Document bOYGBMjwj7mjj3vK8MZxqwvLD

THE ACTUAL CONTRIBUTION or AIRBORNE ASBESTOS FIBERS TO THE OCCUPATIONAL rrpocTmf or BY-STABDERS DURING SELECTED PROCESSIEG of ENCAPSULATED ASBESTOS SASEETS GASKET CUTTING WITH HAND SHEARS CARL A. MANGOLD, CIH ENVIRONMENTAL CONTROL SCIENCES. INC. BELLEVUE, WASHINGTON JANUARY 1989 ABSTRACT Asbestos'containing gasket stock can be cut to various shapes with industrial hand shears. The asbestos stock is first cut to a shape near the size of the gasket to be prepared. Then the shape desired is drawn or scratched on the gasket stock sheet. The shears are then used to cut the stock to the desired size. The bolt- holes are customarily cut with a hollow punch. New Garlock Inc. gasket stock # 900/7735 containing about 70* chrysotile is most often used for pipe flanges and machinery. One gasket was cut to shape and the bolt holes punched each hour for 8 hours, or the preparation of 8 gaskets^. This simulates the actions of a workman who must prepare the gaskets as needed during the work day. The air samplers placed on the operator and at S and 10 feet away from the operator recorded the release of chrysotile asbestos fibers in the air from this process. The operation was conducted in a clean room and very low ambient levels of natural asbestos. The results showed that; 1. The electron microscopy analyses for total chrysotile fibers averaged .006 structures/ccor less. Structures/cc is approximately equal to fibers/cc. i 2. The electron microscopy analyses for chrysotiie asbestos fibers greater than 5 micrometers in length and less than .25 micrometers in diameter were compared to the phase contrast microscopy method. The results averaged .002 structures/cc or less. The electron microscopy method is precise, determined that only chrysotiie was present, and is verification of the phase contrast microscopy method. 3. The phase contrast microscopy analyses revealed that the average concentration for fibers greater than 5 micrometers in length was .004 fibers/cc or less. The personal sample of the operator using the shears was .005 fibers/cc. Phase contrast microscopy is the only method specified for analyses in the Federal standard for asbestos. . The 8 hour time-weighted average to the operator and to those of by-stander in the enclosure are a fraction of the Federal standard of .2 fibers/cc. TABLE OF OOirUl-h ABSTRACT -TABLE OF CONTENTS BACKGROUND ENVIRONMENTAL EXPOSURES VOLUME OF ASBESTOS USED INSHIPYARDS EXPOSURES OF THE CONSTRUCTION AND SHIPYARD TRADES CURRENT ALLOWABLE LEVELS OFEXPOSURE CONTINUING EVALUATIONS U.S. NAVY GASKET REPORT VERIFICATION OF THE NAVYGASKET REPORT THE DILEMMA EXPERIMENTAL DESIGN REFERENCES RESULTS AND CONCLUSIONS 1 t 2 5 ? 6 9 10 11 13 IS 17 21 24 1 2. BACKGROUND: Asbestos is one of the most plentiful, useful, and cheap Industrial minerals. Because of Its high thermal stabriity and resistance to corrosion It appears In sore than 3,000 manufactured goods In the United States. Estimates are that at least 30,000,000 tons have been used In construction and manufacturing since the year 1900. This common use of asbestos has led to the exposure of millions of Americans at levels that may have a significant impact on their health. Today, large numbers of Americans are exposed to asbestos In industry as well as the environment where It occurs naturally. Most environmental exposures occurs in our cities, near industrial complexes, from soil high In asbestos content. In the water, and In the air from these sources. Therefore, most Americans receive at least some regular low level exposure throughout their lifetimes. In 1900, Dr. Churg (1) determined that most city dwellers retain a considerable amount of asbestos In their lungs in some state of clearance. The retained amounts can be in the millions of fibers just from living and working in the city where low level exposures to asbestos is commonplace. The concerns about the role of asbestos in the development of a lung disease: asbestosia, began in the United States in the 1930's and progressed slowly as more was learned about the pathogenesis of the disease. Most of 2 If the attention was centered on disabled workers with obvious work-related exposure patterns involving exposure to the raw fibers of the various forms of asbestos used commercially. Pew, if any, controls were followed so that time and intensity factors led to dose levels that precipitated various degrees of asbestosie. This continued until the 1960's when signs of asbestos-related cancers began to reshape thinking and action about the occupational exposures to asbestos. Today, the exposures of workers to asbestos have been markedly reduced through various aeans of voluntary controls and legislations that led to the first Federal standards In 1972. Since that tlae the permissible exposure levels of asbestos have been