Understanding Crystalline Silica

For over 40 years Yarrabee and Castlemaine Stone have and continue to supply natural stone products.  Yarrabee & Castlemaine Stone do not supply engineered stone.  Yarrabee’s natural stone products do contain crystalline silica.  It is a naturally occurring and one of the most abundant minerals in the world. 

A crystalline silica containing substance is defined as any substance that:

1. contains more than 1% crystalline silica; and
2. is reasonably likely to be mechanically processed at a workplace; and
3. is not in a respirable form

Yarrabee & Castlemaine Stone’s products are not hazardous in their solid form. 

It is important to be aware of the potential hazards associated with working with crystalline silica substances. When these substances are mechanically processed, such as through cutting or grinding, dust containing crystalline silica can be generated. Exposure to this dust over a long period of time at low to moderate levels, or short periods at high levels, can result in serious health issues, including silicosis. Silicosis is a progressive and irreversible lung disease that can cause disability and death. The level of risk depends on various factors, including the percentage of crystalline silica in the material, the conditions and sites of exposure, and the activities that lead to the release of silica dust.

The workplace exposure standard for respirable crystalline silica (silica dust) must not exceed is 0.05mg/m3 (an eight-hour time weighted average).  Persons conducting a business or undertaking should keep worker exposure to silica dust as low as reasonably practicable. Air monitoring must be conducted if there is any uncertainty that the exposure standard is being exceeded, or to find out if there is a risk to a worker’s health.

Elimination is the most effective way to mitigate the risk.  Where that is not possible, the following control measures should be implemented (in order of level of impact):

1. Substitution – Choosing a substance with less hazardous form of crystalline silica.
2. Isolation – Isolating the hazard.
3. Engineering controls – implementing a control to take away the hazard such as dust extracting or wet cutting
4. Administration controls – last level controls such as good clean up processes, shift rotations, avoiding a build up of dust on surfaces.  Never use compressed air, dry sweeping, or high-pressure water to clean up as this is likely to generate airborne dust. 

A suitable form of PPE should always be worn when potential exposure to crystalline silica exists.  This includes respiratory protective equipment (at a minimum of a P2 efficiency half face respirator, or powdered air purifying respirator (PAPR))

For more information on silica dust please visit https://www.worksafe.vic.gov.au/crystalline-silica

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