Document o917X5MjEzg61E0xwp9d17J5R

ASBESTOS INFORMATION ASSOCIATION NORTH AMERICA 1835 K Street, N.W., Washington, D.C. 20006 (202) 223-4885 27 April 1977 Memorandum For: B. Iwarsson, Abex Corporation W. Jones,. Safeguard Automotive Corp. J. Marsh, Raybestos-Manhattan, Inc. J. Riopelle, Bendix Corporation W~ Sleeth, Royal Industries E. Zacharias, Molded Materials Company Subject: EPA Contracted Study with Syracuse University Research Corp -- Friction Materials In May of 1975 the Environmental Protection Agency contracted with Syracuse University Research Corp. for an Industrial Chemical Market Input/Output Profile in connection with studies of its Office of Toxic Substances. The contract (initially listed in the amount of $99,700) has been discontinued because of lack of funds, we have learned. However, on the subject of asbestos in the study, the general sections, and a section on friction materials were completed and submitted to EPA in draft form. This material is forwarded as a matter of interest. Please be advised that the paper is in draft form and has not been formally released by EPA. Therefore, it should not be quoted. The work by Syracuse University Research Corp. appears to be of high quality. Your comments will be appreciated. . H: il~reness Executive Director cc: Standards & Technical Committee (Rhodes, Weaver,Weber, Fenner) Mr. Drislane, FMSI RH.M: v Enclosures FMSI 06117 1 r I 1 l l I I l I 1 l l l I l LIST OF TABLES Number 2.1 Approximate Chemical Formula of the Asbestoses 5 2.2 Chemical Compos.ition of Common Fibrous Silicate Minerals 6 2.3 Chemical Composition of Asbestoses from Different Geographic 8 Locations 2.4 Physical, Chemical, and Mineralogical Properties of Varieties 9 of Asbestos 2.5 Chrysotile Grades by the Quebec Standard Test 2.6 Modifications in Grading American Mined Asbestos 3.1 Captive Fiber Sources for the Major American Asbestos Product Manufacturing Firrr$ 13 15 22 3.2 Twenty of the Largest U.S. Asbestos Product Manufacturers 23 3.3 Asbestos-Based Activity of Some Najar Asbestos-Manufacturing 24 Companies 3.4 3.5 3.6 3. 7 4.1 4.2 4.3a 4.3b 4.4 Industry Specialization and Primary Product Class Specialization for Asbestos Product Producing Establishments: 1972 Asbestos Products Manufacture: Distribution of Plant Sizes Asbestos Products Hanufacturing: Total Employment as a Function of Size of Facilities Asbestos Products Hanufacturing: Total Value of Shipments as a Function of Size of Facilities Mine Production of Asbestos U.S. Export of Asbestos (Unmanufactured) for 1965- 1975 U.S. Export-- By Country -- of Asbestos (Unmanufactured) in 1975 U.S. Export-- By Country-- of Asbestos (Unmanufactured) from January, 1976, to June, 1976 U.S. Exports --By Country --of Asbestos Hanufactured Products in 1975 25 27 27 28 31 32 33 34 35 v FMSI 06118 l r List of Tables (Cont'd) I Number 1 4.5 U.S. Imports of Asbestos (Unmanufactured) for 1965 - 1975 40 4.6a U.S. Imports --By Country -- of Unmanufactured Asbestos in 1975 42 4.6b U.S. Imports -- By Country -- of Unmanufactured Asbestos, 43 l January to June, 1976 4.7 U.S. Imports for Consumption of Asbestos 44 I 4.8 U.S. Imports --By Country-- of Unmanufactured Asbestos 45 Products in 1975 I 4.9 Asbestos Supply-Demand Relationships, 1965-75 (Thousand 46 short tons) 4.10 Asbestos Distribution by End Use, Grade, and Type, 1974 (Short tons) 46 l 4.11 Buyers of Asbestos and Asbestos Ore 4.12 Time-Price Relationship for Asbestos 47 49 'I 4.13 Recent Prices of Various Asbestoses 50 4.14 Projections and Forecasts for U.S. Asbestos Demand by End Use, 1973 and 2000 (Thousand short tons) 51 5.1 6.1 6.2 6.3 6.4a 6.4b 6.5 American Asbestos Mines and Hills Value of Shipments of Asbestos Friction Materials U.S. Manufacturers of Asbestos-Bearing Friction Materials Binders and Property Modifiers in Automotive Brake Linings Average Brake Lining Composition Brake Lining Compositions from Patent Literature Sununary of Published Data - Asbestos Emissions "f-rom Brake Lining Use 55 60 62 76 78 79 82 6.6 Estimated Asbestos Emissions by Jacko and DuCharme (1973) 90 from Vehicles I I vi FMSI 06119 List of Tables (Cont'd) Number 6.7 6. B 6.9 Estimated Asbestos Emissions from Vehicles Using Rohl et al. (1976) Figures for Asbestos Content of Wear Debris ---- Asbestos Concentration During Automobile and Truck Brake Service Asbestos-Free Composition of a Disc Brake Pad 92 94 97 i L.. .. l. r. ! l l L vii FMSl 06120 r 1 1l [ LIST OF FIGURES 1 Number r 2.1 Schematic Diagram of the Structure of a Chrysotile Fibre Formed of Several Scrolls of Individual Crystallites 3 1 2.2 Schematic Diagram of the Crystal Structure of an Amphibole 4 Fiber, Indicating the Unit Cell Based on x7si8o22 (OH) 2 3.1 Asbestos Industry Structures I 3.2 Asbestos Products Industry 19 20 I 4.1 Asbestos - Salient Statistics 4.2 U.S. Asbestos Demand, and Projected Trends to 2000 30 48 i 5.1 Possible Areas of Asbestos Deposits 53 ifI 5.2 Asbestos Mines in the United States 54 5.3 Quebec Production Trends, From Analysis of 1951 - 1970 Data 57 [ 6.1 Geographical Dispersion of U.S. Friction Materials Plants 66 6.2 Dry-Nixed Brake Lining Manufacturing Operations 69 I- 6.3 Wet-Mixed Molded Brake Lining Manufacturing Operations 71 6.4 Holded Clutch Facings Manufacturing Operations [ 6.5 Woven Clutch Facings Manufacturing Operations 72 74 [ I_ It il l viii :L FMSI 06121 I 1 TR 77-515 (. I DRAFT l l CHEMICAL MARKET INPUT/OUTPUT ANALYSIS OF ASBESTOS TO ASSESS SOURCES l OF ENVIRONMENTAL CONTAMINATION [ William M. Meylan Philip H. Howard Sheldon S. Lande Center for Chemical Hazard Assessment Syracuse Research Corporation I Merrill Lane Syracuse, New York 13210 I Contract No. 68-01-3224 - Task III SRC No. Ll273-08 March 1977 Project Officer - Robert J. Carton Prepared for: Office of Toxic Substances U.S. Environmental Protection Agency Washington, D.C. 20460 ( I FMSI 06122 t I { NOTICE J This document is a preliminary draft. It has not been formally released f by EPA and should not at this stage be construed to represent Agency policy. It is being circulated for comment on its technical accuracy and policy impli- i cations. r f. l l l l 1 1 l f l r t ii FMSI 06123 I I TABLE OF CONTENTS I I 1.0 INTRODUCTION 1 [ 2.0 DESCRIPTION OF ASBESTOS 2.1 Composition and Properties of Asbestos 2.2 Asbestos Grading I 2.3 Major Uses of the Asbestoses 2.3.1 Chrysotile I 2.3.2 Crocidolite 2.3.3 Amosite 2.3.4 Tremolite and Actinolite 2.3.5 Anthophyllite [ 3.0 DESCRIPTION OF THE ASBESTOS INDUSTRY 2 2 11 12 12 17 17 18 18 19 I 3.1 Industry Structure 3.2 Types of Plants 3.3 Numerical and Percentage Distribution of Plants, Employees, 19 24 26 I and Production 4.0 MARKET INPUT/OUTPUT DATA 29 4.1 Mine Production 4.2 Exports 4.3 Imports ( 4.4 Supply-Demand-Use 4.5 Asbestos Fiber Prices 4.6 Future Outlook 29 32 40 41 41 48 I 5. 0 MINING AND MILLING 5.1 U.S. Mines and Hills I 5.1.1 Ore Characteristics 52 52 56 I 6.0 FRICTION MATERIALS 6.1 Statistics 59 59 6.1.1 I 6.1.2 6.1.3 r 6.1.4 Use Quantity and Shipment Values Industrial Firms Plants Future Projections for Asbestos (Clifton, 1975) 59 61 65 67 1 iii FMSI 06124 r Table of Contents (Cont'd) I I 6.2 Manufacturing Process Technology 6.2.1 Molded Products I 6.2.1.1 Dry-Mix Process 6.2.1.2 Wet-Mi;K Process I 6.2.2 Woven Products [ 6.3 Composition of Friction Materials 6.3.1 Binders 6.3.2 Property Modifiers 68 68 68 68 70 73 75 75 6.3.2.1 Non-Abrasive Modifiers 6.3.2.2 Abrasive Modifiers 75 77 6.3.3 Composition 6.3.4 Summary ( 6.4 Asbestos Emissions from Brake Lining Use 6.4.1 Published Literature 78 78 80 81 6.4.1.1 Discrepancies in Asbestos Content of 81 Emissions or Debris l 6.4.1.2 Collection Methodologies and Particle Size Distribution 6.4.1.3 Analysis Techniques 85 86 6.4.1.4 Other Ccnsiderations 88 6.4.2 Emission Quantities 6.4.3 Human Exposure to Asbestos Emissions During Brake Lining Maintenance and Repair 89 91 6.5 Alternatives to Asbestos as a Friction Material 94 6.5.1 6.5.2 6.5.3 6.5.4 The Role of Asbestos in Friction Linings Alternatives in Brake Linings Alternatives in Disc Brake Pads Alternatives in Clutches 94 95 96 97 6.6 Summary and Conclusions for Asbestos Friction Applications 98 l REFERENCES 101 iv l FMSI 06125 \I I ;1 i( I 1I J I :[ il 1 ![ List of Tables (Cont'd) Number 6.7 6.8 6.9 Estimated Asbestos Emissions from Vehicles Using Rohl et al. (1976) Figures for Asbestos Content of Wear Debris ---- Asbestos Concentration During Automobile and Truck Brake Service Asbestos-Free Composition of a Disc Brake Pad 92 94 97 ~I :l :1 1 l il !~ ~t ;I ' l vii l FMSI 06126 I 1 1 LIST OF FIGURES I Number I 2.1 Schematic Diagram of the Structure of a Chrysotile Fibre Formed of Several Scrolls of Individual Crystallites 3 1 2.2 Schematic Diagram of the Crystal Structure of an Amphibole Fiber, Indicating the Unit Cell Based on x7s18o22 (OH) 2 4 3.1 Asbestos Industry Structures I 3.2 Asbestos Products Industry 19 20 I 4.1 Asbestos - Salient Statistics 4.2 U.S. Asbestos Demand, and Projected Trends to 2000 r 5.1 Possible Areas of Asbestos Deposits 30 48 53 5.2 Asbestos Mines in the United States 54 I 5.3 Quebec Production Trends, From Analysis of 1951 - 1970 Data 57 f 6.1 Geographical Dispersion of U.S. Friction ~~terials Plants 66 t 6.2 Dry-Mixed Brake Lining Manufacturing Operations 69 1il 6.3 Wet-Mixed Molded Brake Lining Manufacturing Operations 71 6.4 Holded Clutch Facings Manufacturing Operations 72 I 6.5 Woven Clutch Facings }~nufacturing Operations 74 I l t l I viii I FMSI 06127 1 I II 1 I i I 1.0 INTRODUCTION This study on the commercial market and environmental sources of asbestos was undertaken for the following reasons: (a) to consolidate the large volume of published literature in an attempt to describe the asbestos industry and the uses of asbestos in terms of marketing data and statistics; and (b) to examine the potential for asbestos emissions from final end-use products. Asbestos emissions from mining and milling operations and from industrial factories have been examined in reasonable detail by previous EPA reports. However, no comprehensive attempt has been made to examine the sources and quantities of asbestos which may be released to the environment from asbestos-containing products. Unfortunately, because of limited funds, this report considers only the asbestos emissions from friction materials such as brake linings and clutches. :,1 : il I '" 1 FMSI 06128 I I 2.0 DESCRIPTION OF ASBESTOS f 2.1 Composition and Properties of Asbestos "Asbestos" is not the name of a distinct mineral species but is a I commerical term applied to fibrous varieties of several minerals differing widely in chemical composition, the fibers being diverse in length, strength, flexibility, and consequent usefulness (The Asbestos Factbook, 1970). The I varieties of asbestos most used commercially are chrysotile, amosite, crocidolite, and anthophyllite. Chrysotile, which accounts for approximately 95% of all asbestos consumed commercially, is of the serpentine group of fibers, while the other varieties (crocidolite, amosite, anthophyllite, tremolite, and actinolite) are of the amphibole group of fibers. Among the amphibole asbestoses, amosite and crocidolite are the most important commercially; anthophyllite, trernolite, and actinolite account for only minor commercial consumption (Kover, 1976; Clifton, 1975). Sometimes the literature refers to the common asbestoses with jargon names: "white asbestos" for chrysotile and "blue asbestos" for crocidolite (Berger and Oesper, 1963). While the asbestoses differ in chemical composition, they share similar polymeric silicate structure. The fibrile-like structures of the asbestoses result from linear chains of silicate tetrahedra. Chrysotile and amphibole asbestoses fundamentally differ by the number and shape of the silicate units. These differences can be visually identified from Figures 2.1 and 2.2, which are structure schematics of chrysotile and amphibole, respectively. Chrysotile consists of Si 2o5 silicate units arranged in double layers and formed into a laminar structure. The chrysotile Si2o5 layers are joined by brucite (magnesium hydroxide) layers. This double layered structure is contorted in 2 FMSI 06129 I I I r I 1 r I t I I I I -!1' ~ Figure 2.1. Schematic Diagram of the Structure of a Chrysotile Fibre Formed "~'- of Several Scrolls of Individual Crystallites (Each scroll is formed from a closely connected double layer having magnesium 'i hydroxide units on its external face and silica units on its i inner face. The details of a small section of the scroll show the structure of the double layer and of the unit cell based on I Mg3(Si20s) (OH) 4.) (Kover, 1976) I ( 3 I FMSI 06130 i I I 1 f l I' I 1 I I I Iii If' ! l'k...._ Figure 2.2. Schematic Diagram of the Crystal Structure of an Amphibole Fiber, Indicating the Unit Cell Based on x7si8o22 (OH) 2 (The line A-A J.. represents the edge of the preferred cleavage plane along which the fibres will split to form even smaller fibres.) (Kover, 1976) ~ t I l li i4 il. FMSI 06131 I I I tubes in which the brucite forms the outer fiber layer. The amphiboles contain I silicate as Si4o11 double chains in a banded structure. The chains are united by intercalcated cations and form as solid fibers (Berger and Oesper, 1963; Badolette, 1963; Kover, 1976). Unlike the synthetic chemicals which usually exhibit unique chemical compositions, the asbestoses are composed of mixed inorganic oxides. The various asbestoses are characterized by ranges of these oxides rather than precise molecular formulas. Table 2.1 below gives the approximate chemical formula for l each of the varieties of asbestos, while Table 2.2 lists the typical ranges of mixed oxide compositions for the asbestoses and a few related minerals. Table 2.1. Approximate Chemical Formula of the Asbestoses (The Asbestos Factbook, 1970) Chrysotile 3MgO 2Si02 2H 2o Crocidolite Na2o Fe2o3 3Fe0 8Sio2 H20 Amosite l.SMgO 5.5Fe0 8Si02 H20 Anthophyllite 7Mg0 8Si02 H20 Tremolite 2Ca0 5Hg0 8Sio2 H2o Actinolite 2Ca0 4Mg0 FeO 8Si02 H20 1 Since asbestos is a metamorphic mineral, its composition reflects the composi- 1 tion of the su'rrounding minerals and its formation conditions. Therefore, the l oxide composition range differs for asbestoses of different geographical origin, as evident from Table 2.3. The asbestoses contain relatively few elements. In l 5 ] FMSI 06132 - - - -'"~'~ ~;s;,~) ~ ~ """"'"""" ~'-'! ~"'"""''Q f';so;.~ .~ -""~~~-....-- ~ Table 2.2. Chemical Composition of Common Fibrous Silicate Minerals (Kover, 1976) Typical ranges, wt-% SiOz MgO FeO Fe2o3 Alzo3 CaO K2o Na2o H2o Chrysotile 38-44 40-43 0-0.8 0.5-4 0.3-0.9 0-1.0 Trace Trace 13-14 Crocidolite 49-53 0-3 13-20 17-20 0-0.2 0.3-2.7 0-0.4 4-8.5 2.5-4.5 Amosite 49-53 1-7 '34-44 ----- ----- ------- 0-0.4 Trace 2.5-4.5 0\ Anthophyllite 56-58 28-34 3-12 ----- 0. 5-1.5 ------- ----- ------- 1-6 Actinolite 51-56 15-20 5-15 0-3 1.5-3 10-12 0-0.5 0.5-1.5 1. 5-2.5 Tremolite Talc 55-60 60-63 21-26 30-32 0-4 0.6-2.5 0-0.5 0-1.5 0-2.5 0-2.5 11-13 0-1.4 0-0.6 ----- 0-1.5 0.5-2.5 ------- 0-0.3 Hornblende 39-54 3-25 0.2-23 0-9 4-15 9-13 0-1.7 0.5-4.3 0-2.6 Orthopyroxene 44-60 4-39 3.5-48 0-3 0-8 0.2-4.2 0-0.6 0-0.9 0-0.8 , --3en: e0n ww 1II I r I I I I I 1 t i !l l addition to silicate and water, they generally contain the oxides of magnesium, calcium, iron, and/or sodium. Aluminum and potassium oxides are sometimes present as trace "impurities." The "impurities" are defined as the oxides which are not accounted in the approximate chemical composition. They can either form part of the polymeric structure or occur as occlusions within the fibers (Berger and Oesper, 1963). Table 2.4 describes some of the properties important in the commercial uses of asbestos. The properties of asbestos that give it commercial value are its fibrous structure, the great strength of its fibers, and its resistance to high temperatures and to certain types of chemical attack. Chrysotile asbestos excels commercially due to its fineness of fiber, high flexibility, good heat resistance, general workability, and ample supply. The longer fibers can be spun easily into textile materials. However, chrysotile degrades faster than the amphiboles in water, acids, or alkalis. This results from the solubility and reactivity of the brucite. While amphiboles lose only ~ 9% of their weight in 4N HCl after eight hours at 100C, chrysotile looses all magnesium hydroxide (60% of its weight) after only one hour in 1 N HCl at 95C (Berger and Desper, 1963). When chrysotile is extracted by the Soxhlet procedure for four hours with aqueous alkali (pH 10.33), it loses a high percentage of magnesium ion and yields magnesium silicate. Crocidolite, when treated by the same conditions, will leach only 4% silica and 6% sodium (Berger and Desper, 1963). Because crocidolite and amosite fibers are highly acidresistant, they are particularly valuable for use in chemical plant applications. Anthophyllite and tremolite fibers are too brittle to be spun or used as fibrous reinforcements but, because of their resistance to attack by certain chemicals, are used for filtering purposes in chemical processing plants and in laboratories. 7 FMS\ 06134 r:~~ ~ ~ "'~ ~~~ ~) ~~I ~~ ~ -/;11 ~ ~ ~ ~ ~ ~ - -- - Table 2. 3. Chemical Composition of Asbestoses from Different Geographic Locations (The Asbestos Factbook, 1970) co , s: (JJ 0 .0...). e(onJ Variety and Location FeO Si02 (Ferrous (Silica) Oxide) orFe 2 (Fen c Oxide) HnO (AAlulm2oin3a) HgO (Magnesia) cao (Lime) (M:lngFJnese Oxide) oNa 2 (Sodium Oxide) K2o Ht- (Potassium (Com ined Oxide) \later) HzO+ (Combined Water) Chrysotile (Quebec) 40.2 1.0 0.5 2. 