Carbon Monoxide Alarms

The Dangers of Carbon Monoxide

Source: First Alert®, BRK Brands, National Fire Protection Association

Carbon Monoxide (CO) is a colorless, odorless deadly gas. It's a common by-product of incomplete combustion, produced when oil, gas or coal burns. Sources in the home are:

  • gas and oil furnaces
  • refrigerators
  • clothes dryers
  • water heaters
  • fireplaces
  • charcoal grills
  • space heaters
  • automobile fumes that enter a home through walls or doorways (if a car is left running in an attached garage)

If a home is vented properly and is free from appliance malfunctions, air pressure fluctuations or airway blockages, the carbon monoxide will most likely be safely vented to the outside. Since you can not see, taste or smell it, carbon monoxide can kill you before you know it's there. Exposure to low levels over time can make you sick. Individuals with greater oxygen requirements such as unborn babies, infants, children or people with respiratory or coronary problems are at a greater risk for carbon monoxide poisoning.

Symptoms of Poisoning

Symptoms include headaches, fatigue, nausea, dizzy spells, confusion and irritability. Since symptoms are similar to the flu, CO poisoning can be misdiagnosed. As levels of COHb (a toxic compound in the blood caused by CO bonding with hemoglobin) rise, victims suffer vomiting, loss of consciousness, and eventually brain damage or death.

If you suspect you are experiencing symptoms of CO poisoning, please call 911.


The Consumer Product Safety Commission recommends installing at least one carbon monoxide detector per household, near the sleeping area in a home. Choose an Underwriters Laboratories (UL) listed detector that sounds an audible alarm. A carbon monoxide detector triggers an alarm based on exposure to CO over time. It is designed to sound an alarm before an average, healthy adult would experience symptoms.

Installing a Detector

If you only have one detector, install it in the hallway near the sleeping area. Make sure you can hear it from every bedroom so it will awaken everyone if the alarm sounds while you're sleeping. Carbon Monoxide weighs the same as air and distributes evenly throughout a room. A CO detector will be effective if it's on a ceiling, near the baseboard or anywhere in between. Pick a location where the alarm will stay clean and out of children's reach.

Do not install next to a combustion appliance such as a gas or oil furnace, oven or water heater. Install the detector at least 15 to 20 feet away from these types of appliances.

Do not install where it will be exposed to strong chemical solvents, cleaners or in areas of high humidity. CO detectors work best when clean and dry.

Never spray cleaning chemicals on or near the detector. Keep it free of grease, soot and debris by vacuuming it gently. Test the CO alarm regularly by following the manufacturer's instructions.

When the Alarm Sounds

It is possible that a person would not be experiencing symptoms of CO poisoning when an alarm sounds. That doesn't mean there is not carbon monoxide present. The alarm is supposed to go off before you feel sick, so that you have time to react and take action.

Don't panic. Press the Test/Silence button to temporarily quiet the alarm, then call 911. Immediately remove everyone to a source of fresh air. Leave the CO alarm where it is. Do not re-enter your home until the emergency responders have arrived, your home is aired out and your CO detector returns to normal operation.

Have the problem corrected as soon as possible. Keep your home well ventilated until the problem has been fixed.

Safety Tips

Carbon Monoxide detectors are not substitutes for smoke detectors. Smoke detectors react to fire by-products, before CO detectors would alarm. Smoke detectors give an earlier warning of a fire, providing more time to escape.

Know the difference between the sound of the smoke detectors and the sound of the carbon monoxide detector.

Have a home evacuation plan for any home emergency and practice the plan with all members of the household.

If you need to warm up a vehicle, remove it from the garage immediately after starting the ignition. Do not run a vehicle or other fueled engine or motor indoors, even if the garage doors are open. CO from a running vehicle inside an attached garage can get inside the house, even with the garage doors open. Normal circulation does not provide enough fresh air to reliably prevent dangerous accumulations inside.

When camping, remember to use battery powered heaters and flashlights in tents, trailers and motor homes. Using fossil fuels inside these structures is extremely dangerous. NFPA 501, Standard on Recreational Vehicles, requires the installation of a CO detector in RVs.

Checklist for Problem Sources

  • A forced-air furnace is frequently the source of leaks and should be inspected. Check connections to flue pipes and venting systems to outside of the home for signs of corrosion, rust, gaps or holes. Check furnace filters for dirt and blockages.
  • Check all venting systems to the outside such as flues and chimneys for cracks, corrosion, holes, debris or blockages.
  • Check appliances such as water heaters, clothes dryers, kitchen ranges and ovens, wood burning stoves and gas refrigerators. Pilot lights can be a source of CO because the by-products of combustion are released inside the home rather than vented to the outside.
  • Be sure space heaters that use a flammable fuel such as kerosene are vented properly. Open a window slightly whenever using a kerosene heater. Refuel outside, after the device has cooled.
  • Barbecue grills should never be operated indoors. Stove tops or ovens that operate on flammable fuels should not be used to heat a residence.
  • Check fireplaces for closed, blocked or bent flues, soot and debris.
  • Check the clothes dryer vent opening outside the house for lint.

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