Asbestos is a category 1 carcinogen. Disturbance of asbestos containing materials (ACMs) can place anyone in the vicinity at risk of asbestos related diseases such as asbestosis, lung cancer or mesothelioma, if asbestos fibres are inhaled.
Asbestos is a set of six naturally occurring silicate minerals used commercially for their desirable physical properties. In 1985, the UK banned the use and import of materials containing amosite (brown) and crocidolite (blue) asbestos, followed by anthophylite, tremolite and actinolite in 1992 and chrysotile (white) asbestos in 1999. The European Union banned all use of asbestos, as well as the extraction, manufacture, and processing of asbestos products in 2005.
Approximately 60% of asbestos used in the UK was in construction materials. If a building was developed prior to 2000 there is a possibility that asbestos could be found within its construction and the surrounding soil, especially if redevelopment has occurred on the site.
Asbestos in soil is a health hazard if asbestos fibres become air-borne and inhaled. The risk is dependent on the quantity and type of asbestos contaminated material. Encapsulated and bonded asbestos products such as vinyl tiles, adhesives, bitumens, reinforced plastics, textured coatings (Artex) and cement products have the lowest risk of fibre release because the asbestos fibres are bound within the matrix and it requires destructive force to liberate the fibres into the air. The highest risk is from friable loose fibres encountered within the soil that can be easily liberated when disturbed.
The presence of asbestos contamination in the ground can be identified by visual observation (large fragments) and laboratory screening and analysis (small fragments and loose fibres). The person responsible for the management of the site must ensure any visible asbestos containing material is removed or controlled.
Any site investigation should consider carefully the potential for asbestos to be present, and screening for asbestos should be included within the remit for any site investigation.
A competent person should inspect the soil, carry out testing and prepare a risk assessment to assess the impact from asbestos. All RSA Geotechnics site and laboratory personnel are trained in the identification and handling of asbestos containing materials.
Remedial measures typically comprise the removal of asbestos for disposal off-site, however in some circumstances it may be preferable to contain the asbestos on site if it can be demonstrated that there will be no adverse impact to site receptors (e.g. encapsulation beneath a building).
There are strict controls on the handling and disposal of asbestos.