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I Lancaster County General Hospital 555 North Duke Street Lancaster, ?A 17604 J. Kreider, M.D. Medical Director R/M Friction Materials Co. 123 E.' Stiegel St. Manheim, ?A 17545 Hilton C. Lewinsohn, MB., 3Ch., Corporate Medical Director Raybestos-Manhattan, Inc. 100 Cakview Drive Trumbull, CT 06611 MFCM(RCP), D.I.H. ABSTRACT The current Occupational Safety & Health Administration (OSEA) Standard for Exposure to Asbestos Dust was published in 1972. It requires medical examinations for preplacement purposes, annually thereafter and on work termination, or retirement. Medical records must be maintained and kept by the employer for at least 20 years. Medical surveillance must be provided for all persons in an occupation exposed' to airborne concentrations of asbestos fibers. The medical examination, as a minimum, has to include a chest roentgenogram (posterior-anterior 14 x 17 inches), a history to elicit symptomatology of respiratory disease, ar.d pulmonary function tests to include forced vital capacity (FVC) and forced expiratory volume at one second (FSV j. The format for the medical records is not stipulated, standard- 1.0 ization of the techniques to be used in obtaining chest roentgenograms of perform ing tests of lung functionis not required, and no guidance is given as to the methods to be used in the interpretation and reporting of results. UCC 023663 A02098 The legal obligation to provide medical examinations and a need to update the medical services at a friction materials plant in Pennsylvania provided an ideal opportunity to attempt to correct some of the deficiencies in the medical examination requirements of the OSHA Standard for Exposure to Asbestos Dust. This paper describes the implementation of a medical surveillance program which required the medical records to be redesigned, reporting procedures to be established for employers and employees, redefinition of the plant medical director's duties and the re-organization of the plant medical department. A standardized medical questionnaire has been introduced based upon the Medical Research Council's Respiratory Symptoms Questionnaire, the lung function equipment has been replaced by a new instrument and the nurses have been trained in their use. Chest radiographs, taken by the nurses at the plant, are interpreted by a consultant who uses a reporting system specially devised for the plant which will be illustrated in this paper. Guidelines have been prepared for the use of the plant physician when reporting the results to employers and employees. The annual physical examination is conducted by a chest physician (IDE or an associate) using a standardized form for recording the findings. At the time of the physical examination the completed questionnaire, lung function test results and x-ray findings are available (as well as the entire x-ray series) and the results of the preliminary examination by the nurses which includes blood pressure readings, urine analysis and haematccrit. Occupational histories form part of the medical record and we hope to enter the average annual exposure levels on the medical examination record. The decision as to whether an employee is being adversely affected by his work environment is not an easy one to make, but hopefully, utilizing the approach outlined, we now have a better chance of arriving at an answer. UCC 023664 A 1J 2 0 it -] 2,05 3 Finally, ve believe the OSKA requirements have been met and improved upon to the benefit of the employee, the employer and the physicians who have to attend to the needs of both of them. UCC 023665 A0210C /LC6> \ 11 <KaAPA'110;4AL DISlk , . earlier {A;/:. Luvir. !972. v. 24, fi-'9!. i ,. s'tl*;< -s wne divided into 6 prongs 0,1 'he levs -I::,- dust index aitd smokm v,-v.'-smokers v etc .rouped separated. Mt'kipfi- lr..-:-r repression to , a. ;,<* for lath oast exposure ft oup. taking into ...vims age. heigh! and weight, sc.iv calculated ani ..verage overall multiple linear repression lor the v'v.'.c sample was calculated by weighting the coiilti- b:.from each group l>y the information contained Cr. ;t. The resultant value was used to standardize, the ;r-.,.rn. function tests results for the different dust ,, /.Asure groups to common dimensions. Group n'cc-o values so standardized were compared with those of the adjacent dust exposure proup. The results arc presented in a series of tabtes wbi>.!v show that there is an increase m ace and a decline in wcighl with increasing dust index. The lower two du-t exposure groups could be distinguished by several of the lung function tests. Tnus inspiratory capacity, forced vital capacity and forced expiraloiy volume in 0'75 second and in 1 second were alt at'cetcd, although in smokers they were somewhat lev, sensitive as tests. However, it is interesting k> note that non-smokers with low dust exposure had tiw. best, lung function of any group. Any of the tests mentioned secured to be suitable for health surveillance of asbestos-exposed workers, whatever their smoking habits. G. F. Kcann^r 