WorkSafe has completed 92 unannounced inspections of stone suppliers and manufacturers since Victoria’s engineered stone ban took effect on 1 July. The visits have caught out a small number of duty holders, with three now referred for investigation for suspected supply and processing of engineered stone products in breach of Occupational Health and Safety Regulations.

WorkSafe’s Silica Field Team has also issued 38 compliance notices since July 1, including non-disturbance notices to prevent the supply of engineered stone products. Inspectors have additionally seized a number of samples for testing of silica content. WorkSafe Executive Director Health and Safety Sam Jenkin said regular inspections would continue to drive home the message that complying with the ban is a legal requirement – not an option.

This spike in cases is linked to a rise in the manufacturing and use of engineered stone. So what is crystalline silica and how do we protect our workforce?

What is it?

Crystalline silica is a mineral compound found in soil, rock and sand. Respirable crystalline silica (RCS) is generated by the vigorous processing of compounds that contain crystalline silica in the form of dust. Examples of processing activities are, cutting, sawing, drilling, grinding and polishing materials that contain crystalline silica. RCS particles are very small, as such they are likely to remain airborne longer than larger dust particles and are invisible to the naked eye. Compounds and the amount of RCS contained are outlined below:

• Granite
• Shale
• Natural Sandstone
• Composite
• Aggregates, mortar, concrete

What does it do?

When generated, RCS may be inhaled, lodging deep within the lungs. A number of diseases have been associated with the inhalation of RCS with silicosis being the primary disease.

Silicosis is divided into three main types:

Acute silicosis may develop after exposure to very high levels of RCS over a short period of time, within a few weeks or years. Acute silicosis causes severe inflammation and an excess protein in the lung.

Accelerated silicosis may develop after exposure to moderate – high levels of RCS over the period of 3-10 years. Accelerated silicosis causes inflammation, protein in the lung and scarring of the lung.

Chronic silicosis may develop after exposure to lower levels of RCS long term and causes fibrotic nodules and shortness of breath. Chronic silicosis may include progressive massive fibrosis where the fibrotic nodules in the lung aggregate.

Additional diseases associated include; Chronic Bronchitis, Emphysema, Kidney damage, Lung cancer, Scleroderma

Who in particular is at risk?

Workplaces that manufacture, install or modify engineered stone have experienced a spate of instances of silicosis over the past few years, however it is expected that the number of cases recorded do not accurately reflect the number of instances occurring as it is not presently a reportable illness.

Additional workplaces that may provide an exposure include; building, construction and demolition work, preparing kitchen benchtops – stone, excavation, blasting, mining, brick manufacturing, road building, stonework, explosives, foundry.

Activities:

• brick cutting
• grinding masonry
• concrete cutting, chiseling
• cleaning up dust and debris from above mentioned
• cutting and working with manufactured stone

How can exposure be controlled?

As silica becomes respirable in dust form, it is important that exposure to dust is minimised to acceptable, safe levels. At the time of authoring Safe Work Australia’s Workplace Exposure Standard requires that respirable silica dust not exceed 0.1 mg/m³ as an eight hour time weighted average. To achieve this, it is recommended that dust extraction, wet cutting practices, isolation of the process area and the use of appropriate personal protective equipment such as respiratory equipment, be

implemented. Local exhaust ventilation and wet dust suppression practices have been shown to reduce dust by up to 99%.