Document MM9Ey4JQavQvv9XxYgxL2MRbL

From The Desk Of JOHN MYERS TO: W. C. Thurber S. L. Baye E. A. Grimes This may be of interest or value. The AIA/NA "spent" about $50,000 with K & E cm this and arranged for a lot of presentations. The full proceedings are available - let me know if you want them. V / V "CALIDRIA" ASBESTOS UCC 001318 m ASBESTOS INFORMATION ASSOCIATION 1 745 Jefferson Davis Highway Crystal Sauare 4 Suite 5C9 Arlington Virginia 22202 (703l 9'?-1. ISO August 6, 1982 Dr. J. Stefan Dupre, Chairman Royal Commission on Matters of Health and Safety Arising from the Use of Asbestos in Ontario 180 Dunaas Street West 22nd Floor Toronto, Ontario Canada M5G 1Z8 Dear Chairman Dupre: The Asbestos Information Association/North America has appreciated the opportunity to participate in the proceedings of the Royal Commission. In order to assist the Commissioners as they move toward the drafting of a final report, our counsel have prepared the enclosed summary of the evidence presented to the Commission on health, monitoring and regulatory issues. The summary includes occasional references to asbestos literature not formally in the Commission's record as testimony or exhibits. Most of this litera ture is no doubt in your library; but, if there are any publications cited that are not readily available, we would be glad to supply them to the Commission. (JCC 001319 Dr. J. Stefan Dupre, Chairman August 6, 1982 Page Two I am enclosing copies of the summary for the active interested parties in Toronto and ask that you please deliver them. Respectfully yours Enclosures cc w/ enc.: Dr. Dr. Mr. Ms. Mr. Mr. Ms. Mr. Mr. Mustard Uffen Laskin Kahn Casgrain Leaerer Jolley McCombie Starkman Executive Director UCC 001320 ROYAL COMMISSION ON MATTERS OF HEALTH AND SAFETY ARISING FROM THE USE OF ASBESTOS IN ONTARIO SUMMARY OF THE PHASE II HEARINGS ON HEALTH, MONITORING AND REGULATORY ISSUES August 6, 1982 Edward W. Warren Timothy S. Hardy Kirkland & Ellis 1776 K Street, N.W. Washington, D.C. 20006 Counsel for the Asbestos Information Association/ North America UCC 001321 ONTARIO ROYAL COMMISSION ON ASBESTOS INTRODUCTION TO TEE COMMENTS OF AIA/NA ON HEALTH, MONITORING AND REGULATORY ISSUES In the course of the proceedings before the Ontario Royal Commission on Asbestos, a substantial segment of the world's experts on the health effects and monitoring of asbestos have appeared. Although there were clearly differ ences among the witnesses, and although many issues were deemed still unresolved, consensus was reached in important areas that should serve as the basis for determination of a rational societal policy toward asbestos: All human health effects of asbestos are dose-related, and present-day health effects are attributable to high, often uncontrolled, exposures of the past. Asbestos exposures today are orders of magni tude lower than the historical exposures upon which knowledge of ill effects is based. Although the potential health effects of the lower exposure levels found in the workplace today cannot be determined definitively, the best scientific evidence indicates the risks are minimal, if not insignificant. Even conservative overestimates of the health effects of asbestos at low exposure levels based on linear, non-threshold assumptions about the dose-response relationship predict that properly controlled asbestos use today poses de minimis, or well within acceptable level, occupational risks. Often expressed fears about asbestos risks to the general population have been widely exaggerated; no public health risk need exist from the continued proper use of modern encapsulated and locked-in asbestos products. UCC 001322 2 Based on these principles, a rational societal policy toward asbestos recognizes that the substance continues to serve an important role in many applications where it can be used with minimal or no risk. At the same time, the evidence demonstrates that all uses must be closely scrutinized to minimize unnecessary exposures. In order to assist the Commission in understanding and synthesizing the substantial record that has been accumu lated, we present this Summary. The Summary covers the following questions which are before the Commission: (1) What is known about the biology of asbestos fibers: their respirability, their deposition and disposi tion in the body, and the effect on such fibers of the body's clearance and immune mechanisms? (2) What is known about the pathogenicity of asbestos fibers and the mechanisms by which they cause human disease? (3) Do asbestos fibers differ, given varying chemical compositions, sizes and dimensions, in their biologic and pathogenic significance? (4) What diseases have been found to be associated with asbestos exposure and with what dose-response relationships? (5) To what extent do other factors, particularly smoking, account for disease among asbestosexposed persons? (6) What conclusions can reasonably be reached in predicting the risks of asbestos exposure at the lower levels found in the workplace today, and in general population exposure? Following our discussion of the exposure and health effects evidence, we suggest to the Commission a series of societal measures