Document 71rjome16pVv66azGXKOkK8eV

Minutes of the Meeting of the CTFA Task Force on Methodology for the Detection of Asbestos in Talc held at the Johnson and Johnson Research Center, Tuesday, February 19, 197^* Present were the following: F. Robert Rolle, Task Force Chairman Hal Stanley William V. Eisenberg John W. Stuart Walter Luckewicz David H. Hamer John P. Sehelz John Mr.Faeq C e J. Parmentier Jan M. Btevsrt ' - - Trygve Beak J,, P. Simko, Jr Bo Harria ' George Sandland Herb Conrad Affiliation Johnson and Johnson Pfizer FM/BF/03/DM FEA Cosmetics Avon Products Johnson and Johnson Johnson and Johnson Colgate-Palmolive Co. Cyprus Industrial Minerals Walter C. McCrone Associates Cyprus Industrial Minerals Colgate-Palmolive Co. Cyprus Minerals Corp. Bristol ifyQTB Co. Johnson and Johnson OBJECTIVES Dr. Rolle 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. V '" The methods must be applicable to finished products and must meet the following criteria: a) must be specific for detection of asbestos in talc and it, or a follow' up method, smgt discriminate between fibrous and non-fibrous forms of asbestos. b) must have definable detection limits. c) must be reproducible among different workers with different instruisents . d) must result in a pass or fail on a talc. Before proceeding to a detailed discussion of methods submitted by participants, detail of talc inhalation studies were reported by Dr. Rolle. INHALATION STUDIES Thls work m s done by Dr. F. D. Pooley in England to determine the amount of talc a baby might breathe during powdering. The model system consisted of a doll which m s sprinkled vith talc to simulate pondering. The amount of airborne talc was measured using an M.R.E. personal air eaapler which separates collected dust into respirable and non-respirable fractions. The point m s made that 8 minutes of constant sprinkling were required to allow enough talc (microgrsm amounts) to be collected for measurement. These data, were 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 baby 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. HgrmrraE of a fiebr Considerable time was devoted to 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 was 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 tbs inhalation studies reported by J. and J. mMJTFIC&L METHODS; Optical Microscopy^ promised method from Johns-ManviHe is under modification and was not submitted. Dispersion Staining ^inciples of the dispersion staining method were presented by David Hffiaer. Press hie experience the method was reported to be suitable for tremolite down to levels of 0.1 percent but was not suitable for chrysotiie. The principal reason is the size of chrysotlle particles milch* are generally below the limits of resolution of the method . The minimum dimensions of visible tremolite particles were estimated at 10 p m x 2 ^jom. One experiment was cited where up to 7$ chryaotile in a known spiked cample was missed. It wag pointed out that in finished product talcs other added ingredients might interfere with the method. A combination of color and geometric factors must be considered when identifying a tremolite particle by this method. X-ray Diffraction: X-ray diffraction procedures for tremolite vers submitted by representatives from Pfizer, Johnson and Johnson, and Cyprus. Hal Stanley indicated that Pfizer's technique far tremolite, based on step-scanning of the 110 reflection at IO.560 two-theta, has a detection limit^cf CL2$. There is general agreement that thin detectiorTOffiSTT"can'^be 'reached by step-scanning procedures, but some disagreement as to the detect!on^TmlTa achievable By normal scanning. Since the 10 .56 two-theta peak is characteristic of amphiboles and the method is thus not specific for tremolite, the question of back-up methods was raigefi. Pfizer and Cyprus have used acid leaching followed by x-ray fluorescence for Ca as a back-up for tremolite. X-ray fluorescence is capable of detecting tc limits of 0.1$. The possibility of interferences by Ca- containing grubstances, particularly in finished productsp must be considered. Dispersion staining is also ar elternate provided size criteria are met. Differential Thermal Analysis: Differential thermal analysis as a method for serpentine minerals in talc was discussed by J. Behels of Johnson and Johnson. This method m s reported to detect 0.5 to 1.C$ chrysotile which exhibits two thermal events, an endotherm at 6 5 ^ 0 end an exotherm at o30-oa0C. 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 Luckevicz cf Avon confirmed J. & J. experience with BT&. Excellent agreement on samples exchanged between the two laboratories was reported. Some question as to the type of instrument used was raised. Avon DuPont and J. and J. uses Stone instrumentation. Hal Stanley of Pfizer reported no success using Fisher equipment. Trygve Baak of Cyprus indicated reservations with respect to reproducibility among different instruments and laboratories. X-Ray Fluorescence An x-ray fluorescence method capable of detecting 0.1$ tremolite based on Ca analysis vas reported by Cyprus. Acid leaching is used to remove acid soluble interfering Ca-containing minerals. The question of in terferences by Ca compounds, especially in finished products, by flowagents or other additives, was raised. Positive responses must be followed up by another method such as S.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 Tie Pfizer method for chrysotile in talc utilizing TEM and SAED was presented in detail by Mr. Stanley. Chrysotile is estimated easily at 0.1$ by weight. Fiber counts for. chrysotile in unknowns are compared with known mixtures similarly prepared. Identification of fibers as chrysotile is made by SAED. -k- C vp rus techniques are similar but include aluminum shadowing to get a better idea of particle shape and as an internal standard for SAED. Levels of chrysotile are determined by count, in comparison with standard. methods were discussed by &/& They carry out diffraction studies at potentials of 150-200 kv. utilizing talc itself as internal standard. Quantitation is based on area percent determinations versus standards. The procedure requires several bonrs to carry out. It was pointed out that at 0.1$ chrysotile the fibers are readily apparent in every exposure and 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. MeCrone'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. Luckewiez of Avon and based on an absorption at 7b5 em-1, specific for tremolite, was discussed. Chlorite is an interference and must be eliminated by heating. Although the method wag 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. Sussaary The following methods will he used in rou&d-robin studies: l) 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 fails. 2) Differential thermal analysis for serpentine; if positive, to be followed up by TEK 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. k ) X-ray fluorescence for calcium in asaphibole; if positive, to be followed up by SIM or dispersion staining to see if it is fabrous. Two positives and talc fails. JPS:mg J . P. Slreko, J r. V*