risk to DIYers (EPA-HQ-OAR-2008-0664-0036). As stated previously in
this action, this issue is further addressed through the Agency's
authority under TSCA.
    Comment: In response to EPA's risk assessment (EPA-HQ-OAR-2008-
0664-0036), two commenters disagreed with the use of a 2-week study for
evaluating 30 minute exposures and stated that acute toxicity (4-hour
test) or cardiac sensitization test results would be more appropriate
for acute exposure evaluations.
    Response: Commenters have suggested that EPA use data from the 4-
hour acute toxicity study or from the cardiac sensitization study as a
starting point (``point of departure'') for assessing risks of short-
term (acute) exposure. However, cardiac sensitization studies are for
very short durations--on the order of 10 minutes--and they only address
cardiac sensitization. HFO-1234yf does not induce cardiac
sensitization. EPA selected the point of departure for acute effects
from a multiple-exposure 2-week (subacute) rat inhalation study on HFO-
1234yf, reasoning that if no effects were seen in the duration of the
study (6 hours per day, 5 days per week for 2 weeks), that no effects
would be seen from a single exposure at a similar exposure level,
either. Further, the subacute exposure rat study included more thorough
pathology examinations than those included in a cardiac sensitization
study.
    The acute 4-hour exposure study in rats showed some lung effects at
approximately 200,000 ppm, the lowest exposure level in the study. Thus
EPA considers 200,000 ppm to be a LOAEL (Low-Observed-Adverse-Effect
Level). If a LOAEL were used in the risk assessment instead of a NOAEL,
EPA would use an uncertainty factor to estimate a NOAEL, which would
result in a lower POD than what was used. For example, if EPA had
started with the LOAEL of 200,000 ppm, it would have required an
additional MOE of 10 to estimate a NOAEL from a LOAEL, for a total MOE
of 300 instead of 30. This would have resulted in a more conservative
risk assessment than using the NOAEL from the 14-day subacute study. In
the 4-hour acute toxicity study, some of the animals had grey,
discolored lungs at all exposure levels in the study, and we considered
this an adverse effect. Thus, EPA could only determine a lowest
observed adverse effect level (LOAEL) from the 4-hour acute study and
could not determine a no observed adverse effect level (NOAEL). It is
longstanding Agency policy to use the NOAEL where available instead of
a LOAEL, because of greater assurance of a safe exposure level. EPA
instead used the NOAEL for the next shortest study, the subacute 14-day
study, as the endpoint of concern for short term exposure because the
LOAEL from the acute 4-hour study is an endpoint showing effects that
may not result in safe exposure levels for humans. If we had used the
value from the 4-hour acute toxicity study, we would have had to
consider additional uncertainty that would have resulted in a more
conservative, more restrictive risk assessment than using the NOAEL
from the 14-day subacute study.
    Further, EPA has uncertainties about using the available single
exposure studies on HFO-1234yf to determine the MOEs for different
exposure scenarios. As a result of concerns with these studies, EPA
calculated single exposure MOEs from the NOAEL in the 2-week inhalation
toxicity study of HFO-1234yf in rats. There are some uncertainties in
the single exposure (acute) assessments because of the observation of
lethality in rabbit dams after multiple exposures to HFO-1234yf in a
developmental study. For these reasons, EPA recommended an acute
inhalation toxicity study on rabbits in the proposed SNUR to address

the question of whether pregnant rabbits would die from a single
exposure (April 2, 2010; 75 FR 16706).
    Comment: A commenter asserted that EPA's methodology to estimate
the exposure levels associated with the DIY use, using the SAE CRP
(2008) Phase II Report, greatly exaggerates the exposure that could be
experienced in actual use conditions. Another commenter calculated
exposure to a DIYer assuming that the refrigerant fills a garage and
concluded that exposure would be less than the manufacturer's
recommended exposure limit of 1000 ppm. The first commenter stated that
the 30 minute time-weighted average (TWA) value used by the EPA is
unrealistic as are the exposure estimates presented in Scenarios 1 and
2 of the supporting document EPA-HQ-OAR-2008-0664-0036. The specific
exposure parameters that the commenters questioned were assumptions
regarding:
     Garage volume;
     Time the user spent under the hood during recharging
operations;
     The size of the space where any leaking gas would
disperse;
     The air exchange rate in a service area that should be
well-ventilated when the engine is running;
     Use of the refrigerant in a closed garage with no
ventilation; and,
     The amount of refrigerant used during recharge operations.
    During the comment period for the proposed SNUR, the PMN and SNAP
submitter conducted a simulated vehicle service leak testing, using
HFC-134a as a surrogate, indicating that exposures from use of a 12-oz
can during consumer DIY use are below the Agency's level of concern for
HFO-1234yf (Honeywell, 2010a).
    Response: Concerning exposure estimates for DIYers, the exposure
values in the EPA risk assessment (EPA-HQ-OAR-2008-0664-0036) are
bounding estimates of the maximum possible theoretical concentrations.
The EPA assessment used the industry-modeled DIY scenarios and
assumptions in a 2008 report by Gradient Corporation for the SAE CRP
(CRP, 2008) as a starting point for creating the bounding estimates. To
do so, EPA assumed that the entire leakage mass of each industry-
modeled scenario was released to its corresponding volume with no air
exchange. These assumptions are conservative and protective, as
intended.
    We considered the calculations provided by one commenter that
assumed that the refrigerant fills a garage. However, this analysis
assumes a longer-term, steady-state concentration after the refrigerant
has diffused throughout the garage and uses a long-term, 8-hour time-
weighted average exposure recommendation for comparison. EPA's concerns
about DIY consumer exposure focuses on short-term acute exposures,
including peak exposures over a few minutes near the consumer's mouth
and nose because typically a DIY consumer will only need a short period
of time to recharge a single MVAC system (Clodic et al., 2008). Thus,
the commenter's calculations do not address EPA's concerns.
    After reviewing the consumer DIY use exposure study from the SNAP/
PMN submitter, EPA responded with a list of clarifying questions (U.S.
EPA, 2010c), to which the submitter subsequently responded (Honeywell,
2010b). Although the submitter's responses were helpful, EPA still has
concerns about potential exposures to consumers during DIY use and the
inherent toxicity of HFO-1234yf. However, since this acceptability
determination is limited to use with fittings for large containers,
which DIYers would not purchase, our concerns about potential health
risk to DIY users need not be addressed in this action. We would plan
to evaluate this issue further before taking a final action on a SNAP
submission for unique fittings for small containers. We further note
that the Agency would analyze this issue in the context of any SNUN
filed pursuant to the recently issued SNUR (75 FR 65987). Although we
do not reach any conclusion in this final rule regarding safe use by
DIYers, we make the following observations about the submitted study.
With regards to exposure, the peak concentration values from the
submitted study are as high as 3% by volume, equivalent to 30,000 ppm.
These peaks appeared to occur in the first one or two minutes of each
emission. Accordingly, EPA would need exposure data presented and
averaged out over shorter Time Weighted Averages (TWAs) than the 30
minutes currently in the study, because it would appear that a number
of these early exposure peaks could result in TWA values that would
result in MOEs less than the acceptable Agency level of 30 described
above in this section. This is important because the data on HFO-1234yf
are insufficient to differentiate whether the toxicity is due to blood
level alone from an acute exposure, is due to accumulated exposure over
time (``area under the curve''), or is due to some combination of both.
Since blood equilibrium levels are reached within minutes, a high level
of exposure in a short duration could result in blood levels exceeding
a threshold if the mode of action of the toxicity of HFO-1234yf is due
to blood levels of the chemical. EPA expects that exposure data with
additional TWAs of 3, 5, and 10 minutes would help to resolve these
issues of consumer exposure.
    Comment: One commenter stated that HFOs could harm the human
nervous system. The commenter cited a diagram of breakdown products in
a slide presentation given by the Montreal Protocol Scientific
Assessment Panel in July 2009 and suggested that the toxic impact of
aldehydes formed as breakdown products would be higher than that of
carbonic acids.
    Response: EPA agrees that the breakdown products from the
decomposition of HFO-1234yf will include aldehydes, but we disagree
that this is a cause for concern. The aldehydes that would be produced
as atmospheric breakdown products of HFO-1234yf are formaldehyde and
acetaldehyde (ICF, 2010d). Their health effects include respiratory
effects; irritation of the eyes, nose, and throat; and corrosion of the
gastrointestinal tract. EPA also considers formaldehyde and
acetaldehyde to be probable human carcinogens (U.S. EPA, 2000; ICF,
2010d). The decomposition products of HFO-1234yf are not noted for
causing neurotoxic effects, and toxicity tests for HFO-1234yf did not
identify this as an effect.
    As part of analysis of the atmospheric breakdown products of HFO-
1234yf, we found that worst-case concentrations of formaldehyde would
reach 6 to 8 parts per trillion (ppt) on a monthly basis or an average
of 3 ppt on an annual average basis, compared to a health-based limit
of 8000 ppt \23\--i.e., a level that is roughly 1000 to 2600 times
lower than the health-based limit (ICF, 2010d). Acetaldehyde levels
would be even lower, with worst-case concentrations of 1.2 ppt and
annual average concentrations of 0.23 ppt, compared to a health-based
limit of 5000 ppt \24\ (ICF, 2010d). Thus, aldehydes that would be
decomposition products of HFO-1234yf in the atmosphere would not
contribute significantly to adverse human health effects (ICF, 2010d).
---------------------------------------------------------------------------

    \23\ The Agency for Toxic Substances and Disease Registry
(ATSDR) has established a chronic inhalation minimal risk level
(MRL) of 0.008 ppm (8,000 ppt) for formaldehyde (ICF, 2010d). MRLs
are available at http://www.atsdr.cdc.gov/mrls/mrls_list.html.
    \24\ EPA has established a Reference Concentration (RfC) of
0.005 ppm (5,000 ppt or 0.009 mg/m\3\) for acetaldehyde (ICF,
2010d). A summary of EPA's documentation for its risk assessment and
RfC derivation for acetaldehyde is available online at http://www.epa.gov/ncea/iris/subst/0290.htm.
---------------------------------------------------------------------------

