NSW chief scientist releases report on management of asbestos

The NSW chief scientist Dr Hugh Durrant-Whyte has released his final report on the management of asbestos. Titled Management of Asbestos in Recovered Fines and Recovered Materials for Beneficial Reuse in NSW, it came out in December 2024.

Among the findings from the chief scientist were:

Thresholds

Varying definitions for asbestos, asbestos material and asbestos waste in different legislation result in a level of confusion when managing asbestos.
In respect to environmental management, only a few national and international jurisdictions have established asbestos thresholds (or limits) in waste for recycling. Thresholds have been used a part of a broader risk-based approach to managing asbestos in waste.
The context of any threshold needs to be clearly understood. Where thresholds have been established by environmental agencies, they are based on the NEPM’s HSL values, the limit of detection for a specified method of analysis or based on experimental estimates of potential respirable fibre count.
Studies that correlate concentration of asbestos in waste to asbestos-related disease levels were not identified in any literature.
Health-related evidence to support thresholds is generally based on predicted disease risk rather than a link between asbestos concentration and asbestos-related disease.
Within Australia, thresholds (or limits) are utilised within WHS requirements, although these cannot be interpreted as an acceptable level of exposure, and more accurately reflect a maximum upper exposure limit.
The workplace exposure standard for airborne fibre concentration is 0.1 f/mL over an eight-hour period, five-day week.
WHS limits are supported by other requirements to manage risk and minimise exposure, noting different requirements are set for DIY home renovators in NSW.
In general, risk is considered based on a correlation between asbestos concentration in material and concentration of respirable fibres measured in air (similar to Swartjes and Tromp (2008)).
Experimental estimates of fibre release from soil found that ‘activities involving soil with friable asbestos concentrations of 100mg/kg of soil were unlikely to result in airborne fibre levels above ‘Negligible Risk’ level of 1000 fibre equivalents/m3 (0.001 f/mL).’
Asbestos soil concentrations below 0.01% are unlikely to generate airborne fibres above 0.01 f/mL
Additional safety factors may need to be considered when establishing thresholds for waste and recovered materials.

Sampling and Analysis

There are a limited number of guides for sampling and analysis of asbestos in waste (i.e. recycled end product). Soil sampling guides are widely understood and available for asbestos sampling and analysis.
It is challenging to obtain a representative sample for analysis with high confidence due to the heterogeneity of the materials and non-uniform distribution of asbestos (i.e. hotspots).
Visual identification of ACMs remains the first key step in detecting asbestos, whether at the demolition site, the receiving/tipping point at recycling facilities, or during analysis procedures in the field or laboratory.
Current methods using NEPM gravimetric and AS 4964 (now superseded by AS 5370) laboratory analysis are sufficient to detect and estimate asbestos content in recovered materials; however, their limitations and applications to end product must be understood.
Appropriate training and internal/external quality assurance through accreditation of those undertaking asbestos sampling and analysis are critical to ensure the competency of the analysts and minimise variability in reporting results.
Sampling in WA Waste Guideline focuses on assessment of the end product by targeting areas with visible suspect asbestos materials. The samples are analysed using gravimetric method and AS 4964 to estimate the total asbestos content.
Interpretation of sampling and analysis results in WA Waste Guideline applies a multiple-linesof-evidence approach to deciding whether the stockpile meets the product specification of 0.001 per cent w/w asbestos.
In the case of exceedances in a stockpile, investigation of the cause must be carried out and preventative measures must be taken to prevent a future occurrence. Any actions taken on the stockpile must be recorded.
A generic sampling and analysis plan for asbestos in recovered fines and materials is unlikely to provide a high level of confidence. The sampling and analysis of end products need to consider the sampling objectives, sampling strategies in the field, the limitations and applicability of selected analysis method and data quality assessment.

