Can You Fart Yourself To Death?
Posted July 23, 2008 by Mister Knowitall

Tom S. in Maryland writes: A few hours after making and eating a tasty cauliflower curry, I found myself thinking about the story going around the internet about the man in the small bedroom who farted so much he suffocated on the methane. Can that really happen?

Well, Tom, that particular story is an urban legend, but you asked if it can happen. Let’s do the math.

Assume the man’s room was tiny, just big enough for a twin bed, a small dresser/table, and that’s it. Say 8 feet long by 5 feet wide by 7 feet tall. That’s going to be 280 cubic feet. We can deduct a generous 40 cubic feet for the air displaced by his furniture and himself, leaving 240 cubic feet of air.

According to an article over at Rough Equivalents, where they calculated how many farts it would take to fill a football stadium, the average fart is 110 milliliters of gas and a cubic foot is 28,316 milliliters.

Wikipedia states the composition of a fart is up to 10% methane and up to 10% oxygen. So if we put that fart at 10% methane and 0% oxygen, you’d be putting 11 milliliters of methane into the room per fart.

The Canadian Centre for Occupational Health and Safety’s health effects of methane page states that it takes a methane volume of 140,000 parts per million to cause “harmful effects”. The current composition of air contains 1.745 parts per million of methane, so we only need to raise that by 139,998.255 parts per million.

Assuming 240 cubic feet of air volume, you have 6,795,840 milliliters of volume. To reach 140,000 parts per million, even accounting for the slight natural methane already in air, you’d need 951,410 milliliters of methane. If the average fart has a maximum of 11 milliliters of methane, it would take 86,491 farts to generate that much methane. That’s a little over 1 fart every second for 24 hours.

Still, at 110 milliliters per fart, it would only take 61,780 farts to displace all the regular air in his room, which would be 2.14 farts every second for 8 hours. But you only need to drop the oxygen level below 18% to start having “harmful effects” and the composition of air is only 20.95% oxygen as it is. So to drop the oxygen concentration below 18%, he’d only need to fart enough to replace 16.39% of the air in the room, or 1,113,838 milliliters of fart gas. That’s only 10,126 farts and then he only needs to fart 21 times a minute during 8 hours of sleep.

That’s patently impossible. But what about carbon dioxide, you ask? An average male at rest will exchange about 6 liters of air in a minute from breathing, converting 4-5% of it from oxygen to carbon dioxide. In that room, we have 6796 liters of air. Each minute, he converts 300 milliliters of oxygen to carbon dioxide.

To bring the oxygen level below 18% and begin having “harmful effects,” he’d need to convert 200.48 liters of oxygen to carbon dioxide. Eight hours of breathing would convert… 144 liters. This would lower the oxygen content to 18.83% and raise the CO₂ levels up to slightly over 2%, which might make him breathe a little faster near the end. He’d still need to fart thousands of times in that 8 hours to get the oxygen level down to 18%, but it wouldn’t raise the methane level high enough to cause asphyxiation, even in combination with the carbon dioxide from his breathing.

And this is all assuming his room is airtight rather than merely poorly ventilated. Any ventilation would require more breathing and farting to do the job.

So, Tom, you can sleep easy. While your furnace or a portable generator might put out enough methane or carbon dioxide to suffocate you while you sleep, your own breathing and farting couldn’t do the job.