ECHA has published a scoping study report on the evaluation of limit values for welding fumes and fumes from other processes that generate fume in a similar way at the workplace.
When heat is applied, the metals (in the base and filler materials) are vapourised and their vapours rapidly condense into very fine particles. Some misconceptions exist about the content/composition of welding fumes. They are often described simply as metals and their oxides, but in reality the fume particulates are complex structures (spinels) with other substances present in the fillers. The interaction between these spinels can also be complex and difficult to predict as they can inhibit each other’s effect or have synergistic effects.
Process generated and complex compositions
As welding fumes are process-generated, complex and have variable compositions, welding fumes as such do not have a harmonised classification and labelling for carcinogenic or other hazards under the CLP Regulation. The European Commission requested ECHA to evaluate, in accordance with the CMRD, “welding fumes+”: to assess and define the scope of these process generated substances of mixed and varying composition to allow for a description of the relevant processes, or sub-processes, to be included in Annex I of CMRD to ensure legal certainty of inclusion within the scope of the directive.