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IRIS Toxicological Review of Libby Amphibole Asbestos (External Review Draft)

Contact
Thomas F. Bateson
by phone at:   703-347-8570
by email at:  bateson.thomas@epa.gov

Notice

EPA announced the release of the IRIS Toxicological Review of Libby Amphibole Asbestos (External Review Draft) for public viewing and comment. Public comments received on the Toxicological Review within 60 days after the release of the FRN will be considered by EPA in the development of the final Toxicological Review. Additionally, these public comments will be made available to the external peer review panel. [Federal Register Notice Aug 25, 2011] In December 2011, EPA's Science Advisory Board 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]. In March 2012, the SAB announced two public teleconferences of the SAB Libby Amphibole Asbestos Panel to discuss the Panel's draft review report of EPA's Toxicological Review of Libby Amphibole Asbestos (August 2011 Draft) on May 1 and May 8, 2012. [Federal Register Notice March 28, 2012]

Update: EPA has replaced the draft report (main) on Feb 14 with a copy with included links to the reports citation's available as a reference from the HERO (http://epa.gov/hero) Database.

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.

Downloads/Related Links

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.

Related Link(s)

Public Comments

Comments on the assessment may be submitted and reviewed using the e-Government Regulations.gov Web site. From the site, select “Environmental Protection Agency” and the keyword “EPA-HQ-ORD-2011-0425 (for the docket ID) to comment on this report.

Background
This draft health assessment of the toxicity of Libby amphibole asbestos was prepared by staff in both EPA’s Region 8 Office and ORD/NCEA. The assessment is focused on a specific type of asbestos found as a consequence of the mining and processing of vermiculite in Libby, Montana. The assessment will be included on EPA's IRIS data base when finalized. The project supports OSWER and Region 8 site clean-up and related risk management initiatives at the Libby Superfund site. As with all IRIS assessments, the development of this external peer review draft document required internal EPA review and OMB/interagency review. After an independent external peer review, the draft final document will undergo a second round of EPA and OMB/interagency review before being finalized and then included on the IRIS data base.

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.)

History/Chronology

Aug 2007The 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 2011EPA hosted an interagency science consultation on the draft IRIS Toxicological Review of Libby Amphibole Asbestos.
Aug 2011EPA 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 2011EPA'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 2013EPA's SAB released the final report from the "Review of EPA’s Draft Assessment Entitled Toxicological Review of Libby Amphibole Asbestos (August 2011)"

Next Steps

Following external peer review, the assessment will be revised taking into consideration external peer review and public comments. It will then be revised as appropriate and will undergo a final EPA internal review and a science discussion with other federal agencies and White House offices, and will be posted to the IRIS database. This Assessment does not replace the existing IRIS listing for asbestos (EPA, 1988).

Citation

U.S. EPA. IRIS Toxicological Review of Libby Amphibole Asbestos (External Review Draft). U.S. Environmental Protection Agency, Washington, DC, EPA/635/R-11/002A, 2011.

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