Click the following link to view the PDF of this paper: Loose-Fill Vermiculite, Asbestos Surveys, and Incidental Disturbances

Joseph D. Grabowski
Asbestos Services Manager
Atlantic Testing Laboratories

Vermiculite was used throughout the 20th century in construction materials, including as loose-fill insulation for commercial buildings and residential homes. It was also commonly used as a potting soil additive. Vermiculite is not an asbestos mineral, but when mined in places like Libby, Montana, it became contaminated with tremolite asbestos deposits located within the vermiculite mines. As a result, loose-fill vermiculite, known commercially as Zonolite, is considered a Presumed Asbestos-Containing Material in the State of New York.

Vermiculite used in wall cavity (above) and floor (below)

When loose-fill vermiculite is installed, asbestos fibers settle toward the bottom over time due to gravity. If a sample of settled material was analyzed, it would not be representative of the asbestos content of the loose-fill vermiculite. Therefore, there is no approved laboratory analysis method for loose-fill vermiculite in New York State. For that reason, if loose-fill vermiculite is encountered during an asbestos survey in New York State, it must be quantified and assumed to contain asbestos.

Loose-fill vermiculite is typically found in attics and wall cavities where it was placed as insulation. Walls constructed with concrete masonry units (CMU) were commonly insulated with loose-fill vermiculite. Because CMU wall cavities are not typically exposed to view during an asbestos survey, caution should be exercised when impacting these walls during renovation/ demolition projects. It is recommended to confirm that loose-fill vermiculite does not exist in CMU wall cavities prior to impacting these walls. If a CMU wall is impacted, and loose-fill vermiculite is released, the area should be evacuated immediately, and an Incidental Disturbance Assessment performed to determine the extent of contamination.

Atlantic Testing Laboratories, a WBE Certified Company, provides Asbestos Inspection, Incidental Disturbance Assessment, Asbestos Abatement Design, and Asbestos Abatement Project Monitoring Services throughout New York State.

For more information, contact Joseph Grabowski at 315-386-4578,, or visit


  • Asbestos Surveys, Design, and Project Monitoring
  • Lead Surveys, Design, and Project Monitoring
  • PCB Surveys, Design, and Project Monitoring
  • Mold Surveys, Design, and Project Monitoring
  • Building Surveys, Design, and Project Monitoring