Document mqr9Y0q5B1y6Xpz60rx705dvg

Journal of Occupational and Environmental Hygiene,'5: 87-98 ISSN: 1545-9624 print / 1545-963.2 online Copyright 2006 JOEH, LLC DQI: 10.1080/15459620500498067 An Exposure Study of Bystanders and Workers During the Installation and Removal of Asbestos Gaskets and Packing Car! Mangold,1 Katherine Clark 2 Amy Mad!,2 and Dennis Paustenbach2 1 Environmental Control Sciences, Inc., Bclievue, Washington.................................................................. 2ChemRisk, Inc., San.Francisco, California From 1982 until 1991, a series of studies was performed- .........;least30 nriUion tons of asbestos have beenused ill construction to evaluate, the. airborne-concentration of chrysolite, asbestos-. ,and\-.manufacturing;- industries : since- the..- year. t900.(l) The associated-with replacing gasketsandpacking materials. rlhese ^widespread use of:asb.estos in .the past;,has led to exposure of studies were conducted by the senior.author in response to............. .... r *..... ......... ,......... concems.raised bxaKpoSfrmiH'PwM-immwb's,',!: rmte.onsflf; < j ,. exposures associated, with gasket work: A series of studies ........ . was conducted because: results of those who worked, with.. gaskets within the Navy study, did not address the-background,, concentrations ofasbestos in the work areas, which may, have: sbh.eipesri.Lsiglnisfihcaipnytadrudes.toTthheepfrteesnetnoceftohfeassbtuedsiteoss ivnesCuloartmioendinftothme: -.iri significant adverse;, health effects.Today, asbestos, use is highly regulated. and. most .industries have replaced asbestos . materials .-with: substitutes in an,effortjo protect, workers and comply with federal regulations.......................... :h:....h.'.::...h... The ,c opaws about the rot,e.efcaSb,.CSt.os m th, e.d,wdo, pmCnt 1982 through1991 was to re-create the Navy's workpractices in.a contaminant-fr.ee.environment during an 8-hour workday of a pulmonary disease began in the United States m die 1930s and progressed slowly as more, was learned about sources of (so. the data could be compared with the OSHApermissible exposure and_.the;..pathogenesis .of asbestos-related diseases, exposure limit [PEL)). Samples were collected to characterize Much, of die historical research was. focused on disabled personal andarea airborneasbestosconcentrationsassociated......... ." , ... , . , ,. , ,,, wirfc the formation, removal, and storage ofgaskets-as well ;W0*P WiU. obvious work-related exposure to raw asbestos. as: the scraping-- of,flanges, and,, the. ..replacement: of valve. -.fibcirs. uscd; commercially, Few, if any, - industrial , hygiene packing.: The results, indicate that the 8-hour time-rweighted............ controls were followed at that time, and asbestosis of.varying ' average (TWA) exposures ofpipefitters and. other tradesmen. degrees.. of severity - was. frequently observed among highly - who perfprmed these activities were below the:current PEL and all previous PELs. Specifically, tlut highest average 8hour TWA conaan,radon measuredfor worker, manipulating .exposed workers. These workplace..CO.nditiQns.continued.until :' .. .. , '. the 1960s, When the association between asbestos and certain asbestos gaskets during this study was .0,030 f/cc. (during gasket removal andfiangeface scraping onboarda. navalship)..,.... type? of cancers became .clear and industrial.hygiene practices in the workplacebegan to re.duce.QCCUpationa.lexposures. Likewise, the 8-hour TWA breathing zone concentrations ofa ZZZZZZHistorically,. asbestos insulation, and asbestos gaskets and .worker i^movi^ and replacing osbestos valve packing.did not exceed.0.016f/cci In most cases, the concentrationswere.not distinguishable from ambient levels of asbestos in the ships packing: have.been u.sed...on pipes..and machinery'in industries r '. . .. such as refineries, powerhouses, cheimcal plants, and naval or the general environment, These results arc not surprising............ ships and shipyards. Asbestos was; considered a "magic given that asbestosfibers in gasket materials arc encapsulated-........... mineral" because, it was inexpensive and highly resistant to wphm a binder. heat and ..corrosion, -.Alternative, materials :with comparable . Keywords ^bestos, gaskets, Navy, pactangmaterials. shipyfud . properties: were: not. readily .available.: and .so., asbestos -was widely used in high heat operations internationally. Up until the r.... ^-rrtrrrrrrr.....rrrrrrrrrrrrrrrr^ ...... .' late 1960s, the.U.S. M.avy used an19si.te.and chrysotile asbestos - insulation, extensively on. pipes and.machinery onboard naval .....ships. The, Navy, published explicit specifications, regarding .... the. percentages, of.each: fiber type (amps.ite or..chrysotile). that were. to.be used in materials such. as-, insulating fe.lt, insulating ................................. blocks,'.insulating.'.cement,..sheet gaskets., and packing materi- sbestos. is a.-mineral that' was commonly used in als, Some of tlie. asbest.osr-c.ontain.ing materials used.included industrial operations in.the United Suites for the........85% amOsite insulating blocks, and 100% clnysolile insulating greater .part of the 20tli century. Because of its ...... cements.0-'"1"In the first author's experience,; chrysotile was high thermal, stability and resistance to corrosion,........ die only type of asbestos used in naval.gaskets and. packing; it has appeared in more than 3000 manufactured goods, and at...... however, qrocidolite gaskets have been historically used for Journal, of. Occupational and Environmental Hygiene February .2006 87 highly acidic applications/47 such as certain processes in pulp for- new application? in the United States was: uncommon..... and paper:plants and refineries. ......... However, due to the latency.of asbestosmelgtcd. diseases, mecti...... Themagnitude of asbestos use in a naval shipyard was;....... ical and scientific researchers:.continued to evaluate asbestos..... extremely high, Bor example, a World War 11-era destroyer is exposure and: incidence of asbestos-related disease among estimated.to have contained atleast 96,00.0 pounds.of asbestos^ workers..................... ........................................... ---........ ........ : containing insuiatio.n.(2"3'5."7) Based: on data presented by Fleischer et al.,0. naval shipyards . are.estimated.to.have used .In.-19.78,.theDepartment.of.theNayy, as.apart.of.anongoing ... industrial hygiene program, set about'collecting airborne between 100,000 and 500,000 pounds of asbestos products per montlr for new slup constxucrion during:World War.Tf.. At least. 90% of these asbestos materials, were in,am.os.ite.blankets.or asbestos, samples during the. storage, handling, and processing of ga.skets qf all.kinds in. naval. shipyards. The evaluation was ; an iimportant; undertaking because only a few: such studies...... pads, loose amosite, magnesia block insulation, and asbestos cements. All of. these,materials:.were loose, easily, crumbled, had been .conducted. The: Navy, repori/177 concluded that, even, the,simplest of general..housekeeping controls or work and handled directly by: workers. practices were.sufficient tQ.maintain occupational,exposiures... By comparison, gaskets and packing constituted a'small to asbestos:at acceptable.levels. Although the Navy achieved, fraction , of the total weight of the various asbestos products its . intended. objectivc. of .characterizing .the exposure to any onboard a naval vessel/2!3,5:6-87 and the asbestos within these ... and all: fibers in the .breathing , zone of workers, if did- not:... materials was . encapsulated -in a: binder, .' making it unlikely........measure.exposuxe levels.specifically associated with handling;. for die material to. release: significant.amounts of.asbestos of asbestos-containing: gasket materials. Breathing zone air fibersA-107 In the National Emission Standards;for Hazardous. samples were collected in work areas;.during, various gasket Air Pollutants, (NESHAP) regulations, : the Environmental -: - processing activities; however, the area was.not.cleaned prior: Protection Agency. (HM) acknowledged the.low potential for.' to tlie. commencement of the study.Furthermore, given that gaskets, and packing to release, significant amounts of fibers.