including sampling, duration and calculations for determining
compliance

in proposed 40 CFR 65.823 through 65.829.
6. What are the additional requirements for batch process operations?
    In proposed 40 CFR 65.835, we have included a method for
demonstrating compliance with an aggregated percent reduction emission
standard. These requirements apply when a referencing subpart allows
the owner or operator to show compliance with a percent reduction by
aggregating emissions over the full batch process. To demonstrate
compliance, the owner or operator would use the proposed engineering
evaluation methodologies to calculate uncontrolled emissions from all
batch process operations for a given process that they do not want to
control. The owner or operator would still determine, through
performance testing, uncontrolled and controlled emissions from batch
process operations that are controlled. All emissions from all batch
process operations (i.e., those emissions determined from the proposed
engineering evaluation methodologies and those emissions determined
from performance testing) would then be considered when determining
compliance with the percent reduction emission limit.
    In addition, we are proposing that you use these engineering
evaluation methodologies if you choose to develop an emissions profile
by process for determining absolute worst-case conditions of your batch
process operations. You would also use these methodologies as part of
your condenser design evaluation (see the specific condenser section of
section V.B.3 of this preamble).
7. How can I demonstrate compliance through design evaluation?
    Except for condensers, under the proposed standards, you may
demonstrate compliance for a non-flare control device by conducting a
design evaluation in lieu of a performance test, if allowed by the
referencing subpart. The design evaluation would require documentation
that the control device being used achieves the emission limit required
by the referencing subpart. For condensers, we are proposing that you
must conduct a design evaluation (see section V.B.3 of this preamble).
The evaluation must also include documentation of the composition of
the vent stream entering each control device, including flow, regulated
material concentration and other site-specific information for each
control device, as provided in proposed 40 CFR 65.850. If you choose to
do a design evaluation, you would also submit a monitoring description
with the Notification of Compliance Status. The monitoring description
would contain a description of the parameters to be monitored and the
associated operating limit(s), an explanation of the criteria used for
selection of that parameter (or parameters) and the operating limit(s),
the frequency with which monitoring will be performed, and the
averaging time for each operating parameter being measured. Once the
design evaluation has been conducted and operating parameters have been
established, the non-flare control device must be operated and
maintained such that the monitored parameters remain within the
established operating limit.
8. What are the recordkeeping, notification and reporting requirements?
    We are proposing that each owner or operator of the affected
control device must keep the records in proposed 40 CFR 65.860. These
include:
     Continuous records of the monitoring equipment operating
parameters or emissions. If certain requirements are met, you have the
option of maintaining a record of each measured value, or block hourly
average data and the most recent three valid hours of continuous
records.
     Records of the daily average value or operating block
average value of each continuously monitored parameter or emissions for
each operating day.
     Non-continuous records as specified in 40 CFR 65.860(b).
     Records of each operating scenario, each emission episode,
and each emission profile you develop as described in proposed 40 CFR
65.860(f) for batch operations.
     Control device monitoring, calibration and maintenance
records.
     Records of periods when the regulated source, control
equipment or CPMS are out of control, inoperative or are not operating
properly.
     For batch process operations, records of whether each
batch operation was considered a standard batch, including estimated
uncontrolled and controlled emissions for each nonstandard batch.
     Performance test records for each performance test
performed, as described in proposed 40 CFR 65.820 through 65.829 (and
discussed further in section V.A.7 of this preamble). For control
devices for which a performance test is required, you would be required
to keep records of the percent reduction of regulated material achieved
by the control device or the concentration of regulated material at the
outlet of the control device, as applicable.
    You would be required to submit the reports in proposed 40 CFR
65.880, 65.882, 65.883 and 65.884; certain reports must be submitted
electronically, as specified in the proposed 40 CFR part 65, subpart H
(see section II.F and VI.B.7 of this preamble). As specified in
proposed 40 CFR 65.880, you would be required to submit the
Notification of Compliance Status by the date provided by the
referencing subpart. The Notification of Compliance Status would
require certifications of compliance with rule requirements, including
batch calculations and design evaluation records. The report would also
include the established operating limit for each monitored parameter.
For halogenated vent streams, you would be required to identify any
halogenated vent streams as part of the Notification of Compliance
Status. The Notification of Compliance Status would also include a
statement about any emissions being routed to a fuel gas system. For
existing control devices that may be redirected to the Uniform
Standards as current regulations are revised, you would also be
required to submit a Notification of Compliance Status. However, in
order to reduce burden for transitioning sources, we are providing that
you would be allowed to rely on previous performance test reports as
part of the submittal, as long as the performance test was conducted
within the past 5 years and conducted as specified under proposed
subpart M. As discussed in section V.A.4 of this preamble, some
transitioning sources may be required to conduct a performance test in
cases where new parameter monitoring is required.
    You would be required to submit semi-annual and annual periodic
reports according to the requirements in proposed 40 CFR 65.882 and
65.883. Generally, semi-annual reporting of deviations is required to
submit electronically, and annual reporting of non-deviation elements
is required to be submitted in hard copy, as discussed under Types of
reports in section VI.B.7 of this preamble. We are proposing, under 40
CFR 65.884, that you submit certain reports at varying times, based on
the activity being reported, including a notification of the
performance test, any application to substitute a prior performance
test for an initial performance test, a CEMS performance evaluation
notification or CPMS monitoring plan submittal, a batch pre-compliance
report and certain information, if you chose to use a control device
other than those listed in this subpart.

9. When must I comply with the proposed standards?
    We are not proposing to specify a compliance timeline in subpart M,
so the compliance timeline specified in the referencing subpart would
apply for that source category.

B. Rationale

    This section provides rationale for the proposed compliance
requirements for vent streams that are routed to fuel gas systems or
through closed vent systems to control devices. Rationale for the
associated monitoring, performance testing, reporting and recordkeeping
requirements is also included.
    In keeping with our intent to provide a smarter, streamlined
process for rulemaking and ensure consistent standards across multiple
source categories, we have structured the National Uniform Emission
Standards for Control Devices to provide a common set of monitoring,
testing, recordkeeping and reporting requirements that may be
referenced from multiple regulations, including NSPS and NESHAP. The
proposed Uniform Standards in 40 CFR part 65, subpart M are generally
based on a review of the Generic MACT standards of 40 CFR part 63,
subpart SS. Additionally, we reviewed other recent rules, the
applicability determination index database, test reports and recent EPA
decisions to identify advances in control technologies, monitoring and
compliance approaches. This is in keeping with our intent that the
proposed National Uniform Emission Standards for Control Devices would
provide a set of supporting requirements that could be considered in
future rulemakings under CAA section 111 and 112 to meet the applicable
statutory requirements.
    The requirements for 40 CFR part 63, subpart SS were chosen as the
best starting point for these proposed standards because they were
previously developed for the purpose of providing consistent control
device requirements that could be referenced by multiple NESHAP
subparts, and they already incorporate some improvements based on the
EPA's experience with implementation of other subparts, such as the MON
(71 FR 40333, issued on July 14, 2006) and the HON (59 FR 19402, issued
on April 22, 1994). We have augmented the subpart SS provisions by
adding requirements from other subparts to provide additional
continuous monitoring options, to better accommodate batch processes
and to provide requirements for additional regulated materials (e.g.,
metals, PM) and types of control devices (e.g., fabric filters, sorbent
injection) not covered by subpart SS.
    We have developed the Uniform Standards for Control Devices to
create a set of requirements that will ensure continuous compliance
with the standards established under a referencing subpart. In
developing the proposed requirements, we had the opportunity to review
typical compliance methods for control devices controlling vent streams
from regulations representing a variety of source categories. From this
review, we considered the variation in requirements between rules and
identified the most effective requirements for each control device. As
such, we are proposing subpart M with more stringent requirements than
may currently apply to some source categories; however, this stringency
can always be overridden by the referencing subpart if deemed
appropriate for the particular source category. These more stringent
requirements reflect our intention to provide a consistent set of
monitoring, recordkeeping and reporting requirements that reflect the
most current control technologies and that are accessible and
applicable for the majority of source categories complying with MACT
and that would potentially reference the Uniform Standards to meet
MACT. These consistent standards, if promulgated, will reduce the
current overlapping and inconsistent provisions from multiple NSPS and
NESHAP that may apply to a single source into a single set of
requirements, thereby reducing the compliance burden for sources and
government alike. Providing this common set of requirements also
circumvents any undue burden on a single source category (for instance,
source categories currently subject to multiple regulations).
Furthermore, this approach would reduce the number of requests for
alternative monitoring requirements, which are frequently made by
sources required to comply with multiple NESHAP and NSPS. The proposed
Uniform Standards for Control Devices also provide some additional
requirements in places that we discovered, through our regulatory
survey, were not adequately addressed by current regulations (e.g., we
have included provisions for regenerative carbon absorbers that specify
how the source should handle desorbed contaminants). We note that the
referencing subpart establishes the applicability of the Uniform
Standards for Control Devices and the specific provisions of subpart M
that may apply; therefore, a referencing subpart may structure more or
less stringent requirements for a given source category as is best
determined to meet MACT, GACT, AMOS or BSER. (See Relationship to
Referencing Subpart below.)
    In keeping with the objectives of Executive Order 13563, Improving
Regulation and Regulatory Review, we have also incorporated changes to
simplify and streamline the language, improve consistency, incorporate
the latest technical requirements and remove unnecessary regulatory
burden to create the National Uniform Emission Standards for Control
Devices. We believe that these improvements will result in a
consistent, yet flexible set of standards that may be easily referenced
by multiple source categories in CAA section 111 and 112 rulemakings,
resulting in a more efficient regulatory process that will benefit both
regulated entities and government agencies. Throughout this section, we
will describe the rationale for each major proposed change from the
previous rules.
    Relationship to Referencing Subpart. In contrast to the Uniform
Standards for Storage Vessels and Transfer Operations and the Uniform
Standards for Equipment Leaks, the proposed subpart M does not
establish applicability thresholds or control levels that may be relied
upon by a referencing subpart. Rather, subpart M requires that the
referencing subpart establish all applicability, including thresholds
or tiers. We have developed subpart M without these types of thresholds
because there is a greater variety of emission streams expected to be
controlled under subpart M. Storage tanks and equipment leaks are
generally controlled on a unit level, with a standard configuration,
and the emissions mechanism by which pollutants are released to the
atmosphere from these emission points is generally limited. In general,
these emissions points are single points that, individually, do not
represent large emission sources, and that all behave similarly.
Therefore, control of emissions from these points has historically been
homogenous with applicability thresholds and control levels that are
easily set; storage tanks, for instance, have historically been
controlled using preventative maintenance practices, while emissions
from equipment leaks have been historically controlled by LDAR
requirements.
    Conversely, subpart M provides requirements for control devices
that may control a variety of emission

