for both grasslands and forest prescribed burning, while the general
time periods are similar from year to year in each State, the specific
burn timing necessarily varies based on meteorological and air quality
considerations each year. Consequently, the variability of the data
suggests that collecting it each year is consistent with the nature of
the activity which the EPA is seeking to collect data on.
    The EPA is considering both the date that States would report data
and which inventory year would be the first for any proposed
requirements. For the reporting date, the EPA is aware that State air
quality and forestry agencies are in a cycle of managing the current
fire season and preparing for the next fire season. In recent years, in
some areas, the fire season has become longer and less predictable,
which complicates finding an optimal time for any data reporting
requirement. In general, however, wildfires tend to occur in the summer
and fall as temperatures are high, vegetation dries out from lack of
rain, and lightning is more prevalent. Time periods allowed for
prescribed burning usually occur outside of the wildfire season,
depending on the area. These facts suggest that, while the summer is a
busy time because of wildfires, the spring and fall can be a busy time
for prescribed burning and that the added workload for any prescribed
burn data reporting might, therefore, benefit from a flexible time
window during which to report data.
    This workload consideration would also need to be balanced with
when States could practically complete data collection, QA, and data
submission, including any coordination necessary between State air
quality and forestry departments. Not only must State coordination
internally be considered, but also any coordination needed with the
representatives of military bases who are responsible for prescribed
burning on those Federal lands. A final relevant factor for a proposed
due date is when the EPA would need the data to meet timing objectives
for the NEI, allowing enough time for review by data partners at State
air quality and forestry departments.
    To determine the first year for any requirements to report
prescribed fire data, the EPA is considering the extent to which
agencies are providing detailed data voluntarily. It is expected that
any agency not currently providing voluntary input may not have a
program

to collect prescribed burning data after the burn has occurred. In the
2017 and 2020 NEIs, 19 agencies voluntarily participated in providing
input to the prescribed burning activity data, which is one of the best
participation rates of any triennial NEI years. To aid in deciding on a
proposed action and to assess burden, we assumed that 63 State, local,
or tribal agencies would need to develop some aspect of a prescribed
burning data collection program. We recognize that there are some areas
in which prescribed burning does not occur. It is expected that most
air agencies (States, locals, or tribes) encompassing areas in which
prescribed burning activity occurs may have a permitting program in
place from which they could build a data collection program. The EPA
urges commenters to provide any additional information about how many
State, local, or tribal agencies may be required to report prescribed
fire data if the EPA were to finalize the proposed requirements of this
action.
    EPA is considering the locations from which fires should be
reported and the size of fires to be included. Regarding the locations
of fires, the EPA is already able to obtain data needed for some
Federal lands from national databases,\73\ but military prescribed
burning is not usually included. Based on analysis of available data
sources, prescribed burns on private lands within States and on
military lands appear to be the bulk of the data not currently
available.
---------------------------------------------------------------------------

    \73\ Hazard Mapping System (National Oceanic and Atmospheric
Administration); Incident Command System Form 209: Incident Status
Summary; Forest Service Activity Tracking System (U.S. Forest
Service); U.S. Fish and Wildland Service fire database.
---------------------------------------------------------------------------

    The EPA has analyzed voluntarily reported data from States for the
2017 NEI to consider an acreage reporting threshold above which data
would be required to be reported. The higher the acreage reporting
threshold, the fewer burns would need to be reported and the lesser the
burden on States. In that data, almost 90 percent of the acres from
prescribed burns were from events of 50 acres or more, and 95 percent
of the acres burned were from burns of 25 acres or more. This finding
suggests that setting the reporting threshold at either 50 or 25 acres
should capture the bulk of prescribed burning events occurring on
State, military and private lands that would be required under this
proposal. These data generally do not include prescribed burns on
military lands, and thus no information about those is currently
available to the EPA for analysis.
    The burden consideration should be balanced with the need to
characterize satellite-detected burns as being prescribed burns, since
otherwise they could be characterized as wildfires and assigned higher
emission rates in creating the NEI. Without other information, the NEI
approach assigns fires as prescribed burns or wildfires based on the
satellite data, the State, and the month; a chart of these assumptions
is available in Figure 2 (based on Figure 7-3 of the 2020 NEI TSD).
Additional information from States would improve this approach.
[GRAPHIC] [TIFF OMITTED] TP09AU23.034

BILLING CODE 6560-50-C
    The satellite data can also cause uncertainty in the acres burned
per fire, without ground-based observation data. The pixel size of the
satellite images determines the default size of these burns, which is
from 12 to 62 acres per pixel, depending on where in the U.S. the fire
occurs. Emissions from burns smaller than the assumed acres based on
pixel size would be overestimated, and emissions from burns larger than
the assumed size would be underestimated.
    Additionally, the EPA is aware of various types of prescribe burns:
broadcast burns, understory burning/underburning, and pile burns. These

burn types are defined by the Bureau of Land Management (BLM) on their
Prescribed Fire Terminology website.\74\ Broadcast burns are defined as
``a prescribed fire ignited in areas with little or no forest canopy
present.'' Understory burning is defined as ``A prescribed fire ignited
under the forest canopy that focuses on the consumption of surface
fuels but not the overstory vegetation,'' and pile burns are defined as
``a prescribed fire used to ignite hand or machine piles of cut
vegetation resulting from vegetation or fuel management activities.''
These burns can have different emission rates and other
characteristics, so the EPA would ideally have data from all these fire
types and would know the type of each fire reported. Additionally,
evidence suggests that in general, broadcast and understory burns
impact larger acres per event, because collecting material for pile
burns tends to happen over smaller, more manageable areas. Broadcast
and understory burning can include cuttings from fuels reduction
treatments and logging slash.
---------------------------------------------------------------------------

    \74\ Bureau of Land Management, ``Prescribed Burn Terminology,''
https://www.blm.gov/or/resources/fire/prescribedburns/burn_terminology.php.
---------------------------------------------------------------------------

    Different information is needed about prescribed burns depending on
the type of burning. The EPA recognizes that certain data fields needed
for pile burns are not available in the current reporting formats.
After consideration, the EPA proposes that for broadcast burns and
understory burns, the minimum data fields needed are: (1) a unique
identifier for the State, (2) the date of the burn, (3) State and
county code or tribal code, (4) the centroid of the latitude/longitude
coordinates of the burn for that date, (5) SCC (which provides the type
of burn), and (6) either the acres burned or the total planned acres
and percent burned. Additional data fields would be available for
optional reporting, including fuel type, fuel loading per acre, fuel
moisture (any or all of 1-hr, 10-hr, 100-hr, and 1000-hr values),
emission reduction technique, and burn perimeter geographic information
system (GIS) shape data. Emission reduction techniques are smoke
management practices that are used by fire managers to reduce air
quality impacts from prescribed fire and include burning fewer acres,
burning when large woody fuels have a higher fuel moisture content,
removing fuels before ignition among other techniques.\75\
---------------------------------------------------------------------------

    \75\ National Wildfire Coordinating Group, ``NWCG Smoke
Management Guide for Prescribed Fire,'' November 2020, PMS 420-3/
NFES 001279, Chapter 4, Section 2, pp. 146-164.
---------------------------------------------------------------------------

    For pile burns for each event, the EPA is considering that the
minimum data fields are essentially the same as for broadcast or
understory burns, but rather than acres burned (or total planned acres
and percent burned) a State would be required to report the number of
hand piles per acre and the number of machine piles per acres. In
addition, optional data fields for pile burns would include average
height and diameter of the piles.
    Given these considerations, this action proposes to require that
States report data for prescribed burns for certain burns within State
boundaries, including burns conducted on state-owned/managed, private,
and military lands. This proposed requirement would exclude reporting
of burns for which such data are already documented by certain agencies
or Federal Land Managers via freely provided Federal databases. This
proposed requirement considers that the EPA already has access to
prescribed burning data provided by USFS and the Department of the
Interior and thus avoids duplication of effort by States by excluding
such data from the proposed requirements (however, States are free to
report data from Federal lands if they choose to do so). This proposal
includes new data formats for reporting prescribing burning activity
data.
    The EPA additionally proposes that agricultural and land clearance
burns be excluded from the prescribed burns required to be reported. To
facilitate this exclusion, the EPA proposes to use the definition of
prescribed burns defined by 40 CFR 51.301 and proposes a definition of
agricultural burns to mean ``the use of a prescribed fire to burn crop
residue.''
    EPA is additionally proposing a requirement that State reports on
prescribed burns would be due within 6 months of the end of the
inventory year (i.e., the calendar year in which the emissions
occurred) starting with the 2026 inventory year; thus, if finalized,
prescribed burning data would be due by July 1, 2027, and then every
July 1 thereafter. This deadline and others are summarized below in
section IV.S. The EPA also proposes a requirement for States to report
data for broadcast and understory burns when such burns impact 50 acres
or more and to report data for pile burns when biomass is collected
from 25 acres or more. Further, the EPA proposes to require States to
report for burns with aspects of both broadcast/understory and pile
burning that are 25 acres or more and to report each aspect of a burn
separately. For all burns, the EPA proposes to require the minimum data
elements previously listed. States would still be able to voluntarily
report data about fires smaller than those proposed to be required
above.
    The EPA also is considering the size of the prescribed burns and
believes that it would be possible to calculate the acreage of a
prescribed burn in such a way as to avoid additional reporting
requirements. Therefore, the EPA is proposing a requirement that, in
determining whether a burn must be reported, States would add acres of
adjoining parcels of land together when those parcels would be burned
on the same day (e.g., if two pile burns were conducted on adjoining
parcels in increments of 15 acres on the same day, those burns would be
considered as 30 acres and would, under these proposed requirements, be
reported together because they would exceed the proposed 25-acre
reporting threshold for pile burns). Finally, irrespective of any
acreage threshold for mandatory reporting, the EPA intends to retain
voluntary reporting for fires of any size or type for both wildfire and
prescribed burning, which includes allowing States to report prescribed
burns that occurred on Federal lands when they are included in State
databases.
    One approach to ensure that the EPA has all needed data for
prescribed burning would be an effort to consolidate existing data
collection from other Federal agencies with State data collection;
however, this approach would require additional time, coordination, and
agreement with other Federal agencies. Proposing an approach that
requires such coordination would likely delay implementation;
therefore, in this proposed action, the EPA relies on other Federal
agencies continuing to provide such data voluntarily. This proposed
approach would allow the EPA to obtain the information currently
unavailable (i.e., prescribed burns on state-owned/managed land,
private land, and military land) without delaying its collection as
would occur if a coordinated state-Federal approach needed to be
devised. A similar voluntary approach has been used for point sources,
in which the Bureau of Ocean Energy Management voluntarily provides
point source emissions data for offshore oil platforms.
    The EPA is also considering several alternatives in addition to the
preferred alternative requirements described above. In the preferred
alternative, the EPA is proposing the 2026 inventory year as the first
inventory year to allow States more time to develop a prescribed
burning data collection program. These data would be required by July
1, 2027,

and every year thereafter. The EPA requests comment on Alternative M1,
which would include all aspects of the preferred alternative but would
start the reporting for the 2025 inventory year and data would be due
by July 1, 2026, and every year thereafter. The EPA requests comment on
Alternative M1 because we recognize the importance of creating this new
data flow about prescribed fires as soon as possible. In support of
Alternative M1 are several considerations: (1) many States already
permit prescribed fires and, therefore, the data collection may be more
easily developed building from a permitting program, (2) the regulatory
approach for prescribed burning is not on industrial facilities, and
thus States may have more flexibility in implementation, and (3) States
may want to push forward quickly with collection of this information to
better reflect the fire emissions in their State. The EPA urges
commenters to provide any additional information for the EPA to
consider that would address the challenges and benefits of an earlier
start to a prescribed fires requirement.
    The EPA is also soliciting comment on Alternative M2, which would
provide States more time to implement a prescribed burning reporting
requirement. Alternative M2 would include all aspects of the proposed
approach but would delay the reporting to start for the 2027 inventory
year, with the first collection on July 1, 2028. The primary reason to
consider this option is that it provides more time for States to
implement the necessary collection. The disadvantage of this approach
is that the data are not available sooner when compared to the
preferred alternative.
    Finally, the EPA is soliciting comment on Alternative M3, which
would be significantly different from the proposed requirements above.
Rather than collect data on a per-burn basis, Alternative M3 would
require States to report the counties, dates, and/or months in which
prescribed burns occurred. With Alternative M3, the EPA would use the
satellite detection information along with the additional information
from States such as comprehensive ground-based wildfire activity to
improve EPA's assumptions about which fires are prescribed burns. Fires
identified by satellite would be mapped to the counties, dates, and/or
months provided by States to better determine whether a fire is a
prescribed burn or a wildfire and to allow the EPA to use the most
appropriate emissions factors to estimate emissions. The primary
advantage of Alternative M3 over the preferred alternative is that it
lowers the burden on States and could presumably be implemented more
quickly. If the EPA were to select Alternative M3 (either alone or in
combination with one of the other alternative above), the EPA could
implement such a requirement as early as the 2024 inventory year, with
the same July 1 deadline as described above for the preferred
alternative. The disadvantage of Alternative M3 is that it does not
include information about the actual size or type of each burn, which
would allow for improved emissions estimates. For example, the number
of acres burned would continue to be estimated based on the pixel size,
which as previously described can overestimate or underestimate the
area burned and the emissions.

