Definitions, analytical procedures, and regulations pertaining to health risks from asbestiform minerals are as much as twenty years old. The USGS is currently re-examining the chemical and physical properties of asbestiform minerals using state-of-the-art technology that was unavailable two decades ago. Information gained from this project will be coupled with toxicological studies to enhance the current state of knowledge about asbestos and provide a foundation for reexamination of current definitions and analytical procedures. The health crisis in Libby, Montana and other locations where asbestos-bearing vermiculite ore from Libby was processed, illustrates the need for this work. From a representative suite of thirty asbestiform amphibole samples obtained from the mine at Libby, we have identified a range of amphibole compositions, most of which can be classified as winchite and richterite; some tremolite and actinolite compositions have also been identified. Because winchite and richterite are not among the six types of asbestos cited in current regulations, their potential links to the extensive health problems at Libby suggest that the definitions currently used for asbestos are in need of refinement. We are also examining the significance of terms such as “asbestos fiber” with respect to potential toxicity. Of particular concern are the distinctions commonly made in the literature between asbestos fibers and acicular cleavage fragments of the same mineral, with the cleavage fragments typically viewed as non-toxic. We are currently evaluating whether this distinction is warranted from a mineralogical, geochemical, and hence toxicological perspective.
Learning Objectives: N/A
Keywords: Asbestos, Health Risks
Presenting author's disclosure statement:
Organization/institution whose products or services will be discussed: None
I do not have any significant financial interest/arrangement or affiliation with any organization/institution whose products or services are being discussed in this session.