Research | Children’s Health Exposure to Asbestos-Containing Vermiculite Ore and Respiratory Symptoms among Individuals Who Were Children While the Mine Was Active in Libby, Montana Lisa C. Vinikoor,1 Theodore C. Larson,2 Thomas F. Bateson,3 and Linda Birnbaum4 1U.S. Environmental Protection Agency, Research Triangle Park, North Carolina, USA; 2Agency for Toxic Substances and Disease Registry, Atlanta, Georgia, USA; 3U.S. Environmental Protection Agency, Washington, DC, USA; 4National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, North Carolina, USA Background : Libby, Montana, was home to the largest vermiculite ore mine in the United States. The processing, use, and transport of the ore, which was contaminated with amphibole asbestos, led to generalized contamination of the community. The mine closed in 1990. o Bjectivs : We examined the prevalence of respiratory symptoms in 2000–2001 and their associa- tion with history of vermiculite exposure among people who were ≤ 18 years of age when the mine closed. Methods : Information on respiratory symptoms and exposure history was collected by question- naire in 2000–2001, at which time participants were 10–29 years old. Logistic regression was used to model the associations between exposures and outcomes adjusted for age, sex, and tobacco smoke exposure. r esult : Of the 1,003 individuals included in the study, 10.8% reported usually having a cough, 14.5% reported experiencing shortness of breath when walking up a slight hill or hurrying on level ground, and 5.9% reported having coughed up bloody phlegm in the past year. These respiratory symptoms were positively associated with frequently handling vermiculite insulation compared with never handling vermiculite insulation. We found no association between vermiculite insulation in the house and respiratory symptoms. Respiratory symptoms were associated with other vermiculite expo- sures as well, and the number and frequency of these activities showed a positive trend with usually having a cough. We found no association between any of the activities and abnormal spirometry. c onclusi : These data suggest that residents of Libby, Montana, who were children when the mine closed experienced some respiratory symptoms associated with asbestos-contaminated ver- miculite exposure. k ey words : asbestos, children, Libby, Montana, respiratory symptoms, spirometry, vermiculite ore. Environ Health Perspect 118:1033–1038 (2010). doi:10.1289/ehp.0901680 [Online 23 March 2010] Libby is a small community located in the Kootenai River Valley of northwestern Montana approximately 6 miles southwest of Zonolite Mountain, a mountain containing high concentrations of vermiculite ore. The ore was mined beginning in the 1920s by the Zonolite Company and then later by W.R. Grace, which bought the mine in 1963. It is estimated that between 1924 and 1990, when the mine was closed, a total of 5.8 million tons of vermiculite ore was mined and dis- tributed (Kuntz et al. 2009), making Zonolite Mountain the largest vermiculite ore mine in the United States. In addition to the mine, processing, exfoliation, and shipping prepara- tions were performed in Libby. The ore was then used in many products ranging from insulation to soil additives and fertilizers. The vermiculite ore contained amphibole asbestos. Libby amphibole asbestos was deter- mined to be composed of tremolite, winchite, and richterite (Meeker et al. 2003). The International Agency for Research on Cancer recently concluded that “all forms of asbestos are ‘carcinogenic to humans’” and that “min- eral substances (e.g., talc or vermiculite) that contain asbestos should also be regarded as ‘carcinogenic to humans’” (Straif et al. 2009). As with other forms of asbestos, exposure to Libby amphibole asbestos has been shown to negatively affect human health. Occupational studies have shown increased morbidity and mortality (specifically from respiratory can- cers and other respiratory diseases, including asbestosis) associated with exposure to the asbestos-contaminated vermiculite from Libby (Amandus and Wheeler 1987; Amandus et al. 1987; McDonald et al. 1986, 2004; Sullivan 2007). Studies have also shown increased morbidity and mortality among individuals living in Libby, Montana, who did not work at the mine [Agency for Toxic Substances and Disease Registry (ATSDR) 2000, 2002; Muravov et al. 2005; Noonan et al. 2006; Peipins et al. 2003; Whitehouse et al. 2008]. Health effects continue to be seen in for- mer workers and community members. In 2000–2001 the ATSDR began a screening program for individuals living and/or work- ing in Libby. Using these data researchers have found positive associations between asbestos-contaminated vermiculite exposure and pleural abnormalities seen by radiograph (Peipins et al. 2003) and self-reported history of systemic autoimmune diseases (Noonan et al. 2006). Despite the mine’s closure, there Environmental Health Perspectives • volume 118 | number 7 | July 2010 is concern about the long-term effects of the mining operation for both those exposed in childhood and those exposed to lingering environmental contamination. This age group is of particular importance because lung development continues through adolescence until about 18 years of age in girls and the early 20s in boys. Previous research has shown reduced lung development in children 10–18 years of age who were exposed to ambient air pollution (Bateson and Schwartz 2008; Gauderman et al. 2004). Using the avail- able ATSDR survey data, we examined the prevalence of respiratory symptoms and their association with vermiculite exposure among individuals who were no older than 18 years of age while the mine was in operation and who were continually exposed through linger- ing environmental contamination. This has not been addressed by previous research. Materials and Methods In 2000 and 2001, ATSDR conducted a study of individuals who resided, worked, attended school, or participated in other activities in the Libby area for at least 6 months before 31 December 1990. In-person interviews and medical tests were performed in 2000 (July–November) and 2001 (July–September). Trained interviewers administered a computer-assisted question- naire to obtain information on demographics, residential history, household contact with a W.R. Grace employee, occupational his- tory, recreational activity history, history of other potential vermiculite exposures, indi- vidual and household members’ smoking status/history, medical history, and current symptoms/illnesses. Parents completed proxy interviews for children < 18 years of age. In Address correspondence to L.C. Vinikoor, U.S. Environmental Protection Agency, MD B243-01, 109 T.W. Alexander Dr., Research Triangle Park, NC 27711 USA. Telephone: (919) 541-2931. Fax: (919) 541-4284. E-mail: vinikoor.lisa@epa.gov The views expressed in this article are those of the authors and do not necessarily reflect the views or policies of the U.S. Environmental Protection Agency, Agency for Toxic Substances and Disease Registry, or National Institute of Environmental Health Sciences. The authors declare they have no actual or potential competing financial interests. Received 10 November 2009; accepted 12 March 2010. 1033