Document 4bjQo0ZaaEZbKLqjOxM7G8OQ

F eb ruary 18, i 955 D r. W illiam M. A ldredge National Sine Comuauy, lac. B a r tle sv ille , Oklahoma D ear Doctor A ldredge: Y our le t t e r of N o v em b er 16 to m e h as gone u n a n sw ered fo r so lon g a s to have little or perhaps no u sefu ln ess to you, but I sh a ll fu lfill the purpose of co u rtesy , at le a s t, in rep lying at long la s t. The fa ct is that I've been so swam ped with things that dem anded m y im m ed iate attention ev er sin ce m y return from a n e c essa ry trip abroad as to have no tim e for m y .correspondence. . ' . . ... ' ' . .. . . ' . Y ' .. ' M eanw hile, I b eliev e that you w ill have answ ered your own questions :in s o f a r a s th e a p p a re n t e f f e c t iv e n e s s of the m a s k s w orn b y y o u r m e n a r e concerned. I cannot in terp ret the data in this relationship sin ce I do not have the detailed data oh the m en involved, but it appears from die resu lts that I have before m e that the actual absorption of lead by your m en has not been excessive. T here are a num ber of things that should be said about a ir a n alyses. G ranting that the sa m p les of a ir are actu ally r;:p resen tative of the environm ental conditions, i . e . that they are taken in proper p laces and in su fficien t num bers to m aintain th eir rep resen ta tiv e ch a ra cter, and granting that they a re an alysed and in terp reted p rop erly, they ser v e the v ery useful purpose of establishin g the extent of the potential hazard. The a c tu a l h a z a r d , h o w e v e r , i s not co n fin ed f a 'the -in h a la tio n o f le a d com pou nds , n or is the fa te of that which is in the a ir determ in ab le without obtaining v ery good inform ation on the size of the p a rticles, the extent of the-use of resp irators and other protective d ev ices, etc. You w ill note from your own data that what ia in the a ir need not be taken into the body, sin ce a p p aren tly th e r e sp ir a to r s exclu d e it. It is the com bination of th e se fa c to r s that tend to reduce the sign ifican ce of a ir an alyses as com pared to an alyses of the urine or blood or tissu e s o l the exposed person . H ow ever, w ise p e o p le in th e le a d tr a d e s u s e both m e th o d s. In p r a c t ic e one u s e s a ir an alyses for quick and convenient app raisal of the air-borne hazard, while he u s e s b io lo g ic a l a n a ly s e s to m e a su r e the h y g ien ic sig n ific a n c e of the.._ ! total actual hazard. The one is the tool of the en gin eer to keep h is sights clear, in relation to equipm ent and its efficien cy , w hile the other is the tool of the doctor to keep h im self in a sound p osition in relation to h is p ro fes sional resp on sib ilities. Sincerely yours, EAK e Robert A. Kehoe, M. D.