Assistant fire chief Lou Wilde says the barbecue was being used when the blaze started, but it's not known if it was faulty or whether human error was involved.
He says the fire climbed the outside of the four-storey building, got in the attic and torched the roof of the 64-unit building.
Wilde says most of the damage occurred on the fourth floor, but the hallways and walls on the second and third floors were relatively spared.
Most of the 100 residents required emergency services after the blaze, which was reported at about 4 p.m. Tuesday and was battled into the evening by about 70 firefighters.
Fire chief Jeff Carlisle says up to two cats are unaccounted for but no one was hurt. (CKFR)
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