------- AIR POLLUTION ASPECTS OF ASBESTOS Prepared for the National Air Pollution Control Administration Consumer Protection & Environmental Health Service Department of Health, Education, and Welfare (Contract No. PH-22-68-25) Compiled by Ralph J. Sullivan and Yanis C. Athanassiadis Litton Systems, Inc. Environmental Systems Division 7300 Pearl Street Bethesda, Maryland 20014 September 1969 ------- FOREWORD As the concern for air quality grows, so does the con- cern over the less ubiquitous but potentially harmful contami- 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) Ethylene Aldehydes (includes acrolein Hydrochloric Acid and formaldehyde) Hydrogen Sulfide Ammonia Iron and Its Compounds Arsenic and Its Compounds Manganese and Its Compounds Asbestos Mercury and its Compounds Barium and Its Compounds Nickel and Its Compounds Beryllium and Its Compounds Odorous Compounds Biological Aerosols Organic Carcinogens (microorganisms) Pesticides Boron and Its Compounds Phosphorus and Its Compounds Cadmium and Its Compounds Radioactive Substances Chlorine Gas Selenium and Its Compounds Chromium and Its Compounds Vanadium and Its Compounds (includes chromic acid) 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 ------- 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 f 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. i 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 Finkelstein, Ph.D. Douglas A. Olsen, Ph0D. James L. Haynes ------- 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 outside 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. ------- 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- i 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 ------- 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. ------- 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 Mesothelioma 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 Experimental Animals 21 2.3 Effects on P-lants 24 2.4 Effects on Materials 24 2.5 Environmental Air Standards 24 3. SOURCES 26 3.1 Natural Occurrence 26 3.1.1 Mines 26 3.2 Production Sources 29 3.3 Product Sources 31 3.4 Environmental Air Concentrations . 33 4. ABATEMENT 35 5. ECONOMICS 37 6. METHODS OF ANALYSIS . 38 7- SUMMARY AND CONCLUSIONS . 40 REFERENCES 43 APPENDIX A 63 APPENDIX B 92 ------- LIST OF FIGURES 1. Comparison of Trends in World Production and U.S. Consumption of Unmanufactured Asbestos 30 ------- 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 Tumors 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 ..... 63 6. "Asbestos Bodies" in Consecutive o» Random Autopsies ..................... 65 7. Composition and Properties of Asbestos ...... 67 8. World Production of Asbestos ........... 70 9. The Production and Apparent Consumption of Asbestos in the United States .......... ..... 72 10. Regional Distribution of Asbestos Mining and Processing .................... 73 11. Asbestos Mines in the United States, 1966 ..... 74 12. Apparent Asbestos Consumption, 1965 ........ 75 13. Proportion of Asbestos in Various Asbestos Products 76 14. Quantity and Value of Asbestos Input by Industry, 1963 ....................... 76 15. Population Groups with Occupational and Environmental Exposure to Asbestos ............... 77 16. Asbestos Control Equipment ......... ... 78 17. Analysis of Asbestos and Asbestos Products Exports and Imports .................... 79 18. Selected Statistics for the Asbestos Manufacturing Industry ..................... 8° ------- LIST OP TABLES (Continued) 19. Selected Statistics for the Asbestos Products In- dustry 81 20. Asbestos Uses 82 21. 1967 List of Manufactured Asbestos Products ... 85 22. Asbestos Product Manufacturing Plants, 1963 ... 87 23. Penetration of Fibers Through Nasal Hairs .... 93 24. Particle-Mass Relationship of Asbestos as a Function of Fiber Length 93 ------- 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. More recently, certain rare cancers, pleural mesotheliomas and peritoneal mesotheliomas, have been associated with inhalation of asbestos fibers by asbestos 1 -j /• g2 workers. Heimann 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 81 found as early as 1927 when Haddow reported finding so- called "asbestos bodies" in the lungs of a person living near ------- an asbestos factory. Since then, several investiga- tors121'175'186'202'226 have reported finding neighborhood cases. The subject of nonoccupational environmental exposure to asbestos assumed a new dimension beginning with the re- — ^ i £ ports of Thomson and his colleagues. 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 40 43 to one-half of the population in Pittsburgh, * San Francisco, Milan, Glasgow, New York, Montreal, Jerusalem, 167 R5 Finland, and Sweden have "asbestos bodies14 in their lungs. These findings indicate that either these asbestos particles or other particles that resemble asbestos in many ways, 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. ------- 2. EFFECTS 2.1 Effects on Humans Asbestosis (a diffuse pulmonary fibrosis), pleural calcification, pleural plaques, lung cancer, and 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 M- 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). ------- 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. The British Occupational Hygiene Society 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 i years later. Once established, asbestosis progresses even after the exposure to dust ceasess illness or death can occur long after exposure to concentrations not producing immediate effects. 