[Federal Register: September 7, 2007 (Volume 72, Number 173)]
[Rules and Regulations]
[Page 51493-51531]
[DOCID:fr07se07-17]

-----------------------------------------------------------------------

Part II

Environmental Protection Agency

-----------------------------------------------------------------------

40 CFR Parts 60, 72 and 75

Two Optional Methods for Relative Accuracy Test Audits of Mercury
Monitoring Systems Installed on Combustion Flue Gas Streams and Several
Amendments to Related Mercury Monitoring Provisions; Final Rule

-----------------------------------------------------------------------

ENVIRONMENTAL PROTECTION AGENCY

40 CFR Parts 60, 72 and 75

[EPA-HQ-OAR-2007-0164, FRL-8459-8]
RIN 2060-AO01

Two Optional Methods for Relative Accuracy Test Audits of Mercury
Monitoring Systems Installed on Combustion Flue Gas Streams and Several
Amendments to Related Mercury Monitoring Provisions

AGENCY: Environmental Protection Agency (EPA).

ACTION: Direct final rule.

-----------------------------------------------------------------------

SUMMARY: EPA is taking direct final action on two optional methods for
relative accuracy audits of mercury monitoring systems installed on
combustion flue gas streams and several amendments to related mercury
monitoring provisions. This action approves two optional mercury (Hg)
emissions test methods for potential use in conjunction with an
existing regulatory requirement for Hg emissions monitoring, as well as
several revisions to the mercury monitoring provisions themselves. This
action is in regard to the testing and monitoring requirements for
mercury specified in the Federal Register on May 18, 2005. Since that
publication, EPA has received numerous comments concerning the
desirability of EPA evaluating and allowing use of the measurement
techniques addressed in the two optional methods in lieu of the methods
identified in the cited Federal Register publication, as they can
produce equally acceptable measures of the relative accuracy achieved
by Hg monitoring systems. This action allows use of these two optional
methods entirely at the discretion of the owner or operator of an
affected emission source in place of the two currently specified
methods. This direct final rule also amends Performance Specification
12A by adding Methods 30A and 30B to the list of reference methods
acceptable for measuring Hg concentration and the Hg monitoring
provisions of May 18, 2005, to reflect technical insights since gained
by EPA which will help to facilitate implementation including
clarification and increased regulatory flexibility for affected
sources.

DATES: This rule is effective on November 6, 2007 without further
notice, unless EPA receives adverse comment by October 9, 2007. If EPA
receives adverse comment, EPA will publish a timely withdrawal in the
Federal Register informing the public that some or all of the
amendments in this rule will not take effect.

ADDRESSES: Submit your comments, identified by Docket ID No. EPA-HQ-
OAR-2007-0164, by one of the following methods:
     http://www.regulations.gov. Follow the on-line instructions for

submitting comments.
     E-mail<EMAIL_ADDRESS>     Fax:<PHONE_NUMBER>.
     Mail: Two Optional Methods for Relative Accuracy Test
Audits of Mercury Monitoring Systems Installed on Combustion Flue Gas
Streams and Several Amendments to the Related Mercury Monitoring
Provisions, Environmental Protection Agency, Mailcode: 2822T, 1200
Pennsylvania Avenue, NW., Washington, DC 20460. Please include a total
of two copies.
     Hand Delivery: EPA Docket Center, 1301 Constitution
Avenue, NW., EPA Headquarters Library, Room 3334, EPA West Building,
Washington, DC 20460. Such deliveries are only accepted during the
Docket's normal hours of operation, and special arrangements should be
made for deliveries of boxed information.
    Instructions: Direct your comments to Docket ID No. EPA-HQ-OAR-
2007-0164. EPA's policy is that all comments received will be included
in the public docket without change and may be made available online at
http://www.regulations.gov, including any personal information provided,

unless the comment includes information claimed to be Confidential
Business Information (CBI) or other information whose disclosure is
restricted by statute. Do not submit information that you consider to
be CBI or otherwise protected through http://www.regulations.gov or e-mail.

The http://www.regulations.gov Web site is an ``anonymous access'' system,

which means EPA will not know your identity or contact information
unless you provide it in the body of your comment. If you send an e-
mail comment directly to EPA without going through http://www.regulations.gov,

your e-mail address will be automatically captured and included as part
of the comment that is placed in the public docket and made available
on the Internet. If you submit an electronic comment, EPA recommends
that you include your name and other contact information in the body of
your comment and with any disk or CD-ROM you submit. If EPA cannot read
your comment due to technical difficulties and cannot contact you for
clarification, EPA may not be able to consider your comment. Electronic
files should avoid the use of special characters, any form of
encryption, and be free of any defects or viruses. For additional
information about EPA's public docket, visit the EPA Docket Center
homepage at http://www.epa.gov/epahome/dockets.htm.

    Docket: All documents in the docket are listed in the
http://www.regulations.gov index. Although listed in the index, some

information is not publicly available, e.g., CBI or other information
whose disclosure is restricted by statute. Certain other material, such
as copyrighted material, will be publicly available only in hard copy.
Publicly available docket materials are available either electronically
in http://www.regulations.gov or in hard copy at the Two Optional Methods for

Relative Accuracy Audits of Mercury Monitoring Systems Installed on
Combustion Flue Gas Streams Air and Radiation Docket, EPA/DC, EPA West
Building, EPA Headquaters Library, Room 3334, 1301 Constitution Avenue,
NW., Washington, DC. The Public Reading Room is open from 8:30 a.m. to
4:30 p.m., Monday through Friday, excluding legal holidays. The
telephone number for the Public Reading Room is<PHONE_NUMBER>, and the
telephone number for the Air and Radiation Docket is<PHONE_NUMBER>.

FOR FURTHER INFORMATION CONTACT: Either Mr. William Grimley, Office of
Air Quality Planning and Standards, Air Quality Assessment Division,
Measurement Technology Group (E143-02), EPA, Research Triangle Park, NC
27711, telephone<PHONE_NUMBER>, facsimile number<PHONE_NUMBER>, e-
mail address<EMAIL_ADDRESS>or Ms. Robin Segall, Office of
Air Quality Planning and Standards, Air Quality Assessment Division,
Measurement Technology Group (E143-02), EPA, Research Triangle Park, NC
27711, telephone<PHONE_NUMBER>, facsimile number<PHONE_NUMBER>, e-
mail address<EMAIL_ADDRESS>
SUPPLEMENTARY INFORMATION:

I. Why is EPA using a Direct Final Rule?

    EPA is publishing this rule without a prior proposed rule because
we view this as a noncontroversial action and anticipate no adverse
comment. The most important benefit of direct final rulemaking for this
action is to provide: (1) Additional reference method options, and (2)
judicious revisions to mercury monitoring provisions specified in the
Federal Register on May 18, 2005 that, if successful, relieve affected
facilities of uncertainty regarding final emission monitoring
requirements and certification details as opposed to waiting through a
potentially protracted proposal/final

rulemaking process. Insofar as the two methods are concerned, EPA
believes that they contain the necessary elements to generate
acceptable data quality without being unduly burdensome. Through
experience gained from developing existing performance based methods
and trading rules, EPA has learned to identify test method criteria
significant to effective rule implementation. EPA believes each of the
two methods adopted in this action contain adequate specific criteria
and procedures essential to the accurate measurement of Hg emissions,
without adversely compromising the goals of performance-based
methodology. EPA will continue to support and advance the principles
and practicality of these methods by adding detailed method application
information to facilitate their use to the Web site http://www.epa.gov/airmarkets/
 as it becomes available. Since use of either of these

methods is not mandatory, but optional, there should be no objection to
their availability. Regarding the amendments to the Hg emission
monitoring provisions of 40 CFR parts 72 and 75, these amendments
reflect EPA's increased technical understanding since the May 18, 2005
rulemaking. However, in the ``Proposed Rules'' section of today's
Federal Register, we are publishing a separate document that will serve
as the proposed rule to approve provisions, if any, of this direct
final rule that receive relevant adverse comments on this direct final
rule. We will not institute a second comment period on this action. Any
parties interested in commenting must do so at this time. For further
information about commenting on this rule, see the ADDRESSES section of
this document.
    If EPA receives adverse comment on one or more distinct provisions
of this rulemaking, we will publish a timely withdrawal in the Federal
Register indicating which provisions we are withdrawing and informing
the public that those provisions will not take effect. The provisions
that are not withdrawn will become effective on the date set out above,
notwithstanding adverse comment on any other provision. We would
address all public comments in a subsequent final rule based on the
proposed rule.

II. Does This Action Apply to Me?

    Regulated Entities. The regulated categories and entities affected
by this direct final rule include:

------------------------------------------------------------------------
                                                  Examples of regulated
            Category                NAICS \a\            entities
------------------------------------------------------------------------
Industry.......................          221112  Fossil fuel-fired
                                                  electric utility steam
                                                  generating units.
Federal government.............      \b\ 221122  Fossil fuel-fired
                                                  electric utility steam
                                                  generating units owned
                                                  by the Federal
                                                  government.
State/local governments........      \b\ 221122  Fossil fuel-fired
                                                  electric utility steam
                                                  generating units owned
                                                  by municipalities.
Tribal governments.............          921150  Fossil fuel-fired
                                                  electric utility steam
                                                  generating units in
                                                  Indian country.
------------------------------------------------------------------------
\a\ North American Industry Classification System.
\b\ Federal, State, or local government-owned and operated
  establishments are classified according to the activity in which they
  are engaged.

    This table is not intended to be exhaustive, but rather provides a
guide for readers regarding entities likely to be affected by this
direct final rule. If you have any questions regarding the
applicability of this direct final rule to a particular entity, consult
either the air permit authority for the entity or your EPA regional
representative as listed in 40 CFR 63.13.

III. Where Can I Obtain a Copy of This Action?

    In addition to being available in the docket, an electronic copy of
this direct final rule is also available on the World Wide Web through
the Technology Transfer Network (TTN). Following signature, a copy of
this direct final rule will be posted on the TTN's policy and guidance
page for newly proposed or promulgated rules at the following address:
http://www.epa.gov/ttn/oarpg. The TTN provides information and

technology exchange in various areas of air pollution control.

IV. How Is This Document Organized?

    The information presented in this preamble is organized as
follows:

I. Why Is EPA Using a Direct Final Rule?
II. Does This Action Apply to Me?
III. Where Can I Obtain a Copy of This Action?
IV. How Is This Document Organized?
V. Background
VI. This Action
VII. Statutory and Executive Order Reviews
    A. Executive Order 12866: Regulatory Planning and Review
    B. Paperwork Reduction Act
    C. Regulatory Flexibility Act
    D. Unfunded Mandates Reform Act
    E. Executive Order: 13132: Federalism
    F. Executive Order 13175: Consultation and Coordination With
Indian Tribal Governments
    G. Executive Order 13045: Protection of Children From
Environmental Health and Safety Risks
    H. Executive Order 13211: Actions That Significantly Affect
Energy Supply, Distribution, or Use
    I. National Technology Transfer and Advancement Act
    J. Executive Order 12898: Federal Actions To Address
Environmental Justice in Minority Populations and Low-Income
Populations
    K. Congressional Review Act

