Document RJox7M2Mk1QOEZzV5poXrQad7

PLAINTIFF'S EXHIBIT DUP-935 J KTDICii STOVEIUAHCZ 0? ASBESTOS ffonma Praaencad by Haory J. Troehiaovie*, Sc.D. CbUf, Pbyalolocy Section Haakall Laboratory foe Toxicology and laduatrial Madleiaa at the Aabeacoa Saainar 9u Pont Country Club June 2, 1972 +' DU 037165 DUP 093S935 _2tk- 2 A Standards Adviaory Comnicta* for Asbestos (OSHA) has raeosaandad n exposure lisle of two flbart graacar ehaa five Bicron* la length par cubic caaelaacar. Ihl* proposal, baaed on a (National Ialtltuta of Occupational Safety and Health) NIOSH criteria document, vould not be affective for rvo year*, in order to allow the inaeallaelon of the nacaaaary engineering control*. Thi* adviaory coonittaa, rapre**ntin| government, labor, and induatry, alao suggasetd that the future itandard include a prograa of caoprehanalve medical lurvelllence which will be the topic of sy diaeuaaion eoday. According to the propoaed raeoenaadation*, aadlcal surveillance la required, except where a variance from the aadleal requirement* of thi* propoaed teandard have been granted, for all workara who ara axpoaed to a*beatos as part of their work environment. UP *1 For the purpose* of this requirement, the term "exposed to asbestea" will be interpreted as referring to 'bine-weighted average expoaurea above 1 fiber/cc or peak expoeures above 5 fibers/ee." 3UPI 2 Tb* major objective of *ueh aurvelllaaee will be to insure the proper miidlcal management of individual* who show evidence of reaction ta previous dust exposures, either due to excessive exposures or umnsual susceptibility. Such medical management might include job placement, improved work practices, caseation of tooking, or specific therapy for asbaa tea-related disease or ice complication*. DU 037166 OOP 0935936 -3 - H^wv*r# medical iurveillane* cannot be a guide to adequacy oi currant control* when tavironaantsl data and andleal asaalnation* only cover recant work* experience baeauaa of eh# proloosed latane period required for the davelnpaenc of atbeatoal* and neoplasms. According to NIOSH criteria, nadlcal lurveillance ahould include pre#*ployaane aedical examinations of applicant*, periodic medical evaluation* of exposed vorkere, and other i en--auilst Inm auch aa a comprehensive nadlcal asealnation on taraination of employment and cha aintenaaca of sadieal record* by the employer. First, lee's talk about the component* of the preplacasese aedical ezaaiaacion as recoanended by NIOSH. In taking a aedical history on a new employee, SUM *3 it is of special tneereae to know whether or not there was a peae exposure to asbestos or other "flbrosisproducing" dusc. Previous exposure, in conjunction with a history of cardiopulmonary or gaacro* intestinal disease, sight contraindlcete the placement of a new asployee in aa area of asbestos exposure. Suokiog habits are also an integral part of a sadieal history and nay iafluanea job placement since the peril of lung caaaer fras asbestos exposure is Increased by racking, in feet, tests conducted by lelikoff and Sacnd have shews that asbestos insula* tion workers who seeks have 90 tisas cha iacldaaea of lung cancer nnf ired to ssokers with no asbestos exposure. Tha second part of cha preplacement exaslaation would Include a cospleea physical with special attention to pulmonary rales, clubbing DU 037167 DUP 0935937 --H ........-- 4 of eh finger*, and other cardiopulmonary algn* often aaaociacad with fibnala la cha lung. Laboratory caati (hould incorporate routine ellnice! che*i*try, a cheat roentgenogram (PA 14" x 17"), aad aaeaurataaaca of pulmonary function. Ia eha KIOSH erltarla, cha aaaauraaanca of pulmonary function vhlcb ara raqulrad Include: 1) forcad vital capacity (IVC), i.e., tba greataet aaeunt of air chat can ba expired after a maximal Inaplratory effort, aad 2) forced expired volume 1a one aecoad (TEV^), l.a., eha fraction of the vital capacity expired ia one eeeond. The vital capacity (1YC) nay be normal but the timed vital eapacley (FEV^) greatly reduced la diaeaeee auch aa aebeatoele, due to lower airway coflatriction aad aubaequent lncreaaed realeeance to flow. Thua, if the reaulta from a pre-employment exaaination revealed a pre-exiitlai lung dlaeaae, placement of that individual la aa area of aabeetoe expoeure ahould be diecouraged. IUD1 #4 la'addition to a comprahanalve pre-eoploymenc examination, periodic medical earveillaace of aebeatoa-expoeed workera la aleo a rernmmenrfatico la the prepoeed KX0S1 criteria. Hiaeory aad phyelcal examlaatiom will be elallar to that of the prmt^loymenc axemiaatlon. Icwever, HIMI criteria ipeclfy the frequency of cheat x-reye aad pelaonary function teeta. Theee teate, to be performed at the employer' DU 037168 0935938 3 - *P**** will ba don* avary two year* on *11 asploytaa txpeaad eo esbaato* *nd annually on ehoa* Individuals: 1) who have history of 10 or sort ytara of aaployrane involving axposura eo aabaseos or, 2) who show roancganegraphie findIn** (aueh as null opacieiaa, plural pi*qua*, pltural thickening, or plaural calcification) which suggest or iadicae* pneumoconiosis or oehr reaction* eo aibastea, or 3) who have changes in pulmonary function which indicate reatrictiv* or obstructive lung diaaaae. gT.rnw at Other