Document 85jXa43eJQ6dMG568m4LQ6ey

FILE NAME: Railroads (RR) DATE: 1979 May 8 DOC#: RR060 DOCUMENT DESCRIPTION: Letter RE Cobra Composition Brake Shoes S t . Paul Minn. May 8 , 1979 F ile : 417.22 44*^^ " yi 7 /~ PLAINTIFF'S EXHIBIT RR-166 A7 . < Mr. H. M. L a r y : <r Your l e t t e r o f A p r il 12, 1979, with a t ta c h e d copy o f a l e t er ' 7C fro u Mr. D. H. Burns in reg ard to c o m p o s itio n brake shoes c o n ta in - ing asbestos : In v e s tig a tio n s have been conducted by variou s aanufacturers to pro v id e a s s u r a n c e t h a t c o m p o s itio n brake sh o es do not pose an e n v i r o n mental hazard to e i t h e r p erson n el h a n d lin g them or personnel in c lo s e p ro x im ity to the point where th ey are u t iliz e d during braking operation. S p e c i f i c a c t io n tak e n by one m a n u fa ctu re r o f Cobra com position brake shoes is as follo w s: Cobra Shoes' Environmental C h a r a c te r is t ic s : 1. A c e r t a i n amount o f a s b e s to s f i b e r i s in c lu d e d in the compo s i t i o n m aterial and backing stock o f each Cobra brake shoe. D u r in g th e m a n u fa c tu r in g p r o c e s s , th e a s b e sto s and o th e r m a te ria ls are molded in to a hard block o f fr ic tio n m aterial which is bonded to a s te e l backing p l a t e . At th is p o in t, the asbestos is e f f e c t iv e ly contained w ithin the fr ic tio n m a t e r i a l . As a f u r t h e r p r o t e c t i o n , the e n t ir e brake shoe i s dipped in a s e a l a n t which w i l l p r e v e n t any loose a sb e sto s p a r t ic le s becoming airborne during handling of the brake s h o e s . The s e a l a n t a l s o r e s t r i c t s r u s t i n g o f the b a ck in g p l a t e d u ring o u t s id e s to ra g e and p r o v id e s the d i s t i n c t i v e red" shoe co lo r. 2. V a r io u s groups and in d iv id u a ls have in q u ired about the amount o f asbestos fib e r relea se d by Cobra brake shoes during b r a k i n g a c t i o n . To be a b l e t o a n s w e r t h e s e q u e s t i o n s , an e l a b o r a t e s e r i e s o f dynamometer t e s t s . w o r e ran i n 1971 d u r i n g which a l l the wear dust from v a rio u s types o f braking cy cles was c o l l e c t e d and a n a ly z e d . The r e s u l t s o f these t e s t s showed t h a t alm ost a l l o f the a s b e sto s f i b e r i s decomposed during brake a p p lic a t io n s . Less than one percent of the o rig in a l a s b e s to s f i b e r in the shoe remains as f i b e r in the wear dust and le s s than one-tenth o f th at becomes airborne. Since each sto p wears on ly a very sm all amount o f m a te ria l from each s u o e , and s in c e each shoe c o n t a in s o n ly a very sm all p e rcen ta ge o f a s b e s t o s f i b e r , i t can be seen t h a t t h e amount o f a s b e s t o s f i b e r th at boonos airborne with each stop is not s ig n ific a n t . _ t1 ^- r Mr. U . l i . Lary P a g e Two Hay 9, 1979 3. D u r in g tho same p e rio d o f i n v e s t i g a t i o n covered in (2) ab o ve, p o s s ib le t o x i c i t y of gases lib e r a te d by Cobra brake shoes d u r i n g b r a k i n g was a l s o g i v e n a t t e n t i o n . S top and d ra g t e s t s were perform ed and samples o f fcases g iv e n o f f during b ra k in g were c o l l e c t e d by a t e c h n ic ia n from an independent t e s t i n g l a b o r a t o r y . The s a n p le s were s u b s e q u e n t l y an a ly re d and the resu lts reported. R e s u l t s showed th a t the Cobra brake shoes gave o f f ad e x tr e m e ly t O ) E t i ;i * t e r i a l s , and o n l y s m a l l a m o u n t s o f h y d r o c a r b o n g a s e s . I t was concluded th a t no amounts o f harm fu l gases s u f f i c i e n t to be i n j u r i o u s to h e a lt h were l i b e r a t e d . 4. The o r i g i n a l Cobra brake shoe c o m p o s itio n also contained l e a s . A l l s h o e s m an ufactured s i n c e November 1975 have u t i l i z e d a l e a d - f r e e c o m p o s i t io n . The p r im a r y r e a s o n f o r t h i s change was t o e l i m i n a t e le a d from our p l a n t en viro n m en t fo r the p r o t e c t i o n o f m a n u fa c tu r in g em p lo y ee s exposed to the raw m aterial. 5 . In e a r l y 1977, Wmbco, in coope r a t i o n w ith JO H N S-M an sville re s e a rch p e rso n n e l, conducted a s e r ie s o f a ir sample t e s t s in t h e Bostom Subway i n an e f f o r t t o c a p t u r e c h r y s o t i l e f i b e r d u r in g t r a i n o p e r a t i o n s . S a m p le s were taken between the c a r s near th e tr a c k l e v e l , in th e p a s s e n g e r and motorn a n ' s a r e a , and on th e p l a t f o r m s o v e r a 1 0 - h o u r p e r i o d o f h i g h e s t d e n s i t y o p e r a t i o n . No s i g n i f i c a n t f i b e r counts were seen on any o f t h e f i l t e r s . Yours t r u l y , R. E . T a y l o r cc: b c : M r . D. Y . Hon Mr. R. F . J o h n s o n Mr. T. C . k o t n o u r Mr. J . A. B ichsel Mr. D . E. Whitney DE*W: mj n