Revealed: The Sydney tunnel projects where deadly dust levels hit 208 times legal limit

Workers on Sydney’s transport mega-projects have been breathing in deadly levels of crystalline silica dust with alarming frequency as figures reveal one in three air-quality tests during construction of the Metro City and Southwest exceeded legal limits.

Transport for NSW air-quality tests between 2016 and 2020 during metro construction showed the highest unprotected exposure to the deadly dust was 208 times above the workplace safety standard. Of 948 tests in the City and Southwest tunnels, workplace standards were breached in 34 per cent of cases, including 8 per cent in which workers were unprotected.

Despite the health implications, SafeWork NSW has blocked the release of further air-quality results in other tunnels, including the $25 billion Metro West, siding with companies concerned about reputational damage.

WestConnex staff during tunnel construction in 2021.Credit: Kate Geraghty

The four years of data released to the Australian Workers’ Union (AWU) under freedom-of-information laws underscore the threat to the thousands of workers employed across transport projects.

Underneath Sydney, huge machines are burrowing through sandstone and shale, and the high silica content in the rocks poses risks for thousands of workers.

The Dust of Death investigation by The Sydney Morning Herald, The Age and 60 Minutes last year outlined the serious health risks for tradespeople working with engineered stone, which can contain up to 95 per cent crystalline silica. The revelations led the Commonwealth and state governments to ban manufactured stone benchtops, panels and slabs containing at least 1 per cent silica.

Research from Curtin University in 2022 predicted more than 10,000 Australians would develop lung cancer and up to 103,000 would develop silicosis after being exposed to silica dust at work.

The new data offers the first snapshot of the potential scale of exposure in the tunnelling industry, with nine mega-projects in NSW alone.

The air-quality data from sites overseen predominantly by John Holland Group and CPB Contractors reveals workers were repeatedly exposed to levels of silica dust above the Workplace Exposure Standard (WES) of 0.1 milligrams per cubic metre (mg/m3). This threshold was halved in July 2020, near the end of the period covered by the data.

Of the 948 measurements released, 238 of the results exceeded the 0.1 mg/m3 WES while workers were wearing protective equipment. In another 80 instances, workers had no protection.

Sydney Metro said it was incorrect to say one in three tests exceeded the WES as the limits had been changed.

One man now employed as a tunnel supervisor, speaking on the condition of anonymity due to “career-ending” implications of publicly discussing work site safety failures, said the prevalence of airborne hazards in tunnels was not matched by a commensurate protection for workers.

“All you see is clouds of dust. Anyone who works on these sites is at risk,” he said.

In a submission to the NSW parliamentary review of the Dust Diseases scheme, the AWU said the Transport for NSW data demonstrated exposure to silica on government projects was “grossly unacceptable”.

“RCS [respirable crystalline silica] exposure is irreversible: Once exposure occurs, workers have RCS in their lungs. Yet workers on many TfNSW tunnelling projects have been exposed to very high levels of RCS,” the submission, written by AWU assistant national secretary Chris Donovan, stated.

“Deeply troubling as it is, the TfNSW dataset is far from a complete record of dust disease exposure of our state’s tunnelling workforce.”

NSW government projects including NorthConnex, the M6 Stage 1, WestConnex and the Western Harbour Tunnel principally relied on mined tunnelling, the AWU said. Air-quality data was not provided for these sites.

Kate Cole, an expert on the workplace risks of silica dust, said the data demonstrated that tunnel workers were being exposed to “very high concentrations of the cancer-causing dust”, and the community should expect “waves of occupational disease to occur” as a result of building government-funded projects.

The AWU has previously warned that tunnel workers are being exposed to large amounts of silica dust.Credit: Kate Geraghty

Workers, families, the public health system and ultimately the taxpayer would suffer the cost, she said.

A spokesman for Work Health and Safety Minister Sophie Cotsis said SafeWork had agreed to meet the union regarding its concerns around air quality in tunnels.

Maurice Blackburn principal lawyer Jonathan Walsh, who represents 25 road tunnellers across NSW and interstate, said what was understood about the health hazards was “just the tip of the iceberg”.

“The data the AWU unveiled is shocking, but not surprising at all given the number of workers who we are seeing are unwell,” he said.

The number of workers who developed silicosis over the medium to long term was likely to be “in the thousands”, Walsh predicted, describing the situation as an “absolute disaster” already.

The union described SafeWork’s decision to withhold further data for tunnelling projects as “adversarial and obfuscatory”.

Greens spokeswoman for work health and safety Abigail Boyd said her office had been informed by workers that SafeWork was not inspecting tunnels properly, nor was protective equipment being used effectively.

“There is a conspiracy of silence between the workplace safety regulator and major construction companies to protect corporate profits at the expense of worker safety,” she said.

A SafeWork spokeswoman said the agency had a “sustained presence” on all major government projects to ensure best practice management of silica risks, saying inspectors conducted both “proactive and reactive” visits.

A Sydney Metro spokeswoman said workers were using respiratory protection in “almost all circumstances” where the Workplace Exposure Standard was breached, and that strict controls were in place to minimise exposure.

“While some of the air-quality tests do exceed the WES, numerous multi-level controls are implemented to prevent workers from being exposed,” she said.

A John Holland spokeswoman said health and safety was “our No.1 priority”. Air monitoring tests were provided to regulators as required, she said.

“We take all risks associated with tunnelling works seriously and comply with all relevant workplace health and safety regulations, including air monitoring of our sites.”

A spokeswoman for CPB Contractor said the company maintained “robust, non-negotiable” procedures and controls to manage safety risks.

Neither company explained why they argued against the disclosure of air-quality testing data.

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