Careless smoking is the suspected cause of a one-alarm fire that sent a man in his 40s to hospital late Thursday morning.

Firefighters rescued the victim from a rooming house at 390 Bathurst St., between Dundas Street West and College Street, after the blaze was reported at about 11:50 a.m.

Toronto Fire Services says the man was breathing but unconscious when he was removed from the three-storey building and taken to Toronto Western Hospital.

The blaze, reported by a passerby who saw smoke pouring out of a window, was quickly extinguished.

Damage is estimated at $5,000.