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environmental Sciences laboratory j*iNTSf\ 0 f=\ of The City University of New York INSULATION HYGIENE - PROGRESS' REPORTS- FROM THE INSULATION INDUSTRY HYGIENE RESEARCH PROGRAM Irving J. Seiikoff, M.D., Program Director VoI.TQ No. 1 Spring 1975 ' The Asbestos Exposure of Insulation Workmen Extensive information has been de veloped on the mortality experience of insulation workers. It would, thus, be of considerable value to have quantita tive information on the asbestos dust levels to which these workers were ex posed. Because of the long.lapse period between exposure and clinical appear ance of disease, the dust estimates of greatest concern are those of 20, 30, 40 or more years ago. While historical data are scant and fragmentary, insulation work practices have changed relatively little, prior to 1970, either in the U.S. or abroad. Thus, measurements taken prior to 1970 will also provide data of use in ^.sessing earlier exposure. Jnitcd States Data The only early work of note is the 1945 study of Fleischer and his col leagues1 who reported asbestos dust levels during insulation application in four U.S. shipyards. In this study, dust . levels were assessed using a konimeter (an instrument widely used at the time but no longer employed), and both total ASBESTOS STANDARD TO BE REVIEWED On December 7, 1971 an Asbestos Standard was promulgated that prohibited workmens eight-hour average asbestos exposures to exceed 5 fibers per milliliter (f/ml) of air. A milliliter is about a thimbleful of air and only fibers longer than five microns (about 1/25.000 of an inch) are to be counted. This level is mandated to go to 2 f/ml during June, 1976. Last year, the U..S. Court of Appeals ordered portions of the current U.S. standard to be reviewed by the Department of Labor. Of interest to insulators, the court specifically stated that in those industries where a dust level of 2 f/ml was feasible, it should be implemented before 1976. Because of this pending review of the standard, a summary of all research on the asbestos exposure of insulation workers has been prepared for submission to the Dept, of Labor by the Insulation Industry Hygiene Research Program. Because of the importance of achieving a safe U.S. Asbestos Standard and the interest of asbestos workers in this goal, we are publishing the full .report in this issue. .i - . dust levels and fiber levels were re corded. This study gains importance in that one of the yards studied by Fleischer was resurveyed during 1965 and 1966 by personnel of the Depart ment of Industrial Hygiene, Harvard School of Public Health--3 and a com parison of levels is possible. During 1964, additional data were published by Marr4 on exposure, levels at the Long Beach Naval Shipyard (Local 20, IAHFIAW). However. de tailed numerical data on dust concentra tions are only given for particles. If fibers were present, but the count re vealed less than 1 million panicles per cubic foot (mppcf), they were reported only as a trace. Thus, no average fiber, concentrations can be derived from this' study. (Continued on /toite.3). Yurd TABLE 1 Shipyard asbestos fiber concentrations by Konimeter count--1945, 1965-66 AB . fiber cone. . , . fiber font. MPPCF f/ml ' MPPCF f/mt C(1945) fiber cone. MPPCF f/ml . C (1965-66) fiber cone. MPPCF . f/ml D .... . .fiber con.c. MPPCF . f/mf Shop Activity No. of men exposed (1945) Layout and cutting Sewing and fabrication General room air 84 0.35 12.4 0.03 1.1 0.08 2.8 50 0.23 0.1 0.01 8.1 3.5 0.4 51 2.2 0.62 0.8 78 22 28- 1.76 0.27 0.3 62 9.5 10.6 8 0.63 22 0.03 1.1 0.02 0.7 The following shop activities were done at infrequent intervals and involved only one or, at most, two men: Band saw cutting 0.12 4.2 3.0 106 6.19 218 0.7 24.7 - --- : Mixing cement 0.2 7.0 1.7 60 3.1 109 0.23 8.1 0.01 Scrap grinding 0.47 16.6 ---- -- -- ---- -- '-- 0.4 -- Aboard Ship o. of men exposed (1945) Avg. exposure, all activities 467 0.02 0.7 700 2.8 98 123 l.l 39 --. . . 