PRELIMINARY AIR POLLUTION SURVEY OF ASBESTOS A LITERATURE REVIEW U. S. DEPARTMENT OF HEALTH, EDUCATION, AND WELFARE Public Health Service Consumer Protection and Environmental Health Service ------- PREFACE This document represents a preliminary literature review which is being used as a basis for further evaluation, both internally by the National Air Pollution Control Administration (NAPCA) and by contractors. This document further delineates present knowledge of the subject pollutant, excluding any specific conclusions based on this knowledge. This series of reports was made available through a NAPCA contractual agreement with Litton Industries. Preliminary surveys include all material reported by Litton Industries as a result of the subject literature review. Except for section 7 (Summary and Conclusions), which is undergoing further evaluation, the survey contains all information as reported by Litton Industries. The complete survey, including section 7 (Summary and Conclusions) is available from: ------- PRELIMINARY AIR POLLUTION SURVEY OF ASBESTOS A LITERATURE REVIEW Ralph J. Sullivan Yanis C. Athanassiadis Litton Systems, Incorporated Environmental Systems Division Prepared under Contract No. PH 22-68-25 U.S. DEPARTMENT OF HEALTH, EDUCATION, AND WELFARE Public Health Service Consumer Protection and Environmental Health Service National Air Pollution Control Administration Raleigh, North Carolina October 1969 ------- The APTD series of reports is issued by the National Air Pollution Control Administration to report technical data of interest to a limited reader- ship. Copies of APTD reports may be obtained upon reciuest, as supplies permit, from the Office of Technical Information and Publications, National Air Pollution Control Administration, U.S. Department of Health, Education, and Welfare, 1033 Wade Avenue, Raleigh, North Carolina 27605. National Air Pollution Control Administration Publication No. APTD 69-27 11 ------- FOR EWORD As the concern for air quality grows, so does the con- cern over the less ubiquitous but potentially harmful contarrii— nants that are in our atmosphere. Thirty such pollutants have been identified, and available information has been summarized in a series of reports describing their sources, distribution, effects, and control technology for their abatement. A total of 27 reports have been prepared covering the 30 pollutants. These reports were developed under contract for the National Air Pollution Control Administration (NAPCA) by Litton Systems, Inc. The complete listing is as follows: Aeroallergens (pollens) Aldehydes (includes acrolein and formaldehyde) Ammonia Arsenic and Its Compounds Asbestos Barium and Its Compounds Beryllium and Its Compounds Biological Aerosols (microorganisms) Boron and Its Compounds Cadmium and Its Compounds Chlorine Gas Chromium and Its Compounds (includes chromic acid) Ethylene Hydrochloric Acid Hydrogen Sulfide Iron and Its Compounds Manganese and Its Compounds Mercury and Its Compounds Nickel and Its Compounds Odorous Compounds Organic Carcinogens Pesticides Phosphorus and Its Compounds Radioactive Substances Selenium and Its Compounds Vanadium and Its Compounds Zinc and Its Compounds These reports represent current state—of—the—art literature reviews supplemented by discussions with selected knowledgeable individuals both within and outside the Federal Government. They do not however presume to be a synthesis of available information but rather a summary without an attempt to interpret or reconcile conflicting data. The reports are 111 ------- necessarily limited in their discussion of health effects for some pollutants to descriptions of occupational health expo- sures and animal laboratory studies since only a few epidemic— logic studies were available. Initially these reports were generally intended as internal documents within NAPCA to provide a basis for sound decision—making on program guidance for future research activities and to allow ranking of future activities relating to the development of criteria and control technology docu— ments. However, it is apparent that these reports may also be of significant value to many others in air pollution control, such as State or local air pollution control officials, as a library of information on which to base informed decisions on pollutants to be controlled in their geographic areas. Addi- tionally, these reports may stimulate scientific investigators to pursue research in needed areas. They also provide for the interested citizen readily available information about a given pollutant. Therefore, they are being given wide distribution with the assumption that they will be used with full knowledge of their value and limitations. This series of reports was compiled and prepared by the Litton personnel listed below: Ralph J. Sullivan Quade R. Stahl, Ph.D. Norman L. Durocher Yanis C. Athanassiadis Sydney Miner Harold Finkeistein, Ph.D. Douglas A. Olsen, PhOD. James L. Haynes iv ------- The NAPCA project officer for the contract was Ronald C. Campbell, assisted by Dr. Emanuel Landau and Gerald Chapman. Appreciation is expressed to the many individuals both outs ide and within NAPCA who provided information and reviewed draft copies of these reports. Appreciation is also expressed to the NAPCA Office of Technical Information and Publications for their support in providing a significant portion of the technical literature. V ------- ABSTRACT Inhalation of asbestos may cause asbestosis, pleural or peritoneal mesothelioma, or lung cancer. Mesothelioma is a rare form of cancer which occurs frequently in asbestos workers. All three of these diseases are fatal once they become established. The dose necessary to produce asbestosis has been estimated to be 50 to 60 million particles per cubic foot—years. No information is available on the dose necessary to induce cancer. Random autopsies of lungs have shown “asbestos bodies” in the lungs of one—fourth to one—half of samples from urban populations. Thus, the apparent air pollution by asbestos reaches a large number of people. Animals have been shown to develop asbestosis and cancer after exposure to asbestos. No information has been found on the effects of asbestos air pollution on plants or materials. The likely sources of asbestos air pollution are uses of the asbestos products in the construction industry and asbestos mines and factories. Observations in Finland and Russia indi- cate that asbestos does pollute air near mines and factories. However, no measurements were reported of the concentration of asbestos near likely sources in the United States. A concentra- tion in urban air of 600 to 6,000 particles per cubic meter has been estimated. Bag filters have been used in factories to control v ii ------- asbestos emissions; the cost of this type of control in a British factory was approximately 27.5 percent of the total capital cost and about 7 percent of the operating cost. No information has been found on the costs of damage resulting from asbestos air pollution. No satisfactory analytical method is available to determine asbestos in the atmosphere. viii ------- LIST OF TABLES 1. Deaths of Asbestos Insulation Workers in New York, 1963—67 • • . . . . . . 16 2. Distribution of “Asbestos (Ferruginous) Bodies” in Lungs in Pittsburgh . . . . . . . . 20 3. Type and Number of Tun rs Induced by Intrapleural Inoculation of S.P.F. Rats with Asbestos . . . . . 22 4. Dust Counts in Asbestos Mines and Mills in South Africa, 1947 29 5. Cancer of the Lung Among Asbestos Workers 62 6. “Asbestos Bodies” in Consecutive or Random Autopsies 64 7. Composition and Properties of Asbestos . . . . . . 66 8. World Production of Asbestos . . . . 69 9. The Production and Apparent Consumption of Asbestos in the United States . . . . 71 10. Regional Distribution of Asbestos Mining and Processing . . . . . . . . . . . . . . 72 11. Asbestos Mines in the United States, 1966 . . . . 73 12. Apparent Asbestos Consumption, 1965 . . . . . . . . 74 13. Proportion of Asbestos in Various Asbestos Products 75 14. Quantity and Value of Asbestos Input by Industry, 1963 . . . . . . . . . . . . . . . . . . . . . . . 75 15. Population Groups with Occupational and Environmental Exposure to Asbestos 76 16. Asbestos Control Equipment 77 17. Analysis of Asbestos and Asbestos Products Exports and Imports . . . . . . . . . 78 18. Selected Statistics for the Asbestos I4anufacturing Industry 79 ix ------- LIST OF TABLES (Continued) 19. Selected Statistics for the Asbestos Products In— dustr r . . . . . . . . . . . . . . . . . . . . . . 80 20. Asbestos Uses . a a a • • • • . . . 81 21. 1967 List of Manufactured Asbestos Products . . . 84 22. Asbestos Product Manufacturing Plants, 1963 . . . 86 23. Penetration of Fibers Through Nasal Hairs . . . . 93 24. Particle-Mass Relationship of Asbestos as a Function ofFiberLength . . . . . . . . . . . . . . . . . 93 LIST OF FIGURES 1. Comparison of Trends in World Production and U.S. Consumption of Unmanufactured Asbestos . . . . . . . 30 x ------- CONTENTS FOREWORD ABSTRACT 1. INTRODUCTION. 1 2 . EFFECTS . . . . . . . 3 2.1 Effects on Humans . 3 2.1.1 Asbestosis . . . . . . . . . . . . . . . 4 2.1.2 Pleural Calcification and Plaques . . . 6 2.1.3 Cancer . . . . . . . . . . . . . . . . . 7 2.1.3.1 Cancer of the Lung 7 2.1.3.2 Mesothelioina of the Pleura and Peritoneum . . . 11 2.1.3.3 Other Cancers . . . . . . . . . 15 2.1.3.4 Synergism . . . . . . 15 2.1.4 “Asbestos Bodies” . . . . . . . . . . . 17 2.2 Effects on Animals . . . . . . . . . . . . . . 20 2.2.1 Commercial and Domestic Animals . . . . 20 2.2.2 ExperimentalAnimals. . . . . . . . . . 21 2.3 Effects on Plants 24 2.4 Effects on Materials . . . . . 24 2.5 Environmental Air Standards . . . . . 24 3. SOURCES 26 3.1 NaturalOccurrence 26 3 . 1 . 1 Me s . . . . . . . . . . . . . . . . . 26 3.2 Production Sources . . . . 29 3.3 Product Sources . . . . . . . . . . . . . . . . 31 3.4 Environmental Air Concentrations . . . . . . . 33 4 . ABA,T E ’4ENT . . . . . . . . . . . . . . . . . . . . . 3 5 5. ECONOMICS . . . . . . . . . . . . . . . . . . . . . 37 6. METHODS OF ANALYSIS 38 R ‘ERENCES . . . . . . . . . . . . . . . . . . . . 41 2-\PPENDIX . . . . . . . . . . . . . . . . . . . . . . 61 APPENDIX B . . . . . xi ------- 1 1. INTRODUCTION Asbestos is a general name given to a variety of useful fibrous minerals. The value of asbestos ensues from the indestructible nature of products fabricated from the various grades of mineral fibers. The major asbestos minerals are chrysotile, crocidolite, amosite, and anthophyllite, while tremolite and actinolite are considerably less important. Over 90 percent of the asbestos is chrysotile. The United States uses about one—fourth of the world production of this substance, practically all imported from Canada and Africa. Inhalation of asbestos dust has long been recognized as 161,165 an industrial hazard. Early in this century, exposure to high concentrations of the fibrous dust was causally associated with asbestosis. In 1935, evidence began to accumulate that cancer of the lung is also associated with inhalation of asbestos. 