propoced recommendations in the VIOSH criteria entail a cowprahaosiw radical examination on earmnacloa of employment. Thi* exasdLraeion la to be performed on all worker* exposed to aabeatoa and should include the previously mentioned components of tha periodic radical examinations. Haineenaace of all nodical records of exposed employees is the responsibility of eh* employer; such records will be kept for a period to be determined by the Secretary o Labor la consultation with tha Sacretary of Health, Education, and Welfare. However, the present emergency standard for asbestos specifies chat ell record* be maintained for et leeet 20 year*, la far as access to radlsml record* is concerned, eh* proposed erieerle atate thee thee* be mad* available only to Health, Education, and Walfara and Oepasemant of Labor physlclana and radical consultants, and pfayalelana I 0935939 DU 037169 6 deslgnsead and authoritsd by ths tBployst. tfhathar or aoc eh* msdical rtprasaataeiv* of eh* snrploy*r would hav* aeesss eo eh*** rteord* 1* not el*r te this elms. SLIDE #6 On eh* rqu**t of eh* Director of KXQSH, Dr. Hereu* K*y, eh* American Industrial Hygien* Association (AIHA) ha* aubmletad le* coocMnts on eh* preposad NIOSB r*cnn*nriseion* which r eo b incorporated into eh* proposed standard for asbaacec. Th* AISA had avrl reservations about eh* details of th* rssdical surveillance procram ad has r*ccsn*nd*d eh* following change* 1) Sputum crtolorr {* of ^t*ie*d walu* and should not b* included. Because of chair sporadic appaaraac* and, la th* ease of fibers, eh*ir relation eo nene dust exposure, eh* AHU was at eh* opinion ebae eh* quantitative aas*atm*ne of eabesea* bodies and fibars in sputum was not, la e&a Ligbe of prsac knowledge, a vary usaful procedure. 2) X-rars should laclud* both laearal and oosterloranearlor view. th* AIHA f*ls that periodic x-rays can b extremely b*n*fici*l in detecting sarly lung serueeur* ehaag** if a laearal. as wall a* a pose*rior-aerior wi*w, is takan. 3) Medical records should b* made awallabl* eo thos* ohraiclaaa eo whom eh* employe* releases the information, and to the employer's medical representative. Sine* eh* eaolover is responsible for eh* health oi eh* employs*, le was f*lc ehae his medical representative should haw* access no eh* medical records. Za reference eo ehe proposed MXOSH recommendation* on medieal surweillaace, ehe industrial Union Department of th* API -CIO has sufamietad tea eommeaea eo ehe Occupaclonal Safety ami Health Adminiacreeloa. Th* VXOn ariearia on medical surweillanc* are acceptable to th* union with th* following qualifications: DU 037170 ot6S6Q ana 7 1) Medical pagination* *hould b* paid for br th* amlont and parfonead by cha phyeictaa ef cha tnrolove*' choice. th union faal* icroajly clue eh* employ** should have hi* choice of physician* and clue x*ninations by a company phytieian migbe, in team way, jaepardia* eha job security or job placaaane of eh* aaployaa. 2) ill aadlcal record* and raault* of ueh examination* should b cha property of tha employ** and ralaaaad only co auch parson* a* ha choo* and eo HEW who nay noe ralaaa* thaa co eha employer and who shall hold than undar conditions of * trice confidentiality. Ataln. eha union *cra*a* chac an employer *hould noe have access eo *ueh racord* in eha avane chac h* (cha employer) mifhe uaa ehaa acainac eha employ**. Should ehia rijhe of verkar* eo eonfldaneial handling of madleal iaiormaeioa ba incorporaead into law, nodical turvalllanca of axpoead workers would ba a dlfflcule, if noe impossible, problem. In (usury, I hava discussed eh* propoaad raooaawadaeiona on medical (urvaillanca which aay eventually ba incorporaead into eha nav aeandard for *ab*eoa. Uhachar or noe all of ehaaa lea** will b* iaeorporacad la noe known. Soravmr, aeae of eha raaoasaadaelona -- iueh a* periodic aadlcal examinations which include chase x-ray* and pulmonary function eaaes -- or* aouad and should ba uaad in monitoring workar* axposad eo aabaaeos. HJT/Jtd 6/1/72 DU 037171 Ik660 400 SLIDE #1 DEFINITION The term 'exposed to asbestos' will be interpreted as 'referring to time-weighted average exposures above 1 fiber/cc or peaks above 5 fibers/cc.' 4*- DU 037172 Zt6S6Q dfld SLIDE n 1. Proper medical harassment of individuals who SHOW EVIDENCE OF REACTION TO PAST DUST EXPOSURES DUE TO - EXCESSIVE EXPOSURES - UNUSUAL SUSCEPTIBILITY 4k- 2. Cannot BE A GUIDE TO ADEQUACY OF CURRENT CONTROLS DU 037173 WIP 09359-13 SLIDE #3 gREPLACEMFWT FYAMTNATTflN . History a. Past exposure to asbestos or other dusts b. History of cardiopulmonary or gastrointestinal DISEASE c. Smoking habits , Physical Examination - Special attention to pulmonary rales, clubbing OF THE FINGERS, AND OTHER CARDIOPULMONARY SIGNS . Laboratory Tests a. Routine tests b. Chest X-ray (PA 14* x 17*) c. Pulmonary function tests (FVC and FEVx) 4 3 DU 037174 *6S6Q SLIDE #4 PERIODIC MEDICAL SURVEILLANCE ----------OF EXPOSED WORKFRS 1, Chest X-ray and Pulmonary Function Tests a. PA - 14* x 17* B. FVC and FEVX c. Every two years on au. exposed workers d. Annually on the following workers: 2 THOSE WITH 10 YEARS EXPOSURE - THOSE WITH X-RAY CHANGES - THOSE WITH PULMONARY FUNCTION CHANGES 2. History and Physical Examination a. Cardiopulmonary signs or symptoms b. Smoking history c. Exposure history DU 037175 DUP 0935945 iz&,.am** fll--Nawteitii'igfe-Mi fwww-B-T-^iipi i- .