facilities that use facility-specific, recipe-specific gas utilization
and by-production formation rates, we are proposing that the following
records be maintained: documentation that the rates were measured using
the 2006 ISMI Guidelines, documentation that the measurements made are
representative of fluorinated GHG and N2O emitting

processes at the facility, and the date and results of the initial and
any subsequent tests to determine process tool gas utilization and by-
product formation rates.
    For those facilities that are reporting controlled emissions, we
propose that the following records be kept: documentation to certify
that each abatement device used at the facility is installed,
maintained, and operated in accordance with manufacturers'
specifications; records of the uptime and the calculations to determine
uptime; abatement system calibration and maintenance records;
documentation for the EPA default DRE value or a properly measured DRE.
    These records consist of values that are directly used to calculate
the emissions that are reported and are necessary to enable
verification that the GHG emissions monitoring and calculations are
done correctly.

B. Fluorinated Gas Production

1. Overview of Reporting Requirements
    Under this proposal, subpart L would require facilities that
produce fluorinated gases to report their fluorinated GHG emissions
from fluorinated gas production and transformation and from fluorinated
GHG destruction. Fluorinated gases include fluorinated GHGs (HFCs,
PFCs, SF6, NF3, HFEs, etc.), CFCs, and HCFCs.
Certain emissions subject to other subparts or authorities are excluded
from this subpart. Specifically, emissions of HFC-23 from HCFC-22
production are addressed under subpart O and are therefore excluded
from this subpart. Similarly, as discussed in the Final MRR, emissions
of ozone depleting substances (e.g., CFCs and HCFCs) are subject to
Title VI of the CAA and are therefore excluded from this subpart.
    Under this proposed rule, facilities would be required to estimate
their emissions from fluorinated GHG production processes using either
a mass-balance approach or an approach based on measured (or in some
cases, calculated) emission factors. Facilities would be required to
estimate their emissions from CFC and HCFC production processes and
from fluorinated gas transformation processes using an emission-factor-
based approach. Consistent with the Final MRR, this proposal would
establish an annual frequency for reporting and would include
provisions to ensure the accuracy of emissions data through monitoring,
reporting, and recordkeeping requirements. Reporting would be at the
facility level.
2. Summary of Major Changes Since Initial Proposal
    In the April 2009 proposed mandatory GHG reporting rule (74 FR
16448; April 10, 2009), the fluorinated GHG production source category
was included as proposed subpart L. That initial proposal would have
required reporting from facilities emitting more than 25,000
mtCO2e from fluorinated GHG production and other source
categories (e.g., stationary combustion). We proposed monitoring based
on a daily mass-balance or yield approach that included measurements of
the reactants and the fluorinated GHG product and byproducts. Under
that approach, facilities would have had to calculate the difference
between the expected production of each fluorinated GHG based on the
consumption of reactants and the measured production of that
fluorinated GHG, accounting for yield losses related to byproducts and
wastes and accounting for streams that were recaptured and destroyed.
Facilities would have been required to measure the various inputs and
outputs daily using scales and flow meters with an accuracy and
precision of 0.2 percent of full scale, and to measure concentrations
in streams using methods with an accuracy and precision of 5 percent.
(For more detailed information on the initial proposal, see the
fluorinated gas production section of the April 10, 2009 proposed
rule.)
    We received numerous comments on the proposed approach. Commenters
stated that there may be significant uncertainty associated with the
mass-balance approach, that EPA's stated accuracy and precision
requirement of 0.2 percent for flow meters and weigh equipment was
costly and not technically achievable for many streams, that daily
calculations were excessive and likely to introduce errors, that it was
sometimes impracticable to perform a mass-balance for more than one
reactant, and that the mass-balance approach was not appropriate for
batch processes.
    Commenters also suggested alternatives to the mass-balance
approach. Several commenters focused on the use of site-specific or
process-specific emission factors. These commenters noted that many
facilities in this source category already measure emissions during
performance testing to verify compliance with their emission limits
under other EPA regulations. Commenters also noted that some
fluorinated GHG producers currently estimate their emissions of
fluorinated GHG using the emission factor approach and that this
approach is both more cost effective and more accurate than the mass-
balance approach. One commenter using the emission factor approach
stated that the estimated uncertainty of its overall fluorinated GHG
emissions estimate was 13 percent (expressed as one standard deviation)
and that the uncertainty associated with the estimates that it would
develop using the proposed mass-balance approach would be significantly
higher. Commenters suggested both emissions testing and chemical
engineering calculations as appropriate techniques to develop site-
specific emissions factors.
    Partly in response to the comments received on the April 2009
proposed MRR (74 FR 16448; April 10, 2009), today's proposed subpart L
rule incorporates a number of changes compared to the original
proposal, including but not limited to:
     Inclusion of additional emission estimation methodologies,
including process-specific, site-specific emission factors, which allow
facilities to estimate emissions using methods that may already be in
place;
     Revisions to the mass-balance approach, including
provisions to allow monthly rather than daily monitoring; greater
flexibility in the accuracy and precision of flowmeters, weigh scales,
and concentration measurements (as long as the final estimate meets an
overall accuracy and precision requirement); and the use of one rather
than two reactants in the mass-balance equation;
     Inclusion of fluorinated GHGs emitted as a by-product of
the production of CFCs and HCFCs; and
     Inclusion of fluorinated GHGs emitted as a feedstock or
by-product of transformation processes that are not intended to produce
any fluorinated gases (when those transformation processes are co-
located with fluorinated gas production processes).
3. Definition of Source Category
    This source category covers emissions of fluorinated GHGs that
occur during the production of fluorinated gases, where fluorinated
gases include fluorinated GHGs (HFCs, PFCs, SF6,
NF3, and fluorinated ethers, among others), CFCs, and HCFCs
(except HCFC-22).\20\ It also covers emissions of

fluorinated GHGs from transformation and destruction processes that
occur at fluorinated gas production facilities. EPA estimates that
total emissions from this source category were 10.6 million metric tons
of CO2e in 2006.
---------------------------------------------------------------------------

    \20\ In the April 2009 proposal, EPA requested comment on
whether emissions of fluorinated GHGs from CFC and HCFC production
processes should be subject to the subpart L reporting requirements.
While no public comments were received on this topic, EPA has
determined that HFCs and PFCs are likely to be generated during the
production of several CFCs and HCFCs, and that the quantities
generated may be significant. According to the 2006 IPCC Guidelines
and fluorinated gas producers, production of CFCs and HCFCs can
generate and emit fluorinated GHGs such as various HFCs and some
PFCs. (These HFCs exclude HFC-23 generated during HCFC-22
production, which is already covered under Subpart O). These
emissions are by-product emissions that occur due to the chemical
similarities between HFCs, PFCs, HCFCs, and CFCs and the common use
of halogen replacement chemistry to produce them. HFC-23 generated
during HCFC-22 production is already covered under Subpart O.
---------------------------------------------------------------------------

    Emissions from fluorinated gas production facilities can occur from
vents, from leaks at flanges and connections in the production line,
and from control devices (e.g., thermal oxidizers). Undesired by-
products may be deliberately vented, and some product (or reactant) may
be vented at the same time due to imperfect separation of by-products,
products, and reactants. Emissions can also occur during occasional
service work on the production equipment, during blending and recycling
of fluorinated GHGs, and during the evacuation and filling of tanks or
other containers that are distributed by the producer (e.g., on trucks
and railcars).
    Fluorinated GHG Emissions from Fluorinated GHG Production.
Emissions that occur during fluorinated GHG production include
fluorinated GHG products that are emitted before the production
measurement and fluorinated GHG byproducts that are generated and
emitted either without or despite recapture or destruction.\21\ These
emissions are not counted as ``mass produced'' under the final
requirements for suppliers of industrial GHGs in 40 CFR part 98,
subpart OO (74 FR 56260; October 30, 2009).
---------------------------------------------------------------------------

    \21\ Byproducts that are emitted or destroyed at the production
facility are excluded from the Subpart OO definition of ``produce a
fluorinated GHG.'' Any HFC-23 generated during the production of
HCFC-22 is also excluded from this definition, even if the HFC-23 is
recaptured. However, other fluorinated GHG byproducts that are
recaptured for any reason are considered to be ``produced.''
---------------------------------------------------------------------------

    Fluorinated GHG emissions from U.S. facilities producing
fluorinated GHGs are estimated to range from 0.8 percent to 2 percent
of the amount of fluorinated GHG produced, depending on the facility.
In 2006, 12 U.S. facilities produced over 350 million metric tons
CO2e of HFCs, PFCs, SF6, and NF3, and
an additional 6 facilities produced approximately 1 million metric tons
CO2e of fluorinated anesthetics. Based on an emission rate
of 1.5 percent, facilities are estimated to have emitted approximately
5.3 million metric tons CO2e of HFCs, PFCs, SF6,
and NF3, and approximately 15,000 metric tons
CO2e of fluorinated anesthetics.
    Fluorinated GHG Emissions from CFC and HCFC Production. Our
proposal to include fluorinated GHG emissions that occur during CFC and
HCFC production processes is based on two important considerations.
First, while the quantity of by-product emissions is uncertain, we
believe that it is significant and could be similar to total estimated
emissions from fluorinated GHG production. Second, many CFC and HCFC
production processes are co-located with fluorinated GHG production
facilities, allowing for efficiencies in the application of estimation
methods and monitoring and reporting infrastructures. These issues are
discussed in more detail in the Fluorinated Gas Production Technical
Support Document in the docket for this rulemaking (EPA-HQ-OAR-2009-
0927).
    Although we do not have precise estimates of the magnitude of
fluorinated GHG emissions from production of CFCs and HCFCs, we
estimate that if CFC and HCFC production processes emitted fluorinated
GHGs equivalent to one percent of their CFC and HCFC production
(excepting HCFC-22 production), U.S. emissions from this source would
be 5.3 mtCO2e, the same as from fluorinated GHG production.
EPA requests comment on the extent to which fluorinated GHGs are
generated and emitted during CFC and HCFC production. EPA also requests
comment on the extent to which fluorinated GHGs may be generated and
emitted during production of other ozone-depleting substances such as
methyl chloroform and carbon tetrachloride and on whether such
emissions should be reported under this rule.
    CFCs and HCFCs are often produced at the same facilities that
produce fluorinated GHGs. In these cases, these facilities would need
to quantify their fluorinated GHG emissions from a few processes in
addition to those producing fluorinated GHGs. In other cases, CFCs or
HCFCs are produced at facilities that do not produce fluorinated GHGs.
In these cases, which EPA estimates include 2 facilities, the
facilities would not have been covered by the initially proposed
subpart L, but would be covered by today's proposal. This coverage is
reflected in the threshold analysis discussed below.
    Fluorinated GHG Emissions from Other Processes. Facilities
producing fluorinated gases would also be required to report emissions
of fluorinated GHG feedstocks that occur during the transformation of
these feedstocks into other fluorinated substances such as
fluoropolymers, as well as emissions of fluorinated GHGs that occur
during destruction of fluorinated GHGs that are removed from the supply
of industrial gases.
    The reasons for requiring reporting of fluorinated GHG emissions
from transformation processes that are co-located with fluorinated gas
production processes are similar to those for requiring reporting of
fluorinated GHG emissions from CFC and HCFC production. First, although
EPA does not have precise estimates of the magnitude of fluorinated GHG
emissions from transformation processes, discussions with fluoropolymer
producers indicate that these emissions do occur. Second, facilities
could apply similar methods and monitoring approaches to estimate
emissions from both fluorinated gas production and fluorinated gas
transformation. The rationale for requiring reporting of emissions from
the destruction of fluorinated GHGs that are removed from the supply of
industrial gases is discussed below under Relationship between
emissions covered under subpart L and those covered under subpart OO.
    EPA is also considering requiring reporting of fluorinated GHG
emissions from two other types of processes. The first type includes
processes (other than CFC and HCFC production processes) in which
fluorinated GHGs are neither reactants nor products of the process but
are nevertheless generated as by-products or intermediates. To the
extent that such processes may generate or emit significant amounts of
fluorinated GHGs, it may be appropriate to require reporting of those
emissions. This would be particularly true if the processes were co-
located with fluorinated GHG production processes, permitting
effiencies in the application of estimation methods and reporting
infrastructures. EPA requests comment on whether, how often, and where
such processes occur (i.e., at fluorinated gas production facilities or
elsewhere). The second type of process includes fluorinated gas
transformation processes that are not co-located with fluorinated gas
production facilities. Again, it may be appropriate to require
reporting of fluorinated GHG emissions from such processes if these
emissions are significant. EPA requests comment on both of these
options.
    Relationship between emissions covered under subpart L and those
covered under subpart OO. Subpart L would require reporting from many
of

the same facilities (fluorinated GHG producers) that are required to
report under subpart OO, which contains the industrial gas supply
reporting provisions of the final MRR. In general, subpart OO is
intended to capture the quantities of fluorinated GHGs that are
entering and leaving the U.S. supply of industrial gases,\22\ while
subpart L is intended to capture the quantities of fluorinated GHGs
emitted at fluorinated gas production facilities.
---------------------------------------------------------------------------

