Asbestos and your health
Asbestos is a naturally occurring mineral made up of many small fibres. These fibres are very strong and are highly resistant to heat, fire, chemicals and wear.
Kinds of asbestos
The most common types of asbestos fibre you are likely to find are:
- white (chrysotile)
- brown (amosite)
- blue (crocidolite).
The colour differences are very slight. Laboratory analysis is needed to identify different types of asbestos fibre.
It is now illegal to import these 3 types of asbestos in their raw fibrous states, as well as any manufactured items that contain asbestos.
In the past, the special properties of asbestos made it popular for:
- asbestos-cement sheet cladding, roofing and drainage pipes
- backing material for floor tiles and vinyl sheets
- insulation board for thermal protection, for example, around fire places
- textured ceilings and sprayed-on wall surfaces
- lagging for insulation around pipes, heaters and hot water cylinders
- vehicle brakes and clutches
- textiles
- spouting and guttering components.
Asbestos was also used in household items, such as:
- oven gloves
- ironing board pads
- simmer mats for stoves
- fire blankets.
Asbestos was mainly imported and used before the 1980s. Once the health risks of asbestos were known, its use was gradually stopped, and other materials replaced it. But products and appliances with asbestos may still be around, particularly in homes built before 1984.
How asbestos can harm health
Asbestos is a proven substance that can increase your risk of developing cancer (carcinogen). All forms of asbestos can cause cancer.
The main way people are exposed to asbestos is by breathing in air that contains asbestos fibres.
Exposure to asbestos
Asbestos causes cancer in a dose-dependent manner. You have a greater risk of developing an asbestos-related disease depending on:
- how much exposure to asbestos you had
- the length of time you were exposed to asbestos.
There has been no 'safe' lower limit of exposure identified with certainty. All exposure is thought to add to the overall risk of disease development. But the risk from a single, low-level exposure is considered to be extremely low.
Material that contains asbestos and is not damaged is not a risk just by its presence. Potential health problems happen if asbestos fibres become airborne.
The main way people are exposed to asbestos is by breathing in air that contains asbestos fibres. Small levels of asbestos fibres occur naturally in air, including as a result of:
- weathering breaking down asbestos-containing materials
- windblown soil from hazardous waste sites
- deterioration of motor vehicle clutches and brakes.
The levels of asbestos in dust and windblown soil may be higher close to:
- degrading asbestos cement clad buildings
- former sites of cement clad buildings
- waste sites where asbestos is disturbed or not properly covered.
Research into risks from asbestos exposure
The Royal Society of New Zealand and Sir Peter Gluckman released a report in 2015 report about asbestos exposure in Aotearoa New Zealand.