Carbon Monoxide

Carbon monoxide (CO) is an odourless, toxic gas that can be produced from a number of sources such as exhaust from a car or woodstove, or natural gas-fired equipment that is not functioning properly or appropriately ventilated. You can't see it, smell it, or taste it; but carbon monoxide can cause serious harm.

When properly installed, maintained and vented, any CO produced by appliances will be vented outside the home.

Install a carbon monoxide alarm

Landlord and Tenant Responsibilities

The landlord of the building is responsible to install, maintain and test CO alarms. Tenants may not disable their CO alarms. Learn more from Ontario’s Carbon Monoxide Alarm Q&A's.

Unsafe levels of CO can be detected by carbon monoxide alarms, which are constructed to detect airborne concentration levels of CO in parts per million (ppm) and sound an audible alarm when harmful levels are present.

Ontario Fire Code requires all homes (whether single family, semi, or other) with fuel burning appliances (including fireplaces) and/or attached garages, to be equipped with CO alarms. These alarms should be located outside of all sleeping areas.

Do you live in a condo or apartment building? If it has a service room, CO alarms must be installed in the service room and adjacent to each sleeping area above, below and beside the service room. If it has a garage, CO alarms must be installed adjacent to each sleeping area of all units above, below and beside the garage. 

The only residences not affected by the regulation are those that are all electric and have no attached garages or fireplaces. But if there is outside equipment, such as large generators or machinery, that vents outside your windows or doors, you may also wish to consider installing a CO alarm in your home to further protect your safety.

Read more about CO alarm installation from Ontario's Carbon Monoxide Alarm Questions and Answers.

If your carbon monoxide alarm sounds

  • Ensure all people and pets leave the home
  • Call 911

  • Seek medical attention immediately
  • Once everyone is safe, call Utilities Kingston at 613-546-1181; or
  • Call a heating contractor registered with the Technical Standards and Safety Authority (TSSA) for an inspection (there will be a charge for this inspection). Find a registered contractor by calling the TSSA at1-877-682-TSSA (8772), or by visiting TSSA’s Find a Contractor page.

Symptoms of carbon monoxide poisoning

If CO is inhaled, it depletes the amount of oxygen in the red blood cells, resulting in specific symptoms. Depending on the amount inhaled and the length of exposure, symptoms may include the following:

  • Low concentration: slight headache and/or shortage of breath during moderate physical activity.
  • Higher concentration: severe headache, dizziness, nausea, vomiting, mental confusion, weakness, vision and hearing impairment, collapse or fainting during exertion, loss of muscle control and/or drowsiness.
  • Extreme concentration: unconsciousness, brain damage or death.

Signs you may have carbon monoxide present in your home:

Other than the audible alarm of your CO alarm, there are other signs

  • Stuffy, stale or smelly air (e.g., the smell of something over-heating or burning).
  • Dripping water condensation on your windows. (This is a reliable sign if you’ve already taken steps to reduce moisture production in your home. It could also mean your humidifier is set too high.)
  • Backdraft or soot from a fireplace, chimney or other fuel burning equipment.
  • A yellow burner flame, instead of the normal clear blue flame. This does not apply to natural gas fireplaces in which the yellow flame is intentional for a pleasing appearance.
  • A pilot light that keeps going out or the smell of gases in your home. Even though carbon monoxide is odourless, it is sometimes accompanied by odour-bearing exhaust gases.

If you detect these signs, consider whether you need to call 911 and obtaining medical assistance. At minimum, turn off the equipment and contact a TSSA-registered heating contractor.

Prevent carbon monoxide in your home

Natural gas has a safety record that’s second to none and there are strict codes that govern the installation and operation of natural gas equipment and appliances. While well-maintained equipment can operate safely for many years, wear and malfunctions can increase the risk of CO entering your home. You can reduce this risk by:

  • Have your fuel-burning equipment inspected annually by a TSSA-registered heating contractor to identify and fix any potential problems that could prevent your equipment from operating safely. Have the contractor check your natural gas fireplace during the same service call.

    Find a registered contractor by calling the TSSA at 1-877-682-TSSA (8772), or by visiting TSSA’s Find a Contractor.

  • Ensure your outdoor exhaust outlets for furnaces, fireplaces, water heaters, and clothes dryers are clear of ice, snow, birds’ nests, or other potential obstructions, so that carbon monoxide emitted by these appliances does not spill and build up in your home or business.
  • Install CO alarms on every level of your home to warn you of the presence of CO and regularly check the batteries.
  • Never put a portable generator indoors, and when using it outdoors make sure it’s well away from your home’s windows or doors (and your neighbours’) because of poisonous carbon monoxide gas.
  • Check your chimney too. If your chimney is plugged, you could breathe the exhaust from a furnace, fireplace, or woodstove. Stay healthy by checking your chimney in the following manner:
    • Examine the exterior brickwork from top to bottom. Make sure that there are no chalky deposits, moisture stains, cracks, or loose mortar.
    • Empty the clean-out pit at the base of your chimney. Check its contents for mortar, brick, birds’ nests, dead birds or stones. (The clean-out pit is located either inside or outside the house. Look for a metal frame with a door (if masonry chimney), or a “Y” or “T” fitting with a clean out cap installed at the chimney connection for the furnace vent (if manufactured metal chimney). The clean-out door and the cap should be kept closed at all times.)
    • Check for chimney obstructions by positioning a mirror in the clean-out pit, and moving it to find the angle that will allow you to see daylight clearly. (If you have an offset chimney, call a chimney specialist. If your appliances use a metal vent, the exterior portion of vent above the roof should be properly maintained. A coat of latex paint will protect it from weather and rusting.)

If you see any evidence of a deteriorating chimney, contact a qualified chimney contractor for assistance.