9 39.9 1.1 0.1 0.1 0.1 0.8 13.4 Chrysotile (So. Rhodesia) 39.7 0.7 0.3 3.2 40.3 1.1 0.3 0.1 0.1 0.6 12.2 Chrysotile (Ural Hts.) 38.1 1.3 l.ll s.o 37.7 2.2 0.1 0.1 0.1 0.8 11.1 Crocidolite (Cnpe Province) ~0.9 20.5 16.9 nil 1.1 1.5 0.1 6.2 0.2 0. 2 2.2 Crocidolitc (Australia) 52.8 1'. 9 18.6 0.2 4.6 1.1 Trace 6.0 0.1 0.2 2.8 Cwcidolite (Bolivia) 55.7 3. 8 13.0 4.0 13.1 1.5 Trnce 6.9 0.4 Trace 1.8 Amosite (Transvaal) 49.4 40.6 0.1 nil 6.7 0.7 0. 7 0.1 0.2 0.1 1.9 Anlhophyllite (Finland) 59.1 6.7 1.0 0.9 29.7 0.1 0.2 0,1 0.1 o.s 2.4 Trernolite (Pakt.tan) 55.1 2.0 0.3 1.1 25.7 11.5 0.1 0.3 0.2 3.5 0.2 Actinolite (Cape Province) 53.8 25.3 2.0 1.2 4.3 10.2 0.4 0.4 0.1 0.2 2.6 1I I :f 1t i .. i Table 2.4. Physical, Chemical, and 'Hineralogical Properties of Varieties of Asbestos (Kover, 1976) Property Chem.cal formula p>l Chrysotile Mg3Si 20 510Hl4 Crocidolite Amosite Anthophyli,:e TremoUte Actinolite Na2Fe3Si80 2 2(0H) 2 (f'eMg) 7Si 80 2 2tOHi 2 iFeMgi 1S1 80 2 20HJ 2 Ca2Mg3Si80 2 2 tOH) 2 (CaMgFe) 5Si80 2 2(0Hl 2 9 2to 98 -- ----- N<tu!ral -- R~'l,stance to ectds P001 Good -- -- Good Good Vrn"'11 CttaJ and slip titn Croosfiw Vou fibet SliP. rN!ll f,b._.r unori~nted and int!rlacing Slip or rnau f&b,.r Slip Of mauti~e-r Color Gretn, g;ay. mber lo white 81~ 'Gray, yeiJ::ww to dark brown YPIIownh brown, gt3yi\.h VIA"!tre Grav-whtte. greeniih. yellowish. blui ..!l Gre-enish Texture Soft to horsh. ol.o ,;n,v Soli tohorh luster Sil~y Sotl<y to dull Hardness3 2.Sto 4.0 4 Coarsa but somewhat ph able V1treous. 1omeowhJt pearly 5.Sto 6.0 Hanh Vitreous to pearty 5.5 to 6.0 G~nerally harsh. somf'tmeos \Oft Solky 5.5 H;,nh Silky 6! Flexibility SIJinnability Hog, Vt!ry g>od Gcod Fatr Good Fair Poor Poor Poa< Poor Poor Poor Tensile strength. lb_ in. 2 824.000 '" 876.000 , . 16.000 to 90,000 4.000 and IPU 1.000to 8.000 1,000 anU It~') Fusion point,F 2.710 2.180 2.550 2,675 2.400 2.540 Specific heat, Btullb.F 0.266 0.201 0.193 0.210 0.212 0.217 ~orking Scale of Hardness: 1 - very easily scratched by fingernail, and has greasy feel to the hand; 2 - easily scratched by fingernail; 3 - scratch by brass pin or copper coin; 4 - easily scratched by knife; 5 - scratch with difficulty with knife; 6 - easily scratched by file; 7 - little touched by file, but will scratch window glass. All harder than 7 will scratch window glass . 9 FMSI 06136 f I Table 2. 4. Physical, Chemical, and Mineralogical Properties of Varieties of Asbestos (Cont'd) I Property Chrysotile Crocidolite Amosite Anthophyllite Tremolite Actinolite r Electric charge Positive NtQtti.,. Negative Ntgoti-n Negative N1911i. . Filtration Slow Foot hot ffldium Mediun~ Modiunt l properties Specific 2.4to 2.6 3.2to 3.3 3.1 IO 3.25 2.85 to 3.1 2.9to 3.2 3.0 to 3.2 gravity I Cleavage 010 perfect 110perfoct 110perfect 110 perfect 110perfect 110 perfect Optical properties Biaxial positive, U)Ctinction parallel Refractive index 1.50ta 1.55 Resistance to destruction by heat Good, brittle at high temperatures Temperature at ignition loss,F 1,800 Magnetic content,% Crystal structure O.Oto 5.0 Fibrous and asbestiform Biaxial extinction inclined 1.7 pleoc:htoic Poor. fuses 1,200 Biaxial positive, extinction parallel aia.aaf 1)06itiv. extrnetion poullol 8ioxill negotivo. extinction inclined Biaxial negative, extinction inclined 1.64~ 1.61t Good, brinlo II ~il> t~r4turts 1,600 to 1,900 Very good 1,SOO 1.61t 1.63t we1kly pleochroic Fair togaed -- --1,800 3.01o 5.9 Fibrous 0 Prismatic, lamellar to fibrOUI 0 Prdmatic., lamellar to fibrous 0 Long ond thin eotumn1r to fibrous -- Long and thin colum"ar to fibrout Crystal Monoclinic and Monodinlc Monoclinic OrthO<hombie MonodirtH: Monoctinc system orthorhombic -- - -1-- - ---- I. Mineralogical In veins of Fibrous in Lamellar. Lamellar. lony, plllomiltiC Rtillcyclotl structure serpentine. etc. iron stones coarse to fibrous and fibrous long prismatic line fibrous asbestiform aggregatet crystals and and asbestiform fibers Mineral association In altered peridotite adjacent to serpentine and limestone near contact with basic igneous rocks Iron rich si1icious argillite in quartzose schists In crystalline schists, etc. In crystalline schists and gneisses In Mg limestones as alteration product of magnesian rocks, metamorphic and igneous rocks In limestones and in crystalline schists 10 FMSI 06137 I I { Since asbestos is often used in the manufacture of insulation for electrical equipment, its electrical conductance is an important property. I Its conductance is related to the magnetite (Fe304) content. As the content I of this impurity increases, the asbestos conductance also increases (Berger and Oesper, 1963). I The thermal stability is limited by asbestos metamorphosis to other mineral forms. The fusion points listed in Table 2.4 are not melting points I for the asbestoses, but correspond to the fusion temperature of the metamorphic r products. Chrysotile, for example, is thermally transformed to the minerals olivine or enstatite at a rate dependent upon time and temperature. The trans- ( formation may be important to assess some environmental losses for certain uses, such as in brake linings (Berger and Oesper, 1963). I 2.2 Asbestos Grading [ Asbestos is graded by fiber length. It is not commonly graded by mineralogical content or other properties. The Quebec Standard for chrysotile is the most important, because most asbestos consumed in the U.S. is graded by this system. The Quebec Standard measures the distribution of fibers after sieving a 16 ounce sample through a system constructed of fotlr boxes: three screens and a "pan" for fines: Box Number Screen Opening Diameter of Wire 1 0.500" 0.105" 2 0.187 11 0.063" (4 mesh) 3 0.053" 0.047 11 (10 mesh) Asbestos fibers are graded in nine groups: Groups No. 1 and 2 are hand-cobbled crudes and the remainder are milled fibers. Group No. 1 is basically 3/4" staple and longer fibers, which makes the best spinning grade. Group No. 2 includes 11 FMSI 06138 l [ spinning fibers of lower quality. The milled fibers are grouped according to I the box distributions listed in Table 2.5 (Berger and Oesper, 1963; The Asbestos F'actbook, 1970). l Other grading systems are also used for chrysotile and the amphibole asbestoses. They also grade fibers by length. U.S. mined asbestos basically [ follows the Quebec Standard. Table 2.6 describes the modifications used for r Arizona and California mined asbestos. ... 2.3 Major Uses of the Asbestoses ( The following discussion briefly describes the major uses for the asbestoses and the reasons why they are used. }1arket input/output data concerning the quantities consumed according to use and grade are given in Section l1. 0. 2.3.1 Chrysotile Chrysotile dominates the asbestos consumed in total quantity, value, and number of products. It accounts for about 95% of all the asbestos commercially consumed. (a) Asbestos Textiles The long chrysotile fibers (Grades No. 1, 2, and 3) are predominantly used for textile manufacture. The textile products can eventually be marketed as textiles such as safety clothing, drapes and curtains, wicks, etc. or they can be further processed with resins and other additives in the manufacture of friction materials, gaskets, laminated plastics, etc. (Kover, 1976; Hendry, 1965; The Asbestos Factbook, 1970; Clifton, 1975). (b) Asbestos Cement Medium sized chrysotile fiber (Groups No. 4 to 7) dominate I in production of asbestos cement products (pipe and sheet). Asbestos cement l 12 FMSI 06139 I l [ Table 2.5. Chrysotile Grades by the Quebec Standard Test (The Asbestos Factbook, 1970) [ Standard Grade Designation ( Group No. 1, Crude No. 1 ( Group No. 2, Crude No. 2 I Group No. 2, Crude run-of-mine r Group No. 2, Crudes sundry I Groups No. 3 through No. 9 Fiber Description - consists basically of crude 3/4" staple and longer - consists basically of crude 3/8" staple up to 3/4" - consists basically of unsorted crudes - consists of crudes other than above specified - are ""t-lilled Asbestos" Guaranteed Minimum Shipping Test (Distribution of 16 oz. of Fibers) Iff Box 1 Box 2 Box 3 Pan (fines) r Group No. 3: 3F 10.5 3.9 1.3 3K 7.0 7.0 1.5 3R 4.0 7.0 4.0 3T 2.0 8.0 4.0 3Z 1.0 9.0 4.0 0.3 0.5 1.0 2.0 2.0 Group No. 4: 4A 0.0 8.0 6.0 I 4D 0.0 7.0 6.0 4H 0.0 5.0 8.0 4J 0.0 5.0 7.0 ! 4K 0.0 4.0 9.0 4M 0.0 4.0 8.0 4R 0.0 3.0 9.0 4T 0.0 2.0 10.0 4Z 0.0 1.5 9.5 2.0 3.0 3.0 4.0 3.0 4.0 4.0 4.0 5.0 Group No. 5 SD 0.0 0.5 10.5 { 5K 0.0 0.0 12.0 5M 0.0 0.0 11.0 SR 0.0 0.0 10.0 !I sz 0.0 0.0 8.6 ! 5.0 4.0 5.0 6.0 7.4 I 13 FMSI 06140 l l [ Table 2.5. Chrysotile Grades by the Quehec Standard Test (Cont'd) l { ( Group No. 6 Group No. 7 l r [ Group No. 8 [ Group No. 9 Box 1 Box 2 Box 3 Pan (fines) 6D 0.0 0.0 7.0 9.0 7D 0.0 0.0 5.0 7F o.o 0.0 4.0 7H o.o 0.0 3.0 7K 7M o.o 0.0 2.0 o.o o.o 1.0 7R 7T 0.0 o.o 0.0 0.0 0.0 o.o 7W 0.0 0.0 0.0 11.0 12.0 13.0 14.0 15.0 16.0 16 .o 16.0 8S under so 1bs/cubic foot loose measure 8T under 76 lbs/cubic foot loose measure 9T over 75 lbs/cubic foot loose measure I l I 14 FMSI 06141 I I I I ( I I I l Table 2.6. Modifications in Grading American Mined Asbestos (The Asbestos Factbook, 1970) ASBESTOS GRADES IN ARIZONA Source: Metate Asbestos Corporation, Globe, Arizona Th~ sanl~ "Guaranttcd Mmimum Shipping Tests" arc us~d in Ari1.011~ as arc used in Canada. with the follmving "'"'-'ptlons: 3Z (Soft Filt~r GraJe) is hdd to - 0 10 4 Special Sugar Grade LX-222-NAW is held to about Can~dian GDdc 3T 2 8 4 2 All other Arizona Grade~ follow Canadian grading procedures but add the following design at ions: s H AW NAW Soft -Harsh Acid Wa>h~d - Non-Acid Washed ASBESTOS GRADES IN CALIFORNIA Source: Coalinga Asbestos Company, Inc., Coalinga, California The following o;hort Chrysouk asbestos fiber gradts arc available from Johns-Manville Corporation\ C0alinga Mine at Coalinga. Califurnia. While the chemical cumpmition Chry>otik. they arc ty pokfaCllaj'lilfio~rhnticarnI l l l ibns colo r is very ,lowcr similar in lines to that content of Canadian and higher in \urfacc area. U/. TRABJ-:STOS Red /;iraml a hit:h 'urfacc area. high absorption, low tines gcncralpurpo'c short tibtr. Ul. TRAB/:STOS Blue Brand a l11gh quality. low tines sh rt fiber somewhat similar to Canadian Grade 7 R This Grade is prepared e> lccially for us.: in vinyl 11oor tile. Coalin~:a Float.> approximately an 9S';i. cbxylrtchme~l~y!cN,icJtolrl t~f'itb.er(Sheacvipnaggea minus 2l 23 for a 0 mesh cont'-'n description of Lof this tc;t.) Coalin);a /'apcrn<"stml {)(!: an extremely ,fwrt nhcr prcpurcd rur usc in the p~pcrmakint: industry as <I pttch cuntrnl and pt)::III1.'11L rc!l"tllion aiLI. Crwliu~:a ,!Jhaltic '' llh'tlllllll ah"HPIIIlll sholl nhcr lor asph;Jil paving applitallon>. 15 FMSI 06142 [ I products account for the major portion of the asbestos consumption, both in I tonnage of fiber and market value. The properties which contribute to its commercial position include fiber length and tensile strength (Kover, 1976; I Carton, 1974; Berger and Oesper, 1963; Clifton, 1976). (c) Asbestos Paper and Felt I Properties for which chrysotile is used in this product segment I include its capacity for heat and electrical insulation, its chemical and thermal stab.ility, its strength and flexibility (Kover, 1975; Carton, 1974; Hendry, 1965). Chrysotile grades from 3 to 7 are predominantly used (Berger and Oesper, 1963; Clifton, 1975). [ (d) Composition Materials I The composition materials include plastics, asbestos-vinyl and asbestos-asphalt products, coatings, and compounds. Chrysotile is added to l these products generally as a filler and reinforcement medium (Modic and Barsness, 1965; Seymour, 1968; Grove and Rosato, 1967). The longer fibers (including ( Grades No. 1 and 2) are used in the production of high grade laminated plastics. The short fibers (Grades No. 4 and shorter) dominate in the manufacture of most other composition materials (Clifton, 1975; Berger and Oesper, 1963). Although the quantity of fibers used in these products is large (the second largest consumption of fibers), the low value of the short fibers results in a low commercial value for asbestos used in this market segment. (e) Friction Materials The properties for which asbestos is used in friction materials include its capacity for thermal stability, its ability to act as a reinforcing agent, as a filler, for the regulation or inhibition of resin flow, its lower ( tl. 16 FMSI 06143 I ( ( abrasion than other fillers of its price range, and its dispersion of metal chips and other particulates (Hendry, 1965). While the fiber lengths of Grades ( No. 4 to 7 dominate the friction materials, some longer fibers are also used l (Clifton, 1975). (f) Packing and Gaskets I Chrysotile use in packings and gaskets is accounted for by its strength, resiliency, durability, toughness, and thermal stability (Hendry, I 1965; Kover, 1976). Fiber length predominantly ranges from Grades No. 4 to 7, although some Grades 1 through 3 are also consumed (Clifton, 1975; Berger and Oesper, 1963; SRI, 1974). l 2.3.2 Crocidolite Crocido1ite fibers are shorter and more brittle than chrysotile but have a slightly higher tensile strength. Crocidolite is principally con- I sumed for the manufacture of asbestos cement products (Kover, 1976; Clifton, 1976). While it can be spun into fibers, its spinnability is not equivalent to chrysotile. Longer crocidolite fibers are sometimes mixed with chrysotile for textile production (Berger and O~sper, 1963). It is used as replacement for chrysotile fibers in some laggings, insulations, filter media, and packings exposed to corrosive (acid or alkali) substances (Fisher, 1967; Hendry, 1965; Kover, 1976). Long crocidolite fibers are also consumed in asbestos boards and papers (Berger and Oesper, 1963). 2.3.3 Amosite J'.i-,i Amosite has lower tensile strength than chrysotile or crocidolite by more than an order of magnitude. It is consumed mainly in asbestos cement products. Other major uses are in various thermal insulations, including pipe and boiler coverings, bulkhead linings in ships, and 85% magnesia insulation (Hendry, 1965; Kover, 1976). 17 FMSI 06144 [ ( 2.3.4 Tremolite and Actinolite Both tremolite and actinolite are of low tensile strength and [ are brittle. They have only minor commercial use. They are primarily con- ( sumed as cheap fillers and as filtering mediums. Tremolite is sometimes purified by acid treatment for special filtering purposes (Kover, 1976; Hendry, 1965). l 2.3.5 Anthophyllite Anthophyllite is also of minor commercial value. It is mainly I used as a filler in rubber, plastics, adhesives, and asbestos cement products [ (Kover, 1976; Hendry, 1965; Clifton, 1975). l [ I [ [ [ 18 FMSI 06145 I [ 1 3.0 DESCRIPTION OF THE ASBESTOS INDUSTRY 3.1 Industry Structure r Figure 3.1 below is a simple illustration showing the movement of 1 asbestos within the asbestos industry. ( Mining --- Hilling ---+Primary Secondary ~Consumer r Industries Industries Industries { Lconsumer Industries Figure 3.1. Asbestos Industry Structure I The following definitions have been adopted (Daly ~tal., 1976): J'rimary Industries: those industries that start the manufacturing process with I raw asbestos fiber and modify the fiber to produce an intermediate product (to be further processed or fabricated) or a finished product. Secondary Industries: those industries that continue the manufacturing process I with an intermediate asbestos product (one in tvhich the fiber has previously been modified in a primary industry), and further process, modify, or fabricate it to produce either another intermediate product (to be further processed or fabricated) or a finished product. Consumer Industries: those industries that purchase a finished asbestoscontaining product (from a primary or secondary industry), and apply, install, erect, or consume the asbestos-containing product without further physical I modification of the product. This classification is depicted in Figure 3.2, which categorizes the I jj various end uses by products. 19 FMSI 06146 .-~1.~">1 ~CIFfA..ll' - - - - t- - -- -ll"~'-1 !IM'"""'' ,._ ~~ --~ -- --... N 0 "T1 3: ~ 0 Q) ~ ~ Primary Industries FLOOR TILE GASKETS & PACKINGS FRICTION PRODUCTS PAINTS, COAT1 NGS & SEALANTS ASBESTOSREINFORCED PLASTICS ASBESTOS CEMENT PIPE ASBESTOS TEXTILES ASBESTOS PAPER ASBESTOS CEMENT SHEET MISCELLANEOUS Secondary Industries OfFICE. HOME, C MMERCIAL FLOORS VALVE. HANCE 'UMP, TANK S[ALING COMPON[NTS CLUTCH/TRANSM SSION, DRAKE COMPONENTS INDUSTRIAL FR fiON MA TERI/\LS AUTOMOTIVE/T JCK OOOY COATINGS noor COA liNGS ~Nil PATCtllNO COMPOUNDS ELECTRIC MOTO COMPONENlS MOLDED POOOU 'COMPOUNDS FOR ttiGit STRENGTHh'Vf.IGilT USES CHEMICAL PROC :S PIPING WATER SUPPLY P 'lNG CONDUITS FOR E ECTRICAL WIRES PACKING COMPO lENTS GASKET COMPOI'. :NTS ROOFING MA TEA ALS COMMERCIAl/IN 1USTRIAL DRYING FELTS HEATIFIRE PROl :CliVE CLOTHING CLUTCH/TRANSM SSION COMPONENTS ELECTRICAL WIR : AND PIPE INSULATION THEATER CURTA NSAND FIREPROOF DRAPERIES CASIV APOA DUC S fOtl CORROSIVE COMPOUNDS FIREPROOF AbSO =tBENT PAPERS TABLE PADS AND Hf.AT PROTECTIVE MATS HEAT/FIRE PROT :CTION COMPONENTS MOL TEN GLASS t- 1\NDLING EQUIPMENT INSULATION PROI )UCTS GAS9C.ET COMPON :NTS UNOERLAYMENT FOR SHEET FLOORING ELECTRIC WIRE sULAfiON Fll TEAS FOR tiE ERAGES APPLIANCE INSU A,TION ROOFING MATEA ALS HOODS, VENTS F 'R CORROSIVE CHEMICALS CHEMICAL TANK AND VESSEL MANUFACTURING PORTABLE CONS RUCTION 8UILOINGS ELECTRICAL SWI "CHBOARDS AND COMPONENTS RSIDE.N11AL BU LOING MA,l[RIALS MOL TEN METAL lAND LING EQUIPMENT INDUSTRIAL SUI DING MATERIALS FIRE PAOTECTIO' I INSULATION PRO )UCTS SMALLI\PPUANC E COMPONENTS ELECTRICAL MOl OR COMPONHIHS li\BOnATORY fU RNITUA COOLING TOWER COMPONENTS WHOLESALERS Consumer Industries ARCOEFLECl ORS. ELECTRICAL RESISTANCE SUPPORTS. WATER SUPPLY AND! EWAGE PIPING. DECORATIVE BUILDING PANELS, PLASTER ANO STUCCO, MOLDED PLASTICS, ACOUSTICAL PRODUCTS, SAPHALTPAV NG. CAULKING, MOTOR ARMATURES, PAINTS. AMMUNITION WADDING, WELDING-ROO COATINGS, DRIP CLOTHS, FIRE ODORS., IUTOMOTIVE BRAKES AND TRANSMISSIONS, HEATER ELE~ ENT SUPPORTS. OVEN AND STOVE INSULATION. SIDING SHING .ES, AUTOMOTIVE GASKETS, ELECTRIC MOTOR CASINGS. ELE :TROLYTIC CELL DIAPHRAGMS, FLOOR Tl LES, SPACEVEHICI E HEAT SHIELDS, CORROSIVE-RESISTANT PIPING ANDOUCTS,M ~RINE BULKHEADS, TANKS FOR CHEMICALS. FIRE HOSES. ( ARMENTS. GLOVES, FILTEA MEDIA. AUTOMOTIVE UNDERCOATINGS, BOILER INSULATION, FURNITURE, PUMP AND VA VE SEALS, MOTION PICTURE SCREENS, ROOFING PRODUCTS. M! LTENMETAL CONVEYORS, RUGS, WALLBOARD. POWER-CABL! NSULATION, ELECTRICAL SWITCHES Figure 3. 