identifying persons who cause violations of the prohibited acts in
today's proposal. We normally do not have the information necessary to
establish the cause of a violation found at a downstream facility. We
believe that those persons who actually handle the fuel are in the best
position to identify the cause of the violation, and that a rebuttable
presumption of liability would provide an incentive for parties to be
forthcoming with information regarding the cause of the violation. In
addition to identifying the party that caused the violation, providing
evidence to rebut a presumption of liability would serve to establish a
defense for the parties that are not responsible. Presumptive liability
is familiar to both the petroleum industry and EPA, and we believe that
this approach would make the most efficient use of EPA's enforcement
resources. For these reasons we are proposing a liability scheme based
on a presumption of liability. We request comment on the proposed
liability provisions.
c. Penalties for Violations
    CAA section 211(d)(1) provides for penalties for violations of the
fuels regulations. These penalty provisions subject any person that
violates any requirement or prohibition of the rule to a civil penalty
of up to $27,500 for every day of each such violation and the amount of
economic benefit or savings resulting from the violation. Pursuant to
40 CFR 19.4, the amounts of civil penalties for these violations
increased to $37,500 per day, plus the amount of any economic benefit
or savings resulting from the violation, for violations that occurred
after January 12, 2009. Today's proposal would subject any person who
violates any of the proposed requirements or prohibitions to a civil
penalty up to $37,500 for every day of each such violation and the
amount of the economic benefit or savings resulting from the violation.
    We propose that a violation of the requirements in today's notice
would constitute a separate day of violation for each day the gasoline
giving rise to the violation remains in the fuel's distribution system.
The length of time the gasoline in question remains in the distribution
system would be deemed to be twenty-five days unless there is evidence
that the fuel remained in its distribution system a lesser or greater
amount of time. These proposed penalty provisions are similar to those
in the RFG, Tier 2 sulfur, and diesel sulfur programs. We request
comment on the proposed penalty provisions.

IV. Other Measures To Ensure Compliance

A. The 1.0 psi RVP Waiver for E10 Blends

    One concern that was raised in the comment periods on the E15
waiver and RFS2 NPRM in addition to stakeholder meetings prior to this
proposal was whether E15 would qualify for the 1.0 psi RVP waiver
permitted under the Clean Air Act (CAA) section 211(h) for conventional
gasoline. As discussed in the partial waiver decision document, we
believe that E15 blends with higher volatility would cause vehicles to
violate their evaporative emission standards in-use. Consequently, the
waiver announced today is for E15 blends that meet the summertime
gasoline volatility standards for conventional gasoline without any 1.0
psi RVP waiver, and the regulatory provisions proposed today reflect
this decision. Furthermore, EPA interprets section 211(h)(4) of the CAA
as limiting the 1.0 psi waiver to gasoline-ethanol blends that contain
10 vol% ethanol, including limiting the provision concerning ``deemed
to be in full compliance'' to the same 10 vol% blends. EPA implemented
CAA section 211(h)(4) through 40 CFR 80.27(d) which provides that
gasoline-ethanol blends that contain at least 9 vol% ethanol and not
more than 10 vol% ethanol qualify for the 1.0 psi waiver of the
applicable RVP standard. Nevertheless, we seek comment on whether
section 211(h) of the CAA could be interpreted such that E15 is
eligible for the RVP provisions in section 211(h)(4) and whether this
would have any impact on our E15 waiver decision.
    In order to introduce a fuel that meets both the Federal summertime
RVP standards and contains between 10 and 15 vol% ethanol, fuel
refiners would have to create a fuel or blendstock that has
approximately 1.0 psi lower RVP than a fuel or blendstock intended for
E10 due to the interaction between gasoline volatility and ethanol when
blended. Oxygenate blenders would need to know the RVP of a blendstock
or have the intended ethanol content of a blendstock be specified on
the PTD to ensure that they know the correct amount of ethanol that
should be blended into a fuel. If an oxygenate blender or retail
station blended more than 10 vol% ethanol into a fuel or blendstock
produced with the expectation of taking advantage of the 1 psi waiver
that applies to E10, the resulting blend would be in violation of
summertime RVP standards.
    Having E10 and E15 at different RVP levels in-use also raises the
potential that mixtures of the two at retail would cause the blend to
exceed the summertime RVP requirements. Many retail stations only have
two underground storage tanks and those tanks typically contain regular
and premium grade fuels. Since, in many cases, midgrade gasoline is
made by blending regular and premium grade gasoline, the possibility
exists that a midgrade fuel blended from a high-RVP E10 fuel and a low-
RVP E15 fuel would exceed summertime RVP requirements. This fuel would
not receive the 1.0 psi RVP waiver and selling such a fuel would
violate RVP requirements.
    These RVP related complications could be avoided by refiners
producing a lower RVP blendstock for E10 as well. While there are cost
and supply considerations refiners and fuel distributors may find it in
their best interest to do so given the flexibility it affords.
Regardless, the Agency believes that it would be possible to help
alleviate some of these challenges with the slight modifications to the
PTDs and the national fuel survey requirements discussed in Section III
of this proposal. RFG already has similar requirements to those that we
are proposing in today's rulemaking, and given the effectiveness we
have had with the RFG program, we believe that the proposed approach
would be an effective means of allowing fuel manufacturers to ensure
that the correct amount of ethanol was blended into the appropriate
blendstock or finished fuel with only slight additions at minimal
costs. We believe that these PTD proposals are appropriate under our
authority under sections 208 and 114 of the Clean Air Act.
1. National RVP Survey
    In section III.C., we described our proposal for a national E15
labeling and ethanol content survey that is intended to ensure that
fuel pumps would be properly labeled if retail stations chose to sell
E15. In order to determine if the proposed labeling requirements are
being met and the ethanol content is consistent with the label, fuel
sampling and testing would be required to determine the ethanol
content. Since fuel refiners will have difficulty ensuring that
downstream summertime RVP requirements are met in non-RFG areas, adding
testing for RVP to this survey would be a low-cost \43\ approach to
enforcing downstream RVP standards and help provide an affirmative
defense for upstream parties in the event of a violation downstream. We
seek comment on whether RVP survey requirements should be included as
part of the national ethanol survey proposed in section III.C.
---------------------------------------------------------------------------

    \43\ Based EPA discussions with industry, the costs of for RVP
survey requirements as part of the E15 labeling survey would add
approximately $200,000 dollars per year to the total costs of the
survey.
---------------------------------------------------------------------------

2. RVP and E15 Underground Storage Tank Transition
    Another issue associated with the RVP standards is the potential
comingling of a higher RVP E10 fuel that received the 1.0 psi RVP
waiver with a lower RVP E15 that met summertime RVP requirements in
underground storage tanks when a retail station decides to transition
from selling E10 to E15. If the retail station does not completely
remove all E10 from a tank before E15 is added to the tank, the retail
station would create a fuel that violates RVP standards. The resulting
blend would be above 10 vol% ethanol and would not qualify for the 1.0
psi waiver, but would have an RVP above the requirement for E0 and E15.
    Section 211(t) of the Clean Air Act, as amended by the Energy
Policy Act of 2005, allows retail stations to blend compliant RFG
batches of non-ethanol blended and ethanol-blended gasoline in storage
tanks twice a year as long as the duration of the blended period is no
longer than 10 consecutive calendar days. However, the authority
granted to the Agency for the transition of fuels in underground
storage tanks was specifically limited to that case and we do not
believe this provision authorizes a blending down of E10 and E15 over
time in non-RFG areas.
    We seek comment on the issue of tank transition from E10 to E15
fuels and if there are ways that the Agency could address this issue.

B. Credit for RFG Downstream Oxygenate Blending

    Pursuant to 40 CFR 80.69, refiners of RBOB are permitted to take
credit for downstream oxygenate blending toward compliance with RFG
standards. To do so the refiner must direct the downstream oxygenate
blender on the PTD to add a particular type and amount of oxygenate.
However, these provisions may require some reconsideration. In light of
the addition of E15 to the RFG marketplace, it may be more difficult to
ensure that 15 vol% ethanol is in fact added downstream if the RBOB
would also meet all other finished gasoline specifications with the
addition of just 10 vol% ethanol. Oxygenate blenders could also be left
in the untenable position of having a supply of RBOB for E15 blending
and an inability to blend more than 10 vol%

ethanol. We request comment regarding how the final regulation should
address this issue. For example, the regulation could limit the
refiner's claimed ethanol content to 10 vol% ethanol unless: (A) The
final blend would not comply with all gasoline specifications (e.g.,
octane) without the addition of 15 vol% ethanol, or (B) until such time
as the RBOB surveys for a particular RFG area indicates that there is a
sufficient, stable market demand for E15. We request comment on this
and other approaches to resolve this issue.

V. Modification of the Complex Model

A. Background of RFG Requirements

    Reformulated gasoline (RFG) is gasoline that is required to be sold
in certain parts of the country, and is required to be reformulated to
meet certain performance standards for emissions of smog forming and
toxic air pollutants. In 1990 Congress amended the CAA to require that
RFG be sold in cities with the worst ozone pollution problems. In
addition, other cities with significant smog problems were provided the
opportunity to voluntarily opt-in to the RFG program. RFG is currently
used in portions of 17 States and the District of Columbia. About 30%
of gasoline sold in the U.S. is reformulated. In the 1990 Amendments,
Congress also required that conventional gasoline (CG, or non-RFG) sold
in the rest of the country become no more polluting than gasoline sold
in 1990. Often referred to as ``anti-dumping'', this requirement
ensures that refiners do not ``dump'' into conventional gasoline fuel
components that are restricted in RFG and that increase environmentally
harmful emissions.
    EPA introduced the RFG program in 1995, as required by the CAA. The
RFG program established emissions performance standards for volatile
organic compounds (VOCs), nitrogen oxides (NOX), and toxics.
These standards are based on percent reductions from the average
emissions of these pollutants in 1990 model year vehicles operated on a
specified baseline gasoline. The program required an oxygen minimum
standard of 2.0% by weight, however the Energy Policy Act of 2005
removed that requirement. For conventional gasoline, the program
establishes emissions standards for exhaust toxics and NOX
designed to ensure that an individual refinery's or importer's gasoline
will not have higher levels of these pollutants than the refinery's or
importer's 1990 gasoline.
    Refiners of RFG must comply with the RFG standards separately for
each refinery. Refiners of conventional gasoline may comply separately
for each refinery, or they may aggregate their refineries. Importers
comply with both the RFG and conventional gasoline standards for the
aggregate of the gasoline they import during the year.

