develop the emission limits for the HON sources. Multiple stack tests
included values below the detection level for certain dioxins and
furans congeners. Therefore, we evaluated the RDL and calculated a
three times the RDL value of 0.054 ng/dscm at 3 percent oxygen (toxic
equivalency basis). Since the HON has well over 30 sources (i.e., 634
CMPUs), we calculated the existing source UPL using data from the top
two facilities (i.e., nine times 12 percent rounds up to two) and
calculated the new source UPL using data from the best performer. The
existing source UPL was calculated as 0.032 ng/dscm at 3 percent oxygen
(toxic equivalency basis) and the new source UPL equaled 0.031 ng/dscm
at 3 percent oxygen (toxic equivalency basis). For both existing
sources and new sources, the three times the RDL value for dioxins and
furans was greater than the calculated UPL. As such, we are proposing
at 40 CFR 63.113(a)(5) that the dioxins and furans emissions limit for
HON facilities is the three times the RDL value of 0.054 ng/dscm at 3
percent oxygen (toxic equivalency basis). To ensure compliance with
this limit, we are proposing performance testing requirements that
include the use of Method 23 of 40 CFR part 60, appendix A-7 at 40 CFR
63.116(h). We are also proposing a definition for the term ``dioxins
and furans'' at 40 CFR 63.101 to mean total tetra--through
octachlorinated dibenzo-p-dioxins and dibenzofurans. Finally, we are
proposing owners and operators comply with the same monitoring,
recordkeeping, and reporting requirements that are already required for
compliance with the current process vent standards. We did not identify
additional controls or perform a beyond-the-floor analysis for reducing
dioxins and furans emissions further because the proposed emission
limit is based on the detection limit of the method and represents the
lowest concentration of dioxins and furans that can be measured;
therefore no further reductions can be achieved that are measurable. We
solicit comment on the proposed standards for dioxins and furans for
the HON, P&R I, and P&R II. For details on the emission limit
calculations, see the document titled Dioxins and Furans MACT Floor in
the SOCMI Source Category for Processes Subject to HON and Processes
Subject to Group I and Group II Polymers and Resins NESHAPs, which is
available in the docket for this rulemaking.
    Dioxins and furans stack test data are not available for P&R I and
P&R II facilities, and in our review of reported emissions inventories,
none of these facilities reported emissions of these pollutants from
these source categories. However, given that neoprene production
facilities and epichlorohydrin facilities in P&R I and all facilities
in P&R II have chlorinated chemicals that could be controlled with
combustion controls, the mechanism of formation of dioxins and furans
is the same as for HON sources controlling chlorinated SOCMI chemicals.
Given that no facilities are reporting emissions of these pollutants in
their inventories, we believe that the best performing sources that
would constitute the MACT floor would have emissions below three times
the RDL, which would be the lowest MACT emission standard the EPA would
set due to measurement limitations. Thus, we are proposing dioxins and
furans emissions limits for P&R I and P&R II facilities using,
producing, or emitting chlorinated chemicals that are the same as we
are proposing for the HON (i.e., 0.054 ng/dscm at 3 percent oxygen,
toxic equivalency basis). We are proposing the dioxins and furans
emission limit for P&R I at 40 CFR 63.485(x) (which points to 40 CFR
63.113(a)(5) for continuous front-end process vents) and 40 CFR
63.487(a)(3) and (b)(3) (for batch front-end process vents); and the
P&R II emission limit at 40 CFR 63.523(e) (for process vents associated
with each existing, new, or reconstructed affected BLR source), 40 CFR
63.524(a)(3) (for process vents associated with each existing affected
WSR source), and 40 CFR 63.524(b)(3) (for process vents associated with
each new or reconstructed affected WSR source). To ensure compliance
with the proposed limit, we are proposing performance testing
requirements that include the use of Method 23 of 40 CFR part 60,
appendix A-7 at 40 CFR 63.485(x) (which points to 40 CFR 63.116(h) for
P&R I continuous front-end process vents) and 40 CFR 63.490(g) (for P&R
I batch front-end process vents) and 63.525(m) (for P&R II sources). We
are also proposing a definition for the term ``dioxins and furans'' at
40 CFR 63.482 (for P&R I sources) and 40 CFR 63.522 (for P&R II
sources) to mean total tetra--through octachlorinated dibenzo-p-dioxins
and dibenzofurans. Finally, we are proposing owners and operators
comply with the same monitoring, recordkeeping, and reporting
requirements that are already required for compliance with the current
process vent standards. We solicit comment on the types of emission
controls used and stack test data for emissions of dioxins and furans
from the P&R I and P&R II source categories.
    To evaluate the cost impacts of the proposed emissions limits, we
assumed select facilities would install a condenser prior to the
existing control device (e.g., thermal oxidizer) to remove chlorinated
compounds from the stream and prevent the formation of dioxins and
furans in the thermal oxidizer. Of the nine HON facilities with stack
test data, two facilities do not meet the proposed emission limit and
would need to install a condenser to reduce dioxins and furans
emissions.\140\ For the twelve HON facilities that do not have stack
test data available, we assumed that five facilities would not meet the
emission limits and would need to install a condenser to reduce their
emissions. We assumed the one P&R I facility with dioxins and furans
emissions in the risk modeling file and all five P&R II facilities
would need to install a condenser to meet the dioxins and furans
emissions limit. Based on our cost assumptions, the nationwide costs to
comply with the dioxins and furans emissions limits are $3.9 million in
capital costs and $2.3 million in annual costs for the HON; $0.56
million in capital costs and $0.33 million in annual costs for P&R I;
and $2.8 million

in capital costs and $1.6 million in annual costs for P&R II.
---------------------------------------------------------------------------

    \140\ Note that four facilities do not meet the dioxins and
furans emission limit in our dataset, however two of the four
facilities are subject to 40 CFR part 63, subpart HHHHHHH, and are
complying with a 0.051 ng/dscm at 3 percent oxygen, toxic
equivalency basis, limit for PVC-combined process vents and are
using the same control device for emissions from HON processes.
---------------------------------------------------------------------------

    We solicit comment on all aspects of the proposed emissions limits
for dioxins and furans. See the document titled Dioxins and Furans MACT
Floor in the SOCMI Source Category for Processes Subject to HON and
Processes Subject to Group I and Group II Polymers and Resins NESHAPs,
which is available in the docket for this rulemaking, for details on
the assumptions and methodologies used in the analyses.
6. Pressure Vessels
    We are proposing new requirements for pressure vessels that are
associated with processes subject to the HON or P&R I. The EPA is
proposing to define pressure vessel at 40 CFR 63.101 (for HON) and 40
CFR 63.482 (for P&R I) to mean ``a storage vessel that is used to store
liquids or gases and is designed not to vent to the atmosphere as a
result of compression of the vapor headspace in the pressure vessel
during filling of the pressure vessel to its design capacity.'' To
eliminate any ambiguity in applicability or control requirements, the
EPA is also proposing 40 CFR 63.101 (for HON) and 40 CFR 63.482 (for
P&R I) to remove the exemption for ``pressure vessels designed to
operate in excess of 204.9 kilopascals and without emissions to the
atmosphere'' from the definition of storage vessel.\141\ This long-
standing exemption is ambiguous with respect to what ``without
emissions to the atmosphere'' means. For example, most pressure vessels
have relief devices that allow for venting when pressure exceeds
setpoints. In many cases, these vents are routed to control devices;
however, control devices are not completely effective (e.g., achieve 98
percent control), and therefore there are emissions to the atmosphere
from these pressure vessels, even if they are controlled. There are
also instances where other components in pressure systems may allow for
fugitive releases because of leaks from fittings or cooling systems.
All of these events arguably are ``emissions to the atmosphere'' and
therefore it is likely that even if this exemption were maintained,
owners and operators of pressure vessels would still have uncertainty
regarding whether or not they were subject to substantive requirements.
Therefore, the proposed revisions remove the ambiguity associated with
the exemption and set standards intended to limit emissions to the
atmosphere from pressure vessels. Given that we have seen large
emission events from PRDs on pressure vessels (e.g., a 155 tpy 1,3-
butadiene atmospheric PRD release was documented from a HON pressure
vessel in 2015),\142\ we are also proposing at 40 CFR 63.119(a)(7)(v)
and 40 CFR 63.484(t) that any atmospheric PRD release from a pressure
vessel is a deviation of the PRD work practice standards (see section
III.D.2 of this preamble for more information on the proposed PRD work
practice standards).
---------------------------------------------------------------------------

    \141\ We note that P&R II does not have a pressure vessel
exemption in its definition of storage tank (see 40 CR 63.522).
    \142\ See the Appendix to the document titled Cost and Emissions
Impacts for Pressure Vessels Located in the SOCMI Source Category
that are Associated with Processes Subject to HON and for Pressure
Vessels Subject to the Group I Polymers and Resins NESHAP, which is
available in the docket for this rulemaking.
---------------------------------------------------------------------------

    We are proposing LDAR requirements at 40 CFR 63.119(a)(7) (for HON)
and 40 CFR 63.484(t) (for P&R I) that are based on similar no-
detectable emission requirements required for closed vent systems in
most chemical sector NESHAP. These requirements are consistent with CAA
section 112(d) controls and reflect the MACT floor. As such, these
proposed requirements impose a standard that requires no detectable
emissions at all times (i.e., would be required to meet a leak
definition of 500 ppm at each point on the pressure vessel where total
organic HAP could potentially be emitted); require initial and annual
leak monitoring using EPA Method 21 of 40 CFR part 60, Appendix A-7;
and require routing organic HAP through a closed vent system to a
control device (i.e., no releases to the atmosphere through a pressure
vessel's PRD). The proposed standards recognize that pressure vessels
can be designed with appropriate capture and containment systems for
leak interfaces and pressure vessel PRDs such that the owner or
operator can avoid ``willful'' deviations. We also did not identify any
additional options beyond those identified above (i.e., beyond-the-
floor options) for minimizing emissions to the atmosphere from pressure
vessels.
    Based on facility responses to our CAA section 114 request, we
estimate that there could be up to one pressure vessel per every two
CMPUs for a total of 317 pressure vessels requiring emissions control
under the HON nationwide (1 pressure vessel per 2 CMPUs x 634 CMPUs =
317 pressure vessels). We also estimate that there are nine P&R I
facilities that each have one pressure vessel (for a total of nine
pressure vessels requiring emissions control under P&R I nationwide)
given that: (1) We are aware of three P&R I facilities within the
polybutadiene rubber source category that each have a pressure vessel,
(2) there are five P&R I facilities that make styrene butadiene rubber
and are therefore likely to each have one 1,3-butadiene pressure
vessel, and (3) we are aware of one other pressure vessel (storing EtO)
located at a P&R I facility producing epichlorohydrin elastomer. Using
information from a 2012 analysis that identified developments for
storage vessels at chemical manufacturing facilities and petroleum
refineries,\143\ we estimate a total HAP emission reduction of 244 tpy
for all affected pressure vessels associated with processes subject to
the HON and 6.9 tpy HAP for pressure vessels subject to P&R I; the
nationwide capital cost for the proposed pressure vessel LDAR
requirements for the HON is about $78,000 and the annualized capital
costs is $73,000, and for P&R I the nationwide capital cost is $2,200
and the annualized capital costs is about $2,000. See the document
titled Cost and Emissions Impacts for Pressure Vessels Located in the
SOCMI Source Category that are Associated with Processes Subject to HON
and for Pressure Vessels Subject to the Group I Polymers and Resins
NESHAP, which is available in the docket for this rulemaking, for
details on the assumptions and methodologies used in this analysis. We
solicit comment on the proposed revisions for pressure vessels.
---------------------------------------------------------------------------

    \143\ Randall, 2012. Memorandum from Randall, D., RTI
International to Parsons, N., EPA/OAQPS. Survey of Control
Technology for Storage Vessels and Analysis of Impacts for Storage
Vessel Control Options. January 20, 2012. EPA Docket No. EPA-HQ-OAR-
2010-0871.
---------------------------------------------------------------------------

