Fuel for a C-Ration Stove. (background) A tablet of blue Trioxin, which caused fumes which irritated the eyes and respiratory tract if ventilation holes weren’t large enough. In that case, a whole heat tab had to be used. With a properly vented stove, only half a Trioxin heat tab was needed to heat the meal and then the other half could be used to heat water for coffee or cocoa. A small chunk of C-4 explosive could also be substituted for the Trioxin tablet for faster heating. It would burn hotter and was much better for heating water.