V. Background

    On May 18, 2005, in the preamble of the Clean Air Mercury Rule
(CAMR) (70 FR 28608), EPA stated its intention to propose and
promulgate an instrumental reference method as an alternative to the
use of ASTM Method D6784-02 (the Ontario Hydro Method) to perform
Relative Accuracy Test Audits (RATAs) of Hg continuous emission
monitoring systems (CEMS) and sorbent trap monitoring systems used to
monitor Hg emissions from coal-fired power plants.
    In comments on the proposed CAMR, commenters had two primary
objections to the use of the Ontario Hydro Method as the reference test
method for RATAs. Some expressed concern that the complexity of this
wet chemical method could lead to results that would cause a properly
functioning Hg CEMS to fail a RATA. Other commenters noted that, unlike
instrumental reference methods used to audit CEMS for SO2
and NOX that provide real-time values, test results from the
Ontario Hydro Method can take weeks to be received from the laboratory.
Commenters stated that this time lag can lead to implementation
problems with regard to both missing data and emissions reporting.
    Since the CAMR was promulgated, EPA has proposed changes to 40 CFR
part 75, which would allow the use of EPA Method 29, with enhanced
quality-assurance procedures, as an alternative Hg reference method (71
FR 49257; August 22, 2006). Although Method 29 is somewhat simpler than
the Ontario Hydro Method and is more familiar to stack testers and
State regulatory agencies, it is also a wet chemistry method and is,
therefore, subject to the same limitations that make the Ontario Hydro
method less than optimal for RATA testing.
    In view of these considerations, EPA believes that for RATA
testing, an instrumental Hg reference method

would be preferable to both the Ontario Hydro Method and to Method 29.
An instrumental method would provide real-time data that would best
facilitate implementation of a mercury cap and trade program.
Therefore, this action approves a performance-based instrumental
reference method for measuring Hg emission concentrations.
    Another commenter to the proposed CAMR recommended that the sorbent
trap monitoring approach, now specified in 40 CFR part 75, appendix K,
be considered for use as a reference method. Although EPA did not
commit to establishing a sorbent trap reference method at the time of
CAMR promulgation, stakeholder interest in this methodology has
increased significantly. In an August 22, 2006 Federal Register notice,
EPA solicited comment on the use of sorbent trap technology for Hg
reference method testing, and numerous supportive comments were
received. In view of this, we initiated a review of available
historical test data where concurrent measurements of Hg concentration
were made with sorbent trap systems and either the Ontario Hydro Method
or Method 29. These data, taken together with additional supporting
data from recent field tests that were performed after the CAMR was
promulgated, suggest that using the sorbent trap methodology for Hg
reference method testing is viable. The Hg sorbent trap approach is
less onerous to use than either Ontario Hydro or Method 29, and
although it does not measure real-time Hg concentrations, a thermal
technique can be used to analyze the samples on the same day that they
are collected, facilitating RATA testing in the context of a cap and
trade program. Therefore, this action also approves a sorbent trap
reference method for Hg, as an alternative to the Ontario Hydro Method
and Method 29.
    This direct final rule also includes several carefully considered
amendments to the Hg emission monitoring provisions of 40 CFR parts 72
and 75. EPA believes these amendments will facilitate implementation of
the CAMR by clarifying portions of that rule and by providing added
regulatory flexibility to the affected sources.

VI. This Action

    This direct final rule allows for the earliest possible use of two
optional reference test methods for measuring total vapor phase mercury
emissions from stationary sources as well as several related amendments
to the Hg monitoring provisions of the CAMR. Both an instrumental test
method and a sorbent trap test method for measurement of total vapor
phase mercury emissions are being added to Appendix A-8 of 40 CFR part
60 as approved alternatives to the Ontario Hydro Method and EPA Method
29 to perform RATAs of installed mercury monitoring systems. The two
methods are discussed below, and the related amendments are explained
in detail later in this section.
    The first method being added to appendix A-8 of 40 CFR part 60
today is titled ``Method 30A--Determination of Total Vapor Phase
Mercury Emissions from Stationary Sources (Instrumental Analyzer
Procedure).'' In Method 30A, a sample of the effluent gas is
continuously extracted and conveyed to an analyzer capable of measuring
the total vapor phase Hg concentration. Elemental and oxidized mercury
(i.e., Hg\0\ and Hg+\2\) may be measured separately or
simultaneously but, for purposes of this method, total vapor phase Hg
is the sum of Hg\0\ and Hg+\2\. Method 30A provides test
program-specific verification of method performance using a dynamic
spiking approach, coupled with other performance criteria, which
include system calibration, interference testing, and system integrity/
drift checks. The dynamic spiking requirement, which is a gaseous
``method of standard additions,'' is the only part of Method 30A not
parallel to the routinely applied instrumental reference methods used
to perform relative accuracy testing of CEMS for SO2 and
NOX. The dynamic spiking procedure is included in Method 30A
to characterize measurement bias for Hg, which can be highly reactive
on a site-specific basis (i.e., for each emissions sample matrix), with
recovery criteria set to ensure that the bias is held to a minimal
level. All performance requirements of Method 30A must be met for the
data to be considered valid. The availability of an instrumental
reference method for Hg testing is consistent with the approach EPA has
taken in the successful Acid Rain and NOX Budget emissions
trading programs.
    Method 30A is performance based in keeping with the criteria
established under our Notice of Intent to Implement Performance Based
Measurement Systems for Environmental Monitoring (62 FR 52098, October
6, 1997). Use of the performance-based measurement approach will allow
for continued development and application of new, improved, and more
cost-effective Hg measurement technologies while ensuring the
collection of data of known quality.
    Based on EPA's experience in conducting test programs to evaluate
the procedures and performance criteria included in Method 30A, EPA
recognizes that although prototypes of all equipment needed to perform
this method have been successfully demonstrated in the field, at
present the equipment needed to follow all procedures required by the
method is commercially available only on a limited basis, and is being
further refined. One of the issues of greatest concern in the
development of an instrumental reference method for Hg has been the
design of the sampling probe. Most of the commercially-available probes
suitable for Hg measurement are very heavy (over 100 lbs.) making it
difficult to move the probe from point-to-point and port-to-port for Hg
stratification testing and/or sample traverses. Much progress is being
made in probe redesign. One manufacturer has recently developed a probe
that weighs less than 40 lbs., samples at significantly lower flow
rates, and is suitable for dynamic spiking. Additional field testing of
this probe and others currently under development is underway, and EPA
plans to continue to actively encourage equipment development and
evaluation. To encourage the use of Method 30A, including further
development of the supporting equipment, which we believe will
eventually enable source testers to perform Hg monitoring system RATAs
more efficiently and will become the reference method of choice for
many testing companies and affected sources, we are deferring the
requirement for implementation of the dynamic spiking and Hg
stratification test procedures until January 1, 2009. EPA believes this
deferral is reasonable because Hg monitoring data reported to EPA in
2009 will not be used in the trading of Hg allowances, as allowance
accounting under the CAMR does not begin until 2010. Source testers are
encouraged to use this time to acquire the necessary equipment and
familiarize themselves with these procedures. Also, for all emissions
test programs and RATAs performed under CAMR prior to January 1, 2009,
we are allowing either: (1) A 12-point traverse for sulfur dioxide
(SO2) to be substituted for a 12-point Hg traverse, in cases
where stratification testing is used to determine the appropriate
number and location of the reference method sampling points, or (2) use
of the alternate three-point traverse line (0.4, 1.2, and 2.0 meters
from the stack wall) as specified in section <IP_ADDRESS> of Performance
Specification 2 (40 CFR part 60, appendix B). We

believe that in the short-term, these temporary deferrals will
encourage the application of Method 30A and will help affected CAMR
sources meet the January 1, 2009 deadline for initial certification of
the required Hg monitoring systems. Several additional Method 30A
development considerations are worthy of note. A preliminary draft of
Method 30A was first available for public consideration on an EPA Web
site (http://www.epa.gov/ttn/emc/) on February 28, 2006. Since that time, EPA

and several stakeholder groups have evaluated the various technical
aspects of the method. Based on the combined laboratory and field
observations, EPA has been able to simplify several procedural
requirements that we believe are essential to the method. The dynamic
spiking requirement (for test program-specific verification of
measurement system data quality) has been reduced to only a pretest
requirement. The interference test has been made optional. The three-
point system calibration error test using Hg+\2\ has been
streamlined to a system integrity check using a zero gas and a single
upscale Hg+\2\ gas. Another change has been to relax the
Hg\0\ calibration error specification from 2 percent to 5 percent of
span, in recognition of the fact that this procedure is a check of the
entire measurement system, as well as the current knowledge regarding
the uncertainty of NIST traceable standards. EPA does plan, however, to
reconsider this specification relaxation as more field data become
available. A final consideration in development of Method 30A has been
the requirement for calibration with both Hg\0\ and Hg+\2\.
Some stakeholders have recommended that we eliminate the Hg\0\
calibration and rely solely on the Hg+\2\ calibration. EPA,
however, believes this approach would not be adequate, because if only
Hg+\2\ were used, instrument calibration response adjustment
could compensate for an unknown amount of converter inefficiency, which
would then result in an inaccurate total mercury measurement in
situations where Hg\0\ is an appreciable fraction of the total stack
gas Hg.
    The second method being added to appendix A-8 of 40 CFR part 60
today is titled ``Method 30B--Use of Sorbent Traps to Measure Total
Vapor Phase Mercury Emissions from Coal-Fired Combustion Sources.'' In
Method 30B, a sample of the effluent gas is continuously drawn through
a series of tubes containing activated carbon or another sorbent
material. After sampling, the tubes are sealed. The Hg captured by the
sorbent is then either: (1) Thermally desorbed and analyzed; or (2) the
tubes are transferred to a laboratory for extraction of Hg and
analysis. Like Method 30A, Method 30B is a performance-based method and
contains performance specifications and procedures for hardware
selection and calibration, sorbent spiking, and analytical recovery/
analysis which allow for development and application of new, improved,
and more cost-effective Hg measurement technologies while still
ensuring the collection of data of known quality. In particular, Method
30B contains five key measurement performance tests designed to ensure:
(1) Selection of a sorbent and analytical technique combination capable
of quantitative collection and analysis of gaseous Hg, (2) collection
during field testing of enough Hg on each sorbent trap to be reliably
quantified, and (3) adequate performance of the method for each test
program.
    In considering development of a sorbent trap-based reference
method, EPA has reviewed historical emissions data where sorbent trap
measurement systems were operated concurrently with either the Ontario
Hydro Method or Method 29 (40 CFR part 60, appendix A-8). EPA has also
conducted several field test evaluations of sorbent trap systems versus
the Ontario Hydro Method in collaboration with the Electric Power
Research Institute (EPRI). Based on these efforts, we have concluded
that a sorbent trap-based technique coupled with appropriate
performance criteria and QA procedures can provide Hg emissions data of
quality comparable to that produced by the Ontario Hydro Method. Data
supporting this conclusion are presented in the docket, EPA-HQ-OAR-
2007-0164.
    As we have done for Method 30A, for Method 30B emission tests and
RATAs performed prior to January 1, 2009, we are allowing either: (1) A
12-point traverse for sulfur dioxide (SO2) to be substituted
for a 12-point Hg traverse for the stratification testing used to
determine the number and location of the reference method sampling
points, or (2) use of the alternate three-point traverse line (0.4,
1.2, and 2.0 meters from the stack wall) as specified in section
<IP_ADDRESS> of Performance Specification 2 (40 CFR part 60, appendix B). We
also intend to extend this temporary deferral of mercury stratification
testing to application of the Ontario Hydro Method and Method 29. EPA
believes this deferral is reasonable because Hg monitoring data
reported to EPA in 2009 will not be used in the trading of Hg
allowances, as allowance accounting under the CAMR does not begin until
2010.
    This direct final rule also amends Performance Specification 12A of
appendix B to part 60 by adding Methods 30A and 30B to the list of
reference methods acceptable for relative accuracy testing of Hg
emissions monitoring systems. Once this direct final rule becomes
effective, the reference methods acceptable for Hg measurement in
Performance Specification 12A will include Methods 29, 30A, 30B, and
ASTM D6784-02.
    With today's action, EPA is taking the opportunity to include
several considered revisions to the Hg emission monitoring provisions
of 40 CFR parts 72 and 75 as described in detail below. EPA is
including these revisions in this direct final rule because we believe
that they will facilitate implementation of the Hg monitoring under
CAMR.
    First, Sec.  75.81(a) is being revised to confirm that the Hg CEMS
and sorbent trap monitoring systems required under subpart I of part 75
are to measure the total vapor phase mass concentration of Hg in the
flue gas, including both the elemental and oxidized forms of Hg,
expressed in units of micrograms per standard cubic meter ([mu]g/scm).
Although it is generally understood that total vapor phase Hg is the
regulated pollutant under CAMR, it recently was brought to EPA's
attention that subpart I of part 75 does not explicitly state that Hg
monitoring systems only need to measure total vapor phase Hg. The
amended language in Sec.  75.81(a) clarifies this.
    Second, paragraph (i) in Sec.  75.15 is being revised and a new
paragraph (d)(2)(ix) is being added to Sec.  75.20, to codify the rules
for using optional non-redundant (``cold'') backup Hg monitoring
systems and like-kind replacement Hg analyzers, when the primary Hg
monitoring system is unable to provide quality-assured data. For the
other types of monitoring systems required by part 75, these monitoring
options have been in place since May 1999 (see 64 FR 28597, May 26,
1999). Today's action simply extends these provisions to Hg monitoring
systems. Through the years, the regulated community has found these
backup monitoring options to be beneficial, in that they minimize the
use of missing data substitution procedures during outages of the
primary monitoring system.
    In particular, Sec.  75.20(d)(2)(ix) specifies that a non-redundant
backup Hg monitoring system can either be a Hg CEMS or a sorbent trap
monitoring system. The non-redundant backup Hg

