Construction: Preventing exposure to crystalline silica dust

What is crystalline silica?

Crystalline silica is a natural mineral found in construction materials such as concrete, bricks, tiles, mortar and engineered stone. It includes substances such as quartz, cristobalite, tridymite or tripoli.

Common materials and their typical crystalline silica content include:

• sandstone, 70% to 90%
• granite, 25% to 60%
• ceramic tiles, 5% to 45%
• autoclaved aerated concrete, 20% to 40%
• slate, 20% to 40%
• concrete, less than 30%
• porcelain, 14% to 18%
• brick, 5% to 15%
• marble, less than 5%
• engineered stone, 1% or more crystalline silica, determined as a weight/weight concentration

Crystalline silica dust

Crystalline silica dust is generated when these substances are mechanically processed, for example, through construction activities such as cutting or grinding. These dust particles are small enough to be breathed deep into the lungs

Exposure to crystalline silica dust over a long period at low to moderate levels, or short periods at high levels, can lead to serious health conditions such as silicosis. Silicosis is an irreversible, incurable and progressive lung disease that can lead to disability and death.

Construction and demolition employees can be at risk of developing these diseases. Employers have duties to manage risks from crystalline silica dust under Part 4.1 (Hazardous substances) and Part 4.5 (Crystalline silica) of the Occupational Health and Safety Regulations 2017 (OHS Regulations).

If you are unsure whether a product contains crystalline silica, check the safety data sheet (SDS) or other information from the manufacturer or supplier.

For more information, see the guidance, Duties of manufacturers and suppliers of crystalline silica substances.

For more information about SDSs, see the Hazardous substances compliance code.

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Engineered stone ban

From 1 July 2024, the manufacture, supply, processing or installation of engineered stone benchtops, panels or slabs is banned in Victoria. The engineered stone ban applies to engineered stone benchtops, panels and slabs. Engineered stone products not in these forms are not banned. There are limited exceptions to the ban where work can be performed on engineered stone benchtops, panels and slabs. This includes:

• removal, repair or modification of installed engineered stone benchtop and panels
• disposal of installed or uninstalled engineered stone benchtops, panels and slabs
• research and analysis and; to sample and identify engineered stone

Specific controls are required when permitted engineered stone work involves an engineered stone process. An engineered stone process is also considered high risk crystalline silica work and you must comply with the high risk crystalline silica work obligations.

For more information, see Working with engineered stone and Frequently asked questions - Engineered stone ban.

Workplace exposure standard

Safe Work Australia publishes exposure standards for airborne contaminants in the workplace.

Under the OHS Regulations, employers must ensure employees are not exposed to respirable crystalline silica dust at the workplace at a level above the exposure standard. 

The exposure standard for crystalline silica dust, listed under Quartz, Cristobalite, Tridymite, Tripoli (respirable dust), is 0.05mg/m3 as a time-weighted average (TWA) airborne concentration over 8 hours.

An 8-hour TWA exposure standard is the maximum average airborne concentration of a particular substance permitted over an 8-hour working day, for a 5-day working week.  Where a workplace has working hours that exceed an 8-hour day or a 40-hour week, the TWA needs to be adjusted to compensate for the greater exposure. The adjusted exposure standard for crystalline silica dust over a 10-hour day would be 0.035mg/m3.

The workplace exposure standard for respirable crystalline silica is based on the airborne concentration within a person's breathing zone, outside of any respiratory protective equipment that may be in use.

Employers are required to ensure employee exposure does not exceed this standard.

WorkSafe Victoria recommends that employees are not exposed to levels above 0.02mg/m3 as an 8-hour TWA. This is a precautionary measure to prevent silicosis and to minimise the risk of lung cancer.

What is a crystalline silica process

A crystalline silica process means one or more of the following processes carried out at a workplace:

• The use of a power tool or other form of mechanical plant to cut, grind, polish, or crush material containing crystalline silica or to carry out any other activity involving material containing crystalline silica that generates crystalline silica dust.
• The use of a roadheader on an excavated face if the material in the face contains crystalline silica.
• A process that exposes a person to crystalline silica dust arising from the manufacture or handling of material that contains crystalline silica.
• The mechanical screening of crushed material containing crystalline silica.
• A quarrying process involving material containing crystalline silica.
• A tunnelling process involving material containing crystalline silica.
• A process determined by WorkSafe to be a crystalline silica process.

