Document DGKYJopjdakmedprz8Mg5n0gM

REPORT OF THE Commissioner of Public Health for the year 1959 Presented to both Houses of Parliament / Appendix Vili ADDENDUM INDUSTRIAL CHEST DISEASE I.--EASTERN GOLDFIELDS This report if ooaoerned, mainly, with the result* of the periodical examination of miner* end #x miner*. Many more miner* have voluntarily submitted themeelvee for a clinical examination, in addition to thoee who are under epecial supervision. Viaat* were made to Wittenoom and Noreeman to examine worker* clinically, in association with the Minee Mobile X>ry Unit. Hie reeult of the examination* during 1969 are a* follow* i-- Total number of Chest X-ray examinations ............... Total number of eaeee of Silicoeie .......................... Total number of new eaeee of 8ilicoeia........................ .. Total number of eaeee of Active Pulmonary Tuberculoeie 7,269 669 71 10 The figures below are the reculte of the periodical examination* since their inception in 1925-26 to 2968. It should be borne in mind that not all miner* are X-rayed annually, eo that yearly totals are not an aoeurato reflection of the incidenee of lung disease in any one year. TabU XX RESULTS OF PERIODICAL MEDICAL EXAMINATIONS OF MINE WORKERS FROM INCEPTION OF EXAMINATION (1925) TO 31st DECEMBER, 1958 Tsar 1926-26 _ 1927 -- ' 1928 L * .... 1929 * 1930 _ . 1931____ 1932 _ 1933 -- 1934 __ 1935 1936 __ 1937 1938 . 1939 1940 __ 1941 1942 _ __ 2943 __ 1944 1945 __ 1946 1947 1948 -- 1949 1950 1951 1962 1963 2964 _ 1966 1956 -- 1967 1958 . -- Total aamber ti esta&isatiQBB 4,023 3,728 3,483 . 2,688 . 3J99 3,012 4,236 3,377 6,663 4.808 7,363 7,852 7,141 6,976 7.299 7,141 6.824 4^98 4.468 3,334 6.606 6,460 6,134 6.489 6403 6.721 6.969 6412 6,279 6,606 6,476 4.811 6486 Total aambsr of sOieom* case* diagnosed M2 474 - .460 420 400 399 .426 439 406 364 372 362 296 292 268 294 350 367 376 266 300 396 298 314 349 305 294 366 487 497 474 483 682 . New seas*' of aHooric (pvTfooalj aormal or finear markings only) 642 41 62 102 138 94 36 68 66 36 30 IS 13 18 12 32 61 63 70 54 90 101 24 24 14 13 9 80 168 70 30 34 54 80ico.taberea)oais sad Tabsrculeau without SQisosis 142 138 46 48 . .164 " 83 '.24 18 1? 19 13 12 13 8 5 9 14 < 12 33 9 12 12 12 12 3 10 5 9 10 8 174,093 12.837 2,331 947 These result* are disappointing and it would appear that there ha* been little significant improve ment in the incidence of industrial chest disease for many year*, despite the great advances in medicine, engineering, ventilation and working conditions. The totals only refer to miner* and ex-miners examined under the Mina<Wq}ter**. Relief Act and some examined for re-admission certificates under the Mine* Retru* lation .Act. They do not, therefore, contain all the cases of silicosis and/or tuberculosis attributable to the mininc industry. Although l'1 new case* of activ* pulmonary tuberculosis are recorded as being diag nosed in 19.'9. there were actually 24 eaa*n, if men w:.. have left the industry and w*re outaide.the scope of the relevant Mining Acts are included. Some may also have been diacuoaed elsewhere and not bronchi to our notice. It is hoped that the intensive follow-up and investigation of miner* with abnormal iiiwt X-ray* will reduce the incidence of tuberculosis soon. Thu u a pious wish which has probably been repeated annually tines 1920. It would appear that one worker out of every 60 who entered the industry contracted pulmonary tuberculosis and even today the annual incidence is 2 per 1,000. Fortunately, with the modem treatment* available, even in the presence of advanced silicosis, successful treatment of the tuberculoeie is almost guaran teed. 46 la regard to silicosis, the function of the periodical examination of worker*. *a conducted here, ie mainly diagnostic, prevention being regarded as an engineering problem. One worker in every 30 who entered the industry developed silicosis with an annual incidence of 10, per thousand. It is not poeubie to determine what percentage of silicotice, recorded, subsequently appear in the last column as having developed tuberculosis. A frequent criticism made to account for the variation in the number of new caaee of diagnosed annually and the continued high rate is that the diagnostic criteria vary. There is some truth in this criticism. With irurnTpal radiological silicosis a subjective error is prceent but thta