The management of asbestos in the workplace, during demolition, and its assessment and removal, are all highly regulated by the CAR Regulations (2006), plus a wealth of other Health & Safety Executive (HSE) guidance documents. However, there is currently no specific code of practice or recent guideline document for asbestos in soil, or for its management during a site investigation.

For several years, many site operatives/consultants/developers have considered asbestos in soil to be of major concern only if high quantities are present, leading to its definition as hazardous waste (> 0.1%).

Another common misapprehension is that asbestos is not such an issue as long as soil is generally wet, and no airborne fibres are likely to be generated.

However, over the last 12 months or so, current thinking on asbestos in soil has changed to a very different scenario, due to a number of initiatives by various industry bodies, some of which are described in this article.

Asbestos in soil is a risk: as soil dries and dust is formed, it can then be airborne. It also adheres to shoes and vehicles, and is therefore carried to other locations, and disperses as it dries. Considering the widespread use of asbestos in construction, the number of buildings demolished on sites for redevelopment, and the disturbance and movement of soil during site investigations, remediation, and redevelopment, there is obviously cause for concern regarding the risks.

But how much of a risk, and at what concentration? Currently, there is no Soil Guideline Value (SGV) for asbestos, so operatives within the industry usually work to >0.1% for hazardous waste definition, and >0.001% for human health risk assessment.

The 0.1% value is taken from a document produced by the Interdepartmental Committee for the Redevelopment of Contaminated Land (ICRCL), 1990, Guidance note 64/85 ‘Asbestos on Contaminated Sites’, (but this does not take into account the 2006 regulations) and the 0.001% value is based on research conducted at the Institute of Occupational Medicine (IOM), 1988, Addison et al ‘The release of dispersed asbestos fibres from soils’.

This latter study involved drying soil, and generating dust, which was passed through filters to trap asbestos fibres for subsequent measurement. A soil containing 0.001% of asbestos fibres generated concentrations in air of >100,000 fibres/m3 where the total dust concentration was < 5mg/m3.

Recent High Court rulings have awarded damages based on a limited increase in probability of exposure to asbestos. In one case, a 17% increased risk was sufficient. This has caused significant concern within many industries - consultants, contractors, developers, landowners, laboratories - all of whom must take great care to ensure their staff, and future site users, are protected in order to avoid potential claims if personnel develop an asbestos related disease in the future. Asbestos related claims cost the insurance industry more than any other category.