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Proceedings of Workshop on Asbestos: Definitions and Measurement Methods Proceedings of a Workshop on Asbestos held at the National Bureau of Standards, Gaithersburg, Maryland, July 18-20, 1977 Edited by C. C. Gravatt, Philip D. LaFleur, and Kurt F. J. Heinrich National Measurement Laboratory National Bureau of Standards Washington, D.C. 20234 Sponsored by Nationat Bureau of Standards of the Department of Cemmerce and occupational Safety and Health Administration of the li.S. f?epartmen[ of IzMv U.S. DEPARTMENT OF COMMERCE, Juanita M. Kreps, Secretary Dr, Sadney Harman, Under Secretary Jordan J. Baruch, Assistant Secretary for Science and Technology NATIONAL BUREAU OF STANDARDS, Ernest Ambler, Director Issued November 1978 1.0

Library of Congress Catalog Card Number: 78-600109 National Bureau of Standards Special Publication 506 Nut. Bur. Stand. (U.S.), Spec. Publ. 506,490 P:agcs (Nov. 1978) COQEN:XNBSAV ~ U.S. GOVERNMENT PRINTING OFFICE WASEffiVGTON: 1978 ~ {4 O Cn W r+ O a J b CN

FOREWORD Asbestos is a generic name used to describe a variety of hydrated silicate materials which exist as fibers. Because "asbestos" resists heat and acids, is noncombustible, and can be woven into fabrics, it is a valuable industrial material. Asbestos has been known and used since ancient times. Today, it is used in some 3000 cortmercial applications, from potholders, to brake linings, to construction materials. Concern over the use of asbestos has arisen from studies which indicate an increased incidence of various serious diseases among people who work with it. Meaningful regulation requires proper definitions of workplace air concentrations of asbestos and effective measurement methods for these minerals. This Workshop was organized to evaluate the existing state-of- the-art in measuring "asbestos° and is part of an interagency program dealing with definitions and measurement methods for asbestos between the National Bureau of Standards of the Department of Commerce and the Occupational Safety and Neaith Administration of the Department of Labor. philip D. LaFleur, Chief Center for Analytical Chemistry iii

ers PREFACE This Workshop was organized to provide a forum for representatives of industrial corporations, trade associations, regulatory and other federal agencies, state and local agencies and other researchers to discuss asbestos definitions and measurement methods. The Workshop was divided into four topical areas: Mineralogical Aspects, the Relationships Between Chemical and Physical Properties and Health Effects, Analytical Methods, and Regulatory Aspects. The format of the Workshop included presentations of technical papers by invited experts, followed by verbal discussions. At the conclusion of each session there was a general discussion of the material presented. The general discussions served to define those factors for which there is general agreement, what points of controversy exist, and to identify additional research that is required to resolve the remaining problems. The following protocol was employed for the preparation of these proceedings. Each author/speaker submitted a written manuscript based on and containing the material given in the oral presentation. The questions, answers, and comments which followed each talk have been transcribed from the tape recordings made of the Workshop, edited both to remove extraneous material and to improve readability, but without changing the meaning. These discussion sections are printed immediately following the manuscript. The general discussions which followed each session have been similarly transcribed, edited, and printed at the end of each topic section. In addition, any questions, answers, comments, or discussion material which was submitted to the editors in writing has been inserted in the appropriate section of the Proceedings and the material has been designated as "submitted in writing - not in recording of Workshop." I wish to express my gratitude to all those who, through participation in the Workshop or preparation of these proceedings, made this undertaking a success. These proceedings were expertly typed and prepared by Mrs. Joy Shoemaker and members of her Text Editing Facility and the assistance of Mrs. Betty Garrigues in correcting proofs was invaluable. The able assistance of Ors. Ryna Marinenko and John Small in editing the Analytical Methods Session is gratefully acknowledged. It is hoped that these Proceedings will provide useful information to those currently involved in formulating measurement methods, definitions, and regulatory positions with respect to asbestos and other fibrous materials. C. C. Gravatt, Chief Gffice of Environmental Measurements iv

ABSTRACT This document contains invited papers which were given at a workshop on "Asbestos: Definitions and Measurement Methods" which was jointly sponsored by the National Bureau of Standards of the U. S. Department of Commerce and the Occupational Safety and Health Administration of the U. S. Department of Labor. The discussion portions of the Workshop also have been included as has written material appropriate to the topics under consideration which was submitted to the editors at a later date. The Workshop covered four major topics: Mineralogical Aspects, the Relationship Between Chemical and Physical Properties and Health Effects, Analytical Methods, and Regulatory Aspects. Also included in these Proceedings is a summary of each of these topics. These summaries serve to define those factors for which there was general agreement at the Workshop, identify remaining points of controversy, and, in some cases, describe additional research required to resolve remaining problems. Key Words: Amphibole; asbestos; fibers; light microscopy; mineralogical terminology; scanning electron microscopy; serpentine; talc; transmission elec- tron microscopy. v

