Document 99ZDGBXXQy5aDN3DgaE9ExrO6

FILE NAME: RT Vanderbilt (RTV) DATE: 1974 Oct 9 DOC#: RTV256 DOCUMENT DESCRIPTION: Memo RE FDA Optical Methods for Counts of Asbestos Minerals Meeting OSHA Definition in 4 RTV Talc Samples . Johns-Manvie Infernal C o r r e s p o ; R. S. Lamar - RS.D Dato; October 9, 1974 F.-om: V. E. Wolkodoff - R&D Coi"- Distribution at End of Memo Subject: pDA OPTICAL METHODS FOR COUNTS OF ASBESTOSMINERALS MEETING OSHA DEFINITION.IN FOUR TALC SAMPLES PRODUCED'BY'R; T. VANDERBILT COMPANY Through J. P. Leineweber ,^-Rr~pT-~arter has requested that this memorandum listing asbestosriBferSQOuhts-on-, four samples-of tdlc. from R. ^VanderbiJit>ji^pany;(submitted by Charles Wagner Company) T ^ - e n ^ M s d e s k on Friday, October 11, 1974. The R. T. Vanderbilt Company talc samples are identified as follows: 1. Lab. No. RC-74256-1 2. Lab, No. RC-74255-2 3. Lab. No. RC-74255-3 4. Lab. No. RC-74255-4 . Nytal 200 Nytal 400 Asbestine 3X Asbestine 325 ^Ihcerthe samples are extremely complex, due to types of asbestos.3ihsr. present, the J-M modif ied-optical method ^RralthTbc befusedyfor ,each,.determin'ation\;but.vrather we issued-on August 20*, 19`73. The' :JpM'imbdiiiedy,optical technique, however', was used, on ea'bh^sai^L^sVJcl'arified -'Si Millipore membrane) in con'junction :with^Zernecke.phase contrast microscopy as a check on thetotal number of fibers in each sample. In all tests'-/,only fibers-meeting OSHA definition were counted; that is, at least a 3:1 aspect ratio rand fiber lengths have to be at least 5 microns or longer. 4 Total number of (asbestos fibers^per mg in each sample: a. Nytal 200 b. Nytal 400 c. Asbestine 3X a. Asbestine 325 1,055V 00,0'-fibers/mg 2.146.000 fibers/mg 1.460.000 fibers/mg 1.526.000 ibers/mg Fibers per mg of each ^ for the four k RTV 5064 CRMC-ELS-005 \ 64 R . $. Lamar (2) October 9, 1974 samples studied are as follows: SAMPLES .Nytal 200 Nytal 400' Asbestine 3X Asbestine 325 TREMOLITE 6Q4)Q0Q/mg 1,931,000/mg 876,000/mg 992,000/mg CHRYSOTILE 3QQ,000/mg 86,000/mg 561,000/mg 503,000/mg ANTHQP HYLLIT -- 151,000/mg^ .. 129,000/mg.; 23,000/mg 31,000/mg The.predominant fiber! in.;each sample .is Tremolite which can be somewhat .blocky,'.With clipped end's i s ^ v e r y "harsh/ but most are:'n%r,rbw^andA'r.igdV:,f'ibers. ;;:The'jGK^,so.t;i;le ranges from silky ,,(very- small'percentage),, bubales of few fibrils, and bundles1containing numerous/f ibril's . In general, the Chrysotile is .considered medium-harsh.to harsh. The Ahthophyiirte is characterized by ;having very narrow diameters, being extremely rigid, being almost spear-like since individual fibers can.show,one-end as acicular (needle-like)' and others show a double'termination of acicularity. By transmission electron microscopy (TEM), six plates were taken of each sample. One print of each-sample to show at least la few Gh'r'sotile. fibers- are attached; and the magnification is 13.000X. At this magnification 1.1 cm equals one micron. The TEM plates on file are as follows: a. Nytal 200 b . Nytal 400 c. Asbestine 3X d. Asbestine 325 TEM Plate'NOS'. 2301 -A-FTEM Plate Nos. 2302 A~F TEM Plate Nos. 2303 A-F TEM Plate Nos. 2304 A-F All plates were taken at 4400X, and after enlargement for prints, the magnification would be 11,00X. All TEM plates were taken on our RCA EMU-3B electron microscope. We had planned to use a better model, Philips 200, at The Denver Research Institute for greater CRMC-ELS-005165 R. S. Lamar October 9, 1974 clarity, better resolution, obtain plates ,at higher/magni--. ^ fication and do selected area electron-diffraction to prove the identity, of-the asbestos. ,minerals,, (which cannot be done on:our ,RCA :model), but the instrument at,DRI was,.. not available for our use at the time; and in all probability^^ even if available, the work could not have been finished by October111', 1974, since the optical work took a great deal of time. 7. If better TEM micrographs are needed with selected area electron diffraction.patterns for your FDA presentation, and if youtsomehow can get additional time before the presentation, I Will' make arrangements for our use of the Philips 200 electron microscope at DRI. ]jt Z, {/Jo'lks-l/jfj V. E. Wolkodoff Applied Research Section jc Distribution: R. P. Carter 4N e . m . Fenner - 4M Paul Kotin, M.D. - 4N W. B. Reitze - 4N F. J. Solon, Jr. - 4N G. l . Swallow - 4N a . c. F. Finkbiner, III - 5W j. a . McKinney - 5W . H. R. Keefe - `2W P, A, Martinson - 2W C. w. JL.. Sulewski VanDerbeek - 2W - 2S R. G. Riede 2S FJ .. L. P. Pundsack Leineweber W. C. Stfeib A. J. McArthur S. Speil l V|| Vsfifi :|| NOTEBOOK 4454 pp. 70-77 CRMC-ELS-005166 'I'l.'M t4y L.t 1 !,m- J ,li] i 1 1 ,uuex CRMC-ELS-005167 CRMC-ELS-005168 I i o n - 2 3 (i 3 0 1 ,0oox CRMC-ELS-005169