Carbon Monoxide is the Silent Cold Weather Killer

Carbon monoxide poisoning can kill without warning, as your family sleeps.

Because CO gas has no warning properties, even at toxic or life threatening levels, it is considered a silent killer. And since so many deaths occur as the result of defective or poorly operated home heating devices, CO has been termed the “silent, cold weather killer.”

Carbon Monoxide is the Silent Cold Weather Killer

Although not always experienced, the initial symptoms of CO are similar to the flu (but without the fever). But it can also mimic other ailments like gastric flu or stomache upset, the symtoms include:

  • Dizziness
  • Fatigue
  • Headache
  • Nausea
  • Irregular breathing

It is critical to note that death from CO poisoning can result with some or all of these symptoms never being experienced, in which case the overexposed victim simply “falls asleep” and never regains consciousness.

Carbon monoxide is produced by devices that burn fuels. Therefore, any fuel-burning appliance in your home is a potential CO source. Electrical heaters and electric water heaters, toasters, etc., do not produce CO under any circumstances. Under normal circumstances, CO should not be detectable in the typical home or workplace.

When appliances are kept in good working condition, they produce little CO. But improperly operating or improperly vented appliances can produce elevated — even fatal — CO concentrations in your home. Likewise, using kerosene heaters or charcoal grills indoors, or running a car in a garage, can cause levels high enough to result in CO poisoning.

Common sources of CO include the following wood or gas fueled appliances:

  • Room heaters
  • Furnaces
  • Charcoal grills
  • Cooking ranges
  • Water heaters
  • Automobiles run in closed garages
  • Fireplaces
  • Portable generators
  • Wood burning stoves

How can I prevent CO poisoning?

Dangerous levels of CO can be prevented by proper appliance maintenance, installation, and use. Timely inspections of potentially CO-producing equipment, and the use of CO toxic level concentration alarms, are also key to avoiding a CO fatality.

To avoid CO poisoning, follow these tips:


  • Proper installation is critical to the safe operation of combustion appliances. All new appliances have installation instructions that should be followed exactly. Local building codes should be followed as well.
  • Appliances designed to be vented should be vented properly, according to manufacturers’ instructions.
  • Adequate combustion air should be provided to ensure complete combustion.
  • All combustion appliances should be installed by professionals.


  • A qualified service technician should perform preventive maintenance on homes with central and room heating appliances (including water heaters and gas dryers) annually. The technician should look at the electrical and mechanical components of appliances, such as thermostat controls and automatic safety devices.
  • Chimneys and flues should be kept free of blockages, corrosion, and loose connections.
  • Individual appliances should be serviced regularly.
  • Kerosene and gas space heaters (vented or unvented) should be cleaned and inspected to ensure proper operation.

Appliance Use:

  • Follow manufacturers’ directions for safe operation.
  • Make sure the room where an unvented gas or kerosene space heater is used is well ventilated; doors leading to another room should be open to allow added ventilation.
  • Never use an unvented combustion heater overnight or in a room where you are sleeping.
  • Never use charcoal grills inside a home, tent, camper, or unventilated garage.
  • Don’t leave vehicles running in an enclosed garage, even to “warm up” a car on a cold morning.


In addition to professional preventive maintenance on a potentially CO-producing appliance, timely inspections should be performed by the homeowner to identify signs of possible CO problems. Look for the following conditions, and if detected, have a professional service technician fully examine the unit for safety and continued use.

  • Rusting or water streaking on vent/chimney.
  • Loose or missing furnace panel.
  • Sooting on internal or attic spaces.
  • Loose or disconnected vent/chimney connections.
  • Debris or soot falling from chimney, fireplace, or appliance.
  • Loose masonry on chimney.

In addition, there are signs that might indicate improper appliance operation which include:

  • Decreasing hot water supply.
  • Furnace unable to heat house or runs constantly.
  • Sooting, especially on appliances.
  • Unfamiliar or burning odor.
  • Increased condensation inside windows.


Next to prevention of the production of toxic CO gas, the best defense against this deadly killer is a CO alarm. These devices can detect toxic concentration of CO in the air, sound an alarm, and thereby save lives.