HSE’s updated model attributes about 140 lung cancer deaths a year in Great Britain to welding, averaged over 2020–2024. All welding fume can cause lung cancer, including fume from mild steel.
IARC classified welding fume as carcinogenic to humans in 2017. HSE strengthened its enforcement expectations in February 2019 and requires suitable controls for all welding work, however occasional. This guide separates modelled cancer burden, published workforce estimates and practical exposure-control requirements.
Key facts and figures
- 200,000 people welding in the UK is IOM’s published approximate estimate, including about 40% professional welders; it is not a new workforce census.
- 140 estimated annual lung cancer deaths attributable to welding in Great Britain, average 2020–2024, in HSE’s updated model.
- Group 1 — in 2017 IARC reclassified all welding fume, mild steel included, as a definite human carcinogen, up from Group 2B.
- 175 annual cancer registrations attributed to welding in older research for 2004; a historical estimate, not a current count.
- +48% — occupational welding-fume exposure raises trachea, bronchus and lung cancer risk (pooled RR 1.48) in the WHO/ILO meta-analysis.
- 40–50 annual hospital admissions from breathing metal fume at work are estimated in HSE guidance; not a dated 2026 surveillance count.
- 0.05 mg/m³ is the respirable manganese workplace exposure limit — highly likely to be exceeded during uncontrolled welding.
- Feb 2019 — HSE requires exposure control (LEV and/or RPE) for all indoor welding, because there is no known safe level.
Checked on 15 October 2026. HSE’s updated cancer-death model uses the 2020–2024 average. The workforce and acute-illness figures are published approximate estimates without a current census year; older cancer registrations are explicitly historical.
How many welders are there in the UK?
IOM publishes an approximate UK estimate of 200,000 people who weld, about 40% professionally and the remainder as part of another job. The page does not establish a new 2026 census. Maintenance, fabrication, farming and vehicle work can all involve occasional welding, which still requires assessment and suitable controls.
IARC’s 2017 evaluation cited an estimated 11 million welders worldwide and about 110 million additional workers with welding-related exposure. These are global background estimates from that evaluation, not current UK employment counts. They also cover different definitions of welding work.
How many people die from welding fume in the UK?
HSE’s updated CAN02 table estimates 140 lung cancer deaths a year attributable to welding in Great Britain, averaged over 2020–2024. It applies historical attributable fractions to newer cancer statistics. The older study estimated 152 deaths in 2005 and about 175 registrations in 2004; those historical figures should not be presented as today’s measured annual toll.
Welding fume is generated by the work, so a COSHH assessment must consider it even where no supplied product carries a relevant label. The need for controls follows the hazard and exposure, rather than a ranking among occupational cancer causes.
HSE guidance estimates 40–50 welders a year are hospitalised after breathing metal fume and around 2 die from pneumonia. These are broad guidance estimates without a current annual reporting period. Vaccination may reduce pneumococcal risk for relevant workers but does not replace effective fume control.
Is mild steel welding fume a carcinogen?
In 2017 IARC evaluated welding fume as carcinogenic to humans, Group 1, with sufficient evidence for lung cancer. The classification covers welding fume generally, including mild steel; its earlier classification had been Group 2B. This is a statement about the evidence of hazard, not a measure of the risk from a particular exposure level.
IARC went further on two related exposures. It classified the ultraviolet radiation from welding as a Group 1 carcinogen as well — a cause of ocular melanoma (melanoma of the eye) — and it noted the evidence linking welding fume to kidney cancer. The upshot is that mild steel welding, long treated as the “safe” end of the trade, carries a confirmed cancer risk of its own.
The independent epidemiology backs the classification up. The WHO/ILO Joint Estimates meta-analysis found that any or high occupational exposure to welding fume raised the incidence of trachea, bronchus and lung cancer by around 48% (pooled relative risk 1.48, 95% confidence interval 1.29–1.70), across 23 studies (Loomis et al., Environment International, 2022). A relative risk of 1.48 means welders in these studies were roughly one-and-a-half times as likely to develop lung cancer as comparable non-exposed workers.
A point of scope worth being clear about: the hexavalent chromium and nickel in stainless-steel fume are carcinogens in their own right, but the cancer risk described here applies to the fume as a whole, mild steel included. Cr(VI) as a substance across all its exposure routes is a topic of its own and is not covered on this page.
Welding fume statistics at a glance
The table separates updated modelled deaths, historical research and approximate figures published in guidance.
| Measure | Latest figure | Period / source |
|---|---|---|
| Welders in the UK | ~200,000 (~40% professional) | IOM published estimate; census year not specified |
| Lung cancer deaths attributed to welding (GB) | 140 a year | Average 2020–2024, HSE model |
| Cancer registrations attributed to welding (GB) | About 175 a year | Historical 2004 estimate, published 2012 |
| Earlier estimated welding-related lung cancer deaths | 152 | Historical 2005 estimate, published 2012 |
| Increase in lung cancer risk from exposure | +48% (RR 1.48, 23 studies) | WHO/ILO Joint Estimates, 2022 |
| Hospital admissions after breathing metal fume | 40–50 a year | HSE guidance estimate; annual period unspecified |
| Deaths from pneumonia in welders | ~2 a year | HSE guidance estimate; annual period unspecified |
| Respirable manganese workplace exposure limit | 0.05 mg/m³ (8-hour TWA) | Current, HSE EH40 |
| IARC classification of welding fume | Group 1 (definite carcinogen) | 2017 evaluation |
What is metal-fume fever, and how common is it?
HSE estimates 40–50 hospital admissions a year after welders breathe metal fume and around 2 pneumonia deaths. These are guidance estimates, not counts of metal-fume fever alone. Metal-fume fever can cause flu-like symptoms after welding or hot work, particularly on galvanised metal. Symptoms following exposure should prompt medical advice and a review of controls.