-i H'jfrigg ..i `g'riilf HHE ~Srtffl'riR; il,;i. I mmst \ SLIDE #5 OTHER. PROPOSED RFPflMMFNnflTTOftfi 1. Comprehensive Terminal Medical Exam a, On all workers exposed to asbestos b. Should include components op periodic exams 2. Maintenance of Medical Records A. FOR A PERIOD TO BE DETERMINED B. Emergency standard states 20 years 3. Access to Medical Records Only by: HEWa. and Department of Labor physicians AND MEDICAL CONSULTANTS b. Physicians designated and authorized by the EMPLOYEE 9k6S6o ana *>U 037176 SLIDE #6 COMMENTS ON NIOSH MEDICAL .-SDRYEI.LLAHCE.PRQ6EAM ... 1. MM a. Sputum cytolosy of limited value and should NOT BE INCLUDED. B. X-RAYS SHOULD INCLUDE BOTH A LATERAL AND POSTERIOR-ANTERIOR VIEW, c. Medical records should be made available to THOSE PHYSICIANS TO WHOM THE EMPLOYEE RELEASES THE INFORMATION/ AND TO THE EMPLOYER'S MEDICAL REPRESENTATIVE. 2. AFL-CIO (Industrial Union Department) a. Medical examination should be paid for by EMPLOYER AND PERFORMED BY PHYSICIAN OF EMPLOYEE'S CHOICE. f^'ALL MEDICAL RECORDS AND RESULTS SHOULD BE THE PROPERTY OF THE EMPLOYEE AND RELEASED ONLY TOI - DESIGNATES OF EMPLOYEE - HEW (UNDER strict CONFIDENTIALITY WITHOUT RELEASE TO EMPLOYER) DU 037177 />6S6o ana '> maafei: jul \ <***>* kaimiiii. DiscassicK at FHES&mnar Htary <T. Irochiaovlct Q. This standard is atartsd primarily for asbestos worktrs but what about other workers that have axposurs to aabastos? I eaa see by tba criteria what they ara attesting to do, but bow any peepla ara va going to kasp undar aadical aurveiUanea? A. Evidently it u going to ba, at Xaaat tba propoad rseanandatlaa isya, aa aaplcyee doesn't bare to ba a "sows!lad asbestos worker". If tba saployee had aa aa^osura to asbestos greater than tbs definition (1 flber/ec) or peak values above 5, then ha is aa asbestos worker under tba lav and tbe aadical aurraillaace part of this lav will apply to bin. Q. If this ooeurs just one day over a tan-year period, does tbat keep hist under survelUeacef A. ter, geoo It's like, if you exceed tbe speed Unit on one occasion only, if you don't get caught at that aoacat by radar, you're probably all right. But this la sot defined as a aaa vhosa ocwgetlcn statistically srpcata bis to asbestos, like aa Insulation agpller, but rather any sployee vbo is upend to acre than 1 fiber/oe tine-weighted arerege. that, by definition, bring* bin under this progrsn. -4> - 0, What are sqp of tbe other dusts la addition to asbestos tbat you aade referenda Win your speech that should be considerad? A. Silica, coal duet, beryllium. pfaZggL I thlak the isporUnt tblag to note hare la tha direct head-on between the labor polat of Tier end the aaaagasast point of Tier (the dvm point at Tier) in respect to the aanfidentiality of aadical records. 8^6S 60 <MW DU 037178 -2 - labor wants to Imp thaa entirely secret fraa the cnployar. They have reason far it. V* don't understand that particularly la Du Pont because wa 've never epsrated in thia way. Scat of tbs trade* repre**nt*d. by the international union* have baas burned in the past. Whaa the esployer finda out that a man begin* to show icne sign* of pncumccanlosls, be'a fired--that'* the and of it. Theee people are fighting for their job*; they're protecting their poaitios*. They're saying, don't let the eaployer know that I her* apot* on ay lungs because if you do, be's going to fir* ae. There i* a lot of bitterness there and there's bees a lot of trickery, in a way, too. under the Coal Mina Safety Act this issue esae up and it was agreed that the ssployer would not take the cheat x-reys. - He would get them dose by seme independent person or a group of doctors who vers consultants. Tbay found out that scat of thass independent oansultaata tad agreed with the loyr time vben tbay would do a obaet x-ray, they would hare two filaa in the cassette. The esploywe would get one and the eaployer the other one. As a result, the united Mine Vorkere singly boyootted the whole program and demanded that all x-raye be taken by the Department of Health, Zduoatloa end Welfare. This fortunately didn't carry. HW wouldn't pick that vp. Sow I think that there are seme irrere penalties doctors who do taka double fllae. The Regulation* specifically say that yea' are not allowed to do It; it will be a violation of the law If you carried, out this kind of trickery. Labor'* demand has been backed that the iaftamaticn be eeofldrtlal to them and to HW. It is too bad ttefe thia of aplsyse-e^plcysr relationship exists in these Industrie*, fortunately, we haven't had to contend with that kind of thing in Du Pont. DUP 0935949 DU 037179 3 V wouldn't taka Idnaufi of labor on this point. I hope we css work out a satisfactory ecepremise because certainly la cur own Cccpsny, it is essential In tbe workings of our aedical progrea to let tkm doctor know the condition of his esployee. i don't see how you can possibly Justify bavins a plant doctor an tbe payroll If all of the labor people are going out and haring their examinations done by seasons else at tbe ea^lcyer' a expense. Without ajqr access by tbe plant doctor to those records, tbe whole systea