Asbestiform Fibers -- Copyright -- Preface -- References -- Contents -- Executive Summary -- ORIGIN OF THE STUDY -- MAJOR FINDINGS AND RECOMMENDATIONS -- Evaluation of Risk -- Physicochemical Properties and Health Effects -- Recommendations -- SUMMARY OF THE STUDY -- Background -- Materials of Concern -- Relationship of Fiber Characteristics to Health Effects -- Measurement and Extent of Exposure -- Health Effects Methodology -- Health Effects of Asbestos -- Health Effects of Nonasbestos Asbestiform Fibers -- Evidence Associating Fiber Properties with Adverse Health Effects -- Risk Assessments -- 1 Introduction -- CONCURRENT NATIONAL RESEARCH COUNCIL AND GOVERNMENT ACTIVITIES RELATED TO ASBESTOS -- THE COMMITTEE'S APPROACH -- REFERENCES -- 2 Asbestiform Fibers: Historical Background, Terminology, and Physicochemical Properties -- ASBESTOS IN HISTORY -- MINERALOGICAL TERMINOLOGY -- SOURCES OF MINERAL PARTICLES -- PHYSICAL PROPERTIES OF ASBESTIFORM FIBERS -- Fiberlike Morphology -- Enhanced Strength and Flexibility -- Diameter-Dependent Strength -- Increased Physical and Chemical Durability -- Defect-Free Surface Structure -- Growth-Dependent Fiber Quality -- BIOLOGICALLY RELEVANT PHYSICOCHEMICAL PROPERTIES -- Respirability -- Size and Aspect Ratio (Length:Diameter) -- Durability -- Flexibility and Tensile Strength -- Chemical Composition -- Surface Area -- Surface Charge -- Standardized Asbestos Samples -- SUMMARY -- RECOMMENDATIONS -- REFERENCES -- 3 Assessing Nonoccupational Exposures to Asbestiform Fibers -- DEFINITIONS OF EXPOSURE -- ASBESTIFORM FIBERS AND THEIR SOURCES -- EXPOSURE POTENTIAL FOR ASBESTOS -- Types of Exposure -- Quantitative Exposure Estimates -- EXPOSURE TO OTHER NATURAL MINERAL FIBERS -- Attapulgite -- Erionite -- EXPOSURE TO MAN-MADE FIBERS -- Man-Made Mineral Fibers -- Exposure to Other Man-Made Fibers.

SUMMARY AND RECOMMENDATIONS -- REFERENCES -- 4 Measurement of Exposure to Asbestiform Fibers -- MEASUREMENT TECHNIQUES -- MEASURING ASBESTOS DUST IN THE WORKPLACE -- The Impinger Technique -- The Membrane Filter Technique -- MEASURING ASBESTOS DUST IN THE AMBIENT ENVIRONMENT -- RELATIONSHIPS AMONG VARIOUS EXPOSURE MEASUREMENT METHODS -- EXPOSURE TO CHRYSOTILE IN THE AMBIENT ENVIRONMENT -- COMPLICATING FACTORS IN ENVIRONMENTAL ASSAYS -- FUTURE MEASUREMENT OF EXPOSURE TO ASBESTIFORM FIBERS -- RECOMMENDATIONS -- REFERENCES -- 5 Effects of Asbestiform Fibers on Human Health -- NATURE OF EVIDENCE -- BIODISPOSITION OF FIBERS -- Fiber Deposition -- Clearance and Transport -- CLINICAL ASPECTS OF ASBESTOS-ASSOCIATED DISEASES -- Necessary Assumptions Used in Determining Health Effects -- Sensitivity and Specificity of Clinical Evidence -- General Diagnostic Measures -- DISEASE ASSOCIATED WITH NONOCCUPATIONAL INHALATION EXPOSURES TO ASBESTIFORM FIBERS -- Asbestos Exposure from Household Contacts -- Neighborhood Exposure to Asbestos -- Natural Sources of Asbestiform Fibers -- Summary -- EPIDEMIOLOGICAL STUDIES OF EFFECTS RESULTING FROM THE INGESTION OF ASBESTOS IN DRINKING WATER -- OCCUPATIONAL EPIDEMIOLOGICAL STUDIES-METHODOLOGICAL CONSIDERATIONS -- CANCER MORTALITY IN OCCUPATIONAL COHORTS EXPOSED TO ASBESTOS -- Mining and Milling -- Manufacturing -- Insulation -- Shipyards -- Relative Carcinogenicity of Different Types of Asbestos -- Effects of Smoking -- Summary -- ASBESTOSIS AND ASBESTOS-ASSOCIATED PLEURAL DISEASE IN OCCUPATIONAL COHORTS -- Mortality Studies -- Morbidity Studies -- Summary -- HEALTH EFFECTS OF OCCUPATIONAL EXPOSURE TO MAN-MADE MINERAL FIBERS12 -- Morbidity -- Mortality -- Summary -- ADDITIONAL OCCUPATIONAL EPIDEMIOLOGICAL STUDIES -- Attapulgite -- Talc -- RECOMMENDATIONS -- REFERENCES.