reduced through the regulatory processes In the United States. Zn 1964, Marr (2} concluded that asbestos-related disease was an important problem among insulators working in Naval shipyards. Bis assumptions were correct; however, the methods of assessment weakened the conclusions. Pioneer work was begun at Puget Sound Naval Shipyard (PSNS) in 1965, culminating In a conclusive report of exposure levels and medical findings by Mangold, Beckett 6 Bessmer (3,4). Most of the attention was directed at the products and the operations that produced high-level exposures to asbestos workers and associated trades, and because of the large volumes of asbestos used annually in the shipyard. The conclusions were that the threshold limit value (TLV) 3 was still too high at S Billions of particles per cubic foot (MFPCF), equivalent to about 50 fibers per cubic centimeter, and that Intermittent peak exposures were far sore important that previously recognized. Both conclusions have been corroborated by sore recent literature. About-1964, Sellkoff (5,6) and others reported the association of- exposure to asbestos with asbestos-related cancers and the effects of smoking. Zn 1978, Dr. Sellkoff (7) and a team of scientists published a protracted study of asbestos-related diseases which defined the latent effects of exposure and probable dose-response relationship based upon time and Intensity of exposure. The model formulated from high-level exposures was extrapolated to all levels of exposure however so small. But, J.E. Craighead, et.al. (B), M.R. Becklake (9) and W.J. Nicholson (10) all raised reasonable questions about the validity of the straight line approach because of the latency factors and ill-defined responses to low level exposure. Nicholson (10) further observed that the long lapse time from exposure to the onset of asbestosls, or asbestos-related cancers, creates difficulties in attempting to establish the true dose-response relationship. And, the diseases today were from decades past when few measurements of asbestos concentrations in the breathing zone of workers were made, exposures were high, and controls few. ' . Since that time Dr. Churg (1) has described the 4 relatively high levels of asbestos fibers in the lungs of city dwellers not occupationally exposed. This suggests a sigmoid, or HS" shaped curve, so often found where a lower no-effect level Is reached. Otherwise, millions of Americans receiving dally exposures to asbestos from the environment at low levels should show significant asbestos-related disease. They do not. Therefore, the assumptions that all levels of exposure have the same risk through the straight line dose-response model is extreme and without proof. It is based upon - extrapolation and assumption. The Occupational Safety and Health Administration (OSHA) used those assumptions in the 1972 Federal regulation for occupational exposure to asbestos (11) and subsequent downward revisions. In addition, they have made the assumption that all forms of asbestos, namely Chrysotlle, Aaosite, and Crocidolite, and sore recently less used commercial forms all produce asbestos-related disease at the same levels of exposure. More recent studies in 1988 by Dr. Churg and others (12,13) show that the potency of the various forms of asbestos are different related to the cancer producing effects. However, OSHA treats them alike; as does the Environmental Protection Agency (EPA) for regulatory control purposes. 2. ENVIRONMENTAL EXPOSURES: The amount of environmental exposure to natural forms of asbestos in the United States 5 I* is substantial. Asbestos, mainly Chrysotile, is common to the ambient air in the environment especially near mountainous regions in the United States. There are 22 States with major asbestos outcroppings that contribute substantial amounts of asbestos to the air, water, and the eroded soil. Many major cities, as Seattle, Washington may use drinking water for the population that contains 400,000 to 1,000,000 asbestos fibers per liter of water. Because the asbestos occurring naturally is so wide spread on the East and West coast and along the border with Canada, millions of Americans receive dally and substantial exposures to asbestos from birth from these natural sources. The increased activities in cities and the concentration of large numbers of the population on a dally basis causes even further Increases in exposures, some from manmade products such as clutches or brakes of vehicles. Zt is not uncommon to find airborne concentrations of asbestos in such communities at levels of about .002 flbers/cc of air, rising to occasional peaks of .02 flbers/cc or sore. The background levels of natural occurring asbestos in air is so prevalent that the EPA took into account the influence for clearance of school buildings following an asbestos removal (14). Zt is not uncommon to find the ambient airborne concentrations exceeding those inside office or school buildings. The current EPA criteria for clearance of a school building following an asbestos removal project 6 is .02 fibers/cc by transmission electron microscopy for total fibers. At that level the EPA considers the building cleared for occupancy. - Doll & Peto (25), Weill Hughes (26), and Hughes fi Weill (27) all have made contemporary predictions of the risk of environmental exposures at these levels. Doll and Peto predict one excess death from environmental exposure in a year in the United Kingdom. Such a low level of risk at the known environmental levels in the United Kingdom and the United States would account for the fact that millions of people so exposed do not demonstrate asbestos- related diseases; suggesting a lower no-effect level. 3. VOLUME OP ASBESTOS USED IN SHIPYARDS: It is important to sake a_contrast between the discussion of environmental exposures and the amount of asbestos used in a Naval Shipyard in the 1940's during the World War II years. The PleischerDrinker report on Naval shipyards published in 1946 shows that in those small Industrial communities 200,000 to 200,000 pounds of asbestos products would be used each month in ship construction (18). The report made no mention of the volume of asbestos that needed to be removed prior to overhaul or renovation. The amount of material alone sets the conditions for high levels of exposure to workers handling the asbestos under .-these-conditions. About-90k of the products used were amoslte blankets or pads, loose areosite, magnesia block insulation, and asbestos cements. 7 .1* All of these material* were loose, easily broken or crumbled, and handled directly by workers. The potential for high level exposure, especially peaks. Is apparent. Few effective control measures were In place at that time largely because the real risk from high level exposures over long periods of time-were not realized because of the extreme latency period. 4. EXPOSURES OF THE CONSTRUCTION AND SHIPYARD TRADES: There are several studies that attempted to define the occupational exposures to workers in the construction and shipyard trades in the 1960's. They constitute a cross section of the American experience at controlling high level occupational exposures where they were occurring In Industry. In 1970, Mangold, Beckett, and Bessmer (3,4) published a report on exposures to asbestos at Puget Sound Naval Shipyard showing that 21k of asbestos workers showed pulmonary abnormalities. They concluded that the TLV of 5 MPPCF was too high, that peaks were Important, and that changes of work practices were required. The publication contains the levels of exposures recorded for the workers activities. In 1968, W.C. Cooper and L. Baltzer (19) published a similar study of construction workers In the San Francisco Bay area. About 25k of the construction workers handling asbestos products and receiving high level exposures showed x-ray changes of'the lungs. They concluded that the TLV was too high and needed to be reduced. The types of products and 8 A the levels of occupational exposure for the construction workers was recorded. In 1971, Gaensler (20} published a study of exposures and medical findings in a private shipyard on the East coast. He concluded that exposures were too high and that the TLV should be reduced. A comparison of the asbestos exposures by job are contained in the report. These three studies show that the use of large volumes of asbestos with corresponding high levels of exposure were commonplace among those required to handle or remove It. Such substantial levels of exposure are those that account for the asbestos-related diseases following long latency periods. The concentrations are many orders of magnitude above background levels, or environmental exposures. 5. CURRENT ALLOWABLE LEVELS OP EXPOSURE: The American Conference of Governmental Industrial Hygienists (ACGIH) adopted a Threshold Limit Value (TLV) for asbestos in 1946 of 5 millions of particles per cubic foot of air sampled for an 8 hour time-weighted average workday (TWA). It remained in effect until 1969, when it was reduced to 2 KPPCF or 12 flbers/cc. Currently, separate TLV's are published for each type of asbestos used commercially; A. Chrysotile: 2 fibers/cc, 8 hr TWA B. Amosite: .5 fibers/cc, 8 hr TWA _ C. Crocidolite: .2 fibers/cc, 8 hr TWA D. Other: 2 fibers/cc, 8 hr TWA 9 The current OSHA Federal standard for occupational exposure to asbestos is .2 flbers/cc for all forms of asbestos used commercially. It aakes no distinction between the types of asbestos. The regulation specifies the use of a special technique of air sampling and laboratory analysis by phase contrast alcroscopy at 400 X aagnification (11). The SPA now regulates school clearance following an asbestos removal project to .01.flbers/cc as determined by transmission electron mlcroseopy, a precise aethod that aeasures all asbestos fibers present (14). S. It is apparent that the ACGIH recommendations do not agree with the OSHA permissible exposure limit. The EPA clearance- level Is aimed at public policy for schools where asbestos Is managed, or removed. 