In the past few years, there have been several instances in which disturbance of sites containing naturally-occurring asbestos, via construction or other land use changes, has posed a potential health threat. As one tool for reducing such problems, on March 13, 2008, USGS released its fourth in a series of reports on US sites with naturally-occurring asbestos, covering 121 locations in AZ, NV, and UT.
- "Reported Historic Asbestos Mines, Historic Asbestos Prospects, and Natural Asbestos Occurrences in the Southwestern United States (Arizona, Nevada, and Utah)": Press release;  Web site. 
This brings the total number of locations listed in the US to 542, with many more to come with the expected release in late 2008 of the fifth report, for CA, OR, and WA. Release of the final report, on AK, is expected to follow. HI has no known natural asbestos sites.
The reports consolidate and correct previously available (though sometimes obscure) information, and pin down the specific type(s) of asbestos at each site.
For more information, see the SEJ TipSheet of Aug. 1, 2007.