2. Asbestos Products Industry (Daly ~ al., 1976) l 1 I The first industry segment to come into contact with the asbestos is, t of course, the mining segment. As far as the United States is concerned, however, this predominately occurs in Canada. From 1971 to 1975, between 80-85% of l the asbestos consumed domestically was imported (see Sections 4.3 and 4.4); and of the imported asbestos, nearly 96% originated in Canada (Clifton, 1975). The milling segment of the industry is very closely c-:mnected to the mining segment because mills are usually located in close geographical proximity to the mines I and, in general, the mines and mills are omed and operated by the same parent I corporation. ~~erican mining and milling production is discussed in Section 5.1. The interesting relationship is, however, the relationship between the I mining segment of the industry and the primary industries, the product manu- t facturers who initially fabricate asbestos products. Table 3.1 lists the captive fiber sources in Canada and in the U.S. for the major domestic asbestos I products manufacturing firms. ~enty of the largest U.S. asbestos products manufacturers are listed in Table 3.2. \~en Tables 3.1 and 3.2 are compared, it can be seen that four corporations (Johns-Hanville, Raybestos-Manhattan, Jim I.Jalter, and ASARCO) not only control large mining interests in Canada, but also control nearly 35% of the American asbestos products market. According to the 1967 U.S. Census of Hanufacturers, 81 firms operating 138 establishments were involved ln asbestos products manufacturing (SIC 3292; this does not include asbestos paper-making establishments). The 1972 Census of Nanufacturers lists 142 establishments for SIC 3292. When the asbestos paper- i makers are included, it is estimated that approximately 85 firms are presently engaged in asbestos products manufacture (SRC estimate). In evaluating the asbestos products manufacturing industry, it is possible to arrive at the 21 FMSI 06148 I t t Table 3.1. Captive Fiber Sources for the Major American Asbestos Product Manufacturing Firms (Igwe, 1974; Asbestos Magazine, Dec. 1975) 1 1 Company Canadian Hines Mine (Company) Fiber-Producing Capacity (short tons/year) 1 ASARCO Johns-Hanville l Products Corp. Jim Walter Corp. Lake Asbestos of Quebec, Ltd. Canadian Johns-Manville Co., Ltd. Carey-Canadian Mines, Ltd. Raybestos-Manhattan, Inc. Cassiar Asbestos Corp. (partial interest) General Dynamics Corp. Asbestos Corp., Ltd. (54% interest) 150,000 835,000 200,000 110,000 500,000 American Mines I Atlas Asbestos Co. Union Carbide Corp. Atlas Asbestos Co. Union Carbide Mines l Johns-Hanville Products Corp. Coalings Asbestos Co. 25,000 10,000 (closed at present) l 1 II 22 l FMSI 06149 1 l Table 3.2. Twenty of the Largest U.S. Asbestos Product Manufacturers (Economic Information Systems, 1976; Igwe, 1974; SRC Estimates) 1 Estimated 1975 Asbestos-Product Sales Approximate Percentage I Company ($ millions) of the U.S. Market 1 1. Johns-Manville Corp. 2. Raybestos-Manhattan, Inc. l 3. GAF Corp. 4. Bendix Corp. .I 5. Jim Halter Corp. (Celotex) l 6. Armstrong Cork Co. I 7. Illinois Central Industries (Abex Corp.) 8. Flintkote Co. [ 9. Asten-Hill Mfg. Co. 240 140 114 72.5 71 60 60 so 40.5 18.0 10.5 8.5 5.5 5.5 4.5 4.5 3.5 3.0 I 10. H.K. Porter Co. 11. Certain-Teed Corp. l 12. Nicolet Industries 13. Kentile Floors Inc. l 14. National Gypsum Co. 37.6 33.1 30.7 29.5 27.1 3.0 2.5 2.0 2.0 2.0 J 15. Royal Industries li 16. Uvalde-Rock-Asphalt Co. 24.5 21.6 I 17. Sabine Industries 21.6 18. American Asbestos Textile 15.0 l"' 19. ASARCO Inc. (Cement Asbestos Products) 13.0 l 20. Gatke Corp. 11.6 2.0 1.5 1.5 1.0 1.0 1.0 J 23 I FMSI 06150 1 conclusion that the industry may be dominated by several giant firms. From Table 3.2 it can be seen that the six largest firms control over SO% of the l market. It should also be noted that the larger asbestos-based manufacturing l firms are generally diversified into other product lines. Table 3.3 shows the percentage of some major manufacturers' product lines that are related to f asbestos. l Table 3.3. Asbestos-Based Activity of Some Major Asbestos-Manufacturing Companies (Igwe, 1974; SRC Estimates) 1 I Company Estimated Annual Sales ($ millions) Percent of Product Line Related to Asbestos American Biltrite Rubber Co. The Flintkote Co. GAF Corp. 1 Johns-~mnville Corp. National Gypsum Co. t Jim Walter Corp. 161 441 800 519 880 5 12 5 30 5 8 1 3.2 Types of Plants I Asbestos products manufacturing plants are characterized by a high degree of specialization. The typical plant (especially of the minor manufac- 1 turers) is apt to be a single-product operation whose product is geared to service a specific industry. Table 3.4 lists the general statistics for 24 FMSI 06151 I 1 l Table 3.4. Industry Specialization and Primary Product Class Specialization for Asbestos Product Producing Establishments: 1972 (SIC 3292) (1972 l Census of Manufacturers, U.S. Bureau of the Census) t 1 Entire Industry Establishments Establishments with 75% or More Specialization 142 127 Primary Product Class Friction Materials l Asbestos-Cement Shingles and Clapboard [ Vinyl Asbestos Floor Tile 23 7 18 21 6 17 Asbestos and Asbestos-Cement Products 55 42 l establishment specialization in 1972. In Table 3.4 the measures of plant specialization are shown as: (1) industry specialization - the ratio of primary product shipments to total product shipments (primary plus secondary) and (2) product class specialization - the ratio of the largest primary product class shipments to total product shipments (primary plus secondary) for the establishment. l A survey of selected facilities shows that nearly all the large plants employing in excess of 100 workers belong to the major firms within the industry, such facilities also often generating relatively minor proportions of nonasbestos products (Igwe, 1974). 25 1 FMSI 06152 i i 1 l l I t t 1 l ~ I l 1 l I l 1 l 1 11 It is fair to state that the asbestos manufacturing industry in the United States is very mature, with most of the larger plants well over 25 years old and employing well-established technologies. For instance, asbestos-cement pipe manufacture was introduced in the United States about 1928 by the JohnsManville Corporation at its Waukegan, Illinois, plant. Except for incorporation of sophisticated controls and materials handling systems, it is doubtful whether the technology, similar in principle to that employed in the manufacture of flat or corrugated sheeting, has changed to any fundamental extent since then. Similar comments may be applied to the manufacture of vinyl asbestos tiles (Igwe, 1974). 3.3 Numerical and Percentage Distribution of Plants, Employees, and Production The numerical distribution of the establishments by size (expressed in terms of the number of employees) as given by the 1972 Census of Manufacturers is shown in Table 3.5. Total employment as a function of establishment size and total value of shipments as a function of establishment size for asbestos products manufacturing are given in Tables 3.6 and 3.7, respectively. A comparison of Tables 3.5 and 3.6 shows that whereas establishments with less than 100 employees account for 53.4% of the number of asbestos products manufacturing establishments, these facilities employ only 7.8% of the work force. The relative minor contributions of the "less-than-100-employees" facilities are further illustrated when Table 3.5 is compared to Table 3.7. The industry segment with less than 100 employees per establishment contributes only 6.1% of the shipment values of asbestos products. The economic punch nppea n; clearly to rest with the major manufacturing units. There is the additional consideration that, for a given asbestos product, the manufacturing equipment tends to be of a given standard capacity. 26 FMSI 06153 1 Table. 3.5. Asbestos Products Nanufacture: Distribution of Plant Sizes (1972 Census of Hanufacturers (SIC 3292), U.S. Bureau of the Census) it Average Number of Employees Total Number of Establishments Percent of Total 1 to 4 5 to 9 10 to 19 20 to 49 50 to 99 100 to 249 250 to 499 500 to 999 1000 to 2499 Total 12 20 13 16 15 40 19 5 2 142 8.5 14.0 9.1 11.3 10.5 28.2 13.4 3.5 1.4 l I " Table 3. 6. Asbestos Products Hanufacturing: Total Employment as a Function of Size of Facilities (1972 Census of Hanufacturers (SIC 3292), U.S. Bureau of the Census) Average Number of Employees 1 to 4 II ~. I~ 5 to 9 10 to 19 20 to 48 50 to 99 100 to 249 250 to 499 500 to 999 1000 to 2499 Total - * SRC Estimates Total Number of Establishments 40~ 100 200 500 1,100 6,400 6,300 6,300 ....!!,200* 25,140 Percent of Total 0.2 0.4 0.8 2.0 4.4 25.4 25.0 25.0 16.7 27 FMSI 06154 l "Table 3. 7. Asbestos Products Hanufacturing: Total Value of Shipments as a Function of Size of Facilities (1972 Census of Manufacturers (SIC 3292), U.S. Bureau of the Census) I l Average Number of Employees Value of Shipments {$ millions) Percent of Total 1 to 4 5 to 9 10 to 19 20 to ll9 so to 99 100 to 249 1 250 to 499 500 to 999 1000 to 2499 Total I * SRC Estimate l 0.7 4.9 7.4 15.8 30.7 246.8 255.6 '201. 5 200.0* 963.4 0.5 0.8 1.6 3.2 25.6 26.5 20.9 20.8 Differences in plant capacities are therefore determined approximately by the 1 number of installed machines, and capacity diffcrer-.ces therefore occur in m'.llti- 1 ples of one standard machine capacity (Igwe, 1974). J l 1 28 FMSI 06155 I '11 It I 11 l 1! '1 1 4.0 HARKET INPUT/OUTPUT DATA The salient statistics for asbestos are graphed in Figure 4.1, which covers the period from 1940 to 1975. Import and export data shown in Figure 4.1 represent shipments of unmanufactured asbestos only. 4.1 Mine Production Table 4.1 lists the domestic and Horld mine productions from 1965 to 1975. U.S. mines shipped only 75% as much asbestos in 1974 as in 1973 and only 66% as much in 1975 as in 1973. The exact total output of 112,533 tons in 1974 was valued at $13,759,000 (Clifton, 1975). Only four states produce asbestos: California, \lith 53% of the 1974 tot.al, tvas the leader, follm.;ed in order by Vermont, Arizona, and North Carolina. The California segment of the asbestos industry has led the sharp decline in U.S. production. The closing, in early 1974, of Johns-Hanville's (Coalings Asbestos Co.) mine was followed by the closing of H.K.' Porter's (Pacific .Asbestos Corp.) mine. These mine closures led LO production of only 57% of the 1973 California state total, and only 55% of the 1973 dollar value of the fiber was realized (Clifton, 1975). The H.K. Porter mine ,.;as sold in October, 1975, to C:1laveras Asbestos Ltd. and was to begin operation in mid-1976 (Asbestos Magazine, December, 1975). All of the American mines produce the chrysotile variety of asbestos except the North Carolina mines which produce the anthophyllite variety. In total, the American mines produce approximately 15% of the asbestos used in the United States. The remainder is imported, mostly from Canada (see Section 4.3). 29 FMSI 06156 l l 1 1 1 100 1 DOMESTIC PRODUCTION EXPORTS 1 1 1LULLULUULLlu~~JJ~JJJJ~~~~~~~~~~~~~ 1940 1945 1950 1955 1960 1965 1970 1975 1980 1985 1990 Figure 4.1. Asbestos - Salient Statistics (SRI, 1974; Clifton, 1974; U.S. Bureau 1 of the Census, 1975 a, b) 30 FMS\ 06157 ,_,_ - - - - - --~ ,._......., ~ ~ If,~ ~ v-..... ...r- ~ ~ ~ --~~~h-.~~~---- ~ Table 4.1. Mine Production of Asbestos (Clifton, 1975; Asbestos Magazine, December, 1975) (Thousand short tons) 1965 1966 1967 1968 1969 1970 1971 1972 1913 1974 1975 -------- World mine production: United States 118 126 123 121 126 125 131 132 150 11:! 99 w Reb t of uorld 2,934 3,149 3,084 3,170 1;,042 3,672 3,816 1;,050 4 ~4,8 4,42J 4,996 1-' Total 3,102 3, 275 3,207 3,291 4,168 3. 797 3, 94 7 4,182 4, 598 4,536 5,095 -n 3en: -0 0) -Ucol i 4.2 Exports I Table 4. 2 below lists the American export of asbestos (unmanufactured) from 1965 to 1975. f l Table 4.2. U.S. Export of Asbestos (Unmanufactured) for 1965- 1975 (Clifton, 1975; U.S. Bureau of the Census, 1975 b) I Year Asbestos Export in Thousands of Short Tons I 1975 1974 I 1973 1972 1971 1 1970 1969 1968 1967 1966 1965 35 62 66 59 54 47 36 41 /17 47 43 1 Tables 4.3a and 4.3b list the countries to which the exported asbestos (unmanufactured) was shipped in 1975 and in the first half of 1976, respective- 1 ly, and the amounts shipped to each country. Unmanufactured asbestos includes asbestos fibers, not further processed than beaten, washed or graded to length and asbestos waste and refuse. Table 4.4 lists U.S. exports, by country, of i asbestos manufactured products in 1975. In 1975 U.S. exports of unmanufactured asbestos amounted to only 6.5% '~ t of the quantity of U.S. imports, while in 1974 the figure was only 8.1%. On the other hand, the dollar value of U.S. exports of manufactured asbestos prod- ucts was nearly three times higher than the dollar value of U.S. imports of w,J.nufacture.d asbestos products. 32 FMSl 06159 Table 4.3a. U.S. Export --By Country-- of Asbestos (Unmanufactured) in 1975 (U.S. Bureau of the Census, 1975 b) I 2764015 Asbestos fibers, not further processed than beaten, washed, or graded to length Net Quantity Value 1 Canada (Short Tons) 1,567 (Dollars) 682,546 Mexico 6,881 2,349,8L~6 I Brazil Belgium 699 261,080 463 140,181 France 206 204,242 1 \vest Germany Rumania Iran 937 335,709 494 101,420 721 252,817 Singapore 1,137 523,255 Japan 1,334 936' 115 Other Countries 73ll 279,895 Total 15' 173 6,067,106 276~030 Asbestos waste and refuse Canada 3,629 188,856 l1exico 5,109 1,151,572 Colombia 706 124,078 1 Venezuela Brazil United Kingdom 391 70,978 115 67,123 815 131,681 France 458 10l,l!36 West Germany 723 202.087 Italy 120 72,414 Iran 203 78,240 Singapore 615 577,569 Japan 3,842 700,350 Egypt 104 64,558 Other Countries 1,918 460,943 Total 19,748 3,991,885 *U. S. Bureau of the Census, 1975b 33 FMSI 06160 1 Table 4.3b. U.S. Export-- By Country-- of Asbestos (Urunanufactured) from 1 January, 1976, to June, 1976 (U.S. Bureau of the Census, 1976 b) 1 2764015 Asbestos fibers, not further processed than beaten, washed, or graded to length l Net Quantity (Short Tons) Value (Dollars) Canada Mexico t Venezuela Brazil United Kingdom 1 The Netherlands Belgium East Germany Greece l Rumania Iran Thailand l Indonesia Taiwan Japan Algeria Other Countries Total ll48 4,883 119 63 41 298 328 177 126 371 11+0 1,320 900 300 1,532 840 595 12,481 161,298 1,283,987 l+O, 302 41,106 32,000 63,953 76,ll5 130,190 33,840 101,135 39,033 527,987 284,150 116,350 631,900 292,428 1042760 3,960,534 2764030 Asbestos waste and refuse Canada !1exico Colombia Venezuela Brazil United Kingdom I East Germany Spain Italy Rumania United Arab Emirants Korean Republic Japan Algeria Libya Other Countries 1 Total 255 5,430 445 231 378 613 400 120 49 400 192 1,500 3,507 760 149 646 1s,ois 63,389 1,113,082 80,832 36,805 77,447 114,365 209,904 57,831 54,279 76,000 125,195 348,000 546,306 57,054 101,058 158,559 3,220,1.06 l u.}; s. Bureau of the Census, 1976b 34 FMSt 06161 *Table 4.4. u. S. Exports--By Country--of Asbestos l1anufactured Products in 1975 6618310 Asbestos-cement shingles and clapboard Net Quantity (Pounds) Value {Dollars) Canada United Kingdom West Germany Italy Saudi Arabia Japan Other Countries Total 669,126 589,890 17,778,/67 7,205,759 223 '577 2311, 70tl 1,847,108 28,553,931 1Ll2,466 109,149 2,977,698 943,314 78,228 66,185 _331,776 4,648,816 1 6618320 Articles of asbestos-cement or of fiber-cement except asbestos cement shingles and clapboard' Canada 21,936,513 3,867,321 l Mexico Salvador 487' 372 455' 80!