Often called the invisible killer

Carbon monoxide (CO) is a colorless, odorless gas produced when fuels such as gasoline, wood, coal, natural gas, propane, oil, and methane burn incompletely. Because it cannot be seen or smelled, carbon monoxide is especially dangerous and can quickly build up to life-threatening levels without warning.

In the home, common sources of carbon monoxide include fuel-burning heating and cooking equipment such as furnaces, boilers, fireplaces, wood stoves, gas ranges, and space heaters. Vehicles or generators running in an attached garage — even for a short time — can also produce dangerous levels of carbon monoxide. Blocked exhaust vents, damaged flues, and snow or ice covering outdoor vent pipes can allow CO to accumulate inside a home.

Carbon Monoxide Facts

• Infants, pregnant women, older adults, and people with medical conditions that limit the body’s ability to use oxygen (such as emphysema, asthma, and heart disease) can be affected by lower concentrations of carbon monoxide than healthy adults.
• Carbon monoxide poisoning can occur either from low levels over a long period of time or from high levels over a short period of time.
• Each year in the United States, fire departments respond to tens of thousands of non-fire carbon monoxide incidents in which dangerous levels of CO are detected.
• Carbon monoxide is lighter than air and mixes easily throughout a building, meaning dangerous concentrations can spread quickly.

Symptoms of Carbon Monoxide Poisoning

Because carbon monoxide is odorless, colorless, and otherwise undetectable by human senses, people may not realize they are being exposed. Early symptoms often resemble the flu — but without a fever — and may include:

• Headache
• Fatigue or weakness
• Shortness of breath
• Nausea or vomiting
• Dizziness or lightheadedness
• Confusion

At higher levels, carbon monoxide exposure can cause chest pain, vision problems, loss of consciousness, and death.

Important Safety Tips

• Install carbon monoxide alarms on every level of your home and outside all sleeping areas. Test alarms monthly and replace batteries as needed.
• Have fuel-burning appliances, chimneys, and vents inspected annually by a qualified professional.
• Keep snow, ice, leaves, and debris clear of outdoor vent pipes at all times.
• Never run vehicles, generators, grills, or propane heaters inside a home, garage, basement, or near windows and doors.
• Never use ovens, stoves, or grills to heat your home.
• If your carbon monoxide alarm sounds or you suspect CO exposure, get outside to fresh air immediately and call 911.