    Aldehydes, including formaldehyde and acetaldehyde, are already
present in

the atmosphere in significant amounts from natural sources such as
plants, from direct emissions, from combustion products, or from
breakdown of other compounds such as hydrocarbons (NRC, 1981; Rhasa and
Zellner, 1987). The current background level of formaldehyde in the
atmosphere ranges from 80 ppt in pristine areas to approximately 3300
ppt in New York, NY--one to three orders of magnitude more than the
worst-case generation of formaldehyde from HFO-1234yf (ICF, 2010d). The
maximum incremental acetaldehyde concentration calculated due to use of
HFO-1234yf was approximately three orders of magnitude less than the
average concentration of acetaldehyde in areas with pristine air
quality (ICF, 2010d). Thus, the additional aldehydes created during
decomposition of HFO-1234yf in the atmosphere are not likely to have a
significant impact on human health.
    Comment: Some commenters stated that additional research and review
of the available information regarding toxicity of HFO-1234yf needs to
be conducted.
    Response: EPA has an obligation to act on submissions in a timely
manner under the Act (Sec.  612(d)). Our risk assessments to date have
found no significant risk for car passengers or drivers, professional
servicing personnel, or workers disposing of or recycling vehicles
containing HFO-1234yf. We believe these assessments are sufficient to
support this action. We note that these assessments rely on somewhat
conservative assumptions.
    We note that we expect there will be no toxicity risks to DIYers
because EPA must receive and take regulatory action to allow unique
fittings for use with small cans of refrigerant before DIYers could be
exposed, as per appendix D to subpart G of 40 CFR part 82. Further,
because HFO-1234yf is not expected to be introduced into any new cars
until late 2011 or later, we expect to have further information and to
take further action before DIYers could be exposed. In addition, the
final SNUR would not allow distribution in commerce of products
intended for use by a consumer for the purposes of servicing,
maintenance and disposal involving HFO-1234yf until at least 90 days
after submission of a SNUN.
    We recognize that more studies will be performed on HFO-1234yf,
further addressing risk. EPA's New Chemicals Program has recommended
additional testing of acute exposure in rabbits, including pregnant
rabbits (April 2, 2010; 75 FR 16706). In addition, the manufacturer is
voluntarily conducting a multi-generation reproductive study. If these
or other future studies call into question the basis for our decision
today, section 612 allows citizens to petition EPA to change or modify
a listing decision or EPA could determine on its own to reassess this
decision.
    Comment: In late comments, a commenter stated that EPA appears to
be relying on a SNUR to reduce risks to human health from exposure to
HFO-1234yf. This commenter stated that EPA must re-open the comment
period on the proposed SNAP rule so that commenters may reassess the
extent to which the final restrictions of the SNUR will be effective at
limiting adverse human health effects. The same commenter noted that
information on new price levels and availability is needed to assess
the effectiveness of the SNUR.
    Response: EPA's final SNUR addresses potential risks to human
health from exposure to HFO-1234yf. However, as discussed above in
section V of the preamble, ``Why is EPA listing HFO-1234yf as
acceptable subject to use conditions?'', this final SNAP rule does not
allow for the use of HFO-1234yf with small cans or containers (i.e.,
container sizes that would be purchased by DIY users, such as small
cans and containers less than 5 lbs) because it does not contain
specifications for unique fittings for can taps and for these smaller
containers. Existing SNAP program regulations in appendix D to subpart
G of 40 CFR part 82 require the use of unique fittings for specific
purposes (e.g., high pressure-side service port, small can taps) for
each MVAC refrigerant, as submitted by the refrigerant manufacturer.
Before HFO-1234yf can be introduced in small containers typically used
by DIYers, the manufacturer must submit unique fittings to EPA, we must
conclude that they are unique, and we must issue new proposed and final
rules specifying those fittings. In addition, the final SNUR would not
allow distribution in commerce of products intended for use by a
consumer for the purposes of servicing, maintenance and disposal
involving HFO-1234yf until at least 90 days after submission of a SNUN.
These and other requirements ensure--to the extent possible, with the
information currently available to EPA--that HFO-1234yf has no greater
risk overall for human health and the environment than other available
refrigerants for MVAC.
    Under the final SNUR, it is necessary for EPA to receive and
complete its review of a significant new use notice (SNUN) with
additional information on consumer exposure risks before--if the Agency
so decides--HFO-1234yf may be manufactured, imported or processed for
the purpose of use in DIY servicing, with or without other
restrictions. We would also consider information in the SNUN before
issuing a final rule specifying unique fittings for use with small
containers of refrigerant.
    In comments EPA received on the proposed SNAP rule, the initial
direct final SNUR that was withdrawn and the proposed SNUR, no
commenters suggested making the provisions of the SNUR stricter or
suggested adding use conditions under the SNAP program for addressing
risks to consumers during DIY servicing. A number of commenters stated
that no restrictions were needed to address risks to consumers during
DIY servicing, while other commenters stated more broadly that EPA
should find HFO-1234yf unacceptable because of its toxicity risks. We
provided an additional opportunity for comment on the SNAP rule after
the direct final SNUR was issued (February 1, 2010; 75 FR 4083), in
response to a request to reopen the public comment period (EPA-HQ-OAR-
2008-0664-0077.1), in part to allow comment on the relationship between
these two rulemakings that both address HFO-1234yf. However, we do not
believe that the conditions of the final SNUR are necessary to the
determination that we are making here. As noted above, this final rule
does not allow for the servicing of HFO-1234yf from container sizes
that would be purchased by DIY users because of the lack of an approved
unique fitting for smaller containers. Further rulemaking under SNAP
will occur prior to such use and any risks can be addressed in that
rulemaking package. At that time, we will be able to fully consider the
impact of the final SNUR.
2. Flammability
    Comment: Five commenters stated that HFO-1234yf has a low
likelihood of ignition, especially under the conditions encountered in
an automotive application. One commenter stated that the mere presence
of high refrigerant concentrations does not contribute to a hazardous
condition because an ignition source of sufficient energy must also be
present. Another commenter disagreed with EPA's view that a
flammability risk exists. Other commenters stated that additional
review of the available information regarding flammability of HFO-
1234yf needs to be conducted. Some commenters stated that EPA should
consider restricting concentrations of HFO-1234yf to much lower
concentrations than to the lower flammability limit (LFL) of 6.2%.
    Response: The available evidence indicates that HFO-1234yf will not

present a significant risk of flammability and that any risk it poses
is not greater than the risk presented by other available alternatives.
For example, because of its higher LFL, its considerably higher minimum
ignition energy (5000 mJ to 10,000 mJ), and its slower flame speed (1.5
cm/s), HFO-1234yf is less flammable than HFC-152a, a substitute that
EPA has already found acceptable subject to use conditions.
    Further, an analysis conducted for SAE International's Cooperative
Research Program by Gradient Corporation (CRP, 2009) found that there
was a very low flammability risk (on order of 10-14
occurrences per operating hour or 1 occurrence in 100 years across the
entire U.S. fleet of passenger vehicles). This was due to the low
probability of achieving a concentration of HFO-1234yf above the LFL at
the same time as having a sufficiently high energy source to cause the
refrigerant to ignite. Further, even that low probability of ignition
of HFO-1234yf may be overstated, because it assumes that a vehicle
collision severe enough to crack open the evaporator (located under the
windshield and steering wheel) is not severe enough to crack the
windshield or windows that would hold refrigerant in the passenger
compartment. In a sensitivity analysis, the SAE CRP considered how the
flammability risk would change if a refrigerant release into the
passenger compartment only occurs in a collision causing damage to more
than the MVAC system. That analysis estimated that the risk of exposure
to an open flame would then be reduced by a factor of 23,000, to
approximately 4 x 10-19 occurrences per vehicle operating
hour (EPA-HQ-OAR-2008-0664-0056.2).
    For the reasons provided above in sections IV and VII.B of the
preamble, ``What are the final use conditions and why did EPA finalize
these use conditions?'' and ``Use conditions,'' EPA does not believe it
is necessary to establish a use condition limiting refrigerant
concentrations, whether at 6.2% or some other, lower value. We believe
the final use conditions sufficiently address flammability risks.
    Comment: Three commenters stated that HFO-1234yf is flammable and
that the proposed regulation does not offer any restrictions to protect
those persons handling HFO-1234yf, nor does it restrict its sale and
use by the general public.
    Response: The purpose of the use conditions is to ensure that HFO-
1234yf will not pose a greater risk to human health or the environment
than other available or potentially available substitutes. For all of
the reasons provided in sections IV and V above, EPA has determined
that HFO-1234yf will not pose a greater risk than other substitutes for
MVAC. As explained above, EPA proposed restricting concentrations of
the refrigerant below the LFL of 6.2% as a use condition. Based on
comments and additional analysis, EPA has concluded that it is not
necessary to require use conditions limiting refrigerant concentrations
to below the LFL; rather, the use conditions now specify design
parameters for MVAC systems and require an FMEA. This will ensure that
systems are designed to minimize risk not only from flammability, but
also from exposure to HF.
    We will address use by service personnel through a rulemaking under
section 609 of the CAA. Although these rules will further address
issues of interest to service personnel and others that might handle
HFO-1234yf used in MVAC systems, we note that our risk assessments of
use of HFO-1234yf found that significant flammability risks do not
exist for personnel installing the refrigerant at equipment
manufacture, professional servicing personnel, and personnel working
with automobiles at equipment end-of-life (EPA-HQ-OAR-2008-0664-0036
and -0038). Moreover, we note that an industry-sponsored analysis of
risks found the risk of ignition of HFO-1234yf to a technician is
extremely small, on the order of 10-26 occurrences per
working hour (EPA-HQ-OAR-2008-0664-0056.2).
    As we have explained above, this rule only addresses the use of
large containers for professional use (typically 20 lbs or larger) and
thus HFO-1234yf may not be used in small container sizes that would be
the type purchased by the general public. We will address the issue of
risk to DIY users through a future rulemaking under SNAP if we receive
a request for unique fittings for smaller containers from the
refrigerant manufacturer. We also are addressing risks to DIY users
through the Significant New Use Rule under the Toxic Substances Control
Act (October 27, 2010; 75 FR 65987).
    Comment: One commenter stated that compared with HFC-134a, the
explosion probability of HFO-1234yf is much higher based on testing
done at the Federal Institute for Materials Research and Testing
(Bundesanstalt f[uuml]r Materialforschung und-pr[uuml]fung, BAM). Other
commenters disagreed with those flammability conclusions, finding the
testing results to be expected but not representative of real-world use
in MVAC. These commenters stated that the flammability risks of HFO-
1234yf were not significant and that the mixtures of HFO-1234yf and
ethane used in the testing would not be seen in MVAC in actual
operations.
    Response: As explained above in section VII.B, we do not believe
that these tests are relevant for assessing the flammability risks of
HFO-1234yf as used in MVAC systems because they evaluated flammability
based on the presence of ethane, a substance that should not be present
in any situation that might cause flammability risks for MVAC systems.
3. Toxicity of Hydrogen Fluoride (HF)
    Comment: Two commenters stated that there is low risk due to
exposure to HF. One of these commenters stated that (1) for vehicles
that do not discontinue the use of the blower after collision, the risk
due to exposure to HF from use of HFO-1234yf is approximately twice the
risk with the current use of HFC-134a, and (2) for vehicles that
discontinue the use of the blower after collision, 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). The second
commenter stated that there is no need for concentration limits to
protect against exposure to HF because the risks from exposure to HF
from HFO-1234yf are similar to what would be experienced with HFC-134a.
One commenter also stated that concentrations of HF as low as 0.3 ppm
cause a sensation of irritation. The commenter stated that this
characteristic would deter someone from remaining exposed to excessive
concentrations from an open hood.
    Other commenters stated that there is a high probability of HF
generation in cars from HFO-1234yf. One commenter stated that the
flammability of HFO-1234yf makes the production of HF more likely and
increases the risk of HF exposure to vehicle passengers, to workers at
chemical facilities, automotive manufacturing facilities, vehicle
servicing facilities, and to the general public. Two commenters stated
that various health and safety concerns related to HF generation and
its toxicity are well studied and documented, and three commenters
stated that use of HFO-1234yf is unacceptable as there is increased
potential for HF exposure and related casualties.
    Response: EPA has considered the potential for generation of HF
from HFO-1234yf, including the SAE CRP's evaluation of scenarios that
might cause workplace and consumer exposure to HF (EPA-HQ-OAR-2008-
0664-0056.2). SAE CRP members conducted

