Asbestos is all the same, right? It’s all nasty, bad stuff and it’s bad for your health? Well, yes that is correct – all six types of asbestos fibres are considered hazardous. So, you’ll be surprised to learn that asbestos is actually a naturally occurring material. In fact, asbestos is just the general name given to the six types of fibrous silicate minerals that have the common properties of being resistant to fire, heat and electricity, as well as absorbing sound. These minerals were mined for many decades before being banned in most countries when we discovered how dangerous the tiny fibres could be when airborne and inhaled into human lungs. Asbestos is however still used in India, Russia and China amongst others.

WorkSafe estimates that around 170 people die of asbestos-related illnesses each year in New Zealand. That’s around half the annual road toll! 

Asbestos fibres are easily inhaled, because they’re so tiny, so tiny in fact, that you can’t see individual fibres with the naked eye. There are six types belonging to two mineral families - serpentine and amphibole. The following are the three that were most commonly used in consumer and building materials before the 1990s:


Chrysotile (White)

The single asbestos type from the serpentine family. These fibres are white, fine in texture, short and curly, they are flexible and have high heat resistance properties.  You will find them in many common building materials used in New Zealand, particularly before the 1990s. They are however still present today in some products. This mineral is found most commonly in roofs, ceilings, walls, floors and insulation of older buildings as well as in automobile friction products such as brake pads, brake linings and clutches. They are also commonly found in gaskets and boiler seals. It was the most commonly used type of asbestos and therefore accounts for the greatest number of asbestos-related health problems in New Zealand.


Amosite (Brown)

Mined mostly in Africa, Amosite is a particularly strong and heat-resistant type of asbestos, so it was used commonly in building materials, such as cement sheet, insulation board, electrical insulation, ceiling tiles and thermal insulation products. This was before it became illegal to use or manufacture asbestos products in New Zealand. Of all the types of asbestos, exposure to amosite is known to have a higher incidence of cancer.


Crocidolite (Blue)

Like a crocodile’s bite, it’s as nasty and sharp-toothed as it sounds. It’s named for its naturally long and sharp mineral form and it’s the most brittle of all asbestos, so it can break down and become airborne very easily. However, it is one of the least-used types of asbestos in consumer products. It is blue-ish in colour, so it is often referred to as ‘blue asbestos’. Crocidolite may be responsible for more deaths than any other type of asbestos, because its fibers are extremely thin, causing them to lodge more easily in lung tissue.


The other three types of asbestos were not commonly sold commercially, but are found as contaminants in other types of asbestos and are just as hazardous to your health as the first three types of asbestos:



These fibres have a high magnesium content and can range from creamy white to dark green depending on iron content. They’re associated with the development of malignant mesothelioma, an asbestos related cancer. It was not used commercially on its own but can be found as a contaminant in other types of asbestos minerals, and is most commonly found in paint, sealant and talc. Tremolite was also considered a useful mineral because its properties meant it could be woven into cloth.



Also commonly found in paint, sealant and plasterboard before the 1990s, actinolite expands when heated so it was considered a great insulator. Naturally it was used often in insulation and fire-proofing products. Actinolite is very similar in its physical properties, such as colour and shape, to tremolite.



These fibres are typically a grey-brown colour, and despite not being used as a commercial product, it is a common contaminant in composite flooring. It was also regularly found in talcum powder. It’s not as commonly associated with asbestos-related cancers, but there is still a clear link between exposure to anthophyllite and a risk of developing mesothelioma.


So, which asbestos is the most dangerous?

While all forms of asbestos are known to have health risks, crocidolite is considered by many to be the most dangerous to your health. Its straight, fine, sharp needle like fibres are easily inhaled when airborne, where they come into contact with lung tissue.


How do I identify asbestos?

Even though the six different types of asbestos have varying colours and forms, none can be identified by the human eye. They are both odourless and tasteless. The fibres are so small, that they can be up to 700 times smaller than a human hair! This makes them very dangerous when airborne, because you don’t know when you’re inhaling or ingesting them. The easiest way to find out whether your house or building has asbestos containing materials or products present is to get an expert in to assess. They will take samples if they suspect there are any asbestos building materials present.


Due to the health risks it’s important that you don’t attempt to investigate yourself. So if you suspect that your home or business has asbestos, you’ll need to call in the experts. 

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