6. CONTINUING EVALUATIONS: Following control programs in the 1960's and 1970's and more recently those mandated by Federal or State regulations, the overall occupational exposure levels to workers has dropped markedly. Investigators have now turned to other sources of asbestos used in industry to determine the contribution to the overall exposure, if any. .- - "" In the 1960's the major goal was to reduce the 10 high level exposures occurring from highly friable asbestos materials used in large volume in construction and in shipyards. The small volume products and those that were encapsulated were not considered because of the small contribution to the overall exposure pattern (3,4). And. because tests revealed that the low emissions were obscured by the high background levels from other highly friable products (3,4,19,20). Most of the data in the earlier reports evaluate processes which Include the influence of all sources of asbestos that may be present. Zt is difficult to differentiate the contributions of the various types of asbestos products which were being used at the same time, or in hear proximity to each other. 7. U.S. NAVY GASKET REPORT: In 1978, the U.S. Department of the Navy (21), as part of a continuing evaluation program, set about evaluating the asbestos exposures to workers from the storage, handling, and processing gaskets of all kinds in Naval shipyards. The evaluation is important because there are only a few such publications that identify and estimate the occupational exposure to gasket materials in shipyards, the report concludes that even the simplest of general housekeeping controls or work practices are sufficient to maintain occupational exposures at acceptable levels. In fact, most of the exposures were found to be less than .1 flber/cc 11 for an 6 hour TWA, a level at which medical examinations are not required according to the current Federal standard for asbestos. The 1978 U.S. Navy report did achieve the intended purpose to determine the exposure to any and all asbestos in the breathing zone of workers but does not determine the actual ccntrlfcwtlan from the gaskets alone. The breathing zone air samples were collected for various forms of gasket processing in some work areas under uncontrolled conditions and in the presence of contamination from other asbestos products. The results are actually the contribution from the gaskets, background levels, and contamination from other asbestos products. They do not reflect the aetual contribution from the gaskets. Because the airborne concentrations were extremely low, often .01 fibers/cc or less, the potential for contamination Is certrJn and cause a major contribution to the reported values for gasket processing. Many of the reported values reflect the actual exposure time; not an 8 hour time-weighted average. The 8. hour TWA measurement or calculation is necessary to be able to compare the values to the current Federal standard. Short term peak exposures measured in this way will nearly always be greater than the 8 hr TWA, often by several orders of magnitude. While the 1978 U.S. Navy report achieved the intent there are several objections in the use of the 12 J* data to reflect the actual contribution froa gaskets alone. They are; A. Short tern peak exposures are reported that cannot be directly compared to the 8 hour TWA of the Federal standards. B. No atteapt was Bade to control or factor the contributions of contamination froa the results. The contamination levels may even have exceeded the actual contribution from the gaskets processed. C. The data was Intended to determine the overall peak exposures froa unit operations that included all asbestos contributions. -' The small contributions from gaskets are confounded or-obscured by high background contamination levels where the gaskets were processed, contaminated clothing, and atmospheric pollution. 