+ 138,980 64,879 Panama 5,266,390 715,851 Brazil 134,606 70,184 Sweden 305,303 375,555 \.;'est Germany 102,004 87,175 Iran 265,941 79,733 Saudi Arabia l;,5ll,035 999, 724 Indonesia 33,478 161,793 Phi1ipine Republic 360,441 70,893 1 Japan The Pacific Islands 418,104 320,865 242,323 71,806 Algeria 2,094,038 185,964 1 Republic of South Africa Other Countries 116,300 1,096!502 73,093 ~,60~ Total 37,904,696 7,627,883 'i 6638105 Asbestos gaskets 1 Canada 172,100 500,993 Jamaica 32,955 98,785 Iran 39,551 68,213 Saudi Arabia 91,663 202,404 Republic of South Africa 14,105 79,183 Other Countries 184,962 __Q,,608 Total 535,336 1,610,186 U. S. Bureau of the Census, 1975b l 35 \ FMSI 06162 I Ic:ble 4.4. U. S. Exports--By Country--of Asbestos Hanufactured Products in 1975* (Cont'd) { Net Quantity Value (Pounds) (Dollars) 6638115 Asbestos packing 2 Canada 1,042,869 1,896,802 Mexico Guatemala 393,093 25,828 291,71.;1 68,294 Jamaica 49,803 278,425 Colombia Venezuela 320,649 37,695 513,348 158,526 Surinam 42,645 lf12, 790 Peru 1 Chile Brazil s~veden 151,358 123,234 114,892 15,451 396,141 205,258 119,524 9lf ,047 Finland 30,289 279,984 United Kingdom 264' 110 374,256 Ireland 81,400 366,739 The Netherlands 15,083 113,214 I Belgium France 20,239 41,1.89 139,314 177,591 '.Jest Germany l Switzerland Spain Italy Greece 76,187 17,857 30,531 86,309 25,198 205,023 80,840 183,812 673,373 73,157 I Iran Israel 46,118 9,577 137,128 95,091 Kuwait 16,463 80,943 Saudi Arabia 466,441 256,331 India 145,126 64,691 Pakistan 13,920 64,832 Thailand 42,989 76,663 Singapore 153,4~f8 408' 972 Philippine Republic 229,895 551,008 Korean Republic 27,000 63,030 Taii-lan 52t596 159,405 Japan 57' 871 262,573 Australia 28,394 131,979 J Ne'\o7 Zealand Nigeria Republic of South Africa 25,210 33,470 35,719 170,069 87,997 242,818 Zambia 11,917 118,528 J Other Countries ...,, Total 346!981 tl,749,049 987,008 10,791?265 u. s. Bureau of the Census, 1975b 36 FMSI 06163 I 1 I Table 4.4. U. S. Exports--By Country--of Asbestos Manufactured Products in 1975* (Cont 1 d) I Net Quantity (Pounds) Value (Dollars) 6638117 Asbestos insulacion, heat or sound 2 Canada Hexico 1 Dominican Republic Venezuela Surinam i Peru Brazil United Kingdom The Netherlands Belgium Iran Pakistan Singapore Philippine Republic Mainland China Japan Australia New Zealand Egypt Ghana Other Countries Total 729,888 188,096 60,990 282,149 282,149 81,658 214,532 130,610 102,618 253,755 66,323 143,518 36l., 906 74,620 916,153 98,572 99,706 248,444 68.333 65,383 812,154 5,071,672 6638120 Asbestos textiles and yarns 3 Canada Nexico _7,749,305 1, 2Lf9 .no 3,664,189 7!17,770 Peru l Sweden United Kingdom 122,520 122,929 85,929 220,267 230,746 207,598 Ireland 45,100 145,350 I The Netherlands West Germany 487,222 195,984 127,799 252,944 Italy 54,043 274,700 1 Japan Australia Other Countries 23,646 1,020,703 307,061 146,510 614,452 651.974 Total 11,463,552 7,284,299 *U. S. Bureau of the Census, 1975b 37 FMSI 06164 }' \ I Table 4.4. U. S. Exports--By Country--of Asbestos Manufactured Products in 1975* (Cont'd) I Net Quantity Value (Pounds) (Dollars) 1 6638150 Asbestos protective clothing nexico Greece I Saudi Arabia Other Countries Total 76,580 200,311 68,643 463,975 809-,509 I 6638160 Asbestos manufactures, other than friction materials, NEC Canada Mexico Panama Jamaica Venezuela Peru i Chile Brazil Sweden United Kingdom The Netherlands West Germany Switzerland Poland Lebanon Iran Saudi Arabia Korean Republic Japan Australia New Zealand Republic of South Africa Other Countries Total 2,230,745 246,573 74,099 70,179 749,761 305,139 182,659 83,043 1,145,722 2,528,018 702,650 866,848 124,542 81,315 83,372 66,238 185,369 110,313 439,217 92,913 200,613 325,572 845,089 11,739,989 ! l 7:U. S. Bureau of the Census, 1975b l 38 1 FMSI 06165 t I Tabla 4.4. U. S. Exports--By Country--of Asbestos Manufactured Products in 1975* (Cont'd) I Net Quantity Value (Pounds) (Dollars) 1 6638202 Asbestos clutch facings for automotive use, including linings Canada 506,277 I Chile United Kingdom West Germany 63,447 195,978 226,888 Other Countries 281,518 I Total 1,274,108 l 6638206 Asbestos clutch facings, NEC, including linings Canada 160,905 t Other Countries Total 163,144 324,049 I 6638215 Asbestos brake linings for automotive use 1 Canada 5,726,553 4,681,018 I Guatemala Ecuador Chile 55,287 76,894 26,188 95,364 114,637 63,495 Belgium 83,388 133,965 Greece 426,808 177,068 Lebanon 146,100 165,735 Iran I Singapore Indonesia 164,803 133,140 118,415 156,894 82,093 73,897 Other Countries 700,518 8692554 ( Total 7,658,094 6,613, 702 6638225 Asbestos brake linings, NEC i 6 Canada 1,487,000 1,594,737 Mexico 274,572 173,896 Brazil 20,913 148,892 The Netherlands 26,700 271,849 Japan 15,909 64,690 Australia 48,975 136,347 l Other Countries Total 180,307 2,054,376 369,465 2,759,876 *U. S. Bureau of the Census, 1975b 39 FMSI 06166 { I 4.3 Imports Table 4.5 below lists the American imports of asbestos (unmanufactured) I from 1965 to 1975. 1 Table 4.5. U.S. Imports of Asbestos (Unmanufactured) for 1965 - 1975 l (Clifton, 1975; U.S. Bureau of the Census, 1975 a) l Year Asbestos Import in Thousands of Short Tons I 1975 1974 1973 [ 1972 1971 1970 1969 I 1968 1967 1966 I 1965 539 766 792 736 682 649 695 737 646 720 719 I { In 1975, 539,000 short tons of asbestos were imported into the U.S., as compared to 766,000 short tons in 1974. The decrease from 1974 to 1975 was i due to a shortage of asbestos in the Canadian supply caused by: 1) a destructive fire at Thetford Mines, Quebec, 2) a landslide at Johns-Manville's Jeffrey I Mine, Quebec, and 3) the 7-month-long strike of Quebec asbestos workers (Asbestos Magazine, December, 1975). During the first half of 1976, 329,000 short tons of asbestos were imported, a rate which is approximately midway between the 1974 I and 1975 figures. ( 40 FMSI~1~ I r Tables 4.6a and 4.6b list U.S. imports, by country, of unmanufactured asbestos in 1975 and the first-half of 1976, respectively. Table 4.7 gives I similar data for 1973- 1974. Table t+.B lists U.S. imports, by country, of { manufactured asbestos products in 1975. A hi:c;tod_cal breakdown for asbestos imports of chrysotile, crocidol:i.te, and amosite :Ls included in Table 4. 9, Asbestos Supply-Demand Relal:ionships. During the entire history of the asbef:;tos industry in the U.S., I domestic sources have been able to meet only a small percentage of U.S. require- { ments. Canada furnished 96% of all the asbestos tonnage imported by the U.S. (1969- 1973), but only a small portion (3%) was spinning grade fibers. The comparatively small tonnages imported from Africa are more important than would appear on a tonnage basis because they consist largely of special kinds and qualities unobtainable elsewhere (Clifton, 1975). 4.4 Supply-Demand-Use Table 4.9 g:i.ves the asbestos supply-ci.<:::ma.nd relationships for 1965 - 1974. The U.S. supply is a combination 0f imports, domestic mine production, industry stockpiles, and governmental stockpile releases. The U.S. supply is distributed among industry and governmental stockpile acquisitions, exports, and industry demand. The relative impm-umce of each is apparent from Table 4.9. The asbestos distribution by end use, grade, and type for 1974 is shown in Table 4.10. The mnjor buyers of asbestos and asbestos ore are listed in Table 4.11. 4.5 Asbestos Fiber Prices Asbestos prices are characterized by an erratic price history. Prices for Canadian asbestos increased about 8% :ln 1973, 39% in 1974, and 23% in 1975 . FMSI 06168 I ( Table 4.6a. U.S. Imports--by Country--of Unmanufactured Asbestos in 1975 I r INet Quantity Short Tons Customs Value (dollars)** F.a.s. C.i.f. { 2764010 Asbestos, Amosite Rep SAF 3,894 1,539,951 1,542,143 1,872,035 Total 3,894 1,539,951 1,542,143 1,872,035 I 2764020 Asbestos, Crocidolite, Blue Mozambq 118 16,090 16,090 29,033 [ Rep SAF Total 11,570 11,688 4,942,886 4,958,976 4,942,181 4,958,271 6,100,733 6,129,766 2764030 Asbestos, Chrysotile Crudes Canada 71 9,045 9,654 9,654 U King 277 82,982 82,982 121,299 Belgium 22 2,670 2,670 4,408 USSR 4,525 920,772 920,772 1,617,748 I Rep SAF Swazlnd Rhodesia 940 2,756 1,633 663,658 952,544 1,521,421 663,658 952,544 1,520,611 760,556 1,291,259 1,753,361 Total 10,244 4,153,092 4,152,891 5,558,285 2764040 Asbestos, Chrysotile, Except Crudes and Spinning Fibers Canada Rep SAF Rhodesia Total 7,637 115 382 8,134 5, 772,397 99,572 368,845 6,240,814 5,879,920 99,572 368,845 6,348,337 5,893,666 109,296 414,831 6,417,793 2764050 Asbestos, Chrysotile, Except Crudes and Spinning Fibers Canada 490,615 91,014,320 96,411,691 96,526,478 Mexico 73 14,876 14,876 14,876 U King 58 11,396 11,890 11,890 I USSR Italy Gaza St 86 38,640 39,805 40,214 44 12,540 12,540 16,461 152 25,914 25,914 25,.914 Rep SAY 220 68,025 68,276 95,123 Rhodesia 32 22,871 22,871 27,614 Total 491,280 91,208,582 96,607,863 96,758,570 2764060 Asbestos, Unmanufactured, Crudes, Fibers, Stucco, Etc., NES I. Canada Finland 5,222 329 776,931 32,841 858,340 32,298 859,639 51,915 Belgium 48 4,599 4,599 7,426 USSR 5,768 1,321,982 1,321,982 1,822,332 Italy Rep SAF Rhodesia 153 1,237 576 23,868 391,099 357,486 23,868 424,487 357,486 38,805 533,022 473,331 Total 13,333 2,908,806 3,023,060 3,786,470 l *Source: U.S. Bureau of the Census, 197Sa **Customs Value: Value of imports appraised by U.S. Customs Service. F.a.s. Value: Transaction value of imports at foreign port of exportation. I C.i.f. Value: Value of imports at the first port of entry in U.S. 42 FMSI 06169 { 1 I Table 4.6b. U;S. Imports--by Country--of-Unmanufactured Asbestos, January to June, 1976* , I Net Value (dollars) { I IQuantity Short Tons Customs F.a.s. c. i.f. I 2764010 Rep SAF Asbestos, Amosite 1,151 503,663 Oth Cty 20 469 [ Total 1,171 504,132 509,697 669 510,366 642,607 669 643,276 2764020 Asbestos, Crocidolite, Blue { Rep SAF Total 4, 712 4, 712 ' 2,315,466 2,315,46o 2,388,971 2,388,971 2,606,013 2,606,013 I 2764030 Asbestos, Chrysotile Crudes Canada ( Mexico U King Rep SAF t Rhodesia Total 289 234 119 351 1,095 2,088 125,175 125,486 55,992 193,918 1,115,230 1,615,801 129,108 126,948 55,992 193,913 1,115,230 1,621,196 129,108 126,948 64,090 220,191 1,200,965 1,741,302 2764040 Asbestos, Chrysoti1e Spinning Fibers Canada Total 2,394 2,394 2,053,568 2,053,568 2,110,240 2,110,240 2,111,611 2,111,611 2764050 Asbestos, Chrysotile, Except Crudes and Spinning Fibers Canada Fr Germ Rep SAF I Oth Cty Total it 298,988 1,086 396 17 300,487 60,006,713 202,826 217,440 3,919 60,430,898 63,427,681 202,826 219,660 3,919 63,854,086 63,598,407 257,094 235,599 3,919 64,095,019 2764060 Asbestos, Unmanufactured, Crudes, Fibers, Stucco, Etc., NES Canada 8,759 1,450,342 1,571,118 1,572,326 Fr Germ 823 179,840 179,840 320,577 USSR 6,700 1,292,721 1,293,001 2,079,238 Rep SAF 1,953 898,889 920,675 981,292 Oth Cty 54 21,969 22,029 22,368 Total I 18,289 3,843,761 3,986,663 4,975,801 *Source: U.S. Bureau of the Census, 1976a I~ 43 FMSI 06170 { I l ( Table 4. 7. U.S. Imports for Consumption of Asbestos (Unmanufactured) by Class and Country (Clifton, 1974) I Crude (lncludlnlli blue fiber) Textile fiber All other Total Year and country Quantity Value Quantity Value Quantity Value (abort (thou- (short (thou- (short (thoutonal oands) tons) sandal tonal sandal Quantity Value (short (thoutone I aanda l 1973 I Canada ---------------Finland ------.-------- _ Germany, Weat -------- Guyana ----------------IMtaallyasra-o-y-, --R-e-p-u-b--li-c---__-_--_ I Mexico ---------------Mozambique ----------- Panama. --------------PRohrotduegsaial, --S-o-u-t-h-e-r-n---_-__--_ 1,991 79 $397 21 51 27 S46 428 16,666 $6,020 746,988 1,027 808 8 8 48 6 12 1 $86,449 93 "ii 8 1 7 1 11 (l) 764.644 1,027 79 808 8 8 48 &6 12 1 846 $92,866 98 21 8 8 1 7 28 11 (1) 428 South Africa, Republic of .. ------ r Swaziland ------------Yemen ---------.-----Yugoslavia ------------ 21,629 200 4,510 122 8 130 1 8,427 733 2&,064 6.24t 73 880 196 50 11 DO 1l 88 88 -------------------Total __ ----------=~2~~~-7~9~5=~6~.6~0~0=~1~5-~B,;O;S==6~::o0;94~~7;61~-~87~5~~8~7~,8=2~0=~7~9~2-:;;4,::73=~98~,=9~U 1974 I Brazil ---- ___ ---------Canada ---------------Finland ---------------Germany, Weat -------- Italy ------------------ 'Mexico ----------------- Portugal -------- - --- - I Rhodesia -------------- 116 i3 99 as 1,7i7 1,oio 26,768 10,416 42 20 2 712,228 106,0S5 657 74 11 56 ii 42 20 789,111 557 100 1 66 4 1,721 2 116.614 74 86 11 2 1,012 l South Africa. Republic of ---------Swaziland ------------U.S.S.R --~----- ------- - 20,807 480 ---- 6,167 861 ---- - - 66 -- - - 16 - - - 3,291 451 --- - - 610 123 --- - - 23.664 480 461 ---- - 6,688 361 128 --- Total ------------ 22,718 6,576 26.839 10,438 716,607 106,808 766,164 128,822 1 Le11 than . unit. ( I 44 FMSI 06171 I 1 Table 4.8. u.s. Imports--by Country--of Manufactured Asbestos Products in 1975* f I Net Value (dollars) ( l I6618340 Quantity Pounds Customs F.a.s. Asbestos & Hydraulic Cement Articles NES c. i. f. Canada Mexico Guatmal Colomb U King Belgium W Germ Japan Austral Total 12,176,880 282,803 532,566 15,259,038 9,246 7,395,456 4,149,943 145,941 246,333 40,198,206 1,700,400 73,555 43,941 1,494,207 5,350 1,858,386 377' 706 30,725 '56,234 5,640,504 1, 773,749 73,564 43,941 1,494,215 5,368 1,858,022 377 '705 30,725 59,555 5,716,844 1,773,779 73,564 60,097 1,760,082 5,995 2,168,971 564,244 36,848 70,473 6,514,053 6638000 Asbestos Articles, NES, and Asbestos Yarn, Sliver, Rope, Etc., With or Without Hire Canada Mexico Venez Brazil Sweden Norway Finland Denmark U King Nethlds Belgium France W Germ Switz1d Spain Italy Yugoslv Greece India Phil R Kor Rep China T Japan Rep SAF Total 3,988,524 2,624,027 40,381 841,938 128,742 6,369 8,499 12,780 4,373,180 11,139 32,774 137,475 1,282,955 6,187 495,545 156,022 17,664 1,140 5,261 1,000 257,256 1,094,659 1,149,464 119,527 16,792,508 4,010,223 2,478,821 40,381 831,938 128,721 6,369 8,499 12,189 4,380,595 11,139 32,795 137,897 1,278,071 6,187 495,545 156,022 17,664 1,140 5,261 1,000 244,970 1,075,207 1;135,904 119,527 16,616,065 4,019,687 2,617,067 42,674 872,701 142,887 7,749 9,149 12,594 4,794,464 11,578 35,867 147,444 1,346,141 7,168 531,694 172,358 19,251 1,226 5,919 1,555 255,633 1,154,996 1,228,451 120,127 17,558,380 *Source: U.S. Bureau of the Census, 1975a 45 FMSI 06172 I 1 l I l [ Table 4.9. Asbestos Supply-Demand Relationships, 1965-74 (Thousand short tons) (Clifton, 1975) 1965 19e6 1967 1968 1969 1970 1971 1972 1973 1974 Total ----------------------------- 3.102 3.275 3.207 3.291 4.168 3.797 3,947. 4.182 4.588 4.536 ...... ...... .......~~~- -~.-....-- ~-=.--=--,_~=----~~~---=- Componen!O of US supply: Oomeshc m1nes ------------------------- 118 126 123 121 126 , 25 131 132 150 113 ----------------------------Goo.ernment release -------------------------- 12 Imports, thrysotlfe 681 1 669 1 618 15 703 669 11 626 8 660 16 724 7 771 29 747 Imports. crocctolte ---------------- 21 27 15 14 11 9 7 5 13 11 Imports. amoste ------------------------------ Industry stoc~s. Jal" 1 17 18 24 22 13 19 20 17 15 18 14 23 15 21 7 30 88 96 103 Total US !upply _.. 01stnbu110n of U S supply Government acqu1~bon Industry stocil. Dec 31 Exports lnduSII) demand 867 869 789 876 844 808 842 914 1.045 , 011 12 1 4,17 15 20 18 24 20 29 46 103 103 43 47 47 36 47 54 59 66 62 795 605 721 817 ;84 734 759 809 876 846 U.S demand panern Floormg products Asb'estos ce,ent pape Roohng producls Frcllcn products Asbts1os cemenl sheel Packng and gas1(ets lnsulaton Paper P'Oducls Text1tes Other Total u 5 demand 200 20~ 179 204 196 184 191 202 218 153 151 153 134 155 149 139 144 154 166 222 79 eo 71 82 79 73 76 81 87 76 .71 72 65 74 71 66 68 73 ;g 80 55 56 51 57 55 51 53 57 64 95 24 24 22 25 24 22 23 2~ 26 29 24 24 22 25 24 22 23 24 26 ,.16 16 , 4 16 16 15 , 5 '6 18 63 16 16 16 16 15 15 16 18 20 159 152 145 163 154 147 151 162 174 94 795 805 721 817 764 734 759 809 876 840 1 I Table 4.10. Asbestos Distribution by End Use, Grade, and Type, 1974 (Short tons) (Clifton, 1974) Chryootlle Group Group -A-a-be-st-o-s -cC-m-i.-.n-t -p-ip-e-_-_ -_ ----1-4-2-- 3 Asbt:"BtOlJ cement sheet _ FloorinSt Product:j Roofinll' product> . Packlnsr and ga.ket.s 100 1.900 Inaulation, thermal 100 Insulation. electricnJ triclion produds 5,600 Coatings llnd com,,uunth' Plastics 400 1,000 Textllea 700 14,200 Paper Other 800 Group 4 02,600 10,900 3,700 7,500 900 400 1,300 100 900 3,900 6,500 1,100 Group 6 20.~1)0 15.~0() 4'J,OOO 11,1110 7,500 100 1,6!::1 29,600 400 ~on ~Oil 400 GrtJUP 6 Group Group Tot.al 7 M chry"'~'t He 5~.o0o 12,700 1.400 3,400 r..soti 300 23,900 2,300 72,300 11,~00 104.500 46,300 10,300 2.~00 2.700 3!1.~00 31i,700 7.r.oo ~00 3~,:100 32.700 3011 400 r..aoo 1,5.200 !10.:)1)0 153.~00 73 .00 2}o.,j0!J 7,300 4,7on iY.fiOil 3';,900 16.~00 20.401) r.a.1nt1 ~~.41111 Total 1.200 28.1oo 12H,goo 137,300 102,300 39~.300 7,000 ~~.000 Crocldolite Amoslte AnthOIJhylllte Tot.al aabeatoo AAoabbeeetlooea eclel"mmeenntt aphipeeel -_------_-_-__-_--_---------------Floorinll' producta ________ --- ___ . Roolln11 produch -----------Paeklnll' and ~tukeh ------- -------lnulation, thermal .. lnulation, eh!ctrical . f'rlctlon producte _.. CoatinK and compound Plaatlca Textlin Paper OtheT 86,400 100 200 200 400 Total ~7 .ano - - - --~---- 1.100 4,800 1,700 1.800 500 9,400 200 22u2u.~o0o0 163.500 75,500 2~.~00 8.100 4,700 200 79.800 3i.900 700 1j .sou 20,400 63.300 - - -:n,aoo - - - - - -1,100 ~45.~00 46 FMSl 06173 - - - - - - -~""'l"'l! ~ '~ ~ Pl.