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Asbestos Contaminated Land – Real Risk vs Perceived Risk

Updated: Jul 28, 2023

An unfortunate legacy of Britain’s industrial past is the significant presence of asbestos on most brownfield sites. The assessment and risk management of this type of contamination is a particular specialism which can often present challenges for construction professionals, developers and environmental consultancies (it has long been recognised that traditional site investigations do not always properly address asbestos-related risks in view of the particular hazards and risks which are specific to asbestos).


Correct interpretation of real risk (as opposed to ‘perceived’ risk) is essential to ensure safe site working practises; proper authorisations; safe and appropriate remediation plans; and legally accurate classification of waste materials can be achieved (note that incorrect waste classification can result in hugely inflated and unnecessary waste costs). In assessing this risk, the principal areas for consideration can be identified under four broad headings:


  1. Protection of the general public from risk associated with hazards on the land (Public Health consideration)

  2. Protection of personnel during any ground works (Health & Safety consideration)

  3. Treatment / disposal of contaminated waste products (Waste Management consideration)

  4. Contamination levels of developed site as a function of its end use (Occupier Liability and Environmental Management consideration)


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This requires consideration of, and compliance with, a range of Health & Safety, Asbestos, Environmental and Waste regulations, codes of practice and guidance, made all the more challenging as different ‘levels’ (or ‘thresholds’) of asbestos within the ground apply under the different regulatory regimes. Therefore, it is important to assess the options available for an asbestos contaminated site on its own merits whilst taking account of the range of applicable legislation, guidance and relevant ‘levels’. However, in all cases, the significance of the asbestos contamination would relate to the:

  1. Classification, condition and extent of ACM’s within the ground matrix, and the

  2. Concentration of ‘loose’ or ‘free’ fibres

Unfortunately, however, most industry standard Site Investigations and Geotechnical Assessments are relatively limited in respect of asbestos, with the asbestos consideration generally having been largely rolled in with the chemical testing suite, rather than an intrusive asbestos-specific ground investigation (or ground ‘survey’) having being carried out. This can result in bulk asbestos containing materials (ACM’s) being missed completely, no quantification of loose fibres being reported and a lack of interpretation on the real asbestos position and associated risk. Therefore, the real risk associated with asbestos may remain unknown even after an otherwise good quality SI and this makes it impossible to compare against relevant thresholds for considerations such as:

  • The risks to proposed end users of the site

  • The risk of fibre generation during works

  • The appropriate works classification, competency requirements, and notification status

  • Appropriate control measures during works to protect site workers and the general public

  • Remediation options (e.g. burial, re-use or retention of asbestos contaminated soils has certain restrictions depending upon risk profile)

  • Waste classification of materials (which depends critically on bulk ‘fragment’ content and loose fibre concentration)

Therefore, it is strongly recommended that an asbestos-specific ground investigation be carried out by qualified and experienced asbestos surveyors/analysts specialising in asbestos contaminated land for any brownfield site, but particularly so on sites which already show a potential asbestos risk profile – i.e. where there is:

  • Asbestos debris identified on the ground surface

  • Evidence of asbestos findings in an SI (irrespective of how ‘insignificant’)

  • Presence of ‘made ground’ across the site (which often contains ACM’s from a legacy pre-dating modern asbestos controls) irrespective of whether an SI mentions asbestos

  • Suggestion that historic structures may have collapsed or been demolished on the site (causing possible ground contamination with ACM’s) or infilling/backfilling

  • Suggestion of fly-tipping

It is understood that ‘additional’ investigations of this nature may be considered by some as an unnecessary expense but it is worthy of note that the proper assessment of risk simply cannot be carried out without the appropriate data. Also, the consideration of options which may have the potential to save considerable sums of money (such as waste classifying, re-using material, retention of contaminated material on site, etc.) all rely on the asbestos risk being properly categorised and based on an accurate asbestos contamination profile. ACS’ expertise in this arena started in the 1980’s with early research into correlations between soil asbestos levels and resultant airborne fibre concentrations (research which still has relevance in modern standards) and we have amassed over 30 years of experience to date, assessing and project managing a number of the largest asbestos contaminated land projects in Europe. This has resulted in the development of a team who can provide strategic, technical and operational management of a brownfield regeneration project from initial assessment and appraisal of viable options through to site completion and classification/treatment/disposal of waste. Over the past year we have achieved single site cost savings of up to £4m through detailed site assessment and the application of remediation plans based on real risk.

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