tests to measure HF concentrations and to identify factors that were
most likely to lead to HF formation. One set of tests conducted in a
car found that HF measurements inside the passenger cabin were 35 ppm
or less (EPA-HQ-OAR-2008-0664-0056.2). This highest value occurred
during release of the entire charge of refrigerant of 1000 g into the
passenger cabin with ignition started by a butane lighter augmented
with an additional spark--a highly conservative scenario. (A more
typical charge would be 575 g, and it would be unlikely to have the
amount of ignition energy that occurred artificially in the experiment
with use of both a butane lighter and an additional spark source.) A
second set of tests focusing on HF in the engine compartment tried to
simulate a major rupture in the AC system that would release 12 g/s of
refrigerant across 5 cm onto an artificial hot surface at temperatures
of 450 [deg]C (typical of the exhaust manifold) and 700 [deg]C (most
extreme case), with the car hood in various positions. This testing
found HF concentrations as high as 120 ppm at the hot surface in the
engine compartment in the worst case, with interior passenger cabin
values of 40 to 80 ppm in the worst case (EPA-HQ-OAR-2008-0664-0056.2).
This test was conservative for the following reasons: The temperature
was high, representing extreme conditions; the refrigerant was released
extremely close to the hot surface; the hood was closed; and the
refrigerant ignited briefly. The other test trials under less extreme
conditions resulted in HF concentrations of a few ppm. The test trials
also found somewhat lower concentrations of HF generated during testing
of HFC-134a using the same procedures and apparatus, with maximum
concentration of 36 ppm in the engine compartment and concentrations of
less than 8 ppm in the passenger compartment in the worst case. The SAE
CRP selected an Acute Exposure Guideline Limit (AEGL)-2 \25\ of 95 ppm
over 10 minutes as its criterion for determining excessive risk. This
limit was developed to protect against irreversible health effects when
exposure remains below the limit of 95 ppm over 10 minutes, but short-
term discomfort or irritation could still occur. Thus, even assuming a
passenger inside a vehicle was exposed to HF at the highest level found
in the test of 80 ppm, exposure at this level would at worst cause
discomfort and irritation, rather than permanent or disabling health
effects.
---------------------------------------------------------------------------

    \25\ An AEGL-2 is intended to apply to an emergency situation
where someone would try to move away from the hazard in a short
period of time and may suffer some temporary irritation, but no
permanent health damage. Irreversible or disabling but non-fatal
health effects could occur between the AEGL-2 and the higher AEGL-3.
---------------------------------------------------------------------------

    For both HFO-1234yf and for HFC-134a, HF concentrations in the
passenger compartment fell between the level that would protect against
all adverse health effects (AEGL-1 of 1.0 ppm for 10 minutes to 8
hours) and the level that would protect against irreversible or
disabling health effects (AEGL-2 of 95 ppm over 10 minutes) (NRC,
2004). The SAE CRP concluded that the probability of such a worst case
event is on the order of 10-12 occurrences per operating
hour (EPA-HQ-OAR-2008-0664-0056.2). Commenters provided information
indicating that this level of risk for HF generation is the same order
of magnitude for both HFC-134a and for HFO-1234yf. EPA considers the
risk level presented by HFO-1234yf to be similar to that of the
refrigerant currently being used by automobile manufacturers, HFC-134a.
Therefore, there is no reason to regulate HFO-1234yf more stringently
to protect against HF exposure than for HFC-134a.
    Comment: One commenter stated that testing with HFOs commissioned
by the environmental organization Greenpeace in 2001 hinted at a
multitude of decomposition products with high reactivity. The commenter
stated that apparently even lubricants (polyalkylene glycol--PAG) break
down to HF when in contact with HFO-1234yf in a MVAC system. The
commenter further expressed that BAM testing showed that burning HFO-
1234yf resulted in concentrations of HF greater than 90 ppm in the
engine compartment. The commenter concluded that the tests prove that
in a standard system with standard charge (900 grams) and oil, the risk
for humans would be incalculable.
    Response: The commenter has not provided sufficient information on
the testing commissioned by Greenpeace in 2001 for the Agency to
determine what the results were or whether the testing conditions are
relevant to this action. Concerning the BAM testing, EPA has not seen a
testing report or a detailed description of the experimental method
that allows for a full evaluation. Based on the information provided by
the commenter, the temperature of the released substance reached 600
[deg]C and HF concentrations of over 90 ppm were measured in the engine
compartment. According to a risk assessment from an automobile
manufacturer, such a high temperature is unlikely and could only be
achieved on the exhaust manifold under heavy engine loads such as when
a vehicle is climbing a hill, and the temperature of the exhaust
manifold would drop in a minute or so during deceleration (EPA-HQ-OAR-
2008-0664-0081.1). It is not clear what the conditions were for the
study mentioned by the commenter. For example, it is not clear if the
refrigerant was mixed with compressor oil as it normally would be in an
MVAC; inclusion of oil with a relatively low flashpoint would be
expected to lead to ignition at lower temperatures (EPA-HQ-OAR-2008-
0664-0056.2; EPA-HQ-OAR-2008-0664-0118.1). It also is not clear if the
compressor fan was operating during the test. During normal vehicle
operation, the fan would cool down the compressor and the engine
compartment, avoiding the temperature of 600 [deg]C on hot surfaces in
the engine.
    Other tests have found that HF concentrations in the engine
compartment were approximately 5 ppm or less and only in the worst case
(hot surface temperature of 700 [deg]C, closed hood on engine
compartment) did HF concentrations attain a value of approximately 120
ppm in the engine compartment (OAR-2008-0664-0056.2). This level is
slightly higher than the AEGL-2 of 95 ppm on a 10-minute average and is
lower than the AEGL-3 for HF of 170 ppm on a 10-minute average, the
value that would protect against life-threatening exposure but would
not necessarily prevent long-term health effects. However, we note that
we do not anticipate any circumstance where a person would be exposed
to these levels in an engine compartment because such conditions would
not occur during vehicle servicing, but rather during vehicle
operation. Further, in the case of a collision resulting in a fire, we
would expect that professional first responders have training in
chemical hazards and possess appropriate gear which would prevent them
from receiving HF exposures above health-based limits (EPA-HQ-OAR-2008-
0664-0056.2) and an interested by-stander would quickly back away from
a fire or from irritating HF vapors, thus preventing excessive HF
exposure. The concentration measured in the passenger compartment in
the same worst-case situation was in the range of 40 to 80 ppm, less
than the concentration in the engine compartment and less than the
AEGL-2 intended to protect against long-term health effects. Thus, we
disagree with the commenter's assertion that HF exposures from thermal
decomposition or combustion of refrigerant would be likely to result in
fatalities. We further

