Pulmonary functions of welders in gas transmission pipelines in Iran.

This study evaluated the influence of welding on pulmonary functions in welders. Spirometry tests were performed before and after work shift in 91 welders and 25 clerks (control group). We examined forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1), FEV1/FVC ratio and forced expiratory flow 25%-75% (FEF 25-75). Significant differences were found for FVC and FEV1/FVC between welders and the control group in pre- and post-shift measurements (p < .001). In welders, smoking and nonsmoking habit had no significant effects on any pulmonary indices before or after shift. Work experience and fume concentrations also had no significant effects on the majority of spirometric indices (p > .05). Most welders had at least 1 of the respiratory symptoms. Significant differences were found between pre- and post-shift indices (as percentage of predicted values calculated with spirometer) and between the welders engaged in some welding tasks and the control group before work shift. This study documented work-related changes in pulmonary functions in the welders and marked drops in these functions without symptoms in some welders.