Asbestos Exposure and Health Facts

Magnification of Asbestos fibers.

Magnification of Asbestos fibers

Naturally occurring asbestos may be a health risk if disturbed and asbestos fibers are released into the air. When asbestos-containing rocks are crushed or broken through natural weathering processes or through human activities, asbestos-containing dust can be generated. Once asbestos fibers are released into the air, they may remain airborne or in the soil for a long time. Airborne asbestos fibers may pose a health hazard because of the potential risks associated with inhalation of the fibers.

When these fibers are inhaled, over time they may cause mesothelioma (a rare cancer directly associated with asbestos exposure), lung cancer (smoking significantly increases the risk of lung cancer if one is exposed to asbestos), and non-cancer diseases such as asbestosis. All forms of asbestos fibers can cause cancer and are classified as known human carcinogens. Any exposure to a carcinogenic compound involves some risk; therefore, no "safe" exposure level has been established for asbestos. No one knows how many fibers are needed to cause cancer or other lung disease.

Diseases caused by asbestos may not be observed for twenty or more years. Being exposed to asbestos does not necessarily mean you will develop health problems. Many factors influence a person's chances of developing disease. A doctor can help you find out whether you are at risk for health problems from asbestos exposure.

Since naturally occurring asbestos is present on some national forest lands, there is a potential for your exposure to asbestos fibers on your visit to national forests in California. Natural weathering and routine human activities may disturb asbestos-bearing rock or soil and release asbestos fibers into the air. Examples of dust-generating activities include, but are not limited to:

  • Driving over unpaved roads, trails or soils
  • Riding horses or moving livestock on unpaved roads, trails, or soils
  • Recreational activities on unpaved roads, trails, or soils where dust may be generated, such as riding off-road vehicles, riding bicycles, running or hiking
  • Digging or shoveling dirt
  • Mining and quarrying operations

Health risks associated with exposure to naturally occurring asbestos are not yet fully understood. Recent studies and investigations by the U. S. Environmental Protection Agency in El Dorado County and at the Bureau of Land Management's Clear Creek Management area near Hollister, the U. S. Agency for Toxic Substances and Disease Registry, and by the University of California at Davis are increasing our understanding of the potential health risks associated with naturally occurring asbestos.