N. Revisions to Requirements for Agricultural Fires and Optional
Reporting for Wildfires

    Agricultural burning is an important source of emissions at the
regional scale and poses a unique challenge on the days in which burns
occur. The current AERR collects data on emissions of agricultural
burning from States as a nonpoint source (i.e., annual total emissions
by county and SCC). However, the day-specific nature of agricultural
burning can be critical because it can impact local air quality on
specific days and could contribute to regional haze or other episodic
pollutant problems in urban and rural environments. As a result of this
difference between the data collected from States and the timescale on
which the emissions occur, the EPA has concluded that the current AERR
requirements are insufficient to fully understand the impact of those
emissions. In considering improvements to the AERR, the EPA has
explored how to best gather information on agricultural burning
emissions.
    The EPA has developed a method to devise day-specific agricultural
burning emissions. This approach does not rely on state-submitted data
but can benefit from State input. The EPA is considering that the
availability of this method to calculate day-specific fires could
provide useful data without burdening States.
    The idea of day-specific agricultural burning was received as part
of comments during the public review of the 2013 AERR proposed
rule.\76\ The EPA's response to those comments stated, ``[t]he the EPA
disagrees with this comment because the lower emissions associated with
agricultural fires do not necessitate having the fires as daily
events.'' \77\ However, since the AERR was finalized in 2015, the EPA
continued to explore the possible impacts of agricultural burning
events and has determined that such events could, under the right
conditions, have a significant enough impact on downwind air quality
that a day-specific approach could be warranted.
---------------------------------------------------------------------------

    \76\ Comments submitted by Washington Department of Ecology, see
docket entry EPA-HQ-OAR-2004-0489-0066.
    \77\ See ``AERR Response to Comment document'' see docket entry
EPA-HQ-OAR-2004-0489-0077.
---------------------------------------------------------------------------

    Under the current AERR and for the 2017 NEI, six States and four
tribes submitted nonpoint, annual total emissions of agricultural
fires. To use these emissions for air quality modeling, the EPA uses
its own day-specific estimates to apportion the state-submitted
nonpoint data to days. This process can lead to errors when compared
with using day-specific ``event'' data, as is done for wildfires and
prescribed burning. The remaining State, local, and tribal agencies
either notified the EPA that they excepted EPA agricultural fire
emissions, or they were silent on this topic. This information suggests
that most States support EPA's agricultural fires method and would not
be impacted by any changes made to reporting requirements.
    Based on these considerations, the EPA proposes to add a new
subparagraph Sec.  51.15(h) in the proposed regulatory text that would
specify that when States report agricultural burning emissions, the
data would need to be reported in the same event-based data format as
is used for prescribed burning. Furthermore, this action allows for the
EPA to continue to provide the agricultural fires as day-specific data
for States to review, comment, or revise event-based submissions. This
proposed revision would take effect starting with the 2023 inventory
year.
    The current AERR allows for voluntary reporting by States of
wildfire emissions. Rather than reporting emissions, most States have
reviewed and commented on EPA's activity data compiled from national
databases in conjunction with satellite data. To formalize that
approach, the EPA proposes that States could voluntarily review and
comment on EPA-provided wildfire activity and emissions data. In
addition, the EPA proposes that a State may report wildfire timing and
activity data using the same event-based data format as is used for
prescribed burning.

O. Revisions for Onroad and Nonroad Emissions Reporting for California

    The EPA approves onroad mobile models for California for
transportation

conformity purposes and for use in SIPs. For the current AERR,
California is already required to report emissions from onroad mobile
sources rather than report MOVES inputs. While there is no EPA-approved
nonroad model, California has its own state-specific model. The current
AERR requirements, however, have limitations on two points that the EPA
has reconsidered in developing this proposed action.
    First, the current AERR does not specify what version of the
California onroad mobile model should be used when reporting to EPA,
nor what pollutants should be reported for onroad and nonroad mobile
sources. In reevaluating the existing requirements, the EPA is
proposing new language that would specify using an approved version of
the California onroad mobile model. This would ensure data quality and
that the latest methods are used, which would be consistent with EPA's
use of the latest version of MOVES for other States. In addition, the
EPA proposes that this subpart requires the same CAPs from California
as States.
    Second, the existing requirements cause a limitation in EPA's
understanding of how California has applied its model to estimate
emissions. Since there is no requirement to provide documentation,
there is no way for the EPA to provide transparency for NEI users about
the emissions data or QA measures that have been taken.
    Based on these considerations, the EPA proposes to add a new Sec.
51.15(e)(3) in the proposed regulatory text to specify that the EPA
would retain the existing approach of requiring California to report
CAP emissions from onroad and nonroad sources. The EPA additionally
proposes to include three new requirements to this subpart to address
the issues identified during EPA's review.
    First, to resolve the question of the latest version of the onroad
mobile model, the EPA proposes to add a new Sec.  51.5(m) in the
proposed regulatory text that would require California to use the
latest model version approved by the EPA as of January 1 of the
emissions inventory year and may optionally use a newer approved model.
For example, the onroad model approved as of January 1, 2023, should be
used to estimate and report emissions to meet the proposed requirements
in the new subparagraph Sec.  51.15(e)(3) of the proposed regulatory
text for the 2023 reporting year, or the State could optionally choose
to use a model approved by the EPA after that date.
    Second, to resolve the question of which pollutants should be
reported, the EPA proposes to add a new subparagraph Sec.
51.15(e)(3)(i) in the proposed regulatory text that would require
California to report emissions values for the same pollutants estimated
by the EPA model for criteria pollutants and precursors. Additionally,
this action proposes to add a new subparagraph Sec.  51.15(e)(3)(iii)
that would specify that California may voluntarily submit emissions of
HAP, greenhouse gases, or other pollutants, consistent with those
pollutants that are estimated by the MOVES model. If California does
not report these data, the EPA intends to use CAP/HAP ratios consistent
with the MOVES model and if California does report such emissions, the
EPA will evaluate the data and documentation to decide which approach
would be to the best advantage for the purposes of the NEI.
    Third, to resolve the lack of documentation about California's
onroad and nonroad mobile emissions, the EPA proposes to add a new
subparagraph Sec.  51.15(e)(3)(ii) in the proposed regulatory text that
would require California to submit documentation that describes the
model inputs, use of the model and any options selected, post-
processing steps, and the QA performed to estimate the emissions for
each county and SCC. This proposed requirement would allow commensurate
documentation, quality review, and transparency for California's onroad
and nonroad emissions as exists for mobile sources in the NEI for other
States. The EPA intends to evaluate the documentation provided by
California, particularly for HAP, and determine the best approach for
ensuring complete HAP data from mobile sources that uses sufficiently
robust and transparent approaches.

P. Clarifications for Reporting Emission Model Inputs for Onroad and
Nonroad Sources

    The current version of the AERR requires States, except for
California, to report MOVES model inputs for onroad and nonroad sources
or to accept EPA-provided emissions data. The EPA has reviewed the
current process and is aware that States may have access to better data
than the EPA can obtain on its own, for example, to vehicle
registration data and inspection and maintained program data maintained
by States that are not available in any national databases (except as
collected under this subpart). The EPA recognizes that the current AERR
is not specific about which parts of the MOVES model inputs are most
critical or whether there are some parts of those inputs that the EPA
would not use. Additional clarification about which MOVES inputs are
the most important could encourage States to submit at least that
minimum amount of data and could also help to avoid misunderstandings
regarding which data elements the EPA does not intend to use.
    In addition, the current AERR does not specify a mechanism by which
States may express their review and acceptance of EPA-provided MOVES
inputs and emissions. Like nonpoint sources as described above, such a
mechanism would be useful to allow the EPA to develop a formal record
of States' choices about submitting model inputs or accepting EPA
inputs and emissions.
    Furthermore, some States do not notify the EPA of their acceptance
of MOVES inputs or emissions. While the EPA might simply assume that no
notification means that States do accept it, such an approach does not
create a clear record for the EPA if disputes in emissions data arise
later. Resolving this limitation of the current process would avoid
possible conflicts in the future.
    While many States submit MOVES inputs, some States still do not.
Section 5.5 (Table 5-4) of the 2020 NEI TSD describes that 28 States,
including the District of Columbia, and 5 local agencies provided MOVES
inputs, out of 82 total States and local agencies reporting.
Furthermore, different agencies provided different degrees of input,
suggesting that an approach to clarify the most important data formally
with this action could be useful to agencies seeking to prioritize
their efforts. While there are many separate inputs listed in the 2020
NEI TSD, just a handful of these are most important to receive from
States.
    To ensure more data provision by States and avoid confusion, the
EPA proposes to list the minimal MOVES input requirements.
Specifically, the new Sec.  51.15(e)(1) included in the proposed
regulatory text would require that the minimum requirements for States
to provide are: (1) a county database checklist, (2) vehicle miles
travelled by county and road type, and (3) vehicle population by
county, vehicle type, fuel type, and age.
    Further, this action proposes to clarify with the new Sec.
51.15(e)(2) in the proposed regulatory text that if a State has
relevant data for the inventory year, States may optionally provide
inputs to the latest EPA-developed mobile emissions model for the
following data: (1) hourly average speed distribution by vehicle type,
ideally different for weekday and weekend (distance traveled in miles
divided by the time in hours), (2) vehicle age distribution, (3)
inspection and maintenance program

information, and (4) documentation that describes how model inputs were
created and the QA steps performed. The intent of listing out these
optional MOVES inputs is to explicitly exclude those MOVES inputs that
the EPA does not intend to use, which are fuel data and meteorological
data. Any fuel data that States would like the EPA to consider should
be incorporated into the default MOVES database. If available, States
may optionally send fuel data to the EPA at [email protected].
    As noted above, some States do not notify the EPA of their
acceptance of EPA-provided MOVES inputs and emissions. To address this
issue, the EPA is proposing a more formal approach in future inventory
years. If a State were to not respond using the standard approach
provided, the EPA could follow up with the State to notify them of the
compliance concerns and allow the State the opportunity to comply with
the AERR.
    To address this issue, the EPA proposes to add a new subparagraph
Sec.  51.15(e)(4) in the proposed regulatory text to clarify that
States other than California may, in lieu of submitting any data,
review and accept existing the EPA model inputs and emission estimates.
The EPA further proposes in the paragraph that States would be required
to use an electronic data collection approach provided by the EPA to
review, comment on, and accept EPA model inputs and emission estimates.
The approach that the EPA would implement to support that proposed
requirement would be in EIS like the Nonpoint Survey described in
section IV.J of this preamble or an approach to upload data files and
enter data on a shared folder such as Sharepoint. This goal with these
proposed provisions is to achieve the consistency needed for the Agency
to avoid the potential problems created under the current less specific
approach.

