[Federal Register Volume 77, Number 109 (Wednesday, June 6, 2012)]
[Rules and Regulations]
[Pages 33315-33331]
[FR Doc No: 2012-13189]

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 82

[EPA-HQ-OAR-2004-0488; FRL-9668-8]
RIN 2060-AM54

Protection of Stratospheric Ozone: Alternative for the Motor
Vehicle Air Conditioning Sector Under the Significant New Alternatives
Policy (SNAP) Program

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

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SUMMARY: Pursuant to the U.S. Environmental Protection Agency (EPA)'s
Significant New Alternatives Policy (SNAP) program, this action lists
carbon dioxide (CO2) or R-744, as acceptable substitute,
subject to use conditions, in the motor vehicle air conditioning (MVAC)
end-use for motor vehicles (i.e., passenger cars, light-duty and heavy-
duty vehicles) within the refrigeration and air-conditioning sector.
This final rule only concerns the use of CO2 in MVAC systems
designed specifically for the use of CO2 refrigerant. The
substitute is non-ozone-depleting and therefore does not contribute to
stratospheric ozone depletion.

DATES: This final rule is effective on August 6, 2012. The
incorporation by reference of a certain publication listed in this rule
is approved by the Director of the Federal Register as of May 31, 2011.

ADDRESSES: EPA has established a docket for this action under Docket ID
No. EPA-HQ-OAR-2004-0488. All documents in the docket are listed on the
www.regulations.gov Web site. Although listed in the index, some
information is not publicly available, e.g., confidential business
information (CBI) or other information whose disclosure is restricted
by statute. Certain other material, such as copyrighted material, is
not placed on the Internet and will be publicly available only in hard
copy form. Publicly available docket materials are available either
electronically through www.regulations.gov or in hard copy from the EPA
Air and Radiation Docket, EPA/DC, EPA West, Room 3334, 1301
Constitution Ave. NW., Washington, DC. This 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 Air and Radiation Docket is
(202) 566-1742.

FOR FURTHER INFORMATION CONTACT: Yaidi Cancel, Stratospheric Protection
Division, Office of Air and Radiation, MC 6205J, Environmental
Protection Agency, 1200 Pennsylvania Ave. NW., Washington, DC 20460;
telephone number:<PHONE_NUMBER>; fax number:<PHONE_NUMBER>; email
address<EMAIL_ADDRESS>
SUPPLEMENTARY INFORMATION: This final action provides motor vehicle
manufacturers and their suppliers with a refrigerant option subject to
use conditions for motor vehicle air conditioning systems for use in
new vehicles. The refrigerant discussed in this action, carbon dioxide
(R-744, CO2) is non-ozone-depleting and has a global warming
potential (GWP) \1\ of 1.
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    \1\ GWP, is defined as the ratio of heat trapped by one unit
mass of the greenhouse gas to that of one unit mass of
CO2 over a specified period of time. Consistent with the
international standards under the United Nations Framework
Convention on Climate Change (UNFCCC), all GWPs in this rule are
given using a 100-year period (IPCC, 1996).
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Table of Contents

I. Does this action apply to me?
II. What abbreviations and acronyms are used in this action?
III. How does the SNAP program work?
    A. What are the statutory requirements and authority for the
SNAP program?
    B. What are EPA's regulations implementing section 612 of the
Clean Air Act?
    C. How do the regulations for the SNAP program work?
    D. Where can I get additional information about the SNAP
program?
IV. What is EPA's final decision for CO2 as an
alternative for MVAC?
V. Why is EPA establishing these final use conditions for the use of
CO2 in MVAC?

VI. Why is EPA listing CO2 acceptable subject to use
conditions?
VII. What is the relationship between this SNAP rule and other EPA
rules?
VIII. What is EPA's response to public comments on the proposal?
    A. Use Conditions
    B. Risk Mitigation Strategies
    C. Industry Standards
    D. Servicing
IX. 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: Constitution and Coordination With
Indian Tribal Governments
    G. Executive Order 13045: Protection of Children From
Environmental Health Risks and Safety Risks
    H. Executive Order 13211: Actions That Significantly Affect
Energy Supply, Distribution, or Use
    I. National Technology Transfer Advancement Act
    J. Executive Order 12898: Federal Actions to Address
Environmental Justice in Minority Populations and Low-Income
Populations
    K. Congressional Review Act
X. References

I. Does this action apply to me?

    This final rule lists carbon dioxide (CO2)\2\, also
known as R-744, as an acceptable substitute subject to use conditions
for use as a refrigerant in new motor vehicle air conditioning (MVAC)
systems designed specifically for the use of CO2 refrigerant
in motor vehicles\3\. Businesses in this end-use that may want to use
CO2 in MVAC systems include:
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    \2\ Chemical Abstracts Service [CAS] Registry: No. 124-38-9.
    \3\ This final action applies only to air conditioning systems
in motor vehicles consistent with the definition of light duty
vehicles and heavy-duty vehicles under 40 CFR 86.1803-01, with the
exception of passenger busses.
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     Motor vehicle manufacturers
     Motor vehicle air conditioning service and repair shops
    Regulated entities may include:

    Table 1--Potentially Regulated Entities, by North American Industrial Classification System (NAICS) Code
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            Category                     NAICS code                   Description of regulated entities
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Industry.......................     336111, 336112, 336120  Motor Vehicle Manufacturing.
Services.......................                     811198  Vehicle Air Conditioning Repair.
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    This table is not intended to be exhaustive, but rather a guide
regarding entities likely to be regulated by this action. If you have
any questions about whether this action applies to a particular entity,
consult the person listed in the preceding section, FOR FURTHER
INFORMATION CONTACT.

II. What abbreviations and acronyms are used in this action?

ACGIH--American Conference of Governmental Industrial Hygienists
ASE--National Institute for Automotive Service Excellence
CAA--Clean Air Act
CAS--Chemical Abstracts Service
CBI--confidential business information
CFC--chlorofluorocarbon
CFC-12--the chemical dichlorodifluoromethane, CAS Reg. No. 75-71-8
CFD--computational fluid dynamics
CFR--Code of Federal Regulations
CNS--central nervous system
CO2--carbon dioxide, CAS Reg. No. 124-38-9, also known as
R-744
CRP--Cooperative Research Program
EPA--the United States Environmental Protection Agency
EO--Executive Order
FMEA--Failure Mode and Effect Analysis
FR--Federal Register
FTA--fault-tree analysis
GWP--Global warming potential
HCFC-22--the chemical chlorodifluoromethane, CAS Reg No. 75-45-6
HCFC-142b--the chemical 1-chloro-1,1-difluoroethane, CAS Reg No. 75-
68-3
HFC--hydrofluorocarbon
HFC-134a--the chemical 1,1,1,2-tetrafluoroethane, CAS Reg. No. 811-
97-2
HFC-152a--the chemical 1,1-difluoroethane, CAS Reg. No. 75-37-6
HFO--hydrofluoroolefin
HFO-1234yf--the chemical 2,3,3,3-tetrafluoroprop-1-ene, CAS Reg. No.
754-12-1
IDLH--Immediately Dangerous to Life and Health
MVAC--motor vehicle air conditioning
NIOSH--National Institute for Occupational Safety and Health
NODA--Announcement of Data Availability, formerly known as Notice of
Data Availability
NPRM--Notice of Proposed Rulemaking
NTTAA--National Technology Transfer and Advancement Act
ODP--ozone depletion potential
ODS--ozone-depleting substance
OEM--original equipment manufacturer
OMB--the United States Office of Management and Budget
OSHA--the United States Occupational Safety and Health
Administration
PEL--Permissible Exposure Level
ppm--parts per million
RDECOM--U.S. Army Research, Development and Engineering Command
REL--Recommended Exposure Level
RFA--Regulatory Flexibility Act
SAE--SAE International, formerly the Society of Automotive Engineers
SAE CRP--SAE Cooperative Research Program
SBREFA--Small Business Regulatory Enforcement Fairness Act
SNAP--Significant New Alternatives Policy
STEL--Short Term Exposure Limit
TWA--Time Weighted Average
UMRA--Unfunded Mandates Reform Act

III. How does the SNAP program work?

A. What are the statutory requirements and authority for the SNAP
program?

    Section 612 of the Clean Air Act (CAA) requires U.S. Environmental
Protection Agency (EPA) to develop a program for evaluating
alternatives to ozone-depleting substances (ODS). EPA refers to this
program as the Significant New Alternatives Policy (SNAP) program. The
major provisions of section 612 are:
1. Rulemaking
    Section 612(c) requires EPA to promulgate rules making it unlawful
to replace any class I (i.e., chlorofluorocarbon, halon, carbon
tetrachloride, methyl chloroform, methyl bromide, and
hydrobromofluorocarbon) or class II (i.e., hydrochlorofluorocarbon)
substance with any substitute that the Administrator determines may
present adverse effects to human health or the environment where the
Administrator has identified an alternative that (1) reduces the
overall risk to human health and the environment, and (2) is currently
or potentially available.
2. Listing of Unacceptable/Acceptable Substitutes
    Section 612(c) requires EPA to publish a list of the substitutes
unacceptable for specific uses and to publish a corresponding list of
acceptable alternatives for specific uses. The list of acceptable
substitutes is

found at http://www.epa.gov/ozone/snap/lists/index.html and the lists
of ``unacceptable,'' ``acceptable subject to use conditions,'' and
``acceptable subject to narrowed use limits'' substitutes are found in
the appendices to 40 CFR part 82 subpart G.
3. Petition Process
    Section 612(d) grants the right to any person to petition EPA to
add a substance, add or delete use restrictions, or delete a substance
from the lists published in accordance with section 612(c). The Agency
has 90 days to grant or deny a petition. Where the Agency grants the
petition, EPA must publish the revised lists within an additional six
months.
4. 90-Day Notification
    Section 612(e) directs EPA to require any person who produces a
chemical substitute for a class I substance to notify the Agency not
less than 90 days before new or existing chemicals are introduced into
interstate commerce for significant new uses as substitutes for a class
I substance. The producer must also provide the Agency with the
producer's unpublished health and safety studies on such substitutes.
5. Outreach
    Section 612(b)(1) states that the Administrator shall seek to
maximize the use of federal research facilities and resources to assist
users of class I and II substances in identifying and developing
alternatives to the use of such substances in key commercial
applications.
6. Clearinghouse
    Section 612(b)(4) requires the Agency to set up a public
clearinghouse of alternative chemicals, product substitutes, and
alternative manufacturing processes that are available for products and
manufacturing processes which use class I and II substances.

B. What are EPA's regulations implementing section 612 of the Clean Air
Act?

    On March 18, 1994, EPA published the original rulemaking (59 FR
13044) which established the process for administering the SNAP program
and issued EPA's first lists identifying acceptable and unacceptable
substitutes in the major industrial use sectors (40 CFR part 82,
subpart G). These sectors include: refrigeration and air conditioning;
foam blowing; solvents cleaning; fire suppression and explosion
protection; sterilants; aerosols; adhesives, coatings and inks; and
tobacco expansion. These sectors comprise the principal industrial
sectors that historically consumed the largest volumes of ODS.
    Section 612 of the CAA requires EPA to list as acceptable those
substitutes that do not present a significantly greater risk to human
health and the environment as compared with other substitutes that are
currently or potentially available.

