Cobalt exposure level and variability in the hard metal industry of Japan.
Cobalt, used as a binder for tungsten carbide, has been demonstrated to be toxic to the lung and to be a sensitizer of the bronchial airways among hard metal workers. To determine cobalt exposure levels in 9 job groups at a hard metal factory, 935 samples were collected from 356 workers. The arithmetic means of 8-hr time-weighted averages were more than 50 micrograms/m3 (American Conference of Governmental Industrial Hygienists' threshold limit value) in the powder preparation, rubber press, and shaping groups. The within-worker and between-worker components of exposure variation were estimated for each job group using the random effects analysis-of-variance model. The geometric standard deviations indicating the within-worker and between-worker components ranged from 1.88 to 2.77 and 1.00 to 2.31, respectively.
Department of Occupational Health, Osaka Prefectural Institute of Public Health, Japan.
S
S
Kumagai
Y
Y
Kusaka
S
S
Goto
D000395:Air Pollutants, Occupational / Q000032:analysis*; D000704:Analysis of Variance; D003035:Cobalt / Q000032:analysis*; D004784:Environmental Monitoring; D006801:Humans; D007564:Japan; D008452:Maximum Allowable Concentration; D008669:Metallurgy; D016273:Occupational Exposure; D009790:Occupations
D000395:Air Pollutants, Occupational; D003035:Cobalt