The middle decades of the twentieth century are often referred to as the ‘peak years’ of asbestos use as an insulating and strengthening material.

Although the mineral had been in use from the 1800s, it was between the 1940s and 1980s, which saw asbestos fibres incorporated into an estimated 3,000 products in almost every type of industrial and commercial application.

Regular exposure…

Despite early attempts at asbestos legislation in the 1930s, until the first ban in the mid 1980s many thousands of workers, mainly concentrated in the factories, workshops and shipyards of the North of England and the Midlands, would continue to be regularly exposed to airborne asbestos fibre dust during their working lives.

From the 1960s onwards, there was growing asbestos awareness of the long term risks of exposure and the onset of asbestosis disease or the fatal, malignant mesothelioma cancer. However, many company employers neglected to inform their workforce of the health hazards of asbestos exposure nor provide any form of protective equipment or clothing.

Six asbestos types…

Although the three main asbestos mineral types of chrysotile ( white), amosite ( brown) and crocidolite ( blue) were known to be frequently used, they were not the only asbestos fibres appropriated as an inexpensive source of insulating, strengthening material.

There were six asbestos types known to be used :

• Amosite
• Crocidolite
• Chrysotile
• Anthophyllite
• Tremolite
• Actinolite

Each had their own distinct fibre characteristics, which were most applicable for different types of products.

Amosite – a trade name acronym of Asbestos Mines of South Africa – and Crocidolite are the most well known of the highly toxic asbestos minerals, which were first banned in 1985.

Amosite

Amosite contains straight, high tensile strength fibres, which can resist temperatures of up to 900ºC and its bundle forms could be spun to produce pipe insulation material and fireproofing.

Crocidolite

Another high tensile strength mineral, Crocidolite forms much finer lengths of fibre and was primarily used in asbestos-cement products, filters, gaskets as well as general insulation products.

Chrysotile

The most widely used of all asbestos forms, Chrysotile is composed of curly fibres, and being different from the straight needle fibres of amosite and crocidolite, is often considered a ‘low risk’ asbestos because the fibre particles may be more easily expelled from the lungs over a shorter period of time. The fine fibres were mostly spun for use in textiles, high thermal and electrical insulation and many construction industry products, such as cement, fireproof boards, gaskets, adhesives, putty, etc

White asbestos continued to be used into the 1990s by the building industry until a total import ban in the UK was imposed in 1999 but continues to be mined and imported by a number of developing countries around the world.

Anthophyllite

Anthophyllite is a straight fibre asbestos mineral with high chemical resistance and high thermal and electrical insulation capacity, which was used for producing adhesives, plastics, insulation, filling reinforcement materials, etc.

Tremolite and Actinolite

Further straight fibre types found only in natural materials, such as talc, and used in a variety of commercially available products.