In 2018, the International Agency for Research on Cancer (IARC) classified welding fumes as “carcinogenic to humans”, an upgrade on its previous 1989 status as a “possible” cancer-causing agent.
Ultraviolet (UV) radiation from welding was also classified as carcinogenic, while molybdenum trioxide – a chemical sometimes used in welding – was classified as possibly carcinogenic by the IARC working group.
In particular, welding fumes and UV radiation have been identified as causing lung cancer and ocular (eye) melanoma, with the possibility of both also being linked to other cancers.
With an estimated 11 million welders worldwide and 110 million other workers who are likely exposed to welding activities, the need for safe practices to reduce the risk of disease is critical.
Welding fumes are produced when metals from the wire, electrode, base metal and metal coatings evaporate and then condense as a vapour.
The majority of fumes are usually particles of metallic oxides, silicates and fluorides, which can cause cancer.
Some common fume types include beryllium, cadmium oxides, chromium and nickel. Beryllium, cadmium and some forms of chromium and nickel are all known carcinogens.
The main factors which affect exposure to welding fumes include the welding process, type of metal, ventilation, degree of enclosure and use of personal protective equipment (PPE).
For example, stainless steel welding fumes can contain as much as 10 times more chromium and nickel than mild steel welding fumes, while manual metal arc welding of stainless steel produces a higher concentration of chromium fumes than gas metal arc or gas tungsten arc welding.