Respirable crystalline silica in the stone benchtop industry

Safe Work Australia has published workplace exposure standards for airborne contaminants. The exposure standard for respirable crystalline silica 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 permitted over an 8-hour working day and 5-day working week. You can read this guide to help you interpret the standard.

Watch this short video that explains the reduction to the workplace exposure standard for respirable crystalline silica, which came into effect in Queensland on 1 July 2020.

You can also order copies of the Reduction in workplace exposure standard for respirable crystalline silica brochure (PDF, 0.72 MB).

Air monitoring involves measuring the level of RCS in the breathing zone of workers by using a personal sampler during the course of their usual shift activities (including routine breaks). Air monitoring is important to:

• check the effectiveness of control measures
• ensure the workplace exposure standard is not being exceeded at the workplace
• help choose the right level of respiratory protection
• inform health-monitoring requirements.

Air monitoring results must be kept for 30 years after the record is made and be readily available to those who may be exposed to the substance or mixture in the workplace.

According to work health and safety laws, you must carry out air monitoring if:

• there’s uncertainty, on reasonable grounds, whether the airborne concentration exceeds the exposure standard, or
• monitoring is necessary to determine whether there is a risk to health.

Some businesses and industries, such as the stone-benchtop industry and coal-fired power stations, have specific air monitoring requirements that are outlined in the codes of practice:

• Managing respirable crystalline silica dust exposure in the stone benchtop industry (PDF, 0.91 MB)
• Managing respirable dust hazards in coal-fired power stations (PDF, 0.88 MB) .

These codes specify when you must carry out air monitoring, who qualifies as a competent person to do the monitoring, and what to include in reports.

Under the Work Health and Safety (WHS) Regulation 2011, you may need to monitor the health of your workers if there is a significant risk to their health because of exposure to RCS. Find out when health monitoring may be required.

Health monitoring identifies any changes to the health of workers resulting from exposure to RCS. However, it does not protect workers against exposure to RCS or from acquiring a disease from exposure.

Health monitoring must be done or supervised by a doctor with experience in health monitoring. Any doctor who is a fellow of the Australasian Faculty of Occupational and Environmental Medicine will have the necessary experience.

Find a list of suitable practitioners.

Schedule 14 of the WHS Regulation lists what type of health monitoring is required as a minimum. Make sure your doctor provides the following tests:

• demographic, medical, and occupational history
• records of personal exposure
• standardised respiratory questionnaire
• standardised respiratory function test, for example, FEV1, FVC, and FEV1/FVC
• a chest X-ray, full PA view (taken from back to front), taken and read consistent with International Labour Organisation guidelines.

Your doctor might also suggest other tests if these tests provide an equal or better standard than the Regulation requires, for example a high-resolution computed tomography (HRCT) as a screening tool.

Once health monitoring is complete, you must obtain a health-monitoring report from the doctor and give each worker a copy of their report. You may also need to give a copy to the regulator if:

• there is any advice from the doctor that indicates that a worker may have contracted a disease, injury or illness as a result of carrying out work with RCS, or
• if the doctor recommends any remedial measures, such as a review of dust controls or the provision of a particular type of respirator.

You can email the report to AOHHU@oir.qld.gov.au, or mail it to:

Occupational Health and Hygiene Unit
Workplace Health and Safety Queensland
PO Box 820
LUTWYCHE  QLD  4030

Note: You must send WHSQ a copy of the health monitoring report even if WorkCover Queensland has been notified.

You can also refer to:

• more information about health monitoring, including, types of monitoring, payment, and monitoring reports
• a health-monitoring guide for people conducting a business or undertaking (PCBUs).

The first step is to identify respirable dust hazards. The following examples give an indication of the varying levels of crystalline silica in different products:

• engineered stone: up to 95%
• sandstone: 70–90%
• concrete, mortar: 25–70%
• brick: up to 30%
• granite: 20–45%
• fibre cement sheets: 10–30%
• demolition dust: 3–4%
• marble: 2%

You can check safety data sheets and other information from suppliers to find out whether products contain crystalline silica.