Q. Definition of Actual Emissions

    The term ``actual emissions'' is used in CAA sections 112, 172, and
182 among others, but no definition is provided of that term by the
Act. In CAA section 112(a), the term is used to define the terms
``modification,'' ``offsets,'' and ``early reduction.'' In CAA section
172(c)(3) and section 182(a)(1), the term is used to describe the
emissions that must be reported by States as part of SIPs. Because this
subpart implements aspects of the Act for emissions reporting to EPA, a
definition of this term that is appropriate for reporting of emissions
would be useful to ensure clarity about which emissions are required to
be reported. The EPA recognizes that the phrase ``actual emissions'' is
used in other contexts within 40 CFR part 51 that are distinct from the
emissions data reporting context. The proposed definition would only
apply to the provisions of the AERR; therefore, it would affect both
annual emissions data reporting as well as emissions included in SIP
inventories.
    The current AERR regulations in Subpart A of Part 51 have not
previously provided a definition of ``actual emissions'' for use in
implementing this subpart. A lack of a definition has caused confusion
because emissions generating activities can be divided into categories,
including emissions occurring during (1) steady State operating
conditions, (2) periods of process startup or shutdown, and (3) periods
of process malfunction. This confusion has prompted the need for the
EPA to clarify.
    To attempt to clarify what should be reported for SIP purposes, the
EPA has previously included a definition of ``actual emissions''
through the guidance document ``Emissions Inventory Guidance for
Implementation of Ozone and Particulate Matter National Ambient Air
Quality Standards (NAAQS) and Regional Haze Regulations.'' \78\ The
guidance definition States, ``actual emissions means the emissions of a
pollutant from an affected source determined by taking into account
actual emission rates associated with normal source operation and
actual or representative production rates (i.e., capacity utilization
and hours of operation) (40 CFR 51.491). This is in contrast with
potential emissions or allowable emissions. These actual emissions
should include emissions of a pollutant that occur during periods of
startup, shutdown, and malfunction.''
---------------------------------------------------------------------------

    \78\ Emissions Inventory Guidance for Implementation of Ozone
and Particulate Matter National Ambient Air Quality Standards
(NAAQS) and Regional Haze Regulations, U.S. EPA, EPA-454/B-17-002,
May 2017.
---------------------------------------------------------------------------

    The EPA is also considering the connection between the term actual
emissions and duration of the emissions for the NEI (annual) versus for
SIPs that can include other durations (e.g., ozone-season-weekday for
the ozone NAAQS or average season day for the 24-hour PM2.5
NAAQS). To support all EPA functions that use data collected by the
AERR, the term actual emissions in the context of the AERR must reflect
the types of activities relevant to include in an emission value rather
than whether that emissions value is annual or some other temporal
resolution like average day. Thus, an ideal definition for the AERR
would allow for the annual NEI reporting to refer to ``annual actual
emissions'' while an ozone SIP requirement ozone-summer-weekday
emissions could also be ``actual emissions'' associated with summer
weekdays.
    Based on these considerations, the EPA proposes to add a definition
of ``actual emissions'' within Sec.  51.50 of this subpart. The
proposes definition states, ``Actual emissions'' means, for the
purposes of this subpart, the emissions of a pollutant from a source
that is required to be reported under this rule, determined by
accounting for actual emission rates associated with normal source
operation and actual or representative production rates (i.e., capacity
utilization and hours of operation). Actual emissions include emissions
of a pollutant that occur during periods of startup, shutdown, and may
include malfunctions. Since malfunctions are, by nature, unpredictable
and given the myriad different types of malfunctions that can occur,
malfunction emissions are difficult to estimate. However, to the extent
that malfunctions become a regular and predictable event, then such
emissions should be quantified with regular and predictable emissions
and included in actual emissions.''
    To the extent that malfunction emissions can be included in the
emissions reported under the AERR, the EPA is additionally considering
that emissions from malfunctions may need to have special treatment for
use in both the NEI and SIP contexts. For example, when the emissions
are used for air quality modeling for model performance evaluation, it
would be critical to have the time span during which malfunction-
related emissions occurred. If malfunction emissions were included as a
single value summed with other emissions, then the emissions would not
exhibit the hourly or daily peaks in emissions associated with the
malfunction. This would not only miss those peak impacts during the
times of the malfunction, but also could increase emissions across the
entire year to a level not useful for model performance evaluation.
Another example is that for projected inventories required for the
nonattainment area for the PM2.5 SIP or for ozone and
PM2.5 modeled attainment demonstrations, including
malfunctions from the base year in future year modeling may not result
in the best policy outcomes. This is because malfunctions, if they
occurred in the future year, would undoubtedly be different in both
timing and magnitude. Since malfunctions by definition are not

predictable, including them in future year modeling could be
problematic.
    The EPA is soliciting comment on a possible additional requirement
that may be included in any final action on this proposal. This
additional ``Malfunction Option'' requirement would be for States and
owners/operators to report their malfunction emissions as a separate
value from the other emissions. This would allow for consistency across
NEI, SIPs, and all States to ensure that both malfunction emissions are
included (based on the proposed definition), but also the malfunction
emissions do not adversely impact the use of the emissions data for
some purposes such as modeling and projected inventories. If the EPA
were to require the Malfunction Option in the final rule, States and
owners/operators would need to report the approximate date of
occurrence, the approximate number of days of the occurrence (if more
than one day), and the estimated emissions associated with each
malfunction. These additional fields would be reported as associated
with the affected units and processes (when applicable) and release
points. The EPA proposes that reporters would assign each emissions
value with an emissions operating type code that denotes the emissions
as being associated with a malfunction. In addition, the EPA intends to
adjust the available codes in the EIS (and CAERS) by retiring the
existing codes and creating codes for routine (steady-state and
startup/shutdown), malfunction, and startup/shutdown. Under this
proposed requirement, the routine value would always be required (and
as described above, would be expected to include startup/shutdown). The
malfunction value would be required in the event of a malfunction. The
startup/shutdown value would be an optional value that a State or
owner/operator could provide to give additional information about the
startup/shutdown portion of the routine emissions.
    EPA is additionally considering an alternative implementation of
the Malfunction Option. In this alternative implementation, rather than
requiring approximate date, approximate duration, and associated
emissions, owners/operators would only need to report the annual total
emissions and the emissions operating type code for all malfunctions
that occurred each year.

R. Provisions for State Implementation Plans

    To promote a consistent approach to emissions inventory data
collection from States, portions of 40 CFR part 51 that address SIP
requirements reference the current AERR when addressing SIP inventory
requirements. Within Part 51, Subparts G, P, X, Z, AA, and CC all
reference the AERR. The EPA has reviewed these references to the AERR
to ensure that the changes proposed to the AERR do not require changes
to those other subparts. The EPA determined that no such changes to
these other subparts were necessary. However, the EPA did identify
certain aspects of the current AERR and proposed AERR revisions that
could cause confusion for SIP inventory requirements. As a result, the
EPA is proposing additional revisions within the AERR to prevent such
confusion, and these changes relate to three considerations: (1) the
definition of point sources, (2) the level of detail required for
emission inventories, and (3) the timing of the triennial NEI. Each of
these considerations is handled separately in the paragraphs below.
1. Point Source Thresholds
    Subpart G refers to the AERR point source definition directly or
indirectly at Sec.  51.122(g); Subpart X at Sec.  51.915; Subpart Z at
Sec.  51.1008(a)(1), (a)(2) and (b)(1); Subpart AA at Sec.  51.1115(d)
and (e), and Subpart CC at Sec.  51.1315(d) and (e). Subpart G directs
States to submit a statewide NOx emissions inventory and, in doing so,
to use the AERR point source definition. The ozone implementation rules
(Subparts X, AA, and CC) require States to report point sources for the
base year inventory for the nonattainment area using the AERR point
source definition. Finally, the PM implementation rule of Subpart Z
directs States to use the AERR point source definition to determine
point sources, which applies for both the base year inventory and for
the attainment projected inventory for the nonattainment area.
    In referencing the AERR, the SIP inventory requirements do not
mention specific pollutants for which the AERR point source definition
(which uses reporting thresholds for all CAPs) should be used. For
example, the ozone implementation rules' inventory requirements rely on
CAA section 172(c)(3), which requires emissions of ``the relevant
pollutant or pollutants'' when preparing nonattainment SIP inventories
for ozone. In the case of ozone, these relevant pollutants are
NOX and VOC, but the references from the ozone SIP
requirement rules to the AERR are not specific to these pollutants.
Thus, under the current approach, one could incorrectly assume that all
AERR point sources defined with all CAP PTE reporting thresholds would
need to be treated as point sources for an ozone SIP, irrespective of
the level of NOX and VOC at those sources. This proposal
clarifies that only those sources with NOX or VOC emissions
exceeding the AERR point source PTE reporting thresholds would be
required to be reported as point sources in an ozone SIP. Similarly,
this proposal would include similar clarifications for PM2.5
and its precursors when preparing nonattainment SIP inventories for
PM2.5. In addition, the EPA intends for the addition to the
point source definition included in this proposal based on HAP should
not impact the point source definition for SIPs.
    To ensure no change to the other subparts that refer to the AERR's
point source requirements, the EPA proposes to revise Sec.  51.10 of
this subpart by adding paragraph (b) to list Part 51 Subparts G, X, Z,
AA, and CC and specify the parts of the point source definition that
are applicable to each. Specifically, for Subpart G, the EPA proposes
that only the NOX reporting threshold of the proposed Table
1A to Appendix A of this subpart would be relevant. For ozone
implementation under Subparts X, AA, and CC, the EPA proposes that the
NOX and VOC reporting thresholds of the proposed Table 1A to
Appendix A of this subpart would be relevant. For PM implementation
under Subpart Z, the EPA proposes that the NOX, VOC,
SO2, NH3, PM2.5, and PM10
reporting thresholds of the proposed Table 1A to Appendix A of this
subpart would be relevant.
2. Detail Required by Emission Inventory Provisions of SIP
Implementation Rules
    In addition to the point source definition referenced throughout
Part 51, the SIP requirements within Part 51 refer to the AERR by
requiring that the detail of the emissions inventory under those
subparts ``shall be consistent with the data elements required by 40
CFR part 51, subpart A'' (see 40 CFR 51.122(g), Sec.  51.915, Sec.
51.1008 (a)(1)(vi), Sec.  51.1115(e), and Sec.  51.1315(e)). Several
revisions are being proposed by this action that would impact the
``detail of the emissions inventory,'' so additional information has
been included in this proposed action to clarify which changes do not
apply to the SIP inventory requirements.
    The proposed revisions to this subpart for State requirements
regarding the ``detail of the emissions inventory'' have been described
above and are summarized here to provide clarity about which changes
would need to be considered when interpreting the Part

51 references to the AERR. Table 4 below lists the proposed changes to
relevant requirements of action in the left column and how the EPA
proposes that they would or would not impact the ``detail of the
emission inventory'' requirement included in the SIP inventory
requirements.