C. How do the regulations for the SNAP program work?

    Under the SNAP regulations, anyone who produces a substitute to
replace a class I or II ODS in one of the eight major industrial use
sectors must provide notice to the Agency, including health and safety
information on the substitute at least 90 days before introducing it
into interstate commerce for significant new use as an alternative. 40
CFR 82.176(a). This requirement applies to the person planning to
introduce the substitute into interstate commerce,\4\ typically
chemical manufacturers, but may also include importers, formulators,
equipment manufacturers, or end-users\5\ when they are responsible for
introducing a substitute into commerce. The 90-day SNAP review process
begins once EPA receives the submission and determines that the
submission includes complete and adequate data. 40 CFR 82.180(a). The
CAA and the SNAP regulations, 40 CFR 82.174(a), prohibit use of a
substitute earlier than 90 days after notice has been provided to the
Agency.
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    \4\ As defined at 40 CFR 82.104 ``interstate commerce'' means
the distribution or transportation of any product between one state,
territory, possession or the District of Columbia, and another
state, territory, possession or the District of Columbia, or the
sale, use or manufacture of any product in more than one state,
territory, possession or District of Columbia. The entry points for
which a product is introduced into interstate commerce are the
release of a product from the facility in which the product was
manufactured, the entry into a warehouse from which the domestic
manufacturer releases the product for sale or distribution, and at
the site of United States Customs clearance.
    \5\ As defined at 40 CFR 82.172 ``end-use'' means processes or
classes of specific applications within major industrial sectors
where a substitute is used to replace an ozone-depleting substance.
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    The Agency has identified four possible decision categories for
substitutes: acceptable; acceptable subject to use conditions;
acceptable subject to narrowed use limits; and unacceptable.\6\ 40 CFR
82.180(b).Use conditions and narrowed use limits are both considered
``use restrictions'' and are explained below. Substitutes that are
deemed acceptable with no use restrictions (no use conditions or
narrowed use limits) can be used for all applications within the
relevant end-uses within the sector. Substitutes that are acceptable
subject to use restrictions may be used only in accordance with those
restrictions.
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    \6\ The SNAP regulations also include ``pending,'' referring to
submissions for which EPA has not reached a determination, under
this provision.
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    After reviewing a substitute, the Agency may determine that a
substitute is acceptable only if certain conditions in the way that the
substitute is used are met to minimize risks to human health and the
environment. EPA describes such substitutes as ``acceptable subject to
use conditions.'' Entities that use these substitutes without meeting
the associated use conditions are in violation of section 612 of the
Clean Air Act and EPA's SNAP regulations. 40 CF 82.174(c).
    For some substitutes, the Agency may permit a narrow range of use
within an end-use or sector. For example, the Agency may limit the use
of a substitute to certain end-uses or specific applications within an
industry sector. The Agency requires a user of a narrowed use
substitute to demonstrate that no other acceptable substitutes are
available for their specific application by conducting comprehensive
studies. EPA describes these substitutes as ``acceptable subject to
narrowed use limits.'' A person using a substitute that is acceptable
subject to narrowed use limits in applications and end-uses that are
not consistent with the narrowed use limit is using these substitutes
in an unacceptable manner and is in violation of section 612 of the CAA
and EPA's SNAP regulations. 40 CFR 82.174(c).
    The Agency publishes its SNAP program decisions in the Federal
Register (FR). EPA publishes decisions concerning substitutes that are
deemed acceptable subject to use restrictions (use conditions and/or
narrowed use limits), or for substitutes deemed unacceptable, as
proposed rulemakings to allow the public opportunity to comment, before
publishing final decisions.
    In contrast, EPA publishes substitutes that are deemed acceptable
with no restrictions in ``notices of acceptability,'' rather than as
proposed and final rules. As described in the preamble to the rule
initially implementing the SNAP program (59 FR 13044; March 18, 1994),
EPA does not believe that rulemaking procedures are necessary to list
alternatives that are acceptable without restrictions because such
listings neither impose any sanction nor prevent anyone from using a
substitute.
    Many SNAP listings include ``comments'' or ``further information''
to provide additional information on substitutes. Since this additional
information is not part of the regulatory

decision, these statements are not binding for use of the substitute
under the SNAP program. However, regulatory requirements so listed are
binding under other regulatory programs. The ``further information''
classification does not necessarily include all other legal obligations
pertaining to the use of the substitute. While the items listed are not
legally binding under the SNAP program, EPA encourages users of
substitutes to apply all statements in the ``further information''
column in their use of these substitutes. In many instances, the
information simply refers to sound operating practices that have
already been identified in existing industry and/or building-codes or
standards. Thus, many of the statements, if adopted, would not require
the affected user to make significant changes in existing operating
practices.

D. Where can I get additional information about the SNAP program?

    For copies of the comprehensive SNAP lists of substitutes or
additional information on SNAP, refer to EPA's Ozone Depletion Web site
at www.epa.gov/ozone/snap/index.html. For more information on the
Agency's process for administering the SNAP program or criteria for
evaluation of substitutes, refer to the SNAP final rulemaking published
March 18, 1994 (59 FR 13044), codified at 40 CFR part 82, subpart G. A
complete chronology of SNAP decisions and the appropriate citations are
found at http://www.epa.gov/ozone/snap/chron.html.

IV. What is EPA's final decision for CO2 as an alternative
for MVAC?

    In this final rule, EPA is modifying its previous determination
that listed CO2 as an acceptable substitute for CFC-12 in
new MVAC systems (59 FR 13044; March 18, 1994) and is listing
CO2 acceptable, subject to use conditions, as a substitute
for CFC-12 in new MVAC systems. This final action does not apply to the
use of CO2 as a conversion or retrofit for existing MVAC
systems. In addition, it does not apply to the use of CO2 in
the air conditioning or refrigeration systems of buses, trains, rail or
subway cars, or appliances such as refrigerated transport. This
refrigerant may be used only in equipment designed specifically and
clearly identified for this refrigerant (i.e., it may not be used as a
conversion or ``retrofit'' refrigerant for existing equipment). EPA is
not mandating the use of CO2 or any other alternative to ODS
in MVAC systems. Vehicle manufacturers have the option of using any
refrigerant listed as acceptable for this end-use, so long as they meet
the applicable use conditions. This action removes CO2 from
the list of acceptable substitutes for MVAC systems and instead lists
it as acceptable subject to the following use conditions:
    1. Engineering strategies and/or mitigation devices shall be
incorporated such that in the event of refrigerant leaks the resulting
CO2 concentrations do not exceed:
     The short term exposure level (STEL) of 3% or 30,000 ppm
averaged over 15 minutes in the passenger free space; and
     The ceiling limit of 4% or 40,000 ppm in the passenger
breathing zone.
    2. Vehicle manufacturers (i.e., original equipment manufacturers
[OEMs]) must keep records of the tests performed for a minimum period
of three years demonstrating that CO2 refrigerant levels do
not exceed the STEL of 3% averaged over 15 minutes in the passenger
free space, and the ceiling limit of 4% in the breathing zone.
    3. The use of CO2 in MVAC systems must adhere to the
standard conditions identified in SAE\7\ Standard J639 (2011 version)
including:
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    \7\ SAE International, formerly the Society of Automotive
Engineers.
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     Installation of a high pressure system warning label;
     Installation of a compressor cut-off switch; \8\ and
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    \8\ A compressor cut-off switch causes a device to stop
compressor operation before activation of any pressure relief
device.
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     Use of unique fittings with:
    i. Outside diameter of 16.6 +0/-0.2 mm (0.6535 +0/-0.0078 inches)
for the MVAC low-side service port;
    ii. Outside diameter of 18.1 +0/-0.2 mm (0.7126 +0/-0.0078 inches)
for the MVAC high-side service port; and
    iii. Outside diameter of 20.955 +0/-0.127 mm (0.825 +0/-0.005
inches) and right-hand thread direction for CO2 refrigerant
service containers.\9\
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    \9\ The refrigerant service containers fitting requirement
applies only to refrigerant service containers used during servicing
of the MVAC, in accordance with the provisions established for MVAC
servicing under 40 CFR part 82, subpart B.
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    To help ensure that the first use condition is met, we are
including several recommendations in the listing decision. First, OEMs
should conduct and keep on file Failure Mode and Effect Analysis (FMEA)
on the MVAC as stated in SAE J1739 (Potential Failure Mode and Effects
Analysis in Design [Design FMEA], Potential Failure Mode and Effect
Analysis in Manufacturing and Assembly Process [Process FMEA]), or
equivalent. Second, OEMs should factor in background CO2
concentrations that come about from normal respiration by the maximum
number of vehicle occupants.\10\ Third, EPA recommends the use of the
following industry standards as additional references when locating the
driver's and passengers' breathing zone consistent with the head and
seating position, measuring refrigerant concentrations at different
locations inside the passenger compartment including the breathing
zone, and addressing risks associated with MVAC use:
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    \10\ Maximum number of vehicle occupants includes the maximum
number of passengers in a normal seating position inside the
passenger compartment. This may vary between vehicle types.
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     SAE J1052--Motor Vehicle Driver and Passenger Head
Position;
     SAE J2772--Measurement of Passenger Compartment
Refrigerant Concentrations under System Refrigerant Leakage Conditions;
and
     SAE J2773--Standard for Refrigerant Risk Analysis for
Mobile Air Conditioning Systems.
    Fourth, EPA recommends additional training for MVAC service
technicians that will service MVAC systems using CO2 as the
refrigerant.

V. Why is EPA establishing these final use conditions for the use of
CO2 in new MVAC?

Summary of SNAP Actions on the Use of CO2 as a Refrigerant
in MVAC

    In the initial SNAP rulemaking issued on March 18, 1994 (59 FR
13044), EPA found CO2 acceptable as a substitute for CFC-12
in new MVAC systems. In that final rule, EPA also found other
substitutes (i.e., HFC-134a and R-401C, evaporative cooling and
stirring cycle) acceptable for use in new MVAC systems. On June 13,
1995 (60 FR 31092) and October 16, 1996 (61 FR 54040) EPA took two
separate actions requiring the use of unique fittings for several
refrigerants then currently listed as acceptable for use in new MVAC
systems (60 FR 31092) and for refrigerants subsequently found
acceptable for use in MVAC (61 FR 54040). The use conditions requiring
unique fittings were codified at 40 CFR Part 82, Subpart G, Appendix D.
None of these actions applied to CO2. However, in the
preamble to the October 16, 1996 SNAP rule, EPA stated that for any
decision made under SNAP, the Agency may, on its own, determine that
additional conditions or restrictions should be added or removed
through future rulemaking (61 FR 54032). Also, EPA stated in the
October 16, 1996 SNAP rule that due concerns about potential cross-
contamination as a result of the large number of MVAC refrigerants, the
Agency may choose to list a substitute as acceptable subject to

use the conditions listed (in that rule, i.e., use of unique fittings)
while proceeding with notice-and-comment rulemaking to impose other
restrictions (61 FR 54034).
    Although the initial SNAP rulemaking listed CO2 as
acceptable for use in new MVAC systems, at that time, EPA was not aware
of any interest in using CO2 in MVAC systems and did not
receive any submission for unique fittings to be used on CO2
MVAC systems or any information specified in 40 CFR Part 82, Subpart G,
Appendix D. EPA was subsequently made aware through risk screens of
concerns regarding health risks to exposure of CO2 from
refrigerant leaks into the passenger compartment (EPA-HQ-OAR-2004-0488-
0025.2). EPA was also made aware of potential interest in using
CO2 as a refrigerant for MVAC systems and of technology
being developed (71 FR 55141; September 21, 2006). On September 21,
2006, we issued a Notice of Proposed Rulemaking (referred to
hereinafter as ``the proposal'' or NPRM) proposing to find
CO2 acceptable as a substitute for CFC-12 in new MVAC
systems, subject to the use conditions specified at 40 CFR part 82,
subpart G, appendix D (71 FR 55140). In addition, due to concerns
regarding the possibility of driver performance decrement and adverse
effects on passengers if exposed to concentrations of CO2
above 3% during a short period of time (e.g., 15 minutes), we proposed
use conditions restricting CO2 refrigerant concentrations to
a STEL of 3% averaged over 15 minutes in the passenger free space
caused by leaks from the MVAC.\11\ Subsequently, on September 17, 2009
(74 FR 47774), EPA issued a notice of data availability (NODA) making
available to the public additional information received supporting a
ceiling limit of 4% CO2 as a level that should not be
exceeded for any period of time due to possible adverse health effects.
We also requested public comment on whether EPA should include in a
final rule, listing CO2 as acceptable subject to use
conditions for new MVAC systems, a ceiling limit of 4% CO2
in addition to the proposed STEL of 3% averaged over 15 minutes inside
the passenger compartment, and whether the proposed use conditions
should apply when the ignition is off.
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    \11\ In the same NPRM, EPA also proposed to find HFC-152a
acceptable subject to use conditions. On June 12, 2008, EPA
published a final rule listing HFC-152a as an acceptable substitute,
subject to use conditions, for new MVAC (73 FR 33304), but deferred
final ruling on the use of CO2 in new MVAC systems.
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Basis for Use Conditions Included in This Final Rule

