SUPPLEMENTARY INFORMATION:

I. General Information

A. What is today's notice about?

• The EPA is making available for public comment estimated GWPs for the eight fluorinated heat transfer fluids (HTFs) listed in Table 1 of this notice as well as data and analysis submitted in support of those GWPs.
• The EPA is also making available for public comment cited GWPs for the 35 fluorinated GHGs and fluorinated HTFs listed in Table 2 of this notice. The EPA does not currently possess supporting data and analysis for these GWPs.
• Both sets of chemicals and their GWPs are being considered for addition to Table A-1 to subpart A of part 98, the compendium of GWPs used to convert tons of chemical into tons of carbon dioxide equivalent (CO₂ e) under the Greenhouse Gas Reporting Program.

B. How does this notice relate to the forthcoming proposed rule titled “2013 Revisions to the Greenhouse Gas Reporting Rule and Proposed Confidentiality Determinations for New or Substantially Revised Data Elements”?

In the proposed rule signed March 8, 2013, titled “2013 Revisions to the Greenhouse Gas Reporting Rule and Proposed Confidentiality Determinations for New or Substantially Revised Data Elements” (hereinafter referred to as the “2013 Technical Corrections Proposed Rule”), the EPA is proposing to amend subpart A, General Provisions, to propose GWPs for certain fluorinated greenhouse gases not currently listed in Table A-1 to subpart A. This notice requests comment on GWPs for fluorinated GHGs and fluorinated HTFs for which documented GWPs were not available in time for inclusion in the 2013 Technical Corrections Proposed Rule. The comments submitted in response to this notice are intended to inform a potential future rulemaking to amend Table A-1 to subpart A to add the GWPs of some or all of the fluorinated GHGs and fluorinated HTFs listed in this notice.

C. Where can I get the information?

All of the information can be obtained through the Docket and at http://www.regulations.gov (see ADDRESSES section above for docket contact information).

D. What is the EPA taking comment on and what supporting documentation do I need to include in my comments?

The EPA requests comment on topics including but not limited to the following:

• For the fluorinated HTFs in Table 1 of this notice, the reliability, including the likely accuracy and precision, of the GWPs listed in Table 1 given the data and analysis submitted in support of them, and
• The completeness, quality, and transparency of the data and analysis submitted in support of the GWPs in Table 1 of this notice.
• For the fluorinated GHGs and HTFs in Table 2 of this notice, the reliability, including the likely accuracy and precision, of the GWPs listed, and
• The accuracy of the chemical names and formulas listed.

For the fluorinated HTFs in Table 1 of this notice, the EPA is specifically seeking comment on the extent to which the supporting data and analysis includes the following:

• Data and analysis related to the low-pressure gas phase infrared absorption spectrum of the fluorinated GHG.
• Data and analysis related to the estimated atmospheric lifetime of the fluorinated GHG (reaction mechanisms and rates, including e.g., photolysis and reaction with atmospheric components such as OH, O₃, CO, and water), including descriptions of the measurements or modeling.
• The radiative transfer analysis that integrates the lifetime and infrared absorption spectrum data to calculate the GWP.
• Any published or unpublished studies of the GWP of the gas.

Where quantitative structure-activity relationship (QSAR) models have been used, the EPA is seeking comment on the extent to which the data and ( print page 20634) analysis include information documenting the level of accuracy of the QSAR-derived GWP, including:

• Information on how the structure of the “target” fluorinated GHG is similar to the structures of the fluorinated GHGs used to model the radiative forcing and/or reaction rate of the “target” fluorinated GHG.
• Information on the quality (i.e., accuracy and precision) and quantity of the measurements of the radiative forcings and/or reaction rates of the fluorinated GHGs used to model these parameters for the “target” fluorinated GHG.
• Estimated uncertainties of the modeled forcings and/or reaction rates.
• Descriptions and results of any efforts to validate the QSAR model(s).

E. What should I consider as I prepare my comments for EPA?

• Explain your views as clearly as possible.
• Describe any assumptions that you used.
• Provide any technical information or data you used that support your views.
• Provide specific examples to illustrate your concerns.
• Offer alternatives.
• Make sure to submit your comments by the comment period deadline identified.
• To ensure proper receipt by EPA, identify the appropriate docket identification number in the subject line on the first page of your response. It would also be helpful if you provided the name, date, andFederal Register citation related to your comments.

F. Submitting Confidential Business Information (CBI)

Do not submit information you are claiming as CBI to EPA through http://www.regulations.gov or email. Clearly mark the part of the information that you claim to be CBI. Information so marked will not be disclosed except in accordance with procedures set forth in 40 CFR part 2. For CBI information in a disk or CD-ROM that you mail to EPA, mark the outside of the disk or CD-ROM as CBI and then identify electronically within the disk or CD-ROM the specific information that is claimed as CBI. In addition to one complete version of the comment that includes information claimed as CBI, a copy of the comment that does not contain the information claimed as CBI must be submitted for inclusion in the public docket.

II. Background

Table A-1 to subpart A of 40 CFR part 98 (“Table A-1”) is a compendium of GWP values of certain GHGs that are required to be reported under one or more subparts of the Greenhouse Gas Reporting rule (“Part 98”). These GWPs are used to convert tons of chemical into tons of CO₂ -equivalent for purposes of various calculations and reporting under the rule. As acknowledged in the Federal Register notice for the final Part 98 (74 FR 56348, October 30, 2009), it is the EPA's intent to periodically update Table A-1 as GWPs are evaluated or re-evaluated by the scientific community. This will provide a more accurate and complete account of the atmospheric impacts of GHG emissions and supplies.

