Document ev51k64M1jnqLJbjvJgkk3pVm

FILE NAME Manville JMA DATE 1968 June 10 DOC JMA338 DOCUMENT DESCRIPTION Summary of Seminar on Respiratory Protection for Asbestos Workers 2060 Draft June 10 1968 Summary of Seminar on Respiratory Protection for Asbestos Workers Participants , a Howard E. Ayer Occupational Health Program PHS E. J. Baier Pennsylvania Department of Health J. LeRoy Theodore Balzer University of California School of Public Health Berkeley H. Brodie New England Insulation Co. Boston Massachusetts William A. Burgess Harvard School of Public Health Boston Massachusetts W. Clark Cooper University of California School of Public Health Berkeley Lewis J. Cralley NCUIH Public Health Service R. M. Edmiston American Optical Company Leon Horowitz Certain Products Ambler Pennsylvania Albert E. Hutchinson Washington D. C. Hutchinson Asbestos Workers International Association H. L. J. Levine Loring Corporation Asbestospray Sprayed Mineral Fiber Association Hollingsworth and Vose Co. W. Groton Massachusetts Jeremiah R. Lynch Occupational Health Program PHS C. R. E. Merkle John P. O'Neill Jr. Mine Safety Appliance Co. U. S. Department of Labor LSB Pittsburgh Pennsylvania L. N. Rodenhouse Protection Equipment Company E. Lynn Schall New Jersey State Department of Health Robert H. Irving J. Schutz U. S. Selikoff Mt. Bureau of Mines Pittsburgh Pennsylvania Sinai School of Medicine New York . . as tore ! ae . Faw , al hey ane ee tee ge . A ag . . me Sy at aan i MOR -ee or t - ge ve Tt Pras cte het : i * eo ar BT rag ote aN ee Se aa . gt r TS Jue). Clifford Earle P. L. Sheckler Shoub U. S. Manville Corp. Manville Bureau of Mines Washington D. New Jersey C. Glen W. Sutton Occupational Health Program Public Health Service John Vyverberg Corning Fiberglas Corp. New York City Konrad Szymczykiewicz Institute of Chemical Industries Poland Occupational Hygiene Textile and Discussion Summary Dr. Selikoff opened the seminar with a discussion of the problems of lung cancer and mesothelioma among asbestos workers He stated that the problem of asbestosis the pneumoconiosis which occurs in asbestos workers and rays now a relatively minor effect He presented to illustrate his point A principal effect tables of data was said to be thickening of the pleura This is a unique physiological effect resulting from asbestos exposure Unlike the development of asbestosis pleural thickening was not directly dependent Pleural calcification was given as another physiological effect which was unique to asbestos workers He presented data on calcifica- tion versus length of time from begining of asbestos exposure little calcification was seen at less than 20 years from onset Very of exposure More detailed information on pleural the found in his paper in Annals of the New York Biological Effectosf Asbestos pp 351-367 calcification may be Academy of Science In a discussion of the finding of lung cancer among asbestos workers he referred first to the findings of the Chief Inspector of Factories in Great Britian These findings are discussed by William eeneer Pass Para. | ; be. ate y,. biRi ow t Pry ester cts an jae oa> ~ . : hoe Ne ce ne ae a aw Te rae we a ee mas eg oa: e te -j3- a r Buchanan in "Biological Effects of Asbe Stos," pages For Buchanan Biological Biological those those Effects Asbestos One out every workers workers dieing of asbestos asbestos related discases five died died Was compared normal normal cancer of the lung lung lung or pleura . This rate about one out of finding of Wagner He referred also and Marshon Marshon the Medicine ; 1960 who ( British Journal pp 260 found found Industrial an invariably . fatal f disease = 47 4747 cases cases cases F of of of mesothelioma mesothelioma mesothelioma mesothelioma mesothelioma people people ie @ uu fe) a G o er fe) ft) nm oa o A wn Bronchogenic carcinoma Pleural mesothelioma Peritoneal mesothelioma Cancer Cancer stomach and and stomach Cancer Cancer Cancer all other 42 3 1 29 20 1963-1968 25 3 10 9 8 67 6 11 ll 28 28 Deaths of NYC Asbestos Insulation Workers Cont) All other Total deaths 1943-1962 148 225 1963-1968 35 107 Total 183 332 Cancer all Asbestosis 95 377 ? 