7. Surge Control Vessels and Bottoms Receivers
    The HON and P&R I define a surge control vessel to mean feed drums,
recycle drums, and intermediate vessels. Surge control vessels are used
within a CMPU or an EPPU when in-process storage, mixing, or management
of flow rates or volumes is needed to assist in production of a
product. The HON and P&R I define a bottoms receiver as a tank that
collects distillation bottoms before the stream is sent for storage or
for further downstream processing. Surge control vessels and bottoms
receivers are not considered storage vessels under the HON and P&R I
because they are covered by the equipment leak provisions. Although
these emissions sources are regulated under the equipment leak
provisions (i.e., NESHAP subpart H), the equipment leak requirements
point back to the storage vessel requirements in NESHAP subpart G.
Owners and operators of surge

control vessels and bottoms receivers are required to comply with the
HON storage vessel requirements in NESHAP subpart G (i.e., use a
floating roof or route emissions to closed vent system and control to
get 95 percent control) provided the surge control vessel or bottoms
receiver meets certain capacity and vapor pressure requirements. For
HON and P&R I surge control vessels and bottoms receivers at existing
sources, storage vessel control requirements apply if the capacity is
between 75 m\3\ and 151 m\3\ and the MTVP is greater than or equal to
13.1 kPa, or the capacity is greater than or equal to 151 m\3\ and the
MTVP is greater than or equal to 5.2 kPa. For HON and P&R I surge
control vessels and bottoms receivers at new sources, storage vessel
control requirements apply if the capacity is between 38 m\3\ and 151
m\3\ and the MTVP is greater than or equal to 13.1 kPa, or the capacity
is greater than or equal to 151 m\3\ and the MTVP is greater than or
equal to 0.7 kPa. The HON and P&R I exclude all other surge control
vessels and bottoms receivers from emissions control requirements.
    We are proposing at 40 CFR 63.170(b) (for HON) and 40 CFR 63.485(d)
(for P&R I) that owners and operators of all surge control vessels and
bottoms receivers that emit greater than or equal to 1.0 lb/hr of total
organic HAP would be required to reduce emissions of organic HAP using
a flare meeting the proposed operating and monitoring requirements for
flares (see section III.D.1 of this preamble); or reduce emissions of
total organic HAP or TOC by 98 percent by weight or to an exit
concentration of 20 ppmv, whichever is less stringent. These
requirements are consistent with CAA section 112(d) controls and
reflect the MACT floor.\144\ Emissions from surge control vessels and
bottoms receivers are characteristic of process vents, not emissions
from storage vessels. These vessels operate at process temperatures,
not ambient storage temperatures; typically do not undergo level
changes that larger storage vessels undergo; and are most often
operated under pressure with and without non-condensable gases flowing
into and out of them. The size of these vessels is also typically not
correlated with emissions, as are storage vessels. We did not identify
any additional options beyond those identified above (i.e., beyond-the-
floor options) for controlling emissions from surge control vessels and
bottoms receivers. We solicit comment on the proposed revisions for
surge control vessels and bottoms receivers.
---------------------------------------------------------------------------

    \144\ They also represent the level of control found to be cost-
effective for process vents and that we are proposing for HON
process vents under technology review in section III.C.3 of this
preamble.
---------------------------------------------------------------------------

8. Transfer Operations (for HON)
    Generally, transfer operations refer to the equipment (e.g.,
transfer racks) that are used to transfer materials (primarily liquid
products) from the facility, typically from storage vessels, into
transport vehicles, portable cargo units, and marine vessels that are
used to carry the material to another site or location. The combination
of the transfer rack, storage vessel, connecting piping, and equipment
used/on the connecting piping are typically part of the process unit or
affected source in existing regulations. The HON regulates transfer
operations at 40 CFR 63.126 through 40 CFR 63.130. Transfer operations
are defined in the HON at 40 CFR 63.101 to mean the loading, into a
tank truck or railcar, of organic liquids that contain one or more of
the organic HAP listed in table 2 to NESHAP subpart F from a transfer
rack; and transfer operations do not include loading at an operating
pressure greater than 204.9 kPa. Transfer racks are also defined in the
HON at 40 CFR 63.101. Under the HON, transfer racks mean the collection
of loading arms and loading hoses, at a single loading rack, that are
assigned to a CMPU subject to NESHAP subpart F according to the
procedures specified in 40 CFR 63.100(h) and are used to fill tank
trucks and/or railcars with organic liquids that contain one or more of
the organic HAP listed in table 2 to NESHAP subpart F. A transfer rack
includes the associated pumps, meters, shutoff valves, relief valves,
and other piping and valves, but does not include: (1) Racks, arms, or
hoses that only transfer liquids containing organic HAP as impurities;
(2) racks, arms, or hoses that vapor balance during all loading
operations; or (3) racks transferring organic liquids that contain
organic HAP only as impurities.
    In general, when the equipment and operations are physically
separate (i.e., do not share common piping, valves, and other
equipment), the transfer racks are considered separate transfer racks.
Transfer rack emissions depend on several factors, including the
physical and chemical characteristics of the liquid being loaded, the
quantity of material loaded, and the loading conditions. Primarily,
these characteristics boil down to the volatility (or vapor pressure)
and molecular weight of the liquid being transferred, the temperature
and pressure conditions of the transfer operation, the loading method
employed (e.g., submerged loading versus splash loading), and the
volume of material transferred. In addition, during the loading of
liquid into transport vehicles, VOC and HAP vapors present in the
transport vehicle are displaced by the liquid being loaded. The vapors
in the transport vehicle include either vapors generated as the liquid
is being loaded, and/or vapors remaining from residual commodity or
liquid from the previous load (if present). For uncontrolled
operations, transfer rack emissions typically occur at the loading
hatch or opening of the transport vehicle. Emissions can also occur
from leaks in the transport vehicle. The rate at which these VOC and
HAP are emitted varies depending on which type of transport vehicle is
being loaded (tank truck or railcar), whether the transport vehicle was
empty before filling or refilled while still containing a heel and
vapors, the physical and chemical characteristics of the liquid being
loaded, and the type of loading method used.
    Owners and operators of each HON transfer rack that annually loads
greater than or equal to 0.65 million liters of liquid products that
contain organic HAP with a rack weighted average vapor pressure greater
than or equal to 10.3 kPa are required to equip each transfer rack with
a vapor collection system and control device to reduce total organic
HAP emissions by 98 percent by weight or to an exit concentration of 20
ppmv, whichever is less stringent. The HON also allows multiple other
options to control emissions from applicable transfer racks, including:
use of a flare, or collecting emissions for use in the process, a fuel
gas system, or a vapor balance system. However, as previously
mentioned, the HON excludes transfer racks with an operating pressure
greater than 204.9 kPa from these requirements. While we recognize that
these high operating pressure transfer racks are likely being
controlled by owners and operators, the HON does not currently require
them to be controlled on the presupposition that transfer racks with an
operating pressure greater than 204.9 kPa do not leak emissions to the
atmosphere. We consider the lack of control requirements for transfer
racks with an operating pressure greater than 204.9 kPa to be a gap in
the current HON. As such, we are proposing to remove the 204.9 kPa
operating pressure exemption from the definition of transfer operations
at 40 CFR 63.101 on the premise that, just like pressure vessels (as
discussed in section III.D.6 of this preamble), these high operating
pressure transfer racks can have

emissions to the atmosphere. Considering this, owners and operators
would be required to equip each transfer rack with an operating
pressure greater than 204.9 kPa with a vapor collection system and
control device to reduce total organic HAP emissions by 98 percent by
weight or to an exit concentration of 20 parts per million by volume,
whichever is less stringent. These requirements are consistent with CAA
section 112(d) controls and reflect the MACT floor, and we did not
identify any additional options beyond this (i.e., beyond-the-floor
options) for controlling emissions from these transfer racks.
    We anticipate that the proposed removal of the 204.9 kPa operating
pressure exemption from the definition of transfer operations would not
impose a cost increase because we believe that owners and operators are
already controlling emissions from transfer racks with an operating
pressure greater than 204.9 kPa. For example, as discussed in an EPA
published document regarding sources of EtO,\145\ EtO is normally
shipped in 38,000 and 76,000 liter (10,000 and 20,000 gallon) railroad
tank cars, which are normally loaded directly from plant storage
vessels. The transfer generally occurs at about 350 kPa. At most
facilities, displaced vapors from the filling of tank cars and storage
vessels are either recycled to the process or scrubbed prior to
incineration or flaring. When the vapors are scrubbed, the liquid
effluent from the scrubber is routed to the desorber for EtO recovery.
Emissions of EtO from storage and loading are assumed to be nearly zero
if either control approach is used. We solicit comment on the proposed
removal of the 204.9 kPa operating pressure exemption from the
definition of transfer operations and whether our assumption that these
types of transfer racks are already being controlled is reasonable.
---------------------------------------------------------------------------

    \145\ EPA. Locating And Estimating Air Emissions From Sources Of
Ethylene Oxide. September 1986. EPA-450/4-84-007L.
---------------------------------------------------------------------------

9. Heat Exchange Systems (for P&R II)
    P&R II currently does not regulate HAP emissions from heat exchange
systems. However, as previously discussed in sections III.B.2.a.iii and
III.C.1 of this preamble, the internal tubing material of a heat
exchanger can corrode or crack, allowing some process fluids to mix or
become entrained with the cooling water. Pollutants in the process
fluids may subsequently be released from the cooling water into the
atmosphere when the water is exposed to air (e.g., in a cooling tower
for closed-loop systems or trenches/ponds in a once-through system).
For this reason, we are proposing under CAA section 112(d)(2) and (3)
to include in P&R II the same LDAR program for heat exchange systems as
in the HON and P&R I, and we are proposing the same changes to this
LDAR program for P&R II that we are proposing in this action for the
HON and P&R I (see section III.C.1 of this preamble). Specifically, we
are proposing at 40 CFR 63.522 to revise the definition of ``affected
source'' to include heat exchange systems; and we are proposing the
same definition of ``heat exchange systems'' for P&R II that is already
used in the HON and P&R I to mean ``any cooling tower system or once-
through cooling water system (e.g., river or pond water). A heat
exchange system can include more than one heat exchanger and can
include an entire recirculating or once-through cooling system.''
    We reviewed publicly available air permits for the five facilities
subject to either the BLR or WSR standards in P&R II and found that
some of these facilities do have heat exchange systems. In reviewing
air permits, three of the five facilities subject to P&R II are
collocated with HON sources. Furthermore, we also anticipate that the
heat exchange systems used at these sources are small (<10,000 gallons
per minute) and would likely be sent to large, integrated cooling
towers subject to other NESHAP, like the HON, that are already
conducting water sampling at the cooling tower for leaks. Additionally,
we expect that most water used by heat exchange systems in P&R II
processes are likely from water jacketed reactors that either have
large pressure differentials (i.e., >35 kPa) between the cooling water
side and process side or have intervening cooling fluids between the
process and cooling water such that leaks of HAP would not occur in
heat exchange systems that would lead to air emissions. Given this, we
assumed that adding requirements for heat exchange systems would
already be accounted for in the HON or that heat exchange systems would
not be required to conduct such monitoring at P&R II sources because
they meet criteria that exempt heat exchange systems with no potential
for air emissions from the LDAR requirements. Thus, conducting an LDAR
program consistent with what is in the HON constitutes what the best
performers are doing and is the MACT floor level of control for P&R II
facilities. We note that even if a P&R II facility were to incur a cost
to implement a LDAR program for a heat exchange system, we would expect
this cost to be small (i.e., $4,300 in total capital investment and
$4,500/yr in total annualized cost) per the costs for a single heat
exchange system conducting El Paso monitoring and that this work
practice standard would be cost-effective for P&R II sources as a
beyond-the-floor control option. Thus, we are proposing that P&R II
sources comply with the same standard as we are proposing for HON and
P&R I heat exchange systems as part of our technology review (see
section III.C.1 of this preamble). For further information, see the
document titled Clean Air Act Section 112(d)(6) Technology Review for
Heat Exchange Systems Located in the SOCMI Source Category that are
Associated with Processes Subject to HON and for Heat Exchange Systems
that are Associated with Processes Subject to Group I Polymers and
Resins NESHAP; and Control Option Impacts for Heat Exchange Systems
that are Associated with Processes Subject to Group II Polymers and
Resins NESHAP, which is available in the docket for this rulemaking.
    We are proposing at 40 CFR 63.523(d) (for BLR manufacturers) and 40
CFR 63.524(c) (for WSR manufacturers) that owners and operators of each
affected source comply with the requirements of 40 CFR 63.104 for heat
exchange systems, except we are proposing to require quarterly
monitoring for existing and new heat exchange systems (after an initial
6 months of monthly monitoring) using the Modified El Paso Method and a
leak definition of 6.2 ppmv of total strippable hydrocarbon
concentration (as methane) in the stripping gas. We are also proposing
at 40 CFR 63.104(j)(3) a delay of repair action level of total
strippable hydrocarbon concentration (as methane) in the stripping gas
of 62 ppmv, that if exceeded during leak monitoring, would require
immediate repair (i.e., the leak found cannot be put on delay of repair
and would be required to be repaired within 30 days of the monitoring
event). This would apply to both monitoring heat exchange systems and
individual heat exchangers by replacing the use of any 40 CFR part 136
water sampling method with the Modified El Paso Method and removing the
option that allows for use of a surrogate indicator of leaks. We are
also proposing at 40 CFR 63.104(h) and (i) re-monitoring at the
monitoring location where a leak is identified to ensure that any leaks
found are fixed. Finally, we are proposing that none of these proposed
requirements would apply to heat exchange systems that have a maximum
cooling water flow rate of 10 gallons per minute or less. We solicit