-....... background samples . were not collected prior , to iiutiation The; regulations state, that even: broken or damaged gaskets,....... of gasket-.work,, -it is. ..questionable: whether the data: truly and. packing. would rarely,' if ever, release, significant:levels: reflected, asbestos exposures associatedwith gaskets, .^though..; of asbestos, even .under the conditions in. which a building is the...concentrations reported for gasket handling were gener- ...demolished.^: ........... ally .close to :0.1 f/cc, trace contamination from insulation A major goal for industrial, health and hygiene profes-, or other sources could , have easily .contributed to these sionals: in the :1960s was to. improve worksite: safety- and,....... values/177: .-. reduce, high level asbestos exposures that occurred during............. The intent of the study presented here. -.was. to. measure the manufacture, and: use of, asbestos: products . containing personal and.area ahbome asbestos.concentrations associated; . raw. and friable, asbestos that. w.ere used in large, volumes, inconstruction and. in shipyards.: However,;at .that time, small- ..with; handling of.:asbestos-containing : gasket. and packing:.... materials, by repeating.many of,the:.ac.tiyi.Ues: studied, by. tire- volume. products, and those: that..were,encapsulated were not........Navy, yet performing them in a contaminant-free environment. considered a health .risk/-*-7 In the. 19.70s, researchers and institutions,includingSelikof^^7 andthe.Interna.tio.nal Agency; for Research, on Cancer (lARC)/1^; .declared that , packing The measurements were collected between 1982 and 1991 by :Carl.'.Mango.]d,.a.certified-industrial .hygienist with..10.;years; experience working on asbestos control .measures for tire Navy and gasket materials did not pose, any conceivable health at. the Puget Sound Naval Shipyard. As a result of his shipyard hazard. There, were . some, internal .studies conducted during;.......'.experience,Mangoldwas.fairuliar.withtechniques and activity the 1970s to evaluate worker exposures associated.with, these products hut most were inconclusive: or had small sample .frequencyassociated.with gasket Hid. packing'replacement.,as well as the high potential, for worksite asbestos contamination populations. Additionally, these.tests, were likely obscured by....... from other sources. Recent interest in asbestos, exposures the liigh. backgroundJevels.from highly friable, products,,such. ;.for^w^em;!^dfii|g.;AQ^able.-.^d eneapsulated asbesto.sr. as a.sbestos.insulation/1 l.'12!-iy^7 Without adequate characters- containing materials prompted the authors to publish the data zstion of background concentrations, it is virtually impossible : from this comprehensive series of. studies.. to identify the source ofi.exposure in . worksite, studies .when................ multiple asbestos products.areused in close'proximity.'to.each h/lETHQD.S;..................................................................................... other.;;........................................................................................................................ ;.............................. During the 1960s and 1970s, the Navy pioneered changes HH he objective of this series of: studies was to evaluate: in the use of asbestos by implementing dust control devices, JL potential asbestos exposures tp wotkers: and bystanders enforcing the use; of respirators,- and replacing asbestos with - during the removal and installation of asbe.stps-containi.ng alternative materials as they became available. As sources of gasket and packing materials. Personal and area airborne free fibers, were eliminated or contained, .the Navy focused........asbestos exposures: wer.e characterized over the.co.urse.of an 8- on evaluating low-level.spurces,ofexposures, such.as-gaskets. ho.iir workday, as.workers.performed gasket and packing work. Oilier industries followed ihe Navy's lead in. implementing industrial hygiene controls, and eliminating the. use. of friable The activities studied included scribing of gasket materials,, formation of .asbestos sheet gaskets, opening of flanges and asbestos-containiagproducLs. By the 1980s,ruse .of.asbestos: removal of gaskets, cleaning of flange faces.using p.utty.kiiiye.s. 88 Journal of..Occupational and Environmental Hygiene February 2006 and wire brushes, and removal and installation of asbestos........Although it is a more powerful analytical method, due to the packing from valves,. ....... ;higherresolution forepuntittg.smallerfibers and differentiating; In.these.studies,..emphasis, was placed on..characterizing 8- fiber type, its use. ..in'; worksite regulatory compliance is a.'."''. . hour TWA exposures. ..so. that the magnitude of exposure to........ '.supplement to PCM data by providing'information regarding.... the maximally, exposedworker (e.g.,. a worker who replaces. : fiber type and size. PCM analysis is the most important method gaskets or packing in the. field throughout,the course of the.......for. comparing exposures to the OSHA 8-hour TWA PEL...... day) could be determined., The; time, required to. perform The TEM analysis;that was performed served to. confirm;the tasks associated! with-gasket and packing replacement makes;;;;;;;;;.',';.'.:absenc!5..of-.asbestos.and non-asbestos.ffb.er contaiuinatipn, as;.. it unlikely that a worker, would perform more than eight: indicated by tlie PCM data. B ulk samples were collected only in. . replacements (of either gaskets or packing) per day. Based the 1989 series ofstudies and were analyzed by polarized light on professional experience, with Lite exception, of a site-wide nticroscopy (PLM). The rationaleTor assuming that the gaskets .shut-down, or ..overhaul, ib is, uncommon, for a millwright or and. pacldng .contained .asbestos is., discussed ;in tlie Methods.... other craftsman to replace more than two gaskets...or packings ..section for. each study, in a single day. . This series.of testing is unique among the existing published By simulating this work, it was possible, to repeat. tlie : studies on gasket.. and packing removal and replacement activities several times; throughout the course of: the. day....... because it combines.elements of both.worksite and simulation because all the tools, raw materials, and flanges were already ..studies,.Like simulation.studies, this series of studies empha- set up at tire workers': workbench. Thus, the measurements . sized the characterization and/or the .elimination of sources collected in these studies likely represent, more severe, corn of asbestos contamination, so thatall of the measured airborne ditions than those experienced by workers in the field. In asbestos.could be attributed to tlie work activity of interest. 