3252 Pilat, L.. Rafaiia, E., Ckacick. O., Tbculescu. D,, GEORaESC.Lt, A. M. & AvosTorx-ro', R. Contri bution a l'etude ties correlations entre les as;*.cts radiplogiqucx, ciiniques et foncuonnels icspirr-.lohvs dc l asbestose. [A ronlribuiion i<> the study of tin* correlation h,'tv,..cii riiitiv-lnH-'h clinical and respiratory fuiirliun aspects in nsbestosis.) A/rCuu Law, 1972, v. 62, No. It, 495-504. English summary (9 lints). ^ The 79 subjects studied in this investigation were employed in a factors' producing various kinds of asbestos appliances, including brake linings and jointings and filters for the chemical industry'. The. manufacturing processes gave rise to much dust up to 3 years ago, when measures to control it greatly reduced the dust concentrations. However, the authors do not quote figures because they were not satisfied that the techniques used lor the estimations were adequate for the purpose. The investigation reported therefore is limited to physical examination of the workers, which included radiography of the chest and a comprehensive series of lung function tests as well as a ciinica! examination ml a oiivfi.i aruminexi:.. Axhe-d'isis was cla^ni. . ir-t.o 3 stai:; -ir.lniuial. iitodart-tcly adt ariv-u fairly well dvanced--hav.- i on tin* ra>ii ti'.yic ! appearatue;. The rcs'.d's arc presenttd in a soies of tables, In 1965 .66. as a result of radiography of the cbcM. 3t! patients were jcoegni'ted as suffering from asbestos-' 18 of the;,!, wctc subjected to further radiography cf the chest in Pitiu and showed evidence of prey,1 essio:,-. Pleural ccl-.mention, which was rather extensive, v.as seen in I patient who had an exposure period of years. Dyspnoea on effort and productive cough were present in more than it::!! the workers examined and as II,e rathologica! category increased, short n-.:x*. of breath and cough were mote noticeable. A t obstructive ventilatory defect was closely reinvest to radiological progression and to deterioration it: respiratory symptoms. A genuine alteration ir pulmonary ddiuston. far front making an early and constant appearance in ashestosis as is commonly believed, in fact rarely occurs. Smoking did not seem to have a significant effect on the results oi the lung function tests. Ciinica! signs were fcv. and clubbing of the fingers wfas noted in only 2 patients and basal crcpitauons were heard in 1 singtj suhtect. /7*7a- G. F, Kemingc 325,3 l^wm^yi Z H. C. 't ile medical siirvf`dinner id H'b,. 11>- *vf-r ers. R. Roc. HUh 1972, v. 9i. Mu. 2, 69-71. The author reviews the historical background u> the present knowledge of asbestos-related disease and the development of current legislation. He des cribes the methods of medical surveillance in his own factory, the Rochdale factory of Turner tPutberr Asbestos Company. Here there at e over 900 employ ees working in asbestos-scheduled areas and a further 374 maintenance, quality control and laboratory work ers who are also exposed to asbestos. Medical art.tngcments for their protection start with an induction course and a training scheme far safe methods of working and the issue of a booklet outlining the need for the Asbestos Regulations and giving details of the diseases associated with exposure. Preemploymcnt screening is used to identify employees unsuitable for work with asbestos. Periodic medical examination* arc undertaken by the Pneumoconiosis Panel, aiternating with those of the Factory Medical Othccr. Annu.i! examinations are recommended for workers exposed fur 20 years or longer. The chest is examined by X-r.cy v.ithin 3 months of starling work and there- HCL 019538, aU2 i 0 1 ' ucc 023666 988 ABSTRACTS ON HYGIENE November 1972 after annually. The FEV1 is part of the initial medical examination, and a full battery of pulmonary function tests including estimation of the gas transfer factor is undertaken at 6 months, 3, 5 and 19 years and thereafter annually. The most striking finding is that after 20 years exposure more than half of the workers have abnormal radiographs, including evi dence of pleural thickening, and more tlian 30% have radiological evidence of pleural fibrosis. The transfer factor is also reduced in a high proportion of workers, hut this is also found in non-exposed new starters. The author emphasizes the importance of enlight ened management, an educated labour force and sound industrial hygiene methods for the successful medical surveillance of asbestos factory workers. This is a description of a most comprehensive scheme of medical surveillance which must be commended. It is a sobering thought that the survey by Mkrewether and Price in 1930 {Bulk Hyg^ 1930, v. 5, 562] showed evidence of pulmonary fibrosis among 30% of asbestos workers, and though the criteria for the diagnosis of this condition have changed. X-ray evidence of fibrosis is still present in 30% of workers in 1970. M. L. Newhouse 32.3 f Botham, S. K. & Holt, P. F. Hcvclimi-nt ul asbestos bodies on aitiositc, chrysolite and croci- ilolitc fibres in guinea-pig lungs. J. Path., 1971, v. 105, No. 3, 159-67. asbestos body were faster than with the other types of asbestos. Murid !.. /WvWtouir 32.73 Smith, Jl. A. it 1>,W|S. J- M. G. Tile- :<sM>r.i:tii<u> of pl*ngop.