ABSTRACT
The workers on chemical plant are exposed to occupational hazards. Leakage of gases like chlorine produced as a byproduct in a soda ash plant, may cause airway damage. There may not be any clinical abnormality in respiratory system in early stages of exposure. Provocation with inhaled histamine in such workers may show an exaggerated response. This study was carried out to observe airway sensitivity pattern to inhaled histamine in workers exposed to chlorine leakage. STUDY DESIGN: Cross sectional. MATERIAL AND METHOD: Thirty workers on a chemical plant at 33 km on Sheikhupura Road, Faisalabad were selected as experimental and 30 asymptomatic adult from urban area of Lahore served as a control group. Forced vital capacity [FVC], Forced expiratory volume in first second [FEV1], forced expiratory flow at 25% of flow volume loop [FEF25], Mean Mid expiratory flow rate [FEF 25-75] and peak expiratory flow rate [PEFR] were measured before and after inhalation of maximum 8.00 [micro] moles of histamine diphosphate. PERIOD OF STUDY: July 1995-September 1995. Seven out of thirty [23.33%] mill workers had bronchial hyperresponsiveness [BHR] while in control group only one person exhibited BHR [3.38%]. There was a significantly more decrease [P<0.01] in FEV1, FVC, FEF25-75, FEF25 in chemical mill workers in comparison to controls. CONCLUSIONS: Our data shows that non-specific bronchial hyperresponsiveness can be present in asymptomatic subjects exposed to sensitizing agents like chlorine. Routine screening for BHR in such subjects is recommended to avoid development of chronic airway diseases and a longitudinal study should be carried out in order to evaluate this