monitoring system must be initially certified at each unit or stack
location where it will be used, in accordance with Sec.
75.20(d)(2)(i). For a non-redundant backup Hg CEMS, all of the initial
certification tests specified in Sec.  75.20(c)(1) are required, except
for the 7-day calibration error test. However, for ongoing quality
assurance (QA), a RATA is required only once every two years (8
calendar quarters), as specified in Sec.  75.20(d)(2)(vi). For a non-
redundant backup sorbent trap monitoring system, a RATA is required for
initial certification, and once every two years thereafter for ongoing
QA.
    When a certified non-redundant backup Hg CEMS or a like-kind
replacement Hg analyzer is brought into service, a three-point
linearity check with elemental Hg standards and a single-point system
integrity check will be required. Alternatively, a three-level system
integrity check may be performed instead of these two tests. When a
certified non-redundant backup sorbent trap monitoring system is
brought into service, only the routine sampling and QA procedures of
Sec.  75.15 and appendix K of part 75 will be required.
    Each non-redundant backup Hg monitoring system and each like-kind
replacement Hg analyzer will be subject to the applicable ongoing QA
requirements, restrictions and conditions specified in Sec.
75.20(d)(2). For certified non-redundant backup Hg CEMS and like-kind
replacement Hg analyzers, the weekly system integrity checks described
in section 2.6 of appendix B of 40 CFR part 75 will also be required as
long as the system or analyzer remains in service, unless the daily
calibration error tests of the analyzer are done using NIST-traceable
oxidized Hg standards.
    Third, a new paragraph (k) is being added to Sec.  75.15 that: (1)
Clarifies that, when the RATA of an appendix K sorbent trap monitoring
system is performed, the type of sorbent material used in the appendix
K sorbent traps must be the same as that used for daily operation of
the appendix K monitoring system, and (2) allows the appendix K traps
used during RATA testing to be smaller than the traps used for daily
operation of the appendix K monitoring system. This change will be
particularly advantageous at very low Hg concentrations as it will
facilitate shorter RATA test run times. Parallel changes are being made
to section 6.5.7 of appendix A of part 75 to be consistent with the
provisions of Sec.  75.15(k). Section 6.5.7 currently requires the
appendix K sorbent traps used for the RATA to be the same size as the
traps used for daily operation of the appendix K monitoring system.
    Fourth, today's action revises a number of sections of part 75,
appendix K, pertaining to the use of sorbent trap monitoring systems.
EPA is withdrawing the requirement to use the percentage recovery of
the elemental Hg spike in section 3 of each sorbent trap to adjust or
``normalize'' the Hg mass collected in sections 1 and 2 of the trap.
The requirement to spike the third section of each trap is being
retained and data from each pair of traps must still be invalidated if
either or both spike recovery percentages fall outside the acceptable
limits;\1\ however, the results of the spike recoveries will no longer
be used to adjust the Hg mass collected in the first two sections of
the traps. EPA is making this rule change based on an analysis of
recent spike recovery data from long-term appendix K field
demonstrations. Although the vast majority of the spike recoveries in
these studies have been within the currently acceptable limits of 75 to
125 percent, the requirement to normalize based on spike recovery could
affect data precision. For a given pair of traps, if one spike recovery
was high (e.g., 110 percent) and the other one low (e.g., 90 percent),
normalization of the Hg mass collected in the first two trap sections
using third section spike recoveries could make it difficult for a pair
of sorbent traps to meet the relative deviation (RD) specifications in
appendix K. In the example cited, normalization of the data would cause
the Hg concentrations measured by the traps to be adjusted by 10
percent in opposite directions, i.e., one upward and one downward.
Thus, two Hg concentrations that may have been in close agreement
without normalization now might not be able to meet the RD
specifications. In view of this, EPA has concluded that evaluating the
spike recovery data on a pass/fail basis instead of using the percent
recovery values to adjust the emissions data is more technically sound
and is also consistent with the way in which the results of daily and
quarterly QA assessments of CEMS are interpreted.
---------------------------------------------------------------------------

    \1\ On August 22, 2006, EPA proposed to amend Appendix K to
allow the data from a pair of sorbent traps to be validated in cases
where the third section spike recovery from only one of the traps
meets the percent recovery specifications (see 71 FR 49275). EPA
proposed to allow the results from the trap that meets the
specifications to be used for reporting, provided that a single trap
adjustment factor (STAF) of 1.222 is applied. EPA is evaluating the
comments received on this proposal and expects to publish the final
rule in the summer of 2007.
---------------------------------------------------------------------------

    Regarding the range of acceptable third section spike recoveries,
EPA is not changing the 75 to 125 percent acceptance criteria. As
previously noted, early field experience with appendix K monitoring
systems has demonstrated that spike recoveries within this range are
achievable. However, recent appendix K data indicate that more
stringent acceptance criteria may be justifiable. It appears that there
has been a marked improvement in third section spike recovery
percentages. Recoveries in the range from 85 to 115 percent are
consistently being achieved. If this trend continues, EPA may propose
to tighten the spike recovery acceptance criteria in a future
rulemaking. Toward that end, EPA will continue to collect and evaluate
third section spike recovery data from appendix K monitoring systems in
the months ahead.
    To effect these changes to appendix K, section 11.5 is being
removed and reserved; section 10.4 is being revised; Equations K-6 and
K-7 are being redesignated as Equations K-5 and K-6, respectively; and
the definition of ``M*'' in redesignated Equation K-5 is being revised.
    EPA is also revising appendix K to allow the owner or operator to
use other types of gas flow meters besides the conventional dry gas
meter (DGM) to quantify sample gas volume. Since the publication of
appendix K (see 70 FR 28695, May 18, 2005), numerous requests have been
received from the regulated community to allow this flexibility. In
response to these requests, EPA initiated an investigation of the
feasibility of replacing the DGM in a sorbent trap monitoring system
with a thermal mass flow meter. As a result of its investigation, EPA
has concluded that a properly calibrated thermal mass flow meter can be
at least as accurate as a DGM. The mass flow meter is also a more
modern technology than the DGM; since it has no moving parts, it may be
more reliable than a DGM for continuous duty.
    Having found one type of gas flow meter that can measure as
accurately as a DGM, EPA is persuaded that there may be other
commercially available gas flow meter technologies that are equally
capable and may be suitable for appendix K applications. Accordingly,
EPA has decided that a performance-based approach, rather than a
prescriptive one, is more appropriate for appendix K gas flow meters.
Today's action allows the use of any type of gas flow meter that is
capable of accurately measuring gas volumes to within 2 percent.
    Section <IP_ADDRESS> of appendix K now requires the manufacturer of the
gas flow meter to perform all necessary set-

up, testing, programming, etc. of the meter and to provide any
necessary instructions so that for the particular field application,
the meter will give an accurate readout of dry gas volume in units of
standard cubic meters. Then, prior to its initial use, the flow meter
must be calibrated at a minimum of three settings covering the expected
range of sample flow rates for the appendix K system. The initial
calibration may be performed either by the manufacturer or by the end
user. The calibration of the gas flow meter must be checked quarterly
thereafter, at an intermediate flow rate. For mass flow meters, the
initial three-point calibration must be performed by using either a
compressed gas mixture containing CO2, O2, and
N2 in proportions representative of the stack gas
composition or by using the actual stack gas. However, when the initial
calibration is done with a compressed gas mixture, the mass flow meter
may not be used until an additional on-site calibration check of the
flow meter at an intermediate flow rate is performed and passed, using
the actual stack gas.
    To calibrate the gas flow meter, the owner or operator may either
follow the basic procedures in section 10.3 or section 16 of Method 5
in appendix A-3 of part 60 for calibration of dry gas meters, or
alternatively, may temporarily install a reference gas flow meter
(RGFM) at the discharge of the appendix K monitoring system while the
monitoring system is in operation and make concurrent measurements of
dry stack gas volume with the RGFM and the appendix K gas flow meter.
If the latter option is chosen, the RGFM may either be a gas flow
metering device that has been calibrated according to section 10.3.1 or
section 16 of Method 5 or a NIST-traceable volumetric calibration
device with an accuracy of 1 percent. Note that this
alternative calibration technique allows required QA checks to be
performed with little or no disruption of the operation of the sorbent
trap monitoring system.
    Regardless of which calibration approach is used, a calibration
factor, Yi, must be obtained at each tested flow rate, where
Yi is the ratio of the volume measured by the reference
meter to the volume measured by the flow meter being calibrated. For
the initial three-point calibration, the three Yi values
must be averaged, and each individual Yi must be within
 0.02 of the average value. The average value, Y, must then
be used to correct the gas volumes measured by the gas flow meter. For
single-level calibration checks (e.g., the quarterly checks performed
for routine QA), the Yi value obtained at the tested flow
rate must be compared with the current value of Y. If Yi
differs from Y by more than 5 percent, a full three-point recalibration
is then required to determine a new Y value.
    In this direct final action, the majority of the revised rule
provisions pertaining to gas flow meters can be found in sections 5.1.5
and 9.2 of appendix K. Minor revisions to sections 7.2.3 and 7.2.5,
Figure K-1, and Table K-1 are being made to be consistent with the
changes to sections 5.1.5 and 9.2. In several other places throughout
part 75 and in the definition of ``Sorbent trap monitoring system'' in
part 72, the term ``dry gas meter,'' when used in reference to a
sorbent trap monitoring system, is being replaced with the more general
term ``gas flow meter.'' Revisions to section 1.5.2 of appendix B of
part 75 will require the gas flow meter calibration procedures and
protocols for periodic recalibration of reference gas flow meters to be
included in the QA plan for the affected unit.
    This direct final action, which approves the use of two optional
methods (Methods 30A and 30B) for determining total vapor phase Hg
emissions from stationary sources, is being taken in response to
numerous public comments concerning the desirability of allowing the
use of these types of methods to comply with the Hg emission monitoring
requirements of the CAMR for electric utility steam generating units.
In the May 18, 2005 final rule (70 FR 28636), we summarized the public
comments that we received regarding the use of an instrumental method
as an alternative to the Ontario Hydro Method specified in the proposed
CAMR. As noted earlier in this preamble, the commenters primarily
objected to the required use of the Ontario Hydro Method as the
reference method for the RATAs of Hg monitoring systems and expressed
concern about the complexities in the method and the amount of time
that is required to perform the testing and to receive the results.
Commenters pointed out that it could take days to complete the testing
and weeks to receive the results from a laboratory. Commenters claimed
that for the cap and trade program proposed under CAMR, these delays
could lead to significant implementation problems with respect to the
timely reporting of emissions data. Further, if a RATA should be failed
or invalidated (e.g., if fewer than nine test runs meet the relative
deviation criterion for the paired Ontario Hydro trains), data from the
Hg monitoring system would be invalidated from the hour of the failed
or invalidated test until the hour of completion of a successful RATA.
Conservatively high substitute data values would have to be reported
during that entire time period. In our response to those comments in
the final CAMR rule, we stated that the alternative use of an
instrumental method for the required RATAs of Hg monitoring systems and
sorbent trap monitoring systems is allowed by the final rule but is
subject to approval by the Administrator. We also stated our commitment
to propose and promulgate a Hg instrumental reference method once
sufficient supporting field test data become available. We further
stated that ``A Hg instrumental reference method for RATA testing is
vastly preferable to the Ontario Hydro Method and will greatly
facilitate the implementation of a Hg cap-and-trade program.''
    Since promulgation of CAMR, we have continued to communicate with
stakeholders interested in the Hg monitoring requirements of the rule,
and we have come to more clearly understand that it is of great
interest to the affected entities to have additional reference method
options available for relative accuracy testing of installed Hg
monitoring systems as soon as possible. Accordingly, at the end of
2005, we began developing an instrumental test method for Hg and
solicited feedback from the stakeholders on a working draft of the
method (referred to as PRE-009 at http://www.epa.gov/ttn/emc/prelim.html
). More recently, we have been developing a viable sorbent