> io>ed a-ln--13 dii.-t niih Jysoc<inn* TMr,v,n,.s. jr. fVil/f.. I`>7). v. IDS, Nu. 3. 153-7. Granulomas were produced by the intrapleural injection of chrysotile asbestos dust (25 mg) into the right lower thoracic cavity of guineapigs. Animals were killed at 2 and 4 weeks after injection. Pieces of the granulomas were fixed and sectioned for electron microscopic examination, histochemical methods being used to stain for acid phosphatase. The Gomori technique reveals the presence of acid phosphatase as deposits of lead phosphate. Acid phosphatase was demonstrated only in the lysosome series of organelles but not all of these structures gave a positive reaction. Usually less than 50% of the lysosomes in the macrophages and giant cells gave a positive reaction and often fewer than 10% of the phagocytosed dust particles were in structures tint gave a positive reaction. The few fibroblasts in the granulomas usually contained a small amount of chrysotile dust and then both primary lysosomes and dust-containing phagosomes usually contained acid phosphatase. There was no satis factory evidence for the rupture of phagosomes and subsequent liberation of the lysosomal enzymes into the cell cytoplasm. P. F. Holt Guineapigs were exposed to chrysolite, crocidolitc and amosile asbestos for a short period at the begin ning of each experiment so that on death the length of time which the fibres had been in the lung was accurately known. Anthophyllite asbestos had been studied in previous experiments [Abstr. Hyg., 1969, v. 44, abstr. 621). On inhalation of all types of asbestos the fibres were distributed throughout the lungs. Some fibres of all types were ingested by macrophages and Perlspositivc material derived from red cells was deposited on them, but some intracellular fibres remained un coated during the year after dusting. After a further 6 months uncoated chrysotile fibres were not found, but a few anthophyllite and rather more crocidoiite fibres remained uncoated white uncoated amosile fibres were common. The morphological development of asbestos-body coating followed the following sequence: smooth, corrguated, partially beaded and fully beaded. The development and fragmentation of a chrysotile 3256 Ministry or AcHtcutTimn, Fisheries and Food. Working Party on the Monitoring of Foodstuffs for Heavy Metals. Second Report. Surrey of lead in food. 31 pp. 1972. London: H.M. Stationery Office. (2Ip] 3257 Vaskov, L., Hatdlska, A. ft DrrCHEVA, T. Ndphrographic radio-isotopique chc/ dec travaillcurs exposes k un risque d'intoxication professionnelle par metaux lourds. [Radio-isolopic nephrography in workers at risk of ocenpatiunal poisoning by heavy metals.] Arch, Mai. Pro). Mfd. Trav., 1972, v. 33, No. 3, 107-12. English summary. The authors present the results of a study of 58 workers at the occupational diseases institute in Sofia in which they considered the possibilities afforded by a radioisotope technique of demonstrating if or how renal function was affected by work with heavy metals. The method (to which references in the literature are given) of registering tracings of radionephrograms after the intravenous injection of sodium A U 2 U '3 UCC 023667 ASBESTOS - A Bjftrigrf 0? HEALTH SAFEGUARDS. by H.C .Lewie 3-^ji. Talk to the Institutlah-tf Zi*i .i'yt.al ?*$. ' Officers on I1. )..'' It has been stated tha~ Asbestos has bee-, in isa for at least 2.500 years. It was said to have beso wrren L-jto the wi:-ks of the 1 perpetnil lamps1 of the Vestal Virgins, ai;d the linim vivnm used by the ancient Homans for cremation cloths was made cf asbestos. Marco Pole came upon asbestos nines which were probably tV.se known to Save been operating in the Russia of Peter the Great, ar.d in the 15th esntury there was ar. account of asbestos being used during the siege cf Rouen in 1420. Until the end of the 17th century asbestos was mainly an object of superstition and curiosity. In the mid .nineteenth century, with the discovery of serpentine asbestoa(or ehryaofcile}in Canada, the emphasis was placed on conservation of heat by lagging rather than resistance to fire. All known deposits of the mineral were of the chrypotile variety until a German geologist named Iichbausteiz. discovered a mass cf heavy asbestos of lavender blue colour near Frieska in the Horth-West Cape Province of South Africa j this is the famour Cape blue variety, which was first exploited in 1391. South Africa, is the main source of blue asbsstos(croeidolite), although deposits also exist in Australia, and elsewhere, and have recently been reported in the iron formations of the `labrador troughs * of Canada. Amoslte, a fawn coloured asbestos, was subsequently discovered in the Transvaal, and these deposits ere thought to fce unique in the World. Anthopfcyllite, a magnesium silicate which differs from ehrysotile in being le3s soluble, is of lass ecjmnerciaj. Interest than the other three types, but of considerable