Document ZOOY9Ywv46Mroqyon2V4keKV

FILE NAME: Pfizer (PFIZ) DATE: 1977 Feb 9 DOC#: PFIZ002 DOCUMENT DESCRIPTION: Letter 2-23-77 cc! R. H. Berbyv/ "' s R. J , Wiborn Mr. W.E. Oustferman Kaiser Gypsum: 300 baha-side Dr. Oakland, Ca. 94604 T/U C a i Dear Mr., QusSerman: In recent raonjths there has been increasing interest in the subject cjf talc, particularly wi t h regard to the nature' and exjfcent of its asbestos content. Since you are one of oust many valued talc purchasers, we feel you should be aware of important information on this subject. The Occupational Safety 'and Health.Administration (QSHA) currently haai in effect an asbestos standard which pre scribes that employees may be exposed to no more than 2 asbestos ffjbfers per cubic centimeter of air for-an 8-hour time-weighted average, and t o n o more than 10 asbestos fibers per cubic centimeter at any time. In October, 1975-, OSKA proposed to lower the 8-hour timeweighted limit to 0.5 asbestos fibers per cc. and 5 asbestos fibers per cc. for any perio'd not exceeding 15 minutes. Very recently it has been reported that the National Ihstjitute for Occupational Safety and Health has 'recommended the respective permitted exposure levels be limited even further - to G.*l asbestos fibers and 0.5 asbestos fibejrs per cc. In. its' Octpbjer, 1975 proposal, OSKA defines asbestos to include chrysjotile, amosite, Crocidolitb, tremolite, anthophyllite andi actinolite, and every product containing any of these minerals. OSHA also defines an asb.estos fiber as a pairticulate form of any of these minerals which is loncfier than 5 micrometers, and has a maximum diameter of 5j micrometers and a length to width ratio of at least 3 to 1. i i / fn'yc: . . r ' **2- T A lcl. The reason for the proposed revision of the standard for occupational exposure to asbestos is that asbestos, in its several commercial forms, has been associated with the production of not only asbestosis but a variety of cancers and malignancies. Because of the many unknown factors, including the variability"of individual response to carcinogens and the absence of data to establish a safe level, OSHA has concluded that employee exposure must be reduced"as low as is feasible, OSHA proposes to hold hearings on the. entire subject,, but until those hearings and subsequent deliberations take place'there will continue to be considerable uncertainty. ,r. Nevertheless it is prudent for your workers, w h ile using any talc which might contain asbestos fibers, to avoid creating dust to the extent passible. Monitoring procedures .should be employed to determine dust concen trations under working conditions. Where appropriate, dust control equipment or use of respirators should also be considered, and worker training programs implementedfou will no.dcjjubt wish to review the various provisions of the OSHA standard for .occupational exposure to asbestos (29 Code of Federal Regulations 1910.1001) and the p r o posed amendments which appeased in the October 9, 1975 issue of the Federal Register." Since we have no control over' the conditions of use of talc products in your plant, it is not possible for us to indicate the airborne fiber concentrations which could possibly result from your use of talc. However, we -can provide information on the asfcestiform mineral content of the talcs we supply. Pfizer research has developed the most accurate and sensitive mat hied available today of analyzing for asbestos and asbestiform minerals in talc. This method, based on step scanning x-ray diffraction, electron diffraction, and transmission electron microscopy, permits identification of' true chrysotile asbestos at levels of 0,51; and fibrous amphiboles, such as tremollte, at levels as low as'O.lfc in the talc. No other identifi cation methods in-use today, including optical microscopy and scanning electron microscopy, are as sensitive and as direct. i- ! F. ; n HAR121604-3746 ' 2239 CT.-.S3U 3- TflLc Pfizer routinely monitors its' talc production using this sensitive methodology. Based on many months of evaluation, we 'can state that: * The California CP talcs -which you purchasa normally contain b e t w e e n .1% and 55 total tremolite with a 'fiber content of less than 0.1% by weight (the practical detection limit of the analytical method). ffa be'lieve that it is in your bast interests ar.d ours that information on tlu.fi subject he brought to y o u r attention. i Vie t rust you will find this letter useful, and that y o u will follow the OSHA hearings and other developments as they occur. Ke will continue to monitor these hearings and try to keep you aware o significant developments. , If you have any questions, please do not hesitate to ; contact us, . j j Very truly yours, ! 1I JPBssp SjYp ^ ^ S o a <?) P&.A*T w 7*aic J+ffiC-nTb - - " A-c.c jS>& // ---------------- / .... fi-T f i ~ eg-V-. 7 Bstex. A t______ ~bv<u.Popfose z ,S " S % x. - f T f Aie,, 2, 'Ll % X i * A'/** = 7 7/ ^ , 3 V=vtJeT^ ZfrAfoX? K t** T/+h,0 - 2 2- 7 /rt> t,, 3 r/w x Sir/*** ~ / o/) i? 7ific i "'ibafjnt 4-- M A H J i i ! HAR121604-3747