Document jpvyX3ymrap6ywzx6V14eg2R

V* i* m/.i . m . ;m mi: ioui-uation oi I'JMIII.III 1.100 rif"Tl*< AVl.Nl1' ii k.:,. *, f n *1I1UIV.I i*.. Pa August J, iV53V" UfcMOKANDUhi ON UESEAKCH PUCJ^CTS rOi\ . JOHNo-MAH VILLZ- COUPORATION fclructuro and Dual Characteristic o of Hy-Sorb A Atudy of tho structure and dust charoclorlstlcs of Hy-borb would require (tire# slops (1) *-ray diffraction U> dotermlno U crysUilUae (roe Allies Ia present and, it so, tho air.ouat (2) ecraon analysts to give information oa tho amount of linos, and (5) field studies to dotcimlae tho amount of dust actially dlssamtaatod lolo tho air uodor actual working conditions. Tho first two Items aro sUr.plo routine proc*dureo nud require qo spoctaI consideration. To conduct tho Hold studies U would oe necessary to know companies which are using fly-borb aad ohlala their cooperation to permit campling during actual use of the material. It would, of course, to possible to simulate working condltloos but It lo helloved that actual In-plant tests would have greater weight, ( Laboratory tesla have boon used In which tho dlooo.i.(nation of dnst * Is msasurod alter the duet Is dropped through a certain dleiaaco, buch lasts provide valuable Information whoa studying sovoral compounds to order to . obtain comparative data, Tho results for aay one compound would ho of ni*i, * * . ,.. ................. A I cl*Ul V*!/ lit 1 I'l Vr.J.i * \i u Cl* pt.' fr ti.lt to COil"<IO *t W r m*M! *$ . pound, *iiac^ mil/ '.* rt*ii>.niricc in involved this Icot t. mcII I*? o.i.ltt>d. U holatlw loulcltv of Marine aod Fresh V ater Lin to r.p.cpouc hartl* Muco lho Information desired Is relative toxicity, the intratracheal insufflation tost la welt oul'.ed (or this purpose. It la proposod, therefore, to atud> six dusts; narr.ely, natural, calcined, and Ut:x-calclr.cd marine dlatomaceoua earth and (ho corresponding fresh water dlatomaccous earth. The rat would bo used as tho experimental animal and the dust administered In a stogie doso^ Sufficient ealmals would to used in each ^roup to permit oacri(tc at.l, 6 *ud 12 months with the remainder beln held for 16 months. Thug, comparative Information would bo obtained on relative ahort-tlrr.o effects as & well as lonj-tln.e ollcctr. Tho PelaHve ToxlcUr of Various Asbestos Fibers /jnId, since the objective is to ootala relative toorlclW data, tho latratrachoal insufflation tosts should givo meaningful loforn ctlon. The pro- 4 cedure In goneral would parallel that for the marine and fresh water dlntomscoooe earth previously outlined. The study could bo Urnllod to crocldolUo, cirysotllo and a;-.'.o*Ub and we would wish to work cloooly with you la selecting tho material (or the test, I  i . rr,ir M i* * J'QxlcUy olJ*^rv5tiva Uo* b - Inhalation ut PlMoa.dts it l* balloted Uit InConitAUotl obtained by tbo toll `Mcnch*v%l , <*' Untioa to to ot llto <ftatoftCtfouo nmlU previously outline*! vnuld ^Irt answer lo this question, Periodic intratracheal losufllatioa tesla would glvs * % additional Information, However, actual inhalation tost* would bo required for a more precise evaluation. Tho design of equipment for toot proceduro for exposing aalmala intermittently to massive concentrations of tbo dual can readily be accomplished, la order to have a baola for comparison It would bo t necessary to conduct chronic exposures, This, (a tore, would necessitate fixing a prc?por levol for the chronic exposures. If the latrolracbcai lnsuf- flatloa testa wore conducted first, these data would bo helpful In selecting ^ exposure levels, Uowovar, If such taeto are not conducted first, It Is possi ble that Information available on exposures (a Industry would prorldo the oec ary information. Threshold L.lrnlt for Klux-Cftlclned IMatomacooufl Earth. Products The throshold limits ot $ million parllclco por cubic toot for quarts was established from human oxporleocc through inhalation. So far, no one . hat ever established a toxicity limit for fibrosis-producing dust through aoimst experimentation, It Is, of couroo, poosiblo through animal experimentation to obtain comparative results which would bo helpful In Indicating thn possible magnl- I /'i I ' Is.ile of * l K; r (or (! I n <Iu.t j lo c'f.j.pari sou v/lth olll*"' *U ot. 1 . u ? pi r*M om In panic..l\r r-o leul should ha given very csraful cnutl<'*u v.lU,n> tr-fom ntit'i.pt* log to nav/'tr Dm * uofftloo l*y nnlmnl experimentation, \t HU* undouM-a-fly ' meaning?* 1 flnrl worthwhile Information could b obtained, a coref *.l rppj '-loM ot the limitations of such data should be understood. Ppsalblo Relationship of Asheeloflta and Cancer of tho Loan The rveulta published by certain Investigators indicating o high IncW denco of lung cancer (a persons suffering Irom asbcstoolo, apparently are at varlancejMth the experience of soma other obsorvera. Tboro are several possible explanation* (or the divergence ot theso observations, It is possible that variations in the typo of operation or the characteristics of the flbcr'n.ay ^ play a role, and confirmatory information Is needed regarding the diagnosis * of both the aobcstosla and the cencor of lung. Until the necessary data are obtained by mean* ot a scientific epidemiologic study, the difference of opinion trill continue to exist, and oo convincing evidence will be available to ollber side. It U proposed, therefore, that the study to be undertaken will Include: 1, A critical review of tho Utoraturo with detailed atody of caaee reported by V.orewcther and Houper, who claim a high incidence of lijQg cancer among workor# showing asbcstocla, Z, A detailed study of tho operations la which those workers were i lavolvcd with reference to the exact typo of fihor to which they wore exposed, duration of exposure, and Information relating to age, ecx and race. Roaulls WS * >*<; f HtAU M M II#* I ' A ' * f '! A #r o( IaC >ro^'M:c un lh:> <ejiuive In^lcity ol Chr y fcolU r.i *: (Q - t In.dll* oM l** corrt-l.ved wllh thi* portion ol ti.e #..jrrc), .H 3, bi-ll*tlcul eJud/ of buih Anucffloolft end r&rriudixn cnnnr Jo j<5lrrntlrto the uo wUtc.v Uiu Oie^uoila was made. $. A parallel etalUUcal Udy ot a u(tlcioally largo group ol unaffected worker* to *ervo A* a control. licioro uadortaslag o-cli ao extensive epidemiological ourroy, it wlU bo uocctcary to dotercniao whether the rcqulrod areas tor t&7coiig&tioa are Available, Wo would wi#h to know how meay plant* u-q might have accoa* lo, and toVbal oxloot the Information outlined above might bo accessible. It la Anticipated that a propor study of thle tort would roves! infor ifiotioo pertinent le the problem ot oabaatoala, .as welt a* coatrlbutlng npocltic <. knowledge regarding the poaoiblo conaoctloo botweeu pulmonary carclrem* *ad aabeatoai*. 4 I >1