Document ID: EPA-HQ-OAR-2010-0605-0001
Agency: epa
Document Type: Proposed Rule
Title: Air Quality: Revision to Definition of Volatile Organic Compounds- Exclusion of trans-1,3,3,3- tetrafluoropropene and 2,3,3,3- tetrafluoropropene
Posted Date: 2011-10-17T04:00Z

[Federal Register Volume 76, Number 200 (Monday, October 17, 2011)]
[Proposed Rules]
[Pages 64059-64065]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2011-26768]

[[Page 64059]]

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 51

[EPA-HQ-OAR-2010-0605; FRL-9480-4]
RIN 2060-AQ38

Air Quality: Revision to Definition of Volatile Organic 
Compounds--Exclusion of trans-1,3,3,3-tetrafluoropropene and 2,3,3,3-
tetrafluoropropene

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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SUMMARY: The EPA is proposing to revise the agency's definition of 
volatile organic compounds (VOCs) for purposes of preparing state 
implementation plans (SIPs) to attain the national ambient air quality 
standards (NAAQS) for ozone under Title I of the Clean Air Act (CAA). 
This proposed revision would add 2,3,3,3-tetrafluoropropene (also known 
as HFO-1234yf) and trans-1,3,3,3-tetrafluoropropene (also known as HFO-
1234ze) to the list of compounds excluded from the definition of VOC on 
the basis that these compounds make a negligible contribution to 
tropospheric ozone formation.

DATES: Comments must be received on or before November 16, 2011.
    Public Hearing: If anyone contacts us requesting to speak at a 
public hearing on or before November 1, 2011, we will hold a public 
hearing. Additional information about the hearing would be published in 
a subsequent Federal Register notice.

ADDRESSES: Submit your comments, identified by Docket ID No. EPA-HQ-
OAR-2010-0605, by one of the following methods:
     http://www.regulations.gov. Follow the on-line 
instructions for submitting comments.
     E-mail: a-and-r-Docket@epamail.epa.gov, Attention Docket 
ID No. EPA-HQ-OAR-2010-0605.
     Fax: 202-566-1541, Attention Docket ID No. EPA-HQ-OAR-
2010-0605.
     Mail: Docket ID No. EPA-HQ-OAR-2010-0605, Environmental 
Protection Agency, Mailcode: 6102T, 1200 Pennsylvania Ave., NW., 
Washington, DC 20460.
     Hand Delivery: EPA Docket Center, U.S. Environmental 
Protection Agency, 1301 Constitution Avenue, NW., Room: 3334, Mail 
Code: 6102T, Washington, DC 20460, Attention Docket ID No. EPA-HQ-OAR-
2010-0605. Such deliveries are only accepted during the Docket's normal 
hours of operation, and special arrangements should be made for 
deliveries of boxed information.
    Instructions: Direct your comments to Docket ID No. EPA-HQ-OAR-
2010-0605. The EPA's policy is that all comments received will be 
included in the public docket without change and may be made available 
online at http://www.regulations.gov, including any personal 
information provided, unless the comment includes information claimed 
to be Confidential Business Information (CBI) or other information 
whose disclosure is restricted by statute. Do not submit information 
that you consider to be CBI or otherwise protected through http://www.regulations.gov, or e-mail. The http://www.regulations.gov Web site 
is an ``anonymous access'' system, which means the EPA will not know 
your identity or contact information unless you provide it in the body 
of your comment. If you send an e-mail comment directly to the EPA 
without going through http://www.regulations.gov, your e-mail address 
will be automatically captured and included as part of the comment that 
is placed in the public docket and made available on the Internet. If 
you submit an electronic comment, the EPA recommends that you include 
your name and other contact information in the body of your comment and 
with any disk or CD-ROM you submit. If the EPA cannot read your comment 
due to technical difficulties and cannot contact you for clarification, 
the EPA may not be able to consider your comment. Electronic files 
should avoid the use of special characters, any form of encryption, and 
be free of any defects or viruses. For additional information about the 
EPA's public docket, visit the EPA Docket Center homepage at http://www.epa.gov/epahome/dockets.htm.
    Docket: All documents in the docket are listed in the http://www.regulations.gov index. Although listed in the index, some 
information is not publicly available, i.e., CBI or other information 
whose disclosure is restricted by statute. Certain other material, such 
as copyrighted material, will be publicly available only in hard copy. 
Publicly available docket materials are available either electronically 
in http://www.regulations.gov or in hard copy at the EPA, EPA/DC, EPA 
West, Room 3334, 1301 Constitution Ave., NW., Washington, DC. The 
Public Reading Room is open from 8:30 a.m. to 4:30 p.m., Monday through 
Friday, excluding legal holidays. The telephone number for the Public 
Reading Room is (202) 566-1744, and the telephone number for the EPA 
Docket is (202) 566-1742.

FOR FURTHER INFORMATION CONTACT: David Sanders, Office of Air Quality 
Planning and Standards, Air Quality Policy Division, Mail Code C539-01, 
Research Triangle Park, NC 27711; telephone: (919) 541-3356; fax 
number: (919) 541-0824; e-mail address: sanders.dave@epa.gov.

SUPPLEMENTARY INFORMATION: 

I. General Information

A. Does this action apply to me?

    Entities potentially affected by this proposed rule include, but 
are not necessarily limited to, states (typically state air pollution 
control agencies) that control VOCs, and industries involved in the 
manufacture or use of refrigerants, aerosol propellants, and blowing 
agents for insulating foams.

