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Carbon Monoxide

Carbon monoxide (CO) is an odourless 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.

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

  • Open all doors and windows
  • Call a TSSA registered heating contractor for an inspection (there will be a charge for this inspection). Contractor registration can be verified by calling the TSSA at  1-877-682-TSSA (8772).

If you suspect CO in your home and there are medical symptoms:

  • Call 911

  • Ensure all people and pets leave the home
  • Seek medical attention immediately
  • Call Union Gas (1-877-969-0999) or a Technical Standards and Safety Authority (TSSA) registered heating contractor for an inspection (there will be a charge for this inspection). Contractor registration can be verified by calling the TSSA at  1-877-682-TSSA (8772).

Symptoms of carbon monoxide 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.

Signs you may have CO in your home

Keep your eyes open for the following signs of carbon monoxide in your home:

  • 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. 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 unusual gases in your home. Even though carbon monoxide is odourless, it is sometimes accompanied by odour-bearing exhaust gases.

If you detect these signs, turn off the equipment and contact a TSSA registered heating contractor.

Prevent CO 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 occur which may increase the risk of CO entering your home. You can easily reduce this risk by:

  • Have your fuel-burning equipment inspected annually by a Technical Standards and Safety Authority (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.
  • 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 if your alarms use them.
  • Check your chimney too!

    If your chimney is plugged, you could be breathing the exhaust from your 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, bird's 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.