Multidisciplinary Engineering Consultants

When is a perceived Asbestos hazard not a hazard?

There is often a knee-jerk, fearful, reaction to the discovery of Asbestos-Containing-Materials (ACM) in soils on a site. However asbestos impacted soils are little different to any other contaminated soils; the risks are assessed and measures are derived so that ideally the contaminated soils remain on site i.e. ensuring that significant Asbestos risks are removed by the time construction is completed.

The greatest risk to humans is not usually to the end-users of a site (e.g. residents), but to the construction workers disturbing and handling impacted soils. In both cases, risks can usually be reduced to acceptable levels.

In terms of construction workers, there are legal regulations that cover working with asbestos-impacted-soils.  In 2016 the contaminated land industry issued guidance that presented a definitive explanation of the legal requirements of the Control of Asbestos Regulations (CAR) 2012 in relation to working with Asbestos-contaminated soil, as well as Construction & Demolition materials. Under CAR 2012, only workers who are suitably Asbestos-trained are permitted to disturb, or handle Asbestos and that includes in soil. The minimum training is “Asbestos Awareness”. In all situations, increased risk requires an increase in the degree of training and may require the work to be licensed. All of this aims to ensure workers are safe. Assessing risks to end-users of a site is dealt with in numerous other contamination industry publications.

The first thing before investigating the ground at any site is to undertake some research to establish where Asbestos risks may lie in structures on site, to what degree and in what form the ACM is. However, our experience is that even if it exists in the structures, if no Asbestos has been found in the ground, it can still be present, as there are some areas on brownfield sites where Asbestos waste is often found; dumped, hidden, even used to assist construction and it may not get found by demolition contractors. In terms of disposal off-site, this means that demolition materials that are routinely ‘Inert’ waste, jump to ‘hazardous’ with no feasible means of avoiding it…..but you can be forewarned. Asbestos can also be present where ACM has degraded to loose fibres, with such fibres invisible to the naked eye.

Once you’ve identified the impacted materials/soils, then retaining these materials on site beneficially avoids the high costs of their disposal# to a licensed waste disposal site, potentially as hazardous waste. These additional costs could kill some projects such as community/charity ones. Many do not appreciate that there are different classification systems for risks to humans compared to off-site disposal.  A soil that is hazardous waste does not necessarily mean it is a hazard to humans or, if it is, then the hazard can usually be reduced to acceptable levels by careful engineering design.

Engineered measures to reduce the risks require careful thought, as some ill-conceived measures can lead to the relocation of impacted soil on a site being classed as “waste disposal”, thus either requiring it to have an Environmental Permit (formerly Landfill License), or, in the worst case scenario, to be removed from a completed site.

One last warning!  Beware of demolition crush stockpiles on sites and of importing recycled demolition crush, as these can run the risk of containing ACM, made worse if the material has been crushed and loose fibres released. You can never guarantee all ACM to have been removed from structures and it is quite legal to leave some low-risk ACMs in structures being demolished, but then the resulting rubble cannot be reused as a “recycled aggregate”. Furthermore, Asbestos Surveys often miss hidden and ‘inaccessible’ ACM and so it ends up in demolition rubble.

If you would like assistance with ground assessment and particularly Asbestos in soils, André Gilleard, one of our specialists on the Register of Qualified Persons for the CL:AIRE Definition of Waste: Development Industry Code of Practice (DoWCoP), and a Specialist in Land Condition (SiLC) would be pleased to help. 0117 929 2244.

(#: visible fragments of ACM in soils for off-site disposal, will invariably cause the soil to be classed as 'hazardous', but it depends on the ACM type. ACM itself is almost always ‘hazardous’ waste. Classification of soils containing only loose Asbestos fibres, depends on the % of asbestos and such can be under- or over-estimated by inappropriate sampling).