Document Yn09rzyGyVa08gYN5Oq7aMr8

<J u Charleston, S.C. Hay 6, 192Q Hr. Julian Mitchell Charleston, 5. C. Dear Hr. Mitchell:-- X am. very glad Indeed to have the opportunity of exeminlq^^ Dr. Gardner's report on recent investigations of the effect of flna asbestos, dust as compared with longer fiber dust. As he says," if the hypothesis constructed on the basis of this ex-- periqtaatation proves tenable, our previous Idea that the finer the dust the more harmful will have to be revamped* It all. goes to show that -the oaly thing that can yet be positively stated is that in the human sufficient exposure to asbestos dust^will causa asbastosls,but what constitutes suf ficient exposure still remains subject to lack of complete knowledge* It might be .wall as a forward-looking program for the asbestos factory to begin to think more about precautionary measures in departments where the dust is coarser, although even apparently leas in amount* As Dr. Gardner says, there are things about astestosis which have not been satisfactorily explained as yet. One thal; remains with me and my local material is, why tha advanced old cases show so much evidence of pure silicosis. I have not been able to get. any evidence that any of the asbestos used here may have had free silima in it, but, unless asbestosis under some conditions shows the feature of 3ilicosis, it must have &ad. I think that thl3 question, that is whether local cases have not been exposed to free silica in addition to silicates, is very important for tha local industry to clear. I do not think that Dr. Gardnerra experiments have any practical bearing on whether there i3 such a thing ea esbastosis. Hr. Jeffords suggested to me that conclusion, out of tha extract from Dr* A. J. Ireland lathe South African Mining and 3ngiaeering Journal of Jan. 15, 1938. All I can conclude from this extract is that apparently under the conditions existing there, the exposure is insufficient. Whatever those conditions may be it might be well to ascertain, if possible. . neither do I follow fully tha suggestion in Hr Yandever Brown's letter of April 28, 1938, that Gardner's experiments would negative the claim that the fibrosis is of a progressive character. If tha material is long enduring the fibrosis night keep up even though the influance i3 only mechanical. I if;at stimulation from tha South African report to again, remind that no one can know what the hazard here is uatil the /j same sort of examination of workers is. done here. -4 I shall be glad to talk these matters over with you at 4 1 any convenient tins* Sincerely yours Kenneth LI. lynch KHL/f Kenneth M. Lynch, LT. D. OS3oo