    \22\ Specifically, subpart OO tracks the quantities of
fluorinated GHGs that are (1) produced, (2) transformed, (3)
destroyed, (4) imported, and (5) exported.
---------------------------------------------------------------------------

    There are several areas of possible overlap between the emissions
that could be reported under this subpart and those reported under
subpart OO. The areas of overlap all concern emissions that occur at
the fluorinated GHG production facility after (downstream of) the
fluorinated GHG production measurement. These include emissions from:
     Fluorinated GHG transformation processes (including
polymerization),
     Destruction of fluorinated GHGs that are removed from the
supply of industrial gases,
     Cylinder filling (if this occurs after the production
measurement),
     Blending of fluorinated GHGs,
     Recycling or reclamation of fluorinated GHGs, and
     Evacuation of fluorinated GHG heels from returned
cylinders.
    The MRR is intended to inform a range of possible policies for
reducing emissions of GHGs, including both upstream and downstream
approaches. Under a policy that focused primarily on supply, the
fluorinated GHGs added to and subtracted from the gas supply would be
tracked, and only the on-site emissions that occurred before (upstream
of) the fluorinated GHG production measurement would need to be covered
for completeness. On-site emissions that occurred after the production
measurement would be assumed to be captured by the production
measurement. Under a policy that focused on actual emissions (i.e.,
``downstream coverage'') rather than supply, on-site emissions that
occurred both before and after the production measurement would need to
be tracked.
    Maintaining flexibility to adopt either upstream or downstream
approaches argues for some counting under L of emissions that are
counted upstream (as supply) under OO.\23\ (See the October 30, 2009
Final MRR, 74 FR 56260, for more discussion of the rationale for
including both upstream and downstream emissions under the rule.) As
noted above, EPA is proposing to require reporting of fluorinated GHG
emissions from transformation and destruction processes that are
located at fluorinated gas production facilities. However, EPA is also
considering requiring reporting of fluorinated GHG emissions from the
other activities that occur at fluorinated GHG production facilities
downstream of the production measurement. EPA requests comment on the
magnitude of these other on-site emissions and on whether or not they
should be required to be reported under subpart L.
---------------------------------------------------------------------------

    \23\ In theory, it might be possible to track emissions from
transformation and destruction simply using quantities reported
under OO. However, this would require that (1) fluorinated GHGs that
are produced only to be transformed or destroyed be tracked
separately, (2) production, transformation, and destruction be
measured to very good precision and accuracy (e.g., 0.2 percent),
and (3) that no by-products be formed or emitted during these
processes. If all of these conditions were met, emissions could be
equated to the differences between production and transformation and
production and destruction. In practice, however, it would be
difficult to meet all of these conditions.
---------------------------------------------------------------------------

4. Selection of Reporting Threshold
    Under today's proposed rule, owners and operators of fluorinated
gas production facilities would be required to estimate and report GHG
emissions if those emissions, including both combustion and fluorinated
GHG emissions, would exceed 25,000 mtCO2e in the absence of
control technology (e.g., thermal oxidation).\24\
---------------------------------------------------------------------------

    \24\ Following the precedents set by other Clean Air Act
regulations, EPA is using the term ``uncontrolled'' to describe such
emissions. Specifically, EPA is proposing to define ``uncontrolled
fluorinated GHG emissions'' as a gas stream containing fluorinated
GHG which has exited the process (or process condenser, where
applicable), but which has not yet been introduced into an air
pollution control device to reduce the mass of fluorinated GHGs in
the stream. The term does not imply that the emissions are never
controlled, but is synonymous with ``pre-control emissions.''
---------------------------------------------------------------------------

    In developing the threshold, we considered multiple controlled and
uncontrolled emissions thresholds, including 1,000, 10,000, 25,000, and
100,000 metric tons CO2e. For fluorinated GHG production
processes (including fluorinated anesthetics production processes),
uncontrolled (pre-control) emissions were estimated by multiplying a
factor of 3 percent by the estimated production at each facility. For
CFC and HCFC production processes (except for HCFC-22 production
processes), uncontrolled emissions were estimated by multiplying a
factor of 2 percent by the estimated production at each facility.
Uncontrolled emissions are strongly influenced by by-product generation
rates, which are known to vary between zero and several percent for
fluorinated gas production processes; thus, these estimates are
uncertain. Controlled emissions were assumed to be half of uncontrolled
emissions at each facility. Because EPA has little information on
combustion-related emissions at fluorinated gas production facilities,
these emissions were not included in the analysis. The results of the
analysis for production of HFCs, PFCs, SF6, NF3,
CFCs, and HCFCs are shown in Tables 7 and 8 of this preamble.

  Table 7--Threshold Analysis for Fluorinated GHG Emissions From Production of HFCs, PFCs, SF6, NF3, CFCs, and
                                                      HCFCs
                                            [Uncontrolled Emissions]
----------------------------------------------------------------------------------------------------------------
                                     Total national                  Emissions covered       Facilities covered
Threshold level  (metric tons CO2e/     emissions     Number of ------------------------------------------------
                 r)                   (metric tons   facilities    Metric tons
                                         CO2e )                       CO2e        Percent     Number    Percent
----------------------------------------------------------------------------------------------------------------
1,000..............................      10,600,000          14      10,600,000        100         14        100
10,000.............................      10,600,000          14      10,600,000        100         14        100
25,000.............................      10,600,000          14      10,600,000        100         14        100
100,000............................      10,600,000          14      10,600,000        100         13         93
----------------------------------------------------------------------------------------------------------------

  Table 8--Threshold Analysis for Fluorinated GHG Emissions From Production of HFCs, PFCs, SF6, NF3, CFCs, and
                                                      HCFCs
                                             [Controlled Emissions]
----------------------------------------------------------------------------------------------------------------
                                     Total national                  Emissions covered       Facilities covered
 Threshold level (metric tons CO2e/     emissions     Number of ------------------------------------------------
                 r)                   (metric tons   facilities    Metric tons
                                         CO2e )                       CO2e        Percent     Number    Percent
----------------------------------------------------------------------------------------------------------------
1,000..............................      10,600,000          14      10,600,000        100         14        100
10,000.............................      10,600,000          14      10,600,000        100         14        100
25,000.............................      10,600,000          14      10,600,000        100         14        100
100,000............................      10,600,000          14      10,300,000         97         10         71
----------------------------------------------------------------------------------------------------------------

    As can be seen from the tables, most HFC, PFC, SF2e ,
NF3, CFC, and HCFC production facilities would be covered by
all the thresholds considered. Although we do not have facility-
specific production information for producers of fluorinated
anesthetics, we believe that few or none of these facilities are likely
to have uncontrolled emissions above the proposed threshold.
    EPA is proposing to use a threshold based on uncontrolled (pre-
control) rather than controlled (post-control) emissions to ensure that
facilities that generate significant quantities fluorinated GHGs fully
characterize and quantify their emissions, even if they initially
believe those emissions to be small. Discussions with fluorinated gas
manufacturers indicate that occasionally, fluorinated GHG by-products
may be generated and emitted from production processes unexpectedly. If
these by-products are relatively difficult to destroy (e.g.,
CF4), facilities' post-control emissions may be
significantly higher than expected.\25\ The initial scoping test
described in the next section is intended to identify the full range of
fluorinated GHGs in potentially emitted streams. Applying the full
methodologies on the basis of the initial scoping study will provide
EPA and the facilities with critical information on the extent to which
control technologies are actually reducing emissions and therefore on
the actual emissions from the facility.
---------------------------------------------------------------------------

    \25\ It is important to note that even if a threshold based on
controlled emissions were adopted, failure to report as required
when a source's actual emissions were above that threshold would be
a violation of these regulations and the Clean Air Act. Lack of test
data or other errors of omission do not excuse such violations as
the Clean Air Act is a strict liability statute.
---------------------------------------------------------------------------

    EPA is requesting comment on an alternative approach in which all
fluorinated gas production facilities, regardless of their estimated
pre-control emissions, would analyze their emissions using the initial
scoping test discussed in the next section. This approach would ensure
that facilities understood the identities, and therefore the GWPs, of
the fluorinated GHGs potentially emitted. EPA requests comment on this
option, as well as on the option of simply eliminating the threshold
for fluorinated gas production facilities and making this an ``all-in''
category.
    As is true for the source categories covered by the Final MRR,
fluorinated GHG production facilities could cease reporting if their
controlled (post-control) emissions were less than 25,000
mtCO2e per year for five consecutive years or less than
15,000 mtCO2e per year for three consecutive years. This
approach may be appropriate if control technologies are effective and
there is no evidence of unexpected uncontrolled emissions. However, EPA
requests comment on an alternative ``off-ramp'' for this source
category. Under this alternative approach, the 25,000 and 15,000
mtCO2e triggers would be based on the level of emissions
that is estimated before accounting for the use of any control
technology (e.g., thermal oxidation). EPA is requesting comment on this
approach because emissions can become quite large if the destruction
device malfunctions, is not operated properly, or is not used for some
other reason.
    As noted above, EPA estimates that under this proposal, all HFC,
PFC, SF6, and NF3 production facilities would be
covered, and few or no anesthetics producing facilities would be
covered. However, it is possible that EPA has underestimated total pre-
control emissions from anesthetics. In its threshold analysis for
fluorinated GHG production, EPA has assumed that emissions have GWPs
similar to those of the product produced. However, fluorinated
anesthetics are hydrofluoroethers, and other HFE production processes
of which EPA is aware generate by-products with higher GWPs than the
product. EPA requests comment on this issue.
    A full discussion of the threshold selection analysis is available
in the revised Fluorinated Gas Production TSD. For specific information
on costs, including unamortized first year capital expenditures, please
refer to the Economic Impact Analysis (EIA) for this rulemaking.
5. Selection of Proposed Monitoring Methods
a. Summary of Proposed Monitoring Methods
    We are proposing to allow facilities to use either a mass-balance
approach or a site-specific, process-vent-specific emission factor
(PSEF) approach to estimate their fluorinated GHG emissions from
fluorinated GHG production. Facilities would be required to use the
PSEF approach to estimate their fluorinated GHG emissions from CFC and
HCFC production or from fluorinated gas transformation. The mass-
balance approach is similar to that proposed in April, 2009, but has
been modified in some details in response to comments. Facilities using
either approach would be required to perform a one-time scoping test to
identify the fluorinated GHGs in certain emitted streams and to verify
the destruction efficiency (DE) of any destruction devices every five
years. These approaches are discussed in more detail below.
b. Initial Scoping Test of Potentially Emitted Fluorinated GHGs
    In today's action, we are proposing that facilities that produce
fluorinated gases perform an initial scoping test (proposed 40 CFR part
98.124(a)). The purpose of the scoping test is to ensure that all of
the fluorinated GHGs that occur in emitted streams are properly
identified. EPA is concerned that without the test, facilities could
mischaracterize the set of fluorinated GHGs that was emitted, leading
to inaccurate emissions estimates. We are aware that in general,
facilities will have already identified most if not all of the
fluorinated GHGs occurring in emitted streams during process design and
bench and pilot scale testing. However, as noted above, we are also
aware of

