Document QM4O66Jwx1213nMMGn2aE65eL

DEPARTMENT OF HEALTH, EDUCATION. AND WELFARE PUBLIC HEALTH SERVICE Consumer Protection and Environmental Health Service Environmental Control Administration CINCINNATI. OHIO 49202 REFER TO: February 28, 1969 Mr. Daniel P. Maloney Plant Manager Certain-Teed Products Corporation St. Louis, Missouri Dear Mr. Maloney: As part of our continuing environmental studies of asbestos processing plants we have prepared the attached table giving numbers of people in our study who are exposed to various concentration ranges of asbestos dust. The concentrations are given in fibers/ml longer than 5p so that they may be compared with the standards (ACGIH TLV and British Occupational Hygiene Society Hygiene Standard) expressed in these terms. From these standards one would gather that concentrations below 2 fibers/ml are probably safe, and concentrations above 12 fibers/ml are probably hazardous. You will note that most of the exposures are already below 12 fibers/ml. You should have copies of our reports on your plant in your files. If they have been misplaced, or you wish further information, please let us know. (Where >5p concentrations are not listed you may assume that these are double the >10p fiber concentrations) One can see that less than 10% of the workers are now exposed to concen trations above 12 fibers/ml. If exposures above this level now exist in your plant, we hope that every effort can be made to reduce them. Attachment Howard E. Ayer Chief, Environmental Activities Field Studies Bureau of Occupational Safety and Health CTD017612 O' OsO ai u. X3) u X3 ou Cu * t0o> Vcads) . pa V) a* o CONCENTRATION CATEGORY (> 5p FIBERS/ML) **Unknown ca te g o ry c o n s is ts o f w orkers fo r w hich th e re is no exposure in fo rm a tio n due to ; I) no sam pling o f a g ive n occupation in a g ive n p la n t, 2) an u n id e n tifie d o ccu p a tio n code, o r 3) no occupation in fo rm a tio n g ive n . pj < m CM n* sO in CM H pH i-H m o in oc CO O m 00 as CO CO r*' GO H CM pH rH P*. cr*o. cm <r co 0>| CO CO I CM Cv O uO CO CM m <r mr** v> m O m CM co cmo CM r- O' 00 CO m sO in co n. pH CO m co CM a^ co oo CO co Os O i co CO CM CO CM o o >n CO CM CM OS pH co os 00 pH CO l co px. m P*. co m CM m oo CM CM CM CM rH CM CO so as <r z I---HH u r- :z: o HH b ZZ. '-u ci--u< Sp Id -O4 z-H 0") oM H< d5 zM oz f-H o 2<-t J<Ho H CM "O cca a aoX0)) sO COI c o co H o <J-I c os Vj *cdu > fuH <u a ocfl J3 CTD017613