In brief
Occupational asthma is asthma that develops as a result of sensitisation to an agent at the workplace or intense exposure to an irritant; flour dust, isocyanates and some cleaning agents are the best-known triggers. The key to diagnosis is documenting with PEF measurements that symptoms increase on working days and decrease on days off. In a sensitised worker, the best outcome is achieved by stopping exposure early and completely.
What is occupational asthma, and how does it differ from work-aggravated asthma?
A master baker who has worked without problems for years starts coughing during dough-kneading hours and waking at night wheezing; yet during two weeks of annual leave he has hardly any complaints. This picture is a typical start of occupational asthma. Occupational asthma is asthma caused by an agent at the workplace and occurs in two main forms:
- Sensitiser-induced asthma: The worker is exposed to a substance for months or years and the immune system becomes sensitised to it. Once sensitisation has occurred, even very small amounts can trigger an attack. Flour, isocyanates and enzymes are in this group.
- Irritant-induced asthma: A single high exposure, for example to chlorine gas released from wrongly mixed cleaning chemicals, can leave permanent hyperresponsiveness in the airways.
Separate from these is work-aggravated asthma: the worker's pre-existing asthma worsens at work because of cold air, dust or fumes. The distinction matters, because in work-aggravated asthma reducing exposure is often enough, whereas in a sensitised worker continuing to work with the same agent makes the disease progress. The term work-related asthma is used to cover both situations together.
Main triggers: flour, isocyanates and cleaning agents
The table below summarises the respiratory sensitisation agents frequently found at businesses in Bursa and the surrounding provinces and where they occur.
| Agent | Where is it encountered? | Point to watch |
|---|---|---|
| Flour dust and flour additive enzymes | Bakeries, flour-based products, biscuit and pasta production | Emptying sacks, first start-up of the mixer, sprinkling flour on the bench |
| Isocyanates | Polyurethane paints and varnishes, foam, adhesives; automotive paint shops, furniture | Hardener component; aerosol during spraying, skin contact |
| Chlorinated and quaternary ammonium cleaning agents | Food plant sanitation, hospitals, cleaning services | Spray application, mixing with each other |
| Wood dusts | Furniture and joinery workshops | Sanding and cutting |
| Latex | Healthcare institutions | Powdered latex gloves |
| Persulphates | Hairdressing salons | Preparing hair bleaching powders |
| Rosin (colophony) fumes | Electronics assembly | Soldering |
| Acid anhydrides | Epoxy resin hardeners | Mixing and curing |
The quickest way to find out whether a product carries this risk is the safety data sheet. If section 2 contains the statement H334 ("May cause allergy or asthma symptoms or breathing difficulties if inhaled"), the product is a respiratory sensitiser. We explained what to look for in which section of the sheet in our article on how to read a safety data sheet. For booth and mask arrangements with isocyanate paints, see our article on paint booths and painter risks.
Symptoms: compare working days with days off
The symptoms of occupational asthma are no different from ordinary asthma: cough, wheezing, chest tightness and shortness of breath at work. They are often preceded by occupational rhinitis symptoms such as a runny nose, sneezing and itchy eyes. Taking this early warning seriously is the best opportunity to take measures before asthma becomes established.
What makes diagnosis difficult is that symptoms do not always appear at work. Some agents cause complaints hours after the shift, at night, and the worker does not link this to work. So the first question the workplace physician asks is: "Do your complaints ease at weekends, public holidays or during annual leave, and get worse when you return to work?"
Asking the worker to keep a simple symptom diary for two or three weeks makes the answer to this question concrete. Each day the diary records: the date, whether it is a working day or a day off, the shift, the work done that day (e.g. emptying flour sacks, preparing glaze), the severity of symptoms and medication used. This record is also the road map for subsequent measurements.
PEF monitoring and other tests in diagnosis
The most practical method of objectively showing the relationship between work and symptoms is serial PEF (peak expiratory flow) measurement with a peak flow meter. Art. 6/4-b of SGK's Regulation on Procedures for Determining the Rate of Loss of Working Capacity and Occupational Earning Capacity also requires, in a claim of occupational asthma, together with bronchial provocation and similar tests, PEF values measured four times a day for 15 days during a holiday period and for 20 days in the work environment. In other words, the comparison is the method provided by the legislation itself.
A fall in PEF values on working days or an increase in diurnal variation, with recovery during the leave period, supports occupational asthma. The physician may additionally request pre- and post-shift pulmonary function tests; the baseline value taken at the pre-employment examination is very valuable in this comparison. We explained how the test is interpreted in our article on the pulmonary function test (PFT). For agents such as flour and enzymes, skin prick tests or specific IgE are carried out, and where necessary a specific bronchial provocation test in specialist centres.