streams with various configurations, flow and concentrations. It is
possible for multiple process streams throughout a facility to be
joined with and directed to a single control device in numerous
configurations, combining emissions in one stream for control of a very
large emission source. Furthermore, the number of vents to a control
device may vary greatly across source categories; some source
categories may reflect a standard configuration in which the process
streams require multiple control devices; other source categories may
reflect a standard configuration in which a single process stream
requires control. Because of the many configurations that exist for
individual facilities across multiple source categories, the emissions
mechanism for process streams routed to control devices may vary
greatly. Therefore, we have determined that the referencing subpart is
the best place to determine the applicability threshold or control
level for a specific source category, as the referencing subpart may
consider the unique configurations, flow and concentration of regulated
material within a given process stream or streams.
    The Uniform Standards for Control Devices assume that the
referencing subpart will establish and provide the rationale for the
specific emission limits that best support the source category being
regulated. The referencing subpart would address and assign
applicability thresholds or control levels for any provisions of the
Uniform Standards not cross-referenced by the referencing subpart. The
referencing subpart could cross-reference or make exceptions, as
necessary, to ensure that the proposed requirements of subpart M are
appropriate to the source category. For instance, a referencing subpart
with multiple applicability thresholds may only direct to a portion of
subpart M for sources meeting one of those thresholds. Additionally,
the referencing subpart could determine to not direct to subpart M at
all for certain applicability thresholds. For example, a referencing
subpart may only require CEMS for streams above a defined threshold.
    Organization of Proposed Subpart M. The proposed rule is structured
so that the compliance requirements for each control device are
provided in separate sections. Each control device section includes the
specific requirements for that control device, including monitoring,
performance testing, conducting a design evaluation, and recordkeeping
and reporting. Specific continuous monitoring requirements for control
devices are provided in Tables 1 and 2 of subpart M. We have organized
the standards this way to facilitate ease of reading and understanding,
to congregate requirements for similar control devices in one place and
to remove redundant text. For example, 40 CFR part 63, subpart SS
includes a general section for performance testing procedures
containing a specific requirement regarding the selection of sampling
sites for vent streams introduced with combustion air or as a secondary
fuel into certain types of boilers or process heaters. We have moved
these requirements, specific only to small boilers and process heaters,
to a small boiler and process heater section, which is located in
proposed 40 CFR 65.724. Additionally, although subpart SS includes a
separate section of requirements for halogenated scrubbers, we have
consolidated these provisions with the requirements for absorbers. We
reasoned that a halogenated scrubber is a specific type of absorber,
and the previous requirements overlapped; combining these requirements
reduces redundancy and allows for a streamlined compliance approach.
    Because the proposed standards contain general monitoring and
performance testing requirements that would be applicable to more than
one type of control device, we have included separate sections for
general monitoring requirements and performance testing requirements to
reduce redundancy across rule sections. We additionally congregated the
requirements for the correct operation of CEMS and CPMS, as well as
requirements for establishing the operating parameters for each CPMS,
into individual sections. In addition to the specific control device
section that applies to you, you would comply with these proposed
general monitoring requirements, located in 40 CFR 65.710 through
65.712. Likewise, you would comply with the proposed general
performance testing requirements in 40 CFR 65.820 through 65.829, which
include detailed provisions on the methods required for testing. We
have also designated a section for general requirements for performing
design evaluations. It is our intent that the proposed standards of
subpart M, as organized, will have improved clarity and consistency,
which will facilitate both reading and compliance as the standards are
referenced in future rulemakings.
    General differences between proposed 40 CFR part 65, subpart M and
40 CFR part 63, subpart SS. Although the requirements of subpart M are
primarily based on 40 CFR part 63, subpart SS, we revised some of the
terminology used in subpart SS to provide clarification and accommodate
the broad range of source categories and control devices that could be
covered by the proposed standards in the future. The National Uniform
Emission Standards for Control Devices are intended to provide a common
set of testing, monitoring, recordkeeping and reporting requirements
that may be referenced from multiple regulations, including NSPS and
NESHAP. Therefore, subparts referencing subpart M may define a range of
pollutants and pollutant types (e.g., HAP, criteria pollutants). To
accommodate the variety of pollutants and pollutant types that may be
regulated under future NSPS and NESHAP, we have used the term
``regulated material'' to mean the pollutant regulated by the
referencing subpart. We have also used the term ``oxidizer'' in lieu of
``incinerator'' to refer to control devices such as thermal and
catalytic oxidizers in order to differentiate these devices from other
regulated incineration units.
    We revised some provisions included in 40 CFR part 63, subpart SS
that are redundant or unclear, including the ``route to process''
provisions. Subpart SS includes an option to route regulated material
emissions from non-process operations (i.e., storage tanks, transfer
equipment and equipment leaks) to a process for control. The
monitoring, recordkeeping and reporting language from subpart SS for
this option is not included in proposed subpart M, as these
requirements add unnecessary regulatory burden. The proposed Uniform
Standards are consistent with the intent of subpart SS, in that owners
and operators will continue to have the flexibility to route vent
streams, as necessary, to control releases. However, these emission
streams will not be subject to additional monitoring, recordkeeping and
reporting if they are simply integrated into the process. We have
assumed that vent streams that are routed to a process would be
eventually released to the atmosphere through a regulated emissions
point (e.g., process operation, wastewater stream, equipment leak,
etc.) or incorporated into a product or byproduct. Therefore, these
requirements were unclear and unnecessary for the purposes of subpart
M. We are soliciting comments on this change, including comment on the
assumptions presented in this section. We are also requesting comments
on whether some vent streams routed to the process are not released to
the atmosphere through a regulated emissions point.
    The proposed subpart M does not contain requirements for flares.

Proposed subparts I and J refer to 40 CFR 63.11(b) of subpart A for
emissions routed to flares from storage tanks, transfer operations, and
leaking equipment. It is anticipated that for process vents controlled
by flares, a referencing subpart will reference either 40 CFR 63.11(b)
of subpart A or include other provisions that are determined to be
applicable for flares used at the source category regulated by the
referencing subpart. However, we are in the process of gathering data,
reviewing flare research papers and test reports, and investigating
operating conditions that may impact the performance of a flare,
including situations of over steaming, excess aeration, flame lift off,
and high winds. Based on this information, we may in the future propose
to add new flare requirements to the Uniform Standards in subpart M,
which can be referenced by subparts I and J and referencing subparts.
1. How did the EPA determine the general monitoring requirements and
the requirements for CEMS and CPMS?
    The general monitoring requirements that we are proposing are
modeled after specific requirements from 40 CFR part 63, subpart SS,
which were based on monitoring and inspection requirements previously
developed by the EPA for use in implementing standards for various
chemical industry sources. We are supplementing these requirements by
proposing continuous monitoring through the installation and operation
of either a CEMS or a CPMS. CEMS have been widely used to demonstrate
that air pollution control devices are being operated in a manner that
ensures that emission limitations are being met, and recent regulations
reflect the increasing use of CEMS as a monitoring device across
multiple source categories. However, in evaluating the use of CEMS in
multiple NESHAP, we determined that monitoring of individual regulated
materials may not be reasonable or technically feasible for certain
streams. For instance, CEMS may not be available for certain individual
HAP species, or may not be economically feasible for smaller sources.
In such cases, parameter monitoring provides an alternative option that
ensures the control device is operating consistently and continues to
achieve the required emission limits. This also provides a more cost-
efficient option for some sources, without reducing compliance.
Therefore, in order to create a set of standards that could be applied
to a broader range of source categories, we have included requirements
for both CEMS and CPMS. During the development of referencing subparts
that will direct to the Uniform Standards, we will continue to assess
the best monitoring option for a given source category from a technical
and economic standpoint. We will provide rationale upon proposal or
promulgation as to why CEMS or CPMS would be more appropriate for an
individual source category, or whether additional flexibility for
industry and reduced burden on smaller sources within an individual
source category could be granted by allowing either a CEMS or CPMS to
be used. We anticipate that in future regulations, the referencing
subpart may even override the monitoring options of the proposed
subpart M and require a specific monitoring technique.
    We have incorporated and updated the CEMS requirements established
in the MON, which were developed in consideration of a combination of
monitoring requirements from the HON and Pharmaceuticals Production
source categories. We have supplemented these requirements with
provisions based on the CEMS-specific requirements of 40 CFR part 63,
subpart A. These provisions are consolidated under proposed 40 CFR
65.711 in order to establish a set of similar requirements for CEMS in
one place that may more generally apply to sources regulated under 40
CFR part 60, 61 or 63 in future rulemakings.
    For CPMS, we selected monitoring equipment criteria for overall
system accuracy and compatibility. These requirements, which ensure
accuracy in measurements and provide confidence for testing results,
were inconsistently provided in previous regulations. When these
criteria are not established, there is potential that sources could
elect to use very costly CPMS equipment, which is inappropriate or
ineffective for measuring certain parameters and, therefore, provides
inadequate data for the source category. By applying a consistent set
of criteria that applies to multiple source categories, we are
improving data accuracy, reducing potential costs and removing undue
burden for specific source categories. We are requesting comment on
whether the proposed approach for establishing CEMS calibration ranges
and assessing performance will adequately ensure the accuracy of the
reported average emissions that might include measurements at
concentrations above the span value. We are also seeking comments on
how owners and operators of CPMS are currently employing quality
control and calibration methods. Additionally, we welcome information
on the lifetime and degradation of CPMS equipment used to measure
temperature, liquid or gas volumetric flow, pH, mass flow, pressure and
sorbent injection; and whether a ``sunset period'' for existing CPMS
equipment is necessary in cases where the lifetime of the monitoring
components is limited.
    The requirements for measurement range were selected to ensure that
the CPMS could detect and record measurements beyond the normal
operating range. We believe that requiring a range of at least 20
percent beyond the normal operating range is reasonable and the minimum
measurement range needed to encompass most deviations. Owners and
operators may desire to select equipment with even wider ranges if it
is likely that measurements beyond 20 percent of the normal operating
range will occur. Additionally, we are requiring a resolution of one-
half the accuracy requirement or better to ensure that the accuracy of
the CPMS can be calculated to at least the minimum number of
significant figures for the data accuracy assessment to be meaningful.
Selecting a resolution of one-half the required accuracy ensures that
measurements made during validation checks can be readily compared to
the accuracy requirement. We are soliciting comments on whether the
proposed measurement range and accuracy requirements are reasonable and
consistent with what is currently being used.
    We are proposing calibration and quality control requirements for
CPMS to ensure that measured parameter data is accurate to demonstrate
compliance with the referencing subpart. These measures, which
establish requirements for the design, operation and evaluation of
CPMS, are intended to ensure the generation of good quality data both
initially and on an ongoing basis and determine that the control device
is meeting the required emission limit, as specified in the referencing
subpart. The specifications are located in Table 4 to proposed subpart
M and would apply if you were to use a temperature, liquid or gas
volumetric flow, pH, mass flow, pressure or sorbent injection
measurement device to determine compliance with an operating limit.
These requirements also reflect the EPA's intention to improve the
quality of data collected and disseminated by the agency, which will
improve the quality of emission inventories and, as a result, future
air quality regulations.
    For temperature CPMS, we reviewed rules promulgated under parts 60,
61 and 63 that specify accuracy requirements for temperature. Although
there is a wide range of accuracies specified in these rules, the
accuracy