    EPA proposed three use conditions in the NPRM. One use condition
required that systems be designed to avoid occupant exposure to
CO2 concentrations above a STEL of 3% CO2
averaged over 15 minutes in the passenger free space, during the event
of a leak. The passenger free space is the space inside the passenger
compartment excluding the space enclosed by the ducting in the HVAC
module (71 FR 55149). The proposal also stated that a breathing zone
ceiling limit may provide additional assurance regarding vehicle driver
alertness and requested comment on whether a maximum limit should be
applied in the driver and passenger breathing zone, in addition to the
3% CO2 free space limit averaged over 15 minutes. In the
NODA, we defined the breathing zone as the space where people breathe
(74 FR 47775), and data received during the public comment period
defined this zone as the area inside the passenger compartment where
the driver's and passengers' heads are located during a normal sitting
position.\12\
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    \12\ This was the location considered in the U.S. Army risk
assessment, in addition to the rest of the vehicle occupant
compartment (EPA-HQ-OAR-2004-0488-0025.2)
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    The other proposed use conditions required OEMs to: (1) Keep
records of the test performed to ensure that MVAC systems are safe and
designed with sufficient safety mitigation devices so that occupants
are not exposed to levels above the CO2 STEL; and (2) adhere
to all the safety requirements listed in the SAE Standard J639, in
addition to the use conditions already established under Appendix D to
Subpart G of 40 CFR part 82, for MVAC substitutes: unique fittings,\13\
label, and a compressor cut-off switch.
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    \13\ The unique fittings provision applies for MVAC service
ports and containers intended for servicing of the MVAC (Appendix D
to Subpart G of 40 CFR part 82, 61 FR 54040; October 16, 2006).
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    We received a number of public comments on the proposed use
conditions and subsequent data announced in the NODA regarding the 4%
CO2 ceiling limit. Some commenters claimed that the proposed
STEL of 3% CO2 averaged over 15 minutes was enough to
protect passengers and ensure driver alertness (EPA-HQ-OAR-2004-0448-
0025.1, -0032, -0044). Other commenters stated that there are
sufficient arguments for choosing percent concentration limits higher
than the proposed STEL of 3% CO2 averaged over 15 minutes
(EPA-HQ-OAR-2004-0448-0043, -0049). Alternatively, some commenters
requested a maximum CO2 ceiling limit in the passenger
breathing zone (EPA-HQ-OAR-2004-0448-0030, -0035, -0047.1) and one
commenter considered appropriate the 4% CO2 ceiling limit as
an additional use condition (EPA-HQ-OAR-2004-0448-0047.1).
    After considering the information in the docket at the time of
proposal, comments received on the proposed rule, and additional
information we have received in response to the NODA, we have decided
to finalize the use conditions as proposed in the September 21, 2006,
NPRM, and to add a ceiling limit of 4% CO2, which would
apply in addition to the 3% averaged over 15-minute CO2
STEL. We believe that requiring a CO2 ceiling limit is
necessary because it is possible for a time-weighted average
concentration, such as the STEL, to be under 3%, while peak
concentrations could reach higher limits resulting in possible hearing
and vision effects that could distract and endanger a driver, or cause
other, potentially more severe adverse health effects (EPA-HQ-OAR-2004-
0488-0041). Thus, the proposed use condition requiring mitigation
strategies for MVAC systems, to prevent leaks of CO2
refrigerant reaching concentrations above 3% averaged over 15 minutes
inside the passenger compartment free space, may not be sufficient on
its own to protect drivers and passengers. This further protective
limit is necessary to ensure that overall risks to human health and the
environment from CO2 will be similar to or less than those
of other available refrigerants that EPA has already listed as
acceptable for MVAC.
    In the final rule, we also revised the proposed use condition on
recordkeeping to refer to the 4% ceiling limit. The September 21, 2006
NPRM proposed requiring OEMs to keep records demonstrating they have
met the use condition requiring safety mitigation devices to avoid
occupant exposure above the 3% CO2 STEL in the passenger
compartment. The final use condition addressing recordkeeping requires
OEMs to keep records of the tests performed for a minimum period of
three years demonstrating that MVAC systems are designed incorporating
engineering devices or mitigation strategies so that in the event of
refrigerant leak, the resulting concentrations of CO2 in the
passenger free space do not exceed the STEL of 3% averaged over 15
minutes and do not exceed the ceiling limit of 4% in the passenger
breathing zone. Keeping records of tests performed evaluating system
safety is a customary practice for OEMs while vehicles are in
production

and for several years afterward (EPA-HQ-OAR-2004-0488-0057).
    For purposes of the final rule, we are referencing to the 2011
version of SAE J639 instead of the 2005 version referenced in the
proposed rule. The SAE J639 2011 version added new provisions designed
specifically to address use of another refrigerant, HFO-1234yf (EPA-HQ-
OAR-2004-0488-0059). The provisions under the 2011 version of SAE J639
for high pressure system warning label, compressor cut-off switch, and
unique fittings, remain unchanged. Consistent with the proposed rule,
the criteria for uniqueness of fittings under Appendix H to Subpart G
of 40 CFR Part 82, and the provisions of Appendix D to Subpart G of 40
CFR Part 82 and SAE J639 (2011 version), in this final rule we specify
that the CO2 refrigerant fittings must have: (1) An outside
diameter of 16.6 +0/-0.2 mm (0.6535 +0/-0.0078 inches) for the MVAC
low-side, (2) an outside diameter of 18.1 +0/-0.2 mm (0.7126 +0/-0.0078
inches) for the MVAC high-side, and (3) an outside diameter of 20.955
+0/-0.127 mm (0.825 +0/-0.005 inches) and right-hand thread direction
for refrigerant service containers.\14\
---------------------------------------------------------------------------

    \14\ The SAE J639 standard specifies unique fittings for high-
side and low-side service ports and makes reference to SAE J2683
``Refrigerant Purity and Container requirements for Carbon Dioxide
(CO2 R-744) Used in Mobile Air Conditioning Systems''
which specifies that the unique fitting for CO2
refrigerant service containers must be consistent with the Cylinder
Gas Association's fitting CGA 320 (for 0-3000 psi) which has an
outside diameter of 0.825 +0/-0.005 inches (20.955 +0/-0.127 mm) and
right-hand thread direction (EPA-HQ-OAR-2004-0488-0059, -0060).
---------------------------------------------------------------------------

VI. Why is EPA listing CO2 acceptable subject to use
conditions?

    EPA is listing CO2 acceptable subject to use conditions
because the use conditions are necessary to ensure that use of
CO2 will not present greater risk to human health and the
environment than other available substitutes acceptable for use in new
MVAC systems. Examples of other substitutes that EPA has already found
acceptable subject to use conditions for use in new MVAC systems
include HFC-152a and HFO-1234yf.\15\ A list of acceptable substitutes
subject to use conditions for use in new MVAC systems can be found at
Appendix B to Subpart G of 40 CFR, Part 82 and http://www.epa.gov/ozone/snap/refrigerants/lists/mvacs.html.
---------------------------------------------------------------------------

    \15\ HFO-1234yf was found acceptable only for MVAC systems in
new passenger cars and light duty trucks (76 FR 17488, March 29,
2011).
---------------------------------------------------------------------------

    EPA is requiring the use of unique fittings for CO2
refrigerant consistent with Appendix D to Subpart G of 40 CFR part 82
(61 FR 54040; October 16, 1996). All acceptable substitutes for use in
MVAC systems are subject to those use conditions (and thus are
identified as acceptable subject to use conditions). For
CO2, the unique fittings that must be used for MVAC systems
are those identified in the industry standard SAE J639 (2011 version).
    In addition to the use conditions regarding unique fittings, EPA is
requiring OEMs to adhere to all the safety requirements of SAE J639
(2011 version) for the safe design of new MVAC systems using
CO2. We are establishing this as a use condition to ensure
that new MVAC systems that use CO2 are specifically designed
to minimize release of the refrigerant into the passenger cabin.
Adherence to the standard will minimize the risks that CO2
refrigerant levels in the passenger compartment and breathing zone
would exceed the CO2 limits of 3% averaged over 15 minutes
in the passenger cabin free space and the 4% ceiling limit in the
passenger breathing zone.

Environmental Impacts

    EPA finds that CO2 does not pose greater risk to the
environment than other substitutes that are currently available in the
end-use being evaluated in this rulemaking. In at least one aspect,
CO2 is significantly better for the environment than most
alternatives currently listed as acceptable subject to use conditions
in the MVAC end-use. CO2 has a hundred-year time horizon
(100-yr) global warming potential (GWP) of one, compared with a GWP of
four for HFO-1234yf, 124 for HFC-152a, and 1,430 for HFC-134a. Further,
CO2 has an ozone depletion potential (ODP) of zero,
comparable to HFO-1234yf, HFC-152a, and HFC-134a. Other SNAP-approved
refrigerant blends containing HCFCs have ODPs ranging from 0.065 to
0.022. Additionally, CO2 is excluded from the definition of
volatile organic compound (VOC) under CAA regulations (see 40 CFR
51.100(s)).

Human Health and Safety Impacts

    Carbon dioxide is not flammable, similar to HFC-134a and most other
acceptable alternatives for MVACs. Therefore, it does not add risks of
fire in a vehicle when used. For the MVAC end-use, the EPA has listed
two flammable alternatives (HFC-152a and HFO-1234yf) acceptable,
subject to use conditions to mitigate flammability risks.
    CO2 is an asphyxiant that obstructs the oxygen flow into
the body (OSHA, 1996; as cited in EPA-HQ-OAR-2004-0488-0041). However,
it is not the only gas that may cause asphyxia. Releasing almost any
gas \16\ into an unventilated or poorly ventilated space can lower the
oxygen concentration to a level that poses significant health risks
(EPA-HQ-OAR-2004-0488-0041). Health risks could occur to drivers or
vehicle occupants during release of CO2 refrigerant into the
passenger compartment. Additionally, occupational risks could occur
during the manufacture of the refrigerant, initial installation of the
refrigerant into the MVAC system at the vehicle assembly plant,
servicing of the MVAC system, or final disposition of the MVAC system
(i.e., recycling or disposal).
---------------------------------------------------------------------------

    \16\ Any refrigerant can act as an asphyxiant by limiting
available oxygen in a space. When oxygen levels in air are reduced
to 12-14% by displacement, symptoms of asphyxiation, loss of
concentration, increased pulse rate and deeper respiration will
occur.
---------------------------------------------------------------------------

    We evaluated potential human health and safety impacts, including
the short- and long-term toxicity of CO2 and risk of injury
to service personnel from high-pressure CO2 MVAC systems,
and considered detailed risk assessments with fault-tree analysis
(FTA), (EPA-HQ-OAR-2004-0488-0017, -0022, and -0025.2), scientific data
provided in public comments (EPA-HQ-OAR-2004-0488-0037.1) and other
information obtained during the notice of data availability (EPA-HQ-
OAR-2004-0488-0041). We also reviewed a risk assessment with fault-tree
analysis from the SAE Corporate Research Program (CRP) for HFO-1234yf
and CO2, submitted during the public comment period for
another SNAP rulemaking \17\ (EPA-HQ-OAR-2004-0488-0051, EPA-HQ-OAR-
2008-0664-0008, and -0056). We also evaluated and provided additional
information on the health effects and risks to CO2 exposure
through a contractor-authored report ``Review of Health Impacts from
Short-Term Carbon Dioxide Inhalation Exposures'' (EPA-HQ-OAR-2004-0488-
0041). This report revealed that exposures over 4% (40,000 ppm)
CO2 are likely to cause discomfort and signs of intoxication
that could impair the driver's response to road and driving conditions,
and could create safety and health risks to the passengers. In addition
to this report, a revised risk analysis performed by the U.S. Army
Research, Development and Engineering Command (herein referred as U.S.
Army risk analysis),\18\ submitted during the

public comment period, indicated that limiting passenger exposure to 4%
CO2 is sufficiently protective to avoid serious or
irreversible health effects in potentially sensitive subpopulations
(EPA-HQ-OAR-2004-0488-0025.2). Also, the U.S. Army risk analysis
selected the 4% CO2 level based on the lowest level at which
performance decrements were observed in studies by Wong, 1992 (EPA-HQ-
OAR-2004-0488-0025.2).
---------------------------------------------------------------------------

    \17\ SNAP rule listing as acceptable subject to use conditions
HFO-1234yf for MVACs in new passenger cars and light-duty vehicles
(76 FR 17488, March 29, 2011).
    \18\ Blackwell et. al 2006; Risk Analysis for Alternative
Refrigerant in Motor Vehicle Air Conditioning (revised risk analysis
made in collaboration with EPA and several stakeholders, EPA-HQ-OAR-
2004-0488-0025.2). The original risk screen referred in the NRPM (71
FR 55140) contained technical errors (EPA-HQ-OAR-2004-0488-0017).
This final rule relies on the results of the revised U.S. Army risk
analysis.
---------------------------------------------------------------------------

