Assessing and Managing Silica Dust Exposure in High-Risk Industries 

30/05/2024by admin0Read: 11 minutes

In high-risk industries such as construction, mining, manufacturing, and abrasive blasting, unchecked silica dust exposure poses a significant occupational health hazard. Hence, as a responsible employer or industry professional, it is crucial to assess and manage silica dust exposure to safeguard the well-being of workers.

In this blog, we will explore the importance of assessing and managing silica dust caused by processes in high-risk industries and discuss effective strategies for mitigating its health risks for individuals working with it.

Understanding Silica Dust

Silica is a naturally occurring mineral found in materials like sand, stone, concrete, and mortar. When these materials are cut, ground, or drilled, fine particles of crystalline silica are released into the air. These tiny particles can be inhaled, causing serious health problems over time.

High-Risk Industries in Australia

Certain industries in Australia are particularly susceptible to silica dust exposure due to their operations:

  • Construction: Activities such as cutting, sawing, and drilling concrete or masonry materials produce significant amounts of silica dust.
  • Mining: Drilling, blasting, and crushing rock in mines release respirable crystalline silica into the air.
  • Manufacturing: The production of ceramics, glass, and stone products involves processes that contribute to silica dust exposure.

Assessing Silica Dust Exposure

Effective management starts with a thorough assessment of silica dust exposure in the workplace. Key steps include:

1) Workplace Monitoring:

Regular air monitoring for silica is essential to measure the concentration of silica dust in the workplace. Personal sampling devices worn by workers provide accurate exposure data.

2) Risk Assessment:

Identify tasks and operations that generate silica dust and evaluate the exposure levels. Assess the duration and frequency of exposure for each worker.

a) Identify the Hazard

Determine which tasks and materials at your workplace produce RCS. Common sources include natural products, concrete, bricks, and various construction materials.

Assess all activities that might release RCS, such as cutting, grinding, drilling, and polishing.

b) Evaluate Exposure Levels

Conduct regular air monitoring to measure the concentration of RCS in the workplace. Use personal sampling devices to gather accurate data on worker exposure.

Review work practices and environmental conditions to understand how and when workers are exposed to RCS.

3) Health Surveillance:

Implement health surveillance programs to monitor the respiratory health of workers. Regular medical check-ups can help in the early detection of silica-related diseases.

Silica Dust Control Plan

For a PCBU, a risk assessment-based silica dust control strategy is a useful tool.

A PCBU may use it to identify all potential jobs that could expose them to silica dust and the controls that could be used to prevent or reduce that exposure.

A silica dust control strategy should take into account how to:

  1. eliminate or reduce the amount of silica dust that is produced and released into the air.
  2. prevent workers from breathing in silica dust.
  3. clean up any silica dust, slurry, or other waste produced.
  4. and decontaminate workers’ clothing, footwear, and protective equipment.

A Standard Silica Dust Control Plan should include the following details:

  1. The amount of crystalline silica in the product being used, as the higher the amount, the higher the level of silica in the dust and the greater the risk.
  2. sources of silica dust in the workplace.
  3. the dust control measures implemented for each activity.
  4. the integration of dust control measures into daily shift routines, such as toolbox talks, pre-start checks, and daily cleaning of work areas.
  5. and how air monitoring is used to determine whether the controls are working.
  6. How hazards, controls, any control failures, and instances when the occupational exposure standard has been surpassed are recorded and communicated.

When a PCBU decides to create a silica dust management strategy, it must be done so after consulting the HSR, if one exists, and the workers who will be doing the activities.

A PCBU may also give the certified medical professional conducting or overseeing health monitoring access to the silica dust reduction strategy. This will enable the licenced medical professional to locate any potential silica dust exposure source while taking into account the current management measures.

1) Assessment Methods for Silica Dust Exposure:

Accurate assessment of silica dust exposure is essential to identify potential hazards and develop effective control measures. Here are common methods used to assess silica dust exposure:

2) Personal Air Sampling:

This method involves collecting air samples near workers’ breathing zones to measure the concentration of respirable silica dust particles. Personal air sampling provides individual exposure data, helping to determine compliance with regulatory exposure limits and tailor control strategies accordingly.

3) Workplace Monitoring:

Regularly monitoring airborne silica dust levels within the workplace allows for identifying areas or tasks with elevated exposure risks. This information helps prioritise control measures and ensure their effectiveness.