Table A-1 of Part 98 currently includes 10 fluorinated HTFs of which EPA is aware, but there are a number that it does not include. Of the 42 fluorinated HTFs listed in this notice (none of which is on Table A-1 of Part 98), electronics facilities reported emissions of 17 under the Greenhouse Gas Reporting Program (GHGRP). Electronics facilities reported use of another four in a 2009 industry survey by the International SEMATECH Manufacturing Initiative (Technology Transfer #09065014A-TR). Other HTFs (those with vapor pressures below 1 mm Hg at 25 degrees C) may be reported for the first time this year because of an expanded definition of fluorinated HTF that went into effect in 2012. Several of the fluorinated HTFs in this notice are fully fluorinated. Fully fluorinated compounds are likely to have long atmospheric lifetimes and high GWPs.^[1]

There are two primary suppliers of fluorinated HTFs used in the United States: 3M Company (3M) and Solvay. After evaluating the reports submitted under subpart I, the EPA contacted 3M and Solvay and requested any data and information they had regarding the GWPs of the fluorinated HTFs that they supplied.

3M responded with estimated GWPs and supporting data and analysis for eight fluorinated HTFs collectively composed of nine fluorinated compounds. (One of the HTFs, FC-77, is a blend of two fluorinated compounds.) For one of the fluorinated compounds, C₈ F₁₈, the EPA is proposing a GWP in the 2013 Technical Corrections Proposed Rule. Thus, the EPA is not requesting comment on the GWP of C₈ F₁₈ through this action. However, the EPA is requesting comment on the GWPs and supporting data and analysis for the other eight compounds, which are listed in Table 1 of this notice. These compounds (along with the 3M HTFs already included on Table A-1 of Part 98) account for most of the emissions of 3M-supplied HTFs reported to EPA under subpart I to date (i.e., in 2012).

Solvay indicated that it generally did not possess data and analysis to support estimated GWPs for the Solvay-supplied HTFs that are not already on Table A-1 of Part 98.^[2] Table 2 of this notice therefore includes all of the Solvay-supplied fluorinated HTFs of which EPA is aware and which are not already included on Table A-1. It also includes some 3M-supplied fluorinated HTFs (and one fluorinated GHG used as a chamber cleaning gas) for whose estimated GWPs 3M did not submit supporting data and analysis. 3M indicates that some of these HTFs are no longer produced.

For several of the fluorinated HTFs (and for the fluorinated GHG) in Table 2 of this notice, approximate GWPs have been presented or published (e.g., in presentations to the EPA or in material safety data sheets (MSDSs)) without accompanying explanation or documentation of how those GWPs have been developed. For a large subset of these fully fluorinated chemicals, GWPs of 10,000 were identified in a presentation given by 3M to EPA. For some of these chemicals, different GWPs were identified in other sources, such as MSDSs issued by 3M or Solvay. These are the GWPs that are included in Table 2. The EPA does not intend to add the cited GWPs for these compounds to Table A-1 of Part 98 without supporting data and analysis. We are therefore continuing to assemble and evaluate information regarding the GWPs for the compounds in Table 2 of this notice. We request comment on these GWPs and on the accuracy of the listed chemical names and formulas for the compounds.

III. GWP Values on Which EPA is Seeking Comment ( print page 20635)

IV. Summary of EPA Assessment of Submitted GWPs and the Data and Analysis Supporting Them

The EPA completed a review of the GWPs listed in Table 1 of this notice and the data and analysis submitted in support of them. That assessment is available in the docket, together with the submitted data and analyses. In general, we found that the data and methods used to estimate the GWPs were reasonable and that the GWPs were consistent with what would be expected for compounds of the types analyzed. However, there were some limitations to the data and analysis. First, in some cases the transparency of the data and analysis were limited because some of the reports containing the detailed background information were not available for review in time for this notice. Second, some of the data were of uncertain quality because they were based on an unpublished master's thesis. Third, because some of the analyses were performed in the early 1990s, some of the models used to estimate lifetimes or radiative efficiencies were out of date. Fourth, in one case (PTAA), radiative efficiency estimates were based on a quantitative structural activity relationship (QSAR) of uncertain predictive ability. Fifth, the atmospheric lifetime for one of the short-lived compounds (HFE-7300) was estimated based on an atmospheric lifetime for methane that is lower than the currently accepted lifetime, resulting in an underestimated lifetimes for that compound. Finally, for the six long-lived compounds, experimental limitations prevented 3M or its researchers from establishing more than minimum atmospheric lifetimes, and the GWPs based on these lifetimes are therefore also minimums.

Overall, we do not expect that these limitations resulted in large errors in the resulting GWPs; and with the exception of the errors attributable to the last two issues (related to atmospheric lifetimes), we expect that these are random rather than systematic errors. To address the last two issues, we examined the sensitivity of the GWPs of the compounds to atmospheric lifetime. In general, 100-year GWPs for very long-lived compounds are relatively insensitive to increases in assumed atmospheric lifetime, and our analysis confirmed this. However, the 100-year GWPs for the short-lived compounds are sensitive to increases in the assumed atmospheric lifetime. For example, updating the atmospheric lifetime for HFE-7300 based on the currently accepted atmospheric lifetime of methane increases the estimated GWP of HFE-7300 by 10 percent.