P.1 

OAR Box 1338 

Prepped by Ollie Stewart 

Document Number: 

49) V-C-1 

Docket Number: 

A-89-11 

Printed 6/17/2008 1:48:07 PM Sheet 49 of 105 
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/4-89-/I 

* y>.«t V-c-/ 

'cJJJ-LLiXf^ 

IM MAR-7 1991 Ml 

I EP/~jL[:ri'r~~-;i 

SUMMARY OF COMMENTS AND 

RESPONSES FOR METHODS 23 AND 26 
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TABLE OF CONTENTS 

Page 

Chapter 1. Introduction^ 1 

4 

Chapter 2. Summary of Changes Since Proposal 2 

Chapter 3. Summary of Comments and Responses 3 

List of Commenters 
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/• 

LIST OF ACRONYMS USED 

CDD - Chlorinated Dibenzo-p-Dioxin 

CDF - Chlorinated Dibenzo-p-Dioxin 

4 

CFR - Code of Federal Regulations 

EPA - Environmental Protection Agency 

GC - Gas Chromatography 

HCl - Hydrochloric Acid 

HpCDD - Heptachloro-Dibenzo-p-Dioxin 

HxCDD - Hexachloro-Dibenzo-p-Dioxin 

MWC - Municipal Waste Combustor 

MS - Mass Spectrometry 

NPRM - Notice of Proposed Rulemaking 

NSPS - New Source Performance Standard 

OCDD - Octachlorinated Dibenzo-p-Dioxin 

OCDF - Octachlorinated Dibenzofuran 

PCDD - Polychlorinated Dibenzo-p-Dioxin 

PCDF - Polychlorinated Dibenzofuran 

PeCDF - Pentachloro-Dibenzo-p-Dioxin 

QA - Quality Assurance 

QC - Quality Control 

TCDD - Tetrachloro-Dibenzo-p-Dioxin 

TCDF - Tetrachloro-Dibenzofuran 

TMQL - Theoretical Minimum Quantification Limit 

n 
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Chapter 1 

INTRODUCTION 

On December 20, 1S89, the U.S. EPA published in the Federal Register (54 

4 

FR 52190) Method 23, "Determination of Polychlorinated Dibenzo-p-Dioxins and 

Polychlorinated Dibenzofurans from Stationary Sources" and Method 26, 

"Determination of Hydrogen Chloride Emissions from Stationary Sources." These 

methods were proposed under the authority of Sections 101, 111, 114, 116, and 

301 of the Clean Air Act, as amended. 

Public comments were solicited at the time of proposal. To provide 

interested persons the opportunity of oral presentation of data, views, or 

arguments concerning the proposed test methods, a public hearing was scheduled 

at 10:00 a.m. on February 7, 1990" at the Research Triangle Park, North Carolina, 

but no one requested a hearing. The public comment period was from December 20, 

1989 to March 5, 1990. 

Twelve comment letters were received concerning issues relative to the 

proposed test methods. A detailed discussion of these comments have been 

carefully considered, and necessary changes have been made in the proposed 

methods. 
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Chapter 2 

SUMMARY OF CHANGES SINCE PROPOSAL 

METHOD 23 

1. The cleanup procedure for the sample train has been changed to require 

more thorough rinsing. 

2. The option of wrapping filter samples in aliuminum foil after collection 

has been deleted. 

3. Method 23 has been changed to give the tester the option to choose gas 

chromatographic column systems other than the recommended system, provided 

that the necessary resolution can be acheived. 

4. The concentrations of the calibration standards in Table 2 have been 

lowered. 

5. The method now requires the analyst to include a lock mass and a check 

channel for the mass spectrometer during sample analysis. 

METHOD 26 

1. The option of using an in-stack filter has been deleted. A heated 

out-of-stack filter is now required. 

2. The requirement for facing the sampling nozzle away from the direction of 

the stack gas flow has been deleted. 
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Chapter 3 

SUMMARY OF PUBLIC COMMENTS AND RESPONSES 

4 

Method 23 

Commenter IV-D-01 

1.1 Comment: We are dismayed that there are so many minor differences 

between this method and the sampling and analytical methods for PCDDs and 

PCDFs found in EPA publication SW-846 "Test Methods for Evaluating Solid 

Waste." The proliferation of minor differences between methods used for the 

same contaminants at different sources will only lead to confusion in the 

field and in the laboratory. 

Response: There is no procedure in SW-846 for measuring PCDD's and 

PCDF's by high resolution mass spectrometry, although there is a method using 

low resolution mass spectrometry. Any differences in the procedures are 

generally a result of the different types of samples or sources to which the 

methods will be applied. We have attempted to eliminate all unnecessary 

differences. 

1.2 Comment: We feel that the addition of surrogate standards to the 

XAD-2 resin is of little value to the quality control program. The standards 

are added in a single dose, before sampling and are subject to the entire 

sampling run, while any PCDDs or PCDFs in the emissions are added over the 

entire sampling period. Since the migration of the PCDDs/PCDFs along the 

resin cartridge would start when the sampling started, the surrogates would 

break through before the native PCDDs/PCDFs. It would be possible to have a 

50 percent loss of surrogates without having a 50 percent loss of natives. It 
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would also be incorrect to apply the collection efficiency correction of the 

resin to the PCDDs/PCDFs found in the filter catch and the rinse solvents. 

Any PCDOs/PCDFs lost from the glassware or filter would be collected by the 

resin. Since all portions of the train are extracted and combined into one 

extract, it is not possible to apply a correction to just the resin results. 

