Occupational Asthma Statistics UK: Cases, Causes & Rates (2026)

Work is thought to cause somewhere between 9% and 15% of adult-onset asthma in the UK, yet only a few dozen new cases are formally recorded each year. The key UK occupational asthma statistics — cases, causes and at-risk jobs — fully sourced.

Occupational asthma is a lung disease caused by breathing in a substance at work that the airways become sensitised to — most often isocyanates in vehicle paint, or flour and grain dust in bakeries. This page gathers the key UK statistics in one place: how many people it affects, which agents and jobs cause the most cases, and which way the numbers are moving. The figures come from HSE’s annual work-related asthma statistics, the THOR/SWORD chest-physician surveillance scheme run by the University of Manchester, and the DWP’s Industrial Injuries Disablement Benefit (IIDB) data.

Key facts and figures

• 9–15% of asthma in adults of working age is estimated to be caused by occupational factors.
• 7,500–9,000 new cases of work-related asthma a year are implied for Great Britain by a European incidence rate of 25–30 per 100,000 people.
• 52 new cases of occupational asthma were reported by chest physicians (THOR/SWORD) in 2024, down from 94 in 2023.
• 35 new occupational asthma cases were assessed for Industrial Injuries Disablement Benefit in 2024, against a ~73-a-year average across 2010–2019.
• 22,000 new self-reported cases a year of breathing or lung problems are believed caused or made worse by work (95% CI 14,000–30,000).
• Flour and isocyanates remain the two most commonly cited causal agents — together 5 of the 35 IIDB cases assessed in 2024.
• 40% of reported occupational asthma cases in 2020–2024 were in Skilled Trades Occupations, up from 34% in 2010–2019.
• ~3% a year — the modelled fall in occupational asthma incidence across 2010–2024.

These are the latest published figures available as of July 2026, and this page is updated when new data is released — HSE publishes its work-related asthma statistics annually as part of its autumn statistics cycle, alongside the wider occupational lung disease overview.

How many people get occupational asthma in the UK each year?

Occupational factors are estimated to account for 9–15% of adult-onset asthma in people of working age, according to the epidemiological studies HSE cites in its work-related asthma statistics. That framing matters, because it puts the true burden far above the handful of cases that reach formal recording. A European population-based study put work-related asthma incidence at 25–30 cases per 100,000 people per year, which is equivalent to roughly 7,500–9,000 new cases a year in Great Britain.

Set against those estimates, the numbers that specialists and the benefits system actually capture are strikingly small. Chest physicians reporting to THOR/SWORD recorded an estimated 52 new cases of occupational asthma in 2024, down from 94 in 2023. This is a substantial underestimate of the true incidence, because only cases that are referred to and reported by a consultant are counted — the great majority of workers with work-caused asthma are managed by GPs, are misdiagnosed as ordinary adult asthma, or never connect their symptoms to their job at all. HSE itself describes the specialist-reported figures as capturing only the tip of the iceberg.

What do the self-reported and benefit figures show?

An estimated 22,000 new cases a year of breathing or lung problems are believed to be caused or made worse by work (95% confidence interval 14,000–30,000), based on HSE’s Labour Force Survey averaged over 2022/23 to 2024/25. A substantial minority of those will be work-related asthma, though the self-reported survey does not split the diagnosis out precisely. The same survey estimates around 49,000 prevalent cases of work-related breathing or lung problems (95% CI 36,000–61,000) — a rate of roughly 140 per 100,000 workers, down from about 200 per 100,000 in the early 2000s.

On the benefits side, 35 new cases of occupational asthma were assessed for Industrial Injuries Disablement Benefit in 2024, up slightly from 30 in 2023 but well below the average of around 73 a year across 2010–2019. IIDB assessments count only workers who claim, whose asthma is one of the scheme’s prescribed forms of the disease, and whose assessed disablement is high enough to qualify — so, like the specialist figures, they sit far below the true incidence. Taken together, the self-reported, specialist and benefit measures triangulate the same picture: a large hidden burden, a small recorded one, and a long-run downward trend.

What is the most common cause of occupational asthma at work?