comment on the proposed standards for heat exchange systems for P&R II.
10. WSR Sources and Equipment Leaks (for P&R II)
    P&R II currently contains an alternative standard for WSR sources
that establishes a regulatory gap in the rule at 40 CFR 63.524(a) and
(b). The alternative standard allows owners and operators of WSR
sources to choose between complying with a production-based emission
limit for process vents, storage tanks, and wastewater systems, or the
requirements of NESHAP subpart H to control emissions from equipment
leaks. In other words, owners and operators of WSR sources are
currently not required to control emissions from all of their P&R II
emission sources.\146\ In the original proposed rulemaking, the EPA
stated that: ``Because no existing facility in the WSR source category
controls equipment leak emissions, the MACT floor for the equipment
leaks portion of the source represents an uncontrolled situation.''
\147\ Instead, the EPA promulgated the alternative standard for WSR
sources and said ``an alternative standard was specified that allows
facilities to implement the requirements of subpart H to control
emissions from equipment leaks. The alternative standard is much more
cost effective, and will result in a greater overall HAP emission
reduction. However, the alternative standard is not being required
because the cost was considered to be too high to justify requiring
more control than that achieved at the MACT floor. Section 112(d) of
the Clean Air Act requires standards to be set at a level no less
stringent than the MACT floor but requires consideration of the cost of
achieving further reductions before requiring reductions beyond the
MACT floor.'' \148\ We are proposing to address this regulatory gap by
requiring owners and operators of existing, new, or reconstructed
affected WSR sources to comply with both the equipment leak standards
in the HON and the HAP emissions limitation for process vents, storage
tanks, and wastewater systems (see proposed 40 CFR 63.524(a)(3) and
(b)(3)). We are also proposing to remove several introductory phrases
in P&R II that currently indicate the alternative standard is optional;
and instead, we are proposing to replace these phrases with text that
indicate the alternative standard is no longer optional, but required
(see proposed 40 CFR 63.525(e) through (i), 40 CFR 63.526(b) and (d),
and 40 CFR 63.527(b) through (d)). As previously mentioned, the EPA
determined that no WSR source was originally complying with the
requirements of NESHAP subpart H; instead, these WSR sources were
originally complying with the production-based emission limit for
process vents, storage tanks, and wastewater systems. However, a review
of the publicly available permits for the two WSR sources indicates
that they are currently complying with the equipment leak requirements
of the HON; thus, we believe the requirements are consistent with CAA
section 112(d) controls, reflect the MACT floor, and there are no
additional costs from this change. We also did not identify any
additional options beyond those identified above (i.e., beyond-the-
floor options) for reducing emissions from WSR sources. We solicit
comment on our proposal to require owners and operators of existing,
new, or reconstructed affected WSR sources to comply with both the
equipment leak standards in the HON and the HAP emissions limitation
for process vents, storage tanks, and wastewater systems, and whether
our assumption that the affected WSR sources are already complying with
both standards is reasonable.
---------------------------------------------------------------------------

    \146\ This alternative standard is not an option for BLR
sources; therefore, there is no regulatory gap in P&R II for BLR
sources. Instead, owners and operators of BLR sources are subject to
both a production-based emission limit for process vents, storage
tanks, and wastewater systems, and the requirements of NESHAP
subpart H to control emissions from equipment leaks (see 40 CFR
63.523).
    \147\ See 59 FR 25387, May 16, 1994.
    \148\ See 60 FR 12670, March 8, 1995.
---------------------------------------------------------------------------

    In addition, the definition of equipment leaks in P&R II at 40 CFR
63.522 excludes ``valves'' in the list of components; therefore, P&R II
currently does not regulate HAP emissions from leaking valves. We
believe this is a typographical error in P&R II and the EPA has always
intended to include valves as part of the equipment leaks LDAR program
requirements in P&R II. We note that in the original P&R II proposal
(see 59 FR 25387, May 16, 1994), the EPA referred to equipment leak
emission points using a phrase implying valve inclusivity (i.e., ``such
as pumps and valves''). Additionally, the BLR and WSR model plants used
to assess impacts of implementing the LDAR requirements in P&R II
included valve component counts; \149\ and no adverse comment was
received on this topic between proposal and final rulemaking for P&R
II. As previously mentioned, emissions of HAP from equipment leaks
occur in the form of gases or liquids that escape to the atmosphere
through many types of connection points (including valves). For this
reason, we are proposing under CAA section 112(d)(2) and (3) to include
valves in the definition of ``equipment leaks'' at 40 CFR 63.522 such
that owners and operators of an existing, new, or reconstructed
affected BLR or WSR source would be required to comply with the same
LDAR program that already exists in the HON and P&R I for valves that
contain or contact material that is 5 percent by weight or more of
organic HAP, operate 300 hours per year or more, and are not in vacuum
service. Specifically, our proposal would require owners or operators
to meet the control requirements for valves in NESHAP subpart H (see
section III.C.6.a of this preamble for a more detailed description of
the MACT standard for equipment leaks). A review of the publicly
available permits for P&R II sources indicates that P&R II facilities
are already complying with the equipment leak requirements of the HON
(which include LDAR requirements for valves), so we believe there are
no additional cost or emissions reduction from this proposed
typographical correction. We solicit comment on the proposed revisions
for equipment leaks from WSR sources in P&R II.
---------------------------------------------------------------------------

    \149\ See Appendix G of the document titled Hazardous Air
Pollutants From Epoxy Resins And Non-nylon Polyamide Resins
Production (Docket ID A-92-37, Item II-A-008).
---------------------------------------------------------------------------

E. What other actions are we proposing, and what is the rationale for
those actions?

    In addition to the proposed actions on the CAA 111(b)(1)(B) and
112(d)(6) reviews discussed in section III.A of this preamble, we are
proposing to remove exemptions in the HON, P&R I, and P&R II from the
requirement to comply during periods of SSM; similarly, we are
proposing standards in NSPS subparts VVb, IIIa, NNNa, and RRRa that
apply at all times. We are also proposing to remove the affirmative
defense provisions from P&R I that were adopted in 2011. In addition,
we are proposing changes to the HON, P&R I, and P&R II recordkeeping
and reporting requirements to require the use of electronic reporting
of performance test reports and periodic reports; and we are proposing
similar standards in NSPS subparts VVb, IIIa, NNNa, and RRRa. We are
also proposing in the HON, P&R I, and P&R II to correct section
reference errors and make other minor editorial revisions. Finally, in
response to a petition for reconsideration, we are proposing to amend
NSPS subpart VVa; and although not part of the petition for
reconsideration, we are also proposing to clarify (in NSPS subpart VVa)
the

calibration drift assessment and correct the incorporations by
reference. Our rationale and proposed changes related to all of these
issues are discussed below.
1. SSM
    In its 2008 decision in Sierra Club v. EPA, 551 F.3d 1019 (D.C.
Cir. 2008), the United States Court of Appeals for the District of
Columbia Circuit (the court) vacated portions of two provisions in the
EPA's CAA section 112 regulations governing the emissions of HAP during
periods of SSM. Specifically, the court vacated the SSM exemption
contained in 40 CFR 63.6(f)(1) and 40 CFR 63.6(h)(1), holding that
under section 302(k) of the CAA, emissions standards or limitations
must be continuous in nature and that the SSM exemption violates the
CAA's requirement that some section 112 standards apply continuously.
With the issuance of the mandate in Sierra Club v. EPA, the exemption
language in 63.6(f)(1) and (h)(1) are null and void and any cross
reference to those provisions have no effect.
    In March 2021, the EPA issued a rule \150\ to reflect the court
vacatur that revised the Part 63 General Provisions to remove the SSM
exemptions at 40 CFR 63.6(f)(1) and (h)(1). In this action, we are
proposing to eliminate references in the HON, P&R I, and P&R II to
these SSM exemptions in the General Provisions that are null and void
and are no longer printed in the CFR, remove any additional SSM
exemptions or references to SSM exemptions in the HON, P&R I, and P&R
II, and remove any cross-references in the HON, P&R I, and P&R II to
provisions in 40 CFR part 63 (General Provisions) that are unnecessary,
inappropriate or redundant in the absence of the SSM exemption.\151\
See section III.E.1.a of this preamble for our proposed amendments to
the HON, P&R I, and P&R II related to the SSM exemptions. The EPA has
attempted to ensure that the general provisions we are proposing to
override are inappropriate, unnecessary, or redundant in the absence of
the SSM exemption. We specifically seek comment on whether we have
successfully done so.
---------------------------------------------------------------------------

    \150\ U.S. EPA, Court Vacatur of Exemption From Emission
Standards During Periods of Startup, Shutdown, and Malfunction. (86
FR 13819, March 11, 2021).
    \151\ We note that on April 21, 2011 (see 77 FR 22566), the EPA
finalized amendments to eliminate the SSM exemption in P&R I;
however, for consistency with the SSM related amendments that we are
proposing for the HON and P&R II, we are also proposing (as detailed
in this section of this preamble) additional amendments to P&R I
related to the SSM exemption that were not addressed in the April
21, 2011, P&R I rule.
---------------------------------------------------------------------------

    Additionally, the EPA has determined the reasoning in the court's
decision in Sierra Club applies equally to CAA section 111 because the
definition of emission or standard in CAA section 302(k), and the
embedded requirement for continuous standards, also applies to the
NSPS.\152\ Therefore, we are proposing standards in NSPS subparts VVb,
IIIa, NNNa, and RRRa that apply at all times, and more specifically
during periods of SSM, to match the proposed revised SSM provisions in
the HON, P&R I, and P&R II. The NSPS general provisions in 40 CFR
60.8(c) currently exempt non-opacity emission standards during periods
of SSM. We are proposing in NSPS subparts VVb, IIIa, NNNa, and RRRa
specific requirements \153\ that override the general provisions for
SSM. See section E.1.b of this preamble for our proposed standards
related to the SSM exemptions for NSPS subparts VVb, IIIa, NNNa, and
RRRa.
---------------------------------------------------------------------------

    \152\ See, e.g., 88 FR 11556 (Feb. 23, 2023) (removing SSM
exemptions from NSPS for lead acid battery manufacturing plants); 87
FR 73708 (Dec. 1, 2022) (proposing to remove SSM exemptions from
NSPS for secondary lead smelters); 77 FR 49490 (Aug. 16, 2012)
(removing SSM exemptions from NSPS for oil and natural gas sector).
    \153\ See proposed 40 CFR 60.482-1b, 40 CFR 60.612a, 40 CFR
60.662a, and 40 CFR 60.702a, respectively.
---------------------------------------------------------------------------

a. Proposed Elimination of the SSM Exemption in the HON, P&R I, and P&R
II
    We are proposing the elimination of the vacated exemption provision
and several revisions to Table 3 to subpart F of part 63 (the General
Provisions Applicability Table to subparts F, G, and H of 40 CFR part
63, hereafter referred to as the ``General Provisions table to HON''),
Table 1 to subpart U of part 63 (the General Provisions Applicability
Table to subpart U of 40 CFR part 63, hereafter referred to as the
``General Provisions table to P&R I''), and Table 1 to subpart W of
part 63 (the General Provisions Applicability Table to subpart W of 40
CFR part 63, hereafter referred to as the ``General Provisions table to
P&R II'') as is explained in more detail below. For example, we are
proposing to eliminate the incorporation of the General Provisions'
requirement that the source develop an SSM plan. We also are proposing
to eliminate and revise certain recordkeeping and reporting
requirements related to the SSM exemption. The EPA has attempted to
ensure that the provisions we are proposing to eliminate are
inappropriate, unnecessary, or redundant in the absence of the SSM
exemption.
    For the HON and P&R II, we are proposing (as already required in
P&R I at 40 CFR 63.480(j)) that emissions from startup and shutdown
activities be included when determining if all the standards are being
met. As currently proposed in 40 CFR 63.102(e) and 40 CFR.525(j),
compliance with the emission limitations (including operating limits)
in the HON and P&R II is required ``at all times.'' We solicit comment
on whether owners and operators of affected sources subject to the HON
or P&R II will be able to comply with the standards during these times.
We also note that we are proposing standards for maintenance activities
that occur during periods of startup and shutdown (see section III.D.4
of this preamble). Emission reductions for storage vessel, process
vent, transfer rack, and wastewater operations (as well as other
emission sources) are typically achieved by routing vapors to an APCD
such as a flare, thermal oxidizer, or carbon adsorber. It is common
practice in this source category to start an APCD prior to startup of
the emissions source it is controlling, so the APCD would be operating
before emissions are routed to it. We expect APCDs would be operating
during startup and shutdown events in a manner consistent with normal
operating periods, and that these APCDs will be operated to maintain
and meet the monitoring parameter operating limits set during the
performance test.
    Periods of startup, normal operations, and shutdown are all
predictable and routine aspects of a source's operations. Malfunctions,
in contrast, are neither predictable nor routine. Instead, they are, by
definition, sudden, infrequent, and not reasonably preventable failures
of emissions control, process, or monitoring equipment. (40 CFR 60.2
and 40 CFR 63.2) (definition of ``malfunction''). The EPA interprets
CAA section 112 as not requiring emissions that occur during periods of
malfunction to be factored into development of CAA section 112
standards and this reading has been upheld as reasonable by the D.C.
Circuit in U.S. Sugar Corp. v. EPA, 830 F.3d 579, 606-610 (2016).
Therefore, the standards that apply during normal operation apply
during periods of malfunction.
    Although no statutory language compels the EPA to set standards for
malfunctions, the EPA has the discretion to do so where feasible. For
example, in the Petroleum Refinery Sector RTR, the EMACT standards, and