Risk-Based Approach

The current approach to managing asbestos in C&D waste in NSW does reflect a partial risk-based approach at specific stages, but it does not follow through the chain to the end use of recycled materials.
The current controls in asbestos management in NSW include a requirement for safe handling and disposal of asbestos, tracking of asbestos waste, visual inspection of incoming waste and end-use control of recycled products.
Lack of knowledge/awareness of asbestos presence, lack of practical skills to identify and handle ACMs, avoidance of disposal costs, and inadequate surveillance activities contribute to risks in asbestos management.
There is general support for a through-chain risk-based approach focusing on source separation for effective asbestos management, although reservations on the approach’s implementation and practicality remain.
Early intervention through asbestos identification and removal at the source can more effectively prevent asbestos contamination downstream, where it becomes dispersed and harder to detect and remove.
The mapping of asbestos management in the recycled waste value chain suggests that having multiple barriers through the chain can minimise the risk of asbestos contamination and exposure; this can be done by implementing a combination of process controls and supporting programs and policies at every stage.
Conceptual design and elements of the through-chain risk-based approach for asbestos management in C&D waste can be drawn from case studies from other states in Australia and overseas.
The WA Waste Guideline has a comprehensive risk-based approach to managing asbestos in waste for re-use that incorporates pre-acceptance procedures, a material risk classification matrix during acceptance procedures, waste processing controls, and sampling and analysis of the end products to validate the effectiveness of quality assurance and quality control processes.

Recommendations:

Recommendations from the chief scientists office included:

Recommendation 1) The NSW Government implement a coordinated, through-chain risk-based approach to managing asbestos in recovered materials, incorporating a suite of specific recommendations on the application of thresholds, sampling and analysis designed to ensure that potential risks are understood and mitigated at each step in the value chain. Individual recommendations should not be considered in isolation.

Recommendation 2: NSW Government considers implementing a threshold for asbestos in recovered fines and materials for beneficial reuse. The threshold should:

Be based on the current criteria of 0.001 per cent w/w (asbestos in any form) as described in the Western Australia “Guideline: Managing asbestos at construction and demolition waste recycling facilities” and meet all the requirements that are: no no visible ACM; below 10 mg/kg weight of total asbestos/weight of product (i.e. 0.001 per cent w/w); and asbestos not detected using AS 5370.
Support a through-chain risk-based approach to managing asbestos in recovered fines and materials for beneficial reuse.
Apply to the end product, ready for reuse in non-contact scenarios, although the threshold could also be used as an in-process standard to verify the efficacy of processing steps.

Recommendation 3: NSW EPA develops material acceptance, inspection, sampling and analysis guidelines for asbestos in recovered materials to assess product quality against the set threshold in consultation with industry stakeholders. The sampling and analysis guidelines should:

Support a through-chain risk-based approach to managing asbestos in recovered fines and materials for beneficial reuse.
Consider the nature of different materials and processing chains.
Be validated by the results from a staged pilot program.

Recommendation 4: NSW EPA updates Standards for managing construction waste in NSW to include a through-chain riskbased approach by adopting WA Waste Guideline: Managing asbestos at construction and demolition waste recycling facilities.

Recommendation 5: NSW Government considers a staged pilot program of a through-chain risk-based approach to design, test and validate findings and recommendations from this report.

Recommendation 6: NSW Government engages with other jurisdictions to work towards a consistent approach and outcomes (including legislation) in managing asbestos in recovered fines and materials for beneficial reuse.

Recommendations 7: NSW Government considers stronger support for better source separation at demolition sites, including residential premises, through the identification of industry best practice with clear and consistent guidance, training and competency around robust asbestos identification and handling for all workers handling asbestos prior to disposal. The NSW Government evaluates the delivery of small grants funding for council-run programs to date to inform the design of a more systematic funding model. NSW Government improves and standardises data collection, collation and analysis procedures to better inform and adapt management as part of a through-chain approach.

Recommendations 8: NSW Government remains aware of emerging technologies that can assist with asbestos detection, and considers supporting the development and trialling of technologies that have high potential through a new NSW business research challenge program.

Recommendations 9: NSW Government facilitate development of national competency-based training for waste industry. NSW Government liaise with industry professional bodies to develop competency-based training for laboratory analysts, asbestos assessors/environmental auditors/occupational hygienists who consult or work with the waste industry.

For a comprehensive look at the 106-page report from the chief scientist, click here.