Document 6bG1a4dXaRQZ5ZEO8NxK8eQ79

Minutes of the Meeting of the CTF/i Task Force or Methodology for the Detection of Asbestos in Tale held at the Johnson and Johnson Research Center s Tuesday, February I9, 19?** . Present vere the following : F. Robert Holle, Task Force Chairman Hal Stanley William c Eisenberg John W c Stuart Walter Luckewicz David H# Hamer John P. Schelz John M,. Faeq Cc Jc Panaentier lan K. Stewart Trygve Baak J. Pc SisakOj Jr. De Harris George Sandland Herb Conrad Affiliation Johnson and Johnson Pfizer FBk/BF/OS/M FDA Cosmetica Avon Products Johnson and Johnson Johnson and Johnson Colgate-Palmolive Co. Cyprus Industrial Minerals Walter C MeCrone Associates Cyprus Industrial MineraliColgate-Palmlive Co Cyprus Minerals Ccrp. Bristol % e r s Co. Johnson and Johnson OBJECTIVES Dr. Roll outlined the objectives of the task group to be: ''development of methods for the detection of fibrous amphibole and fibrous chrysotile in cosmetic grade talc.!? The methods must be applicable to finished products and must meet the following criteria: &} must be specific for detection of asbestos in talc and it* or a follow up method, mist discriminate between fibrous and nonfibrous forms of asbestos. b) must have definable detection limits. c) must be reproducible among different workers with different instruments. d) must result in a pass or fail on a talc. Before proceeding to a detailed discussion of methods submitted by participants, details of fc&lc inhalation studies were reported by Dr. Holie* -2 3MHAIATI0K STUDIES this work was done by Dr. F. Ik Fooiey in England to determine the amount of talc & baby might breathe during powdering The model system consisted of a doll which was sprinkled with talc to simulate powdering. The amo unt of airborne talc was measured using an M.R.E. personal air sampler which separates collected dust into respirable and non-respirable fractions. The point was made that 8 minutes of constant sprinkling were required to allow enough talc {microgram amounts) to be collected for measurement. These data vfcre then used to calculate the average number of talc particles a baby could be exposed to during a week. The calculation was outlined in detail and the data were compared with presently accepted industrial exposure limits for asbestos. It was concluded from these tests that even if talc were pure asbestos the levels of exposure of a b&by during normal powder ing are far below the accepted tolerance limits. The results and details of this experiment are being prepared for submission to the FDA. and CTFA. DEFIffXTXQN OF A FIBER Considerable time was devoted tc discussion of alternative definitions, of a fiber other than the 3:1 axial ratio as specified in the Federal Register which is felt to be unrealistic. It wag decided, however, to stay with this definition because of a lack of medical evidence correlating geo metric factors with potential health hazards. PARTICLE SIZE Hal Stanley reported that particle size studies of various talc samples submitted by participating CTFA members have been completed and that all are generally similar. These data will be submitted to the FDA to gether with tlie inhalation studies reported by J. and J, ANALYTICAL I4ETKOD6: Optical Microscopy; A promised method from Johns-Manville is under modification and was not submitted. Dispersion Staining - McCrone Associates Principles of the dispersion staining method were presented by David Hamer. From his experience the method was reported to be suitable for tresnolite down to levels of 0.1 percent but was not suitable for chrysotile. The principal reason is the size of chrysot le particles Which' are generally below the limits of resolution of the method . The minimum dimensions of visible tremoXite particles were estimated at 10 urn. x 2jm< One experiment was cited where up to chrysotile in a known spiked sample was missed. It was pointed out that in finished product talcs other added ingredients might interfere with the method. A combination of color and geometric factors Brest be considered when identifying a tremolite particle by this method. X-ray diffraction procedures for tremolite were submitted by representatives from Pfizer, JoIms.cn and Johnson, and Cyprus. Hal Stanley indicated that Pfizer's teclmique for tremolite, based on stop-scanning of the 110 reflection at IO.560 two-theta, lias a detection limit of 0*2$, There is general agreement that this detection limit can be reached by step-scanning precedences, but some disagreement as to the detection H m i t s achievable by normal scanning. Since the 10.5 6 two-theta peak is characteristic of amphiboles and the method