14/04/2022

Recognising the carcinogenic nature of work involving exposure to welding fumes

In France, more than 528,000 employees are potentially exposed to welding fumes. According to the latest available data, inhaling these fumes containing metal particles can cause lung and throat cancer. Following its expert appraisal, ANSES thus recommends including work involving exposure to welding fumes and metal fumes from related processes in the Order listing carcinogenic substances, mixtures and processes as defined in the French Labour Code.

Many workers are exposed

According to the 2017 SUMER survey conducted by the Ministry of Labour, 528,000, that is 2.1% of all French employees, are exposed to welding fumes containing metallic elements. Welders are not the only workers affected. Many other workers may be exposed to fumes during their careers even if welding is not their main occupation. The industry sectors concerned are construction, installation and repair of machinery and equipment, vehicle repair and metalworking.

Carcinogenic welding fumes

In 2018, the International Agency for Research on Cancer (IARC) classified welding fumes as “carcinogenic to humans” (Group 1) based on sufficient evidence in humans for lung cancer and limited evidence for kidney cancer.

Subsequent studies now conclude that there is sufficient evidence for throat cancer and limited evidence for mouth and sinonasal cancers.

The fume composition and amount produced depends on many parameters

Welding fumes consist of a gas phase and a particulate phase, which may contain carcinogenic metal particles.

The fume composition and amount produced during welding vary according to many parameters, including the composition of the parts welded, the filler materials and types of processes used, the melting temperature of the filler metal, etc. Related processes such as brazing, gouging, oxygen cutting, thermal spraying and hardfacing also release fumes with a similar composition to welding fumes.

Classifying work involving exposure to welding fumes and metal fumes from related processes as carcinogenic processes in accordance with the Labour Code

Given that it is not possible to establish which welding processes are associated with which types of cancer risk, the Agency recommends including all work exposing workers to welding fumes or metal fumes from related processes in the list of carcinogenic substances, mixtures and processes as defined by the Labour Code. “With this recommendation, besides workers exposed to welding fumes, we also suggest including workers exposed to metal fumes from related processes found to contain similar carcinogenic substances to welding fumes. This recommendation also applies to workers who do some welding even though they are not specialist welders, as well as workers who are passively exposed by being in the vicinity of people carrying out welding,” says Dominique Brunet, head of the ANSES Unit for Assessment of Chemical Reference Values and Risks.

Raising awareness among workers and improving knowledge

To prevent these cancer risks, the Agency stresses the importance of awareness raising and protecting workers directly or indirectly exposed to carcinogenic fumes. “To achieve this, employers and employees must be trained about using the most appropriate processes producing the smallest amount possible of fumes for the welding job in question. Capturing fumes at the source and monitoring exposure should also be implemented,” says Dominique Brunet.

More generally, ANSES recommends collecting more data on the various cancer risks besides lung and throat cancer that are potentially associated with these welding processes and for which the evidence is currently limited or inconclusive.

Finally, as well as exposing workers to fumes, the Agency points out that welding work also produces UV radiation classified as “carcinogenic to humans” (Group 1) by the IARC, which must be taken into account for the protection of exposed workers.