The old Sydney Mines fire hall was set on fire this week, making it the third suspicious fire in the past few weeks.
The former fire hall was empty when it caught fire around midnight Sunday. Doug MacKenzie, the deputy fire marshal for the area, called it a suspicious fire. He has passed the case to the police arson task force.
There have been a total of eight suspicious fires in the Cape Breton Regional Municipality in the last month.
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 last week, and a third abandoned building was burned down before then.