that appear appropriate to minimize asbestos risks in the future. These measures include: UCC 001323 3 Continuing efforts to employ all reasonable, technologically feasible methods to control asbestos fiber emissions in fixed-site mines and mills and primary and secondary manufac turing facilities and to monitor through use of the membrane filter method such emissions to ensure achievement of acceptably low exposures. Employment of recommended .work practices in non-fixed workplaces -- such as construction sites -- in order to eliminate excessive fiber emissions. An educational labeling scheme for asbestoscontaining products to ensure their proper handling. Promotion of smoking cessation programs among asbestos-exposed workers. Continuing surveillance and research to answer many of the more particular, but still unresolved, questions concerning asbestos. Our proposal does not include the government-mandated phase-outs or bans of asbestos use that have been suggested in some quarters. Such regulatory steps cannot be justified given the extensive evidence supporting the feasibility of continued safe use. Appropriate measures are now being used, and further measures could be employed, to control asbestos fiber emissions. It should be the role of Govern ment to ensure that such measures are employed whenever asbestos is used. However, given -the minimal risks when such controls are used, the marketplace should be relied upon to decide whether the cost of such practices is jus tified by the necessity or desirability of asbestos use. UCC 001324 ONTARIO ROYAL COMMISSION ON ASBESTOS SUMMARY OF THE PHASE II HEARINGS ON HEALTH, MONITORING AND REGULATORY ISSUES TABLE OF CONTENTS EXECUTIVE SUMMARY Fiber Type Asbestos Epidemiology Risk Extrapolation Environmental Risks Monitoring Policy Implications I. THE VERSATILITY AND USEFULNESS OF ASBESTOS AND INDUSTRY'S SUBSTANTIAL PROGRESS TOWARD CONTROLLING HUMAN EXPOSURES A. Commercial Uses of Asbestos B. Human Exposures to Asbestos Fibers 1. The Ubiquity of Asbestos in the Natural Environment 2. Heavy Asbestos Exposures in the Workplace in the Past 3. Lowered Asbestos Exposures in the Workplace Today 4. Very Low General Population Exposures II. THE PHYSIOLOGY OF ASBESTOS-RELATEDDISEASE A. Fiber Physics, Respirability and Deposition B. Clearance and Defense Mechanisms Pa9e i ii iii vi ix x xiii 1-1 1-2 1-8 1-9 1-13 1-19 1-22 II-l II-3 II-8 UCC 001325 2 C. Disease Mechanisms D. The Role of Fiber Chemistry E. Fiber Types III. THE ASBESTOS EPIDEMIOLOGY A. Principles of Interpretation B. The Important Epidemiology Studies 1. The McDonald Canadian Chrysotile Miner and Miller Studies 2. The Weill Louisiana Asbestos-Cement Workers Studies a. The Morbidity Study b. The Mortality Study 3. The Newhouse and Berry Friction Plant Study 4. The Enterline Factory Worker Study 5. The Rochdale Textile Factory Studies a. The Morbidity Study b. The Mortality Study 6. The Toronto Asbestos-Cement Plant Studies a. The Morbidity Study b. The Mortality Study 7. The Dement Textile Factory Study 8. The Paterson Amosite Insulation Factory Study 9. The Selikoff Insulation Worker Studies 10. The Anderson Family Member Study Page 11-13 11-20 II-24 III-l 111 -3 111-9 III-9 III-21 111-21 III-25 111-30 111-33 III-41 111-42 III-46 III-50 111-55 111-57 111-59 111-68 111-71 111-74 UCC 001326 3 C. Synthesis of the Asbestos Epidemiology 1. Asbestosis: A Problem of the Past 2. Lung Cancer: A Problem Related to Smoking a. Studies Not Finding Risk b. Less than Effective Doses c. The Role of Smoking d. Fiber Type 3. Mesothelioma: A Rare Disease Not Solely Related to Asbestos a. Diagnostic Difficulties b. Other Causes c. Dose-Response Relationships d. Non-Occupational Exposures e. Fiber Type Differences 4. Other Cancers: A De Minimis Problem a. Gastrointestinal Cancer b. Laryngeal Cancer IV. OCCUPATIONAL RISK ASSESSMENT A. Measures of Risk B. Risk Extrapolation Principles and Data Selection 1. Choice of Model 2. Choice of Data 3. Choice of Conversion Factors Page 111-77 111-79 111-88 111-88 111-89 111-92 I11-99 II1-102 111-102 I11-104 111-106 111-112 111-121 111-128 111-129 III-133 IV-1 IV-2 IV-10 IV-11 IV-17 IV-29 UCC 001327 -4- C. Determination of Current Exposures 1. Exposure Measurement 2. Expected Exposures 3. The Exposed Population D. Predicted Risks V. THE ABSENCE OF GENERAL POPULATION RISKS A. Ambient Exposures B. Exposures in School Buildings VI. MONITORING WORKPLACE AND ENVIRONMENTAL ASBESTOS CONCENTRATIONS A. Workplace Monitoring 1. Use of the Membrane Filter Method for Routine Occupational Monitoring 2. Absence of a Feasible Alternative for Routine Monitoring a. Scanning Electron Microscopy b. Tranmission Electron Microscopy c. Automatic Counting and Magnetic Alignment Techniques 3. Substantial Variability of the Membrane FilterMethod a. Measurement Variability b. Implications for Establishing Occupational Standards c. Achievement of Very Low Workplace Concentrations B. Environmental Monitoring 1. Absence of an Appropriate Standardized Method 2. Asbestos Concentrations inOntario Page IV-38 IV-3 9 IV-41 IV-45 IV-48 V-l V-l V-ll VI-1 VI-1 VI-2 VI-12 VI-13 VI-17 VI-19 VI-22 VI-22 VI-29 VI-37 VI-38 VI-39 VI-44 UCC 001328 