Thanks- I've had a lousy few days (just saw my truck leave on a flatbed), almost no sleep last night, and a very, very long day at work, and, not complaining, but I was in no mood for a research project tonight. I appreciate your looking into it.

Esbit tablets have been around since WWII, and probably the primary use for decades now, at least in the US, is for powering model steam engines (or Stirling engines, in my case). In that context Esbit has made a point of assuring parents that they were non-toxic for a very long time. Clearly they have some stake in that claim.

One more: "Esbit tablets, which have a 'trade secret' formula but are probably the same as the common Hexamine tablets..."

from this page:
http://www.bushwalking.org.au/FAQ/FAQ_Efficiency.htm

I think you're refering to Trioxane. It is also toxic. The package warns it is "harmful if swallowed" and "to avoid contamination of food by loose powder. Cleanse hands after handling."

I used some last night in an experiment in my kitchen. I put my Esbit stove on top of my real stove and turned the fan on. That should take care of most of the toxicity issues. Also, I think that as long as you don't breath the fumes straight from the flame or use this stuff in a tent it won't be too bad.


Robert

This link was posted by a chemist who said he did gas chromatography on several solid fuel tablets to determine their composition.

http://66.39.74.171/cgi-bin/archives/2000/geartalk-20/config.pl?read=8233

Also, my esbit box has a caution on it stating
CAUTION: Harmful
If swallowed call doctor.
Contains methenamine.
Keep out of reach of children.

The chemical name for methenamine is HEXAMETHYLENETETRAMINE (HEXAMINE)

An interesting site on esbits, solid fuel stoves and alcohol stoves.

Esbit composition and solid fuel stoves


Esbit and other solid fuels


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Hexamethylenetetramine: aka - Hexamine, Hexy, Hexi, Hexie, Methenamine (Esbit), Hexamethylenetetramine, 3,5,7- Tetraazaadamantane, Ammonioformaldehyde,
Aceto HMT, Aminoform, Ammoform, Cystamin, Cystogen, Esametilentetramina (Italian), Formamine, Formin, Hexaform, Hexamethylenamine, Urotropin, Hexamethyleneamine, Hexamethylenetetraamine, Hexamethylentetramin (German), Hexamethylentetramine, Hexilmethylenamine, HMT, Methamin, Resotropin, Uritone, Urotropine, Esametilentetramina (Italian), 1,3,5,7-Tetraazatricyclo[3.3.1.1(3,7)]decane and C6H12N4.



NOTE: Hexamethylenetetramine releases formaldehyde, ammonia, carbon oxides, hydrogen cyanide and nitrogen oxides when burned. It is also used as a urinary tract infection antiseptic and in explosives.

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Interesting site.

Ok, I stand corrected- I was clearly thinking of trioxane and not hexamine. I had a LOT of surplus trioxane tabs stored at one point, and they had deteriorated (and disintigrated) into nasty stuff after 15 years or so... and, reading the various warnings, I disposed of them and the stove I had used them in, and resolved not to do that again.

What I had matches the photos of US miltary trioxane tabs on the site, not the photos of US military hexamine.

The evidence seems compelling that Esbits are at least largely hexamine. I've never used (or, for that matter, even seen) any of the other brands of Hexamine listed- but I know that Mamod is a big name in the steam-model circles, and I find it interesting that the box describes the tablets as "waxed". That would explain the surface texture, which leads many to believe that the tablets are wax-based. I wonder if it also explains thier long shelf life?

I have on 2 occasions tried cooking (using an Esbit stove and fuel) the contents of the little microwaveable Kraft macaroni and cheese cups by dumping the contents into a "Sierra" cup, then covering the top of the cup rather loosely with aluminum foil to help contain the heat. On both occasions, the mac and cheese took on a very unpleasant taste and smell, and I felt somewhat ill after consuming the food. Yes, it took me twice to figure out that something was wrong with this method <img src="/images/graemlins/blush.gif" alt="" /> <img src="/images/graemlins/blush.gif" alt="" />.