   Table 4--Impacts of Proposed State Reporting Requirements on 40 CFR
                      Subparts G, X, Z, AA, and CC
------------------------------------------------------------------------
                                                   Impact of proposed
                     Proposed new or revised     requirement on 40 CFR
                         State  reporting      subparts G, X, Z, AA, and
                     requirement for the AERR         CC? (Yes/No)
------------------------------------------------------------------------
1.................  Requirement to report      No: Does not change
                     intermittent electricity   emissions required to be
                     generation fuel use        reported under these
                     (section IV.D of this      subparts. Emissions (but
                     preamble).                 not daily activity data)
                                                from intermittent
                                                electricity generation
                                                sources would continue
                                                to be required to be
                                                included in SIP
                                                inventories. The
                                                proposed AERR revisions
                                                improve States' ability
                                                to gather the data they
                                                need to estimate and
                                                consider these emissions
                                                in SIPs.
2.................  Requirements to use        Yes: Point source
                     source test data when      emissions would need to
                     available, indicate why    be estimated as proposed
                     it is not used, and        in new Sec.   51.5(a)
                     otherwise use best         through (d) of the
                     available emissions        proposed regulatory
                     estimation method          text.
                     (sections IV.I.6 and
                     IV.I.7 of this preamble).
3.................  Additional required point  Yes: Point source
                     source data fields         inventories developed
                     (sections IV.E, IV.I.3,    and submitted under
                     IV.I.4, IV.I.5, IV.I.8,    these subparts would
                     IV.I.10, IV.I.11,          need to include
                     IV.I.12, and IV.I.16 of    additional data fields.
                     this preamble).            See new Sec.
                                                51.15(j)(1) and Sec.
                                                51.40(b) of the proposed
                                                regulatory text.
4.................  More specific airport and  No: Airport and rail yard
                     rail yard requirements     emissions are still
                     and implementation         required as point
                     options (sections IV.I.1   sources if those
                     and IV.I.2 of this         facilities exceed the
                     preamble).                 point source reporting
                                                thresholds in Table 1A
                                                to Appendix A of this
                                                subpart. See new Sec.
                                                51.15(j)(1) of the
                                                proposed regulatory
                                                text.
5.................  Requirement to complete    No: Only relevant for NEI
                     an online nonpoint         process and not for
                     survey (section IV.J of    SIPs. See New Sec.
                     this preamble).            51.15 and Sec.
                                                51.15(j)(2) of the
                                                proposed regulatory
                                                text.
6.................  Requirement to report      No: Nonpoint emissions
                     nonpoint activity data     are still required. See
                     and optionally report      new Sec.   51.15 and
                     emissions data for some    Sec.   51.15(j)(2) of
                     emissions sectors,         the proposed regulatory
                     including an option to     text.
                     review and accept EPA-
                     provided data to comply
                     (section IV.J of this
                     preamble).
7.................  Requirement for            No: Nonpoint emissions
                     documentation when         are still required and
                     nonpoint emissions are     no additional
                     reported (section IV.J     documentation
                     of this preamble).         requirement. See new
                                                Sec.   51.15 and Sec.
                                                51.15(j)(2) of the
                                                proposed regulatory
                                                text.
8.................  Requirement for            No: Onroad and nonroad
                     documentation when         emissions are still
                     onroad and nonroad         required and no
                     emissions are reported     additional documentation
                     by California or by        requirement. See new
                     other States when they     Sec.   51.15 and Sec.
                     optionally provide         51.15(j)(3) of the
                     emissions in addition to   proposed regulatory
                     MOVES inputs (section      text.
                     IV.O of this preamble).
9.................  Specific approach for      Yes (for States
                     reporting nonpoint         overlapping tribes that
                     activity data and          have emissions inventory
                     emissions when Indian      reporting obligations):
                     country boundaries         Clarifies how States and
                     overlap with county        tribes should report
                     boundaries (section IV.L   nonpoint, onroad, and
                     of this preamble).         nonroad emissions when
                                                both the State and the
                                                tribe have
                                                implementation planning
                                                authority within a
                                                nonattainment area. See
                                                new Sec.   51.15 and
                                                Sec.   51.15(j)
                                                paragraphs (2)(iv) and
                                                (3)(ii) of the proposed
                                                regulatory text.
10................  Requirement to report      No: Prescribed fire
                     prescribed burning         emissions are still
                     activity data (section     required. See new Sec.
                     IV.M of this preamble).    51.15 and Sec.
                                                51.15(j)(2)(ii) of the
                                                proposed regulatory
                                                text.
11................  Change to make             No: Agricultural burning
                     agricultural burning       emissions are still
                     optional and submitted     required as a nonpoint
                     as an event source         source. See new Sec.
                     (section IV.N of this      51.15 and Sec.
                     preamble).                 51.15(j)(2)(ii) of the
                                                proposed regulatory
                                                text.
------------------------------------------------------------------------

    As shown in the table above, only three of the proposed changes for
State annual or triennial reporting under this action impact the
requirements of Part 51 Subparts G, X, Z, AA, and CC. The three that do
impact the requirements help with resolving ongoing nonattainment
emissions data challenges, so it is appropriate for these subparts to
continue to refer to the AERR as revised.
    For the proposed requirement 1 in Table 4, more completely
described in section IV.D of this preamble, the proposed change to the
AERR has a positive impact on emissions data that would be available to
the State after implementing the provisions of this action. This
proposed action facilitates activity data collection from small
generating units as an annual requirement, which would allow States
with small generating units operating to offset or meet peak
electricity demand to have the data that they need to better reflect
emissions from such sources in their planning inventories for SIPs.
    The proposed set of requirements listed as item 2 in Table 5
specifies data quality requirements for calculating and reporting
emissions for point sources. These are described more completely in
sections IV.I.6 and IV.I.7 of this preamble. If these proposed
requirements were finalized, point sources reporting CAP emissions to
States for both annual emissions reporting to the EPA and SIP purposes
would need to meet new data quality requirements.
    The proposed requirement 3 in Table 4 is a collection of specific
new data fields that are more completely described in section IV.I of
this preamble and the proposed Table 2A to Appendix A of this subpart.
Any new data elements finalized from this proposed action would be
collected by States to meet requirements of the AERR and, therefore,
would be available for States to submit as part of their planning
inventories for SIPs. Thus, while the SIP inventory requirements are
indirectly modified by this proposed action, this

action does not impose additional burden for nonattainment area
inventories because this subpart uses the same requirements for both
annual reporting of point sources and for States' planning inventories
for SIPs.
    Finally, the proposed requirement 9 of proposed Table 4 is fully
described in section IV.L of this preamble addresses an existing
challenge for both the NEI and SIP planning inventories. As previously
described, a clear approach for States and tribes to share reporting of
county total emissions data has not been available. When both a State
and an Indian Tribe share implementation planning authority for a
nonattainment area, this action proposes a new requirement for how
States and tribes (or the EPA on their behalf) should develop and
report nonpoint, onroad, and nonroad emissions. As proposed in new
paragraph Sec.  51.15(j), subparagraphs (2)(iv) and (3)(ii) of the
proposed regulatory text, the approach would apply the same technique
described for nonpoint activity and emissions for triennial reporting
to the emissions reporting for the nonattainment area needed for SIPs.
To be clear, this situation would arise if the nonattainment area
included some lands that fell within the geographic scope of the
State's implementation planning authority as well as some lands within
the geographic scope of the tribe's implementation planning authority
in accordance with TAS for that tribe.
    In evaluating the connection between the elements required to be
reported under the AERR and the elements required to be provided in SIP
submissions pursuant to other Part 51 subparts that generally reference
the AERR, the EPA noticed several differences. The current AERR
includes some requirements that were intended to apply only to the
triennial NEI emissions data collection and not to impact requirements
for SIPs. The primary discrepancy is that as per CAA Section 172(c)(3),
SIPs ``shall include a comprehensive . . . inventory of actual
emissions from all sources of the relevant pollutant or pollutants.''
The ``comprehensive'' and ``all sources'' part of this requirement are
not technically satisfied for certain provisions of the AERR. For
example, the AERR allows for reporting model inputs (rather than
``emissions'') for mobile sources. Similarly, the AERR makes optional
certain important emissions sources such as windblown dust, biogenic
emissions from soils and vegetation, prescribed fires, and wildfires,
but these sources must generally be included in inventories pursuant to
172(c)(3). The EPA provides guidance documents and training for SIP
inventory preparation that help ensure that these differences do not
result in inadequate SIP inventories. This action proposes to provide
additional clarity on these issues regarding what States need to
report.
    Part of this additional clarity has previously been described in
section IV.R.1 of this preamble regarding which pollutants should be
included in SIP planning inventories associated with the Part 51
subparts that reference the AERR. In addition, this proposed action
includes a new paragraph Sec.  51.15(j) in the proposed regulatory text
that lists out inventory requirements for SIPs required under Part 51
Subparts G, X, Z, AA, and CC that are different from requirements for
annual or triennial reporting for the NEI. First, this proposed action,
when referring to SIP planning inventories, would define point sources
only by the relevant CAP point source reporting thresholds under a new
paragraph Sec.  51.10(b) in the proposed regulatory text and not by the
other criteria such as the new criteria for HAP for major and non-major
sources. This proposed revision would retain the existing definition of
point sources in this subpart for references from other Part 51
subparts to the AERR. Second, this proposed action would clarify that
for SIP planning inventories, airports and railyards would need to be
reported as point sources only when they meet the point source
reporting threshold and otherwise could be included as a nonpoint
(county-total) source. This contrasts with the triennial requirement
for which the EPA provides data for review and comment by States for
all airports and railyard data, including ones much smaller than the
point source reporting thresholds. Third, this proposed action would
further clarify in new paragraph Sec.  51.15(j)(2)(iii) that SIP
planning inventories should include emissions from all sources,
irrespective of any other approaches required or made optionally
available by the AERR for the triennial submission of nonpoint, onroad,
and nonroad sources.
3. Emission Inventory Years
    The third and final type of reference to the AERR from other
subparts within Part 51 is about the year of the triennial NEI. Such
references appear in Subpart P at Sec.  51.308(f)(2)(iii) and Sec.
51.308(g)(4); Subpart X at Sec.  51.910(d); Subpart AA at Sec.
51.1110(b), and Subpart CC at Sec.  51.1310(b).
    Subpart P provides requirements for State implementation of the
regional haze program, and Sec.  51.308(f)(2) provides the requirements
for the long-term strategy to be included in periodic revisions of
regional haze SIPs. For emissions inventories, paragraph (f)(20)(ii)
states that ``[t]he emissions information must include, but need not be
limited to, information on emissions in a year at least as recent as
the most recent year for which the State has submitted emission
inventory information to the Administrator in compliance with the
triennial reporting requirements of Subpart A of this part.''
Additionally, paragraph (g)(4) of the same section provides
requirements for periodic reports describing progress towards the
reasonable progress goals; and this paragraph has a similar reference
to the year of triennial submissions to indicate the period over which
the State must perform an analysis tracking the change in emissions. No
provision of this proposed action would impact the inventory year
required for regional haze SIPs, because this action proposes to retain
triennial inventory requirements. Thus, under this action, the subpart
P requirement that references triennial reporting is still relevant
since emissions inventories would continue under this proposed action
to be collected on triennial inventory years.
    Within Part 51 Subpart X, Sec.  51.910(d) addresses what year
should be used for the baseline emissions inventory for Reasonable
Further Progress (RFP) plans. This paragraph requires that the
appropriate year is at least as recent as the most recent year for
which a complete inventory is required to be submitted to the EPA under
the provisions of the AERR. The phrase ``complete inventory'' means the
triennial inventory, which are the only inventories for which all
source categories could be reported by a State under the AERR. No
provision of this proposed action would impact the inventory year
required for SIPs under Subpart X, because this action proposes to
retain triennial inventory requirements.
    Part 51 Subpart AA includes the same statement to specify the
baseline emission inventory year needed to meet requirements for RFP,
which appears at Sec.  51.1110(b). In addition, Sec.  51.1115(a) refers
to the year used for the baseline emission inventory for RFP to explain
which years can be used for the base year inventory for the
nonattainment area. Likewise, Part 51 Subpart CC includes the same
reference to the triennial inventory year at Sec.  51.1310(b). In all
cases, no provision of this proposed action would impact the inventory
year required for SIPs under Subparts X, AA, or CC because this

action proposes to retain triennial inventory requirements.

S. Summary of Expected Timing for Proposed Revisions

    Unless otherwise noted, the proposed revisions in this action would
apply for the first inventory reporting year after promulgation of the
final rule. At the time of this proposal, the EPA expects that the
final rule will be in place for the 2023 triennial reporting year,
though some provisions would not take effect until later years. These
proposed deadlines depend on an assumed final rule promulgation date
prior to December 2024. If a final version of this subpart were delayed
beyond December 2024, the EPA may delay the phase-in of earlier
deadlines. Table 5 below summarizes the intent of this proposed action
with respect to deadlines.

