Crews were still battling the blaze at 4:30 p.m. in the parts of the factory that remained standing after the fire first broke out Sunday morning.
The St. Albert's cheese factory, known for its distinctive cheese curds, was established in 1894 in St. Albert, Ont., about a 45-minute drive southeast of Ottawa.
It is one of the oldest Francophone co-operatives in Ontario, and employed about 110 people in the small community.
Smoke visible for 15 km
Workers said the fire alarm went off Sunday morning before 9:30 a.m. The building was evacuated and workers said it wasn't long before the fire spread quickly though one of the factory's older buildings.
At its height, fire from the factory was visible from a kilometre away, and smoke was visible from 15 kilometres away.
Fire crews from nine local fire departments have been battling the blaze since 9:30 a.m.
The older of two buildings was gutted. Crews used an excavator to collapse it in order to curb the spread of the fire to the other part of the factory.
But the fire was still burning into Sunday afternoon, and most people on site fear much of the factory will be a writeoff.
There are no reported injuries, according to the Ontario Provincial Police. The cause of the fire is now under investigation.
Roads closed, people moved from homes
People were being advised to stay clear of the area because of concerns about ammonia and other chemicals in the plant.
Local fire departments have closed all roads in and out of St. Albert as they contain the fire.
Police on the scene had told Radio-Canada the area around the factory would be evacuated, but a spokesperson for the OPP said no evacuation has been confirmed.
Many residents near the factory have left on their own as a precaution, the CBC's Ashley Burke reports.
Francois St-Amour, the mayor of The Nation township that includes St. Albert, said residents who have left their home are being housed in a local community centre.
St-Amour said he would be meeting with them Sunday night.
Ministry of Natural Resources investigators are on site monitoring the air quality but say there is no immediate threat to the population.
Ontario Provincial Police had briefly closed Highway 417 westbound and off ramps to the Casselman and St. Albert area because of the spread of fire.
Backbone of town, residents say
Many of the people watching the fire were in tears as they watched the fire spread on Sunday afternoon, according to the CBC's Ashley Burke.
"It's the backbone of the town, so we'll have to see what's happening in the future," said Andre Lavergne, whose grandfather was one of the founders of the co-op.
Rejean Ouimet, the co-operative's general manager, told CBC that there are plans in the works to rebuild the factory.