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Vermiculite was mined in Libby, Montana, from the 1920s until the mine closed in 1990. While in operation, the mine in Libby produced most of the world’s supply of vermiculite. Vermiculite has been used in building insulation, potting soil and fertilizer. Unfortunately, the vermiculite from the Libby mine contained a type of naturally-occurring asbestos called tremolite-actinolite.

How can I be exposed to asbestos in vermiculite?

Not all vermiculite contains asbestos; however, some products have been made with vermiculite containing asbestos. People can be exposed to asbestos by breathing or ingesting it. Breathing asbestos fibers poses the greatest health risk. The amount of asbestos to which a person is exposed depends on –

  • how many fibers are in the air and
  • how long the air containing asbestos fibers is breathed.

You can be exposed to asbestos by disturbing building insulation or other products with asbestos-containing vermiculite. As long as the asbestos is not released into the air, it is not harmful. If it is not being disturbed, there is very little exposure and very little danger.

What does vermiculite look like?

Pieces of vermiculite are brownish-gold and are about ½ inch in size. Pieces look like they are made of several layers.

Can I have the vermiculite in my home sampled to see if it contains asbestos?

If you want to have the vermiculite in your home sampled, we recommend that you hire a trained consultant or contractor to collect the sample and get it analyzed at a laboratory. For information about licensed contractors in Illinois, please call the Illinois Department of Public Health Asbestos Section at 217-782-5830.

We discourage collecting the sample yourself. However, if you follow the contractor’s suggestions for collecting the sample, it should not be a problem. To keep the material from getting into the air, samples should be wet when collected.

What should I do if I have insulation or other products made with vermiculite in my home?

If the vermiculite in your home contains asbestos, we recommend that you leave it in place as long as it is in a location where people are not routinely exposed to it. If it is sealed behind wallboards and floorboards or is in an attic that is not used for habitation, the best advice is to leave it in place. By not disturbing the vermiculite, you are reducing your chances for exposure to asbestos. If vermiculite is disturbed, it could cause tiny, needle-like asbestos fibers to become airborne. Asbestos in the air can be inhaled and cause lung damage. If asbestos is not in the air, it is not dangerous to your lungs. If you must remove any asbestos-containing vermiculite from your home, you should hire a licensed asbestos contractor.

Vermiculite is used in some potting soil for plant growth, and it appears as bright gold or silver flakes. Vermiculite should not be confused with the white plastic substance also found in many potting soils. Keeping your potting soil moist keeps the vermiculite moist, and lowers your chance for exposure to asbestos fibers.

How can vermiculite containing asbestos affect my health?

Most people exposed to small amounts of asbestos will not experience adverse health effects. A person must generally be exposed to asbestos for a long period of time (10 or more years) before health effects occur.

Illnesses caused by long-term asbestos exposure include –

  • asbestosis, a lung disease caused by breathing in asbestos fibers causing irritation and scarring of lung tissues
  • mesothelioma, a form of cancer in the lining of the lungs, chest, abdomen and heart caused by exposure to asbestos
  • lung cancer, tumors of the lung that are linked to asbestos exposure as well as other sources of exposure such as cigarette smoking.

Is there a medical test to show if I have been exposed to asbestos?

Asbestos fibers cannot be detected in chest X-rays, but early signs of lung disease can. Lung function tests and high resolution CAT scans can also detect changes in your lungs.

Where can I get more information?

Illinois Department of Public Health
Division of Environmental Health
Toxicology Section
525 W. Jefferson St.
Springfield, IL 62761
TTY (hearing impaired use only) 800-547-0466

U.S. Environmental Protection Agency
Superfund Hotline

Consumer Product Safety Commission

This fact sheet was supported in part by funds from the Comprehensive Environmental Response, Compensation, and Liability Act trust fund through a cooperative agreement with the Agency for Toxic Substances and Disease Registry, Public Health Service, U.S. Department of Health and Human Services.