Vehicle Driver and Passenger Risks

    EPA's review of vehicle driver and passenger risks from
CO2 refrigerant exposure indicated that a potential
refrigerant leak into the vehicle passenger compartment is not expected
to present an unreasonable exposure risk if engineering strategies or
mitigation strategies are applied (EPA-HQ-OAR-2004-0488-0025, -0037.1).
The U.S. Army risk assessment indicated a possible strategy to limit
refrigerant leakage into the passenger compartment by installing a
device referred as a ``3-second squib valve'' to discharge refrigerant
to a location outside the passenger compartment three seconds after a
major leak is detected.\19\ The assessment showed that for
CO2 MVAC systems, using a squib valve to evacuate the charge
in three seconds after a leak is detected kept passenger exposure to
below levels of concern (i.e., 3% over 15 minutes in the passenger
compartment, as a whole, and 4% in the breathing zone).We listed in the
proposal additional possible mitigation strategies that may reduce the
likelihood of exceeding refrigerant levels of concern inside the
passenger compartment, including within the breathing zone. We also
received information from commenters on additional engineering
strategies and mitigation strategies (EPA-HQ-OAR-2004-0488-0037.1, -
0025.2, -0030, -0050). In this final rule, we are not establishing a
use condition requiring a specific mitigation strategy, but instead
leaving to vehicle manufacturers the choice of which mitigation
strategy to use in order to ensure that in the event of refrigerant
leak, the resulting concentrations of CO2 in the passenger
free space above 3% or 30,000 ppm averaged over 15 minutes are avoided
and the resulting concentrations of CO2 in the passenger
breathing zone do not exceed the ceiling limit of 4% or 40,000 ppm at
any time.
---------------------------------------------------------------------------

    \19\ Refers to the assessment by Blackwell, et al., 2006 (EPA-
HQ-OAR-2004-0488-0025).
---------------------------------------------------------------------------

Occupational Risks

    EPA evaluated risks of injury and refrigerant exposure to workers
by examining risk screens, published research information and data made
available during the public comment period (EPA-HQ-OAR-2004-0017, -
0025.2, -0041, -0022, -0015, -0051). We compared long-term occupational
exposures to CO2 to a workplace exposure limit of 5,000 ppm
(or 0.5%) time weighted average CO2 concentration over a
period of eight hours, consistent with the Occupational Safety and
Health Administration (OSHA) Permissible Exposure Limit-Time Weighted
Average (PEL-TWA),\20\ the Centers for Disease Control and Prevention's
(CDC's) National Institute for Occupational Safety and Health (NIOSH)
Recommended Exposure Limit-Time Weighted Average (REL-TWA),\21\ and the
American Conference of Governmental Industrial Hygienists (ACGIH)
Threshold Limit Value-Time Weighted Average (TLV-TWA).22 23
Additionally, we compared short-term occupational worker exposures to
CO2 to a workplace short-term exposure limit of 30,000 ppm
(or 3%) time weighted average CO2 concentration over a 15-
minute period during a workday, consistent with NIOSH's Recommended
Exposure Limit-Short term Exposure Limit (REL-STEL) \24\ and ACGIH's
Threshold Limit Value-Short Term Exposure Limit (TLV-
STEL).25 26
---------------------------------------------------------------------------

    \20\ PELs are based on an eight hour TWA exposure (OSHA, 1988a).
    \21\ REL-TWAs are concentrations for up to 10-hour workday
during a 40-hour workweek (NIOSH, 2005).
    \22\ TLV-TWAs are concentrations for an eight hour workday and a
40-hour workweek, to which is believed that nearly all workers may
be repeatedly exposed, day after day, for a working lifetime without
adverse effect (ACGIH, 2005).
    \23\ OSHA's PEL-TWA, NIOSH's REL-TWA, and ACGIH'S TLV-TWA are
all the same, 5,000 ppm (0.5%), for CO2 (EPA-HQ-OAR-2004-
0488-0041).
    \24\ REL-STELs are 15-minute TWA exposure limits that should not
be exceeded at any time during a workday (NIOSH, 2005).
    \25\ TLV-STELs are 15-minute exposure that should not be
exceeded at any time during a workday, even if the eight hour TWA is
within the TLV-TWA (ACGIH, 2005).
    \26\ NIOSH's REL-STEL, and ACGIH'S TLV-STEL for CO2
are all 30,000 ppm (3%) 15-minute TWA (EPA-HQ-OAR-2004-0488-0041).
---------------------------------------------------------------------------

    The U.S. Army risk assessment (EPA-HQ-OAR-2004-0488-0025.2)
evaluated occupational risks for the MVAC service sector using FTA. The
FTA found probabilities of refrigerant exposure while servicing
CO2 MVAC systems of approximately 10-5 cases per
year (i.e., approximately 5 annual cases per 100,000 technicians) (EPA-
HQ-OAR-2004-0488-0025). This figure is significantly lower when
compared to the general injury and illness rate for auto repair
technicians, which is approximately 4 annual cases per 100 full time
technicians (BLS, 2003; EPA-HQ-OAR-2004-0488-0025); thus risks from
CO2 exposures in the MVAC service field are expected to be
significantly less than the risks of injury already present in shops
(EPA-HQ-OAR-2004-0488-0025). The U.S. Army risk assessment additionally
found that the chances of refrigerant exposure for persons servicing an
MVAC system do not vary considerably by the type of refrigerant used
and found similar results for end-of-life (i.e., recycling or disposal)
activities (EPA-HQ-OAR-2004-0488-0025).
    EPA notes that occupational risks could occur during the
manufacture of the refrigerant and initial installation of the
refrigerant into the MVAC system at the vehicle assembly plant.
Although we did not analyze the risk of exposure during refrigerant
manufacture and initial installation of CO2 refrigerant into
the MVAC system at the vehicle assembly plant, we expect risks at the
vehicle assembly plant, and at other workplaces were CO2
refrigerant handling will occur (e.g., service shops, and recycling or
disposal facilities), to be similar to or lower than the risks from
other refrigerants used for these purposes due to occupational safety
practices (e.g., proper ventilation, use of personal protective
equipment) established for these type of facilities and subject to
occupational safety and health standards under 29 CFR Part 1910, which
are intended to address risk to such workers.

Overall Conclusion

    EPA finds that the overall environmental and human health risks
posed by the use of CO2 in new MVAC systems, subject to the
use conditions being adopted in this final rule, is lower than or
comparable to the risks posed by other substitutes found acceptable
subject to use conditions in the same end-use.

VII. What is the relationship between this SNAP rule and other EPA
rules?

Rules Under Sections 609 and 608 of the Clean Air Act

    This final SNAP rule addresses the conditions for safe use of
CO2 in new MVAC systems. Thus, the requirements in this rule
apply primarily to OEMs, except for specific requirements for unique
fittings required under Appendix D to Subpart G of 40 CFR part 82 which
also applies for servicing of

the MVAC. Section 609 of the CAA establishes standards and requirements
regarding servicing of MVAC systems. These requirements include
training and certification of any person that services MVAC systems for
consideration,\27\ as well as standards for certification of equipment
for refrigerant recovery and recycling. EPA has issued regulations
implementing these statutory requirements and those regulations are
codified at subpart B of 40 CFR part 82. MVAC end-of-life disposal and
recycling specifications are covered under section 608 of the CAA and
our regulations are codified at subpart F of 40 CFR part 82. The
statutory and regulatory provisions regarding MVAC servicing,
refrigerant recovery, and refrigerant venting prohibition apply to any
refrigerant alternative and are not limited to refrigerants that are
also ODS. CO2 is exempted from the refrigerant venting
prohibition provisions promulgated under CAA 608 (40 CFR 82.154 and 70
FR 19278; April 13, 2005).
---------------------------------------------------------------------------

    \27\ Service for consideration means receiving something of
worth or value to perform service, whether in money, credit, goods,
or services (see 40 CFR 82.32 (g)).
---------------------------------------------------------------------------

VIII. What is EPA's response to public comments on the proposal?

    This section summarizes EPA's response to significant comments
received during the public comment periods for the NPRM and the NODA.
EPA's response to all comments received can also be found in a response
to comments document in docket EPA-HQ-OAR-2004-0488.

A. Use Conditions

    Comment: Some commenters claimed that the proposed STEL of 3%
CO2 averaged over 15 minutes in the cabin free space is
enough to protect passengers and ensure driver alertness. One commenter
suggested to consider a 3% CO2 concentration limit averaged
over 15 minutes in the breath level (i.e., breathing zone) instead of
3% in the cabin free space. The commenter considered the breathing zone
to be a relevant point for measurement and claimed that high
refrigerant concentrations lower in the vehicle would not impair
vehicle operation. Other commenters supported higher CO2
concentration limits but over a shorter period of time (e.g., 5.5%
CO2 for 5 minutes and 9% CO2 as a ceiling limit).
Other commenters requested that EPA include a CO2 ceiling
limit in the passenger breathing zone and one commenter considered
appropriate a 4% CO2 ceiling limit (i.e., a limit not to be
exceeded at any time) as an additional use condition. Another commenter
stated that use conditions requiring mitigation strategies are not
necessary for low probability events (i.e., exceeding 4% CO2
for any duration) and that requiring such conditions would prevent the
use of this refrigerant.
    Response: After evaluating the comments and risk screens (EPA-HQ-
OAR-2004-0488-0025.2, -0041, 0051), EPA is revising the proposed use
conditions to add a ceiling limit of 4% CO2, in addition to
the CO2 STEL of 3% averaged over 15 minutes. We believe that
the original proposed use condition requiring mitigation strategies for
MVAC systems, to prevent leaks of CO2 refrigerant reaching
concentrations above 3% averaged over 15 minutes inside the passenger
compartment free space, may not be sufficient on its own to protect
drivers and passengers. We also believe that requiring a CO2
ceiling limit of 4% is necessary because it is possible for a time-
weighted average concentration, such as the STEL, to be under 3%, while
peak concentrations could reach higher limits for a few minutes. As
shown in published data, CO2 concentration peaks above 4%
could result in effects on hearing and vision that could distract and
endanger a driver, or other, potentially more severe adverse health
effects (EPA-HQ-OAR-2004-0488-0041).
    CFD modeling showed that during unmitigated refrigerant leak
scenarios, CO2 refrigerant concentrations in the passenger
breathing zone can reach up to 10.2% in 50 seconds (0.83 minutes) and
8.0% in 200 seconds (3.33 minutes) (EPA-HQ-OAR-2004-0488-0025.2). The
U.S. Army risk analysis's FTA showed that unmitigated leak scenario
occurrences for CO2 systems (reaching concentrations above
4% CO2) could reach 4,300 per year for the vehicle fleet
(EPA-HQ-OAR-2004-0488-0025.2). These occurrences are about 10,000
higher than the expected occurrences associated with leaks of a
fluorinated refrigerant (e.g., HFC-134a, HFC-152a, or HFO-1234yf)
breakdown product (i.e., hydrogen fluoride) exposure above health based
limits.\28\ Several studies reported that exposure ranging from 7% to
10% CO2 for few minutes (e.g., 2-3 minutes) resulted in loss
of consciousness (EPA-HQ-OAR-2004-0488-0441).\29\
---------------------------------------------------------------------------

    \28\ The risk due to exposure to HF when using HFO-1234yf is
approximately the same as that with the current use of HFC-134a (on
order of 10-12 occurrences per operating hour, or one in
one trillion). (76 FR 17488; March 29, 2011). When this factor is
multiplied by the approximate vehicle fleet and annual vehicle
operating hours (250 million and 500 hr/yr, respectively) the
occurrences per year are in the order of 10-1.
    \29\ Unconsciousness caused by short term exposure (e.g., 2-3
minutes) of CO2 concentration ranging from 7 to 10% was
reported in studies by Aero Medical Association (1953), Flury and
Zernik (1931), Hunter (1975), Schaefer (1951), and NIOSH (1996), as
cited in Review of Health Impacts for Short-Term Carbon Dioxide
Inhalation Exposures (2009). EPA-HQ-OAR-2004-0488-0041.
---------------------------------------------------------------------------

    EPA disagrees with the commenter stating that use conditions
requiring mitigation strategies are not necessary for low probability
events and that requiring such conditions would prevent the use of this
refrigerant. Consistent with the information above, we believe that
unmitigated exposure occurrences are not rare. We believe the use
conditions required in this final rule are necessary to ensure that
overall risks to human health and the environment from CO2
will be similar to or less than those of other available refrigerants
that EPA has already listed as acceptable for MVAC. We also believe
that requiring the use conditions listed in this final rule would not
make the refrigerant use less practicable. Use conditions imposed on
other acceptable alternatives for MVACs (e.g., adherence to all safety
requirements under SAE standard J639, use of unique fittings and
labels, use of pressure relief devices) has not prevented use of such
alternatives.\30\
---------------------------------------------------------------------------

    \30\ On March 29, 2011, EPA issued a final rule listing HFO-
1234yf as acceptable subject to use conditions for MVACs in new
passenger car and light duty trucks. One of the use conditions in
that rule require OEMs to perform and keep on file an FMEA. In an
FMEA vehicle designers analyze all the ways in which parts of the
MVAC system could fail and identify how they will address those
risks in design of the system. (76 FR 17488). If the FMEA reports
that mitigation strategies are necessary in the MVAC for safety
reasons, manufacturers are required to design safety components
(e.g., mitigation strategies) to comply with the use condition of
that rule. In the U.S. an OEM publicly announced that it will be
using HFO-1234yf in some vehicles starting 2013 model year (EPA-HQ-
OAR-2004-0488-0062).
---------------------------------------------------------------------------

