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Determination Detail

Control Number: A070006

Category: Asbestos

EPA Office: CAMPD

Date: 01/31/2007

Title: Rounding Reported Values

Recipient: Zlatic, Michael

Author: Alushin, Michael

Comments:

Subparts: Part 61, M Asbestos

References: Part 763, Subpart E, Appendix 

E, Section 1

61.141

Abstract:

Q: Could EPA clarify to the Saint Louis County Health Department in Missouri how 

best to interpret the following phrase in 40 CFR part 63, subpart E: "the value reported 

should be rounded to the nearest percent", in connection with point counting results to 

determine the percentage of asbestos as between 1.0 percent and 1.5 percent and 

defining Category I and Category II nonfriable asbestos-containing material (ACM)? 

A: EPA explains that when a bulk sample is analyzed using Polarized Light Microscopy, 

and further quantified using the point counting method/formula in 40 CFR Part 763, 

Subpart E, Appendix E, Section 1.7.2.4, sample results are allowed to be rounded to the 

nearest percent. EPA interprets the rounding of results using the formula in Section 

1.7.2.4 as, if the sample result yields a=4, “a” being the number of asbestos counts, the 
result is 1 percent, which does not meet the regulatory threshold of greater than 1 

percent. If the sample result yields a=5, the result is 1.25 percent asbestos, which may be 

rounded down to 1 percent, which is not greater than 1 percent and therefore not 

regulated. If the sample result yields a=6, the result is 1.5 percent asbestos, which would 

be rounded to 2 percent and therefore regulated. 

Letter:

January 31, 2007

Mr. Michael A. Zlatic, P.E.

Chief Environmental Engineer

Saint Louis County Health Department

Division of Environmental Protection

111 South Meramec Avenue

St. Louis, MO 63105

Dear Mr. Zlatic:

This responds to your letter of May 22, 2006 in which you request an EPA 

determination that addresses how the following sentence found in 40 CFR Part 763, 

Subpart E, Appendix E, section 1.7.2.4 should be implemented: "The value reported 

should be rounded to the nearest percent." You specifically ask how this sentence should 

be interpreted in connection with point counting results placing the percentage of 

asbestos as between 1.0% and 1.5% because the asbestos NESHAP specifically defines 

Category I and Category II nonfriable asbestos-containing material (ACM), in relevant 

part, as "containing more than 1 percent asbestos as determined using the methods 

specified in Appendix E, Subpart E, 40 CFR Part 763, section 1, Polarized Light 

Microscopy,: 

The sentence at issue first appeared in EPA's regulations in 1982. On May 27th of that 

year, EPA promulgated a Final Rule entitled Friable Asbestos-Containing Materials in 

Schools; Proposed Identification and Notification (47 FR 23360). In that final rule, EPA 

took a document originally entitled Interim Method for the Determination of 

Asbestiform Minerals in Bulk Insulation Samples, which had been referenced in EPA's 

proposed rule, and made it an appendix (specifically, Appendix A - Interim Method of 

the Determination of Asbestos in Bulk Insulation Samples) to the final regulatory text. 

Subsequently, when these regulations were amended in 1987, becoming EPA's current 

Asbestos-Containing Materials in Schools regulations (40 CFR Part 763, Subpart E), 

what was formerly Appendix A became, with some modification, Appendix E. The 

sentence at issue previously was found in Appendix A and is included in the current 

Appendix E, Subpart E. 

In responding to your inquiry, my staff researched previous Federal Register Notices, 
Agency guidance documents, and files from Docket # OPTS 61004B; TSH-FRL 2064-3 

(the docket for the Agency's 1982 Final Rule promulgating the Friable AsbestosContaining Materials in Schools regulations). They did not locate any specific reference 

in these materials discussing the sentence in Section 1.7.2.4. However, there are 

discussions in several documents in this docket regarding the variability of sample 

results analyzed by different laboratories. Based on results of sampling analysis by 

commercial and non-commercial laboratories, the Agency determined that the technical 

capability of the microscopist was crucial for proper sample analysis. In order to 

improve the sample analysis results by the microscopist, the Agency developed the 

previously mentioned document entitled Interim Method for the Determination of 

Asbestiform Minerals in Bulk Insulation Samples. In addition, the Agency worked with 

the Department of Commerce to develop a laboratory accreditation program to ensure 

accurate sample analysis. 

Based on our research, it is EPA's position that when a bulk sample is analyzed using 

Polarized Light Microscopy, and further quantified using the point counting method, 40 

CFR Part 763, Subpart E, Appendix E, section 1.7.2.4 (specifically, the sentence for 

which you are seeking clarification) allows for the rounding of such results to the nearest 

percent. For example, if the percent asbestos is calculated for a sample using the formula 

set forth in Section 1.7.2.4 - i.e., % asbestos = (a/n) 100%, where a=number of asbestos 

counts and n= number of nonempty points counted (400) -- and the sample result yields 

a=4, the result is 1% asbestos, which does not meet the greater than 1% asbestos 

regulatory threshold for ACM. If a sample result yields a=5, the result is 1.25% asbestos. 

In this case, section 1.7.2.4 of Appendix E allows rounding of the result to 1%. 

Accordingly, if rounded, this result does not meet the greater than 1% regulatory 

threshold for ACM. If the sample result yields a=6, the result is 1.5% asbestos. In 

rounding this sample result to the nearest percent, the result is 2% asbestos. This sample 

result is greater than 1% and therefore the tested material qualifies as ACM. 

The Office of Civil Enforcement, the Office of Air Quality Planning and Standards, the 

Office of Prevention, Pesticides and Toxic Substances and the Office of General 

Counsel have reviewed this determination.

Very truly yours,

Michael S. Alushin

Compliance Assessment and Media Programs Division Office of Compliance

cc: Tahani Rivers, OCE

Susan Fairchild, OAQPS

Chris Kaczmarek, OGC

Cindy Wheeler, OPPTS

Ellen Stough, OCEFT

Lynn Slugantz, Region 7