TABLE OF CONTENTS PAGE FOREWOPO . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . i i i PREFACE ........................................ iv ABSTRACT. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . v SECTION I. MINERALOGICAL ASPECTS Chairman - Brian Mason, Smithsonian Institution, Washington, D. C. HISTORY OF ASBESTOS-RELATED MINERALOGICAL TERMINOLOGY . . . . . . . . . . . . . . . 1 Tibor Zoltai FIBROUS AND ASSESTIFORM MINERALS . . . . . . . . . . . . . . . . . . . . . . . . . 19 James R. Kramer THE CRYSTAL STRUCTURES OF AAIPHIBOLE AND SERPENTINE MINERALS. . . . . . . . . . . . 35 Jack Zussman THE "ASBESTOS" MINERALS: DEFINITIONS, DESCRIPTION, MODES OF FORMATION, PHYSICAL AND CHEMICAL PROPERTIES, AND HEALTH RISK TO THE MINING COMMUNITY ......... 49 Malcolm Ross GENERAL DISCUSSION OF MINERALOGICAL ASPECTS . . . . . . . . . . . . . . . . . . . . 65 SESSION II. RELATIONSHIP BETWEEN CHEMICAL AND PHYSICAL PROPERTIES AND HEALTH EFFECTS Chairman - Marvin Schneiderman, National Cancer Institute of the National Institutes of Health, Bethesda, Maryland EPIDEMIOLOGICAL EVIDENCE ON ASBESTOS . . . . . . . . . . . . . . . 71 W. J. Nicholson, A. M. Langer, and I. J. Selikoff MEASUREMENT OF ASBESTOS RETENTION IN THE HUMAN RESPIRATORY SYSTEM RELATED TO HE4LTH EFFECTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95 J. Bignon, P. Sebastien, and A. Gaudichet EPIDEMIOLOGIC EVIDENCE OF THE EFFECT OF TYPE OF ASBESTOS AND FIBER DIMENSIONS ON THE PRODUCTION OF DISEASE IN MAN . . . . . . . . . . . . . . . . . . . . . . . . 121 W. Clark Cooper PATHOPHYSIOLDGY IN RELATION TO THE CHEMICAL AND PHYSICAL PROPERTIES OF FIBERS. . . 133 Paul Kotin THE CARCINOGENICITY OF FIBROUS MINERALS . . . . . . . . . . . . . . . . . . . . . . 143 Mearl F. Stanton and Maxwell Layard NIEHS ORAL ASBESTOS STUDIES . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153 John A. Moore EPA STUDY OF BIOLOGICAL EFFECTS OF ASBESTOS-LIKE MINERAL FIBERS. ......... 163 0. L. Coffin and L. 0. Palekar A STUDY OF AIRBORNE ASBESTOS FIBERS IN CONNECTICUT . . . . . . . . . . . . . . . . 179 Leonard Bruckman GENERAL DISCUSSION OF RELATIONSHIP BETWEEN CHEMICAL AND PHYSICAL PROPERTIES AND HEALTH EFFECTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 191 vi