3/ The prolonged latency period between exposure and the first signs of asbestosis makes it difficult to establish dose- 43 time relationships. Cooper suggested that a time-weighted ------- average concentration of asbestos fibers of 5 mppcf* is too 234 high. He cites Wells' 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 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 26 Bohme, 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 years1 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. ------- English asbestos workers with over 20 years of employment was 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 et al. 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 Pleura! Calcification and Plaques 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- fication can be readily identified by X-ray. 120 Kiviluoto 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 121 asbestos exposure. This investigator 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 ------- 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. Raunio186 continued the study and found 1,516 adult cases of pleural calcification from 633,201 X-rays taken in 13 Finnish towns and 106 rural communes. 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, Meurman167 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^05 an(j Bulgaria238 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 e_t a.1,. 24,25 concluded that they were suffering from impaired health caused by air pollution from asbestos plants. 2.1.3 Cane er 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 149 quarter of this century. In 1935, Lynch and Smith in the United States described lung cancer found during autopsy of a patient with asbestosis. According to Homburger's data, 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. 147 Lynch and Cannon in 1949 found lung cancer in only three cases (7.5 percent) of 40 patients with asbestosis. Gloyne 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 OQ Bohlig, Jacob, and Kalliabis. 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 19 review, Behrens 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. reported that of 603 persons with asbestosis, lung cancer was found in 83 (13.8 percent) at autopsy. Hueper and Doll 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. 33 Braun and Truan found lung cancer in 12 (three cases were not conclusive) of 187 workers in the Canadian asbestos 96 industry who had died. Boehme 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 114 the beginning of work to death was 28 years. Keal 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 has suggested that the probability of cancer induction is proportional to the number of asbestos fibers/ number of susceptible cells, the concen- tration of carcinogens on the fibers/ and the time from expo sure. Why asbestos is carcinogenic is not clearly understood. At least three hypotheses have been advanced5 (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 DP then produce the cancer. Harington and Roe have shown that (a) chrysotile contains little or no benzo(a)pyrene, but about 100 |ag of chromium per g of fiber and 5,000 |ag of nickel per g of fiber; (b) crocidolite contains 0.2 to 24 jag 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 Hg of benzo(a)pyrene per 100 g of fiber, 100 |-ig of nickel per g of fiber and 15 ug 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. 83 In addition, Hammond 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 199 asbestos workers, he and his colleagues 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 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 mesothelioma. 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 OOfi 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 in 1955, Bonser 30 et al. described a series of 72 autopsies on patients with asbestosis in. which four cases of peritoneal mesothelioma were 152 found. Subsequently, Mancuso and Coulter found five peritoneal mesotheliomas in 1,495 asbestos workers, and 102 Hourihane, 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 103 a subsequent study Hourihane found 74 cases of mesothelioma in a London hospital over a 10-year period. 31 Borow et al. 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 commercial use. In an attempt to determine whether mesothelioma of the serosal surfaces was related in any way to asbestos exposure 198 in the United States, Selikoff et al. 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) 176 were studied by Newhouse and Thompson 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. 198 Selikoff reviewed, 31,652 deaths among the general popula- tion of over 1,048,183 in the United States and found only 195 three cases of mesothelioma. Moreover, he 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 132 of death among asbestos workers. Kogan et al. in 1966 reported 14 cases (31.1 percent), 11 women and 3 men. Pour of the women died of uterine cancer, two of intestinal cancer, two of breast cancer, and 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 Svnergism 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. 