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           Industry group                           SIC \a\                               NAICS \b\
----------------------------------------------------------------------------------------------------------------
Refrigerants.......................  2869, 3585...........................  238220, 336111, 336391.
Aerosol propellants................  2869.................................  325998.
Blowing agents.....................  2869, 3086...........................  326140, 326150.
----------------------------------------------------------------------------------------------------------------
\a\ Standard Industrial Classification.
\b\ North American Industry Classification System.

    This proposed rule is applicable to all manufacturers, 
distributors, and users of these chemical compounds. The use of these 
compounds is subject to restrictions under the CAA and the Toxic 
Substances Control Act (TSCA). Specifically, the use of these compounds 
as aerosol propellants, blowing agents, or refrigerants, or any other 
use in which they would substitute for chlorofluorocarbons, 
hydrochlorofluorocarbons, or their

[[Page 64060]]

substitutes, is subject to restrictions under the Significant New 
Alternatives Policy (SNAP) program (CAA Sec.  612; 40 CFR 82 subpart 
G). The SNAP program has issued a final approval for HFO-1234yf as a 
substitute for use in the motor vehicle air conditioning end-use as a 
replacement for ozone depleting substances (76 FR 17488, March 29, 
2011), and final approvals for HFO-1234ze as a suitable foam and 
refrigerant substitute and as a propellant (74 FR 50129, September 30, 
2009; 75 FR 34017, June 16, 2010). Furthermore, HFO-1234yf is subject 
to a Significant New Use Rule (SNUR) under TSCA. (75 FR 65987, October 
27, 2010). The implications of these other regulations are discussed in 
more detail in Section III.

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

    Submitting CBI: Do not submit this information to the EPA through 
http://www.regulations.gov or e-mail. Clearly mark the part or all of 
the information that you claim to be CBI. For CBI information in a disk 
or CD-ROM that you mail to the 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. 
Information so marked will not be disclosed except in accordance with 
procedures set forth in 40 CFR part 2.

C. How can I find information about a possible public hearing?

    Public Hearing: To request a public hearing or information 
pertaining to a public hearing on this document, contact Ms. Pamela S. 
Long, Air Quality Policy Division, Mail code C504-01, U.S. 
Environmental Protection Agency, Research Triangle Park, NC 27711, 
telephone (919) 541-0641, facsimile number (919) 541-5509, e-mail 
address: long.pam@epa.gov.

D. How is this preamble organized?

    The information presented in this preamble is organized as follows:

I. General Information
    A. Does this action apply to me?
    B. What should I consider as I prepare my comments for the EPA?
    C. How can I find information about a possible public hearing?
    D. How is this preamble organized?
II. Background
    A. Petition To List HFO-1234yf
    B. Petition To list HFO-1234ze
III. The EPA's Proposed Responses to the Petitions
    A. Contribution to Tropospheric Ozone
    B. Likelihood of Risk to Human Health or the Environment
    C. Conclusions
IV. Proposed Action
V. Statutory and Executive Order Reviews
    A. Executive Order 12866: Regulatory Planning and Executive 
Order 13563: Improving Regulation and Regulatory Review
    B. Paperwork Reduction Act
    C. Regulatory Flexibility Act
    D. Unfunded Mandates Reform Act
    E. Executive Order 13132: Federalism
    F. Executive Order 13175: Consultation and Coordination With 
Indian Tribal Governments
    G. Executive Order 13045: Protection of Children From 
Environmental Health and Safety Risks
    H. Executive Order 13211: Actions That Significantly Affect 
Energy Supply, Distribution, or Use
    I. National Technology Transfer and Advancement Act
    J. Executive Order 12898: Federal Actions To Address 
Environmental Justice in Minority Populations and Low-Income 
Populations.

