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Asbestos

What is asbestos?

Asbestos is the name given to a group of six different fibrous minerals that occur naturally in the environment. Asbestos fibers are too small to be seen by the naked eye. They do not dissolve in water or evaporate. They are resistant to heat, fire, and chemical or biological degradation.

Asbestos is also used in many commercial products, including insulation, brake linings, and roofing shingles.

What are the types of asbestos?
The two general types of asbestos are amphibole and chrysotile (fibrous serpentine). Chrysotile asbestos has long, flexible fibers. This type of asbestos is most commonly used in commercial products. Amphibole fibers are brittle, have a rod or needle shape, and are less common in commercial products. Although exposure to both types of asbestos increases the likelihood of developing asbestos-related diseases, amphibole fibers tend to stay in the lungs longer. They also are thought to increase the likelihood of illness, especially mesothelioma, to a greater extent than chrysotile asbestos.

What is naturally occurring asbestos?
Naturally occurring asbestos refers to those fibrous minerals that are found in the rocks or soil in an area and released into the air by:

• routine human activities or
• weathering processes.

If naturally occurring asbestos is not disturbed and fibers are not released into the air, then it is not a health risk. Asbestos is commonly found in ultramafic rock, including serpentine rock, and near fault zones. The amount of asbestos that is typically present in these rocks ranges from less than 1% up to about 25%, and sometimes more. Asbestos can be released from ultramafic and serpentine rock if the rock is broken or crushed.

In California, ultramafic rock, including serpentine rock, is found in the Sierra foothills, the Klamath Mountains, and the Coast Ranges. This type of rock is present in at least 44 of California’s 58 counties. Not all ultramafic rock contains asbestos; it has the potential to contain asbestos. Environmental testing can determine if a rock contains asbestos.

Asbestos Exposure

What is asbestos exposure?
Asbestos exposure results from breathing in asbestos fibers. If rocks, soil, or products containing asbestos are disturbed, they can release asbestos fibers into the air. These fibers can be breathed into your lungs and could remain there for a lifetime. Asbestos exposure is not a problem if solid asbestos is left alone and not disturbed.

Who is at risk for asbestos exposure?
Almost everyone has been exposed to asbestos at some time in their life. Higher levels of asbestos are more common near:

• an asbestos mine or factory
• a building being torn down or renovated that contains asbestos products
• a waste site where asbestos is not properly covered up or stored to protect it from wind erosion, or
• an area containing naturally occurring asbestos that has been disturbed through activities that crush asbestos-containing rock or stir up dust in soils that contain asbestos fibers.
  

In indoor air, the concentration of asbestos depends on whether:

• asbestos was used for insulation, ceiling or floor tiles, or other purposes, and whether these asbestos-containing materials are in good condition or are deteriorated and easily crumbled
  activities in the house, such as repairs and home improvements have disturbed asbestos-containing materials, or
• asbestos has been brought into the home on shoes, clothes, hair, pet fur or other objects.
  

Outdoor air concentrations of asbestos can also contribute to indoor air asbestos levels.

Health Effects of Asbestos Exposure
What is the likelihood of developing health problems from asbestos exposure?

Being exposed to asbestos does not mean you will develop health problems. Many things need to be considered when evaluating whether you are at risk for health problems from asbestos exposure. The most important of these are:

• how long and how frequently you were exposed
• how long it has been since your exposure started
• how much you were exposed
• if you smoke cigarettes (cigarette smoking with asbestos exposure increases your chances of getting lung cancer)
• the size and type of asbestos you were exposed to
• other pre-existing lung conditions
  

A doctor can help you find out whether you are at risk for health problems from asbestos exposure.

Are children at greater risk for asbestos-related diseases?

Children have more time to be exposed and develop asbestos-related diseases. Medical experts do not know whether lung differences may cause a greater amount of asbestos fibers to stay in the lungs of a child who breaths in asbestos compared with the amount that stays in the lungs of an adult.

What are the symptoms of asbestos-related disease?
Most people don’t show any signs or symptoms of asbestos-related disease for 10 to 20 years or more after exposure. When symptoms do appear, they can be similar to those of other health problems. Only a doctor can tell if your symptoms are asbestos-related.

What are some types of asbestos-related diseases?
Asbestos-related diseases can be: non-cancerous

Asbestosis is scarring of the lungs. It is typically caused by very high exposure levels over a prolonged period of time, as seen in work-related asbestos exposure. Smoking increases the risk of developing asbestosis. Some late stage symptoms include progressive shortness of breath, a persistent cough, and chest pain.

Pleural changes or pleural plaques include thickening and hardening of the pleura (the lining that covers the lungs and chest cavity). Most people will not have symptoms, but some may have decreased lung function. Some people may develop persistent shortness of breath with exercise or even at rest if they have significantly decreased lung function.

Asbestos-related diseases can be:cancerous

Lung cancer is cancer of the lungs and lung passages. Cigarette smoking combined with asbestos exposure greatly increases the likelihood of lung cancer. Lung cancer caused by smoking or asbestos looks the same. Symptoms for lung cancer can vary. Some late stage symptoms can include chronic cough, chest pain, unexplained weight loss, and coughing up blood.

Mesothelioma is a rare cancer mostly associated with asbestos exposure. It occurs in the covering of the lungs and sometimes the lining of the abdominal cavity. Some late stage symptoms include chest pain, persistent shortness of breath, and unexplained weight loss. Coughing up blood is not common.

Can asbestos-related disease be serious?
Asbestos-related disease can be serious, though not everyone exposed to asbestos gets health problems. Health problems that develop may range from manageable to severe—and some may cause death.

How common are asbestos-related diseases?
Mesothelioma is relatively rare. According to the American Cancer Society, there are about 2,000 – 3,000 new cases per year in this country. It is most common in asbestos-related work exposure though it has been observed in certain communities worldwide where people have had lifetime exposures to naturally occurring asbestos.
Lung cancer from all causes affects about 61 out of every 100,000 Americans a year. According to the American Cancer Society, it is the leading cause of cancer-related death in both men and women and accounts for about 29% of all cancer deaths. Asbestos exposure is only one of many potential causes of lung cancer. Cigarette smoking is by far the most important risk factor for lung cancer. Cigarette smoking combined with asbestos exposure greatly increases the likelihood of lung cancer.

To see the rest of this brochure from the Agency for Toxic Substances and Disease Registry, please click here: http://www.atsdr.cdc.gov/NOA/Asbestos-and%20Health.pdf