IRIS Toxicological Review of Libby Amphibole Asbestos (External Review Draft)
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EPA is conducting a peer review of the scientific basis supporting the human health hazard and dose-response assessment of Libby Amphibole Asbestos that will appear in the Integrated Risk Information System (IRIS) database. Please refer to IRISTrack - Libby Amphibole Asbestos for the latest schedule updates.
Libby Amphibole asbestos is a complex mixture of amphibole fibers, both mineralogically and morphologically. The mixture primarily includes tremolite, winchite, and richterite fibers with trace amounts of magnesioriebeckite, edenite, and magnesio-arfvedsonite. These fibers exhibit a range of morphologies (e.g. prismatic, ascicular, asbestiform)(Meeker et al., 2003).
Exposure to Libby Amphibole asbestos results in the same types of adverse health effects as are seen with exposure to other amphibole mineral fibers. Epidemiologic studies of workers exposed to Libby Amphibole asbestos fibers indicate increased mortality from lung cancer, mesothelioma, asbestosis, and other nonmalignant respiratory diseases (McDonald et al., 1986a, 2004; Amandus and Wheeler, 1987; Amandus et al., 1987a; Sullivan, 2007; Larson et al., 2010a, Moolgavkar et al., 2010). Morbidity studies report increased asbestosis, pleural thickening and decreased lung function in exposed individuals (Weill et al., 2010; Larson et al., 1020b; Rohs et al., 2008, Peipens et al., 2003, ATSDR, 2001; Amandus et al., 1987b and McDonald et al., 1986 b.)
|Aug 2007||The Libby Amphibole Asbestos assessment was initiated in 2007. It was nominated for assessment by the IRIS Program because it supports OSWER and Region 8 site clean-up and related risk management initiatives at this Superfund site. An assessment for Libby Amphibole Asbestos is not currently on IRIS.|
|May 2011||EPA hosted an interagency science consultation on the draft IRIS Toxicological Review of Libby Amphibole Asbestos.|
|Aug 2011||EPA released the draft IRIS Toxicological Review of Libby Amphibole Asbestos for public review and comment, and announced the public listening session. [Federal Register Notice Aug 25, 2011]|
|Dec 2011||EPA's Science Advisory Board (SAB) announced a public peer review meeting on the draft IRIS Toxicological Review of Libby Amphibole Asbestos that was held on Feb 6 -8, 2012 in Alexandria, VA. [Federal Register Notice Dec 23, 2011]|
|Jan 2013||EPA's SAB released the final report from the "Review of EPA’s Draft Assessment Entitled Toxicological Review of Libby Amphibole Asbestos (August 2011)"|
This download(s) is distributed solely for the purpose of pre-dissemination peer review under applicable information quality guidelines. It has not been formally disseminated by EPA. It does not represent and should not be construed to represent any Agency determination or policy.