Flour and isocyanates remain the two most commonly cited causal agents for occupational asthma, both among chest physicians reporting to SWORD and in the IIDB caseload — the two agents together accounted for 5 of the 35 IIDB cases assessed in 2024. Isocyanates are the hardeners in two-pack vehicle paints and polyurethane foams and coatings; flour and grain dust drive the cases seen in bakeries and food manufacturing. Both are classic respiratory sensitisers: once a worker’s airways are sensitised, even very low exposures can trigger an attack, which is why HSE treats them as substances requiring exposure to be reduced as low as is reasonably practicable.

Beyond those two, the recognised list of asthmagens on this page’s lane runs to spray-paint and foam isocyanates, glutaraldehyde (used in disinfection and endoscopy), latex, colophony (rosin-based solder flux) and a range of reactive chemicals. Welding fume and metalworking-fluid mist also cause respiratory ill health, but the detail on those two agents sits on their own pages — see welding fume statistics and metalworking fluid statistics — and wood dust, which carries a separate sinonasal cancer risk, is covered on the wood dust statistics page. All of them are substances hazardous to health, so exposure must be assessed and controlled under COSHH; the supplier’s safety data sheet is where respiratory sensitisation hazards are flagged.

Which jobs have the highest risk of occupational asthma?

Vehicle paint technicians, bakers and flour confectioners, fishmongers and poultry dressers, and welding trades are the highest-incidence occupations for occupational asthma, on the 2010–2019 rates that remained the highest group in 2020–2024. The pattern maps directly onto the two dominant agents: spray painters are exposed to isocyanates, bakers to flour and grain dust.

The trade-level rates make the small-number caution unavoidable. Bakers and flour confectioners had an occupational-asthma incidence of 35.5 per 100,000 workers a year in 2010–2019, falling to 6.1 per 100,000 in 2020–2024 — but that fall is based on only around 12 versus 2 estimated cases a year, so year-to-year movement should be read with care. At the broad occupational-group level the picture is steadier: Skilled Trades Occupations made up 40% of reported occupational asthma cases in 2020–2024, up from 34% in 2010–2019, while Process, Plant and Machine Operatives fell to 19% (from 29%).

By industry, manufacturing has a substantially higher occupational-asthma rate than the all-industry average, with food-product, motor-vehicle, chemicals and basic-metals manufacture the highest-incidence sub-sectors on the 2010–2019 data that continued into 2020–2024. Again, each cluster reflects its dominant asthmagen: flour in food manufacture, isocyanates in motor-vehicle work, reactive chemicals in chemicals manufacture.

Who develops occupational asthma — and at what age?

Occupational asthma affects a wide age range, but the caseload skews towards older workers: in the THOR data, 18% of cases were aged 25–34, 17% aged 35–44, 26% aged 45–54 and 28% aged 55–64. That older-weighted profile fits a disease of cumulative exposure and delayed diagnosis — sensitisation can follow years of contact with an agent, and the gap between first symptoms and a specialist diagnosis can be long.

It is worth separating occupational asthma from the broader occupational lung disease caseload. In 2024, chest physicians recorded 473 new cases of occupational respiratory disease in SWORD, of which around 14% were shorter-latency conditions such as occupational asthma and hypersensitivity pneumonitis. The larger share of that total is made up of long-latency diseases whose death breakdown — mesothelioma, chronic obstructive pulmonary disease and silicosis — is covered on the COSHH statistics umbrella page rather than here. This page owns the asthma slice specifically.

Is occupational asthma rising or falling?

The University of Manchester statistical model estimates occupational asthma incidence fell by around 3% a year across 2010–2024 (a point estimate of -3.24%, 95% CI -5.63% to -0.78%). After adjusting for changes in reporting behaviour, the underlying incidence has been broadly constant since 2010, so most of the visible decline reflects a genuine reduction in new cases rather than a statistical artefact. That is consistent with the wider self-reported measure, where the rate of work-related breathing and lung problems has fallen from roughly 200 to 140 per 100,000 workers since the early 2000s.