55 51 17 150 29 lle summarized his data on insulation workers by saying that more than 50 percent of insulation workers who died in the last 5 years have died of some form of cancer Therefore in the present union membership of 18,000 we may expect in excess of 9,000 deaths to be attributed to cancer Dr. Selikoff also presented results of radiological surveys of populations in two countys In county A which contained an asbestos mine 499 cases of calcification out of 6312 total were found In counter B there were no cases of calcification out of a total population of 7,701 The finding of Drs M. L. Newhouse and II Thompson as reported in Biological Effects of Asbestos pp 579-588 579-588 were also mentioned compared the cases of mesothelioma in a London hospital with a They control group which had other diseases as shown in the following table Asbestos History of Mesothelioma and Control Groups Industrial exposure to asbestos Relatives worked with asbestos Lived within 1/2 mile of asbestos factory Mesothelioma Series 31 41 9 12 11/36 31 Control Series 6 BZ 1 1.5 5/67 % Pres. ae ee ; ye aeahe, Oe TEN ete SED oe * Oe eni rn aan nS tte ate See a. f i) ro ye ! 7 . te oa var meee 7 meee pete \ Be ee Yate eh BS ak a ey wrSge! t ea ee a Le Fe t ete 4 eM - oe 4 . ety 4 lle also mentioned the study el Pl Lieben of mesothelioma in the neighborhood of a factory in Pennsylvania for Dr. Selikoff's thoughts on respirators were that asbestos workers must be able to provide protection such respirators for the workers even when the exposure is low The respirators must be efficient for small particles and fibers with extremely small diameters The mask very should provide protection for intermittent exposures to high peak concentrations in otherwise low level environmental exposures The respirators themselves should not use filters which fibers since the asbestos fibers may slough off and contain asbestos create an asbestos exposure independent of the occupational exposure Dr. Cooper spoke briefly of the study of West Coast insulation 7 workers He was dealing with a younger population few had been in the trade more than thirty years Some mesothelioma had been found there was a definite excess of lung by Dr. Selikoff and he saw no cancer the general trend was as reported reason to disagree with Dr. Selikoff's conclusions Dr. Selikoff mentioned that in a review of 70,000 deaths in the general population only 11 had been reported as mesothelioma He felt in recent years and there appeared to be a of mesothelioma after exposure to asbestos long wait for the development Fry ; of be ye es Cr aoa | poe' roy (iene ris , G6 Aye rae \ ; eo: te: 2 ety * bee. nee To a Matty Seategite OAT eM Nt se) po a errere te rane tee te Sh meg tes Sy : rar Le ast ee as awe ee Se Te < . ett ee Ce ar Thee vey SO Ca : . ta2te yo 8 meye se, re a ac a | or when provided were sometimes not satisfactorily maintained The general impression of industrial hygienists who worked in industry during those years was that exposures were generally very much higher than they should have been Mr. Sheckler in reference to Dr. Selikoff's discussion on the African asbestos workers stated that 1 the exposures in South Africa were unique The workers were continually exposed to asbestos specifically crocidolite In the area where these cases occurred crocidolite was used to pave roads provide a floor and a roof for their homes the children played in it and there were all sorts of incidental exposures 2 Further studies by Wagner have not detected many cases of mesothelioma in other South African crocidolite mining areas 3 In most instances in the U. S. we are not aware of what type of asbestos the workers have been exposed to It is certainly unproven that all solely mesotheliomas occurring in the U. S. were caused by asbestos bo 4 It must be kept in mind that smoking habits of the workers are important 5 It should be remembered that mesothelioma is a rare disease Even the study in Pennsylvania so indicated With reference to the concentration of asbestos in shipyards previously discussed Mr. Schall recalled that studies of workers in the New York chipbuilding industry showed impinger counts to be on the order of 12-15 mppcf ork relationship to mesothelioma and other cancer stated that he had Vor thoroughly reviewed the use of insulation materials by west eEre coast insulation Oe workers In the period from 1913 to 1968 there was no crocidolite used Oate in insulation products on the west coast eo The question was raised of the reliability of mesothelioma rates Semanl among the general population in the U. S. Drs Selikoff and AY Cooper venatis agreed that there were no reliable data on the general population From oere a study of death records in the Bay Area Dr. Cooper is convinced that mesothelioma is dignosed at present As the disease becomes more widely recognized the number of cases is likely to increase Mr. O'Neill spoke briefly of a study which the Department of Labor is having conducted on compensation cost present and projected , for asbestosis and berylliosis He stated that the number of cases were considerably larger than they had expected even though they may have only scratched the surface of the number of cases actually existing He felt that other causes should be considered Radon daughters for example may have influenced the development of cancer He felt studies should be extended to other factors in the environment direct Mr. Sheckler brought out relation to lung cancer the point that pleural Such plaques are seen plaques have no in one specific mining area in Canada not in another area quite similar and only 50 miles away : c ' tity .