Please note the treatment for Methanol poisoning is drink some Ethanol.

A good document to read on Methanol

http://en.wikipedia.org/wiki/Methanol

Tony

DISCLAIMER: I am not an industrial hygenist or toxicologist. I've sent an email to US OSHA to ask what they think of using methanol or denatured alcohol in camping stoves.

I've done a bit more research on inhalation toxicity for alcohol fuels. My tentative conclusion is that with decent ventilation inhalation of methanol is probably not a problem when used outside (not in a tent). In a tent, it's probably not a problem unless you spill it. If you spill some inside a tent, stay out of the tent until it's thoroughly aired out (20 minutes to an hour?) Of course, carbon monoxide can be a serious problem if you cook in a tent.

OSHA = US Federal Occupational Safety and Health Agency
PEL = Permissible Exposure Limits based on an 8 hour average.

Methanol OSHA PEL†: TWA 200 ppm (260 mg/m3)
http://www.cdc.gov/niosh/npg/npgd0397.html
Ethanol OSHA PEL: TWA 1000 ppm (1900 mg/m3)
http://www.cdc.gov/niosh/npg/npgd0262.html

By comparison,
Carbon Monoxide:OSHA PEL†: TWA 50 ppm (55 mg/m3)
http://www.cdc.gov/niosh/npg/npgd0105.html



So methanol inhalation is significantly less toxic than CO by about a factor of 5, and ethanol is less toxic than methanol by a factor of 5.

Spilling 100 g of methanol in a tight tent will certainly exceed this PEL level of 260 mg/m^3. If we assume it all evaporates immediately in a tent of 3 m^3 volume:
Initial concentration will be:
33,000 mg/m^3. Assume the tent with door/windows open has 6 air changes per hour, and not really solving the differential equation, roughly:
after 10 minutes -- 16,000 mg/m^3
after 20 minutes -- 8000 mg/m^3
after 30 minutes -- 4000 mg/m^3
after 40 minutes -- 2000 mg/m^3
after 50 minutes -- 1000 mg/m^3
after 60 minutes -- 500 mg/m^3
after 70 minutes -- 250 mg/m^3

If you can mop up most of it before it evaporates, you can cut this time down considerably.

Last year I bought a can of denatured alcohol from REI with a brand name called 'Crown' - there was no content information on the can that I could understand. So I did a search on the Crown website and found the MSDS stating it has the following ingredients:
65-75% METHANOL (67-56-1)[200-659-6],
20-30% ETHANOL (64-17-5)[200-578-6],
< 10% ISOPROPANOL (67-63-0)[200-661-7],
< 10% METHYL ISOBUTYL KETONE (108-10-1)[203-550-1]

Seems like the SLX brand, that is available from Home Depot, might be a bit safer.

Tony wrote:

>A good document to read on Methanol
>http://en.wikipedia.org/wiki/Methanol

Seems methanol is widely used as a fuel in motor sports. I haven't seen a lot of obituaries about racers and pit crews dying from its effects.

Nonetheless, the wikipedia article states the ingestion of only 10 ml is enough to cause blindness. That's hardly a sip full.

Not to harp, but, I'd really be leery about having methanol around small children on a camping trip (said by someone who will take it on his own hikes). Methanol is something you'd keep locked away from children in your house, like ant poison. Camping with kids can be chaotic enough without keeping track of small plastic bottles (oh, so attractive to little ones) filled with poisonous fuel left near the stove.

If I were camping with small children I'd go with a canister stove - forget alcohol and the rest. Wait until they get older. I don't trust anyone, including myself, to be perfectly attentive. One of the first rules of safety is to guard against mistakes.

Of course we're talking about two different paradigms: the serious hiker vs. "let's take the kids for an outing". Perhaps I dwell on this to disabuse myself of carrying over behaviors from one to the other without examining certain assumptions of behavior and risk.

Bill, "If I were camping with small children I'd go with a canister stove". I agree. Even pure ethanol could be dangerous for small children.

Tony and Roger, just wanted to say thanks for the effort, time and insight. Great to have that data at hand!