situations in which producers have analyzed process or emissions
streams and found fluorinated GHGs that they were not expecting. Such
by-product fluorinated GHGs can have high GWPs, making their
CO2-equivalent emissions significant.
    Under this requirement, which would be one-time for any given
process, facilities would be required to sample the vent(s) or
stream(s) that, alone or together, would be expected to contain all the
fluorinated GHG by-products of the process. Facilities would be
required to use EPA Method 18 (GC/ECD, GC/MS), EPA Method 320 (FTIR),
or ASTM D6348-03 (FTIR) to identify fluorinated GHGs that occur in
concentrations above 0.1 percent in emitted streams.
    For facilities using the mass-balance approach, the scoping test
could be used to determine whether some emissions that are assumed to
occur in the form of the product are actually occurring as by-products.
For facilities using the process-vent-specific emission factor approach
(PSEF), the test would identify by-products to measure in subsequent
emissions testing to develop emission factors.
    To avoid the need to survey a large number of processes with
relatively small fluorinated GHG emissions, EPA is proposing to limit
the scoping test requirement to processes that would emit more than one
metric ton per year of fluorinated GHGs before the imposition of
control technologies. We are proposing a limit in tons of fluorinated
GHGs rather than in tons of CO2e because the identities, and
therefore the GWPs, of some fluorinated GHG constituents of the stream
may not be known. Acquiring this information is the purpose of the
test. We developed the one-ton limit by starting with a limit of 10,000
mtCO2e for each process and making the reasonably
conservative assumption that the unknown fluorinated GHG could have a
GWP of 10,000. For purposes of estimating the mass of fluorinated GHG
emitted from the process, facilities could use the same types of
engineering calculations that they would use to determine whether
process vent testing was required under the PSEF approach (described in
more detail below). They could assume that the mass of carbon,
fluorine, or another relevant element is emitted in the form of
fluorinated GHGs that were previously identified in bench- or pilot-
scale testing.
    We are proposing that the one-metric-ton trigger be applied to
emissions before rather than after control because some byproducts,
particularly CF4, are very difficult to destroy. If these
by-products occurred unexpectedly in a stream and if the trigger were
applied to emissions after control, the facility would underestimate
controlled emissions. Consequently, the facility could fail to
undertake the scoping test when it was actually appropriate and could
overlook the occurrence and emissions of the by-products.\26\ We are
proposing that facilities test the streams before the control device
because emissions streams are often diluted during destruction
processes (e.g., due to fuel and air feeds), which would make it more
difficult to detect and identify fluorinated GHGs that survived the
destruction process. However, we request comment on this requirement as
well as on the scoping test requirement as a whole.
---------------------------------------------------------------------------

    \26\ For example, suppose that a facility believed that all of
the fluorinated GHG by-products from a certain process consisted of
HFCs, which its destruction device destroyed with a destruction
efficiency of 99.9 percent, but that one of these by-products was
actually CF4, which the destruction device destroyed with
an efficiency of only 50 percent. In this case, the facility could
underestimate its fluorinated GHG emissions by more than an order of
magnitude, neither seeking nor finding the CF4 that it
was actually emitting.
---------------------------------------------------------------------------

c. Mass-Balance Approach
    We are proposing that facilities producing fluorinated GHGs have
the option of monitoring emissions using the mass-balance approach. In
this approach, facilities would calculate the difference between the
expected production of each fluorinated GHG based on the consumption of
reactants and the measured production of that fluorinated GHG,
accounting for yield losses related to byproducts (including
intermediates permanently removed from the process) and wastes. Yield
losses that could not be accounted for would be attributed to emissions
of the fluorinated GHG product. This calculation could be performed for
any fluorine- or carbon-containing reactant (e.g., HF or hydrocarbon)
to estimate emissions of the fluorinated GHG product for that reactant
(i.e., the mass balance may be based on a carbon balance or a fluorine
balance). If fluorinated GHG byproducts were produced and were not
completely recaptured or completely destroyed, facilities would also
estimate emissions of each fluorinated GHG by-product.
    Because the mass-balance approach assumes that losses from the
process are emissions of the product, EPA believes that the mass-
balance approach would only be appropriate for estimating emissions
from fluorinated GHG production, not production of CFCs, HCFCs, or
polymers. (In the last three situations, the product is not a
fluorinated GHG.) However, EPA requests comment on this issue.
    To be eligible to use the mass-balance approach, facilities would
have to demonstrate that their planned measurements could meet a
statistical error limit required in the rule (described below). If the
facility could not demonstrate that it could meet the error limit, it
would have to improve the accuracy and/or precision of its monitoring
and measurement devices or opt to use another monitoring approach
offered in the rule.
    To carry out the mass-balance approach, the facility would choose a
reactant for yield calculation purposes. The facility would then weigh
or meter the mass of that reactant fed into the process, any primary
fluorinated GHG produced by the process, the mass of the reactant
permanently removed from the process (i.e., sent to the thermal
oxidizer or other equipment, not immediately recycled back into the
process), any fluorinated GHG byproducts generated, and any streams
that contain the product or fluorinated GHG byproducts and that are
recaptured or destroyed. These measurements would be tracked monthly or
more frequently and consolidated and recorded on a monthly basis. If
monitored streams (including relevant process streams, emissions
streams, and destroyed streams) included more than one component
(product, byproducts, or other materials) in more than trace
concentrations,\27\ the facility would be required to monitor
concentrations of products and byproducts in these streams. Finally,
the facility would be required to perform monthly mass-balance
calculations for each product produced.
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    \27\ EPA is proposing to define ``trace concentration'' as any
concentration less than 0.1 percent by mass of the stream.
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    Statistical Error Estimate. To estimate the statistical error
associated with use of the mass-balance approach, facilities would be
required to use error propagation, considering the accuracy and
precision of their measurements and the calculation methods of the
mass-balance approach. This approach is described in more detail in the
TSD for this proposal. Under this approach, EPA would not specify
precision and accuracy requirements for individual mass or
concentration measurements. Instead, EPA would require that the error
associated with the overall estimate of fluorinated GHG emissions fall
under 30 percent (relative error) or under 3,000 mtCO2e
(absolute error). (Both errors are expressed as halves of 95 percent
confidence intervals; for normal distributions, this is quite close

to two standard deviations). Facilities could achieve this level of
precision however they chose.
    We are proposing to require the error estimate to ensure that the
use of the mass-balance approach yields accurate emission estimates. As
observed by several groups that commented on the initial proposal, the
mass-balance approach can result in large errors if measurements of the
flow of fluorinated GHGs in one or more streams have significant
errors.\28\ We recognize that the proposed approach requires facilities
to calculate the overall error of their own estimates, which adds
complication and introduces opportunities for mistakes. We therefore
plan to develop a calculation tool that would permit reporters to
develop an error estimate, reducing both their burden and the
likelihood of errors.
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    \28\ The mass-balance approach works by subtracting the masses
of process outputs from those of process inputs. As a result, errors
that are a relatively small share of these masses become a large
share of the difference between them. Errors are particularly a
concern for streams where the fluorinated GHG is only one component
of the total flow, and where, therefore, fluorinated GHG
concentrations must be measured. In general, the accuracy and
precision of concentration measurements is expected to be
approximately +/-10 percent, although this can be as low as five
percent and as high as 20 percent, depending on the circumstances.
If this 10 percent error applies to a stream that constitutes a
significant input or (more likely) output of the process, it can
lead to an emissions estimate with a high relative error.
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    We are proposing a maximum relative error of 30 percent because
this error is comparable to that cited by the facility that has used an
emission factor approach to estimate its fluorinated GHG emissions.\29\
It is also comparable to the error that EPA calculates for a facility
with an emission rate of two percent and with good precisions and
accuracies for its mass flow measurements (+/-0.2 percent) and for its
concentration measurement (+/-10 percent) of a waste stream
constituting five percent of the process's fluorinated GHG output flow.
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    \29\ A 13 percent error expressed as a standard deviation
translates into a 26 percent error expressed as one half of a 95
percent confidence interval.
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    For facilities whose emissions constitute a very small share of
their inputs and outputs (e.g., one percent or less), a relative error
of 30 percent will be very difficult to achieve using a mass-balance
approach. At the same time, the absolute error of such a facility's
estimate may be smaller than the absolute error of a facility that
meets the relative error test but that has a higher emission rate. EPA
is therefore proposing a maximum permissible absolute error of 3,000
mtCO2e for facilities whose estimates have relative errors
greater than 30 percent. This absolute error is equivalent to 30
percent of the 10,000 mtCO2e threshold that is used
elsewhere in the subpart to establish requirements for different
sources (e.g., process vents). Under this approach, processes whose
emissions were lower than 10,000 mtCO2e could have relative
errors higher than 30 percent so long as they met the limit on absolute
error. This approach avoids penalizing processes and facilities with
low emissions. EPA requests comment on the absolute error limit of
3,000 mtCO2e. EPA is also considering a higher limit, e.g.,
5,000 mtCO2e.
    Another approach that would avoid penalizing facilities with low
emission rates would be to express the maximum relative error as a
fraction of the total mass of reactants fed into (or consumed by) the
process. For a given process, this mass would remain relatively
constant regardless of the emission rate. For the model facility
described above, with errors of 0.2 percent in its mass flow
measurements and of 10 percent in its concentration measurements, the
error of the emissions estimate relative to the total mass of reactants
is about 0.3 percent. One advantage of this approach compared to the
absolute limit is that this approach limits the relative errors for
processes with small throughputs, while the absolute limit could permit
very large relative errors for processes with small throughputs. EPA
requests comment on this approach.
    In developing the approach to specifying maximum absolute and/or
relative errors for the overall emissions estimate, we considered the
alternative of specifying the maximum allowable errors (precisions and
accuracies) of the individual measurements that feed into the mass-
balance equation. This is the approach that EPA took in the initial
proposal. This approach limits error, but it also limits flexibility, a
concern raised by several commenters. Even a facility with a relatively
large error in one stream may be able to bring the total error of its
emissions estimate to a tolerable level by improving the accuracy and
precision of other measurements that are used in the mass-balance
equation, such as the mass flows of reactants and products.
Nevertheless, EPA requests comment on the option of reverting to
specific tolerances for individual measurements that feed into the
mass-balance equation, as originally proposed.
    Choice of Reactant Whose Yield Is Measured. EPA is today proposing
to allow facilities to estimate emissions under the mass-balance
approach using one of the reactants rather than both as originally
proposed.\30\ Some fluorinated GHG producers noted that, for various
reasons, it is sometimes considerably more difficult to track the
yields of some reactants than others (e.g., HF vs. an organic
feedstock). EPA notes that facilities estimating their emissions based
on the yield of one reactant would still need to be able to demonstrate
that their estimate passed the statistical error test discussed above.
EPA requests comment on this approach.
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    \30\ Under the initial proposed rule, facilities would have been
required to perform the mass-balance calculations for each reactant
(e.g., both HF and the chlorocarbon or hydrocarbon) and to take the
average of the two results as the emissions estimate. This would be
expected to lead to the most robust estimate (i.e., the estimate
with the lowest uncertainty) if the uncertainties in both yield
calculations were similar.
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    Frequency of Measurement and Calculation. In today's proposed rule,
EPA is proposing to require that facilities using the mass-balance
approach measure and calculate their emissions monthly. A number of
fluorocarbon producers who commented on the initial proposal noted that
daily measurements were burdensome and led to large errors in the
estimates of daily emissions. They observed that many streams contain
acidic and reactive constituents such as HF, and that sampling from
these streams can create safety hazards. They also noted that daily
yield measurements can vary significantly (sometimes exceeding 100
percent) for three reasons. First, when continuous processes are first
started, there is a lag time between the time the reactants are fed
into the process and the time products emerge. Second, even after the
process has been running for a while, the quantity of material in the
process can vary based on weather, changes in production rates, and
other conditions. Third, the relatively large errors in measurements of
in-process product holding tanks (e.g., based on sight-glass readings)
have a significant impact on daily mass balances. Over time, all of
these effects smooth out, making longer term mass balances far more
reliable than daily mass balances.
    EPA has carefully considered these comments. The goal of the rule
is to gather information on annual, not daily, emissions. The advantage
of more frequent measurements and calculations is that, where mass
flows and concentrations are variable, more frequent measurements and
calculations will lead to more accurate and precise estimates than less
frequent measurements and calculations. However, in this case the
disadvantages of daily measurement and calculation