will banc or fall on how they resolve tM issue. The final decision will be ande by the Departas&t at Labor. Q. Is there any possibility of a dual standard alone these lines of physical exaainatlcns, cue for the transitory type a^loyee versus the permanent aa^loyee with Du Pont? Has there been any discussion an it at all? A. I would interpret the proposed refutation to say that if you put a sen Into a position where he is e^eaed to acre than 1 fiber/oo, tbat be has to cone under the aedical surveillance progrts. Be has to be smined every two years on periodic oval nation until ha has accumulated 10 years closure, then be goes on an annual basis. I think that la the only difference. Q. I'a interested in how you keep track of tha asbestos worker who works with fortydifferent contractors over a period of years. Are there any guidelines^* fallow? A. Or. Zaaa Ton will notice that on tha pre-sgplcyaant examination, you will have to take a history of past eaposure. I think it would figure into that* If ha tolls yon that bo's nsvar had an closure In his Ufa bofero and you take his at his word, I think you're justified. DU 037180 DUP 0 9 3 5 9 5 0 Q. 2ov doi this time-weighted average ot 1 fiber/cc relate to the 2 fibars/ee previaualy diacuaeed is the recameadad standard? A. 3r. Zagp Juat like with noise, you bar* a aolaa limit that ia safe tar toman exposure and you don't have to veer protection hut at a somewhat lower level they will probably specify that you go into a conservation at touring program which Is medical rurreillance, and that'a what they're doing hare. IS6SC60 <tf|Q t i DU 037181 laajaiii:.^,,,! siiiiWi ,-- =-a'agsB-i rfsimaaaimmamiMii SURVEILIAHCE 0T T53 AOKSPHPg Thl Motion will indicate the method that li currently recommended by the Department of Labor to be used for evaluating environmental conditions of asbestos operations. But, before this is undertaken s review is to bo aids ot tho first aethod--lqplngsr collection tul the subsequent change to tbs present procedure of filter collection. Tbs first standard for ccotroll,Inc esporure to asbestos was recommended in 1938. This was based an a study by Dreessen, et el.* of four asbestos textile plants. Tbe study was a Joist effort by the U.3. Public Health Service and tbe north Carolina State Board of Health. A tentative limit of 5 million particles per cubic foot (appef), using tbs ispinger collection technique and light field microscopy, was suggested. Chase investigators found numerous eases of pneumoconiosis where concentrations exceeded this value end only three possible cases whan the concentrations were below this value. To recall a point, the latent period for developwaat of disease Is on the order of 10 to 20 years. In this study, only five persons had been exposed for sore than ten yeara to concentrations from 0 to A. 9 sgpef. Kona of 39 persons traced to concentrations below 2.3 eppef Reared evidence of aabestosls. Is addition, only six of these 39 had beanjiaployad more than five yeara. Another factor of this study was the length of a^lsyant of these vorken. Of the total 5^1 alloyed, 333 of than bed worked leas then five yeara la tbe textile Industry, 66 were employed far as long as tea yeas* end only two far set* than twenty years. She grange age of these textile workera was about 32 years. Dreeeeen, W. C., J. K. Dellavalle, J. I. Edwards, 3. V. Miller, sad R. B. Sayers, A Study of Asbestos!* in tbe Asbestos Textile Industry, Public Health Bulletin *Skl, 1998. DU 037182 DW 0935952 .2- The lnvet eigaeort raeognixad chat* Umleaeionn and tea cad, "5 nppcf say b regarded caneaeivaly at eha ehraehoid valua for tabai eot-dute axpotura until baetar data ara avallabla." Vhac about tha loplngar collaeeion technique chat vat utad In chit eudy to datarmiaa tha degree of duattnaaal Tha ttandard iapinger method waa uaad bacauta it vaa eha accepted anaat for aatataiag eha dutey eradat. Although It teill rataina that function coday, eha tread la toward tha raapirabla fraction and graviaeerlc naana of ataaaaaane. In tha Iapinger, air la drawn through a glaaa Jae aae at a fixed diatanee fro* eha boeeoa of a flaak. Tha Jet..it laaurted la watar, alcohol, or a aixcura of both. Aa eha pareielaa tcrika eha boeeoa of eba flaak ehay bacoaa auapaadad in eha liquid. Collaeeion efficientlet wary hue ara gaaarally on eha ordar of 981 for pareielaa graaear than 1 to 2 |A. Tha ecapla ante be eouatad within 24 bourn of collaeeion. Thin it eo raduea eha chanca of eha pareielaa eo floeeulaea or for tone null pareielaa eo go lneo aolueien. 