    Comment: Several commenters indicated that concentration
measurements of CO2 inside the passenger compartment should
consider passenger respiration in addition to a refrigerant leak from
the A/C system. Another commenter indicated that the MVAC recirculation
mode operates with at least 1% of fresh air. One commenter suggested
changing the text of the proposed use condition indicating the STEL for
CO2 refrigerant inside the passenger compartment to state
that the STEL is ``3% v/v fully-occupied-volume, time averaged over 15
minutes'' and to clarify that the calculation of such value is based on
a double average consisting of the average CO2 concentration
over the air volume of a fully occupied car and a time-average of

volume-average over 15 minutes.\31\ Another commenter suggested
alternative language for the use condition specifying a ceiling limit
of 4% CO2 applicable in any part of the free space inside
the passenger compartment for a time period of 60 seconds when the car
ignition is on. The suggested language reads:
---------------------------------------------------------------------------

    \31\ Fully occupied is defined as the maximum design occupancy
determined by the number of sets of seat belts (EPA-HQ-OAR-2004-
0488-0025.1--0025.2).
---------------------------------------------------------------------------

    ``Engineering strategies and/or devices shall be incorporated into
the system such that foreseeable leaks into the passenger compartment
do not result in R744 concentrations of 4.0% v/v or above in any part
of the free space inside the passenger compartment for more than 60
seconds when the car ignition is on.''
    Response: EPA notes that the U.S. Army risk analysis assumed that a
maximum number of passengers were in the vehicle before the release of
refrigerant into the passenger compartment, allowing for some build-up
of respiratory CO2 (EPA-HQ-OAR-2004-0488-0025.2). Thus, that
analysis recognized that CO2 concentrations can occur from
human respiration in a space with limited exchange of outside air and
may consequently build up in the passenger cabin. For that reason, in
the proposal, we indicated that OEMs should account for background
CO2 concentrations in the passenger compartment that can
result from human respiration when designing their systems and
mitigation devices (71 FR 55140; September 21, 2006). However, we did
not specify whether the vehicle should be fully occupied to account for
CO2 background concentrations. We believe that
CO2 refrigerant concentrations may reach levels of concern
(i.e., above 4% CO2) during an unmitigated event of
refrigerant leak either when the vehicle is fully occupied or when not
fully occupied (e.g., the vehicle is occupied by the driver only). Thus
we do not agree with the commenter's suggestion to state that the STEL
is ``3% v/v fully-occupied-volume, time averaged over 15 minutes''. In
this final rule, we recommend but do not require, consistent with the
NPRM, to account for background CO2 concentrations from
human respiration, in addition to refrigerant leaks when designing the
MVAC.
    EPA notes that the proposal (79 FR 55140; September 21, 2006)
specifies the CO2 STEL as a concentration limit averaged
over 15 minutes, in the event of a refrigerant leak. The STEL is
determined from the sum of concentration and exposure time products
(e.g., concentration 1 times exposure time 1 plus concentration 2 times
exposure time 2), divided by the total exposure time which shall not
exceed 15 minutes (EPA-HQ-OAR-2004-0448-0041). Thus the STEL is a time-
weighted average concentration and not necessarily a time-average of a
volume-average as indicated by the commenter since STEL refers to a
total exposure time (i.e., 15 minutes) and not an average time. For
this reason, we do not agree with the commenter's suggestion to clarify
that the calculation of the 3% STEL is based on a double average
consisting of the average CO2 concentration over the air
volume of a fully occupied car and a time-average of volume-average
over 15 minutes since the approach does not provide further clarity of
the use condition. In this final rule, the CO2 STEL of 3%
averaged over 15 minutes considers the average CO2
concentration in a passenger cabin over a total time period of 15
minutes during the event of refrigerant leak; and the ceiling limit of
4% CO2 considers the total CO2 in the passenger
breathing zone at any one moment in a passenger compartment during the
event of a leak.
    Regarding the alternative language suggested by the other commenter
specifying a ceiling limit of 4% CO2 applicable in any part
of the free space inside the passenger compartment for a time period of
60 seconds when the car ignition is on, we note that the commenter did
not provided information supporting his suggestion that the ceiling
limit apply in areas other than the passenger breathing zone for the
specified 60-second time period.
    Comment: Two commenters indicated the need for clarity on whether
the use conditions apply when the ignition is off as well as when the
ignition is on. Other commenters suggested considering the results of a
risk assessment performed by SAE's CRP indicating a significantly low
probability for a leak when the ignition is off, and several other
commenters stated that the use conditions should only apply when the
ignition is on.
    Response: The NODA provided data and requested additional comment
on whether the use conditions should apply when the engine is off. In
December, 2009, after the public comment period closed on the NODA, SAE
issued a report, ``Risk Assessment for HFO-1234yf and R-744
(CO2) Phase III'' (referred herein after as SAE CRP report),
that evaluated toxicity effects and quantitative risks of
CO2, similarly to the U.S. Army risk analysis. This report
was submitted to EPA during the public comment period for another SNAP
rulemaking.\32\ The report evaluates CO2 exposure
estimations due to leaks into the passenger compartment during
different modeled scenarios such as different MVAC operation mode,
system failure, and during a collision (EPA-HQ-OAR-2008-0664-0056.2,
EPA-HQ-OAR-2004-0488-0025.2, -0051). The SAE CRP report also evaluated
refrigerant release into the passenger compartment during a scenario
where the engine is expected to be off (EPA-HQ-OAR-2004-0488-0051, EPA-
HQ-OAR-2008-0664-0056.2). For this scenario, which involves passengers
sleeping inside a vehicle with the windows closed while refrigerant
leaks occur, the SAE CRP report showed a probability for occurrences of
CO2 refrigerant exposure above 6% (a threshold limit used by
the CRP for this scenario) to be in the order of 10-12 per
vehicle/hour/occupant (EPA-HQ-OAR-2004-0488-0051, EPA-HQ-OAR-2008-0664-
0056.2). We believe that exposures of concern inside the passenger
compartment are more likely to result from a large, sudden release of
refrigerant inside the passenger compartment and that such a situation
is most likely during a collision while the ignition is on, as
described on the U.S. Army risk analysis (EPA-HQ-OAR-2004-0488-0025.2)
and consistent with the SAE CRP report (EPA-HQ-OAR-2004-0488-0051, EPA-
HQ-OAR-2008-0664-0056.2). In addition, even if a rupture on the
evaporator line is large, the overall leak rate is limited to the
maximum flow rate of refrigerant through the fixed orifice tube opening
of the MVAC (EPA-HQ-OAR-2004-0488-0025.2). The maximum flow rate is
determined by the differential compressor discharge pressure, which is
only available when the vehicle ignition is on and MVAC system is
running. Therefore, EPA finds that the overall risks to human health
and the environment from CO2 will be similar to or less than
those of other available refrigerants that EPA has already listed as
acceptable for MVAC when the ignition is off. Thus, consistent with a
SNAP rule issued in June 12, 2008 (73 FR 33304) listing HFC-152a \33\
as acceptable subject to use conditions for use in new MVAC systems,
the use

conditions in this final rule apply only when the ignition is on.
---------------------------------------------------------------------------

    \32\ We refer here to the SNAP rule listing HFO-1234yf as
acceptable subject to use conditions for MVACs in new passenger cars
and light duty vehicles (EPA-HQ-OAR-2008-0644, 74 FR 17488; March
29, 2011).
    \33\ HFC-152a poses risks comparable to CO2 and other
available refrigerants found acceptable subject to use conditions
under SNAP (73 FR 33304; June 12, 2008).
---------------------------------------------------------------------------

    Comment: One commenter suggested that the regulation should
precisely define the area in the vehicle being regulated and indicated
that SAE is working on a standard to establish standards for passenger
compartment refrigerant concentration measurement. Another commenter
indicated that a CO2 concentration limit should focus on the
driver breathing zone rather than the cabin free space.
    Response: EPA has clarified the regulatory text of the use
condition to define the passenger free space as the space inside the
passenger compartment, excluding the space enclosed by the ducting in
the HVAC module. The passenger breathing zone, where the ceiling limit
of 4% must be met, is defined as the area inside the passenger
compartment where the driver's and passengers' heads are located during
normal sitting position (i.e., space where people breathe, as defined
in the NODA (71 FR 47775; September 17, 2009)). Additionally, we note
that the passenger breathing zone is defined in SAE J2772 and the
driver's head position in SAE J1052. Since the automotive industry
often relies on standards for designs and assessments, we recommend the
use of the SAE J1052 and SAE J2772 standards as references for further
specifications regarding the driver's and passengers' head and seating
position and to establish the passenger breathing zone consistent with
our explanation provided in Section V of the preamble (i.e., the area
inside the passenger compartment where the driver's and passengers'
heads are located during a normal sitting position).
    EPA disagrees with the comment indicating that a CO2
concentration limit should only focus on the driver breathing zone
rather than the passenger cabin free space. Based on the risk analyses
and available data, we include in this final rule a 4% ceiling limit
that must not be surpassed at any time in the passenger (and driver)
breathing zone (EPA-HQ-OAR-2004-0488-0044-0025.2). We also include, as
proposed, a 3% CO2 STEL averaged over 15 minutes in the
passenger cabin free space as an additional protective measure for
passenger exposure to CO2. As indicated by the U.S. Army
risk assessment, sensitive subpopulations (e.g., elderly and children)
may be affected from exposures to high concentrations of CO2
(EPA-HQ-OAR-2004-0488-0025.2), thus we believe it is necessary to set a
limit that would address risk to all people in the passenger
compartment and not solely the driver. We also take into consideration
that passengers may not be in a normal sitting position all the time
(e.g., passenger may rest in a reclined position) and note
CO2 is heavier than air, thus higher concentrations may be
found at lower points of the passenger cabin (EPA-HQ-OAR-2004-0488-
0025.2, -0041, -0051). As indicated previously, the STEL is the
concentration limit that people can be exposed continuously for a short
period of time (i.e., 15 minutes) without suffering adverse health
risks. For these reasons we include both limits (i.e., 4%
CO2 ceiling limit in the passenger breathing zone and 3%
CO2 averaged over 15 minutes in the passenger cabin free
space) in this final rule.
    Comment: Several commenters suggested that a CO2 ceiling
limit should rely on exposure time since potential effects of
CO2 vary with both concentration and duration of the
exposure. One commenter stated that if the ceiling limit is exceeded,
it is likely due to collision events.
    Response: EPA agrees the health effects of CO2 are
functions of exposures over time. The commenter appears to
misunderstand what a ceiling limit is. A ceiling limit is a limit that
shall not be exceeded for any period of time, thus it is not consistent
with the concept of a ceiling limit to also include a period of time
during which it cannot be exceeded. As explained previously, we believe
that both a ceiling limit and a STEL are necessary to ensure that risks
posed from CO2 MVAC systems are not greater than risks posed
by other available MVAC systems.
    While EPA agrees with the commenter that collision events are the
most likely cause of a refrigerant leak that could cause CO2
levels to the exceed the ceiling limit established in the use
conditions, there may be other system failures that could cause the
ceiling limit to be exceeded. OEMs should consider risks from all
possible events in designing MVACs for use with CO2.
    Comment: Several commenters suggested considering ceiling limits of
CO2 above 4% (e.g., 6%, 9%) based on studies showing that
visual disturbances occur at concentrations of 6% CO2. They
stated that the SAE CRP report's rationale suggested a 9%
CO2 concentration ceiling limit, based on studies showing
central nervous system (CNS) effects at CO2 exposure
concentrations of 10% (100,000 ppm).
    Response: Studies report that human exposures to 6% CO2
for periods as short as 2 minutes can lead to hearing and visual
disturbances, and that exposures to 7.5% for 5 minutes lead to
significant reasoning and performance decrements (Gellhorn, 1936;
Sayers, 1987 as cited in EPA-HQ-OAR-2004-0488-0041). To provide a
margin of safety, EPA considers it necessary to require a ceiling limit
of 4% CO2 in the passenger breathing zone as indicated in
the NODA and suggested by some commenters, to avoid driver performance
decrement and other adverse health effects on passengers.
    Comment: Several commenters said that the ceiling limit should rely
on NIOSH's Immediately Dangerous to Life and Health (IDLH) value of 4%
CO2 based on a 30-minute exposure.
    Response: EPA disagrees with the commenters to the extent they are
suggesting that the 4% limit be based on a 30-minute exposure. The
NIOSH IDLH value is a worker's exposure limit based on the effects that
might occur as a consequence of a 30-minute exposure (NIOSH 2005; EPA-
HQ-OAR-2004-0488-0041). The OSHA regulation (1910.134(b)) defines the
term as ``an atmosphere that poses an immediate threat to life, would
cause irreversible adverse health effects, or would impair an
individual's ability to escape from a dangerous atmosphere.'' We
believe NIOSH's IDLH is inappropriate as a ceiling limit for the use of
CO2 as a refrigerant in MVACs because, as indicated above, a
ceiling limit is a limit that shall not be exceeded for any period of
time. Also, a 4% limit over 30-minutes would not protect drivers and
passengers from the effects of CO2 exposure at
concentrations equal or higher than 4%. CO2 is an asphyxiant
that obstructs the oxygen flow into the body and we believe that 30-
minute duration, in particular, where the person affected by such a
concentration may be operating a vehicle and thus posing risk to
others, creates a significant risk. Risk Mitigation Strategies
    Comment: The U.S. Army noted a CFD parameter error in their 2005
risk analysis which used an incorrect refrigerant leak angle in their
2005 risk analysis (EPA-HQ-OAR-2004-0488-0017). The U.S. Army corrected
this error for purposes of their 2006 risk analysis by using a
perpendicular leak angle to the rupture cross-sectional area (EPA-HQ-
OAR-2004-0488-0025.1). The 2006 analysis finds that an unmitigated
discharge of CO2, in full recirculation mode, results in
CO2 concentration above 3% for more than 60 minutes. The
U.S. Army also indicated that a 3-second, rather than a 10-second squib
valve, as originally determined, would be needed to ensure that
CO2 concentrations remain below

