The incident occurred at the Paletta International Corporation building, a meat processing plant founded in 1967 located near the busy intersection of Appleby and Mainway.
The blaze broke out at 4480 Paletta Court just after 4:10 p.m. Wednesday and continued to burn for hours, eventually consuming at least a third of the facility.
Lazenby said all occupants of the building evacuated safely with a lot of them out of the building by the time emergency services personnel arrived. "We are also pleased that everyone in the building is accounted for".
"The Ontario Fire Marshal's Office will be attending tomorrow to proceed with the investigation, but I think it will be quite some time before we're able to establish what happened".
Because of the size of the fire, crews want to make sure there are no flare- ups from fallen debris, he said. Hamilton and Oakville fire departments have been called in for extra help, according toe Burlington Fire.
A cause of the blaze has not yet been determined but Lazenby says it started on the east side of the building.