What is high risk crystalline silica work

High risk crystalline silica work (HRCSW) is:

• an engineered stone process, or
• work performed in connection with a crystalline silica process that is reasonably 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

For more information about permitted work with engineered stone, see Working with engineered stone.

Identifying high risk crystalline silica work

Before starting a crystalline silica process, an employer or self-employed person must identify whether the crystalline silica processes are HRCSW. This must be done by conducting a risk assessment or by choosing to treat that work as HRCSW without doing a risk assessment.

If doing a risk assessment, the employer or self-employed person must consider the following factors:

• The specific tasks or processes required to be undertaken with material that contains crystalline silica.
• The form of crystalline silica to be used, for example, brick, concrete, crushed rock.
• The proportion of crystalline silica contained in the material.
• The previous atmospheric monitoring results.
• The likely frequency and duration of exposure to crystalline silica dust.
• Any information about incidents, illnesses or diseases associated with exposure to crystalline silica dust at the workplace.

For more information about risk assessments, see the guidance, Preparing a crystalline silica hazard control statement for high-risk crystalline silica work.

A flow chart to step you through this process is available on the WorkSafe website.

Crystalline silica hazard control statement

A crystalline silica hazard control statement (hazard control statement) is a document prepared for HRCSW carried out at a workplace. Similar to a safe work method statement (SWMS) for high risk construction work, it sets outs the hazards and risks arising from the work and details the measures to control those risks and how they will be implemented. If the HRCSW is being undertaken as part of high risk construction work, the hazard control statement can be incorporated into a SWMS.

An employer or a self-employed person must not perform HRCSW unless:

• a crystalline silica hazard control statement is prepared for the work before the work begins, and
• the work is performed in line with that hazard control statement

If the work is not performed in line with the hazard control statement, the employer or self-employed person must stop that work immediately or as soon as it is safe to do so. Work must not resume until the hazard control statement is complied with or reviewed and, if necessary, revised in line with the OHS Regulations.

An employer must review and revise the hazard control statement:

• whenever the HRCSW changes
• whenever there is an indication that risk control measures are not adequately controlling the risk
• after any incident that occurs during the HRCSW

The hazard control statement must do the following:

• State the hazards and risks to health associated with the HRCSW.
• Clearly detail the measures selected to control those risks. Risks must be controlled in line with the hierarchy of controls in this guidance.
• Describe how the risk control measures will be put into effect.
• If an analysis is required of samples, contain the results of that analysis. See information under the heading, Quarrying and tunnelling processes.
• Be set out and expressed in a way that is readily accessible and clear to the people who use it.

For more information on the duties related to developing a hazard control statement and putting it into effect, see the guidance, Preparing a crystalline silica hazard control statement for high risk crystalline silica work.

A hazard control statement is not required for HRCSW where:

• a SWMS has been prepared, and
• the SWMS addresses the matters required for a hazard control statement
   

Quarrying or tunnelling processes

If the HRCSW involves a quarrying or tunnelling process, the employer or self-employed person must, before the work begins:

• collect samples of materials to be used in the quarrying or tunnelling process, and
• arrange for analysis of those samples by a suitably competent person to identify the proportion of crystalline silica in each sample

The hazard control statement must contain the results of that analysis.

For further information on the duties related to quarrying processes, see the guidance, Dust containing crystalline silica in the extractive industry.

Controlling the risk of exposure

Employers must control the risks associated with exposure to crystalline silica by applying the hierarchy of control in Part 4.1 (Hazardous substances) of the OHS Regulations.

An employer must, so far as is reasonably practicable, eliminate the risks associated with exposure to crystalline silica dust in their workplace, for example, by using non-silica-containing products.

