By Kate Cole OAM
Kate Cole OAM is a certified occupational hygienist dedicated to preventing work-related disease. With expertise in silicosis prevention, her work is shaped by a Winston Churchill Fellowship and experience on major construction and tunnelling projects worldwide. A past President of the Australian Institute of Occupational Hygienists, she serves on the NSW Dust Diseases Board, the Asbestos and Silica Safety Eradication Council, and other key committees. For her contributions to workplace health and safety, she received the Medal (OAM) of the Order of Australia and was in include in the COVID-19 honour roll in the 2022 Australia Day Honours. Kate now works as an independent consultant while completing her PhD research on respirable crystalline silica exposures to tunnel construction workers.
The silicosis crisis in the engineered stone industry has sent shockwaves across Australia. We’ve seen the faces of young workers grappling with incurable lung disease, families reeling from sudden diagnoses, and an entire trade brought to its knees—culminating in a nationwide ban.
But as the dust settles in one sector, another industry is only just beginning to reckon with its own hidden danger: tunnelling.
Just like stonemasonry, tunnel construction involves cutting and grinding silica-rich materials. And just like the engineered stone sector, tunnelling has operated for years without visibility of the health risks faced by workers. The difference is that the danger in tunnelling has remained largely hidden—until now.
In a recent study published in the Annals of Work Exposures and Health, my colleagues and I analysed personal exposure monitoring data collected during three major Australian tunnelling projects. Our aim was to assess how much respirable crystalline silica (RCS) workers were exposed to and what that meant for their long-term health. We estimated one in ten tunnel workers were expected to develop silicosis over their lifetime from working on those projects.
The risk is real, and it is already translating into cases. Workers in tunnel construction are being diagnosed with silicosis.
Silicosis is entirely preventable. We know what causes it, we know how to control it, and we have had that knowledge for decades. What is missing is implementation—and consistency in that implementation.
Just like other safety hazards, preventing silica-related disease is best done through applying the hierarchy of control. That means starting at elimination and doing everything else first other than PPE, which we consider the last line of defence.
Applying the hierarchy of control for RCS looks like this:
Elimination: The most effective way to manage RCS is to remove the source entirely. Practical examples: Review design specifications early in the planning stage to identify whether silica-containing materials can be avoided altogether. If that’s not possible, then plan ahead to prevent the need to actually cut into silica-containing materials like concrete to eliminate the generation of dust.
Substitution: When elimination is not possible, the next step is to substitute hazardous materials or tasks with safer alternatives. Practical examples are using materials with a lower silica content, such as low-silica cement or grout, or using the product in its wet form (e.g. pre-mixed concrete).
Engineering Controls: These are physical measures that reduce exposure by containing, removing, or preventing the release of RCS. This can include things like ventilation systems, partial enclosures, or automating dusty tasks to keep workers away from the hazard. Practical examples include:
- Using wet cutting or core drilling methods instead of dry cutting to suppress dust at the source.
- Installing on-tool dust extraction systems that are compliant with Australian Standards and maintaining them regularly.
- Fitting cabins on plant and equipment with pressurised, filtered air supply as per AS/ISO 23875.
- Using local exhaust ventilation or extraction booths in enclosed or semi-enclosed spaces.
Administrative Controls: These controls reduce the duration, frequency, or intensity of exposure by modifying the way work is performed. Practical examples are rotating workers to reduce individual exposure times, particularly during high dust activities; and restricting access to areas where dust-generating activities are occurring.
Personal Protective Equipment (PPE): Respiratory protection should only be used when other controls cannot reduce exposure to acceptable levels, or as a short-term interim measure. Respiratory protection needs to match the exposure level and task type (e.g. P2 or P3 filters, half, full face or powered air purifying respirator for example). There are also many other tasks that need to happen when respiratory protection is used. For example, workers will need to undergo fit testing at least annually, and whenever a new respirator model is introduced if the respirator requires a seal around the face (such as a ‘dust mask’, half or full face respirator). Storage and maintenance facilities will also be needed, and workers must be provided training in their correct use.
One of the most consistent themes in poor exposure control is that measures are inconsistently applied. Controls might be implemented at the start, but are not maintained during regular operations. To reduce exposure effectively, controls must be embedded into work procedures and treated as non-negotiable components of safe work systems.
This also includes integrating air monitoring by occupational hygienists into routine operations. Personal sampling should be used to validate whether current controls are performing as intended, and to identify any high exposures that may require additional risk reduction strategies.
The recent data from Australian tunnelling projects provides an evidence base that should inform broader construction safety practices. Other high-risk tasks in civil and commercial construction, such as jackhammering, concrete cutting, drilling, and grinding, require similar controls and oversight.
Silicosis is not a mystery—it’s a known hazard with known solutions. What’s needed now is resolve. By embedding the hierarchy of safety control into the way work is done —from planning to execution—we can stop history from repeating itself.
