COMMUNITY ASBESTOS EXPOSURE FROM A VERMICULITE PROCESSING FACILITY

Abstract

ISEE-424 Purpose: From the 1930s until the 1980s, vermiculite ore contaminated with amphibole asbestos was shipped from Libby, Montana to over 60 locations across the U.S. and Canada for processing into finished vermiculite products. Asbestos exposure in Libby has been associated with adverse health effects among workers and community members. The purpose of this investigation is to determine the extent to which similar exposures and health effects have occurred in a dense urban community centered on a vermiculite processing facility that received and processed Libby ore for over 50 years. Methods: In the first phase of the investigation, all individuals who lived in the study area, or reported direct contact with the processing waste from 1938 through 2001 were eligible to participate. Residential property owners were identified through city property records. Current and former residents were identified during household visits and interviews, including deceased former residents interviewed by proxy. Interviews with over 6,000 participants were conducted to characterize frequency and duration of individual exposures via ambient air, non-occupational contact with waste materials, occupational exposure and family contact with workers. Ambient air exposure was estimated using residential history in proximity to the source, and air dispersion modeling. Smoking history and occupational history with asbestos were also collected. All properties were offered a visual inspection for processing waste contamination in surface soils during household visits. Results: Processing waste was transported and used widely by the community in driveways and gardens. Playing on piles of processing waste at the facility exposed neighborhood children. Study staff and EPA inspectors discovered visible asbestos contamination on over 260 residential properties. The number and proportion of participants exposed through each exposure pathway and other descriptive characteristics of the population will be presented. Conclusion: Amphibole asbestos exposures among certain subgroups of an urban population living near a vermiculite processing facility were found to be similar to non-occupational exposures that occurred in Libby, Montana. Linkages with state and national morbidity and mortality data are planned to examine the occurrence of asbestos-related disease in the second phase of this investigation.