Vermiculite asbestos processed in Spokane, Washington

This health consultation evaluates the potential human health hazard posed by asbestos associated with vermiculite ore that was received from Libby, Montana, and processed at Vermiculite NW, Inc. (Vermiculite NW) in Spokane, Washington. DOH prepared this health consultation under a cooperative agreement with the Agency for Toxic Substances and Disease Registry (ATSDR).

Vermiculite is a naturally occurring, flaky material with a variety of uses, including attic insulation, soil amendments, and fire-proofing material.

Raw vermiculite contains water in its structure. When heated rapidly, the water flashes into steam, expanding the ore into accordion-like particles.

This process, called exfoliation, expansion, or “popping,” creates a lightweight material that is fire resistant, making it a useful home or building insulator.

Courtesy of the Washington Department of Health