Document EmDJV9V2rppLZB4mYadnYXmL0

/ ft' December 10, 1973 TO; MEMBERS OR THE CTFA TALC SUBCOMMITTEE 5, SCIENTIFIC ADVISORY COMMITTEE: Attached herewith and submitted for your reading and comments is a finalized submission of the report of the CTFA Talc Subcommittee which we wish to submit to the Food & Drug Admini stration. Please read at once and, likewise, call me at once if you disagree with any of the content matter. In view of the very short time left to process this submission, your immediate attention is of paramount importance. Thank you REPORT OF CTFA TALC SUBCOMMITTEE ON METHOD TO DETECT CHRYSOTILE AND TREMOLITE IN TALC. December 10, 1973 The Scientific Advisory Committee of the Cosmetic, Toiletry & Fragrance Association, 1625 Eye Street, N.W., Washington, D.G. 20006 at a meeting held on September 2, 1973, designated that a subcommittee be set up to study the optical microscopic method proposed by the Food and Drug Administration. This method was published in the Federal Register of September 28, 1973. The present membership of the CTFA Talc Subcommittee is shown on an attached sheet. . At the first meeting of the Subcommittee, it was agreed to submit several samples of talc to members who volunteered to apply the FDA proposed optical microscopic methodl The following talc samples were distributed without identification - except for randomly applied and non-duplicated code numbers: Italian Talc Grade 1615 Montana Talc Source P Montana Talc Source F Vermont Talc Grade #66 Alabama Talc No. Carolina Talc Grade 643 In addition, a sample of Italian Talc spiked w/w with 1% ebrysotile and 0,15% tremolite was sent to each participant. The participants were aware that the sample was spiked, but did not know the pen .,,.-ctaga of spiking. The attached table summarizes all reports submitted: "2- Sample 'No. of Fibers With R.I. Greater Than 1590 No. of Fibers With R.I. Less Than 1574 Status With Regard to Pro posed FDA Method Mrs. Lucy McCrone, McCrone Associates for Chesebrough Spiked Italian Montana-Pfizer Alab ama Vermont No.Carolina' Montana-Ferry 320 120 0 0 0 0 0 16 Passes 0 Passes 0 Passes 0 Passes 0 Passes 0 Passes 0 Passes Mr. Harold Stanley of Pfizer V O Italian /''Hi*100 Montana-Pfizer 1Q Montana-Ferry 100 Alabama r w 100 Vermont ^ 100 No. Carolina /"s*100 >100 >100 >300 >100 >100 Fails Chrysotile Passes tremolite Fails Chrysotile Passes tremolite Fails Chrysotile Passes tremolite Fails Chrysotile Passes tremolite Fails Chrysotile Passes tremolite Fails Chrysotile Passes tremolite Mr. David Hamer of Johnson & Johnson Italian Montana-Pfizer Montana-Ferry Alabama Vermont No. Carolina 0 1 25 0 0 0 0 0 0 0 0 0 Passes Passes Passes Passes Passes Passes Spiked Italian Dr.- John A. Refiner (U. of Conn.) for Avon 632 12,930 220 1,114 Fails Chrysotile Passes Tremolite Fails Chrysotile Passes Tremolite 3- - 'Sample , No. of Fibers No. of Fibers With R. I.- Greater With R.I. Less Than 1590 Than 1574 Status With Regard to Pro posed FDA Method Dr. John A. Reffner (U. of Conn.) for Avon Cont'd Montana-1 Montana-^ Alabama Vermont No. Carolina 0 5,844 13 9,281 26 15,125 41 165 14 11,852 Fails chrysotile Passes tremolite Fails chrysotile Passes tx'emolite Fails chrysotile Passes tremolite Falls chrysotile Passes tremolite Fails chrysotile Passes tremolite Dr. Tryggve Baak of United Sierra Spiked Italian Montana-I Montana-^ Alabama Vermont No. Carolina 3,000 1,000 0 0 0 0 500 ; 2,000 0 0 0 0 0 0 Fails Passes Passes Passes Passes Passes Passes RLchard E. Stevens of Ernest F. Fullam, Inc, for WhittakerC&D Italian Montana-I Montana- H Alabama Vermont No, Carolina 8,250 18,000 29,250 21,825 3,225 20,850 1,350 450 5,200 6,075' 675 6,000 Fails chrysotile & tremolite Fails chrysotile & tremolite Fails chrysotile & tremolite Fails chrysotile & tremolite Fails chrysotile & tremolite Fails chrysotile & tremolite Spiked sample was not run. AAAKBPXLF CF~BALL~8 4- - Sample No. of Fibers No. of Fibers With R.l. Greater With R.l. Less Than'1590 Than 1574 S.tatus With Regard to Pro posed FDA'Method Mrs, Lucy McCrone of McCrone 'Associates for Kolmar Italian 53 0 Passes Montana-I 0 0 Passes Montana-H 0 0 Passes Alabama 0 0 Passes Vermont 0 0 Passes *No, Carolina 0 0 Passes Spiked Sample 488 16 Passes *Sample noted to contain some fiber bundles which are rolled up talc plus some non-fibrous tremolite The following participants examined their samples but were unable conscientiously to count particles with confidence, therefore, did not report numbers : Miss Marie Jones for Dr. G. Cohen - Bristol-Myers Products Research Lab Mr, Salvatore DiBianca - The Mennen Company Liberty Mutual: InsuranceCo., Research Center-- forKolmarLaboratories Mr. John Facq - The Colgate Palmolive Company, Research Center The table reveals strong inconsistency between results obtained by the different scientists applying the method to the same group of coded talc samples. This inconsistency is the result cf problems encountered in the me.thodologv. 1. The alpha refractive index of talc - one of the two indices exhibited by talc, plates standing on edge - varies in. value between .1.539 and 1.550^. This in combination with item 2, below, m ly easily result in the mis-classification of such plates a 3 ''fibrous, less than 1.574" and therefore chrysotile. Dr. Reffner of the University of Connecticut, in his report to Avon, admits that this factor is paramount - "counts for chrysotile are high since (talc) edges will often be mistaken for fibrous particles". 