Welding Fume in Manufacturing

Metal Inert Gas (MIG) and Flux-Cored Arc Welding (FCAW) are the dominant processes in manufacturing fabrication workshops. FCAW in particular generates high fume emission rates due to the flux decomposition. Workshop environments with multiple welding bays operating simultaneously create cumulative background fume levels that affect all workers in the space, not just the welders themselves.

Welding stainless steel by any process generates hexavalent chromium Cr(VI) in the fume. Cr(VI) has a WES of 0.05 mg/m³ TWA and is a confirmed lung carcinogen and respiratory sensitiser. TIG welding on stainless steel generates lower total fume mass but a higher percentage of Cr(VI) relative to total fume. Separate filter cassettes are required for Cr(VI) analysis to prevent reduction to Cr(III) during storage.

Mild steel welding fume contains manganese at 5-15% of total fume mass. The WES for manganese is 1 mg/m³ TWA inhalable fraction. Chronic overexposure causes manganism, a progressive neurotoxic condition. Manufacturing welders performing full-shift welding on mild steel are at elevated risk of exceeding the manganese WES even when total fume levels appear moderate.

Fabrication of tanks, vessels, hoppers, and large assemblies requires welders to work inside or partially inside the structure. Fume concentrations inside semi-enclosed fabrications can be 5 to 10 times higher than open workshop levels. Portable LEV or on-torch extraction must be assessed for effectiveness in these configurations.

Typical Worker Groups

Common similar exposure groups (SEGs) assessed for this sub-category.

Regulatory Context

Safe Work Australia published the Welding Processes Code of Practice in 2019 following the IARC Group 1 reclassification of welding fume. The code requires all welding fume to be captured at source or controlled to below the WES using engineering controls as the primary measure, with RPE as supplementary only. From 1 December 2026, the WES for welding fume (not otherwise specified) reduces from 5 mg/m³ to 1 mg/m³ inhalable fraction. Health monitoring is required for workers with significant welding fume exposure, including respiratory function testing and a medical assessment by a registered medical practitioner with experience in occupational health. The WHS Regulation also requires health monitoring for hexavalent chromium under Schedule 14.