Section 7.3 of the method does not define what constitutes "isolated surrogate 

compounds" and it is therefore not clear when the correction factor should be 

applied^ 

Response: In our own testing program, we consistently showed surrogate 

recoveries in the allowable range of 70-130 percent. Although it is true that 

this might test overestimate the effect of breakthrough, we believe that any 

well controlled sampling train will show recoveries in the acceptable range. 

If we eliminated this quality control check, we would not have any means to 

determine if sample breakthrough had occurred. While it is not strictly 

accurate to apply a collection efficiency correction to the whole sample based 

solely on the recovery of material from the adsorbent cartridge, this is 

offered only as an option and is not a requirement. Because the effect of 

this correction would be to overestimate the PCDD's/PCDF's, any source that 

choose this alternative and still complied with the regulation would be spared 

the cost of a retest without affecting its compliance status. Thus we do not 

plan to change this quality control requirement. 

1.3 Comment: The use of methylene chloride as a rinse solvent in the 

field (Section 4.2.4) should be dropped form the method. Methylene chloride 

is a suspected carcinogen and its use in the field where proper ventilation is 

not always possible, is hazardous to the members of the sampling team. 

Whatever small gains in recovery that may be made by using methylene chloride 
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in place of a less toxic solvent such as hexane or toluene, would be lost in 

an analysis where an acceptable internal standard recovery is 40-130 percent 

and good precision would be ±50 percent on duplicate samples. 

Response: We are in the process of investigating toluene as a possible 

alternative solvent to methylene chloride, but until we can determine that it 

does not affect the amount of PCDD's/PCDF's recovered from the sampling train 

we cannot substitute for the solvent that was used during the collection of 

the data to support the regulation. 

1.4 Comment: The method should also require a field blank train that 

is treated identical to the sample trains and analyzed along with the samples. 

Response: Although it would be a good idea for the tester to do this as 

part of an internal quality assurance program, we do not believe it is 

necessary to require this as part of the compliance test method. Field blank 

trains would only demonstrate that a positive bias might have existed during 

the sample collection. Because a positive bias in the final result would be a 

disadvantage to the source there is an inherent incentive to prevent this 

occurrence. 

1.5 Comment: Finally, there are apparently two typographical errors in 

Table 1. The last internal standard listed should be

 13C12-l,2,3,4,6,7,8-HpCDF. 

The first surrogate standard should be

 37Cl4-2,3,7,8-TCDD. 

Response: There were two typographical errors. Both of these have been 

corrected. 

Commenter IV-D-03 

2.1 Comment: Another problem associated with using dioxin/furan 

emissions and Method 23 as the measure of organic emissions not addressed in 

the NPRM is the procedure itself. There are very few stack sampling 
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organizations in the world that have experience with the method. Only a 

handful of laboratories have the GC/MS equipment necessary to perform the 

method. The biggest problem, however, is the availability of standards 

(laboratory and field).^ How does EPA plan to address this issue? With a 

4 

requirement for annual dioxin/furan testing on all new and existing MWC s (see 

comment concerning frequency of testing), there will be major delays in 

securing sampling and analytical contractors. How will this known problem be 

dealt with from a compliance standpoint? 

Response: We believe that the number of tests required immediately 

after promulgation of the regulation will not exceed the capabilities of the 

available sampling and analytical laboratories and that there will be an 

adequate supply of labeled standards and audit samples. The full effect of 

the testing requirements for the'new and existing sources will not be felt for 

about five years. We believe that this is adequate time to allow for the 

necessary expansion of testing capabilities. 

2.2 Comment: If, however, EPA continues to advocate the currently 

proposed Method 23, EPA should at least allow functionally equivalent methods 

and/or equipment to be used where comparable results for total CDD/CDF levels 

can be obtained. EPA should review methods available from the California DOHS 

and ARB and the Ontario MOE at a minimum before settling on the current Method 

23. For example, the laboratory that developed the proposed Method 23 

(currently existing as Method 8290 in EPA SW-846) uses the DB-5 column and the 

DB-225 column for quantification of all isomers including 2, 3, 7, 8-TCDF, 

while Method 23 calls for the DB-5 and the SP-2331 columns. 

Response: Testers always have the option of requesting alternative 

methods, but this is not the appropriate avenue to submit such requests. 
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Requests for alternative methods should be submitted after the method is 

promulgated. The request should be in writing and should contain any 

supporting data. 

EPA reviewed othei^methods before beginning its program to collect data 

4 

in support of a regulation for MWCs. The proposed Method 23 reflects the 

procedure used to colle'ct this supporting data as required by law. 

The method has been revised to allow alternative gas chromatography 

column systems provided that the user can demonstrate through calibration and 

performance checks that the columns will provide the necessary isomer 

separation. 

2.3 Comment: In Section 1, a new Section 1.3 should be added to remind 

the users that this sampling method eliminates any possibility of obtaining a 

vapor/particle distribution of total CD/CDF or any of the isomers or 

congeners. 

Response: Section 1.2 has been revised to make it clear that Method 23 

cannot determine a vapor/particle distribution of PCDD's and PCDF's. 

2.4 Comment: In Section 5.1.1, it appears that the reference to "the 

concentrate from Section 5.1.2" is really from Section 5.1.3. 

Response: This is correct. Section 5.1.1 has been revised accordingly. 

