Document 6BOY0naa3DR88qpVy0xyGKDnd

THE ACTUAL CORTRIBUTIOR or AIRBORJIE ASBESTOS mw JO THE OCCUPATION*^ EXPOSURE OF BT-STARDERS DOEIBG . SELECTED PROCESSING or PCAPSULATED ASBESTOS RMwn i k CUTTING GASKETS WITH A CIRCULAR CUTTER CARL A. MARGOLD, CIE EEVISOaKEETAL CORTROL SCIERCES. IRC. BELLEVUE, KASHIRGTOR JARUART 1989 s ABSTRACT Asbestos containing gaskets are customarily cut with a circular cutter. The asbestos stock is placed upon a flat surface then the cutting device Is placed upon the "Stock and rotated. A sharp blade in the head of the cutter cuts the gasket according to the size desired. Both inside and outside cuts can be may easily in a few minutes. The flange holes are cut with a special hollow punch and a heavy mallet. New Oarlock Inc. gasket stock # 900/7735, containing about 70* chrysotile, which is customarily used for pipe flanges and machinery was cut using the circular flange gasket cutter. One gasket was cut each hour to simulate a worker making gaskets as needed throughout a work day. The air samplers placed on the operator and at 5 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. The results showed that; . 1. The electron microscopy analyses for total libers averaged .01 structures/cc, or less {structures/cc * fibers/cc). 2. The electron microscopy analyses for fibers i greater than 5 micrometers in length as a comparison to the phase contrast microscopy method averaged .002 fibers/'ce or less. The electron microscopy is precise and determined that only chrysotlle was present. J. The phase contrast microscopy methods of analyses revealed that the average concentration for fibers greater than 5 micrometers in length was .003 fibers/cc or less. This is the method specified in the Federal standard for asbestos. 4. The personal sample averaged .005 fibers/cc by \ phase contrast microscopy. The 8 hour time-weighted averages to the operator and a bystander in the enclosure are a fraction of the Federal standard of .2 fibers/cc. TABLE or cortmt. ABSTRACT TABLE OP CONTENTS BACKGROUND ENVIRONMENTAL EXPOSURES VOLUME Or ASBESTOS USED INSHIPYARDS ' EXPOSURES OP THE CONSTRUCTION AND SHIPYARD TRADES CURRENT ALLOWABLE LEVELS OPEXPOSURE CONTINUING EVALUATIONS U.S. NAVY GASKET REPORT VERIFICATION OP THE NAVYGASKET REPORT THE-DILEMMA EXPERIMENTAL DESIGN REFERENCES RESULTS AND CONCLUSIONS 1 1 2 8 7 8 9 10 11 13 15 17 21 24 rt 1 1. BACKGROUND: Asbestos Is one of the aost plentiful, useful, and cheap Industrial minerals. Because of Its high thermal stability and resistance to corrosion It appears In more 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 oceurs 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. Zn 1980, Dr. Churg (1) determined that aost city-dwellers retain a considerable amount of asbestos in their lunge 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: aabestosis, 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 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 eoaaereially. Few, If any, controls were followed so that time and intensity factors led to dose levels that precipitated various degrees of asbestosls. This continued until the 196a'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 means of voluntary controls and legislations that led to the first Federal standards in 1972. Since that time the permissible exposure levels of asbestos have been reduced through the regulatory processes in the United States. 2n 1964, Karr (2) concluded that asbestos-related disease was an Important problem among Insulators working in Naval shipyards. His 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 & Bessmer (3,4). Most of the attention was directed at the products and the r ' 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 i* was still too high at 5 Billions of particles per cubic foot (MPPCP), equivalent to about SO fibers per cubic centimeter, and that intermittent peak exposures were far more important that previously recognized. Both conclusions have been corroborated by more recent literature. About 1964, Selikoff .(9,6) and others reported the . association of exposure to asbestos with asbestos-related \ cancers and the effects of smoking. Zn 1978, Dr. Selikoff (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. (8), 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 asbestosis, 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 MS" shaped curve, so often found where a lower no-effect level is reached. Otherwise, Billions of Americans receiving dally exposures to asbestos froa 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. Zt 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 aade the assumption that all forms of asbestos, namely Chrysotile, Amoslte, and Croeldolite, and more 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 