Asbestos is the name given to a group of naturally occurring minerals found in rock formations. Three types of asbestos were mined in Australia:
- blue and
- brown asbestos.
The Northern Territory has recently provided the public and industry with asbestos information and resources through its Asbestos in the NT website.
Since exposure is potentially harmful there are a range of regulators governing contact with asbestos, its removal and disposal.
These can be found in the fact sheet Asbestos regulators and information sources in the Northern Territory .
Large deposits were mined in Western Australia and New South Wales and there were smaller operations in Tasmania and South Australia. Asbestos mining had ended in Australia by 1983 but it is still mined in large quantities in many countries across the world.
Mined asbestos only represented a small proportion of the asbestos used in Australia (about 5%) and the bulk was imported. The majority of asbestos (90%) used throughout the world, including Australia, was white asbestos.
In Australia, asbestos cement materials were first manufactured in the 1920's and were commonly used in the manufacture of residential building materials from the mid-1940's until the late 1980's. During the 1980's, asbestos cement materials were phased out in favour of asbestos-free products.
Australia banned the use or import of blue and brown asbestos or asbestos products in the mid-1980s, and banned all manufacture or import of white asbestos products in December 2003. From 31 December 2003, the total ban on manufacture, use, reuse, import, transport, storage or sale of all forms of asbestos came into force.
Asbestos fibres are strong, heat resistant and have insulating properties. Clumps of mined asbestos can be broken down in to loose fibres or fibre bundles, and can be mixed with other materials, such as cement, to produce a variety of building products. Up to 90% of the asbestos produced in or imported into Australia was used for the manufacture of building products, especially asbestos cement materials.
Asbestos fibres are not visible to the naked eye. They are very light, remain airborne for a long time, and can be carried by wind and air currents over large distances.
Asbestos fibres can be found in the air from the breakdown of natural asbestos deposits and manufactured asbestos products. Once airborne, small fibres may remain suspended in the air for some time and can be carried long distances by wind before settling down.
Large fibres and particles tend to settle more quickly. Asbestos fibres do not dissolve in water or move through soil. They are generally not broken down to other compounds and remain virtually unchanged over long periods.
Asbestos-containing building products are classified as either 'friable' (soft, crumbly) or 'bonded' (solid, rigid, non-friable).
Asbestos has been used in the manufacturing of various products. These products can be found in either friable or non-friable form. All products are also known as asbestos-containing material.
Friable asbestos products are generally quite loose and, when dry, can be crumbled into fine material or dust with very light pressure, such as crushing with your hand. These products usually contain high levels of asbestos (up to 100% in some cases), which is loosely held in the product so that the asbestos fibres are easily released into the air.
If disturbed, friable asbestos products are dangerous because the asbestos fibres can get into the air very easily, and may be inhaled by people living or working in the area.
Bonded asbestos products that have been damaged or badly weathered (including hail damage), may also become friable.
When and where friable asbestos products used?
Friable asbestos products have been commonly used in commercial and industrial settings since the late 1800's for fireproofing, soundproofing and insulation. Some friable products were also used in houses and may still be found in houses built before 1990.
Examples of friable asbestos-containing material may include:
- pipe lagging
- boiler insulation
- fire retardant material on steel work
- sprayed insulation.
Bonded (non-friable) asbestos
Bonded asbestos products are made from a bonding compound (such as cement) mixed with a small proportion (usually less than 15%) of asbestos. Bonded asbestos products are solid, rigid and non-friable, and cannot be crumbled, pulverised or reduced to powder by hand pressure. The asbestos fibres are tightly bound in the product and are not normally released into the air.
Common names for bonded asbestos products are 'fibro', 'asbestos cement' and 'AC sheeting'.
When they're in good condition, bonded asbestos products do not normally release any asbestos fibres into the air. They are considered a very low risk for people who are in contact with them, as long as appropriate safety precautions are used when they are disturbed.
However, when bonded asbestos products are damaged or badly weathered (including hail damage), areas may become friable.
Examples of non-friable asbestos containing material may include:
- asbestos cement sheet
- asbestos cement moulded products
- bitumen-based water proofing
- vinyl floor tiles.
Over time, some non-friable material may become friable.
- Examples of non-friable asbestos-containing material that can become friable as a result of a work process include:
- asbestos cement sheeting that has been crushed
- asbestos cement sheeting that has deteriorated from long-term exposure to a chemical mist.