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Libby Amphibole Asbestos Outdoor Air Concentrations - Then and Now iber/cc) ... Title: Libby Asbestos Superfund Site Draft Site-wide Cumulative Human Health Risk Assessment (HHRA) Public Meeting Presentation given by Dr. Deborah McKean Author: NONE, / EPA Subject: Region ID: 08 DocID: 1272475; DocDate: 12-08-2014
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At peak output, the WR Grace vermiculite mine located in Libby was producing 80% of the world's vermiculite. Vermiculite contaminated with Libby Amphibole asbestos was shipped to nearly …
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The raw Libby ore was estimated to be 21–26% asbestos by weight; the mill feed was 3.5–6.4% asbestos; airborne dust in the dry mill was 40% asbestos ; and the vermiculite concentrate shipped to numerous processing plants in the United States and other countries was 0.3–7.0% asbestos before expansion (Amandus et al. 1987; Atkinson et al ...
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This page contains other documents related to the IRIS assessment of Libby Amphibole asbestos.
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assessment of Libby Amphibole Asbestos (dated August 2014) Date: August 13, 2014 ... reference concentration (RfC), including the choice of principal study and critical effect (localized pleural thickening), and use of uncertainty factors, seems appropriate. Likewise, the derivation of the inhalation unit risk
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The vermiculite mine near Libby began limited operations in the 1920s and was operated on a larger scale by the W.R. Grace Company (Grace) from approximately 1963 to 1990. Vermiculite from the mine contains varying concentrations of amphibole asbestos, referred to as "Libby amphibole asbestos" or LA.
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Libby asbestos (LA) is a form of amphibole asbestos unique to the Libby vermiculite deposit and is fundamentally different from more commonly found chrysotile asbestos. Chrysotile asbestos was used in commercial products for decades and is ... concentration of LA within them, but also the likelihood that these source materials may be disturbed.
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• Sources of the LA fibers found in outdoor ambient air in Libby could not be identified with certainty, but windborne transport of fibers present in soils and dust around the community …
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Download Table | Concentration of Asbestos in Air Associated with Disturbance of Vermiculite from publication: SUBJECT: Amphibole Mineral Fibers in Source Materials in Residential and Commercial ...
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Primary and secondary literature sources were screened for information on ambient concentrations of airborne asbestos in outdoor air and in buildings in the United States. The …
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Exposure Information Human exposure to Libby Amphibole asbestos is observed in the Libby, Montana region, at sites where the LAA contaminated vermiculite was processed, and at locations where it was used, including homes with insulation derived from Libby vermiculite. ... Montana region were exposed to high ambient air concentrations of LAA ...
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Background: Human exposure to Libby amphibole (LA) asbestos increases risk of lung cancer, mesothelioma, and ... injury, and cell proliferation. Short-term results guided concentration levels for a stop-exposure study in which rats were exposed to …
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Asbestos in Libby, Montana, and Related Actions to Address Asbestos- Contaminated Materials GAO-03-469. EPA has had a long track record investigating and cleaning up asbestos contamination at Libby, Montana. As far back as 1982, EPA reported that ... high concentrations of asbestos, which, when released into the air, can ...
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Background Vermiculite from the mine near Libby, Montana, is contaminated with tremolite asbestos and other amphibole fibers (winchite and richterite). Asbestos-contaminated Libby vermiculite was used in loose-fill attic insulation that remains in millions of homes in the United States, Canada, and other countries. Objective This report describes asbestos-related …
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Problem Libby Montana Asbestos Mill. Given: Stack height = 61 meters Pollutant emission rate = 52.5 grams/sec. Stack inside diameter = 1.5 meters Stack gas exit velocity = 12.92 meters/sec Stack gas exit temperature = 400 degrees K Ambient air temp = 293 degrees K Rural option Receptor height = 0 Assume the asbestos particles are small and behave as a gaseous …
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It was realized that the vermiculite ore bodies from the mine site called "Zonolite Mountain" contained amphibole asbestos at concentrations ranging up to nearly in selected areas. Thus virtually all vermiculite from Zonolite Mountain was contaminated with the most toxic form of asbestos called Libby amphibole asbestos.