is substantial. Asbestos, mainly ChrysotUe, 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 aay 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 Bast and West coast and along the border with Canada, Billions of Americans receive dally and substantial exposures to asbestos froa 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 froa sanaade 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 fibers/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). It 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 reaoval project 6 is .02 tibers/cc by transmission electron microscopy for total fibers. At that level the EPA considers the building cleared for occupancy. Doll k Peto (15), Weill k Hughes (16}, and Hughes k Weill (17) all have made contemporary prediction* of the risk'.of environmental exposures at these levels. Doll and Peto predict .one excess death froa environmental exposure ' in a year in the United Kingdom. Such m 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 asbestosrelated diseases; suggesting a lower no-effect level. 3. VOLUME OF ASBESTOS USED IN SHIPYARDS: It is Important to' aake a contrast between the discussion of environmental exposure's and the amount of asbestos used in a Naval Shipyard in the 1940's during the World War II years. The PlelscherDrlnker report on Naval shipyards published in 1946 shows that in those small industrial communities 100,000 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 aaterial alone f sets the conditions for high levels of exposure to workers handling the asbestos under these conditions. About 90* of the products-used were ajfoaite blankets or pads, loose amoslte. magnesia block insulation, and asbestos cements. 7 y* All of these materials 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 extreae latency period. 4. EXPOSURES OF THE CONSTRUCTION AND SHIPYARD TRADES: There are several studies that atteapted to define the occupational exposures to workers In the construction and shipyard trades In the 1960's. They constitute a cross section of the Aaerlcan experience at controlling high level occupational exposures where they were occurring In Industry. In 1970, Mangold, Beckett, and Bessaer (3,4) published a report on exposures to asbestos at Puget Sound Naval Shipyard showing that 21k of asbestos workers showed pulaonary abnormalities. They concluded that the TLV of S 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 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 voluaes 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 OF EXPOSURE: The American Conference of Governmental Industrial Hygienists (ACGIH) adopted a Threshold Limit Value (TLV) ' for asbestos in 1946 of 5 millions of partleles 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 fibers/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 flbers/cc, 8 hr TWA 9 The current OSHA Federal standard for occupational exposure to asbestos is .2 fibers/cc for all forms of asbestos used commercially. Zt makes 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 microscopy at 400 X magnification (11). The EPA now regulates school clearance following an asbestos removal project to .01 fibers/cc as determined by transmission electron microscopy, a precise method that measures all asbestos fibers present (14). Zt is apparent that the ACGZK recommendations do not agree with the OSKA permissible-exposure limit. The EPA clearance level is aimed at public policy fo- 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 how 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 aaterials used in large volume in construction and lh shipyards. The snail volume products and those that were encapsulated were not considered because of the snail contribution to the overall exposure pattern (3,4). Andbecause tests revealed that the low enissions 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 nay be present. Zt is difficult to differentiate the contributions of the various types of asbestos products which were being used at the sane tine, or in near proxlnlty to each other. 