![[logo] US EPA](http://www.epa.gov/epafiles/images/logo_epaseal.gif){kind=logo}
IRIS Toxicological Review of Libby Amphibole Asbestos (Interagency Science Consultation Draft)
Archive disclaimer
Archived files are provided for reference purposes only. The file was current when produced, but is no longer maintained and may now be outdated. Persons with disabilities having difficulty accessing archived files may contact the NCEA Webmaster for assistance. Please visit http://epa.gov/ncea to access current information.
Contact
- Norman Birchfield
- by phone at: 703-347-0174
- by fax at: 703-347-8699
- by email at: birchfield.norman@epa.gov
- by fax at: 703-347-8699
Downloads/Related Links
- IRIS Toxicological Review of Libby Amphibole Asbestos (Interagency Science Consultation Draft) (PDF) (483 pp, 5 MB, about PDF)
- Charge to External Peer Reviewers (PDF) (5 pp, 90 KB, about PDF)
- EPA's Response and Comments from the Interagency Science Consultation Meeting (PDF) (93 pp, 2 MB, about PDF)
Related Link(s)
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).
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).
History/Chronology
| 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 External Review Draft for public review and comment, and announced the public listening session would be held on October 6, 2011. [Federal Register Notice Aug 25, 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 (Interagency Science Consultation Draft). U.S. Environmental Protection Agency, Washington, DC, EPA/635/R-11/002C, 2011.