Studies of Respiratory Morbidity in Rubber Workers

Abstract

Pulmonary function tests, chest x-rays, and respiratory questionnaires were administered to eighty talc* workers and 189 non-exposed rubber workers from three rubber tire manufacturing plants. The talc workers, who were exposed to talc at levels below the current threshold limit value (TLV) of 20 mppcf for nonfibrous talc, had a statistically significantly greater prevalence of productive cough and of positive criteria for chronic obstructive lung disease (COLD) than did the control workers. The talc workers with more than 10 years of exposure had significantly decreased residual FEV_1.0. Multiple regression analysis of FEV_1.0 in the talc workers estimated that each year of exposure to talc dust reduced the FEV_1.0 by 26 ml. Talc workers had a clear increase in respiratory morbidity, despite the absence of chest roentgenographic changes. Based on this study, a safe exposure level for talc appears to be 25 mg/m³ as a time-weighted average.

Throughout this paper, the talc referred to is industrial grade talc.