Increased respiratory cancer risk among Canadian electrolysis workers

The Cancer Registry of Norway has found, through examining Canadian and American reports from the period 1930-1992, an increase in cancer risk among electrolysis workers in the Canadian nickel industry. The results contrast sharply to statements from parts of the international nickel industry that maintain that no such risk is found in this group.

One of the first epidemiological studies of occupational cancer in Norway addressed respiratory cancer in nickel-refinery workers. The study was conducted and published by the Cancer Registry of Norway in 1973. Strongly increased risks of lung cancer and nasal (sinonasal) cancer were revealed among furnace workers as well as electrolysis workers. The latter group had been exposed mostly to water-soluble nickel compounds (soluble salts). In a recent review of U.S. and Canadian reports from the period 1930–1992, Cancer Registry researchers found similar risks among electrolysis workers in Canadian refineries. The results are in stark contrast to statements from parts of the international nickel industry, claiming that such risks have not been observed.

A Norwegian study from 1973 demonstrated a substantially increased risk of lung cancer and cancer of the ‘nose and nasal sinuses’ among Norwegian nickel-refinery workers. Similar risks had been found earlier in UK and Canadian workers, but the Norwegian study was the first to demonstrate clear evidence of excess in electrolysis workers, exposed mainly to water-soluble nickel compounds. Internationally, parts of the nickel industry have disputed the Norwegian results, and claimed that no risk has been found among Canadian electrolysis workers. To further elucidate the question, researchers Tom K Grimsrud and Aage Andersen at the national Cancer Registry reviewed mortality reports and technical data from the period 1930–1992. The results of their study were recently published in Scandinavian Journal of Work, Environment & Health.

Increased cancer mortality among Canadian electrolysis workers

Grimsrud and Andersen found evidence of increased mortality of lung cancer and nasal cancer among Canadian electrolysis workers exposed to water-soluble nickel compounds. The risk may be caused by inhalation of these chemicals. - Reports from the late 1970s have received little attention, said Tom Grimsrud. They might have been forgotten, or overshadowed by more recent studies, which since 1980 have been based on incomplete data. In addition, the analytical methods in later reports were rarely directed towards exploring effects from water-soluble nickel compounds.

Supports the IARC classification of nickel compounds as human carcinogens

In 1990 and 2009, the WHO International Agency for Research on Cancer (IARC) classified all nickel compounds as human carcinogens, inclusive of water-soluble salts, such as nickel sulphate and nickel chloride. Norwegian, British, and Finnish studies made this classification possible. - Our review of U.S. and Canadian reports lends support to the IARC classifications, said Tom Grimsrud.