is thus not specific for tremolite, the question of back-up methods was raised. Pfizer and Cyprus have used acid leachiiig followed by x-ray fluorescence for Ca as a back-up for tremolite. X-ray fluorescence is capable of detecting to limits of 0.1$. The possibility of interferences by Ca-containing substances, particularly in finished products, must be considered. Dispersion staining is also an alternate provided size criteria are met. Differential Thermal Analysia: Differential, thermal analysis as a method for serpentine minerals in talc was discussed by J. Schelz of Johnson and Johnson, This method was reported to detect 0.5 to 1.0$ ehrysotile which exhibits two thermal events, an endotherm at 650C and an exotherm at 830-8UOC, The method is specific for minerals of the serpentine class. The method does not depend on morphology and in the case of positive responses must be checked by microscopy. Walter Luckewicz of Avon confirmed J. & J, experience with BT&o Excellent agreement on samples exchanged between the two laboratories was reported. Some question as to the type of instrument used was raised, Avon uses DuPont and J. and J, uses Stone instrumentation. Hal Stanley cf Pfizer reported no success using Fisher equipment. Trygve Baak of Cyprus indicated reservations wit-' respect to reproducibility among different instruments and laboratories. X-Ray Fluorescence An x-ray fluorescence method capable of detecting 0.1$ tremolite based on C& analysis was reported by Cyprus. Acid leaching is used to remove acid soluble innerBering Ca-containing minerals. The question of in terferences by Ca compounds, especially in finished products, by flow agents or other additives, was raised. Positive responses must be followed up by another method such as fi.E.K. f dispersion staining or TEM with SAED. X-ray fluorescence is considered by Cyprus to be easier to quantify than X-ray diffraction. Atomic absorption can be used as an alternative for greater sensitivity. Electron Microscopy The Pfizer method for chrysotilc in talc utilizing TEM and SAED was presented in detail by Mr, Stanley* Ckrysotile is estimated easily at 0.1$ by weight. Fiber counts for ehrysotile in unknowns are compared with known mixtures similarly prepared. Identification, of fibers as chrysotile is made by SAED. -if. Cyprus techniques are similar hut include aluminum ahalowing to get & better idea of particle shape and as an internal standard for SAED. Levels of chrysotile are determined by count in comparison with standard. McCrone methods were discussed by Ian Stewart. They carry out diffraction studies at potentials of 150*200 Icvn utilizing talc itself as internal standard. Quantitation is b&sed on area percent determinations versus standards. The procedure requires several hours to carry out. It was pointed out that at 0.1$ chrysotile the fibers are readily apparent in every exposure arid can be readily estimated in a matter of minutes. SABD is necessary to identify fibers as chrysotile. Materials with simi lar morphology thus are eliminated from the count. McCrone's method is sensitive to well below the 0.1$ level for chrysotile. The method is suitable in situations where a great number of different talc specimens are to be studied. It was agreed that the Pfizer method would be used by the task group since it is the most accurately specified. Sample size will be at the operator's discretion but must be consistent. Aluminum shadowing will be included. The test will be pass or fail at the 0.1$ level. Infrared Spectroscopy An infrared, method, proposed by W. Luckewicz of Avon and based on an absorption at 765 cm-i, specific for tremolite, was discussed. Chlorite is an interference and must be eliminated by heating. Although the method was deemed useful for qualitative indication of the presence of tremolite, it was felt that additional, study of the quantitative aspects was needed before considering the procedure further. Summary The following methods will be used in round-robin studies: 1) X-ray diffraction for amphibole; if positive, to be followed up by SEM or dispersion staining to see if it is fibrous. Two positives and talc falls. 2) Differential thermal analysis for serpentine; if positive, to be followed up by TEM to see if it is chrysotile. Two positives and talc fails. 3) Transmission electron microscopy for chrysotile utilizing a spiked sample at the 0.1$ chrysotile level. If chrysotile is at the 0.1$ level or higher, talc fails. U) X-ray fluorescence for calcium in amphibole; if positive, to be followed up by SSM or dispersion staining to see if it is fabrous. Two positives and talc fails. J P S iK g Jc Pc Simko, Jr.