appear to outweigh the advantages. EPA believes that monthly mass-
balance calculations will lead to acceptably accurate estimates at
reasonable cost. Nevertheless, EPA requests comment on whether the
variability of the mass flows or concentrations in some production
processes may be sufficiently large to justify more frequent
measurement and calculation, e.g., weekly.
    EPA also requests comment on whether annual or less frequent
characterizations of fluorinated GHG concentrations in some streams
should be permitted under the mass-balance approach. Some fluorinated
GHG producers have stated that it is difficult to measure fluorinated
GHG concentrations in some streams. In some cases, this is because
waste streams contain hydrofluoric acid (HF), which, due to its acidity
and reactivity, can damage sampling and analytical equipment. As
discussed in the TSD, there may be technical solutions to this problem.
To the extent that these approaches could be relatively difficult or
expensive to implement, however, it might be appropriate to permit very
infrequent measurements. The disadvantage of this approach is that it
might lead to large errors, particularly for processes that vary over
time. A series of measurements might be required to (1) reduce the
error and (2) quantify the error for purposes of the statistical error
test. Such measurements would be analogous to those used to develop
emission factors.
    Reactant and Byproduct Emissions. EPA recognizes that the proposed
mass-balance approach would assume that all yield losses that are not
accounted for are attributable to emissions of the fluorinated GHG
product. In some cases, the losses may be untracked emissions (or other
losses) of reactants or fluorinated by-products. In general, EPA
understands that reactant flows are measured at the inlet to the
reactor; thus, any losses of reactant that occur between the point of
measurement and the reactor are likely to be small. However, reactants
that are recovered from the process, whether they are recycled back
into it or removed permanently, may experience some losses that the
proposed method does not account for.
    Fluorocarbon by-products, according to the IPCC Guidelines,
generally have ``radiative forcing properties similar to those of the
desired fluorochemical.'' However, EPA is aware of at least one
facility where byproducts often have much larger GWPs than the
products. In this case, assuming by-product emissions are product
emissions would lead to large errors in estimating overall fluorinated
GHG emissions. EPA believes that the initial scoping test of emitted
streams that is discussed above would help to determine whether this
was an issue for a given process.\31\ If it was, then the facility
could elect to pursue the PSEF approach rather than the mass-balance
approach for that process, or, if the facility was still interested in
pursuing the mass-balance approach, it could perform more emissions
testing to develop a robust break-out among the fluorinated GHGs
assumed to be emitted under the mass-balance approach. Such emissions
testing would be similar to that performed for the PSEF approach below,
except it would focus on the partitioning of emissions among the
various fluorinated GHGs. This approach is discussed in more detail in
the TSD. EPA requests comment on this and other possible approaches for
distinguishing between emissions of fluorinated GHG products and
emissions of fluorinated by-products under the mass-balance approach.
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    \31\ For example, if the survey indicated that attributing all
unaccounted-for losses to product emissions would lead to more than
a ten percent error in the CO2e emitted, the facility
could be required to adjust its emissions estimate to account for
by-product losses.
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    Alternative approach based on measurements of balanced element
(e.g., total fluorine). EPA is considering an alternative to the mass-
balance approach described above in which facilities would not be
required to speciate their streams (including relevant process streams,
destroyed streams, and emitted streams) monthly. Instead, they could
make monthly measurements of the total fluorine (or other element of
interest other than carbon) in the streams, e.g., by burning them. This
approach, which is described in more detail in the TSD, could be
particularly useful for processes with multiple by-products. Facilities
would still be required to perform an initial survey of the fluorinated
GHGs in the stream(s) to identify the fluorinated GHG constituents. In
addition, as discussed above, it may be appropriate to require
facilities to perform emissions testing to ensure that emissions are
properly allocated among the product and various by-products. However,
facilities would perform this testing relatively infrequently (e.g.,
every five years) rather than monthly. One potential concern regarding
this variant of the mass-balance approach is the potential difficulty
of performing analysis of combustion products that are likely to
include HF and HCl. It may be appropriate to require facilities to
validate this approach against the mass-balance method described above.
EPA requests comment on this approach.
d. Process-Specific Emission Factor Approach
    EPA is proposing an additional monitoring approach based on site-
specific, process-specific emissions factors. This approach includes
either calculation or measurement of process vent emission factors
depending on the size and fate of the emissions from the vent. Under
this approach, facilities would develop preliminary emissions estimates
to determine the level of annual uncontrolled emissions from each
process vent in processes subject to this subpart. For process vents
with uncontrolled emissions of less than 10,000 mtCO2e (or
less than 1 metric ton for emissions that include a fluorinated GHG
whose GWP does not appear in Table A-1 of subpart A), facilities could
conduct either engineering calculations or emissions testing to develop
emission factors. Facilities could also conduct either engineering
calculations or emissions testing to develop emission factors for
emissions that were vented to a destruction device demonstrated to
achieve a destruction efficiency of 99.9 percent (for fluorinated
GHGs), as long as equipment or procedures \32\ were in place to ensure
that uncontrolled emissions did not occur. For other vented emissions,
facilities would be required to conduct emissions testing to determine
the process vent emission factor.
---------------------------------------------------------------------------

    \32\ Such equipment or procedures could include, for example,
holding tank capacity, monitoring of by-pass streams, or compulsory
process shutdowns in the event the destruction device remains off
line.
---------------------------------------------------------------------------

    To estimate annual fluorinated GHG emissions from each vent,
facilities would multiply each emission factor by the appropriate
activity data and account for the use (and uptime) of destruction
devices. The fluorinated GHG emissions for all vents at the facility
would be summed to obtain the total emissions from process vents for
the facility as a whole.
    To ensure that the emissions estimate encompassed all sources of
emissions within the processes that would be subject to this subpart,
facilities using the emission factor approach would also be required to
estimate emissions from equipment leaks.\33\ Leaks would be

monitored annually using EPA Method 21 and the Protocol for Equipment
Leak Estimates U.S. Environmental Protection Agency, EPA Publication
No. EPA-453/R-95-017, November 1995.
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    \33\ As noted above, process vents are only one of the sources
of emissions from production, transformation, and destruction
processes. Another source is equipment leaks, specifically, leaks
from piping and connections. The mass-balance approach does not need
to be supplemented with equipment leak assessment because it
accounts for all emissions between the measurements of inputs and
outputs, whether these emissions occur from vents or leaks. (This
assumes that the production measurement used to estimate and report
emissions under the mass-balance approach is the same as that used
to report additions to the industrial gas supply. EPA is proposing
that these two measurements be identical.)
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    EPA is proposing less demanding measurement requirements for small
and destroyed emission streams to ensure that the effort and resources
expended to measure emissions are commensurate with the size of those
emissions. This principle has been adopted both for other source
categories in the MRR and for numerous other EPA programs. However, EPA
is requesting comment on some aspects of its proposed approaches.
    First, we request comment on the appropriateness of the
CO2e cutoff below which calculations are permitted. One
potential concern associated with this approach is that 10,000
mtCO2e equates to relatively low mass emissions of
fluorinated GHGs with high GWPs. For example, 10,000 mtCO2e
equates to 923 pounds of SF6 and 1,282 pounds of
NF3. Our understanding is that SF6 can be
detected at extremely low emission rates and concentrations, but we
request comment on whether emissions of other high-GWP compounds at
this level may be difficult to detect. An option on which we are
requesting comment is to relax the CO2e emissions cutoff and
to include an unweighted emissions cutoff (i.e., in tons of fluorinated
GHG) along with it. For example, for process vents with less than
25,000 mtCO2e uncontrolled and less than 10,000 pounds of
fluorinated GHG uncontrolled, facilities would have the option to
conduct emissions testing or engineering calculations or assessments.
    Second, EPA requests comment on its criteria for allowing use of
engineering calculations to characterize the emissions of process vents
that vent to destruction devices. EPA understands that many and perhaps
most destruction devices used at fluorinated GHG production facilities
can achieve DEs of 99.9 percent or better. EPA also understands that
many facilities have equipment or procedures in place to prevent
uncontrolled emissions, though some do not. It is important to note
that uncontrolled emissions during device downtime can reduce the
effective (time-weighted average) DE to 90 percent or less, increasing
emissions by a factor of 100 or more. However, one alternative to the
proposed approach would be to allow the use of engineering calculations
for any vent whose emissions, considering both the DE and the
historical uptime of the destruction device, fell below the 10,000
mtCO2e cutoff. For purposes of this calculation, the annual
time of uncontrolled emissions could be equated to the longest annual
time of uncontrolled emissions observed over the previous five years.
EPA requests comment on this alternative approach.
    Preliminary estimates. To develop preliminary emissions estimates
for each vent, facilities would be permitted to use the same types of
previous measurements, engineering calculations, and engineering
assessments that they would be permitted to use to develop emission
calculation factors. These are described below under ``Process-specific
Emission Calculation Factor Approach.''
    Process vent emissions testing. For process vent emissions testing,
facilities would be required to use EPA reference methods, including
EPA Method 18 and EPA Method 320, or ASTM D6348-03.\34\ Alternative
testing methods could be used if validated using EPA Method 301. EPA
reference methods are included in the rule requirements for determining
sample and velocity traverses, velocity and volumetric flow rates, gas
analysis, and stack gas moisture, along with several alternative flow
rate determination methods, such as OTM-24 and ALT-012. Commenters who
have previously estimated their emissions of fluorinated GHGs stated
that they used these approaches to do so.
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    \34\ EPA Method 320 and the ASTM method are Fourier Transform
Infrared (FTIR) methods. For such methods, compounds are identified
by characteristic spectra, and libraries providing spectra for the
range of compounds likely to be found in emissions streams can
greatly facilitate analysis. EPA requests comment on whether such
spectral libraries are available for fluorinated GHGs, and if not,
on whether EPA might play a role in assembling a spectral library
for fluorinated GHGs.
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    The testing periods would be required to include representative
process operation and to exclude atypical events (such as process
upsets or malfunctions).\35\ Within any given operating scenario
(discussed further below), the full range of process operation would be
required to be represented, i.e. the emissions data must be
representative of typical process operation while also including
process variability. Facilities would be required to consider process
parameters that may potentially cause variability of the emissions,
such as catalyst degradation, seasonal variability, raw material
suppliers, etc. For example, where a facility uses a catalyst, test
runs would have to be conducted at various points over the life of the
catalyst. The production level during the testing periods would be
required to be representative of normal operation.
---------------------------------------------------------------------------

    \35\ EPA is proposing an exception if monitoring is sufficiently
long to ensure that such events are not overrepresented in the
emission factor.
---------------------------------------------------------------------------

