Vermiculite insulation, has been used as loose-fill wall cavity and attic insulation in North America since the early 1920s. Pure Vermiculite does not pose any known health risks, however Vermiculite mined from the popular Libby, Montana site has been identified as containing traces of Tremolite asbestos. For the home owner with Vermiculite insulation, the origin of the naturally occurring mineral is of the most concern, however for the average home buyer, the stigma attached to the presence of Vermiculite affects the entire real estate transaction.
Health Risks for the Homeowner
The health risks associated with owning and occupying a property with loose-fill Vermiculite insulation is generally regarded as low, due to the limited direct exposure a home owner has to the installed insulation. Approximately 60% of Vermiculite insulation installed in North America is Asbestos Containing Material (ACM) due to the popularity and market dominance of some domestic insulation suppliers up to the early 1990's. While it is not guaranteed to contain asbestos, without testing to determine Vermiculite composition, the Canadian Centre for Occupational Health and Safety notes that "it is reasonable to assume that it may be contaminated with asbestos." The known risks associated with exposure to asbestos containing Vermiculite include; Asbestosis, Mesothelioma and Lung Cancer. Risk is increased with exposure, therefore the following precautions should be taken to prevent the disruption of Vermiculite insulation which can cause asbestos fibres to become airborne:
- Seal all cracks and gaps in ceilings to prevent air-changes between air space and living space.
- Do not store items in the attic.
- Minimize the opening of attic hatches.
- Do not remove the insulation yourself.
- Inform all contractors that Vermiculite insulation that may contain asbestos is present and only hire contractors licensed to handle and deal with asbestos.
Vermiculite and Real Estate Transactions
The reality of owning or buying a property that contains Vermiculite is that there is risk associated with exposure to asbestos containing material and a financial liability assumed with affected property ownership. It is imperative that Vermiculite is tested to determine if it contains asbestos; there is a 60% chance that it is asbestos containing material (ACM), and there are legal requirements in some jurisdictions to verify if asbestos is present in order to notify contractors of potential risk. Costs associated with Vermiculite analysis vary with geographic location, however it is important to note the following:
- Sample collection and sample integrity is a critical issue regarding validity of results. Testing methodology dictate specific steps be taken in order to collect a representative sample of homogeneous material: do not trust testing accuracy to home inspectors or your best effort. Poor sampling methods equal inaccurate and invalid results. There is significant liability for the selling (or renovating) homeowner attached to providing invalid negative results that effect the end-user or contractor. Hire a testing professional.
- Due to the physical structure of asbestos fibres and Vermiculite, distribution of asbestos within Vermiculite is inconsistent and fibres settle over time. Accurate testing requires the collection of mulitple samples from multiple locations within the installed insulation.Vermiculite is often a sales negotiating point. Potential buyers of properties that contain Vermiculite expect a selling price discount associated with the potential expense associated with removing asbestos containing Vermiculite. Having a professional collect viable samples with analysis performed at an accredited testing laboratory will arm the seller with the information required to determine if an abatement performed before listing is advantageous or required at all.