% aK & ardwt of : t woh rroel ~ Rit t , 4 v wy?rahos bw. . -9- Dr. Selikoff stated that he could not explain the reason for the lack of plaques in one area He could relate the a plaques to the Tye occupation of the indivual the specific Do, known cause is not n 1 Lynch briefly reviewed the Aes exposures which occur Sy now in the 3 manufacturing of asbestos products in the S. In the asbestos textile | Amosite is used 4 Por l IRg? In two plants el 0. Cr al exceed 5 mppcf at for fibers longer In the less well controled controled factories concentrations times with fiber concentrations about 20 fibers per cc than 5 p factories is used Although exposures are continuous throughout the the are concentrations are greater near the machines lower in the manufacture of friction products In general concentrations than in textile manu- facture Dust counts will go up to three mppcf and fibers longer than 5 will range up to ten cc however in some factories there is a for pressure pipe manufacture Dust several mills are completely under 2 on the order of 1 to 8 cc significant amount of crocidolite used counts go up to 3 mppef although mppcf Fibers longer than 5 ... are a weg, | ah Tie . ae Eaod oy.oeor neareat eP rer 4 ee ry 8 pe ng eee es, . Mee EL cs f eet OR of vy RD o. - 10 In insulation manufacture five plants have been surveyed up to this time Of these two have used all amosite and the others a mixture of amosite and chrysotile Where chrysotile only was used plants were relatively clean dust counts would run less than 5 mppcf and fiber counts would be low Where amosite is used however counts were relatively high as compared with either the U. S. and British limits Fiber count would average over 5 cc with some running as high as 50 cc Exposures were heavyest in mixing forming sawing and scrap handling Mr. Lynch mentioned Dr. Enterlines data on lung cancer in an asbestos manufacturing cohort of 2.3 for the textile plants Enterline found a standard mortality ratio and 1.3 for the friction plants Since the textile plants are normally twice as dusty this suggested a response relationship in the development of lung cancer Mr. Baier of Pennsylvania reported that some areas had relatively constant concentrations over the years and had remained consistent for 30 years Some areas have tended to decrease with time Weaving and similar operations were among those which seemed to be constant with time In the application of asbestos insulation some operations such as sawing generate tremendous quanities of asbestos dust Other operations such as cementing produc low concentrations This leads to very fluctuating concentrations with a tremendous exposure for a short period of friction plants time then very little are quite different in dust then another high xt bet exposure for the textile The plants es ; = = gl * > Nasa re in be threshold operations operations Stated that in Dr. Steamfitters exposed exposed asbestos Selikoff asbestos Hutchinson these projects noted that on large certain full Mr. Hutchinson certain were assigned assigned time prefabrication prefabrication that they were surveying Mr. projects projects _ Baier were Crying to obtain They approved respirators surveying construction construction ventilation controls the use use af of Mines Said that the calcium silicate asbestos was usual] insulation with 19 to 15% smal asbestos asbestos feet. At this height the worker worker must Cut with a hand stand stand on a small: saw can fall 300 feet feet the ground difficulty Problem, He found in even making workers Mr, Balzer wear hard insulation reported reported findings in workers workers Local 16 in the Surveys of tho exposures Of these Francisco Bay area, The shipboard shipboard these workers application were more less less open air; in the many many of workers workers were outlined findings small confined ned with with Spaces, He outlined his Local the findings Francisco Bay area, The The use of materials materials Var ied the more or less as the following {llustrated by ae vse K: ee Soot, foes . tSyy , te, ry . aA woe vty Relative quantity Chrysotile - oe Loe al Years ~ eae % Amosite Amosite . ras Insulation workers averaged 45 of their time with material