55 More recently, certain rare cancers, pleural mesotheliomas and peritoneal mesotheliomas, have been associated with inhalation of asbestos fibers by asbestos workers. 176 Heirnann 92 states that “The finding of several such rare tumors in any given group makes that group suspect of having special and distinct environmental characteristics, in this case, exposure to asbestos dust.” Nonoccupational environmental exposure to asbestos was found as early as 1927 when Haddow 81 reported finding so- called “asbestos bodies” in the lungs of a person living near ------- 2 an asbestos factory. Since then, several investiga- tors’ 21 ’ 175 ’ 186 ’ 202 ’ 226 have reported finding neighborhood cases. The subject of nonoccupational environmental exposure to asbestos assumed a new dimension beginning with the re- ports of Thomson and his colleagues. 213216 After examining the lungs in consecutive autopsies, they found that approxi- mately one-fourth of the populations in both Capetown, South Africa, and Miami, Fla., have “asbestos bodies” in their lungs. Other investigators have confirmed that one—fourth to one—half of the population in Pittsburgh, 42 San Francisco, 43 Milan, 67 Glasgow, 188 blew York, 195 Montreal, 7 Jerusalem, 184 167 82 ,, Finland, and Sweden have asbestos bodies” in their lungs. These findings indicate that either these asbestos particles or other particles that resemble asbestos in many ways 1 in- cluding the way in which the body reacts to them, are being inhaled either with the ambient urban air or through direct exposure to asbestos. ------- 3 2. EFFECTS 2.1 Effects on Humans Asbestosis (a diffuse pulmonary fibrosis), pleural calcification, pleural plaques, lung cancer, arid pleural and peritoneal mesotheliomas can result from exposure to asbestos. Asbestos bodies are commonly found in the lungs of persons exhibiting these complications. Diagnosis of any of these or finding “asbestos bodies” in the lungs signifies the need to review the case history for previous asbestos exposure. Surveys of people living or working near asbestos mines and factories have revealed that many nonoccupational cases of asbestosis and mesothelioma have occurred either from the polluted air or from asbestos carried home on the workers’ 175, 176,178 clothing. However, in many cases no exposure to asbestos can be established. The fate of the asbestos fiber once it is inhaled* and deposited in the lung is still questionable. The short fibers, <0.5 in length, have been pathologically ignored, probably because they are much too narrow to be visible under a light microscope. The longer fibers which are encrusted in an iron— bearing protein (asbestos bodies) become easily visible. 228 172 Wagner and Skidmore and Morris et al have shown that rats which have inhaled asbestos lose the asbestos (probably the short fibers) from their lungs. The biological half—life *A discussion on respirable fibers is presented in Appendix B (page 92). ------- 4 for asbestos appears to be 20 to 90 days, depending on the mineral type. Some of the fibers are removed by phagocytosis to the lymph nodes. 2.1.1 Asbestosis Among asbestos workers, evidence of pulmonary asbestosis is common. This condition results in a diffuse fibrosis, usually in the lower lobes of the lung. Pulmonary asbestosis has been called a monosymptomatic disease, with dyspnea as the main complaint. 197 The British Occupational Hygiene Society 136 has reported that basal rales are the first symptoms of asbes— tosis. Asbestosis usually develops after long exposure to high concentrations of asbestos dust. The risk varies directly with the length of exposure and the dust concentration. Following continued exposure to high concentrations of dust, asbestosis may develop fully in 7 to 9 years and may cause death as early as 13 years from onset of exposure. The common exposure period before recognition of asbestosis (as observed among asbestos workers) is 20 to 40 years, with death following about 2 to 10 years later. Once established, asbestosis progresses even after the exposure to dust ceases: illness or death can occur long after exposure to concentrations not producing immediate effects. 197 The prolonged latency period between exposure and the first signs of asbestosis makes it difficult to establish dose— time relationships. Cooper 43 suggested that a time—weighted ------- 5 average concentration of asbestos fibers of 5 mppcf* is too high. He cites Wells’ 234 idea that multiplying average counts by years of exposure provides a rough guide to the total dose allowable. After 50 to 60-mppcf—years, workers began to show evidence of asbestosis. At an average concentration of 5 mppcf, this total allowable dose would be reached in 10 to 12 years. Unfortunately, dust concentrations have been infre- quently reported and measurements have been hampered by the 153 191 varied nature of the sources. Marr and Selikoff et al. have reported that insulation workers are exposed to dust concentrations below 5 mppcf, yet have exhibited a high prevalence of asbestosis. Thus, Cooper’s argument is strengthened. In 1946, there were about 700 cases of asbestosis in Germany among a total of approximately 8,000 employees in the 108 235 asbestos industry. Wegelius found 125 cases of asbestosis of the lung in X—ray examinations of 476 asbestos workers in one company in Finland. Of 132 asbestos workers examined by Bohme, 26 29 percent showed X—ray evidence of asbestosis. The occurrence of asbestosis in members of this worker group rose with the duration of the employment: 5 percent in workers exposed to asbestos for less than 3 years; 56 percent for those employed for 5 to 10 years, and 79 percent for those with over 10 years’ exposure. A similar morbidity of 80 percent among *5 million particles per cubic foot based on total dust count and 8—hour--day, 40—hour—week exposure. ------- 6 English asbestos workers with over 20 years of employment was 165 177 reported by Merewether and Price in 1930. Noro noted that the incidence of asbestosis was 65 percent in 167 asbestos 197 workers studied by X—ray. Selikoff j. investigated 1,522 asbestos insulation workers in the New York—New Jersey metropolitan area. Among 392 individuals examined more than 20 years from the onset of exposure, X—ray evidence of asbestosis was found in 339. In half of these, the asbestosis was moderate or extensive. In individuals with less than 20 years of exposure, radiological evidence of asbestosis was less frequent and when present, was much less likely to be extensive. 2.1.2 Pleural Calcification and Plagues Pleural calcification resulting from exposure to asbestos 120 is usually bilateral and affects the parietal pleura. 193 Selikoff stated that bilateral pleural calcification involving the diaphragm is diagnostic of asbestosis. This pleural calci— 117 fication can be readily identified by X—ray. Kiviluotol2O discovered 499 cases of pleural calcifica- tion during a community X—ray survey of 6,312 adults in the Kuusjari commune in Finland. In Ilomantsi commune he found no such calcification among 7,101 adults. He observed that the Kuusjari commune contained an asbestos mine and suggested that these people had been subject to a localized environmental asbestos expc ure. This investigator’ 21 also observed 77 cases of pleural plaques out of 35,000 routine chest X—rays. The case histories of these 77 revealed that 52 had previous ------- 7 exposure to asbestos either in the home or in their occupations, where they handled asbestos products. Of the other 25 persons, 16 were questioned and no previous asbestos exposure could be ascertained. Raunio 186 continued the study Sand found 1,516 adult cases of pleural calcification from 633,201 X—rays taken in 13 Finnish towns and 106 rural conununes. In Tuusniemi commune, where an asbestos quarry is located, pleural calcifi- cation was found in 9 percent of the population; in urban populations it was found in 0.7 percent of the people; and in rural areas calcifications were found in only 7 out of 265,273 people examined (0.002 percent). However, Meurman - 67 found the pleural plaques were common (39.3 percent of his cases) in all Finland. Approximately 2.8 percent of the agricultural workers in Czechoslovakia 105 and Bulgaria 238 have also been shown to have appreciable pleural calcification. In Bulgaria the soils worked by the farmers contained asbestos; even stone fences were made of outcrops of anthophyllite mineral. However, in Czechoslovakia no asbestos or known exposure to asbestos was found. After examining children living in the city of Asbest in the Soviet Union, Bobyleva etal. 24 ’ 25 concluded that they were suffering from impaired health caused by air pollution from asbestos plants. 2.1.3 Cancer 2.1.3.1 Cancer of the Lung The most common complication of asbestosis is cancer of the lung. However, cancer of the lung apparently induced by ------- 8 asbestos may appear unaccompanied by asbestosis. The association of lung cancer with exposure to asbestos dust has been the subject of many investigations in the second quarter of this century. In 1935, Lynch and Smith’ 49 in the United States described lung cancer found during autopsy of a patient with asbestosis. According to Hornburger t s data, 101 over a 20—year period eight cases of asbestosis were found in 4,137 autopsies at the medical school of Yale University. Of these eight asbestosis cases, four were associated with lung cancer (50 percent). In contrast, lung cancer was found in only two (12 percent) of 17 cases of silicosis. Lynch and Cannon 147 in 1949 found lung cancer in only three cases (7.5 percent) of 40 patients with asbestosis. Gloyne 71 in 1951 reported that according to autopsy data for the London Hospital of chest Diseases, lung cancer was observed in 14 percent of the 121 patients with asbestosis, but in only 6.9 percent of those with silicosis. Usually, the lung cancer incidence in men is four to six times higher than in women, but among patients with asbestosis it is only twice as high for men. This has been confirmed by Bohlig, Jacob, and Kalliabis. 