Carbon monoxide safety
Find information and tips about how to protect yourself and your loved ones from carbon monoxide.
On this page Skip this page navigation
Carbon monoxide (CO) is known as the silent killer because it is an invisible, tasteless and odourless gas that can be deadly. Over 65% of CO-related injuries and deaths in Ontario occur in the home.
CO is produced when fuels — such as propane, gasoline, natural gas, heating oil or wood — do not burn completely in fuel-burning appliances and devices, such as:
- hot water heaters
- portable heaters
Exposure to CO can cause:
- loss of consciousness
If your CO alarm sounds, you or other occupants may experience symptoms of CO poisoning. It is critical to get everyone out of the home immediately and call 9-1-1 or your local emergency services number from outside the building.
Prevent carbon monoxide build-up in your home
The following tips can help prevent carbon monoxide build-up in your home:
- Ensure fuel-burning appliances, chimneys and vents are cleaned and inspected by professionals every year before cold weather sets in. Find a registered contractor near you.
- Ensure outside vents and chimneys for the dryer, furnace, stove, fireplace and other fuel-burning appliances are always clear of snow and debris.
- Only use gas and charcoal barbeques outside, away from all doors, windows, vents and other building openings. Never use barbeques inside garages, even if the garage door is open.
- Only use portable fuel-burning generators outdoors in well-ventilated areas away from windows, doors, vents and other building openings.
- Ensure all portable fuel-burning heaters are vented properly, according to the manufacturer’s instructions.
- Never use a stove or oven to heat your home.
- Open the flue before using a fireplace for adequate ventilation.
- Never run a vehicle, fueled engine or motor inside a garage, even if the garage door is open. Always remove a vehicle from inside the garage immediately after starting it.
Install carbon monoxide alarms
Install a carbon monoxide alarm adjacent to each sleeping area if your home has either:
- a fuel-burning appliance
- a fireplace
- an attached garage
Adjacent to each sleeping area means the hallway or area outside the sleeping area. For instance, a CO alarm must be installed in the hallway nearest multiple bedrooms in a house or apartment.
For added protection, install a carbon monoxide alarm on every storey of your home according to the manufacturer’s instructions.
Fuel-burning appliances include:
- hot water heaters
- gas or wood fireplaces
- portable fuel-burning heaters and generators
- test CO alarms every month by pressing the test button
- replace batteries every year
- replace CO alarms according to the manufacturer's instructions
If you live in an apartment or condo building and:
- have a fuel-burning appliance, install a carbon monoxide alarm outside each sleeping area
- the building has a service room, carbon monoxide alarms must be installed in the service room and adjacent to each sleeping area of all condos/apartments above, below and beside the service room
- the building has a garage, carbon monoxide alarms must be installed adjacent to each sleeping area of all condos/apartments above, below and beside the garage
Landlords are responsible for:
- installing and maintaining CO alarms in their rental units
- testing CO alarms in rental units annually, when the battery is replaced, when changes are made to the electric circuit, or a change of tenancy occurs.
It is against the law for tenants to remove the batteries or tamper with CO alarms in any way.
CO alarm sounds
Your CO alarm sounds different than your smoke alarm. Test both alarms monthly and make sure everyone in your home knows the difference between the two alarm sounds.
If your CO alarm sounds, you or other occupants may experience symptoms of CO poisoning. It is critical to get everyone out of the home immediately and call
If your CO alarm sounds and no one is suffering from symptoms of CO poisoning, check to see if the battery needs replacing or the alarm has reached its "end-of-life" before calling