Naturally Occurring Asbestos

What Visitors Need to Know

This information is for visitors to national forests where naturally occurring asbestos sources may be present. This information was obtained from currently available state and federal publications and resources listed below.

These best management practices are based on guidance from various federal and state agencies such as the U.S. Environmental Protection Agency; U. S. Department of Health and Human Services, Agency for Toxic Substances and Disease Registry; and the California Air Resources Board. This list should not be considered as being all inclusive.

The following document has been produced to increase awareness and safety:

Asbestos is the name given to a group of fibrous minerals that occur naturally in rock formations in the environment. Naturally occurring asbestos (NOA) is the term applied to the natural geologic occurrence of various types of asbestos, and has been found to be present in the majority of counties in California. It is commonly found in ultramafic rock formations, including serpentine, and in the soils where these rock types are located. Serpentine, the California State Rock, is found widely throughout the State. It is typically grayish-green to bluish-black in color and its surfaces often have a shiny or wax-like appearance and a slightly soapy feel.

Presence on National Forests

The Forest Service has prepared maps which identify the locations of ultramafic and serpentine rock formations on national forest lands. Not all ultramafic and serpentine rock contains asbestos. Maps also identify locations where naturally occurring asbestos has been detected to date. These maps should not be considered as providing the definitive locations of all naturally occurring asbestos on the national forests in California but they should give you an idea of where potential risks may exist. The maps were prepared based on best available information from federal and state agencies such as the California Air Resources Board, California Geological Survey, U.S. Geological Survey, and Forest Service and will be updated as new information becomes available. The maps are available below, and at local Forest Service visitor centers.

Maps of the Locations of Ultramafic and Serpentine Rock Formation on National Forests in California





https://www.fs.usda.gov/detail/r5/landmanagement/resourcemanagement/?cid=STELPRDB5363833