AN INVESTIGATION OF OCCUPATIONAL METAL EXPOSURE IN THERMAL SPRAYING PROCESSES

A cross-sectional study of 34 workers engaged in thermal spraying at s ix worksites was undertaken in order to determine levels of exposure t o and uptake of metals during different metal spraying activities. Lev els of exposure to cobalt, chromium and nickel were highest in plasma sprayers and, an occasions exceeded UK Occupational Exposure Limits. E xposure to metals during detonation gun and electric are spraying was better controlled and levels remained below the relevant Occupational Exposure Limits throughout the study period. Urinary levels of cobalt and nickel mirrored the airborne concentrations and the highest urine concentrations were again found in plasma sprayers. Urinary chromium l evels were highest in electric are sprayers, which may also reflect an increased body burden in this group due to a longer history of exposu re. The findings clearly indicate that exposure to and uptake of metal s may exceed UK Occupational Limits or Standards when spraying is perf ormed manually or semi-automatically and where control relies on local exhaust ventilation (LEV) and personal respiratory protective equipme nt (RPE). (C) 1997 Elsevier Science B.V.