hose dragger
n.—Gloss: a nickname for a firefighter.
«Butler, a former Coast Guard captain, conceded he had limited experience as what’s known as a “hose dragger” but noted he has had years of planning and preparatory experience.» —“St. Paul / 4 finalists for fire chief named” by Time Nelson Pioneer Press (St. Paul, Minnesota) Sept. 27, 2007. (source: Double-Tongued Dictionary)
Another nickname, although not very complimentary, is slab-wetter. Referring to the firemen as those people who do not save structures, just wet down the concrete slab once the structure has burned to the ground.