CROSS-SECTIONAL ASSESSMENT OF WORKERS WITH REPEATED EXPOSURE TO CHLORINE OVER A 3 YEAR PERIOD

Airflow obstruction has been described in workers who experienced symp toms after acute exposure to chlorine. Persistent bronchial hyperrespo nsiveness has also been assessed, but mainly in case studies. In this cross-sectional study, we have assessed the relationship between inhal ational accidents (''puffs'') involving chlorine and persistent sympto ms as well as hyperresponsiveness in 239 out of 255 at-risk workers (9 4%). No relationship was found between persistent symptoms and the exp osure variables studied. Forced vital capacity (FVC) was higher in sub jects who had had no symptoms after a ''puff'', compared with those wh o had experienced mild symptoms. Forced expiratory volume in one secon d (FEV(1)) and FVC were significantly lower in subjects who experience d more than 10 puffs with mild symptoms than in subjects who reported no symptomatic puff. The presence of bronchial hyperresponsiveness was not related to exposure, but the methacholine dose-response slope sho wed a tendency to increased bronchial responsiveness with increased ex posure. A significant difference was shown in subjects who experienced more than 10 puffs with mild symptoms. In this group of workers, repe ated exposure to chlorine with acute respiratory symptoms was associat ed with a slight but significant reduction in expiratory flow rates, t ogether with an increase in bronchial responsiveness, without long-ter m symptoms.