'Die practice, workers typically receive their assignments, go. do ...limitationofsimulatipn. studies,is. that they, may .be.perforrned.... .storerooms .and lockers .to retrieve the. appropriate .materials by scientists, .unfamiliar,.with..typical.worker Techniques- or, and tools :for. tire.,job.,: and change into/ their work.clothes. daily- activities, WQrksite,s.t:udies.;o.ver.cqme-this'.by sampling Additionally, workers must navel to each location where tlie workers; as they perform their daily .tasks; however, these . flange or valve work will be conducted, determine how tlie.......types of studies are often subjectto contamination from other flanges or valy.es, will be. accessed, and .then, remove pipe activities or general contami.nation.in.the area. In this.series of .insulation ,and. bolts 'before,.any gasket.', replacement, work; is..... : studies, the. first author's previous employment history lent him |||k performed. The actual timespent forming a gasket or removing........considerablefamiliarity.with the activities ofinterest, as well as 111, and installing packing orgaskets is.a small portionof the oyerall the. scientific methods' for evaluating exposure and minimizing ': workday,. -.contamination. Short-term excursion,samples: were not collected in this. These studies on gaskets- and. packing took.place' over ... series of studies for two reasons. First, the s.h.o.rt-term airborne: several -years.-To. clarify, the differences between each study,. concentrations,presented-in the 1.978 Navy study-were nearly......... the methods are discussed separately. uniformly below both ;the current and historical excursion ....... limits F7),Considering that the Navy study is likely, an o.veres-.......... ............... timation of genuine.cxposure, it seems unlikely tiiat any short-.........Test I: Disassembly and Assembly of Flanges tenn-samples collected, in .a contaminant-free environment. Containing Three Types of Gaskets (No Flange Face would be greater than those concentrations measured, in the. Cleaning), Conducted In 1982........ ......... Navy .study. Second, the .exposures experienced by a worker . All simulation work, was: performed inside, an enclosure repeating a task eight times over the course of an 8-hour sample measuring 3.. x 3 x 3, meters (27, cubic meters) that was made.it unnecessary to collect short-term excursion samples. If constructed of PVC plastic piping and 0,01 cm polyethylene theairbomeasbestos concentration .du.e.t.Q one.repetition ofthe ; plastic,including tiieffoo.r,Th.is fyp.e.of.enclosure was.selected.. task was.in.excess of the excursion limit, then the 8-hour TWA........ because.it represents the smallest practical work space in which concentration for eight repetitions ofthe laskwould likewise be........ gasketworkwould normallyhave been conducted, No..dilution.. in excess of tlie PEL. Therefore, it. was determined that the best, or local exhaust ventilation was used. The work, area was .......way to. evaluate exposure to,a worker;.whose.responsibilities........ cleaned between each activity............. include, frequent gasket: and packing replacement would be.: Standard niediunwsized flanges, (approximately 8 to 16 .cm. to collect' samples, during'.several repetitions of the tasks over in diameter) were, taken fronv.a .deconimissioned.:.naval.'.,ship 8 hours... and were cleaned thoroughly prior to the study to remove Only phase contrast microscopy (PCM).analysis was con- any surface contamination. The mechanic assembled and dueled on the filter samples, during the. phases of this study.........disassembled flanges containing gaskets intemfittentiy over the' performed prior to 1989. At. the .time, transmission election, . ..course Qf .an.8-hqur day, similar to the typical.-work.activity in micrpscopy..(TEM) .analysis: was. not :a standard .analytical tlie.removal andinstallation of gasket materials.,However, the method: for airborne asbestos and, even today, TEM .data,axe; .flange faces were not cleaiierl in.any way. One day was devoted riot directly comparable, to the Occupational.Safety and Health........ to. each of tlie three ..types of gaskets that; were, evaluated: Administration (Q.SHA) permissible, exposure. limit (PEL).. spiralwqund, braided, and encapsulated,The simulated work; Journal of Occupational and Environmental Hygiene February 2,006 89 activities evaluated included the storage, handling, removal, and installation of asbestos-containing gaskets. The mechanic remained in the plastic enclosure for two 4-hour work periods separated by a one-half- hour break. At. die beginning of each of the two wprk: periods, die mechanic was fitted with two. open-daced 3.7 mm, 0-8 -jm mixed.eellulos.e.ester (MCE) filtercassettes positioned in die breathing zone on the left and right lapel, for a total of four samples per day; Each breathing zone sample was collected for 4 hours .at 2. L/min, Additionally, two area samples were collected per 4-hour period, each one on an opposite side of die sealed enclosure.-AH-.Samples were, analyzed by PCM. analysis using die P&CAM 239 Method, die. precursor to National Institute for Occupational Safety and Health (NIOSH) Method 7400, Bulk, samples were not .collected from die gaskets removed in this study. Based on the..ship's naval: : provenance and the appearance.of the gaskets, die first author was confident that most, if not all, of the gaskets contained asbestos. Test II: Various Gasket Work, Conducted in 1982 Simulated work in this phase of testing was conducted.. in industrial work..areas, where asbestos-containing materi als were routinely processed, rather than in :an enclosed, contaminant-free workspace, Flanges \yere taken from an out- of-service naval ship, and die exterior surfaces were cleaned thoroughly prior to the study. The work area was not cleaned or decontaminated prior to the study, but .samples were collected for 8 hours each for 3 to 5 days before, any gasket work was performed to. evaluate background airborne...asbestos: in the ... work area. Personal,air samples weire.collected for 8 hp.nrs.at.2 IVmin: on open-faced 37 nun, 0.8 /am MCE filter cassettes placed in the breadung zone of workers conducting, die gaskefactivities. of interest. Gasket formation activities included the use of ball peen hammers, hand-operaicd mechanical punches, machine punches, machine ..shears,, machine .nibblers, and. the use of hand shaping tools such as kiiiy.es, scissors, and scribes. Other activities evaluated, included gasket .^installation on a clean, surface, gasket removal with, hand scraping: of the flange, surface, and hand scraping- of-the; .flange, surface only (no. gasket removal).. The, workers, wore clean work clothes or plastic-impregnated coveralls .during each day of the; test-.. period. ..... The activities were performed by workers at a typical rate over the course, of the day,, which ranged:from intermittent to .continuous. The intent of tliis .test.was..to .compare, die 8-hour TWA airborne concentration.duriug gasket work to the average- background airborne asbestos. All samples were analyzed by PCM analysis using the P&CAM 239. method. Bulk analysis, was not performed. Theikst authorhad.knowledgetiiat tke.gg.s-. kets being formed, at this industrial site contained asbestos and, as widi tlie previous study, his belief tliat die flanges contained . asbestos, gaskets, was. based on his:knowledge of the flanges' source. Test IH: Disassembly of Ship Flanges and Gasket .. Removal, including Flange Face Cleaning, at Two........... Different Worksites, Conducted in 1983............................ ... -The purpose ofthis, study was to evaluate, the concentration.... of: akb.ome. asbestos while removing gaskets and cleaning..... . flange faces within an actual ship. The study took place in two. phases: one onboard the IJSS Gypsy (A.R.SD-1) and. tire...... other using;valves taken from a formernaval ship, the Offshore L Both ships were World War n vintage tnmsport vessels and were ideal for tliis experiment because they contained [flanges that had probably never been opened during die lifeof the strip (meaning.they, had been in place for nearly 40 years). Many of the flange bolts had to lie cut with, an oxygen-acetylene torch..... because they had. been frozen by age and corrosion. In the first phase of the study onboard the,(JSS Gypsy, an auxiliary ship, 20 asbestos gaskets were removed from flanges on the ship and the flange faces were scraped with a putty.... knife,-The. gaskets were removed, from four flanges .over die course of each 8-hour workday for 5 .consecutive days. Each day, four samples were collected for. 8 hours at 2 L/min on open-faced 37 nun, 0,8 p.m MCE fiIter;cassettes placed on the. right and left.lapel, of the workers removing the gaskets, .The . workers wore clean clothing each day to minimizedie effects of contaminated.clothing.Although the ship's insulation had been.... removed long before the study took place, background samples..... were collected onboard the ship and away from the work area..... to verify that the background concentrations of asbestos were negligiblein the second phase of this study, 30 pipe flanges were removed from die first and second deck'.of the Offshore I (an LST, tank landing ship) using an oxygen-acetylene,torch.The flanges, still intact, and unopened, were, moved to. a remote, asbestos-free site and cleaned prior to the study. At the study site, each flange was placed on a clean, piece of polyethylene .:. plastic and,disassembled. Once the flange was opened, the. gasket was removed and the flange.surfaces were scraped with a putty knife in die mannertypicalof shipboard procedure......... .......During this second, phase of. testing,. six .flanges were: disassembled during each 8-hour work day over a. 5-day... period. Two . breathing; Zpne -air samples were collected for 8 hours at 2 L/min on open-faced; 37 mm, 0.8 gni .MCE filter cassettes placed on the right and left lapel.of the worker,.. Duplicate environmental air samples were also collected prior to the tearing,to confirm the. absence, of ambient asbestos ... contamination. All samples were,analyzed by PCM using the NIOSH P&CAM 239 method. Bulk analysis was not performed on the gaskets removed during tliis test. However, die gaskets used in the following test (Test IV) were also taken from flanges on the tJS.S Gypsy and were analyzed by PLM.... The results of the bulk, sample analysis are presented in die.. ...Test IV section. .. Test IV: Gasket Formation, Removal, and Flange ...Face Cleaning, Conducted in 1989, ........The primary purpose of this set of studies was. to evaluate bystander exposure to asbestos due to -gasket removal and : .\......... 9-0 \.................... V.................. Journal of Occupational and Environmental Hygiene February 2Q06 replacement activities, although worker breathing, zone sam ples were also. collected. Air .samples.' were,collected.during, gasket formation, gasket removal, and the cleaning of flanges from valves, midpiping taken from.the. USS.Gypsy (ARSpr 1); This;study, was: similar-to .the previous' study- performed; in 1983, yet it characterized additional gasket:.formation and removal activities and. included ah evaluation. of bystander. exposures. Some of the. .gaskets collected during this study, were taken from ftanges, that.contained bolts ..that were.frozen in place with corrosion and showed no indication of.being... opened, since the vessel was. built. Prior to the study, all .of... foe. residual.'asbestos insulation onthe outside of. the piping was removed to prevent contamination when the gaskets were removed from, the flanges.. The study took place: in. a. new metal building to ensure that accum.ulatipn.of.dust er previous asbestos insulation contamination was not present. Electron microscopy samples showed that the amount of ambient asbestos in the facility was 0.002 flbers/cc or less for allsizes of fibers, A clean work bench.:was placed in the center of a. clean enclosure measuring 6x6 x 3 meters high (Figure.: l),There was no ye.ntilatiQn in the enclosure:and there were no.air ex changes as the study took place. The gaskets,were processed on the bench,according to thedescriptions given by some workers. All of tire work was performed by ,the first author or by a pro fessional mechauic. PlasLic-impregn.ated protective clothing1 (Tyyec) was worn by the operator.to. minimize contamination and prevent confounding personal air measurements with dust resuspended from worker .clothing. The,tests., were, conducted over an 84iour workday, so. that the data could be. compared to the federal occupational standard for asbestQ.s, One personal.... sample, was collected in the breathing zone of the operator.. at 2 L/m.in. Eight area sample stations were.set. up with, four stations.bemg wifom 15 mof the workstation andfour witlmi d m at approximately 10 Urnin. Both personal tmd.area.smn.ples... were collected on open-faced 25 mm, 0,8 /zm MCE filter cas- . isettes. The. area samples were analyzed by. both TEM andPCM using NIOSH methods 7400 and 7402! The personal samples, were;analyzed by PCM' using NIOSH method 7400. Samples of the removed and installed.gaskets were analyzed..by. LM. Gasket Formation Using Hand-Held Tools Asbestos exposures associated .with gasket formation using..... hand-held, topis were .evaluated..over foe course, of .4 days,. Hand-held, tools used for gasket formation included a .scribe, ball peen hammer, circular cutter, hollow punch, and hand... shears! The new gaskets, were made, from Garlo.ck gasket. material.(style #9.00/773.5, Oarlock Scaling Technologies, Inc.,... Palmyra, N.Y.), containing about 70% chrysotilcasbestos. This type of g.asket.material, was.typicalipffoe types.used from foe 1940s to .1970s. Activities were,repeatedintermittently, similar to the rate of a worker preparing gaskets, throughout the day........ ..... The following gasket.forming actiyities.:were.studied, each. on a. separate, day m Scribing of gasket.- material: Two gasket, stock pieces, were .marked with tire- scribe .each hour for 8 hours, for a total, of ..... ,16 gaskets overfoe courxe.pf the 8-hour day;............................ 10' North 5' North 10- West 5' West Work Bench 5` South: 5'East 10* East 10" South FIGURE 1. Location of area sampling stations, in Tests IV and V Journal of Occupational and Environmental Hygiene .February 2006 91 i2 Gasket cutting with a circular cutler: One gasket was cut; each hour for .8 hours, for a total of eight gaskets.................. m Gasket cutting with .a ball peen hammer. Both the shape of the gasket and the bolt holes were. cut. using the ball peen .....hammer. One gasket was fomied each hour for 8 hours, for . a total of eight gaskets, a Gasket cutting with hand shears and a hollow punch: One .gasket was .formed each hour far g.ho.urs,for a total of eigh t., gaskets. ............................... V.'.......;............................................ Removal of.Asb^stoaliSasJteB.ts......................................... One day was spent evaluating asbestos exposures during the removal of asbestos gaskets. Eight flanges..were opened.. over :an 8~ho.ur sampling period - to. determine.the- 8-hour TWA associated with the/removal of gaskets from flanges. Although the gaskets were pried from the flange using a putty knife, the flange faces, were not. cleaned, Ail of.the .removed gaskets.. were, similar and determined, to.: contain chrysotiie asbestos,. Flange Face Cleaning ........................ Three days were dedicated to evaluating asbestos exposures during flange face cleaning. In this,evaluation, a hand scraper, hand, wire.brushand power, wire brush were used, to remove any residual material left on tire flange face after, tire gasket had been removed. The work. with, each tool was performed on a separate day and.repeated at least eight times over the 8-hour day. All of the gaskets taken from these valves were verified to contain chrysotiie asbestos. and therefore the gasket residual also contained chrysotiie asbestos,;....................1......................... When cleaning the flange face.with, the hand wire brush, ... it was necessary for the worker to also use a scraper to clean the surface.: The power wire brushing involved the. use .of.an electric drill, with a circular, wire brush attachment. Test V: Removal and Replacement of Valve Packing, Conducted in.1.99.1....... ..... .. The,air sampling during the removal and replacement of valve packing was conducted,using two dozen.medium..sized... steam valves, obtained from, a municipal, steam plant The exterior surfaces of; the valves, were, cleaned to remove any residual asb.estps-containing.materials adhering, to the valves witliout,disturbing the packing nuts and asbestos-containing packing material in any way,.... A dean workbench was: placed in the center of a clean enchasme measuring 6 x .6 x. 3 tn high (Figure 1)..There was no.ventilation in the enclosure .and there were no tur exchanges as the study took place, -The. valves were placed beside the workbench so that one valve after anothercould be processed by removing the old. and installing; the new packing material. The first author and an assistant, both wearing breathing zone; sampling cassettes, worked on eight valves over the course.of approximately 4,5 hours. The personal samples were collected at 2 L/min and tire area samples at 10 L/min on .25 mm, 0.8 /mi MCE filter, cassettes, ftl.astic-impregn.ated protecdv.e.clo.tlung (18'vcc) was worn by the. operators, to.epntrol for (lie potential release of non-asbestos fibers.from.street clothing,:and dust7 ..from shoes. Eight, area sample stations were set up-, four were :1.5 m away from the work station and four were 3 m away. Area samples .were: analyzed by- both.,PCM and TEJyt using. NIOSH methods 7400 and 7402, respectively. The personal samples .were analyzed by PCM using MOSIf method 7400. Bulk imtdysis. data from the packing used in this test ate not available.. ..... ..... .....The valves were, disassembled and the old'packing was .removed.: New. packing .with similar...asbestos:contentto-, that - used .during..' the 19,5.0s.. (Gariock, styles 127 and 733. com.; taining about 70% .chrysotiie asbestos), was measured,, cut, and' installed, in', the valve; This -process continued, for more .than 4 hours and, since, .it is. .unlikely that a worker would ...replace: packing for. any more than eight waives per day, it was assumed tliat the. asbestos concentrations measureel during .. the sampling period: were representaUve. of the upper range of concentrations a worker would experience over an 8-hour workday, B ased.on professional experience, unless the circum stances were, unusual, it W common for a millwright to replace packing on only two- to three valves' in a single day................................................................................ .................. RESULTS Hp ables 1-/V present the data from the.studies described.-. JL above, including .sample:.averages:.and. standard devia tions. For samples below, the. detection limit, one-half the limit of detection was used for the .calculations,............. Test !: Disassembly and Assembly of Ranges Containing Three Types of Gaskets (No Flange ..... Face.Cleaning) (1982). .. As shown, in Table I, the assembly; and .disassembly of: flanges, w.ithout any flange.face.cl.eaning, pro.duced,.asb.estos, fiber: concentrations that .-.were at or below. the:lower..limits., of detection. Average, breathing zone 8-hour TWAs ranged from 0.004 to 0.005 f/cc for the different types of gaskets, with st.andru'd( deviations. less:; than or equal to 0,001 f/cc. Average area samples were at or below the limit of detection of 0.004 f/cc.... 77................................. 1ZI I1LZ1Z1IZL Test il; Various Gasket Work (1.98.2).. ....... This phase;, of/the study involved gasket removal and ; formation in an environment that; was. neither enclosed .. nor-. . asbestos-free,: thereby^.characterizing both the- ..background and.: the combined . .background, and. activity-related.,.airborne, asbestos concentrations, associated, with.the.worksite. Many pi the. activities or areas sampled, as reported, in..Table/II, were, .-shnilar to, those sampled .by :the,Nayy: in Uieh 1.978.rcportT7! The area samples taken before the work activities commenced had ayerage.cpncentrations ranging from0.02to 0/11 f/cc, with - smndmd deviations as high tis, 0,0.7.f/cc. The average,8-h.0ur. ' TWA .exposures,(including background. sources of asbestos) 92 1 Journal of Occupational and Environmental Hygiene February 2006 TABLE I. Airborne Concentrations of Asbestos for Workers During Disassembly and Assembly of Flanges Gasket 'type............. Spiral wound metal encased Braided Encapsulated sheet ist44iour TWA" -.0.005 0,005 0.005 Asbestos Concentrations by PCM (f/cc)4,B'c Breathing Zone..... 2nd 4-hour 8-hour. TWA" TWA Std Dev." Area 1st 4-hour 2nd 4-hour TWA".... .....TWA" 8-hour TWA 0.003 0.004 0.006 0.005 0.005..... .... 0,005; 0.001 0.001 0.000 0.002 .. 0.002.... 0.002 0.003 .... 0.004 .... 0.004 0,003 0.004 0,004 Std. Dev" 0.000 0.001 0.001 Note: Flanges,'which w.erc disassembled and assembled over an B-hqur wprkday (no.flange; face cleaning) Qontaiiicd .tlirce.lypcs.of gaskets. Sampling was conducted: in 1982............................. ....... <*Thc limit-of detection was 0,004 f/cc,. ...................................................................................................................... B PCM analysis counted all fibers >5./rm in length.with.at least a 3:1 aspect ratio. c For nondctectable samples, average and standard deviation were based on 1/2 the limit of detection. Ttoo samples were collected in each 4-hour sampling period for each gasket type. Value represents standard deviation of all four samples collected. ranged from 0.02 tq 0,14 f/cc,with stmidarddeviations, as.high Test III: Disassembly of Ship Flanges and Gasket.......... as 0.05 f/cc......................................... ..................... Removal,. Including Flange Face Cleaning, at Two ;;;;;;;;;;;;;;;;; Statistical comparisons between asbestos measurements for....... Different Worksites (1983) background and specific work tasks.demonstrate the..difficulty. The 19.83 study involved the collection of airborne asbestos; in quantitating low-level asbestos exposures associated with a samples while disassembling flanges at two worksites: on a particular source when background^^env.ixonmental.eomamina."........ship'--and in. a buildingiThe.^ta-from the.removal .of: gaskets. .1.1. tion is present. The data collected during each gasket activity........from.flanges both,onboardashipandin.a buildingarepresented were tested for distribution lit using the D'Agostino Test jn Table III. In. botli settings,, the background concentrations....... and were found, to have, a, lognormal - distribution at a .95% ofasbestos .were minimal,.0,004 and 0,003. f/cc, respectively,; confidence leyel.d?/-The two-sample Student's t test of the ;both with a standard deviation of O.OOl. f/cc. The average of. log-transformed data showed no difference at a 95%.con(i-..... the 20: personal breathing zone samples taken onboard the..... denee level between background concentrations, and activity....... USS Gypsy was 0,030 f/cc,(stan.dard deviation of .0.021 f/cc).. concentrations, in which five samples, were collected. for each The average of the 1.0 breathing zone samples collected at the...... activity. The Iwo-sainple Student's t test of Lhe pooled activity onshore site was 0.023 f/cc (standard deviation of 0.013 f/cc). data showed no statistically significant difference between These data were tested for distribution fitusing the D'Agostino..... background and activity measurements (p --- 0.073). Test arid were found to have a lognormal distribution at a 95%. TABLE II. Airborne Concentrations.' of Asbestos .for Workers During the: Performance, of Various. Gasket; Activities 8-Hour Asbestos Concentration by PCM (f/cc)4 Breathing Zone Background Site n" 8-hour TWA Std.Dev. n" .. 