Objectives The possibility was investigated that exposure to welding fumes causes an acute decrease in pulmonary function.

Methods Changes in the pulmonary function of 62 current welders and 75 nonwelders at the same sites and the relationship with work-related symptoms were recorded.

Results Work-related cough was reported by 22.6% of the current welders and 6.7% of the nonwelders [odds ratio (OR) 4.1, 95% confidence interval (95% CI) 1.5--11.5], and the respective figures for at least 1 work-related symptom were 30.7% and 16.0% (OR 2.3, 95% CI 1.0--5.2). The groups' preshift lung function did not differ. The mean percentage change from the base-line value of the forced expiratory volume in 1 s (FEV_1.0) after 15 minutes of work was -2.8% (range -29.3% to +20.9%) for the current welders and +1.0% (range -20.7% to +22.6%) for the nonwelders (P=0.01). A multivariate analysis identified current welding as the most significant risk factor for a decrease of at least 5% in FEV_1.0 after 15 minutes, the risk being greater for those with no local exhaust ventilation (OR 22.4, 95% CI 4.5--113.4) than for those with personal protection only (OR 16.0, 95% CI 2.1--122.9) and those with local exhaust ventilation (OR 2.8, 95% CI 0.2--41.2) or passive exposure only (OR 2.0, 95% CI 0.5--8.8).

Conclusions An acute decrease in FEV_1.0 in relation to work is more prevalent among welders than among nonwelders, and is more common among welders without local exhaust ventilation than among those with it.

Key terms pulmonary function; welding fume