DATE: May 10, 2012

FROM: Lisa Grogan-McCulloch, Greenhouse Gas Reporting Branch

SUBJECT: Potential Future Subpart L Options

I. Introduction

Following publication of proposed confidentiality determinations1for the Fluorinated Gas 

Production source category (subpart L), EPA received public comment that the release of 

process-specific emissions of individual fluorinated greenhouse gases (GHGs) from some 

fluorinated gas production and transformation processes may reveal trade secrets. In response to 

these comments, EPA is undertaking an in-depth analysis on whether the subpart L reporting 

requirements could be changed to mitigate these concerns without compromising the adequacy

of the data set available to the Agency to inform development of future climate policy. As part 

of this effort, we are presenting in this Memorandum potential options for changes to the subpart 

L reporting requirements should EPA determine that a change is appropriate.

There are several possible options for reporting process level emissions from fluorinated gas

production. In this memo, we have attempted to outline these options in order to be as 

comprehensive as possible. EPA is currently in the process of evaluating whether these options 

would generate an adequate data set upon which to inform future policy. Should EPA determine 

that a permanent change to the reporting requirements is appropriate, any comments received on 

this memorandum will facilitate the narrowing of options and development of a future proposal. 

II. Overview of Current Subpart L Reporting Requirements

Under the current subpart L, fluorinated gas producers are required to report GHG emissions by

process and by chemical. Specifically, facilities are currently required to report the following: 

 The total mass of each fluorinated GHG emitted from 

o each fluorinated gas production process (98.126(a)(2)(i)) , 

o each fluorinated gas transformation process that is not part of a fluorinated gas 

production process2(98.126(a)(2)(ii)),

o each fluorinated gas destruction process that is not part of a fluorinated gas 

production or transformation process (98.126(a)(2)(iii)), and 

 

1

See 77 FR 1434, January 10, 2012.

2

Facilities are also required to distinguish between transformation processes that consume fluorinated GHG 

reactants that are produced off site and those that do not. This is because fluorinated GHG reactants that are 

produced off site are reported as additions to the fluorinated GHG supply under subpart OO, and therefore 

emissions from the transformation of these reactants may be double-counted as both emissions and supply. This 

concern is not present for transformation processes that do not consume fluorinated GHG reactants produced off 

site.
2

o venting of residual fluorinated GHGs (heels) from containers returned from the 

field (98.126(a)(2)(iv)). 

 Where producers use the emission factor or emission calculation factor methods under 

section 98.123(c), they are also required to report chemical-specific emissions for each 

process vent and for equipment leaks, which reflects the fact that emissions are calculated 

separately for vents and leaks (98.126(c) and (d)). 

 Where producers use the mass-balance method under 98.123(b), they are also required to 

report emissions by the role the chemical plays in the production process (i.e., as reactant, 

product, or by-product), again reflecting the method by which emissions are calculated 

(98.126(b)(3) – (5)). 

 In addition, fluorinated gas producers are required to report, by process, the chemical 

identities of the contents of the streams (including process, emissions, and destroyed 

streams) analyzed under the initial scoping speciation at 98.124(a) as well as the location 

and function of those streams (98.126(a)(3) and (4)). 

 The first reporting under subpart L is to occur in 2012, for reporting year 2011 (RY2011).

III. Options for Reporting Emissions from Fluorinated Gas Production and 

Transformation Processes 

EPA is considering several options to address the concerns raised by the commenters on the 

proposed confidentiality determinations for subpart L. Section A below describes an approach 

under which facilities would be required to meet certain criteria as a condition for reporting their 

fluorinated GHG emissions in a less detailed manner than currently required by the rule. Section 

B describes a range of options for reporting at various levels of detail. The options described in 

Section B could be applied together with the approach described in Section A or separately.