0.17 6.0 160 0.03 1-1 Time-Weighted Average Exposure 1.1 90 (All fibers visible) 35 1.1 -J HWBUI0004877 1945 Results Available . Average Exposures Low Tabic 1 lists the fiber exposure data obtained from over 200 dust counts by Fleischer in 1945 and also those ob tained by Murphy1 during 1965 and 1966. Using data supplied on the number of individuals engaged in the various work activities, a timeweighted (actually man-weighted) av erage asbestos exposure is calculated. A detailed analysis of the results, however, presents difficulties. In each yard, a worker's average exposure was dominated by insulation activities aboard ship. For such activities, the average asbestos dust levels reported in Insulation Hygiene Progress Reports Vol. 6 No. 1 Spring 1975 from the Insulation Industry Hygiene Research Program Editor: W. J. Nicholson, Ph.D., Pub lished at the Environmental Sciences Laboratory (Irving J. Selikoff. M.D., Director), Mount Sinai School of Medicine of the City University of New York. N.Y. 10029 Advisory Council of IIHRP Irving J. Selikoff, M.D. Program Director and Chairman E. Cuyler Hammond, Sc.D., Vice Presi dent, American Cancer Society, New York, N.Y. Andrew Haas, General President, Interna tional Association of Heat and Frost Insulators and Asbestos Workers, Washington, D.C. Fred L. Pundsack, Ph.D. Vice President, Research and Development, JohnsManville Corporation, Denver, Colo. PURPOSES OF THE INSULATION INDUSTRY HYGIENE RESEARCH PROGRAM the different shipyards varied by nearly one hundred times. It should be recognized that these fiber counts represent all fibers enu merated in the field of view of a konimeter. These would include fibers perhaps as short as 1.5 microns. Supplementary data3 on the size dis tribution of amosite aerosols in ship yards suggest that this overestimates the number of fibers longer than five microns by a factor of two. Taking this factor into account, the average of the eight-hour concentra tions of fibers longer than five microns in the four U.S. shipyards studied by Fleischer in 1945 would be from 15 to 20 fibers per milliliter (f/ml). It must be emphasized, however, that such aver ages are, highly subjective and depend strongly upon the vagaries of the par ticular work practices selected for sam pling and conditions present at that time. Similar considerations would yield a value of 4 f/ml for the shipyard survey by Murphy in 1965-66. New Techniques Used The first research that quantified as--, bestos insulation exposures using membrane filter techniques was that of Balzer and Cooper published in 1968 and extended in a report at the Dresden Conference on the Biological Effects of Asbestos in'1969.7 Their initial publication, however, enumerated fiber concentrations in marine and commercial insulation work in terms of all visible fibers, in cluding those shorter than five microns. The later subsequent publication also provided data on fiber concentrations longer than five microns. Table 2 summarizes these results. Using the information .provided on dust concentrations and the percentage of time a worker is engaged in a particu- ^ lar practice, a time-weighted average ofj 2.7 f/ml was obtained for exposures ' during asbestos insulation work in light and heavy construction, and.6.6 f/ml in,,... marine construction and repair. Cooper and Balzer noted that at the time oftheir study, approximately 55% . of the work time of insulation workers was spent using materials other than .. , asbestos. Thus,, eight-hour timeweighted average exposures for asbes- tos workers during 1968 in the western United States would have averaged less than 1.5 f/ml in light and heavy con- ' struction. Moreover, it is noteworthy that Cooper and Balzer state their sam ples were "deliberately taken under conditions where the highest dust con centrations representative of a particu lar job were being developed." Union Cooperation Obtained The environmental evaluation of in sulation work that was undertaken by the Mount Sinai School of Medicine under the auspices of the Insulation In dustry Hygiene Research Program3 re pealed , asbestos air, concentrations ' somewhat higher than those measured by Balzer and Cooper. Again using in-. formation supplied by union members and from observation of work prac tices, estimates were made of the per centage of time workmen were engaged in various activities in commercial and industrial construction. The information on measured asbes tos air concentrations obtained during these work activities is shown in Table 3. They were used as indicated