What Is Carbon Monoxide Poisoning?

Carbon monoxide (CO) is a poisonous gas that is odorless, colorless and tasteless. It is formed from the incomplete combustion of fuels, such as heating oil, wood, gasoline, coal, natural gas, propane or charcoal. When heating units or motors are not working properly, or if their exhaust fumes are not vented outdoors, carbon monoxide can build up inside your home or building.

Breathing small amounts of CO can result in headaches, dizziness or nausea. Prolonged exposure could lead to fainting or, in some cases, could be fatal. If you suspect someone has been exposed to carbon monoxide, get the person into fresh air and seek immediate medical attention.

Signs of CO Build-Up

• Stuffy, stale or smelly air with high indoor humidity.
• Fallen soot from a fireplace chimney or furnace flue.
• No draft in the chimney or flue.
• Hot draft backing out of the flue diverter when the furnace is operating.

Some Precautions

• Annually inspect your fireplace chimney and furnace venting system and keep them clear of leaves, nests, soot or other obstructions.
• Make sure the flue pipe connection to the furnace chimney is tight and the pipes aren't dented or cracked.
• When switching from oil to natural gas, be sure to have the chimney cleaned and inspected by a qualified service person.
• Check that the vent pipe on your water heater is as tight and well-fitted as the furnace piping. Replace worn parts or ill-fitting pipes.
• Have a qualified heating contractor tune up and maintain your heating system periodically.
• Never leave a vehicle or gasoline-powered equipment running in a garage, even with the garage door open.
• For the same reason, don't use grills indoors or in an enclosed space.

Install a CO Alarm

Install a carbon monoxide alarm in your home. Most manufacturers recommend installing one near the sleeping area because we're most vulnerable to CO poisoning during sleeping hours.

Read more about carbon monoxide poisoning and CO alarms at Underwriters Laboratories, Inc.