The 12th suspicious fire in the past month has been reported in the Cape Breton Regional Municipality.

An overnight fire heavily damaged a three-unit apartment building at 485 Townsend Street in Sydney.

The rear of the building was heavily damaged by fire and the roof is clearly destroyed.

Paul Ferguson is a platoon chief with the Cape Breton Regional Fire Service and says the building may have to be demolished.

Ferguson says the call came in at 1:54 a.m. Thursday and when crews arrived the building was fully engulfed.

"This fire was a serious fire," he says. "Crews entered the structure and found significant fire. They extinguished the fire and conducted a primary search. Eventually they realized the fire was beyond their control and we had to pull the crews out of the building."

Although the building was vacant, Ferguson says his members had to search the building to make certain and that puts the firefighters at risk.

Crews were on scene for several hours

A family living next door had to leave their house and Ferguson says crews were on scene for several hours.

The old Sydney Mines fire hall was set on fire last week. It was empty when it caught fire around midnight Sunday.

Doug MacKenzie, the deputy fire marshal for the area, called it a suspicious fire and passed the case to the police arson task force.

At the time, John MacPherson, the deputy fire chief in Sydney Mines, said the deliberately set fires put firefighters at risk and waste time and money.

A vacant house was set alight two weeks ago, and a third abandoned building was burned down before then.