contain- ing asbestos 45 of their time with material containing fiber glass and 10 of their time with foam glass styrofoam and many others Insulation work is divided into 6 categories Prefabrication application mixing finishing tearing and general clean and repair The grand mean r for these operations was 2.6 mppcf The average of means for prefabri- cation mixing and tearing run 4 + mppcf These operations account for 30 of the 45 time spent with asbestos 13.5 of total time Peaks run from 1-26 mppcf with those in sawing up to 183 mppcf Approximately 1/3 of the fibers run 88 of the men in the union work in heavy and light construction In marine construction and repair the grand mean equals 5-6 mppcf for 45 of the time Fiber counts have a grand mean of 10 fibers for 45 of the time More detailed findings are reported in Journal of Occupational Medicine 10 Jan. 1968 tant. ae , : 9 He Spee eS or ee? ay Mea ss . cee pe. shat * SS Rey,ee ; an . . a. Weare rn on . ORT ae ws rae ene yO OF : 13 The ancillary trades also received substantial exposure In answer to a question he stated that i. essentially all fibers seen in samples oad the are asbestos At the present time asbestos workers do not wear respirators P72 ncoerant Dr. Selikoff gave some figures on importation of asbestos In bon 1930 and 1935 we imported 500 and 100 tons respectively of amosite at the present time we import 25,000 tons per year He further stated that te in studies using major suppliers some orginal amosite discovered in store rooms of the mesothelioma has been developed in animals Fleischer's ne study in 1940 to 1945 also found that workers were exposed to less than the threshold limit value Balzer stated that from 1941 to 1950 only amosite was used for marine construction His measurements of airborne 99 per cent were less than 3.5 in diameter with from 175 to 250 Angstoms fibers indicated that a minimum ranging Mr. Hutchinson presented findings of a survey of members of the asbestos workers union made in 1967. Out of a 17,996 membership 11,593 65 responded to the questionnaire The questions and answers follow Of these 85 are regularly employed 1. Are present masks satisfactory a Yes - 31 b No >> 41 2 What are the difficulties with the present masks 8 Comfort of fit - 37.6 % b Breathing > 21.4 C. Filter difficulties 10 d Vision - 4.0 ~~ oS re werk . oye ee oe eee - 14 3. Do you wear masks on dusty jobs? you wear - masks b. Never - 50% . Sometimes - 50 . Usually - 12 d several several categories for leading leading ones a. Restriction of 8 Restriction breathing breathing - 17.6 b Uncomfortable Uncomfortable - 7.8 sweatiUnncogmfortable C. 7.1 t sweating d Irritation Irritation 6.9 e Clumsy uncomfortable 5.0 clogging uncomfortable filters - 4.7 -_ Dr. Cooper stated that responses workers indicate approximately the same l. Never recommended or 2. Never recommended - 30 required 3. Never 4. worn = 35 Sometimes Usually always always 38 of 200 West results - 50 Coast insulation Of those those wore ae approved piece piece respirators respirators In most cases gauze similar similar to surgical only 5 or % Wore Bureau of Mines the mask consisted Simply of a mask Some typical objections are 1, Breathing restrictions 2. 2 Hot sweaty 3. Irritation 4. 4 communicate ~~ REI Mey me wre, we 2 RRR Teg oy fy Tow ny woe wn Raters voy woe ., ny we tg oN, wa 6 pa ran de : a wee ww f >> 15- Typical quotes which were encountered 1 I wear one when it's very dusty 2 I wear one when I work in a confined space 3 I wear one when I work with glass 4 I never wear one They drive me crazy 5 I wear one only when the dust is so bad I can't stand it 6. I wear the handy disposable 3M type In a discussion of these findings Mr. Balzer noted that on the West Coast only 10 out of 400 were wearing Bureau of Mines approved respirators these were in cases where extreme dust concentrations were encountered Younger employees seem to be using masks much more than the older workers He attributed this to the apprentice school training only3 out of 30 in the never wear group were appentice school graduates Mr. Hutchinson would like to see all workers even auxiliary f workers who may be exposed wear some kind of respirator so that it would become a habit Mr. Brodie as chairman of the apprentice committee stated that they were presently working on a syllabus which should make the worker more aware of the hazard and how to reduce it They were looking towards a substitution of other products for asbestos where this was practical Mr. Horowitz said that it was very important that the asbestos worker be aware that a hazard existed Mr. Balzer pointed out that there is no correlation between