Asbestos as a Health Risks

Asbestos Health Risks

All forms of asbestos fibres are carcinogenic, the risk being dependent on the type of asbestos, the propensity of the ACM for fibre release, and the likelihood of exposure to such fibres. An ACM which is in good condition, sealed, and with a low likelihood of disturbance poses a very low-risk of causing asbestos-related disease.

The most common diseases related to asbestos exposure are:

• Mesothelioma – a cancer of the mesothelium, the fluid-filled membrane which lines the lungs (pleura), the intestines (peritoneum) and the heart (pericardium). Mesothelioma is now the most common asbestos-related disease with over 2200 people (as of 2008) developing the disease in the UK each year. Because of the long average latency period (the length of time between exposure and first onset of symptoms) of around 38 years, the annual death rate from mesothelioma is still increasing and is not expected to reach a peak for another four or five years (i.e. around 2015 to 2016). The disease is nearly always caused by exposure to asbestos, principally the amphibole types such as crocidolite and amosite.
• Lung cancer – cancerous tumours occurring inside the lungs, proven or considered most likely to have been caused by exposure to asbestos fibres. Unlike mesothelioma, where the disease is principally related to amphibole asbestos exposure, chrysotile asbestos (a serpentine fibre) is also strongly implicated in the onset of lung cancer. Because there are multiple other potential causes of lung cancer, principally from smoking and/or exposure to industrial or environmental pollutants, the death rate from this disease attributable to exposure to asbestos is difficult to determine with certainty. About 15 years ago, the HSE used to assume a comparative death rate twice that of mesothelioma (as evidenced by the increased incidence of lung cancer among asbestos workers) but it is now probably lower than a ratio of 1:1 because of the increasing death rate from mesothelioma, and the shorter latency period associated with lung cancer. About 2000 people per year are currently estimated to be dying of asbestos-related lung cancer in the UK.
• Asbestosis – progressive scarring of the lung tissue caused by asbestos exposure. Asbestosis has the best dose-response relationship of all the asbestos diseases, with a strong correlation between the amount of exposure to asbestos and the likelihood of disease occurrence. Asbestosis is actually pulmonary fibrosis triggered by exposure to asbestos fibres (as opposed to the same disease triggered by exposure to α-quartz, cristobalite or tridymite, i.e. silicosis). Asbestosis has a comparatively short latency period of 10 to 15 years. As a consequence the death rate attributable to asbestosis is now at a comparatively low level of around 120 people per annum.
• Other diseases – these include pleural plaques, considered benign and, apart from in Scotland) no longer warranting compensation, asbestos warts (a localised effect, now rare, usually attributable to prolonged handling of asbestos insulation materials) and cancers of the throat, larynx, stomach and bowel, although these are very rare.

Alexander Nicoll CCP (Asb.), AFOH

Senior Consultant, Asbestos Consultants to the Environment Ltd