Do not use flu-like symptoms as a diagnostic test or assume a brief illness is harmless. Other welding-related conditions, including pneumonia and irritant effects, may need treatment. Review exposure controls after symptoms, but absence of symptoms does not demonstrate that carcinogenic fume is adequately controlled.
What is the exposure limit for welding fume?
There is no single workplace exposure limit (WEL) for “welding fume” as a whole; instead the fume is controlled through the limits on its individual components and, since 2019, through a blanket HSE enforcement expectation. The most quoted component limit is for respirable manganese, set at 0.05 mg/m³ as an 8-hour time-weighted average in HSE’s EH40 — a level HSE warns is highly likely to be exceeded during uncontrolled welding. Manganese is present in the fume from ordinary mild-steel welding and, at excessive exposure, is linked to neurological (Parkinson-like) effects as well as respiratory harm.
Reduce exposure as low as reasonably practicable and meet any applicable component WELs. Consider avoiding or reducing welding first, then extraction at source for indoor work. Provide suitable RPE where extraction alone is inadequate or cannot reasonably be provided, and for outdoor welding where extraction is ineffective. Protect other people nearby as well as the welder.
What does HSE require for welding fume?
Since February 2019, HSE has required suitable exposure control — LEV and/or RPE — for all welding carried out indoors, regardless of duration, and expects effective control for outdoor welding too (HSE safety bulletin STSU1-2019). The change followed the IARC reclassification and reflects a simple conclusion: general ventilation alone does not achieve adequate control of welding fume, and there is no known safe level of exposure. In HSE’s words, the enforcement expectation applies whatever the material being welded and however brief the job.
A short weld is not exempt from assessment or suitable control. HSE’s current guidance prioritises avoiding or reducing exposure, then LEV for indoor work, with suitable RPE where necessary. The assessment must consider the material, process, duration, working environment and other people exposed; it should not treat a respirator as an automatic substitute for practicable extraction.
How does welding fit the wider lung-disease picture?
Welding is one thread in a much larger tapestry of work-related respiratory harm. HSE estimates that around 11,000 lung-disease deaths each year in Great Britain are linked to past workplace exposures across all agents — of which roughly 35% are chronic obstructive pulmonary disease (COPD), 23% non-asbestos lung cancer, 20% asbestos-related lung cancer and 20% mesothelioma (HSE Occupational Lung Disease statistics, published 20 November 2025). Separately, around 22,000 new cases a year of breathing or lung problems are self-reported as caused or made worse by work (Labour Force Survey three-year average, 2022/23–2024/25).
The updated estimate of 140 welding-related lung cancer deaths belongs within the wider modelled burden of harm from past exposure. It should not be added to the respiratory total as a separate category or interpreted as the number of current welders dying each year. The practical implication is to control fume whenever welding takes place.
Frequently asked questions
How many welders are there in the UK?
IOM publishes an approximate estimate of 200,000 people who weld in the UK, about 40% professionally. The figure includes welding as one task within another job and is not identified as a new 2026 workforce census.
How many people die from welding fume exposure in the UK each year?
HSE’s updated model attributes about 140 annual lung cancer deaths in Great Britain to welding, averaged over 2020–2024. It uses historical attributable fractions with newer mortality data. HSE separately publishes an approximate estimate of 2 pneumonia deaths a year among welders; this is not a current annual surveillance count.
Is mild steel welding fume a carcinogen?
Yes. In 2017 IARC reclassified all welding fume, mild steel included, as a Group 1 (definite) human carcinogen that causes lung cancer — upgrading it from the Group 2B rating it had held since 1989. There is no known safe level of exposure.
What is the workplace exposure limit (WEL) for welding fume?
There is no single WEL for welding fume as a whole; it is controlled through limits on its components and a blanket HSE enforcement expectation. The most quoted component limit is respirable manganese at 0.05 mg/m³ (8-hour TWA), which HSE says is highly likely to be exceeded during uncontrolled welding. As a carcinogen, welding fume must be controlled as low as reasonably practicable.
Do I need fume extraction for a quick mild steel weld?
A short weld still needs suitable controls. HSE recommends avoiding or reducing exposure first and using LEV indoors. Suitable RPE is required where LEV alone is inadequate or cannot reasonably be provided, and for outdoor welding where LEV is ineffective. Select controls for the actual task.
Related guides
- COSHH Statistics UK: Hazardous Substances at Work
- Silica Dust Statistics UK: Exposure, Silicosis & Deaths
- Occupational Asthma Statistics UK: Work-Related Lung Disease
- What Substances Are Covered by COSHH? (And What Isn’t)
- The COSHH Hierarchy of Control: How to Choose Controls in the Right Order
Sources & references
- HSE CAN02: estimated annual cancer deaths, average 2020–2024
- HSE CAN03: estimated annual cancer registrations, average 2018–2022
- HSE CAN01A: cancer burden model and methodological notes
- HSE: health risks from welding
- HSE: controlling welding fume
- HSE: welding fume safety alert, 2019
- HSE: Occupational lung disease statistics, 2025
- HSE-funded researchers: historical respiratory cancer burden, published 2012
- IARC: welding fume evaluation, 2017
- IOM: approximate UK welding workforce estimate
- WHO/ILO systematic review: welding fumes and lung cancer, 2022
- HSE EH40: workplace exposure limits
Welding fume is a COSHH carcinogen — make sure your team can recognise the risk and apply the right controls before the arc strikes.
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Mark writes about workplace health & safety, COSHH and accredited online training for COSHH Training, part of Online CPD Academy.