to arrive at the estimated time-weighted average exposure of about 6 f/ml for insulators when working with asbestos. On the average, in the eastern United TABLE II Asbestos fiber concentrations by membrane filter techniques 1. To develop improved methods for minimizing exposure of insu lation workers to dusts and fumes encountered in their work. Job Classification Percentage of work with asbestos Light and Heavy Industrial Flbcra/cc mean All Length Lengths > 5/4 Marine Construction and Repair FibcrVcc mean All Length Lengths >5M 2. To disseminate knowledge of these improved methods of dust control wherever they may be applied advantageously and to offer cooperation, advice and assistance toward their universal adoption. Prefabrication Application Mixing Finishing Tearing Out General Time-Weinlili'il A 10% 40% 5% 30% 10% 5% P* nniiiins 10.1 12.4 2.4 2.7 12.8 0.8 Ai 6.6 8.0 1.6 1.8 8.4 .5 n7 30.4 20.0 24.8 16.8 10.6 7.1 1.8 1.2 31.5 20.2 .2 - 0.1 OQ AA HWBUI0004878 Adequacy of Standard Questioned ious circumstances indicated a moan concentration, of 226 I/ml during the removal ol'spray:of I?2 I:nil during the removal of pipe insulation: and of X.9 f/ml during the application of pipe lajrging. As with the Mount Sinai research and the Ual/er-Cooper study, short term dust concentrations during spe cific insulation practices can he ex tremely high, while samples taken over long periods of lime yield concentra tions that are relatively low when com pared with current and past asbestos standards. Summary Studies on asbestos concentrations from 1965 through 1971 by five differ ent research groups in two countries are summarized in Table 5. along with es timates made of earlier insulation as bestos exposures. They indicate that recent average exposures of insulation w orkers to asbestos are from 3 to 9 f/ml when working with asbestos. As asbestos workers in the United States in the period these measurements were taken used asbestos materials in their work less than15()'i of the time, their eight-hour average exposure to asbestos was less than 3 f/ml. It is noteworthy that these exposures existed prior to the implementation.of the current 5 f/ml standards in the U.S. As extensive substitution of non asbestos materials has subsequently taken place in insulation work, current exposures are now considerably lower. The estimate of from 10 to 15 f/ml obtained for past exposures in non murine insulations work does no/ offer much confidence that 5 f/ml, or even 2 f/ml, is sufficient to protect asbestos workmen. Forty percent of insuliJirnv-~ deaths, can he attributed te> their past occupational exposure to asbestos at such levels. A standard set at two. oreven five times lower, is unlikely to oiler significant protection to asbestos workmen. Asbestos Workers Have High IVak but Low Average Asbestos Exposures............... The high peak cxposurcs'of asbes tos workers measured by different groups ean be deceptive. These olten arc of short term and may in volve lew men. Average exposureshave universally been found to he low, usually less than current stand ards. This result leads to two con clusions: 1) Current standards mav be inadequate to protect workers, and 2) Easily accomplished control ot peak exposures can significantly reduce the long-term average expo sures. - TABLE IV Asbestos dust concentrations during the fabrication, application and removal of insulation materials General Atmosphere Breathing Zone Location No. of samples Mean Abers/cm9 Range No. of samples Mean fibcrs/cm9 Range Application of pipe and machinery insulation: Boiler rooms Engine rooms Accumulator room Mattress fabrication: Old shop New shop Removal of pipe and machinery insulation: Boiler room Engine room Brick stowage space Removal of asbestos acoustic panels: : ) 17 22.4 1-61 28 2.1 0.1-14 5 16.5 . 2.5-46 12 12.7 0-126 11 16.3 2-83 153 171 0.04-1062 45 88 0.16-3021 13 257 9-592 6 413.5 . 30-.6S4 14 16 17 3 15 25 , ." 20 . 25 -- 6 16.8 7.3 9.6 0.1-68 0.04-40 1 -47 1.5 0-7 3.7 0-17 97 25-220 91 2-490 ---- 131 48-271 TABLE V Summary of average nsbestos air concentrations during insulation work kemk Crwtp A**r*|t (IWf Carotalrrikia Li|tx **4 licit) Martm CiMrwtM Wwk Mount Sinai (IIHKP) 6.3 Bal/cr-Cooper 2.7 6.6 Murphy. Harvard 8.0* Burpess-Lyneh 2.9 Harries 8.8 Estimates of early exposures Fleischer 15-20 Mount Sinai 10- IS Ttttc oKfM iimnt trr ih.n nwknrrO t (Minuted hil< living ithrtiot liyiii H.