the 3% on a 15-minute average inside the passenger compartment.
    Response: EPA notes that the U.S. Army is commenting on its own
risk assessment performed in collaboration with EPA and several
stakeholders, and referenced in the NPRM (71 FR 55140). We also note
that the 2005 U.S. Army risk analysis referred in the NRPM (71 FR
55140) contained technical errors (EPA-HQ-OAR-2004-0488-0017). This
final rule relies on the results of the revised (2006) U.S. Army risk
analysis submitted during the public comment period.
    Based on the U.S. Army revised assessment, we understand that, in
order for a squib valve to be an effective mitigation device, the
activation time of such device should be 3 seconds rather than the 10
seconds indicated in the original risk assessment. Since we are not
specifying in this final rule what mitigation strategies must be used,
we believe the 2006 revised risk analysis does not affect the use
conditions addressed in this final rule, but may affect the potential
risk mitigation strategies OEMs might apply for use with CO2
refrigerant.
    Comment: One commenter stated that secondary loop technology is not
a viable risk mitigation strategy for CO2 because of reduced
system performance and reduced fuel efficiency.
    Response: This final rule does not specify design options. EPA does
not intend to limit engineering innovation by requiring any specific
risk mitigation strategy; however, EPA notes that secondary loop
technology could potentially reduce the risks of exceeding the ceiling
limit of CO2 in the passenger compartment because the
refrigerant charge stays separate from the passenger compartment. OEMs
may choose to investigate secondary loops as a risk mitigation
strategy, and would have to weigh the pros and cons, including any
potential effect on fuel efficiency. However, even if secondary loop
technology were not an attractive option, other feasible mitigation
technologies could be applied to meet the use conditions of this final
rule, such as a squib valve with a 3-second response time.
    Comment: One commenter indicated that squib valves with activation
time of less than 10 seconds (e.g., few milliseconds) are available and
such devices have been tested. Another commenter stated that a 10-
second squib valve is not technically feasible given CO2
sensor performance. Additionally, the commenter stated that during
sharp increases in CO2 concentration in the passenger
compartment, a short activation time for a squib-valve would increase
the possibility of purging the refrigerant from the air conditioning
system to outside the vehicle when no leak in fact exists.
    Response: EPA agrees with the first commenter regarding the
availability of squib valves and disagrees with the second commenter's
statement regarding feasibility of a squib valve. The 2006 U.S. Army
risk analysis indicated that a squib valve is one effective strategy
and viable engineering option to reduce the amount of charge that could
potentially leak into the passenger compartment (EPA-HQ-OAR-2004-0488-
0025.2). EPA notes that in the proposal, we intended for the squib
valve activation time to include: 1) the time the sensor takes to
detect a significant leak that would cause CO2 refrigerant
to enter into the passenger compartment, and 2) the time it takes for
the squib valve to open (71 FR 55140; September 21, 2006). The 2006
U.S. Army risk assessment evaluated different activation times (i.e.,
30, 10 and 3 seconds) of squib valve during modeled scenarios of
CO2 refrigerant leak. The results showed higher
effectiveness of the valve preventing high refrigerant concentration
reaching the passenger compartment during the shorter activation time.
    EPA believes that sharp increases in CO2 concentration
in the passenger compartment will likely occur only when a significant
amount of CO2 refrigerant leaks into the passenger
compartment. Risk assessments showed that CO2 buildup due to
passenger respiration occurs slowly (e.g., 60 minutes) to levels up to
2.4% in a fully-occupied 100 cubic feet sealed passenger compartment of
a vehicle with no introduction of outside air (EPA-HQ-OAR-2004-0488-
0025.2, -0041). EPA notes that a passenger compartment in a vehicle is
not confined space and infiltration/exfiltration rates of air changes
within the passenger compartment and outside air are at least 0.3 air
changes per hour (NREL, 2003 as cited in EPA-HQ-OAR-2004-0488-0025.2).
Therefore, we do not agree that refrigerant purging from the air
conditioning system to outside the vehicle will occur when no leak in
fact exists.
    Comment: A commenter stated that odorants that alert drivers to a
leak should be another option for compliance with the rule.
    Response: EPA did not propose the use of odorants, and this final
action neither requires nor prohibits the use of odorants in new
CO2 MVAC systems. Odorized CO2 may be an
effective means to alert the driver and passengers to a refrigerant
leak into the passenger compartment. However, EPA does not believe
odorants used alone provide sufficient risk mitigation as it may take
vehicle occupants a period of time to recognize what the odor
signifies. Documentation has not been provided to show how long and how
much odorized CO2 drivers must be exposed to before they
recognize that the smell indicates a health and safety risk.
    Comment: One commenter suggested that EPA consider use of sensors
to allow continuous monitoring of refrigerant concentration inside the
passenger cabin as a mitigation strategy. Another commenter mentioned
that an alarm system or other technical solutions should allow for air
renewal and lowering concentration levels below the limits indicated in
the use conditions within a reasonable time period
    Response: As noted previously, EPA is not specifying the risk
mitigation strategies that must be used to ensure CO2 levels
do not exceed the levels established in the use conditions. We do not
believe that a sensor alone would be sufficient to provide effective
protection to the passengers and to ensure that concentrations inside
the passenger compartment and passenger breathing zone do not exceed
the established CO2 concentration limits of this final rule.
In response to the commenter stating that an alarm system or other
technical solutions should allow for air renewal, EPA believes the use
of such tool might be effective but that such strategy would need to
rely on an automatic supply of air, rather than a driver's response, to
ensure CO2 concentrations do not exceed the exposure limits
established in the use conditions. Thus, an additional mitigation
device would need to be used in addition to any alarm system.
    Comment: One commenter said that evaporator isolation valves are
not realistic as mitigation devices because of cost. The commenter
stated that close-coupled and hermetically sealed systems are
technically feasible and noted that an automatic increase in air
exchange is a possible strategy that is technically feasible. Another
commenter suggested that switching the MVAC blower to operate on
outside air mode on high, rapidly after CO2 refrigerant is
released, could reduce the overall refrigerant concentration in the
compartment to a peak lower than 4%.
    Response: EPA believes the mitigation strategies mentioned by the
commenters may all be technically feasible means to meet concentration
levels specified in the use conditions. We note that in the proposed
rule we suggested using

evaporator isolation valves, close coupled or hermetically closed
systems that would reduce refrigerant charge size, and increasing air
exchange (with outside air) in the passenger compartment upon detection
of leaks as some of several potential risk mitigation strategies (71 FR
55140; September 21, 2006). In this final rule we are not requiring a
specific mitigation strategy or engineering device. We are allowing
OEMs to choose a mitigation strategy that is consistent with the use
conditions and that they will employ to protect the driver and
passengers in a vehicle from CO2 exposure above the limits
specified in this rule.
    Comment: One commenter stated that a vehicle crash could be so
severe that the MVAC system evaporator could be damaged and possibly
reduce a risk mitigation system's effectiveness. The commenter proposed
the inclusion of an evaporator crush resistance standard in this
action.
    Response: EPA agrees that a vehicle crash could reduce the
effectiveness of the risk mitigation strategy. However we believe that
in such a case, the damage to the car would be so severe as to result
in an inflow of ambient air that would negate the risks associated with
potentially elevated CO2 concentrations. A crush-resistant
evaporator could be selected as a possible mitigation strategy but, as
stated previously, in this final rule we do not specify which
engineering device or strategies must be incorporated into the MVAC
system and leave this choice to the OEMs.

C. Industry Standards

    Comment: Several commenters indicated that SAE is developing
standards for safety and servicing of CO2 MVAC systems and
that it is customary for OEMs to follow those standards. Other
commenter claimed that every OEM is responsible for its own safety
concept and has to show compliance with already existing and future
safety standards.
    Response: EPA notes and agrees with the important role industry
standards play particularly for the MVAC sector. In addition, we note
that the regulatory text references the relevant SAE technical
standards to promote consistency with established industry practices.
Specifically, use conditions in this final rule reference SAE J639
(2011 version). Other standards such as SAE J1739, which addresses
design, safety, and recordkeeping requirements, are recommended to help
ensure that the use conditions are met.
    We disagree with the comment stating that every OEM is responsible
for its own safety concept because we believe that in addition to
customary business standards and industry practices outside the scope
of this rule, OEMs will comply with all the use conditions specified in
this rule.
    Comment: Commenters noted that SAE is developing SAE J2772
standard, ``Measurement of Passenger Compartment Refrigerant
Concentrations Under System Refrigerant Leakage Conditions'' (EPA-HQ-
OAR-2004-0448-0054) and SAE J2773 standard, ``Standard for Safety and
Risk Analysis for Use in Mobile Air Conditioning Systems'' (EPA-HQ-OAR-
2004-0448-00553), formerly known as Refrigerant Guidelines for Safety
and Risk Analysis for Use in Mobile Air Conditioning Systems.
    Response: We note that standards J2772 and J2773 were recently
published and are readily available. In the comments column of our
listing decision, we recommend the use of J2772 and J2773 standards as
well as other available standards such as SAE J1052, Motor Vehicle
Driver and Passenger Head Position (EPA-HQ-OAR-2004-0448-0055).

D. Servicing

    Comment: One commenter indicated CAA Section 609-certified,
independent MVAC service technicians should be consulted before the
rule is issued.
    Response: EPA took comments on a range of topics during the 60-day
public comment period. In addition, EPA contacted the National
Institute for Automotive Service Excellence (ASE), which represents a
significant number of MVAC service technicians. A summary is in the
docket for this final rule. ASE stated they did not see any servicing
concerns in the proposal that would impact the service technicians they
represent, but would be interested in any follow-on rulemaking that
will address MVAC servicing for consideration under CAA Section 609 and
codified at 40 CFR part 82 subpart B (EPA-HQ-OAR-2004-0488-0031).
    Comment: One commenter said risks associated with MVAC service
should be considered.
    Response: EPA agrees with the commenter and notes that risk
associated with service were evaluated in the published risk analyses
(EPA-HQ-OAR-2004-0488-0017, -0025.2, -0041, -0051) and discussed in the
preamble to the proposed rulemaking (71 FR 55144 September 21, 2006).
Additional details regarding our evaluation of risk associated with
MVAC service can be found in Section VI of this final rule preamble
(Why is EPA listing CO2 acceptable subject to use
conditions?). As explained in more detail in Section VI above, we do
not believe it is necessary to establish any use conditions regarding
servicing because the overall environmental and human health risks
posed by the use of CO2 in new MVAC systems, subject to the
use conditions being adopted in this final rule, is lower than or
comparable to the risks posed by other substitutes found acceptable
subject to use conditions in the same end-use. Comment: One commenter
requested more information on why CO2 systems are not found
acceptable as a substitute in retrofitted systems.
    Response: In the original SNAP rulemaking (59 FR 13854; March 18,
1994), EPA listed CO2 as an acceptable substitute for CFC-12
only for new MVAC systems. We have never received a SNAP submission
requesting consideration of CO2 in retrofitted MVAC systems.
EPA understands that the higher working pressure of CO2
compared to CFC-12 and other SNAP-acceptable refrigerants could raise
significant issues with retrofitting such systems to CO2.
Because we have not received a request to use CO2 in
retrofitted systems, which would include the technical and other
analyses necessary to determine whether such use would present more
risk than other available substitutes, this final rule only applies to
the use of CO2 as a refrigerant in new MVAC systems,
consistent with the NPRM (71 FR 55140; September 21, 2006). When and if
the Agency receives a submission for retrofitting to CO2, we
will consider CO2 for use as a refrigerant to retrofit
existing MVAC systems.

