8288298 Interventions to reduce exposure to welding fumes in gas metal arc welding at the workplace – Progress of the INTERWELD study

<h3>Objective</h3> Welding fumes have been classified carcinogenic to humans by IARC in 2018, but current OELs are not always met at welding workplaces. Practical solutions are needed to reduce welders’ exposure to hazardous substances. <h3>Material and Methods</h3> In an ongoing intervention study the effectiveness of technical measures to reduce exposure at real workplaces is evaluated. Repeated measurements of hazardous substances and biomonitoring (for chromium, nickel, and manganese) are carried out combined. Exposure determinants are comprehensively documented. <h3>Results</h3> So far, exposure was measured under baseline conditions in 53 welders, who applied gas metal arc welding (GMAW) in 13 companies. The median concentration of respirable particles was 1.38 mg/m³ in the welder’s breathing zone (measured in front of the welding hood). The German occupational exposure limit (OEL) for respirable particles (1.25 mg/m³) was exceeded at every second workplace. The highest concentration was 12 mg/m³. For respirable manganese (MnA), the German OEL (0.02 mg/m³) was exceeded at 50 of 53 workplaces (94%); with a median value of 0.10 mg/m³. At baseline 35 welders (66%) wore helmets with powered air purifying respirators (PAPR). The OEL for respirable manganese (MnA) was exceeded in 40% of the stationary fume measurements in the near field of the welding workplaces. The OEL for respirable particles was never exceeded here. <h3>Conclusion</h3> Compliance with the OEL during GMAW is a challenge. Personal protective equipment, such as PAPRs, is often required to ensure adequate health protection. The individual workplaces are currently being examined by expert teams for possible interventions. The focus is on the alloys of the welding wires, the mixture of process gases, innovative welding process variants and adjustments to local extraction systems. Once measures have been implemented, their effectiveness will be evaluated.