Occupational Asthma: Your COSHH Duties

Is Occupational Asthma a COSHH Issue? (Short Answer)

Yes — squarely. Respiratory sensitisers are substances hazardous to health, so the full COSHH framework applies: assess the risk, prevent exposure where you can, control it where you cannot, and put exposed workers under health surveillance.

Three things make asthma different from most COSHH hazards, and they are the reasons employers get caught out:

Sensitisation is not dose-dependent in the usual way. Once a worker is sensitised, very small exposures can trigger an attack — including exposures that were previously harmless to them and remain harmless to everyone else.
Health surveillance is the expected default, not a judgement call, wherever people are exposed to an asthmagen.
A confirmed diagnosis is reportable to the enforcing authority without delay — not on the commonly-assumed fixed deadline.

Which Substances Cause It

HSE publishes a list of substances known to cause occupational asthma. The ones most likely to appear in an SME's chemical inventory:

Isocyanates — "Widely used in manufacture of polyurethane foams, plastics, coatings, varnish, two-pack paints and adhesives"
Alpha amylases — "Enzymes that change starch into sugar. Used in flour milling and bread baking. Also used in detergents, animal feed, textile processing and brewing"
Chromium (VI) compounds — "Compounds present in stainless steel welding fume and cement and used in electroplating"
Cobalt (metal and compounds) — "Present in the hard metal production and diamond polishing industries"
Latex — "Natural rubber latex is from the Hevea braziliensis tree. Health care workers are particularly susceptible through the use of latex gloves"
Chloramine-T — "A disinfectant with antiviral, bactericidal and fungicidal properties"
Cephalosporins and penicillins — antibiotics, relevant in pharmacy and veterinary settings
Carmine, castor bean dust, coffee bean dust, bromelains, azodicarbonamide — food, cosmetics, and polymer processing

Wood dust and flour dust are the other two that catch small employers regularly. If you run a bakery, a joinery, a body shop, a salon, a vet practice or a care setting, you almost certainly have an asthmagen on site.

The practical way to spot them on a data sheet is the hazard statement. H334 — "may cause allergy or asthma symptoms or breathing difficulties if inhaled" — is the marker for a respiratory sensitiser. Our guide to reading a safety data sheet covers where to look, and COSHH symbols and GHS labels explains the classification system behind it.

Your Control Duties

Nothing exotic here — it is the standard Regulation 7 duty, applied to a substance where the consequences of getting it wrong are permanent for the individual:

"Every employer shall ensure that the exposure of his employees to substances hazardous to health is either prevented or, where this is not reasonably practicable, adequately controlled."

HSE's advice to employers is direct about where to start: consider "substitution of harmful products with less harmful ones" before anything else. A water-based product instead of a two-pack, a pre-mixed compound instead of one that generates airborne dust, an alternative to latex gloves.

Where you cannot substitute, work down the hierarchy in the statutory order — engineering controls before protective equipment. HSE groups the controls it expects to be kept in good working order into three categories — mechanical controls (for example local exhaust ventilation and protective gloves), administrative controls (supervision), and operator controls (following instructions). In sensitiser work the engineering controls carry more weight than usual, precisely because the "safe" exposure level for a sensitised individual may be close to zero. See COSHH control measures, LEV testing, and — for the last resort — RPE and fit testing.

For substances carrying the H334 hazard statement — the ones on the list above — COSHH sets a higher bar than "adequately controlled". Regulation 7(7)(c)(ii) provides that control is only treated as adequate if "exposure is reduced to as low a level as is reasonably practicable" for a substance that carries H334, is listed in section C of HSE's "Asthmagen?" publication, or that a risk assessment has shown to be a potential cause of occupational asthma. That is the statutory basis for the "close to zero" standard above — staying under a workplace exposure limit is not enough for an asthmagen.

One thing worth stating plainly: relying on RPE as the primary control for a known asthmagen is a weak position. If a worker becomes sensitised while wearing a mask you selected instead of installing extraction, the question will be why the higher control was not reasonably practicable.