4 aaapla la withdrawn from ehm eollaceing flaak and plaead into a counting call. Tha counting eall chould ba no nora chan tad na lane ehaa 0.25 on In dapeh. Saetllng tlaat of eha pareielaa . eha call wary dapending on their tlaa, danaley, and eha eollaceing aadla. Tha period eo allow for parelela tattling wnrlaa froa 20 eo 30 alaaeaa. All of eha pareielaa will not caeela la ehla clan pm. One# tearcad, eha couae auac ba eoaplaead within eaa alaucaa. All of chsaa faatora hawn eo ba racordad in ordar eo raduaa eha known wariablUtlas whan coopering teudiat lsvolwlag duoe counting. DUP 0935953 DU 037183 -3 Th micro*cope u*ad for cha Icandard duat counting mathod can, be a laboratory grade optical unit with a 10 povar objective lana. Counting la dona undar light flald technique* ae about 100 magnification. Iha araa to ba eouacad ahall ba daflnad prafarably by an ocular grid or by ruling* on tha counting call. Thia method require* vary claan campling and counting apparatu*, a duat-fraa araa for both preparation of equipment and for counting, experience with tha technique# of duat counting, and patlanca. Thia 1* a vary tedioua procadura and experience with it la not gained overnight. What are aooa of the laadaquaela* of thia procadura vhan compariron* are made with tha new method? in thoaa atudlaa vary fev fibers.vara tan la the counting call. Thera are too raaaona for thia; they are: 1) cha Impinger la not affieiant for cha eollactlon of fine parciclaa (fibera) and 2) tha raaolvlag power of tha microscope la noe deq\ite to detect aaall parciclaa. Tha laplngar haa a collection afflclancy related to cha aerodynamic cite of cha partleulata and la not affieiant for parciclaa with falling apeeda leaf than 1 m unit danalcy aphare. Electron alcrographe reveal that aany of tha alrboraa aabaaeoa flbara arm on cha oedar of hundredths to cantha of^a micron la diamatar. In eompariaoaa with other mechoda, it wee noted chat'the laplngar collected only about one out of every hundred airborne fibers. Of thm total duat count, fibere nada up uaually leaa than tan pmreant of tha total count. DU 037184 DU* 0935954 -4 - la addittos co noe being able to resolve vary aaall particles, cha all fibers would not sacela In cha allocead time to thae plana in tha call whara particles ara to ba couatad. This would alao raduca cha nuabar aaaa during tha eouacla| pariod. I^ln(ar samples ara not handy for loo* paraonal samples. This it primarily dua to both avaporatioa of cha abaorbiat nadia (alcohol) and cha movement of Cha workar. Tha eonfldanea limit* of a duat count Improve, aa cha numhar of parelelaa counted lasraaaa, Bacauae only a ftw fibara war* aaan in lmplntar samples, It waa decided co count all particle* In eh* countinf call ae eh* aaeabliahad plana. Thla raault gava aa overall appralaal of duaelnaaa rather than aaaoeiating a fiber count co a dags** of haaard. The original invaatigatora realized thla point. It waa fait by ehaa and others chat if chia laval of duaelnaaa (TIV) was not axcaeded, that the asbaseoa haxard would ba raduead. The TLV of 3 mppcf,based on tha early seudlas of Orsassan and other*, waa la effaee from 1946 to 1970. However, in 196* sad 1969, tentative standards war* proposed ehac were based on a naw aaehod of collection and eouneing. It via evident from the ptacadlng discussion on the Impinges eathod that anoe))$r proeadnre was naadad to obealn a atatlatloally useful index of airborne fibar aoaaaaeratlooa. latarest In eba fiber content arises from the naad to maeaur* that team in thaeaviroament that is eba most relevant to tha disease ceasing nachsnlam. A corralation batwaan fibar Most and diaaaaa or axpoanr* and health waa needed. DU 037185 OUT 0935955 5 At this aspect of asbsscos'fiber ooncencrseion to disease vu reviewed, ic aade kaon abac eh* British vers us In* a machod vhereby aabaseos fibers vara eouaead la eha workroom atmosphere. They had scarcad out la 1951 vlth a thermal praelpltacor. But bacausa this unit did aot count fibars longer than 10 ia, a battar method vaa sought. In I960, chay scartad using a long-running tharmal praelpltacor and vara abla to eollaee and count tha long fibars. Thay made a sacond change in 1965 vhan chay scartad collecting ssoplas with cellulose membrane filters. s an informational nets, In tha standard tharmal praelpltacor, dust-laden air Is drawn vertically into tha sampling hsad and dovn a narrow vareleal channel baevaan two glass coverslips. Halfway betvaea ehasa eve coverslips is stretchad a horlsoncal vira, heated alactrleally. Duse is daposltsd by s chatmsl efftec, opposlts tha vlra, la two scrips oa the coversllpa. The severally* are. ehea eouaead, dust side down, on microscope slides and eha dust la than eouaead. In eha ''long-running" tharmal praelpleaeor, eha duat-ladan air is drawn free a vareleal pasaage and along a horlsoncal channel, eha floor of which Is formed by a glass coverIslp. It first particles settle out treat eha air by gravity and eha raaaladar ara praelpleaead thermally DU 037186 -6With the Briciih already using a aeehod to count ub<i to* fibers la eh workroom arao*phr, we felt it ni ncei*ary to arrive at a n.ti procedure. In 1968 and 1969, tha American Conference of Governmental laduatrial Hygianiata pub 11ahad notleaa of lataadad changes to lowar tha TLV frees 5 oppef to 2 cppcf baaad on light field counting techniques. in addition to chit, a value of 12 fibera par milliliter of alt vaa auggaatad aa an alternative for the 2 nppcf. The fiber couae vaa to be determined by the membrane filter method at 430 X magnification, phaae eontraat 1 Huaination. Only fibera greater than } ia la length vara to ba counted. In 1970 and 1971, tha light field technique TLV vaa eliminated and only the fiber count technique vaa recommended. Alio ia there yaera, the TLV vaa levered from 12 fibera per ml to 5 fibera per ml. Thia change la the isum 11at and counting ceehmlque vaa brought about by work carried out