B. The Complex Model

    To measure compliance with the RFG and anti-dumping standards, the
emissions performance of gasoline is calculated using a model, called
the Complex Model, which predicts the emissions level of each regulated
pollutant based on the measured values of certain gasoline properties.
These properties are: Aromatics, olefins, sulfur, Reid Vapor Pressure
(RVP), benzene, oxygen and distillation points, as well as the content
of ethanol, ETBE, TAME and MTBE. Refiners and importers are required to
measure these properties in each batch of gasoline they produce or
import, using a prescribed test method, and calculate the emissions
level of each pollutant for each batch of gasoline using the Complex
Model. The emissions level as computed by the Complex Model is compared
to the baseline emissions for each pollutant, and the percent reduction
is then calculated. The standards for VOC, NOX and toxics
are stated in terms of percent reductions from the baseline. Thus, for
fuel to comply with the standards, the percent reduction computed by
the Complex Model must be equal to or greater than the standard for
each pollutant. Under the Clean Air Act, baseline emissions must be
based on 1990 vehicle technology, not current fleets, nor off-road
equipment.
    For gasoline to be sold in the U.S., it must comply with the
standards. Refiners are therefore required to certify that their fuel
meets the standards by using the Complex Model. Currently, the
equations in the model are limited to an oxygen content of no more than
4.0% by weight in gasoline, which is the maximum amount of oxygen in
gasoline containing 10 vol% ethanol, or E10.\44\ In order for refiners
to produce gasoline that will contain 15 vol% ethanol, the model must
be modified to predict the effect of the additional oxygen.
---------------------------------------------------------------------------

    \44\ Because the percent by weight of oxygen in the fuel varies
depending on the density of the fuel, the limit in the Complex Model
is currently 4.0% by weight to reflect the maximum amount of oxygen
associated with E10. In most fuels, however, this volume is
equivalent to 3.5% by weight oxygen.
---------------------------------------------------------------------------

    The applicability of the Complex Model to gasoline certification
has become limited as EPA's more recent clean gasoline standards take
effect and provide even greater emission reductions beyond those of the
RFG program. The NOX emission performance requirements for
RFG and conventional gasoline have not been required since January 1,
2007 when the Tier2 gasoline average sulfur standard of 30 ppm took
effect (see 40 CFR 80.101(c)(3)(i)). Finally, beginning January 1,
2011, the air toxics emission standards for gasoline will be deemed met
by compliance with the new MSAT2 nationwide benzene standard for
gasoline, the volatility standard, and sulfur standard (see 40 CFR
80.41(e)(2) and (3)). The result is that beginning January 1, 2011,
only the VOC equation in the Complex Model will continue to be binding
and only for RFG. For conventional gasoline, there are no VOC
performance standards; only RVP limits. Thus, compliance with the anti-
dumping regulations does not require use of the Complex Model to
evaluate VOC emissions.
    The one exception to this is small refiners that take advantage of
the option for delayed compliance with the MSAT2 benzene standard until
January 1, 2015. They would still need the Complex Model for air toxics
emission performance compliance during this interim period. However,
since no small refiners are currently producing RFG, it would only be
for CG. For CG, since refiners typically certify CG as E0, with
oxygenate blended downstream, they should be unaffected by the increase
in ethanol content from E10 to E15. Therefore, it appears that the only
equation that needs to be modified in the Complex Model to allow
refiners and importers to certify gasoline containing E15 after January
1, 2011 is the VOC equation.
    Because emissions performance at issue is specified in the Act as
the emissions performance of 1990 vehicle technology, we are not able
to use current emission test data on motor vehicles using E15 gasoline
as a basis for evaluating appropriate changes to the VOC equation. The
test results from today's vehicle fleet would not represent the 1990
vehicle technology required to calculate the emission baseline.
Instead, we relied on a study conducted in 1994 by Guerrieri, et al.,
that examined the exhaust emissions from 1990 vehicles using gasoline
with ethanol levels varying from 0 to 40 volume percent.\45\ Figure
V.B-1 shows data reported by Guerrieri et al.\46\ The figure shows the
average values of

hydrocarbon emissions (representative of VOC) at several ethanol levels
relevant to this discussion, as well as the uncertainty bars at each
value. The study data showed that on average exhaust hydrocarbon
emissions increased from E10 to E12, but then decreased beyond E12.
While the study does not provide sufficient data to determine the
precise VOC emission effect between E10 and E15, the linear regression
results presented in the study (also shown in Figure V.B-1) indicate a
decreasing trend in hydrocarbon emissions with increased ethanol in
gasoline. Based on the study findings, we are reasonably confident that
the average VOC emissions for ethanol blends greater than E10 up to and
including E15 will be no worse than for E10, for 1990 technology motor
vehicles. This outcome is consistent with our engineering judgment. As
discussed in Section VI.C the general trend across vehicles of all ages
is that the addition of ethanol to gasoline tends to lower VOC
emissions due to its enleanment effect during open loop operation.

    \45\ Guerrieri, David Al., Peter Caffrey, and Venkatesch Rao;
Investigation Into the Vehicle Exhaust Emissions of High Percentage
Ethanol Blends''; SAE Technical Paper Series; 950777; presented at
International Congress and Exposition; Detroit, Michigan; March,
1995.
    \46\ Guerrieri, et al.; op. cit.
    [GRAPHIC] [TIFF OMITTED] TP04NO10.001

    Because the data available on 1990 vehicles is limited, we are not
proposing to change the Complex Model to indicate decreasing VOC
emissions with increased ethanol content between E10 and E15. Instead,
we are proposing to modify the application of the Complex Model
equations to treat VOC exhaust emissions at ethanol levels greater than
E10 and up to E15 the same as for E10. We are therefore proposing in
today's rule to modify the Complex Model to allow up oxygen levels up
to 5.8% by weight to be input to the model but that the VOC emissions
effects would be modeled the same as if it contained 4.0% by weight
oxygen.\47\ This will provide flexibility for the Complex Model to be
used over a broader range of ethanol content. We request comment on
whether the data and rationale discussed above are an appropriate basis
for the proposed adjustment to the Complex Model to account for E15.
---------------------------------------------------------------------------

    \47\ The level of 5.8% by weight of oxygen is the potential
maximum oxygen level associated with E15 due to lighter than average
gasoline components. The typical weight of oxygen in E15 is 5.2%.
---------------------------------------------------------------------------

VI. Why are we proposing misfueling mitigation measures?

    In previous sections we proposed to prohibit the use of E15 in
MY2000 and older motor vehicles, heavy-duty gasoline engines and
vehicles, motorcycles, and all nonroad products (which includes marine
applications). This section provides the technical rationale supporting
this decision. As discussed below, it appears that the unique physical
and chemical properties of ethanol may impact these products when they
are using gasoline-ethanol blends, particularly as many of these
products were not designed to operate on such fuels. The potential
impacts could be the impairment of the performance of their emission
control devices or systems, which would likely lead to increased HC, CO
and/or NOX emissions.
    Light-duty motor vehicles (i.e., passenger cars and light-duty
trucks) have evolved significantly over time, mainly in response to
increasingly tighter emission standards, but also to improve fuel
economy, vehicle driveability, and vehicle durability. The primary
advancements in emissions control have been in the control of the air-
to-fuel (A/F) ratio matched with advancements in catalyst formulations
and designs with each new generation of motor vehicles. Today's motor
vehicles are far more sophisticated and up to 99% less polluting than
they were in the 1970s while also more tolerant of variables like fuel
composition (i.e., RVP, oxygen content). However, MY2000 and older
light-duty motor vehicles have not benefitted from these

advancements in technology and could experience combustion and material
compatibility problems leading to increased emissions if operated on
E15. While motorcycles (highway and off-highway), heavy-duty gasoline
engines and vehicles, and nonroad products have also evolved over time,
since they have not been regulated as long, and have much more diverse
applications, they do not reflect the same level of advanced technology
across the board as do today's light-duty motor vehicles. Consequently,
their engines and emission control systems may also be impacted in ways
that affect emission performance if operated on E15.
    On the other hand, the Agency believes that newer light-duty motor
vehicles (vehicles designed to meet Tier 2 emissions standards) were
designed with significantly more robust emission controls and fuel
system components to regularly use gasoline-ethanol blends. For MY2001-
2006 light-duty motor vehicles, EPA does not have enough data on which
to base a decision at this point in time. DOE testing of MY2001-2006
light-duty motor vehicles is ongoing and will factor into the Agency's
decisions for the final rule.
    The sections that follow discuss in more detail the history of
ethanol use in the U.S., the chemical and physical differences between
ethanol and gasoline, and how these differences, especially combustion
enleanment and material compatibility, could impact exhaust and
evaporative components and emissions. Specifically, we discuss the
ability of the following groups of vehicles and engines to handle E15:
(1) MY2000 and older light-duty motor vehicles; (2) heavy-duty gasoline
engines and vehicles; (3) motorcycles; (4) nonroad products; (5) MY2007
and newer light-duty motor vehicles; and (6) MY2001-2006 light-duty
motor vehicles.

A. History of Ethanol Use in the U.S.

    Any assessment of the impacts of E15 use in vehicles, engines, and
equipment must begin with an understanding of the degree to which they
were designed for the use of low level gasoline-ethanol blends. E10 is
currently blended in significant quantities in most gasoline
distributed and sold in most States, but this was not always the case.
Most auto manufacturers today support the use of E10 in their vehicles
and engines since their designs have evolved over time in response to
the growing use of E10 across the country. However, the total fleet is
made up of old and new vehicles, engines, and equipment with varying
technologies and therefore varying compatibility with gasoline-ethanol
blends.
    Ethanol and ethanol-gasoline blends have a long history as
automotive fuels in the United States. Inexpensive crude oil prices
kept ethanol from making a significant presence in the transportation
sector until the end of the 20th century when tax subsidies and
environmental programs helped to spur growth. On November 9, 1978, the
U.S. passed the Energy Tax Act which defined ``gasohol'' as a blend of
gasoline with 10% alcohol by volume (excluding alcohol made from
petroleum, natural gas or coal) and offered the fuel an excise tax
exemption to encourage its use.\48\ While the ethanol tax subsidy has
been modified over the years, conventional ethanol continues to receive
a $0.45/gallon tax credit and cellulosic ethanol is eligible for a
$1.01/gallon credit.
---------------------------------------------------------------------------

    \48\ Refer to the Energy Tax Act of 1978, Public Law 95-618,
enacted November 9, 1978.
---------------------------------------------------------------------------

    Environmental programs have also been an important contributor to
ethanol expansion in the United States. First, in the late 1980s and
early 1990s, ethanol was used as a gasoline oxygenate (along with MTBE)
to help reduce carbon monoxide (CO) emissions in various CO
nonattainment areas. Then, ethanol was used as part of the requirements
for reformulated gasoline in the worst ozone nonattainment areas
beginning in the mid 1990s.
    Tax subsidies and environmental programs resulted in the growth of
the fuel ethanol market such that by the late 1990s, E10 represented
slightly more than 10% of gasoline nationwide. By 1999, 35 States were
blending ethanol into at least a portion of their gasoline.\49\
However, its use remained concentrated in the Midwest, e.g., Illinois,
Ohio, and Minnesota. Ethanol did not begin expanding significantly
beyond the Midwest until the early 2000s when States started banning
the use of Methyl Tertiary-butyl Ether (MTBE) due to groundwater
concerns. Ethanol quickly became the primary oxygenate in the gasoline
market. With the removal of the RFG oxygen mandate by the Energy Policy
Act of 2005 (EPAct), MTBE was removed from gasoline almost entirely by
2006. Ethanol replaced MTBE, broadening the fuel's use into California,
the East Coast, and other RFG areas. From 2000 to 2006, the share of
gasoline containing 10% ethanol by volume (``E10 market share'') more
than doubled as shown in Figure VI.A.-1. According to fuel survey and
certification data, ethanol is the only oxygenate currently used in any
significant quantity today.
---------------------------------------------------------------------------

    \49\ EIA, Motor Gasoline Outlook and State MTBE Bans, Table 2,
available at: http://www.eia.doe.gov/emeu/steo/pub/special/
mtbeban.html and FHWA, Estimate Use of Gasohol, 1999, available at:
http://www.fhwa.dot.gov/ohim/hs99/tables/mf33e.pdf.

