Document r1KgnYxOJGQ67DmmX1VvLneJ

FILE NAME: Doubt Science (DBTS) DATE: 1995 DOC#: DBTS014 DOCUMENT DESCRIPTION: Journal Article from IJHS - The Origin and Development of the Asbestos Threshold Limit Value: Scientific Indifference and Corporate Influence HEALTH SERVICES INTERNATIONALJOURNAL OF hpeoalilttihcaalnedcosnoocimalypaonlidcysociology history and philosophy ethics and law editor-in-chief: Vicente navarro The OVroilgumine 2a5n, NdumDbeevr 4e--lop19m95ent of the ASscbieesnttoisfiTc hInredsihffoelrdeLncime aitnVdalue: Corporate Influence . David S. Egilman and AlexanderA. Reinert Baywood Publishing Company, Inc. 26 Austin Ave,, Amityvillc, NY 11701 cea-lml (a5i1l:6b) a6y9wMoo2d7@0 fbaaxyw(5o1o6d).c6o9m1-1w7e7b0 osirtde:erhltitnpe://(b8a0y0w) o6o3d8.-c7o8m19 Section on Science, Ideology, and Corporate Power THE ORIGIN AND DEVELOPMENT OF THE ASBESTOS THRESHOLD LIMIT VALUE: SCIENTIFIC INDIFFERENCE AND CORPORATE INFLUENCE David S. Egilman and Alexander A. Reinert Several recent articles have critiqued the process employed by the TAhmreesrhicoalnd CToimnfiet rVeanlcueeos.fCGroitviceirsnmmsehnatavleIinndculustdreiadliHnaydgeiqenuiasttesdinatdaectoelrlmecitniionng, inadequate research, excessive corporate influence, and slow response to idnefvoerlmopatmioennatl ochf atnhgeesA. mInertihciasnarCtiocnlefe, rtehneceauothforGsoavdedrnremsesntthale historical Industrial Hygienists' asbestos exposure guideline. They demonstrate that the proposed mifrfetinc was known to be inadequate when it was first proposed, was severely criticized between 1946 and 1968, but nonetheless was promulgated annually and remained unchanged until 1971. The American Conference of Governmental Industrial Hygienists (ACGIH) sets guidelines for occupational health called Threshold Limit Values (TLVs). These guidelines are relied on by OSHA (the Occupational Safety and Health ACrdimticiinsimstsraotifotnh)einguthideeUlinneit-esdetStitnagtespraoncdesssimhialvareapgoeinnctieeds taoropurnodbltehme swowriltdh. Pdaatsat collection, inadequate research, overwhelming dependence on data supplied by financially interested corporations, and slow response to advances m medical information (1, 2). An examination of the guideline-setting procedure for one occupational hazard in particular, asbestos exposure, reveals three fcctoratfaat have influenced the determination of many other ACGIH guidelines, (a) ACGIH failed to analyze previously published literature, orreview and incorporatecurrent literature (inadequate research); (b) ACGIH uncritically accepted unpubbshed research date from financially interested companies (poor judgment); (c) finan cthiaelilryIninsuterreersst)emdocdoimfipedanmieesdi(caasbl aersttiocslems atonumfiancitmuriiznegcaonndcemrninoivnegrcaosbmepsatoresh!eaalntdh International Journal of Health Services. Volume 35, No. 4, Pages 667-696,1995 1995, Bsywood Publishing Co., lnc. 667 668 / Egilman and Reinert ^ r J s s r M S t s from 194610 1971, despite overwhelming evidence o f inadequacy (3). The com bininhaatrimonfuolfeixnpadoesuqrueasteorfeassebaersctho,sptooomrjiulldiognmseonftw, aonrdkecrosrwpoorraldtewide. OtherACGIH W2 e rSaise othfeiacsobuensttoabs ietxitaym, pwlehiicnhohrdaesrrteosuploteindt atondAwCiGllIHressugltemnertahletnpudb^hrecanucoen numerora guidelines that may ultimately fail to protect the pubhc from ^,,Spu*l =cnwe ,nund. Ui. . is JTM * * ^ 3 ^ 0*so i m " " * AC? T ^ S T m " S S S S k * . urn OfC . - I ta M I Limit W . W sad "Maximum Allowable O w cM m O J* ^ JJW ^ Sold ^ S S -sS T iS rssi " bdeitfidnieddnaaoTTticLVhVanaasgseaanthnaeavdveeerfariagngeiteiaonndoaf mtheaxgiumiduemlinleesvsuefrlocrtthoattosxhiocosubsta^nceCsX,^as<seJe.n Different definitions imply different total exposure w w in Figure 1. ASBESTOS: PHYSICAL PROPERTIES - sssrssriffissri cchoemmbiicnaalticoonmopfossiitliiocna, (oitxyisgean,siuancda m>agnesium or i.ron, Boeefore asbestos >was Histoiy of the Asbestos TLV / 669 Max. Max. Max. Avg. Maximum Maximum Average and Average Figure 1. Different definitions of the Threshold lim it Value imply different total exposures widely identified aa a disco causing dust, exposure to silica dust was recognized ansattuhreecaoufseasobfeastroesspiisratthoery pdhisyesaicsealthcahtabreaccatemriestkicnotwhantasdiSsitUincgoussiss.h*eTsheafsibbersotuoss ^In* evaluating the guideline applied to asbestos exposure, it is important to consider the distinction between the fibrous morphology of asbestos and tire nthoantf,ibwrohuens nvaiteuwreedofuonthdeerrdausmtsi.cFroosrceoxpaem, preles,esmilbiclea dduostts.isAcosbmepstoossedduosftp, aomnctlhees other hand, is made up of particles and Fibers, elongated particles with p arcel edges and apparently equidimensional cross-sections (4). Fibers, as a subset of particles, are defined by some as particles with a length three times greater than their width (5). 670 / Egilman and Reinen In addition, notwithstanding its fibrous nature, asbestos can never be found as pure fiber. Where it is mined, it is mixed with dirt, rocks, and grit, which microscopically are particles. Even though the process of carding and purifying asbestos removes much of the foreign particles, asbestos itself can chip and flake and produce particles. Because of this, even 100 percent fibrous asbestos (for example, in asbestos cloth) will, if ripped, tom, or cut, produce other particles in addition to fibers. Therefore, any time asbestos is used, even in relatively pure fibrous form, there are exposures to both fibers and particles. This can confound attEemvepntswtohemneaassbuersetoesxpeoxspuorseu.re is assessed by a measurement of fibers instead of all particles (which includes both particles and fibers), the process is complicated by the physical propensity of asbestos to fracture longitudinally, causing a single fiber to produce many fibers; this division can occur in the lung after inhalation (6). The process of in vivo breakdown has not been well studied either in animals or in hum ans. It further obscures the assessment of exposures even when fibers themselves are measured. HEALTH EFFECTS In a case study reported in 1907, Montague Murray was the first to note the adverse health effects related to working with asbestos (7). Originally labeled "asbestos poisoning" and later termed "asbestosis," the symptoms associated with the disease included dyspnea, cough, emaciation, weakness, and chest pain. Cooke (8) and McDonald (9) were the first to describe "curious bodies" m the lungs of individuals who had died of asbestosis; these bodies were later called "aBsbeecsatoussiestbhoedideiss.e"ase asbestosis was identified soon after the United States .naa, begun to grapple with silicosis, analogies were drawn between the two diseases. Clinically, asbestosis is a much more serious disease: ithas a shorter time of onset, the symptoms are more severe, and the average life span of an asbestotic is much shorter than that of the average worker who dies from silicosis (10-14). X-ray Changes in silicosis arc much more dramatic than those in asbestosis. Clinically, however, an asbestotic with less marked X-ray abnormalities may be more severely disabled (15-17). Mechanism o fDisease Production In the 1920s and early 1930s, Leroy Gardner, the director of the Saranac Laboratory, conducted experiments to explain the health effects of asbestos (18, 19). Gardner's experiments were designed to determine whether the chemical ceoffmecptossoitfioinnhoalfinthgea asbestos sbestos-c or on its tain fibrous ing dus n t. ature Gard was ner's the cau studies se w of ere the fun dheadrmbyfua group of asbestos companies who maintained control of the content of the final History of the Asbestos TLV / 671 publication (1). He exposed animals to combinations of asbestos fibers ofdifferent lengths, and to particles. To test the effects of pure silicate chemical exposure, animals were exposed to ground asbestos (ball-milled asbestos), composed almost penrotidruelcye oafdpuasrttticoletes.stTthhee rpoulerpoofsethoefcthheemgircianldcionmg pwoassititoondienstprrooyduthceinfgibdeirsseaasned. The results of the Gardner studies, and most subsequent studies, indicated that the pathogenic property of asbestos is due in large part to its fibrous composition and shape rather than its chemical composition (20). Carcinogenic Properties o fAsbestos In 1935, Lynch and Smith (21) reported the first case of carcinoma of the lung in a patient with asbestosis. Throughout the late 1930s and early 1940s, other articles were published discussing the occurrence of lung cancer in asbestotics (22-24). In 1941, Nordmann and Sorge (25) published the results of their animal experiments that resulted in the production of pulmonary cancer in 20 percent of the animals who survived the inhalation of asbestos. By 1949, the association between asbestosis and lung cancer had been firmly established and was the subject of an editorial published in the Journal o fthe American MedicalAssocia tion (26). Further evidence of the carcinogenic potential of asbestos was provided by Doll's (27) large-scale epidemiological study in 1955 wherein he estimated the risk of lung cancer in asbestos workers to be 10 times that in the average individual ANDOORTIHGEINR GOUFITDHEELIANSEBSE:SSTUORSVGEUYIDAENLDINAEDOPT Once asbestos was recognized as a hazardous agent, a guideline for excess asbestos exposure was explored in an attempt to protect the tens of thousands of workers in the United States who were being exposed. The first value for the asbestos guideline for dust control arose by analogy to silica (28). The silica guideline was based on engineering feasibility, not on the prevention of adverse health effects (29). The adequacy of the proposed asbestos guidelines was fust challenged in 1935. Clark and Drinker (30), relying on unpublished Metropolitan Lthiafet Mstuedtrioesp,oilnitdaincaLteifdeth"patrethfeerssatfoe esexepothsuerdeulismt citofuonrtabsebleoswtos5wmaisllnioont k(npopwcfn),abnudt welcomes still lower figures." Unaware of the unpublished Metropolitan Life data, in 1938 the U.S. Public Health Service proposed a tentative Maximum Allowable Concentration for asbestos of five million particles per cubic foot (5 mppcf) (31). One of the authors of this study recognized the inadequacy of the pwraosponsoednagtuioidneallinsteainndaarsde-csoenttdin1g9p3r8opcuesbslitcoatiinocno(r3p2o)ra(steeethbeelporwo)p.oBseyd1g9u3i8d,etlhienree, however inadequate, into an enforceable occupational standard. 