Acute respiratory effects of exposure to stainless steel and mild steel welding fumes

Over the past few years, many studies, including one on our previous work h ave examined the chronic effects of fumes from stainless steel (ss) welding on the health of welders. These chronic effects have been related to conce ntrations of chromium and nickel in SS welding fumes. The present study exa mined the acute respiratory effects of welding fumes in the workplace by me asuring the across-shift changes in a population of 144 SS and mild steel ( MS) welders and 223 controls. Manual Metal Arc, Metal Inert Gas, and Tungst en Inert Gas welding processes were studied. Pulmonary function tests were performed at the start (ante, or A) and at the end (post, or P) of the work Shift. The study of sensitization to harmful respiratory effects of-weldin g was based on the study of the (P - A)/A ratio (%) of the spirometric vari ations during the shift. The means of these ratios in the control subjects were used to account for the circadian effect. In SS welders we observed a significant decrease in forced vital capacity (FVC) during the shift. Signi ficant across-shift decrements in forced expiratory volume in 1 second (FEV 1) and FVC were related to the SS welding exposure compared with MS welding . Moreover, the across-shift decreases in FEV1, FVC, and peak expiratory fl ow (PEF) were significantly related to the Manual Metal Are welding process , compared with Metal Inert Gas techniques (respectively, PEF = -2.7% of ba seline values [SD, 11.9] vs 2.0% of baseline values [SD, 7.7] P = 0.04; FVC = - 1.5% of baseline values [SD, 4.8] vs 0.2% of baseline values [SD, 4.5] P = 005). We also demonstrated the influence of duration of SS welding exp osure on the course of lung function during the work shift. After 20 years of SS welding activity, SS welders had more significant across-shift decrea ses than MS welders with a similar MS exposure duration (respectively, FEV1 = - 2.7% of baseline values [SD, 5.9] vs 0.7% of baseline values [SD, 4.2] P = 0.008; PEF = -3.8% of baseline values [SD, 9.6] vs 2.3% of baseline va lues [SD, 6.5] P = 004). We concluded that welding-related lung function re sponses are seen in SS compared with MS welders and in those with a longer lifetime welding history.