---------------------------------------------------------------------------

[GRAPHIC] [TIFF OMITTED] TP04NO10.002

    Since 2006, E10's market share has continued to rise. The increase
can be attributed primarily to rising crude oil prices which led to
very favorable ethanol blending economics over most of the past 4-5
years, but also to the market certainty provided by the Renewable Fuel
Standard (RFS) established by EPAct and later modified by the Energy
Independence and Security Act of 2007 (EISA). EPAct required 7.5
billion gallons of renewable fuel to be blended into transportation
fuel by 2012. In 2007, EISA expanded the RFS to 36 billion gallons by
2022. On March 26, 2010, EPA promulgated final RFS2 regulations to
implement the EISA volumes.\50\ While there are a number of renewable
fuels that can be used to meet the RFS2 requirements, EPA projects a
large percentage will come from ethanol. According to EIA, ethanol
comprised 9.4% of total U.S. motor gasoline sales during the first half
of 2010.\51\ In other words, over 90% of motor gasoline sold today is
E10.
---------------------------------------------------------------------------

    \50\ 75 FR 14670 (March 26, 2010).
    \51\ Refer to EIA Monthly Energy Review September 2010 (Tables
10.3 and 3.7c, respectively).
---------------------------------------------------------------------------

    As E10's market share has increased over the last few years, its
prevalence has also expanded nationwide. A map showing today's
estimated E10 penetration by State is provided in Figure VI.A-2. This
State-level information, provided by HART Energy Consulting, does not
reflect California's recent shift from 5.7 to 10 vol% ethanol. While
vehicles, engines, and equipment in the Midwest have been experiencing
E10 use for a number of years, this is not the case in most of the
country. Even in much of the Midwest, E10 has become the dominant fuel
only recently. It took many years for States to reach 25% E10
saturation and even longer for States to reach 50% E10 saturation. As
shown in Figure VI.A-3, 23 States (including the District of Columbia)
just recently reached 50% saturation between 2008 and 2009.\52\ Alaska
is the only State without significant ethanol blending. According to
HART, only 10% of Alaska's gasoline is currently comprised of E10.
---------------------------------------------------------------------------

    \52\ 1999-2004 state E10 marketshares based on FHWA ethanol and
EIA total motor gasoline sales. 2005 ethanol usage based on EIA's
National Emission Inventory Estimates. 2007-2009 based on HART
estimates.

---------------------------------------------------------------------------

[GRAPHIC] [TIFF OMITTED] TP04NO10.003

[GRAPHIC] [TIFF OMITTED] TP04NO10.004

B. Chemical and Physical Differences Between Ethanol and Gasoline

    Understanding the chemical and physical differences between
gasoline and ethanol is helpful in determining how increased ethanol
concentrations in gasoline may impact vehicle and engine technologies
and whether emission differences may occur. Throughout most of the 20th
century, engines and vehicles were designed to run on gasoline. Engines
can and have been designed for the use of ethanol, and in the case of
FFVs, have been designed to operate effectively on both.\53\ Over the
last couple of decades, manufacturers have also taken varying steps to
redesign their gasoline engines to be more compatible with blends of
gasoline and ethanol up to 10 vol%.
---------------------------------------------------------------------------

    \53\ In the U.S., the most common FFVs are also known as ``E85''
vehicles. They are designed to run on gasoline or a blend of up to
85 vol% ethanol (E85) and are equipped with modified components
designed specifically to be compatible with ethanol's chemical
properties.
---------------------------------------------------------------------------

    Gasoline is a complex mixture of several hundred hydrocarbon
molecules (organic compounds containing carbon and hydrogen) ranging in
carbon number from four to twelve that are produced from various
refinery streams. In contrast, fuel ethanol contains only one kind of
molecule with two carbon atoms. Alcohols such as ethanol are derived
from hydrocarbons by replacing the hydrogen atoms in their parent
hydrocarbon (ethane is the parent of ethanol) with one or more hydroxyl
groups containing oxygen and hydrogen.
    Gasoline quality specifications are provided by ASTM D4814,\54\
while ethanol quality specifications for blending in gasoline are
provided by ASTM D4806.\55\ Several properties of ethanol, as compared
to typical gasoline and toluene, are listed below in Table VI.B-1.
Since toluene is a common hydrocarbon used as an octane enhancer in
gasoline, it is included below for comparison purposes.\56\ Ethanol has
been used successfully in gasoline for several decades as a volumetric
fuel extender due to its beneficial Research Octane Number and Motor
Octane Number blending values.
---------------------------------------------------------------------------

    \54\ ASTM D4814, Standard Specification for Automotive Spark
Ignition Fuel.
    \55\ ASTM D4806, Standard Specification for Denatured Fuel
Ethanol for Blending with Gasoline for Use in Automotive Spark
Ignition Fuel.
    \56\ SAE J1297, revised July, 2007, Surface Vehicle Information
Report, Alternative Fuels.

                       Table VI.B-1--Properties of Ethanol, Gasoline and Toluene 57 58 59
----------------------------------------------------------------------------------------------------------------
                                         Gasoline (typical
              Property                      properties)                 Toluene                  Ethanol
----------------------------------------------------------------------------------------------------------------
Chemical Formula....................  Mixed C4 to C12          C7H8....................  CH3CH2OH.
                                       Hydrocarbons.
Molecular Weight....................  95-115.................  92......................  46.
Oxygen Weight Percent...............  .......................  0.......................  34.7.
Boiling Point [deg]F................  85-437.................  231.....................  173.
Specific Gravity 60 [deg]F/60 [deg]F  0.72-0.78..............  0.87....................  0.79.
Research Octane Number..............  91-100.................  111.....................  111.
Motor Octane Number.................  82-92..................  95......................  92.
(R + M)/2...........................  87-92..................  103.....................  102.
Net Heat of Combustion BTU/Gal \60\.  117,000................  126,000.................  76,000.
Latent Heat of Vaporization BTU/Gal   800....................  1130....................  2600.
 \61\.
Solubility in Water, gram/100g H2O..  Trace..................  Trace...................  Infinite.
Stoichiometric A/F Ratio, Mass Air/   14.6...................  13.5....................  9.0.
 Mass Fuel.
Vapor Flammability Limits Percent by  0.6-8..................  ........................  3.5-15.
 Volume.
Vapor Pressure @ 100 [deg]F psi.....  9-13...................  ........................  2.5.
----------------------------------------------------------------------------------------------------------------

    Because gasoline is composed of different molecules of different
lengths, it has a boiling range as well as a distillation curve. On the
other hand, because ethanol is composed of a single type of molecule,
it has a single boiling point and lacks the characteristic distillation
curve of gasoline. Functional groups such as ethanol's hydroxyl group
generally determine how a molecule will behave.
---------------------------------------------------------------------------

    \57\ SAE J1297, revised July, 2007, Surface Vehicle Information
Report, Alternative Fuels. Note: The values in Table 1 should be
considered for relative comparisons only.
    \58\ SAE 861178, ``The Properties and Performance of Modern
Automotive Fuels,'' P. Dorn, A.M. Mourao, and S. Herbstman, Texaco
Research Center, Beacon, N.Y.
    \59\ SAE 912413 ``An Overview of the Technical Implications of
Methanol and Ethanol as Highway Motor Vehicle Fuels,'' Frank Black,
U.S. Environmental Protection Agency, Research Triangle Park, N.C.
    \60\ BTU/Gal = 279 J/L
    \61\ BTU/Gal = 279 J/L
---------------------------------------------------------------------------

    The question with the use of E15 is whether or not the vehicles,
engines, equipment, and products that are designed for the properties
of gasoline and/or E10 are also designed for the properties of E15.
Some property differences between E10 and E15 may be dealt with in fuel
blending such that the base gasoline can be adjusted in advance to
accommodate the ethanol. This adjustment will ensure that the resulting
blend meets a target specification for properties such as volatility
and octane rating. On the other hand, some property differences between
E10 and E15 are inherent to the ethanol fraction and cannot be
accounted for by blending. For example, the impact of E15 versus E10 on
engine combustion is a potential concern. How a vehicle or engine
adapts to combust fuels with different ethanol concentrations depends
on the vehicle hardware and software control strategies. Vehicles and
engines operating on E15 may have hotter exhaust temperatures than the
same vehicles and engines running on E10. In addition, material
compatibility is time, temperature, and concentration dependent. Some
material effects with E15 are possible that may not have been
experienced with E10 in the past.
    The following sections describe in greater detail the chemical and
physical differences of gasoline and ethanol, particularly focusing on
the effects of these differences when ethanol is blended with gasoline.
This discussion lays the foundation for vehicle and engine specific
discussion in sections VI.C.-VI.I.
1. Impact on the A/F Ratio--Combustion Enleanment
    When gasoline is combusted in an engine, the stoichiometric A/F
ratio (i.e., the ideal ratio for complete combustion of the fuel and
air into carbon dioxide and water vapor) is approximately 14.7 times
the mass of air to fuel (14.7:1). For gasoline, any mixture less than
14.7:1 is