7. U.S. NAVY GASKET REPORT: Zn 1976, the O.S. Department of the Navy (21), as part of a continuing evaluation progran, set about evaluating the asbestos exposures to workers from the storage, handling, and processing gaskets of all kinds in Naval shipyards. The evaluation is laportant 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. Zn fact, most of the exposures were found to be less than .1 fiber/cc 11 for an 8 hour TWA, a level at which aedical exaainations are not required according to the current Federal standard for asbestos. . . The 1978 D.S. Navy report did achieve the intended purpose to deteraine the exposure to any and all asbestos in the breathing zone of workers but does not deteraine . the actual contribution froa the gaskets alone. The breathing zone air saaples were collected for various foras of gasket processing in soae work areas under uncontrolled conditions and in the presence of contaaination froa other asbestos products. The results are actually the contribution froa the gaskets, background levels, and contaaination froa other asbestos products. They do not reflect the actual contribution froa the gaskets. Because the airborne concentrations were extremely low, often .01 fibers/cc or less, the potential for contaaination la certain and cause a major contribution to the reported values for gasket processing. Many of the reported values reflect the actual exposure tine; not an 8 hour time-weighted average. The 8 hour TWA aeasurement or calculation is necessary to be able to coapare 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 data to reflect the actual contribution from gaskets alone. They are; A. Short term peak exposures are reported that cannot be directly compared to the 8 hour TWA of the Federal standards. ,,B. No attempt was made to control or factor the contributions of contamination from 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 from 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. Zn 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 actualcontribution of gaskets to the occupational exposure of a worker handling or 13 processing them. In addition, the data was to reflect the 6 hour time-weighted average work day for direct 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 manmade asbrttos 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 factor 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 bardpressed or encapsulated Oarlock, Znc. 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 flbers/cc far an hour TMA 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 wars 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 U.S. Navy. The study conducted by Mangold (23) more appropriately 14 J* reflect* the actual contribution from handling or processing encapsulated gasket for an 8 hour time-weighted average work day. The overall average of .02 flbers/cc Is 1/lOth of the current Federal standard for occupational exposure to asbestos fibers In air. 9. THE DILEMMA: ' The verification of the 1978 U.S. Navy 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 case magnitude as soae environmental exposures to the population at large. However, additional measurements under highly controlled conditions are needed because; A. Some workmen describe specific methods of handling, processing or removing gaskets from machinery 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 workmen experienced in the handling, processing or removal of encapsulated gaskets from machinery or piping. .V 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 from the gasket alone. Therefore, 15 the results will be skewed upward by that contamination contribution. Better definition is needed where the effects of other asbestos products do not interfere with the tests. C. Ambient concentrations of chrysotile asbestos fibers that oceur 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 actual emission from the gaskets being handled, processed or removed. O. New analytical methods that were not available or practical for the U.S. Navy report in 1978 or the verification in 1982. are now readily available and within 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 1982 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' chrysotile asbestos -is used in encapsulated gaskets. P. 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). Zt can verify the PCM method-which' is easily influenced by'other non-asbestos fibers, if they are present. 16 A G. A better definition of by-stander exposure was needed, that is, the levels of exposure of a worker 5 or 10 feet away from 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 from 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 measure the low level release of ehrysotile 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 say be occupied by a by stander. The celling and floor was covered with polyethylene plastic and all the edges were sealed. The only entry was a 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 measured by recording the flow rates wirth a" class A rotometer-and recording the amount of time the samples were collected. Nine 18 PCM nd 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 sample stations provided a preponderance of data and simulated bystander exposures at 5 and 10 feet away from the gasket processing. -Samples of gaskst material containing chrysotile j asbestos were-obtalned from the