[Federal Register Volume 86, Number 191 (Wednesday, October 6, 2021)]
[Proposed Rules]
[Pages 55549-55560]
[FR Doc No: 2021-21031]

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 82

[EPA-HQ-OAR-2019-0698; FRL-7826.1-02-OAR]
RIN 2060-AV31

Protection of Stratospheric Ozone: Listing of Substitutes Under
the Significant New Alternatives Policy Program; Supplemental Proposal

AGENCY: Environmental Protection Agency (EPA).

ACTION: Supplemental notice of proposed rulemaking.

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SUMMARY: Pursuant to the U.S. Environmental Protection Agency's
Significant New Alternatives Policy program, the Agency is proposing,
as an

additional option, to list for a limited period of time certain
substances in the foamblowing sector, extruded polystyrene: Boardstock
and billet end-use, as acceptable, subject to narrowed use limits. This
proposal supplements the Agency's June 12, 2020, proposal with respect
to the proposed listings in the foam-blowing sector, taking into
consideration public comments and information received since issuance
of the initial proposal. In the June 12, 2020, proposal, EPA proposed
to list three foam blowing agent blends as acceptable. In this
supplemental proposal, EPA is proposing an additional approach to list
these blends as acceptable, subject to narrowed use limits, in the foam
blowing sector, extruded polystyrene: Boardstock and billet end-use,
from the effective date of a final rule based on this supplemental
proposal until January 1, 2023. The Agency is providing an opportunity
for public comment on this additional approach for the listings in the
foam blowing sector, as well as reopening the public comment period for
the proposed listings in the foam blowing sector in the June 12, 2020,
proposal. The Agency is not reopening for comment those other portions
of the June 12, 2020, proposal which are addressed in a separate final
rule issued May 6, 2021.

DATES: Comments on this supplemental proposal must be received on or
before November 22, 2021. Any party requesting a public hearing must
notify the contact listed below under FOR FURTHER INFORMATION CONTACT
by 5 p.m. Eastern Daylight Time on October 12, 2021. If a virtual
hearing is held, it will take place on or before October 21, 2021 and
further information will be provided on EPA's Stratospheric Ozone
website at www.epa.gov/snap.

ADDRESSES: You may send comments, identified by docket identification
(ID) number EPA-HQ-OAR-2019-0698, to the Federal eRulemaking Portal:
http://www.regulations.gov. Follow the online instructions for
submitting comments. Once submitted, comments cannot be edited or
withdrawn. EPA may publish any comment received to its public docket.
Do not submit electronically any information you consider to be
Confidential Business Information (CBI) or other information whose
disclosure is restricted by statute. Multimedia submissions (audio,
video, etc.) must be accompanied by a written comment. The written
comment is considered the official comment and should include
discussion of all points you wish to make. EPA will generally not
consider comments or comment contents located outside of the primary
submission (i.e., on the web, cloud, or other file sharing system). For
additional submission methods, EPA's full public comment policy,
information about CBI or multimedia submissions, and general guidance
on making effective comments, please visit https://www.epa.gov/dockets/commenting-epa-dockets. The EPA is temporarily suspending its Docket
Center and Reading Room for public visitors, with limited exceptions,
to reduce the risk of transmitting COVID-19. Our Docket Center staff
will continue to provide remote customer service via email, phone, and
webform. We encourage the public to submit comments via https://www.regulations.gov or email, as there may be a delay in processing
mail and faxes. Hand deliveries and couriers may be received by
scheduled appointment only. For further information on EPA Docket
Center services and the current status, please visit us online at
https://www.epa.gov/dockets.

FOR FURTHER INFORMATION CONTACT: Christina Thompson, Stratospheric
Protection Division, Office of Atmospheric Programs (Mail Code 6205T),
Environmental Protection Agency, 1200 Pennsylvania Ave. NW, Washington,
DC 20460; telephone number:<PHONE_NUMBER>; email address:
<EMAIL_ADDRESS>Notices and rulemakings under EPA's
Significant New Alternatives Policy program are available on EPA's
Stratospheric Ozone website at https://www.epa.gov/snap/snap-regulations.

SUPPLEMENTARY INFORMATION:

Table of Contents

I. General information
    A. Executive Summary and Background
    B. Does this action apply to me?
    C. What acronyms and abbreviations are used in the preamble?
II. What did EPA propose in the 2020 NPRM, including for extruded
polystyrene: boardstock and billet?
III. What public comments and publicly available information has EPA
included in the docket with respect to the proposed XPS listings
since issuing the 2020 NPRM?
    A. Public Comments
    B. Additional Information
IV. What is EPA proposing in this supplemental proposal?
    A. Listing of Three Blends of HFC-134a as Acceptable, Subject to
Narrowed Use Limits
    B. What are the three proposed HFC-134a blends and how do they
compare to other foam blowing agents in the same end-use?
    C. Status of Specific HFC Blends
V. Statutory and Executive Order Reviews
    A. Executive Order 12866: Regulatory Planning and Review 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
Population
VI. References

I. General Information

A. Executive Summary and Background

    Pursuant to the Significant New Alternatives Policy (SNAP) program,
EPA is proposing to list three foam blowing agent blends as acceptable,
subject to narrowed use limits, in the foam blowing sector, extruded
polystyrene: Boardstock and billet end-use. This proposal supplements
the Agency's June 12, 2020, Notice of Proposed Rulemaking (NPRM),
hereafter referred to as the ``2020 NPRM'' (85 FR 35874), with respect
to the proposal to list these blends as acceptable, taking into
consideration public comments and information received since issuance
of the initial proposal. In the 2020 NPRM, EPA proposed to list three
foam blowing agent blends as acceptable. In this supplemental proposal,
EPA is proposing an additional approach to list the following blends as
acceptable, subject to narrowed use limits, for use in extruded
polystyrene: Boardstock and billet (XPS):
     Blends of 40 to 52 percent hydrofluorocarbon (HFC)-134a
and the remainder hydrofluoroolefin (HFO)-1234ze(E);
     Blends of 40 to 52 percent HFC-134a with 40 to 60 percent
HFO-1234ze(E) and 10 to 20 percent each water and carbon dioxide
(CO2); and
     Blends with maximum of 51 percent HFC-134a, 17 to 41
percent HFC-152a, up to 20 percent CO2, and one to 13
percent water.
    If the approach discussed in this supplemental proposal is
finalized, all three blends would be acceptable subject to a narrowed
use limit for use in XPS from the effective date of a final rule based
on this supplemental proposal until January 1, 2023, where other
alternatives are not technically feasible for reasons of performance or

safety. EPA is taking comment on the proposed listings as well as the
specific narrowed use limits discussed in this supplemental proposal.
The Agency is also reopening the public comment period on the proposed
acceptable listings for the same three foam blowing blends in the 2020
NPRM, in light of information that has become publicly available and
included in the docket for this rulemaking after the comment period
closed for that proposal.
    In addition to listings for XPS, the 2020 NPRM included proposed
listings of refrigerants for use in certain refrigeration and air
conditioning end-uses, as well as a proposal to remove Powdered Aerosol
E from the list of fire suppression substitutes acceptable subject to
use conditions in total flooding applications. EPA is not reopening the
comment period for those other portions of the 2020 NPRM which were
addressed in a separate final rule (May 6, 2021; 86 FR 24444). Rather,
this supplemental proposal relates only to the XPS listings. EPA
intends to respond to comments on the 2020 NPRM's proposed listings for
XPS together with comments on this supplemental proposal in a future
final rule.
    This supplemental proposal is not EPA's response to the Mexichem
Fluor, Inc. v. EPA decision of the United States Court of Appeals for
the District of Columbia Circuit (``the D.C. Circuit'').\1\ In this
supplemental proposal, as in the 2020 NPRM, EPA refers to listings made
in a final rule issued on July 20, 2015. See 80 FR 42870 (``2015
Rule''). The 2015 Rule, among other things, changed the listings for
certain HFCs and blends from acceptable to unacceptable in various end-
uses in the aerosols, refrigeration and air conditioning, and foam
blowing sectors. After a challenge to the 2015 Rule, the D.C. Circuit
issued a partial vacatur of the 2015 Rule ``to the extent it requires
manufacturers to replace HFCs with a substitute substance'' \2\ and
remanded the rule to EPA for further proceedings.\3\ The D.C. Circuit
also upheld EPA's listing changes as being reasonable and not
``arbitrary and capricious.'' \4\ EPA intends to respond to the D.C.
Circuit's decision in a future action.
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    \1\ 866 F.3d 451 (D.C. Cir. 2017).
    \2\ 866 F.3d at 462.
    \3\ Later, the court issued a similar decision on portions of a
similar final rule issued December 1, 2016. 81 FR 86778 (``2016
Rule''). See Mexichem Fluor, Inc. v. EPA, Judgment, Case No. 17-1024
(D.C. Cir. Apr. 5, 2019), 760 F. App'x 6 (Mem).
    \4\ Mexichem Fluor, 866 F.3d at 462-63.
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    The SNAP program implements section 612 of the Clean Air Act (CAA).
Background on the SNAP program is provided in the 2020 NPRM.
    For additional information on the SNAP program, visit the SNAP
portion of EPA's Ozone Layer Protection website at www.epa.gov/snap.
Copies of the full lists of acceptable substitutes for ozone depleting
substances (ODS) in all industrial sectors are available at
www.epa.gov/snap/substitutes-sector. For more information on the
Agency's process for administering the SNAP program or criteria for
evaluation of substitutes, refer to the initial SNAP rulemaking
published on March 18, 1994 (59 FR 13044), codified at 40 CFR part 82,
subpart G. SNAP decisions and the appropriate Federal Register
citations are found at www.epa.gov/snap/snap-regulations. Substitutes
listed as unacceptable; acceptable, subject to narrowed use limits; or
acceptable, subject to use conditions, are also listed in the
appendices to 40 CFR part 82, subpart G.

