Silicosis

Silicosis is a chronic, incurable lung disease caused by inhaling unsafe levels of respirable crystalline silica dust. Silica dust is created when materials such as stone, rock, sand, concrete or clay are cut, crushed, ground, polished or drilled. The risk is greatest when these tasks are performed without effective dust control measures or appropriate respiratory protection. When inhaled, these fine particles can become trapped in the lungs, causing chronic inflammation and permanent scarring (fibrosis) that makes it increasingly difficult to breathe. How much silica dust a person breathes in, and for how long, affects the type of silicosis they may develop. It can result from high levels of exposure over weeks or months, or smaller amounts over many years.

Silicosis caused by engineered stone is particularly aggressive. Unlike traditional silicosis, which typically develops after decades of exposure, this ‘accelerated silicosis’ can develop after just a few years of exposure and progresses more rapidly. Many of those diagnosed are only in their 20s and 30s. Screening programs in Queensland and Victoria have found that around one in four workers exposed to silica dust from engineered stone has been diagnosed with silicosis. The disease can be terminal, although life can be prolonged with a lung transplant.

Silicosis is a serious occupational lung disease that has re-emerged in Australia at alarming rates, driven by tradespeople cutting, grinding and polishing engineered (artificial) stone benchtops. Engineered stone became ubiquitous in Australian kitchens and bathrooms from the early 2000s as an affordable alternative to marble or granite, but it often contained up to 95 per cent crystalline silica, far more than the natural stones it replaced, such as granite (25–60 per cent) and marble (less than 5 per cent).

Anyone who works with materials that contain silica and generates dust can be at risk of silicosis. The risk is highest for workers who cut, drill, grind, crush or polish materials such as engineered stone, concrete, brick, rock and natural stone, particularly if dust controls and respiratory protection are inadequate.

High-risk occupations include:

• Stone benchtop fabrication and installation, especially work involving engineered stone
• Construction work, including jackhammering, rock drilling and chipping, tunnelling, sandblasting, asphalt milling, and cutting concrete, brick and tiles
• Ceramics and glass manufacturing
• Mining, quarrying and hydraulic fracturing (fracking).

People with silicosis usually have no symptoms in the early stages of the disease; many workers are diagnosed through health screening before they feel unwell. If the disease progresses, symptoms may develop slowly, even after exposure to silica dust has stopped.

Common symptoms of silicosis include:

• Shortness of breath
• Cough
• Tiredness and fatigue
• Chest pain
• Weight loss.

Breathing in silica dust can also cause other serious conditions, including lung cancer, chronic obstructive pulmonary disease (COPD), kidney disease, autoimmune diseases such as scleroderma, and an increased risk of infections such as tuberculosis.

Employers are legally required to provide regular health monitoring, at their own expense, for workers whose exposure to crystalline silica is reasonably likely to affect their health, including a baseline assessment before work begins, so that any changes can be detected early. Early and accurate identification of silicosis allows for earlier intervention, which can improve health outcomes.

A health assessment may involve a review of work and medical history, a physical examination focused on the respiratory system, blood tests, lung function tests, and chest imaging (X-ray and/or CT scan).

Importantly, chest X-rays and standard lung function tests have proven unreliable for detecting early silicosis in stone benchtop workers, and more sensitive tools are needed. This diagnostic gap is one that Hudson Institute’s biomarker research aims to address.

There is currently no cure for silicosis, and no treatment that can reverse the lung scarring once it has occurred. The best protection is prevention: eliminating or strictly controlling exposure to silica dust.

For people who have been diagnosed, management focuses on slowing the progression of the disease, relieving symptoms and avoiding any further exposure. Options may include anti-fibrotic medications and inhaled medications used for people who also have asthma, COPD or another lung disease. None of these options can remove the underlying cause or halt the disease for everyone, which is why research into new treatments that target the inflammation driving silicosis is so urgently needed.