the MON, the EPA established a work practice standard for unique types
of malfunction that result in releases from PRDs or emergency flaring
events because the EPA had information to determine that such work
practices reflected the level of control that applies to the best
performers (see 80 FR 75178, December 1, 2015, 85 FR 40386, July 6,
2020, and 85 FR 49084, August 12, 2020, respectively). The EPA will
consider whether circumstances warrant setting standards for a
particular type of malfunction in the SOCMI, P&R I, and P&R II source
categories, and, if so, whether the EPA has sufficient information to
identify the relevant best performing sources and establish a standard
for such malfunctions. We also encourage commenters to provide any such
information. These are discussed further in section III.D.1 and III.D.2
of this preamble.
    We are also proposing the following revisions to the General
Provisions table to HON, the General Provisions table to P&R I, and the
General Provisions table to P&R II as detailed below.
i. General Duty
    We are proposing to revise the General Provisions table to the HON
entry for 40 CFR 63.6(e) by adding a footnote to the ``yes'' entry in
column 2 to clarify that the row for the ``63.6(e)'' entry would no
longer be applicable beginning 3 years after publication of the final
rule in the Federal Register because the General Provisions table to
HON already contains other entries that breakdown the specific
paragraphs of 63.6(e) that are applicable to the HON. Some of the
language in section 63.6(e) is no longer necessary or appropriate in
light of the elimination of the SSM exemption. Section 63.6(e)(1)(i)
describes the general duty to minimize emissions and section 63.6(e)(3)
describes requirements for an SSM plan. We are proposing instead to add
general duty regulatory text at 40 CFR 63.102(f) (for HON) and 40 CFR
63.525(k) (for P&R II) that reflects the general duty to minimize
emissions while eliminating the reference to periods covered by an SSM
exemption. The current language in 40 CFR 63.6(e)(1)(i) characterizes
what the general duty entails during periods of SSM. With the
elimination of the SSM exemption, there is no need to differentiate
between normal operations, startup and shutdown, and malfunction events
in describing the general duty. We are also proposing to revise the
General Provisions table to P&R II entry for 40 CFR 63.6(e)(1)(i) by
adding a separate row for 40 CFR 63.6(e)(1)(i) and changing the ``yes''
in columns 2, 3, and 4 to a ``no'' in which 40 CFR 63.6(e)(1)(i) would
no longer be applicable beginning 3 years after publication of the
final rule in the Federal Register. Section 63.6(e)(1)(i) imposes
requirements that are not necessary with the elimination of the SSM
exemption or are redundant with the general duty requirement being
added at 40 CFR 63.102(f) and 40 CFR 63.525(k). Therefore, the language
the EPA is proposing for 40 CFR 63.102(f) and 40 CFR 63.525(k) does not
include the language from 40 CFR 63.6(e)(1). We note that the EPA
already added a similar general duty provision to P&R I at 40 CFR
63.483(a) (see 77 FR 22566, April 21, 2011); however, we are proposing
to correct a referencing error in the General Provisions table to P&R I
entry for 40 CFR 63.6(e)(1)(i) by changing ``Sec.  63.483(a)(1)'' to
``Sec.  63.483(a)''. We are also proposing revisions at 40 CFR
63.483(a) to be consistent with the general duty requirement we are
proposing to add to 40 CFR 63.102(f) and 40 CFR 63.525(k).We are also
proposing to revise the General Provisions table to HON entry for 40
CFR 63.6(e)(1)(ii) by changing the ``yes'' in column 2 to a ``no'' in
which 40 CFR 63.6(e)(1)(ii) would no longer be applicable beginning 3
years after publication of the final rule in the Federal Register. We
are proposing similar revisions for the General Provisions table to P&R
II by adding a separate row for 40 CFR 63.6(e)(1)(ii) and changing the
``yes'' in columns 2, 3, and 4 to a ``no'' in which 40 CFR
63.6(e)(1)(ii) would no longer be applicable beginning 3 years after
publication of the final rule in the Federal Register. We note that the
EPA already made a similar revision to the General Provisions table to
P&R I (see 77 FR 22566, April 21, 2011).
ii. SSM Plan
    As noted in the previous paragraph, the proposed revisions to the
General Provisions table to the HON and the General Provisions table to
P&R II for 40 CFR 63.6(e) will also remove provisions that require an
SSM plan. We are proposing to revise the General Provisions table to
HON entries for 40 CFR 63.6(e)(3)(i), 63.6(e)(3)(i)(B), (C),
63.6(e)(3)(ii) and (vi) through (ix) by changing the ``yes'' in column
2 to a ``no'' in which these provisions would no longer be applicable
beginning 3 years after publication of the final rule in the Federal
Register. We are proposing similar revisions for the General Provisions
table to P&R II by adding a separate row for 40 CFR 63.6(e)(3) and
changing the ``yes'' in columns 2, 3, and 4 to a ``no'' in which 40 CFR
63.6(e)(3) would no longer be applicable beginning 3 years after
publication of the final rule in the Federal Register. We note that the
EPA already made a similar revision to the General Provisions table to
P&R I (see 77 FR 22566, April 21, 2011). Generally, the paragraphs
under 40 CFR 63.6(e)(3) require development of an SSM plan and specify
SSM recordkeeping and reporting requirements related to the SSM plan.
As noted, the EPA is proposing to remove the SSM exemptions. Therefore,
affected units are subject to an emission standard during such events.
The applicability of a standard during such events will ensure that
sources have ample incentive to plan for and achieve compliance and
thus the SSM plan requirements are no longer necessary.
iii. Compliance With Standards
    We are proposing to clarify the comment in the General Provisions
table to HON entry for 40 CFR 63.6(f)(1) to include a reference to the
new proposed general duty requirements at 40 CFR 63.102(e). We are also
proposing to add a separate row for 40 CFR 63.7(a)(4) to the General
Provisions tables to the HON, P&R I, and P&R II to make 40 CFR
63.7(a)(4) applicable to each of these NESHAP for when an owner or
operator intends to assert a claim of force majeure.
iv. Performance Testing
    We are proposing to revise the General Provisions table to HON
entry for 40 CFR 63.7(e)(1) by changing the ``yes'' in column 2 to a
``no'' in which 40 CFR 63.7(e)(1) would no longer be applicable
beginning 3 years after publication of the final rule in the Federal
Register. Section 63.7(e)(1) describes performance testing
requirements. We are proposing a similar revision to the General
Provisions table to P&R II entry for 40 CFR 63.7(e)(1) by changing the
``yes'' in columns 2, 3, and 4 to a ``no'' in which 40 CFR 63.7(e)(1)
would no longer be applicable beginning 3 years after publication of
the final rule in the Federal Register. We note that the EPA already
made a similar revision to the General Provisions table to P&R I (see
77 FR 22566, April 21, 2011). The EPA is instead proposing to add a
performance testing requirement at 40 CFR 63.103(b)(3)(ii) (for HON),
40 CFR 63.504(a)(1)(iii) (for P&R I), and 40 CFR 63.525(l) (for P&R
II). The performance testing requirements we are proposing differ from
the General Provisions performance testing provisions in several
respects. The regulatory text does not include the language in 40 CFR
63.7(e)(1) that restated the SSM

exemption and language that precluded startup and shutdown periods from
being considered ``representative'' for purposes of performance
testing. The proposed performance testing provisions will exclude
periods of startup or shutdown as representative conditions for
conducting performance testing. As in 40 CFR 63.7(e)(1), performance
tests conducted under this subpart should not be conducted during
malfunctions because conditions during malfunctions are often not
representative of normal operating conditions. The EPA is proposing to
add language that requires the owner or operator to record the process
information that is necessary to document operating conditions during
the test and include in such record an explanation to support that such
conditions represent normal operation. Section 63.7(e)(1) requires that
the owner or operator make such records ``as may be necessary to
determine the condition of the performance test'' available to the
Administrator upon request but does not specifically require the
information to be recorded. The regulatory text the EPA is proposing to
add to this provision builds on that requirement and makes explicit the
requirement to record the information.
v. Monitoring
    We are proposing to revise the General Provisions tables to the HON
and P&R I entries for 40 CFR 63.8(c)(1)(i) and (iii) by changing the
``yes'' in column 2 to a ``no'' in which 40 CFR 63.8(c)(1)(i) and (iii)
would no longer be applicable beginning 3 years after publication of
the final rule in the Federal Register. We are proposing similar
revisions for the General Provisions table to P&R II entries for 40 CFR
63.8(c)(1)(i) and (iii) by changing the ``yes'' in columns 2, 3, and 4
to a ``no'' in which 40 CFR 63.8(c)(1)(i) and (iii) would no longer be
applicable beginning 3 years after publication of the final rule in the
Federal Register. The cross-references to the general duty and SSM plan
requirements in those subparagraphs are not necessary in light of other
requirements of 40 CFR 63.8 that require good air pollution control
practices (40 CFR 63.8(c)(1)).
vi. Reporting
    We are proposing to revise the General Provisions table to the HON
entry for 40 CFR 63.10(d)(5) by changing the ``yes'' in column 2 to a
``no'' in which 40 CFR 63.10(d)(5) would no longer be applicable
beginning 3 years after publication of the final rule in the Federal
Register. We are proposing similar revisions for the General Provisions
table to P&R II entry for 40 CFR 63.10(d)(5) by changing the ``yes'' in
columns 2, 3, and 4 to a ``no'' in which 40 CFR 63.10(d)(5) would no
longer be applicable beginning 3 years after publication of the final
rule in the Federal Register. We note that the EPA already made a
similar revision to the General Provisions table to P&R I (see 77 FR
22566, April 21, 2011). Section 63.10(d)(5) describes the reporting
requirements for SSM. To replace the General Provisions reporting
requirement, the EPA is proposing to add reporting requirements to 40
CFR 63.152(c)(2)(ii)(F) (for HON), 40 CFR 63.506(e)(6)(iii)(C) (for P&R
I), and 40 CFR 63.528(a)(4) (for P&R II). The replacement language
differs from the General Provisions requirement in that it eliminates
periodic SSM reports as a stand-alone report. We are proposing language
that requires sources that fail to meet an applicable standard at any
time to report the information concerning such events in the periodic
report already required under the HON, P&R I, and P&R II. We are
proposing that the report must contain the cause of such events
(including unknown cause, if applicable), a list of the affected source
or equipment, an estimate of the quantity of each regulated pollutant
emitted over any emission limit, and a description of the method used
to estimate the emissions. Examples of such methods would include
product-loss calculations, mass balance calculations, measurements when
available, or engineering judgment based on known process parameters.
The EPA is proposing this requirement to ensure that there is adequate
information to determine compliance, to allow the EPA to determine the
severity of the failure to meet an applicable standard, and to provide
data that may document how the source met the general duty to minimize
emissions during a failure to meet an applicable standard.
    We will no longer require owners or operators to determine whether
actions taken to correct a malfunction are consistent with an SSM plan,
because plans would no longer be required. The proposed amendments at
63.10(d)(5), therefore, eliminate the cross-reference to 40 CFR
63.10(d)(5)(i) that contains the description of the previously required
SSM report format and submittal schedule from this section. These
specifications are no longer necessary because the events will be
reported in otherwise required reports with similar format and
submittal requirements.
    The proposed amendments at 63.10(d)(5) will also eliminate the
cross-reference to 40 CFR 63.10(d)(5)(ii). Section 63.10(d)(5)(ii)
describes an immediate report for startups, shutdown, and malfunctions
when a source failed to meet an applicable standard but did not follow
the SSM plan. We will no longer require owners or operators to report
when actions taken during a startup, shutdown, or malfunction were not
consistent with an SSM plan, because plans would no longer be required.
b. Proposal of NSPS Subparts VVb, IIIa, NNNa, and RRRa Without SSM
Exemptions
    We are proposing standards in the NSPS subparts VVb, IIIa, NNNa,
and RRRa that apply at all times. For NSPS VVb, we are proposing that
the work practice standards will apply at all times, including during
SSM. For NSPS subparts IIIa, NNNa, and RRRa, these standards include
the performance standards when the affected facilities are operational
and work practice standards that will apply during periods of startup
and shutdown (including when maintenance and inspection activities are
being conducted). The NSPS general provisions in 40 CFR 60.8(c) contain
an exemption from non-opacity standards. Therefore, we are also
proposing in NSPS subparts VVb, IIIa, NNNa, and RRRa specific
requirements at 40 CFR 60.482-1b, 40 CFR 60.612a, 40 CFR 60.662a, and
40 CFR 60.702a, respectively that override the general provisions for
SSM. Accordingly, our proposed NSPS subparts VVb, IIIa, NNNa, and RRRa
would include standards that apply at all times, including during
periods of startup and shutdown.
    Periods of startup, normal operations, and shutdown are all
predictable and routine aspects of a source's operations. Malfunctions,
in contrast, are neither predictable nor routine. Instead they are, by
definition, sudden, infrequent, and not reasonably preventable failures
of emissions control, process, or monitoring equipment. (40 CFR 60.2).
The EPA interprets CAA section 111 as not requiring emissions that
occur during periods of malfunction to be factored into development of
CAA section 111 standards. Nothing in CAA section 111 or in case law
requires that the EPA consider malfunctions when determining what
standards of performance reflect the degree of emission limitation
``achievable through the application of the best system of emission
reduction'' that the EPA determines is adequately demonstrated. While
the EPA accounts for variability in setting emissions standards, the
EPA is not required to treat a malfunction in