B. Does this action apply to me?

    The following list identifies regulated entities that may be
affected by this proposed rule and their respective North American
Industrial Classification System (NAICS) codes:

     All Other Basic Organic Chemical Manufacturing (NAICS
325199)
     Polystyrene Foam Product Manufacturing (NAICS 326140)

C. What acronyms and abbreviations are used in the preamble?

    Below is a list of acronyms and abbreviations used in the preamble
of this document:

AIHA--American Industrial Hygiene Association
ASTM--American Society for Testing and Materials
CAA--Clean Air Act
CAS Reg. No.--Chemical Abstracts Service Registry Identification
Number
CBI--Confidential Business Information
CFR--Code of Federal Regulations
CO2--Carbon Dioxide
ECCC--Environment and Climate Change Canada
EPA--United States Environmental Protection Agency
EPS--Expanded Polystyrene
EU--European Union
FR--Federal Register
FTOC--Rigid and Flexible Foams Technical Options Committee
GWP--Global Warming Potential
HF--Hydrofluoric acid
HFC--Hydrofluorocarbon
HFO--Hydrofluoroolefin
ICF--ICF International, Inc.
IPCC--Intergovernmental Panel on Climate Change
NAICS--North American Industrial Classification System
NFPA--National Fire Protection Association
NIOSH--National Institute for Occupational Safety and Health
NPRM--Notice of Proposed Rulemaking
NRC--National Research Council
ODP--Ozone Depletion Potential
ODS--Ozone Depleting Substances
OMB--United States Office of Management and Budget
OSHA--United States Occupational Safety and Health Administration
PEL--Permissible Exposure Limit
PIR--Polyisocyanurate
ppm--Parts Per Million
PRA--Paperwork Reduction Act
RFA--Regulatory Flexibility Act
SDS--Safety Data Sheet
SNAP--Significant New Alternatives Policy
STEL--Short-term Exposure Limit
UMRA--Unfunded Mandates Reform Act
UL--Underwriters Laboratories, Inc.
USGCRP--U.S. Global Change Research Program
VOC--Volatile Organic Compounds
WEEL--Workplace Environmental Exposure Limit
WMO--World Meteorological Organization
XPS--Extruded Polystyrene: Boardstock and Billet

II. What did EPA propose in the 2020 NPRM, including for extruded
polystyrene: Boardstock and billet?

    In the 2015 Rule, EPA changed the status of HFC-134a for use in
XPS, from ``acceptable'' to ``acceptable subject to narrowed use limits
for military or space- and aeronautics-related applications'' and
``unacceptable for all other uses as of January 1, 2021,'' and as
``unacceptable for all uses as of January 1, 2022.'' In another final
rule issued December 1, 2016 (81 FR 86778), among other things, EPA
revised the change of status dates for XPS for space- and aeronautics-
related applications, such that they are ``acceptable subject to
narrowed use limits from January 1, 2021, through December 31, 2024,''
and ``unacceptable as of January 1, 2025.'' The December 1, 2016 final
rule also applied unacceptability determinations for foam blowing
agents to closed cell foam products and products containing closed cell
foam.
    In the 2020 NPRM, EPA proposed to list three blends containing HFC-
134a as acceptable blowing agents in XPS: Blends of 40 to 52 percent
HFC-134a by weight and the remainder HFO-1234ze(E); blends of 40 to 52
percent HFC-134a with 40 to 60 percent HFO-1234ze(E) and 10 to 20
percent each water and CO2 by weight; and blends with
maximum of 51 percent HFC-134a, 17 to 41 percent HFC-152a, up to 20
percent CO2 and 1 to 13 percent water. EPA also proposed to
revise the unacceptable listing for blends of certain HFCs in XPS for
consistency with the proposed acceptable listings for those blends of
HFC-134a. Redacted submissions and supporting

documentation for these blends are provided in the docket for this
proposed rule (EPA-HQ-OAR-2019-0698) at https://www.regulations.gov.\5\
\6\ \7\
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    \5\ Supporting Documentation for SNAP Rule 23 Listing of Blends
of 40 to 52 Percent HFC-134a by Weight and the Remainder HFO-
1234ze(E) in Extruded Polystyrene: Boardstock and Billet. Submission
Received July 20, 2017. Docket ID EPA-HQ-OAR-2019-0698-0023.
    \6\ Supporting Documentation for SNAP Rule 23 Listing of Blends
of 40 to 52 Percent HFC-134a with 40 to 60 Percent HFO-1234ze(E) and
10 to 20 Percent Each Water and CO2 by Weight in Extruded
Polystyrene: Boardstock and Billet. Submission Received September
24, 2018. Docket ID EPA-HQ-OAR-2019-0698-0024.
    \7\ Supporting Documentation for SNAP Rule 23 Listing of Blends
with Maximum of 51 Percent HFC-134a, 17 to 41 Percent HFC-152a, up
to 20 Percent CO2 and One to 13 Percent Water in Extruded
Polystyrene: Boardstock and Billet. Submission Received November 7,
2019. Docket ID EPA-HQ-OAR-2019-0698-0025.
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    In the 2020 NPRM, EPA proposed to list those three specific blends
of HFC-134a as acceptable in XPS, stating that ``[t]hese blends have
higher [global warming potentials] GWPs and are otherwise comparable or
lower in risk than other alternatives listed as acceptable; however,
EPA is taking this action because the Agency believes that other
acceptable alternatives are not generally available for most needs
under this end-use.'' 85 FR 35888.
    EPA also stated in the 2020 NPRM that, in order for substitutes to
be ``available'' in the XPS end-use, they must be capable of blowing
foam that meets the technical needs of XPS products including density
and ability to meet testing requirements of building codes and
standards, such as for thermal efficiency, compressive strength, and
flame and smoke generation (85 FR 35888). Further, EPA noted that the
company that initially submitted the three blends to the SNAP program
for review indicated their difficulty meeting requirements for
insulation value (``R-value'') with neat \8\ acceptable blowing agents
such as HFO-1234ze(E), HFC-152a, and CO2.\9\ The submitter
indicated that if in some cases it could meet R-value requirements with
those neat blowing agents, these alternatives were not able to meet
other requirements such as compressive strength, density and thickness,
or fire test results. The submitter also identified challenges with
meeting code requirements for XPS products manufactured with flammable
substitutes (e.g., HFC-152a, light saturated hydrocarbons C3-C6, and
methyl formate) and provided examples of failed test results \10\ (85
FR 35888).
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    \8\ Individual, unblended blowing agents.
    \9\ DuPont, 2019b. December 17, 2019 Letter from DuPont
Performance Building Solutions to EPA. Docket ID EPA-HQ-OAR-2019-
0698-0008.
    \10\ DuPont, 2019b. Op. cit.
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    Based on the evidence before the Agency at the time of the 2020
NPRM, EPA stated that it appeared that only one of the substitutes that
the Agency believed at the time of the 2015 Rule would be available for
use in XPS foam as of January 1, 2021, was in fact available, and that
it likely could only be used to meet the needs for some portion of the
XPS foams market.\11\ Based on concerns about ensuring that the needs
of the full XPS foams market in the United States could be met and not
limiting the choice of acceptable substitutes to only one option, EPA
proposed to list additional blowing agent options for XPS that have
been proven to work for this end-use.
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    \11\ In the 2020 NPRM, EPA further stated that the set of
products that may be able to be manufactured with that substitute,
HFC-152a, would account for a minority of the current market for XPS
(85 FR 35888, footnote 54). As discussed further below, the
statement that HFC-152a was being used alone may have been a
misunderstanding.
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    In the 2020 NPRM, EPA also proposed to revise the current
unacceptable listing for blends of certain HFCs in XPS in appendix U to
40 CFR part 82, subpart G. The listing for unacceptable substitutes in
XPS states that HFC-134a, HFC-245fa, HFC-365mfc, and blends thereof;
and Formacel TI, Formacel B, and Formacel Z-6 are ``unacceptable as of
January 1, 2021, except where allowed under a narrowed use limit.'' For
consistency with the proposed acceptable listings, EPA proposed to
revise this listing of unacceptable substitutes for XPS in appendix U
to read that the substitutes are ``Unacceptable as of January 1, 2021
except where allowed under a narrowed use limit or where blends are
specifically listed as acceptable.'' The 2020 NPRM further stated that
EPA was not opening up for comment other aspects of the existing
listing (85 FR 35889).
    The 2020 NPRM also included proposals that are not affected by this
supplemental proposal. Those were proposals for listing three
refrigerants as acceptable, subject to narrowed use limits, for use in
retail food refrigeration--medium-temperature stand-alone units for new
equipment and for listing six refrigerants as acceptable, subject to
use conditions, in certain types of new equipment for residential and
light commercial air conditioning and heat pumps, as well as a proposal
to remove Powdered Aerosol E from the list of fire suppression
substitutes that are ``acceptable subject to use conditions'' in total
flooding applications (85 FR 35874-75). The comment period for those
portions of the proposal ended on July 27, 2020. This supplemental
proposal does not reopen the comment period for those portions of the
2020 NPRM which were addressed in a separate final rule issued on May
6, 2021 (86 FR 24444).