II. Background

    Tropospheric ozone, commonly known as smog, is formed when VOCs and 
nitrogen oxides (NOX) react in the atmosphere in the 
presence of sunlight. Because of the harmful health effects of ozone, 
the EPA and state governments limit the amount of VOCs that can be 
released into the atmosphere. The VOCs are those organic compounds of 
carbon which form ozone through atmospheric photochemical reactions. 
Different VOCs have different levels of reactivity--that is, they do 
not react to form ozone at the same speed or do not form ozone to the 
same extent. Some VOCs react slowly, or form less ozone; therefore, 
changes in their emissions have limited effects on local or regional 
ozone pollution episodes. It has been the EPA's policy that organic 
compounds with a negligible level of reactivity should be excluded from 
the regulatory definition of VOC so as to focus VOC control efforts on 
compounds that do significantly increase ozone concentrations. The EPA 
also believes that exempting such compounds creates an incentive for 
industry to use negligibly reactive compounds in place of more highly 
reactive compounds that are regulated as VOCs. The EPA lists these 
negligibly reactive compounds in its regulations (at 40 CFR 51.100(s)) 
and excludes them from the definition of VOC.
    The CAA requires the regulation of VOCs for various purposes. 
Section 302(s) of the CAA specifies that the EPA has the authority to 
define the meaning of ``VOC,'' and hence what compounds shall be 
treated as VOCs for regulatory purposes. The policy of excluding 
negligibly reactive compounds from the VOC definition was first laid 
out in the ``Recommended Policy on Control of Volatile Organic 
Compounds'' (42 FR 35314, July 8, 1977) and was supplemented most 
recently with the ``Interim Guidance on Control of Volatile Organic 
Compounds in Ozone State Implementation Plans'' (Interim Guidance) (70 
FR 54046, September 13, 2005). The EPA uses the reactivity of ethane as 
the threshold for determining whether a compound has negligible 
reactivity. Compounds that are less reactive than, or equally reactive 
to, ethane under certain assumed conditions may be deemed negligibly 
reactive and therefore suitable for exemption from the regulatory 
definition of VOC. Compounds that are more reactive than ethane 
continue to be considered VOCs for regulatory purposes and therefore 
subject to control requirements. The selection of ethane as the 
threshold compound was based on a series of smog chamber experiments 
that underlay the 1977 policy.
    The EPA has used three different metrics to compare the reactivity 
of a specific compound to that of ethane: (i) the reaction rate 
constant (known as kOH) with the hydroxyl radical (OH); (ii) 
the maximum incremental reactivities (MIR) of ethane and the compound 
in question expressed on a reactivity per unit mass basis; and (iii) 
the MIR of ethane and the compound in question expressed on a 
reactivity per mole basis. Differences between these three metrics are 
discussed below.
    The kOH is the reaction rate constant of the compound 
with the OH radical in the air. This reaction is typically the first 
step in a series of chemical reactions by which a compound breaks down 
in the air and participates in the ozone-forming process. If this step 
is slow, the compound will likely not form ozone at a very fast rate. 
The kOH values have long been used by the EPA as a measure 
of photochemical reactivity and ozone-forming activity, and they have 
been the basis for most of the EPA's previous exemptions of negligibly 
reactive compounds from the regulatory definition of VOC. The 
kOH metric is inherently a molar comparison, i.e., it 
measures the rate at which molecules react.
    The MIR values, both by mole and by mass, are a more recently 
developed measure of photochemical reactivity derived from a computer-
based photochemical model. This

[[Page 64061]]

measurement considers the complete ozone forming activity of a 
compound, not merely the first reaction step. Further explanation of 
the MIR metric can be found in: W. P. L. Carter, ``Development of Ozone 
Reactivity Scales for Volatile Organic Compositions,'' Journal of the 
Air & Waste Management Association, Vol. 44, 881-899, July 1994.
    The MIR values for compounds are typically expressed as grams of 
ozone formed per gram of VOC (mass basis), but may also be expressed as 
grams of ozone formed per mole of VOC (molar basis). For comparing the 
reactivities of two compounds, using the molar MIR values considers an 
equal number of molecules of the two compounds. Alternatively, using 
the mass MIR values compares an equal mass of the two compounds, which 
will involve different numbers of molecules, depending on the relative 
molecular weights. The molar MIR comparison is consistent with the 
original smog chamber experiments that underlie the original selection 
of ethane as the threshold compound and compared equal molar 
concentrations of individual VOCs. It is also consistent with previous 
reactivity determinations based on inherently molar kOH 
values. By contrast, the mass MIR comparison is more consistent with 
how MIR values and other reactivity metrics have been applied in 
reactivity-based emission limits, such as the national VOC emissions 
standards for aerosol coatings (73 FR 15604). Many other VOC 
regulations contain limits based upon a weight of VOC per volume of 
product, such as the EPA's regulations for limiting VOC emissions from 
architectural and industrial maintenance coatings (65 FR 7736). 
However, the fact that regulations are structured to measure VOC 
content by weight for ease of implementation and enforcement does not 
necessarily control whether VOC exemption decisions should be made on a 
weight basis as well.
    The choice of the molar basis versus the mass basis for the ethane 
comparison can be significant. Given the relatively low molecular 
weight of ethane, use of the mass basis tends to result in more VOCs 
being classified as ``negligibly reactive'' than in the case of the 
molar basis. In some cases, a compound might be considered less 
reactive than ethane and eligible for VOC exemption under the mass 
basis but not under the molar basis. The compounds considered in this 
proposal, HFO-1234yf and HFO-1234ze, fall into this category, where the 
molar MIR value is greater than that of ethane, but the mass MIR value 
is equal to or less than that of ethane. However, for both compounds, 
both MIR values fall in the lower portion of the very wide range of VOC 
reactivities.
    The EPA has considered the choice between a molar or mass basis for 
the comparison to ethane in past rulemakings and guidance. Most 
recently, in the Interim Guidance, the EPA stated:

    [A] comparison to ethane on a mass basis strikes the right 
balance between a threshold that is low enough to capture compounds 
that significantly affect ozone concentrations and a threshold that 
is high enough to exempt some compounds that may usefully substitute 
for more highly reactive compounds.
    When reviewing compounds that have been suggested for VOC-exempt 
status, EPA will continue to compare them to ethane using 
kOH expressed on a molar basis and MIR values expressed 
on a mass basis.

