Effect of firetruck noise on firefighters' hearing

Noise exposure of Minneapolis city firefighters was measured in 3 categories of fire apparatus. Maximum SPL of 110 db(A) and mean duration of 23 min/day do not exceed OSHA guidelines. The means pure-tone ac HTLs of a Group A of 17 men of 23-28 yrs with 0.75-2 yrs firefighting experience did not differ significantly from those of a comparable group of older men of 30-35 yrs with 8.25-10.9 yrs firefighting experience. Mean HTLs for both groups exceeded those of men of comparable age groups with no noise exposure tested by Corso, but at the lower frequencies only (0.5-4 kc/s), not at the higher (6-8 kc/s). Previous military and concurrent recreational noise exposure may have masked differences between Group A and B.