Document jgxb70BJXL5p881akV10xGRLp

t Mr. V incent Beckman F i r s t N atio n al Bank B u ild in g C in c in n a ti* Ohio D ear Mr* Beckmans- A few days ago you r a is e d a question as to whether or not the in h a la tio n o f lead compounds and p a r tic u la r ly le a d oxide r e s u lte d in i r r i t a t i o n of th e lu n g s and e v e n tu a lly f i b r o s i s o f the lungs w ith d is a b ility . C ircu m stan ces may a r i s e , in m ining and in .'grinding o re s , in which a s ig n i f ic a n t degree of exposure to s i l i c a is en co u n tered and u nder the:;e con d i t i o n s s i l i c o s i s may d e v e lo p . E xposure to le a d s u lp h id e (g a le n a ) and to th e o x id e s o f l e a d , on th e o th e r h a n d , may r e s u l t in some d e p o s itio n o f m in e ra l m a te r ia ls in th e lung t i s s u e , and w i l l c e r t a i n l y r e s u l t i r some a b s o rp tio n o f le a d , but i t does not cause pulmonary i r r i t a t i o n to any n o tic e a b le d e g re e , nor does i t cause pulmonary f ib r o s is . I t is true th a t the in h alatio n -f m inerals in general r e s u lts in d e p o sits of th e se m in erals la the pulmonary e p ith e liu m , in th e pulmonary ly m p h a tic s and in th e r e g io n a l lymph g la n d s . L ikew ise carbon from s o o t-la d e n a i r b lack en s the lu n g s . There I s , how ever, l i t t l e or no damage to th e lu n g s, and p r a c tic a lly no d is a b lin g f ib r o s is o f the lungs as a response to dust in the a ir except in the case of s i l i c a and c e r ta in s i l ic a te s such a s a sb e sto s. Gardner a t S aranac, and Sayers and h is a s s o c ia te s of the D .S , P u b lic H ealth S e rv ic e , have ex p erim en ted e x t e n s iv e ly w ith d u s ts o f v a r io u s com p o s itio n and s i z e o f p a r t i c l e . The g e n e r a l c o n c lu sio n s a r r iv e d a t by anim al e x p e rim e n ta tio n and e x te n s iv e human stu d ie s are th a t th e only p a r tic u la te d u sts which can be convicted o f prpduclng d is a b lin g pulmonary f ib r o s is a r e s i l i c a and a s b e s to s . Even carborundum , hard and sharp as i t i s , causes no im portant in ju ry and r e s u lts In no d is a b ili ty . I t is apparent, th e re fo re , th a t the In ju ry is not m echanical in type b u t is ra th e r thb s p e c ific chemical e f f e c t of s il ic a which not only causes a s p e c if ic type of 'f i b r o s i s , id e n tif ia b le by xray photography, but a ls o causes an Increased su sc e p ti b i l i t y to t u b e r c u l o s i s . No o th e r d u 3 t I s known to do t h i s , and lead oxide, by re a so n of th e wide exp erien ce which has been had w ith i t i s known n o t to produce such r e s u l t s . 2 I tr u s t th is w ill serve to answer your q u e stio n , I f any o th e r p o in t is a t is s u e , please l e t me know . Very tr u ly y o u rs, HAH. : i s iio h ert A. Kehoe,