Respirable Crystalline Silica

In March 2016 the CMPA published a Dust Management Guideline after extensive consultation with Members and Government including the EPA. The abbreviated table of contents is listed below.

Below are some extracts from the Guideline.

Respirable Crystalline Silica (RCS) is found in sand, stone, concrete and mortar. It is also used to make a variety of products including composite stone used to fabricate kitchen and bathroom benchtops, bricks, tiles and some plastics. When workers cut, crush, drill, polish, saw or grind products that contain RCS, dust particles are generated that are small enough to lodge deep in the lungs and cause illness or disease including silicosis.

Safe Work Australia (SWA) set exposure standards for hazardous substances which are then adopted by the state or territory WHS regulatory authorities such as WorkSafe Victoria.

Action Levels

An action level triggers actions to control exposure ensuring all employee exposures stay well below the exposure standard. Industry best practice is to adopt an action level that is half of the SWA exposure standard, i.e. 0.05mg/m3 for RCS Dust (RCSD).

The Australian Institute of Occupational Hygienists (AIOH) recommends trigger values for these other dusts. Trigger values serve the same purpose of action levels and AIOH recommend they should be adopted by industry.

Exposure standards are based on a 40 hour week.

To ensure the exposure standards and action levels are representative of the time worked, a formula called Time Weighted Average is used (TWA):

TWA is the average airborne concentration of a particular substance when calculated over a normal eight hour work day, for a five day working week, i.e. 40 hour week.

Following are developments since the publication of the CMPA Dust Management Guideline (March 2016):

1.June 2017 Change in USA TWA for RCS, Occupational Safety and Health Administration: applies to all occupational exposures to RCS in construction work, except where employee exposure will remain below 0.025 mg/m3 as an 8-hour TWA under any foreseeable conditions. Respirable Crystalline Silica establishes an 8-hour TWA Permissible Exposure Limit (PEL) of 0.05 mg/m3 and an Action Level of 0.025 mg/m3.

2.September 2018 European Union: According to the European Commission, even though some companies have good control of airborne concentrations of it, RCS generated by a work process such as cutting, mining, crushing or grinding of silica-containing materials remains a leading cause of both the lung disease ‘silicosis’ and occupational lung cancer. Therefore, it proposed a new OEL for this chemical with a limit of 0.1 mg/m3. However, the 0.1 limit is considered not to be enough to ensure proper protection. For example, in British Columbia the limit is set at 0.025 mg/m3. In Ireland, Italy, Finland, Portugal and the United States the limit is set at 0.05 mg/m3. The European Commission also committed itself to evaluate the need to modify this limit by the first quarter of 2019 at the latest. Therefore, a stricter limit for respirable crystalline silica dust in the EU may be proposed.

3.October 2018 ABC 7:30 Report: In the past three financial years in Victoria there have been 16 silicosis claims by stonemasons. October 2018 Decrease in TWA for RCS: Victorian Trades Hall Council: Advocating for trigger level of 0.025 mg/m3 in October 2018.

4.October 2018 National Registry: The Victorian government will push for the urgent establishment of a national registry and review of the current standards to reduce the risk of stonemasons contracting silicosis.

5.November 2018 WorkSafe RCS in the Extractives Industry Meeting: A meeting was convened by WorkSafe consisting of industry and union representatives. The purpose of the meeting was to discuss the Victorian Trade Halls Council push for lowering the TWA for RCS to those set by the USA Occupational Safety and Health Administration. An action item was for WorkSafe to draft extractives specific guidance taking a similar approach to the WorkSafe guidance material “Dust containing crystalline silica in construction work”.

6.December 2018 Workplace Exposure Standards review Safe Work Australia: The aim of this review is to develop a list of health-based recommendations for Workplace Exposure Standards (WES) in Australia. Recommendations for changes will be based on an evaluation of available information from trusted domestic and international sources. Only publicly available information will be used. The review will result in recommendations for the workplace exposure standard values, notations and the list of chemicals. The recommendations and supporting information will be published in individual evaluation reports for each chemical including respirable crystalline silica and should be complete by December 2019.

In summary, there has been a focus in the Australian media on RCS due to a rise in silicosis (mostly affecting stonemasons). With the review being conducted by Safe Work Australia on Workplace Exposure Standards there may be a change in TWA to a lower exposure limit.

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