III. What public comments and publicly available information has EPA
included in the docket with respect to the proposed XPS listings since
issuing the 2020 NPRM?

    During the public comment period for the 2020 NPRM, EPA received
comments with respect to the proposal to list three blends containing
HFC-134a as acceptable blowing agents in XPS. EPA also received and
found information related to the role of codes and standards for
residential insulation and the availability of alternative foam blowing
agents. These comments and additional information supplement the
information available to the Agency at the time of the 2020 NPRM and
are available in the public docket.

A. Public Comments

    In this section of the preamble, EPA is summarizing certain
relevant public comments that shared new information or suggested
different approaches to listing the three proposed blends. EPA also
received other public comments related to the proposed listings in the
2020 NPRM for three blends of HFC-134a for XPS that are not summarized
below. The Agency intends to address all comments on the 2020 NPRM and
on this supplemental proposal in any subsequent final rule.
    Most of the public comments on foam blowing agents for XPS in the
2020 NPRM opposed listing the proposed blends as acceptable, while two
manufacturers of XPS supported the proposed acceptable listings.
Opposing commenters stated that there are other alternatives
commercially available with lower GWP for use in XPS boardstock that
are currently being used in other countries, such as Japan, Saudi
Arabia, Canada, and member nations of the European Union (EU); and
those commenters provided links to further information. Those
commenters included one manufacturer of XPS, manufacturers of competing
types of foam insulation (e.g., polyisocyanurate [PIR] laminated
boardstock, expanded polystyrene [EPS]) and their trade organizations,
blowing agent producers, and environmental organizations. Two
environmental organizations provided information on recent research
into the use of CO2 as a blowing agent for XPS. Some of the
commenters also requested that EPA list additional blowing agents for
XPS that were under the SNAP program's review at the time of the 2020

NPRM. In contrast, the submitter of the three proposed blends commented
that because of differences in XPS manufacturing and code requirements
across jurisdictions, comparing XPS blowing agents between the U.S.,
Canada, and the EU is not appropriate. That commenter stated that they
had patented low-GWP blends for the Japanese market, but that those
blends could not meet the stricter fire codes in the North American
market. A different U.S. XPS manufacturer commented that they had been
using Formacel Z-6, a blend of HFC-152a, HFC-134a, and HFC-134, and
requested that EPA, if listing the three proposed blends as acceptable
in its final rule, clarify that the version of the Formacel Z-6 blend
used in the commenter's products is acceptable; at the time of the 2020
NPRM, EPA had incorrectly understood that this company was using neat
HFC-152a as their blowing agent.\12\
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    \12\ This misunderstanding was the basis for the Agency's
statements in the 2020 NPRM that ``one of the three manufacturers of
XPS in the United States has had some success using neat HFC-152a as
a blowing agent to manufacture some XPS products'' and ``only one of
the substitutes that the Agency believed at the time of the 2015
Rule would be available for use in XPS foam as of January 1, 2021 is
in fact available and likely could only be used to meet the needs
for some portion of the XPS foams market.'' 85 FR at 35888.
Subsequent to the 2020 NPRM, EPA has learned from public comments
that, in fact, no U.S. XPS manufacturers are using neat HFC-152a.
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    Some commenters mentioned that certain states have adopted
regulations that control HFCs.\13\ The submitter of the proposed blends
specifically mentioned timelines imposed by state regulations
prohibiting certain blowing agents in XPS as a reason why they needed
to use the proposed blends. An environmental group also noted in its
comments that to be ``fully compliant with the various state adoptions
of the Significant New Alternatives Policy (SNAP) Program in the United
States and Canadian Environmental Protection Act in Canada,'' as the
submitter claims, the submitter would need to use already-approved
substances.\14\ Another manufacturer of XPS commented that the majority
of the state laws that prohibit HFC-134a in XPS contemplate further
regulatory action ``to conform'' state law to any federal SNAP
requirement that approves a previously prohibited HFC blend for foam
blowing. This commenter expressed concern that EPA's decisions in the
rule could flow through to state law and that there could be
inappropriate environmental and potentially anticompetitive impacts if
EPA were to reach a conclusion (i.e., finalize the proposed listings
for the three blends in the 2020 NPRM) without knowledge of all U.S.
products available in the market.
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    \13\ To provide additional context, EPA notes that several
states have taken action to restrict the use of certain HFCs as foam
blowing agents for XPS that would prohibit use of HFC-134a or blends
thereof. To date, twelve of those states have issued final rules:
California, Colorado, Delaware, Maine, Maryland, Massachusetts, New
Jersey, New York, Rhode Island, Vermont, Virginia, and Washington.
Maine, Rhode Island, Vermont and Virginia have established a
compliance deadline of January 1, 2022; Delaware has a compliance
deadline of September 1, 2021; Maryland has a compliance deadline of
July 1, 2021; and the remaining six states have a compliance
deadline of January 1, 2021.
    \14\ EPA is aware of Canadian regulations (the Ozone-Depleting
Substances and Halocarbon Alternatives Regulations) which as of
January 1, 2021, prohibit the import and the manufacture of a
plastic foam or a rigid foam product in which a listed HFC
(including HFC-134a) is used as a foaming agent (i.e., blowing
agent) if the GWP of the foaming agent is greater than 150.
(Additional information is available about these regulations online
at https://pollution-waste.canada.ca/environmental-protection-registry/regulations/view?Id=129.) The regulations include
provisions to issue essential purpose permits that would allow for
the manufacture or import of a foam product if the product will be
used for an essential purpose and if a permit is specifically issued
under the regulations for that purpose. Environment and Climate
Change Canada (ECCC) issued essential purpose permits for the import
and/or manufacture of three companies' brands of extruded
polystyrene foam insulation boardstock with a foaming agent
containing HFCs and with a GWP below specified value. One of these
was an essential purpose permit expiring on December 31, 2022 for
XPS using a foam blowing agent containing HFCs and with a GWP of 750
or less manufactured by DuPont; this description corresponds with
the blends proposed in the 2020 NPRM and in this supplemental
proposal for XPS. ECCC also issued essential purpose permits
expiring on December 31, 2021 for XPS manufactured by Owens Corning
and by Kingspan Insulation. The information pertaining to essential
purpose permits issued by ECCC is available online at: https://www.canada.ca/en/environment-climate-change/services/canadian-environmental-protection-act-registry/permits/authorizations-ozone-depleting-substances.html.
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    Commenters disagree as to whether flammability of substitutes
currently listed as acceptable was of concern. Some commenters
commented that flammability risks of blowing agents already listed as
acceptable, and particularly of HFO-1234ze(E), were not significantly
different from flammability risks for HFC-134a. In contrast, the
original submitter of the proposed blends commented that during use of
HFO-1234ze(E) without HFC-134a, they had ``industrial hygiene'' events
where excessive hydrofluoric acid (HF) was generated due to
decomposition of the blowing agent under heat and more cases of
``unplanned combustion''; they reported that these problems were
resolved when using HFC-134a in the blend.
    Multiple commenters representing manufacturers of EPS or of PIR
foam insulation questioned statements in the preamble to the 2020 NPRM
concerning codes and standards and how they relate to having sufficient
options for the XPS end-use. For example, representatives of the EPS
industry commented that the specifications of American Society for
Testing and Materials (ASTM) Standard C578 are only required by
building codes in certain situations, such as use above-grade.
Commenters from the EPS industry stated that XPS products could still
be sold as a different type classification of insulation under the ASTM
C578 standard if they failed to meet the specifications for the type
classifications for which XPS typically is used (e.g., multiple types
requiring an R-value of at least 5 per inch). Manufacturers of XPS foam
responded to such comments in a presentation given to EPA,\15\ stating
that a change to a different type classification would impact their
ability to fill their customer's specific application needs and
reductions in R-value force an increase in product thicknesses to
comply with building energy codes. A commenter from the EPS industry
stated that there are a variety of flammability-related tests for
insulation foam, including both testing for flame and smoke generation
that is required by building codes (ASTM E84 or Underwriters
Laboratories [UL] 723) and others ``for which alternative solutions
exist in the code if the product fails these tests, such as FM [Factory
Mutual] 4880, NFPA [National Fire Protection Association] 286, UL 1715,
etc.''
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    \15\ DuPont, 2020a. August 23, 2020. DuPont Performance Building
Solutions. SNAP Rule 23 Discussion with EPA.
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    One commenter suggested that a sunset date be included for any
``Acceptable'' formulations that include high-GWP chemicals. This
commenter stated that that they recognize that change takes time and
suggested that the blends proposed in the 2020 NPRM provide a phased
approach to eventually eliminate high-GWP HFC foaming agents from XPS
products in the United States. The commenter also suggested that if the
EPA decides the three proposed blends should be added to the
``Acceptable'' list, the corresponding ``Unacceptable'' list should be
updated to include a deadline for these formulas and not be left open
ended. The submitter of the three proposed blends also mentioned timing
as a concern in their comments on the 2020 NPRM, stating non-flammable
blowing agent blends are necessary because of state regulatory
timelines for transition away from prohibited components of blowing
agents in XPS in some cases as early as January 1, 2021.