8. VERIFICATION OF THE 1978 U.S. NAVY STUDY: Because of the objections offered above, the U.S. Navy report could not be used with accuracy to reflect the actual contribution of gaskets alone. In 1982, the Oarlock, Inc. commissioned C.A. Mangold (22) to repeat the U.S. Navy Investigation on gaskets as nearly as possible and to take into account the effects of contamination in order to make estimates of the actual contribution of gaskets to the occupational exposure of a worker handling or 13 J* processing them. In addition, the data was to reflect the 8 hour time-weighted average work day for dlreet comparison to the existing Federal standards for asbestos. Samples of the ambient air were collected in various cities to show the apparent level of natural and aanaade asbestos fiber pollution. The effects of contaminated . clothing that, a worker may wear were evaluated to determine the contributions. All sources of contribution were considered to control or faetor those background levels that were not part of the contributions from the processing of the gaskets. After the background levels were measured or controlled, the data showed that hardpressed or encapsulated Garlock, Inc. gasket products released insignificant levels into the breathing zone of workers processing gaskets in the same manner as conducted in Naval shipyards. The actual contribution for the processing of gaskets averaged .02 fibers/cc for an S hour TWA when the effects of contamination from other sources or asbestos products were controlled. The peak background levels of ambient air in industrial areas, or in cities on warm summer days may reach these levels. This verification of the O.S. Navy report revealed that when the contamination was factored or controlled the values for the actual contribution from gaskets were about 50k of those reported by the O.S. Navy. The study conducted by Mangold (23) more appropriately 14 reflect* the actual contribution fron handling or processing encapsulated gasket for an 6 hour tine-weighted average-work day. The overall average of .02. fibers/cc is l/10th of the current Federal standard for occupational exposure to asbestos fibers In air. 9. THE DILEMMA-: The verification of the 1978 D.S. Kavy report shows that hardpressed or encapsulated gaskets actually contribute negligible amounts of asbestos when handled or processed as in Industry or in shipyard. Negligible exposures present a negligible risk. The risk is in the sane aagnitude as some environmental exposures to the population at large. * However, additional measurements under highly controlled conditions are needed because: A. Some workaen describe specific aethods of handling, processing or rescuing gaskets fron naehlnery or piping that were not evaluated in the 1978 U.S. Navy report or the subsequent verification. Soae are not standard operating practices expected of workaen experienced in the handling, processing or reaoval of encapsulated gaskets froa machinery or piping. B. The 1978 U.S. Navy report and the 1982 verification contains the effects of_ levels of., contamination that-are in the same range as the expected actual contribution of airborne asbestos fibers froa the gasket alone. Therefore, 15 4* the results will be skewed upward by that contaalnatlon contribution. Better definition Is needed where the effects of other asbestos products do not Interfere with the tests. ,C. Ambient concentrations of ehrysotlle asbestos fibers that occur naturally from soil and water, and froa manmade products add some contribution to the measurements of the emission from'gaskets. The contributions can be substantial and in the same range as the expected aetual emission from the gaskets being handled, processed or removed. D. Kew analytical methods that were not available or practical for the U.S. Havy report In 1978 or the verification in 1982, are now readily available and within S. economic practically. These methods can provide a more precise examination of the actual release of fibers froa encapsulated gaskets. . E. The new analytical methods have a much.lower limit of detection that those used in the 1978 and 1962 reports. The methods now available can not only determine the total number of fibers present, but determine the types of fibers they are. This is valuable because the chryaotlle asbestos is used in encapsulated gaskets. F. The new analytical methods can make a direct comparison to the older Phase Contrast Microscopy (PCM) method specified in the Federal standard through the use of Scanning Transmission Electron Microscopy (STEM). It can verify the PCM method which is easily influenced by other non-asbestos fibers, if they are present. 16 G. A better definition of by-stander exposure was needed;, that is, the levels of exposure of a worker 5 or 10 feet away froa another worker Baking, Installing, or removing encapsulated gaskets. 