Provided is a portable heating device comprising a combustion-powered heater, a regulator, and an oxygen depletion sensor. The combustion-powered heater may be supplied by an associated fuel source and may comprise a combustion region comprising a catalytic surface. The regulator may be adapted for fluid communication with the associated fuel source. The oxygen depletion sensor may comprise a burner and a temperature detector. The burner may be in fluid communication with the regulator and may be adapted to combust fuel form the regulator with air to produce a flame. The temperature detector may be adapted to detect the temperature of the flame and may be adapted to selectively render the combustion-powered heater non-functional.