When asbestos is found in soil, it is usually as a result of:

• inadequate asbestos removal work or demolition
• degradation of a building or structure on site
• legacy or recent illegal dumping
• waste burial
• past use of contaminated fill/top soil.

Asbestos in soil poses a risk to the health of workers if the fibres become airborne and are then inhaled. The likelihood of exposure depends on the:

• quantity and distribution
• condition – whether it is non-friable (bonded) or friable (crumbles under hand pressure, non-bonded)
• level of disturbance
• systems of work and controls used to limit the release and inhalation of asbestos fibres.

Non-friable asbestos is asbestos that is bound tightly in a matrix (e.g. asbestos cement fencing, eaves). Non-friable asbestos may become friable after severe degradation, such as during a fire or as a result of a chemical ‘attack’.

Friable asbestos refers to asbestos that can be broken up using hand pressure. Examples include asbestos pipe lagging, asbestos fibres spread by high pressure cleaning of asbestos cement or fire damaged asbestos cement sheeting that has fragmented.

Friable asbestos presents a greater health risk than non-friable due to the increased chance of fibre release.

Asbestos contaminated soils must be inspected by a competent person, such as a consultant, who has acquired through training, qualification or experience, the relevant knowledge to carry out the task. The level of detail required for an inspection depends on a number of factors, including:

• background knowledge of the site
• the likely amount and type of asbestos contamination (including sampling and analysis where necessary)
• the likely source of the asbestos contamination.

Residential sites with contamination can be reported to the local government authorised officer (environmental health officer) who has powers to regulate asbestos contamination under the Health (Asbestos) Regulations 1992.

For extensive or legacy asbestos contamination, the site should be reported under section 11 of the Contaminated Sites Act 2003. For more information on reporting and assessment of contaminated sites, refer to the Department of Health’s Guidelines for the Assessment, Remediation and Management of Asbestos Contaminated Sites in Western Australia.

Under the Work Health and Safety (General) Regulations 2022, recent or minor, small scale workplace soil contamination can be removed using safe systems of work.

Removal of non-friable asbestos in soil contamination of 10 square metres or more (total asbestos surface area) may be conducted by a Class A or Class B asbestos licence holder. If the asbestos contamination is friable or mixed friable/non-friable, a Class A asbestos licence holder must be engaged. An independent consultant may also be required to assess and manage the site to address the client’s compliance with environmental legislation.

Table 1 Asbestos removal licensing requirements

It is important to note that soil remediation work is a specialised activity and may require additional competency, skills and resources. The selection of a Class A or Class B licence holder should consider the resources, skills and experience required for soil remediation work. Controls and safe systems of work in accordance with work health and safety legislation must be used during the removal of asbestos in soils.

Controls for removal work that is not small-scale or minor should include, but not be limited to:

• appropriate planning (e.g. preparation of an asbestos management plan/safe work method statement for the site)
• selecting mobile plant with cabin air filters where practicable
• restricting access to the work site
• isolating and securing the removal work area using signs and barriers
• implementing systems to control cross contamination of ACM between vehicles and uncontaminated areas of the site, including buildings
• controlling dust with dust suppression techniques (e.g. water and wetting agents)
• providing information and training for workers on hazards and safe work practices to minimise exposure
• selecting and providing the correct personal protective equipment and respiratory protective equipment
• implementing decontamination procedures for workers and equipment.

Following asbestos removal, the adequacy of the work will need to be assessed and a clearance conducted. The clearance must be conducted by an independent competent person (ICP) who has knowledge, training and experience in asbestos removal and holds certification for asbestos assessor work or a relevant tertiary qualification.

For soils contaminated with friable asbestos, the ICP must be a licenced asbestos assessor (LAA). Independent means the ICP or LAA must not be involved in the removal of asbestos for that specific job or be involved with the asbestos licence holder removing the asbestos for that specific job.

The soil validation will depend on the remediation approach adopted and the form of asbestos. Sampling should be conducted to check that the decontamination is complete. Air monitoring should be conducted based on risk to ensure exposure controls are effective.

For more information on soil validations, refer to the Department of Health’s Guidelines for the Assessment, Remediation and Management of Asbestos-Contaminated Sites in Western Australia.

Asbestos is classified as a controlled waste, as listed in Schedule 1 of the Environmental Protection (Controlled Waste) Regulations 2004.

Prior to transport, all asbestos contaminated soils must be wet down and covered or contained to minimise the risk of dust and fibres becoming airborne during transport.

Moderate watering should be used such that the soil does not wash away or cause stability issues during transport. Contaminated asbestos soils must be contained and labelled in accordance with Schedule 9 clause 8 of the WHS (General) Regulations 2022 before the waste is removed from site or prior to transport to a licensed waste facility.

Appropriate systems of work must be applied to decontaminating vehicles used to transport asbestos contaminated soils.

Where appropriate, ACM contamination may be contained on site in compliance with the Contaminated Sites Act 2003, associated regulations and guidelines administered by the Department of Water and Environmental Regulation. In such situations, the site would be classified under section 13 of the Act and a memorial placed on the title.

Containment of asbestos on site does not relate to asbestos that is part of a building or structure, or to fly tipped/dumped asbestos, and this must be removed in accordance with work health and safety legislation.

In certain circumstances, the site may be registered on a public access database and subject to mandatory disclosure requirements at sale or lease. A site management plan (SMP) may be required to describe appropriate measures for managing the disturbance of contaminated soil and to protect future site workers and users.

An SMP should include:

• information on the location of ACM contamination, including coordinates and depth
• inspection and maintenance of a barrier above the contaminated soil
• notification of workers in the area prior to work commencing, so that a safe system of work can be implemented
• established safe work practices for identifying and repairing any damage to the barrier.