Vermiculite is a naturally-occurring mineral that was at one time commonly used in insulation for attics and walls. Vermiculite itself is harmless. The problem is that more than 70% of all vermiculite sold in the United States from 1919 to 1940 came from a mine in Libby, Montana. The mine also held a deposit of asbestos, and so Libby vermiculite was contaminated with asbestos, the cause of mesothelioma and other diseases such as asbestosis and some forms of lung cancer.
Most of the Libby vermiculite sold in the United States was marketed under the brand name Zololite. If you have Zonolite or other vermiculite insulation in your home, you should assume that you also have asbestos in your home and take necessary precautions to protect yourself and your family from exposure.
In order to pose a risk of inhalation, asbestos fibers must become airborne. In most cases, asbestos contained in uncompromised vermiculite insulation is encapsulated and not a danger. If the insulation is disturbed or removed, however, there is a risk that asbestos fibers will be released into the air. If your attic is insulated with vermiculite, here are some tips to help you prevent or limit the potential for exposure to asbestos in your home:
- Do not disturb attic insulation.
- If you are concerned about a risk of asbestos exposure in your attic, be sure to use protective equipment. A common dust mask is not enough to prevent airborne asbestos particles from entering the lungs. A respirator, protective clothing, and protective eyewear are what OSHA recommends wearing to limit asbestos exposure.
- Use your attic as infrequently as possible. Consider storing items in another location.
- If you do cause an insulation disturbance in your attic, leave the area immediately. Take caution not to track dust from your attic into the rest of your home, where it could pose a risk to other family members.
- Do not try to remove vermiculite yourself. Hire a trained asbestos professional to test and/or remove the insulation and replace it with non-vermiculite insulation.
- Seal cracks or holes that asbestos dust from insulation could pass through (such as ceiling cracks or cracks around light fixtures or ceiling fans).
There is no safe level of exposure to asbestos. Mesothelioma, which is a deadly form of cancer caused exclusively by asbestos exposure, may not occur until decades after exposure. In most cases, vermiculite insulation can remain undisturbed and it will not release asbestos into the air. Still, it is best to exercise extreme caution if you know that areas of your home contain vermiculite insulation. For more information on vermiculite and asbestos, you can contact environmental officials in your area.