Document vVyRE3jZ32Dvk3Xmqy8q4bykb

August 24, 1951 Mr. H. A. Thiemann, Engineer Hartford Accident and Indemnity Company Hartford 15 Connecticut Dear Mr. Thiemanni In reply rc your questions concerning the practical hazards of the present use of lead aaphthenate and lead phthalate in the manufacture of oainbs, enamels and the like, I can give you no definite answers in terms uf experimental data or experience. I can, however., make a few comment a that may be pertinent to the general problem. First, vivh reference to the solubility t " those materials in the alimentary tract, vith the exception of a fev compounds which for all practical purposes are almost wholly insoluble in the various parts of the alimentary tract, this factor is of minor importance. There is no compound of lead that is readily absorbed in the alimentary tiact, whether soluble cr relatively insoluble. Even under the most favorable conditions hie introduction of load into the alimentary tract in lov to moderate dosage results in little absorption ;ei cent age vise (less than 10 per cent). Tills does not make ingestion of lead totally unimportant, but it dees make it of relatively small importance, as compared to inhalation. Therefore, ry .'dr.h of course, that ve simply cannot use the solubility of leed in the alimentary ^ra c t , as arrived at by indirect observations, as a basis for determining occupational hazard . As to akin absorption, I must take exception to your statement that lead acetate and lead oleate are readily absorbed through the s k i n . r;:his is simply untrue. Lead oleate is absorbed slowly and ineffectually, vhile lead acetate can scarcely be said to be so absorbed at all. 'tetraethyl lead, on the other hand, really is absorbed rapidly, as are also some other ?,,iquid alkyl compounds of lead, so far as they have been studied. Of the compounds now employed in industry, tetraethyl lead is the only one that poses a real problem in that regard. We have made a fev observations, recently, on lead octoate. It is absorbed so slovly as to be of negligible importance in this r e g a r d . We should be glad to examine the two compounds of which you speak if someone is interested enough to support the cost of such an investigation. If this were to be done, it would be veil to study 1 005GS Mr. H. A. Thiemann - (2; - August 34, 1951 lead oleate at the same time, sc as to obtain a basis for comparison. The problem here Is one of comparative rates, find the differentiation of that which occurs to a limited degree which is of only theoretical importance (in relation to the underslanding cf tne mechanisms) from that which is of real significance. My prediction is that neither of the compounds to which you refer will be absorbed through the skin at any very significant rate, unless they are maintained on the skin in comparatively high concentrations (several per cent) in some solvent that really helps them, so to speak, to oenetrate the skin, and over periods of hours at a time. It may well be t'iat these materials may rive rise to dermatitis if they come in corf-act with the skin frequently or over considerable periods of time. I can't speak from experience with them, but only from some observation of 3omc cf the o'her lead compounds, as for example, the styphnate. The real problem, if the compounds are to be used in the dry state, or if they are used under conditions that will result in the contamina tion of arear. iv, which work is conducted, will probably be that cf their inhalation. At least, that would es uy g u e s s . Phis problem can be dealt with, of c o r s e , by the same methods that are employed in dealing with otfcc; lead compounds that can give ^ise to dust in the air. Moreover, the detection of hazardous occupational absorption of lead from this soup ce doe3 not differ in principle or method from that associated with the use of other lead compounds in industry. Finally, I should not be -unduly concerned about the special hazards of the use of these materials in the manner you have described, but if I had reason to require real infonnation, I should study, (l) experimental animals exposed to skin contact with rhem - by a method which we have- developed for the purpose, and (2, men, whose occupa tional exposure to lead was limited to rnese compounds (if ruch could be found). I hope these remarks may be somewhat helpful. Cord-allv yours, RAK ef Robert A. K c h o e , M. D. K 8 nn