required for temperature CPMS associated with high temperature (non-
cryogenic) applications, such as thermal oxidizers or boilers,
generally ranges from 0.75 to 1.0 percent or from 0.5 degrees Celsius
to 2.5 degrees Celsius (0.9 degrees Fahrenheit to 4.5 degrees
Fahrenheit). For lower temperature (cryogenic) applications, such as
wet scrubbers, the specified percent accuracies often are not as
stringent; that is, accuracies are specified as a higher percentage of
the measured temperature. The reason for specifying higher-percentage
accuracy for lower temperature ranges is to offset the fact that the
accuracy percentage applies to a lower value. Our selection of
temperature accuracies of 2.8 degrees Celsius (5 degrees Fahrenheit) or
1 percent for non-cryogenic applications, and 2.8 degrees Celsius (5
degrees Fahrenheit) or 2.5 percent for cryogenic applications is
consistent with the required accuracies for most standards, and we
believe that the accuracies specified in the proposed performance
specifications are adequate for ensuring good quality data. In
addition, a review of vendor literature indicates that temperature CPMS
that satisfy these accuracy requirements are readily available at
reasonable costs.
    Rules promulgated under parts 60, 61 and 63 that require flow rate
monitoring specify flow rate accuracy in terms of percent. For liquid
flow rate measurement, these rules generally require accuracies of 5
percent, and rules that require steam flow rate monitoring generally
require an accuracy of 10 percent or better. We have revised these
performance specifications in the proposed subpart M to require
accuracies of 2 percent over the normal range of flow measured. Based
on our review of vendor literature, we determined a 2-percent accuracy
criterion is appropriate and available. Recognizing the differences in
the relative magnitudes and the commonly used units of flow rate
measurement for liquids and gases, we have specified in the proposed
performance standards separate accuracy criteria for liquid and gas
flow rates. For liquid flow rate CPMS, which typically are associated
with wet scrubber operation, the minimum accuracy would be 1.9 liters
per minute (0.5 gallons per minute) or 2 percent, whichever is greater.
For gas flow rate CPMS, which often are used to monitor stack gas flow
rate, the proposed performance specifications would require a minimum
accuracy of 28 liters per minute (10 cubic feet/minute) or 2 percent,
whichever is greater. The relative accuracy criterion of 2 percent was
selected because the proposed Uniform Standards have been developed to
provide the greatest level of air emissions control that may be
required by a referencing subpart. As advancements in technology have
improved (and are estimated to continue to improve), we have determined
that future rulemakings would require more stringent accuracy
requirements, and a 2-percent accuracy criterion is reasonable and
achievable for the currently available flow CPMS. We note that these
requirements could be revised by the referencing subpart, if a higher
or lower accuracy is deemed more appropriate for a specific source
category.
    Although we have incorporated an accuracy criteria for liquid flow
rate and gas flow rate as a percent of flow rate and in units of
volumetric flow in proposed subpart M, we have concluded that it would
not be reasonable to specify accuracy criteria for mass flow in units
of mass flow because of the wide range of flow rates that could be
monitored (e.g., carbon injection rate v. rotary kiln raw material feed
rate). As discussed above for liquid flow rate and gas flow rate, the
2-percent accuracy criterion is based on our review of vendor
literature and is a reasonable and achievable requirement for the
currently available mass flow CPMS.
    Manufacturer and vendor literature indicates that pH CPMS generally
have accuracies of 0.01 to 0.15 pH units. Based largely on the vendor
literature, we have decided to require pH CPMS to have accuracies of
0.2 pH units or better. An accuracy of 0.2 pH units should allow most
facilities that currently monitor pH to continue using their pH CPMS,
provided the CPMS satisfies the other criteria specified in the
proposed Uniform Standards for Control Devices.
    For pressure monitoring, we reviewed the existing part 60, 61 and
63 rules that require pressure monitoring. These rules also specify a
minimum accuracy. The accuracy specified generally is either 0.25 to
0.5 kilopascals (kPa) (1 to 2 inch water column (in. wc)) or 5 percent
for pressure drop, and 5 to 15 percent for liquid supply pressure. A
review of vendor literature indicates that most pressure transducers
are accurate from 0.25 to 1.0 percent, and all but the lowest grade
(Grade D) of American National Standards Institute (ANSI)-rated
pressure gauges have accuracies better than 5 percent. For the proposed
performance specifications for CPMS, we selected an accuracy
requirement of 0.12 kPa (0.5 in. wc) or 1.0 percent, whichever is
greater. We believe this level of accuracy is appropriate, considering
that some control devices operate with pressure drops of less than 1.2
kPa (5 in. wc). This criterion was selected because the proposed
Uniform Standards have been developed to provide the greatest level of
air emissions control that may be required by a referencing subpart.
The one percent criterion is consistent with vendor literature, which
indicates that CPMS that are capable of achieving this accuracy are
readily available.
    For sorbent injection, we are specifying accuracy requirements of
within 5 percent of the normal range for the sorbent injection rate,
with annual performance evaluations and 3-month visual checks. These
requirements are consistent with the accuracy requirements for other
CPMS, including the requirements for carrier gas flow rate monitors (a
similar type of monitor) in the Standards of Performance for New Sewage
Sludge Incineration Units (76 FR 15404, March 21, 2011).
    If your operation could be intermittent, we are requiring that you
install and operate a flow indicator to identify periods of flow and no
flow at the inlet or outlet of the control device. The proposed
requirements are necessary to identify periods when monitored parameter
or emission readings are not required or erroneous and should not be
included in the daily or operating block average values. It is not
necessary to monitor a control device during periods when regulated
material is not routed to the control, and monitoring data during these
times should not be averaged in calculating the daily or operating
block average. We are proposing an annual verification check of the
flow indicator to ensure that it is correctly identifying periods of no
flow. We are not considering the flow indicator to be a CPMS that must
meet all the provisions of proposed 40 CFR 65.712.
    We are proposing to include monitoring requirements from the
General Provisions of parts 60, 61 and 63 in the monitoring sections of
subpart M. This places all the applicable requirements associated with
monitoring (including quality checks, monitoring plan requirements,
calibration, monitoring data reduction, recordkeeping and reporting) in
one place and consolidated using consistent terminology. For instance,
we are including provisions for a CEMS performance evaluation and
monitoring plan and a CPMS monitoring plan (formerly the ``site-
specific performance evaluation plan'') from the part 63 General
Provisions (40 CFR 63.8) in proposed 40 CFR 65.711 and 65.712,

respectively. Subpart A of 40 CFR part 63 states that a specific
subpart will indicate whether the plan must be submitted to the
Administrator for approval. In the proposed rule, we are requiring that
the plan be sent to the Administrator for approval for sources
regulated under parts 60 and 61, as well as 40 CFR part 63. We have
determined that a CEMS performance evaluation and monitoring plan or a
CPMS monitoring plan, as appropriate, is necessary under subpart M to
demonstrate compliance with the emission limits of a referencing
subpart. However, the source must comply with the CEMS performance
evaluation and monitoring plan or the CPMS monitoring plan upon
submitting it to the Administrator. Changes may be necessary when the
Administrator completes the review.
2. How did the EPA determine the requirements for closed vent systems?
    Under the proposed standards, all closed vent systems would be
required to meet the applicable provisions of proposed 40 CFR part 65,
subpart J (see section IV.A of this preamble) as they apply to the
individual equipment components that comprise the closed vent system.
In previous rules, equipment that are in closed vent systems have been
subject to annual monitoring and have not been subject to more frequent
monitoring. We are proposing these requirements to ensure that a vent
stream in regulated material service is properly routed to the closed
vent system and delivered to the control device for reduction. The
proposed rule also requires you to install and maintain a CPMS for flow
through a bypass for each closed vent system bypass line that could
divert a vent stream to the atmosphere. The CPMS for flow must be
capable of recording the volume of the gas that bypasses the control
device and be equipped with an alarm system that will alert an operator
immediately and automatically when flow is detected in the bypass.
These provisions are to ensure that any flow directed through a bypass
is detected and identified by the operator. Alternatively, you may
secure the bypass line valve in the non-diverting position with a seal
mechanism. For this option, you would be required to inspect the seal
or closure mechanism at least once per month to confirm that the valve
is in the non-diverting position, or, for a lock-and-key type lock,
maintain records that the key has been checked out. If the alarm sounds
or if it is determined during the monthly inspection that a bypass has
occurred, you would be required to report a deviation and to include an
estimate of the resulting emissions of regulated material that bypassed
the control device. The EPA's intent is that control devices are not to
be bypassed; therefore, use of the bypass at any time to divert a
regulated vent stream to the atmosphere would be a deviation from the
emissions standards set forth by the referencing subpart.
    We have not included requirements from 40 CFR part 63, subpart SS
that provided monitoring exclusions for equipment such as PRD, low leg
drains, high point bleeds, analyzer vents and open-ended valves or
lines needed for safety purposes. This equipment could provide a means
of bypassing the control device; therefore, we are proposing bypass
monitoring for these devices under subpart M of the proposed standards.
It is our intent that analyzer vents should be subject to the control
requirements for sampling connection systems in 40 CFR part 63, subpart
UU. Additionally, applying the bypass monitoring requirements to PRD,
low leg drains, high point bleeds, analyzer vents and open-ended valves
or lines are consistent with the District of Columbia Circuit Court's
2008 ruling in Sierra Club v. EPA, which states that emission standards
must apply at all times (see section VI.B.5 of this preamble). For a
discussion of the economic and cost impacts of these monitoring
requirements, see section VII of this preamble.
    Following the guidance of Executive Order 13563, Improving
Regulation and Regulatory Review, we have not included requirements
from 40 CFR part 63, subpart SS that we determined were redundant or an
unnecessary burden on sources. For instance, although we are not
changing the intent of the requirements from subpart SS, we have not
included language providing specific instructions for bypass monitoring
for loading arms and PRD at transfer racks; specifically, these
provisions required that closed vent systems collecting regulated
material from a transfer rack be operated such that regulated material
vapors collected at one loading arm would not pass through another
loading arm to the atmosphere. For PRD, the requirements prevented the
PRD in the transfer rack's closed vent system from opening to the
atmosphere during loading. These provisions are equivalently handled
under the general bypass monitoring requirements of proposed 40 CFR
65.720(c) for closed vent systems, in which you would be required to
prevent diversion of the stream to the atmosphere. Therefore, we are
not including specific language associated with bypasses from transfer
rack closed vent systems, as this additional language is redundant to
the general bypass requirement. The requirement not to bypass remains.
3. How did the EPA determine the proposed compliance requirements for
each control device?
    For each control device, we are proposing that you meet the
continuous monitoring requirements of Table 1 or Table 2 to subpart M.
Table 1 to subpart M provides the requirements for facilities who
comply with the referencing subpart using CEMS. We have consolidated
the specific parametric monitoring requirements for each control device
in Table 2 to subpart M to provide the requirements in a simplified,
easily referenced format to facilitate compliance.
    You must conduct a performance test for each control device
according to the requirements of proposed 40 CFR 65.820 through 65.829,
unless you meet the general control measures of proposed 40 CFR
65.702(e). A performance test is required because emissions measurement
remains the best method to demonstrate initial compliance with
regulations and determine control device performance. However, we have
made exceptions for: (1) Control devices for which a CEMS is used to
monitor the performance, (2) when the referencing subpart allows a
design evaluation in lieu of a performance test or (3) if certain
provisions have been made for a performance test extension, exemption
or waiver. These exemptions allow greater flexibility for referencing
subparts and are consistent with our desire to provide workable,
consolidated requirements that could apply across multiple source
categories.
    Small boilers and process heaters. The proposed standards under
subpart M include requirements that apply to small boilers and process
heaters used to control emissions of regulated materials. Small boilers
and process heaters are defined in the proposed rule as having a
capacity less than 44 megawatts (MW) and a design such that the vent
stream is introduced with the combustion air or as a secondary fuel.
The capacity threshold and the monitoring, performance testing and
recordkeeping and reporting requirements for these units were modeled
after 40 CFR 63, subpart SS. We have modified these provisions for the
proposed Uniform Standards to provide clarification for requirements
that were found to be confusing during the implementation of subpart
SS. Under subpart SS, the requirements for boilers and process heaters
overlapped

