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Ministère de la Sécurité publique

Carbon Monoxide

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What is carbon monoxide (CO)?

Carbon monoxide is produced when a vehicle or appliance burns fuel such as gasoline, oil, natural gas, kerosene, propane and wood.

Carbon monoxide is odourless, colourless, flavourless and does not cause irritations. It is impossible for someone to detect its presence.

Carbon monoxide is responsible for hundreds of intoxications each year in Quebec, from which about fifteen are deadly.

Carbon monoxide is present in most households.

Only a CO detector can detect the presence of carbon monoxide. A smoke detector does not protect against carbon monoxide.

Identifying CO sources

  • Running vehicles with a combustion engine (automobiles, snowmobiles and all-terrain vehicules) in underground garages or next to the house, or in closed areas;
  • Oil furnaces, wood stoves and gas heating appliances;
  • Heating appliances using fuel, such as natural gas, kerosene, oil and wood;
  • Appliances using propane or gas, like a range, a refrigerator, a dryer and a barbecue;
  • Tools with a combustion engine, such as lawnmowers, snow blowers, saws and buffing machines.

Identifying the symptoms of a CO intoxication

Intoxications occur when an appliance or a vehicle does not operate properly or when it is used in a closed or poorly ventilated area. Babies, young children, pregnant women, elderly persons and people suffering from respiratory or cardiac diseases are more vulnerable to the effects of carbon monoxide.

Symptoms vary depending on the intensity of intoxication from the simple headache if poisoning is mild to unconsciousness if it is serious.

The symptoms

  • Low exposure: frontal headache, nausea and fatigue;
  • Moderate exposure: persistent frontal headache with a pulsing sensation, nausea, vertigo or dizziness, sleepiness, vomiting, rapid pulse, impaired reflexes and judgment;
  • Very high exposure: weakness, faintness, convulsions, coma and death.

Often, the symptoms of a CO intoxication resemble those of food indigestion.

Preventing intoxications

Through the rigorous maintenance of heating appliances:

  • Make sure that your heating system is in good condition; have it inspected by a professional contractor at least once a year or when the system is modified or replaced;
  • When modifying the heating system, make sure that the internal dimensions of the chimney and smoke pipe are compatible with the new heating system;
  • Have your chimney swept at least once a year;
  • Make sure that there are no obstructions in the chimney, like a bird nest, debris or snow;
  • When renovating the house, make sure that modifications, such as better windows, a more powerful kitchen hood, better insulation and air exchange system will not reduce the quantity of the fresh air needed to ensure the proper operation of the heating appliance;
  • If you have a second home, verify all appliances that use fuel during your first visit after winter.

Through the adequate use of combustion appliances:

  • Never leave a car engine running inside the garage, even with the door open;
  • Never use the remote starter when the car is in the garage. Do not leave the remote starter of your vehicle in the reach of children, to avoid the accidental start-up of the vehicle;
  • Never use a gas oven instead of the main heating system, even for a short period of time;
  • Never use a propane barbecue or a heater using fuel inside the house, apartment, cottage/cabin, trailer or any other type of building;
  • Never block the air vents and exhaust systems of appliances that operate with fuel;
  • Never use a flame-producing appliance in a closed area, like a lamp or a stove;
  • Never operate a motor tool, like a chain saw or a generator, in a garage or a closed or poorly ventilated garden shed.

Through safe behavior during power outage:

  • Use only lighting, heating and cooking appliances designed for indoor use.
  • If you use a generator, install it outside and follow the manufacturer's instructions.

Choosing your CO detectors

Choose them by verifying:

  • the presence of a seal from a recognized certification agency, such as CSA and ULC;
  • the type of power supply;

    • battery-operated
    • electric
      • appliance that you can plug-in a power outlet, or
      • permanent appliance installed by a professional electrician

    • combined (battery and electricity)

  • the type of alarm: visual, audible or combined (visual and audible);
  • the presence of a test button to verify the proper operation of the device;
  • the presence of a low battery alarm;
  • the presence of a CO concentration display;
  • the existence of combined models;
    • CO and smoke detectors
    • CO and propane detectors
    • CO and natural gas detectors

Installing your CO detectors

Install them by following the instructions of the manufacturer:

  • On each floor of the house;
  • In the corridor, near the bedrooms;
  • Near the garage door next to the house;
  • In the room above the garage next to the house;
  • At any height on the wall, since carbon monoxide spreads equally in the air. However, choose an area that is easy to monitor and out of the reach of children and animals;
  • The combined CO and smoke models can be installed like smoke detectors.


  • Rooms that are too hot (over 37.8 °C) or too cold (less than 4.4 °C);
  • The kitchen and areas less than two metres from cooking and combustion appliances;
  • Damp rooms, like bathrooms, or rooms less than six metres from a source of moisture;
  • Areas close to air inlets and outlets, such as a ventilation system and drafts;
  • Rooms that are not ventilated, where chemicals are stored;
  • The inside of a garage;
  • The dead space of a cathedral ceiling;
  • Power outlets activated by a switch on the wall.

Maintaining your CO detectors

  • Test the alarm of your device by pressing the test button until you hear the alarm. The response time can take up to 20 seconds.
  • Never try to test your CO detector by exposing it to the exhaust pipe of a vehicle. This would immediately damage your device and void the warranty;
  • Clean the outside of the detector once a month with a vacuum, using a soft brush. Avoid using water, household cleaning products or solvents that are incompatible with the components of the device.

Change the battery every year or use, if possible, a lithium battery.

Knowing what to do if a person shows signs of intoxication or if the CO detector issues a signal:

  • Quickly evacuate the premises.
  • Dial 9-1-1.
  • Do not return inside the contaminated area; wait for the authorization of an expert who will confirm that there are no intoxication risks.

Dernière mise à jour : 20 août 2014