Identify where and how dust from these products is being released at your place of work. This can be done in a number of ways, including:

• Inspecting your business
  • Walk through your place of work. Observe work practices and inspect plant and equipment, and workplaces surfaces. Consider whether tools and machinery are being used correctly and with controls in place and take note of any issues that could contribute to risk.
• Talking to your workers
  • Your workers will have insight into how work is done and where risks might be. You could conduct a confidential survey to identify issues and gather ideas. Think about ways to include workers who are less likely to speak up in a group.
  • According to work health and safety laws, you must consult with workers who are, or are likely to be, affected by RCS dust exposure. If workers are represented by a health and safety representative, you need to include them in the consultation.
• Reviewing available information
  • Read through the relevant codes of practice for ideas and guidance on how to create a healthy and safe place of work.
  • Review safety data sheets, technical data sheets, product information and reputable internet resources on how to manage dust from work processes.
  • Gather information from a range of sources and find out how other places of work are managing respirable crystalline silica.

Next, you’ll have to assess the level of risk posed by RCS so you can choose the best way to control risks. Record your risk assessment and document the control measures you put in place. You can use Appendix 2 in the Managing respirable crystalline silica dust exposure in the stone benchtop industry code of practice (PDF, 0.91 MB) as an example.

Read the How to manage work health and safety risks code of practice 2021 (PDF, 0.65 MB) for more advice on how to assess and manage risks at work.

Air monitoring is essential to find out how much RCS is in the workers’ breathing zone. If you work in the stone benchtop industry, section 6.2 of the stone benchtop industry code of practice (PDF, 0.91 MB) has more information about when and how air monitoring is needed and how long you have to keep records. For guidance on air monitoring in coal-fired power stations, see section 5 in the code of practice for coal-fired power stations (PDF, 0.87 MB).

Control measures can be ranked from the highest level of protection and reliability to the lowest. This ranking is known as the hierarchy of control. You should always aim for the highest level of control, which is to eliminate a hazard and the associated risk. If this isn’t reasonably practicable, you should minimise the risk by using one or more of the following approaches:

• Substitution: replace a hazardous process or material with one that is less hazardous, for example vacuuming instead of sweeping, and using products with less crystalline silica content.
• Isolation: separate the workers from the hazard and work areas, for example install barriers to contain overspray from water-suppressed tools and equipment.
• Engineering controls: these are physical controls, including mechanical devices or processes that eliminate or minimise dust (wet or dry), such as local exhaust ventilation (including on-tool extraction), and/or water suppression.

If a risk remains, it must be minimised by:

• Administrative controls: work methods or procedures that are designed to minimise exposure, for example:
  • implement plans to routinely clean the work area and vacuum any residual dust from clothing
  • rotate workers’ tasks to reduce individual exposure time
  • schedule tasks to less busy times to reduce potential exposure to other workers.
• Personal protective equipment: provide workers with, and train them in the use of, personal protective equipment (PPE), for example, respiratory protective equipment (RPE), such as powered air-purifying respirators.

Administrative control measures and PPE rely on human behaviour and supervision. If used on their own, they tend to be least effective in minimising risks.

Always use a combination of control measures to manage the risk of RCS. For example, use water suppression and/or local exhaust ventilation system together with respiratory protective equipment.

See below for more advice about specific control measures and refer to the How to manage work health and safety risks code of practice 2021 (PDF, 0.65 MB) for more practical guidance on how to develop effective controls in your place of work.

According to the WHS Regulation you must review control measures :

• if the control measure doesn’t control the risk, for example, if:
  • the results of monitoring show that the control measure does not control the risk
  • a notifiable incident occurs because of the risk
• before a change at the workplace that is likely to give rise to a new or different risk that the current measure/s may not effectively control
• if a new relevant hazard or risk is identified
• if the results of consultation indicate that a review is necessary
• if a health and safety representative requests a review
• if there are changes in a safety data sheet, for example, a product composition change, or a variation in the workplace exposure standard for silica
• if air-monitoring results exceed the 0.05mg/m³ (8h TWA) workplace exposure standard for RCS
• if a health-monitoring report indicates a worker has a disease or illness, for example silicosis, progressive massive fibrosis, chronic obstructive pulmonary disease, lung cancer or emphysema, that is the result of RCS exposure
• in response to any recommendation made by the registered medical practitioner to improve dust control measures.

Control measures must be reviewed at least once every 5 years.

