The International Agency for Research on Cancer (IARC) has classified some forms of fibrous zeolites, such as erionite, as carcinogenic to humans. Erionite fibers, which are similar in shape and size to asbestos fibers, have been linked to high rates of mesothelioma in specific geographic regions where exposure is prevalent. However, not all zeolites pose the same risk, and non-fibrous zeolites are generally considered safe.