manufacturer for processing. And, piping and valves were obtained from a O.S. Naval vessel, the USN Gypsy (ARSD-1) which was scrapped in Portland, Oregon. She was 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 (TYVBC) 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. It is inappropriate to attempt to compare peak exposures to the Federal standard. Following the tests, the sample cassettes were removed and delivered to SSSTEK, 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 w - t that say 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/ce (approximately equal to fibers/ec). Arrangement were made to have at least 75* 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 11. REFERENCES: !'. A. Churg and M. Warnock, "Asbestos Fiber* in the General Population", Am. Rev. Reap. Disease, Vol 122 (1980) -2. W.T. Harr, "Asbestos Exposure During Naval Vessel Overhaul, Am.-Znd. Hyg. J. 25:264 (May-Junt 1964) 3. C.A. Mangold, R.R. Beckett, D.J. Bessmer, "Asbestos Exposure and Pulmonary X-Ray Changes to Pipe Coverers and Insulators at Puget Sound Naval Shipyard," PSNS, Dept, of Navy, Bremerton, WA. (August 1966) 4. C.A. Mangold, R.R. Beckett, D. J. Bessmer, "Asbestos Exposure and Control-Puget Sound Naval Shipyard," U.S. Dept, of Navy, (May 1970) 5. Z.J. Selikoff, J. Churg, E.C. Hammons, "Asbestos Exposure and Neoplasia", JAMA 188:22 (1964) 6. X.J. Selikoff, J. Churg, E.C. Hammons, "Relation Between Exposure to Asbestos and Mesothelioma", N. Eng. J. Med. 272:660-565 (1965) ,, 7. Z.J. Selikoff, M.D., "Disability Compensation for Asbestos-Associated Disease' in the United States", Env. Scl. Lab, M'-. Sinai Hospital, City Univ., H.Y. (Report to U.S. 21 Dept of Labor - (June 1982) 8.- J.E. Craighead, fl.T. Mossman, "The Pathogenesis of Asbestos-Asaoeiated Diseases", H. Eng. J. Med., 306 (June 17, 1982} 9. M.R. Becklake, "Exposure to Asbestos and Huaan Disease", N. Eng. J. Med., 306, (June 17,-1982} 10. w.J. Kleholson, A. M. Ranger, Z.J. Sellkoff, "Epideaiological Evidence on Asbestos", Proceedings of a Workshop on Asbestos Definitions and Measurement Methods. (July 1977} Gaithersburg, MD, U.S. Dept. Coaaerce Pub. 506 (Mov 1978) 11. Federal Asbestos Standard: 29 CFR 1910.1001 and 1926.58; Occupational Exposure to Asbestos, Treaollte, Anthophylllte, and Actinolite, Final Rules, (June 20, 1986) 12. Dr. Andrew Churg, "Chrysotlle, Treaollte and Malignant Mesothelioma in Man", Chest 93(3): 621:628 (1988) 13. A. Churg and L. De Paoli, "Clearance of Chrysotlle Asbestos froa Huaan Lung", Experimental Lung Research, 14(5): 567-574 (1988) ... -~ 14. Environmental Protection Agency: 40 CFR, Part 763, 22 Asbestos-Containing Materials in Schools; Final Rule and Notice, (Oct 30, 1987) . 15. R. Doll and J. Peto, "Asbestos; Effects on Health of Exposure to Asbestos", London, Hsr 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 Risk", Aa Rev Resp Dis (1986) 18. W.E. Fleischer, F.J. Viles, R.L. Cade, and Phillip Drinker, "A Health Survey of Pipe Covering Operations in Constructing Naval Vessels", J. Ind. Hyg. A Tox. 28:9 (Jan 1946) 19. J.L. Baltzer and W. Clark Cooper,M.D.," The Work Environment of Insulating Workers, Aa. Ind. Hyg. Assoc., 29:222 (May-Jun 1968) 20. R.L.H. Murphy, Jr.M.D., B. Ferris, W. Burgess, J. Worcester, E.A. Caensler, M.D., "Effects of Low Concentrations of Asbestos: Clinical, Environmental,' Radiological, and Epidemiologic Observations in Shipyard Pipe Coverers and Controls", N. Eng. J. Med., 23:285, 23 (December J972J 21. L.R. Liukonen, K.R. Still, R.R. Beckett, "Asbestos Exposure from Cesket Operations", U.S. Dept, of Kavy, Bremerton, Washington ( May 197B) 22. C.A7 Mangold, "The Actual Contribution of Garlock Asbestos Casket Materials to the Occupational Exposure of Asbestos Workers", October 1982, Bellevue, Washington. S. 24 13 i 14 RESULTS AND CONCLUSIONS: A circular gasket cutter of the type customarily used by workmen to cut gasket stock for flanges and machinery was assembled in the clean room on the bench. New Garlock, Inc. StyJe 900/7735 gasket stock was placed on the cutter and cut with the-sharp blade in the head of the cutter. Both the inside and outside cuts were made. Then the bolt holes were cut with a hollow punch designed for this purpose. These two tools were commonly used by workers who were required to prepare their own gaskets in the course of their work. One gasket was cut each hour for 8 hours to simulate a workman preparing gaskets during the day, and to determine the 8 hour time-weighted average exposure to the operator and any by-stariders. The attached data sheets show that: 1. The electron microscopy methods for samples at each of the 8 sample stations averaged .01 structures/cc. or less. The structures/cc are approximately equal to fibers/cc. This method determined all of the chrysotile in the sample which like came from processing the gaskets containing about 70* chrysotile. This method determines all of the fibers present regardless of size. There is no total asbestos fiber standard. 