Find ways to eliminate or minimise RCS dust in the place of work. Consult with clients, designers, suppliers and workers if necessary. You can stop or reduce dust by:

• ordering the right size of building materials to minimise cutting and preparation
• using products with a lower crystalline silica content
• using fibre cement sheet sheers instead of circular saws
• housekeeping – avoid dry sweeping where possible as it releases dust into the air. If it has to be done, make sure workers wear suitable respiratory protection. Alternative cleaning methods include:
  • wet sweeping
  • hosing down/wiping/mopping of surfaces
  • vacuuming up dust and debris containing silica using an H-class vacuum cleaner that complies with AS/NZS 60335.2.69:2017. An M-class vacuum cleaner is also suitable for the construction industry
  • using ride-on floor cleaners (HEPA filtered or water scrubbing)
• waste disposal – you can reduce dust associated with waste by:
  • bagging waste materials before putting them into the bin or skip
  • locating bins and skips outdoors where possible
  • using water misting systems to keep waste materials damp where possible.

If it’s not practical to eliminate or substitute work processes or materials containing RCS, use engineering controls such as local exhaust ventilation (LEV) or water suppression to minimise dust exposure and provide workers with suitable respiratory protection. Common control options are listed below.

On-tool extraction

This method removes dust as it’s being produced. It’s a type of LEV-system that fits directly onto the tool, with a capture hood, tubing, and a M-or H-class dust-extraction unit or vacuum, depending on the industry you work in.

Water suppression

You can use water or fine mist to suppress dust. This method needs to be used correctly with enough water applied the whole time that work is being done. Just wetting the material beforehand doesn’t work. Examples are wet cutting methods for brick, tile, stone and concrete.

Isolation

Try to isolate areas where dust is being produced. Fully enclosed operator cabins, like those on earthmoving plant, have been shown to effectively minimise exposure to RCS when fitted with properly designed and maintained HEPA air filtration.

If you can, locate RCS work processes outdoors and away from other workers. If the work’s done indoors, use isolation controls to separate the process from other work areas, for example, enclose the immediate area with plastic sheeting from floor to ceiling.

RPE should be used in combination with other control measures such as LEV or water suppression.

No respirator can fully prevent the risk of airborne RCS being inhaled. It’s important to choose the right respirator for the job and to make sure it fits correctly, and is comfortable. Think about the amount of time workers will wear the respirator—will it be effective and comfortable during this time?

You should select RPE in accordance with AS/NZS 1715:2009 Selection, use and maintenance of respiratory protective devices.

Read more about selecting and maintaining RPE.

Watch a video on how RPE was used to successfully control exposure to RCS.

This section lists appropriate control measures and personal protective equipment for particular power tools.

Hand-held power saws, wall chasers, core drills, rotary hammers, chisels, breakers, hand-held grinders (cutting/grinding), walk-behind floor grinder

Control methods:

• Local exhaust ventilation (also called dust extraction)—fit tools with a suitable collection hood and an H-class extraction unit or vacuum. M-class is also suitable for the construction industry. Make sure the extraction flow rate is right for the work and that hose connections are tight and secure without obvious leaks.
• Water suppression—use tools that have dedicated water suppression. Make sure the water supply is sufficient for the task and that slurry is controlled and cleaned up before it dries out.
• Personal protective equipment—use a respirator with at least P1 filtration, fit-tested to the worker if they’re using a tight-fitting half-or full-face mask.

Stationary brick saws, walk-behind saws, quick-cut saws

Control methods:

• Water suppression—use saws with dedicated water suppression. Make sure the water supply is sufficient for the task and that slurry is contained and cleaned up before it dries out.
• Personal protective equipment—respirator with at least P1 filtration, fit-tested to the worker if they’re using a tight-fitting half-or full-face mask.

Hand-held drills

Control methods:

• Local exhaust ventilation—use either:
  • a tool-mounted HEPA-filtered dust collector, or
  • an on-tool capture hood connected to a dust extractor/vacuum rated to either M-or H-class in accordance with AS/NZS 60335.2.69 (Note: H-class only for stone-benchtop fabrication and installation). Use a vacuum rated to either M-or H-Class in accordance with AS/NZS 60335.2.69 when cleaning holes.
• Personal protective equipment—respirator with at least P1 filtration, fit-tested to the worker if they’re using a tight-fitting half-or full-face mask.