10. EXPERIMENTAL DESIGN: . Although the 1978 U.S. Navy report and the 1982 verification show that only negligible aaounts of asbestos fibers are released froa the handling or processing of gaskets, additional measurements are needed to utilize the. new analytical methods, to better control the effects of ambient or manmade contamination, and to determine the actual contributions from the gaskets handled in the ways described by some workmen. And, the by-stander exposures from those selected processes. A clean room condition was needed for the testing in order to accurately aeasure the low level release of chrysotile asbestos fibers from the encapsulated gasket materials processed or removed from flanges. Since the . emissions were expected to be near the limit of detection of phase contrast microscopy methods used, special precautions were taken to control potential contamination. A new metal building was leased in Rent, Washington 17 where electron microscopy samples showed that the amount of natural ambient asbestos was .002 fibers/cc or less for all sizes of fibers. The new building was selected to ensure that accumulation of dust, or previous asbestos insulation contamination was not present. inside the building, an enclosure of polyethylene plastic was constructed that measured 20 feet by 20 feet and 10 feet high, or 4000 cubic feet. This represents a small compartment or room where such work may be done in industry or aboard ship and that may be oeeupled by a by stander. The ceiling and floor was covered with polyethylene plastic and all the edges were sealed. The only entry was a t specially designed flap door that would remain sealed during testing. A clean work bench was placed in the center of the enclosure. The gaskets were processed on the bench according to the descriptions given by some workmen. Sample locations were assembled on the points of the compass at head height Inside the room. The sample stations were located 5 and 10 feet away from the work bench in the center of the room. The sample cassettes for analysis by phase contrast microscopy and scanning electron microscopy were placed at the sample stations. Air was drawn through the special filters in the cassettes by electrically operated high volume air samplers. The volumes of air were seasured by recording the flow rates with a class A rotometer and recording the amount of time the samples were collected. Nine IB PCM and 8 STEM samples were collected for each test. One PCM was worn by the operator at the work bench to record the breathing zone exposure. The other saaple stations provided a preponderance of data and simulated by-etander exposures at 5 and 10 feet away from the gasket processing. - Samples of gasket material containing chrysotlle asbestos were- obtained from the manufacturer for processing. And, piping and valves were obtained from a U.S. Naval vessel, the DSN Gypsy (ARSD-1) which was scrapped In Portland, Oregon. She wes built in 1944, served in the Pacific Theatre during World War II, and was decommissioned in the 1950's. Some of the flanges had never been opened since the vessel was built. All of the residual asbestos Insulation on the outside of the piping was removed to'prevent contamination when the gaskets were removed from the flanges. Plastic impregnated protective clothing (TYVEC) was worn by the operator to control the potential release of non-asbestos fibers from street clothing, and dust from shoes. - The tests were conducted over an 8 hour time-weighted work day. This is necessary to develop data that can be directly compared to the Federal standard for occupational exposure to asbestos. Zt is inappropriate to attempt to compare peak exposures to the Federal standard. Following the tests, the sample cassettes were removed and delivered to ESSTEK, a highly qualified asbestos 19 analytical laboratory capable of conducting phase contrast microscopy (PCM) according to Appendix A, of the Federal asbestos' standard, and transmission electron microscopy (TEM)* Special arrangements were made to directly compare the results by PCM with that obtained by TEM. The PCM analysis is subject to influence by non-asbestos fibers that may be present. But, the TEM method is highly specific, determines all asbestos fibers present, identifies the type of fiber present, and has a very low limit of detection about .002 structures/cc (approximately equal to fibers/ec). Arrangement were made to have at least 75ft of the PCM samples blind counted. This means at least two qualified asbestos counters would make a determination without knowing the result of the other. The results are then compared. This minimizes-the potential for counting errors. . The PCM and the TEM samples collected at each sample location at the same time and filtering about the same volume of air, were compared as duplicates. This provides two separate determinations with highly specific methods at the same location and gives a high degree of confidence that each determination is comparative. The results and conclusions for the tests conducted are found in paragraphs 12 and 13. 20 22. REFERENCES: 2.'