Abstract: The use in a chemical mixture of a predominant amount (but less than 100%) of potassium superoxide or other similar material to produce a breathing gas for use in respirators, submarines, mines, or the like. The combining chemical absorbs carbon dioxide, but either does not release oxygen or releases a smaller amount of oxygen than does the potassium superoxide. Thus, the environment is effectively cleared of carbon dioxide, but the tendency of the potassium superoxide to over-produce oxygen is obviated since its performance in this respect is reduced by virtue of its combination with a non-oxygen or low-oxygen producing chemical and, most important, the volume of oxygen produced for consumption remains responsive to the individual's respiration quotient, as hereinafter explained.