White chrysotile asbestos – just what is the level of risk if the fibre dust particles are discovered in your home or workplace? Different groups and organisations, often with an asbestos awareness and understanding of the potential risk, can sometimes present a conflicting viewpoint.
Following an environmental safety survey, which confirmed the presence of white asbestos in a housing association ground floor bathroom, the occupying tenant was increasingly concerned over the flakes becoming airborne as they fell away from the ceiling.
“Not an unacceptable risk”
The surveyor’s report stated that asbestos “does not necessarily create an unacceptable risk” but does advise “remedial action” to be carried out. However, since the report was issued in May, the housing group which owns the property has yet to undertake any repairs.
A spokesman for the group admits there are “traces of asbestos” in the bathroom ceiling but insists there is no risk as the asbestos is “sealed” and confirms repairs are due to shortly take place.
White asbestos has been generating confusion and misunderstanding ever since the UK banned blue and brown asbestos in 1985. At this time, the building industry was allowed to continue using insulation products made with white asbestos because the chrysotile fibres were categorised as ‘low risk’.
Why is white asbestos considered less harmful than other types?
Medical research pointed to the critical difference between ‘amphibole’ and ‘serpentine’ asbestos fibres, the ability of the immune system to break down the different fibre types and the time taken to eliminate from the body.
Blue and brown asbestos fibres are classified as amphibole – straight, needle-like in shape. They embed more stubbornly in the lung linings and are almost impossible for the body to clear. White asbestos fibres are the only category of serpentine fibre – curly in shape – which the body can clear more easily over a shorter period of time.
The research suggested that unlike the more robustly shaped fibres of brown and blue asbestos, the curly fibre forms of white asbestos break down more easily into smaller particles. Less congested lungs also means that the body is also more easily able to clear out the longest fibres.
It was therefore, argued that low exposures may not necessarily present a detectable risk to health and the chrysotile fibres of white asbestos are not as likely to trigger cancerous cell activity and develop into fatal mesothelioma tumours. Based upon the initial research suggestion that chrysotile fibres are comparatively ‘low-risk’, a number of organisations – even entire countries and continents – have since justified their position on the safety and use of the mineral.
Severe tissue inflammation
However, there is evidence that regular and prolonged exposure to chrysotile can and does produce asbestos-related cancer and asbestosis disease. The presence of asbestos fibres can initially cause severe tissue inflammation, leading to scarring of the lung linings (pleural plaques), thickening of the lungs themselves (pleural thickening) and a build up of liquid (pleural effusion).
Many official institutions, such as the World Health Organisation (WHO) and the World Trade Organisation recognise the unique curly shape of white chrysotile is different from other fibre types, but still underline the potentially fatal health risks of long term exposure.
Extent of exposure and risk
Imports of white asbestos into the UK were finally halted in November 1999 and officially banned by EU directive in January 2005. However, as recently as 2011, the UK has been repeatedly called upon to comply with guidance set out by a 2009 European Asbestos Directive, which addresses the issue of “sporadic and low intensity exposure to asbestos” rather than simply measuring the extent of exposure and risk.
In May of the same year, HM Government Office for Science responded to an enquiry into white asbestos risk and a possible change of law with the following, “ …it is not possible to determine a threshold level below which exposure to ‘pure’ chrysotile could be deemed ‘safe’ for human health. On the evidence available, there is no justification for an imminent change to the international scientific consensus on the classification of chrysotile as a Class 1 carcinogen.”
Under the Control of Asbestos at Work Regulations (CAR 2006/12), the Health And Safety Executive (HSE) clearly set out the precise requirements for the control and management of white asbestos, which may be left undisturbed and encapsulated rather than attempt its removal and risk releasing fibres into the air.