2. The immersion method for the determination of`relative refractive index becomes unreliable when applied to extremely small (ca. 1 pm.)particles. This is due in part to the fact that particles around lyP in width approach the limit of resolution of. the human eye when, both size and contrast are considered, especially when applying the Becke line technique prescribed. This will 5- - 2. cause eye fatigue-and resulting errors. Thus, a fine talc shard or plate on edge may be easily mistaken for an asbestos fiber. This applies to both the chrysotile and atnphibole - portions of the test. 3. It is quite likely that chlorite - a mineral of varied compo sition `commonly found in pharmaceutical grade talc - would be incorrectly identified as tremolite. Refractive indices for chlorite vary in the range 1.57-1.66^. 4. The examination of a sample of one milligram dispersed on a single microscope slide presents the investigator with a preparation which is too dense for a petrographic study. 5. The method is laborious and time consuming. Dr. Reffner quotes .an analysis time of about five hours per sample and at JOHNSON & JOHNSON the investigator (D. H. Hamer) estimated at least two or three hours. 6. Dr. Walter C. McCrone in an earlier letter to the FDA suggested that there were relatively few scientists in the country who could use the method effectively. Scientists at Bristol-Myers, The Mennen Company,Liberty Mutual and Colgate-Palmolive had great difficulty in following the method to conclusion. 7 . The proposed FDA method implies that all fibrous particles in talc having optical properties similar to those of asbestos minerals are in fact asbestos. This is probably an unwarraiited assumption. REFERENCES: 1. Deer, W.A., Howie, R.A., and Zussman, J., Rock-Forming Minerals, Vol. 3, p. 121 (1962). 2. ibid, p. 131. ***************** We have concluded that the method published in the Federal Register does not provide a truly reliable means for the detection of asbestos in talc. It results in both false-positive and false-negative findings. It is also tedious and may consume as much as one half day per sample. The subcommittee urges that the Food and Drug Administration defer finalizing the proposed optical microscopic method and proceed into a Phase II program which would combine FDA and Industry in a strong effort to develop a truly reliable method for measuring chrysotile content in talc. We are confident that the detection and estimation of fibrous tremolite can also be done, if necessary, as a fringe benefit, at the same time. 6- - We estimate that a satisfactory method will take at least six months to a year, to develop. We suggest a close liaison between E'DA and industry in this all-out effort with updating reviews to take place as frequently as necessary. Review of Alternate Methods The CTEA Talc Subcommittee has reviewed several methods to detect chrysotile and tremolite in talc, including modifications of the optical microscopic method. These are listed with comments.' * 1. Optical Microscopic Method - may be used.with some modification. ' Possibly better selection of R.I. liquids and reduction of sample size per slide. 2. X-ray Step Scanning - A good method for detecting tremolite if we could accept about 0,2% as the threshold of detection. It does not distinguish fibrous from non-fibrous tremolite. The simultaneous detection of chlorite makes method impractical for chrysotile. 3. X-Ray Step Scanning -f Optical Microscopy - Acceptable as in //2 above but the optical method continues to present the dilemma in reliable identification of chrysotile. However, this does not rule out a major revision of the optical method to do the chrysotile .... identification and counting,.... ......... .. ... A. X-Ray Scanning - The problem of chlorite interference in the detection of chrysotile is present in all x-ray procedures thus far available. It is .the detection of 1% tremolite (both fibrous arid non-tiurous}, 5. Differential Thermal Analysis - This procedure is capable of detecting chrysotile at the 1% level, however, it will not detect tremolite. 6. Scanning Election Microscopy - This procedure is not capable of identi fying asbestos. Even with energy dispersive analysis, completely satisfactory identification is not possible. 7. Transmission Electron Microscopy + Blectrcn Diffraction - This appears to offer the best, most reliable method and is probably capable of detecting chrysotile and tremo3ita (fibrous), both at a level of 0.1%, It is estimated that an installation would cost about $130M +, and is obviously prohibitive for the small manufacturer who uses talc. The amount of talc sample examined by this procedureis miniscule. 7- - Summary The CTFA Talc Subcommittee has completed Its review of the Optical Microscopic Method for the Estimation of Chrysotile and Fibrous Tremolile in Talc, which appeared in the Federal Register, voi. 38 (No. 188),(p. 27076 September 28, 1973). It recommends postponement of the finalization of the proposed regulation on talc. In addition, a collaborative effort between FDA & industry to resolve a satisfactory method of estimating chrysotile and tremolite in talc, is recommended, with periodic liaison reviews to monitor the project status. A task force of industry experts has been designated to pursue alternate methods. We invite FDA to participate in collaboration with the task force. George 1). Sandland Chairman CTFA Talc Subcommittee GWSidd