Developments in asbestos cancer risk assessment


  • Michael A. Silverstein MD, MPH,

    Corresponding author
    1. Department of Environmental and Occupational Health Sciences, University of Washington School of Public Health, Seattle, Washington
    • Clinical Professor, Environmental & Occupational Health Sciences, University of Washington School of Public Health, 3312 French Loop NW, Olympia, WA 98502.
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  • Laura S. Welch MD,

    1. CPWR—The Center for Construction Research and Training, Silver Spring, Maryland
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  • Richard Lemen PhD, MSPH

    1. US Public Health Service, National Institute for Occupational Safety and Health (ret.), Atlanta, Georgia
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  • Conflict of interest: Each of the authors has provided expert witness testimony and/or reports in litigation where issues regarding the carcinogenic potency of asbestos have been raised.



Efforts have been made for 25 years to develop asbestos risk assessments that provide valid information about workplace and community cancer risks. Mathematical models have been applied to a group of workplace epidemiology studies to describe the relationships between exposure and risk. EPA's most recent proposed method was presented at a public meeting in July 2008.


Risk assessments prepared by USEPA, OSHA, and NIOSH since 1972 were reviewed, along with related literature.

Results and Conclusions

None of the efforts to use statistical models to characterize relative cancer potencies for asbestos fiber types and sizes have been able to overcome limitations of the exposure data. Resulting uncertainties have been so great that these estimates should not be used to drive occupational and environmental health policy. The EPA has now rejected and discontinued work on its proposed methods for estimating potency factors. Future efforts will require new methods and more precise and reliable exposure assessments. However, while there may be genuine need for such work, a more pressing priority with regard to the six regulated forms of asbestos and other asbestiform fibers is to ban their production and use. Am. J. Ind. Med. 52:850–858, 2009. © 2009 Wiley-Liss, Inc.