[Status of noise in small-scale factories having press machines and hearing loss in workers]

A study on noise and hearing loss was conducted in 36 small-scale factories where press machinery is actively used. Noise levels in working environments were measured in 34 factories. Of those measured, two (6%), eight (24%) and 24 (71%) factories were classified into control classes I, II and III, respectively, according to guidelines established for the prevention of noise-related disorders. Furthermore, personal exposure levels to noise were measured for 23 workers. Twenty-one (91%) of those workers measured were exposed to 85 dB(A) or higher, (the occupational exposure limit for an 8-hour exposure period). Maximum exposure levels were found to be at 102 dB (A). Hearing tests were then conducted on 97 male workers at those 36 factory sites. Twenty (21%), 30 (31%) and 10 (10%) of the workers measured were classified into a "precursory symptom group", a "slight hearing loss group" and a "medium to serious hearing loss group", respectively, based on the aforementioned guidelines. It was found that as workers' ages increased, the percentage of workers having some degree of hearing loss increased. Specifically, it was found that there was some level of hearing loss for 93% of those studied aged in their 50's, and up to 100% in those aged in their 60's.