Engineered Stone Ban: The Ongoing Importance of Silica Monitoring
Engineered Stone Banned Nationwide From 1 July 2024
The construction and manufacturing industries are undergoing significant changes in response to mounting evidence of health risks associated with respirable crystalline silica (RCS). The upcoming ban on engineered stone in Australia highlights a growing awareness and regulatory response to the dangers posed by RCS.
The ban aims to prevent exposure to silica dust from engineered stone which has been linked to an unprecedented increase the number of workers who have developed silicosis across Australia in recent years. Silicosis has proven to be a deadly disease, causing irreversible lung scarring which can lead to chronic respiratory symptoms such as shortness of breath, coughing and chest pain. According to Cancer Council Australia, silicosis has also been linked to lung cancer. A study by Curtin University in 2022 estimated that approximately 10,000 Australians will develop lung cancer, and over 80,000 will be afflicted by silicosis as a result of current exposure to RCS.
Engineered stone is particularly hazardous to work with due to its extremely high silica content compared to natural stone which, when cut, blasted or grinded, creates RCS dust particles. By prohibiting the manufacture, supply, processing and installation of engineered stone, Safe Work Australia expects to see a significant reduction in cases of silicosis within Australia.
Other Sources of Respirable Crystalline Silica
Despite the ban on engineered stone, RCS can also be found in many other sources commonly found in a range of industries including construction and mining (see table below). As a result, monitoring respirable dust is still an essential element in ensuring workers are not exposed to excessive levels of RCS from other sources.
Whilst silica is not present in these sources in as high concentrations as in engineered stone, workers may still be exposed to hazardous amounts during drilling, excavating, tunnelling, digging, grinding, sawing, cutting, crushing, or polishing these materials.
The Ongoing Role of Monitoring in Silica Protection
Due to the ongoing importance of protecting workers from RCS and other types of respirable dust, monitoring in workplaces remains essential to ensure compliance and most importantly, to protect the health of workers. The exposure standard for RCS under the model workplace exposure standards is 0.05 mg/m3 time weighted average (TWA). PCBUs must not allow workers to be exposed to levels of RCS in excess of this limit. Air sampling and real-time dust monitoring are two essential components of a comprehensive dust monitoring program.
Air Sampling for Respirable Crystalline Silica
Air sampling is the foundation of any air monitoring program including those targeting silica. The Workplace Health and Safety Regulations require PCBUs to conduct air monitoring to determine the concentration of silica dust in the worker’s breathing zone, whether there is a risk to a worker’s health, and if there is any uncertainty as to whether silica dust levels exceed the exposure standard.
Monitor and inform workers of their exposure patterns
Determine what level of respiratory protective equipment is necessary
Inform any other health monitoring requirements
Air sampling should be used to obtain a baseline level of silica dust which can then be compared to further sampling results taken at least every twelve months, when work practices change, or in other circumstances that require updated air quality data.
Sampling must be conducted in the breathing zone (within a 30cm radius of the worker’s nose or mouth) so that results are representative of actual exposure. This requirement is met with a sample train set up where the sample medium is attached to the worker’s clothes within their breathing zone which is then connected by a tube to a personal air sampling pump. The air sampling pump, such as the SKC AirChek Connect Personal Air Sampling Pump, must be capable of maintaining a 3L/min flow rate for the entire sampling duration (e.g. shift length). After the sampling period is complete, the sampling medium is sent to a laboratory for gravimetric analysis where the specific airborne contaminants and their respective concentrations can be determined.
This process provides detailed data that can be used to show compliance. However, results are not available until after laboratory analysis, meaning that any unexpected cases of high exposure may not be identified until results arrive. The delay in results also makes it difficult to diagnose what actions or circumstances produced the result, especially if a long period has passed. While periodic gravimetric sampling is required to comply with regulation, safety can be further enhanced through supplementary monitoring to help compensate its limitations.
Real-Time Dust Monitoring for Respirable Dust
Real-time personal dust monitors generally do not directly monitor the concentration of silica. Instead, real-time personal respirable dust monitors such as the DustCanary Trend 420 measure the mass concentration of respirable dust (smaller than 10µm) in the air. This data can be used in conjunction with gravimetric analysis to grant insights into respirable dust concentration on a day-to-day basis. With continuous measurements of real-time concentrations, occupational hygienists and safety professionals gain the advantage of being able to determine what tasks, areas or behaviours resulted in greater levels of exposure to respirable dust by comparing peaks in readings to a worker’s activities throughout the day. Software such as NIOSH’s EVADE is also available to synchronise recorded dust levels with video footage so that users can pinpoint the exact circumstances where exposure peaked. This allows site managers to better understand their site’s hazards and respond accordingly with targeted countermeasures.
Real-time dust monitors are also equipped with audiovisual alarms that can be configured to trigger instant warnings when set exposure thresholds are exceeded. These alerts allow workers to quickly leave hazardous areas, halt any activities generating excessive levels of dust, and take action to reduce dust concentrations to safe levels, minimising exposure and reducing incidences of respiratory illnesses and other dust-related health issues.
A wide range of real-time dust monitoring instruments as well as air sampling pumps and consumables are available Air-Met Scientific for sale, rental and service. To learn more, contact your local team today.