usually only result* in anticipating or delaying the diagnosis for a few years and the effect is cancelled out. Chest X-rays dating back to 1936 and clinical record cards containing the diagnoses made at the time are available and reappraisal of the films does not suggest that the diagnostic standards have varied grestly. Improved X-ray technique, high definition screens, dual film reeding and comparison with standard films from the Pseumoeonioeis Research Council are probably enabling s diagnosis to be made at a slightly earlier stage than hitherto and this is most desirable. If the diagnosis is in doubt, complete investigative facilitiee, including lung function tests, are available at the Perth Chest Hospital and ever increasing use is being made of these facilities. Statistical analysis of the results is most difficult, if not impossible, because miners and ex.miners are examined under several different Acts and because of the large number of itinerant and short* term worker* in the industry. Australian Blue Asbestos at Wittenoom which has been in full production for a relatively short time presents s different problem and has been the subject of a special report. A report on the health of miners would not be complete without introducing the question of the miners general susceptibility to respiratory infections, particularly chronic bronchitis. It is extremely difficult to apportion pulmonary disability between silicosis and chronic bronchitis. Chronic bronchitis almost invariably accompanies silicosis but occurs equally commonly without any evidence, whatever, of silicosis. It is a disease associated with heavy industry and air pollution of which silica dust forms only a part. . Oust, fumes, artificial working conditions, lack of sunlight, changes in temperature and humidity, cigarettes,. alcohol, all contribute. The system of ventilation, which at'times direct a stream of cold air on a man perspiring from over exertion, may also contribute. At the pre-entry medical examination all applicants for initial medical certificates with evidence of bronchitis `are .excluded and miners who develop suggestive symptoms , are strongly advised to leave the industry. Intensive research is being conducted in England into this particular problem and further developments will depend on the outcome. INDUSTRIAL CHEST DISEASE II.--WITTENOOM Periodical chest X-ray examination of workers in the Asbestos industry during 1959 disclosed no new cases of Asbestosis, although there are several men whose X-rays must be considered suspect. Those whose X-rays are considered suspicious of Asbestosis will be examined again in 1960. The length of exposure of workers contracting Asbestosis or Silicosis is much shorter than comparably . employed men in the gold-mining industry and the extent of disease is greater. The small numbers of t. workers and the extremely high labour turnover make this leas obvious. There are a number of puzzling and disquieting features. In several instances Asbmtosia has been diagnosed in underground workers although the disease had been considered peculiar to the Mill. One member of tbc train crew underground, not usually a great dust risk, has what appears to be a mixture of silicosis, asbestosis and possibly tuberculosis. Another underground worker has what appears radiologically to.be pure silicosis, but his sputum contains asbestos bodies. The Mines Department has permitted me to inspect the results of their periodical dust counts. It is obvious that the new Mill is a great improvement on the old Mill and that conditions underground have alao improved. It is too early to tell whether the new Mill will be responsible for fresh cases of industrial cheat diseases or not. The disquieting feature about the dust counts arc two fold ;-- . 1' The rock mined ;s apparently highly silicioua him therefore particularly dangerous. The dust counts are 'ii par with the figures for the gold mines, a higher standard be set in view of the high silica content and the additional Asbestosis risk. - (3) The dust counts are -.{ partoniy ; the same instrument is us-d for detecting silica par- w'3`- qn.i .fc,)--<io Th-.dangerous par iole size in .'vl:-- 'than "* n ; in Asiv--.- la-.g-r ::* t:br- >r.irh is r. J'> and 4'* r:.. r u- J'b- " :heret.r*- .r- h;:i- vain** they -h.c.v - f :ibr*- ;.t `hat c*1. The Kvi.unvter ;n * .n .'date ,s :;.