Carbon Monoxide Alarms 101

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Carbon monoxide alarm

What is Carbon Monoxide, and how is it produced?

  • Often called the "silent killer," carbon monoxide (CO) is a deadly, colorless, odorless, poisonous gas.
  • It is produced by the incomplete burning of various fuels, including coal, wood, charcoal, oil, kerosene, propane, and natural gas.
  • Products and equipment powered by internal combustion engines -- think portable generators, cars, lawn mowers, and power washers  -- also produce CO.

What are the symptoms of CO poisoning?

Because CO is odorless, colorless, and otherwise undetectable to human senses, people may not know they are being exposed. The initial symptoms of low- to moderate-CO poisoning are similar to the flu (but without the fever):

  • Headache
  • Fatigue
  • Shortness of breath
  • Nausea
  • Dizziness

 High-level CO poisoning results in progressively more severe symptoms, including:

  • Mental confusion
  • Vomiting
  • Loss of muscular coordination
  • Loss of consciousness
  • Ultimately death

Symptom severity is related to both the CO level and the duration of exposure. For slowly developing residential CO problems, occupants and/or physicians can mistake mild to moderate CO poisoning symptoms for the flu, which sometimes results in tragic deaths. For rapidly developing, high-level CO exposures (e.g., associated with use of generators in residential spaces), victims can rapidly become mentally confused, and can lose muscle control without having first experienced milder symptoms; they will likely die if not rescued.

Are CO alarms reliable?

CO alarms always have been and still are designed to alert before potentially life-threatening levels of CO are reached. The safety standards for CO alarms have been continually improved, and currently-marketed CO alarms are not as susceptible to nuisance alarms as earlier models.

How should a consumer test a CO alarm to make sure it is working?

Consumers should follow the manufacturer's instructions. Using a test button tests whether the circuitry is operating correctly, not the accuracy of the sensor. Alarms have a recommended replacement age, which can be obtained from the product literature or from the manufacturer.

How should I install a CO Alarm?

  • CO alarms should be installed according to the manufacturer's instructions.
  • If your home has several levels, including basements and any attics that are used, you will need detectors on each levels. 
  • Place a CO detector within 15 feet of each bedroom door.  

What should you do when the CO alarm sounds?

Never ignore an alarming CO alarm. It is warning you of a potentially deadly hazard. If the alarm signal sounds do not try to find the source of the CO:

  • Immediately move outside to fresh air.
  • Call your emergency services, fire department, or 911.
  • After calling 911, do a head count to check that all persons are accounted for.
  • DO NOT reenter the premises until the emergency services responders have given you permission. You could lose consciousness and die if you go in the home.
  • If the source of the CO is determined to be a malfunctioning appliance, DO NOT operate that appliance until it has been properly serviced by trained personnel.

Do you know the sound of your smoke alarm versus your CO alarm?

Carbon Monoxide alarms sound different than smoke alarms. 

(SOURCE: Centers for Disease Control and Prevention)