672 / Egilman and Reinert In 1938, the National Conference of Governmental Industrial Hygienists (NCGIH), a precursor to ACGIH, was formed. Composed entirely of volunteer industrial hygienists who were self-appointed creators of safety guidelines, its goal was to promote industrial hygiene and sanitation (33, 34). In 1942, NCGIH began to develop a list of proposed guidelines for different substances, including asbestos (35). Without any review of research or data, the Subcommittee on Threshold Limits of NCGIH presented a table of "Maximum Permissible Con centrations" for various hazardous atmospheric contaminants (35). The principal source for the table was a survey of various state industrial health units. The value of 5 mppcf for asbestos had been accepted by at least seven states, while one state used a MAC of 15 mppcf. Some of these states used values from a list furnished by the U.S. Public Health Service, which stated that its own values were "not applicable in light of present knowledge." The Subcommittee recognized the inadequacy of all the data when they wrote, "The table is not to be construed as recom m ended safe concentrations" (35). In 1946, despite this recognition ofinadequacy, NCGIH, now renamed ACGIH, adopted most of the values in the table from the 1942 meeting, including the Lasibmeiststosstvaateludetohfat5 "mvpalpucefs(3h6a)v.eDbr.eFenredceormicpkiloefdthfreoSmubtchoemlmistittreeepoornteTdhbreyshtohlids sub-committee at the 5th annual meeting of NCGIH in 1942, from the list pub lished by Wanen Cook in Industrial Medicine, vol. 14, p. 936,1945, and from published values of the Z-37 committee of the American Standards Association." In 1945, Warren Cook's (37) list was based on consultations with various indus ptrrioavl ihdyegdiemniisntismcaolndcoecrunminegntthaetiognuifdoerlimneosstthoafthwiseprerobpeoisnegdugsueiddealtinthees.tiMmoe.teCtohoakn 70 percent of the guidelines were based solely on acute toxicity studies rather than studies to determine chronic health effects. ACGIH never reviewed literature or conducted any other studies of the protection afforded by these numbers. No research was done between 1942 and 1946 that might have convinced the Com mittee to accept the 5 mppcf value for asbestos. The Threshold Limits Committee did not investigate or evaluate--it surveyed and adopted. This set the pattern for the next three decades of A CGIH-published guidelines. DEFINING THE PROBLEM: PROBLEMS WITH DEFINITION The fundamental problem with ACGlH's policy of "survey and adopt," aside from its implication for the reliability of the guidelines, is that it never defined the parameters of the asbestos guideline. Instead, ACGIH merely recorded that the guideline for asbestos was 5 mppcfofair. ACGlH's failure to define the guideline raepspullitceadbiilnitay mofyoritahderogfuqiudeeslitnioens)s: cDoindcethrneingguiidtselainpeplpiecratbaiilnityto(a5nmd,iltlhioenrepfoarreti,ctlhees of dust containing a small amount ofasbestosor 5 million asbestos fibers?Was the History of the Asbestos TLV / 673 proposed value an averageora maximum level that should notbe exceeded?What level ofprotectiondidtheguideline provide (short-term iintation, chronic disease, or cancer)? What was the safety factor? Each of these issues is discussed more fully below. ' Total Dust Containing (Some)Asbestos versus 100 PercentAsbestos Fiber Dreessen and workers' (31) 1938 U.S. Public Health Service (USPHS) study ogufitdweolinaes.beInstothsattesxttuildeyp, lDanretsesisneNn osurtghgCesatreodlianatefnotramtievde dthaenbgaesrilsevoeflthoef 55 mmppppccff tboeraecdcuucmeutlhaeterdis(k31o)f. Easvbeenstaosciusrasomroynrgevaisebwesotofsthweosrtukderysruenvteiallbsetthtaetr Ddaretaescsoeunl'ds tentative danger level was a measure of total dust (fibers and dust particles), where the average asbestos and cotton fiber content ofthe dust was only 9 percent (TTabhleef1a)c.t that USPHS's tentative level was intended tobe a measure oftotal dust that contained asbestos fiber is supported by the technology available at the time ospfetchieficsatulldyym. Eeaxscuerpetfoibnerancoenxcpeenrtirmateionntailnbaaisrisu,nntiol ttheechlantoelo1g9y60ws.aTshaeviamilpaibnlgeetro, developed in the late 1930s, was the measurement device most commonly employed by the U.S. industrial hygiene community until the late 1960s, and was at times prescribed by ACGIH for the measurement of mineral dust expo sures. An impinger sampling did not distinguish between fibers and particles of other shapes (38). . Table 1 Composition of dust in textile mills studied by Dreessen and coworkers (31) 1938 Activity Percent asbestos and cotton Weaving" Weaving* 26 12 Picking" Carding" 8 7 Twisting4 5 Twisting* Crushing" 5 1 Average 9" *PBlaannttBA.. `Notin original. 674 / Egilman and Reinert Further support for the interpretation that the guideline was a total dust standard is furnished by the 1946study of Fleischer, Drinker(a memberof the first ACGIH TLV committee), and colleagues (39), which contained the only definition of the guideline published between 1946 and 1962. In their paper the asbestos guideline waFsidnaelfliyn,eidna1s9a68to,tAalCdGuIsHt sitmanpdoasredd. a unique restriction on the use of the asbestos guideline which indicates that it believed the guideline to be applicable to total dust. In 1968, ACGIH repotted that the guideline for mixtures containing asbestos should not be raised even when there is a reduction of the asbestos percentage in the dust due to an admixture with other nontoxic substances (40). Therefore, even if the percentage of asbestos in dust generated from a source decreased because of the mixture of nonlethal dusts, the guideline remained at 5 mppef. By recognizing that any amount of asbestos in a dustjustified the implementation of the 5 mppef guideline, ACGIH recognized that the asbestos guideline was a total dust standard. Maximum versus Average The Subcommittee on Threshold lim its that created ACGIH's proposed 1946 guidelines termed them "Maximum Allowable Concentrations" (36). ACGIH, however, did not explicitly define this term until 1953 (41). The values could have been interpreted as a maximum average level, a maximum level, or both, but ACGIH did not identify which guideline belonged with which definition (36). In facDt,edsipfifteereAnCt dGeIfHin'istiofanisluarpeptloiesdpteocdifiifcfaelrleyndt egfuiindeeltihneesl.evel of permissible expo sure, a letter written by Philip Drinker (42) reporting on asbestos dust levels created aboard ships by insulators and other asbestos product users supported the interpretation that the asbestos guideline represented a maximum level not to be exceeded. Drinker, Head of Industrial Hygiene at Harvard University and con smuiltttaenet, twortohtee Uth.aSt."NDauvsyt caonudn, tassinnottheedraoboomvew, haemreetmhebemr eonf twheerefirwstoTrkLinVg cwoemre very much higher than anyone would recommend--they ran up to 25 million. A figure of 5 million for asbestos is recommended." Obviously a single exposure above 25 million for a short time (20 minutes to an hour) would still leave one well below the average, 5 mppef for a whole day. Therefore it is clear that Dnnker interpreted the asbestos guideline as a maximum level not to be exceeded. In 1948, ACGIH changed the name of the guidelines from "Maximum Allow able Atmospheric Concentrations" to "Threshold Limit Values" (43). Not until 1953 did ACGIH provide, forthe first time, a preface to explain how the numbers wvaelrueestonobtetuosbeed e(x4c1e)e. dTehde. Tvahleuepsrewfaecreeodpeefninsebdyadsebsocrtihbianvgerdaigeevsaalunedsmasax"immauxmi mum average atmospheric concentrations" and ends with "It is felt, at the present History of the Asbestos TLV / 675 time, that workers should not be exposed to a working environment containing any of these substances in excess of the value indicated." The research community also interpreted the guideline as a maximum value not to be exceeded, in part because it was acknowledged that peak exposures for Intermittent periods could be more harmful than low average exposures for long periods of time. In 1953, McLaughlin wrote (44): The concentration of dust which can be inhaled without danger varies accord ing to the nature of the dust and also to the length of time that a man is breathing it Again, the intermittent exposure to high concentrations of dust may be more dangerous than exposure to lower concentrations over a longer period. ACInGI1H96e1x,plAaiCnGedIHthaatrbthiteravraillyuersendoewfinreedprtehseesnetedgu"itdimelien-ewseifgohrtead saevceornagdetcimone. centrations" which "may be exceeded for short periods" depending upon a number of factors