note that the HF concentrations found in the passenger compartment were
lower than the health-based limit, the AEGL-2 of 95 ppm over 10
minutes.
    We also note that the risks presented by HFO-1234yf are not
significantly different than the risk posed by HFC-134a, the
refrigerant currently in use in MVAC systems. Mixtures of HFC-134a and
compressor oil also combust and generate HF. Testing performed using
HFC-134a under worst-case conditions in the engine compartment (hot
surface temperature of 700 [deg]C, closed hood on engine compartment)
found HF concentrations as high as 36 ppm in the engine compartment and
2 to 8 ppm in the passenger compartment. The amount of HF generated
from a typical charge of HFC-134a, if it all burned or decomposed,
could be even more than for the expected charge of HFO-1234yf because
charge sizes using HFO-1234yf are expected to be smaller (EPA-HQ-OAR-
2008-0664-0056.2). The SAE CRP considered potential risks of HF
exposure from both HFO-1234yf and from HFC-134a. Both presented
potential risks on the order of 10-12 occurrences per
operating hour (EPA-HQ-OAR-2008-0664-0056.2, -0096.1). This corresponds
to less than one case per year across the entire fleet of motor
vehicles in the U.S. Although there is no specific testing data on HF
production from HFC-152a, another acceptable refrigerant for MVAC,
since this compound contains fluorine, it presents risks of HF
generation as well. As discussed above in Section IV of the preamble,
we are not requiring specific use conditions that regulate production
of HF, either directly or indirectly, because of the low level of risk.
However, the final use conditions in this rule address the risks of HF
production, as well as risks of flammability, by requiring certain
design safety features of MVAC systems using HFO-1234yf and by
requiring risk analysis for each car model through FMEAs.
    Comment: A commenter provided results from a test by IBExU on the
decomposition of HFO-1234yf under heat (EPA-HQ-OAR-2008-0664-0053.3).
This commenter strongly warned against a decision in favor of HFO-
1234yf because it would form highly toxic HF when burning. Three
commenters disagreed that the results of the IBExU testing were
relevant because test conditions did not represent realistic
conditions. One commenter said that the SAE risk assessment, which used
actual vehicle test data for HF formation, found that actual HF
formation rates are far below the levels [from the IBExU test results]
cited by the first commenter, the Federal Environmental Agency
(Umweltbundesamt--UBA).
    Response: The IBExU testing of HF generation from HFO-1234yf is not
relevant to assessing the risks of HFO-1234yf as a refrigerant in MVAC.
Laboratory tests concerning the nature of HF generation on hot surfaces
found that this depends on the contact time of reactants on the hot
surface, the temperature of the hot surface and the movement of
refrigerant in diluted concentrations due to airflow (EPA-HQ-OAR-2008-
0664-0056.2; EPA-HQ-OAR-2008-0664-0116.2). The IBExU testing involved
heating the refrigerant steadily in a sealed flask. Thus, the contact
time in that test was far greater than would occur in an engine
compartment and the movement of refrigerant in that test was
essentially zero, unlike in an engine compartment where there would be
constant air movement.
    Comment: Another test from BAM reported by UBA examined HF
formation from HFO-1234yf and from HFC-134a (EPA-HQ-OAR-2008-0664-
0080.1). Fifty grams of refrigerant was streamed through a hole of 2 mm
diameter onto a hot metal surface. The study found that pure HFO-1234yf
exploded on the hot surface whereas pure HFC-134a did not. The study
also found that when HFO-1234yf was mixed with 3% oil, it exploded at
600 [deg]C. The commenter stated that handling of HFO-1234yf in the
presence of hot metal surfaces results in HF formation in
concentrations far above allowed workplace concentrations.
    Response: These results are not consistent with results from hot-
plate tests conducted by an automobile manufacturer and by a chemical
manufacturer for the SAE CRP (EPA-HQ-OAR-2008-0664-0056.2; EPA-HQ-OAR-
2008-0664-0115.1). Those manufacturers found that neither HFO-1234yf
nor HFC-134a alone ignited at 900 [deg]C. One of these tests found that
HFO-1234yf mixed with PAG oil combusted starting at 730 [deg]C, while
HFC-134a mixed with PAG oil ignited at 800 [deg]C and above; the other
test observed no ignition of a blend of each refrigerant with PAG oil
at 800 [deg]C, but both blends ignited at 900 [deg]C. Based on the lack
of reproducibility of the specific ignition temperature, it appears
that the specific ignition temperature may depend on variables in the
testing (e.g., flash point of the oil used, amount of mixture used,
angle of application, and air flow available). This information also
shows that mixtures of refrigerant with compressor oil can combust at
lower temperatures than pure refrigerant and that mixtures of HFO-
1234yf and oil and mixtures of HFC-134a and oil present similar risks
of ignition and HF generation. Thus, we concluded that the risks of
toxicity from HF exposure due to combustion or decomposition of HFO-
1234yf are comparable to those from HFC-134a.
    Further, the risks from toxicity of HF posed by both refrigerants
are small. The SAE CRP estimates this risk on the order of
10-12 cases per operating hour (EPA-HQ-OAR-2008-0664-
0086.1). This is equivalent to less than one event per year across the
entire fleet of motor vehicles in the U.S. For comparison, this is less
than one ten-thousandth the risk of a highway vehicle fire and one
fortieth or less of the risk of a fatality from deployment of an airbag
during a vehicle collision (EPA-HQ-OAR-2008-0664-0056.2).

E. Retrofit Usage

    Comment: Several commenters stated that HFO-1234yf should be
allowed initially in new vehicles but should not be used to retrofit
vehicles using HFC-134a, or at least not unless there are industry
standards to guide such a process. Other commenters stated that it is
critical to allow a natural phase-out of the fleet of cars using HFC-
134a as the refrigerant, rather than requiring retrofitting existing
cars with HFO-1234yf. A commenter expressed concern that retrofitting
of HFC-134a MVAC systems with HFO-1234yf would result in cases of
cross-contamination of refrigerant, while another commenter contested
this statement and found it unsupported. Other commenters opposed
obstacles that would prevent older MVACs from being retrofitted to the
new refrigerant. These commenters mentioned the potential for
greenhouse gas benefits when retrofitting systems currently using HFC-
134a with HFO-1234yf.
    Response: The submitter did not request review of HFO-1234yf for
retrofitting vehicles and thus EPA did not review HFO-1234yf as
acceptable (or acceptable subject to use conditions) for retrofitting
in MVAC in this rulemaking. Consistent with the request submitted to
the Agency, we proposed to find HFO-1234yf acceptable for use subject
to use conditions in new MVAC systems and evaluated its risks only for
use in new systems. We will consider the retrofit use of HFO-1234yf in
MVAC systems if we receive a submission that specifically addresses
retrofitting and the risks that are unique to retrofitting. In response
to the commenter who raised a concern about a ``phase-out'' of HFC-134a
and the potential that we would ``require'' use of HFO-1234yf, we

note that our rulemakings under SNAP do not require use of any specific
substitute. Rather, under SNAP, we have established lists of
substitutes that are acceptable for use in various end-uses (such as
for MVACs) and end-users are free to choose which substitute to use,
but must do so consistent with any use conditions that apply. As stated
in the rule establishing the SNAP program, ``The Agency * * * does not
want to intercede in the market's choice of available substitutes,
unless a substitute has been proposed or is being used that is clearly
more harmful to human health and the environment than other
alternatives.'' 59 FR 13046, March 18, 1994. We further note that this
rulemaking does not change the status of HFC-134a, which remains an
acceptable substitute for use in MVACs, subject to use conditions.