medical interest. It is mined principally in Finland and Italy. Table 1. in Gilson's Wyers Memorial Lectare(l965)eujiMsrlsss quite adequately the statistics relating to world production of the various typos of asbestos and their composition. The dangers of asbestos to man have bea in the news - both in the medical Journals and in the lay press, A brief review of the present situation in the light of this interest would not be untimely now. In 1930 Merewether and Price published their "Report on Effects of Asbestos Dust on the lungs and Dust Suppression In the Asbestos Industry" at the Instigation of the Factory Department of the Home Office. The first case recorded "about whom there was expert opinion that the inhalation of asbestos duet had at least contributed to, if not caused, the fatal outcome" occurred in 1900 and is new referred to as the "Montague Murray case". Dr. Montague Harray gave evidence in 1906 before the Departmental Committee on Compensation for Industrial Disease. In this case post-mortem examinations confirmed the clinical diagnosis of extensive nan-tubercular pulmonary fibrosis. The second(Cooke's case) occurred in 1924. Here there was a contribution of "a progressive dust, fibrosis together with a chronic tuberculous infection". Following the discovery in February 1928 of a "case of nontubercular fibrosis of the lungs in an asbestos worker, of sufficient severity to necessitate treatment in hoapital^.Seiiar'e case)" an inquiry was ccmaariced by Merewether and Price. In their words "When, therefore, investigation of Seiler's case showed that other industrial and infective causes of fibroaia couiu De definitely excluded, the necessity of deciding whether the supervention of this disease in an asbestos worker was an exceptional occurence, or evidence of a grave health risk in tha industry", was apparent and the investigation referred tj was undertaken. A 02103 contd. flO- 0191^6 UCC 023668 Merewether and Price examined 363 s workers, They United tivir Investigations to those processes i* wll..'h there ws eapcy:.re to p:v*s asbestos or asbestos mixed with a v-wy snail pvrrjec-.tage of ttor. or ciiar vegetable fibre. Processes i'.vtvlviTg at onjoaire tc mixed duets Unlading asbestos wsra not investigate!,, si.v^e 1` was felt that is va? set possible "to evaluate the effect on tee iaig? of missd dvd-, of whi-ii asbert-sa dust is only one component, 'ar,ii_ tie acute?. >f asbestos dust i':9eif wa? determined." The worker -. `xamined were from tie text!-* brst.-h of the iridij-iry, manufacturing insulati;.^ -ji-6rials from practically purs asbestos. This inquiry led to the 'OE.c.lisii.n that "the inhalation *f asbeetc-s dust over a period of years results .in x-he development cf a serious typa of fibrosis of the lungs". They found that 95 -of the 363 wxricers ;.26,2^3sbcwed a definite fibrosis due to asbestos dust. Of rhs 133 who w=re X-r3yed 62 presented radio logical signs of a diffuse fibrosis and tr. a further 25 tfcsre were suggestive radioing! sal changes not definitely diffuse fitrv sis. Meravratiter found that one In four of the sample of 363 woAers <*mmin.Ai had evldar.je of pulmonary fibrosis attributable to asbestos duet ana he calculated that <*. the sample, one in eight of all workers in the ir.duL-t.ry **ould be found V. have evidence of fibrosis. The findings with regard to the incidence of fibrosis in relation to length of employment were modi significant ai-.d the results are given. Here it is demonstrated that length of employment and not age was the major factor in the production of fibrosir. The report contained 12 recommendations listed as follow : 1. Application of effl' tsnt i.e-'a-ifted exL'attsf ventilation and dust producing pc.int3, 2. Substitution of enclosed aechantual mstbeds for hand conveyance, and for dust hand work generally. 3. Effective enclosure of oust predu ix;g machines and plant. 4. Substitution of wet methods for dry. 5. Elimination of certain dust prodtrlng appliances. 6. Abandonment of settling -liMbera in iaar.'ifacturing prttessas to the utmost oxteifc. 7. Effectual separation cf psujesses tc prevent unnecsssaty exposure t-o dust. 8. Wide spacing of dust producing machinas in new factories and as far as practicable in tod.3tirg works. 9. Ose of sacks of loose texture material for internal werit. 10. Efficient cleaning systaa with wide use of vacuum method*. 11. Storage of asbeatca ar.d other de to be outside vorkrxjme. 