apparent dustiness and count As a result it is impossible for a worker to tell whether he is being exposed or not Mr. Hutchinson said we are all being exposed to fibrous dust to some extent There is insulation lining the ventilation systems in most of our buildings He suggested that we should insulate the outside rather meme seve wn : i ; BL BL BL BL BL BL FL FL FL FL FL ! E- ft 7 wo Va Se tee ote ee eee Lg Sage yh eae Y . ONS a Mae Sentai} ae : UAE ee ai s k ee ae oa ct . re oe be Mat . we oe " Bote ee Se a ee . wee tee ao ot . . oo hey 7%! . ge rr - 16 than the inside of these ducts Mr. Balzer stated that he had found that the dust coming out ventilation system is usually not respirable Mr. Schall agreed stating that after a duct is blown out very little additional material comes out ( There was some discussion of the use of safety equipment including respirators by asbestos workers In some cases it was pointed out the worker was required to wear eye protection a hard hat ear plugs were desirable for hearing loss prevention and now he was being asked to wear a dust mask in addition The work was often very arduous the worker might have to work long hours where iit t was hot and uncomfortable Over the years there have been many improvements in hard hats but few in respirators Schtz Mr. of the U. S. Bureau of Mines than gave a statement which is summarized as follows The Bureau of Mines is of the opinion that engineering control of hazards is far superior to respiratory protection its It is expected that program for respirator the Bureau of Mines will intensify testing The Bureau believes that and expand respirators should be improved Present approval schedules are to be reviewed Those scheduled to be revised include 19B for air supplied respirators 21B for filter respirators and 13B for contained breathing apparatus Air line respirators afford a higher degree of protection than filter type respirators in general they are more comfortable and it is often recommended that asbestos workers wear air line respirators . Sees! syle, mone ' t _ At are ; hndienebe- pre's: eA guoene, f eae t e - Se CN % ae Oe ( ES. ce:Tee bam -: Sane rr taorr e an sald toe FRET ' Pr ee ae ee ee aa moe, ee te . See, WD WF we te . AN Sa ag Fe sy Sa DT oe ote ee? wn % ? ryPOTN .* eS woe ms OR at oso te ee aay t . fen tye4 ney ote, a . lee ee . oe \ yg . wee oe>b.ad 17 However there are limiting factors in the use of air line respirators such as the availability of respirable air and the hazards of a trailing hose By the use of pressure demand regulators the facepiece may be kept under a positive pressure at all times very much reducing leakage Air purifying respirators are more satisfactory from the standpoint of convenience but the facepiece is always under a negative pressure and leakage is therefore likely In the revision of respirator approval schedules greater consideration is to be given to facepiece fit It is recognized that a full facepiece offers at least 10 times the degree of protection because of better facepiece fit The revision of the filter respirator schedule will also provide for lower breathing resistance In discussion of Mr. Schutz statement it was brought out that there are no restrictions on air supply other than that the air must be respirable that there is no restriction on biologically active materials or filter media and that respirators which presently have Bureau of Mines approval do not normally have their approval revoked as requirements are changed Asbestos dust is approved as just another pneumoconiosis producing mineral dust Air line respirators are recommended because this is the general recommendation of the Bureau where greater protection is desired The Bureau does not develop respiratory protective equipment but merely tests it Although desirable it was agreed that air line respirators were usually impractical for insulation workers toms +: ryt ey. . aot wo eo myer wt 8 It was pointed out that the respirators are now approved for material with a toxicity no greater than that of quartz which has a TLV of 2.4 mppcf In this light it was asked whether all respirators so approved were safe for asbestos Mr. Ayer presented very preliminary data on efficiency of two commercially available media Both media showed filter efficiency greater than 99 per cent for either chrysotile or amosite Refering to this Mr. Burgess stated that if filter efficiencies are greater than 99 per cent then the limiting factor seems to be facepiece fit Practically it is difficult to do better than a protection factor of 10 for a filter type respirator Mr. Lynch suggested that we should aim at a protection factor of 10 in respirator