A. Option of establishing criteria to determine the level of reporting

As discussed above, given the comments on the confidentiality rulemaking (77 FR 1434), EPA is 

considering whether EPA needs the current level of data reported from all facilities within 

subpart L, or whether EPA would have an adequate data set with which to inform future policy

by collecting this level of information from most facilities and less detailed information from 

facilities with specialized circumstances. To this end, EPA is considering an approach under 

which facilities that meet certain criteria could report their fluorinated GHG emissions in a less 

detailed manner according to one of the options outlined in Section B below. The criteria could 

include considerations such as whether a facility has a unique process or product, whether the 

facility’s process information is already in the public domain, and/or the quantity of the product 

produced. Under this option, all facilities that do not meet the criteria for reporting in a less 

detailed manner would be required to report using the current subpart L reporting requirements. 

B. Options for Reporting at Alternative Levels of Aggregation

For fluorinated gas production and transformation processes, EPA is considering a range of 

reporting options that would provide varying levels of detail regarding the source of the 

emissions (ranging from reporting by process and by emission type to reporting at the facility
3

level) and the chemicals emitted (ranging from reporting by speciated fluorinated GHG to 

reporting in CO2e). Table 1 below illustrates where the possible alternative reporting options (as 

well as the current reporting approach in the rule) fall along these two axes. To address the 

possibility that reporting chemical-specific emissions at the process level could disclose 

business-sensitive information, many of the options (represented as cells in Table 1) involve 

reporting at different levels of aggregation for the source and the chemicals. For example, under 

one option, the source would be reported at the highest level of aggregation (by facility) while 

the chemicals would be reported at the lowest level (by fluorinated GHG species). Under other 

options, the source would be reported at the lowest level of aggregation (by process and emission 

type) while the chemicals would be reported at a higher level of aggregation (e.g., by gas group 

or in terms of CO2e). In addition, different options could be combined. 

Based on Table 1, there are twelve or more individual options that could be based on different 

combinations of these levels. Rather than reviewing these individually, Section 1 focuses on the 

varying levels of aggregation for the source, while Section 2 focuses on the varying levels of 

aggregation for the chemicals. Section 3 then discusses four individual options in more detail. 

1. Levels of Aggregation for the Emissions Source

a. Reporting by process and emissions type (current requirements in subpart L)

Currently, subpart L requires facilities to report their emissions by process. In addition, they are 

required to report the identity and mass of the product produced by each production or 

transformation process. Where the emission estimation method permits, facilities are also 

required to report their emissions by emission type.

The definition of “process” in subpart L reads in part, “Process means all equipment that 

collectively functions to produce a fluorinated gas product, including an isolated intermediate 

(which is also a fluorinated gas product), or to transform a fluorinated gas product. A process
Table 1. Overview of GHG Reporting Alternative Options for Subpart L

Emission Source

G

as

In

c

r

e

asin

g

A

gg

r

eg

atio

n

By process, by 

emission type

 Vents

 Leaks

Product of 

process reported

By process, by 

emission type

Product of process 

not reported; instead 

process identified 

generically, e.g.,

 Production 

reaction A

 Production 

reaction B

 Transformation 

distillation 

process C

By Process 

only

At Facility-Level

 All production, 

transformation 

processes 

combined

By chemical Current rule

Gas groups 

(based on 

chemical 

structure OR

atmospheric 

lifetime)

CO2e

Increasing Aggregation
may consist of one or more unit operations. For the purposes of this subpart, process includes 

any, all, or a combination of reaction, recovery, separation, purification, or other activity, 

operation, manufacture, or treatment which are used to produce a fluorinated gas product.”

Emission type refers to emissions from process vents and equipment leaks. The emission factor 

and emission calculation factor methods provide separate estimates for these emissions types 

while the mass-balance method does not.

