Asbestos-Related Radiographic Findings Among Household Contacts of Workers Exposed to Libby Vermiculite

Abstract

To explore the potential impact of worker hygiene by determining the prevalence of radiographic changes consistent with asbestos exposure among household contacts of workers exposed to Libby vermiculite that contained amphibole fibers. Workers and household contacts had chest radiographs and completed questionnaires regarding hygiene and potential exposure pathways. Participants included 191 household contacts of 118 workers. One household contact (0.5%) had localized pleural thickening, and three (1.6%) had irregular opacities at profusion category 1/0 or greater. Worker radiographs demonstrated pleural changes in 45% and irregular opacities at profusion category 1/0 or greater in 8%. Libby vermiculite-exposed workers demonstrated an elevated prevalence of pleural and interstitial chest radiographic changes. There was, however, no increased prevalence of similar changes among household contacts, likely because of personal hygiene measures taken by the majority of workers.