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Carbon Monoxide (CO) Information


Carbon monoxide (CO) is a poisonous, colorless, odorless, and tasteless gas that is often a result of incomplete burning of natural gas or other organic substances.

Carbon monoxide, even in low concentrations, can be deadly (refer to table below.) This dangerous gas displaces oxygen in the air and in your blood, thereby depriving your heart, brain, and other vital organs of oxygen. Carbon monoxide can kill in a matter of minutes, therefore, it is important to have CO detection units installed in your home. If you suspect carbon monoxide levels within your home, call 911!

Carbon Monoxide (CO) Facts & Guidelines

  • Carbon monoxide cannot be detected by smell, taste, or sight.
  • Carbon monoxide levels can be monitored by installing detection units within the home that are strategically placed near furnaces, fuel fired water heaters, and other gas appliances.
  • Combination smoke and CO detector are available, however, it is best to buy them as separate units. Because smoke rises, smoke detectors are best mounted on the ceiling. Adversely, CO detectors should be placed at eye-level, where CO measurements will be noticed by the unit owner.
  • Place a CO detector on every floor, or AT LEAST near the bedrooms.

Carbon Monoxide (CO) PPM Levels & Symptoms

 Concentration Level*   Effects of CO Poisoning Comments 
 0 - 1 PPM  none, no symptoms considered to be normal background levels 
 1 - 9 PPM none - monitor air closely  maximum indoor air quality - short term 
 9 - 35 PPM minimal effects possible over time  OSHA - 8 hour limit 
 35 - 100 PPM flu like symptoms, headache  mild exposure, but potentially dangerous 
 100 - 200 PPM dizziness, drowsiness, vomiting  OSHA - 15 minute exposure limit 
 200 - 400 PPM frontal headache, fatigue  medium exposure, but not safe to occupy 
 400 - 800 PPM unconsciousness, brain damage  extreme exposure, life threatening after 3 hrs. 
 800 - 1600 PPM nausea, convulsions, death  very dangerous and hazardous - death 1 hr. 
 12, 000 PPM death in 1 to 3 minutes  extremely hazardous environment 

*Carbon monoxide is measured in parts per million (PPM.)

When choosing your detector, look for a unit that has the following features:

  • Battery backup mechanism - plug-in with internal charging battery.
  • Digital display - the unit should measure and display the PPM reading multiple times per minute.
  • "Peak-level" memory feature -
    • Units with "peak-level" memory will record and remember the highest level of CO that has been detected since the last device reset. The peak-level feature is particularly important because it allows unit-owners to catch levels of CO that may be "peaking" when you are not looking at the device.

      For example, if the carbon monoxide level is highest at a particular time of day: maybe a neighbor in an adjoining unit leaves their car running in the garage in the morning, allowing CO to enter your home through the ductwork and ventilation. As another example, If your furnace is having intermittent operational issues, perhaps while you are at work or asleep, peak-level can help you catch a problem before the furnace malfunctions for an extended period of time and CO levels become deadly.
  • For deaf and hard-of-hearing people, look for a light-emitting unit.