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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.


  • 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.

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

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


  1. Schneider A. A town left to die. Seattle Post-Intelligencer online 1999 November 18. Available at: lib18.shtml

  2. Gilman J. 1990. PM-10 chemical mass balance study for Libby, Montana. Helena, MT: Air Quality Bureau, Department of Health and Environmental Sciences.

  3. Atkinson GR, Rose D, Thomas K, Jones D, Chatfield EJ, Going JE. 1982. Collection, analysis and characterization of vermiculite samples for fiber content and asbestos contamination. MRI report for EPA, project No. 4901-A32 under EPA contract 68-01-5915.

  4. Agency for Toxic Substances and Disease Registry. Health consultation concerning tremolite. Atlanta: US Department of Health and Human Services; 2000 April.

  5. Amandus HE, Wheeler PE, Jankovic J, Tucker J. 1987a. The morbidity and mortality of vermiculite miners and millers exposed to tremolite-actinolite: Part I. Exposure estimates. Am J Ind Med 11:1-14.

  6. Case BW. 1991. Health effects of tremolite: now and in the future. Ann N Y Acad Sci 643:491-504.

  7. Lockey JE, Brooks SM, Jarabek AM, Khoury PR, McKay RT, Carson A, Morrison JA, Wiot JF, Spitz HB. 1984. Pulmonary changes after exposure to vermiculite contaminated with fibrous tremolite. Am Rev Respir Dis 129:952-58.

  8. Exposure assessment for asbestos-contaminated vermiculite. EPA contract no. 68-01-6271 and 68-02-3968; 1985 Feb.

  9. US Environmental Protection Agency, Region VIII. Action memorandum (draft) for the Libby asbestos site - export plant and screening plant former processing areas; Libby, MT: 2000, May 4.

  10. McDonald JC, McDonald AD, Armstrong B, Sebastien P. 1986a. Cohort study of mortality of vermiculite miners exposed to tremolite. Br J Ind Med 43:436-44.

  11. Cooke WE. 1924. Fibrosis of the lungs due to the inhalation of asbestos dust. Br Med J 2:147.

  12. Cooke WE. 1927. Pulmonary asbestosis. Br Med J 2:1024-5.

  13. Lynch KM, Smith WA. 1935. Pulmonary asbestosis. III. Carcinoma of the lung in asbestosis-silicosis. Am J Cancer 14:56-64.

  14. Selikoff IJ, Churg J, Hammond EC. 1964. Asbestos exposure and neoplasia. JAMA 188:22-6.

  15. Selikoff IJ, Hammond EC, Seidman H. 1979. Mortality experience of insulation workers in the United States and Canada. Ann N Y Acad Sci 330:91-116.

  16. Amandus HE, Wheeler R. 1987b. The morbidity and mortality of vermiculite miners and millers exposed to tremolite-actinolite: Part II. Mortality. Am J Ind Med 11:15-26.

  17. Amandus HE, Althouse R, Morgan WK, Sargent EN, Jones R. 1987c. The morbidity and mortality of vermiculite miners and millers exposed to tremolite-actinolite: Part III. Radiographic findings. Am J Ind Med 11:27-37.

  18. McDonald JC, Sebastien P, Armstrong B. 1986b. Radiological survey of past and present vermiculite miners exposed to tremolite. Br J Ind Med 43:445-9.

  19. Anderson HA, Lilis R, Daum SM, Selikoff IJ. 1979. Asbestosis among household contacts of asbestos factory workers. Ann N Y Acad Sci 330:387-99.

  20. Yazicioglu S, Ilcayto R, Balci K, Sayli BS, Yorulmaz B. 1980. Pleural calcification, pleural mesothelioma, and bronchial cancers caused by tremolite dust. Thorax 35:564-9.

  21. Zeren EH, Gümürdülü D, Roggli VL, Tuncer I, Zorlundemir S, Erkisi M. 2000. Environmental malignant mesothelioma in southern Anatolia: a study of fifty cases. Environ Health Perspect 108:1047-50.

  22. ProCD Select Phone 2000 Edition.

  23. Checkoway, Pearce, Crawford-Brown. 1989. Research methods in occupational epidemiology. New York: Oxford Press. p. 128-9.

  24. Egilman D, Reinert A. 1996. Lung cancer and asbestos exposure: asbestosis is not necessary. Am J Ind Med 30:398-406.

  25. Samet J. 2000. Does idiopathic pulmonary fibrosis increase lung cancer risk? Am J Respir Crit Care Med 161:1-2.

  26. Feigley P, Montana Department of Public Health and Human Services, Chronic Disease Prevention and Health Promotion, BRFSS Coordinator, personal communication, 2000.

  27. Kircher T, Nelson J, Burdo H. 1985. The autopsy as a measure of accuracy of the death certificate. N Engl J Med 313:1263-9.

  28. Selikoff IJ. 1992. Use of death certificates in epidemiological studies, including occupational hazards: discordance with clinical autopsy findings. Am J Ind Med 22:469-80.

  29. Newhouse ML, Berry G, Wagner JC. 1985. Mortality of factory workers in East London 1933-1980. Br J Ind Med 42:4-11.

  30. Connelly RR, Spirtas R, Myers MH, Percy CL, Fraumeni JF, Jr. 1987. Demographic patterns for mesothelioma in the United States. JNCI 78:1053-60.

  31. Nelson DE, Swanson GM, Schwartz AG, Brix K, Fine LF. 1987. Occupation and industry data obtained from death certificates: the effect and influence of case selection. J Occup Med 29:52-6.

  32. Davis LK, Martin TR, Kligler B. 1992. Use of death certificates for mesothelioma surveillance. Public Health Rep 107:481-3.

  33. The Pew Environmental Health Commission, Environmental Health Tracking Team. "America's environmental health gap: why the country needs a nationwide health tracking network, " 2000 Sept. Available at: http://pewenvirohealth. pewtrackingtechnical.pdf

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