. A. Churg and M. Warnock, "Asbestos Fibers In the Genera2 Population", Aa. Rev. Reap. Disease, Vo2 122 (2900) '2. W.T. Karr, "Asbestos Exposure During Naval Vessel Overhaul, Aa. "Ind. Hyg. J. 25:264 (May-June 1964) 3. C.A. Mangold, R.R. Beckett, D.J. Bessaer, "Asbestos Exposure and Pulmonary X-Ray Changes to Pipe Coverers and Insulators at Puget Sound Naval Shipyard," PSNS, Dept, of Navy, Breaerton, HA. (August 1968} 4. C.A. Mangold, R.R. Beckett, D. J. Bessaer, "Asbestos ' Exposure and Control-Puget Sound Naval Shipyard," D.S. Dept, of Navy, (May 1970) 5. l.J. Selikoff, J. Churg, E.C. Hansons, "Asbestos Exposure and Neoplasia", JAMA 188:22 (1964) . 6. l.J. Selikoff, J. Churg, E.C. Hanaons, "Relation Between Exposure to As'.'.4*stos and Mesothelioma", N. Eng. J. Med. 272:560-565 (1965) . 7. l.J. Selikoff, M.D., "Disability Compensation for Asbestos-Associated Disease in the United States", Env. Sci. Lab, Mt. Sinai .Hospital, City Univ., N.Y. (Report to U.S. 21 Dept of Labor - (June 2982) 8. J.E. Craighead, B.I. Mossman, "The Pathogenesis of Asbestos-Associated Diseases", N. Eng. J. Med., 306 (June 17, 1982) 9. M.R. Beeklake, "Exposure to Asbestos and Busan Disease", N. Eng. J. Med., 306, (June 17, 2982) 20. W.J. Nicholson, A. M. Banger, I.J. Selikoff, "Epidemiological Evidence on Asbestos", Proceedings of a Workshop on Asbestos Definitions and Measurement Methods. (July 1977) Gaithersburg, MD, U.S. Dept. Commerce Pub. # 506 (Nov 1978) ' 12. Federal Asbestos Standard: 29 CFR 1910.1001 and 2926.58; Occupational Exposure to Asbestos, Tremollte, Ar.whophyllite, and Actinolite, Final Rules, (June 20, 1986) 12. Dr. Andrew Churg, "Chrysotile, Tremollte and Malignant Mesothelioma in Man", Chest 93(3): 622:628 (1988) 13. A. Churg and L. De Paoli, "Clearance of Chrysotile Asbestos from Human Lung", Experimental Lung Research, 14(5): 567-574 (1988) . -- 14. Environmental Protection Agency: 40 CFR, Part 763, 22 A Asbestos-Confining Materials in Schools; Pinal Pule and Notice, (Oct 30, 1987) 15. R. Doll and J. Peto, "Asbestos; Effects on Health of Exposure to Asbestos", London, Her Majesty's Stationery Office, (1986) 16. H. Weill and J. Hughes, "Asbestos as a Public Health Risk: Disease and Policy", Ann Rev Pub Hlth, 7, (1986) 17. J. Hughes and B. Weill, " Asbestos ExposureQuantitative Assessment of Rlslc", Am Rev Resp Dis (1986) 18. W.E. Fleischer, F.J. Vlles, R.L. Cade, and Phillip Drinker, -"A Health Survey of Pipe Covering Operations in Constructing Naval Vessels", J. Znd. Hyg. ft Tox. 26:9 (Jan 1946) 19. J.L. Baltzer and W. Clark Cooper,M.D.," The Work Environment of Insulating Workers, Am. Znd. Hyg. Assoc., 29:222 (May-Jun 1968) 20. R.L.H. Murphy, Jr.M.D., B. Ferris, W. Burgess, J. Worcester, E.A. Gaensler, M.D., "Effects of Low Concentrations of Asbes.tos: .Clinical, Environmental-,Radiological, and Epidemiologic Observations in Shipyard Pipe Coverers and Controls", N. Eng. J. Med., 23:285, 23 (December 2971) 21. '. L.R. Liukonen, K.R. Still, R.R. Beckett, "Asbestos Exposure from Casket Operations", D.S. Dept, of Navy, Bremerton, Washington ( May 1978) 22. C.A. Mangold, "The Actual Contribution of Garlock Asbestos Casket Materials to the Occupational Exposure of Asbestos Workers", October 1982, Bellevue, Washington. 24 J* 13 t 14 RESULTS AND CONCLUSIONS: Asbestos containing gasket stock can be cut to shapes with a pair of Industrial shears. The stock is first cut to a general size for the flange face or aachinery part, then shaped to the desired size with the shears. The bolt holes are customer.iiy cut with a hollow punch. New Garlock Inc. Style 900/773S , containing about 70k chrysotile and ordinarily used for flange faces and machinery parts, was selected for cutting to gasket size with a pair of industrial shears, the bolt holes were cut with a hollow punch as customarily done in the preparation of gaskets. One gasket was cut each hour over 8 hours to simulate the actions of a workman preparing gaskets as needed throughout a work day. and to establish the 8 hour time-weighted average for comparison to the Federal standard permissible exposure limit of .2 fibers/cc. These two tools may be used by some workmen to prepare gaskets. The conduct of the operation in a clean room with low background and low ambient levels in the air would establish the exposures to any by-stander near the operator cutting gasket materials in this way. The attached data sheets show that; 1. The electron microscopy methods for total chrysotile in samples collected at each of 8 sample stations averaged .006 structures/cc or less. The struct\ires/cc are approximately equal to fibers/cc. This method determined all of the chrysotile fibers regardless of size. There is no 25 total fiber standard. 