A Guide to Prevent Carbon Monoxide Poisoning

Guide to Carbon Monoxide Poisoning (CO Poisoning)

CO Detectors 


CO Sources    

CO Removal   

Health Effects




Poison Control Centers

Poision Control Centers in the U.S.
Poision Control Centers in Canada

Buy CO Detectors


How Carbon Monoxide (CO) Detectors Work

CO detectors measure CO levels in the environment and sound an alarm to warn you to ventilate the affected area.

Two basic types of CO detectors
CO detectors are either battery operated or electric. Most CO detectors on the market use one of the following three sensor types.

1. Electrolytic Sensor Detectors - This type of sensor is extremely sensitive to detecting CO in the home. Although it is the most efficient type of CO detector, it is rarely used due to its significant cost.
2. Colorimetric Sensor Detectors – This type of sensor measures the build-up of CO over time. Once the alarm has been sounded it takes up to 48 hours to reset.
3. MOS Detectors (Metal Oxide Semiconductor Sensor) – This type of sensor is very popular because it can detect other gases besides CO such as chlorine bleach and silicones.

CSA and UL-Approved Devices Change
As of 2010 both the CSA and UL standards prohibit a CO detector from sounding the alarm at relatively low levels. This change was made to reduce the amount of false alarams that fire departments were dealing with as a result of detectors with low level settings. There are low-level detectors commerically available, however these units are not certified by the CSA or the UL. Currently, CSA and UL-approved devices will be set to sound the alarm at CO concentrations above 70 ppm. This is significantly higher than the exposure levels recommended by government health guidelines.

CO fire detectors
These electronic detectors sound against a fire by sensing CO levels in the air. They should not be confused with CO detectors used to protect people from CO poisoning.

  • CO fire detectors are effective for deep-seated, smoldering fires.
  • Smoke detectors are better at reacting to smoke that rises.

Choosing a Battery Operated or Electric CO Detector
You may be wondering whether to purchase a battery operated CO detector or one that runs on a household electric current.

There is no difference in cost between the battery operated and the electrically run CO detector.


  • The battery operated type is easier to install and can be placed anywhere in the house.
  • The electric type can only be installed near an outlet or hard wiring.


  • The electric type requires no maintenance.
  • The battery operated type needs periodic maintenance such as changing the battery every year.

Exposure display feature

  • The electric type uses a solid-state sensor that purges itself and re-samples for CO continuously keeping you up to date on the CO levels in the house.
  • The battery operated type uses a passive sensor that reacts to the prolonged exposure to CO gas.

Reset Feature

  • The electric type resets immediately after the CO problem has been corrected.
  • The battery operated type must be manually reset. This may involve removal of the sensor pack. The reset time will depend on concentration and duration of the CO exposure.


  • The electric type will not work during a power outage unless equipped with a battery backup.
  • The battery operated type can be depended on in during an outage or any emergency, as long as the battery is charged.



Carbon Monoxide Poisoning - Carbon Monoxide Detectors - FAQ's - Articles - Resource Links - Site Map
Webmaster Advertisement