The United States Food and Drug Administration (US FDA) formed the Interagency Working Group on Asbestos in Consumer Products (IWGACP). They have released their Executive Summary Preliminary Recommendations on Testing Methods for Asbestos in Talc and Consumer Products Containing Talc (January 6, 2020).
A public hearing will be held on February 4, 2020 to discuss these recommendations.
The FDA paper presents the following recommendations which appear to be of most interest to the NOA-EMP community (however, please download and read the entire Executive Summary for further details):
- Transmission electron microscopy (TEM) should be used for asbestos-testing of talc, even if the findings of PLM are negative.
- To date, counting rules have not specifically considered biological activity, overt toxicity, or epidemiology of the kinds of chrysotile and amphibole particles being detected and counted. That is, all mineral particles meeting specified criteria for mineral type and dimensions are expected to be reported and counted.
Published methods for analysis of bulk materials were not intended to determine the presence of asbestos in products at less than 1% concentration.
- IWGCAP agrees with the recommendations and rationale provided in the peer reviewed NIOSH Bulletin 62 regarding adopting the term “elongate mineral particle” or “EMP” that is defined as “any mineral particle with a minimum aspect ratio of 3:1” Thus, and EMP encompasses both asbestiform and non-asbestiform particles that have dimensions that enable them to be respirable.
For talc and talc-containing products:
- Covered minerals include chrysotile (but not other serpentine minerals) and members of the amphibole group (inclusive; not restricted to the five amphiboles used commercially).
- Countable EMPs have an aspect ratio of >= 3:1 and a length of >0.5 um using the most inclusive criteria for length and AR from among the “asbestos” counting rules in established testing protocols.
IWGACP recommends (among other items):
- Adoption of the term EMP as “any mineral particle with a minimum aspect ratio of 3:1”
- Testing laboratories report all EMPs having length >= 0.5 um (500 nm).
- That test methods specify reportable EMPs identified as amphibole or chrysotile particles as covered minerals.
- Test methods require the counting and reporting of covered EMPs as a function of sample mass.
- Use of TEM at nominally 20,000x magnification, in addition to PLM, to resolve the issues of sensitivity that cause reporting of false negatives for covered EMPs.
- That “mass percent” a unit that is frequently used to express content of asbestos in commercial bulk materials is not appropriate for measurement of EMPs in talc and consumer products containing talc because weight percent does not correlate with the number of fibers, and one large fiber could dominate the mass percent value.
- IWGACP recommends reporting and counting all EMPs of covered minerals under a single classification