2. The electron microscopy analyses of the samples for all fibers greater than 5 micrometers in length, and 25 .25 micrometers in diameter is a direct 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 .003 fibers/cc 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 um 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 the gask*t cutting is conducted 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 low LOCATION OF SAMPLE STATIONS IN THE ASBESTOS FIBER FREE ENCLOSURE t lATTty PuP 1 ObJ # 5 vo 5 N bSNCH ss # 5r 16$ Enclosure Height * 10' 20' # /  low LOCATION OF SAMPLE STATIONS IN THE ASBESTOS FIBER FREE ENCLOSURE 1'ATf*V hxP - 10H # 5 vu 5N bNC,H 5S, 5 lo$ * Enclosure Height = 10' 20' ICE. fr SET II GasJcet Cutting* TRANSMISSION ELECTRON MICROSCOPY AIR SAMPLE ANALYSIS RESULTS CLIENT: Carl A. Mangold, CZH PROJECT: GarloeJc Research REPORT I: 112022 PAGE: 3 of IS CLIENT SAMPLE ID ESS* TEK ID CONCENTRATION CHRYSOTXLE ALL SIZES STRUCTURE SIZE CHRYSOTILX COUNTED LENGTH >5.0 ua STRUCTURES (S/CC) DIAMETER >.25 U1 CONCENTRATION LENGTH >5.0 DIAMETER >.25 , S/CC T5E-B T5N-1 T5E-2 T5S-3 T5W-4 T10N-5 T10E-6 T10S-7 T10W-8 112022 812023 812024 812025 012O2S 812027 812028 812029 612030 LAB BLANK- NSD 5 7 1 2 6 2' 5 1 NSD BLD 0.012 0.01C 0.002 0.005 0.012 0.005 0.012 0.002 X .01 NSD NSD 2 1 NSD 1 1 1 NSD 0.000 0.000 0.005 0.002 0.000 0.002 0.002 0.002 0.000 X = .ooz- Analytical Sansltivlty 0.002 S/cc NSD - No Structures Detected BLD - Belov Level of Detection S/cc - Structures per ee fibers per ce I t [ESS] Environmental Safety Systems, Inc. Gateway Corporate Park, Bldg. S 12122 Gateway Drive Seattle, Washington M1M (206) 243*6573 AIR SAMPLE ANALYSIS REPORT aJTNTi Orl A. Mangold. C.I.R. 3033 170th Place-SE Bellevue. HA 98008 PROJECT! Garlock Research - Set I Gasket Cutting REPORT ft SO-128099 SECRT DAIEt 12-12-88 PAGE 1 of 2 DAIS RECEIVED! 12-02-88 PO ft None Given CLIENT SAMPLE 3D P5E-B ESS 3D SAMPLE SAMPLE DAIS VOL (L) 128099 11-16-88 3150 FIBER FIELD BLANK CNT FIBERS BKGRND COCNT GOQNT /100 FLOS PER CC * * S 9.0 100 1.00 < 0.002 L PSN-1 128100 11-22-88 2880 35.0 100 1.00 0.006 M P-BLK-1 128101 11-22-88 0 1.0 100 N/A BLANK P52-2 ' 128102 11-22-88 2880 22.0 100 1.00 0.004 VL P5S-3 128103 11-22-88 2880 23.5 100 1.00 0.004 M PSW-4 128104 11-22-88 2640 11.0 100 1.00 0.002 M P10h-5 128105 11-22-88 2880 15.0 100 P10E-6 128106 11-22-88 2880 21.0 100 P10S-7 128107 11-22-88 2640 19.0 100 F10W-8 128108 11-22-88 2880 22.5 100 PP-1 128109 11-22-88 960 8.0 100 SAM7i LOCATICNS: Si-rple #128099 was a background saqple, taken inside 20X2050.0 enclosure. 1.00 0.002 M 1.00 0.003 M 1.00 0.003 M 1.00 0.004 i.oo jr 0.005 -- M L ,ca5 Saaple #128100 was takas north 5ft at sample station Sarple #128101 was submitted as a blank. Bulk Sampling Air Monitoring Analysis Asbestos Abatement Equipment & Supplies AIR SAMPLE ANALYSIS REPORT OJSNT: Cirl A. Mangold. C.I.H. PROTECT: Ghrlock Research - Set I SAMPLE LOCATIONS (continued) j REPORT #: 50-128099 PACE 2 of 2 Sanple #128102 vas taken east 5ft at sanple station. Sanple #128103 wax taken south 5ft at sanple station. Sanple #128104 was taken west Sft at sanple station. , Sanple #128105 was taken north 10ft at eaaple station. Sanple #128106 was taken oast 10ft at sanple station. Sanple #128107 was taken south 10ft at sanple station. Sanple #128108 wes taken west 10ft at sanple station. ` Sanple #128109 was a personal sanple in breathing sene of operator. The sacples analysed in' this report were provided by third parties not subject to control by Environmental Safety Systems. lac. (ESS) or its affiliates. Consequently, the results presented represent microscopic examinations is ESS laboratory facilities and ESS Bakes no representation as to sanple collection techniques or procedures. Analysis was performed using phase contrast microscopy under the guidelines of NXOSH nethod #7400-A. ~ * A miAisun of ten fibers per 100 fields is needed for reliable quantification. Sarples with less than 10 fibers per 100 fields are reported as less than (<) the quantification limit. ' ** ^counts of non-fibzoua material are determined using charts for estimating exposition frun the Journal of Sedimentary Petrology (v. 25, pp. 229-234, 1955). Amounts reported reflect nen-fibrous material density on sanple filter only. Legends T * Trace (less than 1%), VL * Very Low (2-5%), L * Low (5-154), M Moderate (15-25%), H High (25-40%), VK Very High (greater than 40%). Microscope Field Area 0.00785 on? Analyst (s) - TAP 2 Deposed Filter Area 385.0 sm