The Fire Marshall has been called in to investigate last evening's(WEDNESDAY) massive blaze at Muskoka Timber Mills.
Firefighters remain on scene as pockets of fire continue to pop up at the Manitoba Street property.
Deputy Fire Chief Jared Cayley says the Fire Marshall is being brought in because the damage total will be significant, adding the site cannot be accessed until the fire is completely out.
Meanwhile, the investigation continues into the other large fire in the town on Wednesday, at an abandoned building at the former Bangor Lodge.
Firefighters were called to tackle that blaze as they were mopping up from a smaller fire at a workshop on Fraserburg Road.