That commenter stated that products that meet qualification testing
with flammable blowing agents require longer development lead times.
The submitter of the three proposed blends subsequently sent EPA a late
comment, noting the other comment concerning a sunset date or deadline
for the proposed blends and stating that they would support the
inclusion of a two-year deadline for the blends in the final rule,
where the blends would no longer be ``acceptable'' after the deadline.
In this late comment, the submitter of the three proposed blends said
``[i]ncluding a deadline in the final rule could alleviate many of the
concerns raised by commenters, as a deadline would significantly limit
the scope of any alleged impacts of the rule.'' They also stated that
they are ``committed and actively working to find solutions with
further reduced [GWP],'' and that they ``view the SNAP Rule 23 blends
as a critical, but not permanent, step in [their] GWP phasedown plan.''
\16\ The EPA will address all comments received regarding these three
blends in the XPS end-use on the 2020 NPRM and on this supplemental
proposal in considering any final action on them.
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    \16\ DuPont, 2020b. November 20, 2020 Letter from J. Hansbro,
DuPont Performance Building Solutions, to C. Grundler and C.
Newberg, EPA. Available in docket EPA-HQ-OAR-2019-0698.
---------------------------------------------------------------------------

B. Additional Information

    The Agency has obtained additional information since issuance of
the 2020 NPRM. Some of this is information provided by commenters, such
as the names and websites of XPS manufacturers in Europe and Asia using
low-GWP blowing agents and a link to a report, ``Final Scientific
Report for DOE/EERE, A New Generation of Building Insulation by Foaming
Polymer Blend Materials with CO2'' (Industrial Science &
Technology Network, Inc. 2016).\17\ The information on the XPS
manufacturers in Europe and Asia indicates that a number of XPS
manufacturers globally are using foam-blowing agents that comply with
regulations restricting their GWP to 150 or less; however, there is not
corresponding information indicating that the same industry standards
or code requirements apply in these countries as in the United States.
The DOE/EERE report concerns an experimental technology for using
CO2 in XPS with improved thermal insulation values. The
report indicates that the technology is not yet commercially available.
EPA also has learned that the company Soprema, which manufactures XPS
in Europe using CO2, now operates a facility in Canada that
uses a blowing agent with a GWP less than 50 to manufacture XPS.\18\
---------------------------------------------------------------------------

    \17\ This report is in the docket for this rulemaking, EPA-HQ-
OAR-2019-0986, and is available online at https://www.osti.gov/servlets/purl/1244652.
    \18\ https://blog.soprema.ca/en/whats-new-with-sopra-xps.
---------------------------------------------------------------------------

    Other publicly available information included in the docket for
this rulemaking after the 2020 NPRM includes the 2018 report of the
Rigid and Flexible Foams Technical Options Committee (FTOC 2018). FTOC
2018 states that some reasons why CO2 could not be adopted
universally as a blowing agent include the following:
     Processing difficulties with CO2 and even
CO2/oxygenated hydrocarbon or CO2/hydrocarbon
blends;
     The higher gaseous thermal conductivity leading to poorer
thermal efficiency of the foam;
     Costs of conversion--including licensing constraints
resulting from patents; and
     Loss of processing flexibility ruling out some board
geometries completely. FTOC 2018 also states,

    CO2-based blends are now dominant in the European
extruded polystyrene (XPS) industry either alone or blended with
other blowing agents. . . . In North America where the lower lambda
[i.e., with higher thermal resistance and energy efficiency] product
is required, HFCs still dominate. By contrast, much of the European
XPS market is targeted at requirements, such as floor insulation,
where its moisture resistance is particularly valuable. In these
applications, board geometries are less critical.

In addition, since issuance of the 2020 NPRM, EPA has continued our
review of submissions for new substitutes for use in XPS. On December
11, 2020, the Agency listed blends of 10 to 99 percent by weight HFO-
1336mzz(Z) and the remainder HFC-152a as acceptable for use in XPS (85
FR 79863). Those blends have an ozone depletion potential (ODP) of
zero, range in GWP from about three to 110, contain chemicals that are
excluded from the definition of volatile organic compounds (VOC), are
flammable depending on the specific composition of the blend, and are
able to be used consistent with the workplace environmental exposure
limits (WEELs) for HFC-152a and for HFO-1336mzz(Z). For more detailed
information on the human health and environmental effects of these
blends, see ``Protection of Stratospheric Ozone: Determination 36 for
Significant New Alternatives Policy Program'' (85 FR 79863) and public
docket EPA-HQ-OAR-2003-0118 at www.regulations.gov. In addition, since
issuance of the 2020 NPRM, EPA's SNAP program has received and is
continuing its technical review of additional submissions of foam
blowing agents for use in XPS.

IV. What is EPA proposing in this supplemental proposal?

    Taking into consideration the information discussed in the 2020
NPRM, the public comments received on the 2020 NPRM and information
available to EPA since issuance of that initial proposal, EPA is
proposing to list the following three blends of HFC-134a as
``acceptable, subject to narrowed use limits,'' in XPS from the
effective date of a final rule based on this supplemental proposal
until January 1, 2023:
     Blends of 40 to 52 percent HFC-134a and the remainder HFO-
1234ze(E);
     Blends of 40 to 52 percent HFC-134a with 40 to 60 percent
HFO-1234ze(E) and 10 to 20 percent each water and CO2; and
     Blends with maximum of 51 percent HFC-134a, 17 to 41
percent HFC-152a, up to 20 percent CO2 and one to 13 percent
water.
    These are the same three blowing agent blends of HFC-134a that EPA
proposed to list as ``acceptable'' in the 2020 NPRM. Through this
supplemental proposal, EPA is offering an opportunity for comment on
modifications to the listings for these three blends proposed in the
2020 NPRM as well as the specific narrowed use limits. As noted above,
in light of information that has become publicly available and included
in the docket after the comment period closed for the 2020 NPRM, we are
also reopening the public comment period on the proposed listings in
the 2020 NPRM for these same three blends--i.e., listing the three
proposed blends as ``acceptable'' and changing the unacceptability
listing for HFC blends in XPS to allow for specific ``acceptable''
listings. You may find the proposed regulatory text at the end of this
document.