8-hour TWA Std. Devy . Sforage ofgasket material:.......................................... Q. Hand-punching 5. Hand operated mechanical punch 5 Machine punch, 5 Hand shaping table .(knives., scissors..scribes) 5 Machine shearing;......................................................... .5... Kibbler machine. 5; Flange opened no scraping (gasket installation). ;37 Flange opened, scraping with knife.......... . 3.: NA. NA ;5:................ 0.02 0.0 i ....... 0.06 0.01 5.: 0.04 0,03 0.02 0.02 5 0.02 0.00 0.11................. 0.04..............5............... 0.09 0.07 0.04: 0.02 5 0.03 0.03 0.09 0.04 5 0.07 0.03..... 0.14................. 0.05 5 0.11 0.05 0.03...................0.02............. 3 0.03 0.00 0.03: 0.01 3; 0.02....................0,01 ..... Note: Sampling was conducted.in 1982 and inyp!yccl..c!)aiactri;iaci.o.n.of;work aclivities.over an S-hour workday, limit of delcclipn unkiiown.. HA-uot applicabjc,- APCM analysis counted, all fibers. >5 /m in.leiigllr.with.at Ieast.a.3.:.l-aspect ratio. .......................................................................................... A,Each sample was collected for 8 hours. ................. .......................................................................... dNo.wo*acjiyiti.^;.wi^,-cpndu)^.hiihg.g^^_!^pwge.S6a2!::ili:"................................................................................................................................................ Journal of Occupational and Environmental Hygiene February 2006......................................... 93 TABLE III. Airborne Asbestos Concentrations for Workers During Disassembly of Ship Flanges and Gasket Removal 8-Hour Asbestos Concentration, by PCM (f/cc)A>B Source of Valves- Study-Site Dayc Breathing Zone __ (Background nD Average Min.-Max. Std.Bevf n/J- Average Min.-Max; Std.DgV. USS Gypsy^ Onboard ship 4- Offshore lF Building (on land) ..... 6fc 20 0,030 10 0.023 0.01-0.08 0.01-0.05 0.021 0.013 5 0.004 0.002-0.005 ...0.001............. 9 0.003 0.002-0,004 0.001 No^SampUng?w^.PWdact^M.1.983;^4.wv.olx^fl^gfi.f^cleaningap^o<Uffe^twocksites.OYec.anfirh9!4r^9jJal.9,Y-Limit of detection unknown. -PCM aiialysiscount^aUfibas >5/rm mlength.with at least u.3:l aspect ratip. "U is assumed that all fibers detected. wets ........................................................................................... cStudy took place oyer.the .course of 5 days,.................................................................................................................................-................................................................. -Total number of.sampies collected over, the5. flays.: ...................... ...... -Four lapel and one background samples were collected for.8 hours each day; four valves .werp.prpeesssd.pcc.day for a total ot 20 valves, (.Two lapel and .two b.ackground sgniplcs were collected for 8 hours each day; however, one of die background s.amples .was lost. Six :yalMC5..WeP?-pro.^ssc(i.p,er day fora total of 30valves. confidence les'el.(ls) The two-sample Student's t test pf.tlielog-, transformed data showed no statistical difference, (p = 0.5.8). between the mean asbestos concentrations measured in the two h.set;fatgg,""-------- ........................... .......... Test V: Removal and Replacement of Valvo................. packing ..... Table V shows area and worker airborne asbestos con centrations during the. removal. and replacement of valve . packing. The. eight; area samples had-.an: average.. of 0,00.8 Test IV: Gasket Formation, Removal and.Flange Face Cleaning (1989) Several of the methods used by. workers in the field to. remove; and replace; gaskets are. listed in Table TV. During gasket' formation activities, using circular cutters, hand shears, .. ball peen: hammers,. or scribes,, the average- breathing zone concentrations were.at or below the liinitof detection of0.005 f/cq by PCM.aniUysis, The area samples.during the siunegaske.t: .formation.^^acdyiUes'-wroi&ss;& to .0.006 f/cc'by-- PCM analysts; and less than or equal to .0 003 f/cc by ITEM analysis. All of the standard deviations of the. area samples. were less than or equal to 0,002 f/cc. Similarly, gasket removal, and flange..scraping with a putty, knife created breathing zone f/cc by ITEM analysis and an average of 0.004 f/cc. by PCM. analysis. The standard, deviations of tire, two.datasets were 0-003 and 0.001 f/cc, respectively. By PCM analysis, the operator breathing zpne .concentration was below the : detection.li.mi.t.qf.O.Ql l f/cc and,the bystander breathing zone concentration was below tire detection limit of0.009 f/cc, Since .a ..single, .sample;was. .collected each' for;the worker, and the bystander during the packing activities.(as compared to several samples, collected, during.gasket .activities),,both gamples.were submitted for a blind recount. The recountyielded operator and assistant breathing.zone concentrations of0,016and0.009 f/cc, respectively, indicating.that there was little vanability in the 0Qniiiig-.!ancthod. z;------- ----- ........................................................ and area asbestos concentrations less than 0.005 f/cc by both TEM and PCM analysis..................... ;............................... :................. QISCUSSION ;;r;zzz:=ZZ;zzzZTIZZZZDIZZZ............. .... Band and power wire brushing created higher and more varied data. The breathing zone:8-hour TWA airborne con-........FT|P his series of studies, evaluated worker arid bystander centrations were 0.007 f/cc- for hand wire brushing and .0,00.9 1- exposures during, various types, of; gasket..and: packing f/cc for power wire,brushing (PCM analysis), The average....... work, including installation, removal, cleanup, and gasket area 8-hour- TVVAs for gasket: removal .'.involving; hand. wife. '|gt-m4Uou.E.Over^l,;:;Lhe(t.kita: huhea^ brushing and power wire, brushing samples were. 0.024 and......... exposures to workers.jjerforming these activities throughout: 0.028 f/cc by TEM analysis, while the PCM. analysis of the.......the 8-hour workday, were well below the. current QSHA 8- same samples yielded average concentrations of 0.003 and hour TWA exposure, limit of .0,1 f/cc.and all previous:OSTIA 0.001 Fee, ,respectively. The staudarcl deviations,-of the PCM;.......-exposure'.limits; Gasket.removal without flange face cleaning data for both types:of wire brushing samples were less than;...... yielded.the.lowest airborne asbestos concentrations, with most...... or equal to 0.00.1 ffee, yet.the: sKmdard.deviations of the TEM......measurementsfal.ling.below the limit ofdetection of 0,004 f/cc data was 0.012.f/ccfor hand.;.wire bni.shing and.0,Q07.f/cc.for- by-(PCM-.analysis. (Table-I).-The-.liighest.concentrations,^ .ex power wire brushing............................... ...........;............ ;...... zvrv. eluding those reported ' in Table II, were measured during... .Bulk.samplingindicaterl.thattlie.rempvedgaskets.contained...... ...the, disassembly, of.flanges: onboard a. ship (with flg.nge face; 60-80% chj^'sotile asbestos aitd. the installed gasketscon tained: : cleaning),'with 8-hour TWAs of 0.03 f/cc by PCM analysis 70.-80% clirysQtUe.asbest.QS, with no other asbestos .fiber types. (Table 10). The breathing zone concentrations reported in: identified,. Table Hv/ere nor significantly different from the.background 94 ...Journal'of Occupational..and Environmental Hygiene... Februaiy 2006.:..:.:;......... ....................................... ...; '............ ... ..si I- TABLE V. Concentration of Asbestos for Workers and Bystanders During the Removal and Replacement of Valve Packing Activity Asbestos Concentration by PCM (ffcc)4,4 Asbestos Concentration by TKM (f/cc)^'^ Background Concentration Breathing Zone Area Area by TEM5,5 Worker5 Bystander5 n Average Min.