What is vermiculite insulation?
Vermiculite is a naturally occurring mineral ore that is sometimes contaminated with naturally occurring asbestos. Vermiculite has the unusual property of expanding into worm-like accordion shaped pieces when heated.
The expanded vermiculite is a light-weight, fireproof, absorbent, and odorless material.
These properties allow vermiculite to be used to make numerous products, including attic insulation.
Courtesy of The EPA
Information on horticultural products with asbestos vermiculite