Document EqObZ2Rv9z5RgR2NRrQmdd43g

FILE NAME: Talc (TALC) DATE: 1952 Apr 1 DOC#: TALC406 DOCUMENT DESCRIPTION: Letter to CT Dept of Health from Dr. Vorwald prl Is 1932 to* X3ta o tessa mf f e l t r i s i Estesisi sp^rt^is& LaUl '_, . Stet ? ' . Hs^gfer X9 C 80djte^ . , l^ss* fe te 4ftafe.TsayfgrpsSlyj^Ifcsas'rlag^gl iIl tSe1tf fJfia&smiss3s>7@,-2XrBi%n11sSSjatate^s^?i a a tl; ri& pesisi. Uvvsar* ' SaeeroSy. w w fc. f r te zy t- ya* wsfe S t fe s tessa tis8sroi8bi& M s r ts a li^ D '2; csp'ls- te 'teslamaii S&iiSBFS^'e # rX 19 & fc i . * 3 . a ' A sso d a 'M to ? ,'f o^oS-olo m & f W *** ^tgow.mfaefet&og%w&i@ll, p.a^&iraP.es iAS-t%e0&tSemSfe te tS to a tte si ffe : .. . . .; / SSmreiSy yew AJTsIS M t e J f e r n Id M 1671 CRMC-HT-TALC-000200 !&** Alisa Lo Coleman , - 2 - ' p r il 1, 1952. These-comments, we.knatii serve o n ly 'to emphasize the existence of oblons obvious.discrepancies and in no Tray aids in th e ir remedy Tilth regard, to 'dusts, the problem of se ttin g a ms^mm . allowable lim it fo r asbestos is one to which considerable thought has been given by various investigators From experiments con* ' dusted a t The Saranac laboratory i t has been show, th at only asbestos fib e rs longer than about 20 microns are capable of causing psribronchio- .Ja r fib ro s is ty p ical of asbestcisis in guinea pigs, r a ts , and rabbits The corresponding value for in d u s tria l workers is s t i l l a question but i t i s probably not le s s than 20 microns The upper lim it'is sim ilarly / in d e fin ite , From animal observations, the actu al concentration of these long asbestos fib ers 'which must be considered hazardous i s quit low, . possibly even le ss than one (1) m illion p a rtic le s per cubic fo o t.o f . air Howevsr, in an atmospheric suspension of asbestos d u st, even a suspension arisin g from lezjgfiber asbestos, th@ number of fib e rs longer than 20 microns i s generally only a small p a r t of th e to ta l number. I t would be lo g ic a l to f ix a threshold lim it fo r asbestos dust on a slid in g scale which would b@ regulated by the proportion of long fib e rs in the dust Tie are probably not ju s tifie d in adopting such an arrangement a t present because the range in the length of Bibers hazardous to in d u stria l workers is not known, and because th e determination of the size frequency fo r each d u s t.sample would be a burdensome ta sk . Some c la rific a tio n o f th is problss, however , is essential, For th is reason we suggest th e following modification fo r consideration Tentative Standard fo r Asbestos T otS ^cbm t<,,^jcHiding fib ers longer than. IC^a = 5 mP Pr hubic foot ' Inceptions The concentration of long fib ers (> XOp.) sh a ll not 'ScSTT^) per cubic foot. . . In reference to s ilic a d u sts, proper terminology should b considered a t th is time A d istin c tio n should be made between c ry sta llin e free s il ic a and amorphous s il ic a forms Diatomaceous ssa^H '^a^^cl^icaly'^ 'epareS ^S S ^Iw uF ^rE ca fumes are becoming in d u stria lly prominent These s ilic a s maybe hazardous aid producs specific disease unlike classical silicosis . We note th a t the same l i a i t for ta lc and for soapstone (20 nup. per cubic foot) is used by most states SFSe, however, have a .threshold of $0 m illion p a rtic le s fo r soapstone. Sine soapstone is an. impur form of ta lc and since commercial v a rie tie s o f e ith e r ta le or soapstone may contain an appreciable amount of quartz, i t would appear th a t in threshold lim it fo r the two m aterials should not d iffe r ; io / ^ CRMC-HT-TALC-000201 S?* sit ** Clmm . # 3 , - Fvrtber;'ater tttaenA "tas mmmm sui faaw Mwg? * 1 Boat (tt&e&aee fe1slUea) 2 S lte ' f e (feste $% tem S&fe) 3 Mofeas. fefe (W w % fe SiOg) $0 ap j>r .et&e e@t $0 * ^ a .o wasF ffegto 2 and g gssw bo sdss gHX et &fe feg*902-sfestosat f2,t! wws-pm^b te tesantes mss !i@t@fe% te ys& f m> flmegfnlM!gtf>$gjtfsts g,@Ufenfser srpetstiifeflssmtetear^ a tis'?roimnhdl Mobf2foMttgt[29{f'b@? te to ^s Shis vimr A o n fe gestes ofttb twi m^bOEghm ita km t o ptmwm @i t o dla t o ' MMs . ' ' . M tofestam t. ff ta^ the m te f e ' tbs toh@ M M . t e iifelM ^h^phL'heog&@s atr&iyfe& j^ uscite hw@ ^M feiteg^ont f fet^ ferfe gsesssaa^f te 0 &fe Stessa f e t o poraafej to re te % a a rdisi fesafetj^g as a <aag?lBg' atofwj.^ f@f>f.raDtw , ' Ite* @sg$fe fe fefep^spsgmt&m ga rami5tei@ a f3@rte% Bffp% Islte sM s&e &wgp$j?w t&^w? te lite ld m m w sM fe g t e te heap i s tMs* is o jo t &a ^ F 'to t w esa tefe a spotte of %Mm m% vm mms&l ^gfg ' . . Wife Itofe s^sg^ng, ' . . Stesm ly AJTgJS Arttmr X l^D Sfegfe^ Tmmm. TomAlm. 2S&ara I^iwa&esy 1673 CRMC-HT-TALC-000202