Tunnel workers engaged in the construction of multi-billion-dollar projects, including Brisbane’s Cross River Rail, Sydney’s Metro tunnels, and Melbourne’s Metro Tunnel, have been repeatedly exposed to crystalline silica dust at levels significantly exceeding regulatory limits.
Recent disclosures around silica dust levels in major infrastructure projects across the country show a persistent failure to comply with OHS standards, and confirm the concerns raised by the AWU and the CFMEU as we reported in our 2025 SafetyNet article.
Kate Cole, occupational hygienist and leading expert in workplace silica dust exposure, conducted analysis of hundreds of air sampling test results from the Cross River Rail project in Queensland. The data indicated that silica exposure breaches occurred at least fifty-five times, with one instance recording levels more than ten times above the permissible exposure limit.
These recent findings, resulting from leaked WorkSafe notices, Right to Information requests, and independent occupational hygiene analyses, indicate that systemic issues in monitoring, reporting, and enforcement have placed thousands of workers at severe risk of incurable respiratory diseases.
Major contractors push back on releasing data
Despite legal opposition from joint contractors including CPB, BAM, Ghella, and UGL, who argued against disclosure of the air sampling test results on the grounds of public interest and potential industrial unrest, the Queensland Civil and Administrative Tribunal ordered the release of the documents. However, the dataset ultimately released to Ms. Cole was incomplete, covering only the period up to March 2021, which is when tunnelling using the tunnel boring machine was just beginning. Also, Ms. Cole’s analysis has revealed that 44% of the monitoring reports she received were conducted during periods of low activity, restricted access, or suspended work, raising serious concerns about the accuracy and representativeness of the safety data provided to regulators.
Compliance issues not confined to Queensland
Similar patterns of non-compliance were identified in Victoria and New South Wales. Leaked notices from WorkSafe Victoria detailed breaches at the Melbourne Metro Tunnel project, where employees were exposed to silica levels up to ten times the standard. These exposure breaches were not communicated to supervisors or the affected workers until four months after detection.
In addition to engineering controls to suppress dust, underground workers usually wear masks to prevent them from inhaling the dust, but to be effective the PPE must be fit-tested and worn correctly, and workers must be clean-shaven for a proper seal. In several instances in the NSW tunnelling projects, workers were found wearing masks without being clean-shaven, a critical failure that compromises the efficacy of the PPE. Ms. Cole said the NSW reports also showed the ventilation in tunnels was not always adequate, and the effectiveness of ventilation was mainly assessed visually by a consultant rather than being measured.
Ms. Cole’s study of over 3,000 exposure figures across NSW tunnel projects found that roadhead operators without cabins were exposed to silica levels up to eighty times the workplace standard. The natural sandstone composition in NSW, containing over 90% crystalline silica, exacerbates these risks yet monitoring protocols have frequently failed to capture peak exposure events.
The health implications of such exposures are severe. Crystalline silica is an airborne hazard that, when inhaled, can cause silicosis, lung cancer, kidney disease, and chronic obstructive pulmonary disease. Silicosis is an irreversible and progressive condition with no cure. The long-term health consequences for affected workers are substantial, with legal representatives noting a growing number of diagnoses among tunnellers who have worked in high-risk environments for years.
Workers pressured to maintain production schedules
Industry critics argue that the primary driver of these safety failures is a corporate culture that prioritizes production schedules over worker health. Jonathan Walsh, a principal dust disease lawyer with Maurice Blackburn, reported that clients frequently described intense pressure to maintain progress, leading to situations where safety protocols were bypassed. There are allegations that regulators are occasionally directed to specific, low-dust sections of tunnels during inspections, while high-exposure activities continue elsewhere. This lack of transparency undermines the effectiveness of compliance checks and prevents timely intervention.
Although the Australian workplace exposure standard for silica was reduced to 0.05 mg/m³ in 2020, experts maintain that this threshold remains insufficient for the high-intensity conditions found in tunnelling work. Calls for stricter national standards and mandatory registration of high-risk silica workers have intensified following these revelations. Although government agencies assert that safety is a priority and that monitoring is compliant with regulatory obligations, the evidence suggests a dangerous gap between policy and practice, leaving tunnel workers exposed to critically high health risks.
The AWU and CFMEU encourage all members who have worked on tunnelling projects to contact their union for support and to access the supports available for lung screening, which vary from state to state.
Read more: Tunnel workers on major projects repeatedly exposed to excessive silica dust levels - ABC News