12. Exclusion of young persons from specially dusty work. Legislation followed in 1931 sjr.d regulations were made fer the control of the hacard during rniaufacturing processes which were embodied in the Statutory Rules and Orders, 1931, N0.H4O. The parts of fau'-c-Tie? in which the Asbestos Industry Hegulaticrs 1931(3.R. and 0.1931 Kr.liAC) apply were scheduled in the official dcreceet and ars new generally termed 'scheduled areas1. They comprise areas fer the operations of c rushing and opening, textile processes, insolation fabrication, mattress making or r apairing and all sawing and grinding. It addition cleaning cf chambers or appliances for asbestos dust collection were included. Under section 79 of the Factory and Workshops Act 1901 the Secretary cf State issued a certificate tc the effect that "the manipulation cf asbestos and the manufacture and repair of articles composed wholly or partly cf asbestos and processes incidental thereto are dangerous". The section in the Workmen's Compensation Act of 1925, which provided for the application of that Act to workmen suffering from sillcoals, was extended to certain. TM,'v-*ses involving exposure to asbestos dost, and In 1931 "Aabeotosis"b^taaw a eompensatable disease. For the better care of the workers in ' Scheduled Areas they were subje ct to initial and periodic examination, annual at first, by Medical Panels alloyed by the Heme Office. Workers found to be suffering from asbestos fibrosis were suspended from farther work iu the industry and compensation payaaita were made to these fearsi suffering from the disease. There, was no appeal (oc the question of diagnosis }froci the decision of the Ksdioal Examining Board. Coroners in Great Britain were instructed tc enquire contd. m02 I 0^ UCC 023669 -3- into the deaths of asbestos -workers in rases where they had been appended from work on account of pulmonary disability or when their length of service rendered it likely that their occupation was a contributory cause of death. In all suspended cases, and in most of the others, necropsies were performed and pathological material was thus provided for study. In 1935, lynch and Smith in the tfcited States, suggested that patients with asbes'^?is might be exposed to an increased risk c-f lung cancer : and by 1955 Soil it. this Country had demonstrated a tenfold excess of lung cancer in a group of asbestos textile workers (T.B.A. Rochdale)with 20 years exposure or more . In this factory chrysctile was predominately used, but some exposure to crocidolite may also have occurred. In a subsequent report in 1964, Khox, Doll and Hill presenting a follow-up of this saw population and these entering the saas factory after 1933 when the Regulations came into effect, now stow that the vigorous action taken then, and later, to reduce dust levels, has been largely successful in eliminating the hazard, though a further period of observation is necessary before complete success can be claimed. The Annual Report of H.M.Chief Inspector ot Factories on Industrial Health 1966 brings up to date the evidence(obtained from death certificates recording asbestosis) of the association of pulmonary tumours with asbestosie. The 1964 report notes, that "It is possible however that the percentage of death certificates recording lung cancer is exaggerated by the current acceptanc of an association even where the asberiosis present is minimal. A former asbeato worker dying from lung cancer may have a she-steals diagnorod for the first lime at autopsy11. The current interest in asbestos stsas from the growlrg evidence of an association between asbestos exposure and the occurrence of the relatively rare tumour known as mesothelioma, which may occur in either pleura or peritoneum. Doll in his Rock Carling F6HrwBhip(l967)mDnograph on "Prevailtation of Cancer" notes that, "This condition is normally ao rare that, even a small absolute risk can be rapidly detected once it has been envisaged". Approximate] 300 cases have bow been described, the great majority in South tfries and the United Kingdom. In soma eases, both in South Africa and Britain, this exposure has been environmental and not occupational and asbeatoels has se_aom been present. The answer is not clear as to why it occurs in people who might have had only slight exposure many years before. Some cases may nave occurred and not been recognised; but the mors important reason would appeal1 to be the long induction period of approximately forty years that characterises the condition. Few of those who were heavily exposed prior to the introduction of preventive measures can have survived long enough to develop it. Certain authorities, mainly in the United States of America, related mesothelioma to chryeotile exposure alone, but it is now believed by most reliable investigators that a pure exposure cannot be proven and many of the cases of alleged pure chrysotile exposure had in fact been exposed to mixed asbestos varieties including crocidolite. In Sooth Africa the experience of Wagner has been that large numbers of cases have bees described only in relation to blue asbestos. In the H.B.Cape Province,110 cases have been described from the c rocidolite area, cone in the amosite mining area of the Transvaal and none in the chrysotile mining areas in Swaziland. Whether lung cancer Is also produced more easily by croeidolite remains to be show. The difficulty in this case is that the risk of lung cancer has been demoastra in relation to the use of asbestos and not to its mining, and asbestos workers have seldom been exposed to one type of asbestes alone. It is clear however from British experience, that a high risk of lung cancer can occur vfeem the asbestos used has been almost wholly chrysotile.