The hearing level of 508 workers exposed to steady-state noises with levels of 95 and 100 dB(A) is compared with the hearing of 918 employees who have not been exposed to occupational noises. The workers were selected from 8000 workers in different industries, according to the following criteria: exposure to steady-state noises in the same workplace during their whole professional career, no otological previous history. Results are given for exposure durations ranging from 5 to 30 years for ages ranging from 20 to 50 years. The severe injury resulting from the exposure to the two noise levels considered is apparent from the comparison of the percentages of deafness observed after 30 years exposure: 12% for exposure to 95 dB(A) and 20% for exposure to 100 dB(A) but only 1% for the non exposed group having the same average age. These results have to be complemented for noise levels close to 90 DB(A). Several comments are also made with regard to the practice of audiometry in the occupational environment.