F. Use by ``Do-it-Yourselfers''

    Comment: Some commenters raised concerns about EPA's statements in
the proposed rule about potential health effects that might occur
without professional training and the use of CAA Section 609 certified
equipment. These commenters stated that the studies and testing in the
docket support a finding that use of HFO-1234yf by non-professionals is
safe and do not offer valid technical support for EPA's concerns.
    Response: EPA's risk assessment and risk screen both indicated that
worst-case exposure levels expected during servicing by do-it-
yourselfers are of potential concern (EPA-HQ-OAR-2008-0664-0036 and
EPA-HQ-OAR-2008-0664-0038). In both documents, this was based upon
estimated exposure levels from a 2008 risk assessment by Gradient
Corporation for the SAE CRP (EPA-HQ-OAR-2008-0664-0008). In EPA's risk
assessment (EPA-HQ-OAR-2008-0664-0036), we found that the level that
EPA determined did not cause health effects in laboratory animals might
be only 2 to 3 times higher than the exposure predicted for that use
(the ``margin of exposure''). Our risk assessment indicated a higher,
more protective margin of exposure of at least 30 was needed to account
for uncertainty in the extrapolation from animals to humans and for
variability in the human population. In other words, we found that
based on worst-case assumptions, a do-it-yourselfer's exposure could be
10 or more times the level that EPA considered safe. The margin of
exposure was calculated using a conservative estimated exposure level
of 45,000 ppm over 30 minutes and a human equivalent concentration of
98,211 ppm from a no-observed adverse effect level that we selected as
the point of departure for risk assessment (EPA-HQ-OAR-2008-0664-0036).
    However, under this final rule, unique fittings have only been
submitted for servicing fittings for the high-side and low-side ports
and for large containers of HFO-1234yf and thus the acceptability
listing is limited to use of HFO-1234yf with the unique fittings
specified (e.g., for large containers of 20 pounds or more). We expect
these containers would not be purchased by DIYers because of their
expense ($800 or more per container) and because they would contain
enough refrigerant for 10 charges or more. We will continue to review
the issue of safe use for DIYers if and when we are requested to review
unique fittings for a smaller container size. In addition, EPA is
further addressing the issue of risks to DIYers in the Significant New
Use Rule for 1-propene-2,3,3,3-tetrafluoro- (75 FR 65987, October 27,
2010). This SNUR requires submission of a SNUN at least 90 days before
sale or distribution of products intended for use by a consumer for the
purpose of servicing, maintenance and disposal involving HFO-1234yf.
    EPA's proposed rule on the use of HFO-1234yf as a substitute for
CFC-12 in new MVAC systems did not propose to establish use conditions
for servicing vehicles by certified professionals, but our analyses
indicate that there is not significant risk to certified professionals,
because HFC-134a, which is currently used in most MVAC systems,
presents similar risks and professionals have the knowledge and
equipment to mitigate any risks. We plan to further address servicing
by professionals when we develop a new rule under section 609 of the
Clean Air Act for servicing and maintenance of MVAC systems.
    Comment: Some commenters supported prohibiting sale of HFO-1234yf
in small containers. Other commenters stated that only certified
technicians should be allowed to purchase and use refrigerants,
including HFC-134a and HFO-1234yf. Other commenters found no data to
support restrictions on the sale of HFO-1234yf to non-professionals.
    Response: As noted previously, the submission only addressed unique
fittings for large containers (e.g., 20 lbs or larger) of HFO-1234yf.
If anyone is interested in using HFO-1234yf in small cans or other
small containers, they would need to contact the refrigerant
manufacturer to submit unique fittings for approval under the SNAP
program. Thus, under this final rule, we believe that only certified
technicians will purchase HFO-1234yf because the larger containers are
likely to be prohibitively expensive for individuals performing DIY
servicing ($800 or more for a 20 lb cylinder) and are likely to be too
large for most individuals to use, containing enough refrigerant for 10
or more charges.
    We also note that in a separate final rule under the authority of
TSCA (October 27, 2010; 75 FR 65987), EPA requires among other things,
that notice must be given to EPA 90 days before (1) HFO-1234yf is used
commercially other than in new passenger cars and vehicles in which the
charging of motor vehicle air conditioning systems with HFO-1234yf was
done by the motor vehicle OEM or (2) sale or distribution of products
intended for use by a consumer for the purpose of servicing,
maintenance and disposal involving HFO-1234yf.
    Comment: A commenter stated that banning DIY use of HFO-1234yf will
mean that car owners will be forced to have professionals perform
service work on their AC systems at a significantly higher cost. This
commenter stated that millions of lower-income motorists may be forced
to go without air conditioning each year or may seek out lower-cost
alternatives such as propane or HFC-152a.
    Response: While this final rule effectively prohibits DIY use
because the final use conditions do not include unique fittings
allowing for use with small refrigerant containers, we are not making
any final determination about whether HFO-1234yf may be safely used by
DIYers. As we noted above, we have not yet received a submission for
DIY use or received unique fittings for small containers from the
manufacturer, but would evaluate such submissions when we receive one.
We note that because it is unlikely that any cars will have MVAC
systems with HFO-1234yf before the 2013 model year, we believe the
availability of small containers for DIY use will not be of concern
until such cars are sold and there is a need to recharge a new MVAC
system on a model year 2013 vehicle. The separate final Significant New
Use Rule that the Agency has issued under TSCA (75 FR 65987; October
27, 2010) requires submission of a Significant New Use Notice at least
90 days before sale or distribution of products intended for DIY use.
    With respect to the commenter who suggests that some people may
seek lower cost alternatives, presumably to repair an existing MVAC, we
note that under current EPA regulations in appendix D to subpart G of
40 CFR part 82, it is not legal to top-off the

refrigerant in an MVAC system with a different substitute refrigerant.

G. Servicing Issues

    Comment: Several commenters stated that appropriate training and
certification should be required to purchase HFO-1234yf for use in
MVACs. Four commenters also stated that the final regulation should
include a provision requiring proof of certification in order to
purchase HFO-1234yf, and recommended that current AC systems tests
(i.e., for CAA section 609 certification) be updated.
    Some commenters disagreed with EPA's statement that HFO-1234yf may
cause serious health effects when used in servicing and maintaining
MVACs without professional training. Another commenter stated that EPA
is limiting productivity by only allowing dealerships to perform
refrigerant maintenance, and that independent MVAC service shops should
be allowed to be certified. The commenter also questioned who will
monitor ``certified'' technicians employed by dealerships that may do
work on the side. A commenter representing automobile dealerships
specifically opposed mandatory requirements for certification of
technicians because of potential costs and burden on small businesses.
    Response: As background for the public comments, we note that under
EPA's regulations implementing section 609, one must be a section 609
certified technician in order to purchase CFC-12 or other ODS for use
in MVAC (40 CFR 82.34(b)). Section 609(e) of the CAA itself
specifically prohibits sale of small containers less than 20 pounds
with Class I or Class II substances suitable for use as a refrigerant
in MVAC, except for individuals performing service for consideration in
compliance with section 609. However, there is no comparable
restriction on the sale of HFC-134a or on other substitutes for MVAC
that do not contain Class I or Class II ODS, such as HFO-1234yf.
    In the NPRM (74 FR 53449), EPA stated that any specific training
and certification requirements would be adopted through a rulemaking
under the authority of CAA section 609 and would be codified in subpart
B of 40 CFR part 82, which contains the regulations implementing
section 609. We will address concerns regarding certification and
training requirements during that separate rulemaking process. We note,
however, that the CAA itself mandates that persons performing service
for consideration that involve the refrigerant must be properly trained
and certified. Furthermore, as noted previously, we believe that there
is not a significant health risk to professionals from HFO-1234yf
because they will have the knowledge and equipment to mitigate any
risks. Also, because HFC-134a presents similar risks to HFO-1234yf, and
the flammability risks of HFO-1234yf are less than those for HFC-152a,
the health risks of HFO-1234yf are not significantly greater than those
of other available substitutes.
    With regard to whether independent service shops could service
MVACs with HFO-1234yf or whether service would be limited to
``dealerships,'' we note that neither this rule nor any other CAA
regulation would limit servicing to dealerships. The comment may
concern the withdrawn SNUR, 75 FR 4983 (February 1, 2010), which
referred to the ``original equipment manufacturer''; the commenter may
have interpreted this term to mean an automobile dealership. The final
SNUR (October 27, 2010; 75 FR 65987) requires a significant new use
notice to EPA at least 90 days before ``commercial use other than in
new passenger cars and vehicles in which the charging of motor vehicle
air conditioning systems with the PMN substance [HFO-1234yf] was done
by the motor vehicle original equipment manufacturer.'' This
requirement restricts commercial use of HFO-1234yf to use for vehicles
that were initially charged with HFO-1234yf by the automobile's
manufacturer, as opposed to allowing commercial use of HFO-1234yf for
vehicles initially charged with a different refrigerant. The term
``original equipment manufacturer'' refers to the automobile
manufacturer, not to dealerships.
    Comment: Commenters indicated that SAE International is developing
standards for safety and servicing of alternative refrigerant HFO-
1234yf MVAC systems. Another commenter stated that there are
appropriate mechanisms within the industry for training. One commenter
representing automobile dealerships objected to mandatory Section 609
technician certification and training for use of HFO-1234yf, stating
that because dealerships already train technicians on flammable
substances in accordance with hazard communication standards of the
Occupational Safety and Health Administration (OSHA), and since the
risks associated with HFO-1234yf are similar to those that already
exist in MVAC service facilities, mandatory training and proof of
training is not necessary. To enable training pursuant to the OSHA
hazard communication standard, the commenter stated that MVAC system
and refrigerant suppliers should provide dealerships with sufficient
information on the hazards posed by HFO-1234yf.
    Response: EPA is issuing use conditions in this final rule that
reference relevant SAE technical standards on safety. This rule does
not, however, include a use condition requiring technician training and
does not refer to specific training standards. We agree with the
commenter that current technician training generally should be
sufficient to ensure that professional technicians will use HFO-1234yf
safely. Although this SNAP determination does not contain a use
condition regarding technician training, as noted above, section 609 of
the CAA requires technician training for persons servicing for
consideration. EPA will consider in a separate rulemaking under section
609, whether it is necessary to modify our existing regulations under
section 609 to include additional specifications for HFO-1234yf.
    Comment: A commenter representing automobile dealerships opposed
mandatory requirements for recycling and containment of the refrigerant
because of potential costs and minimal environmental benefits.
    Response: This rulemaking does not impose requirements for
recycling or containment of the refrigerant. A separate rulemaking
under CAA section 609 will address practices required in the servicing
of MVAC systems using HFO-1234yf, including recycling and recovery.
Further, EPA notes that Section 608 of the CAA prohibits the
intentional release of any refrigerant during the maintenance, repair,
service, or disposal of refrigeration and air conditioning equipment,
unless the Administrator determines through rulemaking that such
release does not pose a threat to the environment. We have not made
such a determination for HFO-1234yf.

H. Cost, Availability, and Small Business Impacts

    Comment: One late commenter stated that there was insufficient
information in the record on the cost, terms of availability and
anticipated market share of HFO-1234yf for EPA to make the required
statutory findings that HFO-1234yf ``reduces the overall risk to human
health and the environment'' by comparison to other alternatives that
are already available. The commenter stated that this information is
necessary in order for EPA to assess anticipated environmental effects
adequately. The same commenter stated that EPA's environmental analysis
is based on price assumptions that were not disclosed and are no longer
valid, and thus, EPA should subpoena the

