Respiratory morbidity in rubber workers: II. Pulmonary function in curing workers.

Pulmonary function tests were conducted on 121 curing and 189 control workers in 1972; 87% of the 1972 cohort was resurveyed one year later. The curing workers were subdivided into high and low exposure groups on the basis of environmental sampling. Cross-sectionally, in the 1972 cohort, the residual forced vital capacity was significantly decreased (P greater than .01) among the the heavily exposed workers (266 ml). Longitudinally, the mean one-year loss of forced expiratory volume in one second (FEV1.0) (173 ml/yr) in the curing workers with more than ten years of exposure was significantly greater (P less than .01) than in the control groups. Pulmonary function tests before and after a day's work were conducted on 29 curing-room workers. The eight heavily exposed curing workers had a significant decrease (P less than .05) in FEV1.0 of 115 ml. Our findings are sufficient to conclude that heavy exposure to curing fume affects pulmonary function. We recommend reduction of exposure and further longitudinal studies, especially in regard to those most heavily exposed.