Asbestos-Contaminated Vermiculite

As noted previously, the vermiculite ore mined in Libby, Montana from 1920-19990 was heavily contaminated with asbestos. This contamination enacted the untimely death and diagnosis of disease of residents not only in Libby, but in the 250 U.S. cities that routinely processed the ore. Libby ore accounted for more than half the worldwide vermiculite production during the mine’s operation. Vermiculite is an established commercial commodity and is still used globally in many different applications. The mineral itself, if uncontaminated, is not known to cause any hazardous health effects.

The risk of vermiculite lies in the possible asbestos contamination, however the only method of finding this out is to have the material scientifically tested. Asbestos attorneys at Pintas & Mullins Law Firm warn the public of possible vermiculite contamination. Such corruption could lead to development of mesothelioma, asbestosis, and lung cancer.

Vermiculite is used in a wide array of industries, form horticulture to steelwork. It functions as an insulator, absorbent, fire resistor, plaster, packaging material, and growing medium. It is often used as a safe, suitable alternative to asbestos. Though mining in Libby ceased in 1990, concern is still prevalent about the harmful effects of asbestos-containing vermiculite, especially regarding the potential of contaminated material that was installed as loose-fill insulation in homes and other buildings. Much of the vermiculite from the mine near Libby was used in the manufacture of Zonolite™ Attic Insulation. However, not all Zonolite™ product was made with vermiculite from that same mine.

In general, any vermiculite that originated from the mine near Libby, Montana, should be regarded as potentially contaminated with asbestos. Bulk sampling is reliable only when over 1% of the material is asbestos. Negative results from bulk samples can therefore be falsely reassuring when less than 1% of the sample is asbestos. However, disturbing contaminated vermiculite with less than 1% asbestos can still result in hazardous concentrations of airborne asbestos fibers. NIOSH recommends workers consult Occupational Safety and Health Administration (OSHA) asbestos standards for general industry and construction when work will involve vermiculite that is known or presumed to be contaminated with asbestos.

If the vermiculite is known or presumed to be contaminated with asbestos, NIOSH recommends the following general guidelines for limiting asbestos exposure:

  • Avoid handling or disturbing loose vermiculite
  • Isolate work areas with temporary barriers or enclosures to avoid spreading fibers
  • Use wet methods, if feasible, to reduce exposure
  • Never use compressed air for cleaning
  • Avoid dry sweeping, shoveling, or other dry clean-up methods
  • Use disposable protective clothing or clothing that is left in the workplace. Do not launder work clothing with family clothing
  • Use proper respiratory protection.
  • Dispose of waste and debris contaminated with asbestos in leak-tight containers in accordance with OSHA and EPA standards.


Workers who have had significant past exposure, or have significant ongoing exposure to asbestos, to vermiculite from Libby, or to other asbestos-contaminated materials should consider getting a medical exam from a physician who knows about diseases caused by asbestos. The appendices to the OSHA asbestos standard describe the types of medical tests routinely done for workers exposed to asbestos. Workers who have been exposed and currently smoke should quit smoking. Employers can assist them by offering smoking cessation programs.

NIOSH is evaluating the potential for asbestos exposure during work with vermiculite from sources other than the mine near Libby. NIOSH is also updating a study of vermiculite workers originally conducted in the 1980s. That study found significant excesses of asbestosis and lung cancer related to contaminant fiber exposures among workers at the vermiculite operations in and around the mine near Libby.

While information continues to be gathered, precautions should be taken to minimize the generation and inhalation of dust during the handling of vermiculite known or presumed to be contaminated by asbestos. As with any dust, workers should avoid prolonged high-level exposures. Mesothelioma lawyers at Pintas & Mullins Law Firm recommend that those who suspect exposure to asbestos call immediately for a free legal consultation.

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