information from the manufacturer and reopen the public comment period.
    Response: EPA believes that there was sufficient information in the
record at the time of proposal for us to complete a meaningful
environmental analysis, even in the absence of definitive cost
information. At the time of proposal, we had available both estimates
from a trade magazine provided by the manufacturer (Weissler, 2008), as
well as estimates of price provided in the initial submission from the
manufacturer (EPA-HQ-OAR-2008-0664-0013). The estimates of price
provided by the manufacturer were claimed as confidential business
information and thus were not available in the record to the public.
    We typically use this type of information for purposes of
determining market penetration for a particular substance, so that we
can evaluate how much of the substitute will likely be used and thus
the environmental risks it might pose. In this case, however, because
the automobile industry tends to prefer use of a single substitute,
information on the cost of the substitute was not critical to our
analysis. Thus, in conducting our environmental analysis, we took a
conservative approach, assuming that all new MVAC systems began using
HFO-1234yf by 2020 (i.e., full market penetration). We also considered
an even more conservative scenario, in which HFO-1234yf would be the
only refrigerant used for stationary air conditioning and for
refrigeration as of 2020, as well as for MVAC. Even with these highly
conservative assumptions, we found that there would not be sufficient
negative environmental impacts due to emissions of HFO-1234yf to
warrant finding it unacceptable.
    In the proposal, we mentioned a cost estimate for HFO-1234yf of
$40-$60/lb (Weissler, 2008). More recently, the first automobile
manufacturer announcing its intention to use HFO-1234yf confirmed that
this range does not underestimate prices of HFO-1234yf and is
consistent with the manufacturer's long-term purchase contracts
(Sciance, 2010). Thus, the most recent information shows costs to be
similar to those we considered at the time of proposal. This data
contradicts the late commenter's assertion that the manufacturer's
effective monopoly would result in significantly different, higher
costs that would invalidate EPA's earlier analysis. In any event,
assuming that costs were higher as suggested by the commenter, then we
expect that use of HFO-1234yf would be less than assumed for our health
and environmental risk analysis. As mentioned in the proposal,
emissions, and thus the resulting environmental effects such as impacts
on local air quality or on production of TFA, would be expected to be
less under a scenario with higher prices and less use of HFO-1234yf.
Our analysis assumes widespread use and thus its results would be
protective.
    We note that where a new chemical is introduced, there is some
uncertainty in the price. At best, the manufacturer can provide rough
estimates of price and of market share before the chemical is produced
in commercial quantities and becomes subject to supply and demand
pressures. EPA's requirement for information on cost, anticipated
availability in the market, and anticipated market share (40 CFR
82.178(a)(14) through (16)) should not be construed as requiring
precise, detailed cost estimates based upon a well-defined methodology.
As noted above, we use these numbers for the purposes of predicting
market penetration and thus how much of a particular substitute might
be used and thus pose an environmental risk. As we did for HFO-1234yf,
we typically take an environmentally-protective approach to our
evaluation, assuming use at least as high as that the cost and
availability information may indicate.
    Comment: A late commenter stated that the information in the record
is insufficient for EPA to make a statutory finding that HFO-1234yf is
``currently or potentially available.'' The commenter stated that a
previous decision by the United States Court of Appeals for the
District of Columbia Circuit (Honeywell International, Inc. v. EPA, 374
F.3d 1363 (D.C. Cir. 2004)) implied that an interpretation of the term
``available'' in CAA section 612(c)(2) could potentially consider
economic factors if EPA adopted such an approach as a reasonable
interpretation of the statutory language. The commenter states that EPA
should obtain information as to the anticipated cost of HFO-1234yf if
the manufacturer does not grant licenses to produce.
    Response: The CAA does not require that EPA find a substitute to be
available or potentially available when finding it acceptable. Section
612(c) states: ``* * * It shall be unlawful to replace any class I or
class II substance with any substitute substance which the
Administrator determines may present adverse effects to human health or
the environment, where the Administrator has identified an alternative
to such replacement that--reduces the overall risk to human health and
the environment; and is currently or potentially available. * * *''
    This section makes clear that it is not the substitute under review
that must be available or potentially available, but rather alternative
replacements for ODS that EPA determines pose less overall risk to
human health and the environment than the substitute being reviewed.
Thus, if there are alternatives to the substance under review that are
currently or potentially available and that pose less risk, EPA cannot
find the substitute under review acceptable. Section 612(c) establishes
no requirement that EPA must determine that the substitute under review
is ``available.'' See also 40 CFR 82.180(b) (describing types of
listing decisions EPA can make in reviewing substitutes \26\). We note
that even if EPA was required to determine that the substitute under
review is available or potentially available before it could make an
acceptability determination, we believe that the available information
supports that HFO-1234yf is potentially available. EPA's definition of
``potentially available'' at 40 CFR 82.172 provides that ``potentially
available'' is defined as any alternative for which adequate health,
safety, and environmental data, as required for the SNAP notification
process, exist to make a determination of acceptability, and which the
Agency reasonably believes to be technically feasible, even if not all
testing has yet been completed and the alternative is not yet produced
or sold. This definition makes explicit that it is not necessary to
have perfect information on a substitute nor is it necessary for the
substitute to be produced or sold in order for EPA to consider it
``potentially available.'' Instead, it is necessary for EPA to find the
health, safety and environmental data adequate to make a determination
of acceptability, and for the Agency to reasonably believe that the
alternative is ``technically feasible,'' in order for the alternative
to be potentially available. We believe the record contains adequate
information showing that HFO-1234yf

is potentially available. The manufacturer has submitted the
information required under 40 CFR 82.178 (e.g., pre-manufacture notice
form and TSCA/SNAP addendum form containing: Name and description of
the substitute, physical and chemical information, information on ODP
and global warming impacts, toxicity data, data on environmental fate
and transport, flammability, exposure, cost and estimated production).
The submitter has also provided unique fittings as required under
appendix D to subpart G of 40 CFR part 82. Thus, we believe that there
is ``adequate health, safety, and environmental data.'' Even if the
commenter were correct about claims that higher costs would result if
the manufacturer does not grant licenses for production, as discussed
above, this does not affect the adequacy of the health, safety, and
environmental data for HFO-1234yf, because we have protectively assumed
widespread use that would result in more emissions and greater
environmental impacts. In addition, based on the experimental work
conducted by the automobile industry, we reasonably believe that HFO-
1234yf is technically feasible as a refrigerant. Thus, HFO-1234yf would
still be ``potentially available'' under the SNAP program's definition.
---------------------------------------------------------------------------

    \26\ The regulations for the SNAP program include cost and
availability as one of the criteria for review as to whether a
substitute is acceptable or unacceptable as a replacement for ozone
depleting substances (82.180(a)(7)(vii)), along with a number of
criteria for different aspects of health and environmental impacts.
Cost and availability are included as criteria because they affect
assumptions we may make about a substitute regarding its risks,
i.e., we need to know its cost and availability so we can make
assumptions about the risk it might pose. In this case, we assumed
that HFO-1234yf would be used widely across the industry in new
MVACs because widespread use of a single refrigerant in new car
models has been the industry practice with MVAC systems. Thus, more
detail on cost and availability of the substitute was not necessary
in order to identify assumptions we should make for estimating risk.
---------------------------------------------------------------------------

    One commenter points to Honeywell International, Inc. v. EPA, 374
F.3d 1363 in urging EPA to explicitly include cost as a consideration
in determining whether a substitute is ``potentially available.'' In
that case, the court vacated and remanded a SNAP decision in which EPA
listed a foam blowing substitute as acceptable subject to ``narrowed
use limits'' on the basis that for some niche foam blowing uses, the
substitutes that were already listed as acceptable might not be
available. Under the narrowed use limits, the end-user would need to
demonstrate and document that other substitutes were not technically
feasible for a particular use. The court vacated and remanded EPA's
rule on the basis that EPA had considered cost in concluding that
already listed substitutes might not be available based on
``technical'' feasibility, and that EPA had not attempted to justify
the rule on the ground that the statute allows it to consider economic
factors in making its SNAP determinations. The court left open the
question of whether EPA could attempt to interpret the term
``available'' in section 612(c) as allowing for consideration of costs.
    Again, we note that ``available or potentially available'' applies
only to the substitutes against which the substitute at issue is being
compared. The Agency has not decided whether consideration of the cost
of other substitutes should be a factor to consider in determining
whether they are available or potentially available and thus should (or
should not) be used for comparison to a substitute under review.
However, we note that for purposes of the substitute under review, the
Agency firmly believes that cost should not be the primary or sole
basis for finding a substitute unacceptable. EPA's role is to determine
the health and environmental risk associated with the use of
substitutes and the market should serve to address the issue of costs.
Costs will necessarily be a factor considered by the automobile
manufacturers in deciding which substitute to use.
    Comment: Two commenters stated that EPA needed to perform further
analysis on the potential small business impacts and costs of EPA's
regulations and the introduction of HFO-1234yf. A commenter
representing recyclers of automobiles and scrap metal expressed concern
about the regulatory burden and costs that automotive recyclers are
likely to incur if they must manage flammable refrigerants that are
regulated as hazardous waste under EPA's regulations implementing the
Resource Conservation and Recovery Act (RCRA). The same commenter also
suggests that the RCRA subtitle C regulations would need to be changed
to alleviate the hazardous-waste management requirements for handling
HFO-1234yf. The other commenter mentioned the costs to service and
repair shops, end-of-life vehicle recyclers, and automobile
dealerships, and stated that EPA needed to analyze costs to these small
businesses under the Regulatory Flexibility Act (RFA). This latter
commenter stated that EPA should determine if a significant change in
price and supply expectations would affect the way that these
businesses handle and deal with automobile repairs and recycling.
    Response: The RFA applies only when there are small entities
subject to the requirements of the proposed or final rule. 5 U.S.C.
Sec.  604(a)(3). We believe the potential burden of complying with RCRA
regulations placed on those recycling or recovering a substitute is
generally not pertinent to a decision of whether HFO-1234yf should be
found acceptable under SNAP. To the extent the commenters are
suggesting that we must evaluate such costs for purposes of the
Regulatory Flexibility Act, we note that under the RFA we evaluate
costs imposed by the enforceable regulations being promulgated. To the
extent the costs referred to by the commenter are already imposed under
RCRA, they would not be new costs, but costs associated with the
relevant RCRA regulations. Moreover, under this SNAP final rule, EPA is
not requiring the use of HFO-1234yf, and thus the costs associated with
its use are not due to enforceable regulatory requirements under SNAP.
To the extent there are enforceable requirements for those persons who
choose to use this new substitute, those requirements (the ``use
conditions'') apply primarily to manufacturers of automobiles and MVAC
systems, because they concern design of MVAC systems. The one use
condition of the rule that applies to servicing of MVAC systems, and
thus, could apply to small businesses, is the requirement for specific
unique service fittings. However, EPA's existing SNAP regulations at
appendix D to subpart G of 40 CFR part 82 already require unique
service fittings as specified by the refrigerant manufacturer. Thus,
the costs of purchasing new unique fittings for this refrigerant are
imposed by the pre-existing regulation. This rule specifies the
requirements for the type of unique fitting, in accordance with the
fittings provided to EPA by the manufacturer. These fittings are part
of the SAE J639 standard. It is not clear that there would be any cost
differential between these specific unique fittings and others that the
automotive industry could adopt instead. For these reasons, EPA is able
to certify that this regulation will not create a significant impact on
a significant number of small entities.
    Regulations concerning disposal of refrigerant from MVAC systems
and other refrigerant-containing appliances under section 608 of the
CAA are at subpart F of 40 CFR part 82. Cost and benefit estimates for
these regulations are at http://www.regulations.gov, docket EPA-HQ-OAR-
2003-0167. EPA notes that there may be costs of servicing or of
disposal (end-of-life) to small businesses under future regulations
under section 609 or 608 of the CAA. We will conduct an analysis of
such costs, and any potential significant impacts on small entities, as
necessary, as part of those future rulemakings.
    Comment: A commenter stated that to comply with requirements of the
Unfunded Mandates Reform Act (UMRA), EPA needed to perform further
analysis on the potential costs of EPA's SNAP regulations for HFO-
1234yf to determine if the rule would result in the expenditure of $100
million or more per year by the private sector. In particular, the
commenter stated that EPA must obtain more information on pricing and

