Silica - What you need to know
What is Silica?
Silica is silicon dioxide, a naturally occurring and widely abundant mineral that forms the major component of most rocks and solis.
Where is it found?
Silica Dust is most commonly found in rock, some stone, gravel, sand and clay. The most common form for Silica Dust is quartz and it can also be found in the following products:
High-risk work activities
Examples of work activities that can generate Silica Dust particles include:
- Fabrication and installation of composite (engineered or manufactured) stone countertops
- Angle grinding, jackhammering and chiselling of concrete or masonry
- Excavation, earth moving and drilling plant operations
- Paving and surfacing
- Mining, quarrying and mineral ore treating processes
- Construction labouring activities
- Brick, concrete or stone cutting: especially using dry methods
What are the risks?
- can develop after a short exposure to very high levels of silica dust, within a few weeks or years, and causes severe inflammation and an outpouring of protein into the lung
- can develop after exposures of 3 to 10 years to moderate to high levels of silica dust and causes inflammation, protein in the lung and scarring of the lung (fibrotic nodules)
- can develop after long term exposure to lower levels of silica dust and causes fibrotic nodules and shortness of breath
- can include progressive massive fibrosis where the fibrotic nodules in the lung aggregate
- lung cancer, kidney damage, scleroderma
The workplace exposure standard
The workplace exposure standard for respirable crystalline silica that must not be exceeded is 0.1 mg/m3 (eight-hour time weighted average).
PCBUs should keep worker exposures to respirable silica dust as low as reasonably practicable. Air monitoring will need to be conducted If there is any doubt that the exposure standard is being exceeded or to find out if there is a risk to a worker’s health
Who is responsible for managing the risk?
Work Health and Safety Act 2011
The Work Health and Safety Act 2011 (the WHS Act) provides a framework to protect the health, safety and welfare of all workers at work. It also protects the health and safety of all other people who might be affected by the work.
All workers are protected by the WHS Act, including:
- apprentices and trainees
- work experience students
- employers who perform work.
The WHS Act also provides protection for the general public so that their health and safety is not placed at risk by work activities.
The WHS Act places the primary health and safety duty on a person conducting a business or undertaking (PCBU). The PCBU must ensure, so far as is reasonably practicable, the health and safety of workers at the workplace. Duties are also placed on officers of a PCBU, workers and other persons at a workplace.
All duties under the WHS Act are qualified by the term 'reasonably practicable'.
The WHS Act also sets out the requirements for the following:
- incident notification
- consultation with workers
- issue resolution
- inspector powers and functions
- offences and penalties.
Australian and other standards (Safe Work Australia) - Information sheets providing general guidance for duty holders on Australian and other Standards and how they interact with the model Work Health and Safety (WHS) Act and WHS Regulations.
Selecting the means for controlling the risk
Where it is not reasonably practicable to eliminate the risks of RCS, the Hierarchy of controls is to be used.
Each of the higher order controls must be considered and exhausted before concluding that PPE is used to control exposure.
According to the Royal Australian College of Physicians (RACP), health assessments should include:
- Gas transfer, also called diffusing capacity of the lungs for carbon monoxide (DLCO)
- ILO chest x-ray
- Spirometry and DLCO are lung function tests.
- Records must be kept for a period of 30 years from the day a document was made:
- An air monitoring result (WHS Regulation Section 50). These records for respirable dust and silica must be readily accessible to those workers who have been exposed to the silica dust
- A health monitoring report (WHS Regulation Section 378). The period here is for at least 30 years after the record is made, but it may be longer
- Seek advice from an Occupational Hygienist.
Disposal of Materials
You can reduce the amount of dust via waste by:
- Bagging all types of debris and empty cement bags before throwing them in the bin or skip
- Keeping bins and skips outdoors when possible
- Using water misting to keep all waste material damp when possible