Anyone know what the "proprietary additive" is that they put in this stuff? Probably petroleum distillates.

http://zenstoves.net/MSDS/MSDSHeet.htm

Methanol is pretty toxic on it's own. I like to think I'm getting away from as many nasty chemicals as I can when I backpack.

Ethanol gives you more BTUs per weight and you can get it non-poison flavored. Go with the pure, food grade or drinking ethanol and you avoid the petroleum distillates they use for de-naturing.