Preventing explosions of hydrogen gas inhalers

Production and excretion of hydrogen (H₂) gas in human was reported in 1969, since then it has been regarded as non-toxic molecule. For preventive and therapeutic medical uses, a possible treatment for cancer was reported and another article was published on how H₂ acts as a therapeutic antioxidant by selectively reducing cytotoxic oxygen radicals. A variety of H₂ gas inhalers have been available in the market for hospital and home uses. However, H₂ is odorless and flammable or explosive ignited by static electricity. We have examined the safety of a variety of H₂ gas concentrations from the viewpoint of flammability and explosion. We have also measured concentrations of H₂ gas inhalers in the market respectively. This paper also details how to control H₂ gas concentration for preventing explosions.