1 QQ Selikoff et al.. " 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 OP ASBESTOS INSULATION WORKERS IN NEW YORK, 1963-67199 (By smoking Habits) Smokina Habits No. of Cases3 Observed Deaths Expected Deaths Never smoked regularly 48 0 0.05 History of pipe, cigar- smoking only 39 0 0.13 History of regular . cigarette smoking 283 24 2.98 Total 370 24 3.16 aAll with more than 20 years from onset of exposure 1 cigars Includes cigarette smokers who also smoked pipes or The blue asbestos, crocidolite, from South Africa is believed by many53'79'136'140'209 to be much more carcinogenic 167 than the other minerals of asbestos. Studies in Finland 226 indicate that anthophyllite also produces cancer. Wagner, ------- 17 Smith et al., and recently Godwin and Jagatic, reported that they had induced mesothelioma in mice using chrysotile. ..Moreover, animal experiments76'78'98-100'113'172'225'228 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 87 8Q 1 'iQ crocidolite contains the most benzo(a)pyrene. °?,±->? A11 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 body1' 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 M. in diameter and ------- 18 20 to 100 |Ji 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 naked fiber. There is no doubt that the "asbestos bodies" formed in the lungs of the asbestos workers contain asbestos. Stumphius 210 and Meyer 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 7Q 1 Q4 they contain any asbestos at all. /y'J-yi* This subject xs CO "7Q 7QO currently being debated by several investigators.30''y'*^y 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, 915 and silicon carbide fibers. However, Thomson claims that a skilled pathologist can tell the difference. This contro- co 194 versy should soon be resolved, since both Gross and Selikoff 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 214 scanty, although in some instances the bodies were numerous. 214 In most of the investigations, the method of Thomson 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. In one recent study in 220 Pittsburgh, Utidjian et al.. 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- 40 able 41 percent reported by Cauna (see Table 6 in the Appendix) for residents of Pittsburgh. TABLE 2 DISTRIBUTION OF "ASBESTOS (FERRUGINOUS) BODIES1' IN LUNGS IN PITTSBURGH220 Sex Men - Total Women Total No. of Cases 1 21 15 19 56 2 29 8 5 44 Mean Aqe 89 62 64 70 65 29 57 68 64 60 Fibers/Unit of Lunq 0 1 2-5 >5 0 1 2-5 >5 Distribution (Percent) 2 37 27 34 100 5 66 18 11 100 2.2 Effects on Animals 2.2.1 Commercial and Domestic Animals 121 Kiviluoto 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. ------- 21 182 Peacock and Peacock 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." 234 Wagner described experiments with rats in which 600 animals were exposed to various minerals of asbestos. The results are given in Table 3. 7fi Gross and De Treville made the following observations in studies on rats, hamsters, and guinea pigs. In rats that have inhaled high concentrations (86,000 i-ig/m3) 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 INDUCED BY INTRAPLEURAL INOCULATION OP S.P.F. RATS WITH ASBESTOS234 Asbestos Minerals Croc . Ia Croc. IIb Amosite Chrysotile Silica Saline Total Animals Exposed 100 100 100 100 100 100 600 Animals Died 19 10 4 25 11 5 74 Misc. Nonmaliq. 5 4 1 5 1 2 18 Misc. Tumors 1 1 1 3 Reticulum— cell Sarcomas 1 1 2 2 2 8 Mesothelioraas 12 6 2 18 7 45 Crocidolite from Northwest Cape, South Africa, Crocidolite with oil extracted from it. to to ------- 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 ug/m3. 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 76 2.1. Gross and De Treville also observed a decrease in fiber content -as the time from end of exposure increased. 98 Holt et al. suggest from their observations on rats that fibrotic lesions in the lungs are caused by asbestos fibers (chrysotile) which are less than 3 M. 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 et al. 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 than 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.^^ 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 1 ~ _tfmiimilllll^^^^^ 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 218 Hygienists 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 8-hour day, 40- hour week. This value was recommended by Dreessen et al. 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 Q O (10 particle-years per m ). For example, maximum doses of 6 Q 0.056 mppcf-years (2 x 10 particle-years/m) for 50 years, fi o 0.112 mppcf-years (4 x 10 particle-years/m ) for 25 years, or 0.28 mppcf-years (10 particle-years/m^) 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/m3) Negligible 0-0.4 Low .5-1.9 Medium 2.0-10 High Over 10.0 Only fibers longer than 5.0 |a in length with a 3:1 length-to-breadth ratio are counted. With these standards the risk of asbestosis may be reduced to 1 percent; that is, 1 percent of the workers exposed to a dose of 10 particle-years/m 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) Amphiboles—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 93 the United States. Table 8 in the Appendix lists the world production. Prom 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 120 observed to suffer from asbestosis. i 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 the 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. Pour ------- 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. Amphibole asbestos was mined by Powhatan Mining Co. near Burnsville, Yancey County, N.C. Their output increased 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 A * X was used for roads-tone. 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, 133 and Raunio. They found asbestos dust at distances up to 50 km from the mines, including dust-fall rates ranging from •? 2 1.52 g/100 nr/month at 4 km to 34.6 g/100 m /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. 234 Schepers 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 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 Northwest Cape Province Transvaal Dust Count, mppcf (mppnr*) Mines 2.8-24 (100-840) 2.3-6.5 (80-228) Mill 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. 