4) Task-based Assessments:

Task-based assessments focus on evaluating silica dust exposure during specific job tasks or activities. By assessing factors such as duration, frequency, and proximity to dust sources, it becomes possible to pinpoint high-risk tasks and implement targeted control measures.

5) Static Monitoring

To detect background levels of respirable crystalline silica outside of a worker’s breathing zone, static or fixed position monitoring may be used at stationary locations, such as fabrication workshops.

Static monitoring entails collecting air samples from stationary points outside the area where work processes occur.

Static monitoring can be used to assess the performance of current risk controls or the design of new ones, but it shouldn’t be interpreted as a measure of real worker exposure to respirable crystalline silica.

Control Measures to Manage Silica Dust Exposure:

Once the assessment phase is complete, effective management strategies can be implemented to control silica dust exposure.

According to occupational health and safety regulations, it is your responsibility as a person conducting a business or undertaking (PCBU) to recognise risks, evaluate their severity, and put in place workable measures to safeguard the health and safety of your employees.

A PCBU is required to limit hazards associated with silica dust exposure to workers and other people at their job, or to completely remove them if doing so is not reasonably practical.

Applying the hierarchy of control measures is an excellent method to fulfil this obligation. The hierarchy lists control methods in order of decreasing amount of protection and dependability.

Some key measures to consider include:

1) Engineering Controls:

Implementing engineering controls is the most effective way to minimize silica dust exposure at its source. Examples include local exhaust ventilation systems, dust suppression methods (such as wetting down surfaces or using water sprays), and the use of enclosed or automated systems that reduce dust generation.

2) Administrative Controls:

These measures focus on work practices and procedures to minimize exposure. Examples include job rotation, limiting access to high-dust areas, scheduling high-risk tasks during low-occupancy periods, and establishing designated clean areas. 

3) Water Suppression:

Water is used to dampen or suppress dust at the source of its formation before it is discharged into the atmosphere. There are powered hand tools, huge machinery, such as bridge saws, routers, or polishing machines, as well as equipment with water feeds and grinders and polishers.

A suitable ingress protection (IP) rating for usage with water suppression should be present on any machinery or equipment utilised for water suppression.

To prevent dust from being discharged throughout the process, the water feed must be attached, and there must be enough water feeds aimed towards the tool or material. Additionally, the water feed must be operating with a constant water flow and sufficient water pressure (typically at least 0.5 L/min) should be maintained in accordance with the manufacturer’s recommendations; be equipped with guards, plastic flaps, or brush guards intended to handle the water spray or mist containing silica dust.

4) Combination of Water Suppression with other Controls

Through isolation, measures like guards, enclosures, and barriers, silica dust transported in the air or in water mist formed from water suppression may be further managed. In addition to these measures, respiratory protective equipment (RPE) and administrative controls should be implemented.

This can be achieved by:

  1. Providing separation between the work process and the worker, for example, operator positioning when using bridge saws or routers.
  2. Providing separation between workers using powered hand tools and other workers in the workplace; and
  3. Providing physical barriers between different workers and workstations to prevent the water mist from moving into other workspaces.

Regular upkeep and cleaning will assist in guaranteeing that guards continue to function efficiently.

5) Local Exhaust Ventilation (LEV)

Before airborne pollutants enter the employees’ breathing zones, LEV is made to filter the air. When sprayed close to the site of generation, it is the most efficient way to manage significant amounts of silica dust.

A suitable LEV should be installed on tools like drills, routers, saws, and other machinery. To ascertain if on-tool extraction and LEV equipment are appropriate for a certain workplace, the manufacturer can offer details on how the equipment gathers dust.

A basic LEV system typically consists of the following components:

  1. an extraction hood to catch and remove contaminated air close to the point of release.
  2. ducting to connect to an air-cleaning system.
  3. a fan to move the air through the system; and an exhaust stack outside the building to disperse the cleaned air.

While these measures may lower background silica dust levels, they are less successful in lowering silica dust exposure for employees who do high-exposure jobs. High exposure activities should be carried out utilising on-tool controls, such as integrated water suppression or dust extraction, that eliminate or collect dust at the source.