considered to be a rich mixture (excess fuel), and any mixture more
than 14.7:1 is a lean mixture (excess air/oxygen) given ideal test fuel
and complete combustion. The addition of oxygenates such as ethanol
(with its hydroxyl group) to gasoline alters the stoichiometric A/F
ratio and therefore affects combustion. Engines/vehicles equipped with
feedback controls can adjust the A/F ratio to stoichiometric
conditions--around 14.0:1 for E10 and 13.8:1 for E15 (the ratio is
lower as ethanol contains oxygen so less air is needed). However, for
gasoline engines that do not have the ability to react to the desired
stoichiometric A/F ratio for a different fuel (e.g., gasoline-ethanol
blends), combustion is enleaned. E10 would result in approximately 4%
enleanment when compared with gasoline, E15 would result in
approximately 6% enleanment. This means E10 and E15 have 4% and 6% more
oxygen, respectively, than the stoichiometric A/F ratio.
    Fuel metering components are sized to deliver an A/F mixture that
optimizes emission performance, power output, fuel economy, and
durability. If an engine is allowed to operate at a mixture that is
leaner than it is designed for (too much oxygen for a given amount of
fuel), it may run at a somewhat higher combustion temperature. This in
turn can lead to changes in exhaust temperatures which may affect
catalyst durability, and, especially in the case of nonroad products,
engine durability, causing an increase in emissions. In addition,
combustion instability from lean mixtures, which can cause misfire, can
then lead to accelerated catalyst performance degradation or damage.
2. Polarity and Affinity for Water
    Water is one of the most polar molecules (an uneven distribution of
charge with the hydrogen atoms being positively charged and the oxygen
atom negatively charged) while ethanol is only slightly polar and a
hydrophilic (meaning water loving) molecule because of its hydroxyl
group. Ethanol dissolves in water when the two are mixed together.
Unlike ethanol, gasoline is considered to be a non-polar and
hydrophobic hydrocarbon molecule which means that it does not attract
water in the same way as ethanol does. As a result, gasoline and water
are only very slightly soluble. If enough water is added to straight
gasoline, two layers will form, known as phase separation: a water
layer and a gasoline layer.
    Ethanol is soluble in gasoline though to a lesser extent than it is
in water. If a gasoline-ethanol blend is saturated with water, a
reduction in ambient temperature may cause the ethanol and gasoline to
separate into two layers. However, the presence of ethanol in gasoline
will allow more water to be absorbed by the gasoline-ethanol blend
before phase separation occurs. Some level of water carried through the
fuel distribution system is generally acceptable and likely unavoidable
given fuel exposure to moisture and humidity in normal dispensing and
storage, either at the fuel station or on-board. However, excessive
water in the fuel can lead to phase separation that can in turn cause
stalling or permanent damage to most internal combustion engines.
3. Material Compatibility
    The hydroxyl group of ethanol also reacts with natural rubber
materials. Certain elastomers exposed to alcohols may swell or soften
and lose strength.\62\ Some plastics and fiberglass can become brittle
leading to cracks and leaks.\63\ Table VI.B.2.-1 shows the effects of
gasoline and ethanol on some of the many elastomers that have been
developed.\64\ As noted from this table, polyfluorocarbons have been
shown to be compatible with ethanol and ethanol blends. As discussed
below in VI.C.2., the physical interaction of ethanol with certain
elastomers also leads to increased permeation of ethanol and
hydrocarbons through the walls of components made from such materials.
---------------------------------------------------------------------------

    \62\ SAE 912413 ``An Overview of the Technical Implications of
Methanol and Ethanol as Highway Motor Vehicle Fuels,'' Frank Black,
U.S. Environmental Protection Agency, Research Triangle Park, N.C.
    \63\ SAE 912413 ``An Overview of the Technical Implications of
Methanol and Ethanol as Highway Motor Vehicle Fuels,'' Frank Black,
U.S. Environmental Protection Agency, Research Triangle Park, N.C.
    \64\ Discussion of additional studies evaluating the impacts of
gasoline-ethanol blends on materials used in vehicles and nonroad
engines, vehicles, and equipment can be found in the subsections
that follow.

      Table VI.B.2-1--Effects of Gasoline and Ethanol on Elastomers
------------------------------------------------------------------------
                                       Volume swell (%) after 72 hour
                                               immersion in:
            Elastomer             --------------------------------------
                                     Gasoline     Ethanol        E10
------------------------------------------------------------------------
Fluorocarbon (FKM)...............            0            2            3
Polyester urethane...............           11           19           37
Fluorosilicone (FMQ).............           14            6           18
Butadiene-acrylonitrile (NBR)....           43            8           51
Polyacrylate (ACM)...............           44          101          136
Chlorosulfonated polyethylene               49            1           56
 (CSM)...........................
Ethylene-propylenediene                    137           13          124
 terpolymer (ePDM)...............
Natural Rubber (NR)..............          169            2          176
------------------------------------------------------------------------
Adapted from SAE 912413 ``An Overview of the Technical Implications of
  Methanol and Ethanol as Highway Motor Vehicle Fuels,'' Frank Black,
  U.S. Environmental Protection Agency, Research Triangle Park, N.C.

4. Corrosion
    Ethanol can also contribute to corrosion due to galvanic coupling
or the absorption of water. Alcohols are better electrical conductors
compared to gasoline so gasoline-ethanol blends could promote galvanic
corrosion and galvanic-couple effects between electrochemically
dissimilar alloys in the fuel system.65, 66 The National
Ethanol Vehicle Coalition and the Petroleum Equipment Institute have
demonstrated that aluminum is sensitive to corrosion from ethanol. In
addition, water in gasoline-ethanol blends can cause corrosion of
metallic materials (such as brass, cast iron, copper, and various types
of steel) as the

water/ethanol layer becomes acidic if phase separation occurs.\67\ The
presence of water in the fuel distribution system also provides a
suitable habitat for the growth of microbes which excrete acids that in
turn are also detrimental to metallic fuel storage systems.\68\
Contaminants in water may also impact additives used in finished fuel
that are designed to maintain the integrity of the finished
fuel.69, 70, 71 Because of these corrosion concerns, actions
are usually taken to accommodate ethanol in ethanol production,
storage, and distribution systems, as well as in vehicles and engines.
Such actions include the careful selection of materials and/or the use
of appropriate ethanol compatible coatings on susceptible metal parts
that come into contact with the ethanol fuel, as well as the use of
corrosion and biocide additives.
---------------------------------------------------------------------------

    \65\ SAE 750124, ``Racing Experiences with Methanol and Ethanol-
Based Motor-Fuel Blends,'' T. Powell, Automotive Engineering
Congress and Exposition, Detroit, Michigan, February 24-28, 1975.
    \66\ SAE 912413 ``An Overview of the Technical Implications of
Methanol and Ethanol as Highway Motor Vehicle Fuels,'' Frank Black,
U.S. Environmental Protection Agency, Research Triangle Park, N.C.
    \67\ Nakaguichi, G.M., ``Ethanol Fuel Modifications for Highway
Vehicle Use-Final Report,'' U.S. DOE Contract EY-76-C-04-3683, NTIS
document ALO-3683-T1, Washington, DC July, 1989.
    \68\ Microbiologically Influenced Corrosion of Galvanic Steel,
Frederick J. Passman, PhD, Biodeterioration Control Associates,
Princeton, NJ, USA., ASTM Workshop on Fuel Corrosivity, July, 2010.
    \69\ Behavior of Corrosion Inhibitor Acids In Fuel/Water Blends,
Andrew McKnight, PhD, Innospec, Newark, DE, USA, ASTM Workshop on
Fuel Corrosivity, July 2010.
    \70\ Interaction of Contaminants with Pipeline Corrosion
Inhibitors, Joseph Stark, PhD, Baker Hughes, Sugarland, TX, USA,
ASTM Workshop on Fuel Corrosivity, July 2010.
    \71\ Diesel Soap--Formation and Related Problems, Richard
Chapman, BP Global Fuel Technology, Naperville, IL, USA, ASTM
Workshop on Fuel Corrosivity, July 2010.
---------------------------------------------------------------------------

5. Solvency
    Ethanol can also act as a solvent for various materials. As such,
ethanol has historically been known to remove or dissolve components
built up in the fuel storage, handling and delivery systems (e.g. fuel
tank, fuel lines, injectors, etc.). Once these components are loosened
or partially dissolved, they are transported through the fuel system,
and if excessive, may cause fuel filter, injector plugging or other
component problems, all of which can lead to poor operability and
degraded emission performance. Gasoline-ethanol blends may also pick up
contaminants from storage tanks and delivery trucks. The amount of
build-up is related to a combination of fuel composition properties and
fuel usage patterns (i.e., regular fuel usage versus infrequent, etc.).
Non-automotive equipment may experience fuel filter plugging related
more to extended storage periods where gasoline can deteriorate and
lead to more deposits requiring a plugged fuel filter replacement.
6. Volatility
    Fuel volatility is a measure of a fuel's vapor pressure or its
tendency to vaporize. When ethanol is blended into gasoline, the
hydrogen bonding between the ethanol molecules is weakened
significantly and the alcohol ``depolarizes.'' This results in higher
Reid Vapor Pressures (RVP) for gasoline containing ethanol. Ethanol's
effects on RVP have been well documented,\72, 73, 74\ where low level
ethanol blends, in general, will increase gasoline RVP by up to one
pound per square inch with the maximum effect occurring at
approximately 3 vol% ethanol concentration. The RVP of the base fuel
will also influence just how much increase will occur by the addition
of ethanol.\75\ Increases in RVP result in increased vapor generation
and increased evaporative emissions.
---------------------------------------------------------------------------

    \72\ J.L. Keller, ``Methanol and Ethanol Fuels for Modern Cars,
44th Refinery Mid-year Meeting/Session on Fossil Fuels in 1980's,
Reprint No. 08-79, May 15, 1979.
    \73\ F.W. Cox, Physical Properties of Gasoline/Alcohol
Automotive Fuels, Presented at the Alcohol Fuel Technology
Conference, May 28-31, 1979.
    \74\ SAE 912413 ``An Overview of the Technical Implications of
Methanol and Ethanol as Highway Motor Vehicle Fuels,'' Frank Black,
U.S. Environmental Protection Agency, Research Triangle Park, N.C.
    \75\ SAE 861178, ``The Properties and Performance of Modern
Automotive Fuels,'' P. Dorn, A.M. Mourao, and S. Herbstman, Texaco
Research Center, Beacon, N.Y.
---------------------------------------------------------------------------

    Additionally, while ethanol at certain levels may raise the general
volatility of the gasoline-ethanol blend, because of ethanol's single
boiling point and high latent heat of vaporization, the ethanol
fraction may cause combustion difficulties and increased emissions
during the start of some spark-ignition engines when the engines are
cold, particularly at colder start temperatures. Further, once the
engine is hot, the single boiling point can also cause difficulty in
operating and starting a hot engine as observed in older motor vehicles
when ethanol first became available. The ethanol would reach its
boiling point in the fuel system and result in what is known as ``vapor
lock.''

C. Model Year 2000 and Older Light-Duty Motor Vehicles

    Ethanol impacts motor vehicles in three primary ways. First, as
discussed in Section VI.B.1 above, ethanol enleans the A/F ratio which
leads to increased exhaust gas temperatures and therefore potentially
incremental deterioration of emission control hardware and performance
over time. Second, over time, enleanment caused by ethanol can
ultimately lead to catalyst failure. Third, ethanol can cause material
compatibility issues which may lead to other component failure.
Ultimately, all of these impacts may lead to exhaust and/or evaporative
emission increases.
1. Enleanment
    MY2000 and older light-duty motor vehicles have much less
sophisticated emissions control systems compared to today's motor
vehicles and, as described below, may experience conditions that lead
to both immediate emission increases and increases over time if
operated on E15. Vehicles produced prior to the mid-1980s were equipped
primarily with carbureted engines. The A/F ratio of the carburetor is
preset at the factory based on the expected operating conditions of the
engine such as ambient temperature, atmospheric pressure, speed, and
load. As a result, carburetors have ``open loop'' fuel control which
means that the air and fuel are provided at a specified, predetermined
ratio that is not automatically adjusted during motor vehicle
operation. As fuel composition can vary, an engine with a carburetor
and open loop fuel control would never know whether it achieved the
desired A/F ratio. Since the motor vehicles at this time operated
``open loop'' all of the time with no ability to react for changes in
the A/F ratio, the addition of ethanol to the fuel tended to make the
A/F ratio leaner--closer to stoichiometry, which had the immediate
effect of reducing HC and CO emissions, but increasing NOX
emissions. However, some of these older open loop systems already
operate at the lean edge of combustion on current commercial fuels so
an increase in ethanol may cause them to begin to misfire resulting in
HC and CO increases.
    As a result of the Clean Air Act, EPA established standards and
measurement procedures for exhaust, evaporative, and refueling
emissions of criteria pollutants. From 1975 into the 1980s, motor
vehicles became equipped with catalytic converters, first with
catalysts capable of oxidizing HC and CO, and then, in response to
EPA's ``Tier 0'' standards, with three-way catalysts that also reduced
NOX. Motor vehicles produced in the 1980s and even more so
in the 1990s as a result of more stringent California and Federal
(e.g., ``Tier 1'') standards evolved to incorporate more sophisticated
and durable emission control systems. These systems generally included
an onboard computer, oxygen sensor, and electronic fuel injection with
more precise closed-loop fuel compensation and therefore A/F ratio
control during more of the engine's operating range. However, even

