Most of the light, crumbly mica-like mineral vermiculite, found in the insulation of millions of homes, contains small amounts of the more dangerous mineral asbestos which has been linked to mesothelioma. Vermiculite is a harmless clay-based mineral with shiny flakes that expand when heated.  The expanded material is light-weight and fire resistant and was a popular insulator in homes, particularly between the 1920’s and the 1980’s.  It is usually found between the joists in attic floors and inside exterior walls.  While pure vermiculite is safe, vermiculite mined near Libby, Montana for more than 70 years may not be. More than 70 percent of all vermiculite sold in the U.S. before 1990, and marketed under the brand name Zonolite, was produced from the … Continue reading Vermiculite Insulation May Be Contaminated with Asbestos »