The prevalence of chronic obstructive pulmonary disease in chlorine gas workers.

The relationship between chronic chlorine gas inhalation and obstructive pulmonary disease was studied in 139 workers at risk in a chlorine gas plant. Chest roentgenograms, respiratory questionnaires, and ventilatory studies were obtained. The average chlorine concentration in the air was less than 1 part per million, but accidental additional exposure occurred in 55 workers and was severe enough to require oxygen therapy. Only 3 workers had significant impairment of ventilatory function. Radiographic appearance of the lungs and the questionnaires correlated poorly with abnormal ventilatory function. The immediate effect of acute chlorine exposure was an obstructive ventilatory defect that cleared rapidly. Smokers who were exposed to chlorine demonstrated decreased maximal midexpiratory flow.