Table of Contents Continued SESSION`III. ANALYTICAL METHODS Chairman - K. Heinrich, Analytical Chemistry Division, National Bureau of Standards PAGE IDENTIFICATION OF SELECTED SILICATE MINERALS AND THEIR ASBESTIFORM VARIETIES . . . 201 William J. Campbell AN OVERVIEW OF ELECTRON MICROSCOPY METHODS . . . . . . . . . . . . . . . . . . . . 221 Clayton 0. Ruud IDENTIFICATION OF ASBESTOS BY POLARIZED LIGHT MICROSCOPY . . . . . . . . . . . . . 235 Walter C. McCrone MINERAL FIBER IDENTIFICATION USING THE ANALYTICAL TRANSMISSION ELECTRON MICROSCOPE . . . . . . . . . . . . . . . . . . . . . . . . . . . . 249 0. R. Beaman and H. J. Walker TRANSMISSION ELECTRON MICROSCOPICAL METHODS FOR THE DETERMINATION OF ASBESTOS. . . 271 Ian M. Stewart STATISTICS AND THE SIGNIFICANCE OF ASBESTOS FIBER ANALYSES . . . . . . . . . . . . 281 J. P. Leineweber SELECTION AND CHARACTERIZATION OF FIBROUS AND NONFIBROUS AMPHIBOLES FOR ANALYTICAL METHODS DEVELOPMENT . . . . . . . . . . . . 295 J. C. Haartz, B. A. Lange, R. G. Draftz, and R. F. Scholl ASGESTIFORM MINERALS IN INDUSTRIAL T.RLCS: COMMERCIAL DEFINITIONS VERSUS INDUSTRIAL HYGIENE REALITY . . . . . . . . . . . . . . . . . . . . . . . . . . . . 313 John M. Dement THE DETECTION AND IDENTIFICATION OF ASBESTOS AND ASBESTIFORM MINERALS IN TALC. . . 325 Harold 0. Stanley MISIDENTIFICATION OF ASBESTOS IN TALC . . . . . . . . . . . . . . . . . . . . . . 339 Jerome B. Krause and William H. Ashton AMBIENT AIR MONITORING FOR CHRYSOTILE IN THE UNITED STATES . . . . . . . . . . . . 355 Richard J. Thompson ENVIRONMENTAL PROTECTION AGENCY INTERIM METHOD FOR DETERMINING ASBESTOS IN WATER. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 365 Charles H. Anderson INTER-LABORATORY MEASUREMENTS OF AMPHIBOLE AND CHRYSOTILE FIBER CONCENTRATION IN WATER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 377 K. S. Chopra THE STANDARD FOR OCCUPATIONAL EXPOSURE TO ASBESTOS BEING CONSIDERED BY ASTM COMMITTEE E-34. . . . . . . . . . . . . . . . . . . . . . . . . . . . 381 M. Cossette and A. A. Winer IDENTIFICATION AND COUNTING OF MINERAL FRAGMENTS . . . . . . . . . . . . . . . . . 387 R. J. Lee, J. S. Lally, and R. M. Fisher PRACTICAL ASPECTS OF TALC AND ASBESTOS . . . . . . . . . . . . . . . . . . . . . . 403 C. J. Parmentier and G. J. Gill GENERAL DISCUSSION OF ANALYTICAL METHODS . . . . . . . . . . . . . . . . . . . . . 413 Vii 20631.04801

Table of Contents Concluded PAGE SESSION IV. REGULATORY ASPECTS Chairman - John Martonick, Occupational Safety and Health Administration, Washington, D. C. I NTRODUCTI ON . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 421 John Martonick THE MINING ENFORCEMENT AND SAFETY ADMINISTRATION - REGULATIONS AND METHODS .... 423 Aurel Goodwin QCCUPATIGNAL SAFETY AND HEALTH ADMINISTRATION METHDDS . . . . . . . . . . . . . . . 431 Willard C. Dixon FDA PROJECTS AND METHODS . . . . . . . . . . . . . . . . . . . 441 J. A. Wenninger, I. M. Asher, and P. McGrath CPSC REGULATION OF NON-OCCUPATIONAL EXPOSURE TO ASBESTOS IN CONSUMER PRODUCTS. . . 451 Robert M. Hehir, Steven P. Bayard, and June Thompson IMPACT OF ASBESTOS REGULATIONS ON THE MINING INDUSTRY . . . . . . . . . . . . . . . 461 C. S. Thompson GENERAL DISCUSSION OF REGULATORY ASPECTS . . . . . . . . . . . . . . . . . . . . . 469 LIST OF ATTENDEES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 479 Disclaimer: Certain trade names and company products are identified in order to adequately specify the experimental procedure. In no case does such identification imply recoomend- ation or endorsement by the National Bureau of Standards, nor does it imply that the pro- ducts are necessarily the best available for the purpose. N w ~ 0 N