trap reference method. These efforts have resulted in Methods 30A and
30B.
    The general beneficial impacts of this direct final rule to approve
the two optional Hg test methods and amend targeted portions of 40 CFR
parts 72 and 75 include: Allowing affected sources to choose the use of
an alternative to the Ontario Hydro Method without the administrative
burden of applying for Administrator approval on a case-by-case basis;
providing the availability of real-time RATA results (Method 30A);
reducing the overall RATA testing times; reducing costs relative to the
Ontario Hydro Method; and providing additional flexibility in appendix
K sorbent trap monitoring and backup monitoring approaches. The two
optional methods being approved by this direct final rule are
considered to be comparable to the Ontario Hydro Method in terms of the
quality of the results produced. Over the last year, EPA has
collaborated with EPRI and some of its members in a number of field
test programs that have confirmed that the instrumental reference
method approved/established in this notice will provide data comparable
to or better

than that of the ``Ontario Hydro Method.''
    Assuming we do not receive adverse comment on this direct final
rulemaking and Methods 30A and 30B become final, we plan to post
information relevant to Method 30A and 30B applications and equipment
advances on EPA's Web site at http://www.epa.gov/airmarkets.

VII. Statutory and Executive Order Reviews

A. Executive Order 12866: Regulatory Planning and Review

    This action is not a ``significant regulatory action'' under the
terms of Executive Order (EO) 12866 (58 FR 51735, October 4, 1993) and
is therefore not subject to review under the EO.

B. Paperwork Reduction Act

    This action does not impose an information collection burden under
the provisions of the Paperwork Reduction Act, 44 U.S.C. 3501 et seq.
Burden means the total time, effort, or financial resources expended by
persons to generate, maintain, retain, or disclose or provide
information to or for a Federal agency. This includes the time needed
to review instructions; develop, acquire, install, and utilize
technology and systems for the purposes of collecting, validating, and
verifying information, processing and maintaining information, and
disclosing and providing information; adjust the existing ways to
comply with any previously applicable instructions and requirements;
train personnel to be able to respond to a collection of information;
search data sources; complete and review the collection of information;
and transmit or otherwise disclose the information.
    An agency may not conduct or sponsor, and a person is not required
to respond to a collection of information, unless it displays a
currently valid OMB control number. The OMB control numbers for EPA's
regulations in 40 CFR are listed in 40 CFR part 9.

C. Regulatory Flexibility Act

    The Regulatory Flexibility Act (RFA) generally requires an agency
to prepare a regulatory flexibility analysis of any rule subject to
notice and comment rulemaking requirements under the Administrative
Procedure Act or any other statute unless the agency certifies that the
rule will not have a significant economic impact on a substantial
number of small entities. Small entities include small businesses,
small organizations, and small governmental jurisdictions.
    For purposes of assessing the impacts of today's rule on small
entities, small entity is defined as: (1) A small business whose parent
company has fewer than 100 or 1,000 employees, or fewer than 4 billion
kilowatt-hr per year of electricity usage, depending on the size
definition for the affected North American Industry Classification
System code; (2) a small governmental jurisdiction that is a government
of a city, county, town, school district or special district with a
population of less than 50,000; and (3) a small organization that is
any not-for-profit enterprise which is independently owned and operated
and is not dominant in its field.
    After considering the economic impacts of today's direct final rule
on small entities, I certify that this action will not have a
significant economic impact on a substantial number of small entities.
This direct final rule will not impose any requirements on small
entities because it does not impose any additional regulatory
requirements, but rather provides clarification and additional
regulatory flexibilty.

D. Unfunded Mandates Reform Act

    Title II of the Unfunded Mandates Reform Act of 1995 (UMRA), Pub.
L. 104-4, establishes requirements for Federal agencies to assess the
effects of their regulatory actions on State, local, and tribal
governments and the private sector. Under section 202 of the UMRA, EPA
generally must prepare a written statement, including a cost-benefit
analysis, for proposed and final rules with ``Federal mandates'' that
may result in expenditures to State, local, and tribal governments, in
the aggregate, or to the private sector, of $100 million or more in any
one year. Before promulgating an EPA rule for which a written statement
is needed, section 205 of the UMRA generally requires EPA to identify
and consider a reasonable number of regulatory alternatives and adopt
the least costly, most cost-effective or least burdensome alternative
that achieves the objectives of the rule. The provisions of section 205
do not apply when they are inconsistent with applicable law. Moreover,
section 205 allows EPA to adopt an alternative other than the least
costly, most cost-effective, or least burdensome alternative if the
Administrator publishes with the final rule an explanation why that
alternative was not adopted. Before EPA establishes any regulatory
requirements that may significantly or uniquely affect small
governments, including tribal governments, it must have developed under
section 203 of the UMRA a small government agency plan. The plan must
provide for notifying potentially affected small governments, enabling
officials of affected small governments to have meaningful and timely
input in the development of EPA regulatory proposals with significant
Federal intergovernmental mandates, and informing, educating, and
advising small governments on compliance with the regulatory
requirements.
    EPA has determined that this direct final rule does not contain a
Federal mandate that may result in expenditures of $100 million or more
for State, local, and tribal governments in the aggregate, or to the
private sector in any 1 year, nor does this rule significantly or
uniquely impact small governments, because it contains no requirements
that impose new obligations upon them. Thus, this direct final rule is
not subject to the requirements of sections 202 and 205 of the UMRA.

E. Executive Order 13132: Federalism

    Executive Order 13132, entitled ``Federalism'' (64 FR 43255, August
10, 1999), requires EPA to develop an accountable process to ensure
``meaningful and timely input by State and local officials in the
development of regulatory policies that have federalism implications.''
``Policies that have federalism implications'' is defined in the
Executive Order to include regulations that have ``substantial direct
effects on the States, on the relationship between the national
government and the States, or on the distribution of power and
responsibilities among the various levels of government.''
    This direct final rule does not have federalism implications. It
will not have substantial direct effects on the States, on the
relationship between the national government and the States, or on the
distribution of power and responsibilities among the various levels of
government, as specified in Executive Order 13132. The use of these
methods is optional on the part of the regulated entities listed. Thus,
Executive Order 13132 does not apply to this direct final rule.

F. Executive Order 13175: Consultation and Coordination With Indian
Tribal Governments

    Executive Order 13175, entitled ``Consultation and Coordination
with Indian Tribal Governments'' (65 FR 67249, November 9, 2000),
requires EPA to develop an accountable process to ensure ``meaningful
and timely input by tribal officials in the development of regulatory
policies that have tribal implications.'' This direct final rule does
not have tribal implications, as specified in Executive Order 13175. It
will not have substantial direct effects on tribal governments, on the

relationship between the Federal government and Indian tribes, or on
the distribution of power and responsibilities between the Federal
government and Indian tribes. Thus, Executive Order 13175 does not
apply to this final rule.

G. Executive Order 13045: Protection of Children From Environmental
Health and Safety Risks

    Executive Order 13045: ``Protection of Children from Environmental
Health Risks and Safety Risks'' (62 FR 19885, April 23, 1997) applies
to any rule that: (1) Is determined to be ``economically significant''
as defined under Executive Order 12866, and (2) concerns an
environmental health or safety risk that EPA has reason to believe may
have a disproportionate effect on children. If the regulatory action
meets both criteria, the Agency must evaluate the environmental health
or safety effects of the planned rule on children, and explain why the
planned regulation is preferable to other potentially effective and
reasonably feasible alternatives considered by the Agency. EPA
interprets Executive Order 13045 as applying only to those regulatory
actions that are based on health or safety risks, such that the
analysis required under section 5-501 of the Order has the potential to
influence the regulation. This rule is not subject to Executive Order
13045 because it does not establish an environmental standard intended
to mitigate health or safety risks.

H. Executive Order 13211: Actions That Significantly Affect Energy
Supply, Distribution, or Use

    This rule is not subject to Executive Order 13211, ``Actions
Concerning Regulations That Significantly Affect Energy Supply,
Distribution, or Use'' (66 FR 28355, May 22, 2001) because it is not a
significant regulatory action under Executive Order 12866.

I. National Technology Transfer Advancement Act

    Section 12(d) of the National Technology Transfer and Advancement
Act of 1995 (NTTAA), Public Law No. 104-113, section 12(d) (15 U.S.C.
272 note) directs EPA to use voluntary consensus standards in its
regulatory activities unless to do so would be inconsistent with
applicable law or otherwise impractical. Voluntary consensus standards
are technical standards (e.g., materials specifications, test methods,
sampling procedures, and business practices) that are developed or
adopted by voluntary consensus standards bodies. The NTTAA directs EPA
to provide Congress, through OMB, explanations when the Agency decides
not to use available and applicable voluntary consensus standards. This
rulemaking involves technical standards. Consistent with the NTTAA, EPA
in a previous related rulemaking (70 FR 28606, May 18, 2005) identified
an acceptable VCS for measuring Hg emissions. The standard ASTM D6784-
02, Standard Test Method for Elemental, Oxidized, Particle-Bound and
Total Mercury Gas Generated from Coal-Fired Stationary sources (Ontario
Hydro Method) was cited in that final rule for measuring Hg emissions.
After today's action becomes effective, the Ontario Hydro Method will
remain an acceptable method for measuring Hg emissions.

J. Executive Order 12898: Federal Actions To Address Environmental
Justice in Minority Populations and Low-Income Populations

    Executive Order 12898 (59 FR 7629 (Feb. 16, 1994)) establishes
federal executive policy on environmental justice. Its main provision
directs federal agencies, to the greatest extent practicable and
permitted by law, to make environmental justice part of their mission
by identifying and addressing, as appropriate, disproportionately high
and adverse human health or environmental effects of their programs,
policies, and activities on minority populations and low-income
populations in the United States.
    EPA has determined that this direct final rule will not have
disproportionately high and adverse human health or environmental
effects on minority or low-income populations because it does not
affect the level of protection provided to human health or the
environment. This direct final rule does not affect or relax the
control measures on sources impacted by this rule and therefore will
not cause emissions increases from these sources.

K. Congressional Review Act

    The Congressional Review Act, 5 U.S.C. 801 et seq., as added by the
Small Business Regulatory Enforcement Fairness Act of 1996, generally
provides that before a rule may take effect, the Agency promulgating
the rule must submit a rule report, which includes a copy of the rule,
to each House of the Congress and to the Comptroller General of the
United States. EPA will submit a report containing this rule and other
required information to the U.S. Senate, the U.S. House of
Representatives, and the Comptroller General of the United States prior
to publication of the rule in the Federal Register. A major rule cannot
take effect until 60 days after it is published in the Federal
Register. This action is not a ``major rule'' as defined by 5 U.S.C.
804(2). This rule will be effective on November 6, 2007.

List of Subjects

40 CFR Part 60

    Environmental protection, Administrative practice and procedures,
Air pollution control, Continuous emission monitors, Electric
utilities, Mercury, Test methods and procedures.

40 CFR Part 72

    Environmental protection, Administrative practice and procedures,
Air pollution control, Continuous emission monitors, Electric
utilities, Mercury, Test methods and procedures.

40 CFR Part 75

    Environmental protection, Administrative practice and procedures,
Air pollution control, Continuous emission monitors, Electric
utilities, Mercury, Test methods and procedures.

