KmH
Engineer
The exothermic (gets hot) chemical reaction flameless ration heaters (FRH) use to make steam (heat) produces hydrogen gas (H2) as a by product (about 1/3 cu ft). Hydrogen is flammable.I was thinking maybe getting a flameless ration heater was possible, but it may be considered an "incindiery" which would be prohibited. I'm sure I wouldn't be allowed to bring aboard some types of camping gear like propane or butane cylinders. I have brought chemical hand warmers on board, but those are pretty safe.
Mg + 2H2O → Mg(OH)2 + H2 [+ heat]
I'm pretty sure the US Department of Transportation does not allow the use of FRHs on public transportation.
Using a FRH in the field allows the hydrogen to disperse, unlike a confined space like a Coach car.
The odor a FRH produces that some find objectionable is from the magnesium hydroxide gas
It is sort of ironic that solid magnesium hydroxide - Mg(OH)2 - has fire retarding properties.