the effect of the manufacturer's patent to analyze this.
    Response: UMRA applies only to ``enforceable duties'' imposed on
State, local, and Tribal governments or on the private sector. The SNAP
rule does not impose duties on governments. As we have noted
previously, the SNAP program does not mandate the use of any specific
substitute for ozone depleting substances. Rather, through this action,
we are expanding the choices of MVAC refrigerants available to the
private sector. The issue raised by the commenter concerning the cost
of the refrigerant and the effect of the manufacturer's patent on
pricing is not related to any requirement of the rule, and thus, EPA is
not required to consider that cost under UMRA.

VIII. 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 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 at subpart G of 40 CFR part 82.
3. Petition Process
    Section 612(d) grants the right to any person to petition EPA to
add a substance to, 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?

    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 (subpart G of 40 CFR
part 82). These sectors include: Refrigeration and air conditioning;
foam blowing; cleaning solvents; fire suppression and explosion
protection; sterilants; aerosols; adhesives, coatings and inks; and
tobacco expansion. These sectors compose the principal industrial
sectors that historically consumed the largest volumes of ODS.
    Section 612 of the CAA requires EPA to list as acceptable only
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 plans to market or produce 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. This requirement applies to the person planning to
introduce the substitute into interstate commerce,\27\ typically
chemical manufacturers, but may also include importers, formulators,
equipment manufacturers, or end-users \28\ when they are responsible
for introducing a substitute into commerce.
---------------------------------------------------------------------------

    \27\ 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.
    \28\ 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.
---------------------------------------------------------------------------

    The Agency has identified four possible decision categories for
substitutes: acceptable; acceptable subject to use conditions;
acceptable subject to narrowed use limits; and unacceptable. 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. It
is illegal to replace an ODS with a substitute listed as unacceptable,
unless certain exceptions (e.g., test marketing, research and
development) provided by the regulation are met.
    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.
    For some substitutes, the Agency may permit a narrowed 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 the substitute in
an unacceptable manner and is in violation of section 612 of the CAA
and EPA's SNAP regulations.
    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 decisions concerning substitutes that
are deemed acceptable with no restrictions in ``notices of
acceptability,'' rather than as proposed and final rules. As described
in the rule initially implementing the SNAP program (59 FR 13044), 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 http://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 subpart G of 40 CFR part 82.
A complete chronology of SNAP decisions and the appropriate citations
are found at http://www.epa.gov/ozone/snap/chron.html.

IX. Statutory and Executive Order Reviews

A. Executive Order 12866: Regulatory Planning and 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 EO 12866 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.
Today's action is an Agency determination. It contains no new
requirements for reporting. The only new recordkeeping requirement
involves customary business practice. Today's rule requires minimal
record-keeping of studies done to ensure that MVAC systems using HFO-
1234yf meet the requirements set forth in this rule. Because it is
customary business practice that OEMs conduct and keep on file Failure
Mode and Effect Analysis (FMEA) on any potentially hazardous part or
system from the beginning of production of a car model until three or
more years 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; for NAICS code 336111 (Automobile manufacturing), a small
business has < 1000 employees; for NAICS code 336391 (Motor Vehicle
Air-Conditioning Manufacturing), a small business has < 750 employees;
(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 today's final rule on
small entities, I certify that this action will not have a significant
adverse economic impact on a substantial number of small entities. The
only new requirement on small entities in this final rule is a
requirement specifying the type of unique service fittings required
when servicing MVAC systems using the refrigerant HFO-1234yf. Existing
regulations at appendix D to subpart G of 40 CFR part 82 already
require that there be unique service fittings for each refrigerant used
in MVAC systems. Thus, the costs of purchasing new unique fittings for
this refrigerant have already been imposed by the pre-existing
regulation. This rule specifies the requirements for which type of
unique fitting, in accordance with the fittings provided to EPA by the
manufacturer. These fittings are part of the SAE J639 standard. It is
not clear that there would be any cost differential between these
specific unique fittings

and others that the automotive industry could adopt instead. Thus, cost
impacts of this final rule on small entities are expected to be small.
This final rule is expected to relieve burden for some small entities,
such as car repair shops, by allowing them the flexibility to use a new
refrigerant that otherwise would have been prohibited under previous
requirements at appendix B to subpart G of 40 CFR part 82 and by
allowing them to use the easy-to-use ``quick-connect'' fittings for
this refrigerant. Other final rule requirements apply to original
equipment manufacturers, which are not small entities. These final rule
requirements are the least burdensome option for regulation.
    Original equipment manufacturers are not mandated to move to MVAC
systems using HFO-1234yf. EPA is simply listing HFO-1234yf as an
acceptable alternative with use conditions in new MVAC systems. This
rule allows the use of this alternative to ozone-depleting substances
in the MVAC sector and outlines the conditions necessary for safe use.
By approving this refrigerant under SNAP, EPA provides additional
choice to the automotive industry which, if adopted, would reduce the
impact of MVACs on the global environment. This rulemaking does not
mandate the use of HFO-1234yf as a refrigerant in new MVACs.

D. Unfunded Mandates Reform Act

    Title II of the Unfunded Mandates Reform Act of 1995 (UMRA), Public
Law 104-4, establishes requirements for Federal agencies to assess the
effects of their regulatory actions on State, local, and Tribal
governments and the private sector. Under section 202 of the UMRA, EPA
generally must prepare a written statement, including a cost-benefit
analysis, for proposed and final rules with ``Federal mandates'' that
may result in expenditures to State, local, and Tribal governments, in
the aggregate, or to the private sector, of $100 million or more in any
one year. Before promulgating an EPA rule for which a written statement
is needed, section 205 of the UMRA generally requires EPA to identify
and consider a reasonable number of regulatory alternatives and adopt
the least costly, most cost-effective or least burdensome alternative
that achieves the objectives of the rule. The provisions of section 205
do not apply when they are inconsistent with applicable law. Moreover,
section 205 allows EPA to adopt an alternative other than the least
costly, most cost-effective or least burdensome alternative if the
Administrator publishes with the final rule an explanation why that
alternative was not adopted. Before EPA establishes any regulatory
requirements that may significantly or uniquely affect small
governments, including Tribal governments, it must have developed under
section 203 of the UMRA a small government agency plan. The plan must
provide for notifying potentially affected small governments, enabling
officials of affected small governments to have meaningful and timely
input in the development of EPA regulatory proposals with significant
Federal intergovernmental mandates, and informing, educating, and
advising small governments on compliance with the regulatory
requirements.
    EPA has determined that this rule does not contain a Federal
mandate that may result in expenditures of $100 million or more for
State, local, and Tribal governments, in the aggregate, or the private
sector in any one year. Today's rule does not affect State, local, or
Tribal governments. The enforceable requirements of today's rule
related to system design and documentation of the safety of alternative
MVAC systems affect only a small number of original equipment
manufacturers. Further, those requirements are consistent with
requirements that the automotive industry has already adopted through
consensus standards of SAE International. We expect that most
manufacturers of automobiles and MVAC systems would attempt to meet
those requirements or something very similar, even in the absence of
EPA's regulations. The only requirement that is applied more widely
than for original equipment manufacturers is a requirement specifying
the type of unique service fittings required when servicing MVAC
systems using the refrigerant HFO-1234yf. Existing regulations at
appendix D to subpart G of 40 CFR part 82 already require that there be
unique service fittings for each refrigerant used in MVAC systems. The
fittings required in this final rule are part of the SAE J639 standard.
Thus, the costs of this rule are consistent with standard industry
practice and are expected to be much less than $100 million per year.
    This action provides additional options allowing greater
flexibility for industry in designing consumer products. The impact of
this rule on the private sector will be less than $100 million per
year. Thus, today's rule is not subject to the requirements of sections
202 and 205 of the UMRA. EPA has determined that this rule contains no
regulatory requirements that might significantly or uniquely affect
small governments. This regulation applies directly to facilities that
use these substances and not to governmental entities. This rule does
not mandate a switch to HFO-1234yf and the limited direct economic
impact on entities from this rulemaking is less than $100 million
annually.

E. Executive Order 13132: Federalism

    Executive Order 13132, entitled ``Federalism'' (64 FR 43255, August
10, 1999), requires EPA to develop an accountable process to ensure
``meaningful and timely input by State and local officials in the
development of regulatory policies that have federalism implications.''
``Policies that have federalism implications'' is defined in the
Executive Order to include regulations that 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.''
    This action does not have federalism implications. It will not have
substantial direct effects on the States, on the relationship between
the national government and the States, or on the distribution of power
and responsibilities among the various levels of government, as
specified in Executive Order 13132. This regulation applies directly to
facilities that use these substances and not to governmental entities.
Thus, Executive Order 13132 does not apply to this rule.

