Document 67BN6eXYRVx6YgvR16kBBLDg

V* encloee berevit^, for your Information, a photocopy of ft letter sent to irofeeeor J.J. elihuff xeoftrdln,; hit reference to our work In a paper preeeuted In boaton on the 11ct fay,1J73 at tho Aserlor.n Indue trial :t;xlcue Conference. Ve were not present ct the ncetli^ end ere therefore tftkln,: thle opportunity to exprcee our point of view. a.C.IJMkiOlfi, K.li. B.Cb. D.I.h. Chief radical Officer. s.HOU.r:; Ch-ef !U>olth lhyalclat. Copy of thle letter alto tent to The Pretldent of the Aatrleer Induetrial Hygiene Aiaoeiatlon. and tht Coalman of the Aatrlaan Conference of Covemaent A Induetrial Hyglenlatt. era TURNER 35V RNEWA.IL mb UNITED Industrial Products Ltd aa/tow 12.7.75. Professor Irving J.Selikoff, Mount Sinai School of Kddicine, Fifth Avenue and 110th Street, nv YORK HY 10029, O.S.A. > hear Professor Selikoff. Ve have recently received a transcript of a tape recording of your address to the Amorican Industrial hygiene Conference in Boston on 21st Hay,1975 which.was ent to us because of its references to our work. If the copy enclosed herewith is a true representation of that addross and the graph shown by you, we Bust tell you that we find your assumptions and conclusions to be extremely Bialeoding. The ease made at the end of your paper appears to rest on the fact that the data which formed the basis of our Hygiene Standard* was scanty. You then attempt to extract data from the Figures in HCL`s publication* in order to show a discrepancy between tho original data and these Figures. Ve are astonished at your having communicated the contents of a private correspondence to the meeting which you addressed without having obtained our agroecent. Ve are also very iispleaced at the manner in which you have used the information we provided in order to launch '.'hit seems to us to bo a political i>_i.paiL:n in the 0SA eimod at discrediting our Hygiene Standard for asbestos. We cannot accept the implication that the liCL publication allows doubt to be cast on the validity of the BOHS Standard and axe of the opinion that such a conclusion is unwarranted. Comparisons such as those you have Bade between the Knox data and the HCL data are invalid for the following reasons i- 1. lb* paper by HCL was not intended to Justify or verify the EOUS Standard, and no reference is mads in this paper to environmental dust measurements. The results presented in KCL's paper were preliminary results and in the discussion section it was clearly stated that 'from the information currently available only tentative opinions can be expressed Ve are *- surprised therefore that you have boon able to road far more into tho incomplete picture presented than the author was able to do or even intended to do. 2. The populations reported by Knox and HCL were not identical nor were 'the very largo majority' of asbestos workers 'common to both surveys', as you suggested. 'Office personnel' were not included. The population studied by HCL consisted of workers in the reco&iised asbestos areas, together with maintenance, quality control and research staff. ). Knox reported on 290 men (not 913 as stated by you) with at least 10 years exposure since 1st January,1933< when the Asbestos Industry Regulations 1931 took effect, and who were still in the Company's employ on the 30th June,1966. HCL on the other hand has analysed the X-rays of a much larger population (1,267) . as of Kovomber,1970 irrespective of date of first employments some were in fact first employed before .. lat January,1933* 4. box sub-divided his population according to actual cumulative exposure whereas HCL*a was sub-divided by decodes olapsod since first exposure, irrespective of the actual number of years exposed. In view of these basic differences and othors which we will point out in due course, we fail to see how you derived the relationship between cumulative exposure and percentage of individuals affected on the graph which you showed (copy attached). The heading on the graph is obviously miBleeding as HCL at no stage in his report equated the radiological changes with 'asbestoois'. 5. Because it wee possible to estimate dust exposures for the Knox population, the BOBS Sub-Committee were able to arrive at figures for cumulative exposure expressed in fiLro yearo/ce. Co such exercise was ever attempted by HCL. This ie a further invalidation of the graph since you have attemptod to relats radiological featuros described by HCL to what ve can only regard as speculativs sxposurs data. 4. Knox only recorded X-ray ohangoa as bolng present which are possibly asbestotic, after taking the whole elinical picture into consideration, 'Radiological changes considered significant included those of increased general opacity of the lower lobes, blurring of the cardiac outline, pleural thickening and adheuions'.* /cont -J- 6* Cent/,,.,. SCI on the other hand attempted to analyse hie radiological fittings according to the UXCC/1L0 clasuification, an entirely different aet of criteria! and took no account of the elinlcal picture aa a whole. 7* The BOOS cub-connlttec decided t^at basal rales were tho 'key symptom* since all the s>cn with X-rny changes, by the Knox criteria! had banal rales, but sons with basal ralea had no X-ray changes.! HCL points out in his paper that he has not yet attempted to correlate physical signs and X-rny changes. 8. Ve are obliged to point out that the use of the words 'pulmenaiy fibrosis' by HCL in his paper may have aisled you, as they were uced to describe small opacities which prior to the advent of the UXCC/ILO classification nay havo been regarded as . oonuLstont with fibrotic changes. The use of this tens doos not allow for sub-division into profusion and typo of opacity as is now possible with tho UICC/ILO classification. For simplicity in presentation, HCL grouped all caeca showing evidence of these changes together, Irrespective of severity. Knox only included X-ray changes consistent with the clinical diagnosia of asbeatoalt. It is not possible to say, from the data that HCL has eoapiled, bow monjr parsons would fulfil the criteria for a clinical diagnosis of asbestosia, and to attempt to lllustrato these two very different seta of data on the same graph is simply not permissible. The clinical significance of the radiological changes observed cannot as yet be defluod. You appear to have ignored oooplotely the fact that the number of cases of aebsttoais in 1968 among 339 employees (men and women) exposed for 10 years er more aineo 193) in Bochdale and still employed, was 1,12? (i.s. 4 cases)3 as compared with Kerewether's finding of 44*4# (l.e. 39 oases) among 133 workers axpoMid lo years or more in the same industry in 1929** This lower incidence has occurred in spite of the fact that the Pneumoconiosis Medical Panels are better equipped to diagnose asbee tonis than Merewether was. In addition, during the years Immediately following 1939, there still was substantially groater exposure in certain jobs than in mors rocent times. /eont -4- 6. Coat......... In view of your consents and -our previous correopondencs ws should like to remind you that wo are in the prooesn of reviewing and bringing up to date oil the available data, and hope to present it for publication in the near future. Dr.Hoises' renarkc at Lyon woro never intended to suggest that the BOlIS Standard was not stringent enough. Tbs BOOS Standard is 100 fibre years/cc and therefore application of a 2 f/cc licit for periodo of less than 50 years han the effect of providing an aaple safety Bargin, The BOKS 5ub-conr:,i ttce, of which ve are both centers, recently reviewed the .Hygiene Standards for Chxycotile Aebestor^ in the light of the latest available data and recoursended that no change be cade at the present time. We are forwarding a copy of thin letter to the President of the American Industrial Hygiene Association, the Clmirrcan of tbs AOCIH, the Biroetor of NI05U and also the Asbestos Information Association of Korth America in view of their obvious interest in this important subject. Tours sincerely. H.C.LEVIWSOEN, H.B. B.Cb. D.I.H Chief Medical Officer. 8. HOUTS, Chief Health Physicist. Qcl