with the requirements for fuel gas systems.
    Fuel gas system is defined in 40 CFR part 63, subpart SS broadly as
the ``* * * piping * * * that gathers gaseous streams for use as fuel
gas in combustion devices. * * *'' Therefore, owners or operators that
use a boiler or process heater to combust vent gas could be subject to
either the boiler and process heater or the fuel gas system
requirements. The testing and monitoring requirements under the control
device and fuel gas system provisions of subpart SS are the same for
boilers or process heaters larger than 44 MW or which have the vent gas
introduced with or as the primary fuel; performance testing and
monitoring are not required for vent gas routed to a fuel gas system, a
boiler or process heater larger than 44 MW or a boiler or process
heater in which the vent gas is introduced as or with the primary fuel.
However, under the control device provisions of subpart SS, performance
testing and monitoring is required in those situations in which the
vent gas is introduced with combustion air or as a secondary fuel into
a boiler or process heater smaller than 44 MW. Conversely, if these
units (smaller than 44 MW) are part of a fuel gas system, monitoring
and testing is not required under subpart SS. We propose to clarify the
requirements by differentiating small boilers (less than 44 MW) with
vent gas introduced to the boiler with combustion air or as a secondary
fuel from larger units and those units with vent gas introduced as or
with the primary fuel. Therefore, we have distinguished separate
requirements for performance testing and monitoring for small boilers
and process heaters under proposed 40 CFR 65.820 through 65.829, with
specific parametric monitoring requirements specified in Table 2 of
subpart M. Units not considered small boilers or process heaters would
be required to meet the requirements of proposed 40 CFR 65.732 for fuel
gas systems. The proposed fuel gas system provisions also specify that
any small boilers or process heaters that are part of a fuel gas system
must meet the requirements of the small boiler and process heater
provisions. These changes clarify whether each unit would be subject to
the requirements for boilers and process heaters or the requirements
for fuel gas systems.
    Additionally, we are not incorporating the requirements of 40 CFR
63.988(a)(3), which stipulate that the vent stream from the boiler or
oxidizer must be introduced into the flame zone. Although we are
preserving the intent of 40 CFR part 63, subpart SS, we have reasoned
that this language is superfluous. We are proposing to clarify the
definition of small boilers in this category as having a design such
that the vent stream is introduced with the combustion air or as a
secondary fuel. It is assumed that secondary fuel and combustion air
are introduced into the flame zone and, therefore, the vent gas would
be introduced into the flame zone.
    In the proposed rule, we have not included the exemptions from
conducting a performance test or design evaluation included in 40 CFR
part 63, subpart SS for small boilers and process heaters which have
been issued a final permit under 40 CFR part 270 and comply with the
requirements of 40 CFR part 266, subpart H or which have certified
compliance with the interim status requirements of 40 CFR part 266,
subpart H. It is our expectation that these facilities are no longer
subject to the air emissions requirements under the Resource
Conservation and Recovery Act permitting rules (other than requirements
that pertain during startup, shutdown and malfunction (SSM)); rather,
all boilers and oxidizers previously subject to these requirements are
now subject to 40 CFR part 63, subpart EEE. We have included a
performance test exemption for small boilers or process heaters burning
hazardous waste who have certified compliance with the requirements of
40 CFR part 63, subpart EEE by conducting comprehensive performance
tests and submitting a Notification of Compliance Status per 40 CFR
63.1207(j) and 63.1210(d), and who comply with these requirements at
all times, even when burning non-hazardous waste. Additionally, we have
not included the subpart SS provision allowing owners or operators of
small boilers and process heaters with a minimum temperature of 760
degrees Celsius and a minimum residence time of 0.5 seconds to omit the
rationale for these design parameters in the design evaluation (40 CFR
63.985(b)(1)(i)(B)) documentation. This minimum temperature and
residence time does not necessarily ensure a 95- or 98-percent
reduction efficiency for all possible emission stream chemical
compositions (see technical memorandum, Design Criteria for Combustion,
in Docket ID No. EPA-HQ-OAR-2010-0868). Because the Uniform Standards
are designed to provide requirements for a variety of source categories
and emission streams, we are not proposing this exception to design
evaluation rationale. Instead, we are proposing that the owner or
operator of the small boiler or process heater be required to consider
the auto-ignition temperature and the residence time when developing
the rationale showing that their small boiler or process heater meets
the applicable control efficiency and that their chosen operating
parameters and ranges are appropriate. The owner or operator may
determine that the appropriate temperature and residence time are 760
degrees Celsius and 0.5 seconds for their process; however, under the
proposed rule, they would have to provide the rationale in their design
evaluation documentation (see technical memorandum, Design Criteria for
Combustion, in Docket ID No. EPA-HQ-OAR-2010-0868).
    Oxidizers. We are proposing monitoring, recordkeeping and reporting
requirements for oxidizers, based on 40 CFR part 63, subpart SS. We are
proposing the requirements for thermal oxidizers and catalytic
oxidizers in 40 CFR 65.726 and 65.728, respectively; these provisions
are included in separate sections for ease of reading and to
accommodate the additional monitoring requirements that are necessary
to ensure compliance for catalytic oxidizers.
    For catalytic oxidizers, we are including sampling, analysis and
inspection requirements to ensure that the oxidizer is capable of
meeting the required emission limits specified in the referencing
subpart. We are including a monitoring method for inlet temperature
monitoring, provided the difference between the inlet and outlet
temperature of the catalytic bed is less than 10 degrees Celsius. A
differential of 10 degrees Celsius was chosen based upon the accuracy
requirements of temperature monitoring systems specified in this
standard, and the typical operating temperature of a catalytic
oxidizer. Allowing for measurement error on both sides of the oxidizer
(inlet and outlet), 10 degrees Celsius was determined to be a range
within measurement capability. The proposed method would allow you to
determine a schedule for sampling and analysis of the catalyst
activity, based on the degradation rate of the catalyst. If results
from the catalyst sampling and analysis indicate that your catalyst
will become inactive within the next 18 months, you would be required
to replace the catalyst bed or take other corrective action consistent
with the manufacturer's recommendations by 3 months before the catalyst
is anticipated to become inactive or within half the time available
between receiving the catalyst activity report and when the catalyst is
expected to become inactive, whichever is less.

    Additionally, you would be required to conduct an annual internal
inspection of the catalyst bed. The inspection frequency would increase
to semiannual or a more stringent frequency, as specified in proposed
40 CFR 65.728(a)(2)(ii), if any issues are found during the annual
inspection that require corrective action. These requirements are based
on our survey of the MON and the Miscellaneous Metal Parts and Products
Surface Coating NESHAP, which included similar alternatives for
monitoring the inlet stream temperature. The MON provided an option for
monitoring the inlet stream temperature with the requirement of a 12-
month check of the catalyst bed; this option was provided to
accommodate emissions streams with low flow or diluted concentrations
in which it would not always be possible to achieve a measurable
temperature differential.
    As determined under the MON, when monitoring only the inlet
temperature, a catalyst-activity-level check also is needed. This is
because catalyst beds can become poisoned and rendered ineffective
without any apparent change in operation. The proposed sampling,
analysis and inspection requirements discussed above are modeled after
the Miscellaneous Metal Parts and Products Surface Coating NESHAP,
which expand on the MON's requirement to conduct a 12-month check of
the catalyst bed. We are providing the option to determine the schedule
for sampling and analysis based on the degradation of the catalyst to
provide flexibility for multiple source categories that may reference
the Uniform Standards, while ensuring that catalyst beds are replaced
or that other corrective actions are taken in a timely manner. A
referencing subpart may determine the specific sampling and analysis
schedule, in order to ensure compliance, prevent excessive downtime or
avoid unreasonable costs to an individual source category.
    We have included this option in subpart M only for sources in which
the temperature differential between the inlet and outlet of the
catalytic oxidizer during normal operating conditions is less than 10
degrees Celsius. We are not proposing this option for sources with a
temperature differential of greater than 10 degrees Celsius because
inlet and outlet temperature monitoring is a more accurate method of
parameter monitoring and should be used, if possible, to measure the
temperature differential.
    As discussed for small boilers and process heaters in this section,
we have not included the design evaluation or performance test
exemptions included in 40 CFR part 63, subpart SS for oxidizers that
comply with the requirements of 40 CFR part 266, subpart H, but only
those oxidizers burning hazardous waste who have certified compliance
with the requirements of 40 CFR part 63, subpart EEE. Additionally, as
discussed for small boilers and process heaters, we have not included
the subpart SS provision allowing oxidizers with a minimum temperature
and residence time to omit the rationale documentation for the design
evaluation.
    Absorbers. In developing the proposed standards for absorbers, we
have incorporated the monitoring requirements of 40 CFR part 63,
subpart SS and added several monitoring options to accommodate the many
absorber designs that may be used. Alternative monitoring approaches
for absorbers have been the most commonly requested alternative by
industry under current rules. Because of this, we have incorporated
multiple monitoring schemes based upon the alternatives approved by the
EPA, the different monitoring schemes in various chemical sector rules
and support documents prepared by the EPA for the compliance assurance
monitoring (CAM) regulation. (See Technical Guidance Document:
Compliance Assurance Monitoring, August 1998, available at http://www.epa.gov/ttn/emc/cam.html.) Furthermore, because halogenated
scrubbers are a type of absorber and the monitoring requirements are
the same, we have merged the requirements for halogen scrubbers into
the proposed standards for absorbers to reduce redundant text. We
believe that integrating these additional monitoring options into the
proposed standards will reduce the need for owners and operators to
request the use of alternative monitoring requirements and for the EPA
to review these requests, thereby improving the efficiency of the
regulatory process. This is consistent with the objectives of Executive
Order 13563, Improving Regulation and Regulatory Review, which requires
that we periodically review existing regulations to examine ways to
improve regulatory efficacy or reduce burden.
    We are proposing the installation and operation of either a CEMS or
a CPMS, following the requirements in Tables 1 or 2 of proposed subpart
M. As discussed in the general monitoring requirements in section V.B.1
of this preamble, we have included provisions for both CPMS and CEMS to
accommodate the variety of sources that may be controlled by a
referencing subpart.
    The most critical parameter for monitoring absorption systems is
liquid flow to the absorber, therefore we are requiring liquid flow be
monitored for all absorption systems, but have provided an option for
monitoring of the liquid-to-gas ratio. Rather than calculating one
minimum flow rate at maximum operating conditions that must be
continuously adhered to, this alternative provision allows a facility
to optimize the liquid flow for varying gas flow rates. By using a
liquid-to-gas ratio, sources may save resources by reducing the liquid
rate with reductions in gas flow due to periods of lower production
rates.
    Pressure drop is also a valuable operating parameter to monitor for
absorbers. It can signal abnormal column conditions such as plugging,
channeling or mal-distribution of the packing. We are proposing that
you monitor the pressure drop for all absorbers as long as the normal
pressure drop across the absorber is greater than 5 inches of water. If
the pressure drop is typically less than 5 inches of water, it is not a
sensitive monitor for absorber performance. We have also included a
requirement to monitor pH for acid gas absorbers. For non-water
absorbers used for VOC control, we are proposing that the chemical
strength and flow rate of the chemical must be monitored. Monitoring
the oxidation strength and flow rate of the chemical will ensure that
enough chemical is being added to the absorber to attain at least the
required amount of absorption. For particulate and metal absorbers, if
the pressure drop is normally less than 5 inches of water, the owner or
operator will have the choice of monitoring the inlet and outlet gas
temperature; the specific gravity and outlet gas temperature; or the
liquid feed pressure and outlet gas temperature. These monitoring
parameters provide information on whether there has been sufficient
contact between the liquid and gas.
    Similar choices were provided for VOC absorbers if the normal
pressure drop across the absorbers is less than 5 inches of water and
the scrubbing liquid is water. The source would monitor the inlet and
outlet gas temperatures, or the liquid feed pressure and outlet gas
temperature.
    Adsorbers. We are proposing standards for adsorbers used as control
devices, based on the provisions of 40 CFR part 63, subpart SS. We have
clarified language in the proposed adsorber requirements in order to
develop a more inclusive set of

standards. Specifically, we have revised the former subpart SS
requirements for ``carbon adsorbers'' to apply to ``adsorbers,'' and
modified the applicability to pertain to adsorbers containing any type
of adsorbent such as carbon, zeolite or adsorbing polymers. These
proposed standards address many different adsorber configurations
existing in service today, including carbon adsorbers; adsorbers that
use adsorbing media other than carbon; adsorbers that use vacuum as a
regeneration technique; adsorber systems that use steam or other media
for regeneration; and adsorbers that are not regenerated on site. These
changes allow the proposed requirements to be more broadly referenced
in future CAA section 111 and 112 rulemakings and provides additional
options for control for multiple source categories. Additionally, this
change reduces the need for owners and operators to request the use of
alternative adsorbents or monitoring methods and for the EPA to review
these requests, thereby eliminating unnecessary regulatory burden to
industry and improving the efficiency of the regulatory process.
    Many current regulations address carbon adsorber operation, and the
proposed rule has been written to address performance issues that have
been identified by the EPA in implementing and enforcing these rules.
Known performance issues include: The regeneration frequency of the
adsorbent; the effectiveness of regeneration; the life of the adsorbent
material before replacement is required; mechanical issues with the
system operation including valve sequencing; and for non-regenerative
systems, the expected life of the bed before replacement. The proposed
rule incorporates different monitoring requirements for adsorption
systems based on our review of 40 CFR part 63, subparts G, SS, GGG,
MMM, FFFF, GGGGG and BBBBBB, as well as monitoring approaches that have
been outlined and approved by the EPA in monitoring alternative
requests.
    We are proposing the use of CEMS or CPMS to ensure the adsorption
system operates consistently; we have included parametric monitoring
provisions in Table 2 of subpart M in order to accommodate systems
where a CEMS is not used. Because there is no single parameter you can
monitor to ensure that all operating aspects are functioning properly,
the proposal combines several monitoring approaches, each of which
addresses common adsorber system performance issues. These include: (1)
Monitoring of the regeneration process, (2) establishing and adhering
to a regeneration frequency, (3) daily verification of system operating
parameters and (4) routine sampling of the vent stream.
    The regeneration process monitoring provisions for non-vacuum
systems include regeneration stream flow and adsorber temperature.
These are key parameters to ensure the adsorption bed is sufficiently
desorbed at the start of an adsorption cycle, and have long been known
to influence adsorption performance. We have added the requirement to
establish and adhere to a pre-defined interval for regeneration
frequency in order to prevent overloading the bed and possibly
incurring breakthrough during the adsorption cycle before regeneration
is initiated. We considered alternatives to a pre-defined interval that
would take into account the organic loading on the bed, but determined
that regeneration on a prescribed schedule provides greater assurance
that there would be sufficient adsorptive capacity at all times.
    Regenerative adsorption processes are typically multiple bed
systems with complicated valve and piping arrangements designed to
handle the vent streams and desorption streams on a batch basis.
Because the consistent operation of the valves in these systems is
critical to performance, we have included requirements for daily
verification of the adsorber valve sequencing and cycle time. This
daily system check will ensure that the adsorber is operating with
proper valve sequencing and cycle time.
    While adsorption systems can achieve high levels of efficiency for
removal of organic compounds from vent streams, performance degrades
over time as the adsorption media deteriorates or becomes fouled.
Because of this known performance deterioration, and because there are
many mechanical elements in the system which can cause performance
problems, we are proposing weekly measurements of the adsorber bed
outlet VOC or regulated material concentration over the last 5 minutes
of an adsorption cycle for each adsorber bed. These measurements are
not meant to be a check against the emissions limit established by the
referencing subpart; rather, it is a check to determine if the absorber
performance is deteriorating and/or has deviated from typical
operation. By conducting weekly checks, the owner or operator will
establish knowledge of typical operating conditions, so that if
performance does degrade, it will become clear based on changes in the
weekly measurements. We are proposing that the owner or operator
establish a maximum normal concentration to compare to the weekly
measurements. If a measurement is obtained that is above the maximum
normal concentration, a corrective action process must be initiated
within 8 hours. We are proposing that you must develop a corrective
action plan that includes investigation of the adsorbent and its
efficacy, the valve sequencing system and regeneration process, and
additional monitoring, as well as site-specific corrective actions
appropriate to the system. This plan is not required to be submitted to
the Administrator for approval, but is required to be kept as a record
per the requirements of proposed 40 CFR 65.742(j)(1).
    Measurements for the weekly checks on each adsorber may be taken
with a portable analyzer using Method 21 of 40 CFR part 60, appendix A-
7 for open ended lines, or using chromatographic analysis. Acceptable
levels for end-of-cycle measurements, the maximum normal concentration
will be established based on a statistical evaluation of the last 5
minutes of at least eight adsorption cycles for each adsorber. Because
these measurements are taken in the last 5 minutes of the adsorption
cycle, they indicate the worst-case emissions over the adsorber cycle.
Therefore, they are not indicators of compliance with the emission
limit, but instead are indications of non-normal operation, which
trigger a corrective action. An adsorber would not be considered to be
in deviation unless three consecutive weekly measurements are taken
that are above the maximum normal concentration; if the requirement to
initiate corrective action within 8 hours is not met; or if a weekly
measurement is not performed. See section VII of this preamble for a
discussion of the economic and cost impacts of these requirements.
    Because the materials desorbed during the regeneration process are
regulated materials and are either recovered or disposed of, we are
proposing explicit requirements to treat the regulated materials
extracted from a regenerative system as process wastewater or vent
streams subject to control, as specified by the referencing subpart.
    Very few previously published rules have addressed adsorption
systems, which are not regenerated onsite. Because there is wide
application of non-regenerative adsorption systems, we are including
provisions for these systems in the proposed rule. For clarity, we have
differentiated the proposed requirements for absorbers generated onsite
and the requirements for non-regenerative adsorbers or

