Exposure pathway analysis of asbestos-vermiculate ore contaminants

An "exposure pathway" describes how a person comes in contact with contaminants, such as asbestos, originating from a source. Every exposure pathway consists of the following five elements:

A source of contamination;

A medium, such as air or soil, through which the contaminant can move;

A point of exposure where people can contact the contaminant;

A route of exposure by which the contaminant enters or contacts the body; and

A receptor population (people who can come into contact with the contaminant at the point of exposure).

After reviewing information from Libby, Montana, and from facilities that processed vermiculite ore from Libby, a list of possible exposure pathways for vermiculite processing facilities was developed.

All pathways have a common source (vermiculite from Libby contaminated with Libby asbestos) and a common route of exposure (inhalation).

Although asbestos ingestion and dermal exposure pathways could exist, health risks from these pathways are small in comparison to those resulting from inhalation exposure to asbestos and will not be evaluated in this health consultation.