by the Division of Occupational Health of the Q.S. public Health service. Their study carried out la asbestos textile pleats, urns concerned primarily with obtaining tome relationship of dust counts by lmplager aampling to fiber oouaea from membrane filters using e higher reaolutioo microscope objective for the latter. Tha information they obtained wjs not meant at that time to replace the standard lmplager method. With tha ratloa they obtained they attempted tos 1) Indicate an approximation of the relationship of lmptnger tonnes to fiber count* from Britain, DU 037187 DUP 0935957 -7* a) giva iso* indication of fiber counts fran personal staples, 3) ditinsia* sane index which say be used in the absence of bettar information to estiaata th proportion of ubesios la a duat e^orure. From thia study tha following ralatIonahip* wara dataralnad: right Plaid Tachniaua Mnferana mtar MathoA flbar length 1 sppef 1 agpcf 10 fibers/al 6 fibara/al all fibara > 5 us 1 iro<* 3 fibera/al > 10 ya Thia study ahowa tha affect on tha TLV lataadad ehaagaa of 1968 aal 1989 of 2 sppcf or 12 fibara/al for fibara graatar than 5 ya in length. Baaad on tha aatahliahad TLV of 5 mpef (till balng uaad at tha time of tha study tha faUawing egad-relent relationship* oaa ba stated: Total fibara - 50 fibara/al Fibara longar than 5 ua - 30 fibers/al Fibara longar than 10 ym - 15 fibara/al If tha ruggartad laral of #390aura vaa to ba limitad to 5 fibars/ol for fibara graatar than 5 yn is length, it can ba aaan that tha Inplnger ita. technique jgjttld require a TLV of leas than 1 ippof. Thia would ba naar tha lower practical limit of saaaitirity of tha lapingar technique. Aecurata --asm'--ita would ba vary difficult by tha lapingar method. fact waa that thia relationship was obtained far asbestos tasfeUa mils and would set necessarily ba valid for other Industries, la fast, tha results could not ba related from one plant to another for the saaa operation. DU 037188 iwwHigafc&Ml a snsia^ic:.:...rfmmmiijstim 'lit ttiaaju. -8 - Cn* definite result of this study was that the cstlaate of risk of disease should be based on fiber counts since this method yielded a sore direct estimate of airborne asbestos concentrations. This leads us to the procedure recoamended by the National Institute of Occupational Safety sad Health to be used for airborne determinations of asbestos concentrations. Collection of Stacie The saspIs should be collected cm a 37-olHlmeter "Milllpare" Type AA filter mounted In an open face filter bolder. The filters art contained In plastic filter holders snd art supported os pads which also aid in controlling the distribution of air through the filter. To yield a more uniform eesple deposit, tha filter-holder face-ops should be rirrsil Tbe filter* just described are often referred to ae field Monitor*. They come preassenbled from tbe MUlipore Corporation. The stated per* six* of these filters is 0.8 urn* Collection efficiency is very high for particles below the stated pore size. Particles are collected on the surface of the filter. They da not penetrate into the filter structure. It must be ophssized that this procedure is only good for MUlipore Ccrgoretlcc^filters. If tasf ether naferaae filters are used e relatlceship has to be Srelopad between both types of filters. Tbsre are three choices of filters that can be ordered for tbe field Monitors. She ono recoaoerded is tbe white with no grid mrkings. This filter la selected ewer the one with grid Barkings for two reasons. W lf 0935959 DU 037189 -9They tri u fellow*: 1) the aouncing atdia do* not clsar eh* grid airicing* on eh* filter, end 2) toaetlae* eh* grid seeking* any interfere with fiber* thee ere to be counted. The other choice, the bleek filter, i* not ebl* to be cleered. It la advisable to *al thee portion of eh* filter holder thee i* not removed during eh* stapling procedure. After stapling, eh* cop section that 1* replaced to cover the fee* of eh* filter, should also be seeled. Stapling flew rata* ney vary frea l lpa to 2.5 lpm which i* jute about the nsxlmue flow race obtainable by personal saapllng puap*. In one Federal Government publication eh* reconaandatlon was to us* 2 lpa as eh* flow rat* and a einiaua aaapling time of 15 ainutas when an evaluation was needed to decerain* if there was eh* possibility that the excursion Hale of 10 lb*ra/al alghc be axeeaded. There era *oae definite problems with such e recoamendatlon. They are: 1) When it is evident that the TLV is being exceeded, a 15-oinuc* temple aay be too long la duration. If too aueb aeeerlal is collected on a filter, ehere aay be sloughing-off of some of the heavy deposits of sacsrial, chars will be overlapping of with seme actually being hidden during the counting pfitae, aad witt heavy deposits, there aay be some shifting of the fibers whea the clearing aaterial is used. DU 037190 OOP 0935960 10 2) Th* pump that may b uaed at chi* tlat may not hava cha capacity of 2 ipm. Doaa chi naan the sample cannot be taken? Ho* What la raquirad chough la tha known Slow rata and cha length of aaapla tine. Thia reeconendation that la referred to above, probably la attesting to relate to cha counting raqulraaaaes thee are needed la order to obtain a rcaclatleally acceptable