    Dated: August 17, 2007.
Stephen L. Johnson,
Administrator.

0
For the reasons set out in the preamble, title 40, chapter I, parts 60,
72, and 75 of the Code of Federal Regulations are amended as follows:

PART 60--STANDARDS OF PERFORMANCE FOR NEW STATIONARY SOURCES

0
1. The authority citation for part 60 continues to read as follows:

    Authority: 42 U.S.C. 7401-7601.

Appendix A-8 [Amended]

0
2. Amend Appendix A-8 by revising the heading and adding in numerical
order Methods 30A and 30B to read as follows:

APPENDIX A-8 TO PART 60--TEST METHODS 26 THROUGH 30B

* * * * *

Method 30A--Determination of Total Vapor Phase Mercury Emissions From
Stationary Sources (Instrumental Analyzer Procedure)

1.0 Scope and Application

What Is Method 30A?

    Method 30A is a procedure for measuring total vapor phase
mercury (Hg) emissions from stationary sources using an instrumental
analyzer. This method is particularly appropriate for performing
emissions testing and for conducting relative accuracy test audits
(RATAs) of mercury continuous emissions monitoring systems (Hg CEMS)
and sorbent trap monitoring systems at coal-fired combustion
sources. Quality assurance and quality control

requirements are included to assure that you, the tester, collect
data of known and acceptable quality for each testing site. This
method does not completely describe all equipment, supplies, and
sampling procedures and analytical procedures you will need but
refers to other test methods for some of the details. Therefore, to
obtain reliable results, you should also have a thorough knowledge
of these additional methods which are also found in appendices A-1
and A-3 to this part:
    (a) Method 1--Sample and Velocity Traverses for Stationary
Sources.
    (b) Method 4--Determination of Moisture Content in Stack Gases.
    1.1 Analytes. What does this method determine? This method is
designed to measure the mass concentration of total vapor phase Hg
in flue gas, which represents the sum of elemental Hg (Hg\0\) and
oxidized forms of Hg (Hg+\2\), in mass concentration
units of micrograms per cubic meter ([mu]g/m\3\).

------------------------------------------------------------------------
              Analyte                   CAS No.          Sensitivity
------------------------------------------------------------------------
Elemental Hg (Hg\0\)..............       7439-97-6  Typically < 2% of
                                                     Calibration Span.
Oxidized Hg (Hg+\2\)..............  ..............  (Same).
------------------------------------------------------------------------

    1.2 Applicability. When is this method required? Method 30A is
offered as a reference method for emission testing and for RATAs of
Hg CEMS and sorbent trap monitoring systems at coal-fired boilers.
Method 30A may also be specified for other source categories in the
future, either by New Source Performance Standards (NSPS), National
Emission Standards for Hazardous Air Pollutants (NESHAP), emissions
trading programs, State Implementation Plans (SIP), or operating
permits that require measurement of Hg concentrations in stationary
source emissions to determine compliance with an applicable emission
standard or limit, or to conduct RATAs of Hg CEMS and sorbent trap
monitoring systems.
    1.3 Data Quality Objectives (DQO). How good must my collected
data be? Method 30A has been designed to provide data of high and
known quality for Hg emission testing and for relative accuracy
testing of Hg monitoring systems including Hg CEMS and sorbent trap
monitoring systems. In these and other applications, the principle
objective is to ensure the accuracy of the data at the actual
emission levels encountered. To meet this objective, calibration
standards prepared according to an EPA traceability protocol must be
used and measurement system performance tests are required.

2.0 Summary of Method

    In this method, a sample of the effluent gas is continuously
extracted and conveyed to an analyzer capable of measuring the total
vapor phase Hg concentration. Elemental and oxidized mercury (i.e.,
Hg\0\ and Hg+\2\) may be measured separately or
simultaneously but, for purposes of this method, total vapor phase
Hg is the sum of Hg\0\ and Hg+\2\. You must meet the
performance requirements of this method (i.e., system calibration,
interference testing, dynamic spiking, and system integrity/drift
checks) to validate your data. The dynamic spiking requirement is
deferred until January 1, 2009.

3.0 Definitions

    3.1 Calibration Curve means the relationship between an
analyzer's response to the injection of a series of calibration
gases and the actual concentrations of those gases.
    3.2 Calibration Gas means a gas standard containing Hg\0\ or
HgCl2 at a known concentration that is produced and
certified in accordance with an EPA traceability protocol for
certification of Hg calibration standards.
    3.2.1 Zero Gas means a calibration gas with a concentration that
is below the level detectable by the measurement system.
    3.2.2 Low-Level Gas means a calibration gas with a concentration
that is 10 to 30 percent of the calibration span.
    3.2.3 Mid-Level Gas means a calibration gas with a concentration
that is 40 to 60 percent of the calibration span.
    3.2.4 High-Level Gas means a calibration gas whose concentration
is equal to the calibration span.
    3.3 Converter means a device that reduces oxidized mercury
(Hg+\2\) to elemental mercury (Hg\0\).
    3.4 Calibration Span means the upper limit of valid instrument
response during sampling. To the extent practicable the measured
emissions are to be between 10 and 100 percent of the selected
calibration span (i.e., the measured emissions should be within the
calibrated range determined by the Low- and High-Level gas
standards). It is recommended that the calibration span be at least
twice the native concentration to accommodate the dynamic spiking
procedure.
    3.5 Centroidal Area means the central area that has the same
shape as the stack or duct cross section and is no greater than one
percent of the stack or duct total cross-sectional area.
    3.6 Data Recorder means the equipment that permanently records
the concentrations reported by the analyzer.
    3.7 Drift Check means the test to determine the difference
between the measurement system readings obtained in a post-run
system integrity check and the prior pre-run system integrity check
at a specific calibration gas concentration level (i.e., zero, mid-
level, or high-level).
    3.8 Dynamic Spiking means a procedure in which a known mass or
concentration of vapor phase HgCl2 is injected into the
probe sample gas stream at a known flow rate, in order to assess the
effects of the flue gas matrix on the accuracy of the measurement
system.
    3.9 Gas Analyzer means the equipment that detects the total
vapor phase Hg being measured and generates an output proportional
to its concentration.
    3.10 Interference Test means the test to detect analyzer
responses to compounds other than Hg, usually gases present in the
measured gas stream, that are not adequately accounted for in the
calibration procedure and may cause measurement bias.
    3.11 Measurement System means all of the equipment used to
determine the Hg concentration. The measurement system may generally
include the following major subsystems: sample acquisition,
Hg+2 to Hg0 converter, sample transport,
sample conditioning, flow control/gas manifold, gas analyzer, and
data recorder.
    3.12 Native Concentration means the total vapor phase Hg
concentration in the effluent gas stream.
    3.13 NIST means the National Institute of Standards and
Technology, located in Gaithersburg, Maryland.
    3.14 Response Time means the time it takes for the measurement
system, while operating normally at its target sample flow rate or
dilution ratio, to respond to a known step change in gas
concentration (from a low-level to a high-level gas) and to read
within 5 percent of the stable high-level gas response.
    3.15 Run means a series of gas samples taken successively from
the stack or duct. A test normally consists of a specific number of
runs.
    3.16 System Calibration Error means the difference between the
measured concentration of a low-, mid-, or high-level Hg\0\
calibration gas and the certified concentration of the gas when it
is introduced in system calibration mode.
    3.17 System Calibration Mode means introducing the calibration
gases into the measurement system at the probe, upstream of all
sample conditioning components.
    3.18 Test refers to the series of runs required by the
applicable regulation.

4.0 Interferences

    Interferences will vary among instruments and potential
instrument-specific spectral and matrix interferences must be
evaluated through the interference test and the dynamic spiking
tests.

5.0 Safety

What safety measures should I consider when using this method?

    This method may require you to work with hazardous materials and
in hazardous conditions. You are encouraged to establish safety
procedures before using the method. Among other precautions, you
should become familiar with the safety recommendations in the gas
analyzer user's manual. Occupational Safety and Health
Administration (OSHA) regulations concerning use of compressed gas
cylinders and noxious gases may apply.

6.0 Equipment and Supplies

    6.1 What do I need for the measurement system? This method is
intended to be applicable to multiple instrumental technologies. You
may use any equipment and supplies that meet the following
specifications.
    6.1.1 All wetted sampling system components, including probe
components prior to the point at which the calibration gas is
introduced, must be chemically inert to all Hg species. Materials
such as perfluoroalkoxy (PFA) Teflon\TM\, quartz, treated stainless
steel (SS) are examples of such materials. [Note: These materials of
construction are required because components prior to the
calibration gas injection point are not included in the system
calibration error, system integrity, and interference tests.]
    6.1.2 The interference, system calibration error, system
integrity, drift and dynamic spiking test criteria must all be met
by the system used.
    6.1.3 The system must be capable of measuring and controlling
sample flow rate.
    6.1.4 All system components prior to the Hg+\2\ to
Hg\0\ converter must be maintained at a sample temperature above the
acid gas dew point.
    6.2 Measurement System Components. Figure 30A-1 in Section 17.0
is an example schematic of a Method 30A measurement system.
    6.2.1 Sample Probe. The probe must be made of the appropriate
materials as noted in Section 6.1.1, heated when necessary (see
Section 6.1.4), configured with ports for introduction of
calibration and spiking gases, and of sufficient length to traverse
all of the sample points.
    6.2.2 Filter or Other Particulate Removal Device. The filter or
other particulate removal device is considered to be a part of the
measurement system, must be made of appropriate materials as noted
in Section 6.1.1, and must be included in all system tests.
    6.2.3 Sample Line. The sample line that connects the probe to
the converter, conditioning system and analyzer must be made of
appropriate materials as noted in Section 6.1.1.
    6.2.4 Conditioning Equipment. For dry basis measurements, a
condenser, dryer or other suitable device is required to remove
moisture continuously from the sample gas. Any equipment needed to
heat the probe, or sample line to avoid condensation prior to the
moisture removal component is also required. For wet basis systems,
you must keep the sample above its dew point either by: (1) Heating
the sample line and all sample transport components up to the inlet
of the analyzer (and, for hot-wet extractive systems, also heating
the analyzer) or (2) by diluting the sample prior to analysis using
a dilution probe system. The components required to do either of the
above are considered to be conditioning equipment.
    6.2.5 Sampling Pump. A pump is needed to push or pull the sample
gas through the system at a flow rate sufficient to minimize the
response time of the measurement system. If a mechanical sample pump
is used and its surfaces are in contact with the sample gas prior to
detection, the pump must be leak free and must be constructed of a
material that is non-reactive to the gas being sampled (see Section
6.1.1). For dilution-type measurement systems, an ejector pump
(eductor) may be used to create a sufficient vacuum that sample gas
will be drawn through a critical orifice at a constant rate. The
ejector pump may be constructed of any material that is non-reactive
to the gas being sampled.
    6.2.6 Calibration Gas System(s). One or more systems may be
needed to introduce calibration gases into the measurement system. A
system should be able to flood the sampling probe sufficiently to
prevent entry of gas from the effluent stream.
    6.2.7 Dynamic Spiking Port. For the purposes of the dynamic
spiking procedure described in Section 8.2.7, the measurement system
must be equipped with a port to allow introduction of the dynamic
spike gas stream with the sample gas stream, at a point as close as
possible to the inlet of the probe so as to ensure adequate mixing.
The same port used for system calibrations and calibration error
checks may be used for dynamic spiking purposes.
    6.2.8 Sample Gas Delivery. The sample line may feed directly to
a converter, to a by-pass valve (for speciating systems), or to a
sample manifold. All valve and/or manifold components must be made
of material that is non-reactive to the gas sampled and the
calibration gas, and must be configured to safely discharge any
excess gas.
    6.2.9 Hg Analyzer. An instrument is required that continuously
measures the total vapor phase Hg in the gas stream and meets the
applicable specifications in Section 13.0.
    6.2.10 Data Recorder. A recorder, such as a computerized data
acquisition and handling system (DAHS), digital recorder, strip
chart, or data logger, is required for recording measurement data.
    6.3 Moisture Measurement System. If correction of the measured
Hg emissions for moisture is required (see Section 8.5), either
Method 4 in appendix A-3 to this part or other moisture measurement
methods approved by the Administrator will be needed to measure
stack gas moisture content.

