Stonemasons: Preventing crystalline silica exposure

What is crystalline silica?

Crystalline silica is a natural mineral. It's found in natural and man-made materials such as engineered stone, granite and sandstone. It includes substances such as quartz, cristobalite, tridymite and 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

From 1 July 2024, engineered stone is defined as an artificial product that:

• contains 1% or more crystalline silica, determined as a weight/weight concentration, and
• is created by combining natural stone materials with other chemical constituents such as water, resins or pigments, and
• becomes hardened

Engineered stone does not include the following:

• concrete and cement products
• bricks, pavers and other similar blocks
• ceramic wall and floor tiles
• sintered stone and porcelain products that do not contain resin
• roof tiles
• grout, mortar and render
• plasterboard

High levels of crystalline silica may also be found in some natural stone products. To find out how much crystalline silica is in a product, check the safety data sheet (SDS) or other information from the supplier.

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 (HRCSW) and you must comply with the HRCSW obligations.

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

Stonemasons and exposure to crystalline silica dust

Tasks such as cutting, grinding or abrasively polishing stone products release respirable crystalline silica dust – dust particles small enough to breathe into your lungs. This dust may not be visible.

Stonemasons are exposed to crystalline silica dust, especially when using power tools to cut, grind or polish stone products. People working in benchtop fabrication are at a higher risk because they regularly work with engineered stone, which can have a very high crystalline silica content.  Stonemasons working with natural stone and other crystalline silica-containing materials must control the risk of exposure to crystalline silica dust.

Health risks

Silica dust can be harmful when inhaled into the lungs over a long period of time at low to moderate levels, or short periods at high levels.

When respirable crystalline silica dust is inhaled it can cause silicosis, which is a scarring of the lungs. Silicosis is a serious and incurable disease, with symptoms including shortness of breath, coughing, fatigue and weight loss. In severe cases, the damage caused to the lungs by silicosis can require a lung transplant or may even lead to death.

In recent years, identified cases of silicosis have been increasing, in particular 'accelerated' silicosis caused by short periods of high levels of exposure.

Breathing in silica dust can also cause other serious diseases, such as:

• lung cancer
• kidney disease
• autoimmune diseases, such as scleroderma
• chronic obstructive pulmonary disease (COPD)

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 average airborne concentration of a particular substance allowed over an 8-hour working day, 5-day working week. For people working extended shifts, the TWA will need to be adjusted.

The workplace exposure standard for respirable crystalline silica is based on the levels found in a person’s breathing zone, outside of any respiratory protective equipment (RPE) that may be in use.

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

WorkSafe recommends that employees are not exposed to levels above 0.02 mg/m3 as an 8-hour TWA. This is a precautionary measure to minimise the risk of silica-related disease such as silicosis and lung cancer. For more information, see WorkSafe’s guidance, Exposure standards and atmospheric monitoring.

Crystalline silica processes

Crystalline silica processes are defined under regulation 319B of the OHS Regulations and include a wide range of activities.

Stonemason work often involves crystalline silica processes, such as the use of a power tool or other mechanical plant to:

• cut, grind, polish or crush material containing crystalline silica, or
• carry out any other activity involving material containing crystalline silica that generates respirable crystalline silica dust

For example, using a power tool to cut, grind or polish a marble, sintered stone or porcelain benchtop is a crystalline silica process.

High risk crystalline silica work

High risk crystalline silica work 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

All engineered stone work is now considered HRCSW. For information on permitted work with engineered stone, see WorkSafe's guidance, 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 doing a risk assessment or by choosing to identify that the work is HRCSW without doing a risk assessment.

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

• the specific tasks or processes required to be undertaken with material that contains crystalline silica
• the form of crystalline silica to be used
• 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

An employer or self-employed person must not perform HRCSW unless a crystalline silica hazard control statement is prepared before the work commences, and the work is performed in accordance with that crystalline silica hazard control statement.

A crystalline silica hazard control statement is a document that sets out the hazards and risks arising from HRCSW, details the measures to control those risks and how they will be implemented and the results of certain sample analyses.

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

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) and Part 4.5 (Crystalline silica) 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, choosing to work with products with lower silica content such as sintered stone instead of granite
• 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 remains after the listed risk control measures have been implemented, administrative controls, such as rotation during shifts between high and low exposure tasks, must be used to reduce the risk so far as is reasonably practicable.

