Naturally Occurring Asbestos: Public Health and Civil Litigation Considerations


Most people associate the term "asbestos" with an ingredient removed from commercial or building products years ago. Few think about in connection with hiking, horseback riding or gardening. Yet, asbestos is a fibrous mineral naturally occurring in rock. Over the past few years, knowledge about the natural occurrences of asbestos in soil and rock has been increasingly documented.

Asbestos is usually found in ultramafic rock, which includes serpentine rock, and the amount of asbestos found in ultramafic rock can range from 1% to 25%. Therefore, some rocks may contain relatively large quantities of asbestos. If these rocks are broken or crushed, asbestos can be released into the surrounding soil or air. These natural occurrences of asbestos raise issues for both the public health and private litigation arenas.

In the public health arena, the focus is on the health of people who live in areas where naturally occurring asbestos is present. For example, ultramafic rock of the kind that may contain asbestos can be found in 44 of California's 58 counties, and in the foothills of the Sierra Mountains. Recently, a study conducted by the University of Nevada-Las Vegas (UNLV) found naturally occurring asbestos in a large area of southern Nevada. This study assisted in indefinitely delaying a $490 million highway project to alleviate traffic congestion near Las Vegas so that the extent of the naturally occurring asbestos rock could be assessed, and the potential risk to residents and tourists from construction activity in the rock considered.

In 2013, UNLV received funding to investigate naturally occurring asbestos from the hills of the McCullough Range overlooking Lake Mead, and including recreation areas and an elementary school. Every sample collected revealed the presence of fibrous amphibole asbestos, a form of asbestos capable of causing disease. Currently, UNLV researchers are mapping the area of asbestos found, and trying to obtain funding to collect air samples to assess the risk of exposure from different activities, including using off-road vehicles, horseback riding, or even walking in areas that contain naturally occurring asbestos.

There are fewer known locations of natural occurrences of asbestos in the New England states, but they do exist. In Massachusetts, they are mostly in the central and western parts of the state. There are also locations in Vermont. The U.S. Geologic Survey is in the process of mapping locations of historical asbestos mines, former asbestos exploration prospects, and natural asbestos occurrences. Their maps are available online at

The increase in knowledge about natural occurrences of asbestos has the potential to impact civil litigation. In asbestos cases, the investigation and identification of all sources of a plaintiff's exposure to asbestos is of paramount importance for causation assessment and determinations. It is not uncommon today for plaintiffs to seek compensation from defendants who sold one or two gaskets or brakes the plaintiffs used during their lifetime. Knowing the amount of naturally occurring asbestos in rock in areas where a plaintiff lived and worked, as well as the risk of disease posed by that, has potential to provide information about how a plaintiff came to develop asbestos-related disease.

ASTM, International (formerly American Society for Testing and Materials) has planned a symposium for researchers to present their research findings and exchange information about naturally occurring asbestos. The symposium is scheduled for April 30 to May 1, 2015. For more information, see

We follow asbestos-related developments for our clients and stay current in all areas related to that field. If you have any questions about this or other asbestos issues, please feel free to contact David Governo at [email protected], Bryna Misiura at [email protected], or Christopher van Tienhoven at [email protected].