900 800 700 600 500 400 3,500 3,000 2,500 2,000 1,500 1,000 U.S. CONSUMPTION 1945 1950 1955 WORLD PRODUCTION 1960 1965 1970 FIGURE 1 Comparison of Trends in World Production and U.S. Consumption of Unmanufactured Asbestos ' ------- 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. 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.^ ' ?4 75 Bobyleva et. al.."6*' 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 Hg/m3. at 1.0-1.5 km it was 3,000-33,000 ug/m3; and at 0.5 km it was 6,000 to 34,000 |ag/ms. ?06 In the United States some attempts 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 The uses of asbestos are numerous. Some products which use asbestos are the following: asbestos cement which may be *Extrapolated. ------- 32 applied as mortar or plaster, or sprayed on walls; insulating materials for the covering of pipes, dacts, 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, 108 plastics, and similar materials. 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 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 2''' 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- tenance. 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" 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 195 have a high exposure to asbestos. 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 195 working on the job with people handling asbestos. 3.4 Environmental Air Concentrations Only one estimate of the environmental air concentrations of asbestos in the United States was found. Smith and Tabor206 have roughly estimated that urban air in the vicinity of heavily 3 traveled streets contains 600 to 6,000 particles/m . 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. ABATEMENT 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. 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 fireproof ing 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- 34 tion sites. ------- 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 95 industry in Britain, show that the dust extraction equipment 1 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 |a 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 205 Control Administration. *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 and instrumentation used in the asbestos industry are listed below: Microscopic particle counting of samples on membrane filters1'2'14'15'57'97'136'187 Thermal precipitators1'2,97,136,187 impingers1'2'14'15'136'187 Royco particle counter1'2'136'187 Mass concentration methods1'14'136'187 Microsieving116 1 1 Ft Digestion-1--1-0 Column chromatography of organics adsorbed on the surface116 X-ray diffraction14'46'47'116 Low-temperature ashing116 Atomic adsorption spectrophotometry14'116 11 f\ Electron microprobe^ ° Neutron activation116 Owens jet counter1'2 Konimeter1'2 ------- 40 7. SUMMARY AND CONCLUSIONS Asbestos is an air pollutant which carries with it the potential for a national or worldwide epidemic of lung cancer or mesothelioma of the pleura or peritoneum. Asbestos bodies have been observed in random autopsies of one-fourth to one- half of the population of Pittsburgh, Miami, and San Francisco and will probably be found in the people of every large city. Although asbestos has been shown to produce asbestosis, lung cancer, and mesothelioma in asbestos workers, the relationship between "asbestos bodies" and cancer or asbestosis has not been determined. The latent period required to develop asbestosis, lung cancer, or mesothelioma is 20 to 40 years, and the exposure required to cause asbestosis has been estimated to be 50 to 60 mppcf-years. No such exposure relationship has been es- tablished between asbestos and lung cancer or mesothelioma. Asbestosis, lung cancer.- and mesothelioma are all diseases which, once established, progress even after exposure to dust ceases. Experiments with animals have shown that animals may develop asbestosis or cancer after inhaling asbestos. No information has been found on the effects of asbestos air pollution on either plants or materials. The likely sources of air pollution appear to be the vast number of asbestos products used in our modern society, particularly in the building industry. Mines, factories, and ------- 41 shipping yards may also constitute pollution sources. The world production of asbestos has approximately doubled over the past 10 to 12 years, whereas the domestic consumption has apparently remained relatively constant. These results indicate that while the asbestos air pollution problem of the world may be increasing, the air pollution potential in the United States has remained relatively un- changed. The increase in the number of lung cancer or mesotheli- oma cases reported in the current literature may be due to increases in asbestos use that occurred 20 to 40 years ago. Moreover, the effects of the asbestos being inhaled today may not be reflected in the general health of the population until the 1990's or the next century. The number of people exposed to asbestos has been esti- mated to be 100,000 asbestos workers, 3.5 million people working in areas where asbestos is handled in ways which emit small quantities of dust, and 50 to 100 million people who have breathed or will breathe enough fibers to show positive "asbestos bodies" at autopsy. No measurements have been made of the concentration of asbestos in urban air. A single estimate of 600 to 6,000 particles per cubic meter has been reported. Bag filters are used to control asbestos in the exhaust gases from asbestos factories. Wetting the asbestos or its products has also been used to keep the dust from becoming airborne. The cost of abatement equipment in a British factory ------- 42 amounted to 27.5 percent of the total factory cost and approximately 7 percent of the operating cost. Similar data on the costs of abatement or economic losses due to asbestos air pollution in the United States were not found. No satisfactory method is available to determine the asbestos content at the concentration found in the ambient air. One method is presently under development. Based on the material presented in this report, further studies are suggested in the following areas: (1) Identification of the fibers in the lungs of deceased members of the general public should be completed. (Two studies are in progress.) (2) The relationship between these "asbestos bodies'1 and lung cancer or mesothelioma should be determined. (3) The time-concentration relationship between inhala- tion of asbestos fibers and lung cancer and mesothelioma should be determined. 