5 VII. APPROPRIATE CONTROL MEASURES FOR FUTURE ASBESTOS USE A. Asbestos Safety in the Mines andMills B. Asbestos Safety in Manufacturing C. Work Practices for Non-Fixed Site Workplaces D. Labeling to Promote Safe Handling E. Smoking Cessation Programs Pa^e VII-1 VII-3 VII-6 VI1-13 VII-21 VI1-23 UCC 001329 ONTARIO ROYAL COMMISSION ON ASBESTOS EXECUTIVE SUMMARY OF THE AIA/NA SUMMARY OF THE PHASE II HEARINGS ON HEALTH, MONITORING AND REGULATORY ISSUES In an era of increasing public concern about carcino gens, asbestos has often been a centerpiece of public atten tion. Because the adverse health effects of asbestos gen erally develop only twenty or more years after initial exposure, the consequences of very high occupational expo sures during World War II and before have become apparent only in recent years. The medical consequences of these very high occupational exposures must, however, be distin guished from the related, but distinct, issue of whether the much lower asbestos exposure levels prevalent today pose a significant risk to either workers or the general population. Consideration of this issue requires a detailed examination of the evidence on exposures to and health effects of asbestos. Asbestos is a naturally occurring mineral found in many parts of the world. Through natural processes, it spreads to ambient air and waters with the result that human exposure is virtually unavoidable. Although very high occupational exposures to asbestos occurred in the past, improved con trols in modern manufacturing processes and changes in the products in which asbestos is used have vastly reduced exposure today. Within the past decade, most mines and -1UCC 001330 manufacturing facilities have achieved continued substantial decreases in exposure levels. As a result, most asbestos workers experience exposures well below existing governmental standards. Almost all products now marketed employ asbestos embedded in a matrix that eliminates or substantially limits fiber release. As a result, little likelihood of harmful exposure exists for product users. General population exposures to asbestos, where they exist at all, are several orders of magnitude lower than today's workplace exposures. Fiber Type Since the associations between high asbestos exposures and asbestosis, lung cancer and mesothelioma were first discovered, medical research has concentrated on trying to establish what size and shape and which type asbestos fibers are most dangerous. Animal research has essentially estab lished that fibers longer than eight microns and less than one micron in diameter are the most pathogenic. Distinc tions among the major fiber types (chrysotile, amosite and crocidolite) are less clearly established. Apparently diverging medical data complicates determination of relative pathogenicity. Although animal and tissue culture experi ments tend to demonstrate more disease-causing potential for chrysotile, the human evidence has usually shown greater disease, particularly mesothelioma, among persons exposed to crocidolite and amosite. - 11 UCC 001331 Asbestos Epidemiology The many epidemiology studies of workers with high asbestos exposures in the past have confirmed associations with asbestosis, lung cancer and mesothelioma and have also strongly suggested that very little if any risk still exists at today's much lower exposures. These studies have also emphasized the extent to which smoking accounts for much of the past disease. Asbestosis, a fibrotic lung condition that may lead to death in its advanced stages, has occurred almost exclusively among very heavily exposed workers. This chronic disease is closely related to sustained high exposures and at its advanced clinical stages is very unlikely to occur at today's exposure levels -- even among lifetime asbestos workers. Threshold levels below which asbestosis symptoms have not been found have been established in the asbestos-cement worker studies of Dr. Weill. Even in other studies where no clear thresholds have emerged (the Canadian miners and Rochdale, England textile workers), very little asbestosis would be predicted based on extrapolations from the expo sures of those cohorts to workers at today's exposure levels. Continuing surveillance of worker populations in Australia and the United States demonstrates the declining incidence of asbestosis in populations being exposed to lower and lower asbestos concentrations. The consensus opinion of - 111 UCC 001332 the experts who appeared before the Commission was that asbestosis is not a significant occupational health concern for the future. Although greatly increased lung cancer rates have been found among some asbestos workers, the amount of disease is closely related to worker smoking habits, as well as the high doses experienced in the past. Although definitive evidence has not yet been developed of a dose below which no increased risk exists, absence of increased mortality due to respiratory malignancy in several large cohorts for the persons with lower -- although still much higher than modern -- exposures provides strong support for concluding that no substantial hazard exists for modern asbestos workers. The medical evidence