Silica dust on residential construction sites in Australia

What it is

Respirable crystalline silica is the fine dust released when workers cut, grind, drill or polish materials that contain quartz. On a residential site that covers concrete, brick, masonry block, tile, pavers, fibre cement sheet and most natural stone. Workers who breathe it in over time develop silicosis, an irreversible lung disease, and have elevated risk of lung cancer, kidney disease and autoimmune conditions.

The Cancer Council estimates around 230 Australians develop lung cancer each year from past silica exposure at work. Construction is the dominant exposure pathway because the dust generation rate during dry cutting is extreme.

Engineered stone ban

From 1 July 2024 the manufacture, supply, processing and installation of engineered stone benchtops, panels and slabs is prohibited across all Australian jurisdictions. The ban was agreed by WHS ministers in December 2023 after Safe Work Australia found that workers in engineered stone fabrication had silicosis rates an order of magnitude higher than other silica-exposed trades. Transitional rules apply for installation of pre-fabricated stone where contracts were entered into before the cut-off, but those windows have now closed in every state.

A residential builder who arranges installation of engineered stone benchtops after the relevant transition date is exposed to direct prosecution. State regulators have already issued prohibition notices to fabricators operating outside the ban.

Workplace exposure standard

The workplace exposure standard for respirable crystalline silica is 0.05 milligrams per cubic metre averaged over an eight-hour shift. This was halved from 0.1 mg/m3 on 1 July 2020. The standard is enforceable under regulation 49 of the model WHS Regulations and the equivalent OHS Regulations in Victoria.

Air monitoring is required where exposure is reasonably likely to exceed half the standard. Health monitoring is required for any worker doing high-risk crystalline silica work without adequate controls. The 18 prescribed high-risk silica processes include cutting, grinding and polishing of concrete or masonry with power tools.

Where audits go wrong

SafeWork inspectors arriving on a residential site look at three things first. Are workers dry cutting bricks, blocks or pavers in open air with no water and no extraction. Is there an air monitoring report on file for any process that could push exposure above half the standard. Is health monitoring in place for workers exposed for more than a few hours per week.

The most common written direction issued on residential sites is for use of a hand-held angle grinder on masonry or concrete without water suppression or H-class vacuum extraction. WorkSafe Victoria and SafeWork NSW have both run targeted silica blitzes since the standard was halved and notice rates are high.

SWMS specifics

The SWMS for silica work has to name the actual control system on the actual tool. Generic entries like "use dust extraction" do not pass scrutiny. The inspector wants to see the make and model of the on-tool extraction unit, the filter class, the water flow rate for wet cutting, the respirator class and the cleanup method.

TradeLens audit triggers

A residential site flags as high risk on silica when any of the following appears. Dry cutting of brick or block visible on toolbox records. No air monitoring documentation despite power tool cutting of concrete or masonry. Engineered stone installation booked after the transition cut-off. No health monitoring records for workers who handle silica-bearing materials more than incidentally. Respirator selection that defaults to a P2 disposable for high-energy cutting where a powered air-purifying respirator is required.

What good looks like

Wet cutting as default for brick, block, paver, tile and concrete. On-tool H-class extraction for any indoor or enclosed cutting. P2 minimum respirators with face fit testing recorded by worker. Air monitoring run at least annually on representative tasks. Health monitoring through an occupational physician for any worker with regular silica exposure. SWMS that name the tool, the suppression method, the respirator and the cleanup protocol task by task.