Carbon Monoxide

What you need to know

Carbon monoxide (CO) is an odourless, colourless, tasteless and invisible gas that occurs through combustion, or the process of burning.

Excessive amounts of CO will form when there isn’t proper ventilation or an adequate air supply. Most often, exposure to carbon monoxide occurs indoors. Any appliance that burns fuel can cause CO build-up, including fireplaces, gas stoves, water heaters, furnaces, grills, generators or car engines.

CO poisoning can happen to anyone but some people are more susceptible than others. Elderly, infants and those with heart or respiratory problems are more likely to experience effects of CO poisoning.

Physical Symptoms of Carbon Monoxide Poisoning

Low exposure to CO can be mistaken for symptoms of the flu, such as:

  • Nausea
  • Dizziness
  • Difficulty Breathing
  • Stomach Pain
  • Fatigue
  • Disorientation

High exposure to CO can become lethal when you begin to experience:

  • Memory loss
  • Loss of consciousness
  • Loss of vision
  • Chest pains
  • A feeling of vertigo
  • Seizures
Signs of Carbon Monoxide
  • Stuffy air
  • Sudden formation of excessive moisture on windows and walls
  • Soot build-up around appliances and vents
  • A yellow flame in a natural gas appliance instead of blue
  • Fumes that smell like vehicle exhaust
  • Poor upward draft from your fireplace or wood-burning stove
  • Odd odour, strange sounds or gas burning appliances that are running less efficiently
Common sources of Carbon Monoxide
  • Using barbecues or camping stoves indoors
  • Car engines, generators, power tools and lawn mowers turned on and running indoors
  • An idling vehicle in an attached garage
  • Attached garage passageway door to your home is ajar
  • Heated garages or shops with no or improper ventilation 
  • Corroded, disconnected or plugged chimneys on fuel-burning appliances
  • Defective furnace heat exchanger
  • Depressurization (ie. when your home's inside air pressure exhausts faster than outside air can come in)

A CO alarm alerts you to danger before physical symptoms of CO poisoning appear. 

Install an alarm on every floor of your home and near maintenance rooms, cooking areas and bedrooms. If you have an attached garage it is important to put one near the door going into the house. Avoid areas of high humidity such as bathrooms.

Most alarms last 5-7 years but the manufacturing label will show the expiry date. Make sure your alarm is working by using the test button monthly and replacing the batteries annually. 

What to do if the CO Alarm Goes Off

Remain calm.
If you are experiencing symptoms, take the following steps:

  • Leave the home or building and go outside
  • Call 911 (or your local fire department) and let them know you have symptoms of CO poisoning
  • Do not enter the home or building until the CO level check is complete or responders say it is safe
  • Identify the source and correct the issue

If you are not experiencing any symptoms:

  • Open doors and windows to create ventilation
  • Turn off any gas appliances 
  • If your alarm stops, you may have low levels 
  • Contact a licensed heating contractor to check your appliances as soon as possible

If responders can not find the source of the CO, you may have a false alarm. To ensure CO monitoring continues:

  • Replace the batteries in the alarm and complete any tests as per the manufacturer's direction
  • Replace the entire unit if it exceeds the expiration date or you feel it’s malfunctioning
  • Ensure the alarm is at least 10 feet away from areas of high humidity
More Tips to Keep you Safe
  • Make sure a licensed heating contractor installs your gas equipment or appliances and inspects them annually
  • Keep the area around gas equipment and exterior vents clear
  • Never leave your vehicle idling in the garage. Start lawn mowers and snow blowers outside
  • Don’t operate an unvented appliance like a barbecue or portable propane heater in an enclosed space like a garage
  • Never operate a generator in a house or garage