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

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

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 WorkSafe's guidance, Working with engineered stone.

Consultation

Employers must consult, so far as is reasonably practicable, with their employees, including independent contractors, on certain matters related to health and safety that directly affect or are likely to directly affect them. For example, when they are identifying or assessing hazards or making decisions about measures to control risks associated with crystalline silica exposure. If employees are represented by a health and safety representative (HSR), the consultation must involve that HSR, with or without the direct involvement of the employees.

Integrated water delivery system

An integrated water delivery system, also known as on- tool water suppression, is one of the most effective ways to reduce exposure to crystalline silica dust.

Water suppression uses water at the point of dust generation to dampen down or suppress dust before it is released into the air. WorkSafe views this control as reasonably practicable in most situations.

Water recycled onsite for use in water suppression needs to be effectively filtered to remove crystalline silica particles and prevent contaminated water continually passing through the system with an increasing crystalline silica concentration.

Water that is recycled needs to be visually assessed to ensure it is clear. If the water has a cloudy or milky appearance, this means it is likely to contain a high concentration of crystalline silica and creates a risk that respirable particles will be released into the air.

On-tool dust extraction

Another effective way to reduce exposure to crystalline silica dust is to use on-tool dust extraction, which removes the dust from the source as it is being produced. An extraction device is fitted directly onto the tool and attached to a high efficiency particulate air (HEPA) filtered Dust Class M or H vacuum cleaner.

A H-class vacuum is more efficient than an M-class vacuum and should be used if reasonably practicable to do so.

Local exhaust ventilation

Local exhaust ventilation (LEV) means an engineering control that captures the emission of an airborne contaminant at its source and transports it to a safe emission point, filter or scrubber.

LEV systems such as hoods, booths or extraction walls extract airborne dust from processing areas. While these controls may reduce background levels of silica dust, they are not as effective as water suppression or on-tool dust extraction in reducing the exposure of employees.

Where an integrated water delivery system, on-tool dust extraction system or another LEV system is used, employers and self-employed persons must ensure those systems are designed, installed, used and maintained, so far as is reasonably practicable, to eliminate or reduce the risk of exposure to crystalline silica dust.

Respiratory protective equipment

After implementing engineering controls, if the risk of exposure to crystalline silica dust remains, an employer must provide appropriate PPE, such as RPE.

RPE needs to comply with AS/NZS 1716 – Respiratory protective devices, or an equivalent standard and is strongly recommended for working with other crystalline silica materials.

Check the product information to make sure RPE is AS/NZS 1716 compliant. If it is not clear, ask the supplier or contact the manufacturer.

RPE needs to have at least a P2 filter and it is recommended it be fit tested for each person to ensure a correct fit. RPE that requires a facial seal, such as half-face respirators, should not be used by people with beards or facial stubble. Where facial hair interferes with the fit of the RPE, a powered air purifying respirator (PAPR) that does not rely on a facial seal needs to be used, such as a PAPR with a loose-fitting hood or helmet.

RPE needs to be selected, used and maintained in accordance with AS/NZS 1715 – Selection, use and maintenance of respiratory protective equipment.

Employers need to provide employees with information, instruction and training in the use, fit and maintenance of RPE, including the system for storage.

Reducing dust

Reducing dust during installation work

Employers need to eliminate cutting at the installation site to prevent dust from being generated during installation work. Ways to do this include the following:

• Asking builders to provide a template for pre-cutting the silica-containing materials at the fabrication workshop.
• Ensuring installation measurements are correct. Using lasers may assist in taking precise measurements for off-site installations.
• Asking builders to communicate any installation changes before employees attend the site. For example, changes to location or measurements.
• When modifications are found to be necessary, directing that the slab be taken back to the fabrication workshop rather than undertaking processing at the installation site.

If it is not possible to eliminate cutting during site installation, employers must control exposure to respirable crystalline silica dust using the control measures described in this guidance.

Cleaning the work area

The work area should be cleaned after each job is completed to ensure there is no build-up of respirable crystalline silica dust on plant, equipment, working surfaces or the floor. RPE needs to be worn during clean-up activities.

Ensure clean-up and housekeeping processes don't generate dust in the air. For example, use a HEPA filtered Dust Class M or H vacuum, low-pressure hosing, mopping, squeegeeing or wet wiping down surfaces. Never use compressed air, dry sweeping or high-pressure water to clean up, as this is likely to generate airborne dust.