~~~ ,~~ --~~~"'~- Table 4.11. Buyers of Asbestos and Asbestos Ore (Compiled from data furnished by U.S. Bureau of Mines, Washington, D.C.) Armstrong Cork Co., West Liberty & Charlotte St., Lancaster, Pa. 17604 Asbestos Textile Co., 165 West Wacker Dr., Chicago, Ill. 60601 Carlisle Corp., 621 North College, Carlisle, Pa. 17013 Celotex Corporation, L'Anse, Mich. 49946 Certain-Teed Products Corp., 120 East Lancaster Ave., Ardmore, Pa. 19003 Firestone Tire & Rubber Co., 1200 Firestone Pky., Akron, Ohio 44317 Flintkote Co., The, Inc., 400 Westchester Ave., White Plains, New York 10604 Foseco, Inc., 20200 Sheldon Rd., Brook Park, Ohio 44403 GAF Corp., 140 West 51st St., New York, N.Y. 10020 Garlock Inc., 250 Main St., Palmyra, N.Y. 14522 Gatke Corp., Box 308 East Winona, Warsaw, Ind. 46580 Hooker Chemical Corp., Kenton, Ohio 43326 International Vermiculite Co., Girard, Ill. 62640 Johns-Manville Corp., Greenwood Plaza, Denver, Colo. 80217 ""'...... Mead Corp., 118 West Flrst St., Dayton, Ohio 1,51,02 Minnesota Mining & Mfg. Co., 3M Center, St. Paul, Mi.nn. 55101 National Gypsum Co., Inc., 325 Delaware Ave., Buffalo, N.Y. 14202 Owens-Corning Fiberglass Co., Berlin, N.J. 08009 Pittsburgh Corning Corp., No. 1 Gateway Center, Pittsburgh, Pa. 15207 H.K. Porter Co., Inc., 601 Grant St., Pittsburgh, Pa. 15219 Raybestos Manhattan, Inc., Bridgeport, Conn. 06601 Rogers Corp., Rogers, Conn. 06263 Standee Brake Lining Co., 2701 Clinton Dr., P.O. Box 93, Houston, Tex. 77020 U.S. Gypsum Co., 101 South Wacker, Chicago, Ill. 60606 U.S. Plywood Corp., South River, N.J. 08882 -n -3: (/) Q a> .......,)o. ~ l Table 4.12 lists the average annual asbestos price from 1954 to 1974 and compares it to a figure based on constant 1973 dollars. Table 4.13 lists recent t prices for various grades and origins of asbestos. The remarkable disparity of l grade prices is evident from Quebec chrysotile fiber pri(es. Grade No. 7 (shorts) was priced at $89 per ton, while Grade No. 1 (crudes) cost $3496 per ton. 4.6 Future Outlook The best projections for future use of asbestos are reported by Clifton (1975). The information and projections contained in this subsection come directly from Clifton (1975). The domestic demand for asbestos is expected to increase at a slow I rate; the low rate of annual growth is expected to be 0.9%, while the high rate is expected to be 3.0%. The U.S. demand for asbestos in the year 2000 is projected to be about 1.25 times that of 1973 (876,000 short tons). Projection t trends for the U.S. demand are illustrated in Figure 4.2. The forecast for U.S. demand of asbestos by end use is given in Table 4.14. U.S. ASBESTOS DEMAND 93~ / / {/ 900 / / / ( . 873 -f'"// / ......877 "z' 0... "0' X / / \..~..\.. / /.../............... .,.t- ~ "'800 0z ...< ":I' 0 lEAST SQUARES PROJECTIONS: (A) LAST 20-YEAR TREND X (B) LAST 10-YEAR TREND 700 1954 1973 2000 BUREAU OF MINES U.S. DEPARTMeNT OF THE INlERIOR Figure 4.2. U.S. Asbestos Demand, and Projected Trends to 2000 (Clifton, 1975) 48 FMSI 06175 I I Table 4.12. Time-Price Relationship for Asbestos (Clifton, 1975) I Average Annual Price, Dollars Per Short Ton ( Year Actual Price Constant 1973 Dollars 1954 1955 1956 1957 1958 1959 1960 1961 1962 1963 1964 1965 1966 1967 1968 1969 ( 1970 1971 1972 1973 1974 82.34 84.61 89.78 88.09 90.50 91.17 94.62 95.60 94.85 92.44 98.70 97.92 100.63 101.91 98.93 110.03 115.64 117.54 116.63 122.22 122.27 141.72 143.65 147.42 139.38 139.66 138.35 141.44 141.00 138.26 133.00 140.00 136.38 136.35 133.74 124.75 132.41 132.01 128.32 123.16 122.22 110.90 49 FMSI 06176 I l t r I I ( I 1 t I I I 11, (' ,;~ ~ fit. I I~ I Table 4.13. Recent Prices of Various Asbestoses (Asbestos Magazine, December, 1975) ARIZONA As of April 17, 1975 Per Ton of 2000 Lbs .. F.O.B Globe, Arizona U.S. Dollars No. 1 Crude (Soli) No.2 Crude (SoH) AAA ......... . Group No. 3-Non!errous Filtering-Plastic $ $2000.00 1500.00 . ttOO 00 715.00- BOO 00 Group No. 4-Nonferrous Filtering-Plastic Group No. 7-White Shorts .. 700.0Q- 800.00 100.00- 200.00 QUEBEC As of December I, 1975 No. i-Crude No. 2-Crude No. 3-Spinning Fiber No. 4--Asbestos Cement Fiber No. 5-Paper Fiber No. 6-Paper and Shingle Fiber No. 7-Shorts Per Ton of 2000 Lbs . F.O.B. Mine Canadian Dollars $ $3496.00 1699 00 891 .00- 1463.00 492.00- 629 00 276 00- 392.00 236.00- 244.00 8900- 198.00 CASSIAR Per Ton of 2000 Lbs., F.O B North Vancouver, B.C As of August 1, 1975 Canadian Dollars Cassiar Mine C-1 . AAA Grade-Nonferrous Spinning Fiber /Canadian Group 3 AA Grade-Nonferrous Spinning Fiber /Canadian Group 3 A Grade-Nonferrous Spinnmg Fiber/Canadian Group 3 AC Grade-Nonferrous Spinning F1ber/Canad1an Group 3 AK Grade-Asbestos Cement FibertCanad1an Group 4 AS Grade-Asbestos Cement Fiber/Canad1an Group 4 AX Grade-Asbestos Cement Fiber/Canad1an Group 5 AY Grade-Asbestos Cement Fiber/Canadian Group 5 AZ Grade-Asbestos Cement Fiber !Canadian Group 6 $2916.00 1685.00 1340 00 1020.00 735.00 524.00 454 00 416 00 292 00 216 00 Clinron Mine CP Grade-Asbestos Cement FibertCanad1an Group 4 CT Grade-Asbestos Cement Fiber /Canad1an Group 4 CY Grade-Asbestos Cement Fiber/Canadian Group 5 CZ Grade-Asbestos Cement Fiber/Canadian Group 6 492.00 445.00 292 00 216 00 VERMONT Per Ton of 2000 Lbs., F.O.B. Morrisville, Vermont As of January 1, 1976 U.S. Dollars Grade 4T-Fiber Grades 50 1hru SA-Fiber Grade 60-Waste Grades 70 thru 7T-Shorts Grade 7TF-Fioats (Shor-ts) Grade 85-Shorts Hooker No. 1-in 50-lb. woven poly bagslelf. $ ..-$ 416 00 275.00- 324.00 200 00 83.00- 160.00 72.00 54 00 1211175 970.00 Hooker No. 2-in 100-lb. woven poly bags/eft 1211/75 465 00 50 FMSI 06177 I t I I Table 4.14. Projections and Forecasts for U.S. Asbestos Demand By End Use, I 1973 and 2000 (Thousand short tons) (Clifton, 1975) l 2000 I End Use 1973 Contingency Forecasts for United States Forecast Range I Forecast Base Probable Low High ( Asbestos cement pipe 166 475 178 479 190 I Asbestos cement sheet Flooring products Roofing products 64 218 87 100 65 104 68 360 233 372 236 150 93 148 94 Packing and gaskets 26 75 64 75 66 I Friction products Insulation 79 150 110 144 118 26 30 30 39 34 Paper 18 45 21 40 27 ( Textiles Other 18 20 19 24 21 174 400 199 387 260 Total 876 1,012 1,812 1,114 I I 51 FMSI 06178 ( I I 5.0 MINING AND MILLING I 5.1 u.s. Mines and Mills Although asbestos deposits are located throughout the United States I (Figure 5.1), asbestos is mined in only a few states. The map in Figure 5.2 designates the location of mines which are operating or which have been closed ( recently. In order of decreasing annual production, the mining states are California, Vermont, Arizona, and North Carolina. Table 5.1 lists the American mines which are operating or have recently closed, along with the associated i mills. All of the mines produce chrysotile asbestos with the exception of the Powhattan mine in North Carolina which produced anthophyllite asbestos. [ The largest mines are the Vermont Asbestos Group mine (formerly owned [ by GAF Corp.) in Vermont and the Calaveras Asbestos Ltd. mine (formerly con- trolled by H.K. Porter Co.) in Copperopolis, California (Asbestos Magazine, I December, 1975). The inactive Coalinga Asbestos Co. mine (Johns-Manville) was .the second largest mine in California and the third largest nationally. En- vironmental regulations are cited as the prime reasons for the closing of the [ Johns-Manville mine (Clifton, 1976; Harwood and Blasznak, 1974; Asbestos Magazine, December, 1974, 1975). Although the Powhattan mine in North Carolina was re- ported as inactive since 1973 (Harwood and Blasznak, 1974), a conversation with a Powhattan employee suggests that the mine is currently being operated. Potential mining has been discussed for Alamore, Texas (tremolite asbestos), Sonora, California, and the Yukon region of Alaska (Asbestos Magazine, f December, 1972, 1974). I It should be noted that actual mining production data for each mine cannot be accurately collected for proprietary reasons. Since California had, [ 52 ( FMSI~1~ - ,_.,...., --.,.,...,....., ,,_., f.;.._~):.~ 17~ ~-1 ~~~.,.~"m"~ ,.._.., - - ----- - Ut \.,o..) ~ Areas of the U. 5. wiiC~ .... ':.f contain natural oc.curren:~s of osl:lestiform minerals 1r. be1rock (areas contoininq igneous or metamorphic rocks) 'T1 -3en: Figure 5.1. Possible Areas of Asbestos Deposits (Harwood and Blasznak, 1974) 0en ~ co 0 I l I 1 I I ..:;) I """"'' N < l l l I ( I a it I.!!' i I I I I 0 Currently Operating A Recently Closed Figure 5.2. Asbestos Mines in the United States 54 FMSI 06181 - - - - - _ - - -- - - -~ ~ -~- .... -" -"! Table 5.1. American Asbestos Mines and Mills (Harwood and Blasznak, 1974; Clifton, 1974, 1975; Asbestos Magazine, December, 1972 - 1975) Note: All mines are open pit except those in Arizona, which are underground. V1 V1 -n 3: ~ 0 Q) ..a. co N Operating Company ~line Location 1. Atlas Asbestos Co. 2. Calaveras Asbestos Ltd. 3. Union Carbide Fresno County, Calif. Calaveras County, Calif. San Benito County, Calif. 4. Coalinga Asbestos Co., div. of Johns-Hanville 5. Vermont Asbestos Group Fresno County, Calif. Hyde Park, Vt. 6. Jacquays Mining Corp. Gila County, Ariz. 7. Asbestos Hfg. Co. Gila CoWlty? Ariz. 8. tletate Asbestos Co. Gila County, Ariz. 9. Powhattan ~lining Corp. Burnside, N.C. * 1973 figures (llarwuod nnd Blaszna.k. 1974) ** !Ull capacity figure Employees* Mill Location Estimated Production Employees* (Short Tons) Comments 20 Coalinga, c.,lif. 50 25,000/yr. Used in vinyl-floor tile 36 Copperopolis, 135 220/day Used in asbestos-cement Cali. pipes and sheets 36 King City, Calif. 50 110/day Used in reinforcing thermoplastics (Calidria); Japan is a major consumer 20 Coalinga, Calif. 50 110/day Closed in June, 1974 58 Hyde Park, Vt. 143 220/day Used in heat-resistant materials, mostly by CAF; purchased in 1975 from GAF B Globe, Ariz. -- Globe, Ariz. 5 3,000/yl'. Used for electrical and filter media; most is exported to Japan --- Closed Closed ----- Globe, Ariz. Closed Closed 4 Baltimore, Md. 8 700/yr.** f I I until recently, several operating mines, the Bureau of Mines has reported annual production for the state. But as a result of recent mine closings, the I annual California production report might be terminated (Clifton, 1976). I Table 5.1 contains estimates of Harwood and Blasznak (1974) for several indi- vidual daily mine productions and the estimate of Asbestos Magazine for annual production of two mines. Based upon the combined data of Harwood and Blasznak, Clifton, and Asbestos Magazine, we estimate that at the present time about 55-65% i I of the asbestos mined in the U.S. is mined in California, 35-45% comes from Vermont, and less than 5% is mined in Arizona and North Carolina. Until recent mine closings and sales altered the California production, California had accoun- I ted for nearly 70% of the domestic fiber. The lower limit for economical asbestos production is estimated at 4% asbestos containing ore (Berger and Oesper, 1963). Clifton (1975) evaluated the effect of continuous mine operations on the percent fiber recovery by a linear regression analysis of Quebec mine data (see Figure 5.3). He forecasts that as the age of a mine increases, the percent fiber recovery decreases. This will result in an increasing fiber production cost until mining is no longer prof- itable. By reason of analogy, the Quebec data should be generally true for U.S. mines, especially the Vermont mine, which is an outcrop of the Quebec deposits. Based on the above data, the Vermont mine appears close to being mined out. [ 5.1.1 Ore Characteristics The chrysotile asbestos content of ore varies between deposit locations. The lowest concentration is deposited in the Vermont ore which consists of less than 4% asbestos by weight, and the highest concentration is deposited in the Coalinga, California, district which is approximately 60% by I weight asbestos. I 56 FMSI 06183 l i I I :J 200 ..........Irr.. N < "z' .0..-.. CIJ: 0 :::r: \00 "z' ...:0::; i , , , , , , ,QUEBEC PRODUCTION TRENDS '~~<:) ~,., / / c..~/ q_O_,,.. / / / / REcovERy (Rock 20 -o "',;I 10 ("\ mz.... MILLED) I / ROC\<. ~\llEO ................... 0 \950 1960 1970 1980 \990 0 2000 Ore and waste rock exclus1ve of overburden BUREAU OF MINES U.S. DEPARTMENT OF THE INTERIOR Figure 5.3. Quebec Production Trends, From Analysis of 1951- 1970 Data (Clifton, 1975) I ! 57 FMSI 06184 I 1 I I I I I l I I 1 l 1 .I 1 1 The Vermont ore deposit is an outcrop of the large Quebec deposits in Canada. While the Vermont deposit contains some spinning grade fibers (Harwood and Blasznak, 1974), most fiber is shorter grade and is consumed in the manufacture of heat resistant products (Asbestos }mgazine, December, 1973). The Calaveras Asbestos Ltd. mine in Copperopolis, California, produces the normal long fibered form of chrysotile asbestos which is primarily used in asbestos-cement products (Harwood and Blasznak, 1974; Asbestos Magazine, December, 1975). Three mines, the.Coalinga (Johns-Manville), Atlas, and Union Carbide, are in close proximity to each other near Coalinga, California. They work an ore body which is 10 miles long and 0.25 miles wide. The ore from these mines is atypical of asbestos. Instead of a fibrous vein structure, the asbestos is in a platy, slippery form known locally as desert leather (Harwood and Blasznak, 1974). The fibers from this tract are short and therefore are used in floor tile and reinforced thermoplastics (Asbestos Magazine, December, 1971, 1975). Arizona produces an exceptionally high quality, low iron content asbestos, most of which is used for electrical insulation and for filtering media (Asbestos Magazine, December 1975). Most of the Jacquay Mine production is exported to Japan (Harwood and Blaszak, 1974). 58 FMSI 06185 t r 1 I 6.0 FRICTION MATERIALS Friction materials are used in practically all industries as a key component I in clutches for transmitting torque, brakes for slowing down or stopping motion, I or as torque limiters. Although friction applications to automobile brakes and clutches are the most important commercially, asbestos-friction applications are I not limited to brakes and clutches in automobiles, trucks, busses, construction equipment, and railro~d cars. Rather, these applications are found wherever I motion must be controlled. The following examples show the diversification of 1 friction material usage: farm tractors, presses, hoists, tensioning devices in production of wire and plastic rope and cable, lift trucks, machine tools, I shuttlecars, specialized mining equipment, chainsaws, drilling equipment, spin-- ning and knitting equipment, x-ray machines, wheel brakes, tape recorders, type\.;rriters, bicycle brakes, snowblowers, and washing machines (Daly ~__!:. al., I 1976). Asbestos is an important ingredient in these friction material products because it imparts strength, good friction properties, can withstand high tern- I peratures, and is a good insulator. ll! 6.1 Statistics 6.1.1 Use Quantity and Shipment Values From Table 4.9 (p. 46), it can be seen that U.S. demand for asbestos in friction products has ranged from sixty-five to eighty thousand short tons annually from 1964 to 1974. This amounts to approximately 9% of the total U.S. asbestos demand (consumption). The trend in the value of shipments of asbestos friction materials I is shown in Table 6.1. During the five year period from 1967 to 1972, shipment I 59 FMSI 06186 - - - - - - - -"'-,...,....., ~ "-i ",_ (i.?l!~~ <?i.~- ~ ~ Table 6.1. Value of Shipments of Asbestos Friction Materials (U.S. Bureau of the Census, 1972 Census of Manufacturers) SIC Product Code Product 32922 -- Asbestos Friction Materials - Total 32922 11 32922 15 Brake Linings: Woven, containing asbestos yarn, tape, or cloth Molded, including all non-woven types 32922 21 Disc Brake Pads 0\ 0 Clutch Facing: 32922 51 Woven, containing asbestos yarn, tape, or cloth 32922 55 Molded, including all non-woven types 32922 00 Asbestos Friction Materials, n.s.k. Total Product Shipments, including interplant transfers (millions dollars) 1972 1967 1963 209.5 144.4 177.7 10.2 113.1 14.2 13.5 95.6 19.9 48.5 3.6 17.2 16.1 2.0 , -3en: 0 G) ..a. C..... I I values increased by 45%, as compared to a 23% increase for the four-year period from 1963 to 1967. Using an annual figure of 9% for shipment value increases, I the total product shipments of asbestos friction materials would be approxiI mately $271.3 million in 1975 and $295.7 million in 1976. Table 6.1 also gives a breakdown for the major asbestos friction I material products. In 1972, brake linings accounted for nearly 59% of shipment values while clutch facings accounted for slightly over 32% of the shipment I values. If disc brake pads are included along with brake linings, then asbestos brake-materials account for 65.6% of the total value of asbestos-friction 1 materials. Clearly then, "brakes" are by far the most important commercial l product in the friction material category. 6.1.2 Industrial Firms [ Table 6.2 lists the U.S. manufacturers of asbestos-bearing friction materials along with their respective sales of friction materials in 1 1975. The larger firms include not only the essentially captive producers, such I as the Delco-Moraine and Inland Divisions of General Motors Corporation and the Cycleweld Division of Chrysler Corporation, but also the diversified industrial i product manufacturers, such as Raybestos-~fanhattan, Bendix, Abex, and H.K. - Porter. In addition, the list ir.cludes many smaller, typically single-plant I firms, which manufacture friction products for both the original equipment and replacement market. The first eight firms listed on Table 6.2 account for nearly 75 to 85% of the total estimated sales of asbestos friction products in 1975. This ratio is consistent with the historical pattern for the industry, which indi- cates that in the 1954 to 1967 period, the eight largest firms accounted for between 86 and 91% of the industry's value of shipments (Margolin and Igwe, 1975; U.S. Bureau of the Census, 1972). 