LIBBY ASBESTOS SITE
LIBBY, LINCOLN COUNTY, MONTANA
CONCLUSION
For the 20-year period reviewed in this report, mortality in Libby resulting from
asbestosis was approximately 40 to 60 times higher than expected. Mesothelioma
mortality was also elevated over this period, but since statistics on this extremely rare
cancer are not routinely collected, it was difficult to precisely evaluate the degree to
which mesothelioma mortality was elevated. Even though these two underlying causes of
death are elevated in the Libby study population, they still may be underestimated when
evaluated solely through the use of death certificate data.
These findings supports the community's and the media's perception that Libby residents
have been adversely impacted by historical asbestos exposure. Other underlying causes
of mortality including lung cancer, digestive cancer, and diseases of pulmonary
circulation were not significantly elevated over this period. There were no significantly
increasing trends in mortality due to all of the underlying causes analyzed.
RECOMMENDATIONS
Generate dose estimates for air dispersion of asbestos to characterize community exposure in Libby.
Collect occupational, residential, and health behavior information on decedents in the 20-year study population.
Confirm asbestosis cases through a review of medical records.
Link mortality data with the case series being developed by ATSDR's Division of Health Studies.
Conduct morbidity and mortality studies of workers and community members near exfoliation facilities that received contaminated vermiculite ore from the Libby mine.
Update the occupational population begun by the National Institute for Occupational and Safety Health or McGill University.
Develop and maintain a national registry for malignant mesothelioma.
Acknowledgements:
Bruce Schwartz with the Montana Department of Public Health and Human Services,
Vital Statistics Section, provided the mortality data used in this report. The ATSDR
Spatial Activities and Analysis Group provided assistance in the geographic analysis of
mortality data presented herein.
Prepared by:
Steve Dearwent, MPH
Epidemiologist, Exposure Investigations Section
Exposure Investigations and Consultations Branch
Division of Health Assessment and Consultations
Co-Authors:
Rubina Imtiaz, MD
Medical Officer, Exposure Investigations Section
Exposure Investigations and Consultations Branch
Division of Health Assessment and Consultations
Susan Metcalf, MD
Chief, Exposure Investigations Section
Exposure Investigations and Consultations Branch
Division of Health Assessment and Consultations
Michael Lewin, MS
Mathematical Statistician
Health Investigations Branch
Division of Health Studies
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