Zonolite- Serpentine or Amphibole?
Most people have heard of Asbestos and there are plenty of sites and literature on the dangers of this material.
During a home inspection I found these relics of the past. What we have here is vermiculite, specifically Zonolite which was an insulation material produced by the W.R. Grace company under the trade name of “Zonolite”.
Vermiculite is a mineral that is like mica but is a hydrated magnesium aluminum silicate mineral.
The issue with vermiculite is that it most likely was mined in Libby Montana. Pure vermiculite does not contain asbestos and is considered non-toxic. Vermiculite from the Libby mine was not always pure and may contain asbestos. Vermiculite ore that was mined in Libby, Montana was often contaminated with naturally occurring asbestos. Libby, Montana, was the source of over 70 percent of all vermiculite sold in the United States from 1919 to 1990.
From the EPA-
Gold miners discovered vermiculite in Libby in 1881. In the 1920s, the Zonolite Company formed and began mining the vermiculite. In 1963, W.R. Grace bought the Zonolite mining operations. The mine closed in 1990.
https://cumulis.epa.gov/supercpad/SiteProfiles/index.cfm?fuseaction=second.Cleanup&id=0801744
So what about asbestos? When we talk about asbestos there are two general families or classes of the ore, serpentine and amphibole.
The Serpentine asbestos fibers are long and flexible crystalline where as Amphibole asbestos are stiff, brittle, and shaped like rods or needles making this second class more problematic when it comes to being a health issue.
All asbestos can cause health issues but the Amphibole asbestos has a higher carcinogenic potential due to its biopersistence.
https://www.ncbi.nlm.nih.gov/books/NBK208394/
As home owners often you are left with, what do I do about it? If left undisturbed it not typically an issue. The problem occurs when work has to be performed and many tradespeople will want the material tested for asbestos contamination prior to working where vermiculite is present. Remediation and removal can be costly.
If you have Zonolite brand vermiculite you may be eligible for reimbursement of part of your remediation. The Trust is able to reimburse 55% of the total allowable expense. (Maximum reimbursement allowed = $4,203.37*)
See link below for information on filing a claim-
https://www.zonoliteatticinsulation.com/
More information on Vermiculite-
https://www.epa.gov/asbestos/protect-your-family-asbestos-contaminated-vermiculite-insulation
https://www.atsdr.cdc.gov/toxprofiles/tp61.pdf
If you find any errors or have additional information that would expand on any code, building standards or manufacturer requirements please let me know.
NCW Home Inspections, LLC is a Licensed Washington State Home Inspection service located in Wenatchee Washington serving Chelan County, Douglas County, Kittitas County, Okanogan County and Grant County Washington and the cities of Wenatchee, Leavenworth, Cashmere, Oroville, Cle Elum, East Wenatchee, Quincy and many more…
Your Wenatchee and Chelan Professional Real Estate, Home and Structural Pest Inspection Service
Coordinator & Instructor- Fundamentals of Home Inspection- Bellingham Technical College
Former WA Home Inspector Advisory Licensing Board
www.ncwhomeinspections.com 509-670-9572
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