-Max. Std. Dev. n Average Min.-Max. Std. Dev. Packing removal and installation 0.002. <0.011 <0.009 8 0.004 0.002-D.006 Q.0Q1 8 0,008. 0.002-0.012, 0.003 Notes:- Sampling-was .conducted',in 1991 and involved characterization of area concentrations..over, an B-hQur.Workday...Personal.sample!;were.collected, frpm a worker and a bystander for more than .4 hours. There was noventilation in.tiic room. To evaluate; analytical yari.abiliiy, the.;wp.ikst::and bystander samples were recounted. The results were 0.016.f/cc (worker) and Q.!)()9 f/ce.(bys.Ui.rider). ................................................................. Zi". ... ZZZI ZZZ' . 'Z. ZZ. ZZZZ ^PCM analysls counted all fibers >5 fitn in length with at least a 3:1 aspect ratio............ ............................................. .................................. ......... ^Samples.below the liinit.of detection arc reported as less tlian (<) the quantificatiori limit.' -fi-TEM analysis counted iiU.chry socle asbestos (ibccs >5 /an in.lcugth with at least a 3:1.aspect ratio.................ZZZ..;7.Z.Z ... ZZZZZZZJ.J ,'C''....'.'.'..Zb. .' --llrcse values represent the asbestos concentration measured!))' TEM,not the.corrected PCM concentrations, ;; ZZ . . ............................... u . 1. concentrations,."; Even, though .some of the - breathing. zone samples were in excess of the current OSHA PEL of 0.1 f/cc, the corresponding background concentrations..were also close; to. 0.1" f/cc In the studies in which both TEM and PCM analysis, were conducted, the.concentrations reported by PCM analysis wereoften greater than those reported by TEM analysis, tin the case of hand wire brushing, power wire brushing, and packing. replacement, this, wasnot the case. TEM analysis, unlike PCM, counts pidy.asbestos fibers, so it woulb.seem that TEM analysis: should yield lower counts than PCM data. However,. TEM provides better resolution than. PCM and may count two fibers when PCM would count one. ...... One. shortcoming in the studies reported here is the lack of;bulk sampling data for., many .of;tlie. gaskets;.:and;: packing that were removed and installed. Several of the airborne. asbestos concentrations were close to .background: concentrations, making it especially desirable to! verify that . all of.tiie. materials .handled .contained,^asb.es.tos/.Hpwcyer,' in; conducting these studies, there are several.reasons that the first .author was. confident; that. the. materials contained asbestos. First, his former shipyard employment gave. hint.considerable; knowledge about tire, prevalence of asbestos in the gaskets and ;:packing used onboard naval ships! Second,;his background in;; characterizing shipyard sources of ashestos exposure gave him. tiieabilityt.o.y.is.iblydisti.ngti.ish.asbestos.-containingmat.eriai.s; from non-asbestos materials. Third, based on his .interactionswith various industries as a consultant, hewasawarepfwhich industries historically used asbestos packing tmd gaskets. The study conducted by the Navy in 19.78 and those conducted by - the first author, of this .article were-, the first to jtsbestos-containing gasket and. packing materials. It was. not . until 1.991 that the. first study on this issue was published. .in die.: peer-review literature/-1^ Since; then; a. number: of studies have evaluated exposures associated with removal and . installation. of-.asbestos-containing: gaskets. and. paching... materitils.^k"27) Direct comparison of .the results .from other studies to those describedin this pap.er.is. difficult given thatthe tasks evaluated, sampling and analytical methods, and overall study design are quite, different. For example, some, studies conducted short-term sampling/19,23~?-^ while others collected samples' over the course of an 8-hour:workdaydl-~22,2?) lit addition, different tasks.involved with removal.and installation J of gaskets .and packing were characterized by different stud ies. and not all: investigators .collected background, samples,.. particularly during .wprksiteZsmdi.es, to assess -..the. contri bution pf:environmental. cpatamiiiatiqn to..airborne: asbestos. measurements.,Z2::::::;;z::::::::::::zzz::::;::z:::::::: ..... With, a few; exceptions, the. resultsfirom the.series of tests, described in this, article, are; generally.-, consistent -with other gasket and packing studies.contlucied to date.(17>19"2k27) The . exceptions include the. studies conducted by Fowler efial/2^ i and Longo et al/'ri) In the Fowler study, asbestos .exposures : in - excess.: of- regulatory... s.tandards -were-, reported for tasks: involving bandsawing stock asbestos.sheet gaskets.:This type of activity was .not. commonly performed, and therefore was not an-.are-a of interest in the series of studies described in the: paper. Longo and colleagues reported asbestos concentrations in excess of'regulatory.levels dining the iciauval uf:. gaskets using. scrapers,, hand wire brushes,; and power wire brushes. This: data, contrasts the. data reported m ,tins, study, .as' well, as by other authors, including the Navy, Cheng and McDermott, Spencer, arid.Boolter et; al.fi7, It.is. not clear why. the; data reported in the Longo study, arc several times higher than; the values reported in the other studies; however, it has been noted that the. sample-filters were overloaded and that the work ; area was not decontaminated before each task (e.g., power wire brushing)/2-Due.to-.differences in sampling times and vagiie! study descriptions, it is unclear whether the short-term packing 8-hour TWA concentrations measured in this study. 96 Journal of Occupational and Environmental Hygiene... February 2006 Work site studies that do not report background airborne.. concentrations,, such -.as; those, conducted by the.Navy(n) iri.... 1978 anti Cheng and McDermott0^ in 1991, could easily overestimate the airborne asbestos exposures associated with handling ,of asbestcsrcontaiiiing gasket and packing materials..... Nonetheless, it can be conciudedirom the overallweight of the... rcsuLts from the studies conducted to dale that workers-dhectly. handling asbestos.packing aiid gasket;.materials,'.or working in an. area'.where, sudr products are being used, up until the:.. early 1980s. (when the use of non-asbestos materials, became, widespread) were not likely, to have been, exposed, to asbestos. levels in excess of the contemporaneous PELs.... In many industrial settings, particularly prior to the.. 1980s, the contribution , of., airborne. asbestos .from other sources, such as insulation, would have substantially overwhelmed any potential release from asbestos-containing gaskets and. packing.materials. As discussed earlier, gaskets and packing constitute: a small, fraction oftire,asbesto.s-.op.ntaining.materials:' used, on a ship. Historical exposure studies have . shown Utah exposure, during handling of insulation materials can be extremely, high.'.Airb.anie.'.asb.estos.ineas.ur.ements.,collected at."" British Naval shipyards, have shown average concentrations of 226 f/cc .