A. Listing of Three Blends of HFC-134a as Acceptable, Subject to
Narrowed Use Limits

    Under SNAP, listings of substitutes as ``acceptable, subject to
narrowed use limits,'' permit a narrowed range of use of a substitute
within an end-use or sector. As described in the 1994 SNAP Framework
Rule (Mar. 18, 1994) (59 FR 13044 at 13051), where EPA narrows uses, a
substitute will be acceptable for use only in certain applications
under SNAP, as where other alternatives are not technically feasible
due to performance or safety requirements. Thus, narrowed use limits
define in

which end-uses and applications an otherwise unacceptable substitute
may be used under SNAP.
    In this supplemental proposal, EPA is proposing to list the three
HFC-134a blends as ``acceptable, subject to narrowed use limits,''
because publicly available information that EPA has included in the
docket supports consideration of this additional option as an
alternative to the proposal to list them as ``acceptable'' without
restriction in the 2020 NPRM. This information indicates that a new
blowing agent is potentially available and others are likely to be
available in the future that would result in overall risk to human
health and the environment comparable to currently acceptable
substitutes and lower than the overall risks of the proposed blends.
Since issuance of the 2020 NPRM, EPA has listed another blowing agent
as acceptable for use in XPS: Blends of 10 to 99 percent by weight HFO-
1336mzz(Z) and the remainder HFC-152a. In addition, as commenters have
noted, other blowing agents such as HFO-1234ze(E) and CO2
are being used successfully for manufacturing XPS in other countries
where there are requirements to use blowing agents with a GWP less than
150. Accordingly, EPA is proposing to include a narrowed use limit in
the listing that would allow use under SNAP of the proposed blends in
XPS from the effective date of a final rule based on this supplemental
proposal until January 1, 2023, where other alternatives are not
technically feasible for reasons of performance or safety. At the same
time, EPA is proposing to list the three blends of HFC-134a as
acceptable, subject to narrowed use limits, because we understand that
U.S. XPS manufacturers are in the process of transitioning to other
lower GWP blowing agents, and we understand that additional technical
work is needed. For example, if an XPS manufacturer has not been using
highly or moderately flammable blowing agents in the past, it will
require additional time to test and adjust engineering controls to
address the higher degree of flammability and the greater amount of HF
that would be generated with the more flammable blowing agents. In
addition, even with non-flammable blowing agents such as
CO2, additional time would be required to test and, if
necessary, to adjust formulations or manufacturing processes, in order
to meet performance requirements. Based on a late comment from one XPS
manufacturer, we expect that it will take no more than two years from
the original change of status date of January 1, 2021, for that work to
be complete, such that these other blowing agents will be available and
can meet the needs met by current XPS products.
    EPA is proposing that the three proposed blends would be acceptable
from the effective date of the final rule associated with this
supplemental notice of proposed rulemaking--which we anticipate would
be 30 days after publication of a final rule in the Federal Register--
until January 1, 2023, to allow a limited time for fine-tuning of new
formulations currently in development. This timing would also be
consistent with a time period suggested in a late comment from the
submitter of the three blends. We note that we may issue a final rule
with a different time period e.g., 18 or 36 months after January 1,
2021, for example, if comments and information submitted during the
public comment period on this supplemental proposal indicate that a
different time period would be reasonable.
    The existing SNAP rules pertaining to narrowed use limits provide
that users intending to adopt a substitute ``acceptable with narrowed
use limits'' must ascertain that other alternatives are not technically
feasible and document the results of their evaluation that showed the
other alternatives to be not technically feasible and maintain that
documentation in their files. 40 CFR 82.180(b)(3). This documentation,
which does not need to be submitted to EPA unless requested to
demonstrate compliance, ``shall include descriptions of substitutes
examined and rejected, processes or products in which the substitute is
needed, reason for rejection of other alternatives, e.g., performance,
technical or safety standards, and the anticipated date other
substitutes will be available and projected time for switching to other
available substitutes.'' 40 CFR 82.180(b)(3).
    EPA is also reopening comment on the proposed ``acceptable''
listings for these three blends of HFC-134a from the 2020 NPRM, in
light of information that has become publicly available and included in
the public docket after the comment period closed for that proposal,
including the listing of another blowing agent as acceptable for use in
XPS (blends of 10 to 99 percent by weight HFO-1336mzz(Z) and the
remainder HFC-152a).\19\ Further, EPA requests comment on whether there
are likely to be adequate options available by January 1, 2023, that
would reduce overall risks to human health and the environment, and
whether those options would prove to be technically feasible and
sufficient in supply by that date to serve the full needs of the XPS
foam market. If, taking all the relevant and available information into
account, EPA were to conclude that there would not be adequate options,
or that the options would not prove to be technically feasible or
sufficient in supply, an acceptable, unrestricted listing without a
sunset date, as proposed in the 2020 NPRM, might be more appropriate
than a listing as ``acceptable subject to narrowed use limits'' or an
``acceptable'' listing with a sunset date.
---------------------------------------------------------------------------

    \19\ In this regard, EPA notes that section IV.B of this
supplemental proposal discusses the three proposed HFC-134a blends
and how they compare to other foam blowing agents in the same end-
use, including the most recently listed acceptable alternative.
---------------------------------------------------------------------------

    In the 2015 Rule, EPA changed the status of certain HFCs and HFC
blends from ``acceptable'' to ``unacceptable'' in XPS as of January 1,
2021, including HFC-134a, HFC-245fa, HFC-365mfc, and blends
thereof.\20\ Recognizing that multiple steps needed to be taken to
transition to other blowing agents, including research and testing, EPA
provided several years for those actions prior to the change of status
date of January 1, 2021. The Agency now anticipates that sufficient
alternatives will be available and technically feasible for XPS by
January 1, 2023. Thus, EPA is proposing to list additional blowing
agent options for XPS that have been proven to work for this end-use on
a limited basis by listing them as ``acceptable, subject to narrowed
use limits'' from the effective date of a final rule based on this
supplemental proposal until January 1, 2023.
---------------------------------------------------------------------------

    \20\ As noted above, the D.C. Circuit partially vacated and
remanded the 2015 Rule while also upholding EPA's listing changes as
being reasonable and not ``arbitrary and capricious.'' Mexichem
Fluor, 866 F.3d at 462-63. This supplemental proposal is not EPA's
response to the court's decision.
---------------------------------------------------------------------------

    EPA is taking comment on the proposed listings as well as the
specific narrowed use limits discussed above. In particular, EPA
requests comment on the appropriate time period for listing the blends
as ``acceptable, subject to narrowed use limits.'' We also request
comment on whether January 1, 2023, is a reasonable date or whether, as
noted above, the Agency should consider an earlier or later date in the
range of July 1, 2022 to January 1, 2024, and why. In addition, EPA is
considering whether there are other possible approaches to issuing a
time-limited acceptable listing for these three blends for use in the
XPS end-use, such as adding an ``acceptable'' listing with a sunset
date in the same range to the SNAP listings in 40 CFR part 82, subpart
G (e.g., listing as ``acceptable from the effective date of the final
rule to January 1, 2023''). This

alternative approach would have the effect of listing these three
blends as acceptable for a similar, limited time as for the proposal to
list the blends as ``acceptable, subject to narrowed use limits,'' but
the time limitation would not be expressed as a narrowed use limit.
Under this alternative approach, the user would not need to ascertain
further that other alternatives are not technically feasible, document
the results of their evaluation that showed the other alternatives to
be not technically feasible, or maintain that documentation in their
files, unlike with narrowed use limits.\21\ EPA solicits comments on
this alternative approach.
---------------------------------------------------------------------------

    \21\ I.e., under the alternative approach, it would not be
necessary to meet the requirements of 40 CFR 82.180(b)(3).
---------------------------------------------------------------------------

