Exposure to asbestos-contaminated vermiculite poses significant health risks, primarily through the inhalation of asbestos fibers. These fibers can cause a range of severe diseases, including asbestosis, lung cancer, and mesothelioma. The risk of developing these conditions generally increases with the intensity and duration of exposure. Symptoms of these diseases may not appear for 15 to 40 years after the initial exposure. [2] [4]

To protect workers from asbestos-contaminated vermiculite, NIOSH recommends several guidelines:

• Avoid handling or disturbing loose vermiculite.
• Isolate work areas with temporary barriers or enclosures.
• Use wet methods to reduce exposure.
• Never use compressed air for cleaning.
• Avoid dry sweeping, shoveling, or other dry clean-up methods.
• Use disposable protective clothing and proper respiratory protection.
• Dispose of contaminated waste in leak-tight containers. [1]

When working with vermiculite presumed to contain asbestos, respirators equipped with high-efficiency (N100) filters or supplied air respirators should be used to reduce asbestos exposure below the OSHA limits. Medical clearance and respirator training are also required. Disposable respirators or dust masks are not appropriate for avoiding asbestos exposure. [1]

The permissible exposure limit (PEL) for asbestos is 0.1 fibers per cubic centimeter of air (0.1 f/cc) averaged over the 8-hour workday, and 1 fiber per cubic centimeter of air (1.0 f/cc) averaged over a 30-minute work period. [5] [6]

Any vermiculite that originated from the mine near Libby, Montana, should be regarded as potentially contaminated with asbestos. [2]

If you suspect that your home may contain vermiculite insulation, it is recommended to have the insulation tested before doing any work as it may contain asbestos. [3]

The best way to minimize asbestos exposure from vermiculite is to NOT remove or disturb the insulation. Moving the vermiculite will cause fibres to become airborne. [3]