IX. 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 a ``significant regulatory action.'' It raises novel
legal or policy issues arising out of legal mandates, the President's
priorities, or the principles set forth in the Executive Order.
Accordingly, EPA submitted this action to the Office of Management and
Budget (OMB) for review under Executive Orders 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 any new information collection burden
under the Paperwork Reduction Act (44 U.S.C.

3501 et seq). This action is an Agency determination. It contains no
new requirements for reporting. The only new recordkeeping requirement
involves customary business practice. This rule requires minimal
recordkeeping of studies done for three years to ensure that MVAC
systems using CO2 meet the requirements set forth in this
rule. Because it is customary business practice that OEMs conduct and
keep on file records of the tests they perform, consistent with a
widely recognized industry standard, SAE J1739 (Potential Failure Mode
and Effect Analysis in Design [Design FMEA], Potential Failure Mode and
Effect Analysis in Manufacturing and Assembly Processes [Process
FMEA]), on any potentially hazardous part or system from the beginning
of production of a vehicle model until three years or more after
production of the model ends, we believe this requirement will not
impose an additional paperwork burden. However, the Office of
Management and Budget (OMB) has previously approved the information
collection requirements contained in the existing regulations in
subpart G of 40 CFR part 82 under the provisions of the Paperwork
Reduction Act, 44 U.S.C. 3501 et seq. and has assigned OMB control
numbers 2060-0226. The OMB control numbers for EPA's regulations are
listed in 40 CFR part 9.

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
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 today's rule on small
entities, small entity is defined as: (1) A small business, as defined
by the Small Business Administration's (SBA) regulations at 13 CFR
121.201;'' (2) a small 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 final rule on small
entities, I certify that this action will not have a significant
economic impact on a substantial number of small entities. This final
rule modifies the current listing of CO2 as an acceptable
alternative refrigerant subject to use conditions necessary for the
safe use of CO2 in MVAC in new motor vehicles. The use
conditions will need to be met by large entities (i.e., OEMs) that
manufacturer motor vehicles if these choose to use CO2 as a
refrigerant in new MVACs. This final rule does not mandate the use of
CO2 as a refrigerant in new MVAC systems, thus will not
impose significant requirements on small entities such as MVAC service
shops. This final rule effectively ensures consistency with current
practices in MVAC service shops regarding the use of unique fittings.
It is not clear that there would be any cost differential between the
unique fittings required for the use of CO2 and those used
with the current automotive refrigerant, HFC-134a, or other fittings
that the industry could adopt instead, for other refrigerants. It is
possible that the fittings required in the revised use condition will
be equally or less expensive than those required for other acceptable
alternative refrigerants because they are a standard shape and size and
can be easily produced in a metal-working shop. Thus, cost impacts of
this final rule on small entities are expected to be small.
    Although this final rule will not have a significant economic
impact on a substantial number of small entities, EPA nonetheless has
tried to reduce the impact of this rule on small entities. EPA has
worked together with SAE International and with groups representing
professional service technicians such as the Mobile Air Conditioning
Society Worldwide, which conducts regular outreach with technicians and
owners of small businesses such as retail refrigerant suppliers and
automobile repair shops.

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. This action does not affect State, local, or tribal
governments. The enforceable requirements of this action related to
integrating risk mitigation devices and documenting the safety of
alternative MVAC systems affect only a small number of OEMs. The impact
of this action on the private sector will be less than $100 million per
year. Thus, 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. This action applies directly to facilities that use these
substances and not to governmental entities.

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 EO 13132 (64 FR 43255, August 10, 1999). This regulation
applies directly to facilities that use these substances and not to
governmental entities. Thus, EO 13132 does not apply to this rule.

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

    This final rule does not have tribal implications, as specified in
EO 13175 (65 FR 67249, November 6, 2000). It does not significantly or
uniquely affect the communities of Indian tribal governments, because
this regulation applies directly to facilities that use these
substances and not to governmental entities. Thus, EO 13175 does not
apply to this rule.

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

    This final rule is not subject to the EO 13045 (62 FR 19885, April
23, 1997) because it is not economically significant as defined in
Executive Order 12866, and because the Agency does not have reason to
believe the environmental health or safety risks addressed by this
action present a disproportionate risk to children. This action's
health and risk assessments are discussed in sections VI and VIII of
the preamble and in documents EPA-HQ-OAR-2004-0488-0025.2, EPA-HQ-OAR-
2004-0488-0041 and EPA-HQ-OAR-2004-0488-0051 in the docket for this
rulemaking.

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

    This rule is not a ``significant energy action'' as defined in
Executive Order 13211 (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 would impact manufacturers
of CO2 MVAC systems for new vehicles.

Preliminary information indicates that these new systems are equally or
more energy efficient than currently available systems in some
climates. Therefore, we conclude that this rule is not likely to have
any adverse effects on energy supply, distribution or use.

I. National Technology Transfer Advancement Act

    Section 12(d) of the National Technology Transfer and Advancement
Act of 1995, Public Law 104-113, Section 12(d) (15 U.S.C. 272 note)
directs EPA to use voluntary consensus standards in 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. NTTAA directs EPA to provide
Congress, through OMB, explanations when the Agency decides not to use
available and applicable voluntary consensus standards.
    This rulemaking involves technical standards. EPA has incorporate
by reference, the 2011 version of SAE standard J639 which is a
voluntary consensus standard. This standard can be obtained from http://www.sae.org/technical/standards/. This standard addresses safety and
reliability issues of CO2 MVAC systems.

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

    Executive Order 12898 (59 FR 7629; February 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.
    EPA has determined that this final rule will not have
disproportionately high and adverse human health or environmental
effects on minority or low-income populations because it increases the
level of environmental protection for all affected populations without
having any disproportionately high and adverse human health or
environmental effects on any population, including any minority or low-
income population. The refrigerant CO2 is a non ozone-
depleting substance with a GWP of 1.0. Based on the toxicological and
atmospheric data described earlier, the use of CO2 subject
to the use conditions specified in this final rule will not have any
disproportionately high and adverse human health or environmental
effects on any population, including any minority or low-income
population. This final rule requires specific use conditions for MVAC
systems, if motor vehicle manufacturers choose to market MVAC systems
using this refrigerant alternative.

K. Congressional Review Act

    The Congressional Review Act, 5 U.S.C. 801 et seq., as added by the
Small Business Regulatory Enforcement Fairness Act of 1996, generally
provides that before a rule may take effect, the agency promulgating
the rule must submit a rule report, which includes a copy of the rule,
to each House of Congress and to the Comptroller General of the United
States. EPA will submit a report containing this rule and other
required information to the U.S. Senate, the U.S. House of
Representatives, and the Comptroller General of the United States prior
to publication of the rule in the Federal Register. A Major rule cannot
take effect until 60 days after it is published in the Federal
Register. This action is not a ``major rule'' as defined by 5 U.S.C.
804(2). This rule will be effective August 6, 2012.

X. References

    The documents below are referenced in the preamble. All documents
are located in the Air Docket at the address listed in section titled
ADDRESSES at the beginning of this document. Unless specified
otherwise, all documents are available in Docket ID No. EPA-HQ-OAR-
2004-0488 at http://www.regulations.gov.

ACGIH, 2005a. TLVs[supreg] and BEIs[supreg] Based on the
Documentation of the Threshold Limit Values for Chemical Substances
and Physical Agents & Biological Exposure Indices. American
Conference of Governmental Industrial Hygienists (ACGIH),
Cincinnati, Ohio.
ACGIH, 2005b. Documentation of the Threshold Limit Values for
Chemical Substances: Carbon Dioxide. American Conference of
Governmental Industrial Hygienists (ACGIH), Cincinnati, Ohio.
Aero Medical Association, 1953. Committee on Aviation Toxicology,
Blakiston, New York. As cited in CDC IDLH documentation for carbon
dioxide. Available online at: http://www.cdc.gov/niosh/idlh/124389.html.
Al-Delaimy W.K., Hay S.M., Gain K.R., Jones D.T., Crane J., 2001.
The effects of carbon dioxide on exercise-induced asthma: an
unlikely explanation for the effects of Buteyko breathing training.
Med J Aust. 15,174(2):64-5.
ANSI/ASHRAE, 2007. ASHRAE Standard 62.1-2007: Ventilation for
Acceptable Indoor Air Quality. American National Standard Institute,
American Society for Heating, Refrigerating, and Air-Conditioning
Engineers (ASHRAE), Atlanta, GA. Available online at: http://www.sae.org/altrefrigerant/presentations/sumantran.pdf.
ASHRAE, 2006. BSR/ASHRAE Addendum to ANSI/ASHRAE Standard 34-2004--
Designation and Safety Classification of Refrigerants, Publication
Draft. American Society for Heating, Refrigerating, and Air-
Conditioning Engineers (ASHRAE), Atlanta, GA.
Atkinson, W., 2002. Consumer Use of A/C Systems. SAE Automotive
Alternate Refrigerant Systems Symposium 2002. Phoenix, Arizona.
Available online at: http://www.sae.org/events/aars/2002/consumeruse.pdf.
Amin, J., B. Dienhart, and J. Wertenbach., 1999. Safety Aspects of
an A/C System with Carbon Dioxide as Refrigerant, SAE Subcommittee
Safety of Refrigerant Systems. Available online at: http://www.sae.org/misc/aaf99/visteon.pdf.
Birgfeld, E., 2003. Risk Analysis for CO2, HFC-152a, and
Hydrocarbon Refrigerants in MACs, presented at The Earth
Technologies Forum, Washington, DC, April 2003.
Beck J.G., P.J. Ohtake, and J.C. Shipherd., 1999. Exaggerated
anxiety is not unique to CO2 in panic disorder: A
comparison of hypercapnic and hypoxic challenges. J Abnorm Psychol
108:473-482.
Blackwell, N., L. Bendixen, E. Birgfield., 2006. Risk Analysis for
Alternative Refrigerant in Motor Vehicle Air Conditioning.
Brown. E.W., 1930. The value of high oxygen in preventing the
physiological effects of noxious concentrations of carbon dioxide
U.S. Naval Med. Bull. 132, 523-553. As cited in Wong 1992.
Bureau of Labor Statistics (BLS), 2003. ``Workplace Injuries and
Illnesses in 2002,'' December 18, 2003.
CATAM., 1953. Aviation Toxicology, An Introduction to the Subject
and a Handbook of Data. Committee on Aviation Toxicology, Aero
Medical Association. The Blakiston Co.: New York, NY. Pp. 6-9, 31-
39, 52-55, 74-79, 110-115. As cited in Wong 1992.
Compressed Cylinder Gas (CGA) Association, 1999. Properties,
Manufacture, Uses, and Special Requirements for Safe Handling.
Carbon Dioxide. Handbook of Compressed Gases, 4th edition.
Arlington, VA Klever Academy. Pages 300-308.
CRP, 2009. Risk Assessment for Alternative Refrigerants HFO-1234yf
and R-744 (CO2) Phase III. Prepared for SAE International
Cooperative Research Program 1234 by T. Lewandowski, Gradient
Corporation. December 17, 2009.
DOT, Federal Aviation Authority, 1996. Allowable carbon dioxide
concentration in transport category airplane cabins;