that is acceptable to the workers We still do not know what is a safe level of exposure Mr. Balzer's data indicates that exposures are higher than the new British hygiene guide and this is probably true in Dr. Selikoff's population as well He asked whether protection factors of 10 could be obtained with unapproved types of respirators to bring in- sulation workers exposures below the exposures of manufacturing and also below the British hygiene guide Mr. Burgess replied that a protection factor of 10 could not be obtained with unapproved respirators There are however new low resistance types which will give a protection factor of 10 and be more acceptable In further discussion it was pointed out that worker education is necessary along with good supervision and examples of respirator wearing by supervisory personnel However though worker education goes . yd. gow 7 . _. vet satel -- we tat Ss See vv ne a RaesrTMeae etgatm oey cSSwSye,e ~ treswereese : Fa 4 Soe. 2 cael Mey ts < - 19 - a long way and can even be made a condition of employment there still exists the problem that respirators are hard to wear for 8 hours a day 5 days a week Even if employees are theatened with discharge they are not likely to wear them Discussion of potential improvements in respirators included lower resistance media better design design half masks with with pneumatic pneumatic seals and a a^' proposal for a revision of the resistance requirement to effectively cut in half the allowable resistance of filter type respirators Mr. Burgess presented a discussion on powered air purifying respirators These offer possible improvement in protection factors protection factors of up to 10,000 have been obtained in laboratory tests while still maintaining most of the advantages of the half mask air purifying type respirator A powered air purifying respirator is said to be available commercially The cost of this first powered air purifying respirator will be about 150.00 Noise of the blower is not a problem It was pointed out that in a recent reconstruction of a British aircraft carrier the wearing of full supplied suits was required for workers engaged in tearing out insulation It was brought out in a discussion that a typical situation was for about 50 per cent of the employees in any local union to stay with a job for 5-10 years The other 50 per cent of the Local moves from job to job (wemtan.. a 4 hs bet. f DAL DAL DAL DAL DAL aie ae ie Si a oS et opts, Oe ' Stet A, ke Pe er Sire ns BAU Se SE RE oe or han re bare - 20 - There was a lengthy discussion on the requirements of a good respirator program and its applicability to insulation workers In general the policy in an industrial respirator program is to issue a respirator to each man and to have it cleaned and maintained daily Mr. Brodie suggested that a respirator was a personal item of equipment It should be issued at the union hall and maintained by the man himself He suggested that a seminar could be set up for the training in the use and care a respirator Mr. Edmiston stated that a respirator was a piece of equipment which involved considerable maintenance and stated that a worker could not be relied on to maintain it himself The maintenance to be successfull must be done by trained maintenance * people and maintenance is required daily Mr. Brodie stated that such a program would not work on a construction job where men are scattered over a 400 mile area They do not even check into a common area daily Mr. Sheckler stated that the respirators must be cleaned and the filters changed daily and that each individual must have the opportunity to choose from at least 3 types of mask It is the contractor's program to supervise It is his responsibility morally financially and legally This must be recognized as a problem Mr. Burgess stated that three choices is enough for respirators but that the selection should be made on the basis of fit rather than of preference There was a considerable discussion of disposable masks It was agreed that disposable masks would be desirable and that the cost of the mask would probablbye less than the cost of proper maintenance Oa, , foray, at; erg x ws. 7 be nent | ee R SonT pe ET : tube. boo og : ey a ty to ye * , we cay ak coo oot pS - Me -- # . . eet? cas erat et ty oo - 21 - There was a discussion of a cost of a disposable mask which would be acceptable but no general agreement on what cost could be accepted The cost of a proper maintenance program for disposable respirator appeared to be prohibitive Mr. Hutchinson stated that present masks could not be worn on typical 2/3 if this were attempted jobs that production would Another suggestion