6) Natural Ventilation

Improved ventilation will help to lower the number of pollutants in the air, but additional measures must also be taken to stop the discharge of silica dust. Windows and doors should be left open to promote general ventilation, and there should be a sufficient supply of fresh air in the workspace. Fans should be placed such that polluted air streams are directed away from workers and clean air streams are drawn past the workers. Before using fans, wet slurries should be cleaned up to stop them from drying and perhaps generating a dust danger.

7) Workshop Layout

The structure of processing workshops should be planned to reduce exposure to and contamination from silica dust produced in nearby work areas.

For instance, by placing workspaces for each stage of processing in order and leaving enough space between workstations.

8) Work Practices

The production of silica dust and worker exposure can be affected by how the activity is done. The following work practices may help reduce exposure, even if the use of higher order controls such as water suppression and LEV is essential to minimise worker exposure to silica dust:

  1. Plan all stone cutting, grinding, trimming, drilling, sanding, or polishing to be done at the fabrication workshop before on-site installation.
  2. Plan stone cutting to make the fewest number of cuts possible for each job. Implement policies that specify what should be done when working with engineered stone. For instance: wetting engineered stone before cutting, grinding, trimming, drilling, sanding, or polishing to remove dust.
  3. Implement shift rotations to prevent workers from being exposed to dust for prolonged periods of time.
  4. exclude workers and others not involved with the cutting, grinding, trimming, drilling, sanding, or polishing task.
  5. implement maintenance schedules to ensure routine, or daily checks of critical controls, such as guards, LEV, and PPE.
  6. implement good housekeeping policies, such as regular cleaning of work areas; and ensure workers wash their hands.

9) Safe Work Procedures

The quantity of silica dust produced will be influenced by how the workers utilise power tools, machines, and other tools.

Workers and other people who will use the plant or equipment must get the information, training, instruction, and supervision necessary to protect them against silica dust and any other dangers associated with its usage before it is employed in the workplace.

Safe work procedures should be prepared in a way that includes guidelines on:

  1. the proper use of silica dust control equipment.
  2. how to operate the plant and equipment to reduce the generation of silica dust.
  3. how to conduct inspections, shut down, clean, repair, and maintain the plant and silica dust control equipment, emergency procedures.
  4. how to use personal protective equipment (PPE), such as protective footwear, eyewear, RPE, and aprons.

If warning signs are necessary to limit the risks of silica dust, they must be utilised to communicate the hazards of silica dust or the necessary PPE (Personal Protective Equipment).

10) Personal Protective Equipment (PPE):

While engineering and administrative controls are primary means of controlling exposure, PPE should be used as a secondary measure to provide additional protection. Respiratory protection, such as respirators with appropriate filtration for silica dust, should be provided to workers in high-risk areas.

11) Respirable Protective Equipment (RPE)

Establishing a method to control employees’ usage of RPE is a smart idea. The system should consist of the following:

  1. choosing the best RPE for the job; and fit testing.
  2. a use, maintenance, storage, and repair program.
  3. a policy against facial hair for tight-fitting respirators.
  4. and providing employees with information, training, and supervision.
a) Choosing Appropriate RPE for Silica Dust

A PCBU is responsible for making sure RPE is chosen to reduce health and safety hazards. This entails making certain the RPE:

It should also be:

  1. suitable given the nature of the work and the risks involved in it.
  2. a suitable size, fit, and level of comfort for the worker who will use and wear it.
  3. maintained, repaired, or replaced to continue to reduce risk to the user, including by making sure it is clean, hygienic, and in good working order.
  4. and used or worn by the user, to the extent that is practically possible.
b) Fit Testing

To ensure that the RPE functions well and is pleasant to wear while wearing additional PPE that may be required for the activity, fit testing is crucial. The efficiency of the seal between the worker’s face and the respirator is evaluated during fit testing. If there is a poor seal, silica dust or other contaminated air might flow into the respirator and be inhaled by the worker.

Two different fit testing procedures may be used: Quantitative and Qualitative respectively.

Quantitative testing measures how much air leaks into the respirator and is only used on half-face respirators, full-face respirators, and PAPR.

Qualitative testing is a pass/fail test that depends on the wearer’s ability to taste or smell a test agent.

Results from quantitative fit testing are more objective than those from qualitative testing since certain employees have trouble with their senses of taste and smell. This might lead to a ‘false pass’ and inadequate worker health protection.

The quantitative approach should be used to fit test full-face respirators and PAPR.