    In this action, the EPA is proposing to exempt these compounds 
using the comparison to ethane on the mass basis MIR value, because MIR 
values are available for these compounds and the EPA believes that this 
comparison is appropriate.
    The EPA's 2005 Interim Guidance also notes that concerns have 
sometimes been raised about the potential impact of a VOC exemption on 
environmental endpoints other than ozone concentrations, including fine 
particle formation, air toxics exposures, stratospheric ozone 
depletion, and climate change. The EPA has recognized, however, that 
there are existing regulatory and non-regulatory programs that are 
specifically designed to address these issues, and the agency continues 
to believe that the impacts of VOC exemptions on environmental 
endpoints other than ozone formation will be adequately addressed by 
these programs. The VOC exemption policy is intended to facilitate 
attainment of the ozone NAAQS, and questions have been raised as to 
whether the agency has authority to use its VOC exemption policy to 
address concerns that are unrelated to ground-level ozone. Thus, in 
general, VOC exemption decisions will continue to be based solely on 
consideration of a compound's contribution to ozone formation. However, 
if the agency determines that a particular VOC exemption is likely to 
result in a significant increase in the use of a compound and that the 
increased use would pose a significant risk to human health or the 
environment that would not be addressed adequately by existing programs 
or policies, the EPA reserves the right to exercise its judgment in 
deciding whether to grant an exemption.
    In this case, the agency has examined available information on the 
risks to human health and the environment and applicability of other 
regulatory programs; that information for the two compounds considered 
here is discussed further in Section III.

A. Petition to List HFO-1234yf

    Honeywell, Inc. submitted a petition to the EPA on June 29, 2009, 
requesting that HFO-1234yf (CAS 754-12-1) be exempted from VOC control 
based on its low reactivity relative to ethane. The petitioner 
indicated that HFO-1234yf may be used as a refrigerant for 
refrigeration and air-conditioning. Honeywell also indicated that it 
expects HFO-1234yf to be widely used as a replacement for HFC-134a in 
motor vehicle air-conditioners (MVAC), and that HFO-1234yf has been 
specifically developed for this purpose. Honeywell argues that as a 
replacement for use in motor vehicle air conditioners there will be an 
environmental advantage in that the global warming potential (GWP) of 
HFO-1234yf is 4, which is substantially lower than the GWP for HFC-134a 
(100-year GWP = 1430) which HFO-1234yf is designed to replace. 
Honeywell submitted several documents, including several peer-reviewed 
journal articles, to support this petition that have been added to the 
docket for this action.

B. Petition to List HFO-1234ze

    Honeywell, Inc. also submitted a petition to the EPA on December 2, 
2009, requesting that HFO-1234ze (CAS 29118-24-9) be exempted from VOC 
control based on its low reactivity relative to ethane. The petitioner 
indicated that HFO-1234ze may be used in a variety of applications 
including as a refrigerant, an aerosol propellant, and a blowing agent 
for insulating foam. Honeywell submitted several documents, including 
several peer-reviewed journal articles, to support its petition, all of 
which have been added to the docket for this action.

III. The EPA's Proposed Responses to the Petitions

    Consistent with the Interim Guidance, the EPA's proposed responses 
to the petitions are based on a consideration of the contribution that 
each chemical makes to tropospheric ozone formation based on a 
comparison of reactivity metrics, and our assessment that existing 
programs or policies already adequately address the possibility that 
granting each petition would pose a significant risk to human health or 
the environment. We also believe that the

[[Page 64062]]

much lower global warming potential of HFO-1234yf compared to the 
compound HFC-134a for which it will substitute, as described in Section 
III.B, is an additional reason to approve the HFO-1234yf petition in 
particular, given that applying the Interim Guidance itself supports 
such approval. Information on these topics is given below.

A. Contribution to Tropospheric Ozone

    Table 1 presents three reactivity metrics for ethane (the benchmark 
compound) and for HFO-1234yf and HFO-1234ze which are proposed for 
exemption from the VOC definition in this proposed rule.

                           Table 1--Reactivities of Ethane, HFO-1234ze and HFO-1234yf
----------------------------------------------------------------------------------------------------------------
                                                                                MIR  (g O3/mole   MIR (g O3/gram
                  Compound                       kOH  (cm\3\/molecule-sec)           VOC)              VOC)
----------------------------------------------------------------------------------------------------------------
Ethane......................................  2.4 x 10-\13\..................              8.4             0.28
HFO-1234yf..................................  10.5 x 10-\13\.................             31.92            0.28
HFO-1234ze..................................  9.25 x 10-\13\.................             11.2             0.098
----------------------------------------------------------------------------------------------------------------
Notes:
1. kOH value for ethane is from: R. Atkinson, D. L. Baulch, R. A. Cox, J. N. Crowley, R. F. Hampson, Jr., R. G.
  Hynes, M. E. Jenkin, J. A. Kerr, M. J. Rossi, and J. Troe (2004), Summary of evaluated kinetic and
  photochemical data for atmospheric chemistry.
2. kOH value for HFO-1234ze is from: R. Sondergaard, O. J. Nielsen, M. D. Hurley, T. J. Wallington, and R.
  Singh, ``Atmospheric chemistry of trans-CF3CH=CHF: kinetics of the gas-phase reactions with Cl atoms, OH
  radicals, and O3.'' Chemical Physics Letters, 443 (2007) 199-204.
3. kOH value for HFO-1234yf is from: O.J. Nielson, M.S. Javadi, M.P. Sulbaek Anderson, M.D. Hurley, T.J.
  Wallington, R. Singh, ``Atmospheric Chemistry of CF3CF=CH2: kinetics and mechanisms of gas-phase reactions
  with Cl atoms, OH Radicals, and O3,'' Chemical Physical Letters, 439 (2007) 18-22.
4. Maximum incremental reactivity or MIR (g O3/g VOC) values of ethane, HFO-1234ze and HFO-1234yf are from:
  William P. L. Carter, ``Development of the SAPRC-07 chemical mechanism and updated ozone reactivity scales''
  (updated 1/27/10). http://www.engr.ucr.edu/carter/SAPRC/saprc07.pdf.
5. Molar MIR (g O3/mole VOC) values were calculated from the mass MIR (g O3/g VOC) values by determining the
  number of moles per gram of the relevant organic compound.