B. What are the three proposed HFC-134a blends and how do they compare
to other foam blowing agents in the same end-use?

    EPA notes that the information in this section is similar to that
provided in the 2020 NPRM (85 FR at 35887), but is updated to reflect
the most recent listing of acceptable substitutes for XPS (December 11,
2020; 85 FR 79863). In addition, EPA has updated GWP values to use the
100-year GWP from the Assessment of Ozone Depletion: 2018 (WMO, 2018)
for certain compounds that did not have a GWP value published in the
International Panel on Climate Change's Fourth Assessment Report (e.g.,
HFOs, methyl formate).
    EPA is proposing to list as ``acceptable subject to narrowed use
limits'' (1) blends of 40 to 52 percent HFC-134a by weight and the
remainder HFO-1234ze(E) for use in XPS (hereafter referred to as ``HFC-
134a/HFO-1234ze(E) blends''); (2) blends of 40 to 52 percent HFC-134a
with 40 to 60 percent HFO-1234ze(E) and 10 to 20 percent each water and
CO2 by weight for use in XPS (hereafter referred to as
``CO2/water/HFC-134a/HFO-1234ze(E) blends''); and (3) blends
with maximum of 51 percent HFC-134a, 17 to 41 percent HFC-152a, up to
20 percent CO2 and 1 to 13 percent water (hereafter referred
to as ``HFC-134a/HFC-152a/CO2/water blends''). The
components of the blends are co-blown and component percentages are by
weight.
    HFC-134a is also known as 1,1,1,2-tetrafluoroethane (CAS Reg. No.
811-97-2). HFC-152a, also known as 1,1, difluoroethane, has CAS Reg.
No. 75-37-6. HFO-1234ze is also known as HFC-1234ze, HFO-1234ze(E) or
trans-1,3,3,3-tetrafluoroprop-1-ene (CAS Reg. No. 29118-24-9).
CO2 has CAS Reg. No. 124-38-9, and water has CAS Reg. No.
7732-18-5.
    Redacted submissions and supporting documentation for these blends
are provided in the docket related to this supplemental proposal (EPA-
HQ-OAR-2019-0698) at https://www.regulations.gov. EPA performed
assessments to examine the health and environmental risks of these
substitutes. These assessments are available in the docket related to
this supplemental proposal.22 23 24
---------------------------------------------------------------------------

    \22\ ICF, 2020a. Risk Screen on Substitutes in Extruded
Polystyrene Boardstock and Billet Foam; Substitute: Blends of 40 to
52 Percent HFC-134a by Weight and the Remainder HFO-1234ze(E) (HFC-
HFO Co-blowing Agents).
    \23\ ICF, 2020b. Risk Screen on Substitutes in Extruded
Polystyrene Boardstock and Billet Foam; Substitute: Blends of 40 to
52 Percent HFC-134a with 40 to 60 Percent HFO-1234ze(E) and 10 to 20
Percent Each Water and CO2 by Weight (Co-blowing Blends).
    \24\ ICF, 2020c. Risk Screen on Substitutes in Extruded
Polystyrene Boardstock and Billet Foam; Substitute: Blends with
Maximum of 51 Percent HFC-134a, 17 to 41 Percent HFC-152a, up to 20
Percent CO2 and One to 13 Percent Water (Blends for Foam
Blowing).
---------------------------------------------------------------------------

    Environmental information: The substitutes have ODPs of zero. Their
components, HFC-134a, HFC-152a, HFO-1234ze(E), CO2, and
water have GWPs of 1,430,\25\ 124,\26\ one,\27\ one,\28\ and less than
one,\29\ respectively. If these values are weighted by mass percentage,
then the blends range in GWP from about 580 to 750.\30\ HFC-134a, HFC-
152a, HFO-1234ze(E), CO2, and water--components of the
blends--are excluded from EPA's regulatory definition of VOC under CAA
regulations that address the development of state implementation plans
to attain and maintain the National Ambient Air Quality Standards. See
40 CFR 51.100(s).
---------------------------------------------------------------------------

    \25\ IPCC, 2007. Climate Change 2007: The Physical Science
Basis. Contribution of Working Group I to the Fourth Assessment
Report of the Intergovernmental Panel on Climate Change. Solomon,
S., Qin, D., Manning, M., Chen, Z., Marquis, M., Averyt, K.B.,
Tignor, M., and Miller, H.L. (eds.). Cambridge University Press.
Cambridge, United Kingdom and New York, NY, USA. Available online
at: www.ipcc.ch/publications_and_data/ar4/wg1/en/contents.html.
    \26\ IPCC, 2007.
    \27\ WMO (World Meteorological Organization), Scientific
Assessment of Ozone Depletion: 2018, Global Ozone Research and
Monitoring Project--Report No. 58, 588 pp., Geneva, Switzerland,
2018. Available at: https://ozone.unep.org/sites/default/files/2019-05/SAP-2018-Assessment-report.pdf. In this action, the 100-year GWP
values are used.
    \28\ IPCC, 2007.
    \29\ Sherwood et al 2018. This paper estimated that water vapor
emitted near Earth's surface due to anthropogenic sources (e.g.
irrigation) would have a GWP of -10-3 to 5 x
10-4. ``The global warming potential of near-surface
emitted water vapour,'' Steven C Sherwood, Vishal Dixit and
Chrys[eacute]is Salomez. Environ. Res. Lett. 13 (2018) 104006.
    \30\ A GWP of 580 corresponds to formulations containing
approximately 40 percent HFC-134a and the remainder either HFO-
1234ze(E); HFO-1234ze(E), CO2, and water; or HFC-152a,
CO2, and water. A GWP of 750 corresponds to formulations
containing 52 percent HFC-134a and the remainder either HFO-
1234ze(E); HFO-1234ze(E), CO2, and water; or
alternatively containing 51 percent HFC-134a and the remainder HFC-
152a, CO2, and water.
---------------------------------------------------------------------------

    Flammability information: The component HFC-152a is moderately
flammable. The other components of the blends are non-flammable at
standard temperature and pressure using the standard test method ASTM
E681. However, at higher temperatures, such as the temperatures typical
for extruding XPS, HFC-134a and HFO-1234ze(E) may be flammable,
particularly at higher humidity levels.\31\ The XPS manufacturer
submitting the blends has found that blends containing 50 percent or
more HFC-134a have acceptable flammable process stability under
conditions of use (i.e., XPS extrusion).\32\
---------------------------------------------------------------------------

    \31\ Bellair and Hood, 2019. Comprehensive evaluation of the
flammability and ignitability of HFO-1234ze, R.J. Bellair and L.
Hood, Process Safety and Environmental Protection 132 (2019) 273-
284. Available online at doi.org/10.1016/j.psep.2019.09.033.
    \32\ DuPont, 2019a. August 23, 2019. Letter from DuPont
Performance Building Solutions to EPA. Docket ID EPA-HQ-OAR-2019-
0698-0007.
---------------------------------------------------------------------------

    Toxicity and exposure data: Potential health effects of these
substitutes at lower concentrations include headache, nausea,
drowsiness, and dizziness. The substitutes may also irritate the skin
or eyes or cause frostbite. At sufficiently high concentrations, they
may cause central nervous system depression and affect respiration. The
substitutes could cause asphyxiation, if air is displaced by vapors in
a confined space. These health effects are common to many foam blowing
agents.
    The American Industrial Hygiene Association (AIHA) has established
WEELs of 1,000 ppm as an eight-hour time-weighted average for HFC-134a
and HFC-152a and 800 ppm for HFO-1234ze(E). CO2 has an eight
hour/day, 40 hour/week permissible exposure limit (PEL) of 5000 ppm in
the workplace required by the Occupational Safety and Health
Administration (OSHA), and a 15-minute recommended short-term exposure
limit (STEL) of 30,000 ppm established by the National Institute for
Occupational Safety and Health (NIOSH). EPA anticipates that users will
be able to meet the AIHA WEELs, OSHA PEL, and NIOSH STEL and address
potential health risks by following requirements and recommendations in
the manufacturer's safety data sheets (SDSs) and other safety
precautions common to the foam blowing industry.
    Comparison to other substitutes in this end-use: HFC-134a/HFO-
1234ze(E)

blends, CO2/water/HFC-134a/HFO-1234ze(E) blends, and HFC-
134a/HFC-152a/CO2/water blends have ODPs of zero, comparable
to all other acceptable substitutes in this end-use, such as blends of
10 to 99 percent by weight HFO-1336mzz(Z) and the remainder HFC-152a
\33\ (hereafter called ``HFO-1336mzz(Z)/HFC-152a blends''), HFC-152a,
HFO-1234ze(E), methyl formate, and CO2.
---------------------------------------------------------------------------

    \33\ These blends range in composition from 10 percent HFO-
1336mzz(Z) and 90 percent HFC-152a to 99 percent HFO-1336mzz(Z) and
1 percent HFC-152a.
---------------------------------------------------------------------------

    The GWPs of 580 to 750 for the HFC-134a/HFO-1234ze(E) blends, the
CO2/water/HFC-134a/HFO-1234ze(E) blends, and HFC-134a/HFC-
152a/CO2/water blends are higher than those for acceptable
alternatives such as HFC-152a, HFO-1234ze(E), HFO-1336mzz(Z)/HFC-152a
blends, light saturated hydrocarbons C3-C6 \34\ and methyl formate,
with respective GWPs of 124, less than one, \35\ three to 110,\36\ less
than one,\37\ and 11.\38\
---------------------------------------------------------------------------

    \34\ That is, alkanes with three to six carbons such as butane,
n-pentane, isopentane, and cyclopentane.
    \35\ WMO, 2018.
    \36\ HFO-1336mzz(Z) and HFC-152a, have GWPs of about two (WMO,
2018) and 124 (IPCC, 2007), respectively. If these values are
weighted by mass percentage, then the blends range in GWP from about
three to about 110.
    \37\ WMO, 2018.
    \38\ WMO, 2018.
---------------------------------------------------------------------------

    Information regarding the flammability and toxicity of other
acceptable alternatives is provided in the listing decisions previously
made (see https://www.epa.gov/snap/substitutes-polystyrene-extruded-boardstock-and-billet). Flammability and toxicity risks of the HFC-
134a/HFO-1234ze(E), the CO2/water/HFC-134a/HFO-1234ze(E)
blends, and HFC-134a/HFC-152a/CO2/water blends are
comparable to or lower than flammability and toxicity risks of other
available substitutes in the same end-use. Toxicity risks can be
minimized by use consistent with the AIHA WEELs, OSHA PEL, NIOSH STEL,
recommendations in the manufacturer's SDSs, and other safety
precautions common in the foam-blowing industry.

