Document DGVdoxkLXMdrGX7X1rjpyq6a4

October 9, 1967 Mr. Benjamin Levadie Vice Chairman, AST&M D 22 P.O. Box 607 Barre, Vermont 05641 Dear Mr. Levadie: I do not believe that there is satisfactory evidence on which to set a TLV for lead chromate. There is some evidence from industrial experience to indicate that the level which is now regarded as acceptable for American usage is inapplicable to lead chromate. However, so far as I am aware, no quantitative relationship has been established. Perhaps, if I were to see the draft proposal of Lead Industries, I might find a quality of evidence that would change my opinion. However, I tend to oppose the establishment of standards of any type that cannot be substantiated by satisfactory evidence. I see no reason for being impressed by the relevance of solubility in water as a basis for anything but an inference. There i3 no doubt that the respiratory exposure of workmen to the chrome colors results in the absorption of lead. The rate of such absorption, in relation to that which may be observed following respiratory exposure to the oxides, or the carbonate, or any other compound of lead, even under the conditions of variable size of dispersed particle, so far as I know, has not been established. I believe we had better go slow (simply for the sake of some reasonable degree of precision) in setting up further standards for lead, until we have sorted out the significance of the variables with greater precision than can now be attained. . Cordially yours, RAK: wp Robert A. Kehoe, M.D. Professor Emeritus of Occupational Medicine N13929 K A\JA0^lO 1kOO t