Firefighters took more than eight hours to extinguish a fire at a century-old mill in Pawtucket, R.I., that sent flames leaping through the roof and caused walls to collapse.

The fire started at about 11:30 p.m. Wednesday at the former Union Wadding Mill. The 10-acre building is more than 150 years old.

The mill was mostly unoccupied, but several apartments were evacuated as a precaution. No injuries were reported.

Officials say it appears the fire started on the first floor in a part of the building without power. They say it's too soon to know whether the cause is accidental or a case of arson.