29 They note that among women working in the asbestos industry, lung cancer is observed at an earlier age than among the rest of the population. In his review, Behrens 19 reported 44 cases of lung cancer (14 percent) in 309 autopsies of patients with asbestosis. After examining ------- 9 the data of various authors, Isselbacher et al. 111 reported that of 603 persons with asbestosis, lung cancer was found in 83 (13.8 percent) at autopsy. Hueper 108 and Do11 record an even higher percentage (15 percent). Doll emphasizes that the majority of those who died had worked under conditions of high dust content in the air. Braun and Truan 33 found lung cancer in 12 (three cases were not conclusive) of 187 workers in the Canadian asbestos industry who had died. Boehme 26 reported 74 patients with asbestosis; lung cancer was found in six of these. The average age of the patients was 53; the average period from the beginning of work to death was 28 years. Kea1 114 points out that of 30 patients with asbestosis, 14 (47 percent) died of lung cancer and 10 from carcinoma of the peritoneum or ovaries. Some additional statistics on the association of lung cancer with asbestos workers are listed in Table 5 in the Appendix. Cancer of the lung produced by asbestos needs further study. The latent period between exposure and evidence of carcinoma may be even longer than for asbestosis. Nothing is known about the dose—time relationship. Cases of lung cancer have been observed when only a very short exposure or no exposure to asbestos was known. Furthermore, the low number of “asbestos bodies” observed in one—fourth to one—half of the urban population may be sufficient to cause cancer. Because ------- 10 the long “asbestos bodies” remain in the lungs, a person who has inhaled asbestos may carry the potential (for the rest of his life) to develop carcinoma of the lung. Moreover, it has not been determined whether more than one fiber is necessary to induce a malignant tumor. Cox 42 has suggested that the probability of cancer induction is proportional to the nunther of asbestos fibers, number of susceptible cells, the concen- tration of carcino ens on the fibers, and the time from exposure. Why asbestos is carcinogenic is not clearly understood. At least three hypotheses have been advanced; (1) That the fibers act as a physical irritant which after 20 to 30 years of constant irritation induces a tumor. (2) That the fibers contain small amounts of carcinogens—— such as benzo(a)pyrene, nickel, and chromium——which are eluted from the fibers by the serum in the lungs. These carcinogens then produce the cancer. Harington and Roe 88 have shown that (a) chrysotile contains little or no benzo(a)pyrene, but about 100 ig of chromium per g of fiber and 5,000 ig of nickel per g of fiber; (b) crocidolite contains 0.2 to 24 ig of benzo(a)pyrene per 100 g of fiber and negligible amounts of nickel and chromium; and (c) amosite contains 0.2 to 2.4 -ig of benzo(a)pyrene per 100 g of fiber, 100 iLg of nickel per g of fiber and 15 J g of chromium per g of fiber (see Appendix B, page 92). The authors have not only shown that these agents can be dissolved in the lung serum, but also that airborne fibers can adsorb ------- 11 carcinogens present in the air. In studies of the adsorption of benzo(a)pyrene by asbestos, chrysotile adsorbed 100 percent of benzo(a)pyrene from solution after 48 hours at 37°C, compared with 40 percent for crocidolite and 10 percent for amosite. Harington and Roe suggest that these carcinogens can be adsorbed on airborne fibers. Thus, the fibers become a transporting vehicle to carry a concentrated quantity of carcinogens into the lung. (3) That the fibers accumulate in the lung and are immobilized as “asbestos bodies” which disintegrate after 20 to 40 years. The resulting free particles cause asbestosis or carcinoma of the lung. In addition, Hammond 83 has suggested that asbestos is a cocarcinogen; i.e., it increases the cancer—producing poten- tial of small amounts of some other agent. In a study of asbestos workers, he and his colleagues 199 found cancer of the lung only in cigarette smokers. The number of deaths attributed to cancer of the lung was eight times higher in asbestos workers who smoked cigarettes than in smokers who were not exposed to asbestos (see Section 2.1.3.4). 2.1.3.2 Mesothelioma of the Pleura and Peritoneum Primary tumors of the pleura and peritoneum are so rare that for years they were considered to be pathologic curiosi- ties. In 1960 the first large series of cases of diffuse 229 mesothelioma were reported by Wagner et al. in South Africa. ------- 12 226 In trying to explain this mysterious epidemic, Wagner, noting that “asbestos bodies’ were found in the lungs of some of their patients, obtained detailed life histories of these patients. By 1960, he was able to establish an association with exposure to the Cape of Good Hope asbestos fields, or the industrial use of asbestos, in 32 of 33 patients with histolog- ically proved pleural inesothelioma. The majority of these patients had not actually worked with asbestos but had lived in the vicinity of the mines and mills, and some had left these areas of exposure as young children. The average period between exposure and development of the tumor was 20 to 40 years. By 226 1962, Wagner had diagnosed a total of 87 pleural and two peritoneal mesotheliomas. In only two cases was it impossible to establish a history of exposure to asbestos dust. of these 87 cases, 12 had been industrially exposed and the remainder had been environmentally exposed from living in the vicinity of the mills and dumps. This association between mesothelioma and asbestosis became even more intriguing when i 1955, Bonser 30 described a series of 72 autopsies on patients with asbestosis in which four cases of peritoneal mesothelioma were found. Subsequently, Mancuso and Coulter 152 found five peritoneal mesotheliomas in 1,495 asbestos workers, and Hourihane,’ 02 upon reviewing the necropsy files of the London Hospital from 1917 to 1962, found 34 cases of mesothelioma, half of the pleura and the other half of the peritoneum. All ------- 13 of these patients had pulmonary asbestosis, even though in a few there was no history of exposure to the asbestos dust. In a subsequent study 103 Houril-iane found 74 cases of mesothelioma in a London hospital over a 10—year period. Borow et 3l report that in two years they observed 11 cases of mesothelioma during surgery in New Jersey. These cases, added to six others previously diagnosed by them, totaled 17 cases of mesothelioma, eight of which were peritoneal and nine pleural. They suggest that the high prevalence of these rare tumors in New Jersey can be explained by its close proxim- ity to a major asbestos mill, where a large percentage of all the asbestos fiber mined in North America is converted to coi iercial use. In an attempt to determine whether mesothelioma of the serosal surfaces was related in any way to asbestos exposure in the United States, Selikoff l98 studied 307 consecutive deaths among asbestos insulation workers in the Northeastern United States. They found 10 deaths caused by four pleural and six peritoneal mesotheliomas. In addition, these workers had a high death rate attributed to cancer of the stomach, colon, and rectum. Of the 307 deaths, 40.4 percent were attributed to cancer, 5.5 percent to asbestosis, and 54.1 percent to other causes. In a second study, the investigators reviewed 26 consecutive autopsies of patients with asbestosis, and found four mesotheliomas of the pleura and three of the peritoneum. ------- 14 A series of 83 patients from the London Hospital with a diagnosis of mesothelioma (confirmed by necropsy or biopsy) were studied by Newhouse and Thompson 176 for possible exposure to asbestos. The series consisted of 41 men and 42 women; 27 of the patients had peritoneal and 56 pleural tumors. Although the earliest death recorded from this group was in 1917, only 10 patients died before 1950, while 40 (48 percent) died between 1960 and 1964. In 76 of the 83 cases, full occupational and residential histories were obtained. Forty patients (52.6 percent) had a history of occupational exposure to asbestos or of domestic exposure (living in the house with an asbestos worker). In comparison, only 11.8 percent (9 of 76) of the patients from the same hospital suffering from other diseases had previous exposure to asbestos. There was also evidence that neighborhood exposures may be important. Among those in this study with no history of occupational or domestic expo- sures to asbestos, 30.6 percent of the mesothelioma patients and 7.6 percent of the inpatients with other diseases lived within half a mile of an asbestos factory. Of the 31 patients with occupational exposures to asbestos, only 10 held jobs scheduled under the British Asbestos Regulations of 1931. The interval between first exposure and the development of the terminal illness from mesothelioma ranged between 16 and 55 years. The duration of exposure varied widely, ranging from two months to over 50 years. In 47 patients in this mesothelioma ------- 15 series, lung tissue or sputum was available for examination. In 30 (62.5 percent), either asbestosis or the presence of asbestos bodies was noted. Mesothelioma is now considered a frequent cause of death among asbestos workers. No attempt has been made to summarize the reports of mesothelioma, since they appear almost weekly in the current literature. So far, however, there appear to be few Cases among the general population. Selikoff 198 reviewed 31,652 deaths among the general popula- tion of over 1,048,183 in the United States and found only three cases of mesothelioma. Moreover, he 195 points out that asbestos is not the only cause of mesothelioma: it has also 224 107 been produced by silica and polyurethane. 2.1.3.3 Other Cancers Extrapulmonary cancer has also been noted as a cause of death among asbestos workers. Kogan et , •132 in 1966 reported 14 cases (31.1 percent), 11 women and 3 men. Four of the women died of uterine cancer, two of intestinal cancer, two of breast cancer, arid one of liver cancer. among the men, one died of stomach cancer, another of cancer of the urinary bladder, and a third of cancer of the prostate. Other cases of extra— pulmonary cancer have been cited in Section 2.1.3.2. 2.1.3.4 Synergism While the exact cause of lung cancer or pleural peritoneal mesothelioma induced by asbestos is not known, air pollution by ------- 16 other pollutants may accelerate the morbidity. One form of air pollution which is easily studied in individuals is smoking. Selikoff et al. 199 recently studied the mortality of 370 asbestos insulation workers. In this group 24 men died of lung cancer and all had a history of smoking. (See Table 1 below.) This rate was eight times greater than the expected mortality rate, with age and smoking habits taken into account. TABLE 1 DEATHS OF ASBESTOS INSULATION WORKERS IN NE ’! YORK, 1963_67l99 (By Smoking Habits) Smoking Habits No. of Casesa Observed Deaths Expected Deaths Never smoked regularly 48 0 0.05 History of pipe, cigar— smoking only 39 0 0.13 History of regular b cigarette smoking 283 24 2.98 Total 370 24 3.16 aAll with more than 20 years from Onset of exposure. bIncludes cigarette smokers who also smoked pipes or cigars. The blue asbestos, crocidolite, from South Africa is believed by many 53 ’ 79 ’ 136 ” 40 ’ 209 to be much more carcinogenic than the other minerals of asbestos. Studies in Finland’ indicate that anthophyllite also produces cancer. Wagner, 226 ------- 17 Smith 206 and recently Godwin and Jagatic? 