The drivers are the same controls that prevent the disease in the first place: substitution of the worst asthmagens, better local exhaust ventilation and enclosure in spray booths and bakeries, respiratory protective equipment where residual exposure remains, and health surveillance that catches sensitisation early. None of that makes the problem solved — a fall in a preventable disease that still generates thousands of implied new cases a year is a reason to keep controls tight, not to relax them.

Is occupational asthma covered by COSHH, and what does it cost?

Yes — substances that cause occupational asthma are respiratory sensitisers and fall squarely within the COSHH Regulations 2002. Because asthma is one of the effects the regulations single out, exposure to a known asthmagen must be reduced as low as is reasonably practicable regardless of whether a workplace exposure limit exists, following the hierarchy of control — substitution and engineering controls before RPE — and backed by health surveillance for workers exposed to sensitisers. What substances trigger these duties is set out in what is covered by COSHH.

The economic burden is significant but the headline UK figure is dated. The most-cited estimate put the cost of occupational asthma in the UK at £70–100m, with around 49% borne by the individual, 48% by the state and only about 3% by the employer — but that comes from a 2011 study built on a 2003 cost base, so it should be read as a historical order-of-magnitude benchmark rather than a current figure. The striking feature that endures is the distribution: the worker and the taxpayer carry almost the entire cost of a disease the employer is best placed to prevent. Workers whose asthma was caused by their job may be able to claim IIDB, and the disease is reportable under RIDDOR where a doctor links it to a known workplace sensitiser.

Frequently asked questions

How many people get occupational asthma in the UK each year?

Formal recording captures only a fraction: chest physicians reported an estimated 52 new cases in 2024, and 35 were assessed for Industrial Injuries Disablement Benefit. The true incidence is far higher — occupational factors are thought to cause 9–15% of adult working-age asthma, and a European incidence rate of 25–30 per 100,000 implies roughly 7,500–9,000 new cases a year across Great Britain.

What is the most common cause of occupational asthma at work?

Flour and isocyanates are the two most commonly cited causal agents, both among chest physicians and in the benefits caseload — together they accounted for 5 of the 35 IIDB cases assessed in 2024. Isocyanates come from two-pack vehicle paints and polyurethane products; flour and grain dust drive the cases seen in bakeries and food manufacturing.

Which jobs have the highest risk of occupational asthma?

Vehicle paint technicians, bakers and flour confectioners, fishmongers and poultry dressers, and welding trades have the highest incidence rates. Skilled Trades Occupations accounted for 40% of reported cases in 2020–2024, and manufacturing — especially food-product, motor-vehicle, chemicals and basic-metals manufacture — sits well above the all-industry average.

Is occupational asthma covered by COSHH, and can you claim compensation?

Yes. Asthmagens are substances hazardous to health under COSHH, so employers must assess and control exposure and provide health surveillance for workers exposed to sensitisers. Occupational asthma is a prescribed disease for Industrial Injuries Disablement Benefit, payable where a worker’s asthma was caused by their job and their assessed disablement is high enough, and it is reportable under RIDDOR.

Related guides

• COSHH Statistics UK: Hazardous Substances at Work
• Welding Fume Statistics UK: Exposure & Lung Disease
• Metalworking Fluid Statistics UK: Mist & Respiratory Risk
• Wood Dust Statistics UK: Exposure, Asthma & Cancer
• What Substances Are Covered by COSHH? (And What Isn’t)

Sources & references

• HSE — Work-related asthma statistics in Great Britain (statistical summary, 2025 release)
• HSE — Occupational Lung Disease statistics in Great Britain (2025 release)
• HSE — Asthma: an overview of causes, at-risk occupations and the COSHH duty
• HSE — THORR04 data table: occupational asthma rates per 100,000 by occupation
• University of Manchester — THOR/SWORD: Surveillance of Work-related and Occupational Respiratory Disease
• DWP — Industrial Injuries Disablement Benefit quarterly statistics
• Asthma + Lung UK — national asthma context and economic burden
• Ayres et al. — Costs of occupational asthma in the UK, Thorax 2011 (historical, 2003 cost base)

Mark McShane

Health & Safety Training Specialist, Online CPD Academy

Mark writes about workplace health & safety, COSHH and accredited online training for COSHH Training, part of Online CPD Academy.