The true toll of Sydney’s tunnel network: a system of silica dust

First came the grand opening that ended in traffic chaos. Then, a public outrage over pricey tolls gouging drivers. And now - a developing asbestos scandal has cemented WestConnex’s reputation: Australia’s most controversial road project.

WestConnex was promoted as a gateway connecting the centre of Sydney to the foot of the Blue Mountains. But the project has since drawn many criticisms, from cost overruns, compulsory acquisition and demolition of homes and businesses, inequitable tolls, and now worsening traffic congestion.

But these conversations have failed to highlight the most devastating human impact of Sydney’s growing tunnel network – the worsening epidemic of silica-related diseases among those workers who built them.

The sad reality of silica-related diseases

Over the last 30 years, New South Wales has completed several major tunnelling projects, including the Sydney Harbour Tunnel, WestConnex, and Snowy 2.0. More projects are on the horizon, including the Western Harbour Tunnel and Greater Western Highway.

These tunnels have largely been excavated by tunnellers, a highly technical group of workers specialising in the complex engineering and logistics associated with tunnel construction.

The process of tunnelling underground naturally puts tunnel workers at risk of significant dust exposure, including silica dust.

What is silica dust and where is it found?

Crystalline silica is a naturally occurring mineral present in varying quantities in most natural stone and soil. Tunnelling involves the mechanical excavating of rock and earth, a process that releases ultra-fine silica particles into the confined airspaces of a tunnel. The problem is compounded by the unique geology of the Sydney Basin, rich in so-called “Hawkesbury Sandstone”, which has an extremely high natural silica content, which is prone to become airborne when pulverised.

What are the risks associated with inhaling silica dust?

Those working in the confines of tunnels risk inhaling airborne silica particles. Prolonged exposure to silica dust has been linked to several conditions, including lung diseases, cancer, kidney disease, and multiple autoimmune disorders.

Of these diseases, silicosis is perhaps the most well-known. It is a lung disease which, in the worst cases, is terminal, but even in lesser cases, causes lifelong suffering and disability.

How many Australian tunnellers will suffer from silica-related diseases is still unknown

For many workers, their diseases will take years, even decades, to manifest. However, some workers may already be suffering from early-stage diseases but avoid reporting it or seeking treatment out of fear that a diagnosis could jeopardise their employment.

The threat posed to Australian tunnellers has always been entirely foreseeable. Silicosis is one of the first occupational diseases categorised in medical science, first documented in Italian marble workers in the 1700s.

How can we protect workers?

As tunnelling technology has improved, so have the methods available to protect tunnel workers from exposure to deadly dust. These include dust extraction and suppression systems, which reduce or remove airborne dust from tunnels, as well as advanced masks and respirators, which, if used properly, can shield individuals from dust exposure entirely.  However, implementing these measures inevitably requires more time, training, and money. This means workers need to rely on employers not to cut corners.

The tunnelling industry is not going away anytime soon. As Australian cities continue to sprawl and densify, new road projects will inevitably have to go underground. Transitioning to a low-carbon future will also necessitate new tunnelling projects, including public transport and hydroelectric schemes. This means that new generations of tunnel workers will continue to put their health and livelihoods at risk.

As a society that benefits from these infrastructure projects, we owe it to the workers building the tunnels to make sure every possible measure is taken to protect their health and wellbeing and that any employers found to be skirting the rules are held to account.

And for those workers already suffering from silica-related diseases, we must ensure that they and their families get all the support and compensation they are entitled to.