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Vermiculite is a nonfibrous silicate mineral with multiple consumer uses that has been shown to contain various concentrations of asbestiform fibers. ermiculite is a micaceous hydrate of magnesium-iron-aluminum silicates with the ability to exfoliate or expand up to 20 times its original size at high temperatures. t has high-cation-exchange capacity and a very low thermal conductivity. ost of the vermiculite mined and beneficiated is exfoliated and used in construction aggregates, insulation, andagricultural applications. xposure to vermiculite occurs mainly via the inhalation route. onoccupational exposure to vermiculite is high. n 1979, approximately 13 million persons were estimated to have been exposed to vermiculite. Genotoxicity and cytotoxicity studies were not found in the available literature. imilarly, teratogenicity and reproductive effects studies were not found. The weight of evidence from data for human health effects and animal toxicity are Inadequate to characterize the carcinogenic potential of vermiculite. he carcinogenicity classification for vermiculite is D. owever, the weight of evidence for asbestos-contaminated vermiculite is sufficient to show a causal relationship for increased lung cancer in miners and millers. imilarly, human health effects and animal toxicity data are inadequate to characterize noncarcinogenic effects associated with vermiculite exposure.


U.S. EPA. HEALTH ASSESSMENT DOCUMENT FOR VERMICULITE. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/8-91/037 (NTIS PB92166834), 1991.

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Project Officer: ennis Kotchmar