‘Asbestos’, the Greek word for ‘not quenchable’ is the name given to a group of six fibrous minerals found naturally in many parts of the world. The asbestos mineral is the silicate group, formed from oxygen and silicon, of which there are two classes, Amphibole and Serpentine.
‘Amphibole’ consists of a polymeric structure of the silicates, silicon-oxygen bonds forming long, thin, straight fibres. The members of this group are ‘Anthophylite’, ‘Tremolite’, ‘Actinolite’, ‘Crocidolite’ ,which is more commonly known as blue asbestos and ‘Amosite’ which is better known as brown asbestos. Both the blue and brown asbestos is water repellent and is classified as ‘hydrophobic’.
‘Serpentine’ consists of a polymeric structure formed into an extended sheet, wrapped around itself and is usually curved. There is only one member of this group, known as ‘Chrysotile’ or more commonly as white asbestos, which readily absorbs water and is therefore classified as ‘hydrophilic’.
Asbestos was originally found in the 1870’s in Canada and Russia, where it is still mined today. The UK imported massive amounts, peaking in 1973 at 190,000 tonnes, although it is estimated that millions of tonnes were used nationwide, some of which still remains in our homes, schools, hospitals and work places today.
The fibres are extremely durable, being heat, acid and alkalis resistant, easily woven, good electrical and thermal insulators and therefore became known as the ‘magic mineral’. It was widely used in thermal insulation, fire protection, gaskets, seals, textiles, composites and many building materials.
Asbestos, bonded with other materials was more stable, however sprayed and lagged asbestos was banned in the UK in 1971 as the airborne fibres were proven to be dangerous. Breathing in asbestos fibres can lead to diseases, mainly cancer of the lungs and chest lining.
Dangers to Health…
A single fibre is 2000 times thinner than a human hair and can bypass the lungs’ defence system, getting deep into the alveoli, where serious damage can be done. Most fibres, especially those of blue and brown asbestos, stay in the lungs for many years causing either ‘Asbestosis’, Lung Cancer or ‘Mesothelioma’.
It takes 30-40 years to develop Asbestosis from first exposure, with the body’s defence system reacting to each of the millions of fibres, causing scar tissue, making the lung become less elastic. In trying to engulf the fibres the body’s defence mechanisms (macrophages) release powerful chemicals, which also cause damage; the process initially triggering breathlessness, which gradually gets worse, as does the Lung Cancer.
The ‘mesothelium’ is a thin membrane that surrounds the lungs, stomach and heart, hence cancer in this membrane is called a ‘mesothelioma’ and is virtually only caused by asbestos exposure. Cancer here is un-treatable, extremely painful and most people die within one year of first diagnosis.
There are 3,000 deaths each year in the UK as a direct result of asbestos exposure which underlines the critical importance of managing asbestos correctly.