EPA Clarifies Miscellaneous Materials Sampling - RePublished

Over the past several months in the asbestos refresher classes, we have been talking about the clarification letter that the Professional Abatement Contractors of New York (PACNY) sent to all asbestos contractors and consultants back in November 2007. This letter detailed clarification from the Environmental Protection Agency (EPA) under the Asbestos Hazard Emergency Response Act (AHERA) regulation to a question from Mr. Christopher Alonge of the New York State Department of Labor (NYSDOL) regarding the minimum number of samples that should be taken for miscellaneous materials. According to this clarification (follow the link above for the PACNY letter and clarification), the minimum number of samples that should be taken of miscellaneous materials (i.e., floor tiles, roofing, caulk, ceiling tiles) is two. The original AHERA section covering sampling of miscellaneous materials indicates that the word used in this part of the regulation is "samples" indicating more than one.

Realize this is only an issue if you took one sample of let's say floor tiles, and based on the result (remember floor tiles are analyzed utilizing the nonfriable organically bound material method of analysis, requiring final negative results to be analyzed by Transmission Electron Microscopy (TEM)) you said the floor tiles did not contain asbestos. The EPA clarification says that you needed another negative sample result to say the floor tiles did not contain asbestos. This issue obviously does not impact those of you who have been following our recommended procedure of taking at least three samples per homogeneous miscellaneous material. If you followed our recommendation you would have three negative results before declaring a miscellaneous material not asbestos-containing and would be in compliance with the clarification and the original regulation.

VAT Article from our 2007 Spring Newsletter.

A study published in the 2003 issue of “Applied Occupational and Environmental Hygiene” magazine titled “Asbestos Release During Removal of Resilient Floor Covering Materials” by Marion Glenn Williams, Jr. and Robert N. Crossman, Jr. of the University of Texas Health Center indicated that worker's exposure to asbestos during vinyl asbestos floor tile (VAT) removal may be under reported. Because we work in New York (NYS), we are very familiar with the limitations of polarized light microscopy (PLM) analysis on VATs or for that matter on any nonfriable organically bound (NOB) material. Under NYS Environmental Laboratory Accreditation Program (ELAP) requirements materials that are considered NOBs must go through a multiple step process for analysis. This process ends with analysis by Transmission Electron Microscopy (TEM) for samples that are negative for asbestos. This method is required for VATs because the type of asbestos typically used was Grade 7 asbestos known as Shorts & Floats. Grade 7 asbestos is no longer sold and was the cheapest asbestos material sold. The dimensions of this grade of asbestos was ultra-fine. With fiber dimensions approaching the less than 5 micron range. This study was done to determine if there was fiber release at the less than 5 micron level that was not being analyzed by the Phase Contrast Microscopy (PCM). PCM is used for air sample analysis and only analyzes greater than 5 micron fibers with a 3:1 or greater length to width ratio. The study found the following issues:

• When removing a non-asbestos sheet vinyl flooring with an asbestos felt backing the PCM method only reported 5-7% of the fibers counted by the TEM method.


• When removing an asbestos containing 12x12 VAT with asbestos containing mastic the PCM method only reported 2-2.5% of the fibers counted by TEM.


• When removing an asbestos 9x9 VAT with an asbestos mastic the PCM method reported 0-2.5% of the fibers counted by TEM.


• When removing mastic using a mastic remover (TEM levels were between 1.319-1.749 structures/cubic centimeter (s/cc)) versus amended water (TEM levels were between 0.094-0.184 s/cc).

This study shows that air sample results are significantly underreported using the PCM method of analysis. When performing VAT removals asbestos air monitors and project monitors should be using TEM analysis for clearance (at the very least) and they should be running a few TEM samples during the actual removal of the VATs. These would give us a better understanding of what is happening during VAT removals and ensure that the asbestos abatement was thoroughly completed.