Hopcalite : A mixture of oxides of cop-per, cobalt, manganese, and silver, used in gas masks as a catalyst to convert car-bon monoxide to carbon dioxide; it is not safe if nitroparraffin vapors are present
Ralph W. Burklin & Robert G. Purington, Fire Terms: A Guide to Their Meaning and Use, National Protection Association, Boston, MA 1980 USA. (Guide: Meaning and Use, Nat Prot Association Fr Srvc - Amer) {457}