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.

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.

Keep exposure to asbestos as low as possible.

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.

Asbestos exposure in New Zealand: Review of the scientific evidence of non-occupational risks — Royal Society of New Zealand (external link)

Inhaling significant amounts of airborne asbestos causes:

scarring of lung tissue (asbestosis)
malignant tumours, which are cancers that develop around the lungs or intestines (mesothelioma)
thickening of membranes around the lungs (pleural plaques)
cancer of the lung, larynx and ovary.

Smoking can increase the risk of developing lung cancer following exposure to asbestos.

Symptoms of diseases related to asbestos

Symptoms include breathing difficulties and scarring of the lungs. These can be detected by x-ray.

Effects of ingesting asbestos

The harmful effects of ingesting asbestos have not been clearly documented, but it has been shown that few fibres are able to penetrate the gastrointestinal tract. As a result, the non-gastrointestinal effects from oral exposure (ingested through food or drink) to asbestos are unlikely. There is no consistent evidence that ingested asbestos is hazardous to health.