Document 71K48vMG4EZGmK2RXvKK7odLB

! .1 14, 'if*'? Tj .3* Dr* O'. S* Bowes Director of Research Owens*Illinois Glass Company Toledo* Ohio RBs Experiments on "Hydrous Calcium Silicates" Dear Dr* Bowes* In reply to your letter of June 25, I can report that samples of both Rotoclone and Sander dusts have been In* jected into guinea pigs to determine whether they would be tolerated and how we might beet plan further experiments to determine whether they are likely to oause chronic disease of the lungs* Chemical. Petrographic and X*rar Diffraction Analysis gave the following approximate 'aexposition for the two samples& .Botoclona Dust Quarts * particle else 6 to 80w little under 10p............ 12% Caldte * altered perhaps by hast Chraotlla - extremely fine Hydratod Calcium Silicate Glass? Dlatomaceous 'Earth Sander Dust Trace Quarts * particle alsa 6 to 120(i Calclta-* altered Fibrous Material -- Coarse, matted to-gether Chryaotile Wood? Fibre Hydrated Calcium Silicate 00031: Asbestos Litig Saranac Lake 1989 Depos. iExhibit p.24 r|LAINTIH=!Ss ^ EXHIBIT .** O I r. 9 7. . Bowes Jure 29, 1943 tetb of these materials proved difficult to reduce to a size suitable for injection purposes without crushing which cur experience has demonstrated will destroy the biological activity of asbestos; one of the auspicious cojppcrer.ts. However, this was obviously over-come and suspensions of 200 mesh particles were prepared for injection. The resultant, suspensions in phyalolo^lcal salt solution wore alkaline; the rotoclone sample about pH ".s n.nd t^e sander sample about 9. These values will be checked as 3con as our potentiometer which is temporarily out of order can be repaired. Aa was anticipated, the injection of materials of this degree of alkalinity caused immediate difficulties. 'Ahree of five pigs injected into the peritoneal cavity -ith the ro'volone sample died of peritonitis, 2 to 4 weeks later,and with the still more alkaline sander dust, four of the five died within S to 9 days. then the two materials were introduced directly Into the lungs by a tube through the windpipe, the alkalinity ~f the sander dust was apparently too high to he well tolerated, 3 of the 5 animals died of acute pneumonia during the week injection period (3 doses were administered during this time) The slightly lower alkalinity of the rotoclor.e sample apparently made it tolerable ar.d there were no accidental deaths. These aeut# reactions to relatively large quantities of,the "hydrous calcium silicate" are as indicated, probably due to*the pH. of the dust suspension and probably have little bearing upon the problem before us* By inhalation the quantity of fine duet entering the lungs in unit time would presumably be too small to produce a chemical'pneumonia from alkalinity alone. The results to date are at least temporarily assumed to result from the highly artificial methods of testing* The chronic effects in which we are chiefly interested will require more time for development* Be are dealing with a mixture that contains free silica and asbestos as wallas hydrated calcium silicate, fibre et^ Both asbestos and quartz are pulmonary irritants capable of oauslng progressive pulmonary flbrcsls* Al though our analysis revealed little quarts cf a particle size capable of causing lung damage (3a. and under;, we do not know whether such particles could be produced in the manufacture cr use of this pro duct* Furthermore, it is generally assumed that the accelerated solubility of quartz in an alkaline medium increases its toxicity. 000209 Asbestos Litig. Saranac Lake 1989 Depos. Exhibit p.26 -- f - . _>cwes June lb, 194b Shis we have never boen able to confirm oy exr :rl 'unt. but It still r.ay be true and further observation of jour product's action should shed more light upon this question* *.abv;rto3 fibro3, on the other hand, sees to lose their capacity : o irritate when subjected to alkaline treatment* T.q have just killed two animals that received, 1 th a.-jo, rotcclone and sander dusts respectively by tube into t' e lungs Orezsly, there is plenty of tissue reaction but its na-'-vru ounnet be determined until mlorosooplc sections are avail able. ^hese may give sore Indication of the future trend of events but it will take at least another 5 months before one knows definitely whether silicosis, asbestos is or cthor ciircnic :'"l_onary disease are likely to develop. Before making further plans for assay of this material I want to see these microscopic sections which should becoue available within a week. There are 31111 enou-jh animals In the various groups alive so that we-should be able to divide whether It Is necessary to undertake a lunge scale Inhalation experiment* Very truly yours. Leroy 'T* Gardner, *! D. Idrector 00031 i. Asbestos Litig. Saranac Lake 1989 Depos. Pvh '' V> -I -- n . P.