The Ontario fire marshal has been called in after Hamilton firefighters were called to a multiple-alarm fire in the central part of the lower city early Monday.
It started about 3:30 a.m. on Cannon Street East, near Cathcart Street, and when the fire department arrived at the residence, flames could be seen coming from the second floor and roof.
No one was found inside the building during a search and rescue operation.
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The building appeared to be undergoing renovations and firefighters had to dodge a number of hazards inside, including holes in the floor.
One firefighter suffered a hand injury and was taken to hospital for treatment.
Damage is said to be extensive.
The cause of the blaze and the damage estimate have not been announced.