Document 15O9R6LVXevB2aRXQBxd8egzm

D. R. JOHNS. M. D. R. J. L.IEHR, M. D. SUITES 204-5-6 FIRST NATi'L BANK BLDG. EAST CHICAGO. ^NDIANA September 19th, 1935. PHONES: OFFICE 220 RES. 1030 RES. 3116 Dr. Robert Kehoe, Kettering Laboratories, University of Cincinnati, Cincinnati, Ohio. Deajr Dr. Kehoe:- I have come in contact with a condition whe^e lead chloride was thrown off during a certain nrobess of manufacture. Knowing that it is more soluble and voltile than most other forms of lead, I wonder whether i t s ;toxicity is also more hazardous. I would be pleased to have your opinion in regards to its hazards, as to whether it might resemble somewhat the hazards of lead tetraethyl. I wish to thank you at this time for the reprints which you were so kind as to send me, and the next time I get to Cincinnati, I will take the liberty of 9oming out to see you. With best wishes, I am DRJ:E0 Very truly yours, . f> David R. Johns. ii.D X. \ 1935September 21# Dr, David H, Johns 20l|. First National Bank Bldg. East Chicago# Indiana Dear Dr. Johns s The type of exposure to lead mentioned in your letter does not seem to me off hand to be appreciably different in significance from that asso ciated with other Inorganic lead dusts. It is true that lead chloride is more soluble than some of the other lead compounds seen in the dusty lead trades# but In general I do not believe there Is very much difference In the toxicity of Inorganic lead compounds which are Inhaled into the lungs. Lead chloride Is not volatile at all except at very high temperatures, so that if in the process Involved, the lead chloride is thrown off In the form of a dust at ordinary tempera tures, there should be no question of volatility entering into the hazard. From what you have said I can not tell whether you are dealing with a situation in which high temperatures occur. If you are, the exact temperatures become an Important factor In a decision. The size of the particles will also be a question of some consequence. In general, the smaller the particle up to a certain point, the greater is the danger of rapid lead absorption. If the particles are sufficiently large, they will also settle out of the air rapidly and so will produce less con tamination In the atmosphere breathed. In the case of the inorganic lead compounds, It seems to be fairly well established both experimentally and in practice, that if the lead content of the atmosphere does not exceed 9 mgs* of lead per 10 cubic meters of air, the danger of poisoning is not very great. This, I believe, Is a question not of the nature of the lead compound, but of the quantity. As to the similarity of lead chloride to lead tetraethyl, you need have no anxiety. The physical and chemical properties of the two are so different that It is not to be expected that the mode of absorption or the manner of initial distribution of lead chloride would resemble that of lead tetraethyl. 2 Dr* David R* Johns I trust this answers your question, hut if; you wish to give me any further details, I should be glad to amplify what I have said, ' Very truly yours. RAKtla Robert A* Kehoe, M.D,