61 FMSI 06188 J I I Table 6.2. U.S. Manufacturers of Asbestos-Bearing Friction Materials (Economic Information Systems, Inc., 1976; Margolin and 1 Igwe, 1975; SRC Estimates) 1 I Company Raybestos-Manhattan, Inc. Plant Location Stratford, Conn. Mannheim, Pa. Crawfordsville, Ind. Fullerton, Calif. Estimated 1975 Sales of Friction Materials ($ million) 110.0 I Bendix Corporation Troy, N.Y. Cleveland, Tenn. Abex Corporation l General Motors Corp. Cleveland, Ohio Troy, Michigan American Brakeblok Division Winchester, Va. Delco-Moraine Div. Dayton, Ohio Inland Division Dayton, Ohio rl. K. Porter Co. I Huntington, Indiana Richmond, Ky. Chrysler Corporation Cycleweld Division J Trenton, Michigan Borg \~arner Corporation Spring Division I... World Bestos Co. Bellwood, Ill. New Castle, Ind. I National Friction Products Corp. Logansport, Ind. 72.5 60.1 30.0 26.0 18.R 10.2 I Gatke Corporation Carlisle Corporation I Maremont Corporation I I " Warsaw, Ind. Ridgeway, Pa. Grizzly Products Division Paulding, Ohio 62 10.0 9.7 8.7 FMSl 06189 I I I Table 6.2. U.S. Manufacturers of Asbestos-Bearing Friction Materials (Cont'd) f I Company I Scandura, Inc. Plant Location Charlotte, N.C. Estimated 1975 Sales of Friction ~~terials ($ million) I Mar Pro Corporation Grizzly Brake Division Chicago, Ill. I Standco Industries Houston, Texas Forcee }1fg. Corporation Tappahannock, Va. 8.7 Royal Ind. Brake Products, Inc. Danville, Ky. 5.7 l Auto Friction Corp. L. J. Miley Co. I Friction Products Co. 1 United States Brake Lining Corp. Brassbestos Mfg. Corp. Lawrence, Ma. Chicago, Ill. Medina, Oh. Miami, Fla. Patterson, N.J. 5.7 5.5 4.0 2.9 1.7 Southern Friction Material Co. Charlotte, N.C. Reddaway Hfg. Co. Newark, N.J. 1.7 Molded Ind. Friction Corp. Prattville, Ala. Auto Specialties Mfg. Co. St. Joseph, Mich. I Lasco Brake Products Co. Oakland, Calif. California Blok Co. Gardena, Calif. MGM Brakes, Inc. Cloverdale, Calif. Wheeling Brake Block Mfg. Co. Wheeling, W.Va. Bridgeport, Ohio <1 63 FMSl 06190 I I I Table 6.2. U.S. Manufacturers of Asbestos-Bearing Friction Materials (Cont'd) I I Company Plant Location I Baldwin-Ehnet Hill, Inc. Trenton, N.J. I Thiokol Chemical Corp. P.T. Brake Lining Co. Trenton, N.J. Lawrence, Mass. Hunt/Airheart Products, Inc. Chatsworth, Cal. Re-Bilt Auto Products Corp. Brooklyn, N.Y. Estimated 1975 Sales of Friction Materials ($ million) <1 <1 I I 1 I I l 6l; FMSI 06191 I I I One important discrepancy in figures should be explained. For 1972, the U.S. Bureau of the Census listed the total value of shipments of as- I bestos friction products as $209.5 million which was projected as $271.3 million I for 1975 in Section 6.1.1. From Table 6.2, the estimated sales of asbestos friction materials in 1975 total nearly $370 million for the listed figures; the I companies with no listed figures may total another $50 million. The difference from the value of shipments as reported by the Bureau of the Census and the I estimates given in Table 6.2 are due to variations in definition and reporting coverage. Shipment value does not'include freight charges and excise taxes which are included in the actual sale cost. Also, the Bureau of the Census figures are based upon surveys at 23 asbestos-friction material establishments. Table 6.2 contains 44 establishments. Although the Bureau of the Census survey probably includes most of the larger establishments, the ones which were not surveyed are not available. 6.1. 3 Plants !~!' Figure 6.1 shows the geographical dispersion of friction materials '- plants in the U.S. Not surprisingly, they tend to be concentrated in and around the major metropolitan centers of the Northeast and Midwest, with a few plants located in California to primarily cater to the needs of the automobile assembly plants in that part of the country. As would be expected of a mature industry, most of the plants and equipments are old, usually over forty years of age, with the possible exception of newer captive facilities belonging to the automobile manufacturers. Pro- duction processes have changed only marginally over the years, and labor rather than capital intensity appears to be the norm in most of the older plants (Margolin and Igwe, 1975). 65 FMSI 06192 - - - - -.~~;,~.W."i-]!1 r.;.~ ~ ~ ""'"'""1':1 ~~ ~-- 1!1))1>11>?~ ~ ~ ~ ~ ,_-u - (j\ (j\ "T1 3:: CJ) e0n Figure 6.1 Geographical Dispersion of U.S. Friction Materials Plants (Modified from Margolin and ~ U) Igwe, 1975) w 6.1.4 Future Projections for Asbestos Use (Clifton, 1975) Asbestos demand for friction products was projected to the year l 2000 at an annual growth rate of 1.50 percent. This figure was based on a formula derived from least-squares regression analysis of total asbestos demand I modified by the estimated growth in the automobile industry and economic indil cators, which showed the best correlation. Asbestos is an important part of many types of friction materials 1 for use in automobiles, trucks, and other transportation equipment. Modern industry could scarcely function without asbestos friction materials. In addi- I tion to using asbestos in brake linings, today' s motor cars, equipped with automatic transmissions, get their drive from metal transmission disks, which I are covered with a super-tough paper containing crocidolite asbestos. The average automobile with power shift contains from 8 to 12 of the paper lined disks. Although the quantity of asbestos in each transmission is small, the output of more than 8 million automatic transmissions annually requires disk paper production in hundreds of tons. A new composition disk-brake-shoe unit containing asbestos, designed to meet the critical braking requirements for the new 150-ndle-per-hour passenger train systems, has been developed. Based on an estimated forecast of the number of motor vehicles produced in the year 2000 (approximately double 1973 production) and on the assumption that the use of asbestos per vehicle will remain at present levels, the forecast for asbestos demand in user-operated vehicles is projected to 118,000 tons. An increased number of public transportation vehicles and equipment using parts made of asbestos or maintaining the present quantity used per vehicle could result in a demand as high as 144,000 tons. 67 FMSI 06194 l I I 6.2 Manufacturing Process Technology I Several different processes are used to manufacture asbestos brake linings and clutch facings. Manufacture can be accomplished by a molding proc- I ess, in a dry or wet-mixed state, or by a woven process; these processes, which are described below, are taken from Gregg (1974). The raw materials used for i forming asbestos-friction materials are discussed in Section 6.3. I 6.2.1 Molded Products 6.2.1.1 Dry-Mix Process 1 The manufactur'ing steps typically used in dry-mix molded brake lining manufacture are shown in Figure 6.2. The bonding agents, metallic [ constituents, asbestos fibers, and additives are weighed and mixed in a two- I stage mixer. The mix is then hand-tamped into a metal mold. The mold is placed in a preforming press which partially cures the molded asbestos sheet. The asbestos sheet is taken from the preforming press and put in a steam preheating mold to soften the resin in the molded sheet. The molded sheet is formed to the proper arc by a steam-heated arc former, which resets the resin. The arc-formed sheets are then cut to the proper size. The lining is then baked in compression molds to retain the arc shape and convert the resin to a thermoset or permanent i!f condition. The lining is then finished and, after inspection, is packaged. The finishing steps include sanding and grinding of both sides to correct the thickness, edge grinding, and drilling of holes for rivets. Following drilling, the lining is vacuum-cleaned, inspected, branded, and packaged (Gregg, 1974). 6.2.1.2 Wet-Mix Process Figure 6.3 shows the major steps in the manufacture of wetmixed molded brake linings. The name "wet mix" process is a misnomer and refers 68 FMSI 06195 I I l l RAW MATERIALS STORAGE PROPORTIONING I I PREFORMING PRESS I COOLING WATER I ~~~~-~~COOLING WATER ~--~~---~~CONDENSATE COOLING WATER STEAM ~~~~--------~ ~...;a,....o"'-'--:~~la!IBs-COOLING WATER b..----~~~ CONDENSATE COMPRESSJON MOLD BAKING OVEN +ousT INSPECTION PACKAGING STORAGE CONSUMER Figure 6.2. Dry-Mixed Brake Lining Manufacturing Operations (Gregg, 1974) I 69 FMSI 06196 r r I to the use of a solvent. The ingredients of the molded lining are actually I relatively dry. After weighing, they are mixed in a sigma blade mixer. The mixed ingredients are then sent to grinding screens where the particle size of I the mixture is corrected. The mixture is conveyed to a hopper and is forced from the hopper into the nip of two form rollers which compress th~ mixture into I a continuous strip of friction material. The strip is cut into the proper I lengths and then arc-formed on a round press bar. The cutting and arc forming operations are done by separate units. The linings are then placed in racks and either air-dried or oven-dried to remove the solvent. An alternative process is to place the arc-formed linings in metal molds for baking in an oven. From the ( ovens, the linings are finished, inspected, and packaged (Gregg, 1974). I Molded clutch facings are produced in a manner similar to the wet-mixed process. The rubber friction compound, solvent, and asbestos I fibers are introduced into a mixer churn. After the churn mi.xes the ingredients, the mixture is conveyed to a sheeter mill which forms a sheet or slab of the materials. The sheet is then diced into small pieces by a rotary cutter. The pieces are placed in an extrusion machine which forms sheets of the diced material. The sheets are cut into the proper size and then punch-pressed into doughnut-shaped sheets. The scraps from the punch press are returned to the extrusion machine. The punched sheets are placed on racks and sent to a drying oven and then a baking oven for final curing and solvent evaporation. The oven- l dried sheets are finally sent to the finishing operations. Figure 6.4 illustrates the steps in the manufacture of molded clutch facings (Gregg, 1974). I 6.2.2 Woven Products Woven clutch facings and brake linings are manufactured of high strength asbestos fabric that is frequently reinforced with wire. The fabric is 70 FMSI 06197 I I l RAW MATERIALS STORAGE l PROPORTIONNG I I GRINDING SCREENS i TWo-ROLL Fc::lRMHG ( I 'SOLVENT A--ruaat.i!l I SOLVENT i . A"""""'"=-"____ a lo~\:..~~ Cl!ll 11111 001 a i>- OUST i INSPECTION PACKAGING STORAGE CONSUMER I I Figure 6.3. Wet-Mixed Molded Brake Lining Nanufacturing Operations (Gregg, 1974) 71 l FMSI 06198 I I I RAW MATERIALS STORAGE l PROPORTIONING I COOLING WATER STEAM ( COOLING WATEA CONDENSATE I I -..., I I I I (RECYCLED SCUDS, I I II .... .... .J I SOLV!:NT r SOLVENT .,. I I,. l INSPECTION PACKAGING STORAGE I CONSUMER I Figure 6.4. Holded Clutch Facings Manufacturing Operations (Gregg, 1974) l 72 t FMS\ 06199 I I predried in an oven or by an autoclave to prepare it to be impregnated with I resin. The fabric can be impregnated with resin by several techniques: 1) immer- sian in a bath of resin, 2) introducing the binder in an autoclave under pressure, I 3) introducing dry impregnating material into carded fiber before producing yarn, and 4) imparting binder into the fabric from the surface of a roll. After I the solvents are evaporated from the fabric, it is made into brake linings or I clutch facings. Brake linings are made by calendering or hot pressing the fabric in molds. The linings are then cut, rough ground, placed in molds, and I placed in a baking oven for final 'curing. Following curing, the lining is finished, inspected, and packaged (Gregg, 1974). Figure 6.5 illustrates the manufacture of \YOven clutch facings. I The treated fabric is cut into tape-width strips by a slitting machine. The strips are wound around a mandrel to form a roll of the fabric. The roll is pressed in a steam-heated press and then baked in an oven to cure the resin in the clutch facing. Following curing, the clutch facing is finished, inspected, and packaged (Gregg, 1974). 6.3 Composition of Friction Materials Many raw materials, including some whose exact roles are regarded as proprietary knowledge, are used in varying quantities in the manufacture of friction materials. The major, or foundation constituent, of practically all l organic friction materials is asbestos fiber. The asbestos usually used in friction materials is chrysotile from Quebec or Vermont (Jacko and DuCharme, 1973); grades 3-7 are used; however, grades 5 and 7 account for nearly 83% of ( the total (Clifton, 1975). Asbestos is used because of its thermal stability, relatively high friction level, and reinforcing properties. 73 FMS\ 06200 I ( It I TREATED FABRIC I I ( I COOLING WATER [ COOLING WATER COHOEII!SATE I ---+ DUST INSPECTION PACKAGING STORAGE [ CONSUMER Figure 6.5. Woven Clutch Facings Manufacturing Operations (Gregg, 1974) 74 FMSI 06201 Asbestos alone does not offer all of the desired friction properties. Therefore, other materials, known as property modifiers, are added to the ashes- f tos fibers. Modifiers are varied in type and content to provide desired levels ( of effectiveness, wear, fade, recovery, and noise. A binder is also added to hold the other materials together with adequate strength. ( 6.3.1 Binders I Table 6.3 lists binders and property modifiers which are used in automotive brake linings. The binders used in the automotive industry today are I primarily phenolic-type resins which are noted for high binding efficiency and ability to withstand pyrolytic breakdown (Rohl et al., 1976). They are prepared I as the condensation product between the appropriate phenol (sometimes modified) I and formaldehyde in the presence of an acidic catalyst to yield the novolak. When mixed with an appropriate curing agent, they polymerize at elevated tem- peratures to an insoluble, infusible mass (Jacko and DuCharme, 1973). Other resin systems in wide use are based on elastomers, drying oils, or combinations. 6. 3. 2 Property Hodifiers Perhaps the widest range of materials used in friction products are the property modifiers. Table 6.3 indicates the range and diversity of these modifiers. In general, property modifiers can be divided into two classes: non-abrasive modifiers and abrasive modifiers (Jacko and DuCharme, 1973). 6.3.2.1 Non-Abrasive Modifiers Non-abrasive friction modifiers can be classified further as low friction and high friction. The most common and best known of the high I friction materials is known as friction dust. This is a cured resinous material. The most frequently used variety is derived from cured or polymerized I 75 fMS\ 06202 1 { Table 6.3. Binders and Property Modifiers In Automotive Brake Linings (Rohl et al., 1976; Jacko and DuCharme, 1973; various patent lit.erature; Bark et al., 1975) i Binders Property Modifiers Use Function Phenolic-type resins Graphite Lower friction coefficient and noise Natural rubber Coke II I Buna N rubber Nitrile rubber Tire sc-rap Coal Carbon black Gilsonite II " II I Pitch Cork Gilsonite Elastomers I Drying oils Rottenstone ( Quartz Wollas t{oSnii0t e2 ) Brass Chips Sio 2) (CaSi03) Zinc and compounds Remove decomposition deposits II II II II Alluminum II 1 Limestone Clays (Caco3) Improve wear resistance II i Silicas Barite II II Lead and compounds Lubricant to prevent grabbing ( Friction dusts See discussion in Section 6.3.2.1 I Antimony compounds Calcium compounds Not available II Copper and compounds " I Barium hydroxide Potassium dichromate Hagnesium carbonate " II II Iron oxide Cryolite Fluorspar (Na6A1F3) " " II Cardolite II Nickel Naptha " II Sulfur II Methylethyl ketone II Molybdenum disulfide Lubricant Calcium fluoride Lubricant I I 76 I FMSI 06203 l 1 cashew-nut-shell liquid, chemically a phenolic compound. When heated with I hardening agents, such as hexamethylenetetramine or formaldehyde, it becomes sufficiently hard or polymerized to be granulated. Many other cured resinous or { polymeric materials, some with fillers, are also used. Certain friction dusts are combinations of these materials and cashew resin. Ground rubber is normally l used in particle sizes similar to, or slightly coarser than, those of the cashew I friction dusts for noise, wear, and abrasion control (Jacko and DuCharme, 1973). Carbon black, graphite, petroleum coke flour, or other I carbonaceous materials may also be added as friction modifiers to lower the friction coefficient or to reduce noise. These materials are normally used in t the form of fine powders or particles, although graphite is sometimes used in coarse particles or pellets. The amount of friction modifier added is dependent upon the properties desired in the final composite (Jacko and DuCharme, 1973). 6.3.2.2 Abrasive Modifiers Abrasive modifiers, such as alumina and the silicas, are usually used in relatively small amounts and only in very fine particle sizes (generally 100 mesh or finer). Particle size is limited by the fact that large particles of such hard materials would groove and wear the mating surfaces. Minerals are generally added to improve wear resistance at minimum cost. Those most commonly used are ground limestone (whiting) and barytes (barium sulphate), l though various types of clay, finely divided silicas, and other inexpensive or abundant inorganic powders may also perform this function. Such materials are inorganic in nature and tend to detract from noise properties and mating surface l compatibility (Jacko and DuCharme, 1973). Metals or metal oxides may also be added to perform specific l functions. Brass chips are frequently found in heavy-duty friction materials I 77 FMSI 06204 J \ where, as scavengers, they break up undesirable surface films. Zinc and aluminum are also used. Zinc chips, in relatively small amounts, can contribute 1 significantly to recovery of normal performance following fade (Jacko and DuCharme, 1973), 6.3.3 Composition The average composition of a typical automobile and truck brake lining is shown in Table 6.4a. Individual mixes may vary considerably from these I averages. Table 6.4a. Average Brake Lining Composition (Lunch, 1968) If l Ingredient Automobile Truck Asbestos Resins and Polymers Oxides and Pigments I Metals Carbon, Graphite, etc. l 55 28 9 3 5 100% 33 48 16 2 1 100% Manufacturers are very reluctant to release their exact composi- tions due to proprietary considerations. A search of patent literature reveals limited information, although several examples from the patent literature are given in Table 6.4b. 6.3.4 Sunnnary The tables and examples given in Section 6.3 have been included lv to illustrate the wide variety of compositions which are possible for fabrication of automotive and truck brake linings. Brake linings have been singled out 1 78 ! FMSl 06205 J 1 I Table 6.4b. Brake Lining Compositions from Patent Literature 1 ExamEle No. 1* I Asbestos Barite 55 10 Phenolic resin binder 20 l Brass Magnesium carbonate 5 8 Limestone 8 l Organic calcium powder 10 Examrle No. 2** Asbestos Phenolic resin Nitrile rubber Cashew dusts Calcium fluoride Copper iodide 60 15 3 12 7 3 I Example No. 3*** Asbestos Barite Graphite Brass Phenolic resin Lead oxide Buna N rubber Naphtha Copper sulfide Methyl ethyl ketone 35 2.5 7 13 7 11.5 8 7 12.5 4 Example No. 4**** Asbestos Tarry residue Barite Phenolic resin Graphite *Sakata et al., 1974 (Hitachi) ** Toyota Central Research and Development Labs, 1971 *** Keller, 1969 (Abex) **** Mitchell, 1974 (duPont) so 12 20 20 2 I 79 FMSI 06206 I 1 1 from the asbestos-friction products for examination because of their dominance t of the asbestos-friction products market as shown in Table 6.1. When the variations of compositions are coupled with the variations of manufacturing process 1 methods (as described in Section 6.2), it is possible to view a brake lining made by company A as substantially different from a brake lining made by com- I pany B, although the intended use applications may be the same. From this t standpoint, it is entirely reasonable to speculate that asbestos emissions during automotive brake use may vary in concentration, depending upon composition and process manufacture of the individual linings. 