2.5 Comment: In Section 8.3, Audit Sample Availability, there is 

concern that even if requests are made in a timely manner EPA may not be able 

to keep up with the demand to provide these and thus critical financial 

deadlines could be jeopardized based on delays even beyond the control of EPA. 

We request that EPA add flexibility to the audit procedure to prevent problems 

before the method is finalized. 
Response: We believe that the number of tests required immediately 

after promulgation of the regulation will not exceed our ability to provide 

the necessary audit samples. 

2.6 Comment: Infection 9, EPA should add a section to codify its 

current practice offonlyllistingjnondetected isomers or congeners and not 

including them in the calculation of total CDD/CDF. If nondetects are to be 

counted as the detection limit, a rethinking of appropriate emission limit is 

in order. 

Response: Section 9 has been revised to clarify that it is EPA's intent 

to count "nondetected" results as zeroes. 

2.7 Comment: The final quality assurance rinse uses toluene. EPA 

states that it will continue to review toluene field rinse quality assurance 

results and may change the method at some time in the future. AS OCDD/OCDF 

may be more soluble in toluene than methylene chloride, a change could result 

in quite a difference in total dioxin/furan--but not in TEF's. EPA must 

validate the final method on MWC s and establish an achievable limit in the 

NSPS and Emission Guidelines, regardless of sampling and analysis methodology. 

Response: EPA will revise Method 23 to specify toluene as the rinse 

solvent only if the test results show that the toluene does not make a 

significant difference in the total measured PCDD's and PCDF's. 

Commenter IV-D-06 

3.1 Comment: Section 3.3.13 Basic Alumina 

Pre-activated alumina is available from manufacturer's and can be used 

as is, provided blanks are free from interferences and carry-over. Activation 

before use should not be a prerequisite. 
P.13 

Response: The method has been revised to allow the use of activated 

alumina as received from the supplier. 

3.2 Comment: Section 3.3.15 Silica Gel Impregnated with Sulfuric 

Acid. ^ 

4 

In cases where greater capacity is required, OxyChem has successfully 

substituted celite for "silica gel. OxyChem suggests that celite should be 

listed as alternative solid support in this step, providing satisfactory QA/QC 

is demonstrated. 

Response: This is not the appropriate avenue to review requests for 

alternative methods. Requests for alternative methods should be submitted 

after the method is promulgated. The request should be in writing and should 

contain any supporting data. 

3.3 Comment: Section 5.2:2 Basic Alumina Column 

OxyChem has successfully employed the use of solvents other than 

methylene chloride and hexane to elute PCDDs and PCDFs from the basic alumina 

column. OxyChem suggests that solvents other than methylene chloride and 

hexane should be allowed, provided acceptable QA/QC is demonstrated. 

Response: See response to Comment 3.2 

Commenter IV-D-7 

4.1 Comment: We believe we have an alternative sample train condenser 

configuration which is superior to the one described in Method 23. The 

condenser-adsorbent cartridge are combined in a U-shaped arrangement where one 

arm of the U is the condenser and the other is the adsorbent cartridge. This 

allows the condenser to be submerged in the impinger train ice bath which 

makes it less fragile and eliminates the need for a Teflon line between the 

filter box and the impinger train allowing an all glass system. 
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Response: See response to Comment 3.2. 

4.2 Comment: The second modification involves the use of a glass 

extraction thimble as the canister for the sampling train. The size of the 

canister is such that 40 grams of XAD-2 resin can be incorporated. The beauty 

of this modification is that it eliminates all handling of XAD in the field 

and in the laboratory prior to extraction and analysis. Recovery of XAD after 

use is no longer a question as the material is not transferred prior to 

extraction. The standard operating procedure calls for removal of the 

canister after use, wrapping it in solvent rinsed aluminum foil and storing it 

at 4°C until extraction. For extraction, the foil is removed and the canister 

is placed inside the soxhlet extraction device for extraction of the compounds 

of interest. 

Response: See response to Comment 3.2. 

4.3 Comment: A third modification, which is more practice than 

equipment oriented, involves the use of a backup XAD canister periodically to 

document the capture efficiency. Basically the practice involves following 

the primary canister with a second canister every third run. The canister is 

extracted and analyzed separately from the rest of the sampling train. This 

data is intended to demonstrate the collection efficiency during the test 

program. Collection of the data over the years has provided data to back MM-5 

design. 

Response: While this is a good practice, we believe that spiking the 

adsorbent sampler with labeled PCDD's and PCDF's accomplishes the same result. 

Method 23 already requires that the adsorbent sampler be spiked before each 

test run. 

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Commenter IV-D-8 

5.1 Comment: In Section 5, no statement is made regarding the cleaning 

of laboratory glassware used for laboratory extraction and cleanup such as 

that made in 4.2.2.2 regarding the sampling equipment. Are the various 

pipettes used for chromatographic columns pre-cleaned or used "out-of-box?" 

Response: The method has been revised to require that all glassware be 

cleaned before use. 

5.2 Comment: In Section 5.2.3, is a step missing between the reduction 

of the volume to 200 fil and the sample analysis by GC/MS? For example, is the 

sample taken to a smaller volume? Should the

 13CU-1,2,3,4-TCDD and 13CIZ1,2,3,7,8,9-HxCDD Recovery Standards be added just prior to analysis? No 

mention of Recovery Standard addition is made in Method 23, but this step is 

needed. 

Response: The method has been revised to include the addition of the 

Recovery Standards just prior to analysis. The volume of the sample is not 

reduced below 200 #1 before analysis. 

