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PLAINTIFF'S EXHIBIT AC-3/ June 23, 1943 Dr V E Bowes Director of Research Owens-Illinois Glass Company Toledo, Ohio HE: Experiments on "Hydrous Calcium. Silic~.tr - 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 r.iht best plan further experiments to determine whether they are likely to cause chronic disease of the luny.s* . Chgr.l cal. Petrographic and X-ray Diffraction Analysis Rave the foiloiln^ approximate composition for the two samplesi Rotoclone bust Quartz - particle size 6 to SOp; little under ICp.............\Zy> Calcite - altered perhaps by heat 3/.- Chrsctile - extremely fine 25 Hydrated Calcium Silicate 50 Glass? . ' ' ' 3.0 Diatonaceous Earth Sander Dust . Trace Quartz - particle size 6 to 120p 7.5^ Calcite - altered < 5*0 Fibrous Material - Go&rae, matted to-gether Chrysotile j' tood? Fibre' j ' Bydrated Calciun Silicate i ii . 25.0 20-40 25-35? * / r U . 'E. Bowes -2 June 29, 1943 Beth of these materials proved difficult to reduce' to a sizo suitable for Infection purposes without crushing which cur experience has demonstrated will destroy the biological activity of asbestos; one of the suspicious components However, this ua3 obviously ovor-cone and suspensions of 200 nesh particles were prepared for Injection. The resultant suspensions In physio logical salt solution were alkaline; the rotoclone saaple about pH 7.5 and the sander sample about 9. There values will be checked as scon a? our potentiometer which is temporarily out of order can be repaired# Ac was' anticipated, the injection of materials of this degree of alkalinity caused immediate difficulties, ^hree of five pigs injected into the peritoneal cavity with the rotoclone sample died of j'e--tonit-ls, 2 to 4 weeks later, and with the still more alkaline sander dust, four of the five died within 6 to 9 days. When the two materials were introduced directly into the lungs by a tube through the windpipe, the alkalinity of the sander dust was apparently too high to be well tolerated, 3 of the 5 animal died of acute pr.evm'onia during the 2 week injection period (3 dosec rer> administered during this tire). The slightly lower alkalinity of the rctcclcr.e carryle^arparcrtlv made it tolerable and there vers no accidental deaths. These acute 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 dust entering the lungs in unit time would presumably be too email to produce a chemical pneumonia from alkalinity alone. The results to date are at least temporarily assured tc result from, the highly artificial methods of testing; * ' The chronic effects in which we are chiefly interested will require noro time for development. We aro dealing with a mixture that contains free silica and asbestos as well as hydrated calcium silicate, fibre etc. Eoth asbestos and quartz are pulmonary irritants capable of causing progressive pulrcnary fibrosis. Al though our analysis revealed little quartz of a particle size capabl of causing lung damage (3u and under), we do not know whether ouch particles could be produced in the manufacture or uce of this pro duct. Furthermore,-11 is generally assumed that the accelerated solubility of quarts in an alkaline medium increases its toxicity. i i 4 Dr. U. S* Bowes -3- June 29, 1943 * This we have never been able to confirm by ex- * perl-cnt but it still nay be true and further observation of you proiuct's action should shed more light upon this question. Asbsstos fibres, on the other hand, seen to lose their capacity to irritate when subjected to alkaline treatment. We have Just killed two animals that received, 1 month ago, rotoclone and sander dusts respectively by tube Into the lungs. Grossly, there is plenty of tissue reaction but its nature cannot be determined until microscopic sections are avail able, ^hese may give some indication of the future trend of events but it will take at least another 5 months before one kno-is definitely whether silicosis, asbectocis or other chronic pulmonary disease are likely to develop. ' Before making further plans for assay of thie mater I want to see these microscopic sections which should becomo available, within a week. Ihere are still enough animals in the various groups alive so that we should be able to decide whether it is necessary to undertake a largo scale inhalation experiment Very truly yours. Leroy U. Gardner, U. D Director