Crocidolite is a fibrous form of the mineral Riebeckite, and one of the six main types of asbestos. All six minerals that make up asbestos are characterised by fibrous crystals, which is the fundamental issue in relation to all associated health problems.
Also known as blue asbestos, crocidolite was mined in South Africa, Australia and Bolivia until the 1960s, and is widely thought to present the highest risk factor for all forms of asbestos due to its extremely strong needle-like fibres that are easily inhaled.
Crocidolite characteristics
Crocidolite is categorised as an amphibole and its fibres, although brittle by nature, can be straight or curved. Products containing crocidolite have a high ‘friability’ rate, which means they break up easily when disturbed.
Crocidolite offers less resistance to heat than the other two main forms of asbestos. It was still used in industry, however, and remains present in thousands of household products.
The strength of the fibres, combined with its fire-retardant and insulating properties, made crocidolite a widely-used resource across many industries. Construction, automotive shipbuilding, and even the tobacco industry used the substance on a regular basis.
Lorillard Tobacco patented its Micronite filter which contained crocidolite, promoting it as a healthy alternative to standard filters.
The Australian Blue Asbestos Company
The Australian town of Wittenoom is now described as a “ghost town” after more than a thousand residents, many of them miners, died from asbestos-related disease. After being the only Australian supplier of crocidolite, the town was shut down by the Government of Western Australia in 2007.
The name of Wittenoom has been removed from maps and road signs in an effort to deter visitors to this highly contaminated area, and the power grid was turned off in 2006. In 2016, only three residents remain.
Crocidolite fibres, once inhaled, are very difficult to expel. They set up life-threatening diseases and terminal cancers in later life – a fate experienced by many of the residents of Wittenoom.
What was crocidolite used for?
Crocidolite found its way into numerous household products, and was also used in industry. The flexibility of its fibres meant that it was ideal for fire-retardant clothing and rope lagging, but thousands of other products also contained the substance.
These include:
- Ceiling tiles
- Insulating boards
- Cement sheets
- Telecommunication wiring
- Thermal and spray-on insulation
- Oven gloves and fire blankets
- Guttering
- Cisterns
- Work surfaces and draining boards
Crocidolite was banned in the UK in 1985, along with brown asbestos. The physical properties of crocidolite fibres, in addition to their extreme resistance to acid, means there is a severe health risk for anyone coming into contact with the substance.
Fibres generally remain within the lungs due to their thin and brittle nature, rather than being expelled by the body, and if ingested, stomach acid will not break them down in the same way as chrysotile fibres.
Image credit By © Raimond Spekking / CC BY-SA 4.0 (via Wikimedia Commons), CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=6249389