Document qa7RQNpvV6JqgdJ2njd7VBwkn

* UN'IT'ED states GYPSUM COMPANY 3 0 d w/t ST ADAMS S T 8 T rOjt ^ Dr. A. J. TorvCd Director Trodo Poundation Saranac laboratories Saranac Late, Hev Tort Dear Sir: We would like to get your opinion M to the possible health hazard that night exist In the handling or Perlite. for ve are Installing perlite rode processing plants and ezpsndln^plants at some of our gypsum opera* tioas. According to our information, perlite Is a p-iw but there Is no quartz present as disclosed by the Petrographic microscope. She chemical analysis of one of the deposits Is: SI Og P2 3 ai2 03 Ca 0 Mg 0 r2 0 Hgg 0 S 0* Ignition Loss 71.5** 1.40 13.44 1.06 o.sr 4.46 3.21 0.02 4.04 100.04$ The ore is reduced by crushing and screening to a size comparable to sand, and then subjected to high heat In a direct fired furnace and expanded, so vhlle the ore nay veigb 100 to 120 pounds per cubic foot before expansion, the expanded material weighs about 10 pounds per euble foot, ttere Is a certain amount of dust mode In the handling of the ore, and In the expansion process. Proa the work that you hare done for the company in connection with gypsum and gypsia combined with silica, and also the work on asbestos and glass wool, I sa of the lapresslon that perlite would net be particularly harmful. She usual precautions to keep the amount of dust in the air down within the usual requirements for s nuisance dust of 50,000,000 particles per euble foot vould be all that vould be necessary for us to do, but ve certainly vould appreciate your thoughts on the natter. Tours very truly JVB:IC G0300i TOTTED STATES GYPSUM COMPACT At ^ J. jOfiutler Serrlce Manager WHClf MJfAlCH OtVtlOM IT TI #, lAril tUUOINO MATtt'Alt