   Table 5--Proposed First Possible Date for Deadlines Associated With
                Proposed Revisions to 40 CFR 51 Subpart A
------------------------------------------------------------------------
     First possible date                      Requirement
------------------------------------------------------------------------
                     Dates for States--point sources
------------------------------------------------------------------------
11/1/2025....................  Proposed first deadline to notify the EPA
                                if intend to use CAERS (for 2026
                                inventory year).
9/30/2024....................  Proposed first deadline for States/locals
                                to submit landing and takeoff data for
                                the 2023 inventory year (could be later
                                than this, since States have minimum of
                                60 dates to review).
1/15/2025....................  Proposed deadline for air agencies 2023
                                NEI point source reporting (for CAP and
                                voluntary HAP including airports and
                                rail yards).
1/15/2026....................  Proposed deadline for air agencies 2024
                                NEI point source reporting (for CAP and
                                voluntary HAP).
3/31/2026....................  Proposed first deadline for States to
                                submit their HAP reporting application
                                (for the 2026 inventory year).
1/15/2027....................  Proposed deadline for 2025 NEI point
                                source reporting (for CAP and voluntary
                                HAP).
1/15/2028....................  Proposed deadline for 2026 NEI point
                                source reporting, for CAP and mandatory
                                HAP when the State has an approved HAP
                                reporting application. Includes the
                                first year for mandatory reporting for
                                intermittent EGUs and required new data
                                fields including release point
                                coordinates, title V permit ID,
                                regulatory codes, and changes to
                                portable sources reporting.
9/30/2028....................  Proposed first deadline for earlier State
                                point source reporting (for 2027
                                inventory year). This is also the first
                                deadline for which the same point
                                sources must be reported each year (no
                                higher reporting thresholds for non-
                                triennial inventories).
5/31/2031....................  Proposed first deadline for even earlier
                                State point source reporting (for 2030
                                inventory year and later).
------------------------------------------------------------------------
              Dates for States--other sources besides point
------------------------------------------------------------------------
1/15/2025....................  Proposed deadline for 2023 NEI for rail
                                yards, mobile source inputs, California
                                mobile source emissions and
                                documentation, and nonpoint source
                                emissions and documentation for sources
                                without EPA tools.
3/31/2025....................  Proposed deadline for 2023 NEI nonpoint
                                survey.
7/1/2027.....................  Proposed first deadline for required
                                annual prescribed burning activity data.
Within 30 days, or longer as   Proposed timing for States to report
 provided by EPA.               nonpoint tool inputs during the year of
                                the inventory and the year after (e.g.,
                                during 2023 and 2024 for the 2023
                                triennial inventory year).
Within 60 days, or longer as   Proposed timing for States to report
 provided by EPA.               nonpoint emissions data for nonpoint
                                sources with EPA tools (e.g., during
                                2023 and 2024 for the 2023 triennial
                                inventory year).
------------------------------------------------------------------------
                       Dates for owners/operators
------------------------------------------------------------------------
10/31/2024...................  Proposed deadline for the ``One-time
                                Collection Option'' for HEDD-related
                                small generating units (if this option
                                were selected for the final rule).
5/31/2025....................  Proposed deadline for voluntary reporting
                                by owners/operators (for the 2024
                                inventory year).
5/31/2026....................  Proposed deadline for owners/operators
                                with point sources within Indian country
                                not reported by tribes to report CAP and
                                HAP (for the 2025 inventory year). Also,
                                the deadline for voluntary reporting by
                                other owners/operators.
5/31/2027....................  Proposed first deadline for all owners/
                                operators to report HAP for 2026
                                reporting year.
3/31/2028....................  First earlier proposed deadline for
                                owners/operators to report for the 2030
                                reporting year.
To meet Federal or State       Source test/performance test collection.
 testing requirement or
 otherwise within 60 days
 after completing testing.
------------------------------------------------------------------------

T. Summary of Regulatory Impact Analysis

    In this preamble section, we briefly summarize the costs and
benefits of this proposal. The RIA for this proposed rule provides
additional detail on these costs and benefits.\79\ The EPA encourages
commenters to provide any additional information not considered in the
RIA for this proposed rule or to provide comments on EPA's cost
estimation approaches.
---------------------------------------------------------------------------

    \79\ The RIA is available through the docket for this action.
---------------------------------------------------------------------------

    While methodological limitations prevented the EPA from monetizing
the potential human health and environmental benefits, given that no
changes in emissions or other environmental effects can currently be
estimated that may be directly attributed to the greater availability
and quality of emissions data, and in particular HAP emissions, we
present a qualitative discussion of benefits. These benefits include
those to communities that may be particularly impacted by pollutant
emissions, whether they be HAP or CAP.
    The benefits of the proposed revisions to the AERR of collecting
additional HAP, CAPs, controls, and sub-facility data include improved
understanding, awareness, and decision making related to the provision
and distribution of information. The information shared with EPA, and
incorporated into the NEI, could enable the public to make

more informed decisions on where to live and work, strengthen the
public's ability to adequately protect themselves from potential harm
from criteria air pollutants and air toxics, and provide a greater
capacity for meaningful involvement in the development and
implementation of local pollution management policies.
    This proposed action would ensure that communities have the data
needed to understand significant sources of air pollution that may be
impacting them and address existing environmental justice issues that
are discussed previously in this preamble. Additional benefits to these
communities include building public confidence through clear and
transparent emission measures and reports and the ability of the public
to better make facilities accountable for their emissions. Availability
of increased information on HAP emissions can also be used to advance
the Agency's environmental justice goals by increasing the
understanding of the potential impacts of air toxics emissions from
regulated facilities on minority and disadvantaged communities who have
been historically burdened by often difficult to detect and undisclosed
pollution that is experienced on a regular basis. The required
reporting of HAP emissions data will increase EPA's ability to
accurately conduct technology reviews pursuant to CAA section
112(d)(6), and risk reviews under CAA section 112(f)(2), which should
lead to future regulation of HAP that will be more effective in
reducing the burden of exposure of such emissions from what has
occurred in the past. These provisions are additionally informed by
Federal policy on environmental justice, including Executive Order
12898, which overlays environmental justice considerations for the EPA
to assess as part of such work. Even for owners/operators who also must
report emissions to the TRI program, this proposed action would
require_additional sub-facility details necessary for air quality
modeling that, in turn, would allow the EPA and other authorities to
assess local-scale community impacts and devise solutions for high-risk
areas.
    The proposed amendments would ensure HAP emissions data are
collected_consistently for all communities across the country.
Currently, the availability and detail of HAP emissions data varies
across States, which creates a situation where some communities have
incomplete or less accurate information than others, while still facing
the same or greater_potential risks. Transparent, public data on
emissions allows for accountability of polluters to the public
stakeholders, including communities, that bear the social cost of the
pollution.
    Finally, the proposed provision of additional information could
also lead to behavioral changes that could result in additional
benefits. In particular, voluntary initiatives by facilities to review
emissions control management practices and facility processes, set
goals for reductions in emissions, and institute ``good neighbor''
policies may result from provision of additional emissions data.
Potential changes in facility operations, such as reductions in
pollutant releases, could yield health and environmental benefits.
There may be instances where pollutant emissions are themselves
valuable product from a market standpoint (e.g., natural gas, that
includes HAP and methane, leaking from a pipeline), and their control
or capture may not only be beneficial to the environmental but also
beneficial to the firms that own the natural gas. While behavioral
changes from the provision of information may result from the rule and
are, in fact, one goal of these types of policies, they are not
mandated by the proposed action. The reporting of such emission data,
and its public disclosure, may provide social benefits in itself since
this data disclosure may incentivize emission reductions.
    Regarding the costs of this proposal, the proposed rule's cost to
State, local, Tribal government authorities is estimated at $28.5
million on average annually from 2024 to 2026, and then is estimated at
$27.7 million in 2027. For owners and operators of affected sources,
the proposed rule's cost is estimated at $89.0 million on average
annually from 2024 to 2026, and then is estimated at $450.1 million in
2027. Thus, the proposed rule's total cost impact is estimated at
$117.4 million on average annually from 2024 to 2026, and then is
estimated at $477.9 million in 2027. All of these costs are in 2021
dollars. The increase in costs for owners and operators of affected
sources in 2027 reflects full implementation of the proposed rule if
finalized for the entire population of affected sources.
    Regarding the population of affected sources for the 2024-2026 time
period, the EPA estimates the proposed rule would impact 85 State/
local/Tribal respondents and 820 owners/operators of facilities outside
of States' implementation planning authority. Owners/operators for an
estimated 40,315 facilities per year would also need to prepare for new
reporting requirements starting in 2027. Also, during this period, the
EPA estimates that owners/operators of 13,420 facilities would report
source test and performance evaluation data each year. Based on these
proposed requirements, States would continue to collect emissions data
from owners/operators of an estimated 13,420 facilities (based on State
regulations requiring owners/operators to do so). Starting in 2027, the
EPA estimates that, under the proposed AERR, owners/operators from
about 129,490 facilities would be required to report HAP as would about
235 owners/operators for reporting small generating unit data. More
information on the costs and estimates of affected facilities can be
found in the ICR supporting statement and the RIA for this proposal,
located in the docket for this action.
    In addition, as part of fulfilling analytical guidance with respect
to E.O. 12866, EPA presents estimates of the present value (PV) of the
social costs of the proposal over the period 2024 to 2033, an
analytical timeline that is approximately the first 10 years after this
rule is finalized as proposed. To calculate the present value of the
social costs of the proposed rule, annual costs are discounted to 2023
at 3 percent and 7 discount rates as directed by OMB's Circular A-4.
The EPA also presents the equivalent annualized value (EAV), which
represents a flow of constant annual values that, had they occurred in
each year from 2024 to 2033, would yield a sum equivalent to the PV.
The EAV represents the value of a typical cost or benefit for each year
of the analysis, consistent with the estimate of the PV, in contrast to
the year-specific estimates mentioned earlier in the RIA. The PV of the
compliance costs, in 2021 dollars and discounted to 2023, is $2.41
billion when using a 7 percent discount rate and $3.06 billion when
using a 3 percent discount rate. The EAV, an estimate of the annualized
value of the costs consistent with the present values, is $343 million
when using a 7 percent discount rate and $358 million when using a 3
percent discount rate. Table 6 summarizes the costs and benefits of
this proposal.

   Table 6--Summary of Benefits, Costs and Net Benefits for the Proposal From 2024 to 2033, Discounted to 2023
                                                [Million 2021$ a]
----------------------------------------------------------------------------------------------------------------
                                                                         Proposal impacts
                                                 ---------------------------------------------------------------
                                                             3 Percent                       7 Percent
                                                 ---------------------------------------------------------------
                                                        PV              EAV             PV              EAV
----------------------------------------------------------------------------------------------------------------
Total Monetized Benefits \a\....................                N/A
                                                                N/A
                                                 ---------------------------------------------------------------
Total Costs.....................................          $3,057            $358          $2,410            $343
                                                 ---------------------------------------------------------------
Net Benefits....................................                N/A
                                                                N/A
                                                 ---------------------------------------------------------------
Non-Monetized Benefits..........................  Improved emissions data access for State, local, and tribal
                                                  government agencies.
                                                  Increased emissions data for addressing local (environmental
                                                  justice) issues.
                                                  Better data to inform regulatory decision making
                                                  Increased emissions data to incentivize voluntary emission
                                                  reduction efforts by industry and others.
----------------------------------------------------------------------------------------------------------------
\a\ We have determined that quantification of benefits cannot be accomplished for this proposed rule. This is
  not to imply that there are no benefits of the proposal; rather, it is a reflection of the difficulties in
  monetizing the benefits for the listed categories with the data currently available. N/A = not available.

