What is asbestos?What is it, where does it come from and why is it so hazardous?
Where does asbestos come from?
Many people think that asbestos is manmade. It is not. Asbestos is the name for a variety of naturally occurring silicate minerals. These minerals or rocks form naturally and contain fibrous strands or asbestos fibres. These minerals and fibrous rock formations occur in many parts of the world. Today the main areas of commercial asbestos mining are located in Russia and China. In the past Canada and Southern Africa were also amongst the biggest asbestos mining locations.
Asbestos containing rock once mined is crushed and milled at the mining site to produce various grades of raw asbestos fibre. This raw asbestos fibre is then transported to factories throughout the world to be combined with other ingredients and produce various asbestos containing materials.
Asbestos fibre is mechanically strong. Side by side asbestos is stronger than steel. Asbestos is heat resistant, flame retardant and has very high thermal property making it an excellent insulation material. Asbestos has good acoustic insulation properties making it ideal for sound proofing materials. Asbestos is also highly resistant to chemical attack and is virtually indestructible. Due to its fibrous nature, asbestos can be woven into textiles, fabrics and paper. Asbestos can be easily added to other products and can be used to reinforce cements, boards and plastics. Its applications are unlimited.
How many types of asbestos are there?
There are six types of asbestos. These are:
- Chrysotile (Commonly known as “White” asbestos)
- Amosite (Commonly known as “Brown” asbestos)
- Crocidolite (Commonly known as “Blue” asbestos)
Out of these six types of asbestos the first three – White, Brown and Blue asbestos are the most common. Although the other types have been mined and used, they are relatively rare. There are two distinctive shapes of asbestos fibre. The first is “Serpentine” which are curly, flexible fibres. White asbestos falls into this category.
The remaining five asbestos fibre types are classed as “Amphibole” which are needle like fibre shape. All asbestos types and fibre shapes are equally as hazardous.
Why is asbestos so hazardous?
Asbestos fibres can be split into smaller and thinner fibres when disturbed. When initially mined these fibre strands divide into visible fibres and bundles. During the processes of refining asbestos to be used for commercial purposes this splitting continues reducing the fibres size to microscopic levels. Asbestos fibres can become so small that if they become airborne, they can remain suspended in the air for up to two weeks. This is why asbestos containing materials which are disturbed creating airborne asbestos fibre are such a problem.
Airborne asbestos fibre can then be inhaled and pass undetected by the human respiratory defences and into the body. Asbestos being virtually indestructible cannot be removed by the body and can cause asbestos related disease.