Document DDaaNrO2bGzqx3ag5MZm0xrXa

TETRAETHYL LEAD (TEL) . 0.075 mg/ m^(as lead ) - S k in Fxten sive and ca r e fu lly co n t r o lle d m an ufactur in g exp er ien ce has in d ica t e d t h a t a ' le v e l o f 0.075 mg-per cu b ic meter o f a ir (measured as lead ) is a good gu id e lin e fo r an allow ab le a ir con cen tr a tion o f TEL. Desp ite t h is gu id e lin e i t has been r ep eated ly noted ' t h a t the a b ilit y o f TEL to p e n e tr a te the skin makes r e lia n ce on the air b or n e con con tr a- t icn im p r a ctica l in many s it u a t io n s ( 1 ) . A con cen tr a tion o f 100 mg (as Pb)/ m3 fo r one hour may produce illn e s s ( 2 ) . One ten th m i l l i li t e r o f TEL a p p lie d to the back o f a r a t has caused death w it h in 24 hours ( 3 ) . . , The s ign s and symptoms o f poison in g from t e t r a e t h yl lead r e la t e p r im a r ily to the ce n t r a l nervous system and d iffe r from those due to in o r ga n ic lead p o is o n in g. The d eter m in ation o f lead in the blood is o f no valu e in e va lu a t in g the degree o f ab scr p - . tion o f TEL. Ur in ar y con ce n tr a tion o f lead may be used as a guide to ab sor p tion o f ' TEL ( 3 ) . Relian ce on in d u s t r ia l-e xp e r ie n ce is the b a sis fo r esta b lish m en t o f the th r esh old lim it but i t must be r ecogn ized t h a t in h a la t io n may be o f on ly minor importance in p r even tion o f undue exposur e. Percutaneous ab sor p tion may be a very s ig n ific a n t fa ct o r and must be consider ed a t a ll times in plann in g p r o t e ct io n . Refe r e n ce s : . . . 1. 2. " 3. 4. Ethyl Cor p or a t ion , Medical Department: per sonal communication. . Flem in g, A .J.: Lead Symposium Feb. 25-27, 1963, The Ke t t e r in g La b o r a t or y, Uni -- ve r s it y o f Cin cin n a t i. . ' ' ' Laug, E .P ., Ku n zel, F.M.: In d . Hyg. Tox. 30 , 256, (1948). . Sa n d e r s, L.W .: Lead Symposium Feb. 2 5 -2 7 , 1963, The Ke t t e r in g Labor ator y,- Un i ve r s it y o f Cin cin n a t i. . . \. . TETRAMETHYLLEAD (TML) - Skin 0i075 mg/ m (as lead ) - The 30-minute LCTM fo r mice is 4 0 .8 g/ m3 a t a one day follow -u p p er iod o f obser vation and 8 .5 g/ m3 a? a ten day follow -u p per iod ( 1 ) . The LCcg fo r r a t s is ap p r oxi m ately 8.87 m g/ iit e r ( 2 ) . The s t u d ie s o f Da vis , e t a l. ( 3 ) , though lim it e d to s ix dogs, should be con sider ed ca r e fu lly as they in d ica t e t h a t dogs are more s e n s it iv e to TML than ar e r a t s . There are no long.-term animal in h a la t io n s t u d ie s a v a ila b le . Comparison o f the p h ysica l-ch e m ica l p r o p e r tie s o f TML and the b e t t e r known TEL .in d ica t e s t h a t TML is con sid e r a b ly more v o la t ile ( 4 ) . Desp ite the d iffe r e n ce in vo la t i l i t y and m anufactur ing exp er ien ce which in d ica t e s t h a t atmospher ic exposure is about thr ee times h igh e r in the TML p la n t than i t is fo r TEL m an u factu r e, the con cen tr ation o f lead in the ur ine o f the workmen exposed to TML and those exposed to TEL were not s ig n ific a n t ly d iffe r e n t . Ne it h e r group had symptoms o f illn e s s and a ll u r in e -le a d con ce n t r a t ion s were w ith in normal lim it s ( 4 ) . - . Manufactur ing exp er ien ce has in d ica t e d no apparent problems .under the p r esen t s ys tem o f h ygie n ic co n t r o ls . Desp ite the d iffe r e n ce i n .v o la t ilit y between TML and TEL, the th r esh old lim it valu e o f 0.075 mg o f lead/m3 o f a ir appears to fu r n ish an ample margin o f s a fe t y for e it h e r compound. Skin ab sor p tion is a p o t e n t ia l a d d it io n a l hazar d with TML. . Refer en ces: 1. Ca s t e llin o , H. e t a l .: B r it . J . In d . Med. 2 0 , 63 (1963). ' 2 - Cromer, J.E .: B r it . J . In d . Med. 18, 277 (l9 '6 1 ); . - 3 .' . Da vis , R .K ., e t a l .: Ar ch . Env. Health" 472 (1963). . 4 . ' d e Tr e vi.lle , R ., e t a l . : Ar ch . Eng. Health 5^, 532 (1962).