Has anyone noticed a difference in the performance of ethanol and methanol in cold weather. Ethanol is more energy dense, but methanol has a lower evaporation point and may be easier to get started at the low end of usable temperatures for alcohol stoves. This seems like a situation where a mix of methanol and ethanol might be best, analagous to mixing isobutane and propane in a canister stove.

Any thoughts?

Alcohol stoves in cold weather are usually primed to get things going. Once that is accomplished (30 seconds?), IMHO, I don't think vapor pressure makes much difference. In a Caldera Cone - or any tight windscreen environment - things are going to be plenty warm.

As Greg said.

Cheers

The reason why dangerous and other additives are added to pure ethanol is so that people cannot easily produce alcoholic drinks by watering it down to a reasonably safe level. Ethanol is dangerous initself but the human body can tolerate and metabolise it to a very much greater degree than the other additives. Thus "metho" can be sold cheaply without any government alcohol tax.

Gordon
Australia

I'm just researching alcohol stoves and I'm a bit confused. There seems to be 3 commonly used alcohols, all of which have problems.

Pure ethanol works good but 95% Everclear is expensive and everything else seems to contain dangerous additives.

Methanol seems easier to get a yellow HEET, but it is considerably less efficient than Ethanol and IPA and there are health concerns.

IPA seems to be too dangerous to ones health to use?

So what do I use? Based on fuel efficiency I'd like to use ethanol but I'm in Canada and don't know where to get it. Can you get pure denatured ethanol at the local hardware store?

Hi, Dan-
Bottom line, there's no such thing as "pure" denatured alcohol. The "denatured" part of the phrase is specifically to make the alcohol un-pure, if you will. That said, you can pick up regular ol' denatured alcohol at the local hardware. If you like, check the MSDS for the denatured alkys you have available to find out how much of what "methyl ethyl bad stuff" it has. IPA is just a pain to burn, mega sooty.

Hi Dan,

I stand to be corrected but I have read on other forums that denatured is not available in Canada and you can only get Methanol.

Tony

Thanks guys.....I guess I'll pick up a bottle of Methanol (Heet) and see how that goes. I'm just considering switching to an alcohol stove (from canister) at this point. I'm a little dismayed at how much less efficient methanol (ie. grams per litre boiled) vs. ethanol. I'm going to visit a few stores in the next 2 days and see what I can find.

Hi Mates, you guys sure did a fantastic job on these articles. Really indepth information. Thank You so much!!!

Another Denaturant that was found in Denatured Alcohol was camel urine. Roger sited minibulldesign as a source of information that indicated that bleach was also used.

(quote):However, lest you are wondering whether this is all made up, a quote from the noted alcohol stove enthusiast Tinny of MiniBullDesigns in America is worth reading. You should note that he is only talking about those versions of denatured alcohol which he has been able to buy in America. We are sure other versions exist.(end quote)


I found this info from the same source and I quote:

(Quote)(from minibulldesign site)
If you want to do this to your white box stove you can either buy some wick from my site or you can send the little girl to tinny and he will do the dirty work for you for $5.00 plus shipping---congratulations Bill you have a very nice design ----Tinny---got ideas?

OH-- I DO NOT recommend DENATURED ALCOHOL. I can't speak for every area but in my area they keep using different stuff to denature it, like camel urine and the results can be dramatic. I use HEET in the yellow bottle.(end quote)

I don't think I'll be using Denatured again. How do they get away with using such additives.

Hi Dan

> I don't think I'll be using Denatured again. How do they get away with using such additives.
I have no idea! But it's your government, not mine. If you don't like what your government permits, get it changed.

Here in Australia the contents of 'denatured alcohol' or 'methylated spirits' seem to be rather more tightly regulated - the issue of public health is taken seriously.

OK, OK, I am stirring - but only slightly.

Cheers

...it's your government, not mine. If you don't like what your government permits, get it changed.

Here in Australia the contents of 'denatured alcohol' or 'methylated spirits' seem to be rather more tightly regulated

Hi Roger,

You weren't suppose to take me seriously. =)