In a bid to deal with Britain’s need for more housing the government has been encouraging councils to bring forward building development on suitable brownfield sites. However, just walking onto the land can bring to light one particular problem that’s often just beneath the surface of the ground – asbestos waste.

The toxic legacy of Britain’s industrial past, which saw a total of 5.3 million tonnes of asbestos imported from the 1940s through to the end of the 1990s, can potentially still be found half-buried at the sites of former factories, foundries, mills and engineering workshops.

Asbestos-containing materials can be left behind

When old factory buildings are demolished, hazardous asbestos-containing materials can still be left behind and mixed in with the soil, rubble and debris. Lack of time, carelessness or inadequate asbestos awareness training could sometimes mean that demolition workers would not dispose of the asbestos material correctly or worse, asbestos contaminated soil was used as top soil or land fill.

Before any work can commence on a construction site, soil samples must be taken and analysed to determine if asbestos waste or contaminated soil is present, which could pose a potential health risk to all working at the site or to residents who live nearby.

In a recent case, “hazardous material” claimed to be asbestos was found on the site of a former Hartlepool factory site earmarked for housing redevelopment. Both the Environment Agency (EA) and the firm involved in clearing the site assert that there is no evidence to support the claim that the material is asbestos.

Thorough excavation and asbestos survey

According to the land clearance firm, the site had undergone a thorough excavation and asbestos survey two years earlier and all significant asbestos-containing products were removed to a licensed landfill facility. The firm are adamant that “No significant asbestos risk was considered to remain on completion of the works” further stating that documentation exists to show that asbestos was “disposed of properly” when the buildings were demolished.

However, it’s claimed that the waste material found appears identical to asbestos. As a grey-coloured material made originally from beige ‘white’ asbestos fibres, the waste is likely to be heavily discoloured and can often look indistinguishable from more recent types of asbestos-free materials found in the same condition. While blue and brown asbestos fibres were banned in the mid 1980s, white asbestos fibres were still being used to produce building materials, such as corrugated roofing and insulation board.

In response, the firm has agreed to carry out further investigations, including an asbestos survey, which involves digging up the land where it is said the asbestos has been found.

Significant health risk

There can still be a significant health risk to any person who comes into contact with asbestos contaminated soil, whether directly as a site contractor or indirectly as a member of the public due to the strong possibility of loose and disintegrating asbestos fibre particles becoming airborne.

The Hazardous Waste (England and Wales) Regulations 2005 requires that any waste having an asbestos content greater than 0.1 per cent is classified as ‘Hazardous Waste’, while less than 0.1 per cent can be classified as non hazardous – unless there are other contaminants present which would classify the waste as hazardous. Asbestos fibres present in concentrations greater than 0.001per cent are considered a health risk and must be dealt with as “hazardous soils” for disposal purposes.

In April 2010, the United Kingdom Accreditation Service (UKAS) reported that the testing of soils for asbestos had become the most regulated of services, which laboratories can provide to the contaminated land sector.

Around 1.8 million people are exposed to asbestos every year in the UK, according to the Health and Safety Executive. Many of the most vulnerable to exposure are known to be building contractors, tradesmen and ground clearance crews who work on the redevelopment of former asbestos-using sites.