final rule. Federal Register 61(232):63951-63956. Available online
at: http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgFinalRule.nsf/0/51B4BFD4B3B081968625683A005905BE.
Dripps, R.D., J.H. Comroe, Jr., 1947. The respiratory and
circulatory response of normal man to inhalation of 7.6 and 10.4
percent CO2 with a comparison of the maximal ventilation
produced by severe muscular exercise, inhalation of CO2
and maximal voluntary hyperventilation. Am J Physiol 149:43-51. As
cited in NIOSH, 1976 and NRC, 1996.
ERG Inc., 2009. Review of Health Impacts from Short Term Carbon
Dioxide Inhalation Exposures. 110 Hartwell Ave. Lexington, MA 02421.
February 18, 2009.
Froehling, J., M. Lorenz-Boernert, F. Schroeder, V. Khetarpal, S.
Pitla. (2002) ``Component Development for CO2,''
presented at 2002 SAE Automotive Alternate Refrigerant Systems
Symposium, Scottsdale, Arizona. Available online at: http://www.sae.org/events/aars/2002/froehling.pdf.
Gellhorn, E. (1936). The Effect of O2-Lack, Variations in the Carbon
Dioxide-Content of the Inspired Air, and Hyperpnea on Visual
Intensity Discrimination. American Journal of Physiology. 115: 679-
684.
Hunter D. (1975). The diseases of occupations. 5th ed. London:
Hodder and Stoughton, p. 618 Jetter, J., R. Forte, and F. Delafield.
(2001) ``Refrigerant Concentrations in Motor Vehicle Passenger
Compartments,'' ASHRAE Transactions: Research, No. 4466, pp. 99-107.
Lambertsen, C.J. (1971). Therapeutic Gases: Oxygen, Carbon Dioxide,
and Helium. In Drill's Pharmacology in Medicine, ed. J.R. DiPalma,
1145-1179. New York, NY: McGraw-Hill.
NIOSH, 1976. Criteria for Document for Carbon Dioxide. NIOSH
Publication No. 76-194.
NIOSH, 1990. Pocket Guide to Chemical Hazards. U.S. Department of
Health and Human Services, Centers for Disease Control and
Prevention, National Institutes for Occupational Safety and Health
(NIOSH), Washington, DC. Available online at: http://www.cdc.gov/niosh/npg/.
NIOSH, 1996. Documentation for Immediately Dangerous to Life or
Health Concentrations (IDLHs): Carbon dioxide. U.S. Department of
Health and Human Services, Centers for Disease Control and
Prevention, National Institutes for Occupational Safety and Health
(NIOSH), Washington, DC. Available online at: http://www.cdc.gov/niosh/idlh/124389.html.
NIOSH, 2005. Pocket Guide to Chemical Hazards. U.S. Department of
Health and Human Services, Centers for Disease Control and
Prevention, National Institutes for Occupational Safety and Health
(NIOSH), Washington, DC. Available online at: http://www.cdc.gov/niosh/npg/.
NRC, 1996. Spacecraft Maximum Allowable Concentrations for Selected
Airborne Contaminants: Volume 2. Subcommittee on Spacecraft Maximum
Allowable Concentrations, Committee on Toxicology, Board on
Environmental Studies and Toxicology, Commission on Life Sciences,
National Research Council (NRC). Washington, DC: National Academies
Press. Available online at: http://archive.org/details/nasa_techdoc_19970023991.
NRC, 2007. Emergency and Continuous Exposure Guidance Levels for
Selected Submarine Contaminants. Subcommittee on Emergency and
Continuous Exposure Guidance Levels for Selected Submarine
Contaminants, Committee on Toxicology, Board on Environmental
Studies and Toxicology, National Research Council (NRC). Washington,
DC: National Academies Press. Available online at: http://www.nap.edu/catalog.php?record_id=11170#toc.
OSHA, 1989. Carbon Dioxide, Industrial Exposure and Control
Technologies for OSHA Regulated Hazardous Substances, Volume I of
II, Substance A-I. Occupational Safety and Health Administration.
Washington, DC: U.S. Department of Labor. March 1989.
OSHA, 1993. Final Rule on Air Contaminants: FR 58:35338-35351, June
30, 1993. U.S. Department of Labor, Occupational Safety and Health
Administration (OSHA), Washington, DC. Available online at: http://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=FEDERAL_REGISTER&p_id=13306.
OSHA, 1996. Hazard Information Bulletin. Potential Carbon Dioxide
(CO2) Asphyxiation Hazard When Filling Stationary Low
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STATIC&p--id=35791&p--search--type=CLOBTEXTPOLICY&p--search--
str=carbon+dioxide&p--text--version=FALSE#ctx1.
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Air Contaminants--1910.1000. U.S. Department of Labor, Occupational
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online at: http://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=STANDARDS&p_id=9992.
Patterson, J.L., H. Heyman, L.L. Battery, R.W. Ferguson., 1955.
Threshold of response of the cerebral vessels of man to increases in
blood carbon dioxide. Journal of Clinical Investigations. 34:1857-
1864.
Pine, D.S. et al., 2005. Response to 5% carbon dioxide in children
and adolescents: relationship to panic disorder in parents and
anxiety disorders in subjects. Arch Gen Psychiatry 62:73-80.
Available online at: http://archpsyc.ama-assn.org/cgi/content/full/62/1/73.
Rebinger, C., 2005. Safety Concept Proposal for R744 A/C Systems in
Passenger Cars--Update 2005. VDA Alternate Refrigerant Winter
Meeting 2005. Saalfelden, Austria.
RISA Sicherheitsanalysen., 2002. Safety-Study for a Prototypical
Mobile R744 A/C System. VDA Alternate Refrigerant Winter Meeting
2002. Saalfelden, Austria.
Schaefer K.E., 1951. Studies of carbon dioxide toxicity. New London,
CT: Navy Department, Bureau of Medicine and Surgery, Medical
Research Laboratory, U.S. Naval Submarine Base, Vol. 10, Report
No.181, pp. 156-189. As cited in NIOSH documentation for carbon
dioxide. Last accessed January 23, 2009: http://www.cdc.gov/niosh/idlh/124389.html.
Sayers, J.A., R.E.A. Smith, R.L Holland, W.R. Keatinge. 1987.
Effects of Carbon Dioxide on Mental Performance. Journal of Applied
Physiology. 63(1):25-30.
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respiration of an increase in the carbon dioxide content of blood in
man. American Journal of Physiology. 63:155-175.
Schulte, J.H., 1964. Sealed environments in relation to health and
disease. Archives of Environmental Health. 8: 438-452.
SAE International, 2002. Surface Vehicle Standard J1052. Motor
Vehicle Driver and Passenger Head Position.
SAE International, 2005. Surface Vehicle Standard J2683. Refrigerant
Purity and Containment Requirements for Carbon Dioxide
(CO2 R-744) Used in Mobile Air-Conditioning Systems.
SAE International, 2009. Surface Vehicle Standard J1739. Potential
Failure Mode and Effect Analysis in Design (Design FMEA), Potential
Failure Mode and Effect Analysis in Manufacturing and Assembly
Processes (Process FMEA).
SAE International, 2011. Surface Vehicle Standard J639. Safety
Standards for Motor Vehicle Refrigerant Vapor Compression Systems.
SAE International, 2011. Surface Vehicle Standard J2772. Measurement
of Passenger Compartment Refrigerant Concentrations Under System
Refrigerant Leakage Conditions.
SAE International, 2011. Surface Vehicle Standard J2773. Standard
for Refrigerant Risk Analysis for Mobile Air Conditioning Systems.
Sumantran, V., B. Khalighi, K. Saka, and S. Fischer., 1999. An
Assessment of Alternative Refrigerants for Automotive Applications
based on Environmental Impact. General Motors R&D Center and Oak
Ridge National Laboratory. Available online at: http://www.sae.org/altrefrigerant/presentations/sumantran.pdf.
U.S. EPA., 1994. SNAP Technical Background Document: Risk Screen on
the Use of Substitutes for Class I Ozone-Depleting Substances:
Refrigeration and Air Conditioning. Stratospheric Protection
Division. March 1994.
U.S. EPA., 2005. Risk Analysis for Alternative Refrigerant in Motor
Vehicle Air Conditioning.
U.S. EPA, 2010. Email from Yaidi Cancel, EPA to William Hill and
Ward Atkinson, SAE Interior Climate Control Committee re: Minimum
recordkeeping on SAE J1739. August 16, 2010.

White, C.S.; Humm, J.H.; Armstrong, E.D.; Lundgren, N.P.V., 1952.
Human tolerance to acute exposures to carbon dioxide. Report No. 1
Six percent carbon dioxide in air and in oxygen. Aviation Med. Oct.
issue. pp 439-455. As cited in Wong 1992.
Wong, K.L., 1992. Carbon Dioxide. Internal Report, Johnson Space
Center in the Group. National Aeronautics and Space Administration,
Huston, TX. 1987.
Yang, Y., S. Changnian, and M. Sun., 1997. The effect of moderately
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motion. Aviat Space Environ Med 68(3):187-191.

List of Subjects in 40 CFR Part 82

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

    Dated: May 23, 2012.
Lisa P. Jackson,
Administrator.
    For the reasons set out in the preamble, 40 CFR Part 82 is amended
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 B to Subpart G of Part 82, add an entry to the end of
the table for ``Refrigerants-Acceptable Subject to Use Conditions,''
and revise footnotes 1, 2, and 3 to read as follows:

Appendix B to Subpart G of Part 82--Substitutes Subject To Use
Restrictions and Unacceptable Substitutes

                                Refrigerants-Acceptable Subject to Use Conditions
----------------------------------------------------------------------------------------------------------------
          Application              Substitute         Decision            Conditions              Comments
----------------------------------------------------------------------------------------------------------------

                                                  * * * * * * *
CFC-12 Motor Vehicle Air        Carbon dioxide    Acceptable        Engineering            Additional training
 Conditioning (New equipment     (CO2) as a        subject to use    strategies and/or      for service
 only).                          substitute for    conditions.       mitigation devices     technicians is
                                 CFC-12.                             shall be               recommended.
                                                                     incorporated such
                                                                     that in the event of
                                                                     refrigerant leaks,
                                                                     the resulting CO2
                                                                     concentrations do
                                                                     not exceed:
                                                                    The short term         In designing risk
                                                                     exposure level         mitigation
                                                                     (STEL) of 3% or        strategies and/or
                                                                     30,000 ppm averaged    devices,
                                                                     over 15 minutes in     manufacturers should
                                                                     the passenger free     factor in background
                                                                     space \1\; and;        CO2 concentrations
                                                                    The ceiling limit of    in the passenger
                                                                     4% or 40,000 ppm in    cabin potentially
                                                                     the passenger          contributed from
                                                                     breathing zone.\2\.    normal respiration
                                                                                by the maximum
                                                                                number of vehicle
                                                                                occupants.
                                                                    Vehicle manufacturers  Use of the standards
                                                                     must keep records of   SAE J1052, SAE
                                                                     the tests performed    J2772, and SAE J2773
                                                                     for a minimum period   is recommended as
                                                                     of three years         additional
                                                                     demonstrating that     reference.
                                                                     CO2 refrigerant
                                                                     levels do not exceed
                                                                     the STEL of 3%
                                                                     averaged over 15
                                                                     minutes in the
                                                                     passenger free
                                                                     space, and the
                                                                     ceiling limit of 4%
                                                                     in the breathing
                                                                     zone.
                                                                    The use of CO2 in      Manufacturers should
                                                                     MVAC systems must      conduct and keep on
                                                                     adhere to the          file Potential
                                                                     standard conditions    Failure Mode and
                                                                     identified in SAE      Effects Analysis in
                                                                     Standard J639 (2011    Design [Design
                                                                     version) including:    FMEA], Potential
                                                                    Installation of a       Failure Mode and
                                                                     high pressure system   Effect Analysis in
                                                                     warning label;.        Manufacturing and
                                                                    Installation of a       Assembly Process
                                                                     compressor cut-off     [Process FMEA] on
                                                                     switch; and.           the MVAC as stated
                                                                    Use of unique           in SAE J1739.
                                                                     fittings with:.
                                                                    Outside diameter of
                                                                     16.6 +0/-0.2 mm
                                                                     (0.6535 +0/-0.0078
                                                                     inches) for the MVAC
                                                                     low-side;.
                                                                    Outside diameter of
                                                                     18.1 +0/-0.2 mm
                                                                     (0.7126 +0/-0.0078
                                                                     inches) for the MVAC
                                                                     high-side; and.
                                                                    Outside diameter of
                                                                     20.955 +0/-0.127 mm
                                                                     (0.825 +0/-0.005
                                                                     inches) and right-
                                                                     hand thread
                                                                     direction for CO2
                                                                     refrigerant service
                                                                     containers.\3\.
----------------------------------------------------------------------------------------------------------------
\1\ Free space is defined as the space inside the passenger compartment excluding the space enclosed by the
  ducting in the HVAC module.
\2\ Area inside the passenger compartment where the driver's and passengers' heads are located during a normal
  sitting position. Refer to SAE J1052 for information on determining passenger head position.
\3\ The refrigerant service containers fitting requirement applies only to refrigerant service containers used
  during servicing of the MVAC, in accordance with the provisions established for MVAC servicing under 40 CFR
  part 82, subpart B.

* * * * *
[FR Doc. 2012-13189 Filed 6-5-12; 8:45 am]
BILLING CODE 6560-50-P