Characterization of exposures among cemented tungsten carbide workers. Part II: Assessment of surface contamination and skin exposures to cobalt, chromium and nickel.
Cobalt, chromium and nickel are among the most commonly encountered contact allergens in the workplace, all used in the production of cemented tungsten carbides (CTC). Exposures to these metal-containing dusts are frequently associated with skin sensitization and/or development of occupational asthma. The objectives of this study were to assess the levels of cobalt, chromium and nickel on work surfaces and on workers' skin in three CTC production facilities. At least one worker in each of 26 work areas (among all facilities) provided hand and neck wipe samples. Wipe samples were also collected from work surfaces frequently contacted by the 41 participating workers. Results indicated that all surfaces in all work areas were contaminated with cobalt and nickel, with geometric means (GMs) ranging from 4.1 to 3057 microg/100 cm(2) and 1.1-185 microg/100 cm(2), respectively; most surfaces were contaminated with chromium (GM=0.36-67 microg/100 cm(2)). The highest GM levels of all metals were found on control panels, containers and hand tools, whereas lowest levels were on office and telecommunication equipment. The highest GM levels of cobalt and nickel on skin were observed among workers in the powder-handling facility (hands: 388 and 24 microg; necks: 55 and 6 microg, respectively). Levels of chromium on workers' skin were generally low among all facilities. Geometric standard deviations associated with surface and skin wipe measurements among work areas were highly variable. Exposure assessment indicated widespread contamination of multiple sensitizing metals in these three facilities, suggesting potential transfer of contaminants from surfaces to skin. Specific action, including improved housekeeping and training workers on appropriate use and care of personal protective equipment, should be implemented to reduce pathways of skin exposure. Epidemiologic studies of associated adverse health effects will likely require more biologically relevant exposure metrics to improve the ability to detect exposure-response relationships.
Division of Respiratory Disease Studies, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, Morgantown, West Virginia 26505-2888, USA. GDay@cdc.gov
Gregory A
GA
Day
M Abbas
MA
Virji
Aleksandr B
AB
Stefaniak
D002857:Chromium / Q000633:toxicity*; D003035:Cobalt / Q000633:toxicity*; D009532:Nickel / Q000633:toxicity*; D016273:Occupational Exposure; D017973:Tungsten Compounds / Q000633:toxicity*
D017973:Tungsten Compounds; D002857:Chromium; C002802:tungsten carbide; D003035:Cobalt; D009532:Nickel