the same manner as the type of variation in performance that occurs
during routine operations of a source. A malfunction is a failure of
the source to perform in a ``normal or usual manner'' (40 CFR 60.2),
and no statutory language compels the EPA to consider such events in
setting section 111 standards of performance. The EPA's approach to
malfunctions when interpreting analogous language under CAA section 112
has been upheld as reasonable by the D.C. Circuit in U.S. Sugar Corp.
v. EPA, 830 F.3d 579, 606-610 (D.C. Cir. 2016) (affirming as reasonable
the EPA's approach to setting ``achievable'' standards under section
112 as measured by the ``best controlled similar source'' without
considering malfunctions, instead accounting for them in its
enforcement discretion).
    Also, as previously discussed, although no statutory language
compels the EPA to set standards for malfunctions, the EPA has the
discretion to do so where feasible. The EPA is proposing to establish
work practice standards for unique types of malfunction that result in
releases from emergency flaring events because the EPA had information
to determine that such work practices reflected the level of control
that applies to the BSER. The EPA will consider whether circumstances
warrant setting standards for a particular type of malfunction in the
SOCMI NSPS rules, and, if so, whether the EPA has sufficient
information to identify the relevant best performing sources and
establish a standard for such malfunctions. We also encourage
commenters to provide any such information. These are discussed further
in sections III.D.1, III.C.3.b, and III.C.6.b of this preamble.
2. Affirmative Defense (Related to P&R I)
    As part of one of the P&R I RTR rulemakings (see 77 FR 22566, April
21, 2011), the EPA included the ability to assert an affirmative
defense to civil penalties for violations caused by malfunctions (see
40 CFR 63.480(j)(4)) in an effort to create a system that incorporated
some flexibility, recognizing that there is a tension, inherent in many
types of air regulation, to ensure adequate compliance while
simultaneously recognizing that despite the most diligent of efforts,
emission standards may be violated under circumstances entirely beyond
the control of the source.\154\ Although the EPA recognized that its
case-by-case enforcement discretion provides sufficient flexibility in
these circumstances, it included the affirmative defense provision to
provide a more formalized approach and more regulatory clarity. See
Weyerhaeuser Co. v. Costle, 590 F.2d 1011, 1057-58 (D.C. Cir. 1978)
(holding that an informal case-by-case enforcement discretion approach
is adequate); but see Marathon Oil Co. v. EPA, 564 F.2d 1253, 1272-73
(9th Cir. 1977) (requiring a more formalized approach to consideration
of ``upsets beyond the control of the permit holder.''). Under the
EPA's regulatory affirmative defense provisions, if a source could
demonstrate in a judicial or administrative proceeding that it had met
the requirements of the affirmative defense in the regulation, civil
penalties would not be assessed. However, the court vacated the
affirmative defense in one of the EPA's CAA section 112 regulations.
NRDC v. EPA, 749 F.3d 1055 (D.C. Cir., 2014) (vacating affirmative
defense provisions in the CAA section 112 rule establishing emission
standards for Portland cement kilns). The court found that the EPA
lacked authority to establish an affirmative defense for private civil
suits and held that under the CAA, the authority to determine civil
penalty amounts in such cases lies exclusively with the courts, not the
EPA. Specifically, the court found: ``As the language of the statute
makes clear, the courts determine, on a case-by-case basis, whether
civil penalties are `appropriate.''' See NRDC, 749 F.3d at 1063
(``[U]nder this statute, deciding whether penalties are `appropriate'
in a given private civil suit is a job for the courts, not
EPA.'').\155\ In light of NRDC, the EPA is proposing to remove all of
the regulatory affirmative defense provisions from P&R I at 40 CFR
480(j)(4) in its entirety and all other rule text that references these
provisions (i.e., the reference to ``Sec.  63.480(j)(4)'' in 40 CFR
63.506(b)(1)(i)(A) and (b)(1)(i)(B)). As explained above, if a source
is unable to comply with emissions standards as a result of a
malfunction, the EPA may use its case-by-case enforcement discretion to
provide flexibility, as appropriate. Further, as the court recognized,
in an EPA or citizen enforcement action, the court has the discretion
to consider any defense raised and determine whether penalties are
appropriate. Cf. NRDC, 749 F.3d at 1064 (arguments that violation was
caused by unavoidable technology failure can be made to the courts in
future civil cases when the issue arises). The same is true for the
presiding officer in EPA administrative enforcement actions.\156\
---------------------------------------------------------------------------

    \154\ We note that the HON and P&R II do not include affirmative
defense rule text.
    \155\ The court's reasoning in NRDC focuses on civil judicial
actions. The court noted that ``EPA's ability to determine whether
penalties should be assessed for CAA violations extends only to
administrative penalties, not to civil penalties imposed by a
court.'' Id.
    \156\ Although the NRDC case does not address the EPA's
authority to establish an affirmative defense to penalties that are
available in administrative enforcement actions, we are not
including such an affirmative defense in the proposed rule. As
explained above, such an affirmative defense is not necessary.
Moreover, assessment of penalties for violations caused by
malfunctions in administrative proceedings and judicial proceedings
should be consistent. Cf. CAA section 113(e) (requiring both the
Administrator and the court to take specified criteria into account
when assessing penalties).
---------------------------------------------------------------------------

3. Electronic Reporting
    The EPA is proposing that owners and operators of SOCMI processes
located at chemical plants submit electronic copies of required
performance test reports, flare management plans, and periodic reports
(including fenceline monitoring reports) through the EPA's Central Data
Exchange (CDX) using the Compliance and Emissions Data Reporting
Interface (CEDRI) (see proposed 40 CFR 63.108(e), 40 CFR 63.152(c) and
(h), and 40 CFR 63.182(d) and (e) (for HON), 40 CFR 63.506(e)(6), and
(i)(3) (for P&R I), and 40 CFR 63.528(a) and (d) (for P&R II), 40 CFR
60.486(l), and 60.487(a) and (g) through (i) (for NSPS subpart VV), 40
CFR 60.486a(l), and 60.487a(a) and (g) through (i) (for NSPS subpart
VVa), 40 CFR 60.486b(l), and 60.487b(a) and (g) through (i) (for NSPS
subpart VVb), 40 CFR 60.615(b), (j), (k), and (m) through (o) (for NSPS
subpart III), 40 CFR 60.615a(b), (h) through (l), and (n), and 40 CFR
619a(e) (for NSPS subpart IIIa), 40 CFR 60.665(b), (l), (m), and (q)
through (s) (for NSPS subpart NNN), 40 CFR 60.665a(b), (h), (k) through
(n), and (p), and 40 CFR 669a(e) (for NSPS subpart NNNa), 40 CFR
60.705(b), (l), (m), and (u) through (w) (for NSPS subpart RRR), and 40
CFR 60.705a(b), (k) through (o), and (v), and 40 CFR 709a(e) (for NSPS
subpart RRRa)). We note that for NSPS VV, VVa, III, NNN, and RRR, we
are only proposing to change the format of the reporting requirements
to require electronic reporting (i.e., we are not proposing any new
data elements). A description of the electronic data submission process
is provided in the document titled Electronic Reporting Requirements
for New Source Performance Standards (NSPS) and National Emission
Standards for Hazardous Air Pollutants (NESHAP) Rules, available in the
docket for this action.
    The proposed rules require that performance test results collected
using test methods that are supported by the

EPA's Electronic Reporting Tool (ERT) as listed on the ERT website
\157\ at the time of the test be submitted in the format generated
through the use of the ERT or an electronic file consistent with the
xml schema on the ERT website, and other performance test results be
submitted in portable document format (PDF) using the attachment module
of the ERT. Flare management plans would be uploaded as a PDF file.
---------------------------------------------------------------------------

    \157\ https://www.epa.gov/electronic-reporting-air-emissions/electronic-reporting-tool-ert.
---------------------------------------------------------------------------

    For periodic reports (including fenceline monitoring reports), the
proposed rules require that owners and operators use an appropriate
spreadsheet template to submit information to CEDRI. A draft version of
the proposed templates for these reports is included in the docket for
this action.\158\ The EPA specifically requests comment on the content,
layout, and overall design of the templates. For NSPS subpart VV, VVa,
III, NNN, and RRR, we are proposing owners and operators begin using
the templates one year after the final rule is published in the Federal
Register or once the reporting template for the subpart has been
available on the CEDRI website for 1 year, whichever date is later. For
NSPS subparts VVb, IIIa, NNNa, and RRRa, we are proposing owners and
operators begin using the templates 60 days after the final rule is
published in the Federal Register or once the reporting template for
the subpart has been available on the CEDRI website for 1 year,
whichever date is later. For HON, P&R I, and P&R II, we are proposing
owners and operators begin using the templates for periodic reports
other than fenceline reports three years after the final rule is
published in the Federal Register, or once the reporting template for
the subpart has been available on the CEDRI website for 1 year,
whichever date is later. Owners and operators would begin using the
templates for fenceline monitoring reports starting when the first
fenceline monitoring report is due.
---------------------------------------------------------------------------

    \158\ See Part_60_Subpart_VV_60.487(a)_Semiannual_Report.xlsx,
Part_60_Subpart_III_60.615_Semiannual_Report.xlsx,
Part_60_Subpart_NNN_60.665_Report.xlsx,
Part_60_Subpart_RRR_60.705_Report.xlsx,
Part_63_Subpart_G_63.152(c)_Periodic_Report.xlsx,
Part_63_Subpart_H_63.182(d)_Periodic_Report.xlsx,
Part_63_Subpart_H_63.182(e)_Fenceline_Quarterly_Report.xlsx,
Part_63_Subpart_U_63.506(e)(6)_Periodic_Report.xlsx, and
Part_63_Subpart_W_63.528(a)_Periodic_Report.xlsx, available in the
docket for this action.
---------------------------------------------------------------------------

    Additionally, the EPA has identified two broad circumstances in
which electronic reporting extensions may be provided. These
circumstances are: (1) Outages of the EPA's CDX or CEDRI which preclude
an owner or operator from accessing the system and submitting required
reports and (2) force majeure events, which are defined as events that
will be or have been caused by circumstances beyond the control of the
affected facility, its contractors, or any entity controlled by the
affected facility that prevent an owner or operator from complying with
the requirement to submit a report electronically. Examples of force
majeure events are acts of nature, acts of war or terrorism, or
equipment failure or safety hazards beyond the control of the facility.
The EPA is providing these potential extensions in NSPS subparts VVb,
IIIa, NNNa, and RRRa (see proposed 40 CFR 60.487b (h) and (i), 40 CFR
60.615a (j) and (k), 40 CFR 60.665a(l) and (m), and 40 CFR 60.705(m)
and (n), respectively) to protect owners and operators from
noncompliance in cases where they cannot successfully submit a report
by the reporting deadline for reasons outside of their control. In both
circumstances, the decision to accept the claim of needing additional
time to report is within the discretion of the Administrator, and
reporting should occur as soon as possible. These potential extensions
are not necessary to add to the HON, P&R I, and P&R II because they
were recently added to 40 CFR part 63, subpart A, General Provisions at
40 CFR 63.9(k).
    The electronic submittal of the reports addressed in these proposed
rulemakings will increase the usefulness of the data contained in those
reports, is in keeping with current trends in data availability and
transparency, will further assist in the protection of public health
and the environment, will improve compliance by facilitating the
ability of regulated facilities to demonstrate compliance with
requirements and by facilitating the ability of delegated state, local,
tribal, and territorial air agencies and the EPA to assess and
determine compliance, and will ultimately reduce burden on regulated
facilities, delegated air agencies, and the EPA. Electronic reporting
also eliminates paper-based, manual processes, thereby saving time and
resources, simplifying data entry, eliminating redundancies, minimizing
data reporting errors, and providing data quickly and accurately to the
affected facilities, air agencies, the EPA, and the public. Moreover,
electronic reporting is consistent with the EPA's plan \159\ to
implement Executive Order 13563 and is in keeping with the EPA's
Agency-wide policy \160\ developed in response to the White House's
Digital Government Strategy.\161\ For more information on the benefits
of electronic reporting, see the document titled Electronic Reporting
Requirements for New Source Performance Standards (NSPS) and National
Emission Standards for Hazardous Air Pollutants (NESHAP) Rules,
referenced earlier in this section.
---------------------------------------------------------------------------

