[Survey of noise exposure level of national forestry workers]

Eighty-one national forestry workers who were using chain saws, log cutters, log cutting machines, bush cleaners, timber-collecting cable machines and forklifts were examined for their level of noise exposure in a working day by using a portable sound meter. And their noise exposure levels Leq (8 h) for a year were estimated based on the measured noise levels and on the number of noise exposure days and hours in a year recorded in their work documents. The survey was made from July to December, 1988. The maximum noise levels with all the machines except a case of the forklift were above 100 dB, and with most chain saws they were above 110 dB. The amount of time that workers were exposed to the noise of logging and lumbering with chain saws, cutting by bush cleaners and timber-collecting cable machines without a cabin was longer than the allowable time for 90 dB and 95 dB. The number of noise exposure days in a year is fewer than reported in the past. The estimated Leq (8 h) for 32 out of 34 lumbermen surveyed was more than 85 dB, and for 5 lumbermen the Leq (8 h) was more than 90 dB. From these results, it can be concluded that there is a danger of noise induced hearing loss in national forestry workers using chain saws, log cutters, log cutting machines and timber-collecting cable machines without a cabin in 1987.