5.3 Comment: In Section 6.1.1, what range of injection volumes are 

injected into the analyzer for initial calibration? 

Response: One IL\ of each the calibration solutions shown in Table 2 is 

injected into the analyzer for the initial calibration. The method has been 

revised to clarify this. 

5.4 Comment: The purposes of the TMQL is never explained. Will this 

be used to calculate detection limits for the nondetected 2, 3, 7, 8-

substituted isomers? Are analyzer peak areas of heights used for samplespecific detection limits (for example, see Method 8290)? Calculation of 

detection limits should be addressed in Method 23 so that results are 

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consistent from laboratory to laboratory. Detection limits are nontrivial, 

since they are often used for risk assessments. 

Response: The TMQL has been removed from the method and replaced with 

the minimum detection limit. An equation has been included in the method to 

4 

calculate the minimum detection limit. 

5.5 Comment: When reference is made to Method 5, does this refer to 

the stack particulate measuring protocol or to the "Modified Method 5" dioxin 

protocol? 

Response: All references to Method 5 are to the Method 5 in 40 CFR Part 

60, Appendix A. This is a procedure for measuring particulate matter. 

Commenter IV-D-9 

6.1 Comment: We support the development of standard sampling and 

analysis procedures for the measurement of polychlorinated dibenzo-p-dioxins 

and polychlorinated dibenzofurans. Uniform procedures are needed throughout 

the United States to provide a reliable data base for (1) further technical 

analysis to guide technology development, and (2) sound decisions in 

regulatory policy. 

Response: No response is needed. 

6.2 Comment: The condensation of vapor emissions prior to the 

adsorption trap is critical to obtain consistent and reliable data. 

Response: We believe that cooling the gas stream prior to its reaching 

the adsorbent sampler is critical to achieving maximum collection efficiency 

with the adsorbent sampler. Method 23 requires a condenser in front of the 

adsorbent sampler to accomplish this. We believe that this is sufficient. 

6.3 Comment: As noted above, substantial reductions in sampling and 

analytical costs, that don't sacrifice data quality, are greatly needed to (1) 

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provide low cost compliance testing and (2) promote the development of 

sufficient data for technology development. Alternative analytical techniques 

should be investigated to reduce costs. For example, analysis techniques for 

total dioxins and furans (i.e., the basis of the regulations; tetra through 

octa) should be evaluated as an alternative to analyzing the various 

homologues separately. 

Response: See the response to Comment 2.2. 

6.4 Comment: The limits of the capabilities of the proposed test 

method (EPA 23) are greatly needed. Most other standard EPA test methods have 

discussions of (1) detection limits, (2) accuracy, (3) potential 

interferences, (4) measurement repeatability, and (5) sample stability as part 

of Section 1. The proposed EPA 23 does not. The determination of these 

parameters and associated technical discussions are necessary to assess the 

appropriate use of this test method and the validity and reliability of the 

resulting data. 

Response: The method describes how each laboratory may calculate its 

own detection limits. Our test methods do not generally report accuracy data 

because it is not usually possible to assess the accuracy of emission sampling 

methods. The method has been designed to eliminate interferences by using gas 

chromatography to separate the compounds of interest from other compounds 

before measurement. Precision measurements have not yet been performed on the 

method. A statement about maximum storage time will be added to the method. 

Commenter IV-D-10 

7.1 Comment: The California Air Resources Board (ARB) has formally 

adopted test methods for determining PCDD/PCDF (ARB Method 428) and HCl (ARB 

Method 421) in emissions from stationary sources. The differences between the 

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P.18 

California adopted methods and the EPA proposed methods are not substantial. 

The applicability of ARB Method 428 does not exclude the applicability of EPA 

Method 23. For municipal waste combustors, the source matrix renders EPA 

Method 26 and ARB MethocM21 effectively identical in results. 

4 

We request that the EPA accept the use of the ARB adopted methods in 

California to satisfy EPA's proposed standard of performance for municipal 

waste combustors. This would obviate the need for duplicate testing to 

satisfy both state (or local) and federal requirements. This simplifies 

administration, and reduces the burden on the applicant. 

Response: While we would be happy to review requests for alternative 

procedures, this is not the appropriate avenue to submit such requests. 

Requests for alternative methods should be submitted after the method is 

promulgated. The request should be in writing and should contain any 

supporting data. 

7.2 Comment: Section 5.3 of the proposed EPA Method 23 requires that 

the SP-2331 column be used to quantify only 2,3,7,8-TCDF. This is different 

from: 

a. ARB Method 428 which requires that the concentration of 2,3,7,8-

substituted tetra to hexachlorinated PCDD and PCDF isomers be calculated from 

the results of the analysis of the sample extract on the SP-2331 column. 

b. SW-846 draft Method 8290 which requires that the concentration 

of all 2,3,7,8-substituted tetra to hexachlorinated isomer's other than 

2,3,4,7,8-PeCDF be calculated form analysis on the SP-2331 column. 

The proposed Method 23 does not allow the quantitation method 

required by ARB Method 428. This quantitation method is based on the advice 

of contract laboratories that have evaluated the ARB method. We suggest that 

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language be added to EPA Method 23 to allow quantitation of the 2,3,7,8-

substituted isomers on the SP-2331 confirmation column as long as the 

analytical laboratory documents the isomer specificity of that column with the 

proper calibration procedures and performance checks. 