3 reported that they had induced mesothelioma in mice using chrysotile. 76, 78,98—100,113,172,225,228 Moreover, animal experiments have demonstrated that pulmonary complications occur with crocidolite, chrysotile, amosite, and anthophyllite. Some investigators believe that the fiber is not the carcinogenic agent, but rather the vehicle on which the carcinogens are carried to the target tissue. As stated earlier, chrysotile contains the most nickel and chromium of all asbestos minerals, while crocidolite contains the most benzo(a)pyrene. 8789 ” 59 All three of these impurities in asbestos are suspected of being carcinogenic. This knowledge, together with results which indicate carcinogens can be adsorbed from urban air or tobacco smoke, indicate that there may be no necessity to distinguish urban asbestos dust by mineral types. 2.1.4 “ Asbestos Bodies ” As stated earlier, the recent finding of “asbestos bodies” in one—fourth to one—half of the urban population (see Table 6 in the Appendix) has added new impetus to the examination of asbestos as a general air pollutant. An “asbestos body” has been defined as “an elongated golden or reddish—brown structure usually with clubbed ends; the shaft, which often shows a segmented or beaded appearance, is usually straight, but sometimes curvilinear with a tendency toward symmetry; usually it is from 3 to 5 .i in diameter and ------- 18 20 to 100 t in length. The coating contains iron demonstrable by Perle’s stain (Prussian blue reaction), and probably composed of ferritin or ferritin—like material; it may cover the structure completely, masking the central fiber from direct view, or may be incomplete in the central portion of the shaft or in the interstices of the body, revealing an expanse of 220 naked fiber. There is no doubt that the “asbestos bodies” formed in the lungs of the asbestos workers contain asbestos. Stumphius and Meyer 21 ° have investigated the composition of the “kernel” in the “asbestos bodies” removed from deceased shipyard workers (an occupational group with only indirect exposure). They found by electron microscopy and X—ray microanalyses that the “asbestos bodies” did indeed contain some minerals of asbestos. Out of 27 fibers, 17 were classified as serpentine (possibly chrysotile) and 10 as amphibole (possibly crocidolite). But what about the so—called “asbestos bodies” in the lungs of the general population? While these “asbestos bodies” probably contain some asbestos, there is no experimental evidence to date which shows what fractions contain asbestos or whether they contain any asbestos at all. 79 ’ 194 This subject is currently being debated by several investigators. 53 ’ 79 ’ 209 In fact, some object to the use of the term “asbestos bodies” and prefer to call them “ferruginous bodies.” Moreover, Gross 79 et al. have shown that “ferruginous bodies”—which appear identical under the microscope to those formed from asbestos— ------- 19 can be produced from ceramic aluminium silicate, glass fibers, and silicon carbide fibers. However, Thomson 215 claims that a skilled pathologist can tell the difference. This contro- versy should soon be resolved, since both Gross 53 and Selikoff 194 are investigating the composition of the central fiber with the electron microprobe. Generalized contamination with fibrous material is evidenced by the figures in Table 6 in the Appendix. Two other obvious conclusions are that “asbestos bodies” are found more frequently in older people than in younger, and more frequently in men than in women. In none of the aforementioned studies has there been any quantitative count of “asbestos bodies” in the lungs of the general public. In most studies, “asbestos bodies” found were scanty, although in some instances the bodies were numerous. 214 In most of the investigations, the method of Thomson 214 was used (smears taken from basal lobes of the lung were examined and the asbestos bodies counted). Since only about one—half— millionth of a lung is examined, the finding of only one asbestos particle may be extrapolated to mean that perhaps a half-million fibers are present in the lung. 214 In one recent study in Pittsburgh, Utidjian et al. 22 o made an attempt to quantify their results. In this study 98 percent of the 100 lungs examined contained “asbestos bodies” (“ferruginous bodies”). The results are given in Table 2. For comparison they suggested that if those cases with only one “asbestos body” were ignored, then ------- 20 47 percent of the lungs examined contained two or more bodies, (20.5 percent of the women and 60.7 percent of the men). This 47 percent is in substantial agreement with the compar- able 41 percent reported by Cauna 4 ° (see Table 6 in the Appendix) for residents of Pittsburgh. TABLE 2 DISTRIBUTION OF “ASBESTOS (FERRuGIN0us) BODIES” IN LUNGS IN PITTSBURGH 22 ° No. of Mean Fibers/Unit Distribution Sex Cases Age of Lung ( Percent ) Men 1 89 0 2 21 62 1 37 15 64 2—5 27 19 70 >5 34 Total 56 65 100 Women 2 29 0 5 29 57 1 66 8 68 2—5 18 5 64 >5 11 Total 44 60 100 2.2 Effects on Animals 2.2.1 Commercial and fl mestic Animals Kiviluoto 121 reported finding some asbestos bodies in 201 a cow near an asbestos mine. In 1931, Shuster reported finding extensive pulmonary fibrosis in a dog kept for ratting in an asbestos factory. The lungs of the dog also contained some asbestos fibers but no asbestos bodies were found. ------- 21 Peacock and Peacock 182 have studied the effect of asbestos on white leghorn fowl. They tried dusting the birds with asbestos but found that the fibers did not penetrate far into the lung. When the fibers were injected into the lumen of the air sac, an immediate inflammatory reaction occurred, macrophages appeared and engulfed the fibers, and giant cell formation was observed. Four of the 17 chickens examined developed tumors: of the six injected with crocidolite, two developed tumors; of the 10 injected with amosite, only one developed a tumor; and one chicken injected with an unidenti- fied variety of asbestos also developed a tumor. 2.2.2 Experimental Animals Studies with experimental animals have shown that asbestos can induce fibrosis (asbestosis), cancer of the lung, and mesothelioma and can form “asbestos bodies.” Wagner 234 described experiments with rats in which 600 animals were exposed to various minerals of asbestos. The results are given in Table 3. Gross and De Treville 76 made the following observations in studies on rats, hamsters, and guinea pigs. In rats that have inhaled high concentrations (86,000 1g/m 3 ) of chrysotile asbestos fibers for only a few months, minimal fibrotic lesions can be observed in the lungs of all animals. However, this form of asbestosis in rats is nonprogressive. In hamsters that have inhaled chrysotile dust, a fibrosis develops which is ------- TABLE 3 TYPE AND NUMBER OF TUMORS IN] JCED BY INTRAPL JRAL INOCULATION OF S.P.F. RATS WITH ASBESTOS 2 Asbestos Min ra1s Animals Exposed Animals Died Misc. Norimalig. Misc. Tumors Reticulum—cell Sarcomas Mesotheliomas Croc. 1 a 100 19 5 1 1 12 Croc. 100 10 4 6 Arnosite 100 4 1 1 2 Chrysotile 100 25 5 2 18 Silica 100 11 1 1 2 7 Saline Total 100 5 2 1 2 600 — 74 18 3 8 45 a Crocidolite from b Crocidolite with Northwest Cape, South Africa. oil extracted from it. t’J NJ ------- 23 progressive; “asbestos bodies” are also formed. In guinea pigs, the inhalation of chrysotile dust produces fibrotic lesions similar to those observed in rats. The data indicate that the minimum time to produce asbestosis in rats and guinea pigs is 60 to 120 hours at an asbestos dust concentration of 86,000 1g/m 3 . The investigators think the time required is shorter for hamsters. 228 Wagner and Skidmore have shown that asbestos dust tends to accumulate in the alveoli arising directly from the respiratory bronchioles of rats. They also investigated the elimination of asbestos from the lungs as discussed in Section 2.1. Gross and De Treville 76 also observed a decrease in fiber content as the time from end of exposure increased. Holt et al. 98 suggest from their observations on rats that fibrotic lesions in the lungs are caused by asbestos fibers (chrysotile) which are less than 3 p. long. Longer fibers are stored in the lungs as “asbestos bodies;” shorter fibers are removed from the lungs by phagocytosis. After some years, the larger fibers disintegrate, producing a large number of small particles. These small particles are then phagocytosed and produce fibrosis. They also suggest that asbestos is only fibrogenic when it is ingested by phagocytes. Holt j 100 exposed guinea pigs to asbestos dust. After 14 days of exposure to dust, bronchiolitis was observed; after 21 days the damage was very severe, and “asbestos bodies” ------- 24 were observed along with asbestos fibers. After 226 days the lungs of animals dusted for more ti-ian 1,000 hours over a 78— day period developed a wide—spread, progressive fibrosis with only a few asbestos fibers and “asbestos bodies” present in the lung tissue. The experimenters concluded that asbestos fibers too small to be seen under the microscope will produce asbestosis. In order to evaluate the possible distribution of 194,195 asbestos within New York City, Selikoff is now examining the lungs of rats found in the city for asbestos fibers. In a similar investigation carried out in South Africa, wild animals captured near an asbestos mine were examined. However, the small number of “asbestos bodies” found in them precluded any conclusions. 234 2.3 Effects on Plants No information has been found in the literature on the effects of asbestos air pollution on plants. 2.4 Effects on Materials No information has been found in the literature on the effects of asbestos air pollution on materials. 2.5 Environmental Standards Both the American Conference of Governmental Industrial Hygienists 218 and the American Industrial Hygiene Associa- tion ° have recommended an industrial threshold limit value for asbestos dust of 5,000,000 particles per cubic foot ------- 25 (5 mppcf),based on total dust count and on an B—hour day, 40- hour week. This value was recommended by Dreessen etal. 56 after a study of 541 employees in three textile plants using chrysotile. Only three doubtful cases of asbestosis were found in those exposed to dust concentrations of less than 5 mppcf, whereas numerous cases were found above 5 mppcf. 