Do You Need Crystalline Silica Air Monitoring at Your Workplace?
The question
If your workers cut, grind, drill, polish, crush, or disturb materials containing crystalline silica, you are required to assess whether air monitoring is necessary. Crystalline silica is present in concrete, brick, stone, masonry, mortar, tiles, sand, and engineered stone. The question is not whether silica is present. It is whether your workers are exposed to respirable crystalline silica above safe levels, and whether your current controls are adequate.
The regulatory requirement
Victorian OHS Regulations Part 4.3 requires you to identify hazardous substances at the workplace, assess the risk of exposure, and implement controls. Where elimination and substitution are not reasonably practicable, you must ensure exposure is kept below the workplace exposure standard.
The national workplace exposure standard for respirable crystalline silica is 0.05 mg/m3 averaged over an eight-hour shift. This is the legal limit you must not exceed. However, WorkSafe Victoria recommends that exposure be reduced below 0.02 mg/m3 as a precautionary measure to prevent silicosis and minimise the risk of lung cancer.
You cannot confirm compliance with either standard without air monitoring. Visual inspection, dust suppression systems, and respiratory protection do not provide measured evidence that exposure is below the legal limit or the Victorian target. Air monitoring does.
When monitoring is required
Air monitoring is required when there is uncertainty about whether exposure exceeds the standard, when new work processes are introduced, when control measures are modified, or when you need to verify that existing controls remain effective. If workers are performing tasks known to generate high levels of silica dust and you have not conducted air monitoring to confirm exposure levels, you have not met your obligation to assess the risk.
What air monitoring involves
Personal breathing zone monitoring measures the concentration of respirable crystalline silica in the air a worker breathes during their shift. A sampling pump is fitted to the worker at the start of the shift and draws air through a filter positioned in the worker's breathing zone. At the end of the shift, the filter is sent to a NATA accredited laboratory for analysis using X-ray diffraction methods.
Static area sampling can be used to map dust levels across different zones of the workplace, but it does not replace personal monitoring. Personal monitoring measures what the worker breathes. Static monitoring measures what is in the air nearby.
Common failures
- Assuming water suppression eliminates the need for monitoring.
- Relying on respiratory protective equipment without monitoring.
- Using one-off monitoring from years ago to justify current work practices.
- Assuming compliance because results were below 0.05 mg/m3.
Your obligations
Conduct air monitoring where there is uncertainty about exposure levels, where high-risk tasks are performed, or where you need to verify control effectiveness. Engage a competent occupational hygienist to design the monitoring program, select appropriate workers and tasks for sampling, and interpret results against both the national standard and the Victorian target.
Provide workers with monitoring results and keep records of monitoring results, including the date, location, task monitored, worker details, sampling duration, laboratory analysis method, and measured concentration.
Consequences of non-compliance
Silicosis is now diagnosed in workers across construction, manufacturing, and stone fabrication industries. WorkSafe Victoria has issued prohibition notices, improvement notices, and prosecuted employers who failed to monitor silica exposure or implement adequate controls.
If you are uncertain whether monitoring is required at your workplace, contact an occupational hygienist to conduct a preliminary assessment of silica-generating tasks, materials in use, and current control measures.