    From the data in Table 1, it can be seen that HFO-1234yf has a 
higher kOH value than ethane, meaning that it initially 
reacts more quickly in the atmosphere than ethane. A molecule of HFO-
1234yf is also more reactive than a molecule of ethane, as shown by the 
molar MIR (g O3/mole VOC) values, because equal numbers of 
moles have equal numbers of molecules. However, a gram of HFO-1234yf 
has the same reactivity as a gram of ethane. This is because HFO-1234yf 
has a molecular weight (114) that is more than three times that of 
ethane (molecular weight 30), and thus requires less than a third the 
number of molecules of HFO-1234yf per gram than the number of molecules 
of ethane per gram.
    From the data in Table 1, it also can be seen that HFO-1234ze has a 
higher kOH value than ethane, meaning that it initially 
reacts more quickly in the atmosphere than ethane. A molecule of HFO-
1234ze is also more reactive than a molecule of ethane, as shown by the 
molar MIR (g O3/mole VOC) values, since equal numbers of 
moles have equal numbers of molecules. However, a gram of HFO-1234ze is 
less reactive, or creates less ozone on the day of its emission to the 
atmosphere, than a gram of ethane. This is because HFO-1234ze has a 
molecular weight (114) that is more than three times that of ethane 
(molecular weight 30), and thus requires less than a third the number 
of molecules of HFO-1234ze per gram than the number of molecules of 
ethane needed per gram.
    Thus, for both of the petitions submitted by Honeywell, the data 
supports the contention that the reactivity of the compound in the 
petition is equal to or lower than that of ethane on a mass MIR basis.
    We anticipate that one of these compounds, HFO-1234yf, will be used 
in automobiles as a replacement for the current refrigerant HFC-134a, 
which is the only use for which HFO-1234yf has been approved to date 
under the SNAP program. Given this one-for-one substitution situation, 
it is informative to compare the ozone forming potential of HFO-1234yf 
to that of HFC-134a, which has a gram MIR of only 0.0007 and thus 
contributes very little to ozone formation. The EPA has considered the 
results of a recent peer-reviewed study of the increase in ozone that 
may occur as result of the substitution of HFO-1234yf for HFC-134a.\1\ 
Based on air quality modeling, this study found that if HFO-1234yf was 
used in all automobiles but not in any other application, the 
incremental amount of ozone formed from its degradation in the 
atmosphere was only 0.01% of total ozone formed during the simulation 
due to emissions from all sources. This portion of ozone formation due 
to automobiles is slightly more than the current baseline, where the 
refrigerant used is HCF-134a.\2\ Thus, the additional information from 
this study shows that, under the assumptions used in the air quality 
modeling, the use of HFO-1234yf would produce more ozone than continued 
use of HFC-134a, but the increase is unlikely to have a significant 
impact on local air quality. One of the assumptions used in the 
modeling was that the substitution of one refrigerant for the other 
would not affect meteorological conditions that also influence ozone 
formation.
---------------------------------------------------------------------------

    \1\ D. Luecken, R. Waterland, S. Papasavva, K. Taddonio, W. 
Hutzell, J. Rugh, and S. Andersen. Ozone and TFA Impacts in North 
America from Degradation of 2,3,3,3-Tetrafluoropropene (HFO-1234yf), 
A Potential Greenhouse Gas Replacement. Environ. Sci. Technol. 44, 
pp. 343-349.
    \2\ The study also noted that if 2,3,3,3-tetrafluoropropene were 
used in additional applications that are currently not legal in the 
U.S, e.g., non-vehicle refrigerant applications, its contribution to 
ozone formation would be greater, but did not quantify this 
potential contribution.
---------------------------------------------------------------------------

    However, as stated in Section II.A, HFO-1234yf has a much lower GWP 
than HFC-134a. Global warming is predicted to exacerbate high ozone 
concentrations \3,4\, so directionally the lower GWP of HFO-1234yf will 
offset at least some of the ozone increase predicted by the modeling 
that assumed identical meteorological conditions. The EPA believes the 
very small increase in ozone concentrations that may result from 
encouraging the use of HFO-1234yf via an exemption from the

[[Page 64063]]

definition of VOC does not constitute a sufficient reason to depart 
from the Interim Guidance's reliance on MIR comparisons to ethane as 
the basis for approving VOC exemption requests.
---------------------------------------------------------------------------

    \3\ U.S. EPA. Assessment of the Impacts of Global Change on 
Regional U.S. Air Quality: A Synthesis of Climate Change Impacts on 
Ground-Level Ozone (An Interim Report of the U.S. EPA Global Change 
Research Program). U.S. Environmental Protection Agency, Washington, 
D.C., EPA/600/R-07/094F, 2009.
    \4\ Jacob, Daniel J. and Darrell A. Winner (2009). Effect of 
climate change on air quality, Atmospheric Environment, 43:51-63.
---------------------------------------------------------------------------

    In summary, for both HFO-1234yf and HFO-1234ze, the EPA believes 
that these chemicals qualify as negligibly reactive with respect to 
their contribution to tropospheric ozone formation.

