Welding is a common industrial process with many millions of workers exposed worldwide. In October 2017, the International Agency for Research on Cancer (IARC) concluded that exposure to welding fumes causes lung cancer in humans, based primarily on the available epidemiological literature. These research studies did not show that the cancer risk differed between mild steel and stainless steel welding but were related to the total welding aerosol. Lung cancer risks were observable at very low exposure levels; below 1 mg m-3 and perhaps as low as 0.1 mg m-3, averaged over a working lifetime. As a result of this IARC evaluation, in Britain, the Health and Safety Executive has acted to strengthen its enforcement expectations for fume control at welding activities. In the light of these developments, it would seem appropriate to review current health-based exposure limits for metal dust and fumes from welding to ensure they are protective.