The Welding Institute

The IIW Releases a Statement on Lung Cancer and Arc Welding

8 Apr 2021 8:47 AM | Anonymous

A new statement has recently been released by the International Institute of Welding (IIW) regarding lung cancer and arc welding.

The statement was produced by the IIW Commission VIII, ‘Health, Safety and Environment,’ which is chaired by TWI Technology Manager and Member of The Welding Institute, Eur Ing Geoff Melton (SenMWeldI CEng). Commission VIII studies occurrences during the welding process that can potentially affect health, safety and the environment, and additionally looks at the development of technical guidance for correct management of the fabrication process in industry. Commission VIII acts as the global interdisciplinary forum for exchange of knowledge in the industry, supported by the expertise of its members who represent different scientific disciplines including Medicine, Chemistry, Occupation Hygiene and Welding Engineering.

The IIW is the world’s largest network and centre of reference for welding and allied joining technologies. Its mission is, ‘to act as the worldwide network for knowledge exchange of joining technologies to improve the global quality of life.’ The IIW’s mission also involves operating as the global body for the science and application of joining technology by providing a forum for networking and knowledge exchange among scientists, researchers and industry. Read more...

The International Agency for Research on Cancer (IARC) published Monograph 118, in 2018 where it outlined that welding fumes were evaluated and reclassified as Group 1 (carcinogenic to humans). Prior to this assessment, an IARC evaluation from 1990 classified welding fumes as ‘possibly carcinogenic’ to humans (Group 2B). The 2018 reclassification was therefore based on the epidemiological excess risk for lung cancer and the suppressive effect on the immune system caused by welding fumes.

Read the full IIW statement of lung cancer and welding below:


Assessment of the International Agency for Research on Cancer (IARC)

Monograph 118, 2018

In 2018, IARC published Monograph 118, in which welding fumes were evaluated, and has reclassified them as Group 1 (carcinogenic to humans). Based on this assessment, IARC revised its evaluation from 1990, when it classified welding fumes as “possibly carcinogenic” to humans (group 2B).

This assessment was based on an epidemiological excess risk for lung cancer and was supported by publications on local and systemic inflammatory processes and a suppressive effect on the immune system caused by welding fumes.


In 2003, IIW Commission VIII issued a statement on the excess risk of lung cancer in electric arc welders. In 2011, this statement was reconfirmed (Ref. Welding in the World, 55, 12-20, 2011).

IIW recommended that to eliminate the excess risk of lung cancer, welders and their managers must ensure that:

  • Exposure to welding fumes is minimised, at least to national guidelines,
  • There is no further exposure of welders to asbestos, and
  • Welders are encouraged and assisted not to smoke tobacco.

Since 2011, more human studies have been published. On the balance of evidence, the grade of risk excess has been confirmed. This assessment has been corroborated also in a meta-analysis published subsequently after the IARC monograph 118 (Honaryar et al. 2019). Again, the excess risk has been shown irrespective of the type of steel (mild steel or stainless steel) welded.

In addition to lung cancer, IARC stated that there is also an excess risk for kidney cell cancer, as shown in several epidemiological studies. The evidence was rated “limited” due to the fact that any confounding effect of solvents could not be ruled out.

IARC also classified ultraviolet radiation from arc welding as carcinogenic (sufficient evidence, group 1), based on an excess risk of uveal melanoma of welders found in some epidemiological studies.

Therefore, based on the current state of knowledge, IIW confirms its statement from 2011 and encourages all those responsible to reduce the exposure to welding fume to a minimum.

IIW recommends that to eliminate the excess risk of lung cancer, welders and their managers must ensure that exposure to welding fume is minimized, at least to national guidelines.

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