Document JvDQyN5oLnQyxZpb70ZM4bxNe

Inter Offlc* P*ronn*l and Organization Staff Mr. Frank Serbus Saline Plant April 19, 1917 cc K. lee Subject: Talc Dust Exposures -- Permissible Occupational Exposure Limits This nemo vill clarify issues regarding permicsiblo occui'-ational exposures to talc dust vhich is of respirable sice dimensions. Previous industrial hygiene studies done at the Saline Plant erroneously classified asbestos-free talc as a nuisance dust. We regret this error on our part, but wish to emphasise that talcosis -- the dust disease of the lunps resulting from excessi/e exposures to respirable talc -- is chronic in nature, that is, the lenpth of exposure to result in lunp scarring and fibrosis normally is many years of almost daily exposures to hiph dust levels. To reemphasise, asbestos-contaminated talc can present occupational hazards, but asbestos-free talc should not be regarded as a benign material. It should be noted that the quality of talc used at Saline is of the highest quality we have analyzed at all Ford plants; it is essentially asbestos-free. The permissible exposure limit, or threshold limit value, for a ;bestos-free talc is 20 mppcf (millions of particles per cubic foot of breathing .one air). This is calculated as an 6-hour time-weighted average exposure to dust. As respirable dust, this closely approximates our recommended exposure level ' 3 mg/li-5 (milligrams of dust per cubic meter of breathing zone air), not 15 ng/lr ret mmended for nuisance dust. Photocopies of pertinent articles are attached which may be of : describing talc dust exposure hazards. i -erest in Roger L. Uabe'... Senior lndust..-.:.al Hygienist Industrial Hy{ iune Section Employe Health Services Department .007 05? 1 PRODUCED BY FORD