Construction: Preventing exposure to crystalline silica dust
This guidance is to provide information on hazard identification and the control of risks of exposure to crystalline silica dust in construction.
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.
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.
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.
Effective dust controls, such as on-tool water suppression or on-tool dust extraction, need to be used when cutting, grinding, crushing, drilling or demolishing materials containing crystalline silica.
On tool water suppression
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 or suppress dust before it is released into the air. This is an effective control when the resultant slurry is managed and cleaned up in a manner that does not generate dust. Slurry needs to be managed so it does not dry out.
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. This is a type of local exhaust ventilation (LEV).
An on tool dust extraction system needs to:
be fitted directly onto the tool, and
be connected to a Dust Class M or H vacuum or another system that captures any dust generated by the power tool
When the unit is full, it must be emptied in a controlled manner that does not release airborne dust.
LEV systems require proper design, installation, use and maintenance to ensure dust is effectively captured at the source.
The work area should be cleaned after each job is completed to ensure there is no build-up of crystalline silica dust on plant, equipment, working surfaces or the floor.
Ensure clean-up and housekeeping processes do not spread or release dust into 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.
RPE must be designed to protect the wearer from the inhalation of airborne contaminants and comply with AS/NZS 1716:2012 - Respiratory protective devices, or requirements equivalent to that Standard.
Check the product information to make sure RPE is AS/NZS 1716 or an equivalent standard. If it is not clear, ask the supplier or contact the manufacturer.
RPE needs to have at least a P2 filter and 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 loose fitting helmet.
RPE needs to be selected, used and maintained in accordance with AS/NZS 1715 - Selection, use and maintenance of respiratory protective equipment.
If RPE is used to control risks from exposure to crystalline silica dust, employers need to provide employees with information, instruction and training in the use, fit, and maintenance of RPE, including the system for storage.
Personal protective equipment (eg RPE, boots) should 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 use a commercial laundry. If a commercial laundry is used, talk to them first about how they want to receive the clothing.
Employers must control the risk of exposure to crystalline silica dust, this includes 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'.
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.
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.
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.