C. Status of Specific HFC Blends

    The existing SNAP listings in appendix U to 40 CFR subpart G
include an unacceptable listing for XPS for ``HFC-134a, HFC-245fa, HFC-
365mfc, and blends thereof; Formacel TI, Formacel B, and Formacel Z-6''
under which those alternatives are ``unacceptable as of January 1,
2021, except where allowed under a narrowed use limit.'' In the 2020
NPRM, EPA proposed to revise this listing of unacceptable substitutes
for XPS to add an exception to the unacceptability of blends of HFC-
134a, HFC-245fa, or HFC-365mfc for cases ``where blends are
specifically listed as acceptable.'' 85 FR 35889. That change was
proposed to allow for consistency between the proposed acceptable
listings for these blends for XPS in the 2020 NPRM and the existing
unacceptable listing for HFC-134a, HFC-245fa, HFC-365mfc, and blends
thereof; and Formacel TI, Formacel B, and Formacel Z-6. EPA notes that
if we finalize the proposed change of listing the three blends of HFC-
134a as ``acceptable, subject to narrowed use limits,'' no change would
be needed to appendix U for consistency, as the existing listing
already includes the text ``except where allowed under a narrowed use
limit.''

V. Statutory and Executive Order Reviews

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

    This action is a significant regulatory action that was submitted
to the Office of Management and Budget (OMB) for review. Any changes
made in response to OMB recommendations have been documented in the
docket.

B. Paperwork Reduction Act (PRA)

    This action does not impose any new information collection burden
under the PRA. OMB has previously approved the information collection
activities contained in the existing regulations and has assigned OMB
control number 2060-0226. The approved Information Collection Request
includes five types of respondent reporting and recordkeeping
activities pursuant to SNAP regulations: Submission of a SNAP petition,
filing a Toxic Substances Control Act/SNAP Addendum, notification for
test marketing activity, recordkeeping for substitutes acceptable
subject to use restrictions, and recordkeeping for small volume uses.
This rule contains no new requirements for reporting or recordkeeping.

C. Regulatory Flexibility Act (RFA)

    I certify that this action will not have a significant economic
impact on a substantial number of small entities under the RFA. This
action will not impose any requirements on small entities. The
companies that may consider using the proposed blends, manufacturers of
XPS products, are not small businesses.

D. Unfunded Mandates Reform Act (UMRA)

    This action does not contain any unfunded mandate as described in
UMRA, 2 U.S.C. 1531-1538, and does not significantly or uniquely affect
small governments. The action imposes no enforceable duty on any state,
local, or tribal governments, or the private sector.

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.

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

    This action does not have tribal implications as specified in
Executive Order 13175. 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 action. EPA periodically updates tribal officials on air
regulations through the monthly meetings of the National Tribal Air
Association and will share information on this rulemaking through this
and other fora.

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

    This action is not subject to Executive Order 13045 because it is
not economically significant as defined in Executive Order 12866, and
because EPA does not believe the environmental health or safety risks
addressed by this action present a disproportionate risk to children.
The EPA has not conducted a separate analysis of risks to infants and
children associated with this rule. Any risks to children are not
different than the risks to the general population. This action's
health and risk assessments are contained in the comparisons of
toxicity for the various substitutes, as well as in the risk screens
for the substitutes that are proposed to be listed. The risk screens
are in the docket for this rulemaking.

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

    This action is not a ``significant energy action'' because it is
not likely to

have a significant adverse effect on the supply, distribution, or use
of energy. The blowing agents proposed in this action would enable the
continued manufacture of insulation foam that maintain current levels
of thermal efficiency.

I. National Technology Transfer and Advancement Act

    This rulemaking does not involve technical standards.

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

    A regulatory action may involve potential environmental justice
concerns if it could (1) create new disproportionate impacts on
minority populations, low-income populations, and/or indigenous
peoples; (2) exacerbate existing disproportionate impacts on minority
populations, low-income populations, and/or indigenous peoples; or (3)
present opportunities to address existing disproportionate impacts on
minority populations, low-income populations, and/or indigenous peoples
through the action under development.
    In EPA's 2009 and 2016 Endangerment Findings, the Administrator
considered climate change risks to minority populations and low-income
populations, finding that certain parts of the population may be
especially vulnerable based on their characteristics or circumstances,
including the poor, the elderly, the very young, those already in poor
health, the disabled, those living alone, and/or indigenous populations
dependent on one or limited resources due to factors including but not
limited to geography, access, and mobility. More recent assessment
reports by the U.S. Global Change Research Program (USGCRP), the
Intergovernmental Panel on Climate Change (IPCC), and the National
Research Council of the National Academies (NRC) demonstrate that the
potential impacts of climate change raise environmental justice issues.
These reports concluded that poorer communities can be especially
vulnerable to climate change impacts because they tend to have more
limited adaptive capacities and are more dependent on climate-sensitive
resources such as local water and food supplies. In corollary, some
communities of color--specifically, populations defined jointly by both
ethnic/racial characteristics and geographic location--may be uniquely
vulnerable to climate change health impacts in the United States.
Native American tribal communities possess unique vulnerabilities to
climate change, particularly those impacted by degradation of natural
and cultural resources within established reservation boundaries and
threats to traditional subsistence lifestyles. Tribal communities whose
health, economic well-being, and cultural traditions that depend upon
the natural environment will likely be affected by the degradation of
ecosystem goods and services associated with climate change.
    The EPA believes that this action does not have disproportionately
high and adverse human health or environmental effects on minority
populations, low-income populations, and/or indigenous peoples, as
specified in Executive Order 12898 (February 16, 1994; 59 FR 7629). In
light of the controls on production and consumption of HFCs under the
American Innovation and Manufacturing Act (December 27, 2020; Pub.
L.116-260), if the proposed listings were finalized, they would not be
expected to change the overall amount of HFCs manufactured or imported
in the United States or to adversely impact the climate. Additionally,
this limited action does not present a meaningful opportunity to
address existing disproportionate impacts.
    EPA's analysis indicates that other environmental impacts and human
health impacts of the proposed substitutes are comparable to or less
than those of other substitutes that are listed as acceptable for the
same end-use. For EPA's analysis of the human health and environmental
impacts of these substitutes, see the risk screens in the public docket
for this rulemaking (ICF, 2020a; ICF, 2020b; ICF, 2020c). The limited
period of time for the proposed listings in this supplemental proposal
would further reduce any impacts compared to the proposed listings for
XPS in the 2020 NPRM. Based on these considerations, EPA expects that,
if this supplemental proposal becomes final as proposed, the effects on
minority populations, low-income populations, and/or indigenous peoples
would not be disproportionately high and adverse.

VI. References

    Unless specified otherwise, all documents are available
electronically through the Federal Docket Management System, Docket
number EPA-HQ-OAR-2019-0698.

