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Carbon monoxide

What is carbon monoxide?

Carbon monoxide (CO) is a colourless, odourless and toxic gas that is produced when fuels such as natural gas, propane, wood, tobacco and gasoline are burned incompletely. This can happen if there’s a lack of fresh air, or if dirt and debris collect in the burner.

Having your natural gas appliances regularly inspected and maintained by a licensed natural gas contractor can help prevent carbon monoxide in your home. Installing a CO alarm can also provide an extra measure of safety between regular maintenance visits. Learn more about maintaining your gas appliances and finding a licensed gas contractor.


 CO leaks & poisoning


Do you suspect carbon monoxide is present in your home?

  • Open all doors and windows.
  • Get fresh air immediately outside.
  • Seek medical attention if needed.
  • Turn off any appliances that you suspect are faulty.
  • Have a licensed gas contractor inspect your appliances.

Signs that carbon monoxide may be present include:

  • an unidentified chronic odour inside the building

What is carbon monoxide poisoning?

If carbon monoxide is inhaled, it depletes the amount of oxygen in your red blood cells, resulting in specific symptoms. Depending on the amount inhaled and the length of time you have been exposed, symptoms could include the following:

  • chronic headaches
  • nausea
  • drowsiness
  • impaired judgment
  • loss of coordination

Exposure to high amounts of carbon monoxide can lead to unconsciousness, brain damage and death.  If you suspect carbon monoxide poisoning take the following steps:

  • move the person to fresh air right away
  • call for medical assistance

The risk of carbon monoxide poisoning from natural gas appliances is extremely low. A very small percentage of carbon monoxide deaths are actually caused by natural gas appliances. Most are caused by fires and car exhaust.


Visit The Community Against Preventable Injuries for more information on the detection and prevention of CO poisoning.

The Community Against Preventable Injuries​ (Preventable) is a nation-wide, multi-partner organization designed to raise awareness, transform attitudes, and ultimately change behaviour.


 CO alarms


Carbon monoxide alarms are a source of warning that can provide extra protection between maintenance visits.  They are NOT a substitute for regular inspection and maintenance, nor are they a substitute for smoke alarms.

Buying tips

  • Buy an alarm certified to the latest Canadian Standards Association (CSA) requirements, displaying the CSA (blue flame) logo. Carbon monoxide alarms that comply with the latest requirements will be labelled CSA 6.19-01. 
  • Look for a battery operated unit or a 110-volt plug-in model with a battery backup in case the power fails. Note that the battery backup feature of 110-volt models may only operate for a few hours after the power fails.
  • Look for a model that clearly lists the replacement date and warranty period.
  • Peak-level display and hours-since-peak features can help you investigate CO problems — they show the highest level of carbon monoxide reached, as well as how long ago the reading occurred.

Installation tips

  • The best place to install carbon monoxide detectors is in the hallway outside your bedrooms (on each level if you have more than one floor).
  • Don't install a carbon monoxide alarm in or near an attached garage or carport or near the door leading into the house from the garage or carport.
  • Don't install a carbon monoxide alarm in your furnace room, kitchen or within 15 feet of any fuel-burning appliance.

 Appliance maintenance & CO


How to avoid problems with CO

While buying and installing a carbon monoxide alarm is an added safety measure, the best solution is regular appliance maintenance. You can easily reduce the risk of carbon monoxide poisoning by following some simple guidelines:

  • Always have a licensed gas contractor who is registered with Technical Safety BC, install, inspect and service your natural gas appliances and check vents regularly to make sure that they are not disconnected, blocked or corroded. Find a licensed contractor in your area using our Trade Ally Network directory.
  • Make sure your contractor uses a licensed gas fitter (ask to see the gas fitter license). Also ask if the gas fitter knows how to check heat exchangers—companies that only clean furnaces and ducting may not be qualified to do this kind of inspection. More tips for hiring a gas contractor.
  • ALWAYS keep furnace fan compartment doors and/or the filter access panel in place.
  • Check that outside air ducts are clear. Be sure to clean bug screens before every heating season.
  • Open the damper of your wood-burning fireplace. If you have an open wood-burning fireplace, open the damper and partially open a window or door at or below the level of the fireplace when the fireplace is in use; close the damper after each fire, but only after the ashes are cool.
  • Remove vehicles from the garage immediately after starting the engine.
  • Be sure that all vent hoods and pipes from fuel-burning equipment are in place and secure.
  • Ensure that an external vent is used for all gas appliances that are designed to be vented.
  • Never operate a barbecue, camp stove or lantern in an enclosed space.
  • Buy equipment that bears the seal of an approved certification agency such as the Canadian Gas Association or the Canadian Standards Association.
  • Keep the area around your furnace clear for proper air circulation.
  • Install a carbon monoxide alarm.​

Energy upgrades and CO problems

Energy conservation saves energy and money. As you caulk and weatherproof, smaller amounts of cold, fresh air enter the house and less heat loss occurs. But too much weatherproofing can be bad for indoor air quality and appliance and vent operation.

If you are planning to do a lot of caulking, draftproofing or insulating, or add a high-volume kitchen or bathroom exhaust fan, talk to a licensed gas or ventilation contractor first.​


 Find a contractor


Use the FortisBC Trade Ally Network directory to find a licensed gas contractor in your community. When selecting a contractor, make sure personnel are certified gas fitters and experienced at inspecting all types of gas appliances for safe operation. Get more tips for choosing a contractor.