Document x5KVNmD4rrxLKvkg9J1Mw7xY1

: Bijlii nii July 5, 1967 C-6cz27 Dr. Harriet L. Hardy Assistant Medical Director in Charge of Occupational Medicine Service Room 20B-2J8 Massachusetts Institute of Technology Cambridge, Massachusetts 02139 Dear Dr. Hardy: *" In common with many persons in industries using substantial quantities of asbestos, we are frequently asked for guidance in setting industrial hygiene standards for this mineral. A recent conversation with Dr. Dixon of Fisons (England) suggested that there may be a real difference between the various foxvs of asbestos In regard to their ability to cause mesothelicmata. My first question would then be, is there such a difference? and does it apply to the other less specific tumors of the lung and gastro intestinal tz*act also associated with asbestos? Secondly, If there is such a difference in tumorigenlcity between the various foreis of asbestos, is it of a suffi cient degree to be the basis for a recommendation to management on asbestos handling? Yours sincerely, ORIGINAL SIGNED BY G. J. STORRS a. J. Stopps, M.B.,B.S. Chief, Physiology Section OJS/dyb DUP 1H1765