Applying Definitions of “Asbestos” to Environmental and “Low-Dose” Exposure Levels and Health Effects, Particularly Malignant Mesothelioma

Abstract

Although asbestos research has been ongoing for decades, this increased knowledge has not led to consensus in many areas of the field. Two such areas of controversy include the specific definitions of asbestos, and limitations in understanding exposure-response relationships for various asbestos types and exposure levels and disease. This document reviews the current regulatory and mineralogical definitions and how variability in these definitions has led to difficulties in the discussion and comparison of both experimental laboratory and human epidemiological studies for asbestos. This review also examines the issues of exposure measurement in both animal and human studies, and discusses the impact of these issues on determination of cause for asbestos-related diseases. Limitations include the lack of detailed characterization and limited quantification of the fibers in most studies. Associated data gaps and research needs are also enumerated in this review.

Acknowledgments

The authors thank Dr. Phil Cook, Dr. Ron Dodson, Dr. Ann Aust, Dr. Urmila Kodavanti, and Amy Madl for an in-depth review and discussion of this document. This state-of-the-science review document was created in support of the NIEHS workshop “Asbestos: A Science-Based Examination of the Mode of Action of Asbestos and Related Mineral Fibers.” However, the views expressed in this document are those of the authors and do not necessarily represent the views and/or policies of the federal agencies involved in its production (U.S. Geological Society, U.S. Environmental Protection Agency, National Institute of Environmental Health Sciences, Agency for Toxic Substances and Disease Registry and the National Institute for Occupational Safety and Health). Dr. Case has acted and/or is currently acting as an expert witness or consultant for law firms representing defendants and plaintiffs in asbestos litigation and compensation board proceedings, and has been a paid and unpaid consultant to regulatory and medical agencies and compensation boards in North America, including but not limited to the U.S. EPA, ATSDR, ATS, nongovernmental organizations (NGOs), and individual and collective citizen groups concerned with asbestos exposure and disease. He has also received (and is likely to apply in the future for) competitive-funding research grants from U.S. and Canadian publicly financed, peer-reviewed grant approval process agencies concerning asbestos exposure and disease, including topics covered in all aspects of the workshop, including but not limited to research support from EPA, NCI of Canada, Canadian Institutes of Health Research (formerly Medical Research Council of Canada), Quebec and American Lung Associations, and the Quebec National Institute for Public Health (INSPQ). Dr. Abraham has acted and/or is currently acting as an expert witness or consultant for law firms representing plaintiffs and defendants in asbestos litigation and compensation board proceedings, and has been a paid and unpaid consultant to regulatory and medical agencies and compensation boards in North America, including but not limited to the U.S. EPA, ATSDR, ATS, NGOs, and individual and collective citizen groups concerned with asbestos exposure and disease. He has also received (and may also apply in future for) competitive-funding research grants from U.S. publicly financed, peer-reviewed grant approval process agencies concerning asbestos exposure and disease, including topics covered in all aspects of the workshop, including but not limited to research support from the U.S. EPA and American Lung Association.

Notes

¹See Pooley. (1987).