Sources Of Exposure

Given its many uses and applications, the potential for exposure to nickel, its compounds, and alloys is varied and wide ranging. With respect to occupational exposures, the main routes of toxicological relevance are inhalation and, to a lesser extent, skin contact.

Workers engaged in nickel production – which may include mining, milling, concentrating, smelting, converting, hydrometallurgical processes, refining, and other operations – are exposed to a variety of nickel minerals and compounds depending upon the type of ore mined and the processes used to produce intermediate and primary nickel products. Generally, exposures in the producing industry are to moderately soluble and insoluble forms of nickel. In the producing industry, soluble nickel compounds are more likely to be found in hydrometallurgical operations. Exposures in nickel-using industry sectors vary according to the products produced and include both soluble and relatively insoluble forms of nickel.

In the past, airborne occupational nickel concentrations were believed to have been quite high (>10 mg Ni/m3) in certain producing operations, with some estimates of exposures as high as 100 mg Ni/m3 or more for Ni3S2 sintering (sometimes referred to as “matte” sintering). More recent estimates of exposure (post-1960) are much lower, with current measurements generally averaging <1 mg Ni/m3. Exposures to nickel species in user industries have historically been much lower than in producing industries, with estimates generally averaging well below 1 mg Ni/m3.