Reporting the identity and mass of the product produced by the process provides a natural means 

of identifying the process and allows EPA to compare processes that make similar products at 

different facilities. Reporting by emission type allows EPA to identify and evaluate potential 

reduction opportunities.

b. Reporting by generically identified process 

Given that some commenters have asserted that the identity of the product of the process could 

disclose sensitive business information (if the product is an intermediate), EPA is considering an 

option where facilities would identify processes generically. The process would first be 

identified as a production process, a transformation process that transformed fluorinated GHGs 

produced on site, or a transformation process that transformed fluorinated GHGs produced at 

other facilities. Within these categories, the process would be further identified as a reaction, 

separation/recovery, or packaging process, or as a combination of these. Finally, the process 

would be tagged with an identifier chosen by the facility (e.g., a letter or number) that would 

remain constant from year to year to allow year-to-year comparisons. One area where reporting

of the identity of the product of the process may not involve reporting of sensitive business 

information is where that product is a final product, whose identity would already be known to 

competitors. Compared to Option a, this option would not allow EPA to identify and compare

processes making the same product across different facilities

c. Reporting by process, with emission types reported in aggregate (across processes) 

Under this option, the emissions reported for each process would not be broken down by 

emission type. Emission type could be reported in aggregate across all processes. Under this 

approach, potential reduction opportunities for each emission type within each process would be 

more difficult to evaluate than under Options a and b. Because the relative magnitudes of 

emissions from vents and leaks are not likely to be business-sensitive, and similar sets of 

chemicals are expected to be emitted from vents and leaks for any given process, distinguishing 

between emissions from vents and leaks would not add to the risk of revealing business-sensitive 

information (compared to reporting by process).

d. Reporting at the facility level

The least detailed option under this section would be to require reporting emissions at the facility

level for all production and transformation processes combined. EPA would anticipate using this 

requirement to supplement a requirement to report emissions at the process level. For example, a 

requirement to report emissions by chemical group at the process level could be supplemented by

a requirement to report emissions by chemical at the facility level. Such an approach would 

retain some of the benefits of chemical-specific reporting (e.g., comparison of emissions 
6

estimates through atmospheric measurements) without linking particular chemicals to particular 

processes. 

2. Levels of Aggregation for Chemicals

a. Reporting by individual (speciated) fluorinated GHG (current subpart L 

requirement)

Subpart L currently requires fluorinated gas producers to report their emissions by chemical. 

For subpart L, information on the identities and characteristics of GHGs is particularly 

important. First, the range of GWPs and atmospheric lifetimes spanned by the fluorinated GHGs 

is quite large. Lifetimes range from a few days (e.g., for several unsaturated fluorocarbons) to 

thousands of years (e.g., for saturated perfluorocarbons), while GWPs range from less than one 

(e.g., for several unsaturated fluorocarbons) to above 20,000 (for SF6). Often, the same 

fluorinated gas production facility may emit fluorinated GHGs at both ends of the GWP and 

lifetime ranges. Knowledge of the GWPs of the chemicals emitted is necessary to distinguish 

between processes emitting many tons of a low-GWP chemical and processes emitting a few 

tons (or kilograms) of a high-GWP chemical. While the CO2-equivalent emissions of both 

processes may be the same, appropriate emission reduction strategies may differ. Knowledge of 

the lifetimes of the chemicals is important to understanding how emissions from different 

processes would fit into policies that focus particularly on short-lived or long-lived GHGs.

3

Second, fluorinated gas producers are a significant emission source for many fluorinated GHGs, 

and for some fluorinated GHGs, they are the only source. This makes them especially important 

in efforts to reconcile atmospheric measurements of fluorinated GHGs with estimates of 

emissions of fluorinated GHGs from all emitting industries. (Most fluorinated GHGs lack 

significant natural sources.) 

Chemical-specific reporting is also consistent with GHG Inventory reporting under the United 

Nations Convention on Climate Change (UNFCCC), which encourages chemical-specific 

reporting. Under the UNFCCC, other countries report chemical-specific emissions from 

comparable fluorinated gas production facilities. For example, in 2011 and previous years, 

Belgium’s GHG inventory reported emissions from “an electrochemical synthesis (electrofluorination) plant, which emits, or has emitted SF6, CF4, C2F6, C3F8, C4F10, C5F12 and C6F14 as 

well as fluorinated greenhouse gases not covered by the Kyoto Protocol (among which CF3SF5, 

C7F16, C8F18 and C8F16O).” From this plant, Belgium reported 2009 emissions of CF4, C4F8, 

C5F12, and C6F14 in tons of each gas.4 France and Italy have also reported chemical-specific 

emissions from their fluorinated gas production facilities.

