Fires involving asbestos containing materials (ACM) can produce asbestos debris, including unburnt and partly burnt pieces. Some ACM can be severely damaged by fire. All ACM that is affected by fire should be treated as friable.
During a fire, ACM will typically crack or spall. Asbestos fibres released during a fire are mainly released through spalling. Spalling occurs when the heat of the fire turns water inside the ACM to steam, creating a build-up of pressure which results in flakes of the material forcefully popping off.
Although fires can produce asbestos debris, air monitoring conducted during and after fires generally shows a very low concentration of asbestos fibres. This is likely due to the low numbers of fibres actually released and the large volumes of air circulated by fires.
Minor disturbances, such as walking on the site or wind blowing over the site, are unlikely to generate significant quantities of airborne asbestos. More significant disturbances, such as during clean-up or demolition of the fire-damaged building, must be done safely to ensure the level of asbestos fibres in the air is kept very low.
The following precautions should be implemented to minimise the risk of exposure to asbestos fibres following a fire: