Agricultural worker - common causes of asthma

Respiratory disease is a major occupational health risk for those working in agriculture, with an incidence of occupational asthma several times the national average. The most common cause of asthma amongst agricultural workers is as a result of exposure to agricultural dusts.

Agricultural dusts, such as grain dust and poultry dust, can be a complex mixture of organic and inorganic materials derived from fungal spores, bacteria, endotoxins, mites, animal dander and faeces, plant dust, soil, bedding, feed and feed components, chemicals, etc.

When the dust is inhaled it can trigger an allergic reaction in the respiratory system of some people. If this happens, any subsequent exposure, even to very small amounts, may produce symptoms. The symptoms of asthma are coughing, wheezing and chest tightness. Other associated conditions are runny or stuffy nose (rhinitis) and/or conjunctivitis (itchy and inflamed red eyes).

See COSHH Essentials - agriculture for agricultural workers for detailed advice on control.

Top tips

You should, wherever possible, avoid breathing in dust and spores by taking the following precautions:

  • Do not create more dust than necessary when working.
  • Ensure that machinery is constructed, adapted and maintained to contain dust as far as possible.
  • Where materials are handled indoors, make sure there is adequate ventilation – either local exhaust ventilation or dilution ventilation of the whole area. Get a competent person (eg a ventilation engineer) to confirm that it is adequate.
  • Observe good housekeeping where materials are being handled. Use an industrial vacuum cleaner to remove excess dust from the floors, walls and rafters of buildings. If you have to use a brush, thoroughly wet the dust beforehand to stop it from rising.
  • Keep personal clothing and hair clean, eg by wearing a coverall and headgear.
  • Use disposable protective clothing, otherwise ensure your working clothes are laundered regularly. Do not take them home with you – leave them at the workplace.
  • Where other methods of preventing exposure are not reasonably practicable, wear suitable, properly fitted and maintained respiratory protective equipment (RPE).
  • You need appropriate health surveillance.

If workers are exposed to grain, poultry or other agricultural dusts that contain asthmagens, then they should be under suitable health surveillance. You have a legal duty to do this as an employer. Decisions on the appropriate form of health surveillance may require the advice of an occupational health professional. The precise form of health surveillance will depend on the particular circumstances of exposure (level, frequency and duration) identified by the risk assessment.

Further information


You can find more guidance and information for agriculture workers on the asthma publications pages.

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