such as the nature of the contaminant, whether very high concentrations etivveen, tfhoerfsrehqourtenpceyriowdisthpwrohdiucchehaigchutceopnoceisnotnraintigo,nws ohcecthuer,ratnhde tehfefedcutsraatiroencoumf suulcah periods (45). Under most circumstances, averaging exposure levels in this manner results in an increase in total exposure to the toxic substance (Figure 1). ACGIH did not offer any justification for the resulting increase in permissible exposures toNmootswtistuhbsstatanndcinesg. ACGIH's newly created application of the guidelines as "time-weighted average concentrations," the guideline for asbestos remained a maximum level not to be exceeded. At the 1967 meeting of ACGIH, British industrial hygienist S. A. Roach specified the mannerby which dust counts should be conducted and interpreted to maintain compliance with the ACGIH guideline. He maintained that the ACGIH guideline should be interpreted such that excur sions above any limit should not last more than 15 minutes (46). The "test TLV factor" specified how much a 15-minute excursion could safely exceed the TLV. Roach noted that ACGIH had not yet determined a "test TLV factor for mineral dusts (46). Therefore, without a safe excursion level for mineral dust, the guideline for asbestos could only be interpreted as a maximum limit not to be exWceehdeend. sampling for compliance with the ACGIH guidelines, industrial hygienists typically gathered fourto eight samples of 10to 15 minuteseach during an 8-hour shift. Noncompliance with the guideline would result if any single sample was above the guideline value. Accordingly, the guideline was viewed as a "speed limit," a number that should not be exceeded and above which values could not, with impunity, be averaged with low values or hours off thejob. Throughout the entire process of shifting definitions and terms, the absolute value for the asbestos guideline remained at 5 mppef. ACGIH did not review or 676 / Egilman and Reinert conduct any new studies on the adequacy of the guideline to determine whether, under the various definitions, S mppcf protected against asbestosis. Level o fProtection In discussing the level of protection offered by the guidelines, Manfred Bowditch remarked at the 1943 NCGIH meeting (48): Whatyou mean by toxic seems to me relatively unimportant to the discussion. We don't talk about toxic limits in our standard. We simply say that there are maximum allowable concentrations. We don't even say why they are maxi mum or why they are allowable. Obviously, Bowditch did not have a clear understanding of the meaning of "maximum allowable concentrations." His accurate assessment of the confusion surrounding M ACs was com pounded by A CG IH 's failure to define the guidelines and the level of protection accorded by compliance with those guidelines. By 1946, the Subcommittee on Threshold Limits had identified three possible levels of protection (36): 1. Just Escape Health Effect One concept is that the M.A.C. value should represent as accurately as possible that concentration at which a worker exposed for a sufficient period of time will just escape physiological or organic injury and occupational disease. 2. Provide a Margin o fSafety A second concept is that the M.A.C. should represent some fraction of that concentration which will injure the workerin orderto allow a margin of safety in the design of protective equipment and guard against possible synergistic effects in the case of multiple exposures. 3. Provide a Margin o fSafety and ProtectAgainst Irritants A third concept is that the M.A.C. should perform the functions of the former concepts and in addition provide a work environment free of objectionable but non-injurious concentrations of smokes, dusts, irritants and odors. Each of these possible interpretations requires a different analysis and computa tion and should result in a different guideline value. Unfortunately, in 1946, when AguCidGeIlHinefsirstht aptuabplipslhieedd ittos laismt oufltgituuiddeeloinfessu, bitstmanecreelsy, awdiothpoteudt aanwyiddeefvinairtiieotny oorf discussion of what level of safety the numbers were intended to ensure (36). In History of the Asbestos TLV / 677 1947, the Committee finally selected a definition for the protection level of the guidelines, a definition that had not even been proposed earlier (49). The defini tion selected was proposed by L. T. Fairhall and defined as "that amount of gas, ivmappoairr,mfuemnteOofrbdoudsitlywfhuinchctcioann,beeitthoelreirmatmedbdyiamteaonr wafittehrnyoeabrosdoilfyexdpisocsoumref,o"rt nor Contrary to customary practice, ACGIH selected the numbers first, and then later defined the level of protection offered by these numbers. Furthermore, while the definition that ACGIH finally adopted indicated that adherence to the guidelines would protect against chronic exposure, most of the numbers were based on short-term human or animal studies. ACGIH did not conduct any investigation to guarantee that the guidelines complied with the level of protection as the Conference defined it. ACGIH merely picked a definition without any examination or study. In addition, after selecting a definition, ACGIH never tciloanri.fieIdn wthheactawseasomf tehaentasbbye"stboosdgiluyiddeislicnoem, tfhoirst''isopr a"ritmicpualairrmlyensitgonfifbicoadnilty, sfiunncce, ausntwile19w7i1ll(d5e0t)a.il below, ACGIH ignored the carcinogenic potential of asbestos The effect of these unclear and changing definitions on any attempt to provide a safe working environment could only have been negative. ACGIH's publica tions provided numbers with no meaning. On the one hand, the scientific basis for the guidelines was questionable. On the other, given that there was no clear understanding of how they were to be used, application of the guidelines could vary with the whims of the industrial hygienist. In the end, as we discuss below, mthienainsbgecsotomspgauniidees.liTnheiws saistugaetnioenramllyigihgtnhoarveedbbeyesnhaimpbeuliioldreartes,dmquanicukflayc,tuifrAerCs,GaInHd had had an adequate review process. Unfortunately, this was never in evidence. REVIEW PROCESS In 1953 and 1961, ACGIH stated that the proposed values were to be "reviewed annually by the Committee on Threshold Limits for changes, revisions or addi tions" (41,45). The first documentation of the guidelines, however, took 7 years to produce. According to Herbert Stokinger (51), chairman of the TLV Committee in the 1960s, the 300 or so TLVs "were farmed out in numbers and subject according to the 6 members' intimate knowledge and familiarity with the sub wstaenreceb.a"sTedhiosnrespvaierwsepscroiecnetsisfiwc carsitteimriae.-consuming in part because the guidelines Although ACGIH claimed to conduct an annual review of the various proposed guidelines, between 1953 and 1961 no annual rvaluation of the guidelines occurred, since the first documentation of the guidelines was not complete until 1962. Furthermore, even after the documentation was produced, there is no evidence that ACGIH ever regularly conducted an annual evaluation of the exist ing guidelines. A review of the Transactions o f the Annual Meetings o f the 678 / Egilman and Reincrt ACGJH that there was rarely any mention of the evaluation of current values, there was no mention of cunent research being conducted on various substances, and there was no critical examination of research that had already b eWenhceonn dthuec tveadl u(e3s, 3w5e,r3e6d,i4s 0,4 cus 1,4 sed 3a t , 4A5C,4G6IH,4 8m-e5e0t i,n5g2s-, 7a1s )i.n t h e c a s e o f si l i c a i n 1962, the general inadequacy of the mineral dust guidelines was dramatically demonstrated in this discussion by Ashe (63): BVuertmleotnmt, ehabprpinengsotuotbtehiensNpeewcifYicorcka,saenodfhaanppienndsutsotrbyetohuattoisfbvuesiiynecslsosneowto. Iwtawsesnlattoen, mfoarkainlgonsglattiemger.inAdnedrst.hAenmdatthearitaslltahteathtahdetihnidrtuys-tfriyvewpaesrpcuelnvteqriuzairntgz /a] ntuhwrernshtohledslaimmietqoufatrwtzecnotyntmenitllaiosngrdaunsittep,aarntdicltehsepexerisctiunbgicfefeoliontgowf aasir(wthaast aitcecveepntatboletw, aenndtyt.hAatnidndwuesthrayvaecacespanteidtotrhiuatm,atnhdatthheaysmfoaungyhmtleiknewhheollhtoavreedduiecde ox-frsaiylicfialetufbuellrcoufloxs-irsaybsecoafumseenofwahnoMarAe.dCe.atdhathtawtawsillloporhoivgeht.w. .e.ntIyhmavilelioann particles ofgraniteper cubicfootofairis toomuch forthemtoliveandwork. It should have come as no surprise to ACGIH that the silica standard proved ineffective. As we have already pointed out, the standard for silica exposure was initially based on engineering feasibility, not health considerations (29). ACGIH s failure to review the silica standard adequately was duplicated m the case odofcausmbeesnttoast.ioAnlcthoonucgehrnitnhge tahsebegsutoidselginueidewliansenwotaspraoddoupcteedd uinntil1914966,1.thme fiarast documentation, ACGIH belatedly recognized that the guideline measured the wrong thing (45): Wthohsieleocfhseemttliecdaldaunsatlsyasmispolefsc,oiltleisctbeedliseavmedpldeisalodfuasirtbcoorunnetsduosftpcaortrirceuslpaotensdbtyo criosnkvoefnatisobneasltomsiesthboedcsaucsaenobfetehxepgercetaetdretolagtiivvee iomnlpyoartnanincdeiorefcltomngeafisbuerres.of the Thus, although the animal and human studies forming the basis of the asbestos guideline were based on particle samples, the disease was thought to result mainly from exposure to the asbestos fiber component of the dust ACGIH's realization of this fact is not surprising since the asbestos guideline had been criticized on this baDsisesipnit1e95th8e(7r2e)c.ognition that the asbestos fibers