Crystalline silica (respirable dust) is a natural mineral found in many construction materials, such as stone, soil, sand and engineered stone. The amount of crystalline silica in products can vary, for example:
- Engineered stone: 80 - 95%
- Ceramic tiles: 5 - 45%
- Concrete: less than 30%
- Brick: 5 – 15%
- Marble: less than 5%
There is some respirable dust that is included as crystalline silica in accordance with the Safe Work Australia:
- Quartz (SiO2) (respirable fraction) – CAS: 14808-60-7
- Cristobalite – CAS: 14464-46-1
- Microcrystalline silica (Tripoli) – CAS: 1317-95-9
- And possibly Tridymite – CAS: 15468-32-3
When unsure if a product contains crystalline silica, check the safety data sheet (SDS) or other information from the supplier.
When a process of cutting, grinding, polishing or crushing material containing crystalline silica (crystalline silica work) is carried out, fine dust containing respirable crystalline silica will be released into the air. If not controlled appropriately, this respirable crystalline silica is hazardous to health that can lead to serious diseases like:
- Lung cancer
- Kidney disease
- Autoimmune diseases, such as scleroderma
While Safe Work Australia publishes the exposure standard for respirable crystalline silica dust as 0.05 mg/m3 as a time-weighted average (TWA), WorkSafe Victoria recommends exposure to below 0.02 mg/m3 as an 8-hour TWA, which is followed by the University.
The Occupational Health and Safety Regulations 2017 (Vic) have been amended to cover the safety requirements when working with respirable crystalline silica. The Regulations cover specific control measures to be used when working with engineered stone (Part 4.5, Division 3, subdivision 3).
Controlling exposure risk
When practicable, eliminate the risk associated with exposure to crystalline silica. If it is not reasonably practicable to eliminate the risk, then the risk must be reduced as far as is reasonably practicable by substitution, isolation, engineering control or a combination of those control measures. Risk control measures should include, as a minimum, the following considerations:
- Elimination – use materials that do not contain crystalline silica.
- Substitution – use materials with lower amounts of crystalline silica such as natural stone.
- Isolation – use automated fully enclosed and contained machines to cut, grind, or polish stone slabs.
- Engineering Controls - On-tool water suppression or on-tool dust extraction is an effective engineering control that should be used when there is potential exposure to crystalline silica. Dust Class M or H vacuum cleaner or wet methods to clean dusty floors are used during clean up.
- PPE - When engineering controls can’t adequately control the dust, then respiratory protective equipment (RPE) must be provided. The RPE must comply with AS/NZS 1716 – Respiratory protective devices. It should be at minimum a P2 filter. Consideration should also be given to respiratory protective equipment (PPE) such as a half-face negative respirator or powered air-purifying respirator (PAPR) in higher-risk environments.
NOTE – Risks must be considered during storage, transport, handling, cleaning and use of materials containing crystalline silica.
Information, instruction, training and supervision must also be provided, for example:
- The hazard and risks of working with crystalline silica
- How to effectively use the control measures, wear the RPE properly and clean up
- How to dispose of the waste, and
- Personal decontamination
Working with high-risk crystalline silica dust
“High-risk crystalline silica work” is work performed in connection with a crystalline silica process that is likely to result in an airborne concentration of respirable crystalline silica that exceeds half the exposure standard for respirable crystalline silica, or a risk to the health of a person at the workplace.
All crystalline silica work must be treated as high-risk crystalline silica work until it can be confirmed that the process or combination of processes is not high-risk crystalline silica work. When there is uncertainty if the exposure standard is or may be exceeded, air monitoring must be carried out.
- An employer must ensure that their employee or their direct contractor involved in high-risk crystalline silica work is given training and information about crystalline silica hazards and controls;
- A crystalline silica hazard control statement (or SOP) must be developed that:
- States the hazards and risks associated with that work;
- Sufficiently describes measures to control those risks;
- Describes how the risk control measures are to be implemented;
- Is readily accessible and comprehensible to the person who uses it, and
- If analysis of air monitoring is required, it contains the results of that analysis
Working with engineered stone
Engineered stone licences should be verified prior to UoM engineered stone subcontractor engagement
Engineered stone is a manufactured composite stone material that contains more than 80% crystalline silica. These products are commonly used as benchtops in bathrooms and kitchens.
An “Engineered stone process” is a process involving engineered stone at a workplace that generates crystalline silica dust, including cutting, grinding or abrasive polishing of engineered stone.
A supplier including importers of engineered stone must provide adequate safety information of their product. This can be in a form of a safety data sheet (SDS).
The engineered stone process at a workplace must be managed under an Engineered Stone Licence after 15 November 2022, in accordance with the Occupational Health and Safety Amendment (Crystalline Silica) Regulations 2021 S.R. No. 137/2021. The duties of the licence holder (employer):
- Prepare an engineered stone control plan identifying hazards and controls to be implemented for all engineered stone processes;
- Ensure that an applicant who applies for employment with the employer at a workplace where an engineered stone process is undertaken is given information about crystalline silica hazards and controls;
- Provide power tools or other forms of mechanical plant to undertake an engineered stone process that has an integrated water delivery system or an on-tool dust extraction system;
- Provide respiratory protective equipment;
- Provide employees who are likely to be exposed to risks associated with an engineered stone process - with information, instruction and training about crystalline silica hazards and controls, and,
- Ensure monitoring is carried out for employees likely to be exposed to risks associated with an engineered stone process under the supervision of:
- a specialist occupational and environmental physician; or
- a specialist respiratory and sleep medicine physician.
- Further information