Never use stoves or heaters inside a tent: carbon monoxide at camp
Carbon monoxide (CO) is an odorless, colorless gas. According to the CDC, 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. Many household items produce it, including furnaces, portable generators and charcoal grills. On a cold camping night or during a power outage, the temptation is to bring the heat source inside. Tents, campers and cars are exactly the small spaces where CO builds up fastest.
The rules (CDC)
- Never use a charcoal grill, hibachi, lantern, or portable camping stove inside a home, tent, or camper.
- Never burn charcoal indoors, and never use a portable gas camp stove indoors.
- Never use a generator inside your home or garage, even if doors and windows are open. Only use generators outside, more than 20 feet away from windows, doors and vents.
- Never run your car or truck inside a garage attached to a house, even with the garage door open.
- Never heat your house with a gas oven.
- Install battery-operated or battery back-up CO detectors near every sleeping area in your home, and replace them following the manufacturer's instructions or every 5 years.
How fast it happens: tests from Japan
Japan's National Institute of Technology and Evaluation (NITE), a government product-safety body, tested burning equipment inside tents:
| Test | Time to exceed 200 ppm CO |
|---|---|
| Campfire inside a two-room tent | About 9 minutes |
| White-gas portable stove inside a solo tent with the fly closed | About 15 minutes |
NITE notes that at 0.02% (200 ppm), CO causes headaches. Both tests passed that level well inside half an hour. "Just for a few minutes" and "the door is open a bit" are not safety plans.
Evacuation shelters, cars and generators
NITE's 2025 warning addresses disasters directly: don't use cassette gas stoves in tight spaces such as tents or cars used as evacuation shelters, because nearby things can catch fire and incomplete combustion can cause CO poisoning. Never run a portable generator in a shed, storeroom, car or tent. Of product accidents reported to NITE from 2020 to 2024, 21 involved portable generators; NITE says those accidents typically came from indoor use, often hurt several people at once, and had a high share of deaths. NITE has also described a fatal case in which two people died using a charcoal brazier inside a campground cabin.
Symptoms
CDC lists headache, dizziness, weakness, upset stomach, vomiting, chest pain and confusion as the most common symptoms; they're often described as "flu-like." People who are sleeping or drunk can die before they have any symptoms, which is why sleeping near a running heater is so dangerous.
What to do
- If you feel unwell while a stove or heater is running, ventilate first (NITE's advice), and get everyone into fresh air.
- If symptoms don't improve, call for help. CDC: call 911 or Poison Control at 1-800-222-1222, or a health care professional right away.
Where each piece of gear belongs
Our summary of the CDC and NITE rules:
| Gear | Where to use it |
|---|---|
| Campfire, charcoal grill, hibachi | Outdoors only, in the open; never under a closed-in tarp, in a tent or in a cabin |
| Camp stove, lantern, tent heater | Outdoors only; never inside a tent, camper or car |
| Cassette (butane) stove during an outage | Follow the manufacturer's instructions on ventilation; not in tents or cars used as shelters |
| Portable generator | Outdoors only, more than 20 feet from windows, doors and vents |
Staying warm without flame (our suggestions)
- A sleeping bag rated for the season, and an insulated sleeping pad: much of the cold comes up from the ground.
- A hat, dry socks and layers you can add before you get cold.
- A hot drink from a thermos before bed.
- In a home power outage, gather the family under blankets or sleeping bags in one room.
Everyday
Cook and run lanterns outside, in the open air. On cold nights, warm yourself with sleeping bags, pads and layers, not flame.
When it counts
In a power outage or an evacuation, you keep generators and stoves outside, away from where people sleep.
Sources and when we checked them
- CDC, Carbon Monoxide (CO) Poisoning Basics (checked 2026-10-31)
- CDC, What to Do to Protect Yourself During a Power Outage (checked 2026-10-31)
- NITE (National Institute of Technology and Evaluation, Japan), camping safety test results (PDF, in Japanese, 2021) (checked 2026-10-31)
- NITE, products for power and gas outages: precautions (PDF, in Japanese, 2025-08-28) (checked 2026-10-31)
- NITE, product safety education handbook: combustion appliance accidents (in Japanese) (checked 2026-10-31)
- NITE, preventing carbon monoxide poisoning accidents (PDF, in Japanese, 2013) (checked 2026-10-31)
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