Carbon monoxide is a colorless, odorless and tasteless gas. It results from the incomplete burning of fuels such as gas, natural gas, kerosene, liquid petroleum, oil, charcoal, coal and wood. CO detectors are needed to help forewarn you of toxic pollutants in your home. A CO detector which meets the Underwriters Laboratories standard (ANSI/UL 2034-02) is recommended.




Carbon Monoxide (CO)
Fact Sheet

Q1: What is carbon monoxide (CO)?
Carbon monoxide is a colorless, odorless, and tasteless gas. It results from the incomplete burning of material such as gas, natural gas, kerosene, liquid petroleum, oil, charcoal, coal, wood, and tobacco. The major source of CO emissions is gasoline-powered automobiles.

Q2: How does carbon monoxide affect my body?
Carbon monoxide prevents oxygen in the blood from being carried throughout the body, causing asphyxiation. CO remains in the body for a long time - the half-life of CO in the body is about five hours.

Q3: What are the symptoms of CO poisoning?
The effects depend on how much carbon monoxide is in the air, how long it is breathed, and how healthy, active, and sensitive to CO an individual is. Exposure to CO is worse for older people, fetuses, and people with heart, circulatory, or lung disease.

Low concentrations of CO can cause headache, loss of alertness, flu-like symptoms, nausea, fatigue, fast breathing, confusion, disorientation, and overall weakness. In addition, it can cause chest pain in people with heart disease. CO can also impair judgment and cause decreased learning ability in school children.

High concentrations of CO can cause coma (unconsciousness) and death.

The longer a person breathes CO, the worse the effects. For example, breathing air which has 400 parts per million (ppm) of CO in it will cause a headache after one or two hours, but can kill some people after three hours.

Q4: What should I do if I think someone has been exposed to CO indoors?
First, get the person or persons fresh outdoor air to breath - fast. Next, get emergency medical care fast. When you call for help, report that you think there is carbon monoxide poisoning. After the emergency, you may have to have appliances which burn gas or fuel (like the furnace, oil burner, stove or hot water heater) inspected, and repaired if needed.

Q5: How much carbon monoxide is normally found inside the home?
It can vary a great deal. A house with a gas furnace working properly may have a CO concentration in the air of 1-2 parts per million (ppm). But having all four gas burners on the stove on for 20 minutes may cause the level to rise to 35 to 120 ppm. A kerosene heater that is working properly can produce an indoor concentration of 20 ppm. A furnace that isn't working properly can raise the level to 1,000 ppm - high enough to cause death in a couple of hours.

Q6: How much carbon monoxide is found outdoors? Is there a safe level of CO?
Except near streets and highways, the CO concentration in outdoor air rarely rises above 1-2 ppm. Government standards call for less than 9 ppm CO (over an 8-hour average) in living areas, and less than 35 ppm during any one-hour period. These guidelines may not provide sufficient protection for people with heart or lung problems.

While there is no known safe level of carbon monoxide, some CO is found naturally in the outdoor environment. Those traces exist beyond the control of regulatory efforts.

Q7: Can CO affect pets?
Yes. Just like people, pets need oxygen. Because pets sometimes spend more time in the home, they may show the effects of CO poisoning before people do.

Q8: Since I can't see or smell CO, are there clues that it might be building up?
Yes...sometimes. Windows that are more fogged up or covered with water droplets than usual may be a sign that the furnace or another fuel-burning appliance is putting out CO. With oil- or wood-burning furnaces, the smell of unburned fuel may mean that CO is in the air. If you or others have health problems in the home or car - like headache, dizziness, watery eyes, coughing, or irritated nose or throat - which disappear when you leave and come back when you return, CO could be the cause.

Q9: How can I detect and measure carbon monoxide?
There are many different devices, from inexpensive home-use carbon monoxide detectors which plug in or run on batteries, to very expensive scientific CO monitors.

Q10: Should I have a carbon monoxide detector at home or in my vehicle?
Yes. Many different brands and models are available. Select one that meets the Underwriters Laboratory (UL) standard, which requires that it sound a loud (85 decibel) alarm within 90 minutes if the CO concentration is at 100 ppm, within 35 minutes at 200 ppm, and within 15 minutes at 400 ppm. Remember, having a carbon monoxide detector in the home is not a reason to postpone regular inspection of the home system by a qualified service person.

New York City Department of Health & Mental Hygiene
Bureau of Environmental Investigations


Copyright 2007