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AMERICAN CONFERENCE FFO 1976-77 ae FFO 1976-77 3500 Tepe N Logan Lersing bien cen Tat 517 323- 323- tel Sh mee nhs . oWEAKt te > WEAK GOVERNMENTAL INDUSTRIAL HYGIENISTS .... BOBBY F CRAFT P Vice Chairmen Nohona !! ** Occluat oral Sal & Health Robert lah Lahor 4878 Comba Park ~ Cinturnal Ohio 45220 Tel 513 644-2147 644-2147 DAVID M. TRAYER Vice Chair need Termosso laro Authority Breer Does Bang Musicals Musicals Dua 35650 Tel 2051383.463 Ext 311 WILLIAM DI KELLET Secretar Treasurer National Institut Institut for Occupan Occupan Sataty & Health Bo 1937 Cincinnati Ohio 45201 To 573-694-8487 573-694-8487 Mr. R.N.Miller President Windsor Minerals Inc. Windsor Vermont 303 Mill St. Belmont Ma C" DONALD M. ROSS Chel Health Protection Branch Energy search & Desalopment Admin Washington DC DC 45 MRS KIM STEWART STEWART STEWART Manage Publical ons Office O b 937 Cincin y513,875-0312 March 28 1977 Dear Mr. Miller This is in reply to your recent request for information on the year the TLV of 20 mppef for talc was recommended - I do not at present have the files of the TLV Committee , ~ but in checking back on the Transactions of the ACGIH this value is given in the 1948 issue It was probably not much earlier since a comprehensive list of TLV's was not prepared before 1945 or 1946 And during the first few years not too much attention was given to mineral dusts with the exception of free silica For over 20 years only one type of talc was mentioned The 1962 and 1966 Documentations state that the limit refers to talc its commercial sense but is based on studies of talc with a substantial 10 tremolite content I In either 1969 or 1970 the differentiation between fibrous and fibrous asbestiform tales was introduced The TLV for the latter type was retained at 20 mppcf that for fibrous talc was and is currently based on the fiber count It is recommended that in some cases it may be advisable to count both dust particles and I might point out that the TLV for nuisance dusts which are generally the least harmful of all particulates is only 30 mppcf A few years ago the limit for these dusts was nearly twice as high 50 mppcf they had Until many items no legal standing provisionally in the TLV list were adopted by although many states used them OSHA either as guides or more rarely with the force of law Very truly yours Elkins HerB. rElkyins - Chairman TLV Committee 0067260061 7261 JNJ 000327919