"The USGS continues to update information on asbestos localities in the U.S. due to considerable interest in this compilation effort, the first of its kind, which has already proven to have many applications for the public health, geologic, and environmental communities. This map series provides a better understanding of the geographic distribution of the geologic environments in which asbestos formed across the nation," said USGS Director Mark Myers.
USGS Open File Report 2008-1095, "Reported Historic Asbestos Mines, Historic Asbestos Prospects, and Natural Asbestos Occurrences in the Southwestern United States (Arizona, Nevada, and Utah)," is the most comprehensive compilation of natural asbestos sites in this region. The report demonstrates that previously published maps and data compilations at regional and national scales can contain inaccurate locality information and may not consider a number of published natural asbestos occurrences that appear in historic literature. This report is part of an ongoing effort to update existing national-scale databases on asbestos occurrences.
This USGS publication identifies the specific types of asbestos present in the Southwestern U.S. Previous regional to national scale maps generally do not describe the specific asbestos mineral type at any given occurrence. This map includes different types of asbestos and asbestiform minerals, but does not attempt to distinguish between substances that may or may not pose a risk to human health.
Asbestos is a term applied to a special group of fibrous silicate minerals that form as long, very thin fibers that usually occur in bundles. When handled or crushed, the asbestos bundles separate into individual mineral fibers. The type of mineral growth form is called "asbestiform". The special properties of commercial-grade asbestos-long, thin, durable mineral fibers and fiber bundles with high tensile strength, flexibility, and resistance to heat, chemicals, and electricity-have made it well suited for a number of commercial applications. This definition for asbestos is based on the properties that make it valuable as a commodity. Additional information on asbestos, including its potential health effects, is available online at the U.S. Environmental Protection Agency Web site and the Department of Health and Human Services Web site.
Naturally-occurring asbestos (asbestos that occurs in its natural geologic environment) has recently become the focus of concern and attention from the public health community, due to the potential exposures that may result if the asbestos-bearing rocks and soils are disturbed by natural erosion or human activities.