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.

Common stone products and their typical crystalline silica content include:

• engineered stone: 40% to 95%
• ceramic tiles: 5% to 45%
• autoclaved aerated concrete: 20% to 40%
• concrete: less than 30%
• brick: 5% to 15%
• marble: less than 5%

These substances are not defined as hazardous substances in their solid form.

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

Exposure to crystalline silica dust over a long period of time at low to moderate levels, or short periods at high levels can lead to serious health conditions such as silicosis, which 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.

If you are unsure if a product contains crystalline silica, check the safety data sheet (SDS) or other information from the manufacturer or supplier. For more information, see guidance on Duties of manufacturers and suppliers of crystalline silica substances. For more information about SDSs, see the Hazardous substances compliance code.

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Working with engineered stone

Engineered stone is also known as reconstituted, artificial or manufactured stone. The uncontrolled dry cutting of engineered stone is prohibited in Victoria.

Specific duties and risk control measures must be complied with when working with engineered stone.

This guidance does not include information about the specific duties and risk controls required when working with engineered stone.

Workplace exposure standard

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

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

An 8-hour time-weighted average 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 longer 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 eight 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 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

Identifying high risk crystalline silica work

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

If conducting a risk assessment, the employer or self-employed person must take into account the following factors:

• the specific tasks or processes required to be undertaken with material containing 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
• previous atmospheric monitoring results
• the likely frequency and duration of exposure to crystalline silica dust, and
• any information about incidents, illnesses or diseases associated with exposure to crystalline silica dust at the workplace

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

Crystalline silica hazard control statement

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

• a crystalline silica hazard control statement (hazard control statement) is prepared for the work before the work commences, and
• the work is performed in accordance with that hazard control statement.

If the work is not performed in accordance 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 accordance with the Occupational Health and Safety Regulations 2017 (OHS Regulations).

The hazard control statement must:

• state the hazards and risks to health associated with the HRCSW
• clearly detail the measures selected to control those risks in accordance with the hierarchy of controls (outlined below)
• describe how the risk control measures will be implemented,
• if an analysis is required of samples, contain the results of that analysis (see quarrying and tunnelling processes below)
• be set out and expressed in a way that is readily accessible and comprehensible to the persons who use it.

Note: Depending on the activity being undertaken, the risk control measures may be more extensive than what is otherwise required by the OHS Regulations, Part 4.1 Hazardous Substances, regulation 163. A hazard control statement must also include any specific risk controls required by Part 4.5 Crystalline Silica of the OHS Regulations.

A hazard control statement is not required for HRCSW where a safe work method statement (SWMS) has been prepared which addresses the matters required for a hazard control statement.

However, a SWMS cannot be substituted where a hazard control statement is required for an engineered stone process.

Quarrying or tunnelling processes

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

• 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 contained in each sample.

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

For more information on the duties related to the development and implementation of a hazard control statement please see Preparing a crystalline silica hazard control statement for high risk crystalline silica work guidance.

Further information on the duties related to quarrying processes; please see Dust containing crystalline silica in the extractive industry.

Controlling the risk

The risk control measures required by the OHS Regulations are different for different types of work. To determine what risk controls you are required to use, you will first need to determine whether the work you are doing is a crystalline silica process, a high risk crystalline silica process (defined above) or an engineered stone process. Note this guidance does not provide information on engineered stone processes.

When selecting measures to control the risk to health from exposure to crystalline silica dust, the employer must apply the following hierarchy of controls.

Where there is any risk to health from exposure to crystalline silica dust, employers must first seek to eliminate that risk so far as is reasonably practicable, for example by using materials that do not contain crystalline silica.

If a risk cannot be eliminated, it must be reduced so far as is reasonably practicable, by implementing one (or a combination) of the following:

• substituting crystalline silica with a substance that is less hazardous, or a less hazardous form of crystalline silica, for example materials with a lower crystalline silica content
• isolating persons from exposure to crystalline silica, for example excavator operators working in a pressurised cabin with a HEPA filtration system
• using engineering controls, for example using handheld tools with on-tool water suppression or on tool dust extraction

If, after implementation of the above controls, a risk to health from exposure to crystalline silica dust remains, reduce the risk, so far as is reasonably practicable, by using administrative controls (for example, reducing the duration and/or frequency of exposure through job rotation, implementing and maintaining good housekeeping practices including regular cleaning of work areas with H or M class vacuums or water).

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)).

Employers and self-employed persons will likely need to use a combination of control measures to reduce the risk to health.

Consultation

Employers must consult with their employees (including independent contractors), and any health and safety representatives, when identifying hazards and risks associated with crystalline silica exposure, and when deciding on how to control risks.

Please see Preparing a crystalline silica hazard control statement for high risk crystalline silica work guidance.

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

Employers must provide information, instruction and training to employees on:

• the fit, use, maintenance and storage of RPE if it is used as a risk control measure
• how to dispose of waste
• methods for personal decontamination

The structure, content and delivery of the training needs to take into account any special 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

Employers must carry out atmospheric monitoring for crystalline silica dust generated at their workplace where:

• there is uncertainty about whether the exposure standard is or may be exceeded, or
• air monitoring is necessary to determine whether there is a risk to employee health

Employers should conduct air 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 a health and safety representative 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

Atmospheric monitoring and the interpretation of results (including comparison with the exposure standard) should be conducted by a competent person (such as an occupational hygienist) to determine employee exposure to crystalline silica dust.

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

Where possible, air monitoring results should be shared with medical practitioners who are conducting health monitoring for employees.

Health monitoring

Employers must ensure that 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 carried out 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 can be found on the Royal Australasian College of Physicians website at (link below). Employers should speak to the occupational physician to ensure they have experience with silicosis and other silica dust diseases.

Where health monitoring is required, it must be completed in line with the recommendations of the supervising medical practitioner. This may include regularly while they are in the job, when an employee is hired with a new employer (before they start work), and when they finish working for that employer.