Characteristics
Asbestos is a naturally occurring, fibrous group of minerals including:
- chrysotile ('white asbestos')
- amosite ('brown asbestos')
- crocidolite ('blue asbestos')
- actinolite
- tremolite
- anthophyllite
Asbestos fibres have extraordinary tensile strength, conduct heat poorly and are relatively resistant to chemical attack.
Hazardous properties
Asbestos is a Group 1 carcinogen, meaning there is 'sufficient evidence of carcinogenicity in humans' (International Agency for Research on Cancer, 2012). Inhalation of fibres is associated with an increased chance of incurable lung cancer and mesothelioma, a cancer that develops in the lining covering the body's internal organs. Age of first exposure influences the chances of mesothelioma.
Asbestosis is a disease associated with high exposures, such as those in historic workplaces.
Pathway
Some asbestos products contained fibres while others encapsulated the fibres in a matrix. For exposure, fibres in the soil need to be released into the air and then inhaled.
Occurrence
Asbestos was used extensively in buildings and many industrial facilities. Imports of asbestos to the UK for use in construction and as a fire-retardant material ceased in 1999 due to its known health issues. It remains widespread in many buildings and as a soil contaminant. Where decommissioning or demolition are carried out without first removing the asbestos, fibres and fragments of asbestos-containing materials (ACMs) can be spread and mixed into soil. Waste disposal of ACMs can also result in soil contamination or caches of asbestos waste. Not all fibres are asbestos; manufactured fibres, as well as organic fibres, may look like asbestos fibres. Definitive identification can only be made using a microscope
Natural occurrences
Not relevant for Gateshead.
Site investigation
Desk study
Past land uses could have involved the use of asbestos materials. The key is the extent and care with which any asbestos removal was carried out prior to demolition. Careful material handling is needed to both comply with the law and to minimise the volume of waste containing asbestos.
Walkover
Made ground and demolition rubble are key areas to look out for in a walkover. Asbestos cannot be definitively identified with the naked eye. Asbestos was contained in a wide range of products including:
- cement-bonded sheets, slates and pipes
- insulating boards and tiles
- insulation and lagging
- sprayed coatings
- asbestos textiles (rope, yarn and cloth)
- millboard
- paper and paper products
- bitumen felts and coated metal
- flooring materials (i.e. tiles)
- textured wall coatings and paints
- reinforced plastics, mastics, sealants, putties and adhesives
- brake discs and gaskets
Intrusive site investigation
Site investigations are likely to be non-licenced work (NLW) under the Control of Asbestos Regulations 2012. Compare AGS Guidance and CIRIA C733.
Foundations
Excavations may disturb ACMs and potentially release or generate fibres. Supervisors should be trained in appropriate response (e.g. CIRIA C765).
Remediation
Pathway interruption
- Capping.
- Hand picking where ACM contamination is minimal and comprises fragments visible with the naked eye.
Source removal
- Excavation and off-site disposal.
- Hand picking of ACM fragments.
Waste disposal
Waste containing asbestos needs special precautions under transport of dangerous goods legislation. Excavated soil or made ground is likely to be hazardous waste and disposal options will be limited. There are two landfill sites in Gateshead permitted by the Environment Agency to accept asbestos.
Regulatory aspects
The Control of Asbestos Regulations (2012) and associated Approved Code of Practice (ACOP) seek to minimise the spread of and exposure to asbestos. Work with asbestos may be licenced work (LW) or non-licenced. Non-licenced work may need to be notified to the Health and Safety Executive (NNLW) or can be carried out without such notification. Employees need to be given relevant instruction, information and training. Workers on asbestos site should have asbestos in soil awareness training. Further training is needed if the work on asbestos is deemed to be NLW or LW.
Acronyms
| Acronym | Meaning |
|---|---|
| ACM | Asbestos-containing material |
| AC | Asbestos cement |
| AIB | Asbestos insulating board |
| HSE | Health and Safety Executive |
| LW | Licenced work |
| NLW | Non-licenced work |
| NNLW | Notifiable non-licenced work |
References
CIRIA C765. 2017. Asbestos in soil and made ground good practice site guide.
CIRIA SP168. 2014. Asbestos in soil and made ground: a guide to understanding and managing risks.
Control of Asbestos Regulations. 2012. Managing and working with asbestos. L143: Approved Code of Practice.
International Agency for Research on Cancer. 2012. Arsenic, Metals, Fibres, and Dusts. IARC Monographs on the Evaluation of Carcinogenic Risks to Humans, Vol. 100C. (Lyon, France: World Health Organisation).
Nathanail, P, Jones, A, Robertson, A, and Ogden, R. 2014. Asbestos in soil and made ground: a guide to understanding and managing risks. CIRIA Report C733. (London: CIRIA.)
Document contact
Dr Darren Beriro: darrenb@bgs.ac.uk