Q: My development site has asbestos in soil – how do I know what the risks are and how do I manage them?

Asbestos may be present in soil as discrete fibres, or as pieces of building material; for example fragments of asbestos cement roof tiles or thermal insulation debris.

If asbestos is present in soil on your development site, there are three key questions you need to ask:

• Can I leave the asbestos on site and, if not, how do I dispose of it?
• How do I protect end users of the site once the development has been completed?
• How do I protect workers and the general public as the earthworks and construction are in progress?

Protection of future site users

To determine whether asbestos in soils could be a potential risk to end users, the first step is to carry out a risk assessment. The risk assessment would generally be carried out by an environmental consultant as part of a ground investigation, where asbestos would be considered along with a range of other chemical contaminants. The risk assessment should follow guidance set out in Environment Agency document Model Procedures for the Management of Land Contamination (CLR 11), and Asbestos in soil and made ground: a guide to understanding and managing risks (CIRIA C733).

The presence of asbestos does not necessarily mean that contaminated soil needs to be removed from site. In many cases, the risk assessment may demonstrate that the soil is safe to remain in situ, with or without a simple clean cover system over the contaminated soil. However, if unacceptable risks are identified, then remediation of the site is likely to be necessary. 

Asbestos in soils will only present a risk if there is potential for asbestos fibres to be released from the soil and subsequently inhaled by site users. When this is the case, remedial measures are needed. Often, the simplest form is to break this exposure pathway by placing hardstanding (or a building) above the contaminated soil.  Where soft landscaping is planned, a cover system such as clean soil and a geotextile marker layer can be designed to provide a suitable barrier.  Other possible types of remediation include picking or screening of asbestos from soils, and solidification/stabilisation of soils to prevent fibre release. Provided that relevant legislation is followed, asbestos-contaminated soils can potentially be reused in other areas of a site, for example by preparing and following a Materials Management Plan.

If these risks and options are identified in an early assessment, allowing designers to take into account which areas of the site have a higher risk, it is likely there will be minimal cost impacts on a project. For example, identifying a high risk area can ensure that the space is used for low impact purposes where less remediation is required, such as a car park.

Protection of workers and the general public

During earthworks, the nature of risks from asbestos in soils to site operatives and the general public is different to that posed to the site end users. The risks of exposure are greater due to the soil being excavated, exposed, stockpiled and transported around the site, which requires the consideration of different risks and control measures.

The 2016 ‘CAR-SOIL’ document, produced by CL:AIRE and the Asbestos in Soil and C&D Materials Joint Industry Working Group, provides industry guidance on applying the Control of Asbestos Regulations 2012 to projects involving asbestos in soil.  The regulations require employers to carry out risk assessments where work with asbestos is necessary, to reduce exposure to asbestos and to prevent the spread of asbestos.

To stay compliant with the regulations, an Asbestos Management Plan is often prepared by an environmental consultant who is experienced with working with asbestos in soil. The Asbestos Management Plan will be site-specific and the control measures will vary depending on the amount and type of asbestos present, the sensitivity of the site and the type of work to be carried out.   Depending on the complexity of the project, the Asbestos Management Plan may cover the entire site, or different controls may apply to different zones or stages of work.  An Asbestos Management Plan would generally consider the following:

• A risk assessment specific to the project – what is the nature of the asbestos, what are the exposure pathways, and who is potentially at risk?
• Is the work classed as licensed work or non-licensed work?
• Does the Health & Safety Executive need to be notified of the work?
• What are the personal protective equipment (PPE) and respiratory protective equipment (RPE) requirements?
• What type of training do operatives require?
• What control measures need to be considered during earthworks? This may include damping down, material handling, stockpiling, soil sentencing, etc.
• Decontamination of operatives and site plant.
• What are the waste disposal options?
• Does the site require reassurance air monitoring? This may take place close to the work activities, or at the site boundary to ensure that neighbours aren’t impacted.

In summary, while the mention of asbestos will ring alarm bells for many developers and contractors, the presence of asbestos in soil should not provide a barrier to cost-effective development - provided that a suitably qualified environmental consultant is introduced to the project as early as possible. By adapting the project design and incorporating short and long term risk mitigation measures, this will ensure that risks are appropriately controlled and managed. SOCOTEC has teams of consultants across the UK that can get involved and steer you through the process.

Follow the link for detailed information for contractors on what to do when excavating asbestos in the ground.