regenerative adsorbers that are regenerated offsite in separate
sections.
    As a guideline for the proposed monitoring, we used the National
Emission Standards for Site Remediation (40 CFR part 63, subpart
GGGGG), as well as monitoring approaches approved by the EPA in
alternative requests for monitoring and in enforcement actions to
address historical compliance issues with non-regenerated adsorbers. We
are proposing CEMS monitoring for the adsorber exhaust. Alternatively,
we are proposing requirements for dual adsorbent beds in series and
daily monitoring. We have prescribed a dual bed system because the use
of a single bed does not ensure continuous compliance unless the bed is
replaced significantly before breakthrough. A dual bed system will
allow one bed to be saturated before it is replaced and, therefore,
makes efficient use of the adsorber bed without exceeding the emission
limits. Facilities utilizing non-regenerative adsorbers must typically
replace the adsorber bed at the end of the absorbent life and already
have a second bed onsite. Therefore, we have determined that these
requirements would not impose a cost increase; it would only require a
second adsorber bed to be purchased earlier than it would have under
previous rules. In addition, once the second adsorber was purchased,
the source would need to purchase and install canisters at the same
rate they would have under previous rules. In fact, the source could
likely reduce costs over time because the adsorber beds can be used to
a greater saturation level without risking non-compliance. Under
current rules that do not require a second bed, sources must replace
the beds, based on temperature readings, the vendor's bed life
expectancy estimates or past history, and may replace the bed
prematurely in order to avoid non-compliance. The burden of purchasing
the initial additional adsorber bed, when compared to the large
increase in compliance assurance, is small.
    Similar to regenerative adsorbers, in order to monitor performance
deterioration, we are proposing measurements of VOC or regulated
materials using a portable analyzer or chromatographic analysis for
non-regenerative absorbers. We are proposing that these measurements be
taken daily on the outlet of the first adsorber bed in series using a
sample port. Furthermore, in order to relieve some monitoring burden,
we have included the option to reduce the frequency of monitoring with
the portable analyzer from daily to weekly or monthly. If you choose
this option, you would first be required to establish an average
adsorber bed life. For periods when more than 2 months remain on the
bed life, monthly monitoring can be conducted, and when more than 2
weeks remain on the bed life, weekly monitoring can be conducted. For a
discussion of the economic and cost impacts of these monitoring
requirements, see section VII of this preamble.
    Condensers. The proposed standards include requirements for
condensers used as control devices, which are based on the standards of
40 CFR part 63, subpart SS. Subpart SS requires that ``exit (product
side)'' temperature be monitored; the proposed rule clarifies that the
temperature of the ``condensate receiver'' be monitored. The proposed
standards require a design evaluation be conducted on condensers
instead of a performance test to demonstrate compliance. The
equilibrium calculation for condensers using the actual measured
temperature and a thorough understanding of the stream composition is
an accurate method for estimating emissions in the exiting gas stream
from a condenser. A performance test for condensers generally does not
provide additional information that equilibrium calculations would not
provide. Furthermore, requiring a design evaluation will reduce overall
costs for owners and operators who are referred to the Uniform
Standards for Control Devices. However, a performance test could be
required by the referencing subpart if it is determined to be more
appropriate for a given source category.
    As part of the design evaluation, we are proposing that you use the
engineering evaluation methodologies in 40 CFR 65.835(d) with the
temperature of the condensate receiver to determine the outlet organic
regulated material concentration. You would then be required to show
the concentration meets the emission standard established in the
referencing subpart, or to conduct additional calculations to
demonstrate a percent reduction or aggregate percent reduction for
batch process vents in a referencing subpart was being met.
    In the design evaluation for condensers, we have included a
provision to consider conditions under which entrainment of the
condensing liquid could occur, as well as the other operating
conditions traditionally included in a condenser design evaluation,
such as the vent stream flow rate, relative humidity and temperature.
Entrainment is an important factor in condenser performance that should
be considered in a design evaluation in order to document that the
condenser achieves the required emission reduction from a referencing
subpart.
    Biofilters. We are proposing standards for biofilters used as
control devices in proposed 40 CFR 65.748. We are providing these
requirements as an additional control option for the Uniform Standards
for Control Devices in order to add flexibility for industry.
Compliance requirements for biofilters were included in a final
amendment to the MON (71 FR 40333, July 14, 2006) as a response to
comment by commenters. The final amendments specified that biofilters
are an option for complying with the 95-percent reduction emission
limit for batch process operations. A biofilter control option was not
made available for continuous process operations in the MON because of
concerns that biofilters could not meet the 98-percent control
efficiency standard for continuous process operations. We are proposing
biofilters as a control option for both batch and continuous process
operations if you can demonstrate compliance with the emission
limitation or percent reduction required by the referencing subpart. We
are proposing you install a CEMS capable of measuring regulated
materials, or you may install a temperature CPMS for the biofilter bed.
    In biofiltration, microbial activity is the primary means by which
the process stream is controlled; the effectiveness of the device is
maximized by maintaining preferential conditions for the growth of
appropriate microbes. Temperature is a significant factor affecting the
growth and maintenance of healthy microbes within the bed--temperatures
that are too high or too low will result in reduced microbe colonies
and reduced performance for the bed. It is also a good indicator of the
health of the microbes since healthy microbes will generate heat
themselves. Therefore, we are requiring bed temperature monitoring to
ensure that the biofilter can achieve and maintain the emission limits
specified in the referencing subpart. For a discussion of the economic
and cost impacts of these requirements, see section VII of this
preamble.
    Given the concerns expressed in the preamble to the final MON rule
regarding continuous process operations, we are also proposing
requirements to monitor the moisture content of the biofilter bed and
pressure drop through the biofilter bed to ensure that the biofilter
can achieve the emission limit or percent reduction requirements of the
referencing subpart. The moisture content of the biofilter bed

is another indicator of the health of microbes. Pressure drop through
the biofilter bed is important to ensure the filter bed is not plugged.
    In lieu of these additional monitoring requirements, we are also
considering requiring weekly measurements of VOC or regulated material
at the outlet of each biofilter bed using a portable analyzer or
chromatic analyzer to monitor performance deterioration, similar to
those requirements proposed for adsorbers. We are soliciting comment,
including the identification or submittal of information or data, as to
whether biofilter bed temperature monitoring would be enough for
continuous compliance demonstration. Additionally, we are soliciting
comments and supporting data or studies that assess the effectiveness
of measuring additional parameters to ensure performance and
compliance.
    The MON does not allow a design evaluation to demonstrate
compliance for biofilters; however, we have included provisions for a
design evaluation if the referencing subpart allows one. A design
evaluation for a biofilter may be adequate to demonstrate compliance
for certain source categories; however, this will need to be considered
on a source category-specific basis and justified in the referencing
subpart rulemaking.
    Sorbent injection and collection systems. In order to provide
additional control technologies that will expand the options for future
rulemakings, we are proposing requirements for sorbent injection
systems that remove pollutants from exhaust gas. Sorbent injection is
an emissions control technique that was developed to reduce pollutants
from exhaust gas, primarily from combustion sources. The sorbent
injected into the gas stream may be activated carbon, lime or any other
type of material injected into a gas stream for the purposes of
capturing and removing regulated materials.
    Activated carbon is used in sorbent injection systems where control
of mercury or dioxin and furan emissions is required. Lime or other
sorbents may also be used in sorbent injection systems to remove acid
gasses, such as hydrochloric acid or sulfuric acid. Sorbent injection
is used in conjunction with a filtration device designed to collect the
sorbent after injection.
    As a basis for developing the proposed rule, we have adapted the
requirements for sorbent injection systems that were included in the
final rule for National Emission Standards for Hazardous Air Pollutants
from the Portland Cement Manufacturing Industry (75 FR 54970, September
9, 2010). This recent NESHAP determined monitoring and performance
specification requirements for sorbent injection systems and carrier
gas systems that reflect the latest technical developments for these
control options. In addition, facilities complying with the proposed
provisions for sorbent injection would also be required to meet the
requirements for fabric filters in proposed 40 CFR 65.762. The Portland
Cement NESHAP requires facilities to specify and use the brand and type
of sorbent used during the performance test until a subsequent
performance test is conducted. We are proposing that you would be
required to test if you wanted to substitute a different brand or type
of sorbent. Although the Portland Cement NESHAP allows an owner or
operator to substitute different brands or types of sorbent without
having to do a new performance test (provided that the replacement has
equivalent or improved properties compared to the sorbent used in the
previous performance test), we have modified the proposed standards to
require a new performance test if the sorbent is replaced with a
different brand and type of sorbent than was used in the most recent
performance test. As we intend the Uniform Standards for Control
Devices to be referenced in both NSPS and NESHAP rulemakings across
multiple source categories, this change ensures that the control device
will continue to meet the emission limits or percent reduction
requirements of a referencing subpart when a change of sorbent occurs.
A referencing subpart may override this retest requirement if it is
determined in its rulemaking to be unnecessary for the source category
being regulated.
    Provisions for a design evaluation for sorbent collection systems
are proposed for this rule in the event that a referencing subpart
allows a design evaluation to be conducted in lieu of a performance
test. Because this is a relatively new control technology, there were
no current rules that provided guidance for a design evaluation of a
sorbent collection system. Therefore, we have developed the proposed
requirements using recently published articles on activated carbon
injection as a control technology. This research indicates that the
parameters identified in proposed 40 CFR 65.760(d) provide the best
evaluation of sorbent injection system performance.
    Other control or devices. We have incorporated requirements for
performance testing and the development of monitoring requirements on a
case-by-case basis in order to address control devices that may be used
by industry, but are not described specifically in this rule. These
requirements are unchanged from the current provisions of 40 CFR part
63, subpart SS. Additionally, if other major control devices are used
in specific source categories as a primary means for control, the
referencing subpart can lay out such requirements needed in order to
demonstrate compliance.
4. How did the EPA determine requirements for fuel gas systems?
    In consideration of our experience implementing previous rules
addressing fuel gas systems as control devices, we are proposing
updated standards that clarify the definition of fuel gas system and
ensure that these systems are achieving good combustion and control.
Under 40 CFR part 63, subpart SS, owners and operators are permitted to
route vent streams from storage tanks, transfer equipment and equipment
leaks to a fuel gas system as a method of control (this compliance
option is not specifically provided for process operations). Fuel gas
systems are considered a part of the process, therefore process vent
streams that are routed to a fuel gas system are not considered vent
streams requiring control because they are not released to the
atmosphere. The proposed rule does not specifically state that this
control option is only for equipment leaks, storage tanks and transfer
operations emissions. It is not necessary to allow this option for only
some of the emission unit types, given that the proposed Uniform
Standards may be referenced in future NESHAP and NSPS for multiple
source categories and industry types, and those rulemakings can
determine whether to restrict the control options for specific types of
emission units.
    As previously discussed for small boilers and process heaters in
section V.B.3 of this preamble, small boilers or process heaters
receiving vent streams subject to subpart M with a capacity less than
44 MW (in which the vent stream is introduced with combustion air or as
a secondary fuel) would be subject to the requirements of proposed 40
CFR 65.724, whether they are part of a fuel gas system or not. If your
fuel gas system directs the vent stream to small boilers or process
heaters, you would still be required to meet the performance testing
and monitoring requirements for small boilers and process heaters. As
discussed in section V.B.3 of this preamble, larger boilers and process
heaters in which the vent gas stream is introduced with or as the
primary fuel have been recognized as units that can be confidently
assumed to achieve good combustion. There is not

