Erionite in the United States? Who Knew. Public Health Implications and Ongoing Activities

Background: Exposure to erionite, an asbestos-like mineral, causes unprecedented rates of malignant mesothelioma (MM) mortality in several Turkish villages. Erionite deposits are also present in at least 12 US states, and erionite-containing gravel has been used on hundreds of miles of road in ND. We investigated exposures associated with erionite-containing gravels in Dunn County, ND, compared to erionite exposures in Turkish villages with MM. Additionally, a pilot radiographic study of exposed workers in ND was performed to assess the risk of erionite-associated lung abnormalities. Methods: We evaluated erionite samples and airborne point exposure concentrations in ND and in Turkish villages with elevated rates of MM. In ND, 34 participants completed a questionnaire, chest radiograph, and HRCT scan to assess the prevalence of lung changes consistent with fibrous mineral exposure. Results: Airborne erionite concentrations were measured in ND along roadsides, indoors, and inside vehicles, including school buses. While generally lower than Turkish villages, roadside samples could exceed concentrations in Boyali (6.25% MM death rate). The physical and chemical properties of ND and Turkish erionite were very similar. Radiographic changes were observed by HRCT in seven (21%) of the participants. Three participants (8.8%) with extensive occupational gravel exposures demonstrated bilateral localized pleural changes with calcification; two also had accompanying interstitial changes. Conclusions: Public health officials and physicians in areas with erionite contaminated gravels should be aware of the potential health effects of erionite exposure. Precautionary measures should be taken to limit community use and occupational exposure to gravel containing erionite.