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Hubert, Tests for Carcinogenicity of Asbestos, Ann. N.Y. Acad. Sci. 132:456 (1965). 208. Smither, W. J., Secular Changes in Asbestosis in an Asbestos Factory, Ann. N.Y. Acad. Sci. 132:166 (1965). 209. Smither, W. J., Asbestos Bodies, Brit. Med. J. 2:51 (1968). 210. Stumphius, J., and P. B. Meyer, Asbestos Bodies and Mesothelioma, Ann. OCCUP. Hyg. ll.:283 (1968). 211. Szymczykievd.cz, K., The Mesenteric Test as a Method of Evaluation of Harmful Effects of Industrial Dust, Med. Pracy (Lodz, Poland) JL5J4): 221 (1964). 212. Tanaka, S., and J. Lieben, Community Chest X-rays for Pneumoconiosis Prevention, Arch. Environ. Health 12; 10 (1966). 213. Thomson, J. G., Exposure to Asbestos Dust and Diffuse Pleural Mesotheliomas, Brit. Med. J. 1:123 (1963). 214. Thomson, J. G., Asbestos and the Urban Dweller, Ann. N.Y. Acad. Sci. 132:196 (1965). ------- 59 215. Thomson, J. G., and W. M. Graves, Asbestos As an Urban Air Contaminant, Arch. Pathol. 81(5);458 (1966). 216. Thomson, J. C., R. o. C. Kasthula, and R. R. MacDonald, Asbestos as a Modern Urban Hazard, S. African Med. J. 31:77 (1963). 217. Thomson, M. L., A. M. Pelzer, and W. J. Smither, 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, 111. (May 1-2, 1967). 219. Timbrell, V., The Inhalation of Fibrous Dusts, Ann. N.Y. Acad. Sci. 132;421 (1965). 220. Utidjian, M. D., P. Gross, and R. T. P. deTreville, Ferruginous Bodies in Human Lungs, Arch. Environ. Health 11:327 (1968). 221. Vasil'eva, A. A., and M. 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. Literature on Air Pollution and Related Occupational Diseases 7:290 (1962). 222. Vigliani, E. C., G. Mottura, and P. 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Monthly Report—Asbestos Production in Canada (Ottawa: Bureau of Statistics, 1968). ------- APPENDIX A ------- APPENDIX TABLE 5 CANCER OP THE LUNG AMONG ASBESTOS WORKERS 43 Place United Kingdom United Kingdom United Kingdom United Kingdom Quebec Pennsylvania New York & New Jersey Population Studied Reported deaths from asbestos Cases of asbestosis in 1,247 autopsies with pneumoconiosis Asbestos textile workers, industry areas , 20 years ' or more exposure Reported deaths from asbestosis Chrysotile miners and mill workers with over 5 years ' employment Workers in asbestos products plant employed in 1938-39, aged 25-64 Insulating workers, over 20 years ' union membership No. of Workers 235 121 113 365 5,958 1,495 632 Years Followed 1924-1947 1922-1953 1924-1955 1950-1955 1940-1960 1932-1962 No. With Lung Cancer 31/235 (13.1%) 17/121 11/39 deaths 65/365 (17.8%) 9/187 deaths 19/186 deaths 45/255 deaths Comparison Groups Silicotics (1.32%) Silicotics (6.9%) 0.8 Expected en- Expected 5.61 Expected 6.6 Expected (continued) u> ------- APPENDIX TABLE 5 CANCER OF THE LUNG AMONG ASBESTOS WORKERS (Continued) Place California Dresden United States United Kingdom Bulgaria New York Pennsylvania Population Studied Insulating workers, mixed, 15 years in trade, aged 35-64 All asbestos trade mixed exposures Asbestos textile workers employed in 1948-1951, aged 15-64 Reported deaths from asbestosis Agricultural workers near an asbestos mine Asbestos insulators em- ployed more than 15 years, aged 40-80 Asbestos textile and friction workers No. of Workers 529 2,636 2,833 584 3,325 152 68 Years Followed 1954-1957 1924-1963 1951-1963 1924-1963 1962 1945-1965 1957-1962 No. With Lung Cancer 10/41 deaths 34/150 deaths 24/285 deaths 146/584 (25%) 155/3325 asbestosis 18/46 deaths 13/68 deaths Comparison Groups 2.8 Expected 11.4 Expected 11.9 Expected 3.1 Expected ------- APPENDIX TABLE 6 "ASBESTOS BODIES" IN CONSECUTIVE OR RANDOM AUTOPSIES Location Capetown Miami Pittsburgh Milan Tyneside Jerusalem Glasgow Finland Sweden Total Cases 500 500 100 100 311 100 100 264 34 % Posi- tive 26.4 27.2 41 51 20.3 26 23 57.6 35.3 % Positive by Aqe* <24 .5 (4.3) 0 0 (0) 0 (0) r"«M 0 1.5 (57) 0 25-34 2.4 (25.6) 0 5 (83) (< 0.3 (25) (14) 0 3.0 (57) 0 35-44 4.4 (28.4) 1 (16.1) 5 (46) 3 (14) 1.6 (19.2) t W «ff >){<- 0 3.8 (71) 0 45-54 4.6 (22.4) 3.4 (23) 3 (38) — -i >) 2.9 (17.3) 1 (12) 8.7 (55) 0 55-64 7.4 (31.6) 5.6 (27.2) 13 (54) 30 (60) 4.8 (18.5) . 7—5>«. (21) 4 (22) 20.0 (64) 11.7 (80) 65-74 7.4 (28.0) 9.2 (30.6) 8 (40) 7.7 (28.9) i n (30) 11 (32) 16.7 (58.7) 14.7 (25) >75 90 (31.9) 6 (30) 18 (66) 2.9 (15) - V ... .