Document 3J2V24MYGEz1n9L9q6reY2e7E

FILE NAME Talc TALC DATE 1976 Mar DOC TALC155 DOCUMENT DESCRIPTION Memorandum of Meeting between Environmental Sciences Labs Staff RE Analyzing Asbestos Minerals in Talc RLY MEMORANDUM OF MEETINGMEETING 1976 at Environmental Sciences Laboratory Laboratory Mount Sinai School of Medicine City University of New York : BETWEEN SUBJECT Members of the Staff of Environmental Sciences Laboratories Arthur M. Langer Arthur N. Rohl Division of Cosmetics Technology FDA Clifton H. Wilson Ronald L. Yates Analytical Methodology for the Detection and Determination of Asbestos Minerals in Talc Upon arriving at the greeted by Dr. Rohl as soon as possible laboratory Dr. He stated that Mr. Yates gave Wilson and Mr. Yates were Dr. Langer would be present Dr. Rohl the cosmetic talc samples that Dr. Langer had agreed to analyze In turn we requested and received subsamples of the 10 cosmetic talcs in which Dr. Langer reported the presence of tremolite and anthophyllite These are Body 1 hae ponder Cashmere . Rosemary talc 3 Brut for Men Faberge Air Spun Face Powder Coty Baby talc Bauer and Black Black Label Yardley After Shave talc English Leather 8 ZBT Baby Powder Invisible talc Yardley Shave talc Mennen Dr. Langer arrived approximately 30 minutes after our arrival Mr. Yates presented him with the covering letter concerning the cosmetic talc samples DCST had provided for his analysis Dr. Langer Dr. Rohl following topics Dr. Wilson and Mr. Yates then discussed the Sample Preparation and Instrumental Conditions for Analysis of Talc by ray Diffraction - Dr. Langer stated that he did not believe it possible to prepare a sample for ray analysis that had a completely random orientation of the chrystal lattice He did not think that random distribution was important if sample preparation techniques were consistent Mr. Yates informed Dr. Langer that in the proposed CTFA method preferred orientation was inevitable because the sample was pressed hydraulically Dr. Langer thought the technique acceptable if consistent results were obtained Dr. Langer demonstrated the sample preparation technique used by his group After preparation was completed sample was scanned in increments of 0.02 0.02 through at each the area of interest until step Divergence slits of a count of 2000 was obtained 4 are frequently although not always used When Dr. Wilson asked Dr. Langer about the possibility of scatter and high background from the use of a 4 slit Dr. Langer stated that the use of a smaller slit would probably increase resolution and sensitivity He was somewhat noncommittal about the effect of a 4 slit on quantitative results Dr. Langer summed up by stating that if good standards are used and sample preparation is reproducible and consistent He reliable analytical results should be obtained Tremolite - Dr. Langer stated that tremolite and talc fibers can be easily differentiated using light microscopy The cleavage of tremolite and anthophyllite is 90 to the crystal axis while talc has an angular cleavage There is also a difference in refractive index Tremolite and anthophyllite can be differentiated by the difference in aspect ratio DI aspect typically 40 1 Talc fibers appeared to have a cleavage of approximately 60 Dr. Wilson asked Dr. Langer to examine a sample of tremolite he had brought along Dr. Wilson said that he had been using the sample as a standard but that ray analysis indicated impurities Dr. Langer examined the sample using HHS00000019 optical microscopy He stated it contained anthophyllite tremo- lite quartz and talc ray analysis of the sample indicated talc anthophyllite and tremolite He had a microscopist on his staff examine the sample using optical microscopy His analysis confirmed Dr. Langer's results in London considered He gave Dr. Wilson the address of a firm that could provide samples to be the purest available the Cape Asbestos Co. of Korean tremolite Dr. Langer said detectability levels for tremolite was approximately 0.1 by ray diffractometry If tremolite particles had aspect ratios of 3 to 1 or greater they were considered fibrous Chrysotile - According to Dr. Rohl detectability by ray fluorescence was 0.25 depending on size and crystallinity Dr. Rohl had some photographs taken of chrysotile fibers fibrils using transmission electron microscopy TEM Photograph showed fibers containing several fibrils and individual fibrils Aspect ratios were extremely high When examining talcs by TEM a count of grid square is considered background In two of the 19 commercial cosmetic talcs examined fiber counts of approximately 24 fibrils square were obtained Dr. Langer considered this to be quite low and probably not hazardous In general he did not think that chrysotile was a real problem as far as cosmetic talcs were concerned He refuted claims made by some that asbestos fibers were not present in the environment due to use of asbestos brake shoes in automobiles He stated that they have analyzed dust obtained from auto brake drums and have identified asbestos fibers Nickel - In reference to the high amounts of nickel present in some talcs Dr. Langer said that nickel replaces magnesium in the talc lattice and becomes a nickel hydroxy silicate complex He is not convinced that nickel is harmless in this form because of its similarity to nickel hydroxide which has been found to cause rhabdomyosarcomas in rats when injected Transmission Electron Microscopy TEM Dr. Rohl demonstrated the use of TEM for the analysis of talcs using previously prepared samples Using a prepared sample of unknown identity he pointed out structures typical of talc and tremolite He also demonstrated that use of selected area diffraction The crystal to be examined is centered on the screen and the beam is then passed through the area of the crystal desired on the screen as a series of The dots diffraction pattern is displayed quite similar to a Laue photograph The pattern can then be compared with those of standards for characterization HHS00000020 In general the Environmental Sciences Laboratory is well equipped for mineralogical analysis having two transmission electron microscopes two scanning electron microscopes an ray diffractometer analyzer an optical microscoapned a differential thermal ; A Rescald& Yate oe Yate Ronald L. Yates HHS00000021