« 

Response: Method 23 has been revised to specify that all isomers other 

than 2,3,7,8 tetra-chlorodibenzofuran (TCDF) be measured with a DB-5 column 

and that the 2,3,7,8 TCDF be measured with a DB-225 column. The method will 

also allow the tester the option of using other column systems provided the 

tester can demonstrate through calibration and performance checks that the 

columns will provide the necessary isomer separation. 

7.3 Comment: Analysis by High Resolution GC/Mass Spectrometry 

EPA's Method 23 requires analysis by high resolution gas 

chromatography (HRGC)/high resolution mass spectrometry (HRMS) whereas ARB 

Method 428 allows the use of either HRGC/HRMS or HRGC/low resolution mass 

spectrometry (LRMS). This is a choice that the ARB method allows the tester 

to make based on the target detection limits for the method and the type of 

source to be tested. ARB staff has found that at some sources other than 

municipal waste combustors, such as uncontrolled hospital waste incinerators, 

PCDD/PCDF concentrations are high enough that LRMS might be the preferred 

analytical method. 

Response: Testers always have the option of requesting alternative 

methods, but this is not the appropriate avenue to submit such requests. 

Requests for alternative methods should be submitted after the method is 

promulgated. The request should be in writing and should contain any 

supporting data. 

15 
P.20 

EPA reviewed other methods before beginning its program to collect data 

in support of a regulation for MWCs. The proposed Method 23 reflects the 

procedure used to collect this supporting data as required by law. 

7.4 Comment: ARB^s Method 238 internal standard requirement differs 

4 

from Method 23 only in the requirement for low resolution mass spectrometry. 

For low resolution mass "spectrometry, ARB Method 428 requires only one PCDF 

internal standard,

 13C-2,3,7,8-TCDF, compared to four for high resolution mass 

spectrometry. This was dictated by the limitations of the LRMS method. If 

Method 23 is revised to allow low resolution mass spectrometry as an option, 

this limitation should be addressed. 

Response: Because the method is not being revised to allow the option 

of low resolution mass spectrometry, it is not necessary to change the number 

of internal standards. 

7.5 Comment: Section 7.4 of Method 23 states that the toluene rinse 

must be analyzed separately from the other rinses and material collected from 

the sampling train, and that the results of this analysis must not be included 

in the estimate of total PCDD/PCDF collected by the sampling train. ARB 

Method 428, on the other hand, requires a benzene or toluene rinse which must 

be included in the estimate of total PCDD/PCDF collected by the sampling 

train. ARB Method 428 might give a higher PCDD/PCDF estimate of the 

concentration of the same gas stream than EPA Method 23. Nevertheless, the 

ARB has retained this requirement in the proposed amendment to Method 428 

(Attachment III) as measures to control PCDD/PCDF emissions in California have 

already been established or proposed based on data obtained with this version 

of Method 428. 

16 
P.21 

Response: This requirement affects only the New source Performance 

Standard for MWCs and any State regulations based on data collected by EPA. 

It would still be appropriate for the CARB to use the amended version of 

Method 428 to enforce Sfate regulations based on data obtained with the 

4 

revised Method 428. 

Commenter IV-D-11 

8.1 Comment: Specifications for the sampling probe have been omitted. 

Although it can be surmised that the probe should be of the same material as 

specified for the sampling nozzles, material specifications for the probe 

should be included. 

Response: Specifications for the probe were not omitted. They were 

included by reference to the probe specifications for Method 5. 

8.2 Comment: It has been our experience that most testing firms 

performing dioxin/furan sampling programs, purchase precleaned resin 

cartridges from laboratories that will subsequently perform the sample 

recovery and analyses. These cartridges must be sent to the client and 

returned via appropriate carrier. Although a chain of custody form may 

accompany these cartridges, they are exposed to contamination. It is our 

opinion that EPA should address this potential problem by requiring that a 

certified field/trip blank accompany the cartridges and be analyzed in the 

same manner as the sample to determine if the sample cartridges were subjected 

to contaminating atmospheres. 

Response: See response to Comment 1.4. 

8.3 Comment: The Department has successfully used a vacuum desiccator 

in lieu of the drying column arrangement for drying of the adsorbent following 

17 
P.22 

the cleaning procedure. Could EPA consider this technique as an alternative 

if a laboratory is not equipped with the drying column apparatus? 

Response: See response to Comment 3.2. 

Commenter IV-D-12 

9.1 Comment: We have observed that the preparation of AX-21 columns 

can be very critical to the success of the clean-up procedures. In 

particular, if not properly packed, AX-21 fines can end up adhering to the 

walls of the column or sometimes wash through the glass wool plug and get into 

the sample. This problem can be prevented through the addition of a celite 

plug on the final exit end of the column. 

Response: The method has been revised to allow this option. 

9.2 Comment: We have also observed that some of the higher congeners 

are difficult to elute from the AX-21 and suggest a larger volume of toluene 

be used in the final elution to insure adequate recovery. From a safety 

standpoint, it would be preferable to eliminate the use of benzene in the 

(1:1) benzene/ethylacetate elution. We have found that toluene can be used as 

a substitute for benzene; however, the elution profiles should be confirmed 

and necessary adjustments made in the volume of the fractions before the 

solvent switch is incorporated into the method. 

Response: See response to Comment 3.2. 

