Carbon Monoxide (CO) is a poisonous gas that is colorless, odorless, tasteless and non-irritating. When breathed into the body, CO combines with the blood and prevents it from absorbing oxygen. When this blood, deficient in oxygen, reaches the heart and brain, it can damage those organs and cause illness or death.

There are several physical symptoms of CO poisoning. These vary, depending on the amount of CO in the bloodstream; the higher the concentration, the greater the danger. Some signs of CO can include: unusually high indoor humidity with persistent heavy condensation on walls and windows; stuffy or stale indoor air; and soot or water collecting near a burner or vent.

Mild exposure:

  • Slight headache
  • Vomiting
  • Nausea
  • Fatigue
  • Blurred vision
  • Flu-like symptoms that disappear when the person breathes fresh air

Medium exposure:

  • Drowsiness
  • Confusion
  • Severe headache
  • Rapid heart rate

Severe exposure:

  • Convulsions
  • Unconsciousness
  • Cardiac/respiratory failure
  • Even death

Severity of the physical symptoms will vary depending on age, general health, level of physical activity, and duration and concentration of exposure.

Treat with fresh air or pure oxygen. Severe exposure requires medical attention.

Usually carbon monoxide is produced during burning of fuels such as gasoline, coal, wood, charcoal, kerosene, natural gas, propane and heating oil, and almost any other combustible material such as tobacco, fibers and paper. There is even more risk of CO accumulation if your home is tightly sealed and not properly ventilated.

While smoke inhalation from fires is a common cause of CO poisoning, cigarette smoke and vehicle exhaust are the most common sources of CO exposure. If your home has an attached or “tuck-under” garage, air and any pollutants in the air flow from the garage into your home. So, if you leave a car or other combustion engine running inside your garage, or if an air intake duct to your home is located next to a heavily traveled road or near a loading dock, CO can accumulate inside your home.

Any fuel-burning equipment or appliances, including wood stoves, fireplaces, space heaters, barbecue grills, furnaces, water heaters, boilers and ranges, have the potential to produce carbon monoxide.

When natural gas equipment is properly operated and maintained, it usually will not produce carbon monoxide.

Usually, CO forms when fuel-burning appliances and equipment are malfunctioning or improperly maintained.

Normally, when adequate combustion air is available and the appliance is properly installed and maintained, all gases and other products of combustion will be harmlessly vented to the outdoors.

Homes that are tightly built or have large exhaust systems, such as kitchen exhaust fans, need to have a system that will provide air to replace the that is pulled out of the home by the exhaust. Without adequate make-up air, air from the outside can be pulled down the furnace or fireplace chimney and cause carbon monoxide to form.

  1. Open windows to ventilate the area.
  2. Shut off your furnace and other fuel-burning appliances.
  3. If you’re experiencing physical symptoms, get everyone, including pets, out of your house.
  4. Call 911 immediately.
  5. If CO is discovered, don’t return to your home until the source has been found and the problem corrected.

No. CO has no smell. When you smell gas, you’re smelling an odorant OPU adds to natural gas for safety reasons. If you smell natural gas, leave your home immediately and call 911 from another location.

  • Never operate an automobile, lawn mower or any combustion engine, or barbecue grill or similar equipment in an enclosed area such as your home, garage, tent trailer or fish house, even with the door open.
  • Never leave a fire smoldering in your fireplace
  • Have fuel-burning equipment regularly checked by a qualified technical (most manufacturers recommend annual check-ups)
  • Check frequently for visible signs of problems, such as high indoor humidity, or soot or water collecting near a burner or vent
  • Equipment that uses natural gas should show a clear blue flame; a yellow or orange flame may indicate a problem and should be checked by a qualified technician
  • Provide adequate combustion air for all your appliances
  • Make sure your fresh air intake(s) is not blocked or restricted
  • Be sure all fuel-burning appliances and equipment are properly vented to the outdoors
  • Keep vents and chimneys clear of debris or other blockages
  • Don’t try to heat a room with your gas range, oven or clothes dryer
  • If you have an appliance converted from one type of fuel to another, have the conversion done by a qualified technician
  • A CO detection device with an audible alarm and a digital display, installed near bedrooms, can provide added protection