Document 6B2YpKpeQejQ2nZ18qaO8ORNg

FILE NAME: Visible Dust (VDT) DATE: 1966 DOC#: VDT007 DOCUMENT DESCRIPTION: Unpublished Report-Asbestos Toxicology Union Carbide UNION CARBIDE CORPORATION 370 PA K AVENUE, NEW WlffK, fi. V. 10817 ASBESTOS TOXICOLOGY REPORT I t ha b a sa known fo r many y e a rs th a t some perso n s working in a sb e sto s production vera prorie to develop a d isa b lin g lung d is e a s e . In tinse, t h is c o n d itio n bacasse known a s a s b e s t o s is and was r e la te d to exposure to high c o n c e n tra tio n s o f a sb e sto s d u s t. With fu r th e r e x p e rie n c e , i t was found th a t men cou ld work with a s b e s to s w ithout development o f lung d is e a s e i f dust concentrations e rally accepted that a iwmeurecakwe pt below work a 4 a 0 - certa hour in le week vel for . a I t i s now gen 1i f etisie without d ev elop in g a s h e s t o s i s i f the a s b e s t o s d u st p e r t i c I c o a s t i s kept a t or below 5 m illio n p a r t ic le s per cubic fo o t o f a i r . This du st con centration o f 5 m illio n p a r t ic le s p ar cubic fo o t o f a i r i s the Threshold lim it Value no f o r a s b e s t o s , and c a s e s o f a a e a a t o s ia a ra known to have occurred when xposu ras h a bean m aintained a t or below th is le v e l, d e sp ite la r g e - sc a le (mm u t i l i z a t i o n approaching .m illio n tons per year in the U .S.A .). T h is c o n c e n tra tio n o f d u st i s g e n e r a lly n o t 'v i s i b l e i n the av erage work a r e * u n le ss a beam o f li g h t c au sin g . T yndall e f f e c t i s p r e se n t. U su ally the bef o d r u e s t i t c s o n p centr resen a c ti e s ii !s ; must he visib le fremi S-1G m illio n p & r iic ia s p er la average ligh tin g conditions. cubic foot an S e v e ra l y e a rs ag o , i t was rep o rted th a t th ere was In crease in the incidence o f cancerous tumors, e sp e c ia lly o f the lu ag , asso c ia te d with a a b e s t o s ia . R ecen tly th ere have been r e p o rts o f some can cer o c c u rrin g in in d iv id u a ls exposed to a s b e s t o s d u s t , but who have not developed c l i n i c a l a s b e s t o s i s . I t i s b e lie v e d fey most a u t h o r it ie s th a t fch.es c a s e s have beam a s s o c ia t e d w ith exp o su res s i g n i f i c a n t l y exceedin g the Threshold Lim it bam V alu e, A m ajor m anufacturer o f a sb e sto s p rod u cts who ala mines a s b e s to s h as n ot t* a b le to show an in c r e a s e in can ceroaa growths in se n working where d u st c o n c a i*tra fisse were m aintained a t the Threshold Lim it F alu e. i s C o n tro l o f a s b e s to s d u st exposure th e re fo re n e c e ssa ry . The co n tro l methods are the standard ones ap p licatile to a v a rie ty o f dusty o p e r a tio n s . They In clude c lo se d flow sysfcesus, wet p r o c e ss e s where p o s s ib le , and adequate exhaust v e n tila tio n where openings in the system are n e ce ssary . P e lle tiz in g i s acasetimea used to improve the handling c h arac te r i s t i c s o f oth erw ise du sty t a s t e r i a l s . Where s a t i s f a c t o r y containm ent to s ta y w ith in the T hreshold li m i t Value i s im p r a c tic a l o r ivspsssaib le, AXf i e le n t and r e lia b le re sp ir a to rs are a v a ila b le fo r the p rotection o f the employee. A program o f environm ental m on itorin g ia h ig h ly d e s ir a b le to determ ine th at T hreshold L im it V alues a re n ot bein g exceeded. In, paper m an ufacturin g, i t would be d e s ir a b l e to know the d u st c o n ce n tratio n s where the a s b e s t o s i s dmapad from b ags in to the pulp s l u r r y . C o n cen tration s should a l s o fa determ ined where d u stin g occu rs i a fin ish in g p ro d u c ts. While i n i t i a l d o st determ inai:i-orjs sh ould be made a t freq u en t in t e r v a ls , once the le v e l has been e s t a b lis h e d a s s a t i s f a c t o r y , the frequency rosy he extended to' occasion al c a sts to assure continuation o f a sa tisfa c to ry condition. UCC 023214 to Pre-eE^sloyaent and p e rio d ic p h y sic a l exam in ation s o f w orkers are d e s i r a b l e . These should ineLode c h est X -rays insure thee the worker has oe c h e st c o n d itio n p r io r to work w ith a sb e sto s aad to determine th at no lung changes a r e r e s u lt in g fro work with a s b e s t o s . I t is believed that the addifeiaa o f asb esto s at the proposed in sa le v e l s du rin g the m anufacture of paper p ro d u cts would fee harm less to the consumer fatal stin g would have to be w e ll e e o f any L e w is a c c e p ta b le to the consumer fo r t b s a s b e s to s c o n ce n tratio n to approach the T hresh old L im it Value. l a con clusion , while asb esto s dust in excess o f the Threshold inL im it Value i s p o t e n t ia l ly harm ful, a s a re many o th er d u sts encountered in d u stry , i t i s a s re a d ily co n tro lled a s other such d u sts and i t can be used sa fe ly w ith approprit. p recau tio n s. C arl U. D em eh l, M. G>D irector o f Toxicology K. 3. Lanes Li D. A ssistan t freecot of Toxicology UCC 02.3215