Here we provide a list of answers to common asbestos-related questions. This is not a comprehensive list and is provided as a starting point. If you have further questions, please contact the ARP and we will be happy to help you get answers.
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 is Libby Amphibole (LA)?
Vermiculite was discovered in the Rainy Creek Mining District of Lincoln County, Montana, in 1916 by E.N. Alley. Alley formed the Zonolite Company and began commercial production of vermiculite in 1921. W.R. Grace purchased the mining operations in 1963. They greatly increased production of vermiculite which resulted in increased utilization of vermiculite in many forms of commercial products with one of the most popular being Zonolite insulation.

It was realized that the vermiculite ore bodies from the mine site called “Zonolite Mountain” contained amphibole asbestos at concentrations ranging up to nearly 100% in selected areas. Thus virtually all vermiculite from Zonolite Mountain was contaminated with the most toxic form of asbestos called Libby amphibole asbestos. These asbestiform mineral fibers have a chemical composition that transition between winchite, richterite, and tremolite, while also containing trace amounts of actinolite and ferro-edenite. The mineralogy of Libby amphibole asbestos is very unique both chemically and structurally. In addition, the Libby amphibole asbestos diseases have many unique characteristics.

What are the types of asbestos?
The two general types of asbestos are chrysotile (fibrous serpentine) and amphibole. 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 one of the following methods:

  • Routine human activities
  • 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 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 only has the potential to contain asbestos. Environmental testing can determine if a rock contains asbestos.

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 could be exposed to asbestos?
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.
  • 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.
  • 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.
What factors could influence the risk of developing an asbestos-related disease?

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 to which you were exposed.
  • Other pre-existing lung conditions. A doctor can help you determine whether you are at risk for health problems from asbestos exposure.
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?


  • 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.


  • 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 be removed from the lungs?

No known method exists to remove asbestos fibers from the lungs once they are inhaled. Some types of asbestos are cleared naturally by the lungs or break down in the lungs.

What can I do to reduce my exposure to asbestos?
Limit exposure by taking the following steps if you live in an area where naturally occurring asbestos has been disturbed and is likely to become airborne:

  • Walk, run, hike, and bike only on paved trails.
  • Play only in outdoor areas with a ground covering, such as wood chips, mulch, sand, pea gravel, grass, asphalt, shredded rubber, or rubber mats.
  • Pave over unpaved walkways, driveways, or roadways
  • Cover asbestos-containing rock or soil in gardens and yards with asbestos-free soil or landscape covering.
  • Pre-wet garden areas before digging or shoveling soil.
  • Keep pets from carrying dust or dirt on their fur or feet into the home.
  • Remove shoes before entering your home to prevent tracking in dirt.
  • Use doormats to lower the amount of soil that is tracked into the home.
  • Keep windows and doors closed on windy days and during nearby construction.
  • Drive slowly over unpaved roads.
  • Use a wet rag instead of a dry rag or duster to dust.
  • Use a wet mop on non-carpeted floors.
  • Use washable area rugs on your floors and wash them regularly.
  • Vacuum carpet often using a vacuum with a HEPA filter.
  • Inspect your home for deteriorating asbestos-containing insulation, ceiling, or floor tiles.
  • Do not disturb asbestos-containing insulation, ceiling, or floor tiles; hire a trained and certified asbestos contractor to remove the materials.
  • Ask your employer if you are working with materials or in an environment containing asbestos. If you are, make sure you are properly protected from asbestos exposure.
What is a Superfund Site?

Superfund, officially The Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), was enacted by Congress on December 11, 1980. This law created a tax on the chemical and petroleum industries and provided broad federal authority to respond directly to releases or threatened releases of hazardous substances that may endanger public health or the environment. Over five years, $1.6 billion was collected and went to a trust fund for cleaning up abandoned or uncontrolled hazardous waste sites.


  • Establishes prohibitions and requirements concerning closed and abandoned hazardous waste sites.
  • Provides for liability of persons responsible for releases of hazardous waste at these sites.
  • Establishes a trust fund to provide for cleanup when no responsible party can be identified.

The law authorizes two kinds of response actions:

  • Short-term removals, where actions may be taken to address releases or threatened releases requiring prompt response.
  • Long-term remedial response actions, that permanently and significantly reduce the dangers associated with releases or threats of releases of hazardous substances that are serious, but not immediately life threatening. These actions can be conducted only at sites listed on EPA’s National Priorities List (NPL).

CERCLA also enables the revision of the National Contingency Plan (NCP). The NCP provides the guidelines and procedures needed to respond to releases and threatened releases of hazardous substances, pollutants, or contaminants. The NCP also establishes the NPL. CERCLA was amended by the Superfund Amendments and Reauthorization Act (SARA) on October 17, 1986.

What is the National Priorities List?
The National Priorities List (NPL) is the list of national priorities among the known releases or threatened releases of hazardous substances, pollutants, or contaminants throughout the United States and its territories. The NPL is intended primarily to guide the EPA in determining which sites warrant further investigation.

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How can I stay informed?

ARP Hotline: (406) 291-5335
ARP Office: (406) 291-2442

Where can I get more information on screening, diagnosis and treatment of asbestos-related diseases?

Contact the CARD Clinic for updated information on screening, diagnosis and treatment of asbestos-related diseases.

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Should my family or I get screened for asbestos-related diseases?

The CARD Clinic recommends screening for any person that lived, worked or played in Lincoln County for at least 6 months prior to 2003. Contact the CARD Clinic for more information.

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