136 Recently, the British Occupational Hygiene Society published its standards for chrysotile. The Society has recommended a maximum accumulated exposure of 2.8 mppcf—years (108 particle—years per rn 3 ). For example, maximum doses of 0.056 mppcf—years (2 x io6 particle—years/rn 3 ) for 50 years, 0.112 mppcf—years (4 x io6 particle—years/rn 3 ) for 25 years, or 0.28 mppcf—years (10 particle—years/rn 3 ) for 10 years are recommended. They have also recommended that dustiness be designated by categories according to the following scheme: Concentration Averaged Over 3 Months Dust Category ( Million Particles/rn 3 ) Negligible 0—0.4 Low .5—1.9 Medium 2.0—10 High Over 10.0 Only fibers longer than 5.0 i in length with a 3:1 length—to—breadth ratio are counted. With these standards the risk of asbestosis maybe reduced to 1 percent; that is, 1 percent of the workers exposed to a dose of io8 particle—years/rn 3 would contract asbestosis. ------- 26 3. SOURCES 3.1 Natural Occurrence Asbestos is a broad term embracing several fibrous minerals. The minerals are divided into two groups: (1) Pyroxenes—chrysotile; (2) Axnphiboles—crocidolite, amosite, tremolite, actinolite, and anthophyllite. Properties of these minerals are listed in Table 7 of the Appendix. Asbestos probably occurs in nearly every country in the world, but only a few of the deposits are commercially valuable. Over 90 percent of the world asbestos production is chrysotile, and Canada is the major source of this mineral for the United States. 93 Table 8 in the Appendix lists the world production. From these figures an estimate of known free— world deposits is possible. It is noteworthy that some soils near asbestos mines contain considerable quantities of asbestos. In Finland, farmers working these high—asbestos—content soils have been observed to suffer from asbestosis) 20 3.1.1 Mines The mining of asbestos in the United States has in- creased 180 percent in the last 10 years. (See Table 9 in th€ Appendix.) This mining may constitute a source of air pollution. A high percentage of the increase in domestic production has been credited to California producers, who accounted for 65 percent of the total output in 1966. Four ------- 27 companies produced chrysotile asbestos fiber: Atlas Minerals Corp. and Coalinga Asbestos Co., Fresno County; Pacific Asbestos Corp., Calaveras County; and Union Carbide Corp., San Benito County. The latter company processed the crude material in a plant at King City, Monterey County, whereas the other producers operated plants near the mine sites. 171 Amphibole asbestos was mined by Powhatan Mining Co. near Burrisville, Yancey County, N.C. Their output increased 171 66 percent during 1966. There are four chrysotile mines in Arizona in the Salt River Valley near Globe. Since these mines are underground, only the waste needs to be considered in connection with air pollution (other than the possible pollution from transporting the mineral). Nearly all of the output from these mines was used in the Cement industry to manufacture asbestos cement and building products: 28 percent was classified as filter fiber and 2 percent as spinning grade; the rest consisted of sand and waste, floats, or other short fibers. Jacquays Mining Corp. operated the Regal and Chrysotile Mines and shipped the ore to a company mill at Globe after hand-sorting the chrysotile. Western Asbestos Manufacturing Co. operated the Phillips Mine, 171 and the Metal Asbestos Corp. the Lucky Seven Mine. In Vermont, the Vermont Asbestos Mines Division of the Ruberoid Co. quarried and processed chrysotile near Lowell in Orleans County. Twenty—four grades were produced for spinning, cement stock, paper stock, and other uses. Some waste rock ------- 28 171 was used for roadstone. Data on these mines are summarized in Tables 10 and 11 in the Appendix. Other deposits of asbestos have been found in Georgia and Maryland. Although no measurements have been made of the asbestos air pollution from mining in the United States, some evidence of the extent of pollution can be drawn from measurements and observations in foreign countries. The extent of air pollution from an asbestos mine in Finland was studied by Laamanen, Noro, and Raunio) 33 They found asbestos dust at distances up to 50 km from the mines, including dust—fall rates ranging from 1.52 g/lOO m 2 /month at 4 km to 34.6 g/l0O m 2 /month at 0.5 km. They concluded that asbestos dust is disseminated from mining and milling areas rather extensively and that the degree of pollution varies according to the distance from the mine or mill and the prevailing winds. Schepers 234 described the dust from asbestos mines and mills in South Africa as dust which “rolled through like a morning mist,” producing “itching skins caused by asbestos adhering to our clothes. Even the food at the local hotel was gritty with dust.” Sluis—Cremer 202 reports dust counts in asbestos mines and mills of South Africa as listed in Table 4. He pointed out that living quarters near the mines were polluted with asbestos and that the main source of pollution was airborne asbestos ------- 29 blown off dumps and roads made from the mine tailings. TABLE 4 DUST COUNTS IN ASBESTOS MINES AND MILLS IN SOUTH AFRICA, 1947202 Location Dust Count, mppcf (mppm 3 ) Mines Mill - Northwest Cape Province Transvaal 2.8—24 (100—840) 2.3—6.5 (80—228) 10—55 (360—1920) 4.6—20 (162—720) 3.2 Production Sources World production of asbestos during the period 1956 to 1967 increased at the average rate of approximately 13 percent per year. Figure 1 shows that the world production nearly tripled during the period 1945 to 1965, while United States consumption only doubled during the same period. However, during the period 1956 to 1967, domestic apparent consumption fluctuated between 665,000 and 813,000 short tons per year and may be leveling off as substitute materials (such as fiberglass and plastics) provide competition. The relative importance of the various industrial uses of asbestos is given in Table 12 in the Appendix. It is seen that the highest input of asbestos occurs in the asbestos cement, floor tile, asbestos paper products, and asbestos textile industries. The proportions of asbestos used in various products are shown in Tables 13 and 14 in the Appendix. ------- 30 Thousands of Short Tons U.S. WORLD CONS. PROD. 900 3,500 800 3,000 700 2,500 600 2,000 500 1,500 400 1,000 1945 I I I 1955 1960 1965 Comparison of Trends in World Production and U.S. Consumption of Unmanufactured Asbestos’ 70 ” 71 FIGURE 1 1970 U. S. CONSUMPTION WORLD PRODUCTION 1950 ------- 31 of the 78,056 short tons of domestic production in 1965, 66 percent were produced in California and 31 percent* in Vermont, amounting to 97 percent of the total production. This 97 percent was produced and processed in five counties. 17 ° More than 50 percent of the 124 plants comprising the asbestos products industry were located (in 1963) in the States of California, New Jersey, Illinois, Pennsylvania, and Texas, in decreasing order. 41 Bobyleva 24,25 have shown that the air can be polluted by asbestos from plants manufacturing asbestos products. This asbestos may be carried in the air for distances of 25 to 50 miles. In a study of asbestos air pollution from three plants in the U.S.S.R.., they found that at a distance of 3 km from the plant, the dust concentration ranged from 0 to 6,000 ig/m 3 ; at 1.0—1.5 km it was 3,000—33,000 ig/m 3 ; and at 0.5 km it was 6,000 to 34,000 ig/m 3 . In the United States some attempts 206 have been made to determine the concentration of asbestos near asbestos factories, but the asbestos content of the atmosphere was masked by the other dusts. Asbestos fibers were detected, but a quantitative count was not possible. 3.3 Product Sources I The uses of asbestos are numerous. Some products which use asbestos are the following: asbestos cement which may be * trapo1ated . ------- applied as mortar or plaster, or sprayed on walls; insulating materials for the covering of pipes, ducts, boilers, cables, and conduits; siding shingles, roofing shingles, tiles, flat and corrugated sheets, wallboard, clapboard, and automobile undercoating; threads, yarns, wicks, cords, tapes, cloths, sheets, and blankets; friction materials, brake linings, clutch facings, gaskets, and lagging cloths; and asphalt tiles, plastics, and similar materials) 08 Abrasion of brake linings and clutch facings has been suggested as a primary source of asbestos air pollution. 13 145 Ayer and Lynch have examined the emissions from brakes on automobiles and found that the fiber is destroyed by the heat of friction. Asbestos crystalline structures are also destroyed and are recognizable only by the chemical composition. Newhouse and Thompson 175 have reported one case of mesothelioma in a mechanic. The existence of a wide potential for direct or in — direct occupational exposure has been cited 32 ’ 34 ”° 8 ’ 12 ° as a possible explanation for the frequent occurrence of “asbestos bodies” in the general public. Asbestos is now used in more than 3,000 products. Most people working in the construction and demolition of buildings come into contact with asbestos. Electricians and homeowners strip asbestos insulation off wires; the carpenter saws asbestos boards and often pounds the asbestos— insulated furnace ducts to make them fit. As a result, the air around a construction site is contaminated with asbestos fibers, ------- 33 and the foreman, carpenter, painter, plumber, or new occupants all breathe this dust. In most homes, the owner will at some time handle these asbestos products during normal home main— tenarice. A large number of workers in other industries are similarly exposed. Some of these are listed in Table 15 in the Appendix. Although only a few of these people work in the asbestos industry, all may have inhaled sufficient asbestos to show “asbestos bodies t ’ upon autopsy. The hazard is there, but how great is the hazard? It will be necessary to obtain quantita- tive concentration data to delineate its seriousness. From the above discussion it may be concluded that approximately 100,000 asbestos workers in the United States have a high exposure to asbestos. 195 An additional 3.5 million construction workers—carpenters, welders, electricians, masons, plumbers, steamfitters, tile setters, etc.—are indirectly exposed,either by themselves handling asbestos products or by working on the job with people handling asbestos. 195 3.4 Environmental Air Concentrations Only one estimate of the environmental air concentrations of asbestos in the United States was found. Smith and Tabor 206 have roughly estimated that urban air in the vicinity of heavily traveled streets contains 600 to 6,000 particles/rn 3 . They indicate that the validity of these values is highly suspect because the methods available for the determination of asbestos ------- 34 are inadequate at the concentrations found in the urban air. ------- 35 4. ABAT EMENT The asbestos industries in the United States have developed elaborate ventilation systems to prevent high dust 13, 95 concentrations which might be inhaled by the workers. This dusty air is passed from the ventilators through fabric sleeve filters and then discharged to the atmosphere. The asbestos fibers are easily filtered out since the fibers form a mat which becomes an absolute filter. 