*jf iwri|i (i|mtuKi.tiettilriMi( Hw tiy would fee U litll* 4* lull thf jfer** Fihrf ttmcM uwlwlct eil yiiiMi lihtn REFERENCES. 1. Fleischer, W, E.. Vilcs. F. J. Jr.. Gudc. R. L, and Drinker. P.; A- Health Survey of Pipe Covering Operations in Constructing Naval Vessels. Journal of Industrial Hygiene and Toxicology'.V, 9-16(1946). 2. Murphy, R. L. H.. Jr.. Ferris. B. G.. Jr., Burgess, W. A.cl al.: Fllccts of Low Concentrations of Asbestos: Clinical, Environmental, Radiologic and Epidemiologic Observations m Shipyard Pipe Covcrers and Controls. New England Journal of Medicine 2X5, 127I-I27H (1971). 3. Murphy, R. L. II.. Jr.: Asbeslosis in Pipe Cov ered Engaged in New Ship Construction. Thesis, Har vard School of Public Health, (I96HI. 4. MarT, W. T.: Asbestos Exposure During Naval Vessel Overhaul. American Industrial Hygiene Axsoci* ution Journal25. 264 2hH (P>64>. 3. Nicholson. W. J., Iloladay, t). A. and Hcinumn, IL: Direst and lihlirect Occupational Exposure M Insu lation Dusts in United Slates Shipyards. Proceeding of the International Svm|*oMnm on Salety and Health in Shiphuitdmg and Ship Repairing, Helsinki, .M) August to 2 September, 1971. ILO Occupational Salety and ^ Health Serics_No. 27. 27*47. Geneva (1972). 6. Bal/cr. j. L. anii Cooper. W. C.: Tito Wnrk'Erivi-' ronment of Insulating Workers. American Industrial Hygiene Association Journals. 222-227 (196K). 7. CtKipcr, W. C. and Bal/cr, J. L.: Evaluation and control of asbestos exposures in the insulating trade.' International Kontcrenz uber die biologischen Wir* kungen des Asbestos, Dresden. 22*24 April. 1968. Deutsches Zcntralinstituic fur Arbcitsmedi/in. pp 151* 160. Holslcinand Anspach.eds.. Berlin. H. Cooper. W. C. Asbestos in. the Manufacture of lasulatton Materials Biological Elfects of Asbestos, . I ARC Lyon, Erancc, pp 175*17X. 9. Fenis, U. G.. Jr.. Ranadive. M. V., Peters, J. M. el al: Prevalence of Chronic Respiratory Disease-- Asbeslosis in Ship Repair Woikcrs. Archives of En vironmental Health?.*, 220-225 (19711. 10. Harries, P. G.: Asbestos Dust Concentrations In Ship Repairing: A Practical Approach to Improving Asbestos Hvgiene irr Naval Ovkyurdx. Annals ot Oceupational Hvgienc 14, 241-254 (P71) I I. Harries, P. G.: A Comparison ul. Mass and Fibre Concentrations of Astvstos Dust m Shipyard Insulation Processes; Annals ot Occupational Hygiene /V, 234* 240 (197 M, HWBUI0004879 "" 1IHRP Results Reported Slate's during the I960's, over hall of the work activities of these men were with materials other than asbestos. Thus, the over eight-hour limeweighted average asbestos exposure was approximately 3 17ml. In the research that led to these data, it was reported that 'p^k exposures could be extremely high. It was not uncommon, lor example, for two to five-minute concentrations of asbestos to ranee between 50 f/ml and 100 f/inl during the mixing of cement. This mix ing, however, would consume only a few minutes time and be done perhaps once an hour. Thus, exposures meas ured over that hour, including the mix ing, would seldom average over 5 f/ml. ' Peak High. Average Low Similar experiences were subse quently reported by Cooper8 at Lyon who stated that, "Peak concentrations may be high for brief periods, while time-weighted averages are often de ceptively low." In a continuation of the work of the Department of Industrial Hygiene of Harvard University in assessing asbes tos exposure in Naval Shipyards, Ferris et at9 reported on the results obtained by J. Lynch and VV. Burgess from 81 shipyard asbestos air samples taken during 1969. Using liber counting techniques they determined a mean as bestos concentration of 0.3 f/ml inland fabrication shops and 2.9 f/ml in ship board installation work. 3 flml Exposure Three research programs in the United Slates point to the conclusion that the time-weighted average expo sure of insulators between 1965 and 1969 was less than 3 fibers longer than Jive microns per milliliter. We have direct information on asbes tos fiber concentrations, measured using the currently prescribed analysis procedures, during recent years only. Insulation materials have changed from earlier