Carbon Monoxide Poisoning in the Mountains

Carbon monoxide (CO) is an incredibly dangerous colorless, odorless gas. It can be found in the air any time you burn fuel in cars, trucks, small engines, stoves, lanterns, grills, fireplaces, gas ranges or furnaces. 

Carbon monoxide is dangerous because it displaces oxygen in the blood. This deprives vital organs -- the heart and brain -- of oxygen. Large amounts of CO can overcome an individual in a matter of minutes, causing the person to lose consciousness and suffocate.

Symptoms of CO exposure/poisoning include headache, fatigue, dizziness, drowsiness, or nausea. The most important thing to do when you feel these things is to take yourself out of the situation that may be causing the symptoms. For example, turn off your stove and open up your vestibule.

Approximately thirty deaths every year in North America are attributed to carbon monoxide poisoning in tents. These poisonings tend to happen when people have lanterns, stoves or charcoal fires in an enclosed or poorly ventilated space.

As mountaineers, we commonly cook in our tents. The weather can be extremely nasty, and it's comfortable to cook and eat inside. But this definitely puts us at more risk.

A walled camp on Denali.
Expedition climbers almost always cook inside their tents.

There are a few really simple rules that you can follow to avoid carbon monoxide poisoning in a tent:

1. When cooking in a tent, the vestibule should be open. It should be easy to breathe.
2. Individuals in the tent should be sitting up. Nobody should ever lay down while the stove is running. If you wish to lay down, turn off the stove first.
3. Lanterns, heaters and charcoal grills don't belong in tents.

This really can be the silent killer. We spend a lot of time worrying about objective hazards in the mountains, but then there's this...something that can kill you very quickly, and very easily, if you don't follow the rules.

--Jason D. Martin