B. Likelihood of Risk to Human Health or the Environment

    Additionally, we examined and present available information on the 
likelihood of risk to human health or the environment from increased 
use of the chemicals considered here. We believe that current 
regulation of these compounds under other EPA programs adequately 
protects human health and the environment.
    The only currently known or potential uses for the chemicals being 
considered here are as substitutes for stratospheric ozone-depleting 
substances (ODS), and any such use is regulated under the SNAP program. 
Under SNAP, the EPA reviews all new substitutes for ODS and allows 
their use in specific applications where the overall risks to human 
health and the environment associated with their use are comparable to 
or less than those of other compounds used in the same manner.
    After reviewing available information and public comments regarding 
its safety, health, and environmental risks and benefits under the SNAP 
program, the EPA issued a final approval on March 29, 2011 (76 FR 
174888) for HFO-1234yf as an acceptable ODS substitute for use in MVAC, 
subject to specific use conditions, in place of CFC-12 and HFC-134a.\5\ 
The use conditions in the SNAP approval have the effect of making it 
illegal to use HFO-1234yf in the air conditioning systems of heavy-duty 
trucks, refrigerated transport, or off-road vehicles such as 
agricultural or construction equipment. The use restrictions also have 
the effect of making use of the compound other than by manufacturers of 
automobiles and light-duty trucks or by commercial automotive service 
centers either illegal or highly unlikely.\6\
---------------------------------------------------------------------------

    \5\ HFC-134a, which is not an ozone depleting substance, has 
already largely replaced CFC-12 in motor vehicle air conditioners.
    \6\ While use by vehicle owners is not illegal, the SNAP 
conditions prevent the sale of HFO-1234yf in containers of the size 
that would be attractive to individual vehicle owners, and also 
include requirements for special connecting equipment for the large 
containers that are legal for sale. In addition, as described later 
in this notice, under a recent Significant New Use Rule anyone 
planning to distribute HFO-1234yf for use by a consumer would be 
required to notify the EPA before doing so.
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    In the SNAP review, the EPA found that the use of HFO-1234yf in new 
passenger vehicle and light-duty truck MVAC systems, subject to the use 
conditions, does not present a significantly greater risk to human 
health and the environment compared to the currently approved MVAC 
alternatives. In summary, the EPA's SNAP review reached the following 
conclusions in support of this finding.
     Substituting HFO-1234yf for HFC-134a is environmentally 
beneficial from a climate change perspective as the global warming 
potential of HFO-1234yf is much lower (100 year GWP of 4 for HFO-1234yf 
vs. 100 year GWP of 1430 for HFC-134a). The EPA received a petition on 
May 7, 2010, (with a follow up petition on November 16, 2010) from the 
Natural Resources Defense Council, the Institute for Governance & 
Sustainable Development, and the Environmental Investigation Agency (a 
non-governmental organization) asking the EPA to remove HFC-134a from 
the list of acceptable substitutes under the SNAP program for use in 
motor vehicle air conditioners. The petitioners cited this difference 
in GWP as a reason for the EPA to approve their request.
     The use conditions of the final SNAP approval for HFO-
1234yf provide protection against potential safety hazards related to 
the flammability of the compound, including potential exposure to 
hydrogen fluoride arising from thermal decomposition during a fire.
     Like HFC-134a, HFO-1234yf is not an ODS, so the 
substitution of the latter for the former will not affect stratospheric 
ozone concentrations.
     HFO-1234yf will not create significant impacts on ground 
level ozone or on local air quality.\7\
---------------------------------------------------------------------------

    \7\ In support of this conclusion, the final SNAP rule preamble 
cited two air quality modeling studies in addition to Luecken et al. 
These studies focused on air quality in Los Angeles, as a worst case 
scenario.
---------------------------------------------------------------------------

     The production of triflouroacetic acid from the 
atmospheric degradation of HFO-1234yf does not pose a significant risk 
of aquatic toxicity or ecosystem impacts.
     When used in accordance with the SNAP use restrictions, 
HFO-1234yf does not result in significantly greater risks to human 
health than the use of other available or potentially available 
substitutes.
    The EPA conclusion in the final SNAP action regarding human health 
risks of HFO-1234yf was based on an extensive risk assessment and 
review of public comments. The EPA also noted that under the TSCA, the 
EPA had recently performed a pre-manufacture review for HFO-1234yf and 
adopted the SNUR (75 FR 65987, Oct. 27, 2010). The SNUR for HFO-1234yf 
requires reporting of additional information to the EPA before sale may 
begin for uses beyond air conditioning in new automobiles or commercial 
servicing of new automobiles built using HFO-1234yf, i.e., the EPA must 
be given 90-days notice before HFO-1234yf products can be sold directly 
to consumers for the purpose of servicing, maintenance, and disposal. 
During these 90 days, the EPA can take further action to stop that 
marketing. This precautionary step was taken because of certain animal 
data indicating toxicity, and the possibility that home mechanics might 
accidentally expose themselves. Auto plant workers and repair shop 
professionals were expected to avoid exposure through work 
practices.\8\
---------------------------------------------------------------------------

    \8\ The EPA considered the results of developmental testing 
available at the time of the final SNUR action to be of some 
concern, but not a sufficient basis to find HFO-1234yf unacceptable 
under the SNUR determination. As a result, The EPA requested 
additional toxicity testing and issued the SNUR for HFO-1234yf. The 
EPA has received and is presently reviewing the results of the 
additional toxicity testing. The EPA continues to believe that HFO-
1234yf, when used in new automobile air conditioning systems in 
accordance with the use conditions under the SNAP rule, does not 
result in significantly greater risks to human health than the use 
of other available substitutes.
---------------------------------------------------------------------------