>t regarded a* an -if'-riv- .ristrun'.ent : r fist the *;.s industry ;:i '.i::ada. A :r.::g-t Inuingef It vr- -*'*d :i; r- > v-r I < m a .r- *t y.ur*.ar unp-rtance .tivi \vhii*t tai just cvn- -:;*ra::-.in should L-.* fe-i.iw Ju auiliun particle* per cubic foot of air. the ::;ax::u:;:n fibre count of air. .>r iu uticrms in length! permitted. is I million fibre* per c-ubic :*xu - Many worker* remain at Wittenoom for leas than one year and leas than 50 per cant, of the work force, at any one time, have been continuously employed for more than four year*. A very rough estimate of the percentage of workers, with over four years exposure and suffering from industrial chest disease is 12 p~r cent, *-animated by expressing the number of w* Titers. detailed beiow. as a percentage of the number `>t w< ;k-n rtunoi m 5'.*59 whom- uutiai ixurung cenarsw was issued prior to 1955). ,, ----- -- 0---------- -- ** uiw iu y**r x. * pneure. For example, is 1068 there were do new ceaaa of Silicosis m the <M0 ys*r group, 20 cum 10-20 year group and 20 om in the 20-30 year group. Expressed as a percentage of the total number of mine worker*, thi* gives an incidence of Silicosis of approximately 1 per oent.percentage incidences These are notvery accurate and are not really comparable, but they do illustrate the grave hazard which existed at Wittenoom compared with the general mining industry. Since 1968, there have been one underground and five mill workers at Wittenoom definitely diagnoeed ae suffering from Asbe*toeis. All were advieed to leave the industry but for various reasons have not done to. Five of the six were investigated in hospital. The average exposure to asbestos dust in these eases vu four years only. There are two other suspect cases and two suggesting they are affected with a combination of Silicosis and Asbestosis. Apart from these, four others were diagnoeed with Silicosis, three having had a previous history of eoal abroad. These oases suggest that there ia elso an increased risk of Silicosis underground at the mine. The average exposure in these cases is 11 years (excluding previous mining). In two of these eases there is probable superadded tuberculous infection. Some newly diagnoeed cases of Silicosis are not included beesuse of previous lengthy gold-mining history which' eould reasonably be held responsible. There have also been a few cases of workers developing pulmonary tuberculosis without Silicosis or Asbestosis, but their number does not suggest any particular hazard at Wittenoom, other that eaenciated with mining in general. Three workers with a mixed gold and asbestos history have developed aQicosia and aebeetoeis. Four workers with a similar mining history have developed pure silicosis. Of these seven workers, the average exposure to dost faieindfag all was 12 year* and excluding previous (which is not entirely justifiable} was 7 yean. Conclusion The percentages quoted above (t.*., 12 per oent. of asbestos workers suffering from industrial chest disease with over 4 yean exposure compared with 1 per cent, of gold miners with over 10 yean exposure) are crude and probably paint too black a picture of the conditions which existed. With a working population, it is almost impossible to work out accurate incidences. However, the very high labour turn over at Wittenoom is necessarily associated with a short average exposure per worker and many workers at risk were protected simply because their exposure time was too short. At least one of these short-term workers has been diagnoeed as suffering from Asbeetoeis, many yean after he left the industry. The problem is essentially one of ventilation conducted with a proper appreciation of the relative importance and medical significance of the aebeetoe fibre as distinct from the silica particle. Despite the many marked improvements which have been effected at the Mine and HOI, I am not satisfied that the risk of industrial cheat diitmurr has been eradicated or even brought to par with the risk of Silicosis in tbe gold-mining industry. The prevention of industrial cheet disease is a medico-engineering problem and requires close liaison between the Minee Department, who are responsible for ventilation and dust counts, and the medical officers who are responsible for tbe periodical clinical and cheet X-ray examinations. J. McNDLIY. M.B., Ch.B., B.A.O., Chest Physician. 48