>) 7 (19) 3.8 (34.5) 18.8 (43) Sex % Positive* Female 7.8 (20) 8 (20.4) 16 (34) 16 (44) 4.2 (13) 10 (29.1) 0 (0) 23.9 (54.3) 14.7 (38) Male 18.6 (30.4) 19.2 (31.6) 25 (47) 35 (54) 16.1 (25.5) 16 (22.2) 23 (37) 33.7 (60) 20.6 (33) Year of Study 1960 1961 1964 1966 1967 1967 1967 1966 1966 Refer- ence 214,216 214,216 40 67 11 184 188 167 82 (continued) ------- APPENDIX TABLE 6 "ASBESTOS BODIES" IN CONSECUTIVE OR RANDOM AUTOPSIES (Continued) Location Johannesburg San Francisco Belfast London Montreal New York .Total Cases 200 50 100 355 % Posi- tive 39.2 42 20 6 48 50.5 % Positive bv Aqe* <24 25-34 «•- 35-44 3 > (30) 45-54 •tfiJ R (50) 55-64 65-74 ^ 07 (50) >75 % Positive* Female 16 (36) 3.9 (29.8) Male 32 (57) 46.5 (53.7) Year of Studv 1965 1966 1965 1964 1966 1966 Refer- ence 234 43 60 102 7 195 *Numbers in parenthesis represent percentage of group-age or sex. ------- APPENDIX TABLE 7 COMPOSITION AND PROPERTIES OP ASBESTOS MINERALS 66 Approximate Formula Percentage of Manor Components Silica SiO2 Alumina A12O3 Ferrous Oxide FeO Ferric Oxide Pe2O3 Manganous Oxide MnO Calcium Oxide CaO Magnesium Oxide MgO Sodium Oxide Na2O Potassium Oxide K2O Carbon Dioxide CO2 Water of Crystallization H2O Chrysqtile 3MgO-2Si02'2H20 40.3 0.7 1.0 1.5 0.2 42.4 0.2 13.7 Crocidolite Na2O-3FeOFe2O- 8SiO2-H2O 51.4 20.3 17.5 0.1 0.8 1.4 6.2 0.4 1.9 Amosite 1.5 MgO-5.5FeO- 8SiO2'H2O 49.3 40.9 0.4 0.7 0.4 5.7 0.2 0.3 0.2 1.9 (continued) ------- APPENDIX TABLE 7 COMPOSITION AND PROPERTIES OF ASBESTOS MINERALS (Continued) Approximate Formula Trace Organic Impurities Oil-wax (mg/100 g fiber) Benzo ( a )pyr ene (ua/100 a fiber) Trace Inorganic Impurities (ug/g fiber) Pb Sn Ga Bi V Mo Cu Ti Ag Hi Zv Co Mn Cr Chrvsotile 3MgO-2Si02-2H20 4-7.6 none detected 2 <5 <2 <5 50 <2 35 50 <0.2 5,000 (1,000-14,000) <200 <5 (<100) 130 (400-500) 1,000 (400-900) Crocidolite Na20-3FeOFe20- 8SiO2 'H2O 4-200 0.2-24 5 <5 <2 <5 <2 <2 7 50 0.2 <10 «100) 700 <5 (<100) 180 (200) 20 (<100) Amosite 1.5 MgO-5.5FeO- 8SiO2 *H2O 4-20 0.2-2.4 20 <5 2 <5 <2 <2 7 300 0.2 1,000 (<100) 1,000 <5 (<100) 7,000 (7,900) 150 (<100) 00 (continued) ------- APPENDIX TABLE 7 COMPOSITION AND PROPERTIES OP ASBESTOS MINERALS (Continued) Approximate Formula Radioactive Contaminants (liUc/g fiber) K40 Th238 Ra226 Chrvsotile Crocidolite Amosite 0.14 0.02 0.55 <0 . 01 0 . 05 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" Harsh to soft Very high Very good Poor Fair Good V to 6" Coarse but pliable Fair Good Good Fair CTi ------- APPENDIX TABLE 8 WORLD PRODUCTION OF ASBESTOS (Short Tons) 170 Location 1962 1963 1964 1965 1966 b,e North America Canada (sales) United States (shipments) 1,215,814 53,190 South America Argentina 203 Bolivia (exports) . . 56 Brazil 4,900a Europe Austria 503 Bulgaria . 1,323C Finland^ 10,869 France 28,034C Greece Italy 60,860 Portugal U.S.S.R. ....... 710,000a'c Yugoslavia 7,401 Africa Botswana ....... 2,375 Kenya 212 Mozambique 370 Rhodesia, Southern . . 142,195° South Africa 221,302 Swaziland ...... 32,830 United Arab Republic . 606 1,275,530 1,420,769 66,396 101,092 365 10 l,440f 638 1,323C 10,201 26,094C 74 63,016 29 755,000a'c 9,074 2,368 78 142,254° 205,744 33,350 192 542 7 l,430a'c'f 1,433G 11,611 24,289C 65a 75,573 810,000a'c 9,280 2,161 204 153,450 215,592 39,862 1,739 1,387,555 1,479,281 118,275 125,928 243C 3 1,204 1,433 13,307 7,506C 85a 79,214 53C 865,000 10,585 888 136 176,149° 240,752 40,884 3,225 24 Oc 4 1,820 1,430* 13,250 7,720a 85a 90,464 10 925,000a 8,411 880a 73 175,000a 276,597 36,142 2,057 (continued) ------- APPENDIX TABLE 8 WORLD PRODUCTION OF ASBESTOS (Continued) (Short Tons) Location Asia Cyprus India Japan Korea , South .... Philippines Turkey Oceania Australia New Zealand World Total3 . . . 1962 100,000 22,391 1,865 15,407 1,333 1,037 525 709 18,416 457 2,655,000C 1963 110,000 19,962 3,038C 18,210 2,120 421 604 408 13,374 439 2,760,000C 1964 130,000 13,755 3,710C 17,979 1,402 586 526 1,291 13,545 3,050,000C 1965 140,000 17,622° 4,989 16,451° 1,710C 883 1,376 11,647 3,140,000C 1966b'S 140,000 24,449 7,646 17,067 687 721 1,258 13,472 3,350,000 aEstimated. Preliminary. c Revised. Asbestos 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. ^Includes asbestos flour. ------- APPENDIX 72 TABLE 9 THE PRODUCTION AND APPARENT CONSUMPTION OF ASBESTOS IN THE UNITED STATES41'170'171 Quant d Year 1967 1966 1965 1964 1963 1962 1961 1960 1959 1958 1957 1956 1955 1950 1945 1940 1935 Production 123,190 125,928 118,275 101,092 66,396 53,190 52 , 814 45,223 45,459 43,979 43,653 41,312 50,431 .ties in Short Tons Imports 645, 726, 719, 739, 667, 675, 616, 669, 713, 644, 682, 689, 716, 110 459 559 361 860 953 529 945 047 331 732 910 480 Values (X Exports Consumption 47, 46, 43, 27, 10, 2, 3, 5, 4, 3, 2, 2, 7, 1,000) 710 720,580 996 805,391 126 794,708 147 813, 044 724, 949 726, 799 (665, 525 709, 461 754, 026 685, 893 723, 950 782, 001 759, 727, 378, 270, 170, 306 212 194 440) 193 045 284 492 272 910 002 030 000 000 Exports Year 1967 1966 1965 1964 1963 1962 1961 1960 1959 1958 1957 1956 Production $11 11 10 8 5 4 4 4 4 5 4 4 4 ,100 ,056 ,162 ,143 ,108 ,677 ,347 ,231 ,391 ,127 ,918 ,742 ,534 Imports $66 73 70 72 61 64 (63 63 65 58 60 61 59 ,000 ,100 ,457 ,973 ,739 ,112 ,000) ,345 ,006 ,314 ,104 ,939 ,339 Asbestos $6 5 5 3 1 1 ,030 ,763 ,294 ,199 ,304 598 759 857 793 424 350" 375 ,497 Asbestos Products $21,963 19,139 16,288 16,267 14,274 13,233 15,223 14,181 12,464 ------- APPENDIX TABLE 10 REGIONAL DISTRIBUTION OP ASBESTOS MINING AND PROCESSING (Ranking and Production) 170,171 Rank 1 2 3 4 State 1960 Vt. Ariz. N.C. Calif. 1964 Calif. Vt. Ariz. N.C. 1966 Calif. Vt. Ariz. N.C. Quantity. (Short Tons) 1964 55,041 * * * (55,041) 1965 74,587 * 3,469 * (78,056) 1966 81,671 * * * (81,671) Value (X 1,000) 1964 $4,419 * * * (4,419) 1965 $6,177 * 441 * (6,177) 1966 $6,945 * * * (6,945) *Data withheld to avoid disclosure of producer's confidential information to the Bureau of Mines. 