MSHA approved for use in methane-air mixture and UL listed for Division I and II, class I, Group C and D environments. For use in gas-air mixtures of acetone, butane, benzene, diethyl ether, ethyl and methyl alcohols, gasoline, methane (natural gas), naphtha and propane. Approved also for use in dust-air mixtures of class II, Group G. Designed so that if lamp is broken, electrical circuit will be opened before filament can ignite these flammable or explosive gas-air mixtures in the surrounding atmosphere.