Product Description

Zonolite was W.R. Grace’s brand of expanded-vermiculite insulation, sold as loose-fill pour-in-place product for residential attics, masonry-block core fills, and industrial insulation packages. Grace acquired the Zonolite Company and the Libby, Montana vermiculite mine in 1963. According to publicly filed U.S. asbestos personal-injury and wrongful-death litigation, the vermiculite ore body at Libby was contaminated with tremolite/actinolite amphibole asbestos as a naturally co-occurring mineral — a contamination pathway extensively documented in federal enforcement records, EPA site-cleanup actions, and the criminal prosecution of Grace corporate officers.

Plaintiffs alleged that Zonolite was shipped nationwide from the Libby mine to some 240 exfoliation plants, then bagged and distributed under the Zonolite name and under private-label programs from the 1960s through the mine’s 1990 closure. Distribution volume was enormous — federal estimates place Zonolite in roughly 35 million U.S. homes and countless commercial and industrial installations.

Workers Exposed

Trades and populations allegedly encountering asbestos through W.R. Grace Zonolite vermiculite insulation include:

  • Insulators (HFIAW) installing loose-fill Zonolite in attics, wall cavities, and masonry cores during original construction.
  • Construction laborers pouring and leveling Zonolite in residential and commercial applications.
  • HVAC mechanics, electricians, and telecom installers disturbing Zonolite during attic work — fiber release from any physical disturbance of the loose product.
  • Homeowners and DIY installers poured Zonolite into their own attics from retail bags — a major residential-exposure pathway.
  • Renovation and demolition workers — extraction of Zonolite during weatherization, insulation upgrades, and structural demolition released amphibole fiber.
  • Family members of Libby-mine workers and exfoliation-plant workers exposed through take-home pathways.

The Libby ore-body contamination pathway is unusual in the asbestos litigation record because it puts residential occupants, not just industrial trades, into the exposure population.