strongly suggests that any remaining risk is very small, and, for non-smokers, close to non-existent. Several large cohorts of asbestos workers have failed to exhibit increased lung cancer risks. The subcohort of the Canadian miners with exposures below approximately 20 fibers/cc for twenty years, the Louisiana asbestos-cement workers with exposures below 100 mppcf-years, and the asbestos friction material production workers studied by Newhouse and Berry have not exhibited increased lung cancer risks -- despite their greater than current worker exposures. Although other studied cohorts have exhibited some lung cancer risks at such exposure levels, these three well-documented studies -each of which specifically focused attention on dose-response - IV - UCC 001333 relationships -- suggest strongly that the much lower expo sure levels found in industry today are so low that any remaining risks are too small to be detected. Central to any assessment of the increased lung cancer risk of asbestos is the predominant role of smoking in determining risk. Although there is some evidence that lung cancer risks are increased for non-smokers, almost all lung cancer has occurred among smokers. At today's asbestos expo sure levels, reduction of lung cancer incidence is far more dependent on termination of smoking than on elimination or reduction of asbestos exposure. Mesothelioma is a rare tumor of the pleural and perito neal tissues. Although often associated with asbestos exposures, mesothelioma also occurs in the absence of asbes tos exposure. Like asbestosis and lung cancer, mesothelioma has been shown to be related to dose and to have occurred primarily among heavily exposed persons. Its future occur rence among persons exposed at today's occupational levels is likely to be quite rare. Unwarranted fears of mesothelioma risks to the general population have been generated by scattered references to individual cases allegedly caused by casual exposures. In fact, all the existing evidence suggests that, on the one hand, those cases discovered among worker families were probably due to quite substantial exposures caused by con tact with workclothes and prolonged household reentrainment -vUCC 001334 of fibers, and, on the other hand, cases where asbestos exposures were in fact casual are most likely attributable to the natural background rate for this disease. At today's exposure levels, the mesothelioma risk predicted, even if based on conservative extrapolation models, would be quite low. Although some studies have reported associations between asbestos exposure and other forms of cancer, the overall evidence is equivocal. The scientific evidence demonstrates that such cancers normally occur only after very high expo sures and account for a minimal amount of asbestos-related disease. Risk Extrapolation Because asbestos related diseases typically take more than 20 years to become manifest, no groups of workers exist who have been studied for long enough to provide documented evidence of the risk, if any, at current low exposure levels However, using risk extrapolation methods, it is possible to set upper limits on the magnitude of such risks. All human activities, including employment, involve risk. Man accepts risks every day, often without recogni zing their magnitude. Many studies have quantified commonly accepted risks in order to place in context the risks posed by use of substances such as asbestos. Once risks are placed in such a context, rational societal decisions can be - vi UCC 001335 made about the efficacy of risk reduction measures. In order to make such assessments, it is necessary to project - the asbestos dose-response relationship to the low exposure levels prevalent in current asbestos use. Dose-response relationships for asbestos-related diseases have been found to be linear at those high doses for which empirical data exist. It has thus often been suggested that a linear relationship will continue to lower doses. Such linear extrapolations, though, have not been empirically demonstrated and most likely overstate risks at low exposure levels. Their use thus sets an upper limit on potential risk. Central to predicting future risks are determinations of past exposures among the studied cohorts. Concerted efforts to construct individual exposure profiles have been made for asbestos worker cohorts by Drs. McDonald, Weill, Enterline, Newnouse and Berry, Finkelstein, and Dement. It is from their studies that the primary data for extrapolat ing risks must be sought. Although most of these cohorts' exposures were initially measured in particles, not fibers, adequate work has been done on conversion to provide mean ingful guidance for current regulatory purposes. Also central to predicting current risks is an under standing of current exposure levels. Under the two fibers/cc standard that prevails in most Western nations, average exposure levels well below that standard exist for most - Vll - UCC 001336 workers. Indeed, other than for the relatively small number of workers in mining and milling and primary and secondary manufacturing, most occupational exposures to asbestos are intermittent, and, when recommended