7.0 Reagents and Standards

    7.1 Calibration Gases. What calibration gases do I need? You
will need calibration gases of known concentrations of Hg\0\ and
HgCl2. Special reagents and equipment may be required to
prepare the HgCl\2\ gas standards (e.g., a NIST-traceable solution
of HgCl2 and a gas generator equipped with mass flow
controllers).
    The following calibration gas concentrations are required:
    7.1.1 High-Level Gas. Equal to the selected calibration span.
    7.1.2 Mid-Level Gas. 40 to 60 percent of the calibration span.
    7.1.3 Low-Level Gas. 10 to 30 percent of the calibration span.
    7.1.4 Zero Gas. No detectable Hg.
    7.1.5 Dynamic Spike Gas. The exact concentration of the
HgCl2 calibration gas used to perform the pre-test
dynamic spiking procedure described in Section 8.2.7 depends on the
native Hg concentration in the stack The spike gas must produce a
spiked sample concentration above the native concentration, as
specified in Section <IP_ADDRESS>.2.
    7.2 Interference Test. What reagents do I need for the
interference test? Use the appropriate test gases listed in Table
30A-3 in Section 17.0 (i.e., the potential interferents for the
source to be tested, as identified by the instrument manufacturer)
to conduct the interference check. These gases need not be of
protocol gas quality.

8.0 Sample Collection

Emission Test Procedure

    Figure 30A-2 in Section 17.0 presents an overview of the test
procedures required by this method. Since you may choose different
options to comply with certain performance criteria, you must
identify the specific options and associated frequencies you select
and document your results in regard to the performance criteria.
    8.1 Sample Point Selection. What sampling site and sampling
points do I select?
    8.1.1 When this method is used solely for Hg emission testing
(e.g., to determine compliance with an emission standard or limit),
use twelve sampling points located according to Table 1-1 or Table
1-2 of Method 1 in appendix A-1 to this part. Alternatively, you may
conduct a stratification test as described in Section 8.1.3 to
determine the number and location of the sampling points.
    8.1.2 When this method is used for relative accuracy testing of
a Hg CEMS or sorbent trap monitoring system, follow the sampling
site selection and sampling point layout procedures for gas monitor
RATA testing described in the appropriate performance specification
or applicable regulation (e.g., Performance Specification 2, section
8.1.3 of appendix B to this part or section 6.5.6 of appendix A to
part 75 of this chapter), with one exception. If you elect to
perform stratification testing as part of the sampling point
selection process, perform the testing in accordance with Section
8.1.3 of this method (see also ``Summary Table of QA/QC
Requirements'' in Section 9.0).
    8.1.3 Determination of Stratification. If you elect to perform
stratification testing as part of the sampling point selection
process and the test results show your effluent gas stream to be
unstratified or minimally stratified, you may be allowed to sample
at fewer points or at different points than would otherwise be
required.
    <IP_ADDRESS> Test Procedure. To test for stratification, use a probe
of appropriate length to measure the total vapor phase Hg
concentration at twelve traverse points located according to Table
1-1 or Table 1-2 of Method 1 in appendix A-1 to this part.
Alternatively, for a sampling location where stratification is
expected (e.g., after a wet scrubber or at a point where dissimilar
gas streams are combined together), if a 12-point Hg stratification
test has been previously performed at that location and the results
of the test showed the location to be minimally stratified or
unstratified according to the criteria in section <IP_ADDRESS>, you may
perform an abbreviated 3-point or 6-point Hg stratification test at
the points specified in

section <IP_ADDRESS>(a) of appendix A to part 75 of this chapter in lieu
of performing the 12-point test. Sample for a minimum of twice the
system response time (see Section 8.2.6) at each traverse point.
Calculate the individual point and mean Hg concentrations.
    <IP_ADDRESS> Acceptance Criteria and Sampling Point Location.
    <IP_ADDRESS>.1 If the Hg concentration at each traverse point differs
from the mean concentration for all traverse points by no more than:
(a) 5 percent of the mean concentration; or (b) 0.2 [mu]g/m\3\ (whichever is less restrictive), the gas stream
is considered to be unstratified and you may collect samples from a
single point that most closely matches the mean.
    <IP_ADDRESS>.2 If the 5 percent or 0.2 [mu]g/m\3\ criterion in
Section <IP_ADDRESS>.1 is not met, but the Hg concentration at each
traverse point differs from the mean concentration for all traverse
points by no more than: (a)10 percent of the mean; or
(b)0.5 [mu]g/m\3\ (whichever is less restrictive), the
gas stream is considered to be minimally stratified, and you may
take samples from three points, provided the points are located on
the measurement line exhibiting the highest average Hg concentration
during the stratification test. If the stack diameter (or equivalent
diameter, for a rectangular stack or duct) is greater than 2.4
meters (7.8 ft), locate the three sampling points at 0.4, 1.0, and
2.0 meters from the stack or duct wall. Alternatively, if a RATA
required by part 75 of this chapter is being conducted, you may
locate the three points at 4.4, 14.6, and 29.6 percent of the duct
diameter, in accordance with Method 1 in appendix A-1 to this part.
For stack or duct diameters of 2.4 meters (7.8 ft) or less, locate
the three sampling points at 16.7, 50.0, and 83.3 percent of the
measurement line.
    <IP_ADDRESS>.3 If the gas stream is found to be stratified because
the 10 percent or 0.5 [mu]g/m\3\ criterion in Section <IP_ADDRESS>.2 is
not met, then either locate three sampling points at 16.7, 50.0, and
83.3 percent of the measurement line that exhibited the highest
average Hg concentration during the stratification test, or locate
twelve traverse points for the test in accordance with Table 1-1 or
Table 1-2 of Method 1 in appendix A-1 to this part; or, if a RATA
required by part 75 of this chapter is being conducted, locate six
Method 1 points along the measurement line that exhibited the
highest average Hg concentration.
    <IP_ADDRESS> Temporal Variations. Temporal variations in the source
Hg concentration during a stratification test may complicate the
determination of stratification. If temporal variations are a
concern, you may use the following procedure to normalize the
stratification test data. A second Hg measurement system, i.e.,
either an installed Hg CEMS or another Method 30A system, is
required to perform this procedure. Position the sampling probe of
the second Hg measurement system at a fixed point in the stack or
duct, at least one meter from the stack or duct wall. Then, each
time that the Hg concentration is measured at one of the
stratification test points, make a concurrent measurement of Hg
concentration at the fixed point. Normalize the Hg concentration
measured at each traverse point, by multiplying it by the ratio of
CF,avg to CF, where CF is the
corresponding fixed-point Hg concentration measurement, and
CF,avg is the average of all of the fixed-point
measurements over the duration of the stratification test. Evaluate
the results of the stratification test according to section <IP_ADDRESS>,
using the normalized Hg concentrations.
    <IP_ADDRESS> Stratification Testing Exemption. Stratification testing
need not be performed at a test location where it would otherwise be
required to justify using fewer sample points or different sample
points, if the owner or operator documents that the Hg concentration
in the stack gas is expected to be 3 [mu]g/m\3\ or less at the time
of a Hg monitoring system RATA or an Hg emissions test. To
demonstrate that a particular test location qualifies for the
stratification testing exemption, representative Hg emissions data
must be collected just prior to the RATA or emissions test. At least
one hour of Hg concentration data is required for the demonstration.
The data used for the demonstration shall be recorded at process
operating conditions that closely approximate the operating
conditions that will exist during the RATA or emissions test. It is
recommended that collection of the demonstration data be integrated
with the on-site pretest procedures required by the reference method
being used for the RATA or emissions test (whether this method or
another approved Hg reference method is used). Quality-assured data
from an installed Hg monitoring system may also be used for the
demonstration. If a particular test location qualifies for the
stratification testing exemption, sampling shall be performed at
three points, as described in section <IP_ADDRESS>.2 of this method. The
owner or operator shall fully document the method used to collect
the demonstration data and shall keep this documentation on file
with the data from the associated RATA or Hg emissions test.
    <IP_ADDRESS> Interim Alternative Stratification Test Procedures. In
the time period between the effective date of this method and
January 1, 2009, you may follow one of the following two procedures.
Substitute a stratification test for sulfur dioxide (SO2)
for the Hg stratification test described in section <IP_ADDRESS>. If this
option is chosen, follow the test procedures in section <IP_ADDRESS> of
appendix A to part 75 of this chapter. Evaluate the test results and
determine the sampling point locations according to section <IP_ADDRESS>
of appendix A to part 75 of this chapter. If the sampling location
is found to be minimally stratified or unstratified for
SO2, it shall be considered minimally stratified or
unstratified for Hg. Alternatively, you may forgo stratification
testing, assume the gas stream is minimally stratified, and sample
at three points as described in section <IP_ADDRESS>.2 of this method.
    8.2 Initial Measurement System Performance Tests. What initial
performance criteria must my system meet before I begin sampling?
Before measuring emissions, perform the following procedures:
    (a) Interference Test;
    (b) Calibration Gas Verification;
    (c) Measurement System Preparation;
    (d) 3-Point System Calibration Error Test;
    (e) System Integrity Check;
    (f) Measurement System Response Time Test; and
    (g) Dynamic Spiking Test.
    8.2.1 Interference Test (Optional). Your measurement system
should be free of known interferences. It is recommended that you
conduct this interference test of your measurement system prior to
its initial use in the field to verify that the candidate test
instrument is free from inherent biases or interferences resulting
from common combustion emission constituents. If you have multiple
measurement systems with components of the same make and model
numbers, you need only perform this interference check on one system
and you may also rely on an interference test conducted by the
manufacturer on a system having components of the same make and
model(s) of the system that you use. The interference test procedure
is found in Section 8.6 of this method.
    8.2.2 Calibration Gas Verification. How must I verify the
concentrations of my calibration gases?
    <IP_ADDRESS> Cylinder Gas Standards. When cylinder gas standards are
used for Hg0, obtain a certificate from the gas
manufacturer and confirm that the documentation includes all
information required by an EPA traceability protocol (see Section
16). Confirm that the manufacturer certification is complete and
current. Ensure that the calibration gas certifications have not
expired.
    <IP_ADDRESS> Other Calibration Standards. All other calibration
standards for HgCl2 and Hg0, such as gas
generators, must meet the requirements of an EPA traceability
protocol (see Section 16), and the certification procedures must be
fully documented in the test report.
    <IP_ADDRESS> Calibration Span. Select the calibration span (i.e.,
high-level gas concentration) so that the measured source emissions
are 10 to 100 percent of the calibration span. This requirement is
waived for applications in which the Hg concentrations are
consistently below 1 [mu]g/m\3\; however, the calibration span for
these low-concentration applications shall not exceed 5 [mu]g/m\3\.
    8.2.3 Measurement System Preparation. How do I prepare my
measurement system for use? Assemble, prepare, and precondition the
measurement system according to your standard operating procedure.
Adjust the system to achieve the correct sampling rate or dilution
ratio (as applicable). Then, conduct a 3-point system calibration
error test using Hg0 as described in Section 8.2.4, an
initial system integrity check using HgCl2 and a zero gas
as described in Section 8.2.5, and a pre-test dynamic spiking test
as described in Section 8.2.7.
    8.2.4 System Calibration Error Test. Conduct a 3-point system
calibration error test before the first test run. Use Hg\0\
standards for this test. Introduce the low-, mid-, and high-level
calibration gases in any order, in system calibration mode, unless
you desire to determine the system response time during this test,
in which case, inject the gases such that the high-level injection