    \159\ EPA's Final Plan for Periodic Retrospective Reviews,
August 2011. Available at: https://www.regulations.gov/document?D=EPA-HQ-OA-2011-0156-0154.
    \160\ E-Reporting Policy Statement for EPA Regulations,
September 2013. Available at: https://www.epa.gov/sites/production/files/2016-03/documents/epa-ereporting-policy-statement-2013-09-30.pdf.
    \161\ Digital Government: Building a 21st Century Platform to
Better Serve the American People, May 2012. Available at: https://obamawhitehouse.archives.gov/sites/default/files/omb/egov/digital-government/digital-government.html.
---------------------------------------------------------------------------

4. NSPS Subpart VVa Reconsideration Issues
    In January 2008, the EPA received one petition for reconsideration
of the NSPS subpart VVa rulemaking pursuant to CAA section 307(d)(7)(B)
from the following petitioners: American Chemistry Council, American
Petroleum Institute, and National Petrochemical and Refiners
Association (now the American Fuel and Petrochemical Manufacturers).
See section II.A.3 of this preamble for additional details about this
petition for reconsideration. On June 2, 2008, the EPA indicated (73 FR
31372) that it would be publishing a Federal Register notice in
response to the petition for reconsideration on: (1) The clarification
of the definition of process unit in subparts VV, VVa, GGG, and GGGa;
(2) the assignment of shared storage vessels to specific process units
in subparts VV, VVa, GGG, and GGGa at 40 CFR 60.481a and 40 CFR 60.482-
1a(g); (3) the monitoring of connectors in subpart VVa at 40 CFR
60.482-11a; and (4) the definition of capital expenditure in subpart
VVa at 40 CFR 60.481a. These provisions were stayed pending resolution
of the reconsideration.\162\ This action does not respond to the
reconsideration of NSPS subparts GGG and GGGa, as the EPA is not
reviewing those subparts in this action and instead is only proposing
to address issues 1 through 4 for subparts VV and VVa.
---------------------------------------------------------------------------

    \162\ The EPA only granted reconsideration of issues 2 through 4
in their March 4, 2008 letter to petitioners, however, we are
proposing reconsideration on issue 1 (the clarification of the
definition of process unit) as well because of its reliance on issue
2 (the assignment of shared storage vessels to specific process
units).
---------------------------------------------------------------------------

    On November 16, 2007, the EPA promulgated amendments to the NSPS
subpart VV as well as new equipment leak requirements in NSPS subpart
VVa.

As part of the rulemaking, the EPA finalized a definition for ``process
unit'' that included a phrase that a process unit ``includes all
equipment as defined in this subpart'' which was intended to clarify
what equipment was covered by the rule. However, petitioners stated
that the ``EPA must reconsider its `clarification' of the definition of
process unit'' because ``the new process unit definition is
inconsistent with the originally promulgated definition.'' The
petitioners alleged that the new definition ``substantially expands''
the definition of process unit, thereby expanding applicability of the
NSPS ``to equipment not previously subject to those requirements.''
They also state that because the EPA characterized this change as a
``clarification,'' we failed to solicit and consider public comments on
the impacts of this requirement for both existing and new SOCMI
facilities. After further review, the November 16, 2007, definition is
imprecise with respect to the usage of the terms ``equipment'' versus
``components.'' Equipment is a separately defined term and should not
be included within the definition of process unit to establish
applicability. The reader instead should be able to refer to 40 CFR
60.480(a) (for NSPS subpart VV) and 40 CFR 60.480a(a) (for NSPS subpart
VVa) for applicability and designation of the affected facility and
refer to 40 CFR 60.481 (for NSPS subpart VV) and 40 CFR 60.481a (for
NSPS subpart VVa) for definitions of terms used within the
applicability section. Therefore, we are proposing to revert back to
the same definition for ``process unit'' that is currently being used
in NSPS subpart VV and NSPS subpart VVa according to the stay
requirements. For NSPS subpart VV, we are proposing that ``process
unit'' means components assembled to produce, as intermediate or final
products, one or more of the chemicals listed in 40 CFR 60.489 of this
part. A process unit can operate independently if supplied with
sufficient feed or raw materials and sufficient storage facilities for
the product. For NSPS subpart VVa, we are proposing that ``process
unit'' means components assembled to produce, as intermediate or final
products, one or more of the chemicals listed in 40 CFR 60.489a of this
part. A process unit can operate independently if supplied with
sufficient feed or raw materials and sufficient storage facilities for
the product. These proposed definitions for ``process unit'' for NSPS
subparts VV and VVa avoid accidentally retroactively expanding coverage
of NSPS subparts VV and VVa to previously uncovered facilities.
    Also, as part of the November 16, 2007 rulemaking, the EPA
finalized procedures at 40 CFR 60.482-1(g) (for NSPS subpart VV) and 40
CFR 60.482-1a(g) (for NSPS subpart VVa) intended to clarify how to
assign storage vessels that are shared among multiple process units to
a specific process unit. The EPA also revised the process unit
definition at 40 CFR 60.481 (for NSPS subpart VV) and 40 CFR 60.481a
(for NSPS subpart VVa) because of its reliance upon the new provision
on the allocation of shared storage vessels. Petitioners stated that
the EPA did not propose its method for addressing shared storage
vessels in the proposed rules published November 7, 2006, giving no
opportunity for public comment. The petitioners alleged that the
allocation of shared storage vessels is a new requirement ``that cannot
lawfully be imposed, with or without notice and comment, on existing
sources.'' After further review, we are proposing that a method for
assigning shared storage vessels to specific process units is not
needed. Therefore, we are proposing to remove the requirements in 40
CFR 60.482-1(g) (for NSPS subpart VV) and 40 CFR 60.482-1a(g) (for NSPS
subpart VVa). For sources subject to NSPS subparts VV and VVa, any
storage vessel that is located within the battery limits \163\ of a
process unit is already associated with that process unit; therefore,
allocation is not necessary. We are soliciting comment on this proposed
decision, specifically regarding situations when allocation would be
necessary.
---------------------------------------------------------------------------

    \163\ Statements made in the 1981 proposal preamble (46 FR 1136,
January 5, 1981) provide our clear intent of the components included
in the definition of process unit. First, the EPA specifically
stated that ``[a] process unit includes intermediate storage or
surge tanks and all fluid transport equipment connecting the
reaction, separation and purification devices.'' 46 FR 1139. This
statement clarified that the definition includes components
indirectly but still integrally involved in ``producing'' the
chemical (i.e., not a reaction, separation or purification unit
operation). Second, EPA stated: ``All equipment within the battery
limits is included'' but that ``offsite fluid transport and storage
facilities are excluded.'' Id. These terms, ``within the battery
limits'' and ``offsite,'' are industry terms of art used throughout
the SOCMI and petroleum refining industry. ``Within the battery
limits'' refers to the boundary around the components assembled to
perform a specific process function or to produce a product, whereas
``offsite'' refers to locations outside the fence line of a
facility. By using these terms, the EPA was emphasizing that all
components are part of the ``process unit'' if contained within the
battery limit boundary, but are not part of the process unit if
located ``offsite.'' Id.
---------------------------------------------------------------------------

    In the November 16, 2007, rulemaking, the EPA finalized new
connector monitoring requirements for SOCMI units. Petitioners stated
that the ``EPA must reconsider its new connector monitoring
requirements for SOCMI units, as the regulated community was denied
notice of and an opportunity to comment on this requirement.'' The
Petitioners stated that the ``EPA expanded the definition of connector
in the final rule without notice and an opportunity to comment.'' The
EPA agrees that it did not include these new requirements and this new
definition in its proposal published on November 7, 2006. Therefore, we
are proposing to remove the connector monitoring provisions from NSPS
subpart VVa at 40 CFR 60.482-11a in their entirety. Instead, we are
reproposing connector monitoring provisions in NSPS subpart VVb (see
section III.C.6.b of this preamble).
    Lastly, in the November 16, 2007 rulemaking, the EPA finalized a
definition of ``capital expenditure'' in NSPS subpart VVa. Petitioners
stated that the ``EPA must reconsider its new definition of `capital
expenditure' in subpart VVa, which was never proposed and which
retroactively triggers `modification' status for facility changes
commenced since November 7, 2006.'' The petitioners' concern was
specifically limited to the retroactive application, and not
application after November 16, 2007, and they did not seek
reconsideration with respect to the change in the definition of capital
expenditure generally. Therefore, we are proposing to revise the
``capital expenditure'' definition in NSPS subpart VVa at 40 CFR
60.481a to reflect the definition used in NSPS subpart VV at 40 CFR
60.481 for owners or operators that start a new, reconstructed, or
modified affected source prior to November 16, 2007 (as is currently
required in NSPS subpart VVa due to the stayed provisions).
Specifically, we are proposing that the value of ``X'' in the capital
expenditure definition in 40 CFR 60.481a be 1982 minus the year of
construction for owners or operators that start a new, reconstructed,
or modified affected source prior to November 16, 2007, because using
any more recent year than 1982 as ``X'' in the equation would require
owners and operators to determine former (historical) capital
expenditures in order to meet modification and reconstruction
requirements. This would not be practical given that a significant
amount of time has passed since the capital expenditure provisions were
stayed. However, we are proposing to update the definition of ``capital
expenditure'' in NSPS subpart VVb for evaluating changes that occur at
existing SOCMI facilities after April 25, 2023. We are proposing that
the value of ``X'' in the

capital expenditure definition in 40 CFR 60.481b be 2023 minus the year
of construction, where the date of original construction was after
January 6, 1982, but before January 1, 2023. Where the date of original
construction was on or after January 1, 2023, but on or before April
25, 2023, we are proposing the value of X be 1.
5. Technical and Editorial Changes
    We are proposing several technical amendments and definition
revisions to improve the clarity and enforceability of certain
provisions in the HON, P&R I, and P&R II, and NSPS subpart VVa. These
additional proposed revisions and our rationale for the proposed
revisions are described in this section.
a. HON Definition Sections
    In an effort to remove redundancy and improve consistency, we are
proposing to move all of the definitions from NESHAP subparts G and H
(i.e., 40 CFR 63.111 and 40 CFR 63.161, respectively) into the
definition section of NESHAP subpart F (i.e., 40 CFR 63.101). We are
proposing new text in 40 CFR 63.111 to point to 40 CFR 63.101, as
follows: ``All terms used in this subpart shall have the meaning given
them in the Act and in subpart F of this part.'' We are proposing new
text in 40 CFR 63.161 to point to 40 CFR 63.101, as follows: ``All
terms used in this subpart shall have the meaning given them in the Act
and in subpart F of this part, except as provided in any subpart that
references this subpart.'' We are also proposing to revise certain
terms that have minor differences between their definition in these
subparts. See Table 30 for additional details. These proposed changes
will resolve inconsistencies that lead to interpretation issues between
each of these subparts. We are not proposing to combine the definitions
from NESHAP subpart I into the definitions section of NESHAP subpart F
because those definitions are specifically for negotiated non-SOCMI
processes.

