Document 5bRg1aeBvbm3Eexm7xaL9KoMV

December 19, 1938 Mr. C. Hosier Hr. R. Cryor hv. i nio~J i r* Du0ij;v^s^7^ -4 ,- . _ . . D'D NOT COME FROM PPG FiLES Attached hereto please find the report and correspondence which yon recently landed ne referring to the asbestos dust experiment beiiur conducted by Dr-. Gardner at aman c Inits. In the present report I find most of the information ia farther ir confIrma cion of previous results as reported in April of this year. ..hen this experimental -ori*. started in '*orch of 1D37,. Dr. Gardner outlined the objectives as bein? two-fold: 1* To observe b" x-ray examination any tendency tomortis development of fibrosis in the luam of experimental animals subjectod to high concentrations of asbestos dust over prolonged time intervals. 2. To determine if possible mother the irritation that develops Iron asbos-ce Gust in the lunr tissues is a result of chemical affects, or mechanical action. To date the results seen to point definitely to mechanical action as being the cause of fibrosis. This means 3imply that the ahepe and size of the particles that accumulate in the lun/rs appears to be of more importance as a source of irritation than the chemical composition of the partiolos. Dr* Gardner has found! contrary to what, was expected, that the finer particles cause less irritation than the coarser particles. Animals exposed to high concentrations of very fine dust for twenty months have not developed' fibrosis of Inn# tissues, whereas in previous experiments with coarser partioles of asbestos ddat, fibrosis developed in 15 months exposure. This appears to be an important point and sonsthir* heretofore not known. - ~* mmst of the aroerinental results seam to indicate that asbestos dust is probably less lively to produce fibrosis of the lungs than other forma of silica or ailioate dust. There is soma evidence to show that crysotlle fiber may be more harmful than other varieties of asbeBtoa that have been tested Including Anosite. mhls la not conclusive at this time however. ' io further ohec:: the mechanical theory os the source of irritation injections of coarse dust are being made this document was not a record of PPG INDUSTRIES, INC. D!D ` icJjflCVlED irs FILE'S AND CANNOT BE AU rHENTICAlED rrin-. -r--------INC. "f BB~0023897J 577 THIS. DOCUMENT WAS NOT A RECORD OF <rt I5M8-mc Dl N0T cTM oM December 19, 1933 Hr* C* Hosier Hr. H. 3. error NOTE: THK.DOCi;:;-:^-'o Attached hereto NOT COME FROM please fled the report PPG sad Hu t-% Os correspondede which you recently handed me referring to the asbestos dost experiment being conducted by Dr-* Gardner at Saranac Lake* In the present report I find moat of the information is further in confirmation of previous results as reported in April of this year* Then this experimental work started in JRar h of. 1937,. Dr* Gardner outlined the objectives as being two-fold: 1* To observe by x-ray examination any tendency towards . development if fibrosis in ths lunrs of experimental animals subjected to high concentrations of asbestos dust over prolonged time intervals* 2* 'To determine if possible whether the irritation that develops from asbestos dust in the lung tissues la a result of cnemical affects, or meohanical action* To date ths results seem to point definitely to mechanical action as being the cause of fibrosis*. This means simply that the shape and size of the particles that accumulate in the lungs appears to he of more Importance as a souroe of irritation than the chemical composition of the partlolea* Dr* Gardner has found, contrary to what, was expected, that the finer particles 'cause leso Irritation than the coarser partloles*. Animals exposed to high concentrations of Tery fins dust for twenty months have sot developed fibrosis of long tissues, whereas in previous experiments with coarser particles . of asbestos ddst, fibrosis developed in 1 months exposure* Th^s appears to be an Important point and something heretofore not known* Most of the experimental results' seem to indicate that aabeetoe dust is probably less likely to produce fibrosis of the lungs than other forma of silica or silicate dust There is sods evldenoe to show that orysotlle flt?er may be more harmful than other varieties of asbestos that have been tested including Amositc* This is not conclusive t til. m. hovmr* fiii"o023 898*7 to further ohetic the mechanical theory source of irritation injections of coarse dust are being made ; + ' * i` ' - J. * V-* i / t* I \ Pag* 3 * NOTE: THIS D0CW'~-;T c!0` COME FROM- PPG. Fii.ES into both 1uiu*b of each of a group of animals, tfith these animals ana luar ana bean artificially collapsed, and tana rendered isos lie* Tha other lung functions normally. if the mechanical theory la correct,""presumably, flbroala will occur In th* lung that moves and sill not develop in the collapsed lung*.-" Farther experiments ere non under nay to -gat additional information on the effects of esbestos dust In different particle sizes and possibly this may lead to son definite conolusiora es to vhare tha limits of tha hazard. In respect to particle size begin and and* l?y personal opinion is that if this uorfc is continued it "ill likely establish a background of information that rill be of oonaldarable assistanoa in designing ecruipnent and protective devices for eliminating the- industrial hazard. If it can be established that only a certain range of particle size and only definite concentrations of dust are harmful, our problem uill have been simplified to e considerable extent. H* S* errors 33 WENT WAS NOT A |^Rr0m SDUSTR1ES. J* j BB*0023899_J[ 57r