with the use of closed loop systems through the late 1990s, the
emission control system and controls remained fairly simple with a
limited range of authority and were primarily designed to adjust for
component variability (i.e., fuel pressure, injectors, etc.) and not
for changes in the fuel composition. During this period, ethanol was
only available in very limited areas of the US so the manufacturers'
designs of the emission controls and the durability of emission control
hardware generally did not account for the increased oxygen content of
ethanol. As a result, this generation of vehicles certified to Tier 0
and early Tier 1 emission standards operated leaner on ethanol, causing
immediate emission impacts (lower HC and CO emissions, higher
NOX emissions) and may have also deteriorated at different
rates when exposed to ethanol. These designs continued to evolve during
the early period of the Tier 1 emission standards as manufacturers and
component suppliers gained experience with vehicles in-use. However,
the largest improvements to emission controls and hardware durability
came after 2000 with the introduction of several new emission standards
and durability requirements forcing manufacturers to better account for
the implications of in-use fuels on the evaporative and exhaust
emission control systems.
    While most motor vehicles are operating today on E10, motor
vehicles operated on E15 will likely run even leaner than those
operated on E10 depending on the motor vehicle technology and operating
conditions. Enleaned combustion leads to an increase in the temperature
of the exhaust gases. This increase in exhaust gas temperatures has the
potential to raise the temperatures of various exhaust system
components (e.g., exhaust valves, exhaust manifolds, catalysts, and
oxygen sensors) beyond their design limits. However, based on past
experience, the most sensitive component is likely the catalyst,
particularly in older motor vehicles with early catalyst technology.
Catalyst durability is highly dependent on temperature, time, and fuel
gas composition. Catalyst temperatures must be controlled and catalyst
deterioration minimized during all motor vehicle operation modes for
the catalyst to maintain high conversion efficiency over the motor
vehicle's life. This is particularly important during high load
operation of a motor vehicle where high exhaust gas temperatures are
encountered and the risk for catalyst deterioration is highest.
Catalysts that exceed temperature thresholds will deteriorate at rates
higher than expected, compromising the motor vehicle's ability to meet
the required emission standards over its full useful life. Extended
catalyst exposure to higher exhaust temperatures can accelerate
catalyst thermal deactivation mechanisms (e.g., sintering of active
precious metal sites, sintering of oxygen storage materials, and
migration of active materials into inert support materials). While this
damage can occur at a highly accelerated rate with a sudden change in
temperature (e.g., with a misfire allowing raw fuel to reach the
catalyst), it is more likely to occur over time from elevated exhaust
temperatures as may be experienced with frequent or even occasional
exposure to E15. This deterioration may adversely affect a motor
vehicle's ability to control emissions, particularly after significant
mileage accumulation.
    Some motor vehicles may be able to manage catalyst temperatures by
compensating for the oxygen in the fuel under all operating conditions,
including high loads. This is achieved by using a closed-loop fuel
system that measures the A/F ratio and makes the appropriate
corrections to maintain the A/F ratio in the very tight ban of
operation around stoichiometry necessary for optimum catalyst
performance and reductions in HC, CO, and NOX emissions. The
part of the closed-loop fuel system that is responsible for the
correction to the A/F ratio is referred to as ``fuel trim.'' The fuel
trim adds or removes fuel to the engine to maintain the required A/F
ratio. If the measured A/F ratio has insufficient oxygen, or is
``rich'' compared to what the engine needs, the fuel trim will instruct
the fuel injectors to inject less fuel, making the A/F ratio
``leaner.'' The opposite is true if the measured A/F ratio has too much
oxygen and needs to inject more fuel for a ``richer'' A/F ratio. The
fuel trim is generally comprised of two major parts, short term fuel
trim and long term or adaptive learned fuel trim. Learned fuel trim,
also known as adaptive fuel trim, can also be applied to open loop
operation such as high load or wide open throttle to alleviate the
catalyst temperature increases caused by operating on E15 fuel.
However, while this strategy was more common in later model years
closer to MY2000, it was not consistently employed by all
manufacturers. Some manufacturer models may have less range of
authority than others and some may require longer periods of time to
adapt. Hence, control algorithms and calibrations used by some
manufacturers may be more effective than others.
    The fuel trim has a limited range of adjustment in which it can
continue to update the A/F ratio and maintain the fuel system at or
near stoichiometry. For MY2000 and older light-duty motor vehicles, the
fuel trim range is generally more limited than the range for newer
light-duty motor vehicles, and MY2000 and older motor vehicles may use
their full range of fuel trim adjustment to account for normal
component deterioration. Injectors, sensors and changes to fuel
pressure may shift with time and aging to use all of the fuel trim's
range of adjustment. The additional oxygenate in E15 may actually shift
the A/F ratio more than the earlier introduction of E10 if the engine's
A/F ratio feedback cannot compensate because it has reached its
adjustment limit. In short, MY2000 and older motor vehicles are at risk
of having insufficient thermal margins to accommodate ethanol blends up
to E15 due to the limits of their fuel trim range.
    Test data to confirm or refute concerns over the use of E15 in
older vehicles is very limited in scope and content. The available data
do not prove or disprove the concerns, although there are several
studies that support the potential for long term durability issues
consistent with engineering theory. Three studies--the CRC Screening
Study, DOE Pilot Study, and the Orbital Study--discussed in section
IV.A. highlight in particular the concern with MY2000 and older motor
vehicles. The CRC Screening Study (E-87-1) was a test program developed
to look at the effects of mid-level ethanol blends on U.S.
vehicles.\76\ This screening study was the first phase of a two-phase
study evaluating the effects of mid-level ethanol blends on emission
control systems. The purpose of this first phase of the study was to
identify vehicles which used learned fuel trims to correct open loop
air-fuel rations. Under the test program a fleet of 25 test vehicles
was identified and acquired with six of those vehicles being MY2000 and
older. The study collected vehicle speed, oxygen sensor air-fuel-ratio,
and catalyst temperature data for four fuels (E0, E10, E15, and E20).
The results of the three ethanol blended fuels compared to E0 showed
that four of the six MY2000 and older vehicles tested failed to apply
long-term fuel trim to open loop operation in order to compensate for
increasing ethanol levels. And that these

same four vehicles exhibited increased catalyst temperatures when
operated on E20 as compared to E0. While the subsequent DOE Catalyst
Study concluded that this learned fuel trim was not important for
MY2007 and newer motor vehicles because they are durable (and therefore
can handle E15) as discussed in section IV.A, there was no such follow
on program for MY2000 and older motor vehicles so the durability of
these vehicles on E15 is unknown.
---------------------------------------------------------------------------

    \76\ Mid-level Ethanol Blends Catalyst Durability Study
Screening (CRC Report: E-87-1), June 2009 (``CRC Screening Study'').
http://www.crcao.com/reports/recentstudies2009/E-87-1/E-87-
1%20Final%20Report%2007_06_2009.pdf
---------------------------------------------------------------------------

    Another study suggests that many MY2000 and older motor vehicles
may also have emission exceedances if operated on E15. In 2003, the
Orbital Engine Company issued a report on the findings of vehicle
testing it completed to assess the impact of E20 on the Australian
passenger vehicle fleet. While the Australian vehicles in this study
were not representative of U.S. vehicles of the same model years, they
are similar to MY2000 and older U.S. motor vehicles with respect to
technology and emission standards. The testing program covered vehicle
performance and operability testing, vehicle durability testing, and
component material compatibility testing, on nine different vehicle
makes or models, five vehicles from MY2001 and four vehicles from
MY1985 to MY1993. Testing results showed increases in exhaust gas
temperature in five of the nine vehicles tested with three showing
increases in catalyst temperature. Enleanment was found to occur in six
of the nine vehicles tested, with three having closed loop control--the
old vehicles without closed loop control all displayed enleanment. In
general, the increase in exhaust gas temperature was found to follow
those vehicles with enleanment. Furthermore, one vehicle in the study
experienced catalyst degradation sufficient to make the tested vehicle
no longer meet its applicable Australian emission standards.
    EPA recently received a report by Ricardo \77\ commissioned by the
Renewable Fuels Association specifically discussing the potential
impacts of E15 on MY1994-2000 light-duty motor vehicles. However, as
discussed in the decision document, it sheds little new light on the
potential emission impacts of E15 on MY2000 and older motor vehicles.
While arguing that many MY1994-2000 motor vehicles may be designed to
be compatible with E15, it did so only for ``properly engineered''
vehicles. Furthermore, it acknowledged potential emission increases in-
use, but in the context of the waiver decision highlighted that they
were likely within manufacturer compliance margins. Finally, it drew
many of its conclusions only relative to E10, not to E0.
---------------------------------------------------------------------------

    \77\ Ricardo Inc., Technical Assessment of the Feasibility of
introducing E15 Blended Fuel in U.S. Vehicle Fleet, 1994 to 2000
Model Years, 10 September, 2010. EPA Docket  EPA-HQ-OAR-
2010-0448.
---------------------------------------------------------------------------

