What is asbestos?
Asbestos is the name assigned to a group of six different fibrous materials (amosite, chrysolite, crocidolite and fibrous forms of tremolite, actinolite, and anthophyllite) occurring naturally in the environment. Asbestos minerals have long, strong fibres that can be separated and are flexible enough to be interlaced and also withstand high temperatures.
Due to these characteristics, asbestos has been used for a wide variety of manufactured products, mainly in building materials (roofing tiles, tiles and tiles, paper products and asbestos cement products), friction products (automobile clutch, Brakes, transmission components), thermo-resistant textiles, packaging, gaskets, and linings.
Some vermiculite or talc products may contain asbestos.
What happens to asbestos when it accesses the environment?
Asbestos fibres can pass into the air or water because of the degradation of natural deposits or manufactured asbestos products.
Asbestos fibres do not evaporate into air or dissolve in water. Small diameter fibres and small particles can remain suspended in the air for a long time and thus be transported long distances by wind and water before depositing.
Larger fibers and particles tend to deposit faster.
Asbestos fibres can not move through the floor. Asbestos fibres are generally not degraded to other compounds and will remain virtually unchanged for a long time.
How could I be exposed to asbestos?
We are all exposed to small amounts of asbestos in the air we breathe. These levels vary between 0.00001 and 0.0001 fibres per millilitre of air; the highest levels are usually found in cities and industrial areas.
People who work in industries that manufacture or use asbestos products or that work in asbestos mining may be exposed to high levels of asbestos. Residents near these industries can also be exposed to high levels of asbestos in the air.
Asbestos fibres can be released into the air by disturbing asbestos-containing materials during product use, demolition, maintenance, repair and renovation of buildings or homes. In general, exposure may occur only when the asbestos-containing material is disturbed in a way that releases particles or fibres into the air.
Drinking water may contain asbestos from contaminated natural sources or asbestos-containing cement pipes.
How can asbestos damage my health?
Asbestos affects mainly the lungs and the membrane that surrounds the lungs, the pleura. Breathing high levels of asbestos fibres for a long time can produce lesions that look like scars on the lungs and the pleura.
This disease is called asbestosis and occurs commonly in workers exposed to asbestos, but not in the general public.
People with asbestosis have difficulty breathing, often have a cough, and in severe cases suffer from dilatation of the heart. Asbestosis is a serious illness that can eventually lead to disability and death.
Breathing lower levels of asbestos can result in alterations in the pleura, called plaques. Pleural plaques can occur in workers and occasionally in people living in areas with high levels of environmental asbestos.
The effects of pleural plaques on respiration are generally not serious, but exposure to higher levels may lead to a thickening of the pleura that may restrict breathing.
What are the chances that asbestos will cause cancer?
It is known that breathing asbestos can increase the risk of cancer in humans. There are two types of cancer produced by exposure to asbestos: lung cancer and mesothelioma. Mesothelioma is a cancer of the pleura or tissue that surrounds the abdominal cavity (the peritoneum). Cancer caused by asbestos does not appear immediately but manifests itself after several years.
Studies in workers also suggest that breathing asbestos can increase the chances of getting cancer in other parts of the body (stomach, intestine, oesophagus, pancreas and kidneys), although this is more uncertain. Early identification and treatment of all cancer can increase the quality of life and survival of the person.
The combination of asbestos exposure and cigarette smoke greatly increases the chances of getting lung cancer. Therefore, if you have been exposed to asbestos, you should stop smoking. This may be the most important action you can take to improve your health and decrease the risk of getting cancer.
How can asbestos affect children?
We do not know whether exposure to asbestos will produce congenital disabilities or other developmental effects in humans. No congenital disabilities have been observed in animals exposed to asbestos.
The health effects of children exposed to high levels of asbestos are likely to be similar to those seen in adults.
How can families reduce the risk of asbestos exposure?
In general, asbestos-containing materials that are not disturbed or damaged do not pose a health hazard and therefore can be left untouched. If you suspect you may be exposed to asbestos in your home, contact your state or local health department or EPA regional offices to find out how to examine your home and how to find an experienced company to remove or contain fibres.
Is there a medical test to show that I have been exposed to asbestos?
Low levels of asbestos can be measured in urine, faeces, mucous fluid, or lung washes of the general population. Higher than average levels of asbestos fibres in tissues may confirm exposure but can not predict whether it will affect health.
A complete history, physical test, and diagnostic tests are needed to assess diseases related to asbestos exposure. A chest x-ray is the best tool to detect changes in the lungs that result from asbestos exposure. Pulmonary function tests and three-dimensional computerised lung probes also aid in the diagnosis of asbestos-related diseases.
What recommendations has the Australia government made to protect public health?
In 2003 the EPA banned all new use of asbestos; the uses established prior to this date are still allowed. The EPA has established regulations requiring school inspection to verify whether or not there is asbestos damaged and to eliminate or reduce exposure by either removing asbestos or covering it.
The EPA regulates the release of asbestos from plants and during demolition or renovation of buildings to prevent asbestos from entering the environment.
The EPA has proposed a limit concentration of 7 million fibres per litre of drinking water for long fibres (5 μm in length or more). The Occupational Safety and Health Administration (OSHA) has set limits of 100,000 fibres with lengths of 5 μm or more per cubic meter of air at the workplace during 8-hour, 40-hour workdays per week.