Occupational asthma claims

Occupational asthma is one of the most common industrial lung diseases in the UK, and one of the most preventable. It develops when repeated exposure to a workplace sensitiser — a substance the immune system learns to react to — leaves the airways inflamed and twitchy. Once someone is sensitised, even tiny amounts can trigger wheezing, coughing, breathlessness and chest tightness, and continued exposure can make the condition permanent. Because employers have long known which substances cause it and how to control them, failing to do so can give rise to a claim.

What occupational asthma is

There are two broad patterns. Sensitiser-induced asthma develops after a period of exposure (sometimes months or years) during which the immune system becomes sensitised; thereafter, reactions can be triggered by very low levels. Irritant-induced asthma can follow a high-level exposure to a respiratory irritant. A tell-tale feature of occupational asthma is that symptoms often improve away from work — at weekends or on holiday — and flare again on return, a pattern that helps doctors and lawyers establish the link.

Common workplace triggers

The Health and Safety Executive recognises hundreds of respiratory sensitisers. The most frequently implicated include:

• Isocyanates — in spray paints, foams and coatings (vehicle body shops, manufacturing);
• Flour and grain dust — in bakeries, milling and food production;
• Wood dust — especially hardwoods, in joinery and furniture-making;
• Solder flux (colophony) — in electronics assembly;
• Latex — in healthcare and laboratories;
• Laboratory animals, enzymes and certain metals — in research, detergents and metalwork.

The employer’s duty

Under COSHH, employers must assess the risk from hazardous substances, prevent exposure where reasonably practicable, and otherwise control it — through enclosure, local exhaust ventilation, safe systems of work and, as a last resort, respiratory protective equipment that is properly fitted and maintained. They must also provide information and training and, for recognised sensitisers, health surveillance so early symptoms are detected. Diagnosed occupational asthma is also reportable to the HSE under RIDDOR. A claim generally arises where these controls were absent or inadequate and a worker developed asthma as a result.

Proving an occupational asthma claim

Medical causation is central. Evidence usually includes a respiratory expert’s report, supported by tests such as serial peak-flow measurements at and away from work and, where appropriate, specific challenge testing, plus your GP and occupational-health records. On the liability side, a claim is built from your exposure history and evidence of the employer’s failings under COSHH — no risk assessment, no ventilation, no health surveillance. Time limits run from your date of knowledge; see our time-limits guide.

How much an occupational asthma claim is worth

General damages are assessed against the Judicial College Guidelines chapter on lung disease. The bands below are illustrative ranges, not a valuation.

Source: Judicial College Guidelines, 17th edition (2024), lung disease chapter. Figures are illustrative; pre-settlement inflation may apply.

Worked example

Maria worked in a bakery for nine years with poor dust extraction and developed flour-dust asthma. Advised to avoid further exposure, she had to leave the trade. Her general damages are valued around £35,000 within the chronic bracket, and because she now earns less in a different role, a substantial future loss of earnings figure is added — often the largest single part of an occupational-asthma claim.

Frequently asked questions

Related guides: industrial disease claims, vibration white finger (HAVS), industrial deafness (NIHL), asbestos & mesothelioma, compensation calculator and all claim types.