Despite today’s high degree of asbestos awareness, councils, construction and demolition firms can still underestimate the quantities of asbestos still concealed in millions of properties around Britain.

A recent example involved the demolition of eight bungalows near Wrexham, north Wales where an initial survey on the amount of asbestos needed to be removed was found to be inadequate. More than half of the £30,000 overspend on the project involved the removal of the additional amount of asbestos discovered, which led to a month’s delay in completing the project.

Artex coating

According to the initial asbestos report, the amount of asbestos present in the Artex coatings applied to the cavity walls was underestimated by nearly 80 per cent. As required by the Control of Asbestos Regulations, the report instructs that the asbestos – described as “low risk” – must be removed before demolition can proceed.

Underestimating the quantities of asbestos hidden in local authority buildings is not uncommon. An additional £1.3 million was calculated to be needed for the demolition of four multi-storey tower blocks in Dumbarton, Scotland, because they were found to contain “unexpectedly high” levels of asbestos. According to the local authority the levels of asbestos found were also “far beyond the normal content expected in buildings of their age and type” and “not fit to provide tenants with the modern standards they deserve.”

Invisible fibre dust particles

The discovery of asbestos containing materials (ACMs) in older council property can still be a shock to many millions of tenants who may have lived at the same house for many years. Entire generations of families living in council estate properties may have been breathing in invisible fibre dust particles for decades.

From 1945 onwards, a rapid post-war reconstruction programme enabled homes to be quickly and cheaply built. All types of homes, from private dwellings to local authority housing were constructed with AIB (asbestos insulation board), asbestos cement roofing, boiler and pipework lagging.

Through the 1950s, 60s and 70s, the application of decorative ceiling and wall plastering (Artex) was widespread, as well as loose asbestos sprayed loft/roof insulation and cavity wall infill.

Three in five houses contained asbestos

When the first UK ban on the use of asbestos (brown amosite and blue crocidolite) was introduced in 1985, a survey conducted in the same year by the Association of Metropolitan Authorities (AMA) estimated that some asbestos containing materials (ACMs) were present in four million council homes, eighty per cent of 10,000 schools and over three quarters of social services buildings surveyed.

However, the practice of using insulation materials made from white asbestos fibres is known to have continued in some areas right through until the 1990s at least. In August 2011, a Freedom of Information request revealed that around 12,000 council properties surveyed in the Stoke On Trent area, of which, more than three in five were found to contain asbestos.

According to construction industry experts, any property – especially in the public sector – built or renovated up until the end of the twentieth century is liable to contain between 5 per cent and 30 per cent of asbestos containing materials.

No threshold risk level

Today, the problem of hidden asbestos only comes to light when demolition or refurbishment projects are underway, and highlights not just the ever present dangers of potential exposure to building and demolition contractors. It can also still be commonly believed that white chrysotile asbestos, which was only banned from import in 1999, is a ‘low risk’ material.

However, white chrysotile asbestos has been confirmed as a Class 1 carcinogenic substance at the Government Office for Science who have said that it may not be possible “to determine a threshold level” below which exposure would be considered not a risk to health.

The term ‘low risk’ may only be properly applied if white asbestos is found to be in a strictly undisturbed state, good condition (not deteriorated over time), and is to be properly contained and managed according to the Control of Asbestos Regulations (CAR) 2006/12.

It is believed that there could be between half a million to six million properties around the UK still harbouring the deadly fibre materials within their walls, ceilings, roofs and floors. The Health & Safety Executive estimate that more than 1.8 million people – mostly involved in the building trades – continue to be annually exposed to asbestos, and more than 2,000 cases of mesothelioma are diagnosed every year.