Carbon Monoxide Alarms

Often called the invisible killer, carbon monoxide is an odorless, colorless gas created when fuels (such as gasoline, wood, coal, natural gas, propane, oil, and methane) burn incompletely. In the home, heating and cooking equipment that burn fuel are potential sources of carbon monoxide. Vehicles or generators running in an attached garage can also produce dangerous levels of carbon monoxide.

The dangers of CO exposure depend on a number of variables, including the victim's health and activity level. Infants, pregnant women, and people with physical conditions that limit their body's ability to use oxygen (i.e. emphysema, asthma, heart disease) can be more severely affected by lower concentrations of CO than healthy adults would be.  A person can be poisoned by a small amount of CO over a longer period of time or by a large amount of CO over a shorter amount of time.

In 2016, local fire departments responded to an estimated 79,600 carbon monoxide incidents, or an average of nine such calls per hour. This does not include the 91,400 carbon monoxide alarm malfunctions and the 68,000 unintentional carbon monoxide alarms.

Data from the Center of Disease Control and Prevention’s (CDC’s) National Center for Health Statistics shows that in 2017, 399 people died of unintentional non-fire carbon monoxide poisoning. 

Source: NFPA's Applied Research Division

Symptoms of CO poisoning

CO enters the body through breathing. CO poisoning can be confused with flu symptoms, food poisoning and other illnesses. Some symptoms include shortness of breath, nausea, dizziness, light headedness or headaches. High levels of CO can be fatal, causing death within minutes.

The concentration of CO, measured in parts per million (ppm) is a determining factor in the symptoms for an average, healthy adult.

  • 50 ppm: No adverse effects with 8 hours of exposure.
  • 200 ppm: Mild headache after 2-3 hours of exposure.
  • 400 ppm: Headache and nausea after 1-2 hours of exposure.
  • 800 ppm: Headache, nausea, and dizziness after 45 minutes; collapse and unconsciousness after 1 hour of exposure.
  • 1,000 ppm: Loss of consciousness after 1 hour of exposure.
  • 1,600 ppm: Headache, nausea, and dizziness after 20 minutes of exposure.
  • 3,200 ppm: Headache, nausea, and dizziness after 5-10 minutes; collapse and unconsciousness after 30 minutes of exposure.
  • 6,400 ppm: Headache and dizziness after 1-2 minutes; unconsciousness and danger of death after 10-15 minutes of exposure.
  • 12,800 ppm: Immediate physiological effects, unconsciousness and danger of death after 1-3 minutes of exposure.
Source: NFPA's Fire Protection Handbook, 20th Edition.

Symptoms of CO poisoning

CO enters the body through breathing. CO poisoning can be confused with flu symptoms, food poisoning and other illnesses. Some symptoms include shortness of breath, nausea, dizziness, light headedness or headaches. High levels of CO can be fatal, causing death within minutes.

The concentration of CO, measured in parts per million (ppm) is a determining factor in the symptoms for an average, healthy adult.

  • 50 ppm: No adverse effects with 8 hours of exposure.
  • 200 ppm: Mild headache after 2-3 hours of exposure.
  • 400 ppm: Headache and nausea after 1-2 hours of exposure.
  • 800 ppm: Headache, nausea, and dizziness after 45 minutes; collapse and unconsciousness after 1 hour of exposure.
  • 1,000 ppm: Loss of consciousness after 1 hour of exposure.
  • 1,600 ppm: Headache, nausea, and dizziness after 20 minutes of exposure.
  • 3,200 ppm: Headache, nausea, and dizziness after 5-10 minutes; collapse and unconsciousness after 30 minutes of exposure.
  • 6,400 ppm: Headache and dizziness after 1-2 minutes; unconsciousness and danger of death after 10-15 minutes of exposure.
  • 12,800 ppm: Immediate physiological effects, unconsciousness and danger of death after 1-3 minutes of exposure.
Source: NFPA's Fire Protection Handbook, 20th Edition.

Reproduced from NFPA's website, © NFPA 2021.