Letters Received to Arthur Roeder [A. Roeder], June 12, 1924

R. L. M. C. INTERIOR MEMORANDUM Date Subject For Attention of Answering Memo. of tests show that Chis dust is exceptionally fine and will UNTED'S not settle even in still air readily. If so how can it re- RADIUN main settled in this painting room where there are continu- air currents due to open windows vibrations and the moving of individuals about the room. Would it stay in suspension and be caught in the clothes of individuals, It woukd be very simple e for 18 to rig up is little apparatus which would enable us to sample the air and gather the dust which could be subjected to: radio active determinations in our own laboratory. On page 12 near the bottom Dr Drinker emphasizes that feet that so far the results of the tests are negative because of the "extrem- 1y small quantities of radium combined with the zine sulphide. It does not seem to me that the fogging of dental films is really indicative of over exposure. In view of the quantity of radium handled about the plant and the extreme sensitiveness of these films a film might become foggeg when a small quantity of highly radboactive material wase brought nearby the exoosure to which an individual might be subjected to in this shortytime would be considered harmless. We know that a piece of good ore placed upon a film would cause that film to become fogged yet we would hesitate to say that it would be harmful to carry the ore even for a consideral ble length of time. Other application plants must have these same conditions of dust and exposure why has not this trouble resulted els where. In the blood tests we see that the individuals who are subjected to an exposure many times greater than any operator really have a better existing condition than these operators. In the crystallization department the exposure is not only external but in pipetting solutions emanations are bound to be inhaled ana maybe even drops of very active solutions. This would also bring up the question. of safety of emanation water machines. Yet the mouth conditions are good. Mr. Bilstein who hi B had varied experience with both radium and zine has recently had a tooth extracted and to date has suffered no ill ef ects. Dr Drinkers 8 mparis ns are made with normal indidual and i believe this should pe made on a basis of the average industrial worker. Possibly this is why the Life Extension Instutedid not comment on this finding because this con- dition is common amongst industrial women workers. They might be able to furnish us with data on this point, in viww the fact that they carry on numerous examinations for industrial concerns and insurance companies. It is quite possible the to living conditions of indiduals