Heaters in Tents: The Carbon Monoxide Rules

In an emergency, call 911.

The short version: never use fuel-burning appliances in enclosed spaces; carbon monoxide is odorless. That covers propane and butane heaters, camp stoves, liquid-fuel and gas lanterns, charcoal grills and generators, whether the enclosed space is a tent, a camper or a vehicle. The rest of this article explains why, what the official guidance actually says, and how to stay warm without one.

What carbon monoxide is

Carbon monoxide (CO) is a gas you can't see or smell. The U.S. Consumer Product Safety Commission (CPSC) describes it as deadly, colorless, odorless and poisonous, and notes that it comes from the incomplete burning of fuels. Engine-powered equipment, including generators and cars, produces it too.

The Centers for Disease Control and Prevention (CDC) lists the most common symptoms as headache, dizziness, weakness, nausea, vomiting, chest pain and confusion. CPSC adds sleepiness to its camping-specific list, and its CO fact sheet notes that early symptoms resemble the flu without a fever. CDC warns that people who are sleeping, or who have been drinking, can die from CO poisoning before they ever have symptoms.

Everyone is at risk, according to CDC. Infants, older adults, and people with chronic heart disease, anemia or breathing problems are more likely to get sick from CO.

Why tents, campers and vehicles are a problem

A tent or camper is a small, enclosed air space, and you're often in it for hours while asleep. CPSC says people die every year from CO poisoning caused by portable camping heaters, lanterns or stoves used inside tents, campers and vehicles. Its guidance is direct: don't use fuel-burning portable heaters or lanterns while sleeping in enclosed areas such as tents, campers and vehicles. CPSC adds that this is especially important at high altitudes, where the risk of CO poisoning increases.

A common assumption is that cracking a vent or opening the door makes it OK. CDC's report on two camping deaths in Georgia in 1999 addressed this directly. It concluded that camping stoves, camping heaters, lanterns and charcoal grills should never be used inside a tent, camper or other enclosed shelter, and that opening tent flaps, doors or windows is not enough to prevent CO from building up. The same report says that when you use fuel-burning devices outdoors, their exhaust should not vent into an enclosed shelter.

Charcoal deserves its own mention. CDC notes that burning charcoal of any color produces CO and says never to burn it indoors. Bringing a still-warm grill into a tent or vestibule to take the edge off the cold is exactly the kind of use the agencies warn against.

What the official guidance says to do

Here is the guidance from CPSC and CDC that applies at camp:

• Keep fuel-burning gear out of sleeping areas. CPSC says never to use portable fuel-burning camping equipment inside a home, garage, vehicle or tent. CDC's home guidance likewise says never to use a portable gas camp stove indoors.
• Turn it off before you turn in. CPSC's guidance specifically targets heaters and lanterns used while sleeping.
• Keep generators outside and away from openings. CDC says never to run a generator inside a home or garage, even with doors and windows open, and to keep it outdoors more than 20 feet from windows, doors and vents. CPSC's March 2026 winter safety release says never to operate a portable generator in any enclosed space. Campground quiet hours and generator rules vary, so check with the campground too.
• Mind vehicle exhaust. CDC warns never to run a car or truck inside an attached garage, even with the door open. It also says that if you drive with a tailgate open, you should open vents or windows so air moves through the vehicle, and that the exhaust system should be checked every year.
• Know the symptoms. CPSC says to see a doctor if you or a family member develops cold- or flu-like symptoms while camping.

If a CO alarm sounds or someone has symptoms, CPSC's instruction is to get outside to fresh air right away and call 911. Don't go back in until emergency responders say it's safe, and don't try to find the source yourself. For more, see CDC's CO poisoning basics.

Electric heaters are a different risk, not a free pass

Electric heaters don't burn fuel, so they don't make CO, but they carry fire and burn risks. If you use one in a cabin or an RV on shore power, CPSC's March 2026 release says to plug it directly into a wall outlet (never a power strip), keep it clear of anything that can burn, and never leave it running unattended in a confined space. A heater left running while everyone sleeps is unattended. Follow the manufacturer's instructions and the campground's rules.

Safer ways to stay warm

Most of a warm night comes from what's under and around you, not from a heat source.