aaaiple. In order to hava an accurate eeclaata of cha cumber of flbera, the e catla deal error reaulting fro* the random dlecrlbutlon of the flbera muat be kept reaeonably low. To quote from the Criteria Document on Aabeecoa: "Since fiber counta follow a Poisson dlatrlbutlon, a count of 100 flbera In a aaapla would have a aeandard deviation of /100 or 10 flbera or * 10%. Thua the 951 confidence limit* would be approximately 2 *candard deviaeiens or * 20%. Slnea the 37 m filter haa an effaeelve collecting area of S53 m? and the projected field area of the Portou reticle is 0.003 at2, each field repreaenca 1/171000 of the aaapla. Baaed on chi* ratio, the following mmfeer of fields most be counted to aeasura the various limits la various sampling cimas:" if 55 $ DU 037191 I96SE60 SiigaiBaJliM rfliiliaaiicM u- Saspling Uaa 10 15 30 90 Flew SAtt 2 2 2 1 Nuabar of fields for 100 Flhara 10 fibari^ml ^35 91 286 22 lb3 12 100 20 90 2 2 10 zko 1 26 7 ZbC 2 18 k kto 1 W They do sot reccnaaad counting a field vith acre than 20 fibera hacauaa partleulataa aay ha praaasfe that vould interfere with tha accuracy of tha count. This rartrlcta tha aaapling paraaatara that ara recanaadad to tboat underlined in tha ahova tahla. It La suggested that at least 100 fliers ha counted la a saspla and that tha mlnliaai suaba? of fields should ha 20 and tha ---- ioo. Rreaently tha aourcaa va uaa for combine filter saaglea only count 20 fialda. ^dgeaeat la needed in term of vfaat va ara for and how to agplg thia idaa of atatiatical accuracy. We know that when va ara in a high duat ataoaphdra that va ara not going to aa^la for auch a long period that va vill overload tha filtar and aaka counting difficult. In thia eaae 20 fialda would probably ba auffleiaac. When va ara la a Ugh* duat ataoaphara va vill antcaatieally atagla for a longer period with tha idaa that enough fliers hare to ha oollactad to obtain a good count. Sven if vary for flhara ara collected on a long-rugaLag aaagla 1 MIT 0935962 DU 037192 - 12 - and for which only 20 field* r eoune*d, le would etll be possible to say that tha airborne eonceoeraeioa 1* lee* chan tcew value which would automatically be very low. Location of Filter Tha filter ahould be Located at near aa possible to eh* braathinj con* of eh* worker. The aoet logical placa la on eh* worker'* lapel. Normally either aid* would probably b acceptable. However, observation* should be mad* of air currents la eh* area as eh* duat may be directed to ona side or the other of eh* workar. Samp line Puma Thar* are a auaber of batterypower*d personal sampler pumps on the marker. Their *ashling rat** aa indicated earlier very from 1 to about 2.5 lpa. These pump* usually are able Co operate continuously for elghe hour*. The three namxfaccuser*' pump* aveilabl* are Kin* Safety Appliances' Monitere, Beadix's C-HO Personal Sampler and caaella'a Personal Sampler. Only the Casella pump does not have e visible rotameter. This is a definite disadvantage because as tha charge decreases on the battery, the flow rate could be reduced without It being noticed. With che other units It la possible to continuously chsck on the flow race during sailing and make required adjustments to keep e uniform flow rate. However, keeping e uniform flow race la not as critical as knowing tha volun* of air sampled. Knowing accurately cbm volume of air samplad i* essential. Tha aasnrata calibration of a stapling davica is nacasssry to cbm correct interpretation of aa laacsumanc's reading. Personal sampling pumps DU 037193 bUP 0935963 - 13 - should bo eaUbroetd prior to tholr being used, in the laboratory * wot ease aaear Is suggescad aad In eha field s rsesaaear Is eeavaalane. Th# caltbrseioo chain It as follows: eho flow raea standard instrument. the filter and ehe pump. Soap Is Proporotlon - (la addition, son article by Public Hooleh Service Includod with eboso proceedings.) The Bouncing sodium usod la this sochod Is proporod by dissolving 0.05 gas of soBbrono fllesr par aillillear of a 1:1 solution of dimethyl pheboloto and dlaehyl oxaloeo. The indox of rafractioa of cha aadlua thus proporod is KD 1.47. xe is doslrsd to havo somo separation of ebo indicts of rofrmeeion boewoon eha seating nodla, eho noabrono fileor, and eho aoboseoo fibers. This is not as critical la phoso contrast as in light fiold techniques. The Index of rofraceion for chrysoeilo osbosCos is 1.55 and for membrane filters is about 1.5. The fileor as received froa the field should havo eho face cups sealed in place. This is to assure unnecessary contamination and eho prevention of damaging the filter. To prepare e ssssple for aieroscopic examination, a drop of cha mounting medium is placed on a freshly cleaned, standard (25 m x 75 mn) dgO'Shaped place with an ere length of about filter with e scalpel end forceps and placed duat'Slde up on eho drop of mounting solution. If the mounting solution vaa placed on eop of the filter, elr bubbles could be foenod and it may be poaeibla far displacement of the fibers on the filter eurfece. A go. 1*1/2 coverslip, carefully cleaned with lone tissue, la pieced over the filter wedge. Slight pressure oa the covertlip achieves DU 037194 DOT 0 9 3 5 9 6 4 - 14 . contert between It tad tit mounting medium. The