00 ------- APPENDIX TABLE 11 ASBESTOS MINES IN THE UNITED STATES, 1966 170 State California . / Vermont Arizona North Carolina Mineral Chrysotile Chrysotile Chrysotile Chrysotile Chrysotile Chrysotile Chrysotile Chrysotile Crocidolite Production Rank* 1 2 3 4 1 1 2 3 1 Name of Producer 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? LeTourneau Asbestos Corp.a Powhatan Mining Co. Location — Coun v or City of Mine Fresno County Fresno County Ca laveras County San Benito County Nap a Orleans County (Lowell) Salt River Valley (North of Globe) Yancey County tBurnsville) Processing Plant Near Mine Near Mine Near Mine Monterey County (King City) fRanlced by production only within the State. **Not in operation during previous years. ------- 75 APPENDIX TABLE 12 APPARENT ASBESTOS CONSUMPTION, 1965170 (In Thousands of Short Tons) Use Asbestos Industry Production Mining and Processing Asbestos in Products Textiles Cement Friction Materials Asbestos Paper Floor Tile Paints, Roof Coating, Caulks Plastics Miscellaneous Total Products World97 66 2,190 111 220 307 85 21 221 3,221 United States* 78 17 548 28 55 77 21 5 55 806 *Based on 25% of world consumption. ------- 76 APPENDIX TABLE 13 PROPORTION OF ASBESTOS IN VARIOUS ASBESTOS PRODUCTS170 Product Percent. Asbestos* Asbestos textiles Asbestos cement Friction materials and gaskets Asbestos paper and products Floor tile Other asbestos products 80-100 15-90b 30-80 80-90 10-30 c U.D. aChrysotile asbestos is used unless otherwise stated. ^15% to 90% chrysotile, with some materials containing as much as 85% amosite and small amounts of crocidolite and antho- phyllite. GThese products contain undetermined quantities of chrysotile, tremolite, actinolite, and anthophyllite. TABLE 14 QUANTITY AND VALUE OF ASBESTOS INPUT BY INDUSTRY 1963170 Product Asbestos textiles Asbestos cement Friction materials and gaskets Paper and products Floor tile Paint and coating fillers Plastics Other Total Quantity Short Tons (000) 66 2,190 111 220 307 85 21 220.7 3,220.7 Fraction of Total 0.02 0.68 0.04 0.07 0.09 0.02 0.01 0.07 1.00 Value $(000,000) 26.4 328.5 11.1 19.8 13.2 3.7 9.2 19.7 423.3 Fraction of Total 0.06 0.78 0.03 0.05 0.03 0.01 0.04 1.00 ------- 77 APPENDIX TABLE 15 POPULATION GROUPS WITH OCCUPATIONAL AND ENVIRONMENTAL EXPOSURE TO ASBESTOS108 Occupational Groups Nonoccupational 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 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 ------- 78 APPENDIX TABLE 16 ASBESTOS CONTROL EQUIPMENT95 Cost Data Asbestos Textile Industry3 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 Mines*5 Dust extraction equipment Total capital cost (TCC) ~ $ 360,000 (TCC/TCC of plant) x 100 ~ 27.5% Operating cost (per year) ~ $ 195,000 Specif ications Asbestos Textile Industry3 Volume of dust-containing air extracted from textile machines 1,000,000 ft /min or 700 ft^/min/operative Quantity of asbestos dust filtered per year (at above rate) 700 tons or 2.8 tons/working 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. ^Figures 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 TABLE 17 ANALYSIS OF ASBESTOS AND ASBESTOS PRODUCTS EXPORTS AND IMPORTS 170 Short 1965 Crude and spinning fibers Nonspinning fibers Waste and refuse i 1 24 17 ,251 ,221 ,523 Exports Tons 1966 1,455 28,017 17,218 Re-exports Dollars 1965 326 3,622 1,323 (000) 1966 325 3,973 1,414 Short 1965 50 81 Tons 1966 176 130 Dollars 1965 10 13 (OOP) 1966 30 21 Total Gaskets .and packing Brake lining Clutch lining (number) Textiles and yarn Shingles and clapboard Asbestos-cement Sub total Other products Total 42,995 46,690 5,271 5,712 131 306 23 2, If 3, 020, 5, 6, 732 065 864 794 465 101 2, 3, 2,246, 10, 4, 678 630 986 900 010 742 4, 4, 1, 1, 1, 1, 528 728 691 067 096 588 5, 5, 1, 1, 1, 1, 261 236 897 326 797 332 14,698 16,849 4,389 5,058 19,087 21,907 Imports Short Tons 1 1 5,000 5,000 113 231 5,114 5,232 Dollars (OOP) 1 2 4 37 44 8 52 51 1 2 1 41 45 11 56 1965 1966 1965 1966 Chrysolite Crude Spinning/ Textiles All Other Total Crocidolite Amosite 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 6,319 56,308 70,454 73,100 ------- 80 APPENDIX TABLE 18 SELECTED STATISTICS FOR THE ASBESTOS MANUFACTURING INDUSTRY41 (Employment Size) Number of Employees* 1-49 50-99 100-2,499 over 2,500 Total Number of Companies 39 6 10 18 73 Number of Plants 39 6 17 62 124 Number of Production Workers 308 231 2,445 12,754 15,738 Value of Shipments $ (000) 8,264 4,827 89,131 407,014 509,236 *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. ------- 81 APPENDIX TABLE 19 SELECTED STATISTICS FOR THE ASBESTOS PRODUCTS INDUSTRY41 Expenditures (in $000) New plant and equipment New structures New machinery and equipment Total Used plant and equipment Total 1958 2,419 10,418 12,837 428 13,265 1963 2,613 9,768 12,381 1,289 13,670 ------- APPENDIX 82 TABLE 20 ASBESTOS USES85 Textiles: Varieties used: Chrysotile, crocidolite, and in part amosite Yarns and Cordst 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 Sealing 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 rnelters' shields Slideways in the glass industry Handles and fire-doors Auto Parts Safes Protective walls Curtains, etc. (continued) ------- APPENDIX 83 TABLE 20 (Continued) ASBESTOS USES85 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 1ining Nonwoven: Clutch lining Transmission lining (continued) ------- APPENDIX 84 TABLE 20 (Continued) ASBESTOS USES85 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) AsbestosAcid-Resistant Compositions; Used mostly in chemical industry ------- 85 APPENDIX TABLE 21 1967 LIST OF MANUFACTURED ASBESTOS PRODUCTS85 Industry and Product Description Quantity Measure Miscellaneous Nonmetallic Mineral Products Asbestos Products Asbestos Friction Materials Brake Linings Woven, containing asbestos yarn, tape, or cloth Molded, including all nonwoven types Clutch facing Woven, containing asbestos yarn, tape, or cloth Molded, including all nonwoven types Asbestos-Cement Shingles and Clapboard Siding shingles and clapboard, including accessories Roofing shingles Asphalt Floor Tile Asphalt floor tile