    Hence, based on the limited data available and our engineering
judgment, we conclude that MY2000 and older motor vehicles have the
potential to experience conditions when operated on E15 which may
ultimately lead to an increase in emissions.
2. Material Compatibility
    Data and information exist in the literature regarding ethanol's
impacts on motor vehicle material compatibility. Engine, fuel system,
and emission control materials (metals, plastics, and elastomers) must
maintain their integrity for motor vehicles to meet their exhaust and
evaporative emissions standards. Material incompatibility can result
from the chemical reaction or physical interaction between a fuel and
material with which it comes into contact. This can lead to emissions
compliance problems not only immediately upon using the new fuel or
fuel additive, but especially over time. In most cases one would expect
any materials incompatibility to show up in the emissions tests, but
there may be impacts that do not show up due to the way the testing is
performed or because the tests simply do not capture the effect. As a
result, along with emissions testing, materials compatibility is a key
factor in assessing the emissions durability of a fuel or fuel
additive.
    Based on our engineering assessment, it appears that manufacturers
took varying steps at different points in time to transition the
materials in their motor vehicle designs to be E10 compatible. Many in
the mid-to-late 1980s took steps for E10 compatibility at least for the
more immediate effects of ethanol (e.g., the dissolving of certain
elastomers). Large parts suppliers began testing materials on gasoline-
ethanol blends in the mid-to-late 1980s and early 1990s, but practices
varied with manufacturer. At the same time, certain areas have now had
E10 for a number of years and therefore motor vehicles in these areas
have experienced a much higher frequency of ethanol exposure. This has
led many to argue that ethanol is compatible for all motor vehicles in
the in-use fleet and therefore E15 should be too. However, since the
effects would be long term, it is difficult to assess whether these
motor vehicles experienced any higher rates of deterioration or
component failure on E10. Furthermore, material compatibility with
ethanol is time, condition (e.g., temperature, pressure), and
concentration dependent, such that problems may occur with E15 that did
not show up with E10.
    Moving from E10 to E15 reflects a 50% increase in the volume of
ethanol present in gasoline. Therefore, since the impacts of ethanol on
materials are a function of concentration, E15 has the potential to
have more significant impacts than E10 if used in motor vehicles not
equipped for it. For MY2000 and older motor vehicles, E15 use may
result in degradation of metallic and non-metallic components in the
fuel and evaporative emissions control systems that can lead to highly
elevated hydrocarbon emissions from both vapor and liquid leaks.
Potential problems such as fuel pump corrosion or fuel hose swelling
would likely be worse with E15 than historically with E10, especially
if motor vehicles will be operating exclusively on it. Since ethanol
historically comprised a much smaller portion of the fuel supply (see
section VI.A.), in-use experience with E10 was often discontinuous or
temporary, while material effects are time and exposure dependent.
Thus, problems may surface with E15 that have not surfaced historically
in-use. Additionally, leak detection diagnostics did not appear until
MY1996 and enhanced evaporative test procedures were not fully
implemented until the late 1990s.
    In addition to potential vapor or liquid leaks, ethanol is also
known to facilitate permeation through the materials in the fuel
system. Studies have shown this to be a significant source of increased
emissions with gasoline-ethanol blends, especially on older motor
vehicles. Following additional testing requirements as part of the Tier
2 motor vehicle emission standards beginning in 2004, materials in
newer motor vehicles have been able to mitigate the permeation effects
of ethanol in the fuel, as discussed in the waiver decision document.
However, as shown in the Figure VI.C.2-1 below, permeation emissions
from older model year vehicles may be very high with ethanol
blends.\78\
---------------------------------------------------------------------------

    \78\ Diurnal testing refers to a process for measuring
evaporative emissions where a vehicle is placed in a sealed
enclosure and the temperature varied over multiple cycles to
simulate ambient day and night conditions in summertime. Enhanced
Evaporative Emission Vehicles (CRC Report: E-77-2), March 2010, and
Evaporative Emissions from In-Use Vehicles: Test Fleet Expansion
(CRC Report: E-77-2b), June 2010.

---------------------------------------------------------------------------

[GRAPHIC] [TIFF OMITTED] TP04NO10.005

    As part of its waiver application, Growth Energy submitted a series
of studies completed by the State of Minnesota and the Renewable Fuels
Association (RFA) that investigated materials compatibility of motor
vehicle engines and engine components using three test fuels: E0, E10,
and E20 (``Minnesota Compatibility Study'').\79\ The Minnesota
Compatibility Study looked at 19 metals (``Metals Study''),\80\ eight
elastomers (rubber materials) (``Elastomers Study''),\81\ eight
plastics (``Plastics Study''),\82\ and 24 common fuel sending unit and
fuel pump combinations (``Fuel Pumps Study'' and ``Fuel Pump Endurance
Study''),83, 84 currently used in automotive, marine, small
engine, and fuel system dispensing equipment for physical or chemical
effects due to ethanol.\85\
---------------------------------------------------------------------------

    \79\ ``The Feasibility of 20 Percent Ethanol Blends by Volume as
a Motor Fuel;'' State of Minnesota and Renewable Fuels Association.
    \80\ ``The Effects of E20 on Metals Used in Automotive Fuel
System Components;'' Bruce Jones, Gary Mead, Paul Steevens, and Mike
Timanus; Minnesota Center for Automotive Research at Minnesota State
University, Mankato; February 22, 2008.
    \81\ ``The Effects of E20 on Elastomers Used in Automotive Fuel
System Components;'' Bruce Jones, Gary Mead, Paul Steevens, and
Chris Connors; Minnesota Center for Automotive Research at Minnesota
State University, Mankato; February 22, 2008.
    \82\ ``The Effects of E20 on Plastic Automotive System
Components;'' Bruce Jones, Gary Mead, and Paul Steevens; Minnesota
Center for Automotive Research at Minnesota State University,
Mankato; February 21, 2008.
    \83\ ``The Effects of E20 on Automotive Fuel Pumps and Sending
Units;'' Nathan Hanson, Thomas Devens, Colin Rohde, Adam Larson,
Gary Mead, Paul Steevens, and Bruce Jones; Minnesota State
University, Mankato; February 21, 2008.
    \84\ ``An Examination of Fuel Pumps and Sending Units During a
4000 Hour Endurance Test in E20;'' Gary Mead, Bruce Jones, Paul
Steevens, Nathan Hanson, and Joe Harrenstein, Minnesota Center for
Automotive Research at Minnesota State University, Mankota; March
25, 2009.
    \85\ Effects assessed in the studies include: Pitting, surface
texture change, discoloration, or loss of mass for metals;
appearance, volume, weight, tensile strength, elongation, and
hardness for elastomers; mass loss or gain, volume loss or gain,
tensile elongation, impact resistance, and tensile strength for
plastics; and corrosion and longevity as measured by flow and
pressure tests for pumps and sending units.
---------------------------------------------------------------------------

    Results from the Minnesota study were mixed depending on if the
comparison was being made between E20 and E10 or E20 and E0. Some
materials were compatible with the ethanol blends while some displayed
larger property changes with the ethanol blends. Because of the immense
variety of materials available and the overlap in use of the different
materials over time, the study could not test all materials in the
fleet, nor did it directly assign the materials tested to a vehicle
generation or model year. Instead, the study generalized that because
ethanol was available in some parts of the U.S., these materials were
likely E10 compatible. However, these materials were used prior to the
widespread use of ethanol and therefore conceivably prior to many
manufacturer's requirement for prolonged exposure to ethanol and
specifically not for gasoline-ethanol blends above 10%. It is difficult
to quantify the overall impact of changes in any material due to
ethanol at E15 or E20 levels and what those changes would mean to the
older motor vehicle fleet, only that some portion of the fleet may
experience changes that could result in accelerated component failures
beyond what would be expected on E0 or E10. In addition, it is
important to note that the Minnesota Compatibility Study assessed
component parts using laboratory bench tests rather than durability
studies of whole motor vehicle fuel systems simulating ``real world''
motor vehicle use.

    In addition to providing comments on the Minnesota Compatibility
Study as discussed in the waiver decision document, the Alliance
commented that engines need to be hardened for resistance to ethanol.
Use of gasoline-ethanol blends in unhardened engines can result in
bore, ring, piston and valve seat wear. Deterioration of these
components can lead to compression and power loss, misfire and catalyst
damage.
    Based on our review of the literature and industry comments on the
E15 waiver request, we believe that MY2000 and older light-duty motor
vehicles have the potential for increased material degradation with E15
use. In addition, some MY2000 and older light-duty motor vehicles may
have been designed for only limited exposure to E10 while the oldest
vehicles on the road pre-date ethanol blends in the marketplace all
together. This potential for material degradation may make the
emissions control and fuel systems more susceptible to corrosion and
chemical reactions from E15 when compared to the E0 certification fuels
for these motor vehicles and may ultimately increase vehicle emissions,
especially for MY2000 and older motor vehicles.
3. Motor Vehicle Population and Anticipated Emissions Impact
    There is a long history of test programs that have been carried out
on light-duty motor vehicles and trucks that have quantified the
immediate emission impacts of blending ethanol up to 10 vol% into
gasoline. These test programs, dating back to the earliest days of
gasoline-ethanol blends, have found that the oxygen content of ethanol
enleans the A/F ratio in motor vehicles during open-loop operation,
causing a decrease in HC and CO emissions, but also results in a
corresponding increase in NOX emissions. These studies have
been used to develop emission models, such as the EPA Predictive Models
\86\ incorporated into the Agency's MOVES model,\87\ that have been
thoroughly peer reviewed. The result is that for a typical E10 blend of
gasoline, exhaust NMHC emissions have been found to decrease by about
5%, and NOX emissions to increase by about 6%, relative to
E0.\88\ While the magnitude of impact may vary by a few percent
depending on the motor vehicle technology and how other fuel properties
change when ethanol is blended into gasoline, the relative magnitude
and direction of the impacts remains consistent for typical fuels.\89\
The limited available data on E15 suggests that this trend continues,
and is slightly more pronounced due to the higher ethanol content.
However, these emission impacts are not the focus of this proposal as
their magnitude tends to be within vehicle compliance margins (the
difference between a vehicle's actual emission certification level and
the standard). Rather, for this proposal, we have focused on long-term
durability issues associated with E15, as discussed in more detail
below. The issue of immediate emission increases for E15 is more
properly addressed as part of the anti-backsliding study and rulemaking
under section 211(v) of the Act.
---------------------------------------------------------------------------

    \86\ A detailed description of the development of the EPA
Predictive Models is available in a Technical Support Document:
``Analysis of California's Request for Waiver of the Reformulated
Gasoline Oxygen Content Requirement for California Covered Areas'',
EPA420-R-01-016, June 2001.
    \87\ The Agency's MOVES model has undergone extensive peer
review and testing, and incorporates the EPA Predictive Models.
    \88\ These effects are based the EPA Predictive Models and are
generally consistent with conclusions of CRC E-74b report (e.g.,
Figure ES-2). Fuels properties evaluated were based on market
averages and were as follows: E0 had aromatics content of 29.5 vol%,
a T50 of 215 [deg]F, a T90 of 325 [deg]F, and an RVP of 8.9 psi and
E10 had aromatics content of 24.9 vol%, a T50 of 202 [deg]F, T90 of
325 [deg]F, and an RVP of 8.9 psi. Other parameters not mentioned
here were assumed to be held constant between the blends.
    \89\ Results based on data mostly from vehicle models that
predated the Tier 2 emission standards, so several recent test
programs have been focused on Tier 2 vehicles that will soon make up
the majority of the in-use fleet.
---------------------------------------------------------------------------

    Sufficient data do not exist to predict specific changes in
emission rates for the various motor vehicle technologies due to long-
term use of E15 blends. However, with respect to exhaust emissions, if
a catalyst were to be damaged to the point of having no significant
remaining functionality, we could expect NOX emissions
similar in magnitude to those in untreated engine-out exhaust (i.e.,
before treatment by the catalyst). If, in this situation, the fuel
control system continued to operate in closed-loop mode, NOX
emission levels in the range of 2-4 g/mi would be expected, or
approximately ten times the typical emissions rate for a properly
operating 1990s-era motor vehicle and about 60 times that of new cars
today.\90\ Similarly, loss of catalyst function could also cause
significant HC emission increases, where levels on the order of 2 g/mi
could be expected.\91\ This would be equivalent to combined HC
emissions of 40 new cars today. While this kind of complete failure
would likely be limited in nature, misfueled motor vehicles may
experience a reduction in catalyst efficiency earlier than intended,
resulting in emissions levels increased above current levels and up to
the uncontrolled engine-out levels presented above.
---------------------------------------------------------------------------