          Table 30--Proposed Definition Changes To Resolve Minor Differences Between NESHAP F, G, and H
----------------------------------------------------------------------------------------------------------------
                                                                                Proposed revised
Current definition in NESHAP  subpart   Current definition in    Current definition in     definition in NESHAP
                  F                       NESHAP  subpart G        NESHAP  subpart H            subpart F
----------------------------------------------------------------------------------------------------------------
None.................................  Closed-vent system       Closed-vent system       Closed-vent system
                                        means a system that is   means a system that is   means a system that is
                                        not open to the          not open to the          not open to the
                                        atmosphere and is        atmosphere and that is   atmosphere and is
                                        composed of piping,      composed of hard-        composed of piping,
                                        ductwork, connections,   piping, ductwork,        ductwork, connections,
                                        and, if necessary,       connections and, if      and, if necessary,
                                        flow inducing devices    necessary, flow-         flow inducing devices
                                        that transport gas or    inducing devices that    that transport gas or
                                        vapor from an emission   transport gas or vapor   vapor from an emission
                                        point to a control       from a piece or pieces   point to a control
                                        device.                  of equipment to a        device.
                                                                 control device or back
                                                                 into a process.
Control device means any combustion    Control device means     Control device means     Control device means
 device, recovery device, or            any combustion device,   any equipment used for   any combustion device,
 recapture device. Such equipment       recovery device, or      recovering,              recovery device, or
 includes, but is not limited to,       recapture device. Such   recapturing, or          recapture device. Such
 absorbers, carbon adsorbers,           equipment includes,      oxidizing organic        equipment includes,
 condensers, incinerators, flares,      but is not limited to,   hazardous air            but is not limited to,
 boilers, and process heaters. For      absorbers, carbon        pollutant vapors. Such   absorbers, carbon
 process vents (as defined in this      adsorbers, condensers,   equipment includes,      adsorbers, condensers,
 section), recapture devices are        incinerators, flares,    but is not limited to,   incinerators, flares,
 considered control devices but         boilers, and process     absorbers, carbon        boilers, and process
 recovery devices are not considered    heaters. For process     adsorbers, condensers,   heaters. For process
 control devices. For a steam           vents, recapture         flares, boilers, and     vents, recapture
 stripper, a primary condenser is not   devices are considered   process heaters.         devices are considered
 considered a control device.           control devices but                               control devices but
                                        recovery devices are                              recovery devices are
                                        not considered control                            not considered control
                                        devices, and for a                                devices, and for a
                                        steam stripper, a                                 steam stripper, a
                                        primary condenser is                              primary condenser is
                                        not considered a                                  not considered a
                                        control device.                                   control device.
None.................................  First attempt at repair  First attempt at repair  First attempt at repair
                                        means to take action     means to take action     means to take action
                                        for the purpose of       for the purpose of       for the purpose of
                                        stopping or reducing     stopping or reducing     stopping or reducing
                                        leakage of organic       leakage of organic       leakage of organic
                                        material to the          material to the          material to the
                                        atmosphere.              atmosphere, followed     atmosphere, followed
                                                                 by monitoring as         by monitoring as
                                                                 specified in Sec.        specified in Sec.
                                                                 63.180 (b) and (c), as   63.180 (b) and (c), as
                                                                 appropriate, to verify   appropriate, to verify
                                                                 whether the leak is      whether the leak is
                                                                 repaired, unless the     repaired, unless the
                                                                 owner or operator        owner or operator
                                                                 determines by other      determines by other
                                                                 means that the leak is   means that the leak is
                                                                 not repaired.            not repaired.
Initial start-up means the first time  None...................  Initial start-up means   Initial start-up means
 a new or reconstructed source begins                            the first time a new     the first time a new
 production, or, for equipment added                             or reconstructed         or reconstructed
 or changed as described in Sec.                                 source begins            source begins
 63.100 (l) or (m) of this subpart,                              production. Initial      production, or, for
 the first time the equipment is put                             start-up does not        equipment added or
 into operation. Initial start-up                                include operation        changed as described
 does not include operation solely                               solely for testing       in Sec.   63.100 (l)
 for testing equipment. For purposes                             equipment. Initial       or (m) of this
 of subpart G of this part, initial                              start-up does not        subpart, the first
 start-up does not include subsequent                            include subsequent       time the equipment is
 start-ups (as defined in this                                   start-ups (as defined    put into operation.
 section) of chemical manufacturing                              in this section) of      Initial start-up does
 process units following malfunctions                            process units            not include operation
 or shutdowns or following changes in                            following malfunctions   solely for testing
 product for flexible operation units                            or process unit          equipment. For
 or following recharging of equipment                            shutdowns.               purposes of subpart G
 in batch operation. For purposes of                                                      of this part, initial
 subpart H of this part, initial                                                          start-up does not
 start-up does not include subsequent                                                     include subsequent
 start-ups (as defined in Sec.                                                            start-ups (as defined
 63.161 of subpart H of this part) of                                                     in this section) of
 process units (as defined in Sec.                                                        chemical manufacturing
 63.161 of subpart H of this part)                                                        process units
 following malfunctions or process                                                        following malfunctions
 unit shutdowns.                                                                          or shutdowns or
                                                                                following changes in
                                                                                product for flexible
                                                                                operation units or
                                                                                following recharging
                                                                                of equipment in batch
                                                                                operation. For
                                                                                purposes of subpart H
                                                                                of this part, initial
                                                                                start-up does not
                                                                                include subsequent
                                                                                start-ups (as defined
                                                                                in Sec.   63.161 of
                                                                                subpart H of this
                                                                                part) of process units
                                                                                (as defined in Sec.
                                                                                63.161 of subpart H of
                                                                                this part) following
                                                                                malfunctions or
                                                                                process unit
                                                                                shutdowns.

None.................................  Process unit has the     Process unit means a     Process unit means a
                                        same meaning as          chemical manufacturing   chemical manufacturing
                                        chemical manufacturing   process unit as          process unit as
                                        process unit as          defined in subpart F     defined in subpart F
                                        defined in this          of this part, a          of this part, a
                                        section.                 process subject to the   process subject to the
                                                                 provisions of subpart    provisions of subpart
                                                                 I of this part, or a     I of this part, or a
                                                                 process subject to       process subject to
                                                                 another subpart in 40    another subpart in 40
                                                                 CFR part 63 that         CFR part 63 that
                                                                 references this          references this
                                                                 subpart.                 subpart.
Surge control vessel means feed        Surge control vessel     Surge control vessel     Surge control vessel
 drums, recycle drums, and              means feed drums,        means feed drums,        means feed drums,
 intermediate vessels. Surge control    recycle drums, and       recycle drums, and       recycle drums, and
 vessels are used within a chemical     intermediate vessels.    intermediate vessels.    intermediate vessels.
 manufacturing process unit when in-    Surge control vessels    Surge control vessels    Surge control vessels
 process storage, mixing, or            are used within a        are used within a        are used within a
 management of flow rates or volumes    chemical manufacturing   process unit (as         chemical manufacturing
 is needed to assist in production of   process unit when in-    defined in the           process unit when in-
 a product.                             process storage,         specific subpart that    process storage,
                                        mixing, or management    references this          mixing, or management
                                        of flow rates or         subpart) when in-        of flow rates or
                                        volumes is needed to     process storage,         volumes is needed to
                                        assist in production     mixing, or management    assist in production
                                        of a product.            of flow rates or         of a product.
                                                                 volumes is needed to
                                                                 assist in production
                                                                 of a product.
----------------------------------------------------------------------------------------------------------------

    Finally, we are also proposing editorial changes that clarify
reference citations in the definitions (to properly point to the
correct HON subpart) for ``annual average concentration,'' ``annual
average flow rate,'' ``closed biological treatment process,''
``compliance date,'' ``connector,'' ``continuous record,'' ``equipment
leak,'' ``group 1 process vent,'' ``group 1 storage vessel,'' ``group 1
wastewater stream,'' ``group 2 process vent,'' ``halogenated vent
stream,'' ``in organic hazardous air pollutant service,'' ``in volatile
organic compound service,'' ``instrumentation system,'' ``point of
determination,'' ``process vent,'' ``process wastewater stream,''
``recovery device,'' ``reference control technology for storage
vessels,'' ``reference control technology for wastewater,''
``repaired,'' ``table 8 compound,'' ``table 9 compound,'' ``total
resource effectiveness index value,'' ``treatment process,''
``wastewater,'' and ``wastewater stream''.
b. Monitoring for Adsorbers That Cannot Be Regenerated and Regenerative
Adsorbers That Are Regenerated Offsite
    We are proposing to add monitoring requirements at 40 CFR
63.114(a)(5)(v), 40 CFR 63.120(d)(1)(iii), 40 CFR 63.127(b)(4), and 40
CFR 63.139(d)(5) (for HON), and 40 CFR 63.484(t), 40 CFR 63.485(x), and
40 CFR 63.489(b)(10) (for P&R I) for adsorbers that cannot be
regenerated and regenerative adsorbers that are regenerated offsite
because the HON and P&R I do not currently include specific monitoring
requirements for this type of APCD.\164\ We are proposing owners and
operators of this type of APCD use dual adsorbent beds in series. We
have prescribed a dual bed system because the use of a single bed does
not ensure continuous compliance unless the bed is replaced
significantly before breakthrough.\165\ The proposed monitoring
requirements for non-regenerative adsorbers fulfill the EPA's
obligation to establish monitoring requirements to ensure continuous
compliance with the emission limits (e.g., 98-percent control or a 20
ppm TOC outlet concentration) when owners or operators are using these
types of control devices to comply with the standards. A dual bed
system will allow one bed to be saturated before it is replaced and,
therefore, makes efficient use of the adsorber bed without exceeding
the emission limits.
---------------------------------------------------------------------------

    \164\ We did not find any P&R II facilities that have processes
controlled by adsorbers.
    \165\ We are proposing to define the term ``breakthrough'' at 40
CFR 63.101 (for HON) and 40 CFR 63.482 (for P&R I) to mean the time
when the level of HAP or TOC detected is at the highest
concentration allowed to be discharged from an adsorber system.
---------------------------------------------------------------------------

    Similar to regenerative adsorbers, in order to monitor performance
deterioration, we are proposing measurements of HAP or TOC using a
portable analyzer or chromatographic analysis for non-regenerative
absorbers. We are proposing that these measurements be taken on the
outlet of the first adsorber bed in series using a sample port; and
they be taken monthly (if the bed has at least two months of the bed
design life remaining), weekly (if the bed has between two months and
two weeks of bed design life remaining), or daily (once the bed has
less than two weeks of bed design life remaining). Also, owners and
operators would be required to establish an average adsorber bed life
from a design evaluation as well as conduct monitoring no later than 3
days after a bed is put into service as the first bed to confirm that
it is functioning properly.
    We used the EPA's cost algorithms to estimate the cost of a second
carbon adsorber bed for two adsorber scenarios. In the first scenario,
the EPA estimated the cost of a replaceable-canister type adsorber
holding 180 lbs of carbon. The total capital investment of the second
bed (including installation and auxiliary equipment) is about $6,000,
and the total annual cost is about $800. In the second scenario, we
estimated the cost of an adsorber that holds 3,000 lbs of carbon and in
which the carbon is removed and replaced by fresh carbon when needed.
The total capital investment of the second bed (including installation
and auxiliary equipment) is about $26,600, and the total annual cost is
about $2,250. We assumed no additional labor would be required for
operation and maintenance of the second adsorber bed compared to
operating and maintaining a single bed adsorber. A more thorough
discussion of this analysis is included in the document titled Analysis
of Monitoring Costs and Dual Bed Costs for Non-Regenerative Carbon
Adsorbers Used in the SOCMI Source Category that are Associated with
Processes Subject to HON and for Non-Regenerative Carbon Adsorbers that
are Associated with Processes Subject to Group I Polymers and Resins
NESHAP, which is available in the docket for this rulemaking.
    We anticipate that the use of two beds in series and the use of
monitoring will maximize the life of each bed and reduce adsorber media
replacement costs. In both scenarios described above, we assumed that
the first bed would be replaced when it reached breakthrough (i.e., its
equilibrium capacity, which is when the adsorption zone of the bed
reaches the bed outlet and the volatile