The workplace physician refers a case in which they have made a preliminary diagnosis of occupational disease to healthcare providers authorised by SGK (Art. 14/3 of Law No. 6331 on Occupational Health and Safety). When a diagnosis is made, the employer notifies SGK of the occupational disease reported to it within 3 working days of learning of it (Art. 14/2-b). For the whole process, see our article on what an occupational disease is, diagnosis and notification.
Ending exposure: the centre of treatment
Medication relieves symptoms; but if a sensitised worker continues to work with the same agent, the disease usually progresses. The best outcome is therefore achieved by stopping exposure early and completely. Merely reducing exposure or keeping the worker in the same job with a mask is not enough in most cases; a mask is not a long-term solution but a transitional measure.
In practice, this decision is carried out through these steps:
- Physician assessment: The workplace physician states in writing which jobs the worker can do. Health information is confidential; only the work restriction is passed on to the manager.
- Change of duties: The worker is moved to a department the agent does not reach, for example the dispatch department, where there is no flour dust, instead of the dough room. Under Art. 15 of Law 6331, a change of job also requires a health examination.
- Other workers: A single case is also a warning for other workers in the same department. Those exposed to the same agent are asked about symptoms.
- Renewing the risk assessment: Health surveillance results are among the reasons for renewing the risk assessment regardless of its validity period.
Prevention at source: what is done in bakeries and paint shops?
Baker's asthma is a preventable disease, and most of the measures are low-cost:
- Do not empty flour sacks by shaking them from a height; set up local exhaust ventilation or an enclosed emptying arrangement at the emptying point.
- Start the mixer with its lid closed and at low speed; add the flour to the bowl slowly.
- Do not sprinkle flour on the bench by throwing it into the air; keep your hand close to the bench.
- Do not use dry sweeping or compressed air for cleaning; use wet methods or a HEPA-filtered vacuum cleaner.
- Where possible, choose enzyme-containing additives in liquid or paste form rather than powder.
With isocyanate products, first check whether a system without isocyanates can be used. If you have to use them, spray in an extracted booth, use suitable respiratory protection and prevent skin contact with the hardener using gloves; sensitisation can also develop through the skin. With cleaning chemicals, do not mix products with each other, apply with a cloth rather than a spray where possible, and put the dilution instructions in writing.
A dust mask comes after these measures taken at source; for choosing the right class, see our article on FFP1, FFP2 and FFP3 dust masks. We plan the measurement of dust levels in the workplace with authorised laboratories and enter the results into the risk assessment.
How is health surveillance planned?
In occupational asthma, health surveillance aims to catch the disease early. At the pre-employment examination, the history of asthma and allergy is asked about, and if the physician considers it necessary, a baseline pulmonary function test is carried out. The frequency of periodic examinations depends on the hazard class: at least every 5 years in less hazardous, at least every 3 years in hazardous and every year in very hazardous workplaces. For example, bread making (10.71.02) is in the less hazardous class; however, the physician can shorten the interval for workers exposed to flour dust and apply an annual respiratory questionnaire in between. The pulmonary function test has no fixed frequency in the legislation; the physician decides according to the risk.
The 2026 base administrative fine for failing to provide health surveillance is 22,194 TL per employee. You can track examination and test dates with the OHS calendar. Bursa Sistemer OSGB plans tests with authorised healthcare institutions as part of its health surveillance and workplace physician services, and addresses flour dust exposure together with the risk assessment at businesses in the food sector. For other risks specific to bakeries and patisseries, see our article on OHS in bakeries and patisseries.
Frequently Asked Questions
Is a cough that improves at weekends a sign of occupational asthma?
On its own it does not establish a diagnosis, but it is an important clue. Symptoms increasing on working days and decreasing on days off are sufficient reason to see the workplace physician and start PEF monitoring.
Does baker's asthma go away?
If it is diagnosed early and exposure to flour dust is stopped completely, symptoms can decrease markedly. As long as exposure continues, the disease usually progresses; so the decision to change duties should not be delayed.
Can I continue in the same job wearing a mask?
For a sensitised worker a mask is not a permanent solution; even very small amounts can trigger an attack. The mask should be regarded as a temporary measure until a change of duties is made. The workplace physician makes the decision.
Who diagnoses occupational asthma?
The workplace physician makes the preliminary diagnosis and refers the worker to a healthcare provider authorised by SGK. The final diagnosis and occupational disease decision are made at the end of this process.
An exposure-based test plan, pre-employment and periodic examinations, confidential health files and an examination schedule tracked per person.
Bursa SİSTEMER OSGB Technical Team — written from the field experience of our OHS specialists and workplace physicians. Legal information is valid as of the publication/update date; contact us for an assessment specific to your business.