Carbon monoxide (CO) is a highly poisonous gas, which is often called the 'silent killer' because it is odourless and colourless. CO is produced from the combustion of wood and other fuels such as gasoline (in vehicles), propane, and natural gas. You can't see or smell CO, so it's extremely important to detect it in order to keep your family safe.

What you need to know

  • If CO goes undetected, exposure to high levels can cause brain damage or even death.
  • CO can build up when any fuel-burning equipment, such as your furnace, water heater or fireplace, doesn't burn or vent properly or has a blocked vent or chimney.

Know the signs and symptoms of CO poisoning

If CO 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 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

Three ways to protect your home:

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Inspection and maintenance

  • Get an annual inspection of all your fuel-burning appliances by a TSSA-registered contractor.
  • Never use outdoor fuel-burning equipment (generators, patio heaters, barbecues) inside your home or garage as a temporary heat source.

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Install a carbon monoxide alarm

It’s the law! If your home has a fuel-burning appliance, fireplace, or attached garage, you are legally required to install a CO alarm near all sleeping areas. For added protection, install a CO alarm on each level of your home.

But that’s not all...

  • Test your alarms monthly.
  • Change batteries twice a year.
  • Check the expiration date on the back of the alarm.

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Clear outdoor vents

Check that the vents from all natural gas appliances are unobstructed; clear appliance intake and exhaust vents after every snowfall; conduct yearly checkups to ensure that your chimney and other gas appliance vents are not blocked, remain in good condition, and function properly.


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Natural gas and carbon monoxide are different

Natural gas and carbon monoxide are not the same gas. Carbon monoxide detectors will not detect natural gas leaks. Natural gas contains an odourant that makes it smell like rotten eggs, even in very small concentrations. If you smell rotten eggs, there could be a leak in your gas piping. Open all doors and windows, do not use electrical equipment, extinguish all open flames/heat sources, and leave the building. Call Enbridge Gas immediately at 1-866-763-5427.

Act fast! If your CO alarm sounds and there are no medical symptoms:

  • Open all doors and windows.
  • Call a Technical Standards and Safety Authority (TSSA) registered heating contractor for an inspection (there will be a charge for this inspection).

If you suspect CO in your home and you or someone else is experiencing medical symptoms:

  • Ensure all people and pets leave the home.
  • Call 911 from a safe distance away from the home.
  • Seek medical attention immediately.
  • Call a TSSA registered heating contractor for an inspection (there will be a charge for this inspection).