The workplace should be cleaned regularly to stop the build-up of dust on floors, walls, other surfaces, and equipment.

To minimise dust while cleaning up:

• use low pressure water, wet sweeping or an H-class rated vacuum cleaner to clean floors, walls and other surfaces. An M-class vacuum cleaner is also suitable for clean-up in the construction industry
• avoid using dry sweeping or compressed air to clean surfaces or clothing (Note: these are not permitted for stone benchtop fabrication and installation)
• dispose of waste products in a way that minimises the redistribution of dust (e.g. covered, kept wet, or bagged).

Managing wet slurry

Wet slurry is the waste that’s produced when dust-generating processes are water supressed. While it’s not hazardous when it’s wet, once it dries out, the dust can become airborne and expose workers to respirable crystalline silica.

Wet slurry must be managed by:

• capturing or containing it
• keeping floors and surfaces wet
• regularly cleaning, including at the end of each task or day, to prevent wet slurry drying.

Recycled water

Recycled water used to suppress dust must be effectively filtered to remove RCS particles. Without an appropriate filtration system, there’s a risk that continual recycling will increase the concentration of RCS in the water and therefore the level of RCS in the mist from the water-suppression activities .

Regularly clean any PPE and clothing worn at work to remove any dust containing RCS.

Maintain, repair or replace PPE to make sure it continues to be effective. A maintenance program should include daily cleaning and inspection of PPE by the worker for wear and damage, and identification and repair or replacement of any worn or defective components or equipment.

In some circumstances, your employer may have to provide health monitoring. Health monitoring is used to detect changes to your health because of exposure to silica.

Health monitoring may involve:

• talking to a doctor with experience in health monitoring about the type of health tests you should have and how often you should have them
• answering the doctor’s questions about your work history, medical history, lifestyle (for example diet), and smoking and drinking habits—some of these things can change how your body responds to a hazardous chemical
• a physical examination
• tests of your lung function (spirometry tests)
• X-rays and in some cases a high-resolution computerised tomography (HRCT) scan.

Respirable crystalline silica can cause serious illness and disease, so it’s important to participate in health monitoring. Your employer must:

• talk to you about health-monitoring requirements and choosing a registered medical practitioner
• provide you with a copy of the health-monitoring report.

If you’re reluctant to take part in health monitoring, talk to your employer and personal doctor about your concerns. Early diagnosis and treatment can prevent more serious and life-threatening conditions from developing.

You can read more information about health monitoring and also refer to Safe Work Australia’s health-monitoring guide for workers

Health monitoring involves monitoring a worker’s health to identify any changes resulting from exposure to hazardous chemicals at work. Health monitoring required for RCS under the Regulation includes:

• demographic, medical and occupational history
• records of personal exposure
• standardised respiratory questionnaire to be completed
• standardised respiratory function test, for example, FEV1, FVC and FEV1/FVC
• chest X-ray full size PA view.

The PCBU might require other testing to meet the industry-specific code, for example, the code of practice for:

• managing respirable crystalline silica dust exposure in the stone benchtop industry (PDF, 0.91 MB)
• managing respirable dust hazards in coal-fired power stations (PDF, 0.88 MB).

You should prepare a health monitoring program in consultation with the PCBU. A program needs to be specific to the worker and specific to RCS exposure. You can recommend another type of monitoring if it’s as good, or better, than those listed above, for example:

• high-resolution computed tomography (HRCT)
• measuring the diffusing capacity of the lungs for carbon monoxide (DLCO).

You must also complete a health monitoring report and provide it to the PCBU .

Before agreeing to supervise or carry out a health monitoring program, make sure you have the necessary skills, qualifications, and experience. You need to be able to:

• plan a health monitoring program specific to the type of hazardous chemical workers are exposed to, in this case RCS
• implement, monitor, and manage a health monitoring program
• recognise and harness specialist assistance when required
• source, interpret, and apply best-practice, medical, toxicological, and epidemiological literature, and integrate this knowledge into health monitoring programs
• advise and supervise other registered medical practitioners who are carrying out health monitoring.

For more detailed information about health monitoring generally, refer to the health monitoring guide for registered medical practitioners. Read the guideline for assessing engineered-stone workers exposed to silica (PDF, 0.25 MB) for more information about assessing the respiratory health of a worker who’s exposed to respirable crystalline silica from engineered stone .