    To develop process-specific emissions factors, facilities would be
required to conduct at least three test runs and to analyze the
relative standard deviation (RSD) of the emission factors corresponding
to each run to determine whether additional runs were necessary. The
emission factors and their RSD would be calculated across all
fluorinated GHGs emitted from the vent in CO2e terms. If the
RSD exceeded twenty percent, the facility would be required to conduct
an additional three tests. The rationale for the RSD test is that if
the variability of a population or parameter is large, then more
samples are required to obtain a robust estimate of the mean (average)
of that parameter. EPA estimates that at a relative standard deviation
of 20 percent, an emission factor calculated as the mean of three test
runs has a 95 percent chance of being within 50 percent of the actual
mean emission rate of the process. The reasoning and calculations
behind this conclusion are discussed in more detail in the TSD.
    An alternative approach would be to conduct additional runs until
the change in the running average emission factor fell under 10
percent. This approach is similar to requirements for measuring
emission factors (slope coefficients) in subpart F (Primary Aluminum)
and could provide representative emissions from the process and address
variability. However, it has two potential drawbacks in the context of
fluorinated gas production. First, for processes whose variability is
predictable (e.g., due to catalyst age) rather than random, the fourth
sample could satisfy the running average requirement but lead to a
biased emission factor, for example if two of the four samples were
taken when the catalyst was new. Second, facilities could find it
inconvenient to analyze samples and calculate emission factors between
each test run after the first three. EPA requests comment on this
alternative approach.
    For continuous process vents, facilities would conduct 1-hour test
runs, and for batch process vents, facilities would test during
emissions episodes of the batch. We request comment on the appropriate
number of test runs to conduct for continuous and batch process vents
and the appropriate RSD that facilities should meet. We also request
comment of the appropriateness

of testing batch process vents during emissions episodes only. Another
option is to require testing of vents for the full duration of the
batch process, but this could significantly increase the expense of the
emissions test without necessarily improving its accuracy.
    Where multiple processes vent into a common vent or control device,
EPA is proposing that facilities do one of the following: sample each
process in the ducts before the emissions are combined, sample when
only one process is operating, or sample the combined emissions at
representative combinations of capacity utilizations for all the
processes. If the last option were selected, facilities would be
required to perform 3 times n test runs, where n is the number of
processes feeding into the common vent or add-on control device. The
emission factor would be calculated by dividing the total emissions by
the summed activity across the processes venting to the common vent,
and the PSEF would be applied whenever one or more of the processes was
operating.
    Process activity data would have to be collected simultaneously
with the emissions data during the emissions test. The process activity
data would be used to develop the emissions factor. Process activity
data that could be used in development of the emissions factor includes
raw material feed, amount of product produced, or other process
activity known to have a direct effect on emissions.
    Facilities would be required to define the operating scenario that
encompasses the range of operating conditions that represent typical
operation for the process and to develop representative emissions
factors for each operating scenario. To define the process operating
scenario, a facility would include information including the process
description and the specific process equipment used; the process vents,
emission episodes and durations, and the quantity of uncontrolled
fluorinated GHG emissions; the control device or destruction device
used to control emissions; and the manifolding of process vents within
the process and from other processes. Alternative operating scenarios
would also be defined for differences in operating conditions that
affect emissions. Examples of situations where process differences may
warrant separate operating scenarios include the following: Making
small volumes of a product in one set of batch process equipment part
of the year and making larger volumes in larger batch process equipment
part of the year; use of two different types of catalyst in the same
process; deliberate alterations in process conditions such as
temperature or pressure to shift the reaction to a particular product;
and making small volumes of a product in a batch process part of the
year and making large volumes in a continuous process part of the year.
A facility is required to develop a representative emissions factor for
each process operating scenario because each operating scenario for a
process will result in different emissions levels.
    In general, emissions testing during process startups and shutdowns
would not be expected to lead to representative emission factors,
because emission rates tend to fluctuate during such events. Exceptions
to this could include long-term monitoring that would not over-
represent startup or shutdown conditions in the resulting emission
factor, and monitoring specifically to obtain emission factors for
startups and shutdowns conditions. Several companies indicated that
they have analyzed the emissions profile during startup events and
during shutdown events. They found that the emission rates during these
events departed from those at steady state conditions, but that
emissions profiles were consistent between one startup event and
another.
    The uncertainty of the process-vent-specific emission factor
approach is anticipated to be roughly 10 percent; the uncertainty of
the emissions testing is estimated to be approximately 10 percent (as
calibration requirements for most test methods require 10
percent accuracy and precision), and the uncertainty of the process
activity measurement is 1 percent. While emissions testing
must continue if the first three test runs exhibit an RSD or 0.2 or
greater, the RSD is expected to be a measure of the variability of the
process rather than the error of the measurement.
    EPA is proposing that emission factors would need to be developed
before December 31, 2011, the end of the first year of reporting under
this subpart. Throughout 2011, facilities would be responsible for
gathering monthly activity data to which the emission factors, once
developed, would be applied to estimate monthly and annual emissions
from each process.
    Updates to Emission Factors. After developing their initial
process-vent-specific emission factors, facilities would be required to
update them every 5 years or when there was a process or equipment
change that would alter the process operating scenario. Process or
equipment changes would include changes in raw materials, equipment,
production levels, or operating conditions that would be expected to
affect the level of emissions. EPA is proposing periodic updates of the
emission factors because facilities that have measured and re-measured
their emission factors over a period of several years have found that
gradual, incremental changes to the process (e.g., to improve yields)
have significantly changed emission factors over time. The proposed
five-year frequency is consistent with that required for some source
categories covered in the MRR (e.g., for process vents used in HCFC-22
production processes under subpart O) but is higher than that required
for others (e.g., the 10-year frequency for measurement of slope
factors for aluminum processes). EPA requests comment on the proposed
frequency of measurement.
    An alternative to regular updates to emission factors would be
updates triggered by changes to other indicators of emission rates,
such as process yields. Under such an approach, facilities could
calculate how their emission factor would change if the change in yield
were attributable solely to a change in the emission rate. If this
change exceeded 15 percent (as a fraction of the current emission
factor), the emission factor would need to be re-measured. EPA requests
comment on this alternative.
    Measurements performed before the effective date of this rule. We
are proposing that emission factor measurements performed before the
effective date of this rule could be used to estimate GHG emissions if
the measurements were performed in accordance with the requirements of
the rule less than five years before the effective date. We believe
that it may also be appropriate to permit use of previously measured
emission factors whose measurement departed in some particulars from
the requirements of the rule but still substantially met most of the
requirements, making it likely that the emission factors were
representative. In this case, facilities could submit information to
EPA on areas where measurements departed from the requirements from the
rule, and EPA could review the measurements to verify that they still
substantially met most of the requirements. We request comment on this
option.
    Process-Specific Emission Calculation Factor Approach. As noted
above, facilities could use engineering calculations to estimate
emissions from vents that either (1) had annual emissions below 1,000
mtCO2e or (2) vented to a control device with a destruction
efficiency of 99.9 percent

and had equipment and procedures in place to prevent uncontrolled
emissions. We are proposing an emission factor approach that includes
both emissions testing and engineering calculations, with the required
approach depending on the magnitude of uncontrolled emissions from the
process vent.
    Engineering calculations use basic chemical engineering principles
and component property data to calculate emissions (and develop
emission factors) rather than actually measuring emissions.
Calculations for various emissions episodes could be conducted using
standard equations presented in EPA's Emissions Inventory Improvement
Process guidance documents, Pharmaceutical NESHAP, and Miscellaneous
Organic NESHAP. Calculations highlighted in these documents and in
codified rule text include vapor displacement, purging, heating,
depressurization, vacuum systems, gas evolution, air drying, and empty
vessel purging.
    Engineering assessments may be conducted using previous test data
or other information available on the process. Engineering assessments
include use of previous test reports where the emissions are
representative of current operating practices; bench-scale or pilot-
scale test data that are representative of full-scale process operating
conditions; design analysis based on chemical engineering principles,
measurable process parameters, or physical or chemical laws or
properties. The data used in engineering assessments must be
documented.
    Process activity data must be measured in conjunction with the
emissions estimate based on calculations and assessments. This process
activity data is needed to develop the emissions calculation factor.
    Just as for emission factor development, facilities are required to
define the operating scenario for the emission calculation factor
development. Alternative operating scenarios would also be defined for
differences in operating conditions that affect emissions. As discussed
previously for the emission factor approach, a facility would be
required to develop a representative emission calculation factor for
each process operating scenario because each operating scenario for a
process will result in different emission levels (see discussion
above).
    Facilities would update the process-vent-specific emission
calculation factors every five years or when there is a process or
equipment change that would alter the process operating scenario.
    Potential use of continuous emissions monitors to measure emissions
from vents. Another option we are considering is to require that
facilities measure emissions from fluorinated gas production facilities
using continuous emissions monitors (CEMS). Under this approach,
facilities would be required to install and operate CEMS capable of
measuring fluorinated GHGs to measure process emissions. The
requirements for the CEMs would be similar to those in subpart C,
adjusted, as appropriate, to accommodate CEMS for fluorinated gases.
One possible option is to use Fourier Transform Infrared Spectrometers
(FTIRs) in scrubber stacks to measure emissions. FTIR spectroscopy is
presently used to conduct short-term fluorinated GHG emission
measurements from processes.
    If properly selected and maintained, CEMS would be expected to
provide estimates of emissions more accurate than either the mass-
balance or the process-vent approach. However, potential drawbacks to
requiring CEMS are that they would be relatively expensive to install
and they may not tolerate the acidic and reactive environments found in
vents at many fluorinated gas production facilities. (The latter
concern might be mitigated by installing CEMS after a scrubber, if this
is practicable.) Given these potential concerns, it may be appropriate
to require CEMS for particularly large emission streams, e.g., those
resulting in emissions of more than 50,000 mtCO2e annually.
EPA requests comment on the use and implementation of CEMS at
fluorinated gas production facilities. We also request data or other
information evaluating the use of CEMS in fluorinated gas production
facilities to determine fluorinated GHG emissions.
    Equipment Leak Emissions Estimates. For completeness, EPA is
proposing that monitoring of process vents be supplemented by
monitoring of equipment leaks, whose emissions do not occur through
process vents. To estimate emissions from equipment leaks, we would
require use of EPA Method 21 and the Protocol for Equipment Leak
Estimates (EPA-453/R-95-017). Leak monitoring would be performed
annually. The Protocol includes four methods for estimating equipment
leaks. These are, from least to most accurate, the Average Emission
Factor Approach, the Screening Ranges Approach, EPA Correlation
Approach, and the Unit-Specific Correlation Approach. We are proposing
that the facility use one of the last three methods. To use these
methods, the facility would need to have (or develop) Response Factors
relating concentrations of the target fluorinated GHG (or surrogate gas
co-occurring in the stream) to concentrations of the gas with which the
leak detector is calibrated. Our understanding is that flame ionization
detectors (FIDs) are generally insensitive to fluorinated GHGs, and
that they are therefore not likely to be effective for detecting and
quantifying fluorinated GHG leaks. An exception to this would be a
situation in which the fluorinated GHG occurred in a stream along with
a substance (e.g., a hydrocarbon) to which the FID was sensitive; in
this case, the other substance could be used as a surrogate to quantify
leaks from the stream. We understand that at least two fluorocarbon
producers currently use methods in the Protocol to quantify their
emissions of fluorinated GHGs with different levels of accuracy and
precision.\36\ Other analytical techniques that are sensitive to
fluorinated compounds may be available to monitor concentrations of
equipment leaks, including photoionization, ultraviolet, infrared, and
others. EPA requests comment on the availability and use of portable
monitoring instruments for equipment leak monitoring of fluorinated
GHG.
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    \36\ One producer estimates HFC and other fluorocarbon emissions
by using the Average Emission Factor Approach. This approach simply
assigns an average emission factor to each component without any
evaluation of whether or how much that component is actually
leaking. The second producer estimates emissions using the Screening
Ranges Approach, which assigns different emission factors to
components based on whether the concentrations of the target
chemical are above or below 10,000 ppmv. This producer has developed
a Response Factor for HCFC-22, which is present in the same streams
as the HFC-23 whose leaks are being estimated. (HFC-23 emissions are
discussed in Section O of the October 30, 2009 MRR.)
---------------------------------------------------------------------------