    Under the SNUR, the agency will: (a) Receive a Significant New Use 
Notice, or SNUN, of any person's intent to manufacture, import, or 
process HFO-1234yf for sale directly to consumers; (b) have an 
opportunity to review and evaluate data submitted with the SNUN; and 
(c) be able to regulate HFO-1234yf consumer products, if warranted. Any 
other potential applications beyond air conditioning in new automobiles 
or commercial servicing of new automobiles built using HFO-1234yf that 
may lead to significant exposures will also trigger the requirement for 
a SNUN, and would likely trigger further review under SNAP. The EPA 
believes these processes will provide adequate opportunity to address 
any health effects issues associated with possible increased use of 
HFO-1234yf.
    The EPA's SNAP program has also issued determinations of 
acceptability for HFO-1234ze as an acceptable substitute for certain 
ODS in a number of foam blowing end uses, as a refrigerant in non-
mechanical heat transfer, and as a propellant as stated in Section I. 
In this action, the EPA noted that HFO-1234ze is not ozone

[[Page 64064]]

depleting, the GWP for HFO-1234ze is significantly lower than the GWPs 
for the ozone-depleting substances it will replace, HFO-1234ze is not 
flammable, and the toxicity risks of HFO-1234ze are low. For these 
reasons, the EPA found that HFO-1234ze will not pose a greater overall 
risk to human health and the environment than the other substitutes 
acceptable in these end uses.

C. Conclusions

    In summary, for both HFO-1234yf and HFO-1234ze, the EPA believes 
that (a) these chemicals qualify as negligibly reactive with respect to 
their contribution to tropospheric ozone formation, and (b) any non-
tropospheric ozone related risks associated with potential increased 
use are adequately addressed by other existing programs and policies. 
We also believe that the much lower global warming potential of HFO-
1234yf compared to the compound HFC-134a for which it will substitute, 
as described in Section III.B, is an additional reason to approve the 
HFO-1234yf petition in particular, given that applying the Interim 
Guidance itself supports such approval. We invite the public to submit 
comments and additional information relevant to the issue of these 
compounds' overall risks and benefits to human health and the 
environment, and on whether such information should be considered in 
connection with the decision to grant an exemption from the regulatory 
definition of VOC.

IV. Proposed Action

    The EPA is responding to the petitions by proposing to revise its 
definition of VOC at 40 CFR 51.100(s) to add HFO-1234yf and HFO-1234ze 
to the list of compounds that are exempt from the regulatory definition 
of VOC because they are negligibly reactive on the basis that they are 
less reactive than ethane on a mass MIR basis. If an entity uses or 
produces any of these two compounds and is subject to the EPA 
regulations limiting the use of VOC in a product, limiting the VOC 
emissions from a facility, or otherwise controlling the use of VOC for 
purposes related to attaining the ozone NAAQS, then these two compounds 
will not be counted as a VOC in determining whether these regulatory 
obligations have been met. This action may also affect whether any of 
these two compounds are considered as VOCs for state regulatory 
purposes to reduce ozone formation, if a state relies on the EPA's 
definition of VOC. States are not obligated to exclude from control as 
a VOC those compounds that the EPA has found to be negligibly reactive. 
However, if this action is made final, states may not take credit for 
controlling these compounds in their ozone control strategies.

V. Statutory and Executive Order Reviews

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

    Under Executive Order (EO) 12866 (58 FR 51735, October 4, 1993), 
this action is treated as a significant regulatory action because some 
may view it as raising novel legal or policy issues arising out of 
legal mandates. Accordingly, the EPA submitted this action to the 
Office of Management and Budget (OMB) for review under EO 12866 and 
13563 (76 FR 3821, January 21, 2011) and any changes made in response 
to OMB recommendations have been documented in the docket for this 
action.

B. Paperwork Reduction Act

    This action does not impose an information collection burden under 
the provisions of the Paperwork Reduction Act, 44 U.S.C. 3501 et seq. 
Burden is defined at 5 CFR 1320.3(b). It does not contain any 
recordkeeping or reporting requirement.

C. Regulatory Flexibility Act

    The Regulatory Flexibility Act (RFA) generally requires an agency 
to prepare a regulatory flexibility analysis of any rule subject to 
notice and comment rulemaking requirements under the Administrative 
Procedure Act or any other statute unless the agency certifies that the 
proposed rule will not have a significant economic impact on a 
substantial number of small entities. Small entities include small 
businesses, small organizations, and small governmental jurisdictions. 
For purposes of assessing the impacts of this notice on small entities, 
small entity is defined as: (1) A small business that is a small 
industrial entity as defined in the U.S. Small Business Administration 
(SBA) size standards. (See 13 CFR 121.); (2) A governmental 
jurisdiction that is a government of a city, county, town, school 
district or special district with a population of less than 50,000; and 
(3) A small organization that is any not-for-profit enterprise which is 
independently owned and operated and is not dominant in its field.
    After considering the economic impacts of this proposed rule on 
small entities, I certify that this action will not have a significant 
economic impact on a substantial number of small entities. This 
proposed rule will not impose any requirements on small entities.
    We continue to be interested in the potential impacts of the 
proposed rule on small entities and welcome comments on issues related 
to such impacts.

