Document 3N6NXDapn9MO297j73JNjRB66

I < HWfeir-; -- ri-^3 cc; 3#FIftlGAiiTE' j-o;__ lu * P*--Leo<rt - -5c=pr. /Tj )?T) =Aoa\.'--A i-H'-NtCk&LJiUS A>3&G3r03 tH T7*4-C AeF~- (____ LerT&Ll P.-fl x,en. MWtauK., *. PtSfA&rtS bWnto H ------------------rt>--a . 0.--<lyp<nJ> ) -FeFA 3f 1977-- teF.X_____ Ltfrr&u:..Pfiz.<sv~ rv..-Cyp#&utj Aug. %TflTn w 'FAa . ct . 6^-* -A^Uo^, Jc^rjur'^ &~*4 "A* * ^p**t ^ C C&nsGmJ <y( Lttf m*. -**44-*^ -----U4A___ l-6-+*X----__36jMV_ bust /A*-_ ^ ^KcA . ^-tVfcJk. ...& --fkfrsbA CK. DUP 0821320 --yntn^uW^ -s... *A . *V>* "A* <**%* n1r^id>< m ____ MINERALS. PIGMENTS G METALS DIVISION MIZER INC.. 23S E. 42ND ST. NEW YORK. N. Y. 10017 Pebruary 9, 1977 A or... f9Vi*t<A 6*4 sptf- c/c^> Hr. A.D. Cyphers(*/(&/< Plant Manager E.I. DuPont DeNemours & Company P.0. Box 2626 t Victoria, Texas 77901 > y/, U / fj Dear Mr. Cyphers: 9*\ In recent months there has been increasing interest in the subject of talc, particularly with regard to the nature and extent of its asbestos content. Since you are one of our many valued talc purchasers, we feel you should be aware of important information on this subject. The Occupational Safety and Health Administration (OSHA) currently has in effect an asbestos standard which pre scribes that employees may be exposed to no more than 2 asbestos fibers per cubic centimeter of air for an 8-hour time-weighted average, and to no more than 10 asbestos fibers per cubic centimeter at any time. In October. 1975, OSHA proposed to lower the 8-hour time- weighted limit to 0.5 asbestos fibers per cc. and 5 asbestos t.'Lcrs per cc. for any period not exceeding 15 minutes. Vory recently it has been reported that the 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 fibers per cc. In its* October, 1975 proposal,, OSHA defines asbestos to include chrysotile, aroosite, crocidolite, tremolite, anthophyllite and actinolite, and every product containing any of these minerals. OSHA also defines an asbestos fiber as a particulate form of any of these minerals which is longer than 5 micrometers, and has a maximum diameter of 5 micrometers and a length to width ratio of at least 3 to 1. ,f\? FZB fc/7 = \eceivf: ^ viCTCftlA `CP 'Crf.lA1 DU P 0821321 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. 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 doubt wish to review the various provisions of the OSHA standard for occupational exposure to asbestos (29 Code of Federal Regulations 1910.1001) and the pro posed amendments which appeared 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 asbestiform mineral content of the talcs we supply. Pfizer research has developed the most accurate and sensitive method available today of analyzing for asbestos ?~d asbestiform minerals in talc. This method, based on step scanning x-ray diffraction, electron idiffraction, 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 aiid scanning electron microscopy, are as sensitive and as direct. DUP 0821322 -3- Pfizer routinely monitors its' talc production, using this sensitive methodology. Based on many months of evaluation, ve can state that: The California CP talcs which you purchase normally contain between 1% and 5% total tremolite with a fiber content of less than 0.1% by weight (the practical detection limit of the analytical method). The Montana MP talcs which you purchase contain no detectable quantities of tremolite or any of the asbestiform minerals. Thus, you can employ these MP talcs with full assurance that you are fully in compliance with the OSHA asbestos worker exposure standard. Me believe that it is in your best interests and ours that information on this subject be brought to your attention. He trust you will find this letter useful, and that you will follow the OSHA hearings and other developments as they occur. He will continue to monitor these hearings and try to keep you aware of significant developments. If you have any questions, please do not hesitate to contact us. Very truly yours. DUP 0821323 MINERALS, PIGMENTS & METALS DIVISION PFIZER INC.. 239 E. 42NO T. NEW YORK. N. Y. IOOI7 Jbi tA*~*'* August 25, 1977 IsjLcJt/lo c, f JL, Bremin _ BoDerooa __ Sampioc __ S'rth t\yt ^ Mr. A. D. Cyphers, Plant Mgr. -i|.V * 1 E. I. DuPont DeNemours & Co. P.0, Box 2626 O 4r<3L Victoria, 3X 77901 ivju. ^.. "& orL - P T_x_rgte __ Dear Mr. Cyphers: S: CLo f^ Since 1 wrote you in February vitn information on.Pfizer talc products relative to the OSHA asbestos regulation, the National..Bureau of Standards has Issued a lengthy report^) covering their analysis pf"80 industrial talc samples by the OSEA