By Teri Simpson of Optimum Preparedness


What’s the Real Story about Alcohol, Propane and Butane?
Questions have come up about the safety of alcohol stoves, propane stoves and butane stoves being used indoors and in UGs. I’d like to speak into this subject and maybe help clear up some misconceptions. What gives me the authority to do this? I’ve sold and used alcohol stoves for over two decades and have given uncountable safety lessons on their use. I researched the safety of fuels for use in restricted quarters (like in UGs). I’ve consulted with scientists (not the kind that play scientists on TV; the real kind with graduate degrees and years in laboratories.)

So first, a brief review of short chain hydrocarbon molecules.

Methanol is a one-carbon molecule, ethanol is a two-carbon chain and both burn extremely cleanly. Propane is a three-carbon hydrocarbon chain and butane is a four-carbon hydrocarbon chain molecule. All four of these products are considered “short chain hydrocarbon molecules” and all burn very cleanly. When burned, they turn into carbon dioxide and water while releasing heat. Longer chain hydrocarbons in the six to twelve carbon range make up what we call gasoline. Candle wax is mostly paraffin which is made up of chains that are about twenty carbons long. The shorter the chain and more access to oxygen, the cleaner the burning. Very long chains like heavy oil and candle wax do not burn completely and so produce free carbon (which we see as smoke or soot) and some of the carbon that is burnt is only partially combined with oxygen so instead of CO2, you get CO (carbon monoxide) which, in too great a concentration, is lethal. That is why you never use wood, charcoal, or coal fires indoors unless they are vented directly to the outside. (And why you want to have a carbon monoxide detector in your UG.)

When you breathe, your body gives off carbon dioxide and water. Plants give off carbon dioxide and water. So if we consider all four of the fuels safe to burn, what makes one better than another to use indoors in a normal kitchen or in an enclosed area?

First and foremost you need to know if there is enough ventilation to have a flame of *any* kind? Fire consumes the oxygen out of the air; same as you. Most fire burns oxygen faster than you, and so the fire and you are in competition for the available oxygen in the air. Get in a station wagon, roll the windows up tight and cook a pot of rice on a stove: the stove flame will use up the oxygen, and you will pass out and maybe die. It is not the FUMES from the stove that kill you. It is because the fire consumed the oxygen from the air and didn’t leave enough for you.

A single candle flame in a UG setting is using up roughly the same amount of oxygen as a person sitting there and breathing. Love to have lots of candles burning to give it that romantic setting? That might be OK in your home that has lots of ventilation, but if you want to light several candles in your UG would the ventilation support that many people sitting around breathing? So bottom line, unless you know how much fresh air is moving into your UG every hour, you probably should not have any open flame at all.

Naturally any above ground kitchen has enough normal airflow for us to have a propane or natural gas (which is mostly methane) stove. We don’t think anything about having a gas stove in our kitchen do we? Is it giving off harmful fumes? No, only carbon dioxide and water. You can set a Porta Chef on your counter or table and use it in your kitchen. Again no harmful fumes, only carbon dioxide and water are given off.

You might hear someone say (as I have) “Oh, it is BAAAAAD to breathe butane”. Well duh! Of course it is bad to breathe butane. Yes, butane is what the Porta Chef stove uses to make the fire for you to cook on. But note that the butane canisters are leak proof – no free butane gets into the air. The ONLY way to breathe that butane would be to find some way to spray it out of its sealed container, maybe into a plastic bag and then try to breathe it in. Obviously, major stupid.


People operate under the assumption that alcohol (methanol or ethanol) is totally safe to use in closed quarters. This is not true, and is a dangerous assumption. Most alcohol stoves do not operate with a sealed pressurized system: they have a can (with or without wicking material in it) into which you pour the alcohol, which you then light so you can cook. This is how the Trangia stoves that I sold all through the 1990’s worked and also how the Origo alcohol stoves work.

But before you can light that now open can of alcohol, it is evaporating into the air, and it is not good to breathe alcohol vapors, particularly methanol (also known as wood alcohol) which is what most stoves use. Any methanol that you absorb through your skin or by breathing it in your body will promptly metabolize into a highly toxic chemical called formaldehyde. Normally, it is just a short time before filling the can and lighting it, so not much evaporates into the air and its not a big problem. But what happens after you put the flame out?

The Trangia stove burner has a gasketed lid that you screw on so that the alcohol left in the burner doesn’t evaporate out into the air (this is good). What about the Origo? Does it have an airtight lid on its burners? The answer is No it does not. The burner has a piece of metal that goes over the opening but it is not airtight. So from the time you quit cooking dinner at night until the time you get up to make coffee in the morning, you have alcohol evaporating into your air. On a boat (where alcohol stoves are most often used) you have port holes and the cabin door opening and closing and the breeze off the water. No shortage of fresh air to dilute the toxic methanol fumes and blow them away. However, I have never noticed much of a fresh breeze in the UGs I have visited. So one of these unsealed alcohol stoves will put way more toxic stuff into the air in your UG than a big stack of sealed butane canisters used by the Porta Chef stove.

Another issue with any alcohol stove is this: the flame burns almost completely clear and it is hard to see, particularly in the light. Because of this, it is easy to mistakenly think that the burner has gone out, causing you to want to refill it so you can continue to cook. I tell anyone using an alcohol stove to hold their hand directly over the burner for a 10-count before EVER adding fuel to the burner. I have personally seen what happens when someone pours alcohol into a burner that was not out yet, and still burning. The fuel exploded outwards and upwards in a ball of flame covering the person in droplets of liquid fire. It was lucky this person was wearing a heavy coat and that I was only a few feet away. I got the flames doused quickly but even so, my friend had to be taken ashore and air-lifted off Orcas Island and then flown by helicopter to the burn unit at Harbor View in Seattle. She was lucky that someone was there; she was lucky that there were still 911 dispatchers to call, helicopters to respond, and hospitals to go to. In a real UG situation, none of that would be true, and it would have been an ugly scenario, much worse than it was.

I sold alcohol stoves, I own alcohol stoves, I have quite a supply of methanol. I have given uncountable safety speeches about using alcohol stoves to people. Ask me what stove I use, and I will tell you that I use the Porta Chef stove with the butane canisters. I like to say it is Dummy Proof. You cannot put the canister in wrong. It is light weight. It doesn’t need special-sized pots or pans – whatever you have will work.

And a year or more worth of fuel fits in approximately a 2' x 2’ x 32” space. I put up some of the Porta Chef fuel for Y2K back in 1999. I checked it out a short time ago, and it was still in perfect condition and worked just as though it were still brand new, so I know the fuel will store indefinitely.

Teri Simpson
Optimum Preparedness
Good ol’ Yelm, WA


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