Document J3YxmNVoK3mDz21D8vokmJ77e

Febr uar y 4, 1964 H. C. Hal st ed, M. D. Amer i can Cyanami d Company Ber dan Avenue Wayne, New J er s ey Dear Doct or Hal s t ed I has t en t o r epl y t o your l et t er of J anuar y 31, and t o gi ve you my vi ew of t he pr oper use of anal yt i cal f aci l i t i es i n connect i on wi t h t he s uper vi s i on of wor kmen i n t he l ead- us i ng i ndust r i es. SJ The pr i mar y medi cal pr obl em i s t hat of obt ai ni ng t he anal yt i cal i nf or mat i on wi t h s uf f i ci ent f r equency t o pr event t he occur r ence of cas es of l ead poi s oni ng wi t hi n gr oups of empl oyees whos e expos ur e t o l ead may be danger ous . ( Ther e ar e, I know, ot her pr obl ems, such as t he neces s i t y, at t i mes, of obt ai ni ng pr oof of f act s . about whi ch t her e may be cont r over s y. ) The f r equency, t her ef or e, depends upon t he or der of t he magni t ude and t he degr ee of var i abi l i t y of t he occupat i onal expos ur e t o whi ch i ndi el duai s and gr oups ar e subj ect ed. Some occupat i ons ar e f ai r l y uni f or m and es s ent i al l y saf e; ot her s ar e mos t l y saf e, but wi t h a f ew t r oubl es ome and pot ent i al l y danger ous j obs; st i l l ot her s ar e s uf f i ci ent l y danger ous t o r equi r e f r equent checki ng. Car ef ul exami nat i on of t he" f i ndi ngs as s oci at ed wi t h al l of t he occupat i ons - and bet t er st i l l , al l of t hose obt ai ned f r pm al l of t he per s ons who have been s ubj ect ed t o expos ur e - wi l l demons t r at e not onl y t he pr es ent st at us of t he per sonnel , but wi l l s how t he t r ends of t he r esul t s, as wel l as t he degr ee of t he var i abi l i t y t hat may be expect ed under t he condi t i ons t hat exi s t . I t may be t hat none of t he r esul t s have r eached or appr oached t he cr uci al l evel of concent r at i on i n t he bl ood over some per i od of t i me. I f t hi s i s t he case, t her e i s l i t t l e pr obabi l i t y t hat t hey wi l l do so i n t he f ut ur e unl es s t he condi t i ons change. Of i t may be t hat a f ew i ndi vi dual s have l i t t l e or no mar gi n of safet y. Ther e i s no r ul e t hat i s r i ght i n i t sel f , but t her e s houl d be t he j udgment of a phys i ci an who mus t know t he degr ee of r i sk t o whi ch i ndi vi dual s and gr oups ar e s ubj ect ed. I make a pr act i ce of r emovi hg t he i ndi vi dual man f r om hi s empl oyment when t he concent r at i on of l ead i n hi s bl ood, as det er mi ned by our met hods of s ampl i ng and anal ysi s, r eaches 0. 08 mg. per 100 gr ams of whol e bl ood. ( Avai l abl e met hods i n use i n var i ous hands may yi el d hi gh or l ow r esul t s, as compar ed t o our s, and I have r eas on t o r egar d t hi s as a ver y cr i t i cal f i gur e. The er r or of anal ys i s I n our hands i s gener al l y of t he or der of -fr 0. 01 mg. per 100 gr ams. I f t he er r or i s -H0. 02 or even mor e, i n some i nst ances, t he poi nt at whi ch t he t r ans f er i s made mus t be l ower t han 0. 08 mg. per 1 0 gr ams. ) Such a m^n i s not i l l ( or ver y r ar el y i l l i n any way, i f he i s s een at t he t i me he r eaches t hi s l evel ) , but he may become i l l at any t i me, and s o7t o avoi d t he occur r ence of i l l ness. , t her e mus t be onl y a shor t per i od of t i me bet ween hi s r eachi ng t hi s l evel and t he di s cover y of t he f act . I n wor k whi ch can i nduce s uch a degr ee of abs or pt i on of l ead, one mus t r epeat t he anal ys i s f r equent l y enough t o t er mi nat e t he expos ur e pr ompt l y. Your own dat a s houl d s how you what i s Hal st ed, M. D. - ( 2) - Febr uar y 4, 1964 r equi r ed t o meet t hi s r equi r ement . I t i s not neces s ar y, as a r ul e, t o appl y t he same r ul e t o al l of t he empl oyees. Rat her i t i s good pr act i ce t o appl y t he t echni que of cont r ol t o t hose mos t i n need of i t , bear i ng i n mi nd t hat t he- r es pons i bl e phys i ci an wi l l i nsi st on knowi ng t he s af et y or pot ent i al danger of ever y occupat i on i n t he pl ant ( i f t hi s i s at al l f eas i bl e) and of deal i ng wi t h i t accor di ng t o i t s desser t s. Si ncer el y yotft-s, RAK: vr Rober t A. Kehoe, M. D. P. S. Af t er r eadi ng t hi s l et t er , I have some doubt t hat I have been as i nf or mat i ve as I s houl d be. I t s eems wi se, t her ef or e, t o add a wor d or t wo. I n gener al men engaged i n l ead- bur ni ng under r eas onabl y s at i s f act or y condi t i ons ar e not s ubj ect ed t o s ever e expos ur e t o l ead. Mor eover , t hei r wor k i s of t en i nt er mi t t ent . Thes e f act or s combi ned t end t o mai nt ai n t he hazar d wi t hi n modes t l i mi t s. When, however , t her e i s a per i od of heavy demand dai l y f or t hei r wor k, t he cur r ent l evel of expos ur e i s i ncr eas ed and at t hi s poi nt , cas es of l ead poi s oni ng may occur . Wi t h due al l owance f or your knowl edge of t he f act s i n t hi s s peci f i c si t uat i on, as wel l as your exer ci s e of j udgment , I woul d doubt t he neces s i t y of checki ng t hese men mor e of t en t han ever y si x mont hs . I f however t hey s houl d be s ubj ect ed t o an i ncr eas e i n t he dur at i on or s ever i t y of exposur e, you s houl d be pr epar ed t o check mor e f r equent l y. Agai n, however , I mus t i ns i s t t hat t he anal yt i cal t ool s houl d be us ed as ci r cums t ances r equi r e, r at her t han as a r out i ne. I t i s t he one t ool t hat t he phys i ci an can al ways cal l upon t o gui de hi m. RAK