Asthma is a distressing and potentially life threatening disease. Each year up to 3,000 people develop asthma following exposure to dangerous substances at work. This is a disturbing figure, since almost all cases of occupational asthma could be prevented. Developing asthma following exposure at work is called ‘occupational asthma’.

The substances causing asthma are called respiratory sensitisers' or asthmagens. Sensitisation can occur after weeks, months or even years of breathing in the harmful substances, depending on the person and the substance. If a lung becomes hypersensitive to a sensitiser, even low exposure to the substance can trigger an asthma attack. During an asthma attack, the airways of the lung become narrowed and cause an obstruction to the flow of air.

Substances known to cause asthma​

  • Wood dust​

  • Epoxy resins in some glues and resins​

  • Isocyanates

  • Dust from latex rubber

  • Formaldehyde in some MDF (medium density fireboard)

  • Some paints and wood preservatives


Symptoms to watch for in yourself and the people you work with are coughing, wheezing, tightness of the chest, sneezing and a runny nose as well as itchy and inflamed red eyes. 
The symptoms can show directly after the exposure but also several hours later, which makes it more difficult to establish a link with workplace activities.

Employers’ duties

According to the Control of Substances Hazardous to Health Regulations (COSHH) employers are legally obliged to prevent or adequately control the exposure to sensitisers in the workplace.

Employers must inform, instruct and train employees who are likely to be exposed to respiratory sensitisersEmployers must also assess the risks that the exposure to the substances creates. If substances are in place, employers must prevent or adequately control the exposure by the following means:

  • Attempts must be made to stop using the sentisitiser altogether by replacing it with a different substance.
  • If this is not reasonably practicable, they have to segregate the work or totally enclose the process.
  • If not possible, they should partially enclose the process and provide local exhaust ventilation.
  • If after that measure adequate control can still not be guaranteed, employees need to use respiratory protective equipment (RPE).
  • Often a combination of all these measures will need to be applied. Unless it is guaranteed that all risks are controlled, also a system of regular health surveillance needs to be put in place.
  • If you are still worried, contact your UCATT Safety Rep or your Regional UCATT office.

Compensation payments

If you have developed asthma following exposure at work, you should tell your GP as well as your manager or safety officer, and ask that it gets recorded in the workplace accident book. Contact your UCATT Safety Rep or Regional Office, as UCATT could help you making a claim for compensation. In case you decide to take legal action against your employer, your lawyer must act within three years of you being diagnosed.

Further information

HSE Website:
TUC website:

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