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Vermiculite
EPA Action in Libby, Montana
EPA Region 8 has been working closely with the Libby community to clean up contamination and reduce risks to human health.
This page contains information on asbestos contamination in vermiculite and vermiculite products, uses of vermiculite, fact sheets, question and answer documents, reports and links to EPA Regional vermiculite pages.
- Vermiculite and Its Uses
- EPA Action in Libby, MT
- Vermiculite Insulation Brochure
- Vermiculite Insulation Report
- Garden Product Report
Vermiculite and Its Uses
Vermiculite is the mineralogical name given to hydrated laminar magnesium-aluminum-iron silicate that resembles mica in appearance. All vermiculite ores contain a range of other minerals that were formed along with the vermiculite in the rock. Vermiculite ores from some sources have been found to contain asbestos minerals but asbestos is not intrinsic to vermiculite and only a few ore bodies have been found to contain more than tiny trace amounts.
Vermiculite mines are surface operations where ore is separated from other minerals, and then screened or classified into several basic particle sizes. Vermiculite is found in various parts of the world. Locations of the predominant commercial mines are in Australia, Brazil, China, Kenya, South Africa, the USA and Zimbabwe.
When subjected to heat, vermiculite has the unusual property of exfoliating or expanding into worm-like pieces (the name vermiculite is derived from the Latin 'vermiculare' - to breed worms). This characteristic of exfoliation, the basis for commercial use of the mineral, is the result of the mechanical separation of the layers by the rapid conversion of contained water to steam. During this exfoliation process, asbestos fibers can potentially be released. The increase in bulk volume of commercial grades is 8 to 12 times, but individual flakes may exfoliate as many as 30 times. There is a color change during expansion that is dependent upon the composition of the vermiculite and furnace temperature.
Vermiculite has been used in various industries for over 80 years. It is used in the construction, agricultural, horticultural and industrial markets. Examples of products that contain vermiculite include potting soil mixes, loose fill insulation, and packing material.
EPA Action in Libby, MT
EPA has been working in Libby since 1999 when an Emergency Response Team was sent to investigate local concern and news articles about asbestos-contaminated vermiculite. Since that time, EPA has been working closely with the community to clean up contamination and reduce risks to human health.
EPA Region 8 - EPA Action in Libby, MT
Vermiculite Insulation Brochure
Current Best Practices for Vermiculite Attic Insulation (PDF) (2 pp, 585K, May 2003). This publication is also available from the TSCA Hotline at 1-800-471-7127, request EPA publication number 747-F-03-001.
Current Best Practices for Vermiculite Attic Insulation (HTML)
Vermiculite Insulation Report
Summary of EPA's Pilot Study to Estimate Asbestos Exposure from Vermiculite Attic Insulation (PDF) (2 pp, 153K) - EPA completed a pilot study to evaluate the level of asbestos in vermiculite attic insulation and whether there is a risk to homeowners. The study was designed to: (1) obtain a rough estimate of the amount of asbestos in attics with vermiculite attic insulation; and (2) obtain a rough estimate of a person's exposure to asbestos while performing common household activities.
Final Draft - Pilot Study to Estimate Asbestos Exposure from Vermiculite Attic Insulation - Research Conducted in 2001 and 2002 (PDF) (55 pp, 188K). The figures and tables have been posted separately from the report in order to help reduce download time. All figures and tables are in the Adobe PDF format.
Figure 1 (1 pp, 135K) Figure 6 (1 pp, 283K) Figure 2 (1 pp, 115K) Figure 7 (1 pp, 29K) Figure 3 (1 pp, 45K) Figure 8 (1 pp, 100K) Figure 4 (1 pp, 89K) Figure 9 (1 pp, 82K) Figure 5 (1 pp, 115K) Figure 10 (1 pp, 116K)
Tables 1 and 2 (1 pp, 82K) Table 8 (1 pp, 382K) Table 3 (1 pp, 97K) Table 9 (1 pp, 14K) Table 4 (1 pp, 75K) Table 10 (1 pp, 324K) Table 5 (1 pp, 32K) Table 11 (1 pp, 176K) Table 6 (1 pp, 176K) Table 12 (1 pp, 83K) Table 7 (1 pp, 165K)
Garden Product Report
Sampling and Analysis of Consumer Garden Products That Contain Vermiculite (PDF) (205 pp, 12MB) - The Office of Pollution Prevention and Toxics (OPPT) and US EPA Region 10 (Seattle, WA) conducted independent surveys of consumer garden products containing vermiculite. OPPT and US EPA Region 10 jointly released the findings as a single report.