National Bureau of Standards Special Publication 506. Proceedings of the Workshop on Asbestos: Definitions and Measurement Methods held at NBS, Gaithersburg, MD, July 18-20, 1977. (Issued November 1978) HISTORY OF ASBESTOS-RELATED MINERALOGICAL TERMINOLOGY Tibor Zoltai Department of Geology and Geophysics University of Minnesota Minneapolis, Minnesota 55455 Abstract Asbestos-related mineralogical terms such as fiber, fibrous, orm asbestos-like, and asbestos have been misinterpreted and ing the last few years in the literature of environmental MNAand public health studies. The new definitions are inadequate for the proper description and study of various mineral particles and, at the same time, are causing considerable confusion in interdisciplinary communication. The meaning of these terms is traced through the history of mineralogy. It is demonstrated that: the use of the•term fiber has always required some resemblance to organic fibers; fibrous has been the term describing a crystallization habit in which the mineral appears to be composed of fibers; asbestiform has been used, without exception, to describe a special fibrous habnt in which the fibers have higher tensile strength and flexibility than crystals in other habits of the same mineral; asbestos was initially the name of an independent mineral species and gradually became a collective term applied to all asbestiform varieties of minerals. Ney words: Acicular; amphibole; asbestiform; asbestos; fiber; fibrous; fragments; mineralogical; serpentine; terminology. Introduction Until a few years ago there was no problem with the asbestos-related mineralogical terminology. Mineralogists knew exactly what other mineralogists meant when they used terms like asbestos, asbestiform, fibrous, and acicular, even if some of these terms, like asbestiform, are not always defined in textbooks. The last syllable of asbestiform (that is, -form) is consistent with several adjectives used for the description of textures or crysta~Tazation habits (e.g., reniform, filiform, dentiform, coiloform). Consequently, it is understood, without question, that asbestiform is a descriptive term for a certain texture or crystallization habit. This situation of content was suddenly changed less than five years ago, when through the focusing of public and scientific attention on asbestos pollution this portion of the mineralogical terminology was picked up by environmental and public health scientists, by engineers and by lawyers. Unfortunately, they did not adopt the terminology as used by mineralogists but have introduced a redefinition of most of the critical expressions, in spite of the objection of leading mineralogists. The most important of these arbitrary changes of definitions included: (1) Asbestos is understood by mineralogists as a collective term referring to the unusual crys~Tization of certain minerals in the form of long, strong, and flexible fibers, aggregated in parallel or radiating bundles from which the fibers can easily be 2063104803

separated. The definition accepted by the Minnesota District Court during the trial of Reserve Mining Co. [63, p. 24],t however, was a different one: Asbestos is a generic term for a number of hydrated silicates that, when crushed or processed, separate into flexible fibers made up of fibrils. (emphasis by the author) By this definition ali amphiboles and a number of other minerals became possible candidates for inclusion in the term asbestos. Because of the perfect prismatic cleavage, upon crushing, amphiboles always produce acicular fragments. Of course, acicular fragments are not fibers, are not flexible and are not composed of fibrils. However, they may not be distinguishable from asbestos fibers in routine electron microscopic examination. In order to get around that problem the term fiber had to be defined in a more practical sense. (2) The redefinition of fiber (U.S. District Court, District of Minnesota, Fifth Division, Fall, 1973) that was soon adopted by most environmental and public health scientists [28, p. 5] states that a fiber is: a mineral which is at least three times as long as it is wide.2,a This definition of fiber eliminated the difficult task of testing the flexibility and the presence of fibril composition of submicroscopic particles, and retained only the shape of the particle as a decisive criterion. Accordingly, all acicular amphibole cleavage fragments became fibers and as indirectly implied, all amphibole minerals became asbestos. (3) Leading mineralogists objected to calling amphibole cleavage fragments, asbestos fibers and amphiboles, asbestos minerals. In order to overcome that objection two less frequently used terms, "asbestiform" and "asbestos-like", were redefined in line with the new definitions of asbestos and fiber. The new definitions were introduced in the Minnesota courtroom [63], and subsequently in the language of the news media and the environmental literature: Asbestiform became a prefix added to the name of any mineral which is known to occur on occasion andlor produce "fibers" when crushed. Asbestos-like was defined as any hydrous silicate particle which is at least threeT nger than wide, that is, which is a°fiber". Thus, all amphiboles became asbestiform minerals,° instead of asbestos minerals, and amphibole fragments became asbestos-like fibers, underscoring its implied relationship with asbestos. These new definitions provided a simplified mineralogical interpretation for the complex and not fully resolved problem of asbestos mineralogy. It simplified the identification of mineral particles by eliminating the need for distinction between asbestos fibers and acicular cleavage fragments. A fiber can simply be identified by its shape (>3:1 aspect 1Figures in brackets indicate the literature references at the end of this paper. 2The 3>1 aspect ratio limitation In the description of fibers was used before by some British and American regulatory agencies. However, this was the first incident when this fiber description became an asbestos fiber identification, as the use of the term fiber im~plfed an identity between appropriately shaped amphibole fragments and amphibole asbestos fibers. This implicative use of the 3>1 aspect ratio is apparent in most current environmental studies. 311; should be noted that sedimentologists use the term acicular for the description of particles "whose length is more than three times its width"T2-f7.p_5]. 4The expression "asbestiform amphiboles" is basically valid. However, in the context of the new definitions it is erroneous as it includes all amphiboles. According to the proper mineralogical terminology the same expression 7s limited to those amphibole crystals'which actually grew in the asbestiform habit. 2