Health Surveillance Is the Default

Regulation 11 sets the duty:

"Where it is appropriate for the protection of the health of his employees who are, or are liable to be, exposed to a substance hazardous to health, the employer shall ensure that such employees are under suitable health surveillance."

"Appropriate" is where employers talk themselves out of it. For asthmagens, HSE removes the ambiguity:

"All employees exposed or likely to be exposed to an asthmagen should receive suitable health surveillance."

In practice that usually means a baseline respiratory questionnaire before or at the start of exposure, periodic questionnaires afterwards, and lung function testing where the risk justifies it — escalating to a doctor or occupational health professional when something is flagged. HSE notes the purpose plainly: "collecting simple information may lead to early detection of ill health caused by work and identify the need for improved control measures."

That second half matters. Surveillance is not only about the individual. A flagged case is evidence your controls are not working for everyone else still exposed.

Health records are long-lived. Regulation 11(3) requires the record be "kept available in a suitable form for at least 40 years from the date of the last entry made in it." That is a longer retention duty than most businesses' entire lifespan — worth designing for rather than discovering later. More in our health surveillance guide.

Reporting: The "Without Delay" Rule

This is the part most commonly stated wrongly, so it is worth going to the source.

Occupational asthma is a reportable disease under RIDDOR 2013. Regulation 8 lists it at (e):

"occupational asthma, where the person's work involves significant or regular exposure to a known respiratory sensitizer"

Two conditions have to be met before the duty bites. HSE: "A reportable disease must be diagnosed by a doctor" — and "Asthma is a common condition and is only reportable when the person's work involves significant or regular exposure to a known respiratory sensitiser." Ordinary asthma in a worker with no sensitiser exposure is not reportable.

Now the timing. You will often see "you have 10 days to report it." For a disease, that is wrong. Schedule 1, Part 1, paragraph 2(1) of RIDDOR 2013:

"the responsible person must send a report of the diagnosis in an approved manner to the relevant enforcing authority without delay."

Without delay — no fixed day count. The ten-day figure people remember comes from a different category of report altogether. If you have a written diagnosis of occupational asthma in a worker with significant sensitiser exposure, the report goes in now, not within a fortnight.

Records of the report must be kept — regulation 12 requires each entry in the record to be "kept for at least three years from the date on which it was made."

One caution if you are researching this yourself: older material online sometimes references "RIDDOR 1995". The current instrument is the Reporting of Injuries, Diseases and Dangerous Occurrences Regulations 2013 (SI 2013/1471). Work from the 2013 text.

When Someone Reports Symptoms

The sequence that keeps you compliant and, more importantly, stops the condition worsening:

Take it seriously immediately. Wheeze, cough, chest tightness or breathlessness that improves on days off or on holiday and returns at work is the classic pattern.
Remove or reduce exposure straight away while you investigate. Do not wait for a diagnosis to act.
Refer to occupational health or the worker's GP for diagnosis. Only a doctor's diagnosis triggers the RIDDOR duty.
Report without delay once diagnosed, if the sensitiser-exposure condition is met.
Review the COSHH assessment. Regulation 6(3) requires review "forthwith" where there is reason to suspect the assessment is no longer valid — a case of occupational asthma is exactly that.
Check everyone else who works with the same substance. One case means the control failed, not that one person was unlucky.
Fix the control, not just the case. Moving the affected worker without changing the exposure leaves the next person in the same position.

Occupational Asthma Checklist

Keeping the Surveillance Cycle Running

Health surveillance for sensitisers is a recurring obligation with a 40-year record tail, and it usually fails quietly — a questionnaire round that slips a year, a new starter who never got a baseline, a leaver whose record goes into a box.

COSHHmate is being built to link the substances you hold to the people exposed to them and the surveillance those exposures trigger, so a missed round surfaces as a gap rather than as a diagnosis. Pricing will be a flat monthly fee with no per-user charges. To get your COSHH health surveillance on a proper footing, join the waitlist.

Sources

This is general guidance based on the COSHH Regulations 2002, RIDDOR 2013 and published HSE guidance. Diagnosis of occupational asthma is a clinical matter for a doctor, and whether a particular exposure is "significant or regular" depends on the facts — take occupational health advice for your specific situation. Not medical or legal advice.