6.4 Asbestos Emissions from Brake Lining Use 1 Asbestos has been identified in over 200 air samples taken from the atmosphere of 49 cities in the United States (Nicholson et al., 1973); asbestos was present in every sample taken. Asbestos has also been found in air samples from European cities (Holt and Young, 1973) and from air samples collected in Australia (Alste et al., 1976). The asbestos manufacturing industry may not be the source of the asbestos emissions found in urban air samples cited above. According to Holt and Young (1973), 11 the object of our investigations was only to determine whether asbestos fibres are present in the atmosphere of towns where there is no asbestos industry. The result was positive in every case. 11 The source of asbestos emissions, in the absence of asbestos mining and industry, is a matter of speculation. Holt and Young (1973) and Selikoff et al. (1972) suggest that the asbestos source may be construction which uses building materials made from asbestos. Alste et al. (1976) consider, as a source, that asbestos emitted from automobile brake linings is a 11strong possibility. 11 Alste et a1. (1976) found that the air concentration of asbestos I 80 FMSI 06207 1 t was much higher at points where considerable braking occurred, as compared to 1 points of virtually no braking. This result is apparently in agreement with measurements made in New York City which found that the asbestos air concen- l trations contiguous to a toll booth were three to five times higher than back- ground levels (Anderson ~ al., 1973; Nicholson et al., 1971). This subsection I will consider the possibility of asbestos emissions from brake lining use. 6.4.1 Published Literature A number of articles and publications (Alste et al., 1976; Rohl et al., 1976; Jacko and DuCharme, 1973; Jacko et al., 1973; Bush et al., 1972; Hatch, 1970; Hickish and Knight, 1970; Lynch, 1968) have discussed the ( asbestos emissions from the use of brake linings. Table 6.5 gives a brief 1.-t summary of this published data in terms of methodologies and results. As can be seen from Table 6.5, there are important discrepancies in the results obtained. 1 6.4.1.1 Discrepancies in Asbestos Content of Emissions or Debris Lynch (1968), Hatch (1970), Hickish and Knight (1970), and I Jacko and DuCharme (1973) reported figures in the range of 1% or less for the asbestos content of emissions or debris resulting from brake lining use. Bush et al. (1972) and Roh1 et al. (1976) arrived at figures which are substan- 1 tially higher, 44% and 2-15% asbestos content, respectively. While Alste et al. (1976) did not arrive at a percent figure, they did conclude that the major effect of braking appears to be separation of bunches of fibres and reduction of I their average length, but not alteration of their crystal structure. This conclusion may certainly result in a relatively high asbestos content for wear I debris. I 81 FMSI 06208 - _ - - - - -~,...... _.. ~ ~ !I'="Jil ~;\111~ ~ -""' --.. _.. - . ...._ Table 6.5. Summary of Published Data - Asbestos Emissions from Brake Lining Use Publication Source Method Used to Collect EmiSsiOn or Debris Samples !<.ethod Used to Determine Asbestos Content of Emission Debris Samples Asbestos Particle Size Distribution Asbestos Content of Emission or Debris Lynch, 1968 Laboratory simulations utilizing brake-testing machines or dynamometers. Samples collected on 0.8 ~ pore size membrane filters. Electron micrographs Not discussed <1%, except under severe-stress conditions Hatch, 1970 A dust cloud was generated by using compressed air jets to remove dust from brake linings in an auto repair garage. Sampl~s vere collected by means of a hand pump loc~ted in center of dust cloud. Not stated 94% of fibers fell in 2-5 ~m length category. Only 6'! were longer than 5 um~ ~11. Hickish and Knight, Samples were collected directly from debris Not stated Not discussed 1. 6% and less 1970 CXl N remaining as brake dust and from membrane filters exposed during brake cleaning operations utilizing compress~d air. Filter pore size is not given. Bush !'_ al., 1972 Labor.\tory simulations utilizing a disc brake assembly mounted on an inertial dynamometer. Sam~les were collected on suitable filter paper. Neutron activation Not discussed ~441. (this figure is not accuratei see discussion in Section 6.4.1.1) Jacko and DuCharme 7 1973 (contains same data as Jacko .!_ al., 1973) Sampl~s were generated by operating a standard American car on a dynamometer simulating driving conditions. Brake and clutch assemblies were enclosed by specially designed collectors. Samples were collected from 1) dropouts during usc, 2) dust retained in lining assemblies, and 1) airborne samples collected on membrane filters. Optic.:sl and electron microscopy 30% of fibers were from 0.25-D.50 "m in length; 60% were longer than 0.5 ~m. 0.231. overn11 average (an independent check done by Batelle Labs gave a figure of 0.171%) "TI e3n: eCn) N C) CD - - - -' - - - - - -_..--... ............. ,~-.JI ~~:.d ~~ ~ )11"- ""'~' ~ .... Table 6.5. Summary of Published Data- Asbestos Emissions from Brake Lining Use (Cont'd) Publication Source Method Used to Collect Emission or Debris Samples Method Used to n(.'ltnninl' A!-lobc~:Hu~; Cout(ilt of Emission Debris Samples 1\lilH':JlOt; Particle Size Distribution Asbestos Cont"nt of Emission or Debris Rohl ~':_ !'l, 1976 Ten samples of automobile brake drum dusts X-ray di ffractometry 2-15%; average of 3-b% were collcct<"d from maintcnane1. shops in the. New York an.<I. Tran~misaion electron 807. of fibers were Consistent with, but nticroscopy, sclcct"d shorter than lower than, area electron 0.4 ~m length. quantitative diffraction, and determination made cwo electron microprobe analyses by x-ray diffractometry; no percentages are given A1ste et ~-, 1976 Samples were taken from fresh and worn brake linings and from the atmosphere n~ar a freeway. Electron microscopy 3nd electron diffraction Majority were <2 l-Im in maximum linear dimension. No percent figore giveni however, conclusion was that major effect of braking appears to be in separating bunch~s of fibres and reducing their average length, but not in altering their crystal structure ., 3: ~ 0 C N ~ 0 j I I The 44% figure computed by Bush et al. (1972) is based upon I a neutron activation analysis, which is a technique for finding the elemental composition of a sample by irradiating the sample with neutrons, thereby causing I the elements to become radioactive. Bush ~ al. is careful to point out that chrysotile asbestos is a magnesium silicate and neither magnesium or silicon are I able to be determined utilizing the particular technique. Therefore, asbestos I content of the wear debris was determined by means of a scandium concentration. Scandium was a trace element (~ 4 ppm) present in the chrysotile used in the I experiment. Neutron activation can be a very precise and useful technique for determining elemental composition; unfortunately, the asbestos content of any I particular wear debris sample cannot be computed by an elemental analysis. I Chrysotile asbestos is a unique crystal structure of a magnesium silicate (see Section 2.1); heat or other physical means can destroy this unique structure, I thereby creating a different compound with different properties. However, the elemental composition of the different compound will be identical with chryso- I tile. Both Rohl et al. (1976) and Jacko and DuCharme (1973) determined that the I magnesium:silicon ratio of an asbestos friction material is the same before use and after use (as determined from wear debris via chemical analyses). There- I fore, the 44% asbestos content figure computed by Bush et al. (1972) does not represent the asbestos content, but rather it represents the magnesium silicate I content. When considering wear debris from friction materials, neither neutron activation nor chemical analyses are useable techniques for analysis of asbestos I concentration. I The major conflict to be resolved is the high asbestos content suggested by Alste (1976) coupled with the 2-15% asbestos content figure I 84 I FMSI 06211 J obtained by Rohl et al. (1976) versus the 1% and less figures obtained by the 1 remaining publication sources listed in Table 6.5. The difference of results appears to be based upon collection methodologies, analysis techniques, and l interpretations. 6.4.1.2 Collection Methodologies and Particle Size Distribution I The first major consideration of methodology is the type of l samples which were collected; that is, samples produced by laboratory simula- tions versus samples produced during actual, real-life use. Jacko and DuCharme l (1973) and Lynch (1968) collected laboratory samples produced by simulations while Alste et al. (1976), Rohl et al. (1976), Hatch (1970), and Hickish and 1 Knight (1970) collected real-life samples. There may be an open debate as to 1 which collection method produces the best final results. Laboratory simula- tions, as conducted by Jacko and DuCharme (1973), allow entire brake assemblies to be enclosed, and therefore, all conditions could be monitored or controlled and all emissions can be collected. On the other hand, samples collected from real-life use are not only relevant, but they may provide the truest indication 1 as to the asbestos emitted from brake lining use. Conditions encountered during actual use may not be totally reproducible in the laboratory; hence, the asbes- tos emission factors may be significantly different. Another area of consideration is the asbestos particle size I distribution in the wear debris. Rohl et al. (1976) determined that approxi- mately four-fifths of the wear debris fibers are shorter than 0.4 ~m in length while Jacko and DuCharme (1973) found that 30% of the fibers were from 0.25-0.50 ~m in length. According to Rohl et al., some of the discrepancies between their data and those of Jacko and DuCharme may be attributed to Jacko and DuCharme's 85 FMSI 06212 l 1 r use of lower magnification (22,000X vs. 42,000X), at which fibers shorter than 1 0.20 ~m may not be easily seen or identified on the electron microscopic screen. Hatch (1970) also produced size distribution figures, finding that 94% of the fibers fell in a 2-5 ~m length range; however, there is no indication that Hatch attempted to look for fibers shorter than 2 ~m. Alste et al. (1976) found that I the majority of particles, which consisted of small bundles of fibers, had a l maximum dimension of ~ 2 ~m. The best available data (Rohl et al., 1976; Jacko and l DuCharme, 1973; Alste et al., 1976) indicates that a very high percentage of the asbestos present in brake lining wear debris is shorter in length than 2 ~m, 1 with a substantial portion shorter than 0.5 ~m. 6.4.1.3 Analysis Techniques Hickish and Knight (1970) fail to discuss analysis techniques used to determine the asbestos content in their wear debris and, also, do not fully describe collection methods. Under these circumstances, it is difficult to accept their results at face values. Hatch (1970) is deficient in analysis methodology also, although it appears that he used electron microscopy in sizing particles down to 2 ~m. Since the Rohl et al. (1976), Jacko and DuCharme (1973), and Alste et al. (1976) studies are the best studies yet conducted on brake lining asbestos emissions, a closer examination of the three is warranted. As seen from Table 6.5, Roh1 et al. determined their 2-15% asbestos content from X-ray diffractometry (both continuous and step-scan modes were used). According to Jacko and DuCharme, "asbestos is readily identified when alone or in simple mixtures at high concentrations by the following analytical methods: X-ray diffraction, thermal methods, microscopy, and infrared 86 FMSI 06213 1 analysis. However, in complex mixtures, or at very low concentrations, the I analysis for asbestos is very difficult. In brake wear debris, the problem is compounded because the reaction products of asbestos, fosterite and olivine, have similar elemental ratios and similar X-ray diffraction patterns. The only sensitive method Hhich can be used is microscopy." This conclusion by Jacko and J DuCharme is apparently based upon the assumption that samples that they were l going to produce would contain 1% or less asbestos; an accompanying table estimated the asbestos content of wear debris to be less < 1%. Apparently they did not use X-ray diffraction becausethey assumed the asbestos concentration would be too low. In the percent range reported by Rohl ~ al., namely 2-15%, X-ray diffraction is very likely an appropriate technique for quantitative chrysotile determination. Two published reports (Goodhead and Hartindale, 1969; Crable, 1966) of X-ray diffraction techniques for determination of asbestos in dusts support the contention that chrysotile can be quantified with good accuracy in the percent ranges reported by Rohl et al. Rohl et al. further verified chrysotile presence by 1 transmission electron microscopy and selected area electron diffraction. l "Chrysotile was found, both in fiber and fibril form, with unaltered structure and chemical composition. Its frequency of occurrence was consistent with, but lower than, the quantitative determination made by X-ray diffraction analysis. However, it should be noted that X-ray diffraction analysis is based on both free fibers and fibers present in clumps; the latter would obscure the presence of discreet fibers on electron microscopy study." Alste et al. (1976) determined the presence of chrysotile asbestos by electron microscopy and electron diffraction and concluded that the 87 l FMSI 06214 l l major effect of braking appears to be in separating bunches of fibers and l reducing their average length but not in altering their crystal structure. This is an important result in terms of the following consideration: If only 15%, or { downwards to less than 1%, of wear debris is asbestos, what happens to the major portions of the asbestos originally present in the brake lining? Lynch (1968), I Hatch (1970), and Hickish and Knight (1970) present a prevalent theory that "hot spots" created during braking cause the local asbestos fibers to undergo thermal degradation which results in thermal metamorphosis of the asbestos into a dif- 1 ferent mineral, such as fosterite (olivine). Jacko and DuCharme (1973) assumed that 20-40% of the wear debris composition would be olivine. However, according l to Alste et al. (1976) concerning wear debris from brake linings, "there was no indication from the diffraction pattern of the presence of fosterite;" this result was in agreement with Rohl et al. (1976) who also could not verify the presence of fosterite. Rohl et al. (1976) and Jacko and DuCharme (1973) discussed other forms of brake lining wear, in addition to thermal wear, such as abrasive wear and macroshear wear. However, the end result is probably this: the asbestos present in the original brake lining, excluding the asbestos which is emitted in the wear debris, is converted by thermal or other physical processes into magnesium silicates or other recrystallized magnesium silicate structures different from asbestos. In addition to unaltered chrysotile fiber in the wear debris, Rohl ~ al. (1976) observed partially altered and completely recrystallized fibers. Holt and Young (1973) reported that some of the asbestos fibrils collected in European city air appeared to have been heated. 