2. The electron microscopy analyses of the samples for all fibers greater than 5 micrometers in length and .25 micrometers in diameter .is a direct method of comparison to the phase contrast microscopy method specified in the Federal standard. In this way the phase contrast microscopy results can be verified. The results averaged .002 fibers/cc or less. 3. The phase contrast microscopy results for the 8 sample stations averaged .004 or less. This would represent the exposure pattern of a by-stander in the room with the operator. The exposure pattern of the operator was .005 fibers/cc. All of the results represent an 8 hour time-weighted ' average for direct comparison to the Federal standard of .2 fibers/cc, >5 urn in length. The exposure pattern is a fraction of the Federal standard as expected. Hard pressed, encapsulated asbestos gaskets release insignificant amounts of chrysotile asbestos under such conditions of use. - The results show that when gasket stock is cut with a shears and bolt holes cut with a hollow punch in a clean room where contamination or high ambient levels cannot interfere, the actual contribution from the gasket processing is negligible in terms of the permissible exposure limit of .2 fibers/cc. The precise"electron-microscopy methods'verify and corroborate the results. 26 I ow* LOCATION OF SAMPLE STATIONS IN THE ASBESTOS FIBER FREE ENCLOSURE IAA*Y PUP I0M 0 5 vu 5N bENCH 5s, *5z ia$* Enclosure Height * 10' IOL SET III "Casket Cutting With Hand Shears" TRANSMISSION ELECTRON MICROSCOPY AIR SAMPLE ANALYSIS RESULTS CLIENT: Carl A. Mangold, CIH PROJECT: Carlock Research REPORT I: 812031 PACE: 3 of 13 CLIENT SAMPLE ID ESSTEK ID iCONCENTRATION CHRYSOTILE ALL SIZES STRUCTURE SIZE CHRYSOTILE COUNTED LENCTH >5.0 UB STRUCTURES IS/cc) DIAMETER >.25 UB CONCENTRATION LENCTH >5.0 DIAMETER >.25 S/CC T5N-9 812031 T5E-10 812032 T5S-11 . 812033 T5W-12 812034 T10N-13 812035 T10E-14 812036 T10S-15 812037 TlON-16 812038 LAB BLANK 2 0.005 3 0.007 6 0.014 NSD BLD 4 0.009 NSD BLD 2 0.005 NSD BLD NSD X r 'c0(* 1 '2 2 NSD NSD NSD 1 NSD 0.002 0.005 -0.005 0.000 0.000 0.000 0.002 0.000 X- * Analytical Sensitivity 0.002 S/ec NSD - No Structures Detected BLD * Belov Level of Detection S/cc - Structures per ce fibers per cc 3LD TO ,007. Environmental Safety Systems, Inc. Gateway Corporate Park, lldg. S 12822 Cateway Drive Seattle, Washington 91168 (206) 243-6573 AIR SAMPLE ANALYSIS REPORT C2JB7T: Carl A. Mangold, C.I.K, - 3033 170th Place SE Bellevue, VIA 98008 PROJECT! Garlock Research - Set II Casket Cutting with Band Shears REPORT || 50-128110 REPCRT DttEt 12-09-88 FAS 1 Of 2 DAIS RECEIVE)t 12-02-88 F0 ft Nxe Given rr.TTVP SAMPLE ID ESS ID SAMPLE SAMPLE DATE VCL (L) /100FIBER FXHD BLAIR CNT FIBERS BKGRK) COWT COUNT FLOS pro cc * MAT ** PSN-9 128110 11-25-88 1680 14.0 100 P5E-10 128111 11-25-88 1680 8.0. 100 P5S-11 128112 11-25-88 1680 15.0 100 PSW-12 ' 128113 11-25-88 1610 11.0 100 PION-13 128114 11-25-88 1680 23.0 100 P10E-14 128115 11-25-88 1680 14.0 100 P10S-15 128116 11-25-88 1540 9.0 "100 P10W-16 128117 11-25-88 1680 16.0 100 4.0 100pp-2^pFrsohA l') 128118 11-25-88 960 P-BLX-2 128119 11-25-88 0 1.0 100 SAMPLE LOCATIONS: Sample #128110 was taken north 5ft at statj.cn. Sasple #128111 was taken east 5ft at jacple station. Sanple #128112 was taken south 5ft at sample station. Sample #128113 was taken west 5ft at sample station. __________ Bulk Sampling Air Monitoring Analysis Asbestos Abatement Equipment & Supplies 1.00 0.004 L 1.00 < 0.003 M 1.00 0.004 M 1.00 0.003 M 1.00 0.006 M 1.00 0.004 M 1.00 < 0.003 M 1.00 0.004 M 1.00 < 0.005 ) L N/A BLANK X - ,co4f * MR SAMPLE ANALYSIS REPORT CLIENT: Girl A. Mangold, C.X.H. PROJECT: Gaxlock Research - Set II SAMPLE LOCATIONS' ^continued) t REPORT I: 50-128110 PAGE 2 Of 2 Sanple #128114 was taken north 10ft at sanple station. Sanple #128115 was taken east 10ft at sample station. Sanple #128116 was taken south 10ft at sanple statim. Sanple #128117 was taken west 10ft at sanple station. Sanple #128118 was a personal sanple in breathing zone of operator. Sanple #128118 was submitted as a field blank. The sanples analyzed in this report were provided by third parties not subject to control by Bivircnmental Safety Systems, Inc. (ESS) or its affiliates. Consequently, tte results presented represent microscopic examinations in ESS laboratory facilities and ESS no representation as to sasple collection techniques or procedures. Analysis was performed using phase contrast microscopy under the guidelines of NXQSH method #740Q-A. * A mininun of ten fibers per 100 fields is needed for reliable quantification. Sanples with less chan 10 fibers per 100 fields are reported -as less than (<) the quantification limit. _ . ** Amounts of ncn-fibrous material are determined using charts for estimating canpcsition fran the Journal of Sedimentary Petrology (v. 25, pp. 228-234, 1855). Amounts reported reflect nan-fibrous material density an sanple filter only. Legend: T * Trace (less than 1%), VL Very Low (2-5%), L * Low (5-15%), K Moderate (15-25%), H * High (25-40%), VH * Very High (greater than 40%). 2 Microscope Field Area 0.00785 am " Analyst (s) - TAP ESposed Filter Area 385.0 am2 Reviewed by: