By December 29, 2023, the FDA is to issue a proposed rule establishing standardized talc testing methods and requiring testing of talc-containing products for the presence, or absence, of asbestos. The proposed rulemaking would be the first of its kind. Although the FDA has been monitoring for asbestos in talc-containing cosmetic products since 2017, no mandatory testing methods and no regulations pertaining to same have been put in place. Under MoCRA, this is about to change.
In 2018, the FDA established an interagency working group on asbestos in consumer products (IWGACP) to investigate and report on the scientific knowledge surrounding talc-containing products and the allegations of asbestos contamination. In 2022, the IWGACP issued a White Paper containing opinions and recommendations regarding talc-testing methods. While much remains to be seen, it is generally expected that the FDA’s proposed rulemaking on talc-testing methods will follow the IWGACP’s 2022 white paper’s recommendations.
The 2022 IWGACP White Paper makes the following recommendations for the industry:
- “Use both polarized light microscopy (PLM) and transmission electron microscopy (TEM) methods to identify/report, at minimum, the presence of asbestos, other amphibole minerals, and talc particles exhibiting non-platy morphology.
- Tabulate, at minimum, all amphibole and chrysotile particles having a length ≥ 0.5 micrometer (µm) (500 nanometer (nm)) and a ratio of length to width, i.e., aspect ratio (AR), ≥ 3:1 in talc-containing cosmetic products and talc intended for use in cosmetics, and avoid categorizing such particles as non-asbestiform when there is ambiguity as to habit of growth.
- Scanning electron microscopy (SEM) can be used as a complementary method to TEM, but has certain limitations at this time.
- TEM results should be reported by tabulating each particle to facilitate an estimate of the number of particles per unit mass of sample analyzed (i.e., particles/gram of talc, particles/gram cosmetic product), rather than as weight percent.
- An adequate number of TEM images that show the morphology of representative particles in each category described in #1 and an adequate number of energy dispersive spectroscopy (EDS) spectra and selected area electron diffraction analysis (SAED) patterns to support mineral identification should be provided.
- Samples should be prepared to mitigate interference from the sample matrix using techniques similar to those used for the testing of bulk materials for asbestos.
- Content and format of analytical reports should facilitate consistent and comprehensive reporting of particles (as described in #1 and 2), in conjunction with adequate documentation of findings.
- Policies and procedures covering rigorous training, quality assurance, and quality control should accompany the implementation of these methods to maintain intra- and interlaboratory consistency and to ensure laboratories are qualified and their qualifications are reviewed regularly.”
The Available Talc Testing and Sample Preparation Methods
The methods for talc testing and sample preparation that were often used included J4-01 and USP NF which were introduced in 1976 and used by the former Cosmetic, Toiletry, and Fragrance Association (CTFA). These methods rely on the use of x-ray diffraction (XRD) or infrared (IR) spectroscopy followed by polarized light microscopy (PLM) only if XRD or IR is positive for amphibole or serpentine minerals in talc. J4-01 also allows for an alternative screening step by infrared spectroscopy.
Both J4-01 and USP NF continue to be used. There are additional methods for testing and sample preparation, which are not limited to talc and test for asbestos under different circumstances, e.g. asbestos in bulk samples, fibers on surfaces, airborne asbestos fibers. Some of these are the following:
- Heavy Liquid Separation (HLS) – This sample preparation method was developed by the Colorado School of Mines and is based on the principle that material whose specific gravity is less than the liquid’s will float, and material with greater gravity will sink. HLS involves separation, or floating, of talc from any other allegedly present particles.
- ISO 10312 – Employed in other exposure scenarios, this method uses TEM for the determination of airborne asbestos fibers in a wide range of ambient air situations, including the interior atmospheres of buildings, and for a detailed evaluation for asbestos structures in any atmosphere. “This method cannot discriminate between individual fibers of asbestos and elongate fragments (cleavage fragments and acicular particles) from non-asbestos analogues of the same amphibole material.”
- ISO 22262-2 – This method uses a quantitative determination of asbestos by using gravimetric microscopical method. Its primary use is for samples in which asbestos has been identified at estimated mass fractions lower than approximately 5% by weight. It is not the intent of ISO 22262 to provide instruction in the fundamental microscopical and analytical techniques.
- ASTM D6480 – This method’s primary use is for testing of surfaces for asbestos. This method takes an index of the concentration of asbestos structures per unit from the area sampled. The concentration is derived from the quantitative measure of the number of asbestos structures detected during analysis. This method does not provide any direct data to determine human exposures, compliance with regulations and statutes, or safety and habitability of buildings. The indirect preparation method used on the sample under this method may create large asbestos surface loading results.
- ASTN D5755 – This method uses microvacuum sampling of non-airborne dust for asbestos. It provides an index of the surface loading of asbestos structures in the dust per unit area analyzed as derived from a quantitative TEM analysis. Similarly, to ASTM D6480, this method does not provide any direct data to determine human exposures, compliance with regulations and statutes, or safety and habitability of buildings. The indirect preparation method used on the sample under this method may create large asbestos surface loading results. In addition, this standard has been withdrawn in 2023.
- NIOSH 7400 – This method employs phase-contrast microscopy (PCM) to measure airborne asbestos fibers, often to determine compliance with OSHA regulations. PCM cannot observe fibers under a certain size and cannot distinguish asbestos from non-asbestos fibers.
- NIOSH 7402 – This method, an adjunct to NIOSH 7400, employs TEM to determine the percentage of asbestos fibers as a fraction of all fibers found by PCM under NIOSH 7400. For practical purposes, compliance with OSHA regulations is usually determined without resort to NIOSH 7402 if total fibers found by PCM under NIOSH 7400 are below the OSHA standard.
- EPA 600/R-93/116 – This method uses polarized light microscopy (PLM) to provide a visual estimation of asbestos in bulk building materials. Although the EPA expresses that it works well for most sample types, estimation may not be accurate for low concentration asbestos and for fibers below certain dimensions.
Although the FDA is expected to follow the White Paper’s recommendations in its 2023 proposed rulemaking under MoCRA, much remains to be seen as many other talc testing options are also under consideration. Stay tuned for the Product Perspective’s updates on the FDA’s rulemaking as it comes out in December 2023.