1 In addition to the ventilation system, it has been necessary to carry out some operations (such as spinning and weaving) as wet processes to eliminate dust. As a result, the pollution from factories is minimal. Attempts to measure concentrations in the vicinity of an asbestos plant have proved futile with present analytical methods. Pollution during the transportation of asbestos has been controlled by enclosing the material in plastic—coated bags. Although the most common procedure used to suppress dust emission is wetting of the material, it is unfortunately not desirable to wet a large number of asbestos products. In New York, insulators are required to enclose the area when asbestos fireproofing is blown onto steel frames, but even this does not prevent pollution. Asbestos fibers are reported to be a common occurrence in the air around construc- tion sites. 34 ------- 36 No information has been found on the abatement methods used in United States asbestos mines and in asbestos mills near the mines. ------- 37 5. ECONOMICS No information has been found in the literature on the damage costs or economic losses due to the effects of asbestos air pollution on humans, animals, plants, or materials. However, a large fraction of the people in the United States have been exposed to asbestos, including the following: (1) approximately 100,000 workers using asbestos in their occupations, (2) approximately 3,500,000 construction workers ex- posed indirectly to asbestos as they work with asbestos products or near those who handle asbestos products, (3) approximately 50,000,000 Americans who possibly have “asbestos bodies” in their lungs. No attempt has been made to assess the cost of health impairment for these people. Workmen’s compensation laws for 234 dust diseases are in effect in most States. No information has been found on the cost of the present and future abatement of air pollution by asbestos in this country. The data in Table 16 in the Appendix, which refer to the asbestos industry in Britain, 95 show that the dust extraction equipment cost alone, for a given size and type of plant, amounts to 27.5 percent of the total capital cost and approximately 7 percent of the operating cost of that plant. The type of control equipment used is primarily designed to meet government speci- fications relating to occupational health standards. Data on the production and consumption of asbestos are presented in Section 3. ------- 38 6. METHODS OF ANALYSIS 1,2,206 Of the methods presently being used to count dust samples in the asbestos industry,* none is applicable to atmospheric asbestos air pollution. There are at present no proven satisfactory methods for the collection, detection, and identification of asbestos fibers in the 0.1 to 5.0 u range in ambient air. Satisfactory sampling can probably be accomplished by use of a membrane filter—pump system. The major difficulty lies in the problem of identifying a very few asbestos fibers in the presence of relatively large num- bers of a wide variety of other inorganic particulate matter found in the same air. Attempts to determine the asbestos content of urban air have revealed the need for development of new methods. Battelle Memorial Institute is currently developing one such method for the National Air Pollution Control Administration. 205 *In all the asbestos monitoring methods used, microscopic counting of the fibrous particles is necessary to determine the proportion of fibrous material, and even then it is not known what fraction of the fibers are asbestos. Counting of fibers by eye under the microscope is tedious and difficult. If the number of fibers is less than 1 percent (<5 wt%) of total dust, the other dust masks the fibers, and quantitative results cannot be obtained. In parts of the asbestos industry where the asbestos—to— dust ratio is high (>5 wt%), it is often possible to determine the asbestos content indirectly. 136 For example, if the pro- portion of asbestos in the airborne dust was known by microscopic count for a given sampling location, the concentration (at least the order of magnitude) could then be inferred from a simple measurement of the concentration of the total dust. ------- 39 Modern analytical methods arid instrumentation used in the asbestos industry are listed below: Microscopic particle counting of samples on membrane filters 1 ’ 2,14,15,57, 97,136,187 Thermal precipitators 1 ’ 2 ’ 97 ’ 136 ’ 187 Impingers ” 2 ’ 4 ’ 15 ’ 136,187 Royco particle counter 1 ’ 2 ’ 136 ’ - 87 Mass concentration methods 1 ’ 14 ” 36 ’’ 87 Microsieving 116 Digestion 116 Column chromatography of organics adsorbed on the surf ace 116 X—ray diffraction 14 ’ 46 ’ 47 ’ 116 Low—temperature ashing 116 Atomic adsorption spectrophotometry 14 ’ 116 Electron microprobe 116 Neutron activation 116 Owens jet counter ” 2 2 ------- 41 REFERENCES 1. 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Graves, Asbestos As an Urban Air Contaminant, Arch. Pathol . 81(5):458 (1966). 216. Thomson, J. C., R. 0. C. Kasthula, and R. R. MacDonald, Asbestos as a Modern Urban Hazard, S. African Med. J . 37:77 (1963). 217. Thomson, M. L., A. M. Peizer, and W. J. Srnither, The Discriminant Value of Pulmonary Function Tests in Asbestosis, Ann. N.Y. Acad. Sci. 132:421 (1965). 218. Threshold Limit Values for 1967. Adopted at the 29th Annual Meeting of the American Conference of Governmental Industrial Hygienists, Chicago, Ill. (May 1-2, 1967). 219. Timbrell, V., The Inhalation of Fibrous Dusts, Ann. N.Y. Acad. Sci. 132:421 (1965). 220. Utidjian, N. D., P. Gross, and R. T. P. deTreville, Ferruginous Bodies in Human Lungs, Arch. Environ. Health 17:327 (1968). 221. Vasil’eva, A. A.., and N. D. Manita, Carboxyhemoglobin in the Blood of Persons Directing City Traffic, Gigiena I Sanit . 25(12):77 (1960), Translated by B. S. Levine, U.S.S.R. 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Monthly Report——Asbestos Production in Canada (Ottawa: Bureau of Statistics, 1968). ------- APPENDIX A ------- APPENDIX A TABLE 5 CANCER OF THE LUNG AMONG ASBESTOS DRKERS 43 No. With No. of Years Lung Comparison Place Population Studied Workers Followed Cancer Groups United Kingdom Reported deaths fzom asbestos 235 1924—1947 31/235 (13.1%) SilicotiCS (1.32%) United Kingdom Cases of asbestosis in 1,247 autopsies with pneumoconiosis 121 17/121 Silicotics (6.9%) United Kingdom Asbestos textile workers, industry areas, 20 years’ or more exposure 113 1922—1953 11/39 deaths 0.8 Expected United Kingdom Reported deaths from asbestosis 365 1924—1955 65/365 (17.8%) Quebec Chrysotile miners and mill workers with over 5 years’ employment 5,958 1950—1955 9/187 deaths 6+ Expected Pennsylvania Workers in asbestos products plant employed in 1938—39, aged 25—64 1,495 1940—1960 19/186 deaths 5.61 Expected New York & Insulating workers, over 632 1932—1962 45/255 6.6 New Jersey 20 years’ union membership deaths Expected (continued) r’) ------- APPENDIX A TABLE 5 CANCER OF THE LUNG AMONG ASBESTOS WORKERS (Continued) Place Population Studied No. of Workers Years Followed No. With Lung Cancer Comparison Groups California Insulating workers, mixed, 15 years in trade, aged 35—64 529 1954—1957 10/41 deaths 2.8 Expected Dresden All asbestos trade mixed exposures 2,636 1924—1963 34/150 deaths 11.4 Expected United States Asbestos textile workers employed in 1948—1951, aged 15—64 2,833 1951—1963 24/285 deaths 11.9 Expected United Kingdom Reported deaths from asbestosis 584 1924—1963 146/584 (25%) Bulgaria Agricultural workers near an asbestos mine 3,325 1962 155/3325 asbestosis New York Asbestos insulators em— ployed more than 15 years, aged 40—80 152 1945—1965 18/46 deaths 3.1 Expected Pennsylvania Asbestos textile and friction workers 68 1957—1962 13/68 deaths ------- APPENDIX A TABLE 6 “ASBESTOS BODIES” IN CONSECUTIVE OR RANLXDM AUTOPSIES Location • Total Cases % Posi- tive % Positive by Age* - Sex % Positive* Year of Study Refer— ence <24 25—34 35—44 45—54 55—64 65—74 >75 Female Male Capetown 500 26.4 .5 (4.3) 2.4 (25.6) 4.4 (28.4) 4.6 (22.4) 7.4 (31.6) 7.4 (28.0) 7.8 (20) 18.6 (30.4) 1960 214,216 Miami 500 27.2 0 0 1 (16.1) 3.4 (23) 5.6 (27.2) 9.2 (30.6) 9 (31.9) 8 (20.4) 19.2 (31.6) 1961 214,216 Pittsburgh 100 41 0 (0) 5 (83) 5 (46) 3 (38) 13 (54) 8 (40) 6 (30) 16 (34) 25 (47) 1964 40 Milan . 100 51 (<—- 3 (14) — >) 30 (60) 18 (66) 16 (44) 35 (54) 1966 67 Tyrieside Jerusalem 311 100 20.3 26 0 (0) < 0.3 (25) 1 (14) 1.6 (19.2) ---- )( - 2.9 (17.3) 4.8 (18.5) 7—> (21) 7.7 (28.9) —18 (30) 2.9 (15) —>) 4.2 (13) 10 (29.1) 16.1 (25.5) 16 (22.2) 1967 1967 11 184 Glasgow 100 23 0 0 0 1 (12) 4 (22) 11 (32) 7 (19) 0 (0) 23 (37) 1967 188 Finland 264 57.6 1.5 (57) 3.0 (57) 3.8 (71) 8.7 (55) 20.0 (64) 16.7 (58.7) 3.8 (34.5) 23.9 (54.3) 33.7 (60) 1966 167 Sweden 34 35.3 0 0 0 0 11.7 (80) 14.7 (25) 18.8 (43) 14.7 (38) 20.6 (33) 1966 82 (continued) ------- APPENDIX A TABLE 6 “ASBESTOS BODIES” IN CONSECUTIVE OR RANDOM AUTOPSIES (Continued) Location Total Cases % Posi— tive Year of Study Refer— ence % Positive by Age* <24 25—34 35—44 45—54 55—64 65—74 >75 Positive Female Male Johannesburg 39.2 1965 234 San Francisco 42 1966 43 Belfast 200 20 . 1965 60 London Montreal 50 100 6 48 <- —3 ---- (30) 48— > <—27—- (50) > 16 (36) 32 (57) 1964 1966 102 7 (50) New York 355 50.5 3.9 (29.8) 46.5 (53.7) 1966 195 *Nurp.bers in parenthesis represent percentage of group—age or sex. 0 ------- APPENDIX A TABLE 7 COMPOSITION AND PROPERTIES OF ASBESTOS MINERALS 66 Approximate Formula Qirysotile Crocidolite Arnosite 1.5 MgO—5.5FeO— 8S1O 2 H 2 O Na 2 0—3FeOFe 2 O— 8SiO 2 H 2 O 3MgO—2SiO 2 2H 2 O Percentage of Malor Components 40.3 51.4 49.3 Silica Si0 2 Alumina A1 2 0 3 0.7 Ferrous Oxide FeO 1.0 20.3 40.9 Ferric Oxide Fe 2 0 3 1.5 17.5 0.4 Mariganous Oxide MnO 0.1 0.7 Calcium Oxide CaO 0.2 0.8 0.4 Magnesium Oxide MgO 42.4 1.4 5.7 Sodium Oxide Na 2 0 6.2 0.2 Potassium Oxide K 2 0 0.3 Carbon Dioxide CO 2 0.2 0.4 0.2 Water of Crystallization H 2 0 13.7 1.9 1.9 (continued) ------- APPENDIX A TABLE 7 COMPOSITION AND PROPERTIES OF ASBESTOS MINERALS (Continued) Approximate Formula Chrvsoti le Crocidolite Na 2 0—3FeOFe 2 O— 8Si0 2 H 2 O Amosite 1.5 MgO—5.5FeO— 8SiO H 2 O 3MgO-2S1O 2 2H 2 O Trace Organic Impurities Oil—wax (mg/100 g fiber) 4—7.6 4—200 4—20 Benzo(a)pyrene . (ug/l00 g fiber) none detected 0.2—24 0.2—2.4 Trace Inorganic Imp ities ( ig/g fiber) Pb 2 5 20 Sn <5 <5 <5 Ga <2 <2 2 Bi <5 <5 <5 V 50 <2 <2 Mo <2 <2 <2 Cu 35 7 7 Ti 50 50 300 Ag <0.2 0.2 0.2 Ni 5,000 (1,000—14,000) <10 (<100) 1,000 (<100) Zv <200 700 1,000 Co <5 (<100) <5 (<100) <5 (<100) Mn 130 (400—500) 180 (200) 7,000 (7,900) Cr 1,000 (400—900) 20 (<100) 150 (<100) (continued) ------- APPENDIX A TABLE 7 COMPOSITION AND PROPERTIES OF ASBESTOS MINERALS (Continued) Approximate Formula Chrysotile Crocidolite Z ’ mosite Radioactive Contaminants • ( ic/g fiber) K 40 0.14 0.02 0.55 Th 238 <0.01 0.05 Ra 226 0.07 0.15 Physical Properties Flexibility Length Texture Tensile strength Acid resistance Heat resistance Spinnability Very flexible Short to 3” Harsh to silky Very high Fairly soluble Good Very good Fair to good Short to 3$I Harsh to soft Very high Very good Poor Fair Good ¼” to 6” Coarse but pliable Fair Good Good Fair C.’ OD ------- APPENDIX A TABLE S WORLD PRODUCTION OF ASBESTOS 17 ° (Short Tons) Location 1962 1963 1964 1965 1966 b,e North AmerIca Canada (sales) . United States (shipments) . • . 1,215,814 1,275,530 • . 53,190 66,396 1,420, 769 101,092 1,387,555 1,479,281 118,275 125,928 South America Argentina . Bolivia (exports) Brazil • . . • 203 • 5€ • 4900 a 365 10 1, 440 542 243 c 7 3 1 , 430 a,c,f 1,204 4 1,820 Europe Austria Bulgaria France Greece Italy Portugal U.S.S.R. Yugoslavia Africa • . • S I • • . . . . . 503 1, 323 10,869 60,860 7,401 638 l, 32 : 3 C 10,201 26 ,O 94 c 74 63, 016 29 755 , 000 a,c 9,074 l, 433 c 11,611 24, 289 75,573 810 , 000 a,c 9,280 l, 433 c 13, 307 71506 c 85 a 79,214 53 c 865,000 10,585 13,250 85 a 90,464 10 925, 000 a 8,411 Botswana Kenya Mozarubique Rhodesia, Southern South Africa . . . Swaziland . . . United Arab Republic • . 2,375 • 5 212 370 • l 42 ,l 95 c • 221,302 • 32,830 • 606 2,368 78 2,161 204 888 880 a 136 73 l42,254’ 153,450 176 , 149 c 1751000 a 205,744 215,592 240,752 276,597 33,350 39,862 40,884 36,142 192 1,739 3,225 2,057 (continued) ------- APPENDIX A TABLE 8 WORLD PRODUCTION OF ASBESTOS (Continued) (Short Tons) Location 1962 1963 1964 1965 1966 b,e Asia China Cyprus . . India . . . Japan . . . . . . . . . • . . • . , • • • . 100,000 22,391 1,865 15,407 110,000 19,962 3 ,O 38 C 18,210 130,000 13,755 3710 C 17,979 140,000 l 7 , 622 c 4,989 16,451° 140,000 24,449 7,646 17,067 Korea, South . . . . 1,333 2,120 1,402 l,710C 687 Philippines . . . . . 1,037 421 586 Taiwan • • . . 525 604 526 883 721 Turkey . • . • • 709 408 1,291 1,376 1,258 Oceania Australia . . . . • 18,416 13,374 13,545 11,647 13,472 New Zealand • . World Totala . . • . • . 457 439 2655 000° 2760000 c 3050000 C 3,140,000° 3,350,000 a Estimated bpreiiminary C Revised. dAsbestos also is produced in Czechoslovakia, Eritrea, Malagasy, North Korea, and Rumania. No estimates for these countries are included in the total because production is believed to be negligible. eCompiled from data available May 1967. Bahia only. g nciuaes asbestos flour. ------- APPENDIX A 71 TABLE 9 THE PRODUCTION AND APPARENT CONSUMPTION OF ASBESTOS IN THE UNITED STATES 41 ” 70 ” 7 ’ —— Qu antities in Short Tons Year Production Imports Exports Consumption 1967 123,190 645,110 47,710 720,580 1966 125,928 726,459 46,996 805,391 1965 118,275 719,559 43,126 794,708 1964 101,092 739,361 27,147 813,306 1963 66,396 667,860 10,044 724,212 1962 53,190 675,953 2,949 726,194 1961 52,814 616,529 3,799 (665,440) 1960 45,223 669,945 5,525 709,193 1959 45,459 713,047 4,461 754,045 1958 43,979 644,331 3,026 685,284 1957 43,653 682,732 2,893 723,492 1956 41,312 689,910 2,950 782,272 1955 50,431 716,480 7,001 759,910 1950 727,002 1945 378,030 1940 270,000 1935 170,000 - Values (X 1,000) Year Production Exports Imports Asbestos Asbestos Products 1967 $11,100 $66,000 $6,030 1966 11,056 73,100 5,763 $21,963 1965 10,162 70,457 5,294 19,139 1964 8,143 72,973 3,199 16,288 1963 5,108 61,739 1,304 16,267 1962 4,677 64,112 598 14,274 1961 4,347 (63,000) 759 1960 4,231 63,345 857 1959 4,391 65,006 793 1958 5,127 58,314 424 13,233 1957 4,918 60,104 350 15,223 1956 4,742 61,939 375 14,181 4,534 59,339 1,497 12,464 ------- APPENDIX A TABLE 10 REGIONAL DISTRIBUTION OF ASBESTOS MINING AND PROCESSING 170 ’ 171 (Ranking and Production) Rank Quantity (Short Tons) Value (X 1,000) f_. 1 1960 1964 1966 1964 1965 1966 1964 1965 1966 V .. ‘ iif. Calif. 55,041 — 74,587 81,671 $4,419 $6,177 $6,945 2 Ariz. Vt. Vt. * * * * * * 3 N.C. Ariz. Ariz. * 3,469 * * 441 * 4 Calif. N.C. N.C. * (55,041) * (78,056) * (81,671) * (4,419) * (6,177) * (6,945) *Data withheld to avoid disclosure of producer’s confidential the Bureau of Mines. information to r\.) ------- APPENDIX A TABLE 11 ASBESTOS MINES IN THE UNITED STATES, 1966170 Chrysoti le Chrysotile Chrysotile Chrysotile Chrysotile Chrysotile Chrysotile Chrysotile 1 2 3 4 1 2 3 Atlas Minerals Corp. Coalinga Asbestos Co. Pacific Asbestos Corp. Union Carbide Corp. b Ash Bonding Co. Vermont Asbestos Mines Div. of Ruberoid Co. Jacquays Mining Corp. Western Asbestos Mfg. Co. Metate Asbestos Corp. Kyle Asbestos Mines of Ariz.a LeTourneau Asbestos Corp.a Fresno County Fresno County Ca laveras County San Benito County Napa Orleans County (Lowell) Salt River Valley (North of Globe) Near Mine Near Mine Near Mine Monterey County (King City) State - Mineral Production Ran]c Name of Producer Location——County or City of Mine Processing Plant California Vermont Arizona 1 North Carolina Crocidolite 1 aRanked by production only within the State. bNot in operation during previous years. Powhatan Mining Co. Yancey County t urnsvi11e) —I ------- 74 APPENDIX A TABLE 12 APPARENT ASBESTOS CONSUMPTION, 1965170 (In Thousands of Short Tons) Use World 97 United States* Asbestos Industry Production Mining and Processing 78 Asbestos in Products Textiles 66 17 Cement 2, 190 548 Friction Materials 111 28 Asbestos Paper 220 55 Floor Tile 307 77 Paints, Roof Coating, Caulks 85 21 Plastics 21 5 Miscellaneous 221 55 Total Products 3, 221 806 *Based on 25% of world consumption. ------- 75 APPENDIX A TABLE 13 PROPORTION OF ASBESTOS IN VARIOUS ASBESTOS PRODUCTS 17 ° Percenta Product Asbestos Asbestos textiles 80—100 Asbestos cement 15—90 Friction materials and gaskets 30—80 Asbestos paper and products 80—90 Floor tile 10—30 Other asbestos products U.D.C aQ rysotile asbestos is used unless otherwise stated. to 90% chrysotile, with some materials containing as much as 85% arnosite and small amounts of crocidolite and antho— phyllite. CThese products contain undetermined quantities of chrysotile, tremolite, actinolite, and anthophyllite. TABLE 14 QUANTITY AND VALUE OF ASBESTOS INPUT BY INDUSTRY 1963170 Quantity Value Short Fraction Fraction Product Tons(000) of Total $jOOQ,000J of Total Asbestos textiles 66 0.02 26.4 0.06 Asbestos cement 2,190 0.68 328.5 0.78 Friction materials and gaskets 111 0.04 11.1 0.03 Paper arid products 220 0.07 19.8 0.05 Floor tile 307 0.09 13.2 0.03 Paint and coating fillers 85 0.02 3.7 0.01 Plastics 21 0.01 9.2 Other 220.7 0.07 19.7 0.04 Total 3,220.7 1.00 423.3 1.00 ------- 76 APPENDIX A TABLE 15 POPULATION GROUPS WITH OCCUPATIONAL AND ENVIRONMENTAL EXPOSURE TO ASBESTOS 108 Occupational Groups Asbestos rock miners, loaders, truckers, crushers, millers, asbestos spinners, weavers, electrical appli- ance and wire manufacturers, masons, carpenters, heating equipment workers, rubber workers, shingle and tile manufacturers, building material manufacturers, filtering material manufac- turers, molders of asbestos products, asbestos—asphalt makers, putty manufacturers, asbestos cement makers, asbestos paper, cardboard and brake—lining producers, asbestos felt insulation workers, asbestos sound insu- lation workers, asbestos insu- lators, pipe coverers, asbes- tos tube wrappers, asbestos cork insulation workers, con- struction workers, automobile makers, garage attendants Nonoccupational Groups Residents in vicinity of asbestos processing and tex- tile mills inhaling plant effluents polluted with asbestos dust, and indivi- duals living and working along roads on which asbestos is trucked; residents in the vicinity of asbestos mines; residents in vicinity of building construction and demolition, inhabitants of homes or offices with asbes- tos acoustical tile ------- 77 APPENDIX A TABLE 16 ASBESTOS CONTROL EQUIPMENT 95 Cost Data Asbestos Textile Industrya Dust extraction equipment Total capital cost (fixed) $1,500,000 Operating cost per year $ 250,000 Operating cost/labor cost 7 % Operating cost/total cost 2.7% conversion Asbestos Minesb Dust extraction equipment Total capital cost (TCC) $ 360,000 (TCC/TcC of plant) x 100 27.5% Operating cost (per year) $ 195,000 Specifications Asbestos Textile Industrya Volume of dust—containing air extracted from textile machines 1,000,000 ft 3 /min or 700 ft 3 /min/operative Quantity of asbestos dust filtered per year (at above rate) 700 tons or 2.8 tons/worlcing day Asbestos Mines Total installed horsepower 796 part used to generate air for dust removal 230 (29%) Total air needed (for aspiration and dust removal) per pound of 3 fiber produced 1,350 ft aFigures apply to the Turner Bros. Asbestos Co. plant at Rochdale, England. bFigures apply to the Cape Asbestos Co. at Penge in the Transvaal. The most modern mill (in Canada), which is 10 times larger, needs only about half the quantity of air stated (using gravity instead of air—swept mills and horizontal transportation of ore). ------- APPENDIX A TABLE 17 ANALYSIS OF ASBESTOS AND ASBESTOS PRODUCTS EXPORTS AND II 4PORTS 17 ° . Exports Re—exports Short Tons Dollars(000) Short Tons Dollars (000J 1965 1966 1965 1966 1965 1966 1965 1966 Total 42,995 46,690 5,271 5,712 131 306 23 51 Other products * * 4,389 5,058 * 8 11 Total 19,087 21,907 52 56 Imports — Short Tons Dollars (000L 1965 1966 1965 1966 Crude and spinning fibers 1,251 1,455 326 325 50 176 10 30 Nonspinning fibers 24,221 28,017 3,622 3,973 81 130 13 21 Waste and refuse 17,523 17,218 1,323 1,414 Gaskets and packing 1,732 2,678 4,528 5,261 1 1 Brake lining 3,065 3,630 4,728 5,236 1 1 2 2 Clutcl’i lining (number) 2,020,864 2,246,986 1,691 1,897 5,000 5,000 4 1 Textiles and yarn 794 900 1,067 1,326 Shingles and clapboard 5,465 10,010 1,096 1,797 113 231 37 41 Asbestos—cement 6,101 4,742 1,588 1,332 Sub total 14,698 16,849 5,114 5,232 44 45 * Chrysolite Crude Spinning/ Textiles All Other Total Crocidolite Amo site Total 12,496 17,339 643,149 672,984 21,165 17,042 711,191 6,596 16,839 642,894 666,329 26,995 23,934 716, 258 6,245 55,077 70, 454 6,319 56,308 73,100 *Not available. ------- 79 APPENDIX A TABLE 18 SELECTED STATISTICS FOR THE ASBESTOS MANUFACTURING INDUSTRY 41 (Employment Size) Number of Value of Number of Number of Number of Production Shipments Employees* Companies Plants Workers $ (000) 1—49 39 39 308 8,264 50—99 6 6 231 4,827 100—2,499 10 17 2,445 89,131 over 2,500 18 62 12,754 407,014 Total 73 124 15,738 509,236 *The employment size class is determined by the total company employment in all manufacturing activities