Letters Sent to Rollin H. Stevens, February 3, 1930

February 3rd,1930. Dr. Rollin H. Stevens, 1429 David Whitney Bldg., Detroit, Mich. Dear Dr. Stevens: I am glad to herewith confira in letter form the matter discussed with you personally on Thursday January 30th: From 1916 to 1925, the United States Radium Corporation or its predecessors maintained an application plant for applying radioactive luminous material to watch, clock dials, etc., during which period there were probably employed a total of approximately 400 girls. The radioactive luminous material was applied to the numerals of the dials with small camel's hair brushes. As you realize, this operation is rather a delicate one and requires considerable skill. The brushes had to be well "pointed* and to do this a good many of the operators used their lips, although there were other nethods provided. While the practice of "pointing" the brushes with Cheir lips was forbidden on account of sanitary reasons, still the girls continued the practice with our knowledge. Early in 1924, a dentist in Newark called to our attention the fact that he felt thore was an industrial hazard existing in our work. lie immediately had a study made, with reference to the materials used as well as working conditions, by the Public Health Department of Harvard. Due to the fact that they could not attribute a similar condition which they found existing in a number of our employees to any particular cause, they advised us that they would look upon the radioactive constituents of our naterial with suspicion, and advised certain recommendations which tré immediately put into effect. lie followed this up by discussing the possibilities of the radium presenting a hazard, with both medical and scientific nen versed in the subject of radioactivity, and they both felt that the conclusions drawn by the public Health School of Harvard were rather far fetched. We hnd other investigations nade, somo of which indicated that it was questionable whether there was an industrial hazard existing at our plant. However, as tine progressed and more data and information became available regarding the conditions existing among certain of our employees who had been engaged in this practice, our attitude changed and we recognized that there probably was a hasard connected with this work. The seat of the trouble eould be traced back to the practice of "pointing" the brushes with the lips, thereby serving as a means of introducing the material into the system. The radioactive luminous material consisted of phosphoresent zine sulphide, which is primarily zine sulphide of a special crystaline nature, containing one (1) part of cedmium sulphide to 820 parts of sine sulphide, one (1) part of copper sulpidide to 7150 perts of zinc sulphide, and one (1) part of manganous sulphide to 2300 perts of zine sulphide. The radium or