Vinyl Asbestos Floor Tile Vinyl asbestos floor tile Asbestos Textiles and Other Asbestos- Cement Products Asbestos textiles Yarn, cord, and thread Cloth Other asbestos textiles, including roving, lap, wick, rope, tape, carded fibers, etc. Asbestos-cement products Flat sheets and wallboard, all thicknesses converted to V basis Corrugated sheets Pipe, conduits, and ducts, including pressure pipe Linear feet Cubic feet Thousand pieces Thousand pieces Squares Squares Thousand square yards Thousand square yards Pounds Pounds Pounds 100 square feet 100 square feet Short tons (continued) ------- APPENDIX 86 TABLE 21 (Continued) oc 1967 LIST OF MANUFACTURED ASBESTOS PRODUCTS 3 Industry and Product Description Quantity Measure Asbestos felts Roofing-asphalt or tar saturated Other Other asbestos and asbestos-cement products, including millboard 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 Packing (for sealing moving parts) Asbestos, asbestos-metallic, and asbestos-rubber Insulation materials containing asbestos pipe insulation Cellular and laminated 85 percent magnesia Diatomaceous silica, calcium, silicate, expanded silica, and asbestos fiber Other pipe insulation Block insulation, including sheet and lagging 85 percent magnesia Diatomaceous silica, calcium silicate, expanded silica, and asbestos fiber Other block insulation, including celluar and laminated All other asbestos insulation Short Tons Short Tons Pounds Thousand pounds Linear feet Linear feet Linear feet Linear feet Thousand board feet Thousand board feet Thousand board feet ------- APPENDIX 87 TABLE 22 ASBESTOS PRODUCT MANUFACTURING PLANTS, 196341 vocation flew Hampshire Belknap Hillsborough Total lassachusetts Essex Franklin Middlesex Suffolk Worcester Total Connecticut Fairf ield Hartford Middlesex Total Slew York Albany Kings Orange Suffolk Total Sew Jersey Bergen Essex Hudson Mercer Morris Passaic Somerset Union Total Total Plants 1 1 2 1 1 2 2 1 7 3 1 1 5 1 3 1 1 6 1 3 1 2 1 3 4 1 \ 16 No. of Plants with Eraplo 1- 19 1 1 2 4 1 1 1 1 2 2 2 1 5 20- 49 1 1 1 1 1 1 2 50- 99 1 1 1 3 1 1 100- 249 1 1 1 1 1 2 3 250- 499 1 1 1 1 2 1 2 1 1 5 lament of 500- 999 1 1 1 1 1,000 or more 1 1 1 (continued) ------- APPENDIX 88 TABLE 22 (Continued) ASBESTOS PRODUCT MANUFACTURING PLANTS, 196341 Location Pennsylvania Elk Lancaster Montgomery Northampton Philadelphia Cit} Potter Total Ohio Cuyahoga Paulding Portage Ross Total Indiana Henry Huntington Kosciusko Lagrange Lake Rush Total Illinois Cook Kankakee Lake Will Total Michigan Wayne Total Total Plants 1 1 2 1 3 1 1 9 1 1 1 1 4 1 1 1 1 1 1 6 8 1 4 1 14 1 1 No. of Plants with Employment of 1- 19 2 1 3 1 1 1 1 5 5 1 1 20- 49 1 1 1 1 •^^MWMi 50- 99 1 1 100- 249 1 2 3 1 1 1 3 1 1 2 2 1 3 250- 499 1 1 1 1 2 2 1 1 4 500- 999 1 1 * 1,000 or more 1 1 (continued) ------- APPENDIX 89 TABLE 22 (Continued) ASBESTOS PRODUCT MANUFACTURING PLANTS, 196341 jocation Wisconsin Milwaukee Total Missouri St . Louis St. Louis City Total Cansas Barton Total Virginia Essex Frederick Norfolk City •Total Jorth Carolina Mecklenburg Union Total South Carolina Charleston Marlboro Total Georgia DeKalb Talbot troup Total Total Plants 1 1 2 3 5 1 1 1 1 1 3 2 1 3 1 1 2 1 1 1 3 No. of Plants with Emp! 1- 19 1 1 1 1 1 1 1 1 2 1 1 2 20- 49 50- 99 2 2 1 1 1 1 100- 249 2 2 1 1 1 250- 499 1 1 1 1 1 1 ovment of 500- 999 1,000 or more J— i continued j ------- APPENDIX 90 TABLE 22 (Continued) ASBESTOS PRODUCT MANUFACTURING PLANTS, 196341 Location Florida Dade Total Alabama Mobile Total Mississippi Hinds Union Total Louisiana Jefferson Orleans Total Texas Dallas EC tor Grayson Harris Hill Total California Alameda Contra Costa Los Angeles Orange Sacramento San Benito San Joaquin San Mateo Santa Clara Total JNITED STATES TOTAL Total Plants 1 1 1 1 1 1 2 3 3 6 2 1 1 3 1 8 2 1 9 1 1 1 1 1 1 18 124 1- 19 1 1 1 1 2 1 3 1 1 1 1 1 5 40 No, 20- 49 1 1 1 2 3 10 of Plants with Employment of '56- 99 1 1 1 1 1 3 13 100- 249 1 1 2 1 3 1 2 1 4 4 1 1 6 34 250- 499 1 1 2 1 1 1 1 21 500- 999 4 1,000 or more 2 ------- 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? 218 Timbrell has studied the deposition of fibrous material in the respiratory system. Fibers 50 or even 200 n long are found in the lungs because the free-falling speed depends largely on the diameter. Thus, particles less than 3.5 [i (most asbestos particles are less than 0.5 M) 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 M, 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 Society204 as fibers less than 200 M. long, less than 3.5 [1 in diameter, and having a length-to- breadth ratio of 3:1. Only the fibers longer than 5 n in length are counted. ------- 93 TABLE 23 PENETRATION OF FIBERS THROUGH NASAL HAIRS218 Length of Fiber (microns) 0.5 50 100 150 200 250 300 350 % Penetration through Nasal Hairs 1st Stage 100 75 53 31 26 20 17 14 2nd Staqe 100 57 24 10 5 3 2 1 3rd Stacre 100 42 11 3 1 229 Walter 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 [ig contain 5 x 10 particles of asbestos per |-ig. From this conversion factor the threshold "limit value for asbestos can be calculated* as approximately 350 |-ig/m (5 mppcf). TABLE 24 PARTICLE-MASS RELATIONSHIP OF ASBESTOS AS A FUNCTION OF FIBER LENGTH Total Concentration^ _ f-**y/ m Particles*/cirr (approx) 100 200 400 600 100 400 1,000 2,500 Incineration Residue Ug/nr (approx) 50-60 200-300 700-800 1,800-2,000 Fiber Length in Microns (approx) < 150 < 500 < 700 <10,000 *Particles counted with a konimeter. *5 mppcf=177 x 106 p/m3=350 |ag/m3. The concentration estimated in air is 600-6,000 p/m3=1.2 - 12 x 10~* ------- 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 (J. and shorter than 200 )a with diameters less than 3.5 H . ------- |