Mississauga Fire and Emergency Services is urging people who live in condos and apartments to make sure their homes meet Ontario's updated carbon monoxide alarm rules.

Amendments to the Ontario Fire Code that took effect on Jan. 1, 2026, require carbon monoxide (CO) alarms on every floor of homes that have fuel-burning appliances, fireplaces or attached garages. The province has also added requirements aimed specifically at people living in multi-unit buildings.

Which units need an alarm

According to the fire service, a condo or apartment unit must have a CO alarm if any of the following applies:

  • The unit has a fuel-burning appliance, such as a gas stove or range, or a fireplace

  • The unit is directly above, below or beside the building's service room

  • The unit is directly above, below or beside the building's garage

  • The unit is heated by air from a fuel-burning appliance outside the unit, such as a furnace in a service room

Alarms must be placed next to each sleeping area, which usually means the hallway outside the bedrooms, and on every storey of the unit, including lofts and upper floors without bedrooms. Public corridors also need alarms if they are heated by air from a fuel-burning appliance.

Who is responsible

The owner or landlord is responsible for installing and replacing required alarms. Tenants can be fined for disabling an alarm or for failing to tell the owner when one is not working. Penalties for not complying start at $235 and, on conviction, can reach $50,000 for individuals. The rules apply to every type of home, from condos and townhouses to detached houses, cottages, rentals, care occupancies and retirement homes.

Why it matters

Carbon monoxide has no colour, taste or smell, and poisoning can be fatal for both people and pets. In an apartment building, a single faulty furnace can put many households at risk, which is why the fire service says alarms in each unit add an important layer of protection.

Early symptoms are often mistaken for the flu. They include headache, dizziness, confusion, weakness, chest pain, and an upset stomach or vomiting. Anyone who suspects exposure, or whose CO alarm sounds, should get to fresh air right away and call 911.

Keeping alarms working

The fire service recommends testing CO alarms monthly, replacing them every 10 years or as the manufacturer directs, and having fuel-burning appliances and vents inspected every year. Alarms should not be blocked by furniture or curtains. When buying a new alarm, look for a Canadian certification mark; combination smoke and CO alarms are also available.

Residents with questions about the new requirements can call the fire service's Fire Prevention and Risk Reduction Division at 905-456-5700, a non-emergency line.