the same confidence in the performance of small boilers and process
heaters; therefore, we are proposing that the units be tested and
continuously monitored.
    We expect, in most cases, the vent gas stream of fuel gas systems
will be introduced as the primary fuel and/or will be routed to larger
units. We want to continue to encourage the use of this otherwise waste
gas. However, if small boilers and process heaters are attached to the
fuel gas system, then you would be required to conduct performance
testing and monitoring. We do not expect this scenario to be common. We
also considered defining a fuel gas system such that the vent gas must
be introduced with or as a primary fuel, but determined that this would
reduce flexibility for sources.
    Under the proposed standards, all fuel gas systems that are in
regulated material service must perform quarterly LDAR monitoring and
would be required to meet the applicable provisions of proposed 40 CFR
part 65, subpart J (see section IV.A of this preamble) as they apply to
the individual equipment components that comprise the fuel gas system.
We are proposing these requirements to ensure that a vent stream in
regulated material service is properly routed by the fuel gas system
and delivered to the combustion device for destruction. We expect that
most fuel gas systems meet the applicability of the LDAR requirements
and are already conducting LDAR monitoring; therefore, these
requirements are not expected to introduce a new or unnecessary
regulatory burden for industry.
    The proposed standards revise the definition of fuel gas system to
include the requirement that the fuel in the fuel gas system be
nonhalogenated. It is common for chemical sector rules to include a
prohibition on combustion of halogens and a requirement for hydrogen
halides or halogen reduction after combustion. However, this
requirement was not explicit for vent streams routed to a fuel gas
system under previous rules, and it is not our intent to allow
halogenated streams to be combusted without additional control. Because
fuel from fuel gas systems can be used in any number of combustion
sources, hydrogen halide and halogen reduction after combustion is less
likely to be feasible. Additionally, because process vent streams could
be routed to the fuel gas system and not be subject to the rule, yet
could still contain significant amounts of halogens, we are proposing
this definition change to ensure that HAP are not created through the
combustion of a regulated material.
5. How did the EPA determine the proposed requirements for fabric
filters?
    We have incorporated requirements for fabric filters in subpart M
with the intent to simplify future rulemakings that would refer to the
Uniform Standards. The proposed monitoring, recordkeeping and reporting
requirements may be referenced by new or revised NSPS or NESHAP that
would establish standards for PM or other regulated materials
controlled by fabric filters and not previously covered by other
consolidated rulemakings. As such, the consolidation of fabric filter
requirements in subpart M facilitates more efficient rulemaking and
ensures consistent standards for these control devices across multiple
source categories. The monitoring, design evaluation and recordkeeping
and reporting requirements for fabric filters were modeled after the
Pesticide Active Ingredient Production NESHAP (40 CFR part 63, subpart
MMM, as referenced by the MON) and the final rule for National Emission
Standards for Hazardous Air Pollutants from the Portland Cement
Manufacturing Industry, published on September 9, 2010 (40 CFR part 63,
subpart LLL, 75 FR 54970). The proposed requirements include the
installation of a bag leak detection system equipped with an alarm that
will sound when an increase in relative PM emissions over a preset
level is detected.
    The Portland Cement Manufacturing NESHAP required that the bag leak
detection system be certified by the manufacturer to be capable of
detecting PM emissions at concentrations of 10 milligrams per actual
cubic meter (mg/acm) or less. Because we intend the proposed Uniform
Standards to be applicable for the majority of source categories
complying with MACT, we considered that there may be future rulemakings
that need to specify lower PM emission limits and would require a lower
allowable detection limit for the bag leak detectors. Based on vendor
literature, modern bag leak detection systems are capable of detecting
baseline emissions as low as 1 mg/acm (see, Fabric Filter Bag Leak
Detection Guidance, EPA-454/R-98-015, September 1997, incorporated by
reference). Therefore, we are requiring that the bag leak detection
system be certified at a detection level of 1 mg/acm or less. This
requirement may be overridden by a referencing subpart in future
rulemakings, as appropriate, based on the specific needs of the source
category.
    We have also added a provision previously included in the Major
Source Industrial, Commercial, and Institutional Boilers and Process
Heaters NESHAP (76 FR 15608, March 21, 2011), requiring that the bag
leak detection system must be operated and maintained such that the
alarm does not sound more than 5 percent of the operating time during a
6-month period. We are requiring records of the total alarm time and
corrective actions taken following an alarm sounding for demonstration
of compliance. These requirements are operation and maintenance
requirements that could be adopted in future rulemakings to ensure that
the fabric filter is being operated at the conditions for which the
control device is meeting the emission limit specified in the
referencing subpart.
    Additionally, the proposed rule requires that you conduct a
performance test on your fabric filter, but provisions have been
included for those situations where a design evaluation is acceptable
and allowed by the referencing subpart (see sections V.A.9 and V.B.8 of
this preamble).
6. How did the EPA determine the performance testing requirements?
    The performance testing requirements that we are proposing are
modeled after specific requirements from 40 CFR part 63, subpart SS,
which are based on performance testing requirements previously
developed by the EPA for use in implementing standards that could apply
to a variety of chemical industry sources.
    We have organized the performance testing requirements to group
similar topics together, and added new methods for performance testing
to develop a more generic and inclusive set of control requirements
that may be easily referenced in future rulemakings. In addition to
using the term ``regulated material'' (see General differences between
proposed 40 CFR part 65, subpart M and 40 CFR part 63, subpart SS at
the beginning of section V.B of this preamble), we are proposing
performance testing requirements that reflect this broader range of
pollutants.
    Although based on language from 40 CFR part 63, subpart SS, where
we propose that you conduct all performance tests at maximum
representative operating conditions for continuous process operations,
we have defined maximum representative operating conditions to be those
conditions that result in the most challenging condition for the
control device. In an effort to provide more flexibility to owners and
operators regarding the identification of the

proper testing conditions, the most challenging condition for the
control device may include, but is not limited to, the highest HAP mass
loading rate to the control device, or the highest HAP mass loading
rate of constituents that approach the limits of solubility for
scrubbing media. The EPA understands that there may be cases where
efficiencies are dependent on other characteristics of emission
streams, including the characteristics of components and the operating
principles of the devices. For example, the solubility of emission
stream components in scrubbing media, or emission stream component
affinity in carbon adsorption systems can also define the most
challenging condition for a particular control device.
    For batch process operations, we are proposing consistent
requirements to those in 40 CFR part 63, subparts GGG and FFFF, and are
requiring that you develop an emissions profile and conduct your
performance test at absolute worst-case conditions or hypothetical
worst-case conditions. Although continuous operations tend to have
products and operations that remain relatively constant, the control
devices for batch operations may be subject to a wide variability of
products and emission stream characteristics, and a performance test at
``maximum representative'' conditions for batch operations may not be
representative at a later date when the products have changed. Absolute
worst-case conditions are based on an emissions profile that shows
periods of time when the maximum load, the regulated material loading
or stream composition (including non-regulated material) is the most
challenging condition for the final control device. To provide
flexibility for sources, we are also proposing that you may test under
hypothetical worst-case conditions as an alternative. Hypothetical
worst-case conditions are simulated test conditions that, at a minimum,
contain the highest hourly load of regulated material emissions that
would be predicted to vent to the final control device, based on an
emissions profile.
    The agency's intent, when requiring the development of an emissions
profile, is to determine the maximum HAP loading to a control device
over time. Therefore, the proposed rule requires that the emissions to
the device be evaluated by plotting HAP emissions versus time. To
provide multiple options for compliance, we have allowed for the
emission profile to be determined by process, by equipment or by
capture and control device limitation (this would be dependent on how
you choose to characterize your worst-case conditions). When sources
test under worst-case conditions, this reduces, and may eliminate, in
some cases, the need for any retesting at a later date when conditions
change. If a source tested under normal operating conditions, then any
change from these conditions would trigger a need to retest the source
under the revised normal operating conditions. The concept of worst-
case conditions allows sources to anticipate potential changes so that
only one (initial) test is generally required, which would reduce the
burden on the source. We note that the referencing subpart could
require a re-test (e.g., annual or every 5 years) if it is appropriate
to demonstrate compliance for a given source category; this would be
determined during the rulemaking process for the referencing subpart.
    Building off the requirements of 40 CFR part 63, subpart SS, the
MON uses a hierarchy to determine applicable requirements for combined
emission streams in 40 CFR 63.2450(c)(2). For example, the MON allows
you to comply with only the batch process operation requirements for
combined batch and continuous process operations. However, for the
proposed rule, we are not establishing a hierarchy because the
referencing subpart must consider the applicable statutory requirements
for the specific type of rulemaking (CAA section 111 or section 112).
Instead, we are proposing that you must meet all requirements for each
emission stream type in a combined emission stream (i.e., both
continuous and batch process operation requirements must be met). The
proposed rule is written in this way to ensure compliance for each
emission stream. A hierarchy may be appropriate for certain source
categories; however, this will need to be considered on a source
category-specific basis during the development of the referencing
subpart. A referencing subpart can override specific requirements in
the Uniform Standard, as appropriate.
    We are proposing that if you make a change to process equipment or
operating conditions that would affect the correlation between the
operating parameter values of a control device and the emission
reduction performance of that control device, and would render the
previously established operating limits ineffective, you must conduct a
performance test within 180 days of the date of startup of the change.
This performance test would be necessary to establish new operating
limits and demonstrate that you are in compliance with the applicable
emission limit of the referencing subpart. For instance, a facility
could institute changes that increase the mass flow to a thermal
oxidizer, requiring a higher operating limit for temperature to
maintain compliance with the emission standard of the referencing
subpart. This proposed requirement is necessary to ensure that the
control device remains effective for compliance with the referencing
subpart.
    We have consolidated the allowed test methods in Table 5 of subpart
M for ease of reading. The proposed rule provides test methods based on
the types of emissions limits that we anticipate would be specified in
a referencing subpart. As was done in the MON (for gas streams
containing formaldehyde) and in the Pharmaceuticals Production NESHAP
(for gas streams containing carbon disulfide), we have provided
specific test methods for determining compliance when formaldehyde or
carbon disulfide makes up a significant portion of the vent stream.
Consistent with our previous determinations under these rules, we have
ascertained that not all methods detect these compounds accurately and
these specific methods are necessary in the proposed Uniform Standards.
    We also are proposing that you may use Method 320 of 40 CFR part
63, appendix A as an alternative to using Method 18 or Method 26/26A of
40 CFR part 60, appendices A-6 through A-8, to determine compliance
with a specific organic regulated material compound outlet
concentration or percent reduction emission limit, or a hydrogen halide
emission limit specified in the referencing subpart. In response to a
public comment, the Method 320 of CFR part 63, appendix A option was
added to the MON at final promulgation (68 FR 63852, November 10,
2003). The EPA declared that Method 320 of CFR part 63, appendix A was
an acceptable method to demonstrate compliance for any type of batch or
continuous vent stream. We have augmented this provision by specifying
that EPA Method 320 may only be used to demonstrate compliance with a
halogen emission limit if you can show that there are no diatomic-
halogen molecules present in the vent stream being tested. For vent
streams with diatomic-halogens molecules, we have determined that EPA
Method 18 and EPA Method 26/26A are more effective. In addition, we are
not allowing EPA Method 18, ASTM D6420-99 and EPA Method 320 to test
for total regulated material because these methods only work for
determining the quantity of known pollutants; therefore, you could