directly follows the low-level injection. For non-dilution systems,
you may adjust the system to maintain the correct flow rate at the
analyzer during the test, but you may not make adjustments for any
other purpose. For dilution systems, you must operate the
measurement system at the appropriate dilution ratio during all
system calibration error checks, and you may make only the
adjustments necessary to maintain the proper ratio. After each gas
injection, wait until a stable response has been obtained. Record
the analyzer's final, stable response to each calibration gas on a
form similar to Table 30A-1 in Section 17.0. For each calibration
gas, calculate the system calibration error using Equation 30A-1 in
Section 12.2. The calibration error specification in Section 13.1
must be met for the low-, mid-, and high-level gases. If the
calibration error specification is not met for all three gases, take
corrective action and repeat the test until an acceptable 3-point
calibration is achieved.
    8.2.5 System Integrity Check. Perform a two-point system
integrity check before the first test run. Use the zero gas and
either the mid- or high-level HgCl2 calibration gas for
the check, whichever one best represents the total vapor phase Hg
concentration levels in the stack. Record the data on a form similar
to Table 30A-2 in Section 17.0. The system integrity check
specification in Section 13.2 must be met for both the zero gas and
the mid- or high-level gas. If the system integrity specification is
not met for both gases, take corrective action and repeat the test
until an acceptable system integrity check is achieved.
    8.2.6 Measurement System Response Time. The measurement system
response time is used to determine the minimum sampling time for
each sampling point and is equal to the time that is required for
the measured Hg concentration to increase from the stable low-level
calibration gas response to a value within 5 percent of the stable
high-level calibration gas response during the system calibration
error test in Section 8.2.4. Round off the measured system response
time to the nearest minute.
    8.2.7 Dynamic Spiking Test. You must perform dynamic spiking
prior to the first test run to validate your test data. The purpose
of this procedure is to demonstrate that the site-specific flue gas
matrix does not adversely affect the accuracy of the measurement
system. The specifications in Section 13.5 must be met to validate
your data. If these specifications are not met for the pre-test
dynamic spiking, you may not proceed with the test until
satisfactory results are obtained. For the time period between the
effective date of this method and January 1, 2009, the dynamic
spiking requirement is waived.
    <IP_ADDRESS> How do I perform dynamic spiking? Dynamic spiking is a
gas phase application of the method of standard additions, which
involves injecting a known quantity of Hg into the measurement
system upstream of all sample conditioning components, similar to
system calibration mode, except the probe is not flooded and the
resulting sample stream includes both effluent gas and the spike
gas. You must follow a written procedure that details how the spike
is added to the system, how the spike dilution factor (DF) is
measured, and how the Hg concentration data are collected and
processed.
    <IP_ADDRESS> Spiking Procedure Requirements.
    <IP_ADDRESS>.1 Spiking Gas Requirements. The spike gas must also be a
HgCl2 calibration gas certified by an EPA traceability
protocol. You must choose concentrations that can produce the target
levels while being injected at a volumetric flow rate that is < =20
percent of the total volumetric flow rate through the measurement
system (i.e., sample flow rate plus spike gas flow rate).
    <IP_ADDRESS>.2 Target Spiking Level. The target level for spiking
must be 150 to 200 percent of the native Hg concentration; however,
if the native Hg concentration is < 1 [mu]g/m\3\, set the target
level to add between 1 and 4 [mu]g/m\3\ Hg+\2\ to the
native concentration. Use Equation 30A-5 in Section 12.5 to
calculate the acceptable range of spike gas concentrations at the
target level. Then select a spike gas concentration in that range.
    <IP_ADDRESS>.3 Spike Injections. You must inject spikes in such a
manner that the spiking does not alter the total volumetric sample
system flow rate and dilution ratio (if applicable). You must
collect at least 3 data points, and the relative standard deviation
(RSD) specification in Section 13.5 must be met. Each data point
represents a single spike injection, and pre- and post-injection
measurements of the native Hg concentration (or diluted native
concentration, as applicable) are required for each spike injection.
    <IP_ADDRESS>.4 Spike Dilution Factor (DF). For each spike injection,
DF, the dilution factor must be determined. DF is the ratio of the
total volumetric flow rate of gas through the measurement system to
the spike gas flow rate. This factor must be >=5. The spiking mass
balance calculation is directly dependent on the accuracy of the DF
determination. As a result, high accuracy total volumetric flow rate
and spike gas flowrate measurements are required. These flow rates
may be determined by direct or indirect measurement. Calibrated flow
meters, venturies, orifices or tracer gas measurements are examples
of potential flow measurement techniques.
    <IP_ADDRESS>.5 Concentrations. The measurement system must record
total vapor phase Hg concentrations continuously during the dynamic
spiking procedure. It is possible that dynamic spiking at a level
close to 200 percent of the native Hg concentration may cause the
measured Hg concentration to exceed the calibration span value.
Avoid this by choosing a lower spiking level or by recalibration at
a higher span. The measurements shall not exceed 120 percent of the
calibration span. The ``baseline'' measurements made between spikes
may represent the native Hg concentration (if spike gas flow is
stopped between injections) or the native Hg concentration diluted
by blank or carrier gas flowing at the same rate as the spike gas
(if gas flow cannot be stopped between injections). Each baseline
measurement must include at least 4 readings or 1 minute (whichever
is greater) of stable responses. Use Equation 30A-10 or 30A-11 in
Section 12.10 (as applicable) to convert baseline measurements to
native concentration.
    <IP_ADDRESS>.6 Recovery. Calculate spike recoveries using Equation
30A-7 in Section 12.7. Mass recoveries may be calculated from stable
responses based on injected mass flows or from integrated response
peaks based on total mass injected. Calculate the mean and RSD for
the three (or more) spike injections and compare to the
specifications in Section 13.5.
    <IP_ADDRESS>.7 Error Adjustment Option. You may adjust the
measurement data collected during dynamic spiking for the system
calibration error using Equation 30A-3 in Section 12. To do this,
perform the initial system integrity check prior to the dynamic
spiking test, and perform another system integrity check following
the dynamic spiking test and before the first test run. If you
choose this option, you must apply Equation 30A-3 to both the spiked
sample concentration measurement (Css) and the baseline
or native concentration measurement (Cnative), each
substituted in place of Cavg in the equation.
    <IP_ADDRESS> Example Spiking Procedure Using a Hot Vapor Calibration
Source Generator.
    (a) Introduce the spike gas into the probe using a hot vapor
calibration source generator and a solution of HgCl2 in
dilute HC1 and HNO3. The calibrator uses a mass flow
controller (accurate within 2 percent) to measure the gas flow, and
the solution feed is measured using a top-loading balance accurate
to 0.01g. The challenges of injecting oxidized Hg may make it
impractical to stop the flow of gas between spike injections. In
this case, operate the hot vapor calibration source generator
continuously during the spiking procedure, swapping blank solutions
for HgCl2 solutions when switching between spiking and
baseline measurements.
    (b) If applicable, monitor the measurement system to make sure
the total sampling system flow rate and the sample dilution ratio do
not change during this procedure. Record all data on a data sheet
similar to Table 30A-5 in Section 17.0. If the Hg measurement system
design makes it impractical to measure the total volumetric flow
rate through the system, use a spike gas that includes a tracer for
measuring the dilution factor, DF (see Equation 30A-9 in Section
12.9). Allow the measurements to stabilize between each spike
injection, average the pre- and post-injection baseline
measurements, and calculate the native concentration. If this
measurement shifts by more than 5 percent during any injection, it
may be necessary to discard that data point and repeat the injection
to achieve the required RSD among the injections. If the spikes
persistently show poor repeatability, or if the recoveries are not
within the range specified in Section 13.5, take corrective action.
    8.2.8 Run Validation. How do I confirm that each run I conduct
is valid?
    <IP_ADDRESS> System Integrity Checks.
    (a) Before and after each test run, perform a two-point system
integrity check using the same procedure as the initial system
integrity check described in Section 8.2.5. You may use data from
that initial system integrity

check as the pre-run data for the first test run, provided it is the
most recent system integrity check done before the first run. You
may also use the results of a successful post-run system integrity
check as the pre-run data for the next test run. Do not make any
adjustments to the measurement system during these checks, other
than to maintain the target calibration gas flow rate and the proper
dilution ratio.
    (b) As a time-saving alternative, you may, at the risk of
invalidating multiple test runs, skip one or more integrity checks
during a test day. Provided there have been no auto-calibrations or
other instrument alterations, a single integrity check may suffice
as a post-run check to validate (or invalidate) as many consecutive
test runs as can be completed during a single test day. All
subsequent test days must begin with a pre-run system integrity
check subject to the same performance criteria and corrective action
requirements as a post-run system integrity check.
    (c) Each system integrity check must meet the criteria for
system integrity checks in Section 13.2. If a post-run system
integrity check is failed, all test runs since the last passed
system integrity check are invalid. If a post-run or a pre-run
system integrity check is failed, you must take corrective action
and pass another 3-point Hg\0\ system calibration error test
(Section 8.2.4) followed by another system integrity check before
conducting any additional test runs. Record the results of the pre-
and post-run system integrity checks on a form similar to Table 30A-
2 in Section 17.0.
    <IP_ADDRESS> Drift Check. Using the data from the successful pre- and
post-run system integrity checks, calculate the zero and upscale
drift, using Equation 30A-2 in Section 12.3. Exceeding the Section
13.3 specification does not invalidate the run, but corrective
action must be taken and a new 3-point Hg\0\ system calibration
error test and a system integrity check must be passed before any
more runs are made.
    8.3 Dilution-Type Systems--Special Considerations. When a
dilution-type measurement system is used, there are three important
considerations that must be taken into account to ensure the quality
of the emissions data. First, the critical orifice size and dilution
ratio must be selected properly so that the sample dew point will be
below the sample line and analyzer temperatures. Second, a high-
quality, accurate dilution controller must be used to maintain the
correct dilution ratio during sampling. The dilution controller
should be capable of monitoring the dilution air pressure, orifice
upstream pressure, eductor vacuum, and sample flow rates. Third,
differences between the molecular weight of calibration gas
mixtures, dilution air, and the stack gas molecular weight must be
considered because these can affect the dilution ratio and introduce
measurement bias.
    8.4 Sampling.
    (a) Position the probe at the first sampling point. Allow the
system to flush and equilibrate for at least two times the
measurement system response time before recording any data. Then,
traverse and record measurements at all required sampling points.
Sample at each traverse point for an equal length of time,
maintaining the appropriate sample flow rate or dilution ratio (as
applicable). For all Hg instrumental method systems, the minimum
sampling time at each sampling point must be at least two times the
system response time, but not less than 10 minutes. For
concentrating systems, the minimum sampling time must also include
at least 4 concentration measurement cycles.
    (b) After recording data for the appropriate period of time at
the first traverse point, you may move the sample probe to the next
point and continue recording, omitting the requirement to allow the
system to equilibrate for two times the system response time before
recording data at the subsequent traverse points. You must, however,
sample at this and all subsequent traverse points for the required
minimum amount of time specified in this section. If you must remove
the probe from the stack for any reason, you must again allow the
sampling system to equilibrate for at least two times the system
response time prior to resuming data recording.
    (c) If at any point the measured Hg concentration exceeds the
calibration span value, you must at a minimum identify and report
this as a deviation from the method. Depending on the data quality
objectives of the test, this event may require corrective action
before proceeding. If the average Hg concentration for any run
exceeds the calibration span value, the run is invalidated.
    8.5 Moisture Correction. If the moisture basis (wet or dry) of
the measurements made with this method is different from the
moisture basis of either: (1) The applicable emission limit; or (2)
a Hg CEMS or sorbent trap monitoring system being evaluated for
relative accuracy, you must determine the moisture content of the
flue gas and correct the measured gas concentrations to a dry basis
using Method 4 in appendix A-3 of this part or other appropriate
methods, subject to the approval of the Administrator.
    8.6 Optional Interference Test Procedure.
    (a) Select an appropriate calibration span that reflects the
source(s) to be tested and perform the interference check at 40
percent of the lowest calibration span value anticipated, e.g., 10
[mu]g/m\3\. Alternatively, successfully conducting the interference
test at an absolute Hg concentration of 2 [mu]g/m\3\ will
demonstrate performance for an equivalent calibration span of 5
[mu]g/m\3\, the lowest calibration span allowed for Method 30A
testing. Therefore, performing the interference test at the 2 [mu]/
m\3\ level will serve to demonstrate acceptable performance for all
calibration spans greater than or equal to 5 [mu]g/m\3\.
    (b) Introduce the interference test gases listed in Table 30A-3
in Section 17.0 into the measurement system separately or as a
mixture. The interference test gases HCl and NO must be introduced
as a mixture. The interference test gases must be introduced into
the sampling system at the probe such that the interference gas
mixtures pass through all filters, scrubbers, conditioners, and
other components as would be configured for normal sampling.
    (c) The interference test must be performed using
HgCl2, and each interference test gas (or gas mixture)
must be evaluated in triplicate. This is accomplished by measuring
the Hg response first with only the HgCl2 gas present and
then when adding the interference test gas(es) while maintaining the
HgCl2 concentration of the test stream constant. It is
important that the equipment used to conduct the interference test
be of sufficient quality so as to be capable of blending the
HgCl2 and interference gases while maintaining the Hg
concentration constant. Gas blending system or manifolds may be
used.
    (d) The duration of each test should be for a sufficient period
of time to ensure the Hg measurement system surfaces are conditioned
and a stable output is obtained. Measure the Hg response of the
analyzer to these gases in [mu]g/m3. Record the responses and
determine the overall interference response using Table 30A-4 in
Section 17.0 and the equations presented in Section 12.11. The
specification in Section 13.4 must be met.
    (e) A copy of these data, including the date completed and a
signed certification, must be included with each test report. The
intent of this test is that the interference test results are
intended to be valid for the life of the system. As a result, the Hg
measurement system should be operated and tested in a configuration
consistent with the configuration that will be used for field
applications. However, if the system used for field testing is not
consistent with the system that was interference-tested, the
interference test must be repeated before it is used for any field
applications. Examples of such conditions include, but are not
limited to: major changes in dilution ratio (for dilution based
systems), changes in catalyst materials, changes in filtering device
design or materials, changes in probe design or configuration, and
changes in gas conditioning materials or approaches.