concentration in the exhaust begins to rise) based on monitoring at the
outlet of the first bed. At that time, the owner or operator would
divert the flow from the first to the second bed, the canisters or
carbon would be replaced in the first bed, and it would then be
returned to service as the second bed in the series. We did not include
the cost of replacing the canisters or the carbon in the annual costs
because the amount of carbon used would not increase as a result of
using a second bed in series. We anticipate that having two beds in
series and performing monitoring at the outlet of the first bed will
reduce the amount of adsorber media (e.g., activated carbon) used by
facilities because they will not have to replace the adsorber media
until it reaches equilibrium capacity. With only a single bed and no
monitoring, facilities would need to replace the adsorber media more
frequently based on the estimated working capacity of the bed (which is
a fraction of the equilibrium capacity) so as to maintain compliance
and to avoid exceeding outlet concentration limits.
    As previously mentioned in section III.C.3.b of this preamble, we
are also proposing these same monitoring requirements for NSPS subpart
IIIa, NNNa, and RRRa under CAA section 111(b)(1)(B). The EPA
acknowledges that these proposed requirements could be considered under
CAA section 112(d)(6) because of the specification to have two adsorber
beds in series, instead of as a proposed change to the monitoring
requirements. However, our rationale for why a second bed is needed
would not be any different if we described these proposed changes under
CAA section 112(d)(6) instead of as a monitoring change. These changes
are being proposed because the current HON and P&R I contain no
monitoring requirements for non-regenerative adsorbers.
c. Calibration Drift Assessment (Related to NSPS Subpart VVa)
    We are proposing several corrections to the calibration drift
assessment requirements in NSPS subpart VVa at 40 CFR 60.485a(b)(2).
These amendments are being proposed to: (1) Correct a regulatory
citation to read ``Sec.  60.486a(e)(8)'' instead of ``Sec.
60.486a(e)(7)''; (2) remove the extraneous sentence ``Calculate the
average algebraic difference between the three meter readings and the
most recent readings and the most recent calibration value.''; (3)
provide clarity in the mathematical step of the assessment by replacing
the sentence ``Divide this algebraic difference by the initial
calibration value and multiply by 100 to express the calibration drift
as a percentage.'' with ``Divide the arithmetic difference of the
initial and post-test calibration response by the corresponding
calibration gas value for each scale and multiply by 100 to express the
calibration drift as a percentage.''; and (4) provide clarity by making
other minor textural changes to the provisions related to the
procedures for when a calibration drift assessment shows negative or
positive drift of more than 10 percent. We note that we are proposing
these same calibration drift assessment requirements in NSPS subpart
VVb at 40 CFR 60.485b(b)(2).
d. Control of Sweep, Purge, and Inert Blankets From IFRs
    The EPA is proposing that owners and operators that use a sweep,
purge, or inert blanket between the IFR and fixed roof of a storage
vessel would be required to route emissions through a closed vent
system and control device (see proposed 40 CFR 63.119(b)(7)).
e. Overlap Provisions
    The EPA is proposing to remove the provisions that allow compliance
with certain portions of 40 CFR part 264, subpart AA or CC in lieu of
portions of NESHAP subpart G (see proposed 40 CFR 63.110(h)) because
revisions being proposed in the HON are and not reflective of the same
standards and associated monitoring, recordkeeping, and reporting
requirements for certain control devices such as flares. In addition,
requiring all facilities to have the same set of monitoring,
recordkeeping, and reporting requirements allows for better
enforceability of the rule by the EPA.
    Also, the EPA is proposing to remove the provisions that allow
compliance with certain portions of 40 CFR part 65 in lieu of portions
of NESHAP subparts G and H (see proposed 40 CFR 63.110(i) and 40 CFR
60.160(g)) because our proposed requirements for HON processes (i.e.,
requirements we are proposing for heat exchange systems, storage
vessels, process vents, transfer racks, wastewater, and equipment
leaks) are more stringent than those required by 40 CFR part 65.
f. Other Editorial Corrections
    The EPA is proposing additional changes that address technical and
editorial corrections for the HON as follows:
     The EPA is proposing to remove the word ``Organic'' before
Hazardous Air Pollutants from the 40 CFR part 63 titles of subparts F
through I to reflect the acronym NESHAP more accurately and for
consistency in naming convention across all 40 CFR part 63 subparts;
and
     The EPA is proposing to add the phrase ``and Fenceline
Monitoring for All Emission Sources'' to the title of NESHAP subpart H
to reflect the contents of the NESHAP more accurately. The EPA is
proposing to include fenceline monitoring standards in NESHAP subpart H
(see section III.C.7 of this preamble).
6. Listing of 1-bromopropane as a HAP
    On January 5, 2022, the EPA published in the Federal Register (87
FR 393) a final rule amending the list of HAP under the CAA to add 1-
bromopropane (1-BP) in response to public petitions previously granted
by the EPA. For the source categories covered by the HON, P&R I, and
P&R II, we do not believe that the inclusion of 1-BP as an organic HAP
would have any effect on the MACT standards. First, 1-BP is not a SOCMI
chemical. Furthermore, we have no information showing that 1-BP is
used, produced, or emitted to make any SOCMI chemicals regulated by the
HON, and we are unaware of any information showing that it is used,
produced, or emitted in the production of any of the polymers and
resins processes covered by the P&R I or P&R II. Accordingly, we
believe there is no further action required by the EPA needed to
address emissions of 1-BP from these source categories. We solicit
comment on this approach, and should new information submitted to the
EPA show that 1-BP is emitted from these source categories, the EPA
will consider this information in the context of developing any MACT
standards that may be needed to address emissions of 1-BP. We also note
that in many instances in the HON and P&R I, many MACT emission
standards allow facilities to comply with a total organic compound
concentration standard (e.g., 20 ppmv), which could adequately regulate
emissions of 1-BP should we receive additional information that it is
emitted from these source categories.

F. What compliance dates are we proposing, and what is the rationale
for the proposed compliance dates?

1. HON, P&R I, and P&R II
    The proposed amendments to the HON, P&R I, and P&R II in this
rulemaking for adoption under CAA section 112(d)(2) and (3) (see
section III.D of this preamble) and CAA section 112(d)(6) (see section
III.C of this preamble) are subject to the compliance deadlines
outlined in the CAA under section 112(i). The proposed amendments to
the HON and P&R I in

this rulemaking for adoption under CAA section 112(f) (see section
III.C of this preamble) are subject to the compliance deadlines
outlined in the CAA under section 112(f)(4).
    For all of the requirements we are proposing under CAA sections
112(d)(2), (3), and (d)(6), we are proposing that all existing affected
sources and all affected sources that were new sources under the
current HON and P&R I (i.e., they commenced construction or
reconstruction after December 31, 1992 (for HON) or after June 12, 1995
(for P&R I), and on or before April 25, 2023), must comply with all of
the amendments no later than 3 years after the effective date of the
final rule, or upon startup, whichever is later. For existing sources,
CAA section 112(i) provides that the compliance date shall be as
expeditious as practicable, but no later than 3 years after the
effective date of the standard. (``Section 112(i)(3)'s three-year
maximum compliance period applies generally to any emission standard .
. . promulgated under [section 112].'' Association of Battery Recyclers
v. EPA, 716 F.3d 667, 672 (D.C. Cir. 2013)). In determining what
compliance period is as expeditious as practicable, we consider the
amount of time needed to plan and construct projects and change
operating procedures. As provided in CAA section 112(i) and 5 U.S.C.
801(3), all new affected sources that commenced construction or
reconstruction after April 25, 2023 would be required to comply with
these requirements within 60 days after the publication of the final
amendments to the HON, P&R I, and P&R II standards or upon startup,
whichever is later.
    For all of the requirements we are proposing under CAA sections
112(f), we are proposing a compliance date of 2 years after the
effective date of the final rule, or upon startup, whichever is later
for all existing affected sources and for all affected sources that
were new sources under the current HON and P&R I (i.e., they commenced
construction or reconstruction after December 31, 1992 (for HON) or
after June 12, 1995 (for P&R I), and on or before April 25, 2023, to
comply with the proposed EtO requirements (for HON) and the proposed
chloroprene requirements (for P&R I affected sources producing
neoprene). For all new affected sources that commence construction or
reconstruction after April 25, 2023, we are proposing owners or
operators comply with the EtO requirements (for HON) and the
chloroprene requirements (for P&R I affected sources producing
neoprene) within 60 days after the publication date of the final rule
(or upon startup, whichever is later).
a. Rationale for Proposed Compliance Dates of Proposed CAA Section
112(d)(2) and (3) Amendments
    We are proposing new operating and monitoring requirements for the
HON and P&R I under CAA section 112(d)(2) and (3). We anticipate that
these requirements would require the installation of new flare
monitoring equipment, and we project most CMPUs and EPPUs would install
new control systems to monitor and adjust assist gas (air or steam)
addition rates. Similar to the addition of new control equipment, these
new monitoring requirements for flares would require engineering
evaluations, solicitation and review of vendor quotes, contracting and
installation of the equipment, and operator training. Installation of
new monitoring and control equipment on flares will require the flare
to be taken out of service. Depending on the configuration of the
flares and flare header system, taking the flare out of service may
also require a significant portion of the CMPU or EPPU to be shutdown.
Therefore, for all existing affected sources, and all new affected
sources under the current HON and P&R I that commenced construction or
reconstruction after December 31, 1992 (for HON) or after June 12, 1995
(for P&R I), and on or before April 25, 2023, we are proposing that it
is necessary to provide 3 years after the publication date of the final
rule (or upon startup, whichever is later) for owners or operators to
comply with the new operating and monitoring requirements for flares.
For all new affected sources that commence construction or
reconstruction after April 25, 2023, we are proposing owners or
operators comply with the new operating and monitoring requirements for
flares within 60 days after the publication date of the final rule (or
upon startup, whichever is later).
    Under CAA section 112(d)(2) and (3), we are proposing new vent
control requirements for bypasses for the HON and P&R I. These
requirements would typically require the addition of piping and
potentially new control requirements. As these vent controls would most
likely be routed to the flare, we are proposing, for all existing
affected sources, and all new affected sources under the current HON
and P&R I that commenced construction or reconstruction after December
31, 1992 (for HON) or after June 12, 1995 (for P&R I), and on or before
April 25, 2023, to provide 3 years after the publication date of the
final rule (or upon startup, whichever is later) for owners or
operators to allow coordination of these bypass modifications with the
installation of the new monitoring equipment for the flares. For all
new affected sources that commence construction or reconstruction after
April 25, 2023, we are proposing owners or operators comply with the
new vent control requirements for bypasses within 60 days after the
publication date of the final rule (or upon startup, whichever is
later).
    For atmospheric PRD in HAP service, we are establishing a work
practice standard in the HON and P&R I that requires a process hazard
analysis and implementation of a minimum of three redundant measures to
prevent atmospheric releases. Alternately, owners or operators may
elect to install closed-vent systems to route these PRDs to a flare,
drain (for liquid thermal relief valves), or other control system. We
anticipate that sources will need to identify the most appropriate
preventive measures or control approach; design, install, and test the
system; install necessary process instrumentation and safety systems;
and may need to time installations with equipment shutdown or
maintenance outages. Therefore, for all existing affected sources, and
all new affected sources under the current HON and P&R I that commenced
construction or reconstruction after December 31, 1992 (for HON) or
after June 12, 1995 (for P&R I), and on or before April 25, 2023, we
are proposing a compliance date of 3 years from the publication date of
the final rule (or upon startup, whichever is later) for owners or
operators to comply with the work practice standards for atmospheric
PRD releases. For all new affected sources that commence construction
or reconstruction after April 25, 2023, we are proposing owners or
operators comply with the work practice standards for atmospheric PRD
releases within 60 days after the publication date of the final rule
(or upon startup, whichever is later).
    We are also establishing work practice standards in the HON and P&R
I for maintenance activities. We anticipate sources will need time to
review and update their standard operating procedures for maintenance
activities; identify the most appropriate preventive measures or
control approaches; design, install, and test the control systems; and
install necessary process instrumentation and safety systems if so
required. Therefore, for all existing affected sources, and all new
affected sources under the current HON and P&R I that commenced
construction or reconstruction after December 31, 1992

(for HON) or after June 12, 1995 (for P&R I), and on or before April
25, 2023, we are proposing a compliance date of 3 years from the
publication date of the final rule (or upon startup, whichever is
later) for owners or operators to comply with the work practice
standards for maintenance activities. For all new affected sources that
commence construction or reconstruction after April 25, 2023, we are
proposing owners or operators comply with the work practice standards
for maintenance activities within 60 days after the publication date of
the final rule (or upon startup, whichever is later).
    Under CAA section 112(d)(2) and (3), we are also proposing new
dioxins and furans emission limits for the HON, P&R I, and P&R II. The
proposed provisions may require additional time to plan, purchase, and
install equipment for dioxins and furans control. Therefore, for all
existing affected sources, and all new affected sources under the
current HON, P&R I, and P&R II that commenced construction or
reconstruction after December 31, 1992 (for HON), or after May 16, 1994
(for P&R II), or after June 12, 1995 (for P&R I), and on or before
April 25, 2023, we are proposing a compliance date of 3 years from the
publication date of the final rule (or upon startup, whichever is
later) for owners or operators to comply with the dioxins and furans
emission limits. For all new affected sources that commence
construction or reconstruction after April 25, 2023, we are proposing
owners or operators comply with the dioxins and furans emission limits
within 60 days after the publication date of the final rule (or upon
startup, whichever is later).
    Other amendments we are proposing under CAA section 112(d)(2) and
(3) include LDAR requirements for HON and P&R I pressure vessels,
process vent control requirements for certain HON and P&R I surge
control vessels and bottoms receivers, control requirements for certain
HON transfer racks with an operating pressure greater than 204.9 kPa,
and a LDAR program for P&R II heat exchange systems for BLR and WSR
sources and equipment leaks for WSR sources in P&R II. Any of these
proposed provisions may require additional time to plan, purchase, and
install equipment for emissions control; and even if not, the EPA
recognizes the confusion that multiple different compliance dates for
individual requirements would create and the additional burden such an
assortment of dates would impose. Therefore, for all existing affected
sources, and all new affected sources under the current rules that
commenced construction or reconstruction after December 31, 1992 (for
HON), or after May 16, 1994 (for P&R II), or after June 12, 1995 (for
P&R I), and on or before April 25, 2023, we are proposing a compliance
date of 3 years from the publication date of the final rule (or upon
startup, whichever is later) for owners or operators to comply with
these other proposed amendments. For all new affected sources that
commence construction or reconstruction after April 25, 2023, we are
proposing owners or operators comply with these other proposed
amendments within 60 days after the publication date of the final rule
(or upon startup, whichever is later).
b. Rationale for Proposed Compliance Dates of Proposed CAA Section
112(d)(6) Amendments
    As a result of our technology review for HON and P&R I heat
exchange systems, we are proposing to replace the existing HON and P&R
I leak definition and monitoring method with a new leak definition and
monitoring method. We project some owners and operators would require
engineering evaluations, solicitation and review of vendor quotes,
contracting and installation of monitoring equipment, and operator
training. In addition, facilities will need time to read and understand
the amended rule requirements and update standard operating procedures.
Therefore, we are proposing that all existing affected sources, and all
new affected sources under the current rules that commenced