What is Silica Dust? – Crystalline Silica

By Anthony Jenkins MAIH

Crystalline silica is found in stone, rock, sand, gravel, and clay, products such as bricks, tiles, concrete, artificial stone benchtops and some plastic materials. When these materials are worked on, silica is released as fine dust. This dust is respirable crystalline silica (silica dust)

SafeWork NSW video

Silica dust and Cancer

Uncontrolled cutting, grinding of materials containing crystalline silica presents a serious risk to health. Silica dust is harmful when breathed in, 100 times smaller than a grain of sand, you can breathe it without knowing leading to silicosis, chronic obstructive pulmonary disease, kidney disease, lung cancer. It’s estimated each year 230 people develop lung cancer due to past exposure to silica dust at work. Not all exposed workers will develop cancer, risk increases with long term or repeated high-level exposure.

 

Image Credit: https://www.svhlunghealth.com.au/conditions/silicosis

 

As of 1 July 2020, all medical practitioners must notify NSW Health when they diagnose a case of silicosis in NSW. Silicosis is a scheduled medical condition under Part 4 of the NSW Public Health Act 2010

In 2011 about 587,000 Australians were exposed to silica dust whilst working. Estimated that about 5700 of these workers will develop lung cancer over the course of their life. Greatest risk are miners, construction workers, farmers, and engineers. You may be exposed to silica dust if your work involves:

  • Breaking, crushing, grinding, milling silica-containing material
  • Sand blasting
  • Moving earth / soil, excavating, quarrying
  • Sand casting
  • Brick laying
  • Paving, concreting, re-surfacing, cement rendering
  • Road construction
  • Demolition
  • Stonemasonry
  • Manufacturing concrete pavers, tiles, castings
  • Drilling, cutting, honing, grinding, chiselling, sanding silica containing materials
  • Handling, mixing, shovelling dry silica – containing materials

 

Effective Controls

All Australian workplaces must follow work health and safety laws, these vary slightly between states and territories, but the duty of care for employers and responsibilities of workers across Australia is similar.

  • Employers are required to ensure the health and safety of their workers at their workplace.
  • Within reason, workers must take care of their own health and safety, not negatively affect that of others and follow instruction and workplace health and safety policies

Eliminate or reduce exposure to hazards by following the risk management process and using the hierarchy of control.

  • Eliminate (remove hazard completely)
  • Substitute
  • Engineering controls (exhaust, suitably rated dust extraction vacuums in conjunction with adaptive shrouds on power tools\ water suppression – wet saws) Just wetting the material is NOT enough -select the correct equipment.
  • Administrative controls (signage, operator training, planning, health monitoring, Risk assessment / Air monitoring.
  • Personal protective equipment PPE. Fit tested Dust masks

Workers must be involved in the process to correctly identify hazards, control measures that suit the workplace and task. If suitable control measures are not in place, anyone working around silica dust has an increased risk of developing lung cancer.

Workers MUST be given information on training and control measures and how to use them, information on the possible health effects of silica dust exposure and the health surveillance requirements of both employers and staff.

Air Monitoring

Mandatory limit for silica dust exposure in Australia is 0.05mg/m3 averaged over an eight (8) hour day (except Tasmania where it’s 0.1mg/m3). 0.02mg/m3 is preferred, reduces the risk of lung cancer and silicosis. Currently there is no evidence to suggest a safe level of silica dust exposure. Work Health and Safety (WHS) Regulation 50 states air monitoring (by occupational hygienist) must be conducted if there is any risk to health or there is potential of exceeding the exposure limit. Exposure levels in settings like construction sites are always changing, air sampling alone is not enough.

Breathing in this small amount of silica dust means you have exceeded the exposure limit of 0.05mg/m3

 

Health Surveillance

WHS Regulations state that health monitoring must be provided to workers who are continually working with silica dust and there is a significant risk to the worker’s health. Safe Work Australia’s crystalline silica health monitoring guide outlines how to monitor workers. Health monitoring can help to detect loss in lung function before permanent damage. Surveillance should be undertaken before job placement, at least every three years (yearly for high-risk jobs).

For any concerns related to control measures at your workplace, or for more information on the control of air quality contact:

  • Workplace supervisor or management (if you’re an employee)
  • Workplace health and safety representative or union representative
  • State and territory work health and safety regulators
  • Safe Work Australia

Prevent silica dust exposure by keeping the dust out of the air. If you think you have been exposed to a cancer-causing agent it’s important you speak with your doctor or to an experienced health professional on 13 11 20 or visit www.cancer.org.au

 

 

Anthony Jenkins MAIH is a Horticulturist, Licenced Landscaper, Landscape Designer, Teacher Landscape Design, Horticulture & Landscape Trades – PADSTOW TAFE NSW

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