    These cost estimates include those for impacts to State, local, and
Tribal organizations that are engaging in voluntary activities that
would become codified as a result of this proposal if finalized. The
EPA has broken out those costs separately and provides discussion of
them in the RIA for this proposal. Similarly, we acknowledge that the
cost estimates for this proposal include those for revisions to SIP
planning activities, and we also break out these costs separately and
provide discussion of them in the RIA for this proposal.

V. Statutory and Executive Order Reviews

    Additional information about these statutes and Executive Orders
can be found at https://www.epa.gov/laws-regulations/laws-and-executive-orders.

A. Executive Order 12866: Regulatory Planning and Review and Executive
Order 13563: Improving Regulations and Regulatory Review

    This action is a ``significant regulatory action,'' as defined
under section 3(f)(1) of Executive Order 12866, as amended by Executive
Order 14094. Accordingly, EPA, submitted this action to the Office of
Management and Budget (OMB) for Executive Order 12866 review.
Documentation of any changes made in response to the Executive Order
12866 review is available in the docket. The EPA prepared an analysis
of the potential costs and benefits associated with this action. This
analysis, ``Regulatory Impact Analysis for the Proposed Revisions to
the Air Emissions Reporting Requirements,'' is also available in the
docket and is briefly summarized in section IV.T of this preamble.

B. Paperwork Reduction Act

    The information collection activities in this proposed rule have
been submitted for approval to the Office of Management and Budget
(OMB) under the Paperwork Reduction Act, 44 U.S.C. 3501 et seq. The
draft Information Collection Request (ICR) document prepared by the EPA
has been assigned the EPA ICR number 2170.09. You can find a copy of
the ICR in the docket for this rule, and it is briefly summarized here.
    In past years, the information collection under the existing AERR
has coordinated the various State emission inventory reporting
requirements and has streamlined the activities involved in submitting
certain emissions data to the EPA. The proposed revisions to the
collection would (1) continue this coordination to enable the EPA to
achieve uniformity and completeness in a national inventory to support
national, regional, and local air quality planning and attainment of
NAAQS and planning needed for meeting regional haze requirements, (2)
greatly improve HAP data collections that are voluntary under the
existing AERR, but are proposed herein to become mandatory (3) fill
other identified gaps in emissions inventories for sources within
Indian country, for certain small generation units, and for prescribed
fires nationally, and (4) greatly improve the availability of data
necessary for creating emissions factors.
    The draft ICR for this proposed action includes collection of both
mandatory and voluntary data from States (as defined in section III to
include certain local and tribal governments) for annual and more
extensive triennial collections of emissions data. The draft ICR also
covers the proposed collection of mandatory and voluntary data from
owners/operators that emit emissions at or above proposed reporting
thresholds and that perform source tests. While the focus of the draft
ICR is the 2024-2026 period, additional costs from 2027 and beyond are
included in Appendix A of the draft ICR to reflect additional costs
associated with full implementation of the proposed revisions.
    Respondents/affected entities: For the 2024-2026 period covered by
the draft ICR, the EPA estimates the proposed rule would impact 85
State/local/Tribal respondents and 813 owners/operators of facilities
outside States' implementation planning authority. Also, during this
period, the EPA estimates that owners/operators of 13,420 facilities
would report source test and performance evaluation data each year and
120,945 facilities (40,315 per year) would collect release point
latitude/longitude data for reporting in 2027. Based on these proposed
requirements, States would continue to collect emissions data from
owners/operators of an estimated 13,420 facilities (based on State
regulations requiring owners/operators to do so). Starting in 2027,
Appendix A of the draft ICR identifies owners/operators of an estimated
129,500 facilities from which this proposed rule would require HAP
reporting and for about 235 owners/operators, reporting of small
generation unit data.

    Respondent's obligation to respond: Under this proposed action, the
EPA estimates that 85 governmental entities would be required to report
to EPA. Authority for such collection is provided by CAA sections 110,
114, 172, 182, 187, 189, and 301(a). In addition, owners/operators
would be required to report data to EPA, and authority for these
collections is provided by the same CAA sections. Additionally, 7
railroad companies are expected to voluntarily provide data to the EPA
once every three years but would be under no obligation to do so.
    Estimated number of respondents: During the 2024-2026 period, the
EPA expects 85 governmental entities, owners/operators from an
estimated 14,233 facilities (13,420 to States and 819 to EPA), and
owners/operators of 7 railroads to respond. The description above
provides additional detail on the numbers and types of respondents for
the draft ICR period and for subsequent periods.
    Frequency of response: States would submit emissions data annually,
with more data required every third year. Owners/operators of
facilities within Indian country would report each year, starting in
2026 (for the 2025 emissions inventory year). The frequency of source
test data reports depends on the testing requirements set by the EPA
and States. Frequency can range from several times per year to once
every several years. However, for the purpose of the draft ICR, the EPA
estimates that owners/operators reporting source test data would report
an average of 3 source tests per year. Starting in 2027, the States and
owners/operators of facilities affected by this proposed rule would
report the same amount of point source data every year. Also starting
in 2027, States would report prescribed burning data each year. No
change is being proposed to triennial reporting frequency for nonpoint
and mobile sources.
    Total estimated burden: All burden estimates include additional
burden associated with proposed options included in the preamble (or
the most costly option when multiple options are described). Table 6
includes total estimated burden split by respondent, activity, and
mandatory or voluntary activities. Total estimated burden for all
entities combined is 1,142,927 hours for mandatory activities and
99,115 for voluntary hours during the 3-year period of this ICR. Of
this, the estimated burden for States is 317,454 hours for mandatory
activities and 99,087 for voluntary activities. Estimated burden for
owners/operators is 825,473 hours for mandatory activities and 28 hours
for voluntary activities. Burden is defined at 5 CFR 1320.3(b).
BILLING CODE 6560-50-P

[GRAPHIC] [TIFF OMITTED] TP09AU23.035

BILLING CODE 6560-50-C
    The draft ICR additionally provides, via Appendix C, State and
owner/operator hours and costs associated with emissions data
activities for SIP preparation, in compliance with OMB expectations
that the EPA include those costs. Since those costs are not burden
associated with the proposed revisions to the AERR, they are not
included in Table 6, but are noted here as EPA

requests comment on the burden estimates.
    Total estimated cost: Annual capital or operation & maintenance
costs include costs for the EPA and States. The EPA's expected annual
capital costs for its data systems needed from 2024 through 2026 are
$600,000. EPA's additional annual system development, operations, and
maintenance costs are expected to be $3,625,000. States' total
annualized capital costs are estimated to be $127,500, and their
operation and maintenance costs about $10,156,000.
    An agency may not conduct or sponsor, and a person is not required
to respond to a collection of information unless it displays a
currently valid OMB control number. The OMB control numbers for EPA's
regulations in 40 CFR part 51 are listed in 40 CFR part 9.
    Submit your comments on the agency's need for this information, the
accuracy of the provided burden estimates, and any suggested methods
for minimizing respondent burden to the EPA using the docket identified
at the beginning of this rule. You may also send your ICR-related
comments to OMB's Office of Information and Regulatory Affairs via
email to [email protected], Attention: Desk Officer for EPA.
Since OMB is required to make a decision concerning the ICR between 30
and 60 days after receipt, OMB must receive comments no later than
September 8, 2023. The EPA will respond to any ICR-related comments in
the final rule.

C. Regulatory Flexibility Act

    Pursuant to Section 603 of the RFA, the EPA prepared an initial
regulatory flexibility analysis (IRFA) that examined the impact of the
proposed rule on small entities along with regulatory alternatives that
could minimize that impact. The complete IRFA is available for review
in the docket (see Chapter 4 of the RIA in the docket for this
proposal) and is summarized here. The EPA is soliciting comment on the
presentation of its analysis of the impacts on small entities. As
required by Section 604 of the RFA, the EPA will prepare a final
regulatory flexibility analysis (FRFA) for this action as part of the
final rule. The FRFA will address the issues raised by public comments
on the IRFA.
    EPA is considering this proposal to fill gaps in the existing
available emissions inventory data, most notably for HAPs, prescribed
burning, and small generation units related to HEDD events. The HAP
data collection supports improved understanding of pollutants
surrounding at-risk communities. Additionally, the proposed revisions
to the AERR would further streamline air emissions reporting, allow for
improved consistency of emissions calculation methods, quality, and
transparency of state-provided data.
    Through this proposal, the EPA will have improved emissions data on
which to make decisions affecting implementation of the Clean Air Act
for both the air toxics program and the NAAQS. As described in section
III of this proposal, the EPA is proposing these amendments pursuant to
its authority under CAA sections 110, 111, 112, 113, 114, 129, 172,
182, 187, 189, and 301 (see also section III of this proposal).
Further, EPA's proposed action supports better understanding of
pollution to inform the EPA as it works to include environmental
justice considerations as described by E.O. 12898 (see also section
IV.A.1 of this preamble).
    EPA estimates that small entities will be affected by this proposal
when they are major sources, and for non-major sources, have primary
NAICS as listed in section II of this proposal. The EPA estimates that
approximately 34,800 small entities could be impacted by this rule
based on the CAA definition that the EPA proposes to use for this rule.
That number would increase to approximately 44,600 if the EPA were to
use the SBA definition.
    Based on this proposal, affected small entities would need to
report unit-level information about their facilities and report
facility-wide emissions in most circumstances. The small business
accommodation that this proposal offers to small businesses to report
with less detail could be eliminated for certain facilities if data
submitted in past inventory years shows, through EPA modeling, an
unacceptable level of risk. Small entities will need to be able to
record basic information about their facility such as fuel consumed by
certain activities, electricity used, amount of solvents consumed,
amount of product produced, or number of employees. Small entities will
additionally need to be able to enter this information in electronic
forms.
    The EPA has reviewed other EPA emissions reporting requirements for
duplication and is aware of the potential for duplication of limited
data elements for certain other EPA collections, though it is not aware
of any collection that is wholly or significantly duplicative. Further,
the EPA is actively working to avoid this duplication with its CAERS
development efforts. These potentially duplicative requirements include
40 CFR parts 75, 98, and 372. The EPA requests comment on whether this
list is comprehensive.
    EPA is considering a number of alternatives in this proposed rule
to minimize any significant economic impact of the proposed rule on
small entities. These proposed approaches are described in sections
IV.A.12 through IV.A.14 of this preamble. The EPA has included various
accommodations for small entities in the proposed rule based on
recommendations from the SBAR Panel Report, and these are additionally
reflected in the IRFA and proposed ICR.
    As required by Section 609(b) of the RFA, the EPA also convened a
Small Business Advocacy Review (SBAR) Panel to obtain advice and
recommendations from small entity representatives that potentially
would be subject to the rule's requirements. The SBAR Panel evaluated
the assembled materials and small-entity comments on issues related to
elements of an IRFA. A copy of the full SBAR Panel Report is available
in the rulemaking docket.

D. Unfunded Mandates Reform Act (UMRA)

    This action does not contain an unfunded mandate of $100 million or
more for State, local, or tribal governments as described in UMRA, 2
U.S.C. 1531-1538, and does not significantly or uniquely affect small
governments. This action does contain unfunded Federal mandates under
UMRA that may result in annual expenditures of $100 million or more for
the private sector. Accordingly, the costs and benefits associated with
this action are discussed in section IV.T of this preamble and in the
RIA, which is in the docket for this rule.

E. Executive Order 13132: Federalism

    This action does not have federalism implications. It will not have
substantial direct effects on the States, on the relationship between
the national government and the States, or on the distribution of power
and responsibilities among the various levels of government.

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

    This action has Tribal implications. However, it will neither
impose substantial direct compliance costs on federally recognized
Tribal governments, nor preempt Tribal law, and does not have
substantial direct effects on the relationship between the Federal
Government and Indian Tribes or on the distribution of power and
responsibilities between the Federal Government and Indian Tribes, as
specified in E.O. 13175. 65 FR 67249

(November 9, 2000). Consistent with the EPA Policy on Consultation and
Coordination with Indian Tribes, the EPA will provide Tribal officials
the opportunity to provide meaningful and timely input through
government-to-government consultation during the development of this
action. The majority of the facilities within Indian country expected
to be affected by this proposed action are owned by private entities.
For point sources, there would only be Tribal implications associated
with this rulemaking in the case where a unit is owned by a Tribal
government. The EPA notes that the reporting requirements for emissions
data proposed are unlikely to impose substantial costs. For nonpoint
sources, there would be Tribal implications for the proposed
requirements for how Tribes should report nonpoint emissions when
overlapping more than a single county within a State. Further, Tribal
implications may exist for the proposed provision that directs States
to include complete nonpoint source activity, inclusive of activity
within Indian country, when tribes overlapping State boundaries are not
required to report or optionally report nonpoint data to EPA.

