Two different methods, three different variations, four different sources: what bulk asbestos PLM method is your laboratory using? Part 1

Our plain-English summary of Two different methods, three different variations, four different sources: what bulk asbestos PLM method is your laboratory using? Part 1, by D.B. McGrath, D.R. Van Orden, R.M. Howard, et al (Journal of Occupational and Environmental Hygiene, 2010).

The study

• Authors: D.B. McGrath, D.R. Van Orden, R.M. Howard, P. Guerrero, S.C. Davis
• Journal: Journal of Occupational and Environmental Hygiene
• Published: 2010;7(8):D53-6
• Cited by: 1 article, as counted by NIH iCite
• Read it: PubMed · Publisher

In plain English

This was a column, Part 1 of a two-part series, not a study of people. The authors reviewed the federal regulatory history of polarized light microscopy methods for measuring asbestos in bulk building materials. Under these rules, materials with more than 1% asbestos by a particular method count as asbestos-containing. The authors reported that the only legally binding method was the Interim Method. It was adopted in 1982 under the TSCA Asbestos in Schools Rule, moved to AHERA in 1987, and incorporated into the asbestos NESHAP in 1990. In their account, this method requires a representative sample and a volumetric average of separately analyzed layers for the whole sample, with three fallback procedures when that averaging cannot be performed. A 1982 correction allowed an equivalent estimation method instead of a 400-point count, but a December 1982 EPA publication required point counting only. A 1993 EPA method (EPA/600/R-93/116) rejected layer averaging, so one layer above 1% could put a whole material over the threshold. The authors concluded that the 1993 method was never promulgated through rulemaking and remains non-binding for AHERA and NESHAP compliance.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Commentary column reviewing regulatory history (Part 1 of a two-part series); not a study of people or exposure
• Who was studied: No people were studied; the column examined U.S. federal asbestos regulations and EPA test-method documents
• Exposure: Bulk asbestos polarized light microscopy (PLM) test methods used to decide whether a material contains more than 1% asbestos
• Main results:
  • The authors stated that only one bulk asbestos analytical method, the Interim Method, has been made legally binding by regulation
  • The 1982 TSCA method requires a representative sample containing all layers of the material
  • The binding methods require separate analysis of layers and their mathematical combination as a volumetric average to estimate the asbestos content of the entire sample
  • When layers cannot be separated or discerned and volumetric averaging cannot be performed, the method allows three secondary or fallback procedures
  • A September 1982 correction allowed PLM quantitation by a 400-point count or an equivalent estimation method
  • The December 1982 EPA-600/M4-82-020 version of the Interim Method requires 400-point counting only
  • The authors stated that the binding test methods under TSCA (1982), AHERA (1987) and the asbestos NESHAP (1990) are identical
  • The 1993 EPA/600/R-93/116 method rejected the multi-layered averaging required by the binding method
  • The 1993 method has never been promulgated through rulemaking and, in the authors' view, remains non-binding for AHERA and NESHAP compliance
• The authors' conclusion: The authors concluded that if the EPA wants to use another test method for compliance and enforcement, it must first promulgate that method through rulemaking with public participation and judicial review, and that it has not done so

Related studies

• Analytical performance issues. Two different methods, three different variations, four different sources: what bulk asbestos PLM method is your laboratory using? Part 2 — D.B. McGrath, D.R. Van Orden, et al. (2010)
• An air quality data analysis system for interrelating effects, standards, and needed source reductions: Part 13--Applying the EPA Proposed Guidelines for Carcinogen Risk Assessment to a set of asbestos lung cancer mortality data — R.I. Larsen (2003)
• Risk assessment of asbestos containing materials in a deteriorated dwelling area using four different methods — Y.L. Zhang, H.S. Byeon, et al. (2021)
• Development of a method for the determination of low contents of asbestos fibres in bulk material — T. Schneider, L.S. Davies, et al. (1998)
• The four most pernicious myths in asbestos litigation: Part I: safe chrysotile and idiopathic mesothelioma — C. Meisenkothen (2014)
• The four most pernicious myths in asbestos litigation: Part II: safe thresholds for exposure and Tyndall lighting as junk science — C. Meisenkothen (2014)

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