    \90\ See ``Effects of Gasoline Composition on Vehicle Engine-Out
and Tailpipe Hydrocarbon Emissions--The Auto/Oil Air Quality
Improvement Research Program'', SAE Paper No. 920329. See also
``Engine-out and Tail-Pipe Emission Reduction Technologies of V-6
LEVs'', SAE Paper No. 980674. A vehicle not operating in closed-loop
mode may emit more or less NOX depending on combustion
behavior. During the 1990s, Federal emission standards for
NOX dropped from 1 g/mi to 0.4 g/mi.
    \91\ See ``Effects of Gasoline Composition on Vehicle Engine-Out
and Tailpipe Hydrocarbon Emissions--The Auto/Oil Air Quality
Improvement Research Program'', SAE Paper No. 920329. See also
``Engine-out and Tail-Pipe Emission Reduction Technologies of V-6
LEVs'', SAE Paper No. 980674.
---------------------------------------------------------------------------

    Another area of concern related to exhaust emissions is fuel pump
malfunction occurring due to material incompatibility of higher ethanol
content with parts such as plastic pump rotors, shaft seals or
elastomeric tubing, and increased corrosion of metallic or electrical
components. As described in Section VI.B, ethanol increases the
electrical conductivity of fuel, increasing the likelihood that
galvanic corrosion of metal parts would occur. Before outright failure,
malfunctioning fuel pumps often provide inconsistent fuel pressure for
some period of time, resulting in long crank (starting) times,
misfires, and other erratic engine behavior. Should such conditions
occur, they may cause increases in exhaust emissions and possible
deterioration of exhaust catalysts.
    In addition to the potential for exhaust emissions increases,
evaporative emissions are also expected to increase, not only
immediately due to increased permeation (as discussed above), but also
due to long-term E15 use that may cause from increased corrosion of
metallic fuel system components and accelerated deterioration of
elastomeric hoses and seals. Corrosion may result in vapor or liquid
leaks, depending on where in the fuel system the corrosion is located.
Many types of elastomers used in o-rings and fuel lines swell or crack
when exposed to ethanol, resulting in increased permeation of vapor or
liquid leaks. Elastomeric seals on older motor vehicles may already be
brittle and weakened from age. Exposure to E15 may produce accelerated
failures of these elastomeric components.
    Though it is difficult to quantify the impacts of these types of
evaporative component failures, a recent evaporative emissions study
produced some relevant data. During the program, a motor vehicle with a
fuel system leak due to an o-ring failure produced between 23-26 times
more gasoline vapor during a pair of diurnal tests than

a properly-functioning new motor vehicle meeting current standards.\92\
The study also placed very small simulated leaks (essentially pin
holes) in gas caps of three motor vehicles, representative of what
could occur as a result of tiny corrosion sites in the vapor space of
the fuel tank. Diurnal tests were performed to compare the emissions
with and without the leaks. The MY1996 motor vehicle produced 54 times
more evaporative emissions with the simulated leak, while the MY2001
and 2004 motor vehicles produced two and three times more vapors,
respectively. The study authors point out that the two newer motor
vehicles had tank vent systems designed to meet onboard refueling vapor
recovery (ORVR) requirements, suggesting this may mitigate the effect
of vapor space leaks.\93\
---------------------------------------------------------------------------

    \92\ Diurnal testing refers to a process for measuring
evaporative emissions where a vehicle is placed in a sealed
enclosure and the temperature varied over multiple cycles to
simulate ambient day and night conditions in summertime. See
Coordinating Research Council Report No. E-77-2 for detailed results
(available at http://www.crcao.org).
    \93\ Onboard refueling vapor recovery systems were phased into
production in light-duty motor vehicles over MY1998-2000, and
provide a relatively short, large-diameter pathway for vapors to
reach the carbon canister where they are stored for combustion
during engine operation. See Coordinating Research Council Report
No. E-77-2 for detailed results (available at http://www.crcao.org).
---------------------------------------------------------------------------

    Thus, we may conclude that even small vapor space leaks occurring
in older motor vehicles (before ORVR was required) have the potential
to result in large increases in HC emissions.
    For more discussion on potential evaporative issues, refer to the
Waiver Decision document Section IV.A.3 that was also released today.
    Table V1.C.3-1 below shows the projected population of motor
vehicles--passenger cars and light-duty trucks in the fleet--by model
year for 2011. According to this information, of the total estimated
225 million cars and trucks that operate on gasoline in the fleet
today,\94\ nearly 73 million or one-third are MY2000 and older light-
duty motor vehicles, and it is these motor vehicles for which the
effects of E15 are uncertain but indicate the potential for anywhere
from small to significant emission increases from the deterioration of
the emissions control system over time. As discussed above, if motor
vehicles experience engine or emission component failure, the potential
exists for very elevated exhaust and/or evaporative system emissions
rates. If only a fraction of the fleet were to experience problems with
E15, that would still be a large number of motor vehicles with a
potentially significant impact on in-use emissions.
---------------------------------------------------------------------------

    \94\ There are approximately 250 million cars and trucks in the
fleet today when diesels are included.

               Table VI.C.3-1--Projected Population of Cars and Light Trucks by Model Year in 2011
----------------------------------------------------------------------------------------------------------------
                                                                             Cars and trucks
             Model year                      Cars           Light trucks         combined       Cumulative total
----------------------------------------------------------------------------------------------------------------
2000 and earlier....................         41,548,800         32,162,084         73,710,884         73,710,884
2001-2006...........................         46,567,413         38,594,752         85,162,165        158,873,049
2007-2011...........................         39,068,213         26,755,598         65,823,812        224,696,860
                                     ---------------------------------------------------------------------------
    Total...........................        127,184,425         97,512,435        224,696,860  .................
----------------------------------------------------------------------------------------------------------------
Source: EPA's vehicle certification data and Mobile Vehicle Emissions Simulator (MOVES) model.

D. Heavy-Duty Gasoline Engines and Vehicles

    Given its limited market, heavy-duty gasoline engines and vehicles
have not been the focus of test programs and efforts to assess the
potential impacts of E15 on such engines. From a historical
perspective, the introduction of heavy-duty gasoline engine and vehicle
technology has lagged behind the implementation of similar technology
for light-duty motor vehicles. Similarly, emission standards for this
sector have lagged behind those of light-duty motor vehicles, such that
current heavy-duty gasoline engine standards remain comparable from a
technology standpoint to older light-duty motor vehicle standards.
Consequently, we believe the discussion in Section VI.C. for MY2000 and
older motor vehicles should also be applicable to the majority of the
in-use fleet of heavy-duty gasoline engines and vehicles. Therefore, we
are proposing to prohibit the use of E15 in heavy-duty gasoline engines
and vehicles. We seek comment on this assessment.

E. Motorcycles

    Motorcycles come in many different sizes, styles and applications.
The biggest distinction between motorcycle types are that some are
designed for operation on-road and others are designed for operation
off-road. The motorcycles designed for operation on-road are referred
to as highway motorcycles. Highway motorcycles can range from small
scooters equipped with a 50 cubic centimeter (cc) single cylinder two-
stroke engine to a large touring motorcycle equipped with a multi-
cylinder four-stroke engine with an engine displacement exceeding 2,000
cc. Motorcycles designed for off-road operation are referred to as off-
highway motorcycles and can differ significantly from highway
motorcycles in design and appearance.
    Motorcycles have been around for well over 100 years. The fuel
system used to manage the A/F ratio for motorcycles has been the
carburetor. In fact, the carburetor has been the fuel control system of
choice for highway and off-highway motorcycles until the last decade.
Starting in the late 1990s, some of the more expensive high performance
highway motorcycles began to use electronic fuel injection (EFI) to
manage the A/F ratio. While EFI is becoming more common today in many
highway motorcycles, there are still many models that use carburetors.
Off-highway motorcycles have only begun to use EFI in a very few
expensive competition models. The vast majority of off-highway
motorcycles continue to use carburetors.
    All internal combustion engines need a system to cool the engine
from the excessive heat generated as part of the combustion process.
Without a cooling system, the engine would quickly overheat and fail.
Motorcycles use two types of engine cooling systems: liquid-cooled and
air-cooled. Liquid-cooled systems are very similar to the systems used
by automobiles. A radiator stores a liquid coolant that is distributed
throughout the engine which cools the engine. The heated coolant is
returned to the radiator where it is cooled by air from the moving
motorcycle or from an external fan. An air-cooled system is similar to
that used for most nonroad engines and is less sophisticated than a