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

    The EPA interprets Executive Order 13045 as applying only to those
regulatory actions that concern environmental health or safety risks
that the EPA has reason to believe may disproportionately affect
children, per the definition of ``covered regulatory action'' in
section 2-202 of the Executive Order. This action is not subject to
Executive Order 13045 because it does not concern an environmental
health risk or safety risk.

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

    This action is not a ``significant energy action'' because it is
not likely to have a significant adverse effect on the supply,
distribution or use of energy. Further, we have concluded that this
action is not likely to have any adverse energy effects because the
requirements to report emission data under this proposed action are
either already being met as part of the current AERR or would be a
small incremental impact on regulatory requirements for any facility
required to report emission data under this action. The EPA does not
anticipate that the provision described in section IV.D to collect
daily fuel usage data from States for sources with intermittent
electric generation would have any significant impact on the deployment
of such sources.

I. National Technology Transfer and Advancement Act

    This rulemaking does not involve technical standards.

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

    Executive Order 12898 (59 FR 7629, February 16, 1994) directs
federal agencies, to the greatest extent practicable and permitted by
law, to make environmental justice part of their mission by identifying
and addressing, as appropriate, disproportionately high and adverse
human health or environmental effects of their programs, policies, and
activities on communities with environmental justice concerns.
    The EPA believes that this type of action does not concern human
health or environmental conditions and, therefore, cannot be evaluated
with respect to potentially disproportionate and adverse effects on
communities with environmental justice concerns. This action would
update reporting requirements for State, local, and tribal entities and
add new reporting requirement for facilities for the collection of air
emissions data that are used to inform EPA's technical analysis of
impacts on human health and the environment.

K. Determinations Under CAA Section 307(b)(1) and (d)

    Section 307(b)(1) of the CAA governs judicial review of final
actions by the EPA. This section provides, in part, that petitions for
review must be filed only in the United States Court of Appeals for the
District of Columbia Circuit: (i) When the agency action consists of ''
any other nationally applicable regulations promulgated, or final
action taken, by the Administrator,'' or (ii) when such action is
locally or regionally applicable but ``such action is based on a
determination of nationwide scope or effect and if in taking such
action the Administrator finds and publishes that such action is based
on such a determination.'' The CAA reserves to the EPA complete
discretion to decide whether to invoke the exception in (ii) described
in the preceding sentence.\80\
---------------------------------------------------------------------------

    \80\ Sierra Club v. EPA, 47 F.4th 738, 745 (D.C. Cir. 2022)
(``EPA's decision whether to make and publish a finding of
nationwide scope or effect is committed to the Agency's discretion
and thus is unreviewable''); Texas v. EPA, 983 F.3d 826, 834-35 (5th
Cir. 2020).
---------------------------------------------------------------------------

    This proposed action, if finalized, would be ``nationally
applicable'' within the meaning of CAA Section 307(b)(1). In the
alternative, to the extent a court finds the action to be locally or
regionally applicable, the Administrator intends to exercise the
complete discretion afforded to him under the CAA to make and publish a
finding that the action is based on a determination of ``nationwide
scope or effect'' within the meaning of CAA Section 307(b)(1).\81\
---------------------------------------------------------------------------

    \81\ In deciding whether to invoke the exception by making and
publishing a finding that this action, if finalized, is based on a
determination of nationwide scope or effect, the Administrator
intends to take into account a number of policy considerations,
including his judgment balancing the benefit of obtaining the D.C.
Circuit's authoritative centralized review versus allowing
development of the issue in other contexts and the best use of
agency resources.
---------------------------------------------------------------------------

    This proposed action, if finalized, would implement a national
emissions data collection program in all 50 States, the District of
Columbia, U.S. territories, and Indian country, a geographic area that
spans all 10 EPA regions and 12 Federal judicial circuits. The proposed
action applies a uniform, nationwide approach to data collection and
interpretation of the various CAA provision discussed in this preamble
across all of these areas, and the proposed rule is based on a common
core of legal, technical, and policy determinations (as explained in
further detail in the following paragraph). For these reasons, this
proposed action, if finalized, would be nationally applicable.
    Alternatively, to the extent a court finds this proposal, if
finalized, to be locally or regionally applicable, the Administrator
intends to exercise the complete discretion afforded to him under the
CAA to make and publish a finding that the action is based on one or
more determinations of nationwide scope or effect for purposes of CAA
Section 307(b)(1).\82\ Specifically, the proposed rule is based on a
common core of statutory analysis, factual findings, and policy
determinations concerning the collection of emissions data from State,
local, and tribal agencies nationwide and from owners/operators of
emission sources located in those States, territories, and Indian
country. In addition, the technical, scientific, and engineering
information in support of the proposed emissions data collection
requirements relies on a

nationally consistent modeling methodology to set emissions reporting
thresholds, as set forth elsewhere in this proposed rule and in the
relevant supporting documents in the docket for this proposed rule.
---------------------------------------------------------------------------

    \82\ In the report on the 1977 Amendments that revised section
307(b)(1) of the CAA, Congress noted that the Administrator's
determination that the ``nationwide scope or effect'' exception
applies would be appropriate for any action that has a scope or
effect beyond a single judicial circuit. See H.R. Rep. No. 95-294 at
323, 324, reprinted in 1977 U.S.C.C.A.N. 1402-03.
---------------------------------------------------------------------------

    Therefore, pursuant to CAA section 307(b), any petitions for review
of this action, if and when it is finalized, must be filed in the D.C.
Circuit within 60 days from the date such final action is published in
the Federal Register.
    In addition, pursuant to CAA section 307(d)(1)(V), the EPA hereby
determines that this rulemaking action is subject to the requirements
of section 307(d).

List of Subjects

40 CFR Part 2

    Environmental protection, Emission data, Administrative practice
and procedure, Confidential business information, Courts, Freedom of
information, Government employees.

40 CFR Part 51

    Environmental Protection, Administrative practice and procedure,
Air pollution control, Emission data, Intergovernmental relations,
Criteria pollutants, Hazardous Air Pollutants, Ozone, Particulate
matter, Oxides of Nitrogen, Sulfur dioxide, Lead, Regional haze,
Reporting and record keeping requirements, Stationary sources, Mobile
sources, Prescribed fires.

Michael S. Regan,
Administrator.

    For the reasons stated in the preamble, title 40, chapter I, Part 2
of the Code of Federal Regulations is proposed to be amended and Part
51 is proposed to be revised as follows:

PART 2--[AMENDED]

0
1. The authority for part 2 continues to read as follows:

    Authority:  5 U.S.C. 552, 552a, 553; 28 U.S.C. 509, 510, 534; 31
U.S.C. 3717.

Subpart A--Procedures for Disclosure of Records Under the Freedom
of Information Act

0
2. Amend Sec.  2.301 by adding paragraph (k) to read as follows.

Sec.  2.301  Special rules governing certain information obtained under
the Clean Air Act.

* * * * *
    (k) Data submitted under 40 CFR part 51, subpart A.
    (1) Sections 2.201 through 2.215 do not apply to data submitted
under 40 CFR part 51, subpart A that the EPA has determined, pursuant
to 42 U.S.C. 7414 in a rulemaking subject to 42 U.S.C. 7607(d), to be
emission data as defined in paragraph (a)(2)(i) of this section.
    (2) The provisions of 40 CFR 2.201 through 2.215 continue to apply
for categories of reported information identified in 40 CFR part 51,
subpart A for which there is no emission data determination in 40 CFR
part 51, subpart A.

PART 51--[AMENDED]

0
3. The Authority citation for part 51 continues to read as follows:

    Authority:  23 U.S.C. 101; 42 U.S.C. 7401-7671q.

0
4. Subpart A of part 51 is revised to read as follows:

Subpart A--Air Emissions Reporting Requirements

    General Information for Inventory Preparers

Sec.  51.1  Who is responsible for what actions described in this
subpart?

    Both States \1\ and certain owners/operators of facilities emitting
``air pollutants'' (as defined by Sec.  51.50 of this subpart) are
subject to requirements included in this section.
---------------------------------------------------------------------------

    \1\ The term ``State'' is defined to include delegated local
agencies and tribes that have elected to seek treatment in the same
manner as a state (TAS) status and have obtained approval to
implement rules such as the AERR through a Tribal Implementation
Plan (TIP).
---------------------------------------------------------------------------

    (a) Owners and operators of facilities.
    (1) An owner/operator of a point source within a State's
implementation planning authority must report emissions data as
described by Sec.  51.25 of this subpart.
    (2) An owner/operator of a point source that is outside the
geographic scope of a State's implementation planning authority must
report emissions data as described by Sec.  51.27 of this subpart. This
could include owners/operators of facilities located within certain
portions of Indian country, owners/operators of (1) deepwater ports
subject to CAA requirements under the Deepwater Port Act, and (2)
owners/operators of OCS sources as defined in CAA section 328(a) with
the exception of owners/operators of facilities that are regulated
under 43 U.S.C. 1331 et seq. (the Outer Continental Shelf Lands Act)
and that are located (a) offshore of the North Slope Borough of the
State of Alaska, or (b) offshore of the United States Gulf Coast
westward of longitude 87 degrees and 30 minutes.
    (3) An owner/operator of a point source that collects source test
data or performance evaluations may need to report that data as
described by Sec. Sec.  51.25 and 51.27 of this subpart.
    (4) If the owner and operator of a facility are different parties,
only one party needs to report under this subpart.
    (b) Indian tribes with Treatment as a State status. An Indian tribe
(as defined by CAA section 302(r)) may elect to seek Treatment as State
(TAS) status as prescribed by the Tribal Authority Rule 40 CFR part 49,
subpart A. An Indian tribe may obtain approval to implement reporting
for this subpart through a Tribal Implementation Plan (TIP), but Indian
tribes are under no obligation to do so. Those Indian Tribes that have
obtained TAS status are subject to this subpart to the extent allowed
in their TIP. Accordingly, for an Indian Tribe that has applied for and
received TAS status for air quality control purposes and is subject to
the AERR under its TIP, the use of the term state in this subpart
should be read to include that tribal government.
    (c) State mandatory reporting.
    (1) A State must collect and report to the EPA criteria pollutant
and precursor emissions data from point sources (as defined by Sec.
51.50 of this subpart) as described by Sec.  51.15(a) of this subpart.
A State must collect and report data for all such sources within the
State's implementation planning authority, including any offshore areas
within State waters or within any Federal waters for which a State
agency has delegated authority. A lack of State permitting for point
sources or pollutants associated with them does not exempt a facility
or pollutant from being reported.
    (2) A State must report to the EPA data from airports as described
by Sec.  51.15(b) of this subpart.
    (3) A State must report to the EPA rail yard data as described by
Sec.  51.15(c) of this subpart.
    (4) A State must report to the EPA nonpoint source data as
described by Sec.  51.15(d) of this subpart.
    (5) A State must report to the EPA mobile source data as described
by Sec.  51.15(e) of this subpart.
    (6) A State must report data about certain prescribed burning (as
defined by 40 CFR 51.301) to the EPA (as described by Sec.  51.15(f) of
this subpart) for those prescribed burns that meet the following
criteria:
    (i) The prescribed burn is not an agricultural burn or a land
clearance burn (as defined by Sec.  51.50 of this subpart); and
    (ii) The prescribed burn occurs on State lands or military lands,
excluding prescribed burns on such lands conducted by Federal Land
Managers (as defined by CAA 302(i)); and

