Focus on Crystalline Silica Substances: Air monitoring

Persons Conducting a Business or Undertaking (PCBUs) have a legal duty to ensure, so far as is reasonably practicable, the health and safety of workers and identifying risks associated with hazardous substances in the workplace.

One such hazardous substance is respirable crystalline silica (RCS)—a fine dust generated during tasks such as cutting, grinding, or drilling materials like concrete, bricks, tiles, or stone.

PCBUs must take proactive steps to eliminate or minimise exposure to RCS, which can cause serious health conditions such as silicosis, lung cancer, and other respiratory diseases.

Ensuring proper control measures, safe work practices, and worker training are in place is essential.

A crystalline silica substance (CSS) is defined as any material containing at least one per cent crystalline silica by weight and stipulates that all processing be controlled.

In accordance with section 529B of the Work Health and Safety Regulation 2011 (WHS Regulation), processing is ‘controlled’ if control measures are implemented, so far as is reasonably practicable, to eliminate or minimise risks arising from the processing and at least one of the following control measures is used during the processing:

• the isolation of a person from dust exposure;
• a fully enclosed operator cabin, fitted with a high efficiency air filtration system;
• an effective wet dust suppression method;
• an effective on-tool extraction system;
• an effective local exhaust ventilation system.

Should a person still be at risk of exposure to respirable crystalline silica (RCS) despite these control measures, suitable Respiratory Protective Equipment (RPE) must be provided and worn.

When should I conduct air monitoring?

Under Queensland’s work health and safety legislation, a person conducting a business or undertaking (PCBU) must conduct air monitoring for RCS if they are not certain whether or not the Workplace Exposure Statement (WES) has been exceeded.

There are several ways a PCBU can be certain on reasonable grounds:

• By using all the recommended controls for the task as specified in Appendix 4 (Managing respirable crystalline silica dust exposure in construction and the manufacturing of construction elements code of practice 2022), including RPE if required by the table.
• By using statistically valid exposure data for the task to demonstrate the higher order controls you are using minimise workers’ exposure to RCS below the WES, without the need for RPE.
• By using statistically valid exposure data for the task to demonstrate the combination of higher order controls and suitably rated RPE you are using minimise workers’ exposure to RCS below the WES.

If the PCBU is certain on reasonable grounds that the WES has not been exceeded, using Appendix 4 or statistically valid exposure data, they are not required to conduct air monitoring.

If the PCBU is not using Appendix 4 and does not have statistically valid exposure data to demonstrate the controls they are using protect workers from exposure to RCS at levels that exceed the WES, they can’t be reasonably certain and must conduct air monitoring.

More information

For more information about how to manage crystalline silica substances, go to:

• Regulation on processing crystalline silica substances
• Managing respirable crystalline silica dust exposure in construction and the manufacturing of construction elements code of practice 2022
• Model Code of Practice: Managing risks of respirable crystalline silica in the workplace | Safe Work Australia