If it is not reasonably practicable to eliminate a risk associated with crystalline silica, the employer must reduce the risk so far as is reasonably practicable by:

• substitution, for example, instead of using engineered stone which can be up to 95% silica, use natural stone, which can have a much lower silica content
• isolation, for example using automated wet machines
• engineering controls, for example using on-tool water suppression, or
• a combination of any of these risk control measures

If the risks from exposure still remain after the listed risk control measures have been implemented, administrative controls must be used to reduce the risk so far as is reasonably practicable. Administrative controls include, for example, rotation during shifts between high and low-exposure tasks.

If, after implementation of administrative controls, a risk to health from exposure to crystalline silica dust remains, reduce that risk, so far as is reasonably practicable, by providing appropriate personal protective equipment (PPE) to employees at risk (for example respiratory protective equipment such as a half face negative respirator or powered air purifying respirator (PAPR)).

If a risk remains, an employer must provide appropriate personal protective equipment, such as respiratory protective equipment (RPE).

It is most likely that more than one control will be needed to control the risk adequately.

Employers must consult with their employees, including independent contractors, and any health and safety representatives (HSRs), so far as is reasonably practicable, when identifying hazards and risks associated with crystalline silica exposure. Employers must also consult when deciding on how to control risks.

When engineered stone processes are undertaken, specific risk controls must be used in addition to the requirement to apply the hierarchy of control in Part 4.1 of the OHS Regulations.

For information on permitted work with engineered stone, see Working with engineered stone.

High risk crystalline silica work hiring requirements

Employers must ensure that applicants for jobs involving high risk crystalline silica work are given information about:

• the health risks associated with exposure to respirable crystalline silica
• the need for measures to control those risks
• details about the control measures

Information, instruction and training

Information, instruction and training needs to be provided to employees who are likely to be exposed to risks associated with undertaking high risk crystalline silica work, including on:

• the health risks associated with exposure to crystalline silica dust
• the need for any risk control measures required by the OHS Regulations
• the proper use of any risk control measures required by the OHS Regulations
• how the risk control measures are to be implemented

The structure, content and delivery of the training needs to consider any specific requirements of the employees being trained. For example, information, instruction and training may need to be provided in a language other than English. Refresher training should be provided regularly.

Atmospheric monitoring

Atmospheric monitoring, also known as air monitoring, for crystalline silica involves sampling the air for respirable crystalline silica within the employees’ breathing zone.

By law, employers must carry out atmospheric monitoring, also known as air monitoring if:

• they are not sure if their employees are exposed to levels of silica dust that are above the exposure standard
• they can't work out if there's a risk to employee health without air monitoring

Employers should carry out atmospheric monitoring:

• when there are changes to work practices, the materials being used or the work environment
• if a health monitoring report for an employee indicates a negative change in health status which may be related to silica exposure
• if an HSR requests a review of control measures because there is uncertainty based on reasonable grounds as to whether the exposure standard is or may be exceeded
• if there are changes to the workplace exposure standard, and previous atmospheric monitoring results have indicated levels above the new standard.

The interpretation of these results, including comparison with the exposure standard, should be carried out by a competent person, to determine employee exposure to crystalline silica dust. An occupational hygienist is an example of a competent person.

Results of air monitoring must be shared as soon as reasonably possible with employees who have been or may have been exposed.

For more information, see the Exposure standards and atmospheric monitoring guidance.

Health monitoring

Employers must ensure health monitoring is carried out for an employee if exposure to crystalline silica is reasonably likely to have an adverse effect on the employee’s health.

Health monitoring must be done under the supervision of a registered medical practitioner.

Health monitoring should be carried out by a specialist occupational and environmental physician or respiratory physician with expertise in respiratory and silica exposure health monitoring. A list of practitioners is available on the Royal Australasian College of Physicians website.

Where health monitoring is required, it must be completed in line with the recommendations of the registered medical practitioner. This may include:

• regular testing periods while employees are in the job
• before newly hired employees start work with a new employer
• when employees finish working for that employer

Employers who were previously engineered stone licence holders have specific health monitoring requirements for employees. For this information, see Working with engineered stone.