6.4.1.4 Other Considerations The Rohl ~ al. (1976) study is based upon a wider and more random sampling than that of Jacko and DuCharme (1973). Rohl et al. selected l 88 FMSI 06215 l wear debris samples from ten random automobiles undergoing brake maintenance 1 while Jacko and DuCharme's wear debris samples came only from original auto equipment, a partial relining, and a relining for the car tested on the dyna- l mometer. Alste et al. (1976) also collected random samples of wear debris from an auto repair shop, but apparently from only a few cars at most (a much smaller I sampling than Rohl et al.). I Neither Rohl et al. (1976), Jacko and DuCharme (1973), nor Alste et al. (1976) considered, or tested, brake linings manufactured by dif- I ferent companies, different technical processes, or different compositions in any systematic manner which would be representative of the entire brake lining 1 industry. Hence, there has been no experimental study conducted which can con- 1 firm or refute the supposition that brake linings made by different companies, processes, and compositions may contribute varying amounts of asbestos emissions into the environment. 6.4.2 Emission Quantities 'R1 Table 6.6 gives the estimated annual asbestos emissions for vehicles as computed by Jacko and DuCharme (1973). These figures are based, in part, upon Jacko and DuCharme's figure of less than 1% (~0.2%) asbestos content of emission debris. They also made the following estimations: (1) The total amount of asbestos contained in all of the l automotive brake friction materials sold each year is about 103 million pounds which corresponds to ~118 million pounds prior to grinding and drilling. 1 (2) The total amount of asbestos contained in all automotive clutch friction materials sold each year is about 4.5 million pounds. I 89 fMS\ 062'\6 -....... ~ t::~-r!'-'.t ~ ,.t{~f'-<t --$!!! I ~'"''"''"f "''*-:~~ ~~w ~~ _... - __ - -_....,_...... Table 6.6. Estimated Asbestos Emissions* by Jacko and DuCharme (1973) from Vehicles Total Distribution of Total {lb) Number of Annual Asbestos Vehicles Emissions (lb) Drop-Out Airborne Retention Passenger Cars 96,400,000 60,400 Light Trucks 17,100,000 32,300 Medium Trucks and Buses 2,600,000 16,300 \0 Heavy Trucks 0 Miscellaneous (motorcycles, trailers, etc.) 1,200,000 6,615,000 32,900 16,300 Totals 158,200 Percent of Total 49,470 28,420 14,330 28,920 14,330 135,470 85.6 2,230 940 470 950 470 5,060 3.2 8,700 2,940 1,500 3,030 1,500 17,670 11.2 * Includes both brake linings and clutches 'TI -e3n: -0 CJ) N ..... j (3) The combined total of brake and clutch friction material worn away annually is 123.6 million pounds (117 (brakes) + l 66 (clutches) = 123.6). Assuming an average asbestos content of 60%, the amount of asbestos worn away as friction material wear debris is ~74 million pounds. Based upon available data from other sources (Clifton, 1975; U.S. Bureau of the Census, 1972, 1975), the estimations made above are quite I reasonable and are probably good figures to use in emission computations. l Table 6.7 lists the estimated asbestos emissions using the Rohl et al. (1976) figure for the asbestos content of wear debris. Computations l were made using the same assumptions and method as Jacko and DuCharme (1973); the only variation is the use of different asbestos content percentages. Rohl ~ al. (1976) arrived at an average asbestos content figure of 3-6% (therefore, a median of 4.5% is listed in Table 6.7) and high-low values of 2-15%. A comparison of Table 6.6 and 6.7 reveals that the total annual asbestos emissions reported in Table 6.7 (4.4% median) is nearly 22 times higher than the total reported in Table 6.6. The focal point of the difference is the percentage of asbestos which survives in the wear debris. Jacko and DuCharme (1973) determined that approximately 3% of the asbestos emission become airborne. Based upon sample concentrations collected at freeway exits, Alste et al. (1976) concluded that only a small fraction of the total dust formed becomes airborne, which is consistent with Jacko and DuCharme. 6.4.3 Human Exposure to Asbestos Emissions During Brake Lining Maintenance and Repair In the United States, an estimated work force of at least 900,000 auto mechanics and garage workers is potentially exposed to asbestos in 91 FMSI 06218 :.:.~.:..."'".J:.1.t - """~ w~~ !?- ~~W11, r.t:'4,.t...C!;Yt; ~~~~11 "-V>'J! """"'~~ ~ ~' - - - - -~ .._ Table 6.7. Estimated Asbestos Emissions from Vehicles Using Rohl et al. (1976) Figures for Asbestos Content of Wear Debris Asbestos Content of Wear Debris Total Annual Asbestos Emissions (lb) Distribution of Total (lb) Drop-Out Airborne Retention 2% (low) 1,520,000 1,300,000 49,000 171,000 \D 15% (high) 11,400,000 9,800,000 360,000 1,280,000 N 4.5% (median of average 3,420,000 2,930,000 110,000 380,000 3-6%) "'T1 !e-n: 0 Q) N ~ CD the servicing of both brake and clutch linings (Rohl et al., 1976). Measurable concentrations of asbestos fiber have been observed and reported in the work environment of workmen involved with brake and clutch linings maintenance and repair (Hickish and Knight, 1970; Hatch, 1970; Boillat and Lob, 1973; Rohl et al., 1976). When a vehicle is brought into a repair shop for brake lining ( inspection or replacement, the wheel is removed and the loose dust is removed from the drums and back plates, generally by means of a compressed air jet. A 1 cloud of dust is produced by this air jet Hhich is visible for several minutes. Table 6.8 lists the fiber concentrations which were measured as a result of the dust cloud by the most relevant study (Rohl et al., 1976) to American standards l of exposure; also given are concentrations measured for common truck servicing operations. I The result of the Rohl et al. (1976) study indicates that it is common for OSHA asbestos-fiber concentration standards to be exceeded during brake cleaning operations. It should be noted that fiber counts made during this study were in accordance with procedures adopted by OSHA. Essentially, the analysis consists of counting fibers 5 to 100 ~m using phase contrast microscopy at a magnification of 400X. Section 6.4.1.2 revealed that most of asbestos present in wear I debris is much smaller than 5 ~m. Rohl ~ al. (1976) estimated that 80% of the 1 fibers present are shorter than 0.4 ~m. Accepting these results, it is obvious that the asbestos exposure during brake servicing may be a great deal higher than is indicated by OSHA test standards. l 93 FMSI 06220 Table 6.8. Asbestos Concentration During Automobile and Truck Brake Service* (Roh1 et al., 1976) 1 Fiber Concentration (fibers/ml) Number Distance of Operation (ft) Samples Mean Range Auto - Blowing dust out of 3-5 l brake drums with compressed air 5-10 10-20 4 16.0 6.6-29.8 3 3.3 2.0-4.2 2 2.6 0.4-4.8 ! Truck - Renewing used linings by grinding 3~5 10 3.8 1.7-7.0 t Truck - Beveling new linings 3-5 5 37.3 * Fibers 5-100 vm in length, counted by optical microscopy. 23.7-72.0 1 6.5 Alternatives to Asbestos as a Friction Material 6.5.1 The Role of Asbestos in Friction Linings Originally, automotive brake linings were made from a cotton textile material which was impregnated with drying oils and cured to form a strip of material which was flexible, conformable, and mechanically very strong. The main purpose of the drying oil was to protect the cotton from attack by atmospheric oxygen, which, even at the temperatures reached by early brakes, would have resulted in burned cotton had its surface been exposed to the air. As brake operating temperatures increased, it was found that cotton started to degrade and lose its strength even though still protected from oxygen attack. In other works, the cotton suffered thermal degradation instead of oxidative degradation (Hatch, 1970). 94 FMSI 06221 1 l Around 1910, a technological breakthrough was achieved when it l was discovered that asbestos could be woven and used to replace cotton because asbestos neither burns nor loses its strength below about 500C. When braking operations became more severe, in the 1940's, brake linings began to be manufactured by moulding powdered resins with short asbestos fibers. This made possible the inclusion of various property modifiers to aid in the braking 1 operations (Hatch, 1970). As described in Section 6.2, this is the current method of brake lining manufacture. t Any alternative material to asbestos in brake linings has to compete with asbestos's properties of strength, high temperature protection, insulation, and good frictional properties. 6.5.2 Alternatives in Brake Linings At this time, there are no commercially available, asbestos-free brake linings intended for use in automobiles with drum brakes (Aldrich, 1977; Rosenburg, 1977). This is not the case when considering disc brake pads, as will be explained later. Currently, nearly all of the major brake lining manufacturers are engaged in research and testing programs to develop asbestosfree drum brake linings for automobiles; commercial success has not been achieved. It should be noted that, if by "alternative" we mean a new or better fiber which might shortly be available as a replacement for asbestos in conventional brake 1. linings, the chances are actually quite remote. The possible asbestos alternatives which are being tested and l considered are discussed below (Hatch, 1970; Aldrich, 1977; Rosenburg, 1977): (1) Glass Fiber - overall strength is lower than that of asbestos, but strong enough for friction material applications. Unfortunately, at the temperatures I reached by braking operations, glass fiber melts, even in depth below the operating surface. l 95 FMSI 06222 l (2) Steel Wool- compared to asbestos, the overall strength is lower and the cost is much higher. In addition, the material hardness of steel wool damages the brake drums. I (3) Mineral Wools - overall strength is very low and brittle to the extent of limiting mixing processes. (4) Carbon Fiber - the main properties of carbon fibers are generally good, but still somewhat inferior to asbestos. A major consideration is the cost, which is a great deal more than asbestos. (5) Sintered Metals and Cermets - these materials are now I being used to manufacture brake linings for railroad cars and airplanes. Eventually, these materials may be developed into practical applications for automo- 1 biles. At this time, the wear-resistance is not good enough for automotive uses and the cost is too high. 1 There are two good reasons why the industry is attempting to develop asbestos-free products. First, there is the possibility of a govern- mental ban on asbestos applications which emit asbestos fibers into the atmos- phere. And secondly, asbestos-free manufacture would eliminate the need for asbestos-environmental control devices in the workplace and would eliminate a health hazard to employees, thereby eliminating a sub'stantial expense. Some American brake lining manufacturers are currently maneuvering around the second reason above by establishing manufacturing plants in foreign countries whose pollution regulations are much less stringent than in the United States. The i friction products containing asbestos can then be imported into the U.S. 6.5.3 Alternatives in Disc Brake Pads It is purely fortuitous that the friction materials used in disc brakes are designed to a stronger shape than in drum linings; that is, more or less square or circular pads of considerable thickness are supported by a metal plate of adequate thickness. Therefore, the friction material does not have to stand up to handling during assembly, does not have to withstand riveting, and f 96 l FMSl 06223 could, from the point of view of bulk mechanical strength alone, be made without a high loading of fibrous reinforcement of any kind. There remains, however, thermal shrinkage and thermal shock, and in order to prevent the formation of tensile cracks normal to the operating surface, a percentage of asbestos fibre is still retained (Hatch, 1970). t Nevertheless, it cannot be said that the use of asbestos in disc I brake pads remains a technical necessity (Hatch, 1970); in fact, commercially available disc pads have been developed for automotive uses which do not use asbestos (Aldrich, 1977). Table 6.. 9 lists a typical composition for this asbestos-free disc pad. Cost of the asbestos-free pad is somewhat higher than t the asbestos pad. Table 6.9. Asbestos-Free Composition of a Disc Brake Pad (Aldrich, 1973) (vol. %) Carbon Iron Powder Steel Fiber Phenolic Resin 45 25 10 20 (manufactured by common methods) 6.5.4 Alternatives in Clutches Borg-Warner Corporation, a major manufacturer of clutches, is currently engaged in the testing of asbestos-free friction materials intended for use in clutches (Rosenburg, 1977). The asbestos-free materials being tested f have been developed by the major friction-material producers such as Raybestos- I }1anhattan and Abex. To date, none of the alternatives tested have been as good as asbestos. l 97 FMSI 06224 6.6 Summary and Conclusions for Asbestos Friction Applications (1) Chrysotile asbestos fiber is a major component of brake and clutch lining friction materials. Asbestos is used because it imparts strength, ,good friction properties, can withstand high temperatures, and is a good insulator. (2) The annual U.S. demand for asbestos in friction products has 'historically ranged from 65-80 thousand short tons, or approximately 9% of the total U.S. asbestos demand. Projections calculated from 1972 figures released by the U.S. Bureau of the Census indicate that the shipment value of all asbestosfriction products is currently about $300 million. (3) At present, nearly 118 million pounds (59 thousand short tons) of chrysotile asbestos are consumed annually for fabrication of automotive brake linings. (4) Asbestos usually used in friction materials is chrysotile from Quebec and Vermont. Length grades 5 and 7 account for nearly 83% of the total use. (5) Approximately 35 corporations operating a total of 44 plant establishments are currently engaged in manufacturing asbestos-friction material products. (6) The eight largest corporations (headed by Raybestos-Manhattan, Bendix Corporation, and Abex Corporation) control from 75-85% of the asbestosfriction material market. (7) Several different process technologies are used to manufacture I asbestos brake linings and clutch facings. Manufacture can be accomplished by a molding process, in a dry or wet-mix state, or by a woven process. I 98 FMSI 06225 r J (8) A wide variety of ingredient compositions are used for the fabrication of automotive brake linings. In addition to the 30-60% typical asbestos content, at least 43 different inorganic and organic compounds have l been listed for use by previous publications and patent literature, as property modifiers and binders. 1 (9) It may be reasonable to speculate that asbestos emissions resulting from autowotive brake lining use may vary in concentration, depending t upon the ingredient composition and the process method used to manufacture the '1 individual lining. (10) Among the studies which have examined asbestos emissions or wear debris from brake linings, the best appear to be Rohl et al. (1976), Jacko and DuCharme (1973), and Alste ~ al. (1976). These studies utilized different I methodologies and arrived at different results. Rohl et al. (1976) examined random samples of brake lining wear debris from automobiles used under real-life conditions and determined, by X-ray diffractometry, that 2-15% of the wear debris was asbestos. Jacko and DuCharme (1973) produced samples of wear debris by means of laboratory simulation utilizing a car on a dynamometer, with specially designed collection apparatus, and concluded, by electron microscopy, that the wear debris contained, on average, only 0.2% asbestos. Using real-life samples examined by electron microscopy and electron diffraction, Alste et al. (1976) concluded that the major effect of braking appears to be in separating bunches of fibers and reducing their average length, but not in altering their crystal structure. This disparity in results, computed by'very qualified re- i searchers, leads to the conclusion that additional work is required in determining a more consistent evaluation of asbestos in wear debris from brake I linings in terms of content percentage. 99 F~S\06226 (11) There has been no experimental study conducted which can confirm or refute the supposition that brake linings made by different companies, processes, and compositions may contribute varying amounts of asbestos emissions into the environment. This supposition is offered as a suggestion which may be beneficial in the explanation of the different results obtained by Rohl et al. (1976), Jacko and DuCharme (1973), and Alste et al. (1976). ( (12) According to Jacko and DuCharme (1973), the total asbestos contribution to the environment as a result of brake and clutch lining wear is 1 nearly 158,000 lbs/yr, of which 5,060 lbs/yr is airborne. Utilizing the results obtained by Rohl et al. (1976) for asbestos content of wear debris, we can [ calculate that the total environmental contribution, on average, would be 3,420,000 lbs/yr, of which 110,000 lbs/yr would be airborne. Obviously, the 1 u. differences are significant. I (13) A very high percentage of the asbestos emitted in wear debris is shorter than 5 ~m in length. In fact, Rohl et al. (1976) found that nearly 80% of this asbestos is shorter than 0.4 ~m. This is an extremely important consideration when dealing with exposure to workers, such as brake service mechanics, who come into direct contact with this airborne wear debris. OSHA standards count only fibers from 5-100 ~m in length; therefore, any measurements made by OSHA standards would seriously underestimate the asbestos exposure to the '"orkers. Rohl ~ a1. found that even under OSHA test standards. asbestos fiber concentrations would periodically exceed OSHA regulations during brake maintenance and repair. 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