    Another approach for monitoring leaks from pieces of equipment
includes use of the Alternative Work Practice (AWP) for EPA Method 21
(similar to monitoring requirements under 40 CFR part 60, subpart A, 40
CFR part 60.18; 40 CFR part 63, subpart A, 40 CFR part 63.11; or 40 CFR
part 65, subpart A, 40 CFR part 65.7). This approach would include
monitoring leaking equipment with an optical gas imaging instrument.
Emissions from those pieces of equipment found to be leaking could be
estimated based on emission factors. Under this approach, facilities
would be required to image each piece of equipment associated with
processes covered under subpart L and in fluorinated GHG service, and
all

emissions imaged by the optical gas imaging instrument would be
considered leaks and would be subject to emissions estimation. EPA
requests comment on the technical feasibility and accuracy of this
approach for fluorinated GHG emissions.
    Other Potentially Significant Emission Points. We are requesting
comment on the inclusion of fluorinated GHG emissions from storage
tanks, wastewater, and container filling, particularly where these
emissions occur before the production measurement at fluorinated GHG
production facilities. We anticipate that emissions from wastewater and
storage tanks would be small to insignificant due to the low solubility
of most fluorinated GHGs in water and the use of pressurized tanks for
storage. However, we request comment on the emission levels expected
from these emission points.
    Our current understanding is that most fluorinated GHG production
facilities measure their production before container filling, e.g., by
using flowmeters just upstream of the container connection to measure
the mass flowing into the containers. If this is the case, emissions
that occur during or after filling (e.g., from hoses and connections)
would have been included in the production (supply) measurement.
However, if production is measured by weighing containers before and
after filling, then emissions during container filling would not have
been included in the production measurement. In these cases, facilities
using the emission factor approach would need to quantify container
filling emissions for completeness. Possible methods for tracking these
emissions include engineering estimates, default or site-specific
emission factors, and mass balances. These methods are discussed in
more detail in the TSD.
    Destruction Device Performance Testing. EPA is proposing to require
fluorinated gas producers that destroy fluorinated GHGs to conduct an
emissions test every five years to determine the destruction efficiency
(DE) of the destruction device. As discussed further in the TSD, the
testing for determining the DE would be similar to the emissions
testing required to develop process-specific emission factors,
described above. Facilities would be required to conduct their testing
when operating at high loads reasonably expected to occur and when
destroying the most-difficult-to-destroy fluorinated GHG fed into the
device (or when destroying a surrogate that was more difficult to
destroy than that fluorinated GHG). The last point is particularly
important because some fluorinated GHGs (e.g., CF4 and
SF6) are extremely difficult to destroy; DEs determined for
other fluorinated GHGs would overestimate the destruction of these
fluorinated GHGs.
    Facilities that have conducted an emissions test on their
destruction device within the five years prior to the effective date of
the rule would be allowed to use the DE determined during that test if
the test was conducted in accordance with the proposed test
requirements. Facilities could also use the DREs determined during
principal organic hazardous constituent testing and hazardous waste
combustor testing, provided those tests determined the DRE based on the
most-difficult-to-destroy fluorinated GHG fed into the device (or based
on a surrogate that was more difficult to destroy than the most-
difficult-to-destroy fluorinated GHG).
    EPA is proposing to require reporting of fluorinated GHG emissions
from destruction of fluorinated GHGs; we request comment on whether we
should also require reporting of by-product fluorinated GHG emissions
from destruction of CFCs and HCFCs. Specifically, we request comment on
the extent to which fluorinated GHGs may be generated and emitted
during destruction of CFCs and HCFCs at facilities producing these
chemicals. Testing of destruction devices used in the electronics
sector has shown that destruction of one fluorinated compound can lead
to the emission of others under some circumstances.
6. Selection of Procedures for Estimating Missing Data
    In the event that a scale or flowmeter normally used to measure
reactants, products, by-products, or wastes fails to meet a test to
verify its accuracy or precision, malfunctions, or is rendered
inoperable, we are proposing that facilities be required to estimate
these quantities using other measurements where these data are
available. For example, facilities that ordinarily measure production
by metering the flow into the day tank could use the weight of product
charged into shipping containers for sale and distribution as a
substitute. It is our understanding that the types of flowmeters and
scales used to measure fluorocarbon production (e.g., Coriolis meters)
are generally quite reliable, and therefore that it should rarely be
necessary to rely solely on secondary production measurements. In
general, production facilities rely on accurate monitoring and
reporting of the inputs and outputs of the production process.
Nevertheless, EPA is also proposing that if a secondary mass
measurement for the stream is not available, producers can use a
related parameter and the historical relationship between the related
parameter and the missing parameter to estimate the flow.
    If concentration measurements are unavailable for some period, we
are proposing that the facility use the average of the concentration
measurements from just before and just after the period of missing
data.
    We request comment on these proposed methods for estimating missing
data.
7. Selection of Data Reporting Requirements
    Under the proposed rule, owners and operators of facilities
producing fluorinated gases would be required to report both their
fluorinated GHG emissions and the quantities used to estimate them on a
process-specific basis. They would also be required to report the
results of each scoping study, specifically, the chemical identities of
the contents of potentially emitted streams. Facilities using the mass-
balance approach would report the masses of the reactants, products,
by-products, and wastes, and, if applicable, the quantities of any
product in the by-products and/or wastes (if that product is emitted at
the facility). The chemical identities of reactants, products, and by-
products would also be reported, along with the chemical equations used
to estimate emissions. Facilities using the emission factor approach
would report the activity data used to calculate emissions (e.g., the
quantity produced, transformed, or destroyed) and the emission factors
used to estimate them. We are proposing that owners and operators
report annual totals of these quantities by process and facility.
    Where fluorinated GHG production facilities have estimated missing
data, the facility would be required to report the reason the data were
missing, the length of time the data were missing, the method used to
estimate the missing data, and the estimates of those data.
    We propose that facilities report these data because the data are
necessary to verify facilities' calculations of fluorinated GHG
emissions. We request comment on these proposed reporting requirements.
8. Selection of Records That Must Be Retained
    Maintaining records of the information used to determine the
reported GHG emissions is necessary to enable us to verify that the GHG
emissions monitoring and calculations

were done correctly. Under the proposed rule, owners and operators of
facilities producing fluorinated GHGs would be required to retain
records documenting the data reported, including records of monthly
emission estimation calculations, all data that went in to the
calculations, calibration records for flowmeters, scales, and gas
chromatographs, and documentation of emission factor development
activities. These records are necessary to verify that the GHG
emissions monitoring and calculations were performed correctly.

C. Electric Transmission and Distribution Equipment Use

    In the April 2009 proposed MRR (74 FR 16448; April 10, 2009), EPA
proposed mandatory reporting of SF6 and PFC emissions from
electric power transmission and distribution system equipment in
subpart DD. As initially proposed, this source category would comprise
electric power transmission and distribution systems that operate using
gas-insulated substations, circuit breakers and other switchgear, or
power transformers containing sulfur hexafluoride (SF6) or
perfluorocarbons (PFCs) and emissions would represent the annual
facility-wide emissions of SF6 and PFCs for the reporting
facility.
    EPA received comment from approximately 22 entities, many of whom
requested elaboration on what is included in an electric power system
for purposes of this source category as well as the relationship of an
electric power system to a facility. The requirements of 40 CFR part 98
apply to owners and operators of any ``facility''.\37\ EPA is issuing
this supplemental proposal to provide additional detail on this source
category.
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    \37\ Unless otherwise specified in an individual subpart,
facility means any physical property, plant, building, structure,
source, or stationary equipment located on one or more contiguous or
adjacent properties in actual physical contact or separated solely
by a public roadway or other public right-of-way and under common
ownership or common control, that emits or may emit any greenhouse
gas. Operators of military installations may classify such
installations as more than a single facility based on distinct and
independent functional groupings within contiguous military
properties.
---------------------------------------------------------------------------

    In doing so, our objective is to clarify and solicit further
comment on the scope of an ``electric power system'' and what
constitutes a facility for this subpart. We also provide further detail
on options we considered. We are proposing to integrate the Energy
Information Administration of the Department of Energy (EIA) list of
examples of electric power entities into the definition of a facility
for this subpart. The EIA lists the following as electric power
entities: ``a company; an electric cooperative; a public electric
supply corporation as the Tennessee Valley authority; a similar Federal
department or agency such as the Bonneville Power Administration; the
Bureau of Reclamation or the Corps of Engineers; a municipally owned
electric department offering service to the public; or an electric
public utility district (a ``PUD''); also a jointly owned electric
supply project such as the Keystone.'' \38\ We are proposing to
incorporate the EIA list of electric power entities because it is
widely used in the industry and includes the spectrum of energy supply
participants with relevant operations, i.e., vertically integrated,
generate and transmit only, transmit and distribute only, transmit only
and distribute only.
---------------------------------------------------------------------------

    \38\ Energy Information Administration of the U.S. Department of
Energy, Energy Glossary: Energy terms and definitions; http://
www.eia.gov/glossary.
---------------------------------------------------------------------------

    We are also seeking comment on whether it would be appropriate to
use the Regional Greenhouse Gas Initiative (RGGI) definition of a
transmission and/or distribution entity in our definition of electric
power system.\39\ RGGI defines an entity as ``the assets and equipment
used to transmit and distribute electricity from an electric generator
to the electrical load of a customer.'' It includes all related assets
and equipment located within the service territory of the entity,
defined as the service territory of a load-serving entity specified by
the applicable State regulatory agency. In particular, EPA seeks
comment on whether the RGGI definition includes the spectrum of
entities identified in the EIA list and captures the full universe of
SF6-emitting entities in the United States.
---------------------------------------------------------------------------

    \39\ Regional Greenhouse Gas Initiative Model Rule, 2008.
---------------------------------------------------------------------------

    EPA is requesting comments on only 40 CFR 98.300 Definition of the
Source Category in proposed subpart DD. EPA is not seeking further
comment on other elements of the initial proposal such as the selection
of the threshold and the proposed monitoring methods.
1. Definition of the Source Category
    EPA proposes to define the source category as follows: ``The
electric equipment use source category includes electric power systems
as described in this paragraph. Notwithstanding the definition of
facility in subpart A, for purposes of this subpart, ``facility'' means
an electric power system. Electric power system means the collection of
SF6- and PFC-insulated equipment linked through electric
power transmission or distribution lines and operated as an integrated
unit by one electric power entity or several entities that have a
single owner. SF6- and PFC-insulated equipment includes gas-
insulated substations, circuit breakers, other switchgear, gas-
insulated lines, and power transformers containing SF6 or
PFCs. Equipment also includes gas containers such as pressurized
cylinders, gas carts, new equipment owned but not yet installed, or
other containers.''
    The largest use of SF6 is as an electrical insulator and
interrupter in equipment intended for use in connection with
generation, transmission, distribution, and conversion of electric
energy. The gas has been employed by the electric power industry in the
United States since the 1950s because of its dielectric strength and
arc-quenching characteristics. SF6 has replaced flammable
insulating oils in many applications and allows for more compact
substations in dense urban areas. It has also facilitated expansion of
the electric power grid through long-distance transmission at high and
extra-high voltages. SF6 is used in gas-insulated
substations, circuit breakers and other switchgear, transformers, and
gas-insulated lines. The types and location of gas-insulated equipment
used varies depending on a number of technical, system design,
geographic and historic factors. Currently, there are no available
substitutes for SF6 in high-voltage applications. For
further information, see the SF6 from Electrical Equipment
TSD in the docket for this rulemaking (EPA-HQ-OAR-2009-0927).
    Since SF6 is used in pressurized equipment, unintended
emissions of SF6 occur over the life cycle of the equipment.
SF6 can escape from gas-insulated substations and switchgear
through seals, especially from older equipment. The gas can also be
released during installation, servicing, and equipment disposal.
Emissions of SF6 from electric power systems were estimated
to be 12.4 million metric tons of CO2e in 2006. Emissions
from electrical equipment manufacture and refurbishing are being
covered in subpart SS.
    PFCs are sometimes used as dielectric and as heat transfer fluids
in power transformers. PFCs are also used for retrofitting CFC-113
cooled transformers. The common PFC used in this application is
perfluorohexane (C6F14). In terms of both
absolute and carbon-weighted emissions, PFC emissions from electrical
equipment are generally believed to be much smaller than SF6
emissions. EPA does not currently have an estimate of PFC emissions
from this source category.

