Amosite is characterised by needle-like fibres that offer good resistance to heat, and have strong insulating properties. For these reasons, it was a common addition to construction materials in many countries around the world.
‘Amosite’ is actually an acronym and trade name for grunerite, a member of the amphibole group of minerals. It was largely mined in the Transvaal Province in South Africa, which is where the name originated – Asbestos Mines of South Africa (AMOSA).
This dangerous substance remains in many of our older buildings today, posing a danger to workers or members of the public undertaking DIY and refurbishment, renovation, or demolition work.
Anyone carrying out this type of work should undergo asbestos awareness training. It provides the knowledge needed to identify asbestos in its varying forms, and act in accordance with the Control of Asbestos Regulations, 2012.
Banned in the 1980s
In 1985 the Asbestos Prohibitions Regulations introduced a ban on amosite, along with crocidolite (blue asbestos). Amosite is generally considered to be the second most dangerous form of asbestos after crocidolite, and creates a high risk factor for life-threatening disease for anyone who has breathed in its fibres.
It is said that, when intact, asbestos does not pose a serious danger. Considering the length of time these asbestos-containing materials have been in place, however, even a small degree of disturbance to the fabric of an older building could release tiny fibres into the air.
Specific health risks of amosite
Being rod-like in nature, amosite fibres can easily penetrate the lung wall when breathed in, and offer a serious risk to health when airborne. The body finds it difficult to expel the fibres once inhaled, and life-threatening disease can be set up several decades later.
Life-limiting illnesses including asbestosis and pleural thickening, and terminal lung cancers, are caused by exposure to asbestos, sometimes decades before any of the symptoms are felt.
Products containing brown asbestos
Building products requiring high tensile strength were often manufactured using amosite. These included:
- Roof tiles
- Ceiling and floor tiles
- Cement sheets
- Electrical insulation
- Pipe lagging
- Chemical insulation
- Asbestos insulating board
Because of their resistance to fire, ceiling tiles containing amosite were commonly used in schools and other educational buildings, and have been the subject of debate for many years.
Asbestos Mines of South Africa
South Africa has one of the highest rates of mesothelioma in the world, due to its extensive mining of amosite, crocidolite and chrysotile. It was the only country that mined all three main types of asbestos, with production at its highest during the 1960s and 1970s.
The use of heavy machinery including pneumatic drills, significantly increased the danger for South African workers who became seriously ill in large numbers. The health effects of working with asbestos were finally recognised in 2008, when legislation was introduced to prohibit the use, manufacture, import and export of asbestos and asbestos-containing materials in South Africa.