(Doll 1955} In order to assess the risk of mesothelioma, epidemiological studies will have to be undertaken to investigate populations, either industrial or residential, exposed only to one type of fibre. Such exposures are almost entirely limited to those engaged in ad ring and Billing of fibre, which is done in the countries where the different types of asbeetos are found. The International Union Against Cancer (U.I.C.C.j has given an important lead in this work with its report of an international working party, and the UCC 023670 &02 i(tt contd. Union has sat up an international ccjmLt' ee to help impisssent the recommendations of the working party, and to bring together worker9 t> many countries at the planning stage of their research. What are the measures which the industry adept tc improve oo*_a.i"ion?, and why, in spite of these measures, has the incidence of asbesbcsia increased steadily rather than declined ? If lurg cancer Is a risk car this be controlled by the measures adopted ? la the incidence of asset*-elioma controllable as well ? The industry has unfortunately not been covered as & wbrle by the Asbestos Industry Regulations. Mere-wether & Price did not cast their net widely enough, sad it was not really appreciated until recently that users of asbestoB products were as much at risk as asbestos workers themsalTr*:of the safety precautions recommended by the Asbestos industry Repiiaticrs and the Codes of Practice prepared by the Asbestos Industry were not adhered to. The insillation industry which is concerned with lagging, with asbestos eeansnt products, with asbestos spraying and the use of numerous prcd-det? incorporating asbestos iB non governed by the 1931 Regulations. Ne regulations have yet been introduced for the handling of asbestos products for thermal insulation, although it is accepted that tc eliminate the risk of asbesteels all practical steps should be taken to minimise the.inhalation of asbestos dust. The Asbestosls Research Council has produced Codes cf Practice for working various types of asbestos products used in thermal insula.g. loose lagging, pre-forasd materials ar.d sprayed insulation), ftr stripping materials containing asbestos, the use and care of respirators end t-hi medical supervision of workers. Another code wavers the handling, wnridng and firing of asbestos and aobestoc--cement products in the building and construciica industries. Since it has been suggested that mesothelioma can be caused ir. certain cases by quite limited exposure to asbestos (possibly even ncci-occupational) and there is evidence that the main risk is associated with blue asbestos (croetdolits)it is important, to take all possible precantiois tc reduce this risk. Of the three main types of asbestos imported into Britain last year, 93^ wa3 white asbestos(chrysotile) ,UtJ% was aarsite and 2^% was blue asbestos (crocidollta). Blue asbestos is mainly used because of its acid properties and is not used any longer in asbestos cement products or sprayed asbestos insulation work. The safety of the worker can be best provided for if the procedures in the A.R.C, Codes of Practice are adopted when ever asbestos products are used. The employer may do all in bis power to ensure the workers safety, but the ultimate success of the effort depends upon ths attitude of the man at risk and his willingness to work within the safety regulations. It therefore falls upon the employer to monitor the working environment, to rectify d&st producing processes and to provide the most modera ar.d up-to-date methods for dealing rapidly with dangerously high dust counts should they arise. There is as yet no universally accepted ne-rdnml allowable concentration of asbestos dust, and engineers, doctors and research workers are striving to determine f rom the incomplete information available tfcat level of dustiness can be considered safe. The only Information they have had to rely upon in ti? c.' avtry is what has been provided to the British Occupational Hygisne Society by a large asbestos textile factory where the relating of dust concentrations to morbidity has show that in certain areas with counts below a certain level ths Incidence of asbestomis disposed clinically with the stethca -ope has steadily decreased as dust counts improved. It is hoped that a rsocannaadation by the B.O.H.S. based on these findings will shortly be published and that this will become the K.A.C. The present MAC which is given as 5 million particles per cubic foor or 187 particles per e.c. is based on w-* findings using the Greenburg-ahdth impinger testa which are not standard practice in Britain. It is not ay intention to discuss dust counting methods or instrojasnta except in the simplest terms as I am not an authority on these matters. Addingley(l966)acd Holmes(19&5) have described ir. their respective publications , CMtd, a a 2100 UCC 023671 -5~ just those detail*. Most of the stir.d&rd. types cf its'-itaei-v used with, asbestos arid are listed below : s be_ 1. Owens 5t counter - This is of walue- in taking eos? eaafiej. Insuffi'.l. . 