sample may be <"*! u tooa at the Mount Is transparent. This usually requiree about 15 minutes. Th saiplt should be count*! within 2 days after aouatiac. Evaluation of ths niter Sarnie Tbs filter samples mounted la ths manner previously dsscrlbad art evaluated la tarns of ths concentration of asbestos fibers greater than 5 U* la length. A microscope equipped with pbase-contrast optics aad a 4 sa "high-dry" achromatic objective is suitable for this determination, 10 X eyepieces, one of which contains a calibrated reticle at the level of the field-limiting diaphragm, should be used. Two suggested reticles are ths Porton or Patterson Globe and circle, fta Ported reticle la probably used more than the Patterson reticle. la the Porton reticle tbe left half of tha field serves to deflae ths oouatlng area of tbe field. Is referring to the counting accuracy, a of 20 fields or 100 fibers should be counted. A fiber is any particle that baa an aspect ratio of three or greater to ana. All fibers longer than 5 lib ere counted. Saznle calculation Tha following formulae are used to determine the number of fibers per ml: 1) K the effective area of the 37 am filter Is 855 * W 0935965 DU 037195 mm 15 - 2) Average nt count X jt Air voIum aanrpiad (ml) fiber*/ml th field r uaad hi* to bi eiUbntid prior eo couaeiaj wich mieroacopi ci| Diermictr. For chi* raapl, eh* amuapeiea it aid* chat it it 0.005 at'2 Iharafora: 27 - 171,000 Altunin* chi inrigi me counc pr fiild of 20 fiild* via 5 fibirt and ehi tanpli vu eoil*et*d ae 2 lieir* pir mimic* (2000 al/nin) for 90 Minucit: thias Principle* of Stapling - (Thi* **ctioa la quoted from thi Critirii Doeuainc oa A*b*to*j rri*v* ch* eople vary eoneitily.) "A duie *plio* procedure mutt b* deeigned to chie tample* of iceuil duie eoaeiacrieloei in collected accurately iad eooaiacenely. Th* raault* of eh* ulr*li of Chat* aaotpl** will nflaee, realiteically, ch* coaeeaeraeioaa of duie ae ehi plica and eiaa of *aupllag. la ordac to colliec ta*pl* r*pr*tneaeiv* of alrbora* dust, which i likely eo aoeir eh* tubjact't reapiracory *7* cm, ie la aeeeaaary eo poaltloa colloeeioa epparatu* niir^M ao* end aoueh of eh* tub j*cc or in hit 'breaching Tho coooeatraeion of daae la eh* air eo which a worker la aapoaad will wary, depending upon eha aaturi of eha operation aad upon eha eypa of work performed by eha oparaeor aad eha poaieloa of eha oparaeor relative eo eha ourc* of ehi duae. Tha Mount of daae Inhaled by a worker 1 0 0935966 DU 037196 - 16 - can vary daily, ssansonally, and with cha weather. in ordar to obtain representative samples of workers' exposures, it is aaeaary to collaee samplss undsr varying condition* of waathar, on diffarant day*, and at diffarant elms* during a *hifc. Tba parcaneaga of working time (pane on diffarant taaka will affaet cha concaneration of duat tha worker iahala*, aioca cha diffarant taaka usually result la exposure eo diffarant eoaeentration*. Tha percentage can ba daeemlnad from work schadulas and by observa tion of work routlaas. Tha dally average weighted axposura can be determined by using cha following formula: (Hour* X cone, cask A) + (Hour* X coat, cask B) + ate. 8 Hour* (or actual hours worked) Tha concentration of any air contaminant result ing from an industrial operation also varies with time. Therefore, a longer sampling tima will better approxisMta the aceual average." Soma information has bean dona on Insulators and tha various casks chat they perform la their work. Tha jobs performed by cha Insulating worker hav^Beea divided Into six areas and era outlined as follows with cha approximate time spent at each teak: 1) Prefabrication (10%) materials are pro-one and shaped ualng hand or power saws 2) application (10%) materials are fitted, hamared, or earvad and attached to cha surface to ba covered 1 MIP 0935967 DU 037197 AMilMWB Hi--iliWiirn liiiiw...... Sri M rw - 17 3) finishing (30*) materials are coated with asbestos containing ceacnti, racing, asbestos or cotton doth, or sealers U) Tearing Out (10*) removal of old or unusable materials in the process of insulating or reinsulating 5) Miming (5*) cements are mixed separately or in combination In buckets or troughs 6) General (5*) Meaning up of old Insulation, transporting of materials, etc. In one sat of studies the following asbestos fiber concentrations were found at tbe various tasks: Coeration Prefabricates Application finishing Ttaring Out Miring Oanaral Bean 9.0 5.3 2.9 9.2 2.6 5.0 Concantraticn SSI1 0.1 - 25 0.1 - 65 0.1 - 25 0.2 - 27 0.2 - 18 0.1 - 23 32>cf Mtan 7.0 3.7 2.9 5.8 8.5 1.6 Trcm values in tha range column, it will ba notlcad that thara mr - is a vide variability of airborne concentrations. It senes that there are ten definite operations of significant exposure--prefabrieation and tearing out. Ollt> 0 9 3 5 9 6 8 DU 037198 igg--airgiBHi --Mi . 13 Thia table ia not aunt to indicate vhat the apecific problea rtu ara tad the airborne eoncentrationa that may be exacted. Svery altuation la different--tlaaa apa&t on each operation, the anriromantal influancea on the area (vlad currenta priaarily), the work load, Individual work habita, ate. Evary location muat ha evaluated Individually. RJH/neh/jtd June 28, 1972 i DU 037199 OUP 0 9 3 5 9 6 9