    (iii) The prescribed burn is one of the following:
    (A) A broadcast burn or understory burn that impacts at least 50
acres; and/or
    (B) A pile burn that includes biomass from at least 25 acres; and/
or
    (C) A prescribed burn that includes pile burning as well as other
prescribed burn types that in total collects biomass from or burns at
least 25 acres.
    (7) EPA urges State environmental agencies to coordinate with State
forestry agencies to collect, obtain, and report the data described by
Sec.  51.1(c)(6). A lack of State permitting requirements or other
planning processes does not exempt a prescribed burn from being
reported.
    (d) State optional reporting.
    (1) For inventory years 2026 and later, a State that intends to
collect and report hazardous air pollutants (HAP) on behalf of owners/
operators for a given emissions inventory year must:
    (i) Promulgate a State regulation to collect facility inventory and
actual annual emissions data for HAP to meet the requirements for
owners/operators by:
    (A) Replicating requirements on owners/operators from Sec.  51.5 of
this subpart, excluding paragraphs Sec.  51.5(h) and (i);
    (B) Ensuring the definition of point sources is consistent with
Sec.  51.50 of this subpart;
    (C) Ensuring reporting of all HAP as described by Sec.  51.12(b) of
this subpart and requirements for specific situations described by
Sec.  51.12(d) and (e) of this subpart;
    (D) Ensuring reporting of incidental criteria pollutants and
precursors as described by Sec.  51.12(c) of this subpart;
    (E) Including the timing for point source reporting from owners/
operators to the State as described by Sec.  51.30 of this subpart; and
    (F) Ensuring reporting of all required data elements as described
by Sec.  51.40(a) and (b) of this subpart.
    (ii) Apply to the EPA in writing by March 31 of the first inventory
year for which the State intends to report emissions data for HAP
(e.g., for the 2026 emissions inventory year, a State must apply by
March 31, 2026) by providing citations to the State regulation for each
of the elements listed in Sec.  51.1(d)(1)(i).
    (2) The EPA will notify a State as expeditiously as possible
regarding its application, any needed adjustments, and post final
approval decisions on the EPA Air Emissions Inventories website
(https://epa.gov/air-emissions-inventories) for use by the State and
owners/operators.
    (3) A State must reapply for HAP reporting approval when one or
more of the following events occurs:
    (i) The State changes its emissions inventory reporting
requirements related to any aspect of the application requirements
described by Sec.  51.1(d)(1)(i) of this subpart.
    (ii) EPA revises requirements of this subpart for pollutants
described by Sec.  51.12 (b) through (e) of this subpart, HAP reporting
thresholds (for which the initial reporting thresholds are presented in
Table 1B to Appendix A of this subpart) or the associated required data
elements as described by Sec.  51.40.
    (iii) The EPA notifies a State in writing that a new application is
required for any reason, including that the State failed to meet any
requirement of this subpart.
    (4) If a State intends to use or integrate with the Combined Air
Emissions Reporting System (CAERS) for a particular inventory year, the
State should notify the EPA of this intent by two months prior to start
of the inventory year (e.g., for the 2024 inventory year, a State
should notify the EPA by November 1, 2023).
    (5) If a State intends to stop collecting and reporting HAP for
point sources, the State must notify the EPA in writing by November 1
of the year prior to the inventory year (e.g., for the 2024 inventory
year, a State must notify the EPA by November 1, 2023).
    (6) The EPA approval for a State to report HAP remains effective
for subsequent inventory years until the EPA revokes that approval and
transfers responsibility back to owners/operators.
    (e) The State (as defined by CAA section 302(d)) may authorize a
municipality (as defined by CAA section 302(f)) to fulfill the data
collection and reporting requirements of this subpart on behalf of the
State and to submit data to the EPA for emissions within that
municipality's authority. Such authorization does not relieve the State
of responsibility for carrying out the applicable requirements of this
subpart. Accordingly, for municipalities that have obtained authority
to collect and report under this subpart, the use of the term ``State''
in this subpart should be read to include that municipality.

Sec.  51.5  What data, tools and other considerations apply for
emissions reporting?

    The requirements in this section are effective starting with
different inventory years, as follows: Paragraphs (b) through (f) of
this section are effective starting with the 2026 inventory year. All
other paragraphs are effective starting with the 2023 inventory year.
    (a) A State or owner/operator must estimate annual actual emissions
as defined in Sec.  51.50 of this subpart using the best available
estimation methods for assessing whether its facility emissions exceed
the emissions reporting thresholds in Tables 1A and 1B to Appendix A of
this subpart and for submitting point source emissions data under this
subpart. The ``Introduction to the EPA Compilation of Air Pollutant
Emissions Factors (AP-42)'' \2\ describes many techniques for
calculating emissions and provides on page 4 a hierarchy of emissions
estimation methods. For the purposes of this subpart, a State or owner/
operator should preferentially use available emissions calculation
methods at the top of the hierarchy over emissions calculation
approaches lower in the hierarchy. Where current the EPA guidance
materials are outdated or are not applicable to sources or source
categories, an owner/operator (other than a small entity, as defined by
Sec.  51.50 of this subpart) should develop and document new techniques
for estimating emissions, which should rely on any available source
measurements applicable to the emissions source(s).
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    \2\ https://epa.gov/air-emissions-factors-and-quantification/ap-42-compilation-air-emissions-factors.
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    (b) A State or owner/operator must include emissions from mobile
sources (excluding aircraft and ground support equipment) operating
primarily within the facility site boundaries of a point source or
multiple adjacent point sources when assessing whether its facility
emissions exceed the emissions reporting thresholds in Tables 1A and 1B
to Appendix A of this subpart and when submitting point source
emissions data under this subpart.
    (c) An owner/operator submitting emissions data directly to the EPA
under this subpart must use continuous monitor data applicable to the
units and processes that operated during the reporting year to
calculate annual actual emissions. In the absence of monitored data, an
owner/operator must use the most recent source test(s) applicable to
the operating conditions of the units and processes during that year to
estimate annual actual emissions. An owner/operator should determine
which source test data should be included to best estimate annual
actual emissions. If a facility has source tests, performance
evaluations, or continuous emissions monitoring data for a unit or
process that operated during the reporting year and the owner/operator
does not use

that data to estimate annual emissions, then the owner/operator must
submit a justification for that choice for each unit and pollutant for
which such data are not used to estimate emissions.
    (d) A State submitting point source emissions on behalf of owners/
operators under this subpart must ensure that owners/operators of
facilities submitting data to the State take the same approaches as
described in paragraph Sec.  51.5(a) through (c) of this subpart. If a
State submits data for an owner/operator who has not used available
source test data or continuous monitor data to estimate emissions, then
the State must submit a justification for each unit and pollutant for
which such data are not used to estimate emissions.
    (e) When source tests, performance tests, or continuous emissions
monitor data are not available, a State and owner/operator may use
emission rates from the EPA compilations of emission factors such as
WebFIRE and AP-42 to estimate emissions. An owner/operator may also use
emission factors provided by States. To estimate emissions from point
sources, a State or owner/operator should use emission factors that
represent the emissions process and controls at the facility. If
existing emission factors are insufficient for developing
representative annual actual emissions, a State or owner/operator
(other than a small entity, as defined by Sec.  51.50 of this subpart)
should develop new emission factors through emission testing of point
sources when existing EPA source test methods are available.
    (f) When data described in paragraphs (c), (d), and (e) of this
section are not available, a State or owner/operator may use the
SPECIATE database \3\ or other credible, publicly available speciation
profile data to calculate ratios of related pollutants if relevant
speciation profiles are available. Starting with the 2026 inventory
year, when using a speciation profile, a State or owner/operator must
provide the speciation profile code with their data. When estimating
emissions using speciation data, the emissions data must include:
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    \3\ SPECIATE Database available at https://epa.gov/air-emissions-modeling/speciate.
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    (1) The most applicable emissions calculation method indicating the
type of speciation profile used;
    (2) The speciation factor used in the calculation, reported as the
emission factor;
    (3) The pollutant code that identifies the pollutant used to
calculate another pollutant, reported as the denominator of the
emission factor;
    (4) The pollutant code that identifies the pollutant calculated
from the speciation profile, reported as the numerator of the emission
factor;
    (5) The emissions value and associated required data elements for
the pollutant identified in Sec.  51.5(f)(3), reported as an annual
emissions value even if that pollutant is not otherwise required (e.g.,
Total organic gases); and
    (6) In the case of a SPECIATE profile, the profile code reported as
the emission factor comment, or in the case of other speciation
profiles, the journal citation or reference to a publicly available
report reported as the emission factor comment.
    (g) A State must report data using the Emissions Inventory System
(EIS) or analogous electronic reporting approach provided by the EPA to
report data required by this subpart. Submission to the EIS can be done
using EPA's Central Data Exchange (CDX).\4\ Unless otherwise noted in
this section, the EPA provides states information about reporting data,
required and optional data fields, and explains how to access all data
needed for reporting to EIS as part of a NEI plan available at https://epa.gov/air-emissions-inventories/national-emissions-inventory-nei.
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    \4\ Central Data Exchange is available at https://cdx.epa.gov/.
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    (h) An owner/operator reporting directly to the EPA under this
subpart must use the Combined Air Emissions Reporting System (CAERS) or
analogous electric reporting approach provided by the EPA to report
emissions data. The EPA provides owners/operators information about
reporting data, required and optional data fields, and explains how to
access to all data needed for reporting with CAERS at https://epa.gov/air-emissions-inventories.
    (i) An owner/operator reporting directly to the EPA under this
subpart must use the Compliance and Emissions Data Reporting Interface
(CEDRI) to report source test data and performance reports as required
by Sec. Sec.  51.25 and 51.27 or use an analogous electronic reporting
approach provided by the EPA. CEDRI can be accessed through the CDX.\4\
CEDRI works with the EPA's Electronic Reporting Tool (ERT) available
from EPA's ERT website (https://epa.gov/electronic-reporting-air-emissions/electronic-reporting-tool-ert). A list of test methods,
performance evaluations, and pollutants compatible with the Electronic
Reporting Tool (ERT), as well as the date on which those methods or
performance evaluations were available on the ERT, is available from
the EPA via the ERT website https://epa.gov/system/files/documents/2021-09/ert-compatible-methods-and-pollutants.pdf).
    (j) A State or owner/operator of point sources reporting under this
subpart must use the most current data reporting codes for electronic
reporting that are available at the time of reporting. Reporting codes
can change over time, and the EPA will strive to publish the EIS
reporting codes that can be used for each inventory year by June 30 of
inventory year. For example, the EPA would plan to publish by June 30,
2024, codes that are to be used for reporting 2024 emissions. Codes are
published by the EPA as follows:
    (1) Source classification codes (SCCs) can be obtained from the EPA
SCC website (https://epa.gov/scc). Materials provided on this website
explain what to do if a SCC is not available for an emissions process;
and
    (2) Other reporting codes are available through EPA's electronic
reporting data systems (e.g., EIS and CAERS), and the EPA may make them
available through references within the NEI plan for each inventory
year.
    (k) The EPA provides States for their use nonpoint emissions
calculation methods, associated tools/spreadsheets, and draft activity
and emissions data for nonpoint sources, point source aircraft, and
point source rail yards. The nonpoint information includes approaches
and data based on county totals for commercial marine vessels that are
treated in this subpart as nonpoint sources for reporting purposes. The
EPA provides on its Air Emissions Inventories website (https://epa.gov/air-emissions-inventories) an NEI Plan that includes directions for
which methods, tools, and models should be used and instructions for
accessing data described in this paragraph.
    (l) The EPA provides the Motor Vehicle Emissions Simulator (MOVES)
model including quality assurance tools for input data at the MOVES
website (https://epa.gov/moves). The EPA also provides draft and final
onroad and nonroad emissions data based on the MOVES model. States,
except for California, must use MOVES model input formats and the
quality assurance tools or the same for the latest available on-road
and nonroad EPA models to meet the requirements of Sec.  51.15(e). The