EPA: "Most Significant Sources of Libby Amphibole Asbestos Have Been Removed"

Published December 10, 2014

EPA has announced that its cleanups of Libby and Troy—two towns in Montana that had significant and uncontrolled sources of Libby amphibole asbestos (LAA) due to the mining and processing of contaminated vermiculite—have been effective in reducing cancer and non-cancer risks in both towns. According to the agency, the major sources of LAA in and around Libby and Troy have been removed, including more than one million cubic yards of impacted soil. EPA’s outdoor air testing for LAA in Libby and Troy indicates that asbestos air concentrations are now equivalent to those found in other Montana cities. The agency notes that air asbestos concentrations today are approximately 100,000 times lower than when the mine and processing facilities were in operation. EPA released this and more information on Monday as part of its final Integrated Risk Information System (IRIS) health assessment for LAA and draft human health risk assessment for the Libby Superfund site.

EPA’s IRIS health assessment for LAA finds that it is carcinogenic to humans when inhaled and provides a quantitative estimate of cancer risk. The IRIS assessment also includes analysis of the potential cancer and non-cancer human health effects from inhalation exposure to LAA and the final toxicological review of LAA. EPA has also estimated the amount of LAA that a person can breathe every day for a lifetime that is likely to not result in adverse non-cancer health effects—the first such estimate regarding non-cancer effects for any type of asbestos.

According to the agency’s press release, EPA has been working in Libby since 1999. The site was placed on the Superfund National Priorities List in 2002, and in 2009, EPA and the U.S. Department of Health and Human Services announced a public health emergency at the Libby site.

IRIS is a human health assessment program that evaluates information on health effects that may result from exposure to environmental contaminants. EPA’s IRIS database contains more than 550 chemical substances along with information regarding their impact on human health.

EPA’s new documents related to LAA are available via the agency website.