Many of us know of asbestos and how bad it is for our health, but the majority don’t know what it really is and where it came from. In the early 1900’s in the time of new technologies and using steam, kerosene and electricity, there were many new fire hazards being produced. When casualties at schools, office buildings and ships began rising into the hundreds, the search for a new insulating material that was non-combustible began.
Asbestos is a naturally occurring mineral made up of many small fibres and can be pulled into a fluffy consistency. It is soft and flexible yet resistant to heat, electricity and corrosion, making it an excellently useful material for insulation. It is not a single mineral, rather a group of silicate minerals that share the same fibrous nature. Raw asbestos is made by crushing asbestos ore to separate the other minerals, it is then processed until it is soft and woolly in consistency.
In its pure form, it can be made into paper, felt or rope, as well as mixed into cement, drywall, plastics and paints. However, when broken down it is 50-200 times thinner than human hair, it can float in the air for a long time undetected, not visible to the naked eye.
There are three main types of asbestos that builders may come across whilst working; white (chrysotile), blue (crocidolite) and brown (amosite).
White asbestos is the most commonly used type of asbestos, it is usually fine in texture, flexible and has heat resistant properties, making it ideal for use in cement, brake pads/linings and roofing materials.
Blue asbestos is very thin and if inhaled can easily be lodged in the lungs, it’s thin fibres and brittleness makes it the most harmful form of asbestos as it breaks down easily and can become loose and easily ingested.
Brown asbestos is a particularly strong and heat-resistant type of asbestos that is mainly used in cement, plumbing and electrical insulation. Whilst all types are harmful, this type has a higher cancer risk and is highly toxic.
The history of asbestos in New Zealand begins in the late 1930’s when it was first imported to be used with building products such as cement, with the locally manufactured asbestos-cement products containing around 5-15% asbestos. Most houses built in the 1950s-70s contained tiled or sheet asbestos-cement roofing as it was easily moulded and ideal for corrugated roofing. As it’s uses developed, applying asbestos as a spray coating on ceilings and walls for decoration was common, as well as being mixed with vinyl sheet and tile flooring. When breaking down the amount used in New
Zealand, in terms of kilograms per capita per year, it was much lower than many countries such as Australia, Canada and Germany.
After years of research and understanding the effects asbestos has on the human body, importing raw asbestos into New Zealand was banned in 1984, but the importation of asbestos-containing products into the country wasn’t outlawed until October of 2016.