 

3

For example, the Climate and Clean Air Coalition to Reduce Short-Lived Climate Pollutants Initiative primarily 

focuses on chemicals with atmospheric lifetimes of less than 50 years.

4

Belgium’s Greenhouse Gas Inventory (1990-2009): National Inventory Report submitted under the United Nations 

Framework Convention on Climate Change and the Kyoto Protocol, p. 95, and Table 2(II)s2, Common Reporting 

Format (CRF) Tables submitted by Belgium, April 2011. See 

http://unfccc.int/national_reports/annex_i_ghg_inventories/national_inventories_submissions/items/5888.php
7

b. Reporting by fluorinated GHG group based on chemical structure

One set of options that would retain information on chemical characteristics but not on precise 

chemical identities would be to require reporting of emissions by fluorinated GHG group. Such 

fluorinated GHG groups could be based on chemical structure, GWP, atmospheric lifetime, or 

some combination of these. Whatever the organizing principle, to be useful for policy analysis, 

the groups should meet the following criteria:

1. They should be distinct (i.e., not overlapping);

2. Considered together, they should be comprehensive (i.e., cover all fluorinated 

GHGs);

3. They should track atmospheric lifetime and GWP.

One set of groups that EPA is considering is based on the structure of the chemicals. The groups 

would include:

 Fully fluorinated GHGs. These would include fluorinated GHGs that contain only single 

bonds and in which all available valence locations are filled by fluorine atoms. This 

group would include but is not limited to saturated perfluorocarbons, SF6, NF3, SF5CF3, 

fully fluorinated linear, branched and cyclic alkanes, fully fluorinated ethers, fully

fluorinated tertiary amines, fully fluorinated aminoethers, and perfluoropolyethers. Fully 

fluorinated GHGs generally have lifetimes of over 500 to several thousand years and 

GWPs of 6,500 to 23,900.

 Saturated hydrofluorocarbons. This group would include hydrofluorocarbons that 

contain only single bonds (i.e., hydrofluoroalkanes such as HFC-134a and HFC-23). 

Saturated HFCs generally have lifetimes from 5 to 55 years and GWPs from 650 to 

4,000, but there are exceptions at both extremes (see discussion below).

 Other fluorinated GHGs. This group would include fluorinated GHGs that are neither 

fully fluorinated GHGs nor saturated hydrofluorocarbons. This includes but is not 

limited to hydrofluoro-olefins, fluoroketones, hydrofluoroethers, and 

hydrofluoropolyethers . These GHGs generally have lifetimes of less than 10 years and 

GWPs of less than 1000, but there are some exceptions with higher GWPs and lifetimes.

To ensure that the gas groups are both distinct and comprehensive, the last gas group is designed 

to capture everything not in either of the first two groups. With the exception of HFE-125 and 

 

Because countries are not required to report emissions of fluorinated GHGs outside of the categories defined by 

the UNFCCC, which include HFCs, PFCs, and SF6, this list may not include all of the fluorinated GHGs emitted by the 

plant. Publication of this emissions data may therefore reveal less sensitive data than would be revealed if the list 

were complete. Nevertheless, Belgium’s inclusion of this information in its inventory submission would seem to 

indicate that at least in some cases, emissions of a subset of fluorinated GHGs can be published by species without 

revealing trade secrets. 
8

HFE-134, which have lifetimes of 136 and 26 years respectively, EPA is not aware of any

medium- or long-lived fluorinated GHGs that fall into this group. 

