Employers in Australia have a legal obligation to ensure a safe working environment for all employees. This includes the identification and management of risks associated with occupational asthma, a condition that is both preventable and often under-recognised. Occupational asthma can result in serious health consequences for workers and significant legal and financial implications for organisations that fail to act. Effective management requires collaboration between employers, Occupational and Environmental Physicians (OEPs), and, in many cases, Occupational Hygienists to assess and address environmental triggers in the workplace.
Occupational asthma isn’t just a health issue. It can also present a productivity and safety risk. By identifying triggers early, implementing health surveillance programs, and seeking specialist support, employers can better safeguard their workforce and meet their duty of care.
Understanding Occupational Asthma
Work-related asthma (WRA) encompasses two main types: occupational asthma and work-exacerbated asthma.
Occupational asthma refers to new-onset or recurring asthma directly caused by exposure to a substance in the workplace. Work-exacerbated asthma involves the worsening of pre-existing asthma due to occupational factors such as dust, cold air, or physical exertion. While the clinical features of both conditions can be similar, accurate differentiation requires a detailed history and often specialist evaluation.
Occupational asthma can be further categorised into:
- Sensitiser-induced asthma, which involves a latency period and results from repeated exposure to substances such as flour, animal proteins, or isocyanates.
- Irritant-induced asthma, where symptoms develop within hours of a single high-level exposure to irritants like chlorine or ammonia.
According to the National Asthma Council Australia, over 90 per cent of occupational asthma cases are sensitiser-induced. Workers in industries such as food production, cleaning, construction, and healthcare are particularly at risk.
Causes and Risk Factors
Occupational asthma can be triggered by exposure to hundreds of known substances, with more being identified regularly. Common causes include:
- Inhaled allergens such as flour dust, animal dander, and plant proteins
- Chemical agents such as isocyanates, solvents, and chlorine
- Environmental conditions like extreme cold or high physical exertion
- Aerosols and fumes commonly encountered in manufacturing and industrial settings
Risk factors that increase susceptibility include:
- A personal or family history of allergies or asthma
- Smoking, which increases airway sensitivity
- Prolonged or repeated exposure to asthma-causing agents
Workers in high-risk jobs, including bakers, cleaners, welders, and animal handlers, are more likely to develop symptoms due to the nature of their occupational exposures.
Recognising Symptoms of Occupational Asthma
Symptoms may develop gradually, making early recognition difficult. Typical signs include:
- Persistent coughing
- Wheezing
- Chest tightness
- Shortness of breath
- Increased use of asthma reliever medications
A key feature of occupational asthma is a temporal pattern. This means that symptoms often worsen during the workweek and improve over weekends or holidays. However, in long-standing cases, this fluctuation may no longer be noticeable. Early identification is critical to prevent long-term damage and reduce reliance on high-dose medications.
Case studies, such as that of an 18-year-old bakery worker who developed symptoms within months of exposure to flour dust, illustrate how seemingly minor tasks can contribute to the onset of asthma. In this case, nasal and eye symptoms were followed by chest tightness and wheezing, which improved slightly during days off, but returned quickly upon re-entering the workplace.
Diagnosis and Medical Assessment
Accurate diagnosis of occupational asthma is complex and should be undertaken while the employee is still in the same role, ideally before any exposure is removed. The first step is confirming the diagnosis of asthma through objective tests.
Recommended diagnostic steps include:
- Spirometry testing to measure lung function
- Peak flow monitoring at and away from work to identify variability in symptoms
- Bronchial provocation testing, when needed
- Allergy testing for specific sensitisers
- A thorough occupational history, including materials handled, exposure duration, and use of protective equipment
Workplace visits or consultations with an Occupational Hygienist may also be required to assess actual exposure levels. Material Safety Data Sheets (MSDS) can help identify chemical components involved in workplace tasks. Referral to a respiratory or occupational medicine specialist is advised for further investigation and confirmation.
Managing Occupational Asthma in the Workplace
Effective management of occupational asthma requires a combination of clinical, environmental, and organisational interventions.