were the cu.lp.rit. in causing Hi**., ACGIH continued to recommend a guideline based on the measurement oanfytootaflUpsaTrtLicVulbatoeomklaetttsecr,ofmaimleednttoonalttheer tihmepraecctotmhamtesnudchedknvaolwuele,dagnedhduidd onnotthme adequacy of the particulate-based guideline. History of the Asbestos TLV / 679 An inspection of the Transactions of ACGIH indicates that the asbestos TLV was only reviewed in 1968 (40). At this time, it was recommended that the TLV for asbestos be adjusted downward to 2 mppcfor 10 fibers/ml (40). A typographic error, however, resulted in the recommendation being printed as 12 fibers/ml. This error, although acknowledged in the annual meeting of the ACGIH, was never corrected, and the TLV for asbestos was published as 12 fibers/ml for 3 years. In addition to lowering the recommended level of exposure, ACGIH noted in the 1968 Documentation of the TLVs that the new asbestos guideline was only designed to protect workers "exposed for thirty years, a period rarely exceeded in America" (40). All other standards apparently continued to apply to a 40- or 50-year full working life of exposure to toxic substances. Workers exposed to asbestos were dying before they could complete the usual working life span, both because exposures were exceeding the guideline and because the guideline itself was insufficient to protect workers from cancer and asbestosis. The ACGIH review process was virtually nonexistent. Although it stated it would annually review the proposed guidelines, in reality, ACGIH merely accepted and adopted numbers without any detailed evaluation of their scientific bevaseins.toAuftpedrattheevnaulumebsetrosrwefelerectamdoopretecdu, rAreCnGt kIHnofwalieleddgeto. Icnognednuecrtaal,ntyhestluodnigeseroar ' TLV had been on the books, the more outdated its basis was likely to be. The importance of such a critical review is evident in the consideration of two issues: the adequacy of the scientific foundation for the proposed asbestos guideline l(iDnerefeosrseinns'uslUatSioPnHwSosrtkuedrys.published in 1938) and the applicability of the guide What a CriticalAnalysis o fthe Asbestos Guideline Would Have Revealed to ACGIH in 1946 As noted earlier, Dreessen's USPHS 1938 study examining asbestos-containing dust in a textile plant in North Carolina formed the scientific basis for the 5 mppcf raesvbieeswtoesd tghuisidsetluidnye purilotirmtoataedlyopatidnogpttheed5bmyppAcCfgGuIiHde. liHneadforAasCbGesItHos,cirtiwticoaulllyd have determined that the guideline was inadequate. It is important to note that the inadequacies of the study were obvious and known to the authors (Sayers and Lanza) at the time (32). As noted by Sayers in 1938, a "fifth of those with an exposure of 50,000,000 to 99,000,000 particle years and one half of those with more than 100,000,000 particle years, had asbestosis." If a workerwas exposed to Drecssen's proposed standard for 40 years of working life, he or she would have accumulated 200,000,000 particle years of exposure. Similarly, in 1964 Lynn Schall (73), Chairman of ACGIH in 1963, emphasized major shortcomings in the scientific basis for the asbestos guideline. Although ACGIH was capable of making the same critical analysis before and/or after Schall's critique of Dreessen's study was published, it never commented on the 680 / Egilman and Reinert inadequacy of the basis of its asbestos guideline. Listed below are some of the essential limitations of Dreessen's proposed tentative guideline, which ACGIH would have discovered had it undertaken a critical review of Dreessen's work. 1. Because of a relatively young workforce, only 20 percent of the workers in his study were exposed to more than onc-halfthe proposed guideline (200 million particle years total exposure over the course of a person's lifetime). In fact, asbestos-induced disease was noted in workers who had worked in the plants studied for up to 10 years, and who were exposed to dust levels between 2.5 and 5 mppef. In addition, 50 percent of workers exposed to more than one-half the MAC (lifetime dose) had asbestosis. Furthermore, Dreessen referenced a similar study done in 1934 which found that 8 percent of workers exposed to average levels of 4.64 mppef were found to have developed asbestosis (74). 2. Dreessen emphasized the fact that a very small percentage of the dust that he wreacsormdeedasthuer ing per con cent tain age ed of asbestos. (asbestos aAnds noted cotton) abov fiber e, a t al le l s d s t u h st an counts 13 perc but ent. o T n h e e average percentage of fibers was 9 percent (Table -1). The techniques used by Dreessen did not allow differentiation between cotton and asbestos fibers. D"Nreoesssaetnis.faTchtoerryefoterceh, ntihqeueascboeusltdosbfeibdeervelelovpelesd wfoerretheivsepnurlpoowseer,"thaacncotrhdeintgottaol percent fiber presented. Given this, even ifone were to accept the adequacy of the 5 mppef level of total dust, a proper interpretation of Dreessen's data showed that pure asbestos fiber exposures over 450,000 fibers per cubic foot caused disease (9 percent multiplied by 5 million total particles per cubic foot = 450,000 fibers pe3r.cuDbriecefsosoetn).and others studying textile mill exposures looked at a relatively constant exposure level. The processes of milling, spinning, and carding asbestos went on continuously in a particular location within the mill and could be con stantly ventilated. This is to be contrasted with much more variable asbestos dust exposures for product users, particularly insulators, but also for other workers using asbestos in relatively uncontrolled conditions. In these conditions, asbestos exposures as high as 1191 fibers/ml have been noted (scores higher than the equivalent previous total dust guideline) (75). Since Dreessen examined con tinuous exposures, the tentative value he recommended represented a maximum allowable concentration and an average. 4. Lynn Schall, commenting on the composition of workers in the USPHS study, made these points (73): About 15 months before this study was begun, approximately 150 workers in these asbestos textile factories were replaced by workers with little or no previous exposure (p. 46). Although an effort was made to examine as many as possible of these formerworkers, a majority could not be examined. Partly as a result of these personnel changes, the group of employees examined in this study had an unusually low average age. There was an abnormally large History of the Asbestos TLV / 681 P ^ m a p . of workers with less than five years' employment in the asbestos textile industry and an abnoimally small percentage of persons who had worked 10 years or more in this industry. . . . The book Silicosis and Asbestosis by Lanza states on page 173 "In some roentgenograms of asbestos factory workers seen with Dr. 1.anza, we noted that there was a direct progres sion into a terminal diffuse fibrosis without any nodular predominance. This terminal state seemed to have been reached in about 20 years on the average. On page 186 we find "Merewether and Price state that, with continued exposure to high concentration dust, fibrosis may be fully developed in from seven to nine years, and that death may result in about 13 years. With less concentration, fibrosis may not be fully developed for 15, 20, or 25 years." Yet, in this study 333 of 511 employees have worked for less than five years! f r oImn evalu a crit atin ical gretvhieeswe loimf Ditracticosnsse,n A 's CG stu IH dy tchoaut ld sh h o ave uld gle hav aned e bee severa n cons l i key dere p d poirniotsr to the blind acceptance of the 5 mppcf guideline: 1. T he tentative guideline applied to dust containing less than 13 percent asbestos and thus represented the concentration of total dust that contained a small 2. Tpherec5enmtapgpecoffvaaslbueestwosasfinboert.a valid time-weighted average guideline because half of the workers exposed to more than half of the guideline (equivalent to 3.. s2i0ncyeeaDrsreoefswseonrekxaatm5imnepdpccofnatvineuraogueseexxppoossuurree)s,dtehveeltoenpetadtiavsebvesatlouseish.e recom mended represented both a maximum allowable concentration and an average concentration. ACGIH, however, did not critically examine Dreessen's paper. Instead, con fusion and indifference abounded, and in 1962, 24 years after USPHS published its study, exchanges such as the following took place at die annual ACGIH meeting (63): Mr. Kcppler. 