Document 6w9obnzyyZ1973QOK6oVQEJ8g

I'mlVasor Irvine J StOiknff Mount :ilu.it School oT Miiltctix* Fifth Avenue and IJOtli filHMtl Now York NY 10029 \ USA to lo nent on TUA writing paper Dour I'rofoMscir Solikol'f, Wo hnvo rocontly rrrulvnd a transcript of n t:ipo roconlinr of your address to tbo American Industrial llygj ono Confornneo in Don ton on 21st Nay 1973 which wns won l to u.s huenuao of its references to our work. If the copy onclhmmi norewith is a trim represents tion of that nddresn and the graph shown by you. wo must toll you that wo find your assumptions and conclusions to be extremely misleading. Your enno appears to rost on tho fact that tho data which formod the bnnis of tho Hygiono Standard1 was scanty. You thon attempt 2 to. oxtract data from tho Figures in HCL's publication in order to show a discrepancy between tho original data and those Figures. Wo are disconcerted at your.having communicated the contonte of a privato correspondence to tho mooting which you nddrossod without having obtninod our agreement. We arc also very disploased at tho manner in which you havo unod the information we providod in order to luunch what seoms to us to bo a political campaign in t lie USA nimod at discrodi ting (thuonly>Slygione Standard in 3xistenco for asbestos. Wo cannot^TTecopt tho implication that -ho MCI- publication allows doubt to be cast on tho validity of he UOMS Standard and nro of tho opinion that such a conclusion h unwarranted. omparIsons such as those you have made between tho Knox data nd tlio HCL datn nro invalid for the following roaaonot A-. -2- r A, W 1. Tho paper by IICL wan not inlt'iidi'd to Justify t.r verify the UOHS Standard, and no reference in inado in this paper to environmental dvmt measurements. Tlio ronnltn p, entod in HCL'a paper woro preliminary rnnulta nnd in the diacu.s;. J on section it waa clearly staled that "from tho information currently aval l-LI iv. . >4 bo oxprosspd". We nro surjirisod thoroforo thnt you have boon able to rond far moro into tho incomplete) picturo prosonted than tho author.was nblo to do or oven intonUod to do* 2* Tho populations reported by Knox nnd 11CL woro not identical nor woro "tho very largo majority" of asbestos workors "common to both survoys", as you suggested. "Office personnel "woro not included. The population otudiod by 11CL consisted or workers in the rocognisad asbostos areas, together with maintenance, quality control and resoarch staff. 3. Knox roporJLod on 290 mon (not 913 ** stated by you) with at least 10 years oxposuro sinco 1st Jnnuary 1933, whan the Asbestos Industry Regulations 1931 took offoct, and who were still in the company's employ on 30th Juno 1966, HCL on the other hand has analysod tho X-rays of a much larger population (l,287) as of Novombor 1970 irrespective of date of first employmont{ some woro in fact first employed before let January 1933. J<. Knox eubdividod his population according to actual cumulative exposure whoroaa lICL's was subdivided by docados olapsed sinco first oxposuro. irrospectivo of tho actunl numbor - 3- of yours oxpoHcd. In vlt<w of llioni* ImnJc <li ITorcncvh oral othoru which wo will point out in duo cuurou, wo Tali to see how you riorivoil t)io rolationnhip botwoou n ilutivo exposure and pcTcontnj'o of individuals nffoctod on ttio graph which you showed (ropy attached). Tho heading on th graph it* obviously mi siadI nr as HCM. no tfn in hi roport oquatod tho radiological changes with "nsbestosis". Bocouho it was possible to estiinn''> 'bi-t exposures for th Knox population, tho HOHb Sub-Commi l wore nblo to arrive at figuros for cumulntivo oxponuro oxproNsod in fibro yoars/cc# No such oxorciso was evor attempted by HCL. This is a furtlior invalidation of tho graph sj.nco you have attempted to relato radiological features doscribod by HCL to what we can only regard as speculativo exposuro data. 6. -Knox only recorded X-ray changos an boing present which are possibly asbeatotie, after taking tho whole clinical picture into consideration. "Radiological changes considered * significant included thoso of incroasod gonoral opacity of the lower lobes, blurring of tho cardiac outline, pleural "t i thickening and adhosions"HCL cn the othor hand attempted to annlyso his radiological findings according t& the UICC/lLO classification and took no account of tho clinical picture aa * a wholo. 7# The UOHS sub-committoo decided that basal rales wI "key symptom" since "all tho men with X-rny changes^had basal rales, but somo with basal ralos hnd no X-ray changes"*^ HCL points out in his paper that ho has not yet attempted te correlate physical signs and X-rny changos. -k- 6* Wo tiro obligod to point out that th uko of the word* "pulmonary fibrosis" by HCL in hi* paper muy linvo misled you, no thoy woro usml to doocribo small opuri'is which prior to tho advent of thn UICC/lI.O classification may liiivf boon regarded on consistent with fibrotio chanson. Tho uno or thin tonn doos not allow Tor subdivision Into profusion nnd typo of opneity as is now por.ribJc w!th tho UICC/lLO clnssificntlon. For simplicity in presentation HCb grouped nil ensos showing evldonco of those changes together, `irrospoctivo of novority, Knox only includod X-ray changes consistent with tho clinical diagnosis of asbeato* is. It Is not possible to say, from tho data that HCL has compiled, how many parsons would fulfil tho , critorin for a clinical diagnosis of asbestosis, nnd to attompt to illustrate those two very different sots of data on tho some graph is simply not permissible. The olinieal significance of the radiological changes observed cannot as yot bo dofinod, You nppoar to hnvo ignorod complotoly tho fact that the ntimbor of cases of asbestosis in 19&8 among 335 omployoes (men and womon) exposed for 10 yoars or more since 1933 In Kochdulo and still omployod, wn 1.12)1 (i.e. 4 casespas comparod with Morowothor's finding of (i.o. 59 cases) among 133 workors exposod 10 yoars or moro in tho some industry in 1929P This lowor incldonoe has occurod in spite of tho fact that tho Pnoumoconloai* Medical Panels are bottor iKpIppod to dlngnoso nsbostosis than Morowother was. In view of your comments and our |>r< vlntix wo should liko to remind you that wo nru in Dip prnci'ii* of roviowing niui briiiciiif: up to (Into nil tho aval lab)' data, hikI hopo to proaent it for publication in tho nunr future, Ur llolmoa' remarks at Lyon worn not intondod to aueftoat tlmt tho HOIIS Standard was nut stringent enough, Tho HOUR P( r.ndsrti la 100 fihro yoara/cc and tlicrof'oro application of a 2 f/ne limit for porioda of Iona tlian 50 yearn sine. Id allow an ample safoty margin. Tho DOIIS Sub-Commi t too, of which wo aro both mambnrn: recently rnviowoii tho Hygiono Standards for Chrysotlle Ashestos^ In tho light of tho latent nvnllablo datu and rocommonded tlmt no chungo bo made at tho present tlmo, Vo aro forwarding a copy of this lottor to tho President of the American Industrial llygiono Association, tho Socre+.nry of tho ACG1H, and also tho Asbestos Information Association of North America in vlow of thoir'obvious intorast in this important subject. Yours sincerely, 1! C Lowinsolm, Chief Medical Offieer S llolinos, Chief Hoalth Physicist