9.3 Comment: Method 23 specifies the use of an SP-2331 column for the 

isomer specific determination of 2,3,7,8-TCDF. By the usual standard used for 

defining and demonstrating isomer specificity for 2,3,7,8-TCDD (25 percent 

valley separation of 2,3,7,8-TCDD from the known closest eluting isomers to be 

demonstrated daily using the appropriate column performance isomer mix 

standard) the SP-2331 column could not be considered isomer specific. Through 

18 
P.23 

information obtained during the method development work conducted in the 

EPA/Paper Industry Cooperative Dioxin Screening Study, NCASI was able to 

identify critical isomers required to demonstrate the 2,3,7,8-TCDF isomer 

specificity of a DB-225.^ .These isomers and the gas chromatographic conditions 

4-

required for the isomer specific determination of 2,3,7,8-TCDF are presented 

in NCASI Technical Bulletin No. 551. Since this column has been demonstrated 

to be isomer specific for 2,3,7,8-TCDF, it should be incorporated into 

proposed Method 23 and all references to the use of the SP-2331 for isomer 

specific determination of 2,3,7,8-TCDF should be changed accordingly. 

Response: See response to Comment 7.2. 

9.4 Comment: Although not demonstrably isomer specific by the criteria 

generally accepted, the SP-2331 is considered to come the closest to 

generating isomer specific data for several 2,3,7,8-substituted penta and hexa 

CDD/CDF. Therefore, this column should continue to be included in the 

procedure and should be recommended for use in generating more specific or 

selective data on certain 2,3,7,8-substituted isomers. 

Response: See response to Comment 7.2. 

9.5 Comment: The method specifies an ionization potential of 70 ev. 

Some of the most commonly used instrumentation for high resolution GC/MS 

PCDD/PCDF analyses use ion sources especially designed for high sensitivity 

for PCDD/PCDF compounds. This was in part accomplished by using a lower 

ionization potential (between 30 to 40 ev) to minimize fragmentation, thereby 

retaining all the charge with the molecular ions which are used for 

identification and quantitation. By specifying a fixed ionization potential, 

no improvement in the quality of the data would be expected and an overall 

loss in sensitivity would result. The method should be modified to specify 

19 
P.24 

electron impact ionization but should not specify a specific ionization 

potential. This would be in keeping with other published or draft high 

resolution MS PCDD/PCDF procedures. 

Response: The method has been revised to delete the voltage 

specification for the ionization source. 

9.6 Comment: The method specifies acceptable recovery ranges for the 

internal standards but allows that if the criteria are not met, the data would 

be considered acceptable if the internal standard signal to noise ratio was 

greater than or equal to 10:1. A minimum S/N ratio of 10:1 would be a useful 

QA/QC criteria in and of itself and we recommend that it be incorporated into 

the method for all analyses, but an acceptable S/N ratio cannot be used to 

compensate for poor recoveries. If the losses occur during the extraction 

procedure, the recovery of the internal standards cannot totally correct for 

these losses since it is currently impossible to insure (or demonstrate) that 

the internal standards distribute themselves in the matrix exactly like the 

native analytes. Thus, recovery of the Internal Standard can overestimate 

native analyte recovery. The isotopic dilution procedure can adequately and 

accurately correct for losses which occur during the clean-up procedures. For 

these reasons, analyses with unacceptable internal standard recoveries should 

be rejected as unreliable. 

Response: The method has been revised to limit acceptable recoveries of 

internal standards to between 40 and 130 percent for the tetra- through 

hexachlorinated isomers and between 25 and 130% for the higher hepta- and 

octachlorinated homologues. 

9.7 Comment: These same concerns apply to the use of the surrogate 

spike recoveries to correct for low recovery efficiency. Until it can be 

20 
P.25 

unambiguously established that the surrogate spikes exactly mimic the native 

analytes, they cannot be used to correct for low recoveries. 

Response: See response to Comment 1.2. 

9.8 Comment: Although allowing a mass spectrometer resolution as low 

as 8,000 may improve sensitivity, the generally accepted minimum resolution 

for a "high resolution MS" procedure is 10,000. This is intended to minimize 

potential false positives or mis-identifications. In keeping with this 

generally accepted standard, a minimum MS resolution of 10,000 should be 

specified. 

Response: The method has been revised to define high resolution mass 

spectrometry as having a minimum resolution of 10,000. 

9.9 Comment: In order to monitor for drift in the resolution or tune 

of the mass spectrometer, monitoring of a lock mass check channel is generally 

required in high resolution MS PCDD/PCDF protocols. Instrumentation suitable 

for use in Method 23 should be capable of performing this QA/QC function. 

Since this provides added assurance of the instruments' performance at the 

time of analysis, monitoring and reporting a lock mass check channel should be 

required in the procedure. 

Response: The method has been revised to require setting a lock mass 

and monitoring a check channel. 

Method 26 

1. Commenter IV-D-2 

1.1 Comment: We strongly support EPA's adoption of ion chromatography 

for chloride ion detection as part of Method 26. This analytical technology 

is clearly the method of choice for this type of determination because of the 

21 
P.26 

high degree of specificity and linearity which is easily attained using a 

number of commercially available instruments. 

Response: No response necessary. 

1.2 Comment: We ftrge the Agency to develop quality control samples for 

4. 

voluntary use, similar to the metal and organic quality control samples 

distributed by the EPA's Cincinnati, Ohio office. 

Response: Quality control samples for Method 26 are currently under 

development and will be made available in the future. These samples will be 

available for voluntary practice and in validating Method 26 analyses when 

making compliance determinations. 

