Vermiculite insulation in 35M+ homes may contain Libby asbestos

The W.R. Grace mine near Libby, Montana supplied over 70% of all vermiculite sold in the United States from 1919 to 1990, and this vermiculite was contaminated with tremolite-actinolite asbestos (now called Libby Amphibole). It was sold under the brand name Zonolite and poured into attic spaces of millions of American homes. The EPA's official guidance states homeowners should assume any vermiculite insulation may be contaminated -- yet most homeowners have no idea what vermiculite looks like (gray-brown pebble-like granules) or that it exists in their attic. So what? When homeowners enter their attic to store boxes, install lighting, run network cables, or add blown-in insulation on top, they disturb the vermiculite and inhale Libby Amphibole fibers. So what? Unlike chrysotile, amphibole asbestos fibers are needle-shaped and far more carcinogenic, with even brief exposures linked to mesothelioma. The reason this persists: there is no national registry of Zonolite-insulated homes, the product was installed by previous owners decades ago with no documentation, visual identification is unreliable without lab testing, and the EPA has no program to proactively notify current homeowners. The Libby Superfund site cleanup alone has cost over $600 million, but the millions of downstream homes remain unaddressed.