About Carbon Monoxide

Carbon monoxide (CO) is called the silent killer because it is colorless, odorless, tasteless and non-irritating. If the early signs of CO exposure are ignored or the CO concentration is very high, a person may lose consciousness and be unable to escape the danger. CO exposure is the leading cause of poisoning deaths in the United States. However, CO deaths are preventable.

In New York State, about 200 people are hospitalized and over 1800 people visit an emergency department because of accidental CO poisoning. Most CO poisonings occur at home. Carbon monoxide poisonings can occur anytime of year, but hospitalizations tend to occur when it is cold outside, most likely because of an increase in the use of heating appliances. About one-third of these victims are poisoned by CO from a building fire and about two-thirds are poisoned by CO that is produced by fuel-burning equipment or appliances.

Sources of CO


Malfunctioning, misused, or improperly vented fuel-burning appliances are common sources of CO poisoning in the home. These include a malfunctioning furnace or water heater, gas kitchen range used for heat, portable non-electric space heater, or a gas or charcoal briquette grill used indoors or in a partially enclosed space such as a porch. However, any appliance or heat source that produces CO and is not properly vented can cause a build-up of CO in the home.

Portable Generators

A portable generator can also be a source of CO. While a portable generator is useful for providing electricity when power is out or unavailable, it releases levels of CO that are much higher than an idling car. A portable generator should always be placed outside and away from windows and doors of any nearby building, the farther the better. One study demonstrated that 15 feet was not far enough to prevent a build-up of CO inside the home.


A running automobile releases CO in the exhaust. To prevent high levels of CO, never idle a vehicle in a garage or other enclosed structure. Another potential source of CO exposure is a blocked exhaust pipe on a running vehicle, which can cause CO to buildup inside the vehicle. The exhaust pipe can become blocked by backing into a snowbank. Whenever there is accumulated snow, make sure your vehicle's exhaust pipe is not blocked.

What About CO Alarms?

CO alarms are available for purchase. They are similar to smoke alarms and are designed to provide warning as CO levels in the air approach dangerous levels. New York State requires CO alarms in residences including single- and multiple-family homes, and in multiple dwellings such as hotels/motels, boarding houses, apartment buildings, fraternity and sorority buildings, and school dormitories. The requirements apply to structures that have an attached garage or have appliances, devices or systems that may emit CO.

Select a CO alarm which is certified by Underwriters Laboratories (UL), and is battery-powered or has a battery back-up. Place CO alarms according to manufacturer installation instructions. Test the CO alarm frequently, at least twice a year when clocks are adjusted for daylight saving time, and replace dead batteries when necessary. Read the CO alarm's owner's manual to learn about the warning sounds and how to test the device. Smoke alarms can be used for up to a decade, but CO alarms stop working after several years. Replace the alarm as indicated by the manufacturer.

A CO alarm is not a substitute for regular maintenance of fuel-burning appliances or equipment. For assistance with CO alarm placement, please contact your local fire department.


There are steps you can take to decrease the risk of CO poisoning:

  • Schedule annual maintenance on home heating systems, including furnaces, fireplaces, chimneys and other heat sources such as non-electric hot water heaters, to ensure that they are properly vented and maintained.
  • Install CO alarms in your home. Check them twice a year to make sure the batteries are working properly. Checking the CO alarms when clocks are adjusted for daylight saving time is a useful way to remember.
  • Operate portable generators outdoors and downwind of buildings. The U.S. Centers for Disease Control and Prevention recommends a distance of at least 25 feet from the house.
  • Never operate fuel-powered equipment or tools in a garage, basement, or any other enclosed space. Never use a gas range or oven for warmth.
  • Never use a gas or charcoal barbecue grill in your home or other enclosed space.
  • Make sure that non-electric space heaters are appropriately installed and vented, and that they are routinely inspected and maintained.
  • Never run a car or truck inside any garage or structure, even with the door open.

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