1have never been able to get clarification what is meant by that five million [mppcf], whether it is asbestos that is present? Is that the limit, or is that predicated on the percent of asbestos? Mr. Ashe: I think you brought up a question the committee needs to study. I think asbestos is one of the things that really needs to be investigated. There is no answer to your question. I know what you mean. I have been in asbestos plants where it was really dusty. You would swear it was a hundred [100 mppcf], and you lake a sample and only get a count of five [mppcf]. As far as I could see the value of five was decided upon because that is the most anybody could ever come up with. 682 / Egilman and Reinert Thirty years after the USPHS study was published, ACGIH acknowledged criticism of the 5 mppcf guideline (40): Avecryonrfeearlenpcreoboanbtihlietybitohlaotgitcheef5fecmtspopfcafslbimesittosreicno1m9m65ecnadleleddbaytteDnrteioenssteonthies iansabdeestqousa.tMe teodgicivaledcaommpolnetwehwicohridthneg-lliimfei-ttsimhaedpbroeteenctbioasneadgwaienrset ianlladfoerqmuastoe;f mthuosreptrhoavnidheadlfaonftihnseuafsfbiceisetnotsewxoprokseurrsesttiumdeiefdowr aesrebeusntodseirs3t0oydeeavresloopf.agOefatnhde o1n0l5yw4ohrkader>s1e0xpyoesaerds etoxp<o5sumrep.pScfe,v8e2nhoafd3w6 owrokrekde<rs5eyxepaorsse;d1t0o1,5<-91.09yyeeaarrss; hasabdeastsobseisst.oMsiso;re3oovfe5r,0itwworakseras"epxopionste-idn-ttoim1e0"-1s9tu.9dym; pmpacnfyfoorf<t5heyeiallrswhearde missing and the dead uncounted, hence not considered in the over-all evalua tion ofthelimit The TLVfor Insulation Workers In addition to the qualifications on the asbestos guideline inherent to the Dreessen study, a review of the literature by ACGIH would have revealed other limitations to application ofthe asbestos guideline, especially in relation to insula tion workers. In 1946, when ACGIH first adopted the values from the 1942 table opufbthlieshSeudbcaomStmudiytteoefoansTbehsrteosshoplidpeLciomvietsrinogf NoCpeGraIHtio,nFsleaisbcohaerrdannadvoatlhevresss(e3l9s). Because of the varied nature of the work and the inability to continuously monitor excess exposure, Fleischer and coworkers recognized that the TLV could not be relied on to protect insulation workers. They realized that shipyard exposures involved peak and average exposures that exceeded the guideline, and stated that, "in view of the varied character of the environmental dust exposure in the pipe covering industry on naval vessels, it is manifestly impossible to set a threshold" (39; emphasis added). As a result they made a series of recom mendations designed to protect insulation workers from insulation-induced health effAectsstu(dTyabblye 2M).arr in 1964 also indicated that the TLV was not applicable to insulation work because the dust counts did not accurately reflect the levels to which workers were being exposed (76): D1.uTsht ecolouwntsc,otuanktesnownistahmthpelinBgaudsocnhoatnadppLeoamrtboDgiuvset Canoaudneteqru,aatpepinedariciantiToanbolef tohled ainctsuuallathioazna, rtdh.eDwuorirnkgesnavwirionngmofenbtloacpkpseaanrsdepxitpreemseecluyodnussatyn.dRreemspoirvaatlioonf filters often clog after an hour's work removing insulation. History of the Asbestos TLV / 683 Table 2 Recommendations from Fleischer and coworkers (39), 1946 1. "During the handling, unwrapping, and unrolling o f the asbestos, considerable dust arises, but appears to settle readily. A very fine water spray should be used for wetting down the material as a high velocity spray stirs up dust" (p. 10). 2. "Inasmuch as this is a very dusty operation, the band saw should be enclosed in a room by itself and should be equipped with adequate local exhaust ventilation both above and below the saw table. Because of the mechanical difficulties in locating this exhaust properly, some of the dust will escape into the air and the operator should therefore wear an approved dust respirator" (p. 10). 3. "trCooungshidaenrdabdluerdinugstthisereaaisrleydswtahgeenstohfemasibxeisntgos..c.e.mTehnet disudstuinmepsesdoifntthoisthoepmeriaxtiionng warrants the use of exhaust ventilation or respiratory protection or both, although neitherisgenerally used" (p. 11), 4. "Several shipyards reclaim their scrap pieces ofprefabricated sections of insulation by grinding up this material and using it in the asbestos cement, alt of which contributes considerable dustiness. Normally thisjob is done at infrequent intervals and only one or two men arc exposed, but the operation should be isolated, general room exhaust supplied and an approved respirator worn by the operator" (p. 11). 5. "Because of the varied nature of pipe covering operations in ship compartments, general exhaustventilation is to bepreferred. Ifthe compartmentis large, such as the main engine room, five air changes per hour are needed. In small compartments, such as living spaces, ten to fifteen air changes per hour are requited" (p. 11). Data from Balzer (77) in 1968 also demonstrated that insulation work routinely e"xAcneyeodneed tlhoeo kaisnbgesatot sthgeuipdreelisneen.t Hbeasoisffeforerd t the he tfhorleloshwoilndg lcimritiitc ivsamluoe f th (T e L TL V) Vo:f 5 mppcf as recommended by the American Conference of Government Industrial Hygienists (ACG1H) in 1946 realizes that it is not based on solid evidence" (77). One final limitation of the guideline applied to insulation workers is that it was never intended to apply to mixed hazard exposures (40). Most asbestos insulation products, and essentially all shipyard work and most other construction work, involved mixed hazard exposures. Almost all insulation products were mixtures of diatomaceous earth, calcium silicate, silica, and asbestos. Schepers and associates (78) showed that such exposure to a mixed hazard insulation product dust itnhcereseavseesritthyeOrifstkuobefrtcuubleorucsulionsfiescitnioann.imAaslbse.sStoilsicaalpsorocdauucseessfifbibrorossisisa,nbduitnhcraesanseost been shown to affect the severity of tuberculous infection. Therefore, since most 684 / Egilman and Reinert insulation products generate a mixed exposure, the guideline could not apply to the use of this material. VIERWESOEFATRHCHE TAHNRDECSOHROPLODRLAIMTEITCVOAMLMUUENINITTYHE While we have examined the origin of the asbestos guideline and numerous problems with its applicability in the real world, we have not yet seen how it was viewed and used by industrial hygienists, researchers, and corporations. Most scientists who were conducting research for asbestos companies were aware of the inadequacies of the TLV. In 1943, Leroy Gardner (79), director of Saranac Laboratory, a major research center, wrote that the proposed asbestos guideline waIsnn1o9t4re7l,iathbeleA. sbestos Textile Institute commissioned W. C. L. Heraeon (80), Head Engineer of the Industrial Hygiene Foundation of America, Inc., to conduct a study ofthe asbestos dust levels in their membertextile factories. Hemeon found gthuaitdethlieneduacstculeravteellsy wmeeraesunroetdatchceepptoabtelentiaanldhaqzuaersdtioansesodcwiatheedthweriththeth5e mppcf use of asbestos. Although the study was neverpublished, the sponsoring companies were aware of Hemeon's observations that (80): Tmhilelioinnfoisrmthaotriooungahvlyaislaabfelenodrohesasniontfoprmeramtiiotncobmeepnledteevealsospueradnpceeimthiatttinfgivae ebietthteerrtehsattimsuactheaosfsusriadnecedsubsteinseosusg.hIttoirsanneevwerytharedlesstisckoof fgarcecaotemstpliimshpmoretnantbcee found for accurately measuring any remaining hazard in the dust zone below five million for the elimination of future asbestosis depends upon the degree ofcontrol effected now. Hemeon was not alone in his skepticism of the validity of the asbestos guideline. There was doubt as to the accuracy of the guideline in the first place, as evidenced by this excerpt from an article by Vandiver Brown, attorney for JohnsManville (note that he questioned the validity of the asbestos guideline, but still envisioned the value as a maximum level not to be exceeded) (28): Maximum limits are prescribed for a great variety of materials with which I have no familiarity, but it is my earnest hope that these limits have been arrived at on the basis of a betterfactual and scientific background than exists in the case of asbestos. The allowable limit for industries using this material is a "mandatory" requirement of not more then five million particles per cubic foot 10 microns or less in longest dimension. So far as I have ever been able to ascertain, no one can state with certainty wbat is the maximum allowable limit for asbestos dust History of the Asbestos TLV / 685 Corporate Reliance on the TLV Asbestos companies, through consultants such as Gardner, L a n z a , ^ VauoarewvaldS,tiwllerceorapwoarraetethuastethoef tghueidgeuliindeelwinaeswaaMs AlimCitaendd. As discussed earhe , SexcJeesde\dXthe ugui.ddelinye, apnrdotvhiadtetheevgiudideenlti,neparopdosed buy USPsHS int1938 c3ou5ld to insulation workers. From 1946 to 1961, no further smd.es were ctiomnedufrcaemde,totheexoanmlyinaevadiulasbt lleevdealtsa ianmdoicnagtedastbheasttoassbpersotodsucdtuustselersv.elDs gTMen"era*te"d thrForuogmh t1h9e3ir2ptroo1d9uc6t4s,'4u9sepreixmcaereydemdetdhiecagluaidrteilcilnees (a3n9d).8 epidemi.ologi.c . . . droome. beaos-robued disros. in insulauoo w o ta s -.md othets a w l 10 insulation produce (2). Of these - M e s . H, 8Lbeepsitdoesmcioomlopgaicnailesstbuedeinesc,ownceerrenepdubalbisohuetdanbdetawcetueanlly19r4e6lied upon the A*CrnGi1HH 2 n e as M ce that users of their * " f * * 7 " " ,,promt L ^ ,, a review of the medical liteiature would have tmapSoyaa,,n.mfouottas:tiWon wFlreoirkoehreer(anducseoowf ointseuhhuaidoushporowdu"cts g"^ re d* d7o*s t*levels that exceeded die guideline, based on nine studies published a t e 1964 mdteauug S e ed ed the guide. (2): - d (0 insuladon w o ta * me * ? ^ S T r e k e d on Ore guide. to protect wrekere, then the following steps would have been implemented. 