @AmyCalder17