Silica, also called silicon dioxide, is a widespread mineral that occurs naturally and is found in mortar, concrete, sand and stone. Silica is manufactured in benchtops, tiles, bricks and some plastics. Most soils and rocks are largely made up of quartz, the most common form of crystalline silica. Silica dust is often generated through mechanical processes, including sawing, drilling, cutting, crushing and grinding.

Crystalline silica is most hazardous to workers when dust is produced, becomes airborne and inhaled. Due to the health defects that crystalline silica can cause, there is legislation in place to maintain and protect workers’ health. Workplace health and safety (WHS) standards states that silica dust levels are not to exceed the workplace exposure standard (WES).

16 December 2019 revised Workplace Exposure Standards for Airborne Contaminants

In November, the Safe Work Australia (SWA) meeting concluded that the exposure standard for respirable crystalline silica (RCS) be reduced from a time weighted average (TWA) of 0.1mg/m3 to 0.05mg/m3. On 16 December 2019, the revised Workplace Exposure Standards for Airborne Contaminants was published which included the change to exposure standard. The date of implementation for different jurisdictions is listed in the publication, with only two states currently listed. As of 17 December 2019, these two states are:

  • Victoria: 17 December 2019
  • South Australia: 1 July 2020

By the date listed above, these jurisdictions are legally obliged to ensure employees are not exposed to more than TWA 0.05mg/m3.

For those jurisdictions not yet listed, dates of implementation will be confirmed by their WHS regulator in due course. However, there is no reason why every PCBU cannot start immediately working towards complying with the new WES.

TWA is based on an eight-hour workday and the PCBU must adjust the standard if these hours are exceeded. Exposure standards are a guideline based on research of unhealthy inhalation of crystalline silica. However, natural biological variation means that employees may still experience adverse health effects below the standard from exposure to RCS.

Air monitoring must be conducted if there is suspicion the workplace contains high levels of the substance that exceeds the WES.

What control measures can be introduced into the workplace?

To decrease the risk of exposure in the workplace, a range of preventative measures are recommended. Start with identifying the activities and materials your workplace uses that may generate or contain crystalline silica. These methods should be implemented across each task stage involving silica, including the preparation, application and clear up of materials.

Some simple methods to minimise silica dust exposure are:

  • Reading the safety data sheet (SDS) and labels of products to identify quartz
  • Isolating the hazard to designated work areas
  • Substitution
    – Swapping sand for metallic shot, grit or slag products in abrasive blasting
    – Using composite stone with less silica in bench tops
  • Engineering controls using;
    – An industrial vacuum cleaner or wet sweeping to clean up dust
    – Routers and drills with dust collection bags
    – Tools with a water attachment fitted to suppress dust (on scabbling picks, power saws and jack picks)
    – Fitting large equipment (bulldozers and excavators) with air-filtering cabs
    – Wetting down dusty work spaces
  • Personal protective equipment (PPE)
    – Half-face, P1 or P2 (particulate) respirator – must be clean-shaven to be effective
    – Airline respirators should be used in abrasive blasting
    – Clothing that does not collect dust easily

Apply more than one control method where possible and employ a health surveillance program to monitor workers’ health.

Crystalline silica health surveillance in Australia

Australia’s leading occupational health bodies recognise that our construction, mining and masonry workers are among those most at risk. Workers require a medical examination at entry and exit to silica work, and annually for the duration of exposure. The purpose of annual surveillance as a preventative measure is to monitor any changes indicating lung deterioration caused by silica exposure.

The Safe Work Australia Crystalline Silica medical includes:

  • Respiratory medical and occupational exposure history
  • Medical examination
  • Spirometry (lung function) test
  • Medical review and sign off
  • Chest X-ray (ILO standard)

Crystalline silica health surveillance in Queensland mines and quarries

In 2017 the Queensland Department of Natural Resources, Mines and Energy (DNRME) introduced health monitoring guidelines for mine and quarry workers. Health surveillance should be conducted at entry and exit to crystalline silica work, and at least every 5 years during dust exposure. Baseline and subsequent test results are recorded so that any silica-caused deterioration to lung function can be identified and addressed.

The Queensland Respirable Crystalline Silica (RCS) medical includes:

  • Respiratory medical and occupational exposure history
  • Medical examination
  • Spirometry (lung function) test
  • Medical review and sign off
  • Chest X-ray (ILO standard)

How can KINNECT help?

Establishing periodic monitoring for workers that encounter crystalline silica is an important preventative measure. This ensures you are meeting your duty of care to keep your workers healthy, safe and productive.

At KINNECT, we offer RCS medicals for mine and quarry workers, and the SWA crystalline silica medical. These follow the respective state department and national guidelines. It is important to note that RCS and SWA medicals have different paperwork requirements as listed below.

References

  1. Safe Work Australia 2019 Workplace exposure standards for airborne contaminants
  2. RCS Medical Paperwork
  3. SWA Medical Paperwork
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