• Match your sleeping bag to the conditions. The National Park Service (NPS) advises using a sleeping bag that fits you and matches the temperature and weather where and when you're camping. For winter backcountry trips, Glacier National Park says a four-season sleeping bag and an insulated pad are a must.
• Insulate from the ground. NPS recommends laying down a ground pad before your sleeping bag, because moisture from the ground under you will draw heat from your body and leave you cold. Mount Rainier National Park includes a full-length insulated sleeping pad in its list of winter essentials.
• Go to bed dry. NPS suggests changing into dry clothes before bed. It also advises against burying your head inside your sleeping bag, because your breath adds moisture that makes you colder over time.
• Dress in layers. NPS recommends layers you can add when you're cold and remove before you overheat, with wool or synthetic fabrics instead of cotton, which doesn't keep you warm once it's wet. The National Weather Service (NWS) notes that air trapped between loose-fitting layers helps insulate, and that wet clothing makes your body lose heat much faster. Pack a spare set of dry clothing in a sealed bag, as NPS suggests.
• Fuel your body. NPS notes that hunger and physical activity can reduce your body's ability to keep itself warm, and suggests insulated containers to keep food and water from freezing.

A battery CO alarm: backup, not permission

A portable, battery-operated CO alarm is a reasonable thing to bring along, especially in a camper or RV. CPSC says CO alarms are available for recreational vehicles and should be used, and notes that the Recreation Vehicle Industry Association requires CO alarms in motor homes and trailers. When you shop, CPSC recommends battery-operated alarms, or alarms with battery backup, that meet the current UL 2034 safety standard.

Keep two limits in mind:

• An alarm doesn't make a heater safe to use. CPSC says a CO alarm can provide some added protection but is no substitute for proper use and upkeep of appliances that can produce CO. The rule doesn't change: never use fuel-burning appliances in enclosed spaces.
• Test it, and know what the test does. CPSC's March 2026 release recommends testing CO alarms monthly and replacing batteries as needed. Its fact sheet notes that the test button checks the circuitry, not the accuracy of the sensor, so replace the alarm on the schedule the manufacturer gives. CDC adds that detectors should be replaced every five years or as the manufacturer recommends.

Before your next cold-weather trip

Check the forecast, pack a sleep system rated for the coldest night you expect, bring dry layers, and plan to cook and run any fuel-burning gear outside, away from your tent or camper. If you bring a CO alarm, put fresh batteries in it before you leave.

Sources

• CDC, Carbon Monoxide (CO) Poisoning Basics: https://www.cdc.gov/carbon-monoxide/about/index.html
• CDC, MMWR, "Carbon Monoxide Poisoning Deaths Associated with Camping — Georgia, March 1999": https://www.cdc.gov/mmwr/preview/mmwrhtml/mm4832a1.htm
• CPSC, Portable Heaters & Camping Equipment: https://www.cpsc.gov/Safety-Education/Safety-Education-Centers/Carbon-Monoxide-Information-Center/Portable-Heaters--Camping-Equipment
• CPSC, Carbon Monoxide Fact Sheet: https://www.cpsc.gov/safety-education/safety-guides/carbon-monoxide/carbon-monoxide-fact-sheet
• CPSC, "CPSC Issues Winter Weather Safety Tips to Prevent Fires and Carbon Monoxide Poisoning" (March 16, 2026): https://www.cpsc.gov/Newsroom/News-Releases/2026/CPSC-Issues-Winter-Weather-Safety-Tips-to-Prevent-Fires-and-Carbon-Monoxide-Poisoning
• NPS, What to Bring — Camping: https://www.nps.gov/subjects/camping/what-to-bring.htm
• NPS, Be Winter Ready for Your Adventure: https://www.nps.gov/articles/winterweather.htm
• NPS, Glacier National Park, Winter Wilderness Camping: https://www.nps.gov/glac/planyourvisit/winterbccamping.htm
• NPS, Mount Rainier National Park, Winter Safety: https://www.nps.gov/mora/planyourvisit/winter-safety.htm
• NWS Boulder, Wind Chill Safety: https://www.weather.gov/bou/windchill

Last verified: November 1, 2026.