2. Commenters IV-D-2, IV-D-5 

Comment: We are concerned that Method 26 as proposed may be prone to 

significant interferences from fine particulates present in some emission 

sources. We are particularly concerned that the method currently has no way 

of detecting particulate breakthrough in the filter. This would result in a 

significant error if particulate chloride salts are present. A determination 

of the various cation concentrations in the impingers such as NH4

+, Fe2+, Fe3+, 

Al3+, Ba2+, Ca2+, K+, Mg2+, and Na+ should be done to verify whether 

breakthrough has occurred. Runs having cation levels significantly above 

baseline levels or greater than 10 percent of the CI" concentration should be 

considered invalid. The presence of any of these cations would indicate the 

likely penetration of the filter by volatile or fine particulate salts. The 

method should also be modified to more clearly indicate circumstances where 

these interferences would prohibit the use of the method. 

Response: The specified Method 26 filter uses a mat configuration. The 

mat configuration should prevent fine particulate matter from penetrating the 

22 
P.27 

filter (see response to comment 6.1). The specifications describing the 

filter have been clarified to emphasize this point and ease concern about 

particulate penetration. 

We do not feel an^impinger analysis to determine filter breakthrough is 

4 

necessary for cations of non-volatile chloride salts, such as calcium chloride 

(CaCl2), that would be expected in emissions from municipal waste combustors. 

Filter penetration by more volatile particulate chloride salts, such as 

ammonium chloride (NH4C1), may occur when testing sources such as cement 

kilns. However, the method was not developed for use at cement kilns, and 

these sources will be granted a waiver from the hydrochloric acid (HCl) 

testing requirements. 

3. Commenters IV-D-2, IV-D-5 

Comment: We object to Method 26 being used at cement kilns. Data shows 

the unlikelihood of emissions containing HCl due to background levels of 

various cations. Chlorides detected by the method result from volatile 

chloride salts such as NH4C1 and other salts instead of HCl. Although the 

method states that volatile chloride salts are obvious interferences, such a 

statement has not prevented various State regulatory agencies from requiring 

this method for testing cement kilns. This serious interference problem 

should be clearly and fully acknowledged for cement kilns so that industry 

will not be held hostage by the Agency's inability to develop a method for 

measuring regulated emissions. Proposed Method 26 has not been thoroughly 

evaluated and validated for use on the broad class of municipal 

waste combustors to be regulated. We recommended that the method be limited 

to devices for which it has been validated - municipal waste incinerators. 

23 
P.28 

Response: The method was not developed for use at cement kilns; 

therefore the quality of data obtained by sampling this matrix with Method 26 

is unknown. Cement kilns that qualify as MWCs will be granted a waiver from 

the HCl testing requirements. 

4. Commenter IV-D-10 

Comment: Proposed Method 26 uses a 0.1N sulfuric acid solution to 

absorb HCl selectively and avoid free chlorine (Cl2) interference if present 

in the stack. The method is otherwise very similar to California Air 

Resources Board (ARB) Method 421. Since Cl2 gas is theoretically negligible 

in incinerator flue gas, and no experimental evidence is available to show 

that Cl2 interference commonly exists, we believe both methods will produce 

indistinguishable results when incinerators are tested. Therefore, the 

correction for Cl2 is unnecessary. We request that EPA accept the use of ARB 

Method 421 to satisfy the HCl testing requirements at MWCs to obviate the 

need for duplicate testing to satisfy both State and Federal requirements. 

Response: The Agency, as well, is not privy to experimental evidence 

showing Cl2 can be present in MWC emissions. However, we do feel that Cl2 

might be present under certain conditions. To minimize the interference in 

these cases, we feel the modified absorbing solution is warranted over 

adopting ARB Method 421. 

5. Commenter IV-D-11 

Comment: The title of proposed Method 26 implies that it is appropriate 

for all stationary sources. This is not the case. Method 26 was researched, 

developed, and tested at MWC s and is designed to capture HCl in its gaseous 

form. The method uses a constant sampling rate and a sampling nozzle 

positioned in the downstream direction to prevent a positive bias from CaCl2 

24 
P.29 

from lime injection systems typically installed on MWCs . Hydrochloric acid 

doesn't really like to be HCl gas, it would rather be an HCl aerosol. 

Proposed Method 26 effectively eliminates the possibility of measuring this 

aerosol. It is our opinion that EPA has overlooked sources which may have 

particulate and vapor forms of HCl which would necessitate sampling 

isokinetically in the conventional Method 5 mode. r^\ 

y Response: We agree that Method 26 is applicable only to municipal waste 

combustors. The method title does not specifically mention MWC s to allow a 

broader application to other sources that may require HCl testing in the 

future. The CaCl2 from control devices will not be an interferant when the 

specified filter is used (Section 2.1.5 of the method). 

We agree that isokinetic sampling may be preferred over sampling at a 

constant rate. We have compared Method 26 and Method 5, sampling 

isokinetically, at an MWC and found that the two methods gave the same 

results. However, at other MWC s where the HCl aerosol may have a larger 

aerodynamic diameter, isokinetic sampling may give higher HCl results than 

Method 26. Therefore, we are continuing to assess the method in this respect 

and are evaluating an isokinetic sampling method for future use. 

6. Commenter V-D-12 

6.1 Comment: The filter media specified in the proposed method is 

Pallflex TX40H175 or equivalent. This filter is constructed of PTFE on a 

glass fiber support and is 25 percent glass fiber. The filter media used in 

the development of this method, as reported in the referenced document, was 

Schleicher and Schuell #41-01510. This filter is composed of PTFE on a 

polypropylene support. In light of reports that HCl can be lost on glass 

fiber filters, the use of Pallflex TX40H175 medium may not be appropriate. 

