Bulletin 245: Vermiculite insulation - asbestos contamination

​​​Concerns have been raised about the potential health risk posed by vermiculite sold as Zonolite Attic Insulation and possibly other brands sold in Canada. The vermiculite ore, mined at the Libby Mine in Montana (prior to its closure in 1990), may contain small amounts of asbestos contamination. Under the Workplace Safety and Health Regulation, the definition of asbestos-containing material includes vermiculite and any asbestos found or observed in a sample.