years. Fibrous glass has found extensive use while work with cork is seldom seen today. Moreover, changes in the asbestos composition of insula tion products have taken place. Pipe covering and insulation block may have had twice the asbestos content in past years as exists today. During this period, however, work practices were virtually identical to those of past years and during the period of those measurements, few controls of significance were in use. TABLE III Asbestos concentrations during various work practices Type of Work Measured Fiber Concentration (f/ml) (greater than 5 microns) Percentage of Time Practice Occurs When Asbestos is Used Column One times Column Two Mixing and Applying Cement and Cloth Covering to Insulation Material Good Ventilation Poor Ventilation Cutting and ApplyingTnsulation Block or Sections of Pipe Covering Good Ventilation Poor Ventilation Prc-Fabrication work .including Cutting Materials lor later use 2.5 4.6 5.2 11.5 7.6 Time-weighted average^ 535/85 = 6.3 f/ml 17.5 17.5 '- 20 20 10 44 81 104 230 76 535 The above practices, which occupy1 of the work lime in avbcvinx insulation work, yive nsc to a time-weighted average capoture ot 6..t l/nil. As the majority ol the oilier oc InnICS ot insulation work (supervision, collcclmn of. materials, movement and insraJhiiion ol equipment, etc. I arc relatively clean, ihc overall exposure may he tower, tin the U.S., sweeping and dusty cleanup are done h> members ol rhe l.jlxircrs Union:) In a review of work activities in commercial and industrial construction, u was found that liulc removal of inyulaiion was conducted and asbestos spray applications were very rarelv undertaken by insulators. (Asbestos wankers applied spray insulations only to powerhouse turbines.) Ii is estimated dial less Ilian two or dm*c percent ol noiim.irme tnsutalion work by members ol rhe Asbestos Workers Union is in these continuously dusty operations, i:\cn if average exposures here were Ml l/inl and die men wore no respirators, llicir overall average exposure would be increased only lo 7 l/nil when winking wiili ashesloi. Insulators Still I',\|>om.-(I to Asbestos While imidi of new insulation material contains no asbestos, pipe-coverers may still he exposed to high asbestos concentrations dur ing removal and demolition. In such work, safe procedures and personal protective equipment must be used. Thus, obtaining an effective , and safe Asbestos Standard remains of paramount importance. Thus, dust concentrations measured under these conditions have relevance . for the estimate of levels of past years. Considering the possible doubling of asbestos content of insulation materials and considering that workers may have used asbestos materials more often in the past than now, the data from these three studies would suggest that the upper limit on insulator's exposures in the United States during past years would be about 10 f/ml. British Data At the Devonport Naval Dockyard in Plymouth, England, extensive mea surements of asbestos dust concentra tions during the application and re moval of insulation aboard ship have been reported by Harries.10 These are listed in Table 4. During the applica tion of insulation material, fiber con centrations from 2.1 to 22.4 f/ml were found, not unlike those found in U.S. studies. However, during the removal of pipe and machinery insulation, mean dust concentration in various compartments ranged from 88 to 257 f/ml. and in the removal of sprayed crocidolite asbestos, fiber concentrations ranged.from 20 to 500 f/ml, with short-term breath ing zone samples showing concentra tions exceeding 1000 f/ml. Moreover, the spread of asbestos from the site of removal can be extensive. Concentra tions of 30 f/ml were found at hatchway openings to decks from the area of crocidolite stripping. High Dust During Ripout Additionally, short-term fiber con centrations measured during the variety of specific application and removal techniques are reported. High levels, exceeding 200 f/ml, occurred while mixing asbestos cement. The cleaning of debris (155 f/ml) and the sawing (55 f/mi), fitting (43 f/ml). or removing (52 f/ml) of calcium silicate sections also produced high dust concentrations. A subsequent publication by Harricsu of long-term area sampling in var-