25 
P.30 

Additionally, we suggest that instead of specifying the filter medium by brand 

name, the method should specify filter efficiency and acceptable materials of 

construction. 

Response: The Pallflex TX40H175 filter was selected because it is in a 

mat (as opposed to a laminate) configuration and contains the maximum amount 

of Teflon consistent with this configuration. The loss of HCl due to 

adsorption on the glass portion of the filter should be minimal when the 

purging procedure specified in the method is used. We feel that specifying a 

mat configuration is a more effective means of eliminating fine particulate 

matter from penetrating the filter than specifying a DOP or other efficiency 

rating. The filter specifications have been revised to clarify this point and 

to allow alternative brands that are constructed of acceptable materials. 

6.2 Comment: The method states that either an in-stack or an out-ofstack filter can be used. However, an out-of-stack filter and filter holder 

were not evaluated during the method development studies. We suggest that the 

method be evaluated using an out-of-stack filter and filter holder to address 

the following questions: First, how much HCl is lost in the out-of-stack 

filter, which exposes more surface area of the glass fiber in the filter to 

the source gas than the in-stack filter method? Second, what would be the 

impact of using larger filters and filter holders which may be required for 

sources with high particulate matter concentrations? Third, what is the 

effect on HCl of the glass frit used in a glass or quartz filter holder? 

Response: We have specified an out-of-stack, instead of an in-stack 

filter, to minimize the possible loss of HCl due to moisture condensation. 

Also, we have specified a Teflon or quartz filter holder (as opposed to glass) 

to minimize HCl losses. A Teflon, not a glass frit, should be used to support 

26 
P.31 

.' * 

the filter. The impact of using larger filters and filter holders should be 

negligible if they are constructed mostly of Teflon; this is especially true 

since the sampling system upstream from the first impinger is purged with 

stack gas prior to sampling. We have clarified the specification for the 

filter and filter holder. * 

6.3 Comment: The description of the filter locations presented in 

Section 2.1.5 appears to be incomplete. 

Response: This has been clarified. 

6.4 Comment: In the method evaluation report referenced in the 

proposal, there are no data on sample recovery through the complete sampling 

system except for spiked field samples. Spiking field samples will not reveal 

constant losses of HCl (i.e., losses which are not concentration dependent). 

Sample recovery should be determined through the complete sample train using 

alternatively an in-stack and an out-of-stack filter. This will indicate 

whether any HCl is lost to reaction with alkaline particulate matter collected 

on the filter. These tests should be conducted using cylinder gas mixed with 

humidified air rather that dry air. 

Response: There is evidence (internal memo on results of recent 

laboratory experiments) which indicates that the loss of HCl to alkaline 

particulate matter is small, if any. There is also evidence in the open 

literature which indicates that some HCl is lost. To minimize the 

significance of any bias due to reactions of HCl with particulate matter 

collected on the filter, we have specified a minimum sampling time of one 

hour. 

27 
P.32 

• ' «' 'a * «. 

LIST OF COMMENTERS 

Docket Number A-89-11 

Docket Item-Number Commenter/Affi1i ation 

IV-D-1 ^. Thomas M. Allen, Director 

Division of Air Resources 

New York State Department of 

Environmental Conservation 

50 Wolf Road 

Albany, New York 12233 

IV-D-2 David Gossman, President 

Gossman Consulting, Inc. 

45W962 Plank Road 

Hampshire, Illinois 60140 

IV-D-3 David B. Sussman, Vice President 

Ogden Martin Systems, Inc. 

5301 Eisenhower Avenue 

Alexandria, Virginia 22304 

IV-D-4 . Rich Stafford 

Denver, Colorado 80209 

IV-D-5 Douglas Y. Mac Iver, Manager 

Environmental Engineering 

Southdown, Inc. 

Citicorp Center, Suite 2400 

1200 Smith Street 

Houston, Texas 77002-4468 

IV-D-6 Timothy J. Yagley, 

Environmental Chemist 

Occidental Chemical Corporation 

Occidental Chemical Center 

360 Rainbow Boulevard South 

Niagra Falls, New York 14302 

IV-D-7 John T. Kane, Jr., Manager 

Air Quality Engineering 

Keystone Environmental Resources, Inc. 

3000 Tech Center Drive 

Monroeville, Pennsylvania 15146 

IV-D-8 Jean M. Czuzwa 

Babcock & Wilcox 

1562 Beeson Street 

Alliance, Ohio 44601 

28 
1 '.•'.• •*. 

P.33 

IV-D-9 

IV-D-10 

IV-D-11 

IV-D-12 

IV-D-13 

John Zink Company 

George Lew, Chief 

Engineering Evaluation Branch 

Monitoring and Laboratory Division 

Air Resources Board 

1102 Q Street 

Sacramento, California 95812 

Ben A. Brodovicz, Chief 

Division of Technical Services and 

Monitoring 

Bureau of Air Quality Control 

Commonwealth of Pennsylvania 

Department of Natural and Economic 

Resources 

Harrisburg, Pennsylvania 17105-2357 

John E. Pinkerton, Program Director 

Air Quality 

National Council of the Paper Industry 

for Air and Stream Improvement, Inc. 

260 Madison Avenue 

New York, New York 10016 

Brian Murphy 

Private Citizen 

29 

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