Bellair and Hood, 2019. Bellair, R.J. and Hood, L. Comprehensive
evaluation of the flammability and ignitability of HFO-1234ze.
Process Safety and Environmental Protection 132, 273-284. Available
online at doi.org/10.1016/j.psep.2019.09.033.
DuPont, 2019a. August 23, 2019. Letter from DuPont Performance
Building Solutions to EPA. Docket ID EPA-HQ-OAR-2019-0698-0007.
DuPont, 2019b. December 17, 2019 Letter from DuPont Performance
Building Solutions to EPA. Docket ID EPA-HQ-OAR-2019-0698-0008.
DuPont, 2020a. August 23, 2020. DuPont Performance Building
Solutions. SNAP Rule 23 Discussion with EPA.
DuPont, 2020b. November 20, 2020 Letter from J. Hansbro, DuPont
Performance Building Solutions, to C. Grundler and C. Newberg, EPA.
FTOC, 2018. 2018 Report of the Rigid and Flexible Foams Technical
Options Committee. 2018 Assessment Report. Available online at
https://ozone.unep.org/science/assessment/teap.
ICF, 2020a. Risk Screen on Substitutes in Extruded Polystyrene
Boardstock and Billet Foam; Substitute: Blends of 40 to 52 Percent
HFC-134a by Weight and the Remainder HFO-1234ze(E) (HFC-HFO Co-
blowing Agents).
ICF, 2020b. Risk Screen on Substitutes in Extruded Polystyrene
Boardstock and Billet Foam; Substitute: Blends of 40 to 52 Percent
HFC-134a with 40 to 60 Percent HFO-1234ze(E) and 10 to 20 Percent
Each Water and CO2 by Weight (Co-blowing Blends).
ICF, 2020c. Risk Screen on Substitutes in Extruded Polystyrene
Boardstock and Billet Foam; Substitute: Blends with Maximum of 51
Percent HFC-134a, 17 to 41 Percent HFC-152a, up to 20 Percent
CO2 and One to 13 Percent Water (Blends for Foam
Blowing).
Industrial Science & Technology Network, Inc. 2016. Final Scientific
Report for DOE/EERE, A New Generation of Building Insulation by
Foaming Polymer Blend Materials with CO2. Industrial
Science & Technology Network, Inc. Available online at: https://www.osti.gov/servlets/purl/1244652.
IPCC, 2007. Climate Change 2007: The Physical Science Basis.
Contribution of Working Group I to the Fourth Assessment Report of
the Intergovernmental Panel on Climate Change. Solomon, S., Qin, D.,
Manning, M., Chen, Z., Marquis, M., Averyt, K.B., Tignor, M., and
Miller, H.L. (eds.). Cambridge University Press. Cambridge, United
Kingdom and New York, NY, USA. Available online at: www.ipcc.ch/
publications_and_data/ar4/wg1/en/contents.html.
Sherwood et al. 2018. Sherwood, S.C., Vishal, D., and Salomez, C.
(2018) The global warming potential of near-surface emitted water
vapour. Environ. Res. Lett.,13 104006. Available online at https://iopscience.iop.org/article/10.1088/1748-9326/aae018/pdf.
WMO (World Meteorological Organization), Scientific Assessment of
Ozone Depletion: 2018, Global Ozone Research and Monitoring
Project--Report No. 58, 588 pp., Geneva, Switzerland, 2018.

Available at: https://ozone.unep.org/sites/default/files/2019-05/SAP-2018-Assessment-report.pdf.

List of Subjects in 40 CFR Part 82

    Environmental protection, Administrative practice and procedure,
Air pollution control, Reporting and recordkeeping requirements,
Stratospheric ozone layer.

Michael S. Regan,
Administrator.
    For the reasons set forth in the preamble, EPA proposes to amend 40
CFR part 82 as follows:

PART 82--PROTECTION OF STRATOSPHERIC OZONE

0
1. The authority citation for part 82 continues to read as follows:

    Authority: 42 U.S.C. 7414, 7601, 7671-7671q.

Subpart G--Significant New Alternatives Policy Program

0
2. In appendix W to subpart G of part 82:
0
a. Revise the heading for appendix W to subpart G of part 82.
0
b. Add a table titled ``Foam Blowing Agents--Substitutes Acceptable
Subject to Narrowed Use Limits'' after the table titled
``Refrigerants--Substitutes Acceptable Subject to Use Conditions''.
    The addition and revision read as follows:

Appendix W to Subpart G of Part 82--Substitutes Listed in the May 6,
2021 Final Rule and the [Date of publication of final rule in the
Federal Register] Final Rule--Effective June 7, 2021 and [Date 30 days
after date of publication of the final rule in the Federal Register]

* * * * *

                   Foam Blowing Agents--Substitutes Acceptable Subject to Narrowed Use Limits
----------------------------------------------------------------------------------------------------------------
            End-use                Substitute         Decision       Narrowed use limits    Further information
----------------------------------------------------------------------------------------------------------------
Extruded Polystyrene:           Blends of 40 to   Acceptable        Acceptable from
 Boardstock and Billet.          52 percent HFC-   Subject to        [insert date 30 days
                                 134a by weight    Narrowed Use      after date of
                                 and the           Limits.           publication of final
                                 remainder HFO-                      rule] until January
                                 1234ze(E).                          1, 2023: only for
                                                                     use where reasonable
                                                                     efforts have been
                                                                     made to ascertain
                                                                     that other
                                                                     alternatives are not
                                                                     yet technically
                                                                     feasible for reasons
                                                                     of performance or
                                                                     safety.
                                                                    Users are required to
                                                                     document and retain
                                                                     the results of their
                                                                     technical
                                                                     investigation of
                                                                     alternatives for the
                                                                     purpose of
                                                                     demonstrating
                                                                     compliance.
                                                                     Information shall
                                                                     include descriptions
                                                                     of:
                                                                     Process or
                                                                     product in which the
                                                                     substitute is
                                                                     needed;
                                                                     Substitutes
                                                                     examined and
                                                                     rejected;
                                                                     Reason for
                                                                     rejection of other
                                                                     alternatives, e.g.,
                                                                     performance,
                                                                     technical or safety
                                                                     standards; and/or
                                                                     Anticipated
                                                                     date other
                                                                     substitutes will be
                                                                     available and
                                                                     projected time for
                                                                     switching.
Extruded Polystyrene:           Blends of 40 to   Acceptable        Acceptable from
 Boardstock and Billet.          52 percent HFC-   Subject to        [insert date 30 days
                                 134a with 40 to   Narrowed Use      after date of
                                 60 percent HFO-   Limits.           publication of final
                                 1234ze(E) and                       rule] until January
                                 10 to 20                            1, 2023: Only for
                                 percent each                        use where reasonable
                                 water and CO2                       efforts have been
                                 by weight.                          made to ascertain
                                                                     that other
                                                                     alternatives are not
                                                                     yet technically
                                                                     feasible for reasons
                                                                     of performance or
                                                                     safety.
                                                                    Users are required to
                                                                     document and retain
                                                                     the results of their
                                                                     technical
                                                                     investigation of
                                                                     alternatives for the
                                                                     purpose of
                                                                     demonstrating
                                                                     compliance.
                                                                     Information shall
                                                                     include descriptions
                                                                     of:.
                                                                     Process or
                                                                     product in which the
                                                                     substitute is
                                                                     needed;
                                                                     Substitutes
                                                                     examined and
                                                                     rejected;
                                                                     Reason for
                                                                     rejection of other
                                                                     alternatives, e.g.,
                                                                     performance,
                                                                     technical or safety
                                                                     standards; and/or
                                                                     Anticipated
                                                                     date other
                                                                     substitutes will be
                                                                     available and
                                                                     projected time for
                                                                     switching.
Extruded Polystyrene:           Blends with       Acceptable        Acceptable from
 Boardstock and Billet.          maximum of 51     Subject to        [insert date 30 days
                                 percent HFC-      Narrowed Use      after date of
                                 134a, 17 to 41    Limits.           publication of final
                                 percent HFC-                        rule] until January
                                 152a, up to 20                      1, 2023 only for use
                                 percent CO2 and                     where reasonable
                                 one to 13                           efforts have been
                                 percent water.                      made to ascertain
                                                                     that other
                                                                     alternatives are not
                                                                     yet technically
                                                                     feasible for reasons
                                                                     of performance or
                                                                     safety.
                                                                    Users are required to
                                                                     document and retain
                                                                     the results of their
                                                                     technical
                                                                     investigation of
                                                                     alternatives for the
                                                                     purpose of
                                                                     demonstrating
                                                                     compliance.
                                                                     Information shall
                                                                     include descriptions
                                                                     of:.
                                                                     Process or
                                                                     product in which the
                                                                     substitute is
                                                                     needed;
                                                                     Substitutes
                                                                     examined and
                                                                     rejected;

                                                                     Reason for
                                                                     rejection of other
                                                                     alternatives, e.g.,
                                                                     performance,
                                                                     technical or safety
                                                                     standards; and/or
                                                                     Anticipated
                                                                     date other
                                                                     substitutes will be
                                                                     available and
                                                                     projected time for
                                                                     switching.
----------------------------------------------------------------------------------------------------------------

[FR Doc. 2021-21031 Filed 10-5-21; 8:45 am]
BILLING CODE 6560-50-P