PFCs, however, are very potent and persistent greenhouse gases and an
accurate inventory of use and emissions from all sources is important.
Consequently, as stated in our initial proposal, we are proposing to
include emissions of PFCs in this subpart. Reference to gas-insulated
equipment implies SF6 and PFCs.
    The electric transmission and distribution equipment use source
category includes all gas-insulated electrical equipment such as gas-
insulated substations, circuit breakers, other switchgear, gas-
insulated lines, and power transformers. This equipment is used as part
of an interconnected group of electric transmission lines and
associated equipment for the movement or transfer of electric energy in
bulk between points of supply and points at which it is transformed for
delivery to the ultimate customer. This equipment, along with lines and
other associated equipment used for the movement or transfer of
electric energy, operates as part of a contemporaneous network in real-
time and in a synchronous manner to provide stable and reliable
electricity to customers.
    A clear definition of a facility for this source category is
important in order to determine whether a collection of electrical
equipment meets the reporting threshold and to ensure that double or
under reporting of emissions is minimized. In defining a facility, we
reviewed current definitions used in the CAA and by the Federal Energy
Regulatory Commission (FERC), North American Energy Reliability
Corporation (NERC), California Air Resources Board (CARB), RGGI and
EIA; consulted with industry; and reviewed current regulations relevant
to the industry. Typically, the various regulations under the CAA
define a facility as a group of emissions sources all located in a
contiguous area and under the control of the same person (or persons
under common control). The subpart A definition of facility would
require all SF6 equipment included in the facility be
located on contiguous or adjacent properties. We are proposing not to
use the exact definition of ``facility'' found in subpart A because the
completeness and accuracy of emissions data for this source category
are dependent on reporting on all equipment regardless of location. For
completeness, reporting needs to account for and report on all sources
and activities within the facility. The purpose of transmission is to
move energy over long distances. Similarly, distribution can occur over
large geographical areas. Therefore, it is neither practical nor
appropriate to exclude certain types of equipment solely based on its
lack of physical proximity. Emissions from gas-insulated equipment
occur during installation, operation, servicing and decommissioning.
Accuracy of reporting requires that emissions are systematically
neither over nor under actual emissions; consequently including all
equipment at all periods of the life cycle is necessary. Thus, EPA has
concluded that strict adherence to the subpart A definition is not
appropriate for this source category.
    In deciding where to draw the boundary between one facility and the
next, we considered the following levels of reporting: Per piece of
equipment, by substation or switchyard, corporate-level, and
aggregation of total equipment by system. Reporting per piece of
equipment was deemed costly and highly impractical for reporters.
Reporting by substation or switchyard, where multiple pieces of
equipment is often located, would also be burdensome, given that a
specific reporting protocol using the proposed mass-balance reporting
method would have to be set up for each substation, requiring cylinder
inventory and other data collection to be done on a per substation
basis. Although this may be practical for some system owners, others
have responsibility for dozens or hundreds of substations. Finally, EPA
considered corporate-level reporting based on comments submitted on our
initial proposal. We concluded, however, that given the complex and
varied corporate structures within the electric power industry that
approach would not be practical and appropriate for this source. The
full results of our assessment can be found in the SF6 from
Electrical Equipment TSD.
    For this source category, EPA is proposing to define the facility
as an ``electric power system,'' which would mean that reporting would
occur at a ``system-wide'' level. The electric power system would be
defined as all electric power equipment insulated with SF6
or PFCs regardless of location linked through electric power
transmission or distribution lines and operated as an integrated unit
by one electric power entity or several entities that have a single
owner. Reporting by the electric power system would comprise all gas-
insulated equipment located between the point of generation and the
point at which the ultimate customer receives the electricity. Such
equipment includes gas-insulated substations, circuit breakers, other
switchgear, gas-insulated lines, or power transformers containing
SF6 or PFCs. EPA proposes to define an electric power entity
as a company; an electric cooperative; a public electric supply
corporation as the Tennessee Valley Authority; a similar Federal
department or agency such as the Bonneville Power Administration; the
Bureau of Reclamation or the Corps of Engineers; a municipally owned
electric department offering service to the public; or an electric
public utility district (a ``PUD''); also a jointly owned electric
supply project such as the Keystone. Although the size of these
facilities will vary, and some are expected to cross State lines, a
facility is likely to encompass more than a thousand miles of lines and
hundreds of pieces of equipment located at multiple substations or
switchyards. Equipment also includes gas containers such as pressurized
cylinders, gas carts, new equipment owned but not yet installed, or
other containers.
    EPA believes the proposed definition of ``facility'' for this
source category is appropriate and analogous to the 40 CFR part 98
subpart A definition of a ``facility'' used for other source categories
due to the physical interconnection and operational dependence of the
components of the system. It is also consistent with the concept of a
``transmission and distribution system,'' which is a standard term used
by the industry. The transfer of energy is dependent on the collective
functioning of all components of the system which must operate as a
contemporaneous network in real-time and in a synchronous manner.
Without system-wide use of gas-insulated equipment, operation and
system reliability is not possible. Furthermore, system-wide reporting
is consistent with the reported servicing and maintenance practices of
many SF6-insulated equipment owners making this approach
less burdensome and more efficient than using a substation or per piece
of equipment source definition. This is also consistent with the
approach used by over 80 systems from across the United States that are
participating in the ``EPA SF6 Emission Reduction
Partnership for Electric Power Systems'', and has proven to be a
practical and reasonable approach for the collection of emissions data.
In addition, the burden of using the mass-balance method proposed for
monitoring is lowest at a system-wide level.
    EPA is requesting comment on whether one electric power system
should be distinguished from the next on the basis of operation,
ownership, or some combination of the two. EPA is proposing that the
electric power system be the collection of equipment operated

as an integrated unit by one electric power entity or several entities
that have a single owner because it best reflects the functional aspect
of the system (transmitting and distributing power) and emphasizes the
physical interconnection and operational dependence of the system
components. It also reflects current voluntary best practices for GHG
reporting from this source category. This proposed definition would not
relieve entities that own but do not operate equipment of the
obligation to report under 40 CFR 98.3. Regardless of the role that
operation or ownership plays in the final source category definition,
the obligation to report will apply to both owners and operators.
    Under the proposed definition of facility, total emissions would be
derived from the entire collection of servicing inventory (cylinders
stored) and gas-insulated equipment. Reporting would be based on the
aggregation of emissions of all servicing inventory and equipment.
    Installation of Electrical Equipment at Electric Power Systems. In
section E below, EPA is requesting comment on two issues related to
equipment installation and commissioning that is performed by equipment
manufacturers at electric power systems. These issues affect both users
and manufacturers of electrical equipment and could affect the
calculation methods required under both subpart DD and subpart SS.
Please see section E for a discussion of these issues.

D. Imports and Exports of Fluorinated GHGs Inside Pre-Charged Equipment
and Closed-Cell Foams

1. Overview of Reporting Requirements
    Under today's proposed rule, importers and exporters of pre-charged
equipment and closed-cell foams would be required to report their
imports and exports to EPA if either their imports or their exports
contained a total of more than 25,000 mtCO2e of fluorinated
GHGs. The reports would be similar to those required of importers and
exporters of bulk GHGs under subpart OO of the final MRR published on
October 28, 2009. In addition, equipment importers would be required to
report the types and charge sizes of equipment and the number of pieces
of each type of equipment that they imported or exported, while foam
importers would be required to report the volume of foam and
fluorinated GHG density of the foam that they imported. Importers and
exporters would report at the corporate level.
2. Summary of Initial Proposed Rule and Comments Received
    In the proposed MRR published on April 10, 2009, we did not propose
to require reporting of the quantities of GHGs imported and exported
inside products. We were concerned that it would be difficult for
importers and exporters to identify and quantify the quantities of GHGs
inside some products and that the number of importers and exporters
would be high. However, we requested comment on the option of requiring
reporting of imports and exports of HFCs and SF6 contained
in pre-charged air-conditioning, refrigeration, and electrical
equipment and in closed cell foams. We noted that for these products,
information on the size and chemical identity of the charge or blowing
agent is likely to be readily available to importers and exporters
(e.g., from nameplates affixed to equipment, servicing manuals, and
product information for foams). Moreover, as noted above, the total
quantities of imported and exported fluorinated GHGs in pre-charged
equipment and foams are significant.
    We received a range of comments on whether or not we should require
reporting of fluorinated GHGs imported or exported inside of pre-
charged equipment and closed-cell foams. Several manufacturers and
importers of fluorinated GHGs supported such a requirement, noting that
the identities and quantities of fluorinated GHGs inside equipment and
foams are well-known, that imported and exported quantities are
significant in aggregate, that the number of importers and exporters is
small, and that information on fluorinated GHGs imported or exported
inside of equipment could help to inform legislation being considered
by Congress, which would include fluorinated GHGs imported in pre-
charged equipment under emissions caps. Some of these commenters stated
that failure to require reporting of imported equipment and foams would
be unfair to domestic manufacturers, who would be subject to reporting
from which foreign manufacturers would be exempted. They observed that
this inequity could drive production offshore, harming the U.S. economy
and possibly increasing global GHG emissions if less efficient
manufacturers in developing countries took over the lost U.S.
production.
    Equipment importers and a fluorocarbon producer opposed a
requirement to report imports and exports of fluorinated GHGs in pre-
charged equipment and foams, stating that such a requirement would be
unnecessary and costly. These commenters stated that the quantities of
fluorinated GHGs inside individual pieces of equipment are small,
ranging from ounces to pounds, and that emissions from such equipment
are extremely small because the systems are hermetically sealed.
    After carefully considering the comments and available information
on imports and exports of fluorinated GHGs inside pre-charged equipment
and closed-cell foams, we are proposing to require reporting of these
imports and exports.
3. Definition of the Source Category
    This source category includes importers and exporters of pre-
charged equipment and closed-cell foams that contain fluorinated GHGs.
Pre-charged equipment includes air-conditioning equipment or equipment
components that contain HFCs and electrical equipment or equipment
components that contain SF6 or PFCs. Closed-cell foams
include closed-cell foams blown with HFC blowing agents.
    Air-conditioning and refrigeration equipment generally uses HFC
refrigerants. In this application, HFCs serve as substitutes for ozone-
depleting substances (ODSs), which are being phased out under the
Montreal Protocol and Title VI of the CAA. Because some ODSs (i.e.,
HCFCs) are only beginning to be phased out, the use of HFCs in
equipment such as window and residential air-conditioners is expected
to grow very quickly over the next decade. Imports and exports of HFC
pre-charged equipment may grow as well. Although the quantities of
chemical contained in each unit are small in absolute terms (i.e., a
few pounds or less), they are more significant in CO2-
equivalent terms, ranging up to eleven mtCO2e per unit for
pre-charged commercial air-conditioners. This significance is due to
the high GWPs of the HFCs.
    HFCs are also used as blowing agents during the manufacture of
foams. Open-cell foams are assumed to emit 100 percent of the blowing
agent in the year they are manufactured, whereas closed-cell foams emit
only a fraction of their total HFC content upon manufacture. Foam
products that are closed-cell and imported or exported as a finished
foam product therefore have potential to emit the blowing agent
remaining in the foam after manufacture. Closed cell foams that are
imported or exported include: polyurethane (PU) rigid foam used as
insulation in domestic refrigerators and freezers; commercial
refrigeration foam; PU rigid sandwich panel continuous and
discontinuous foam; extruded

polystyrene (XPS) sheet foam; and XPS boardstock foam.
    SF6 is used as an electrical insulator and arc-quenching
gas in electrical transmission equipment, including circuit breakers
and gas-insulated substations. Again, the quantities of SF6
in each unit are often small in absolute terms (around 14 pounds per
circuit breaker), but are larger in CO2-equivalent terms
(around 150 mtCO2e per circuit breaker).\40\
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    \40\ Emissions from use and manufacture of electrical equipment
are addressed under subparts DD and SS of this rule; subpart QQ
addresses only the import and export of such equipment.
---------------------------------------------------------------------------