Bags used for containing waste need to be strong enough to ensure they will not tear and release dust. To minimise the risk of a bag tearing or splitting, bags should not be filled more than half full and excess air should be gently evacuated from the bag in a way that does not cause the release of dust.

Personal decontamination

PPE such as RPE, aprons and boots needs to be cleaned after each use to ensure dust does not accumulate. For example, by using a low-pressure hose or wiping down with wet rags. Work clothes should not gather dust if exposure is appropriately controlled during processing work. However, if dust has settled on clothing, the contaminated clothing should be dampened, bagged and labelled with 'Silica dust hazard'. Contaminated clothing should not be taken home but should either be laundered on site or sent to a commercial laundry. If a commercial laundry is used, the employer or self-employed person needs to contact the laundry to determine how it wants to receive the clothing.

Managing crystalline silica waste

Employers must control the risk of exposure to crystalline silica dust during waste management and disposal. For example, when wet slurry is collected, or dust captured by an extraction system is ready for disposal, it needs to be contained and handled in a way that minimises the release of dust. Containers of waste contaminated by silica dust must be identified, for example, by a label that clearly states 'Silica dust hazard'.

Wet slurry

Wet slurry is the waste from dust-generating processes that are water suppressed. While it is wet, the slurry is not hazardous. If it is allowed to dry, some dust may be disturbed and become airborne. If there is any risk of exposure to dust for people who may handle the waste, for example, employees, waste collectors or waste transfer station staff, the waste needs to be bagged and sealed before it is disposed.

Wet slurry needs to be managed by capture or containment through floor bunding, grading, grates, curbing and channelling. Wet slurry should not be allowed to dry and become airborne. Slurry capture systems need to be regularly inspected to ensure drains are not clogged and the system is operating effectively.
 

Information, instruction and training

Employers must provide their employees with any necessary information, instruction, training and supervision to enable them to do their work safely. This duty also extends to independent contractors, including any employees of the independent contractor, engaged by the employer in relation to matters over which the employer has control.

For example, training needs to be provided to employees on:

• crystalline silica hazards and health risks
• how to effectively use controls
• use and maintenance of RPE
• how to dispose of waste
• methods for personal decontamination

An employer must ensure that employees who are likely to be exposed to risks associated with HRCSW are given information, instruction and training in:

• the health risks associated with exposure to crystalline silica dust, and
• the need for, and proper use of, any risk control measures and how they are to be implemented

Training programs need to be practical and 'hands on'. The structure, content and delivery of the training need to consider any special requirements of the employees and independent contractors being trained. For example, information, instruction, and training may need to be provided in a language other than English.

Other considerations for how training is delivered include specific skills or experience, disability, literacy and age. Training programs should also be reviewed periodically and as required to ensure suitable information, instruction and training is provided to employees.

Refresher training needs to be provided as appropriate for the workplace. The frequency of refresher training should be determined considering the complexity of the work, the skills required and the frequency with which the tasks or work is carried out.

Employers must provide supervision to employees where supervision is necessary to enable those employees to do their work safely. This is particularly important with employees who are more vulnerable, such as new, inexperienced or young employees.

Employers must ensure that an applicant who applies for employment involving HRCSW is given information about:

• the health risks associated with exposure to crystalline silica dust
• the need for measures to control those risks, and
• details of the control measures

Atmospheric monitoring

Atmospheric monitoring, also known as air monitoring, means a procedure by which air is sampled within the breathing zone of a person to measure and evaluate the person's exposure to airborne contaminants.  

By law, employers must carry out atmospheric 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 are not required to carry out atmospheric monitoring if they are required to undertake biological monitoring as a part of health monitoring for their employees

Employers need to conduct an ongoing air monitoring program to confirm that the exposure standard for respirable crystalline silica is not being exceeded.

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
• if there are changes to the workplace exposure standard, and previous air monitoring results have indicated levels above the new standard

Air monitoring and the interpretation of results, including comparison with the exposure standard, needs to be undertaken by a person with the necessary skills, knowledge and experience, such as an occupational hygienist. The Australian Institute of Occupational Hygienists (AIOH) represents the occupational hygiene field. A list of service providers with the necessary experience to conduct air monitoring can be found on the AIOH website.

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

Where possible, air monitoring results should be shared with medical practitioners who are monitoring the health of employees. For more information, see WorkSafe's 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 the guidance Working with engineered stone.