2. Krmimete-r - designed for snap 3. Thermal precipitator - offijdautj* fells cff f'.'r log ashes-. particles. 4. Orsershiirg-Sraitii impinger -p-trii?;. Oily a ' poor V- fair-index of oTposure 5. Hear.. it. filter methods. 6. QraTiiaetrio methods. 7. Tyi.aaiiaiMt.rirt methods . Ie the factorise X work it, the membrane inter method ar.d a fyniaiionetri method using the Rcyco photc-elsctrlr particle counter are used together. The Royoo instrcBMCt enables Mush more efficient routine testing to he carried out than has been possible previously. The memortoe filter provider a valuable cheek and is also useful for mixed dusts. The Itadtatioiss of the Royco are that it counts all. particle* which pass through provided they art big enough to give a signal. H the rang* from 1U upwards, tty error due to normal atmospheric pollution is important, ar.d in cl-. 4u upwards sirre range is negligible . The Hoyco is therefore suitable for dust t6si in any ordinary asbestos textile operstion. In some operations, however, such as automobile brake lining manufacture other organic and mineral dusts are present along with asbestos, and under such circumstances the Boyce will rectrd the to- al dust count only, and other methods must be used to estimate the asbestos. Merswether said : "While it seeme necessary for the pc-rd: -tic:; of general ised fibrosis of the lungs that a defiaiie rduimai quastity if dust must be inhaled, the lower the concentration of dust in the air breathed, the larger the lapse of time before fibrosis is fully developed, and within a certain limit the higher the concentration of dust, the sooner the fiticsl.s become?. folly developed and the more intense the involvement of the lung l-issue. If this hypothesis is correct, and the evidence points to it, the practical inferences are of very great importance, since it fellows that the applicaiin: rf measures resulting in the reduction at the concentration of dust ir_ the air in neighbourhood of dusty processes will cause, firstly, a great in .reass in the length of time before workers develop a disabling fibrosis, ar.d seorn-ty the almost total disappearance of the disease, as the measures fur ths suppression of dnst are perfected n. Nearly 4D years later these words need careful consideration once again in the light of the increased ir.:ichsv:e of asbestosis end its complications in workers not protected by the 1931 Regulation?. New Asbestos Regulations are being formula!ed at this very moaait and the advise of the Factory Inspectorate, the various interested medical bodies, the industry as a whole and the trade unions has beat to aid in their preparation. It is hoped that the new Regulations will include r.ot only controls to be instituted by manufacturers of asbestos products, bat also safeguards for users. The 19JL regulations do not take into account the different varieties of aabestlforsi materials and ths evident* to suggest different biological effects for each. The Regaintix.s do not suggest a M-dimm allowable concsitratior. for asbestos dust in the working environment and make no mention of medical arrangements for select!or. and follow-up of scheduled workers. If in 40 years time we are golzg is have to admit once again a lack of comprehensive control, then these deficiencies will hare to be corrected in any new regulations. The New draft Regulations lay much stress upon the use cf respirators for various purposes. Herevetier stated that respirators provide only partial protection and "there is a real danger that the use of them may give a sense of false security". Respirators cannot be said t* be valueless but can only be regarded as a second line of defence and an admission of defeat of dust control precautions. Under very exceptional circtssstantes there nay be scope for the use of the efficient type of breathing apparatus comprising a mask or helmet with a fresh air supply. The air supply may be by air line from a compressed air source providing filtered air or it may be from tie environment passed to a face mask by means cf a powerful fan a^d -SAder positive pressure, thus enabling the mask fitting to be looser because ccnd. UCC 023672 A02 i 07 leakage does not natter. The pcwer padk car ce wtri. on the workers cati acd does awqy with the c-i for Treat air fe.>ses whi-t in themselves "Oneiitnte a danger on building rites etc. Tie Marjiiactcrers rcs.oen.fd. ar* at present, developing a Positive Pressure fireeh Air Respirator ac-d this \v< ter?. welcomed by the Factory Department,, th6 writers and toe irdcrtry. lie Asbestos!? Research Gourdl has isaie-1 brief re-jucmec.'iari.ors c-r. the "Use and Cara of HaejLrato: Respirators ahmid be worn by all empioyuee at ail Mir i Wen : 1. Spreyirg asbestos and feeding hoppers on sprayed asbestos 't.rit. Respirators should be worn by both operator and attendant- duri/.g the f*sll peri.r that work is being carried out and by any employee raarinirg in the dusty atmosphere for a limited period after spraying operations have teninatei. 