    Our analysis indicates that the quantities of fluorinated GHGs
imported and exported inside of pre-charged equipment and foams are
significant. Imports are estimated to total about 21 million
mtCO2e, while exports are estimated to total about 8 million
mtCO2e. For further information, please see the TSD for
Imports and Exports of Pre-Charged Equipment and Foams (Revised) in the
docket for this rulemaking (EPA-HQ-OAR-2009-0927).
    We are proposing to require reporting for a number of reasons.
First, we have determined that exports and particularly imports of pre-
charged equipment and foam have a substantial impact on the total U.S.
supply of fluorinated GHGs and of industrial GHGs generally. Based on
the estimates above, imports constitute between seven and ten percent
of the net U.S. supply of fluorinated GHGs, while exports are
equivalent to between three and four percent of that total. (The range
is based on slightly different estimates of the net U.S. supply based
on bottom-up and top-down approaches.) We estimate that 22 million
pieces of equipment and 66 million board-feet of foam are imported
annually. Although the quantities of HFCs and SF6 in
individual pieces of equipment may be small in terms of the mass of
chemical, the high GWPs of these chemicals can make them significant in
CO2-equivalent terms. For example, a pre-charged residential
air conditioner (unitary) contains about 7 tons of CO2e,
while an average size circuit breaker with a shipping charge of
SF6 (20 percent of a full, operational charge) contains over
150 tons of CO2e.
    Imported and exported fluorinated GHGs are added to or subtracted
from the U.S. supply of fluorinated GHGs regardless of whether they are
imported in bulk or in equipment. Every year, a part of the U.S.
fluorinated GHG supply is used to charge new equipment or to blow
closed-cell foams. If equipment is imported already containing a
charge, that charge offsets demand that would otherwise have occurred
for fluorinated GHGs that are produced domestically or imported in
bulk. Accounting for the quantities of fluorinated GHGs in equipment
therefore significantly improves our understanding of the U.S. supply
of fluorinated GHGs. Although commenters who opposed reporting noted
that leak rates from some types of imported equipment are low, this
does not distinguish fluorinated GHGs imported inside of equipment from
fluorinated GHGs that are charged into the same type of equipment after
its import or domestic manufacture. Any imported or domestically
produced fluorinated GHG may be stored for many years inside equipment
before being emitted or destroyed.\41\
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    \41\ Even if the fluorinated GHG is recovered from the equipment
at the end of the equipment's life, it will ultimately be either
emitted or destroyed. Recycling delays emission or destruction (and
reduces demand for new fluorinated GHG), but it does not avoid it.
---------------------------------------------------------------------------

    The second reason that we are proposing to require reporting of
imports and exports of fluorinated GHGs inside pre-charged equipment
and foams is that discussions with industry experts indicate that the
numbers of importers and exporters are relatively small, limiting the
administrative burden of the rule and increasing the cost-effectiveness
of the data gathering. Experts from the air-conditioning and
refrigeration industry estimate that there are approximately 50
importers and 25 exporters of pre-charged air-conditioning and
refrigeration equipment, and experts from the electrical equipment
industry estimate that there are approximately 8 importers and 10
exporters of pre-charged electrical equipment. Based on the membership
of various trade organizations including foam manufacturers and
distributors, EPA estimates that there are approximately 50 entities
that import and 25 entities that export foams. These numbers are
considerably smaller than the number of importers and exporters of bulk
fluorinated GHGs that are covered by the final rule published October
30, 2009.
    Third, we estimate that the costs associated with identifying,
quantifying, and reporting the quantities of fluorinated GHGs imported
and exported inside pre-charged products and foams are reasonably
modest. As noted above, information on the chemical identities and
sizes of equipment charges should be readily available to importers and
exporters, and the same is true for the identities and densities of the
HFCs in foams, which strongly influence the insulating capacities of
the foams.
    Inclusion of other products that contain fluorinated GHGs. EPA's
understanding is that pre-charged equipment and closed-cell foams
account for the great majority of fluorinated GHGs that are imported in
or exported from the United States inside of products. However, a
variety of products containing fluorinated greenhouse gases
(fluorinated GHGs), nitrous oxide (N2O), and carbon dioxide
(CO2) are imported into and exported from the United States,
including, for example, aerosols containing HFCs. EPA requests comment
on the magnitude of imports and exports of these other products and on
whether such imports and exports should be reported under this subpart.
4. Selection of Reporting Threshold
    We are proposing to require that importers and exporters of
fluorinated GHGs contained in pre-charged equipment and closed cell
foams report their imports and exports if either their total imports or
their total exports, in equipment, foams, and in bulk, exceed 25,000
mtCO2e per year. This threshold is the same as that for bulk
imports and exports.
    Tables 9 and 10 of this preamble show the estimated imports and
exports (in mtCO2e) and facilities (corporations) that would
be covered under the various thresholds for imports and exports of
equipment and foam.

  Table 9--Threshold Analysis for Fluorinated GHGs Imported Inside Pre-Charged Equipment and Closed-Cell Foams
----------------------------------------------------------------------------------------------------------------
                                    HFC refrigeration/AC     SF6 electrical equipment      Closed-cell foams
                                         equipment         -----------------------------------------------------
        Threshold level         ---------------------------
                                     Imports     Importers      Imports     Importers      Imports     Importers
                                     covered       covered      covered       covered      covered       covered
----------------------------------------------------------------------------------------------------------------
1,000..........................      15,733,523         50       1,888,932          8       3,025,285         50
10,000.........................      15,733,523         50       1,888,932          8       3,025,285         50
25,000.........................      15,733,523         50       1,888,932          8       3,025,285         50
100,000........................      15,733,523         50       1,888,932          8               0          0
----------------------------------------------------------------------------------------------------------------

  Table 10--Threshold Analysis for Fluorinated GHGs Exported Inside Pre-Charged Equipment and Closed-Cell Foams
----------------------------------------------------------------------------------------------------------------
                                     Exports     Exporters      Exports     Exporters      Exports     Exporters
        Threshold level              covered       covered      covered       covered      covered       covered
----------------------------------------------------------------------------------------------------------------
1,000..........................       5,247,905         25         153,323         10       3,025,285         25
10,000.........................       5,247,905         25         107,326          5       3,025,285         25
25,000.........................       5,247,905         25               0  .........       3,025,285         25
100,000........................       5,247,905         25               0  .........       3,025,285         25
----------------------------------------------------------------------------------------------------------------

    In the absence of importer- and exporter-specific information, we
assumed that within the three general categories of products, each
importer and exporter imported or exported the same quantity of
fluorinated GHGs. (Exports of SF6 in electrical equipment
were the sole exception to this.) This assumption led to the conclusion
that 100 percent of imported and exported pre-charged equipment and
foams (except exported electrical equipment) would be reported at the
25,000 mtCO2e threshold. In fact, imports and exports are
likely to be concentrated among a subset of importers and exporters,
and fewer entities are therefore likely to report at the 25,000
mtCO2e threshold. We request comment on the distribution of
imports and exports among importers and exporters and on the likely
coverage (in percentage terms) of imported and exported equipment and
foams at the 25,000 mtCO2e threshold. An alternative
approach would be to lower the threshold or to require reporting by all
importers and exporters of pre-charged equipment and closed cell foams,
but EPA is concerned that this approach could burden many small
importers and exporters with reporting while gaining little additional
coverage of imports and exports in equipment and foams.
5. Selection of Proposed Monitoring Methods
    We are proposing to require importers and exporters of equipment
and foams to estimate their imports and exports of each fluorinated GHG
by multiplying the mass of the fluorinated GHG contained in each type
of equipment or foam by the number of pieces of equipment or by the
volume of foam, as appropriate. As noted above, we believe that
information on fluorinated GHG identity and charge size (or density,
for foams) should be readily available to importers and exporters.
    Under the current MRR, bulk importers and exporters of fluorinated
GHGs are not required to report individual shipments totaling less than
250 mtCO2e of fluorinated GHGs. This exemption was intended
to exclude small shipments, e.g., of chemical samples being shipped for
analysis, from reporting. We established the exemption after an
analysis of import and export shipments showed that it would decrease
reporting by less than 0.1 percent. We are not proposing a similar
exemption for small shipments of equipment and foams because we do not
believe it would be necessary and because we are concerned that it
might lead to the exclusion of a significant share of imports and
exports of these products. We do not believe the small-shipment
exemption would be necessary because the definition of import in
subpart A already excludes the bringing into the United States of
household effects such as refrigerators and window air conditioners. We
are concerned that the exemption may result in excluding a significant
share of imports and exports because 250 mtCO2e equates to a
large number of pieces of some types of equipment (e.g., over 1,300
household refrigerators).
6. Selection of Data To Be Reported
    EPA is proposing to require importers and exporters of pre-charged
equipment and closed cell foams to report the following:
    (1) The total mass in metric tons of each fluorinated GHG imported
or exported in pre-charged equipment or closed-cell foams.
    (2) For each type of pre-charged equipment, the identity of the
fluorinated GHG used as a refrigerant or electrical insulator, charge
size (holding charge,\42\ if applicable), and number imported or
exported.
---------------------------------------------------------------------------

    \42\ This refers to any holding charge consisting of a
fluorinated GHG. Holding charges consisting of other gases, such as
nitrogen, are not included.
---------------------------------------------------------------------------

    (3) For closed-cell foams that are imported or exported inside of
appliances, the identity of the fluorinated GHG contained in the foam,
the quantity of fluorinated GHG contained in the foam in each
appliance, and the number of appliances imported for each type of
appliance.
    (4) For closed cell-foams that are not inside of appliances, the
identity of the fluorinated GHG, the density of the fluorinated GHG in
the foam (kg fluorinated GHG/cubic foot), and the quantity of foam
imported or exported (cubic feet) for each type of closed-cell foam.
    (5) Dates on which the pre-charged equipment or closed-cell foams
were imported or exported.
    (6) Ports of entry through which the pre-charged equipment or
closed-cell foams passed.
    (7) Countries from or to which the pre-charged equipment or closed-
cell foams were imported or exported.
    We are proposing to collect this information because it is
necessary either to understand the total volume of fluorinated GHGs
imported or exported

inside of pre-charged equipment and foams (and thereby contributing to
the U.S. supply of fluorinated GHGs) or to verify submitted
information.
7. Selection of Recordkeeping Requirements
    EPA is proposing to require importers and exporters of equipment
and closed cell foams to retain the following records:
    (1) A copy of the bill of lading for the import or export,
    (2) The invoice for the import or export, and
    (3) For imports, the U.S. Customs entry form.
    This information is necessary to verify submitted information.

E. Electrical Equipment Manufacture or Refurbishment

1. Definition of the Source Category
    This source category comprises electrical equipment manufacturers
and refurbishers of SF6 or PFC-insulated closed-pressure
equipment and sealed-pressure equipment including gas-insulated
substations, circuit breakers and other switchgear, gas-insulated
lines, or power transformers containing sulfur-hexafluoride
(SF6) or perfluorocarbons (PFCs).
    Electrical equipment employed to transmit and distribute
electricity constitutes the largest use of SF6 in the world.
The dielectric strength and arc-quenching characteristics of
SF6 make it an extremely effective electrical insulator and
interrupter. For this reason, the electric power industry in the United
States has used this gas since the 1950s in both closed-pressure and
sealed-pressure equipment including gas-insulated substations, circuit
breakers and other switchgear, and gas-insulated lines. Closed-pressure
equipment requires periodic refilling (topping up) with gas during its
lifetime, whereas sealed-pressure equipment generally does not.
SF6 has replaced flammable insulating oils in many
applications and allows for more compact substations in dense urban
areas. SF6 insulated equipment has also made expansion of
the grid through transmission over significantly longer distances
economically practical. Currently, there are no available substitutes
for SF6 in this application. For further information, see
the SF6 from Electrical Equipment Manufacturers TSD in the
docket for this rulemaking (EPA-HQ-OAR-2009-0927).
    Manufacturers of gas insulated electrical equipment purchase bulk
SF6 gas to: (1) Install a holding or shipping charge in
high-voltage closed-pressure equipment, (2) ship alongside closed-
pressure equipment for topping off at installation site, (3) fill
sealed-pressure equipment with its intended lifetime supply of
SF6, and (4) develop and test equipment.
    Emissions of SF6 from equipment manufacturers can occur
during the development and testing of equipment and during equipment
filling, but emissions can also occur during the other uses of
SF6 at manufacturing facilities. Refurbishment of equipment
generally occurs at facilities used to manufacture new equipment and
emissions typically occur during the leak test operations for gas-
containing components as well as the disassembly and reassembly of
equipment.
    PFCs are sometimes used as dielectrics and heat transfer fluids in