1' Esxhpinoseudretshadtudriunsgt plervoedluscwt uesree wnootuuldndhearvseubfefiecniemntecaosunrterodl.,Acoltmhopuagrhe didnot follow up the Fleischer study in order to evaluate dust control methods and 2 r J S T w S ^ r e S T g i . on the need K> beep expos.. hefo. dj. guhh&ne and risks Ofnot dtUng to explained to product roe. Included would have been wanting about the possibility of disease from exposure below 3, Workers would have been informed of the need to use a personal respirator if dust levels were found to exceed the guideline. No astestos product manufacturing company, fowrever. everpuMi^wd a study ofttaam ount of dust genereled dining the nonnal use of its product m a wmk i ^ n " d no asbestos manufacture, e m pfoeed uqr -- P " packages of its product explaining the asbealos guideline, the n . ? b"eloTMw6ethpatrgouiddeulince,eorexthceeendeeedd5tomwpepacrfaorfeashp.irTathoer oifntlhye.dpusetrns fareviuanng 686 / Egilman and Reinert exposures during the installation and removal of asbestos products was the tremendous publicity surrounding Selikoffs 1964 study (81). By concealing data available to them, asbestos manufacturing corporations actively attempted to iinnafldueeqnucaectihees fvoarluperootefcthtieonasobfewstoorskgeursid. eline, rather than informing ACGIH of its CORPORATE INFLUENCE OF THE THRESHOLD LIMIT VALUE Corporate influence of the TLV has occurred on many different levels. The most important aspect of this influence centers on the failure to transmit informa tion, either by inadvertence or deliberate concealment, regarding both the inade wquitahcythoefitnhhealaastbioenstoosf agsubidesetloinsefiabnedrst.he full scope of the health effects a<=viau>d Adequacy o fthe TLV M Studies anville performed Corporatio in the n indic 1930s by ated that Metropolitan the guideline Life at needed the to request be "we o ll fbJeolhonws"- 5 mppcf (30). Also, as discussed above, Hemeon's (80) study of asbestos textile plants for the Asbestos Textile Institute noted the limitations of Dreessen's study, expressed concern that the asbestos guideline was too high, and questioned whether, by measuring particles instead of fibers, the guideline offered the proper assessment of the risk associated with the use of asbestos. Despite the possible itmhepvaacltidoiftyanoefvthaeluaastbioenstoosf tghueisdeelsitnued,ienseiothnetrhtehecoMnveetrnotpioonliatlanwLisidfoemstucdoyncneorrnitnhge Hemeon report was ever published. In response to these unpublished studies and the partial publication ofGardner's research by Vorwaid and associates (19) in 1951, however, some asbestos com panies adjusted downward their internal guideline for asbestos-containing dust In 1954, Johns-Manville established a different threshold for asbestos (82). Recog fniibzrionugs tchoamt pthoenepnattohfotgheenaessbisesotofs,atshbeesctooms-pinadnuyceesdtadbilsisehaesde aenmiannteartneadl gfruoimdelitnhee of one million asbestos fibers per cubic foot ACGIH was never informed that the tahsebiersptolasnctos.mJpoahnnise-sMuatnilvizilelde ammayodhiafvieedbaesebnesthtoesognulyidaeslibneesttoosccoonmtrpoalnthyetoduussteina modified guideline. Cancer and Corporate Influence on the Guideline The corporations also influenced the recognition of asbestos as a carcinogen in cthaercUinnoigteedn uSntatitles1.9A74lt,hboyug1h95A0CsGomIHe pdaidrtsnootf tohfeficmiaeldliycarel ccoogmnmizuenaistybeasntdosalalsoaf History of the Asbestos TLV / 687 the asbestos mining and manufacturing corporations knew that asbestos probably caused lung cancer (2, 50). The following opening statement by a lawyer for Metropolitan Life Insurance Company in a recent law suit illustrates this point clearly (83): Since the 1930s it has been accepted that exposure to asbestos could cause a pcouulmldopnraorbyadbilsyecaasuesceacllaendcearsboefstthoesilsu.nBgys..1.9.50Besfcoierent1is9t5s0kintewwasthwaet lalskbneoswtons in this country, the proof will show, that asbestos was hazardous and, indeed, could kill you. The proofwill show the United States Governmentknew it, the Navy knew it, the scientific community knew it, the medical community knew it One group Whose knowledge is not mentioned in the above quote is the public or workers. This is because, while all of these other groups may have been aware of the dangers of asbestos, a huge effort was made to prevent the truth from reaching the public, especially the worker. There are many examples ofthis effort, made primarily by asbestos companies and their insurers (1,2,33). After Gardner's death in 1946, Arthur Vorwald was named the director at Saranac. Li 1951, working from a draftGardnerhad prepared, Vorwald and others (19) published a report based on Gardner's dust studies in the 1940s. Prior to publication, significant portions ofGardner's draft were modified at the request of aosrbtuesmtoosrscionmGpaarndiensera'cstdinragftthdreoluegtehdL, eavneznat(h1o)u. gLhanGzaardhnaedraflolurnedfetrheantc8e1s.8topcearncceenrt of mice exposed to asbestos fibers developed lung cancer. Gardner (79) found that this was in excess. Despite the claim by a footnote in the published paper that a "complete survey" of Gardner's work was reported, Vorwald did not include any of Gardner's research on the relationship between cancer and asbestosis. In addition, Vorwald omitted Gardner's comment that the guideline for a safe atmospheric concentration of asbestos dust, tentatively set at 4 or 5 mppcf, was "pGroubiadbellyinuensrfeoliranbolex"io(u7s9)s.ubstances were one issue, but there was reason to think the thresholds were not protective if the substance was also a carcinogen. May Mayers (84) stated, "the maintenance in a factory workroom of Maximum Allow able Concentrations will not necessarily insure safe working conditions if a potential carcinogen happens to be present," In the same paper, Mayers identified asbestos as a probable carcinogen. Richard Doll (27) published an epidemio logical study in 1955 that provided more support for the generally accepted belief that asbestos exposure caused cancer. Cook (85), in 1956, said that TLVs did not p"krontoewctn"agcaairncsint ocgaerncsin. oTgheeniTcLVsubfostraanscbeesstaonsdwalisstneodt aadsbjuesstteods taosproonteectof gtahirneset cancer, despite the fact that Herbert Stokinger, a member of the Committee on 688 / Egilman and Reineit Threshold Limits from 1953 to 1975 (chairman from 1962 to 1975), advised that TLVs for carcinogenic substances should be decreased (86): Several industrial substances are known or suspected canccrigcns [rfei]; many more are suspect on the basis of animal experiments. As a suggested method of approach, the following is offered: To the level judged safe for other types of systemic injury add a safety factor for carcinogenicity. The magnitude of the safety factor is suggested to be from 100 to 500. Although Cook recognized in his introduction that asbestos was a carcinogen and commented on this issue before the Industrial Health Conference in 1955, no change was made to the asbestos guideline. This can be linked to the fact that Stolringer (87) was under the bizarre impression that asbestos acted as a car cinogen in England but not in the United States. In 1955, in explaining the ainscboenstsotasngt uciodmelpinoes,itihoen,sotaftteedn,v"aMryiinnegraalccdoursdtisngarteo cloocmalmityo,nlayndofthcuosmarpelepxotaennd tially capable of causing a variety of physiological responses. As a case in point, pulmonary carcinoma is commonly associated with the long-term Inhalation of asbestos in England, but not in A m erica" (87). Stokinger relied on information from Anthony Lanza, assistant medical director for Metropolitan Life Insurance Co. (retired 1948) and consultant to JohnsManville and other asbestos companies, to support the position that the effects of asbestos in Great Britain differed from its effects in North America (88-90). T-anra knew that there was no scientific basis for this argument. Nevertheless, hexepienrsieisntceed. tThoatptrhoemBotreitihshis daargtaumonenats,bLeasntozsa cuonuclodnvniontcbineglaypptrliieedd ttoo ethsteabUli.sSh. "differences between British and American findings." For example, he said in 1952(90): I used to hear frequently in Canada that the Canadian asbestos is less damaging than the kind used in England where the major part of the asbestos used, I am informed by my English friends, is Rhodesian asbestos, a variety quite dissimilar in structure and physical characteristics to the Canadian kind. Despite Lanza's attempts to justify his position, the previously published medical literature contradicted his assertions, and he had been rebuked by his contemporaries. Merewether responded at the 1952 Saranac Symposium to the above assertion made by Lanza (91): Firstof all, I think Dr. Lanza is misinformed about the proportions ofasbestos used and where they ate used in England. The original cases of Asbestosis, fifty years ago, were all Canadian asbestos. The earliest asbestos work in England was eitherseventy-fiveor eighty-two and there may have been some History of the Asbestos TLV / 689 crystalline fiber then, but very quickly the asbestos trade concentrated on the white Canadian crystalline. Sparks (92) had written in 1931: "Of the asbestos imported in England 80 per cent comes from Canada, so that it seems unlikely that you in the United States are dealing with a type of asbestos different from that employed m EnLgalannzda.w" as not ignorant ofthe conditions in the asbestos industry. ,,He was aware of the criticisms of his position that asbestos caused cancer in England but not in the United States. Merewether (91), the leading authority on asbestos disease in England, had rejected Lanza's hypothesis. Not only was the type of asbestos fiber used in the United States similar to that used in Britain, but it appeared to most researchers (with the exception of Lanza) that the dust levels in British plants were lower than exposures in American plants. According to Lanza (88): "This difference may be more apparent than real, but it is possible that the English factories may be more dusty than ours." According to Merewether and Price (93): "The same type of machinery is used in both countries bthuatnininBArimtisehricfaacntofarcietos,rideus.s"t-Acofntetrroallle,qrueigpumlaetinotnsseetomcsotnotrboel dmuosrtelegveenlermallByruitsieshd plants went into