2. Carrying out the following operations which, t&wsrer pc.tib.U, should be carried out in open spares where there is a free cioauation of air a) The dry mixing of any material containing asbestos (this optretion mast be carried out in segregated areas if poasdile) b) The aixLcg of compositions and self"Settirg ceaeits hire an. asbestos content. t) The ."leaning and emptying of setks ci- ether vor.-t iin.r:v'J --.i contain asbestos or an admixture of asbestos. '.here the above operations are being carried cub ir. cc>. fired space# adequate arrageements must be made for ventilation. 3. Carrying out the fallowing operatict.e a) The cutting of all insulation materials eoatairJrg tstertod cr aa admixture of asbestos by hand in ecnfir.ei spaces, t) The cutting cf materials containing asbestos or sc sdaferitre c.f asiest by portable or ether power-driven. saws or similar to I?. c) The breaking dow for raanvfl of lagging cent si_.irg asl cstcs cr an admixture of asbestos. The approved respirator should fce carefully maintained, asc! adeqtat-c servicing arrangements should be madr to er.eure that this is do.ee and that employees are not without respirators iurltg maird auacce. The Medical Supervision of wurksrs in scheduled areas if at pcosest the prerogative of the Pneumoconiosis Medical Panels cf the MLvlcl-y of Social Security under the Silicosis and Asbestos! (Medical Arrang^!osits''S:heme 1931. There is little doubt- that this scheme has failed to use the results of the medical examinations system and dust assessments from industrial processes to keep a watch on the asbestos industry as a whole. In his Wysrr Manorial lecture Dr. J.C.Gilson, asks for a properly integrated soneae in which infomation about groups of Individuals and their dust eap'.sure is analysed to provide a continuing check on changing coalitions in the industry. The Asbestosis Research Council reoonmend the following siaae for the Medical Supervision of Workers s 1. All employees should be examined clirically and ra-dto Irgically before employment or as soon as possible afterwards, a artafriTy vit>.ir. three months to avoid the employment of who may be parii .i.-a.'ly sasoepiihle to the hazard. 2. Periodic examination should be made thereafter, -vruv-j Ki.I? If possible 3. Notes on the Medical examination of Workers in the A?fcest;s Industry are available as a guide to doctors concerned. 4. New employees should be advised of the precautions necessary in the industry. 5. A system of recording the employment hist-cry of workers Entering the Thermal Insulation Industry or who have been employed in the Insulation contracting industry would be beneficial. To the above I would add a sixth recommendation : 6. Examination of ar.y personnel >feoas regular duties bring tlea in daily contact with asbestos workers haadling asbestos material_* e.g, Joiners working in the proximity cf sprayers, elsciri -'.ana wrrkicg where laggera are using asbestos, etc. etc. These "nco-aibestos workers should observe all the precautions reconsnended for scheduled workers. The diagnosis of asbestosis ia at present made by the P.M.P. who have th> power to suspend a asm fra his Job. The early diagnosis cf asbestosis is mor frequently made by the industrial medical officer. The P.M.P, only see worker UCC 023673 A 0 2 i C: 3 every 2 year* and their periodic medical examinations do net ini-ids routine X-rays or lung function teste. Thera is good evidence to figgset th.it asbestos induced changes in x-rays and lung function teats may precede otter diagnostic crittra and it is for this reason that efforts are being concentrated open these two fields to enable standards for early diagnosis to be sstalHshed on an international level. Hunt of Cleckheaton believes that asbestos workers with lung fhrctioa deterioration detected at- an early stage should be iamedia ..removed from ejtposure, Ha believec chat the cccr so ci its disease in men tii- -e arrested, even regress slightly, and certainly preg'-iec at:!; ore slc-_y. Many questions remain to be answered and much aware effort will be require on the part of all concerned to make it as safe to work with asbestos as it is to work with radio-active materials. ffegir.eers have a great part to play in desigring plant which dees not permit the escape of asbestos dost ixtc the working environment or into the general atmosphere. Epiiei^ologists and statisticians have yet to determine the threshold Haste va.u-.* for asbestos. Medicine has to fathom the cellular and irtra-jellalar react!333 t* asbestos and to determine what controle the processes of fibrosis, malignancy, and insnunity. There is certainly an immunological factor as astcy workers never contract the dieeaee whilst others do so readily. last but not least it is to the Safety Officers ard Tiitest-rial Hygienists that the task of supervising the proceeees and enforcing safetyregulations falls. "Hercules himself most yeild to odds : And many strokes, though with a little axe. Hews dewn and fells the harleet-timber'd oak. King Henry VI. part. 2. Act. 2,5 :.l, William Shakespeare. UCC 023674 A ;J 2 1 0 3