A guide to Occupational Asthma

Occupational asthma is a lung condition caused by exposure to inhaled irritants in the workplace. This type of asthma can be developed working in a range of industry sectors. As an employer, it is your legal responsibility to protect workers from this risk.

Employees suffering with occupational asthma often have trouble identifying the origin of their symptoms. This means that suffering workers frequently fail to seek treatment, continuing their exposure to the harmful trigger.

All substances that are known to cause occupational asthma are within the classification of substances hazardous to health as set out by the Control of Substances Hazardous to Health Regulations 2002 (COSHH), which must be observed by employers at all times.



Causes of Asthma in the Workplace

According to HSE, more than 250 causative substances have been identified. This comprehensive list includes:

  • Laboratory animal excreta / secreta, mainly from rodents, other small mammals or insects
  • Chemicals used in paint, varnish, printing inks, hydraulic fluids, nylon, plastics and cosmetics
  • Enzymes used in bread baking and flour milling, as well as textile manufacturing and brewing
  • Metals, particularly chromium, cobalt and nickel sulphate
  • Plant substances, including proteins found in rubber latex, cereals, flour, cotton, flax, hemp, rye and wheat
  • Respiratory irritants, such as chlorine gas, sulphur dioxide and smoke

Inhalation of any of the above substances can lead to occupational asthma or aggravate a pre-existing asthmatic condition.


Symptoms of Occupational Asthma

Asthma is a debilitating condition for which 5.4 million people in the UK are currently receiving treatment.

The main symptom of occupational asthma is shortness of breath. This can prevent a person from performing the simplest of tasks and can often mean they are unable to work to their full potential, if at all, as a result.

Other symptoms include:

  • Wheezing
  • Coughing
  • Chest tightness

Symptoms can develop immediately after exposure to a workplace substance or several hours later, often worsening at night. Eye irritation, nasal congestion, or runny nose may also be present. If exposure to the substance ceases completely, the condition is likely to improve.

In many cases, occupational asthma is entirely reversible within the first two years of development. Despite this, continued exposure to harmful triggers will cause the condition to worsen, lowering the chances of a full recovery.

Identifying a case of occupational asthma as early as possible is therefore of fundamental importance and health surveillance is consequently a requirement.

The ability to promptly identify cases of occupational asthma, should therefore be a priority to employers in maintaining the required standard of health and safety.

When a trigger of occupational asthma is identified, employers must ensure that all members of staff are protected. Necessary protections include:

  • Wearing suitable RPE
  • Improved control of harmful substance
  • Substituting harmful substances with something else
  • Employee is moved to a different role within the company.




How to Mitigate the Risk of Asthma Developing in the Workplace

To mitigate the risk of occupational asthma, employers must recognise the numerous triggers that exist in their workplace. It is the employer’s responsibility to understand the risks regarding aggravated asthma, and to implement suitable protections for the benefit of their employees.

Where materials and substances that cause asthma in the workplace are present, employers are advised to provide the following:

  • An up-to-date health and safety policy
  • Health surveillance
  • Information to employees
  • A risk assessment
  • Adequate control measures

Although carrying out a risk assessment is the responsibility of the employer, it is always advisable to consult an occupational hygienist, such as ourselves, as best practice. Workplace Exposure can carry out COSHH air monitoring in your workplace in order to gather the necessary information to perform the risk assessment, as well as recommend practical ways to improve the air environment.


How to Prevent Exposure to Possible Causes of Occupational Asthma

Should the risk assessment determine that workers are being exposed to known causes of occupational asthma, the following control measures should be considered:

  • Replace the substance with a safer alternative where possible
  • Isolate the work in order to minimise the number of workers exposed
  • Enclose the process as much as possible
  • Provide local exhaust ventilation
  • Provide appropriate respiratory protective equipment (RPE) to workers, such as filtering devices or breathing apparatus

Whilst respiratory protection equipment (RPE) reduces the number of new cases of occupational asthma, it does not completely prevent the disease and so should never be the primary means of controlling exposure.



Even brief removal of RPE can cause development of occupational asthma emphasising the importance of consistent supervision.

Employers must ensure that when protective equipment is worn, the appropriate type is used and maintained, fit testing is performed and workers know how to wear, remove and replace it.

Where risk of exposure remains – despite the implementation of control measures, health surveillance must also be provided.

Health surveillance is a system of ongoing health checks that, depending on the situation, take the form of medical assessments, annual respiratory questionnaires or lung function tests. Our health and safety consultancy service provides employers with a suitable programme of health surveillance in the workplace.



Occupational asthma is preventable. This guidance has outlined the simple but effective measures that an employer should implement to prevent and control exposure to all known triggers.

The principal method of prevention is to reduce exposure at the source. Thereafter, employers must perform health surveillance to identify early symptoms and refer any workers suspected to be suffering for further tests.

The likelihood of symptoms improving or disappearing is greatest for those who have no further exposure to the causative substance. Therefore, early diagnosis and early avoidance of ongoing exposure – either by substitution of the hazard or by redeployment of the worker – offer the best chance of full recovery.

At Workplace Exposure, we support employers in their efforts to protect employees, visitors and customers from exposure to harmful substances.We also offer professional solutions and advice regarding issues of Health and Safety. Do not hesitate to get in touch with us today.


Our approach

Get in touch with Workplace Exposure. Either give us a call on 0800 689 4386, or fill in our enquiry form to discuss your monitoring or consultancy requirements.

We’ll then provide you with a no-obligation proposal, we can often give an initial idea of fees whilst we discuss your needs.

Once you’ve accepted our proposal, we can then schedule the work.

Following our site visit we’ll provide you with a comprehensive report giving you advice, recommendations and control measures where appropriate. Implement the outcomes for compliance and a happier healthier workplace.