Occupational Asthma

Occupational asthma is asthma that is caused by a substance inhaled at work. Although the contribution of workplace exposures to asthma may not always be clear, occupational asthma is considered to be the most common occupational lung disease.

Who is at risk?

Many different substances encountered at work can stimulate a hypersensitive response in a worker and cause asthma. Exposure in the workplace to a sensitiser substance such as certain chemicals, wood dust or animal antigens can cause a previously healthy worker to develop symptoms of asthma after a period of time.

What are the health effects?

The sensitiser substance can narrow the airway and reduce the air passage to the lungs. This is known as bronchial hyper-responsiveness due to workplace irritation. The sensitiser substance may have been previously tolerated by the worker and may not provoke that sort of reaction in others who are similarly exposed.

Tobacco smokers are at a bigger risk to occupational asthma than non-smokers. Some common sensitiser substances and groups of workers who may be exposed to them are:

 Sensitisers  Occupations
 Isocyanates  Spray painters, foam producers, insulation workers
 Animal antigens  People who work with laboratory animals
 Anhydrides Plastic  Industry workers
 Paper dust  Librarians, Bookkeepers, post office clerks
 Fluxes  People who work in the electronics industry
 Metals  Welders, metal plating workers
 Flour  Bakers, millers
 Wood dust  Carpenters, saw mill workers
 Drugs  Pharmaceutical workers

Symptoms of Occupational Asthma

Symptoms include coughing, shortness of breath, wheezing and a tight chest.

These symptoms occur during the working week, day by day, and improve during absences from work, at weekends or during holidays.

How to prevent Occupational Asthma

1. Provide information

There is sufficient knowledge available about occupational asthma to recognise and prevent the disease. Education in the workplace is important. Workers need to know about the disease and quickly identify any potential workplace causes for their symptoms.

Workers also need clear information about sensitiser substances and respiratory irritants encountered at work. Information on chemicals and other substances used at work should include any known sensitiser effects.

  • Control exposures at work

Workplaces can prevent occupational asthma by eliminating potential sensitisers or by minimising exposure to them. This will not only prevent workers from developing asthma from exposures at work but can also provide a safe work environment for those who have pre-existing asthma.

Some specific approaches that can be taken are:

  • Minimise exposure to dust particles, vapour or aerosol and to excessive cold or hot temperatures that can trigger occupational asthma.
  • If elimination is not possible, try to substitute with a substance that is not a known sensitiser.
  • Provide well-maintained ventilation systems to remove dust and other inhalable hazards.
  • Ensure that adequate facilities for personal hygiene are provided at work.
  • If exposures cannot be minimised, provide adequate protection to workers with suitable respiratory protective equipment.

Further information

The Asthma Foundation in each State and Territory provides information, resources, guidance and support to the community regarding asthma. A trained asthma adviser will answer specific queries (telephone 1800 645 130).

The Asthma Foundation of NSW can be contacted by phone on 02 9906 3233.

This Fact Sheet is courtesy of The Workers Health Centre.

More info:

Download the Occupational Asthma Fact Sheet

Sign up for updates