Pulmonary function in granite dust exposure: a four-year follow-up.

Pulmonary function studies were performed on 974 workers in Vermont granite sheds in 1974. Of these subjects, 668 had been studied 4 years earlier and had remained in jobs in which their exposure to granite dust had not changed based on dust concentrations measured during 1970. The yearly decrement in pulmonary function observed in the 668 granite shed workers was excessive (0.07 to 0.08 liter per year for forced vital capacity and 0.05 to 0.07 liter per year for forced expiratory volume in 1 sec). This exceeded the expected decrement derived from several other occupational and population groups. Studies from this laboratory and published cross-sectional and longitudinal data consistently indicate a decrement of no more than 0.03 to 0.04 liter per year in both forced vital capacity and forced expiratory volume in 1 sec. The observed decrements were independent of exposure groups and not accounted for by cigarette smoking. In 528 additional granite shed workers, decrements in ventilatory capacity had been measured for one, 2, or 3 years and were consistently of the same order of magnitude. Dust concentrations within defined jobs and between granite sheds showed great variability. Despite this, a suggestive relationship between exposure and decrement in ventilatory function was demonstrated at the end of 2 years; however, at the end of 4 years the relationship could no longer be shown with these exposure groupings. The difficulty in characterizing individual dust exposures and projecting dust concentrations for several years is considered to account for the absence of a dose-response relationship at the 4-year follow-up. The results of this study suggest that our previous estimates of annual deterioration in ventilatory capacity attributable to work in granite sheds are underestimates. We conclude that present dust concentrations in Vermont granite sheds cause excessive deterioration of lung capacity. To prevent these effects, dust concentrations must be lowered.