effect in 1931, whereas comparable regulations did not appear in theTUtanniatedwSastataelssounntiolt1o9b7j2ec(3ti4v)e. in his reporting on asbestos disease. He had previously altered published papers at the behest of asbestos manufacturers m order to help Johns-Manville influence worker's compensation laws. The asbestos mreliantiinvgelaynbdenmigannuimfaactguerifnogr acsobrepsotroastiiso(n1s).aVctaivnedliyveirnBfluroewncne(d94L)a,nszeanitoor apiorrptoraryaiac attorney for Johns-Manville Corporation, reviewed drafts of Lanza's 1935 paper on asbestosis. Brown suggested that Lanza's first conclusion contain a sentence that read: "Clinically, from this study it [asbestosis] appeared to be of a type rmidpr than silicosis." Lanza had removed the sentence from his first draft, but Brown told Lanza that this conclusion would be "favorable to the industry and we should tike to see [it] retained." In a letter sent 11 days later. Brown (95) sum marized his recommendations to Lanza: "All we ask is that all of the favorable aspects of the survey be included and that none of the unfavorable be uninten twioenaclalny dpeicpteunredduipnondayrkoeuratnodneDs rt.haMnctChoencniercllumtostgainvceesusjutsitnisfy`.bIrefaekel caonndfimdeinnet and Mr. Hobart's suggestions are presented in this spirit" Lanza (96) gave them a bWreiatkh.respect to the carcinogenic potential of asbestos, Lanza managed, to crea,e a controversy around a relationship that most scientists accepted. This artificial controversy and ACGEH's indifference to evidence concerning the carcinogenic potential of asbestos prevented downward revision of the asbestos guideline. Stokinger and the TLV committee members could have determined the facts 690 / Egilman and Reinert for themselves from published literature, but instead relied on the opinion of Lanza. CORPORATE USE OF THE THRESHOLD LIMIT VALUE proWteecthtahveeirsweeonrktehrastotrhuesaesrbseosftothsegirupidreoldinuect.wSaisncraere1l9y78u,shedowbeyvecor,rpthoeraatsiobnesstotos manufacturing companies have retrospectively relied on the TLV to protect them* selves from liability in asbestos damage suits. This reliance is called the "state-ofthe-art" defense. Asbestos companies argue that the existence of the ACGIH guideline relieved them of a responsibility to warn workers. The state-of-the-art is meant to be based on what people knew or should have known about asbestos hHeeanlrthy eGffaercrtasrddu(r8i1n)g, tahedteifmenesferaamtteor(nbeays,edouotnlinpeudbltihsheeudsaenodfutnhpiusbdliesfheendsedainta)a. seminar for defense attorneys given in 1987. Excerpts from the seminar, entitled c"oSmtapteanoifetshetoAwratrads adeDfeefnednisneg--t-hIseiirt Rcleaailm?,"thdaetmtohnestAraCteGtIhHe agpupirdoealicnheoefxaesbmepstteods them from their responsibility to warn (81): I. The Government Is the Springboard The argument is made continuously by plaintiffs', lawyers and doctors who frequently testify for the plaintiffs that the government was not involved in setting standards pertaining to asbestos in the work place. Jury studies have indicated that jurors still believe the government has a strong part to play in control of what goes on in the working environment and that the government has had great influence in that arena historically. Although OSHA is a creation of the 1970's, the basic mind set of the general public is that the government has been involved intricately in control of workplace exposures almost forever. Most o f the people today have not grown up in work in an atmosphere that did not Include significant govern ment involvement. This can become a play for state-of-the-art throughout starting with Dreessen as an official of the Public Health Service----After Dreessen. various publications, some of less importance, adopted similar positions. Interestingly, a study ofvarious state laws also indicates that from time to time states, including New Jersey, adopted the 5 million particle standard as a relatively safe working standard. Depending upon the state in which a case is being litigated, this can be important to bolster the argument there was both a standard and government involvement... . Although the American Conference of Governmental Industrial Hygienists is not an official government organization, it was made up predominantly of government hygienists and the sound of the name gives it an official connotation. History of the Asbestos TLV / 691 Garrard also offers advice as to how to use published scientific articles to strengthen the defendant's case. The following insight refers to the conclusions reached by Fleischer's 1946 report on shipyard workers (81): Among the conclusions is the infamous "number 4" which states, "since each of the three cases of asbestosis had worked at asbestosis pipe covering and shipyards for more than 20 years, it may be concluded that such pipe covering is not a dangerous occupation." In Fleischer's study, "such pipe covering" refers to pipe covering following specific procedures (Table 2), which are defined in their report (36, p. 11). Garrard appropriately uses the term "infamous" because he takes this quote out of context in order to misstate the authors' view that insulation work was hazardous unless performed using proper precautions. He continues (81): m . State-Of-The-Art Must be Kept Simple And Short From the Defense Perspective If the defense gets into an article contest upon cross-examination of plaintiffs' doctors or presentation of defense doctors, it is very difficult to win the state-of-the-art question, A better approach seems to be to take the dozen or so key articles which can be madeout as majorevents and dwell upon those at least to show that the various manufacturers and' suppliers of asbestos products were not historically without some scientific hasis for continuing to market products.... Additionally, industrial hygienists who are not medical doctors probably should be used to a greaterextent than they are used now to show the newness o f that field and how they in fact rely upon the threshold limit value concept in general. After all, the threshold limit value concept is probably the best thing the defense has in its arsenal Unfortunately, the threshold limit value "concept" was far from the best protec tion for workers and others, thousands upon thousands of whom have died orbeen injured as a result of unnecessary exposure to asbestos. In fact, it appears that representatives within the industry originally saw it as a means to protect their interests, in an era of increasing personal injury litigation. Discussing a plan for dealing with the "dust problem," industry representatives in 193S recommended that "Authoritative and approved standards for the control of industrial dusts" should be developed, "which, if complied with by industries, or by industrial companies, will act as a defense against personal injury suits" (97). Halfa century later, the scheme appears to have been put into practice, although Us flimsy appeal has been debunked by meticulous scrutiny. 692 / Egilman and Reinert CONCLUSION Wc have reviewed the history of the asbestos TLV in order to gain insight into current problems with occupational health standards. This review demonstrates the following: 1. The asbestos TLV, like most ACGIH standards, was based on short-term 2. Tanhiemaaslbaenstdohsugmuiadnelsitnuediwesasraitnhaedretqhuaanteclhyrorenvicieswtueddiebsy(9p8e)o.ple who cared little 3. TfohregarsobsessitnossuTffLicViesn,cliikese imnothset csucrierenntitfiTcLbVassisdoevfethloepiredgubiydeAlinCeG. IH, could not be relied upon to protect workers or the public. 4. Corporate influence of guideline-setting and medical literature protected economic interests rather than worker or public health. Companies never relied on the guideline to protect workers, and ACGIH failed to investgate a safe threshold for the use of this material. This combination of scientific indifference and corporate greed resulted in an occupational and environmental health disaster. This would be a matter of the past if there were not other potential disasters waiting to happen. OSHA, while a government agency and at least theoretically accountable to the public, publishes many gmdehnes taken directly from ACGIH, and both organizations are influential internationally. Any inadequacies in their standards will have magnified effects. Those who cannot remember the past are condemned to GreepoeragteitS. antayana REFERENCES 1 r' e.siie:a-r"cCh^--iha D. The silence: The asbestos industry and case study.Am. 7. Public Health 81:791-799, early 1991. occupational cancer 2. Castleman, B. I. Asbestos: Medical and Legal Aspects, Ed. 3. Prenucc Hall & 3. ABuCsGinIeHs.s,TEranngsleawctoioondsColifftfhse, NThJi,,rty1-9T9h0i.rd Annual Meeting o f the Ai CmGInH. rCmmncunmiHatl, 4. T. History of asbestos-related terminology. National Bureau o f Standards 5. GPurebalitca1tion 509Rie1s--ea1r8c,h19A78d.visory Board. Asbestos in the Great Lak. es Basrn. 6. KM iM^Pathophys^ology in relation to the chemical and physical properties o f fibers. 7. NMautriroanya,lHB.urMea.uDoefpSatartnmdeanrdtaslPCuobmlicmaittitoene 5o0n6;C1o3m3p-e1n4s3a,t1io9n78fo. r Industrial Diseases Minutes o fEvidence. Appendices and Index, pp. 127-128. Wyman and Sons, London, 1907. History of the Asbestos TLV 1 693 98.. MCocoDkoen, aWld.,ES.PHuilsmtoolnoagryyoafspbueslmtoosinsa.rByra.sMbeesdtoJs.is2.:B1r0.2M4e-1d.0J2.52,:19120275. --1026,1927. 10. Legge, T. IndustrialMaladies, p. 392. Oxford University Press, London, 1934. 