9.0 Quality Control

What quality control measures must I take?

    The table which follows is a summary of the mandatory,
suggested, and alternative quality assurance and quality control
measures and the associated frequency and acceptance criteria. All
of the QC data, along with the run data, must be documented and
included in the test report.

                                       Summary Table of QA/QC Requirements
----------------------------------------------------------------------------------------------------------------
     Status \1\       Process or element    QA/QC specification     Acceptance criteria      Checking frequency
----------------------------------------------------------------------------------------------------------------
S..................  Identify Data User..  ....................  Regulatory Agency or       Before designing
                                                                  other primary end user     test.
                                                                  of data.
M..................  Analyzer Design.....  Analyzer range......  Sufficiently > high-level  ....................
                                                                  gas to allow
                                                                  determination of system
                                                                  calibration error.
S..................  ....................  Analyzer resolution   <  2.0 % of full-scale      Manufacturer design.
                                            or sensitivity.       range.
S..................  ....................  Interference          Overall response < = 3% of
                                            response.             calibration span.
                                                                 Alternatively, overall
                                                                  response < = 0.3 [mu]g/
                                                                  m\3\.
M..................  Calibration Gases...  Traceability          Validation of
                                            protocol.             concentration required.
M..................  ....................  High-level Hg\0\ gas  Equal to the calibration   Each calibration
                                                                  span.                      error test.
M..................  ....................  Mid-level Hg\0\ gas.  40 to 60% of calibration   Each calibration
                                                                  span.                      error test.
M..................  ....................  Low-level Hg\0\ gas.  10 to 30% of calibration   Each calibration
                                                                  span.                      error test.
M..................  ....................  High-level HgCl2 gas  Equal to the calibration   Each system
                                                                  span.                      integrity check (if
                                                                                it better
                                                                                represents Cnative
                                                                                than the mid level
                                                                                gas).
M..................  ....................  Mid-level HgCl2.....  40 to 60% of calibration   Each system gas
                                                                  span.                      integrity check (if
                                                                                it better
                                                                                represents Cnative
                                                                                than the high level
                                                                                gas).
M..................  ....................  Zero gas............  .........................  Each system
                                                                                integrity check.
M..................  ....................  Dynamic spike gas     A high-concentration       Pre-test; dynamic
                                            (Cnative >= 1 [mu]g/  HgCl2 gas, used to         spiking not
                                            m\3\).                produce a spiked sample    required until 1/1/
                                                                  concentration that is      09.
                                                                  150 to 200% of the
                                                                  native concentration.
M..................  ....................  Dynamic spike gas     A high-concentration       Pre-test; dynamic
                                            (Cnative <  1 [mu]g/   HgCl2 gas, used to         spiking not
                                            m\3\).                produce a spiked sample    required until 1/1/
                                                                  concentration that is 1    09.
                                                                  to 2 [mu]g/m\3\ above
                                                                  the native concentration.
S..................  Data Recorder Design  Data resolution.....  < = 0.5% of full-scale....  Manufacturer design.
M..................  Sample Extraction...  Probe material......  Inert to sample            Each run.
                                                                  constituents (e.g., PFA
                                                                  Teflon, or quartz if
                                                                  stack > 500 [deg]F).
M..................  Sample Extraction...  Probe, filter and     For dry-basis analyzers,   Each run.
                                            sample line           keep sample above the
                                            temperature.          dew point, by heating
                                                                  prior to moisture
                                                                  removal.
                                                                 For wet-basis analyzers,
                                                                  keep sample above dew
                                                                  point at all times, by
                                                                  heating or dilution.
M..................  Sample Extraction...  Calibration valve     Inert to sample            Each test.
                                            material.             constituents (e.g., PFA
                                                                  Teflon or PFA Teflon
                                                                  coated).
S..................  Sample Extraction...  Sample pump material  Inert to sample            Each test.
                                                                  constituents.
M..................  Sample Extraction...  Manifold material...  Inert to sample            Each test.
                                                                  constituents.
M..................  Particulate Removal.  Filter inertness....  Pass calibration error     Each calibration
                                                                  check.                     error check.
M..................  System Calibration    System calibration    CE < = 5.0 % of the         Before initial run
                      Performance.          error (CE) test.      calibration span for the   and after a failed
                                                                  low-, mid-or high-level    system integrity
                                                                  Hg\0\ calibration gas.     check or drift
                                                                 Alternative                 test.
                                                                  specification: < = 0.5
                                                                  [mu]g/m\3\ absolute
                                                                  difference between
                                                                  system response and
                                                                  reference value.
M..................  System Calibration    System integrity      Error < = 5.0% of the       Before initial run,
                      Performance.          check.                calibration span for the   after each run, at
                                                                  zero and mid- or high-     the beginning of
                                                                  level HgCl2 calibration    subsequent test
                                                                  gas.                       days, and after a
                                                                 Alternative                 failed system
                                                                  specification: < = 0.5      integrity check or
                                                                  [mu]g/m\3\ absolute        drift test.
                                                                  difference between
                                                                  system response and
                                                                  reference value.
M..................  System Performance..  System response time  Used to determine minimum  During initial 3-
                                                                  sampling time per point.   point system
                                                                                calibration error
                                                                                test.
M..................  System Performance..  Drift...............  < = 3.0% of calibration     At least once per
                                                                  span for the zero and      test day.
                                                                  mid- or high-level gas.
                                                                 Alternative
                                                                  specification: < = 0.3
                                                                  [mu]g/m\3\ absolute
                                                                  difference between pre-
                                                                  and post-run system
                                                                  calibration error
                                                                  percentages..
M..................  System Performance..  Minimum sampling      The greater of two times   Each sampling point.
                                            time.                 the system response time
                                                                  or 10 minutes.
                                                                  Concentrating systems
                                                                  must also include at
                                                                  least 4 cycles.
M..................  System Performance..  Percentage spike      Percentage spike           Before initial
                                            recovery and          recovery, at the target    dynamic spiking not
                                            relative standard     level: 100     required until 1/1/
                                            deviation.            10%.                       09.
                                                                 Relative standard
                                                                  deviation: < = 5 percent.
                                                                 Alternative
                                                                  specification: absolute
                                                                  difference between
                                                                  calculated and measured
                                                                  spike values < = 0.5
                                                                  [mu]g/m\3\.

M..................  Sample Point          Number and Location   For emission testing       Prior to first run.
                      Selection.            of Sample Points.     applications, use 12
                                                                  points, located
                                                                  according to Method 1 in
                                                                  appendix A-1 to this
                                                                  part, unless the results
                                                                  of a stratification test
                                                                  allow fewer points to be
                                                                  used.
                     ....................  ....................  For Part 60 RATAs, follow
                                                                  the procedures in
                                                                  Performance
                                                                  Specification 2, section
                                                                  8.1.3, and for Part 75
                                                                  RATAs, follow the
                                                                  procedures in section
                                                                  6.5.6 of appendix A to
                                                                  Part 75. That is:
                     ....................  ....................   At any test
                                                                  location, you may use 3
                                                                  sample points located at
                                                                  16.7, 50.0, and 83.3% of
                                                                  a ``long'' measurement
                                                                  line passing through the
                                                                  centroidal area; or
                     ....................  ....................   At any test
                                                                  location, you may use 6
                                                                  sample points along a
                                                                  diameter, located
                                                                  according to Method 1
                                                                  (Part 75 RATAs, only);
                                                                  or
                     ....................  ....................   At a location
                                                                  where stratification is
                                                                  not expected and the
                                                                  measurement line is >
                                                                  2.4 m (7.8 ft), you may
                                                                  use 3 sample points
                                                                  located along a
                                                                  ``short'' measurement
                                                                  line at 0.4, 1.0, and
                                                                  2.0 m from the stack or
                                                                  duct wall or, for Part
                                                                  75 only, sample points
                                                                  may be located at 4.4,
                                                                  14.6, and 29.6% of the
                                                                  measurement line; or
                     ....................  ....................   After a wet
                                                                  scrubber or at a point
                                                                  where dissimilar gas
                                                                  streams are combined,
                                                                  either locate 3 sample
                                                                  points along the
                                                                  ``long'' measurement
                                                                  line or locate 6 Method
                                                                  1 points along a
                                                                  diameter (Part 75,
                                                                  only), unless the
                                                                  results of a
                                                                  stratification test
                                                                  allow you to use a
                                                                  ``short'' 3-point
                                                                  measurement line or to
                                                                  sample at a single point.
                     ....................  ....................   If it can be
                                                                  demonstrated that stack
                                                                  gas concentration is < =
                                                                  3 [mu]g/m\3\, then the
                                                                  test site is exempted
                                                                  from stratification
                                                                  testing. Use the 3-point
                                                                  ``short'' measurement
                                                                  line if the stack
                                                                  diameter is > 2.4 m (7.8
                                                                  ft) and the 3-point
                                                                  ``long'' line for stack
                                                                  diameters < = 2.4 m (7.8
                                                                  ft).
A..................  Sample Point          Stratification Test   If the Hg concentration    Prior to first run.
                      Selection.            (see Section 8.1.3).  \2\ at each traverse
                                                                  point during the
                                                                  stratification test is:
                                                                  Within  5% of mean, use 1-
                                                                  point sampling (at the
                                                                  point closest to the
                                                                  mean); or.
                                                                  Not within  5% of mean, but
                                                                  is within
                                                                  10% of mean, use 3-point
                                                                  sampling. Locate points
                                                                  according to Section
                                                                  <IP_ADDRESS>.2 of this method.
                     ....................  ....................  Alternatively, if the Hg   Prior to 1/1/09, you
                                                                  concentration at each      may (1) forgo
                                                                  point is:                  stratification
                                                                  Within  0.2 [mu]g/m\3\ of   sampling points (as
                                                                  mean, use 1-point          per Section
                                                                  sampling (at the point     <IP_ADDRESS>.2) or (2)
                                                                  closest to the mean); or.  perform a SO2
                                                                  Not within  0.2 [mu]g/m\3\ of   (see Sections
                                                                  mean, use 3-point          <IP_ADDRESS> and <IP_ADDRESS>
                                                                  sampling. Locate points    of appendix A to
                                                                  according to Section       part 75), in lieu