Characterization of Lead Fume Exposure during Gas Metal Arc Welding on Carbon Steel

Abstract

This study was undertaken to determine if the welding fume generated during gas metal arc welding on carbon steel is a significant source of lead exposure to welders. Lead and total fume concentrations were determined for gas metal arc welding on three types of carbon steel. Lead concentrations between base metals were compared, and an attempt was made to generate a predictive model for lead concentration based on total welding fume.

Total fume concentrations ranged from 10 to 110 mg/m³ with a geometric mean of 31.6 mg/m³. Lead concentrations ranged from 1.0 to 17.6 μg/m³ with a geometric mean of 4.8 μg/m³. These lead concentrations were well below the Occupational Safety and Health Administration's permissible exposure level of 50 μg/m³. The 1018 steel produced significantly higher lead concentrations compared to the other base metals. It was not possible to generate a strong predictive model for lead concentration based on total fume.

This study indicated that the lead concentrations in the welding fume generated during gas metal arc welding on selected carbon steel were not significant. This would seem to support the contention that welding on bare steel is not a significant source of lead exposure to welders. However, additional research using additional carbon steel samples, including so called “recycled steel,” as well as other types of welding and base metal-electrode combinations is needed to confirm this. This study also pointed out the difficulty of trying to generate a model for predicting the concentration of incidental contaminants, like lead, from total fume concentrations.