fail to identify the ``total'' regulated material.
    Because a referencing subpart may have requirements for organic HAP
and metal HAP, or requirements for use of a surrogate, such as PM or
fine particulate matter (PM2.5) for metal HAP, we have
incorporated provisions from the MON that tell you how to determine
compliance with a PM or PM2.5 emission limit specified in a
referencing subpart. (As discussed in section II.C of this preamble,
the referencing subpart would establish and provide rationale for the
use of a surrogate.) As determined under the MON, Method 29 of 40 CFR
part 60, appendix A-8 allows you to determine the quantity of each HAP
metal at the inlet and outlet of the control device(s). Furthermore,
the MON allows for a second option, since controls for PM would also
control the HAP metals, to use Method 5 of 40 CFR part 60, appendix A-3
to determine the quantity of PM at the inlet and outlet of the control
device(s). We are proposing Methods 201A and 202 at 40 CFR part 51,
appendix M, or, if the stack contains entrained water droplets (e.g.,
immediately after a wet scrubber), Method 5 at 40 CFR part 60, appendix
A-3 and Method 202 for total PM2.5. We have determined that
EPA Methods 201 and 202 are more accurate for measurement of
PM2.5. It is our determination that the methods proposed
represent the best and most recent methods for measurement of HAP, VOC,
PM and PM2.5.
7. How did the EPA determine the requirements for batch processing
operations?
    We are proposing language from the MON and the Pharmaceuticals
Production NESHAP (40 CFR part 63, subpart GGG) to accommodate batch
process operations. The MON primarily references the batch process
operation provisions in the Pharmaceuticals Production NESHAP. The
proposed standards are intended to be referenced from multiple
regulations representing different source categories, and do not set
group determinations or levels of control.
    We have included provisions in proposed 40 CFR 65.826 and 40 CFR
65.827 explaining how compliance should be demonstrated for the
different emission limit formats that a referencing subpart may use for
batch process operations. The language accommodates percent reduction
or outlet concentration limits for control devices. We have included
the emission limit format from the MON that requires the owner or
operator to show compliance with a percent reduction by aggregating
emissions over the full batch process. These requirements would apply
only when a referencing subpart requires the owner or operator to show
compliance with a percent reduction using this method (see section
V.A.8 of this preamble). We have included language (see equations 29
through 31 of proposed 40 CFR 65.835(a)) clarifying how to determine
compliance with a percent reduction where a referencing subpart
requires the owner or operator to aggregate batch emissions. The
equations illustrate how you would compare the sums of the controlled
and uncontrolled emissions for all batch process operations subject to
control within the process to calculate the percent reduction achieved.
This is a clarification of the MON language, which stated that
uncontrolled and controlled emissions should be compared to demonstrate
compliance, but did not provide additional details to explain how this
should be done.
    We are proposing engineering evaluation methodologies that are
incorporated by reference from section 3 of the EPA's Emissions
Inventory Improvement Program, Volume II: Chapter 16, Methods for
Estimating Air Emissions from Chemical Manufacturing Facilities, August
2007, Final, (EPA Emissions Inventory Improvement Program (EIIP) Volume
II: Chapter 16). These methods are similar to those used in the
Pharmaceuticals Production NESHAP, but include some refinements, such
as an iterative methodology for purging, or gas sweep of a partially
filled vessel emission episode. EPA EIIP Volume II: Chapter 16 also
contains additional methodologies (that were not included in the
Pharmaceuticals Production NESHAP) for calculating emissions from
charging to a partially filled vessel with miscible contents, and
evaporation from an open top vessel or spill. We are proposing that you
conduct an engineering assessment to calculate uncontrolled emissions
from other emissions episodes not described in EPA EIIP Volume II:
Chapter 16. We are soliciting comment on the proposed use of EPA EIIP
Volume II: Chapter 16.
8. How did the EPA determine the requirements for compliance through
design evaluation?
    With the exception of condensers, the proposed standards under
subpart M require performance testing to demonstrate compliance with
the applicable standard. However, to provide flexibility, we are
including requirements for a design evaluation that could apply to non-
flare control devices if it is allowed by the referencing subpart. For
condensers, we are proposing that you must conduct a design evaluation
(see discussion for condensers in section V.B.3 of this preamble).
    Subpart M is structured such that general requirements for
conducting a design evaluation are included under one section (proposed
40 CFR 65.850). More specific requirements pertaining to information
that must be included in the design evaluation for each type of device
are included in the corresponding section for that control device. The
requirements for determining the components to include in a design
evaluation are based on 40 CFR part 63, subpart SS, which were
previously developed by the EPA for use in implementing a generic set
of control standards that could be applied for multiple source
categories. To ensure that sources can demonstrate compliance with the
referencing subpart, we are proposing that you must prepare both a
monitoring description and design evaluation. The monitoring
description provides documentation that the source is maintaining the
continuous monitoring equipment such that the control device can meet
the emission limits specified in the referencing subpart. For the
monitoring description, you would be required to choose the parameters,
the operating limit(s), the monitoring frequency and the averaging time
for each operating parameter, based on site-specific information,
manufacturer's specifications, engineering judgment or other
significant information. Your design evaluation would include
documentation demonstrating that the control device being used achieves
the required emission limit of a referencing subpart, taking into
account the composition of the vent stream entering the control device,
flow and regulated material concentration. There were no changes made
to the design evaluation provisions except for the changes to: (1)
Small boilers and process heaters, (2) oxidizers regarding the minimum
temperature and residence time and (3) the inclusion of a design
evaluation for biofilters when allowed by the referencing subpart (see
previous discussion in section V.B.3 of this preamble).
9. How did the EPA determine the required records and reports for this
proposed standard?
    The notification, recordkeeping and reporting requirements that we
are proposing are similar to those required in 40 CFR part 63, subpart
SS. However, we have streamlined the periodic

compliance reporting with title V semiannual reporting requirements,
incorporated updates for clarification, left out provisions that are
redundant or unnecessary and created recordkeeping and reporting
requirements to address any monitoring requirements included in the
Uniform Standards. Many of these details are discussed in section
VI.B.6 of this preamble.
    Averaging Periods. We are proposing records of the daily or
operating block average (for batch operations) value of each
continuously monitored parameter or emissions.
    Although some regulations under 40 CFR part 60 and 40 CFR part 61
require 3-hour averaging (e.g., the SOCMI Air Oxidation NSPS, 40 CFR 60
Subpart III; the SOCMI Distillation Operations NSPS, 40 CFR 60 Subpart
NNN; and the SOCMI Reactor Processes NSPS, 40 CFR 60 Subpart RRR), many
of the part 63 regulations require daily averages. Specifically, with
the exception of the recently proposed polyvinyl chloride and
copolymers (PVC) rule (40 CFR 63, subpart J for PVC Production; 76 FR
29528, May 20, 2011), which requires 3-hour averaging, daily averaging
periods are used in all past part 63 NESHAP affecting the chemical and
refining sectors. Therefore, the EPA has decided to allow daily
averaging for all control devices, unless otherwise provided under a
referencing subpart.
    We also do not consider daily averaging a relaxation of the
previous NSPS that currently require more frequent averaging.
Specifically, the 3-hour averages in NSPS and the daily averages in
part 63 should not be compared only considering the averaging time, but
one should also consider the meaning of out-of-range results. Under the
NSPS, an out-of-range 3-hour average does not necessarily mean the
source is out of compliance. Under the 40 CFR part 60 General
Provisions, compliance with emission standards is determined by a
performance test (see 40 CFR 60.11(a)). Under the 40 CFR part 63
General Provisions, it is clear that deviations from monitoring
parameter ranges are direct violations (see 40 CFR 63.6(e)).
    Under the proposed Uniform Standards, we have adopted the
significance of out-of-range results from 40 CFR part 63; therefore, an
out-of-range parameter on a daily average basis is a violation. We
would allow the same out-of-range parameter determinations from 40 CFR
part 63 to be made in all referencing subparts, including regulations
under 40 CFR part 60 and 40 CFR part 61. Therefore, although facilities
from 40 CFR part 60 or 40 CFR part 61 referenced to the Uniform
Standards may become subject to daily averages in lieu of 3-hour
averages, they would also be considered out of compliance if the daily
average is out of range, provided this change is adopted in the
rulemaking for the referencing subpart.
    We anticipate that the referencing subpart may ``override'' the
proposed daily averaging period with a stricter requirement if it is
determined that such a requirement would be necessary to maintain the
emission standard for the source category covered by the referencing
subpart. A good example of such a source category is the proposed PVC
Production NESHAP. It was determined for proposal that, for this source
category, 3-hour averages are necessary to meet MACT. We consider the
development of a referencing subpart at the appropriate time to make
these source-category specific decisions.
    We are proposing that you must report the daily and operating block
averages for each continuously monitored parameter as part of the
semiannual periodic report submitted through the CEDRI (see section
II.F of this preamble). The EPA relies on the submittal of performance
test data and emissions and parametric monitoring data to conduct
effective reviews of CAA sections 111 and 112 standards, as well as
compliance determinations, emission factor development, residual risk
assessments and technology reviews. These emissions averages and
parameter averages could supply up-to-date information regarding the
capabilities of current industry technology, identify compliance issues
and supplement emissions test data for establishing emission factors,
improving regulation and improving the quality of emission inventories.
Collecting this data on an ongoing basis through CEDRI will greatly
reduce or eliminate the burden to industry and EPA from ICR efforts.
    Recordkeeping and reporting of batch operations. The recordkeeping
and reporting requirements for batch operations were modeled after the
MON (40 CFR part 63, subpart FFFF) and Pharmaceuticals Production
NESHAP (40 CFR part 63, subpart GGG). 40 CFR Part 63, subpart SS, as
promulgated, contains only provisions for combined continuous and batch
operations. We have drawn the requirements from 40 CFR part 63,
subparts GGG and FFFF because these NESHAP contain and clarify
technical requirements for batch process operations; in particular, the
MON improves upon some of the technical requirements of the
Pharmaceutical Production NESHAP and reflects a set of standards that
both industry and the EPA have experience in implementing. The
inclusion of requirements for batch operations allows the proposed
Uniform Standards to accommodate a wider range of source categories.
The proposed recordkeeping and reporting requirements reflect our most
current survey of batch operations under 40 CFR part 63, subparts GGG
and FFFF.
    The proposed subpart M includes a pre-compliance report for batch
processes, as does the MON and Pharmaceuticals Production NESHAP. This
report is a combination of data submittals and reports that require the
EPA review and approval prior to implementation and is, therefore, due
before the compliance date (6 months prior to the compliance date for
existing sources and to be submitted with the application for approval
of construction or reconstruction for new sources). While we have
designed the requirements for batch process operations to provide
flexible options for compliance for owners and operators, we must
ensure compliance with the MACT, GACT and BSER standards specified in
the referencing subpart. We contend that the pre-compliance report is a
valuable tool for the regulatory agency responsible for making
compliance determinations. The batch pre-compliance requirements
include providing details on the test conditions, data, calculations
and other information used to establish operating limits for all batch
operations, and rationale for why each operating limit indicates the
control device is meeting the specified emission limit of the
referencing subpart during each specific emission episode. If you used
an engineering assessment, as specified in 40 CFR 65.835(b)(2), you
would also include data or other information supporting a finding that
the emissions estimation equations in the proposed subpart M are
inappropriate. These data would include very detailed site-specific
information and complex rationale for the selection of operating limits
and emissions calculations. It is important that such data are reviewed
prior to compliance to provide time to revise the CEMS performance
evaluation and monitoring plan or the CPMS monitoring plan and conduct
any necessary onsite preparation for revised monitoring requirements,
based on the EPA concerns prior to the compliance date. This will
ensure that there are no periods of noncompliance resulting from
selection of an unacceptable approach. In the proposed Uniform
Standards, we are using the term ``batch pre-compliance report'' rather
than