This approach would avoid linking particular chemicals to particular processes, which might 

reveal business-sensitive information. At the same time, reporting by chemical group, defined 

by chemical structure, would provide general information on the chemical and atmospheric 

properties of the emissions because fluorinated GHGs with fairly similar atmospheric lifetimes 

and GWPs would be grouped together. For example, most saturated HFCs whose lifetimes and 

GWPs have been evaluated by the IPCC have lifetimes ranging between 5 and 55 years and 

GWPs ranging between 650 and 4,000 (based on the Second Assessment Report5). It would 

therefore provide useful information for assessing potential emission reduction approaches (e.g., 

if reported at the process level) and for informing policies that distinguish among chemicals 

based on their atmospheric lifetimes and GWPs. It is also similar to the approach of current 

international conventions that address chemicals with impacts on the global atmosphere (e.g., 

UNFCCC, Montreal Protocol).

However, the range of lifetimes and GWPs spanned by each chemical group is still relatively

large, and it becomes larger when outliers are factored in. For example, HFCs include HFC152a (with a lifetime of 1.4 years and a GWP of 140) and HFC-23 (with a lifetime of 270 years 

and a GWP of 11,700). This reduces the usefulness of the data compared to chemical-specific 

reporting or to reporting by other possible chemical groups. 

c. Reporting by fluorinated GHG group based on atmospheric lifetime or GWP

Another option that EPA is considering is to group gases explicitly by atmospheric lifetime or 

GWP. This grouping approach, like that described in Option b, would meet the three criteria 

for gas groupings described above. Table 2 below lists one possible set of groups based on 

atmospheric lifetime. A similar example could be drawn up based on GWP. For the fluorinated 

GHGs whose GWPs are included in Table A-1 of 40 CFR 98, subpart A, EPA could propose to 

add lifetimes to Table A-1 based on the most recent IPCC update of GWPs and lifetimes (e.g., 

the Table 2.14 errata). For fluorinated GHGs whose GWPs and lifetimes were not on Table A-1, 

EPA could propose that reporters would either independently assess the lifetime or GWP of the 

gas or report the gas as unclassified. 

Table 2. Fluorinated GHG Atmospheric Lifetime Groups

Groupings by atmospheric lifetime, years

<1

1-5

5-20

20-60

60-300

 

5 Houghton, J.T., L.G. Meira Filho, B.A. Callander, N. Harris, A. Kattenberg and K. Maskell. Climate Change 

1995: The Science of Climate Change. Contribution of Working Group 1 to the Second Assessment Report of the 

Intergovernmental Panel on Climate Change. (Cambridge University Press, 1996).
9

>300

Under this approach, the ranges of atmospheric lifetimes and GWPs would be considerably

lower than under Option b, increasing the usefulness of the data compared to Option b. 

However, this option would require facilities to know the lifetime of each chemical to report it. 

Although lifetimes have been estimated for the fluorinated GHGs listed on Table A-1 (and could 

therefore be easily added to this table by EPA), they have not necessarily been estimated for 

fluorinated GHGs that are not on Table A-1. (Atmospheric lifetimes are easier to assess than 

GWPs, however.)

Hybrids of the two grouping options (chemical structure and atmospheric lifetime or GWP)

could partially address the drawbacks of each (e.g., by breaking saturated HFCs into two or more 

groups based on lifetime), but this would increase the complexity of the rule. 

d. Reporting emissions in terms of CO2e across all fluorinated GHGs

EPA is also considering requiring reporting of fluorinated GHG emissions in terms of CO2e

across all fluorinated GHGs. EPA would anticipate combining this option with another option 

(e.g., process emissions could be reported in CO2e while facility-level emissions could be 

reported by chemical). If CO2e emissions were reported at the process level, this approach 

would allow ranking of processes in terms of their GWP-weighted emissions. However, unlike 

reporting by chemical group, it would not allow EPA to distinguish between processes that emit 

large quantities of low-GWP chemicals and small quantities of high-GWP chemicals. Similarly, 

it would not inform policies that distinguish among chemicals based on their atmospheric 

lifetimes and GWPs. Finally, for fluorinated GHGs that are not on Table A-1, this approach 

would require facilities to know or estimate GWPs or to use default GWPs (see the discussion 

below) .

