We are all at risk of exposure to asbestos, from which, we are unlikely to ever be free – simply because minute particles of the material are continually present as a minor pollutant in the atmosphere. It is documented that we all receive an annual exposure of 0.001 fibres per millilitre, which can be several times more in urban city environments.
However, asbestos awareness of such infinitesimally small amounts – over 1,500 fibres bundled together are smaller than one human hair – should not be a cause for alarm as they are unlikely to ever pose a risk to human health. The scale of value limits is measured on a count level thousands of times higher, based on fibres per cubic centimetre (f/cm3).
Uncovering asbestos material within the walls, ceilings or floors of residential or commercial buildings always carries a potential danger for releasing the fine fibre dust into the atmosphere when asbestos material is handled. Whenever renovations are being planned in buildings known to be over 20–30 years old, a full survey must be undertaken by authorised asbestos contractors. According to Control of Asbestos Regulations 2006, site owners and builders should, “Presume materials to contain asbestos, unless there are good reasons not to do so”.
Once the fibres are released and breathed in, the majority remain permanently embedded in the linings of the lungs (pleura). Over a lengthy gestation period of between 15 to 50 years, asbestosis disease ( fibrous lung scarring), asbestos cancer ( of the inner lung lining) or the incurable peritoneal mesothelioma ( cancer of the outer lung lining) invariably develop. However, the first asbestosis symptoms of mesothlioma are rarely caught at an early stage and patient survival rates are less than six months.
Today, the Control of Asbestos Regulations, which came into force on 13 November 2006, sets out the strict legal requirements to protect workers and others likely to be exposed to asbestos fibres at their workplace, such as during renovations or demolition of properties built up to at least the 1980s. This updates and improves on control limits set out four years earlier and amends asbestos prohibition and asbestos licensing regulations from 1992 and 1983, respectively.
The Health And Safety Executive (HSE) stipulate that worker exposure must be below the airborne exposure or Control Limit, defined as a maximum concentration of asbestos fibres in the air averaged over any continuous 4 hour period.
The Asbestos Regulations 2006 imposes a single Control Limit for all types of asbestos at 0.1 fibres per cm3 and a short term exposure limit, which should not exceed 0.6 fibres per cm3 of air averaged over any continuous 10 minute period using respiratory protective equipment.
The Asbestos Regulations require any analysis of the concentration of asbestos in the air to be measured in accordance with the 1997 WHO recommended method. (HSE).