Carbon Monoxide Safety: Symptoms, CO Detectors, Generators and Winter Risks
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How we wrote this: A plain-English summary of the CDC's Carbon Monoxide (CO) Poisoning Basics page (reviewed October 26, 2026), checked October 29, 2026. If a CO alarm sounds or you suspect poisoning, get outside to fresh air and call 911.
Why CO is so dangerous
The CDC says carbon monoxide is an odorless, colorless gas that kills without warning. Each year more than 400 Americans die from unintentional CO poisoning not linked to fires, more than 100,000 visit an emergency department and more than 14,000 are hospitalized. Furnaces, portable generators, charcoal grills and other fuel-burning devices produce it.
Symptoms
The most common symptoms are headache, dizziness, weakness, upset stomach, vomiting, chest pain and confusion. The CDC says these are often described as "flu-like." People who are asleep or intoxicated can die before they notice any symptoms.
Everyone is at risk, but infants, older adults and people with chronic heart disease, anemia or breathing problems are more likely to get sick.
CO detectors
- Install battery-operated or battery-backup CO detectors near every sleeping area.
- Check the batteries when you change your clocks in spring and fall. (Daylight saving time ends Nov. 1, 2026; see our DST guide.)
- Replace detectors per the manufacturer's instructions or every 5 years.
- Consider a model with a digital readout that shows the highest CO level.
Furnaces, appliances and chimneys
- Have your heating system, water heater and other gas, oil or coal appliances serviced by a qualified technician every year.
- Make sure gas appliances are vented properly.
- Never heat your house with a gas oven. Don't burn anything in an unvented stove or fireplace.
- Have your chimney checked or cleaned every year.
- Never burn charcoal indoors, and don't use camp stoves or flameless chemical heaters inside.
Generators during outages
- Never run a generator inside your home or garage, even with doors and windows open.
- Run it outdoors, more than 20 feet from windows, doors and vents.
- Use a battery-powered or battery-backup CO detector while it runs.
Cars
- Have the exhaust system checked every year.
- Never run a vehicle in an attached garage, even with the door open.
- With a tailgate open, open vents or windows so exhaust isn't pulled inside.
See also: home heating fire safety, winter storm alerts.