3. Converting fluorinated GHG emissions into CO2e

To convert non-CO2 emissions into CO2e, the EPA generally requires facilities to use Equation 

A-1 of subpart A, which multiplies the mass of each chemical by the GWP for that chemical in 

Table A-1. For fluorinated GHGs that do not have a GWP listed in Table A-1, EPA is 

considering an option under which facilities would either use a default GWP or use their best 

estimate of the GWP, based on the information described in 40 CFR 98.123(c)(1)(vi)(A)(3) . The 

default GWP used would depend on the type of fluorinated GHG. For fully fluorinated GHGs,6

the default GWP would be 10,000, which is based on the average GWP of the fully fluorinated 

GHGs on Table A-1. For other fluorinated GHGs, the default GWP would be 2,000, which is 

based on the average GWP of the other fluorinated GHGs on Table A-1. EPA would propose to 

 

6

This gas grouping is discussed above. The definition of “fully fluorinated GHGs” is “fluorinated GHGs that contain 

only single bonds and in which all available valence locations are filled by fluorine atoms. This includes but is not 

limited to saturated perfluorocarbons, SF6, NF3, SF5CF3, fully fluorinated linear, branched and cyclic alkanes, fully 

fluorinated ethers, fully fluorinated tertiary amines, fully fluorinated aminoethers, and perfluoropolyethers.”
10

distinguish between fully fluorinated GHGs and other fluorinated GHGs because the former have 

significantly longer lifetimes and higher GWPs than the latter.

Facilities using best estimate GWPs would also be required to report those GWPs to EPA along 

with the data and analysis that were used to develop the GWPs. This would enable EPA to 

verify the GWPs and to consider them for inclusion on Table A-1.

The default GWPs would be an option for facilities that either do not know the GWPs of the 

fluorinated GHGs that they emit or do not wish to report best-estimate GWPs for one or more 

chemicals because this would involve disclosure of the identities of the chemicals. The default 

of 2000 (for fluorinated GHGs other than fully fluorinated GHGs) would be the same as that 

used by facilities to calculate whether they must use stack testing to establish an emission factor 

for a vent that emits one or more fluorinated GHGs that do not have GWPs on Table A-1. Both 

the 2000 and 10,000 default GWPs are intended to represent averages across their respective gas 

groups; they are not conservative. EPA expects that this would generally result in unbiased 

estimates of facility-wide CO2e emissions that include fluorinated GHGs without GWPs on 

Table A-1; however, some facilities might choose to use the default rather than their own bestestimate if that estimate was higher than the default. In this case, facility-wide CO2e emissions 

would be underestimated, and EPA might never receive the information necessary to update 

Table A-1 to correct the underestimate. Other options include making the defaults more 

conservative (i.e., higher numerically) to encourage facilities to estimate and report their own 

GWPs, and requiring facilities to report speciated emissions of fluorinated GHGs (and estimated 

GWPs, if available) that are not on Table A-1 and are emitted in significant quantities (e.g., 1 ton 

or more for each fully fluorinated GHG and 5 tons or more for each other fluorinated GHG, 

which would be expected to equate to approximately 10,000 mtCO2e in either case).

IV. References

1. 77 FR 1434. January 10, 2012. Proposed Confidentiality Determinations for Data Elements 

under the Mandatory Reporting of Greenhouse Gases Rule.

2. Muffat, Jeffry C., to EPA Docket No. EPA-HQOAR-2011-028. Public comment letter to 

EPA’s Proposed Confidentiality Determinations for Data Elements under the Mandatory

Reporting of Greenhouse Gases Rule. EPA-HQ-OAR-2011-0028-0018. Dated March 12, 

2012.

3. Mascarenhas, Brendan, to EPA Docket No. EPA-HQOAR-2011-028. Public comment letter 

to EPA’s Proposed Confidentiality Determinations for Data Elements under the Mandatory

Reporting of Greenhouse Gases Rule. EPA-HQ-OAR-2011-0028-0017. Dated March 12, 

2012.