D. Unfunded Mandates Reform Act

    This action contains no Federal mandates under the provisions of 
Title II of the Unfunded Mandates Reform Act of 1995 (UMRA), 2 U.S.C. 
1531-1538 for state, local, or Tribal governments or the private 
sector. The action imposes no enforceable duty on any state, local or 
Tribal governments, or the private sector. Therefore, this action is 
not subject to the requirements of sections 202 and 205 of the UMRA.
    This action is also not subject to the requirements of section 203 
of UMRA because it contains no regulatory requirements that might 
significantly or uniquely affect small governments.

E. Executive Order 13132--Federalism

    This action does not have federalism implications. It will not have 
substantial direct effects on the states, on the relationship between 
the national government and the states, or on the distribution of power 
and responsibilities among the various levels of government, as 
specified in Executive Order 13132. This action addresses the exemption 
of a set of chemical compounds from the VOC definition. Thus, Executive 
Order 13132 does not apply to this rule. In the spirit of Executive 
Order 13132, and consistent with the EPA policy to promote 
communications between the EPA and state and local governments, the EPA 
specifically solicits comment on this proposed rule from state and 
local officials.

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

    This action does not have Tribal implications, as specified in 
Executive Order 13175 (65 FR 67249, November 9, 2000). It will not have 
substantial direct effects on Tribal governments, on the relationship 
between the Federal government and Indian Tribes, or on the 
distribution of power and responsibilities between the Federal 
government and Indian Tribes, as specified in Executive Order 13175. 
Thus, Executive Order 13175 does not apply to this rule.
    Although Executive Order 13175 does not apply to this proposed 
rule, the EPA specifically solicits additional comment on this proposed 
rule from Tribal officials.

[[Page 64065]]

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

    This action is not subject to EO 13045 (62 FR 19885, April 23, 
1997) because it is not economically significant as defined in EO 
12866. While this proposed rule is not subject to the Executive Order, 
the EPA has reason to believe that ozone has a disproportionate effect 
on active children who play outdoors (62 FR 38856; 38859, July 18, 
1997). The EPA has not identified any specific studies on whether or to 
what extent these chemical compounds may affect children's health. The 
EPA has placed the available data regarding the health effects of HFO-
1234yf in Docket No. EPA-HQ-OAR-2003-0032 which is the docket for the 
SNUR for this compound.
    The public is invited to submit comments or identify peer-reviewed 
studies and data, of which the EPA may not be aware, that assess 
results of early life exposure to the chemical compounds herein.

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

    This action is not a ``significant energy action'' as defined in 
Executive Order 13211, ``Actions Concerning Regulations That 
Significantly Affect Energy Supply, Distribution, or Use'' (66 FR 
28355, May 22, 2001) because it is not likely to have a significant 
adverse effect on the supply, distribution, or use of energy. This 
action proposes to revise the EPA's definition of VOCs for purposes of 
preparing SIPs to attain the NAAQS for ozone under title I of the CAA.

I. National Technology Transfer and Advancement Act

    Section 12(d) of the National Technology Transfer and Advancement 
Act of 1995 (``NTTAA''), Public Law 104-113, section 12(d), (15 U.S.C. 
272 note) directs the EPA to use voluntary consensus standards in its 
regulatory activities unless to do so would be inconsistent with 
applicable law or otherwise impractical. Voluntary consensus standards 
are technical standards (e.g., materials specifications, test methods, 
sampling procedures, and business practices) that are developed or 
adopted by voluntary consensus standards bodies. The NTTAA directs the 
EPA to provide Congress, through OMB, explanations when the agency 
decides not to use available and applicable voluntary consensus 
standards. This rulemaking does not involve technical standards. 
Therefore, the EPA is not considering the use of any voluntary 
consensus standards.

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

    Executive Order (EO) 12898 (59 FR 7629, Feb. 16, 1994) establishes 
Federal executive policy on environmental justice. Its main provision 
directs Federal agencies, to the greatest extent practicable and 
permitted by law, to make environmental justice part of their mission 
by identifying and addressing, as appropriate, disproportionately high 
and adverse human health or environmental effects of their programs, 
policies, and activities on minority populations and low-income 
populations in the United States.
    The EPA has determined that this proposed rule will not have 
disproportionately high and adverse human health or environmental 
effects on minority or low-income populations because it will not 
affect the level of protection provided to human health or the 
environment.

List of Subjects in 40 CFR Part 51

    Environmental protection, Administrative practice and procedure, 
Air pollution control, Ozone, Reporting and recordkeeping requirements, 
Volatile organic compounds.

    Dated: October 11, 2011.
Lisa P. Jackson,
Administrator.
    For reasons set forth in the preamble, part 51 of chapter I of 
title 40 of the Code of Federal Regulations is proposed to be amended 
as follows:

PART 51--REQUIREMENTS FOR PREPARATION, ADOPTION, AND SUBMITTAL OF 
IMPLEMENTATION PLANS

    1. The authority citation for Part 51, Subpart F, continues to read 
as follows:

     Authority: 42 U.S.C. 7401, 7411, 7412, 7413, 7414, 7470-7479, 
7501-7508, 7601, and 7602.

Sec.  51.100  [Amended]

    2. Section 51.100 is amended at the end of paragraph (s)(1) 
introductory text by removing the words ``and perfluorocarbon compounds 
which fall into these classes:'' and adding in their place a semi-colon 
and the words ``trans-1,3,3,3-tetrafluoropropene; 2,3,3,3-
tetrafluoropropene and perfluorocarbon compounds which fall into these 
classes:''.

[FR Doc. 2011-26768 Filed 10-14-11; 8:45 am]
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