Document qd58KRo7GOMjzdkxbnZoDxGDx

FILE NAME: ALCOA (ALC) DATE: 1944 July 20 DOC#: ALC069 DOCUMENT DESCRIPTION: Letter with Test Results Br Fruncs 0o Frarj Me&Icdl Director Aliminun Be search laboratories Alisalnun Company of America M m ifensington,. Pennsylvania Bear Dr. Fraryi fh&afes for call lag my attentioa to the article os . \j.y. Silicosis from the isahufacture of Silicos AXleygo 2 recall tbpst wtes, I read It X Questioned the fact that the author had not exe!uMi|p-r'tfe'' handling of quartz sand as a scare of silica expo sure However 3 the difference in Ineidenoe of disease in the two plants might havg Sees .1 significant although good housekeeping would probably extend to the handling of raw material as well as the control of atmospheric dust., , ' i ff - - `~ "* .. Our own experiment,with your material is as couplets as us can now make it, The animal epidemic forced the sacrifice of the lact guinea pig 4 months after intraperltoueal Injection, All members of the series "revealed evidence of active irritation of a silicotic type, -he cellular picture was that of active proliferation of mononuclear and giant phagocytes with hyaline necrosis. The pre mature termination of the test precluded the formation of fibrosis although the early stages cf reaction indicated that this vould probaeli have ensued. 'J-he conclusion that the silica fume is capable of eausing silicotic fibrosis Is further substantiated by the nature of thi material aa Indicated In the enclosed, analysis,, It consists Xargelyy^:. wttg'm u B silica and this w have repeatedly demonstrated Is capable of- 5produolng silicosis an Injection la fine state of suMlvlsion. basar, la your plant would therefore, b@ determined by the Qua&tlty.Kand sis of the particles suspended la the air, subject, of course,;<.*o.-4h@& basic factor of inhalablllty. t s latter pcssit^fcitjsysan probably ^e"'^ assumed a the basis of the experience reported by Torsten Bras*^i^3 If you think It saestial we eaa soaplat# the Msast proof by injecting a series of rabbits ass& oteezvli^ the .probable development of fibroels over tbs fall seriad cf r~~ y"~~ f- On your part it might be desirable to have sob slr-'-borii# samples collected yith either an ispinger or an electrostatla preai-- pitator to establish both the atmospheric concentration and the size frequency of the particles. Presusably there are plenty of. fines in the atmosphere as our petrographer reports masy 2 slcrons and under0 in the sample submitted. Much of the dust is slumped In. masses up to 0 microns in diameter and there are also isolated particle of a .-similar size. With best regards, Sincerely yours ? LUG? RH Leroy II. Gardner, K. D. Director Smz Senslsgtoa PeB&eylvasia a sample &t dust aaxcedi : " " ....... - -- ' " Silica ost fFOffl Head of fWaaa fPortlaa thre'agla S2S Mesh) Silica Fas - no erfstalling phase. Siieg 0 O0X te 0 o8 micrshsi. PSTHOggAPHIO IWSPSGgloa Slumps S0 micros and under Particles W microns and msAes3with nany 2 microns and under Appears to be a 'glass, indgs variable from 1.482 to 1.522 Opaque material 8 So 10$ Quarts Bia Less than 1 percent 2$ CHo particle less than) 5 tals-ross ) Carbonates frae Quartz SiC 1*5 to 2$ 8i Trace Amorphous Silica Balance CHEMICAL ANALYSIS f^stisated)'1 Quartz ' Asorplsoiai Free SlOg Combined SIQp SiQ Si |j@23 and M g O s Xga&t&su Loss 1.5* S0*4 2.5 2o 0.5 0 o9 0o2 2.4