work practices are employed, de minimis. For such workers, average exposures are thus many times lower than the two fiber standard. Among the entire worker population in Canada or the United States, therefore, only a few thousand workers are likely to have lifetime exposures of more than 10 fiber-years; most workers will have lifetime exposures below 1 fiber-year. Applying extrapolation to the best available data indicates that the current risk to asbestos workers is within the range of risks faced every day by most workers. Once the significant part of that risk due to cigarette smoking is taken into account, the risk is well below most other occupational risks. The disease risk predicted from the asbestos epide miologic studies varies to some extent from study to study. Some of the variance can be explained by methodological differences among the studies, but some of the variation may also be due to true differences in disease potential in various asbestos operations. At one end of the spectrum, the risks predicted from the chrysotile mining experience is so low at current exposure levels as to leave little ques tion about conclusions that mining and milling operations are acceptably safe. Some of the primary manufacturing - vni - UCC 001337 studies predict similarly very low risks, but a few studies predict higher risks. Although all such differences cannot be clearly reconciled with the present state of knowledge, even the higher risks predicted by these latter studies fall within the range of normally accepted occupational risks. If that proportion of the risk attributable to lung cancer caused by smoking is clearly delineated, the predicted asbestos risk is toward the low end of accepted occupational risks even when determined based on the studies predicting higher risks. Environmental Risks Despite the fears generated by the media, the opinion of most scientists, as well as expert governmental-scientific bodies, has been that no significant risk due to asbestos exists for the general public. Risk extrapolation methods can also be used to establish upper limits on the asbestos risks that theoretically would exist for the general popula tion. Those risks are well below a number of commonplace risks faced daily by the general public. The absence of evidence of a general population risk applies to both airborne and waterborne asbestos. Although serious medical consequences have been associated with heavy exposures through asbestos inhalation, no such body of evidence exists for ingestion. Animal studies of asbestos ingestion, including on-going state-of-the-art bioassays, - ix - UCC 001338 have failed to demonstrate any carcinogenic or other health risks. Similarly, the human epidemiologic evidence predomi nantly fails to find any association between ingestion and cancer. Monitoring In addition to the medical evidence, considerable testimony was presented to the Commission on the monitoring of asbestos. This testimony provides further important guidelines for governmental policies on asbestos control. The membrane filter method is a practical and effective technique for conducting the large volume of routine occupa tional monitoring required in the asbestos industry. It has been adopted throughout North America and Europe, is the basis for current occupational standards, and can be related to the available epidemiological evidence. The advantages of membrane filter monitoring include its relatively low cost and simplicity, the ready availability of necessary equipment and skilled operators, and the significant pro gress made in the last decade toward methodology standardi zation . The membrane filter method also has several important limitations. The basic method does not distinguish among asbestos fiber types or between asbestos fibers and other fibers; and it provides only an index of fiber concentra tions, because it does not count very short or very thin -x UCC 001339 fibers. However, such discriminations often are unneces sary, and, where needed, can be made by supplementing mem brane filter measurements in mixed fiber environments with occasional electron microscope characterization of dust cloud constituents. There is therefore no reasonable basis for change in the currently-employed monitoring system. * Potential alternatives to the membrane filter technique are infeasible for routine monitoring. Electron microscopy may be useful to characterize fiber proportions in mixed fiber environments, but no standardized method for either scanning or transmission electron fiber counts has been developed. Further, electron microscopy measurements cannot be related to membrane filter results or to the existing health evidence; capital costs are very high; insufficient qualified laboratories and technicians exist to meet exist ing monitoring needs; and, except for scanning electron microscopy at low magnification (offering little advantage over membrane filter measurement), operating costs per sample are very high. In establishing workplace standards based on membrane filter monitoring, the substantial measurement variability, as well as day-to-day variations in workplace concentrations, must be considered. Given these