1121.. AWnonouda,lWRe. pBo.rPtuolfmthoenaCryhiaesfbIensstpoescist.oBr ro.fJF. aRcatdoiroiel.s7fo:2r7t7he-2Y8e0a,1r9139436. , p. 106. HMSO, 13. CLoonlldiso,nE,.1L9.3O6.ccupational dust diseases. Bull. Hyg. 6:608, 1931. 14. raiman, p. Pulmonary asbestosis: Its clinical, radiological, and pathological features, 15. Danodnanseslolyc,iaJ.tePdurlmiskonoafrtyubaesbrceusltoosuiss.inAfmec.tJio. nP.uJb.lIincdHeHayltgh. 2135::116257--5--18132,8119.1393.33. 16. 17. GSaeyrmeras,nRw.oRrk.,oannpduDlmreoensasreyn,asWbe.sCto.siAs.sLbaesntcoestis2. :A9m1-.9J3.,1P9u3b2li.c Health 29: 205-214, 18. G19a3rd9.ner, L. U. Etiology o f pneumoconiosis. JAMA 111: 1925-1936,1938. 19. Vorwald, A , Durkan, T., and Pratt, P. Experimental studies of asbestosis. Arch. Ind. 20. SHtyagn.toOnc,cMup..RM,eadn.d3:W1r-e4n3c,1h,9C51.Mechanisms of mesothelioma induction and fibrous 21. LGylanscsh.,J.KN. aMtl..,CaanndceSrmInistht.,4V3:.7A9.7-P8u2l1m,o1n9a7r2y. asbestosis IH: Carcinoma of lung w 22. Easgbbeesrtto,sD-s.ilSic.,oasnisd. AGmei.gJe.r,CAa.nJc.ePru2l5m: o5n6a-r6y4a,1sb9e3s5to. sis and carcinoma: Report of a case 23. Hwoitlhlenbe,cHro. pBs.y, afninddAinnggsr.iAstm, A. R. Bevr.oTncuhbieorgce.n3i4c:c1a4rc3i--n1o5m0a, 1in93as6s.ociation w_ith pulmonary 24. aHsobmesbtousrgise:rR, Fep. oTrht eofctow-ionccaidseens.cAemo.fJp.rPimaathryolca1r8c:i1n2om3-a13o1f,t1h9e4l2u.ngs and pulmonary 25. aNsobredsmtoasnisn.,AMm,,. 7a.nPdaSthoorgl.e,1A9:.7L9u7n-g80c7a,n1c9e4r3fr.om asbestos dust in an_imal experi,ments. Z Krebsforsch 51:168-182, 1941. 2267.. DEdoiltlo,rRia.l.MJAoMrtaAlit1y4f0r:o1m21lu9n-1g2c2a0n,c1e9r4i9n. asbestos workers. Br. J. Ind Med. o2: 81-8_6, 28. B19ro5w5.n, V. Discussion. In The Pneumoconiosis, edited by A Vorwald, p. 569. Paul B. 29. HHiogegbienrs,,NEe.,wetYaol.rkS,il1ic9e5o0u.s dust in relation to pulmonary disease among m,iners .m the 30. Joplin Clark, Wdis.tIr.i,cat,nMd Disrsionukreir.,UP..SI.nDduepsttr,ioalfMtheedInicteinreio,prpB.u1ll4e5ti-n1,4N6o. .N1at3i2o,n1a9l1M7.edical Book 31. DCoremcspsacnny,,WNe. wC.Y, oetrka,l.19A35s.tudy of asbestosis in the asbestos texti.le. in. dustry. Pu.b.l.ic 32. HSaeyaelrths,BRu.llRe.t,ina,nNdoL. a2n4z1a,,1A93. 8J.. Etiology, symptoms, diagnosis o f silicons and asbes tosis. In SilicosisandAsbestosis, edited by A J. Lanza, p. 60. Oxford University Press, 33. rNaecwtieYmoarnk,, B19.3I8.,. and Ziem, G. Corporate influence on threshold limit values. Am. J. 34. NInodw. Minsekdi.,1P3.:5A3.1C-5h5ro9n,1o9lo8g8y. of asbestos regulation in United States workplaces. In Asbestos-Related Malignancy, edited by K. Amman and J. Aisner, p. 105. Grane and 35. NStCraGttIoHn., OTrrlaannsdaoc,ti1o9n8s7.o f the Fifth Annual Meeting o f the National Conference o f 36. AGCovGeIrHnm. PernotcIneedduisntrgisaolHftyhgeieEnigishtsth. CAinnncuinanlaMti,ee1t9in4g2,aftheACGIH. Cincinnati, 1946. 694 / Egilman and Reinert 37. Cook, W. A. Maximum allowable concentrations of industrial atmospheric contami 38. Anasnbtess.tlonsdTMexetdil.e1I4n:s9t3it6u-t9e.47M,1e9th4o5d. fo r Determining Asbestos Dust Concentration, pp. 1-11. Pompton Lakes, N J., 1963. 39. Fvelesisseclhse. r/,. Win.i,.eHt yagl..ATohxeiaclothl. 2su8r:v5e2y5o-5f 3pi9p,e19co4v6e.ring operations in constructing naval 40. 41. AACCGGIIHH.. PTrroacneseadcitniognsso fothf ethTehFiritfiteetehnAthnnAunanlMuaeleMtinegetoinfgtheoAf CthGe IAHC. CGiInHc.inCniantic,in1n9a6t8i,. 42. D19ri5n3k.er, P. Letter to Captain Ingram, U.S. Bureau of Ships. January 8 ,1 94 4 (National 43. AACrcGhiIvHe.sTarnadnRsaecctoiordnss,oWftahsehiTnegnttohnA, Dnn.Cu.a)l. Meeting o fthe ACGIH. Cincinnati, 1948. 4445.. MACcLGaIuHg.hTlirna,nAsa. cLtiGon.sTohfethpereTvwenetniotyn-TohfitrhdeAdnunsut adlisMeaeseetsin. gLaonfcthete2A:C49G-I5H3.,1C9in5c3in. nati, 46. 1961. ACGIH. Transactions o f the Twenty-Ninth Annual Meeting o fthe ACGIH. Cincinnati, 47. S1c9h6a7l.l, L. Personal communication, 1991. 48. NCGIH. Transactions o fthe Sixth Annual Meeting o fthe NCGIH. Cincinnati, 1943. 49. ACGIH. Proceedings o fthe Ninth Annual Meeting o fthe ACGIH. Cincinnati, 1947. 50. ACGIH. Transactions o f the Thirty-Sixth Annual Meeting o f the ACGIH. Cincinnati, 51. 1971. Stokinger, H. E. Threshold limit values. Dangerous Properties o fIndustrialMaterials 52. RAeCpGoIrHt,.19T8r1a,npspa.ct8io-1n3s.o f the Eleventh Annual M eeting of the ACGIH. _ _ Cincinnati, 53. A19C4G9.IH. Transactions o fthe Twelfth AnnualMeeting o fthe ACGIH. Cincinnati, 1950. 54. ACGIH. Transactions o f the Thirteenth Annual Meeting o f the ACGIH. Cincinnati, 55. A19C5G1.IH. Transactions o f the Fourteenth Annual Meeting o f the ACGIH. Cincinnati, 56. A19C5G2.IH. Transactions o f the Sixteenth Annual Meeting o f the ACGIH. Cincinnati., 57. A19C5G4.IH. Transactions o f the Seventeenth Annual Meeting o f the ACGIH. Cincinnati, 58. A19C5G5.IH. Transactions o f the Eighteenth Annual Meeting o f the ACGIH. Cincinnati., 59. A19C5G6.IH. Transactions o f the Nineteenth Annual Meeting o f the ACGIH. Cincinnati, 60. A19C5G7.IH. Transactions o f the Twentieth Annual Meeting o f the ACGIH. Cinci_nnati_, 61. A19C5G8.IH. Transactions o fthe Twenty-First Annual Meeting o fthe ACGIH. Cincinnati, 62. A19C5G9.IH. Transactions o f the Twenty-Second Annual Meeting o f the ACGIH. Ci_nci.n 63. nAaCtiG. I1H96.0T.ransactions o f the Twenty-Fourth Annual Meeting o f the ACGIH. C,inci.n 64. AnaCtiG, I1H96. 2T.ransactions o fthe Twenty-Fifth Annual Meeting o fthe ACGIH. Cincinnat_i, 65. A19C6G3.IH. Transactions of the Twenty-Sixth Annual Meeting o fthe ACGIH. Cincinnati., 1964. History of the Asbestos TLV / 695 66. AnaCtiG, I1H96. 5T.ransactions o f the Twenty-Seventh AnnualMeeting o f the ACGIH. Cincin 67. A19C6G6.IH. Transactions o fthe Twenty-Eighth AnnualMeeting o ftheACGIH. Cincinnati, 68. A19C6G9.IH. Transactions o f the Thirty-First Annual Meeting o f the ACGIH. Cincinnati, 69 ACGIH. Transactions o fthe Thirty-SecondAnnualMeeting o fthe ACGIH. Cincinnati, 1970. 70. A19C7G2.IH. Transactions o fthe Thirty-Fourth Annual Meeting o fthe ACGIH. Cincinnati, 71. ACGIH. Transactions o f the Thirty-Fifth Annual Meeting o f the ACGIH. Cincinnati, 72. 1973. Patty, F. A. (ed.). Industrial Hygiene and Toxicology, 2nd Rev. Ed., p. 399. Inter 73. science Publishers, New York, 1958. Schall, !.. Present threshold limit value in the U.S.A. for asbestos dust: A critique. Ann. 74. NFu.YltAonc,aWd..SBe.t,. e1t3a2l.:3A1s6b-e3s2to1s,i1s9, 6P5ar.t D. The nature and amount of dust encountered in aassbbeessttooss ffaabbrriiccaattiinngg ppllaannttss.onPothrteIhIIe.aTlthheofefafegcrtosuopfoefxwpoorskuerres.toPednunsstyelnvaconuianDteerepdaritn ment o fLaborand Industry Bulletin, No. 42,1935. 75. iHmaprrrioevs,inPg. aGs.beAsstobseshtyogsideunseticnonnacveanltdraotcioknysaridnss.hAinpnr.eOparicruinpg.:HAygp.r1ac4t:i2c4a1l --ap2p5r4o.a1c9h71to. 76. M an, W. T. Asbestos exposure during naval vessel overhaul. J. Ind. Hyg. 25:264-268, 1964. 77. Balzer, J. L. Industrial hygiene for insulation workers. /. Occup. Med. 10:25-31,1968. 78. Schepers, G. W. H., Durkan, T., and Delahant, A. Effect of inhaled commercial hydrous calcium silicate dust on animal tissues. AMA Arch. Ind. H ealth 12: 348-360, 1955. 7890.. GHcamrdcnoenr,,LW. U. .CP.roRpeopsoerdt MofoPnroeglrimapihnaorny ADsubsetstSousirsv.eUynfpourbAlisshheedstomsonToegxrtailpehI.n1s9ti4tu3.te. Unpublished study. 1947. 81. RGeasreraarrdc,hHIn. sGti.tuStteatCe ooufrtsheebaoiotka8s7a-1d2e.fDenesfee--nsiesRiterseeaalr?cIhnInAsstbiteustteo,sCMhiecdaigcoin,e1,9D8e7f.ense 82. JCorhendsi-tMorasnNveilwlesCRoer.pJoorahtniosn-M. AannsvwilleersCtooripn.,teerrtoagla.tAorniedsr.ewRespPriunbtelidcaintioSntos,ckEhdogledmerosn&t, 83. CPeonpne.l,aJnadn,ueatrayl2v2s,.1M99e0tr.opolitan Life, et al.. No. 89-5142 (Circuit Court Jackson, MS, 84. 1981). Mayers, M. Industrial cancer of the lungs. Compens. Med.4:11-18,1952. 85. Cook, W. A. Present trends in MAC'S. (Reprint of a speech presented at the Joint SGeosvseiornnmoefntthIendAumstreirailcHanygIniednuissttrsiaalt tHhyeg1ie9n5e5 IAnsdsuosctriaiatlioHne-AalmtheCriocnafnerCeonncefe, rBenufcfealoo,f 86. SAtporkiiln2g6e,r1, 9H5.6E.). APrme.pIanredd. Hdiysgc.uAsssisoonc..AQm..1I7n:d27H3y-g2.7A4s,1so9c5.6Q. . 17:284-286,1956. 87. HSteoaklitnhgReer,pH. 7. E0:.1S-t1a1n,d1a9rd5s5f.or safeguarding the health of the industrial worker. Public 88. Lanza, A. J. Asbestosis. JAMA 106:368-369,1936. 89. Lanza, A. J. Asbestosis. Paper read before the Fourth Conference of McIntyre 90. LRaenszeaa,rchAF. ouJ.ndCatoiomnmoennStsilicaot siSs,evNeonrtmh anSdaara, nQaucebSeyc,mJpaonsuiaurmy.28V-3o0rw,1a9ld52.Archives, Washington, D.C., 1952. 696 / Egilman and Reinert 91. Merewether, E. R. A. Comments at Saranac Seventh Symposium. Vorwald Archives, Washington, D.C., 1952, 92. Spatks, J. V. Pulmonary asbestosis. Br. J. Radiol. 17:1249-1257,1931. 93. LMuenrgews aenthdeDr, uEs.tRSu. pAp.r, easnsdioPnriincet,hCe .AWsb.eRsteopsoIrntdounsttrhye. HEMffeScOts,oLfoAnsdboens,to1s9D30u.st on the 94. Brown, V. Letter to A. J. Lanza. December 10,1934. 95. 96. Brown, V. Letter to A. J. Lanza. December 21,1934. Lanza, A. J. Effects of asbestos dust on the lungs of asbestos workers. Public Health Rep. 50:10-11,1935. 97. Weidlein, S. A. Plan for Study of Dust Problems. National Archives Record Croup 90. State Board of Health (0875-96-49, Pittsburgh). In correspondence from W. G. Hazard to L. R. Thompson, March 21,1935. 98. Roach, the doc S. um A. en , t and Rapp ation of th aport, reshol S d . l M im . i Bu t va t l t u hey are es. Am. Jn.oItrttdh,rMes he odl.d1s : 7 A :7 critical 27-753 analy ,1990 s . i s o f Direct reprint requests to: Dr. David S. Egilman South Shore Health Services 759 Granite Avenue Braintree, MA 02184