6 Laboratory Studies of the Effects of Asbestiform Fibers -- STUDIES IN ANIMALS -- Lung Cancer -- Mesothelioma -- Fibrosis -- Events in the Gastrointestinal Tract After Exposure to Asbestos -- IN VITRO STUDIES -- Hemolytic Assays -- Cytotoxicity Studies -- Alterations in Cells of the Immune System After Exposure to Asbestiform Fibers -- Effects on Fibroblasts In Vitro -- INITIATION-PROMOTION MODEL OF CARCINOGENESIS -- Interaction of Asbestiform Fibers with DNA -- Tumor Promotion -- In Vitro Studies with Mesothelial Cells -- Interactions Between Fibers and Polycyclic Aromatic Hydrocarbons (PAHs) -- CONCLUSIONS -- Asbestiform Fibers: Initiators and/or Promoters of Lung Tumors? -- Asbestiform Fibers: Initiators and/or Promoters of Malignant Mesothelioma? -- Asbestiform Fibers: Possible Mechanisms of Fibrosis -- SUMMARY -- RECOMMENDATIONS -- REFERENCES -- 7 Risk Assessment -- THE PROCESS OF RISK ASSESSMENT -- QUANTITATIVE RISK ASSESSMENT -- Mathematical Model For Carcinogenic Risk Estimate -- PUBLISHED RISK ASSESSMENTS -- Lung Cancer Risk from Nonoccupational Environmental Exposures -- Mesothelioma Risk from Nonoccupational Environmental Exposures -- QUANTITATIVE RISK ASSESSMENT FOR NONOCCUPATIONAL ENVIRONMENTAL EXPOSURES -- Lifetime Risk Estimates For Lung Cancer and Mesothelioma -- Risk Assessments For Special Subpopulations -- COMPARATIVE RISK ASSESSMENT -- Methods -- General Methodological Considerations -- Scoring Considerations -- Discussion of Comparative Risks -- SUMMARY AND RECOMMENDATIONS -- REFERENCES -- Appendix A Asbestos Exposure and Human Disease. Hallmark Observations and Studies From 1898 to 1979 -- REFERENCES -- Appendix B Natural and Synthetic Fibrous Substances and Some of their Known Biological Effects -- REFERENCES -- Appendix C Fiber-Quality Parameters of Selected Asbestos, Whisker, and Glass Fibers.

SIGNIFICANCE OF THE FIBER-QUALITY PARAMETERS -- REFERENCES -- Appendix D Conceptual Model of Fiber Exposure -- SUMMARY -- REFERENCES -- Appendix E Epidemiological Studies Among Cohorts Exposed To Asbestos -- Appendix F Effects of Administering Asbestiform Fibers to Animals -- Appendix G Development of Some Equations Used for Quantitative Risk Assessment -- REFERENCE -- Appendix H Comparative Risk Assessment Score Sheets -- EXPOSURE -- BIODISPOSITION -- EFFECTS -- Appendix I Background Information on Members of the Committee on Nonoccupational Health Risks of Asbestiform Fibers.