sources of variability, and the generally recognized 0.1 fiber/cc detection limit for the membrane filter method, the lower bound for possible asbestos standards is in the range of 0.5 to 1 fiber/cc. - xi - UCC 001340 With any lower standard, employers and enforcement officials would be unable to determine compliance status with reason able confidence. Standards in the range of one to two fibers/cc can be implemented using membrane filter monitor ing, if employers allow for variability, by maintaining average workplace concentrations well below mandatory standards. Membrane filter monitoring can be used, along with occupational exposure standards consistent with the method's accuracy, to achieve highly protective workplace conditions. Because employers must measure well below the occupational standard to obtain reasonable assurance of compliance, average workplace concentrations will be maintained well below mandatory standards. Outside the workplace -- in ambient air and water, or in buildings -- the membrane filter method is inadequate to provide meaningful monitoring results. The extremely low asbestos concentrations found in such settings fall well below the membrane filter detection limit. In addition, membrane filter fiber counts outside the workplace would be meaningless, because the membrane filter method does not distinguish between asbestos fibers and the many other fibrous materials found in the general environment. Although electron microscope techniques meet some of the technological requirements for environmental monitoring, there is no standardized electron microscopy method and no - xii UCC 001341 basis for relating electron microscopy results to the health evidence on asbestos. There is therefore no basis for establishing environmental standards or for comparing results from different laboratories quantitatively. Nevertheless, electron microscopy monitoring results of air and water -- which are qualitatively useful when compared with similar background measurements -- demonstrate no cause for concern. Both in England and Ontario, investigators have recently determined that fiber concentrations in build ings with asbestos insulation do not exceed background levels found in outdoor measurements -- except where insula tion has recently been removed. The present evidence thus shows little need for environmental asbestos control stan dards . Policy Implications The comprehensive medical evidence on asbestos that allows estimation of the extent of risk, if any, posed by current asbestos mining, manufacturing, installation and use, makes it possible to design an appropriate societal policy for the substance. Such a policy recognizes both the value of asbestos as a versatile mineral and the necessity for educational and control measures to minimize human exposures. A variety of government initiatives would be useful to guarantee reasonable control of fiber emissions. - xm - UCC 001342 First, in the mining and milling of asbestos, continua tion of the extensive control measures that have been adopted in recent years is necessary. The well-documented mining epidemiology evidence demonstrates that such levels provide an acceptably safe workplace. Second, continuation of the control measures that have succeeded in recent years in vastly reducing exposure levels in the manufacture of asbestos-containing products (includ ing, inter alia, the most significant uses -- asbestos-cement products, friction materials, and flooring) is necessary to maintain a safe workplace. Although variations exist among the risk estimates derived from manufacturing cohorts, the much-reduced exposure levels common today do not pose signi ficant risk of disease. Third, new inducements or requirements to increase use of recommended work practices in the installation and removal of asbestos-containing products are desirable. Although workers in industries where exposure to asbestos is infre quent and intermittent are unlikely to have cumulative asbestos exposures in the ranges experienced by workers exposed on a daily basis, it is nonetheless advisable to control unnecessary exposures. Most such non-fixed site exposures can be dramatically reduced through proper work practices. Similar cost-effective work practices can and should be employed in fixed site garage work with asbestos friction products. - xiv UCC 001343 Fourth, educational labeling of raw asbestos fiber and many asbestos-containing products to describe and encourage the use of safe work practices will greatly reduce the potential for inadvertent and unnecessary fiber emissions. Fifth, smoking cessation programs can greatly diminish the risk of disease, especially lung cancer, among asbestos workers. Indeed, with asbestos levels much reduced in the workplace today, considerably more will be accomplished by such anti-smoking programs than by further reductions or elimination of asbestos exposure. Finally, continued medical and technological research is warranted to fill existing gaps in knowledge of the health effects of asbestos and to improve further the capa bility of minimizing fiber release while still making bene ficial use of this versatile mineral. - xv - UCC 001344