Identification and control of hazardous substances should be prioritised. Employers should:
- Conduct regular risk assessments to identify potential triggers
- Substitute high-risk substances with safer alternatives where feasible
- Improve local exhaust ventilation and air filtration systems
- Provide properly fitted respiratory protective equipment where necessary
Implementing health surveillance programmes can support early detection. Regular screening of at-risk employees and ongoing monitoring helps prevent irreversible damage and supports evidence-based decisions for work adjustments.
Medical management includes:
- Specialist referral for diagnosis and treatment planning
- Modifying work tasks or environments to reduce exposure
- Ensuring consistent communication between treating physicians, employers, and occupational health teams
Statistical Insight
Occupational asthma is under-reported in Australia. While the Australian Institute of Health and Welfare estimates that 9–15 per cent of adult-onset asthma is related to occupational exposure, only around 70 compensation claims are reported annually. This disparity highlights a significant gap in recognition, diagnosis, and reporting.
A cross-sectional study in New South Wales found that occupational exposures accounted for 9.5 per cent of adult-onset asthma. Internationally, this figure is likely closer to 15 per cent. Based on this data, there may be between 1,800 and 3,000 new cases of occupational asthma annually among working-age Australians.
The Australian Work Exposures Study found that 47 per cent of male workers and 40 per cent of female workers were likely exposed to one or more asthmagens in their jobs. High-risk occupations include farming, animal care, cleaning, and food processing.
The disparity between actual prevalence and reported compensation cases points to systemic barriers in diagnosis and reporting. These include patients’ reluctance to report symptoms, fear of job loss, and limited enquiry by clinicians into work-related exposures. This gap increases the risk of ongoing exposure, decline in lung function, and the development of preventable disease in other workers.
Treatment and Long-Term Outlook
Asthma management should follow best-practice guidelines, with inhaled corticosteroids and bronchodilators used as needed. However, treatment alone is not sufficient if exposure continues.
For irritant-induced asthma or work-exacerbated asthma, employees may continue in their roles if workplace modifications are made. This could include:
- Improved ventilation
- Substitution of less harmful substances
- Use of appropriate respiratory protection
For sensitiser-induced asthma, the most effective strategy is complete avoidance of the sensitising agent. In some cases, this may require removing the worker from the exposure environment entirely. However, the ideal solution is to remove the sensitiser from the workplace, thereby protecting both the affected worker and their colleagues.
All management plans should involve open communication between treating doctors, the employer, occupational health professionals, and compensation bodies where applicable. Early intervention improves long-term outcomes and minimises the likelihood of permanent disability.
Employer Responsibilities and Best-Practice Management
Employers have both legal and ethical obligations to minimise exposure to airborne contaminants. Failure to act may result in compensation claims, regulatory penalties, reputational harm, and workforce disruptions.
Occupational asthma management requires input from occupational physicians and, where appropriate, Occupational Hygienists to identify exposure sources and implement controls.
Proactive employers benefit through:
- Reduced absenteeism and staff turnover
- Improved worker morale and trust
- Reduced legal liability and exposure to claims
Neglecting workplace asthma risks can lead to increased costs, compliance issues, and long-term health burdens for workers.
Prevention Strategies for Employers
Preventing occupational asthma begins with:
- Identifying and substituting high-risk substances with safer alternatives
- Implementing regular screening and health surveillance for early detection
- Training employees on respiratory hazards and early symptom reporting
- Establishing systems to evaluate and respond to workplace exposures
- Consulting with occupational health professionals for tailored risk mitigation strategies
Phoenix Occupational Medicine offers health surveillance, telemedicine, as well as occupational and environmental consulting services to help employers meet their obligations and support employee respiratory health.
Key Takeaways
Occupational asthma is a preventable but often overlooked condition in Australian workplaces. Employers play a central role in identifying and managing risk factors and supporting early diagnosis and treatment. Proactive action can prevent long-term health consequences, reduce workplace disruption, and support regulatory compliance.
Phoenix Occupational Medicine provides expert guidance to employers looking to prevent and manage occupational asthma through best-practice health strategies, surveillance, and tailored advice.
To learn more or seek support for your workplace, contact Phoenix Occupational Medicine.
*Information provided is general only and should not be construed as legal or medical advice. We recommend that readers seek advice for their specific circumstances.
