Document v16ZBJz0kmZ6EkVa2VZmbDJXm

FILE NAME: Kaiser Gypsum (KG) DATE: 1977 Feb 7 DOC#: KG089 DOCUMENT DESCRIPTION: Letter to Kaiser Gypsum 2-23-77 oc! R. H. Ber R. J . Wiborn " " MlftlfeRAiS, PGMEWTS O RATALS D V iSIQ N O PPJZlrR tN O,, 235 C.4S-HUtVT, NEW VORK, H, y. 1>D13 February $, L977 y' .O a Mr* V,E, Ov Kaiser Gyr 300 LaJcas Oakland, tJJ ' TfiLC. U I>ear Hr In recel the subje. nature' a axe one o you shouL. subject* g interest in gard to the * Since you s twe eel ion on this IChe Occupation, Stratton (QSBA) currently hasj . ard which pre- scribes that jer___ no m_o_r_e than 2 asbestos fibbers pex* cubic centimeter of air for-an S-hour tirae-vAeighfced average , and to no more than 10 asbestos fibers per cubic centimeter at any time. In October , 1975v OSHA proposed to lower the 8-hour time- weighted limit to 0,5 asbestos fibers per cc* and 5 asbestos fibers per ccr. for ahy period not exceeding 15 minutes* Very recently it has been reported that th National Institute for Occupational Safety and Health has recommended the respective permitted exposure levels be limited even further - to 0/1 asbestos fibers and 0,5 asbestos fibejrs per cc< In its? Octpbier, 1975 propos#!, 0SK& defines asbestos to include chxysjotili araosite, Crocidolite, fcremo!itef anthopliyllite and actinolifce, and every product containing any c these minerals, OSHA also defines an asbestos fiber as a pairticulate form of any of these minerals which is longer than 5 micrometers, and has c maximum diameter of 5j micrometers and a length to width ratio of at least 3 to 1- H A R 1 21604-3745 2138 T ,4 _ c r 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 employes exposure must be reduced* as low as is feasible, OSHA proposes to hold hearings on tha entire subject, but until those hearings and subsequent deliberations take place there will continue to be considerable uncertainty, Nevertheless it is prudent for your workers, while using any talc which might contain asbestos fibers, to avoid creating dust to the extent possible* 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 implemented. You will no.d^ubt wish to review the various provisions r of the CSKA standard for occupational exposure to asbestos (29 Code of Federal Regulations 1910.1001) and the pro posed amendments which appealed in the October 9, 1975 issue af 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 u s o talc* However, we can provide information on the asbestiform mineral content of the talcs we supply. Pfizer research has developed the most accurate and sensitive methjed available today of analyzing for asbestos and asbestiforn 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 0,5% and fibrous amphiboles, such as tremolite, at levels as low as*0.1% 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 r. -3- TflCc 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 purchase normally contain between,1% and 5& total tremolite with a iifcer content of less than 0.1% by weight (the practical detection limit of the analytical method.). We believe that it is in your best interests and ours that inormation on this subject be brought to your attention. V?c trust you will find this letter useful/ and that you will ollow the OSHA hearings and other developments as they occur. We will continue tD monitor these hearings and try to keep you aware or significant developments. If you have any questions, please do not hesitate to contact us* r Very truly yours,, ilPB:sp /, CTT-iff? P&A*'Tw- 7^ C > t i: $ & t* ,7\ /^o** ------ -------~&veuS}Otfoie f-------7*9#*? ^ ?ao xr 2 ^ * //**, x; t/ ^ A t*/ . ,, - r 7V./*?<>, = 9 y *?*, * Z'i 3 fvKfos I Cst gLofifi t !**'/**,') C- M * . -* HAR121504-3747 2240