Research Plan for Dosimetric and Toxicologic Assessment of Amphibole Asbestos Fiber-Containing Materials From Libby, MI

Riepilogo

This action announces a plan for a series of research projects aimed at addressing the toxicological effects and dosimetry of amphibole asbestos-contaminated vermiculite from Libby, Montana (referred to here as Libby amphibole). Although available human data establish the toxicity of asbestos, and preliminary dose response analyses for Libby amphibole have been developed, these estimates can be refined by addressing some of the key uncertainties that exist due to gaps in our understanding or lack of quantitative descriptions of internal dosimetry and toxicological effects. This planned set of projects is aimed at addressing these gaps and providing tools for quantitative characterization, including a comparative analysis of the toxicity of Libby amphibole relative to asbestos fibers and asbestos- like mineral occurrences. Other key areas of research will also inform the risk assessment, including inherent toxicity of Libby amphibole relative to other forms of asbestos and differential susceptibility, including that of different life stages. EPA conducted an internal and external review of the research plan and has documented the responses to comments.