in the U.S., including central offices and auxiliaries serving manufacturing establishments. All establishments of a company are therefore included in the same employments size column regardless of establishment size. ------- 80 APPENDIX A TABLE 19 SELECTED STATISTICS FOR THE ASBESTOS PRODUCTS INLXJSTRY 41 Expenditures (in $000) 1958 1963 New plant and equipment New structures 2,419 2,613 New machinery and equipment 10,418 9,768 Total 12,837 12,381 Used plant and equipment 428 1,289 Total 13,265 13,670 ------- APPENDIX A 81 TABLE 20 ASBESTOS USES 85 Textiles : Varieties used: Chrysotile, crocidolite, and in part amo site Yarns and Cords : Processes: Weaving of yarns and cords Braiding (interlacing) Classification of chrysotile fabrics: Class Quality Code Asbestos content (% ) 1 AAAA 75—79.9 2 AAA 80-84.9 3 AA 85—89.9 4 A 90—94.9 5 Underwriters 95—100 Commercial Seating and Packing Materials : Packing (woven fabrics) stuffing for boxes and sleeves manhole rings, boiler covers Flat Packing : Gaskets, flanges (on pipes) and containers 1. Without metal: high pressure gasket sheets (rubber) 2. With metal: material for sealing cylinder heads and exhausts in motors and combustion engines, and for sealing compressors and turbines Asbestos Boards and Papers: Boards Filtering and clarifying Coverings, coatings, casings, and jacketings for all kinds of surfaces Manufacturing of welders’ and melters’ shields Slideways in the glass industry Handles and fire—doors Auto Parts Safes Protective walls Curtains, etc. (continued) ------- 82 APPENDIX A TABLE 20 (Continued) ASBESTOS USES 85 Sheets Inner/outer linings of furnaces and heating vessels, drying ovens, incubators, heaters, climate— controlled spaces, etc. Plates Insulating buildings against vibrations (aluminum— asbestos) Solar—heat reflecting surfaces (70% of solar heat) Special Asbestos Papers Filters Asbestos Cement (10 to 25% asbestos): Slabs Corrugated sheets Pipes Corrugated tiles for roofs in industry, agriculture, and dwellings Planks for platforms in buildings under construction Balcony canopies Rain gutters Interior walls Ventilating shafts Air conditioning assemblies Pressure piping (for underground drinking water distribution systems, fuel gas, and sewage) Cooling towers (electricity—generating stations) Thermal Insulants and Fire—Proofing : Sprayed asbestos ( insulant in both heating and refrigeration), sound absorbent (eliminates booming and improves acoustical properties of walls and ceilings) Magnesia asbestos (85% magnesia, 15% asbestos) as thermal insulant for covering pipes Friction Material : Woven: Brake lining Noriwoven: Clutch lining Transmission lining (continued) ------- APPENDIX A 83 TABLE 20 (Continued) ASBESTOS USES 85 Asbestos Plastics : Flooring tiles (asbestos—asphalt tiles and, increasingly, asbestos—polymers of vinyl) Pressed or molded (thermal insulation and in electrical machinery) Resinated asbestos felt (manufacturing of wings and firing of missiles and expansion cones for nozzles of boost motors). Other uses in aircraft industry: nozzles for motor tubes, missile tailpipes, and missile—heat barriers; fuselages for guided missiles, fuel tanks for fighter bombers, cabin floors, etc. Radar (large molded reflectors and scanners) Asbestos Acid-Resistant Compositions : Used mostly in chemical industry ------- 84 APPENDIX A TABLE 21 1967 LIST OF MA 1JFACTURED ASBESTOS PRODUCTS 85 Industry and Product Description Quantity Measure Miscellaneous Nonmetallic Mineral Products Asbestos Products Asbestos Friction Materials Brake Linings Woven, containing asbestos yarn, tape, or cloth Linear feet Molded, including all nonwoven types Cubic feet Clutch facing Woven, containing asbestos yarn, tape, or cloth Thousand pieces Molded, including all nonwoven types Thousand pieces Asbestos—Cement Shingles and Clapboard Siding shingles and clapboard, including accessories Squares Roofing shingles Squares Asphalt Floor Tile Thousand square Asphalt floor tile yards Vinyl Asbestos Floor Tile Thousand square Vinyl asbestos floor tile yards Asbestos Textiles and Other Asbestos— Cement Products Asbestos textiles Yarn, cord, and thread Pounds Cloth Pounds Other asbestos textiles, including roving, lap, wick, rope, tape, carded fibers, etc. Pounds Asbestos—cement products Flat sheets and wallboard, all thicknesses converted to ¼” basis 100 square feet Corrugated sheets 100 square feet Pipe, conduits, and ducts, including pressure pipe Short tons (continued) ------- 85 APPENDIX A TABLE 21 (Continued) 1967 LIST OF I’4ANUFACTURED ASBESTOS PROIXJCTS 85 Industry and Product Description Quantity Measure Asbestos felts Roofing—asphalt or tar saturated Short Tons Other Short Tons Other asbestos and asbestos—cement products, including rnillboard and prefabricated housing components Gaskets and Insulation Gaskets, All Types Gaskets (for sealing nonmoving parts) Asbestos, asbestos—metallic, and asbestos—rubber Packing (except leather, rubber, and metal) and Asbestos Insulations Asbestos compressed sheet Pounds Packing (for sealing moving parts) Asbestos, asbestos—metallic, and asbestos—rubber Thousand pounds Insulation materials containing asbestos pipe insulation Cellular and laminated Linear feet 85 percent magnesia Linear feet Diatomaceous silica, calcium, silicate, expanded silica, and asbestos fiber Linear feet Other pipe insulation Linear feet Block insulation, including sheet and lagging Thousand 85 percent magnesia board feet Diatomaceous silica, calcium silicate, expanded silica, and Thousand asbestos fiber board feet Other block insulation, including Thousand celluar and laminated board feet All other asbestos insulation ------- APPENDIX A 86 TABLE 22 ASBESTOS PROtUCT MANUFACTURING PLANTS, 196341 4 ocation Total Plants No. of_Plants with Emplo ment of 1— 19 20— 49 50— 99 100— 249 250— 499 500— 999 1, or 000 more Jew Hampshire Belknap 1 1 Hilisborough 1 Total 2 1 1 as sachusetts Essex 1 1 Franklin 1 1 Middlesex 2 1 Suffolk 2 2 Worcester 1 1 Total 7 4 3 onnecticut Fairfield 3 1 1 Hartford 1 1 Middlesex 1 1 Total 5 1 1 1 1 lew York Albany 1 Kings 3 1 1 1 Orange 1 1 Suffolk 1 1 Total 6 2 1 2 ew Jersey Bergen 1 1 Essex 3 2 1 Hudson 1 1 Mercer 2 2 Morris 1 1 Passaic 3 2 1 Somerset 4 2 1 Union 2 1 Total 16 5 2 3 5 (continued) ------- APPENDIX A 87 TABLE 22 (Continued) ASBESTOS PRODUCT MANUFACTURING PLANTS, 196341 • Location Total Plants No. of Plants with_Employment of 1— 19 20— 49 50— 99 100— 249 250— 499 500— 999 1,000 or more Pennsylvania Elk 1 1 Lancaster 1 Montgomery 2 2 Northampton 1 1 Philadelphia Cit 3 2 1 Potter 1 1 Total 9 3 1 3 1 Ohio Cuyahoga 1 1 Paulding 1 i Portage 1 1 Ross 1 1 Total 4 1 3 Indiana Henry 1 1 Huntington 1 1 Kosciusko 1 1 Lagrange 1 1 Lake 1 1 Rush 1 1 Total 6 1 1 2 2 Illinois Cook 8 5 1 2 Kankakee 1 1 Lake 4 2 1 Will 1 1 Total 14 5 1 3 4 Michigan Wayne 1 1 Total 1 1 (continued) ------- APPENDIX A 88 TABLE 22 (Continued) ASBESTOS PRODUCT MANUFACTURING PLANTS, 196341 ocation Total Plants No. of Plants with_Employment of 1— 19 20— 49 50— 99 100— 249 250— 499 500— 999 1, or 000 more rj 5 fl jfl Milwaukee Total issouri St. Louis St. Louis City Total (an s as Barton Total Tirginia Essex Frederick Norfolk City Total forth Carolina Mecklenburg Union Total ;outh Carolina charleston Marlboro Total 4eorgia DeKaib Talbot Troup Total 2 2 2 2 1 1 1 1 1 1 1 1 2 I 1 2 3 5 1 1 1 1 1 3 2 1 3 1 1 2 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 3 1 1 2 (continued) ------- TABLE 22 (Continued) ASBESTOS PRODUCT MANUFACTURING PLANTS, 196341 Location Total — Plants No of Plants with_Employment of 1— 19 20— 49 50— 99 100— 249 250— 499 500— 999 1,0D0 or more Florida Dade 1 1 Total 1 1 Alabama Mobile 1 1 Total 1 1 4ississippi Hinds 1 1 Union 1 1 Total 2 1 1 Louisiana Jefferson 3 2 Orleans 3 1 1 Total 6 1 3 2 rexas Dallas 2 2 Ector 1 1 Grayson 1 1 Harris 3 2 Hill 1 1 Total S 3 4 alifornia Alameda 2 1 1 Contra Costa 1 1 Los Angeles 9 1 2 1 4 Orange 1 1 Sacramento 1 1 San Benito 1 1 San Joaquin 1 1 San Mateo 1 1 Santa Clara 1 1 Total 18 5 3 3 6 ThTITED STATES TOTAL 124 40 10 13 34 21 4 2 APPENDIX A 89 ------- APPENDIX B ------- 92 RESPIRABLE ASBESTOS FIBERS A number of questions arise regarding respirable asbestos fibers. What length of fiber is respirable? What is the particle—to—mass ratio? Should all fibers, whatever their length or diameter, be counted? If not, can any instrument be designed to select the right size distribution in the atmosphere? Timbrell 219 has studied the deposition of fibrous material in the respiratory system. Fibers 50 or even 200 ii. long are found in the lungs because the free—falling speed depends largely on the diameter. Thus, particles less than 3.5 (most asbestos particles are less than 0.5 p) in diameter can possibly penetrate deeply into the lung. The more symmetrical a fiber is, the greater its chance of pene’- trating. The largest compact particles normally found in the lung are about 10 I in diameter. Limitation on the lengths of the fibers which reach pulmonary air spaces is imposed by the nasal hairs and the small diameters of the respiratory bronchioles. These limitations are summarized in Table 23. Respirable fibers have been defined by the British Occupational Hygiene Society 205 as fibers less than 200 .i long, less than 35 in diameter, and having a length—to— breadth ratio of 3:1. Only the fibers longer than 5 i in length are counted. ------- TABLE 23 PENETRATION OF FIBERS THROUGH NASAL HAIRS 219 ength of Fiber (microns) % Penetration through Nasal Hairs 1st Stage 2nd Stage 3rd Sta 0.5 100 100 100 50 75 57 42 100 53 24 11 150 31 10 3 200 26 5 1 250 20 3 300 17 2 350 14 1 Walter 23 ° has investigated the mass of average particles in the asbestos textile industry (see Table 24). He found that respirable dust contains approximately 50 percent asbestos and that 10 particles of dust per ug contain 5 x 10 particles of asbestos per pig. From this conversion factor the threshold limit value for asbestos can be calculated.* as approximately 350 g/m 3 (5 mppcf). TABLE 24 PARTICLE-MASS RELATIONSHIP OF ASBESTOS AS A FUNCTION OF FIBER LENGTH 229 Total Concentration g/m 3 Particles*/cm 3 (approx) Incineration Residue g/m - (approx) Fiber Length in Microns (approx) 100 200 400 600 100 400 1,000 2,500 50—60 200—300 700—800 1,800—2,000 < 150 < 500 < 700 <10,000 *partjcles counted with a Iconimeter. *5 mppcfl77 x io 6 p/m 3 350 ig/m 3 . The con entration estimated in air is 600—6,000 p/m 3 =l.2 — 12 x 10 g/m 3 . 93 ------- 94 Finally, there remains the problem of counting respirable fibers in ambient air. It appears that a fairly sophisticated instrument will be required which can (1) separate the other particles from fibers, (2) identify the asbestos fibers in a host of other fibers, and (3) count only those fibers longer than 5 i and shorter than 200 i with diameters less than 3.5 U. ------- |