When asbestos is found in soil, it is usually because 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 or 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 because 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.
The asbestos contaminated soils: Information sheet provides advice to persons in control of a workplace and those involved in inspecting, removing, managing or disposing of asbestos contaminated soils at workplaces.
A Class A licence holder is required for situations where the soil is contaminated with friable asbestos or a mixture of friable and non-friable asbestos. For contamination of soil with a total quantity of more than 10 square metres of non-friable asbestos, a Class A or Class B licence holder can be used. For minor contamination of 10 square metres or less of non-friable asbestos, a competent person may be used.