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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.C. 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 method. The following talc samples were distributed without identification - except for randomly applied and non-duplicated code numbers: Italian Talc Montana Talc Montana Talc Vermont Talc Alabama Talc No. Carolina Talc Source I Source II -. . In addition, a sample of Italian Talc spiked w/w with It chrysotile and 0.15% tremolite was sent to each participant. The participants were aware that the sample was spiked, but did not know the percentage of spiking. The attached table summarizes all reports submitted: Final Report Sample Spiked Italian Montana- I Alabama Vermont No.Carolina Montana- n 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 320 120 0 0 0 0 -0 16 0 0 0 0 0' 0 Passes Passes Passes Passes Passes Passes Passes Mr. Harold Stanley of Pfizer Italian Montana- I Montana- II > Alabama Vermont No. Carolina Spiked /-~ 100 ~ 100 ~100 ~100 /<-* 100 /-V 100 < 1000 > 100 >100 >100 >100 >100 >100 >100 Fails Chrysotile Passes trenolite Fails Chrysotile Passes tremoiite Fails Chrysotile Passes tremolite Fails Chrysotile Passes tremolite Fails Chrysotile Passes tremolite Fails Chrysotile Passes trenolite Fails Chrysotile Passes tremolite Mr. David Hamer of Johnson & Johnson Italian Montana- I Montana- II Alabama Vermont No. Carolina 0 1 25 0 0 0 0 Passes 0 Passes 0 Passes 0 Passes 0 Passes 0 Passes Spiked Italian Dr. John A. Reffner (U. of Conn.) for Avon 632 12,930 Fails Chrysotile Passes Tremolite 220 1,114 Fails Chrysotile .5tasses Tremolite 3- - Sample , Montana-I Montana-H Alabama Vermont No. Carolina 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. Refiner (U. of Conn.) for Avon Cont'd 0 ' 13 26 41 14 5,844 9,281 15,125 165 11,852 Fails chrysotile Passes tremolite Fails chrysotile Passes tremolite Fails chrysotile Passes tremolite Fails chrysotile Passes tremolite Fails chrysotilePasses tremolite Dr. Tryggve Baak of United Sierra Spiked Italian Montana-! Montana-II 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 Richard E. Stevens of Ernest F. Fullam, Inc, for Whittaker C&iJ 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 & :remoli te Fails chrysotile & tremoli te Fails chrysotile & -renoli to Fails chrysotile & tr e m o l i te Fails chrysotile & remoli te Fails chrysotile & remoli te Spiked sample was not run. f 4- - 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 of McCrone Associates for Kolmar Italian Montana-I Montana-H Alabama Vermont *No. Carolina Spiked Sample 53 0 0 0 0 0 488 0 0. 0 0 0 0 16 Passes Passes Passes Passes Passes Passes 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 Labs. Mr. Salvatore DiBianca - The Mennen Company Liberty Mutual Insurance Co., Research Center - for Kolmar Laboratories 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 of problems encountered in the methodology. 1. The alph i refractive index of talc - one of the two indices exhibite 1 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-classiiication of such plates a; "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 imme-sion method for the determination ofrelative refractive index becomes unreliable when applied to extremely small (ca. 1 jim)par tides. This is due in part to the fact that particles around lj1711 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 ft 5- - 2. cause eye fatigue and resulting errors. Thus, a fine talc shard or plate on edge nay be easily mistaken for an asbestos fiber. This applies to both the chrysotile and amphibole 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 trenolite. 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. Refiner 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 unwarranted 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. ,-r *40' 6- - We estimate that a satisfactory method will take at least six months to a year to develop. We suggest a close liaison between FDA and industry in this all-out effort with updating reviews to take place as frequently as necessary. Review of Alternate Methods The CTFA 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 + 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. 4. 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 reliable for the detection of 1% tremolite (both fibrous and non-fibrous). 5. Differential Thermal Analysis - This procedure is capable of detecting chrysotile at the 1% level, however, it will not detect tremolite. 6. Scanning ElectronMicroscony - This procedure is not capable of identi fying asbestos. Even with energy dispersive analysis, completely satisfactory identification is not possible. 7. Transmission Electron Microscopy + Electron Diffraction - This appears to offer the best, most reliable method and is probably capable of detecting chrysotile and tremolite (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 procedure is miniscule. r 7- - Summary The CTFA Talc Subcommittee has completed its review of the Optical Microscopic Method for the Estimation of Chrysotile and Fibrous Tremolite in Talc, which appeared in the Federal Register, vol. 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. -i George W. Sandland Chairman CTFA Talc Subcommittee GWS:dd