Document NEvG9V1aeywoZVKVBEo3Go89p

72- j S' o iiCJyto 15th Aucuat.1972 Dr.I.J.S.likofT, H.9. Mount Sinai School of Medloine. fifth Arenas and 100th Street. K1V YORK, K.Y.10029 Dear Dr.Sellkoff. Thank you for your latter dated tha 9th August.1972. Walter Spilther baa forwarded your querlaa to m (1) nor* people have coot Into the 10 years and more category between 1966 and 1970* (2) eooa of the original Knox population will hare left our employ between 1966-70. Or.Knox reported on a group of aen(to the B01Q Coomitt*^ who had worked at the faotoxy for 10 years or aore alnce 1st Jenuary.1939 and were still in our eaploy on 90th June1966. It must,therefore,be obvious to you that the populations are not comparable beesuse of difference in their selection. With regard to your etteopted interpretation of figures 2 aul 9 in ay paper, could 1 draw your attention to the first two paragraphs under 'Discussion* on page 76. Dr.Knox did not use the UICC classification as It had not been adopted in 1966. I etteopted to use It but without the benefit of standard films at that tine* Doth Dr.Knox and 1 have reported our own observations in the light of our personal observations. The inportent conclusion is that found in Table 2 of ny paper indicating that the /cont.. l . As . * t / incidence of asbestoels (diagnosed by Fneuaoooaioels hoards) in 1966 among 999 eaploytee exposed for 10 years or aore in Rochdale, was 1.12 (l.e. 4 eases) as coapared with Merowethsr'a finding of 262jf aaong 563 workers froo the textile industry in 1929* This result has been achieved by engineering oontrole and the duet levels achieved by these aethode have been used by Knox and the fiOIS Cosalt tee to explain the decrease in the incidence of asbestoels and to use these figures in the formulation of a standard which could be applied by industry. K other data upon which to baas a standard waa available and to the beat of mj knowledge is still not available. Tbs Department of Employment's survey of asbestos workers cay eventually help to resolve some of the outstanding questions with regard to asbeetoe exposure, radiological features of exposure end the development of respiratory eynptoms end signs. 1 hope this explanation helps to allay son# of your apprehension. With kind regards. Yours slnoerely. H.C.L&/IR30HH. H.B. B.Ch. D.l.H, Chief Medical Officer. Ct j&w & to VO to u> ..X". INTIFFS XHIBIT