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The following sections summarize available data on the range of concentration values of Libby-type asbestos in samples of potential source materials (e.g., yard soil, garden soil, waste piles, driveway material, indoor dust, vermiculite insulation, etc.) at numerous locations in residential
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Characterization tests conducted using Libby Amphibole 2007 (LA 2007) demonstrated the prototype system delivered stable and controllable aerosol concentration to the exposure carousel.
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These efforts have achieved significant reductions in air concentrations of asbestos fibers in Libby. Those levels are 10,000 times lower since the company left the community. The Libby Asbestos site includes portions of the towns of Libby and Troy and an inactive vermiculite mine seven miles northeast of the town of Libby. Vermiculite had been ...
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Download Table | Concentration of Asbestos in Air Associated with Activities from publication: SUBJECT: Amphibole Mineral Fibers in Source Materials in Residential and Commercial Areas ...
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The total concentration of asbestos fibers detected in duplicate samples taken during disturbance of Soil 12 was 1.526 f/cc and 2.186 f/cc. Analysis of air samples taken during disturbance of Soils 5, 6, 7, and 11 revealed lower numbers of asbestos fibers. Total concentration of asbestos fibers detected in duplicate samples taken during ...
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Specifically, Libby amphibole (LA) asbestos 2007 (referred to as LA 2007, bulk materials) (Lowers et al. Citation 2012), a test material representing the air from the vermiculite mine near Libby, Montana (MT) was selected as a model fiber, with the generation of in vivo data complementing robust chemical/physical characterization and human ...
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CLINICAL IMPLICATIONS: EPA has established a new reference concentration of asbestos specific to Libby which is significantly lower than other asbestos reference concentrations verifying the toxicity of the Libby fibers. Asbestos will remain after clean-up is complete, and local institutional controls to mitigate ongoing exposures are still being developed.
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Basis: Under the EPA Guidelines for Carcinogen Risk Assessment (U.S. EPA, 2005a), Libby Amphibole asbestos (LAA) is "carcinogenic to humans" following inhalation exposure based on epidemiologic evidence that shows a convincing association between exposure to LAA fibers and increased lung cancer and mesothelioma mortality.
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FINAL i TABLE OF CONTENTS 1.0 INTRODUCTION .............................................................................................................. 1 2.0 STUDY ...
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Libby Amphibole asbestos was transported across the nation to nearly 300 processing facilities. Vermiculite products were used in many public places such as parks, schools, sports fields, tracks, lawns and gardens. Occupational Exposure. Cleaning locations insulated with vermiculite;
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concentrations of asbestos—was mined at Libby between 1923 and 1990, and accounted for most of the world's vermiculite. Mining, processing, or any disturbance of the contaminated vermiculite releases asbestos fibers into the air, which can lead to respiratory illnesses, including asbestosis. When processed, the vermiculite is
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The Libby Asbestos Superfund Site is located in northwestern Montana near the town of Libby. The Zonolite Company began mining vermiculite at the site in the 1920s and the mine was purchased by W.R. Grace in 1963. W.R. Grace operated the mine until its closure in 1990. During operation, the mine produced approximately 80% of the world's ...
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Libby, Montana, is a community that has been impacted by past and potentially on-going releases of asbestos into air from waste materials associated with historic mining activities at a nearby vermiculite mine. However, it is important to understand that ... 2.0 Strategy for Locating Information on Airborne Concentrations of Asbestos
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The EPA evaluated more than 150 different activities and collected more than 5000 activity-based air samples throughout Libby to understand what the asbestos exposures could be. Top soil with an asbestos concentration of 1% or greater was removed down to a level of 1 m; soil with concentrations as low as 0·2% was removed to a depth of 0·5 m.
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