Lung function among employees of a copper mine smelter: lack of effect of chronic sulfur dioxide exposure.

Lung function among 599 white male employees of a southeastern Tennessee copper mine/smelter operation was compared according to smoking history and occupational experience. The job categories compared included employees with work histories in low sulfur dioxide [SO2] environments (both underground mining and non-mining), in high SO2 exposure work areas, and in those with transient exposure to SO2. Miners with low SO2 exposure were found to have lower lung function indices (both FVC AND FEV1) than did employees in other job categories. Smoking history was strongly associated with low FEV1. After adjusting for smoking history, cumulative long-term exposure to SO2 was not demonstrated to contribute to decreased lung function.