was that be cut by conventional air purifying respirators should be issued and treated like tools of the worker An option between disposable respirators and conventiaonal respirators to be treated as a tool might be A suggestion was offered that reducing by reducing the offered to the worker number of hazardous operations , respirator use might be required only 10 per cent of the time For example if all prefabrication were done outside than dust 7 could be cut down considerably Housekeeping could be improved In addition to the insulation workers it was pointed out that other construction workers 1700 men on a construction are job also exposed to asbestos may have some exposure to perhaps 1600asbestos The specific need for respirator improvement were than discussed Mr. Edmiston stated that respirator manufacturers could produce any product as long as too many conditions were not set Therefore which is the most important point Mr. Hutchinson stated that the major problem is the closeness of jobs Insulation workers must crawl through manholes carrying pipe covering cement and other materials Their job is not comparable to that of a painter carpenter or other construction workers They are often working within a cluster of pipes with no room ) KL KL KL KL KL KL KL EL EL EL EL EL KL KL KL KL WS 7-- > % os ry rd @ * t i . Per oe weeyPre in vad SY >ee 2h Cog >etry >* y > rs OE TON A et . ww na oh tdwate . we ue Pig Tue oar * wae a Ee - - - 22 - ro for an supplied respirator Mr. Edmiston stated that requirements of a mask sometimes conflicted A very small respirator with a very efficient filter and a very low resistence was probably not within the state of art If the size of the filter is increased to decrease resistance than the size of the mask is increased It was generally agreed that small masks are necessary It was suggested that manufac- go turers to the jobs and see the problems It was suggested that an ad hoc committee of users and manufacturers be set up to develop the requirements for improved respirators for asbestos workers The respirators market for such would include many more than the 18,000 insulation workers in fact it was pointed out the 18,000 included only those who are members of the Asbestos Workers Union About 30,000 workers are in the trade Further sheet metal workers carpenters and iron workers do some insulation In the roofing industry there is also exposure to asbestos and perhaps 100-200 thousand persons are applying materials containing asbestos It was suggested that the climate for developing improved respirators has never been better than at present We are looking for a respirator which is comfortable and convenient enough to be made a condition of employment and yet that is efficient enough and fits well enough to provide adequate protection In the manufacture of filter media it was generally agreed that mineral fibers which could themselves cause pneumoconiosis should not be used The formation of an ad hoc committee was mentioned several times but the exact composition of such a committee or when it would meet was not decided } : PORK te we ax i AB wn te et or es atg a os. ce a : RP My WN ae Pe any h ee la : rl et tee * eh Taye et ak. es - 23 Mr. Ayer summarized the conference as follows It is recognized that asbestos dust if breathed in large enough quanities over a sufficient period of time can cause lung cancer and mesothelioma as well as asbestosis The development of such diseases may not follow a simple response relationship but is not completely independent of the amount breathed There is a considerable range in the concentrations to which workers are presently exposed and much would be accomplished if the higher exposures were eliminated It is agreed that there is considerable need for a generally accepted limit While it appears that the exposures within the insulation trade are generally within the present threshold limits the established TLV may not be too reliable since it was established in the textile industry where only chrysotile was used It was agreed that engineering controls at the job site combined with prefabrication might considerably reduce the existing exposure of insulation workers The effienciency of respirator filter media for asbestos fibers is not known at this time Respirators with lower resistance would be helpful in increasing acceptability so that they could be used to reduce the present hazards There has been considerable discussion of the formation of an ad hoc committee for the development of improved respirators to be approved by the Bureau of Mines Such a committee is encourged Participation of all present is most appreciated | 5a 2 owe fon F