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

    Executive Order 13175, entitled ``Consultation and Coordination
with Indian Tribal Governments'' (59 FR 22951, November 6, 2000),
requires EPA to develop an accountable process to ensure ``meaningful
and timely input by tribal officials in the development of regulatory
policies that have tribal implications.'' This final rule does not have
Tribal implications, as specified in Executive Order 13175. 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,
Executive Order 13175 does not apply to this rule.

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

    This action is not subject to EO 13045 (62 FR 19885, April 23,
1997) because it is not economically significant as defined in EO
12866, and because the Agency does not 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 V
and VII.D of the preamble and in documents EPA-HQ-OAR-2008-0664-0036
and HQ-OAR-2008-0664-0038 in the docket for this rulemaking.

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

    This action 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 could impact manufacturing
and repair of MVAC systems using an alternative refrigerant. This rule
does not mandate a switch to HFO-1234yf. Preliminary information
indicates that these new systems are more energy efficient than
currently available systems in some climates. Therefore, we conclude
that this rule is not likely to have a significant adverse effect on
energy supply, distribution or use.
I. National Technology Transfer and Advancement Act
    Section 12(d) of the National Technology Transfer and Advancement
Act of 1995 (``NTTAA''), Public Law 104-113, 12(d) (15 U.S.C. 272 note)
directs EPA to use voluntary consensus standards in its regulatory
activities unless to do so would be inconsistent with applicable law or
otherwise impractical. Voluntary consensus standards are technical
standards (e.g., materials specifications, test methods, sampling
procedures, and business practices) that are developed or adopted by
voluntary consensus standards bodies. 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 decided to
use SAE International's most recent version of the SAE J1739 and SAE
J639 standards. These standards can be obtained from http://www.sae.org/technical/standards/. These standards address safety and
reliability issues in motor vehicle design, including MVAC systems
using alternative refrigerants.

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

    Executive Order (EO) 12898 (59 FR 7629 (Feb. 16, 1994)) establishes
Federal executive policy on environmental justice. Its main provision
directs Federal agencies, to the greatest extent practicable and
permitted by law, to make environmental justice part of their mission
by identifying and addressing, as appropriate, disproportionately high
and adverse human health or environmental effects of their programs,
policies, and activities on minority populations and low-income
populations in the United States.
    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. HFO-1234yf is a non-ozone-depleting substance with a
low GWP. Based on the toxicological and atmospheric work described
earlier, HFO-1234yf 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 car manufacturers
chose to make MVAC systems using this low GWP 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 the 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 May 31, 2011.

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-
2008-0664 at http://www.regulations.gov.

Benesch et al., 2002. Investigation of Effects of Trifluoroacetate
on Vernal Pool Ecosystems. Environ. Tox and Chem. Vol. 21, No. 3 pp.
640-647. 2002. Available online at http://www3.interscience.wiley.com/journal/122678081/abstract?CRETRY=1&SRETRY=0.
Benouali et al., 2008. ``A/C System Control Strategies for Major
Refrigerant Options'' June 11, 2008, Alternative Refrigerant Systems
Symposium Phoenix, AZ. Available online at http://www2.dupont.com/Refrigerants/en_US/assets/downloads/SmartAutoAC/2008_SAE_ARSS_Valeo_Eval.pdf.
Besnard, S., 1996. Full Flammability Test of Gases and Gas Mixtures
in Air. CERN. European Organization for Nuclear Research. 1996.
Available online at http://cdsweb.cern.ch/record/1217583/files/CM-P00055900.pdf.
Boutonnet et al., 1999. ``Environmental Risk Assessment of
Trifluoroacetic Acid,'' Human and Ecological Risk Assessment, Feb.
1999. Available online at http://www.informaworld.com/smpp/
content~db=all~content=a922749285~frm=abslink.
CARB, 2008. Technical Support Document ``Staff Analysis on Emissions
and Economic Impact of Proposed Regulation for Small Containers of
Automotive Refrigerant.'' Appendix G to Certification Procedures for
Small Containers of Automotive Refrigerant. California Air Resources
Board, effective March 10, 2010. Document incorporated by reference
in California Code of Regulations (CCR), title 17, sections 95360
through 95370. Available online at http://www.arb.ca.gov/regact/2009/hfc09/hfc09.htm.
Carter, 2009. Investigation of Atmospheric Ozone Impacts of 2,3,3,3-
Tetrafluoropropene. Final report to Honeywell International Contract
UCR-09010016. William Carter, University of California, Riverside
CA. June 2, 2009. Available online at http://www.cert.ucr.edu/%7Ecarter/pubs/YFrept.pdf.
Ceviz and Yuksel, 2005. ``Cyclic variations on LPG and gasoline-
fuelled lean burn SI engine.'' Renewable Energy. In press. Available
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genotoxicity tests to determine rodent carcinogens and non-
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List of Subjects in 40 CFR Part 82

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

    Dated: February 24, 2011.
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. Appendix B to Subpart G of Part 82 is amended as follows:
0
a. By adding one new entry to the end and by adding a note at the end
of the first table.
0
b. By revising the entry for ``CFC-12 Motor Vehicle Air Conditioners
(Retrofit and New Equipment/NIKs)'' in the table titled
``Refrigerants--Unacceptable Substitutes''.
    The additions and revisions 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 Automobile Motor Vehicle  HFO-1234yf as a    Acceptable         Manufacturers must      Additional
 Air Conditioning (New            substitute for     subject to use     adhere to all of the    training for
 equipment in passenger cars      CFC-12.            conditions.        safety requirements     service
 and light-duty trucks only).                                           listed in the Society   technicians
                                                                        of Automotive           recommended.
                                                                        Engineers (SAE)        Observe
                                                                        Standard J639           requirements of
                                                                        (adopted 2011),         Significant New
                                                                        including               Use Rule at 40
                                                                        requirements for:       CFR 721.10182.
                                                                        unique fittings,       HFO-1234yf is
                                                                        flammable refrigerant   also known as
                                                                        warning label, high-    2,3,3,3-
                                                                        pressure compressor     tetrafluoro-prop-
                                                                        cutoff switch and       1-ene (CAS No
                                                                        pressure relief         754-12-1).
                                                                        devices. For
                                                                        connections with
                                                                        refrigerant
                                                                        containers of 20 lbs
                                                                        or greater, use
                                                                        fittings consistent
                                                                        with SAE J2844.
                                                                       Manufacturers must
                                                                        conduct Failure Mode
                                                                        and Effect Analysis
                                                                        (FMEA) as provided in
                                                                        SAE J1739 (adopted
                                                                        2009). Manufacturers
                                                                        must keep the FMEA on
                                                                        file for at least
                                                                        three years from the
                                                                        date of creation.
----------------------------------------------------------------------------------------------------------------

* * * * *

    Note: The use conditions in this appendix contain references to
certain standards from SAE International. The standards are
incorporated by reference and the referenced sections are made part
of the regulations in part 82:
    1. SAE J639. Safety Standards for Motor Vehicle Refrigerant
Vapor Compression Systems. February 2011 edition. SAE International.
    2. SAE J1739. Potential Failure Mode and Effects Analysis in
Design (Design FMEA), Potential Failure Mode and Effects Analysis in
Manufacturing and Assembly Processes (Process FMEA). January 2009
edition. SAE International.
    3. SAE J2844. R-1234yf (HFO-1234yf) New Refrigerant Purity and
Container Requirements for Use in Mobile Air-Conditioning Systems.
February 2011 edition. SAE International.
    The Director of the Federal Register approves this incorporation
by reference in accordance with 5 U.S.C. 552(a) and 1 CFR part 51.
You may obtain a copy from SAE Customer Service, 400 Commonwealth
Drive, Warrendale, PA 15096-0001 USA; e-mail:
<EMAIL_ADDRESS>Telephone: 1-877-606-7323 (U.S. and Canada
only) or 1-724-776-4970 (outside the U.S. and Canada); Internet
address: http://store.sae.org/dlabout.htm.
    You may inspect a copy at U.S. EPA's Air Docket; EPA West
Building, Room 3334; 1301 Constitution Ave., NW.; Washington, DC or
at the National Archives and Records Administration (NARA). For
questions regarding access to these standards, the telephone number
of EPA's Air Docket is<PHONE_NUMBER>. For information on the
availability of this material at NARA, call<PHONE_NUMBER>, or go to:
http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_ locations.html.

* * * * *

                                     Refrigerants--Unacceptable Substitutes
----------------------------------------------------------------------------------------------------------------
              End-use                      Substitute               Decision                   Comments
----------------------------------------------------------------------------------------------------------------

                                                  * * * * * * *
CFC-12 Motor Vehicle Air             R-405A................  Unacceptable..........  R-405A contains R-c318, a
 Conditioners (Retrofit and New                                                       PFC, which has an
 Equipment/NIKs).                                                                     extremely high GWP and
                                                                                lifetime. Other
                                                                                Substitutes exist which do
                                                                                not contain PFCs.
                                    ----------------------------------------------------------------------------
                                     Hydrocarbon Blend B...  Unacceptable..........  Flammability is a serious
                                                                                concern. Data have not
                                                                                been submitted to
                                                                                demonstrate it can be used
                                                                                safely in this end-use.
                                    ----------------------------------------------------------------------------
                                     Flammable Substitutes,  Unacceptable..........  The risks associated with
                                      other than R-152a or                            using flammable
                                      HFO-1234yf in new                               substitutes (except R-152a
                                      equipment.                                      and HFO-1234yf) in this
                                                                                end-use have not been
                                                                                addressed by a risk
                                                                                assessment. R-152a and HFO-
                                                                                1234yf may be used in new
                                                                                equipment with the use
                                                                                conditions in appendix B
                                                                                to this subpart.
----------------------------------------------------------------------------------------------------------------

[FR Doc. 2011-6268 Filed 3-28-11; 8:45 am]
BILLING CODE 6560-50-P