Respiratory cancer among copper smelter workers: recent mortality statistics.

A survey of mortality among copper smelter workers in the western United States revealed that a respiratory cancer excess previously observed during the period 1938 through 1963 continued from 1964 through 1977. When analyzed in relation to smelter employment prior to 1964, the recent increase in respiratory cancer was linked to work in plant areas where airborne arsenic concentrations were elevated and to a cumulative arsenic exposure index, although some excess risk was also associated with long-term employment in jobs with limited exposures to arsenic. The arsenic-related excess remained after adjustment for work in areas of the plant with elevated concentrations of sulphur dioxide, which was not found to have an independent influence upon cancer risk. Increased rates for nonmalignant respiratory disease were also observed, but were not significantly associated with arsenic exposure.