When and who should perform Fit Testing?

A competent individual, manufacturer, supplier, or consultant should do all fit testing:

  1. Before a worker puts on a tight-fitting respirator for the first time.
  2. Every time a new brand or model of respirator is given to a worker.
  3. whenever there is a change in the wearer’s facial features or characteristics that could affect the seal, such as a significant weight gain or loss, once a year.
c) Fit Checking

Fit checking is a short check to ensure that a fit-tested respirator is properly positioned on the face and that there is a good seal between the respirator and the face.

The worker is accountable for doing a fit check, and they must get training for doing so. To safeguard their health and safety, workers should do a fit check each time they use a tight-fitting respirator.

12) Other PPE

Depending on the task at hand, employees may also require various PPE in addition to respirators. To determine the PPE needed for workers, a risk assessment should be done.

The PCBU should evaluate the circumstances that might have an impact on the workers’ health and safety.

Before beginning any work creating silica dust, make sure proper PPE and training are supplied.

Other types of PPE that may be used to reduce exposure to silica dust include:

  1. protective clothes, such as waterproof overalls or an apron.
  2. Eye protection.
  3. Gloves.
  4. protective footwear, such as rubber boots or gumboots.

Workers’ clothes will be protected from silica dust, including water and mists containing dust, by wearing the proper protective footwear and clothing. Keep in mind that utilising high-speed power tools might present an entanglement risk when wearing gloves.

To control additional dangers, it is advised to use a hard helmet and hearing protection.

It’s crucial to check that the PPE you choose won’t hinder the efficiency of RPE when choosing other forms of PPE.

13) Combination of Controls

When working with engineered stone, a variety of control measures, including as isolation, engineering controls, work practises and procedures, and PPE, should be employed to reduce the danger of silica dust exposure. For the length of the activity, RPE should be offered and worn properly to manage any lingering dust. A PCBU may be in violation of WHS rules if it uses only one control measure.

14) Training and Education:

Proper training and education are crucial to ensure workers understand the hazards associated with silica dust exposure, know how to use control measures effectively, and are familiar with the proper use of PPE. Regular refresher training can reinforce safe work practices and ensure ongoing compliance.

15) Regular Evaluation and Review:

Silica dust exposure management should be an ongoing process. Regular evaluation of control measures, monitoring of exposure levels, and review of workplace practices are necessary to identify any gaps or areas for improvement.

16) Practical Controls for Crystalline Silica Dust Exposure

  1. If crystalline silica is found during sample testing, your first course of action should be to remove it and replace it with another substance.
  2. If replacement is not a possibility, silica dust-producing operations like drilling and cutting should be minimised.
  3. As a last option, you should regulate any dust produced to reduce exposure and ensure that everyone at risk of exposure is wearing personal protective equipment (PPE).

New Silica Dust Regulations

The WHS Regulation 2011 has been amended in response to comments from the industry:

According to the new amendment, silica management measures must be taken into account as a minimum for silica dust. These consist of:

  1. Wet dust suppression, uses a variety of wet techniques, including misting, spraying, misting, foaming, pastes, and fluids other than water.
  2. Workers handling silica dust should be isolated from others.
  3. Respiratory protection equipment (RPE).
  4. Local exhaust ventilation.
  5. Tool dust extraction.

If you aren’t able to completely eradicate silica dust from your job by 1 November 2022, you should:

  1. When changing silica-containing materials, use a continuous flow of water over the cutting area in addition to one additional silica control method and RPE.
  2. Spray water over the cutting area continuously.
  3. A dust suppression approach plus one other silica management strategy should be utilised in cases when this is not practical.
  4. Where this is not feasible, silica control measures should be combined with tool dust extraction.
  5. One silica control measure plus RPE may be employed in cases when this is not realistically possible.
  6. In other cases, just a wet suppression technique, tool extraction, or a fully enclosed cabin may be utilised.

Violations can occur when there is non-compliance.

  1. At least one silica control measure must be in place for SCM.
  2. For people who work with crystalline silica materials, the ACT mandates training.

Anitech’s experienced occupational hygienists can help you create a robust plan to eliminate or minimise silica dust proportions at your workplace. They will also assist your organisation in silica dust exposure prevention and handling jobs involving engineered stone in a safe way as per the regulations.

Call us now at 1300 802 163 or email us at sales@anitechgroup.com


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