``pre-compliance report'' because the report is submitted for only
batch processes and includes only the batch information listed in this
paragraph.
    There are several items required in the pre-compliance report for
the two previous NESHAP that are not proposed in subpart M because they
are not related to the control devices covered by this proposed rule.
For example, we are not proposing requirements to determine wastewater
characteristics, as required by the Pharmaceuticals Production NESHAP,
because we are not proposing requirements for wastewater facilities at
this time.
    Several source categories, including the Miscellaneous Organic
Chemical Manufacturing source category and the Pharmaceuticals
Production source category, use non-dedicated, multipurpose equipment
that may be configured in numerous ways to accommodate different batch
processes. We anticipate that when a NSPS or NESHAP considers
referencing subpart M for a batch process operation, there could be a
need to anticipate alternate operating scenarios for the batch process.
As such, we are proposing these requirements in subpart M in order to
accommodate these alternate scenarios.
    Fabric filter recordkeeping and reporting. We modeled the
recordkeeping and reporting requirements for fabric filters after the
Pesticide Active Ingredient Production NESHAP and the Portland Cement
Manufacturing NESHAP. These rulemakings reflect previous EPA
determinations for fabric filter control. We considered, but are not
proposing, that pre-compliance information be submitted for these
control devices. In particular, the Pesticide Active Ingredient
Production NESHAP and MON require an operation and maintenance plan and
corrective action plan be submitted as part of a pre-compliance report.
Instead, we are proposing that each bag leak detection system must be
installed, operated, calibrated and maintained in a manner consistent
with the manufacturer's written specifications and recommendations, and
in accordance with the guidance provided in EPA-454/R-98-015, September
1997. Therefore, we feel it is not necessary to pre-approve the fabric
filter plans when these requirements are followed. A future referencing
subpart may require prior approval if it is determined that it is
appropriate for a given source category and considering the applicable
statutory requirements for the specific rulemaking (e.g., MACT, GACT
and/or BSER standards), or we may choose to adopt separate requirements
for a particular source category in a referencing subpart. We are
proposing that the operation and maintenance plan and corrective action
plan for fabric filters be submitted as part of the Notification of
Compliance Status Report instead of a pre-compliance report. The
manufacturer's guidance and the EPA guidance document provide adequate
information for owners and operators to prepare appropriate operation
and maintenance and corrective action plans. We anticipate that fabric
filter operation does not vary enough to require site-specific pre-
review of these documents, although a referencing subpart may always
override these requirements for a given source category.

VI. Summary and Rationale for the Proposed Revision of 40 CFR Part 65
Uniform Standards General Provisions--Subpart H

    This section summarizes and provides rationale for the supplemental
proposal for 40 CFR part 65, subpart H. This subpart was originally
proposed on January 6, 2012 (77 FR 960). This supplemental proposal
generally adds new language and sections applicable to proposed
subparts H, I, J and M. There are some changes to the language
originally proposed, but these are relatively small changes needed to
incorporate the additional Uniform Standards subparts.
    In section VI of this preamble, the term ``we'' refers to the EPA
and the term ``you'' refers to owners and operators affected by the
proposed standards. All other entities are referred to by their
respective names (e.g., reviewing authorities.) Additionally, ``subpart
H'' refers to proposed 40 CFR part 65, subpart H.

A. Summary

    In a previous proposal of the National Uniform Emission Standards
for Heat Exchangers (40 CFR part 65, subpart L), signed by the EPA
Administrator on November 30, 2011 (77 FR 960, January 6, 2012), we
proposed general provisions in subpart H that would apply to all
sources subject to all Uniform Standards. In that proposal, we
specified that 40 CFR parts 60, 61 and 63, subpart A (i.e., referred to
in this preamble section VI as ``the 40 CFR parts 60, 61 and 63 General
Provisions'') would still apply as the General Provisions for the
Uniform Standards, with relatively minor additions in subpart H. During
development of proposed 40 CFR part 65, subparts I, J and M, we
reviewed this approach, in part under Executive Order 13563, Improving
Regulation and Regulatory Review, (see section II.A of this preamble
for further discussion of Executive Order 13563) to ensure that this
would be the best approach.
    Based on this review, we have determined that certain reporting
provisions in the 40 CFR parts 60, 61 and 63 General Provisions are not
consistent with each other (e.g., report names), and that these
differences could hamper efforts to provide compliance methods for all
sources under one part. Additionally, we have determined that some 40
CFR part 63 general provisions include more details (e.g., detailed
instructions for requesting a performance test waiver) that are not
provided for the same kind of provision in the 40 CFR parts 60 and 61
General Provisions (e.g., allowing a request for a performance test
waiver without detailed instructions). Applying these more detailed 40
CFR part 63 general provisions to sources covered under 40 CFR parts 60
and 61 would result in more clarity and would facilitate the compliance
process for sources regulated under 40 CFR parts 60 and 61 that refer
to the Uniform Standards.
    As such, we have concluded that the best approach to providing
general provisions for the 40 CFR part 65 Uniform Standards is to
consolidate some of the part 60, 61 and 63 general provisions, and to
include these consolidated general provisions in subpart H. For the
current proposal, we are issuing a supplemental proposal for subpart H
in order to include additional provisions applicable to all Uniform
Standards, as well as provisions applicable to individual Uniform
Standards in 40 CFR Part 65, Subparts I, J and M.
    For this purpose, we are maintaining five sections of subpart H
proposed on January 6, 2012 (77 FR 960), and adding 12 new sections. Of
the five previously proposed sections, we are proposing to make changes
to three sections, as follows: (1) 40 CFR 65.200 will refer to 40 CFR
65.210, which specifies which general provisions in subpart A of 40 CFR
parts 60, 61 and 63 apply to all Uniform Standards; (2) 40 CFR 65.265
will include additional methods incorporated by reference for 40 CFR
part 65, subparts I, J and M; (3) 40 CFR 65.295 will include additional
definitions of terms used in 40 CFR part 65, subparts I, J and M. The
12 new sections address the following consolidated general provisions
applicable to all Uniform Standards: (1) General requirements for
complying with the standards, operation and maintenance requirements,
recordkeeping and reporting; (2) how to

request a waiver for testing, recordkeeping and reporting or an
alternative monitoring, recordkeeping, test method or means of emission
limitation; and (3) authorities not delegated to the states.
    For those 40 CFR parts 60, 61 and 63 general provisions that would
apply to the Uniform Standards and that would not be consolidated into
subpart H, you are referred to Table 1 of subpart H, which lists the
sections or paragraphs of the 40 CFR parts 60, 61 or 63 general
provisions that still apply to the Uniform Standards. In general, Table
1 lists general provisions that are associated with applicability,
initial notifications and permit application requirements, and
requirements that are not the typical compliance provisions that a
source must meet. Examples of the types of 40 CFR part 60, 61 and 63
general provisions listed in Table 1 include: 40 CFR 60.2, 61.02 and
63.2 (definitions); 40 CFR 60.3, 61.03 and 63.3 (abbreviations); 40 CFR
60.12, 61.05, 61.19 and 63.4 (prohibited activities, circumvention and
fragmentation); and 40 CFR 60.5, 61.06 and 63.5 (determination of
construction or modification; preconstruction review and notification
requirements). Regulated sources subject to 40 CFR parts 60, 61 or 63
would remain subject to the provisions in Table 1, as applicable.

B. Rationale

1. What is the purpose of this subpart?
    40 CFR 65.200 is proposed to be changed from the previously
proposed 40 CFR 65.200 to specify that you would be required to comply
with the General Provisions, as specified in 40 CFR 65.210 (refers to
Table 1), as well as the referencing subpart.
2. Am I subject to the requirements of this subpart?
    40 CFR 65.205 is proposed to be added to subpart H to make it clear
who would be required to comply with the general provisions in subpart
H. Subpart H applies to owners and operators who are subject to a
referencing subpart and have been expressly directed to comply with the
Uniform Standards by a referencing subpart. This section is needed so
that you will understand the applicability.
3. When must I comply with this subpart?
    40 CFR 65.206 was added as part of efforts to make consistent the
organization of the Uniform Standards. The question of when to comply
is addressed in only subpart H.
4. Am I subject to the General Provisions for part 60, 61 or 63 of this
part?
    We are proposing to add 40 CFR 65.210 to subpart H to specify that
only some 40 CFR parts 60, 61 and 63 general provisions will apply to
you. As discussed in section VI.A of this preamble, we reviewed the 40
CFR parts 60, 61 and 63 General Provisions and concluded that the best
approach to providing general provisions for the 40 CFR part 65 Uniform
Standards is to consolidate some of the 40 CFR parts 60, 61 and 63
general provisions, and to include these consolidated general
provisions in 40 CFR part 65, subparts H and M. Consolidating these
provisions will allow us to streamline these general requirements for
the Uniform Standards, increasing the clarity of the General Provisions
and facilitating the compliance process for all parties. Consolidation
will also reduce administrative burden by facilitating our process of
amending the referencing subparts in the future.
    To consolidate the 40 CFR parts 60, 61 and 63 general provisions,
we reviewed each general provision in 40 CFR parts 60, 61 and 63. For
each provision, we determined if the general provision should be: (1)
Consolidated into one general provision in subpart H that applies to
sources complying with any Uniform Standard (you would not comply with
the original, unconsolidated part 60, 61 or 63 requirement); (2)
consolidated into one general provision in 40 CFR part 65, subpart M
that applies to sources complying with 40 CFR Part 65, subpart M (you
would not comply with the original, unconsolidated part 60, 61 or 63
requirement); (3) referred to in Table 1 to subpart H and required, as
specified in 40 CFR parts 60, 61 or 63; or (4) excluded from the
Uniform Standards because the provision does not apply to the types of
sources that will be regulated using the Uniform Standards (e.g.,
opacity and visible emissions provisions).
5. What are my general requirements for complying with operation and
maintenance requirements?
    Under 40 CFR part 60 and 40 CFR part 61, and as specified in
subpart A of both parts, compliance is demonstrated with an emission
limit using the results of a performance test; however, under 40 CFR
part 63, the General Provisions specify that the Administrator will
determine compliance based on performance tests, monitoring data,
records, operation and maintenance procedures, and conformance to the
procedures. In order to remove undue burden for individual source
categories and provide consistent requirements for sources complying
with the Uniform Standards, we have consolidated the general operation
and maintenance compliance provisions of 40 CFR part 63 in proposed 40
CFR 65.215. These proposed provisions were developed, based on 40 CFR
63.6(e), (f) and (g). The proposed provisions are different from 40 CFR
63.6(e), (f) and (g) in that they include changes in terminology and
cross-references, as well as removal of SSM provisions. The
consolidated provisions in 40 CFR 65, subparts H and M would apply to
all sources subject to referencing subparts.
    We have not included provisions for SSM in these Uniform Standards,
based on a recent District of Columbia Circuit ruling. The United
States Court of Appeals for the District of Columbia Circuit vacated
portions of two provisions in the EPA's CAA section 112 regulations
governing the emissions of HAP during periods of SSM. Sierra Club v.
EPA, 551 F.3d 1019 (D.C. Cir., 2008), cert. denied, 130 S. Ct. 1735
(U.S., 2010). Specifically, the Court vacated the SSM exemptions
contained in 40 CFR 63.6(f)(1) and 40 CFR 63.6(h)(1), that are part of
a regulation, commonly referred to as the ``General Provisions Rule,''
that the EPA promulgated under CAA section 112. When incorporated into
CAA section 112(d) regulations for specific source categories, these
two provisions exempt sources from the requirement to comply with the
otherwise applicable CAA section 112(d) emission standard during
periods of SSM.
    Consistent with Sierra Club v. EPA, the Uniform Standards, as
proposed, are designed to provide for continuous compliance with the
emission standards of a referencing subpart. Future rulemakings that
may reference the Uniform Standards will include a determination on the
need for separate standards for startup and shutdown for the specific
source category. Rationale for those provisions will be supplied at the
time of proposal, thus, providing an opportunity for public comment.
The final rulemakings for such referencing subparts would determine
whether separate standards for startup and shutdown would apply in lieu
of the otherwise continuously applicable referenced Uniform Standards.
6. What are my general recordkeeping requirements?
    We are proposing to add 40 CFR 65.220 to require that you maintain