As heavy smoke and fire filled a single unit on the third floor of 136 Albert St. in London, Ont., fire crews advanced search and rescue control.
"A number of residents had to be evacuated as well as remain protected in place within their unit until it was safe to evacuate themselves," says Platoon Chief Gary Mosburger of the London Fire Department.
Crews were able to put out the fire, and get all the residents out safely.
One person had to be assessed by paramedics on scene and taken to hospital.
"The fire is deemed suspicious, but we will be working with our Fire Prevention Investigator and London Police Service (LPS) Special Crimes Unit to determine next steps," says Mosburger.
"We have called in Fire Prevention Investigator to determine origin, cause and circumstances of this fire and we'll have further information on damage estimation when it comes available."
Witnesses tell CTV London they saw one person placed under arrest and taken into custody but police would not confirm.
Two London Transit Commission (LTC) buses are also on scene to keep evacuees warm. Personal protective equipment has also been provided to them.
"We are working with our partners LPS and LTC to house residents that have evacuated," adds Mosburger.
"We are taking COVID protocols with masking for those people to ensure we have a warm place to stay until we can determine cause of fire and get them back to their units."
Mosburger says they are working to ensure it is safe for residents to reoccupy before they can return to the building.
"We'll be checking air quality before we do reoccupy. The building has been compromised from a fire safety perspective, so we have to make sure it’s under a fire watch during the time of re-occupancy, and it will remain that way until the building is fully online."