Engineered stone is a man-made product made by mixing natural stone materials with other chemicals like water, resins, and pigments. It is commonly used for bathroom and kitchen surfaces and is marketed as a durable and easy-to-maintain option. However, the dust generated from cutting or polishing the product is toxic and can be harmful when inhaled.
The consultation paper from Safe Work Australia presents three policy options for a prohibition on the use of engineered stone, and the AIOH has submitted feedback on these options based on an evidence-based approach. Factors considered include the nature of the hazard, relevant exposure science, at-risk occupations and exposure scenarios, and compliance practices, among others.
There are four ways workers can be exposed to harmful emissions: primary exposure (being close to the source), bystander exposure (being far from the source but still inhaling particles), secondary exposure (dust that settles or is re-suspended), and inhalation of dust-containing mist particles in recycled water.
Our review concluded that the argument for a 40% cut-off for crystalline silica content in products is flawed. This is because the dust from engineered stone, which often contains a high percentage of crystalline silica, has different properties than dust from natural stone. Natural stone also varies in its silica content and cases of silicosis occur in workers who process natural stone and minerals with silica content well below 40%. The risk of silicosis is not acceptable for workers in either natural stone or engineered stone. The aim of the National Dust Disease Taskforce and the government is to eliminate silicosis, so selecting an “acceptable” percentage of crystalline silica would be inconsistent with this goal.
Emissions released from processing engineered stone are different from those released from processing natural stone. Even when using methods like wet-cutting and ventilation, it’s hard to control the amount of silica dust in the air to below regulatory limits. Recent studies have shown that even with these methods, workers are still exposed to too much silica dust. This means that workers need to routinely wear respiratory protection to protect themselves. There are compliance issues with safety practices in the stone industry, and therefore a cautious approach is needed.
Based on the available literature and information, a percentage that is protective of worker health, or “safe” cannot be determined. While a cut-off of 10% crystalline silica (by weight) can be expected to keep average exposures to RCS below the Workplace Exposure Standard (WES) based on the weight of evidence from real world and academic studies, our review found that there are also other products in engineered stone that can cause health issues. Amorphous silica from recycled glass can also be present which is also harmful when inhaled. Therefore a precautionary approach is warranted.
The precautionary principle is a way of making decisions that says if there is a chance that something could harm people’s health, we should take steps to protect them, even if we’re not completely sure how much harm it could cause. This principle is used in laws and policies across Australia to protect public health. We are of the opinion that Safe Work Australia should follow this principle when making a final decision on engineered stone, instead of using a limit that may not fully protect workers from permanent health effects.
Therefore, the AIOH is supportive of a prohibition on the use of engineered stone, including a prohibition on the use of all engineered stone irrespective of its crystalline silica content.
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