procedures. We suspect this report law have raised additional Questions in your Bind and would like to take this opportunity toexplain Pfizer's position on the subject. The initial request to the KBS from Dr. Morton Com, Assistant Secretary of labor, OSEA, was twofold: 1. "to resolve the variability In the definition of asbestos fibers in talc." 2. "to determine the asbestos content of some 80 talc samples to be provided by OSEA" - using only the OSEA defined optical microscopy method. Prior to comaencing the program, agreement was reached between OSHA and the NBS that the first task "would be a complex, long-term program which would require input from a number of sources both in the private and public sectors" and that the more limited task of determining the asbestos content of the samples would be addressed by NBS first. After completing the 80 sample analysis NBS concluded that: "The variability of these results raises several questions regarding the OSEA procedure, particularly sampling technique, sample hcoogenity and determining fiber morphology. It is the opinion at NBS that, even under favorable circumstances (e.g., homogeneous samples, easily identified fibers, etc.) the existing OSHA procedure is useful only for determining fiber* content and not 'asbestos' content....NBS believes that the resolution of the measurement problem, including the definition and i (1) LaFleur, P.D.j National Bureau of Standards, Institute for Ifeterials Research; A Report on the Fiber Content of Eighty Industrial Talc Samples Obtained From ana using the procedures of the Occupational Safety and Health Administration; Washington, Bl'CT (kay 197/J DUP 08213 hA fe ;K.cuvpICD II' i -2- identiflcation of asbestos, vill be accomplished only by significant changes in the procedure and probably the method as veil." She analysis of talc samples presented special problems to the KBS scientists. Bieir report states, "in the case of talc samples, one exist also Judge vhich of the apparent fibers are talc platelets seen on edge. It is possible to 'roll over' some of these platelets by moving the cover plate slightly, but vhile doing so, one nay also `roll* another platelet into a position vhere it would subsequently be viewed from the edge." Based on Pfizer's experience and the above statement in the KBS report, ve question the conclusion that the CSKA, method is valid even for determining the fiber content of talcs. The fact that even a highly trained microscopist can misinterpret tale platelets on edge is a hey problem which renaina unresolved. Pfizer has maintained a consistent posture since the talc-asbestos issue was first raised. Bather than entering the controversy over the definitions in 29 CIU 1910*1001, ve have accepted the regulation as binding on both users and suppliers of talc and have Invested our technical resources in developing sens itive, accurate, unambiguous analytical procedures to determine the mineral and fiber contents of our talc products. The fact that the KBS report confirms the Inadequacy of the CSKA, test method does not relieve you or your suppliers from complying with the asbestos regulation. To assist you in attaining compliance, Pfizer began in 1973, as part of our qual ity assurance programs, to routinely monitor our talc ore as It is mined and our finished products using the most sensitive analytical methods available. Based on this `extensive testing, ve are pleased to be able to reaffirm these facts about Pfizer talc products) 1. Montana (HP series) talcs contain no detectable quantities of tremolite or any of the other aabeatifora minerals. 2. California soft (CP series) talcs normally contain between l and 5 total tremolite with a fiber content of less than 0.1Jt by weight (the practical detection limit of the best analytical method). 3. California hard (CF series) talcs contain 20 to 30 by weight total tremolite of which more than half meets the OSHA criteria for fibrous asbestos particles. Therefore, when using these C7 tales, you should take appropriate measures to insure compliance with the asbestos regulation. Ve are confident that the regulatory agencies* will soon agree upon a more precise method and that the controversy surrounding asbestos in talc vill be resolved. 3h the meantime, you cam be assured that Pfizer will continue its rigid quality con trol program to Insure that the talc you buy from us is as represented. Weiftll". continue to follow the developments and will advise you of significant changes as ' they occur. Ve invite you as a talc consumer to contact us anytime ve can be of assistance.