Carbon Monoxide (CO)

Carbon monoxide is the leading cause of poisoning deaths in the United States each year. It is usually a silent and unsuspected killer.

What is carbon monoxide?
Carbon monoxide is a gas formed as a by-product of combustion. It is colorless, odorless, and tasteless and gives no warning of its presence. Therefore, it can kill before you even know it is there.

What actually happens in carbon monoxide poisoning?
Carbon monoxide is taken into the body by the lungs through breathing. Carbon monoxide prevents oxygen from saturating the blood cells and nourishing the body. Without oxygen-rich blood, the brain, heart, and other tissues will not survive. Smaller amounts of carbon monoxide damage the body.

What are the sources of carbon monoxide?
Carbon monoxide is present wherever fuel is burned. It is produced by unvented kerosene heaters; gas space heaters; leaking chimneys and furnaces; back-drafting from furnaces, gas water heaters, gas dryers, gas stoves, wood stoves, and fireplaces; charcoal grills; camp lanterns; automobile exhaust fumes from vehicles left running in attached garages; and lawnmowers.

What are the health effects?
At low concentrations, fatigue in healthy people and chest pain in people with heart disease is often experienced. At higher concentrations, impaired vision and coordination, disorientation, weakness, headaches, dizziness, confusion, sleepiness, vomiting, and nausea are prevalent. The symptoms are easily and frequently diagnosed as being flu-like, clearing up after leaving the place where one is exposed. Carbon monoxide poisoning can be fatal at high concentrations.

What can you do to avoid carbon monoxide poisoning?
A few common sense things you can do to avoid exposure to carbon monoxide include the following:

• Never use an unvented gas heater indoors.
• Never use an unvented kerosene heater indoors.
• Never use a charcoal grill indoors.
• Never use an oven or cooktop for heating purposes.
• Never allow individuals to ride in a pickup camper.
• Never sit in a parked car with the engine running and the windows rolled up.
• Never idle a car inside a garage.
• Never use gas lanterns and heaters in a camper unless they are vented to the outside.

You should also have a thorough and periodic check of all possible sources of combustion appliances/equipment to eliminate potential sources of carbon monoxide. Some checkpoints include the following:

• Clean your chimney yearly before the start of the heating season.
• Be sure the chimney is free of blockages, corrosion, and loose connections.
• Have a professional check all heating appliances for proper function. Service your individual appliances regularly.
• Proper installation is critical to the safe operation of combustion appliances.
• Carefully follow the manufacturer's instructions on installation. Follow all building codes as well.
• Correctly install all vented appliances based on the manufacturers' instructions.
• Follow operating instructions as recommended by the manufacturer.
• Your local utility company will normally check your home for sources of carbon monoxide for a nominal charge. Schedule them well before the heating season.
• Consider purchasing a vented space heater when replacing an unvented one.
• Make sure a room where an unvented gas heater is located is well ventilated. Open doors to help facilitate proper ventilation.
• Never use an unvented combustion heater overnight or in a room where you are sleeping.
• Use the proper fuel in kerosene space heaters.
• Over a gas stove, install and use an exhaust fan that is vented to the outdoors.
• Open the flue/damper when a fireplace is in use.
• Choose proper sized wood stoves that are certified to meet EPA emission standards. Make certain that doors on all woodstoves fit tightly.
• Replace your furnace filters monthly.
• Be sure to properly vent all your heating appliances to the outdoors.
• Learn to recognize a properly adjusted gas flame--a crisp blue flame. If the flame is orange, contact your utility company immediately.

Are there signs that might indicate improper appliance operation?
The following are some visible signs:

• Increased condensation on the inside of windows
• Strange or burning odor
• Sooting or ghosting on appliances and throughout the home
• Furnace running constantly or unable to heat the house
• Decreased hot water supply

There are invisible signs as well. They include the following:

• Internal appliance damage or malfunctioning components
• Improper burner adjustment
• Hidden blockage or damage in chimneys

Only a trained service technician can detect hidden problems and correct these conditions!

Are there visible signs that might indicate a carbon monoxide problem?
Very few visible signs are apparent, but you might watch for the following:

• Visible rust or stains on vents and chimneys
• Improper connections on vents and chimneys
• An appliance that makes an unusual sound or emits an unusual smell
• An appliance that continues to shut off. The cause might be a safety device installed in the appliance that prevents operation if an unsafe condition develops. If this happens, contact a service person to have the appliance checked.

What safety devices are installed on some appliances that would prevent operation in an unsafe condition?

• Vent safety shutoff systems have been used since the late 1980s on furnaces and vented heaters. They help prevent operation when they are blocked or disconnected.

   

• Oxygen depletion sensors (ODSs) have also been installed on unvented gas space heaters since the late 1980s. ODSs cease the operation of the appliance in conditions with incomplete combustion.

These devices are not substitutes for regular professional servicing. Also, many older appliances do not have such devices and therefore continue to operate when conditions develop that are unsafe.

What are carbon monoxide detectors?
A carbon monoxide detector identifies low levels of carbon monoxide in the home. Exposure to a low concentration of carbon monoxide over several hours can be as dangerous as exposure to high levels for a few minutes. The new detectors will detect both conditions. The Consumer Product Safety Commission (CPSC) recommends the installation of at least one carbon monoxide detector with an audible alarm near the sleeping area in the home. It is also advisable to install one on every level of the home. Additional detectors should be placed near any major gas-burning appliance such as a furnace or a gas water heater. Do not locate them closer than 5 feet. Also, do not place them near cooking or bathing areas. Place most detectors near the ceiling. It is important to follow the manufacturer's installation instructions for proper placement within a given area.

Select a detector that is Underwriters Laboratories Inc. (UL) listed.

What should you do if you experience symptoms that you think could be carbon monoxide poisoning or if your carbon monoxide detector sets off the alarm?

• Get fresh air immediately. Open the doors and windows and turn all gas-powered appliances off at once. Check to be sure everyone is accounted for and that no one is experiencing symptoms of carbon monoxide poisoning.
• Go to an emergency room if anyone is experiencing symptoms of carbon monoxide poisoning. Tell the physician you suspect carbon monoxide poisoning. If such poisoning has occurred, it can often be diagnosed by a blood test done soon after exposure.
• Be prepared to answer the following questions for the doctor:
  • Do your symptoms occur only in the house?
  • Do they disappear or decrease when you leave home and reappear when you return?
  • Is anyone else in your household complaining of similar symptoms? Did everyone's symptoms appear about the same time?
  • Are you using any fuel-burning appliance in the home?
• Do not reenter the premises or restart any of the appliances until all possible problems are corrected by a qualified service technician.

  For additional information on carbon monoxide poisoning contact
  

• The American Lung Association at http://www.lungusa.org/air/carbon_factsheet.html
• The U.S. Consumer Product Safety Commission

Publication 2235
Extension Service of Mississippi State University, cooperating with U.S. Department of Agriculture. Published in furtherance of Acts of Congress, May 8 and June 30, 1914. Ronald A. Brown, Director