Road trips often include a night or two in unusual places.
You might nap in the car at a rest area, sleep in a camper van or spend a cold night in a tent.
Many of these situations involve engines, stoves, lanterns or heaters.
All of them can produce a gas you cannot see, smell or taste.
That gas is carbon monoxide, and it can be deadly.
This guide explains where it comes from and how to stay safe, using guidance from MedlinePlus and the Environmental Protection Agency.
What carbon monoxide is
MedlinePlus, from the National Library of Medicine, describes carbon monoxide as a gas with no odor or color.
It is very dangerous and can cause sudden illness and death.
The EPA adds that it is toxic and impossible to see, taste or smell.
Because of that, it can harm you before you are aware it is there.
The effects vary from person to person.
The EPA explains that age, overall health, the amount of gas and the length of exposure all play a part.
Where it comes from on a road trip
Carbon monoxide is found in combustion fumes.
MedlinePlus names common sources, including cars and trucks, lanterns, stoves, gas ranges and heating systems.
Several of these travel with you on a road trip.
- Your car's exhaust.
- Gas camp stoves.
- Fuel-burning lanterns.
- Portable heaters that burn gas or kerosene.
- Portable generators.
The danger grows in enclosed spaces.
MedlinePlus explains that fumes can build up in places without a good flow of fresh air.
A tent, a car cabin, a camper or a closed garage can all become that kind of place.
Know the symptoms
MedlinePlus lists the most common symptoms of carbon monoxide poisoning.
- Headache.
- Dizziness.
- Weakness.
- Nausea.
- Vomiting.
- Chest pain.
- Confusion.
It is often hard to tell when someone has carbon monoxide poisoning.
The symptoms can look like those of other illnesses, such as the flu.
The EPA notes that symptoms can clear up after people leave the place where they were exposed.
If everyone in a tent or camper feels sick at the same time, think about carbon monoxide first.
Why sleepers are at special risk
This point matters most on a road trip.
MedlinePlus warns that people who are sleeping or intoxicated can die from carbon monoxide poisoning before they have symptoms.
A person who is awake may notice a headache or dizziness and move to fresh air.
A person who is asleep may never get that warning.
That is why the safety rules below focus on where you sleep.
Never idle the car in a garage
The EPA gives a clear instruction: do not idle the car inside a garage.
This applies to a hotel or vacation rental garage just as much as your own.
- Do not warm up the car with the garage door closed.
- Do not sit in a running car inside any enclosed space.
- Move the car outside before you let it run.
Idling also wastes fuel.
Our guide on warming up your car in winter explains why long warm-ups are rarely needed.
Sleeping in the car
A quick nap at a rest area can be the right choice when you feel drowsy.
Our guide on drowsy driving on long road trips explains why stopping beats pushing on.
A few habits keep that nap safe.
- Park in an open area, never inside a garage or enclosed structure.
- Avoid sleeping with the engine running whenever you can.
- Use blankets or a sleeping bag to stay warm instead of the heater.
- If you notice an exhaust smell inside the cabin, have the exhaust system checked by a mechanic.
A pre-trip car check is a good time to ask a mechanic about any exhaust smell or noise.
Camp stoves, lanterns and heaters
Camping gear makes cooking and staying warm easier.
Fuel-burning gear also creates carbon monoxide.
Since fumes build up where fresh air does not flow, keep this gear out of closed spaces.
- Use camp stoves outdoors, never inside a tent or a closed car.
- Use battery-powered lanterns inside the tent instead of fuel-burning ones.
- Do not run a fuel-burning heater inside a tent or a closed vehicle.
- Follow the manufacturer's instructions for every piece of fuel-burning gear.
In bear country, cooking away from the tent is also a food safety rule.
Our guide on camping in bear country explains where to cook and sleep.
On cold nights, a warm sleeping bag and dry layers are safer than a heater.
Our guide to mountain road trips covers how cold high-country nights can get.
Portable generators
Some campers and RV travelers bring a generator for power.
The EPA places a strong warning at the top of its carbon monoxide page.
Never use a portable generator inside homes, garages, crawlspaces, sheds or similar areas.
Deadly levels of carbon monoxide can build up quickly in those spaces.
The EPA adds that the gas can linger for hours, even after the generator shuts off.
The agency also shares a Consumer Product Safety Commission warning.
Do not use a generator inside, even with the doors and windows open.
Run it only outside and far away from windows, doors and vents.
At a campground, that also means keeping it away from your own tent and your neighbors'.
Carbon monoxide alarms
MedlinePlus notes that a carbon monoxide detector can warn you about high levels of the gas.
The EPA shares the Consumer Product Safety Commission's recommendation of alarms on each level of a home.
On a road trip, the same idea can travel with you.
- If you sleep in a camper or RV, make sure it has a working carbon monoxide alarm.
- Test the alarm and check the batteries before the trip.
- In a vacation rental, look for a working alarm when you arrive.
Follow the alarm maker's instructions for testing and replacement.
What to do if you suspect carbon monoxide
If an alarm sounds or several people feel sick at once, act fast.
- Get everyone into fresh air right away.
- Turn off the engine, stove, heater or generator if you can do it safely.
- Call 911 if anyone has symptoms.
- Do not go back inside until the space has been checked.
Tell the medical team what fuel-burning equipment was running.
A carbon monoxide checklist for the road
- Car never idling in a garage or enclosed space.
- Naps taken in open areas, with blankets instead of the engine.
- Camp stoves and fuel lanterns used only outdoors.
- No fuel-burning heater inside the tent or car.
- Generator outside and far from windows, doors and vents.
- Working carbon monoxide alarm in any camper or rental.
- Symptoms reviewed with everyone in the group.
The bottom line
Carbon monoxide gives no smell and no warning, and sleepers are most at risk.
Keep engines, stoves, heaters and generators out of closed spaces.
Use an alarm where you sleep, and move to fresh air at the first sign of trouble.
These simple rules keep every night of the road trip a safe one.
Sources and Further Reading
- MedlinePlus, National Library of Medicine: Carbon Monoxide Poisoning — supports what carbon monoxide is, its common sources, how it builds up without fresh air, the symptoms, the risk for people who are sleeping and the value of a detector.
- US Environmental Protection Agency: Carbon Monoxide's Impact on Indoor Air Quality — supports the warning not to idle a car inside a garage, the portable generator warnings, the health effects and the alarm recommendation.