Just watched a 1937 movie Draegerman Courage about mine rescuers. Not having come across the term before I checked it out in OED.
Etymology: < the name of A. B. Dräger (1870–1928), German scientist, inventor of a type of breathing apparatus + man n.
Earliest cite is 1918, latest 1958, frequency 1. (Unrevised, entry dates to 1972.) Most of the cites are Canadian but I don’t know if that’s significant. Is this term for a mine rescue worker still current?