(range 23-493 f/cc) during removal of sprayed, crocidolite asbestos, 15.2.. f/cc (range .7--89.6 I7c.c) during: removal of pipe lagging, and 9 f/cc (range 0.1-55 f/ee) during application of pipe.lagging. :Similarly, relatively, high exposures were doemnented among insulation workers in.IJ.S. naval shipyards. Nicho]son and colleagues^, reportedaverage airborne asbestos concentrations of 4.6 f/cc during -mixing) and .applying cement, insulation, 11,5 .f/cc. .during cutting and. applying blockInsulation, .and..67 fikewhile. spraying asbestos, fiber insulation. Intermittent peak exposures from, rip out pf. asbestos..insulations in machinery spaces (boiler, engine., and control.: roonvs) of ships, could measure in the hundreds of fibers/cc as measured .in the; 1960s,. An 8-hour TWA of 0.03 f/cc during tire disassembly of flanges. onboard a ship (wi.dt,fiange.face,cleaning).,'.Uie,highest.average concentration, measured in this study,, is. negligible compared to potential exposures.associated with direct handling of.insulation, mate- rial,or working in ..an:..?he.a:iiv w.Qrk,.is...being:. conducted... .. The. data from the .samples collected: during, all activities. associated with. asbestos: gasket .and .packing ..work ..indicate, that, the asbestos fibers released , during these activities are considerably lower, than .the. current 8-ho.ur TWA) permissible. exposure, limit of 0,1 f/cc,..let.alone.all previous.standards,/Both. the worker and bystander 8-hour exposures were.. extremely low, often below the limit of detection. The TEM data were, supportive, of.PCM. measurements, which is to be expected when sources of background contannuation of asbestos is elim,-. inated. The. dam front this study represent tlic actual airborne. ...asbestos exposureencountered by a worker or bystander..as gasket and packing replacement are performed. These data indicate that.asbestos. exposure to workers conducting removal and installation of tisbestos-containing gasket and. packing materials: is.beLowliisto.ri.caland.c.urrent.o.cc.up.at.ional.exposure limits for. asbestos and suggest that file,health risks associated: with.:these activities are negligible. ACKNOWLEDGMENT HPMs work was supported by Garlock, Inc., a gasket X )manufacturer.that.hasbeen involved in litigationregarding asbestos. Two of the authors (Car! Mangold and Dennis Pauster.bach) have testified as experts in cases involving asbestos. REFERENCES-------?---------------------- *................................ .l...KaraellA>rn, 3., and 3, Starr:..Historical perspectives, ou.asbcsio.s-.... Policies and protective- measures in- World War' II shipbulding. Am. J..... Bui. Med. ZT.359-373 (1987). " ; :; 2. United States Navy: Military Standards, Thermal.Insulation. Require:-;... .......merits, Bureau of. Ships Technical Manuals, .Mil-Std.-7t)9E, 1974,1975,: .3. Umted.Statcs.Navy: Chaptcr 39-Thcrrnul Insulation,; Bureau of .Ships Technical Maiiuals. 19.45, .1947,: 1967, 1972.,...................... ......... 4. Kelleher, IX, and. W. Bartlett: Asbestos packing and gaskets. Technical .......Association of the Eulp.mid.PaperIndustry. (TAP.P.I). .Engineering ,Co.aferr.; ........ence. Quezon City,.Philippines, 1983. ' 5, United States Navy: Burcau pf.Sliips. Scncs .of Plans, DD-3902, circa 1942-1943......... 6'.. .United States Navy:- Bureau of .Ships, Basic Set..of1-lull Machinery .& .Electrical Plans. DD-3902,1943. ....................................... 7. Plisko, M,: Asbestos Materials Summary for. Rktcher-Class Destroyer. BaitivoorerEnvironipwitat Profiles, Inc., .2002. pp,.l~4.. 8. Fleischer, W.E., F.J. Vlles, R.L. Gade, and P. Drinker: A health survey. ........of pipe covering operations in constructing naval vessels. /, Lnd. Hyg, .......: ToxicoL 6 (194.6).. 9. Occupational Safety and Health Administration: Tide 29-Labor, C'iiaptcr XVB. Part 1910-Occupational Safely and Health Standards, Standard for Exposure to Asbestos Dust. 371-11 11318-11322, 1972. 10. "National Emission Standards for Hazardous Air Pollutants; Asbestos :::..... Volume 55 'No. 24.; ' 11. Mangold, C.A., R.R. Beckett, and. DJ, Bcssmer: Asbestos Exposure and CoMroE-Puget.SoundNaval Sfcipyard.:13Iff)NAVYSfflPYDBREM ;...... P6260.1, (ll-70). Washingto.il, D.C.:.Department of.the Navy, 1970.. 12.. Mangold, ,C.A., R.R.: Beckett, and IXj. Bessmer; Asbestos Exposure ......... and Pulmonary X-rayChanges to. Pipe Coverers and Insulators at Puget Sound Naval Shipyard. Presented at the. American industrial Hygiene Association Mccting.at Richland,-Washington, .19.68, 13. Setikoff, L, and.D, Lee: TableQQ-l.. In Asbestos and Disease, D. Lce, E. . fiowson, and D. Okun (cds.). p, 466. New York: Academic.Press,' .1978. 14,;Liudell, TL: i Biological effects of asbestos,. In. Biological Effects of . Asbestos;.ProCeedings.ofa Working Conference,held at the International; .........Agencyfor Research on Cancer, P. Bpgo.vski, J, C. Gilson, Y. Timbrel!, .........:and J. Cr.Wagner, (cds.). Lyon, France:.Internati.ona.l Agency for. Research. ..on Cancer({AB.C), 1973. pp,323-3.28................... .......... ...15. Balzer,'.JX.,.and; W.C.,Cooper: The work .environnicnt.of- insulating: workers. Am. Ind. Hyg. Assoc. J. 29:222-^227 (1968).'. 16. Murphy, RX,, Jc, B.G, Tertis, Jr., W.A-. Burgess, J. Worcester, and E,A. Gaensjen.Effects of low. concentrations of asbestqs, Clinical,.. ..... . .environmental, radiologic and .epidemiologic observations in shipyard. .pipe coverers.and controls. N, Engl, J. Med 255;1271--.1278 (1971). 17. .Liukoneo,.L.R.,.K..R. Still, and.S-R. Beckett: Asbestos Exposure froni ..Gasket Operalions.Bre,merlon, Wash.; Naval.Regional.Medietd .Center, ..... ^Occupational &.Eavixonmcntal Health Service,. 1978.... 18. D'Agostino, R.B., Belanger A^ and R.B. D'Agostino Jr.;, A suggestion ZZZZ.Jfor' using! powerful and. informative, tests , of normality.. Am.. Statistician 44(4) 316321 (1990) ........................ Journal of Occupational and Environmental Hygiene February.2006. 97 19. Cheng,.R.T., and IIJ, McDermott;.Exposur^Jo asbestos.from asbestos gaskets. Appl, Occup. Environ. /fjy;,6:588-591 (1991). 20. Spencer, J.W.: Exposureassessment: <A^ Evaluation, of the Actual Contribution ofAi.rbowe Asbestos-Fibersfrom.tl.u; Removal.and Insloh.. lotion of Gaskets cind Packing Material. Project No. 8489.!' Baltimore: ......Eavironinenud.P.cofilcs, Inc., .19?s8,. 21. Spcncttvf ^.^l:fExp'psureK Assessment:'An Evaluation of the. Actual Contribution ofAirborneAsbestosFibersfrom the Fabrication ofGaskets.- Project No. 8500. Baltimocei Environtncnial Profiles, Inc., 1.998............... 22. Spence, S.K., and P,S. Rocclu: Exposure to asbestos, fibers during gasket removal. Ann..OCcupsHyg.,40:;|83.-588 (1996); ' ...... 23. Longo, W.E., iW.B^ Egelrmd^fcL. Iiatfield, aud.L.R, Newton: .Fiber- release during the removal of asbestos-containing gaskets:.A work practice simulation. Appl. Occup. Environ. Hyg. 17:55-62 (2002).. 24. MiUetle, J.R,, and M.D, Mount;-:A^study . determining: asbestos fiber release during die removal of valve paqkin)t,:Appl'T. Oa$up.. Envimri. Hyg.. 5:790-793 (1993):- - ^. v " A, :s 25. McKinnery. W.N., and. R.W. Moore: Evaluation of airborne asbestos ........ : fiber.lcvcls during removal and installation of. valve, gaskets and packing. Aw, M Hyg^Assac. >, .5:5:531-532 (1.992)5.... .26,.Fowler, D.B.; .Exposures to asbestos arising from bandsnwing. gasket;............ --'. material,Appl Occup. Environ. Hyg.. i5;4.04*4Q$.(2.000),. 27. Boeder, F,W.,. GJM.. Crawford, and(D,M. Po.d.raza: Airborne fiber:............ ......exposure assessment .of-dry asbestos-containing gaskets and packings.............. .... found in intact industrial and maritime fittings. Am. Ind, Hyg. Assoc. J.............. .......65:732-740 (2002). 28. Boeltcr, F.( G, Crawford,,and D.M-Podraza: Airborne fiber, exposure ....... assessment , of dry. asbes.to.srconlajn.ing gaskets and packings found in ........... ...... intact.Industrial and maritime fittings. Authors' reply,..Ant,. Ind, Hyg. Msac'l 64:595 (2QQ3)...................::..................................................: .29, Nicholson, WJ., D.A, Holaday, and EL lieunarm: Direct and indirect ..... .. occupational.exposure io. insulation dusts in. United States shipyards, .... In Safety and ..Health in Shipbuilding and .Ship..Repairing. Geneva: International Labor Office (ILO), 1972. pp. 37-47. ................... Journal of .Occupational and Environmental Hygiene:.... February 2006