It appears that you can accidentally & unsafely have an unsafe occurrence with a 'Flameless ration heater'.
The United States Department of Transportation (DOT) Federal Aviation Administration (FAA) conducted testing and released a report which in summary states "... the release of hydrogen gas from these flameless ration heaters is of a sufficient quantity to pose a potential hazard on board a passenger aircraft." This testing was performed on commercial grade 'heater meals' which consisted of an unenclosed flameless heat pouch, a bag of salt water, a styrofoam saucer/tray and a meal in a sealed, microwavable/boilable bowl. Source
Assuming a quantity of dry fuel exist to build a fire, could I use a 'Flameless ration heater' to safely ignite a fire for cooking and heating?