liquid-cooled system. An air-cooled system uses a series of external
``fins'' located on the cylinders and cylinder heads that help direct
heat away from the cylinder and cylinder head. Since the engine in a
motorcycle is exposed to the atmosphere and not contained in an engine
compartment like an automobile, the engine is exposed to passing air as
the machine is operated on the road or trail. The passing air is
channeled through the fins and helps cool the cylinder and cylinder
head, which helps cool the combustion chamber, reducing the overall
engine temperature. Air-cooling is not nearly as effective at
controlling engine temperature as liquid cooling. One of the strategies
to help with engine cooling for engines that rely on air-cooling is to
operate the engine at an A/F ratio that is rich of stoichiometry. The
additional fuel helps reduce combustion temperature, keeping overall
engine temperature lower. For this reason, any increase in the A/F
ratio beyond that designed for at the time of manufacturing, such as
the enleanment resulting from ethanol, raises potential concerns.
    In 1978, EPA issued HC and CO emission standards for highway
motorcycles. There were no standards for NOX emissions. To
meet these standards, the vast majority of motorcycle models used the
approach of adjusting the A/F ratio rather than using any unique
emission control technologies, such as catalytic converters, EFI, and
air injection. For performance and durability purposes, most
motorcycles operated with an A/F ratio that was considerably rich of
stoichiometry. The strategy used to control HC and CO emissions was to
lean the A/F ratio from these rich values traditionally used for
maximum performance. As with light-duty motor vehicles, this strategy
resulted in lower HC and CO emissions, but caused an increase in
NOX emissions. Since there were no NOX emission
standards, the increased NOX emissions were allowed. This
strategy also resulted in complaints about vehicle performance and
driveability. As a result, a common practice was for motorcycle owners
to change the A/F ratio on their own to a richer setting that improved
the performance concerns, but also possibly resulted in an exceedance
of the emissions standards. These emission standards were unchanged
until 2006 when more stringent standards for HC and new standards for
NOX were introduced for MY2008.
    Off-highway motorcycles were unregulated until 2006. Beginning with
MY2006, off-highway motorcycles were required to meet emission
standards for HC, CO, and NOx emissions. In general, the overall
majority of motorcycles designed from 1978 through 2006 either used an
A/F ratio leaner than desired for maximum performance and durability to
comply with highway motorcycle emission standards or ran rich, in the
case of off-highway motorcycles, to help cool the engine and protect it
from overheating and failure. The practice of motorcycle owners
adjusting the A/F ratio to a richer setting to improve performance and
driveability was even more prevalent in the off-highway motorcycle
sector, especially for competition motorcycles where performance is an
important attribute.
    As E10 fuel has become more prevalent in the marketplace, many
owners of off-highway and older highway motorcycles have chosen to
either operate their motorcycles on E0 fuel whenever it is available or
have modified their A/F ratio to a richer setting. In fact, the
internet is full of blogs of motorcycle owners discussing concerns with
operation on E10 fuel and ways to avoid these concerns, including how
to change the A/F ratio setting. It is a violation of the CAA to modify
a certified motorcycle from its certified configuration. Changing the
A/F ratio from the certified setting would be considered tampering, yet
it is clear it is practiced in-use.
    For highway motorcycles designed to already operate leaner to
comply with emission standards, the use of E15 fuel would result in a
further leaning of the A/F ratio. These motorcycles were designed with
an optimized A/F ratio setting taking into consideration the delicate
balance of emissions, performance, and engine protection. Since most of
these motorcycles use carburetors, the A/F ratio is not easily adjusted
to adapt to the increased amount of oxygen in the A/F mixture. The
additional enleanment of the A/F ratio could cause an increase in
combustion temperature and ultimately engine temperature, potentially
resulting in an exceedance of the emission standards and engine
failure. For off-highway motorcycles that have typically been designed
to operate rich of stoichiometry for engine protection, the enleanment
of the A/F ratio could cause an increase in engine temperature beyond
what the engine was designed to accommodate and ultimately result in
engine failure. As a result of the increased enleanment resulting from
E15 fuel, more motorcycle owners may be tempted to adjust the A/F
setting of their motorcycles to protect vehicles from potential damage
resulting in possible exceedances of the emissions standards.
    In either case, the use of E15 fuel could cause engine damage and
emission increases for highway motorcycles built prior to 2008 and for
all off-highway motorcycles, regardless of age. For highway motorcycles
built after MY2008 there is the possibility that some models may be
able to successfully accommodate the use E15 fuel. For MY2008 and
beyond, there are a number of models that use EFI and catalytic
converters. The systems are similar to automotive closed-loop catalyst
systems. However, one of the advantages to modern Tier 2 light-duty
emission control systems is that they use very sophisticated fuel trim
learning systems that allow a very precise ``learning and adapting'' of
changes to the A/F ratio mixture. While many of today's motorcycle
models use closed-loop systems, they do not have the advanced fuel trim
control of today's motor vehicles, meaning they would most likely not
be able to accommodate the enleanment of the A/F ratio in the same
manner as today's motor vehicles. Their closed-loop technology is more
similar to that of MY2000 and older motor vehicles than to current
motor vehicles.
    In light of the above, while there is no actual E15 test data on
motorcycles, EPA believes that any operation of highway or off-highway
motorcycles on fuel containing E15 could result in engine damage and
emission increases for highway and off-highway motorcycles. It also
could have the unintentional result of encouraging motorcycle owners to
violate the CAA by tampering with the vehicles A/F ratio setting to
improve performance, driveability, and protect the engine from damage,
while at the same time significantly increasing hydrocarbon and CO
emissions. Therefore, we are proposing to prohibit the use of E15 in
all motorcycles (highway and off-highway) but seek comment on our
assessment.

F. Nonroad Engines, Vehicles, and Equipment (Nonroad Products)

1. Introduction
    The nonroad product market is extremely diverse which makes it
difficult to determine what the impacts of E15 use might be. However,
similar to older motor vehicles, it appears that nonroad products may
experience emissions increases related to enleanment and material
compatibility issues if operated on E15. This is based in large part on
the history of the design of nonroad products operating on E10 in
relation to the age of those products in the field, and the
implications of

extrapolating this in-use operating experience with E10 to E15.
    The majority of nonroad products are still carbureted, or have very
simplistic electronic fuel injection which cannot adjust the engine A/F
ratio, and do not have any onboard diagnostics to monitor engine
performance before components may fail. The experience of consumers
with E10 in nonroad products in the 1980s pushed most manufacturers to
take some steps to address enleanment and E10 material compatibility
issues at that time, either with changes in engine design or warnings
in consumer owner manuals (either to avoid ethanol blended fuels or
blends higher than 10%). However, the design practices and
recommendations varied across the industry due to the breadth of the
nonroad market (as highlighted in Table VI.F.1-1) and the wide range of
manufacturers, applications, and markets. The design practices also
continued to evolve over time in part due to emission regulations.\95\
While a review of current nonroad engine and equipment manufacturer Web
sites indicates a general acceptance of E10 use with the new products
being produced today, manufacturers continue to caution against any
higher level ethanol use, and marine manufacturers still caution
against E10 use.\96\ In addition, nonroad product manufacturers are
clearly still learning how to design for compatibility with E10 as
evidenced by a recent large recall of snowblowers due to corroded
carburetors.\97\
---------------------------------------------------------------------------

    \95\ The first exhaust emission regulations for nonroad products
began with Small SI Engines in 1997 and the last onroad categories
of Marine Inboard/Sterndrive and Snowmobiles will meet their first
exhaust emission standards in 2010. The design changes to comply
with the standards tended to enlean the A/F ratio of new engines
compared to prior engines and limit the ability to manually adjust
the A/F ratio, so while newer engines may use materials better
suited for ethanol, they may also be more susceptible to enleanment
concerns.
    \96\ See EPA-HQ-OAR-2010-0448, Submittal to Docket on Yamaha Web
site information.
    \97\ See EPA-HQ-OAR-2010-0448, CPSC, Health Canada and Toro
snowblower recall.

              Table VI.F.1-1--2010 Estimated Population of Nonroad Engines, Equipment and Vehicles
----------------------------------------------------------------------------------------------------------------
                                                                           Estimated 2010 in-use population
           Nonroad category              Typical equipment/vehicles                   (millions)
----------------------------------------------------------------------------------------------------------------
Small SI Engine......................  Handheld: Trimmers,            131.
                                        chainsaws, blowers, hedge
                                        trimmers.
                                       Nonhandheld: Lawnmowers,
                                        generators, riding tractors.
Marine Outboard......................  Outboard engines to power      10.
                                        fishing boats, pontoon boats.
Marine Sterndrive/Inboard............  Speed boats, Ocean going       2.
                                        fishing boats.
Marine Personal Watercraft...........  Jet skis, jet boats, etc.....  1.3.
All Terrain Vehicles.................  Four wheelers................  11.
Nonroad Motorcycles..................  Nonroad motorcycles..........  2.6.
Snowmobiles..........................  Snowmobiles..................  2.4.
Large SI.............................  Fork Lifts...................  0.24.
On-Highway Motorcycles...............  On-Highway Motorcycles.......  8 (2008 estimated population).
----------------------------------------------------------------------------------------------------------------

    In addition, as shown in Table VI.F.1-2, consumers are still using
a considerable amount of older nonroad products (e.g., marine engines)
that are not necessarily designed for E10 use. In recognition of this
situation, States such as Minnesota, Missouri, Oregon, and Washington
that have mandated the use of ethanol blends have also provided
exceptions to the mandate for sale of ethanol free gasoline (E0) for a
variety of nonroad products. In addition, Oregon has taken the
additional step of publishing a list of retail stations distributing E0
to assist their nonroad consumers in locating it.\98\
---------------------------------------------------------------------------

    \98\ See EPA-HQ-OAR-2010-0448, Oregon State Government Non-
Ethanol Fuel Supplier Listing.

    Table VI.F.1-2--2010 Estimated Active Nonroad Product Population
------------------------------------------------------------------------
                                            Nonroad SI,
                                             excluding       Marine SI
               Sales years                   marine SI      (thousands)
                                            (thousands)
------------------------------------------------------------------------
2007-2010...............................          98,255           3,155
2003-2006...............................          39,466           2,953
1999- 2002..............................           7,245           2,484
1995-1998...............................           1,253           1,828
1991-1994...............................             475           1,215
1987-1990...............................             208             656
1983-1986...............................              72             348
1979-1982...............................              28             177
1975-1978...............................              18             100
1971-1974...............................              11              50
1967-1970...............................               6              23
1963-1966...............................               3              10
                                         -------------------------------
    Total...............................         147,040          12,999
------------------------------------------------------------------------
Source: UnEPA Nonroad8a model.

2. Enleanment
    Given the relatively undeveloped technological design of the
nonroad product fleet for purposes of emissions control, one of the
main concerns with the use of E15 in nonroad products, as for older
motor vehicles, is the increased temperatures caused by enleanment of
the A/F ratio. With higher levels of ethanol, the stoichiometric
(ideal) A/F ratio becomes lower (i.e., more fuel is needed for the same
amount of air) due to the increased oxygen in the fuel; hence, the
nonroad products run leaner since they do not adjust to the fuel oxygen
content. Engines designed to operate on non-ethanol fuels (0 wt%
oxygen) are currently operating on E10, which typically contains about
3.5-3.7 wt% oxygen, and would operate on approximately 5.5 wt% oxygen
when operating on E15. As evidenced by various studies,\99\ enleanment
has an immediate impact on emissions, causing HC and CO emissions to
decrease and NOX emissions to increase. However, since the
HC and NOX impacts are directionally opposite, these
immediate impacts are of less concern than the impacts of long-term
operation and durability. Leaner operation increases cylinder and
exhaust temperatures that can lead to overheating of the engine. In
some cases this can lead to expansion of the engine block and pistons
and result in a seized engine. Increased combustion temperature can
also result in expansion and contraction of the engine block and head
metals which leads to loosening of the head bolts. With looser bolts,
the gap between the engine block and the head will open and the head
gasket can get damaged, which in turn damages other engine components
(e.g., intake and exhaust valves, manifolds, etc.) which can result in
increased emissions and potential engine failure.
---------------------------------------------------------------------------

    \99\ ``Effects of Intermediate Ethanol B lends on Legacy
Vehicles and Small Non-Road Engines, Report 1'', NREL/TP-540-43543
and ORNL/TM-2008/117, October 2008.
---------------------------------------------------------------------------

    The likelihood that nonroad products may experience such issues
with E15 is difficult to quantify. However, limited testing by DOE
\100\ showed some engine failures with E15, and this is not entirely
unexpected since nonroad products are particularly prone to enleanment
for several reasons. First, nonroad products remain primarily
carbureted and/or have open loop fuel control.\101\ This means they do
not have the ability to self-adjust the A/F ratio in-use for the
presence of ethanol in the fuel. The amount of enleanment an engine
experiences in-use depends on several factors, including manufacturing
variability, engine wear, and, importantly for E15, the A/F ratio
setting of the engine in comparison to the setting needed for the fuel
the engine is operating on. Engine manufacturers set the A/F ratio
settings at the time of production based on a number of factors
including the emission standards, expected deterioration of emissions
over time and the emission certification fuels.\102\ In-use engines are
Federally certified on E0, while engines certified to California
standards are certified on an MTBE blend (the equivalent oxygen content
of about E6 or about 2.0 wt% oxygen).\103\ Thus, when nonroad products
switch to using E10 in the field, they operate leaner than they were
set to operate and would operate leaner still on E15. Older nonroad
products may have more headroom to tolerate enleanment from ethanol
than newer engines. This is because manufacturers have tended to set
the A/F ratio for their newer engines closer to stoichiometry (less
rich) to meet newer, more stringent emission standards in recent
years.\104\ Second, the majority of nonroad products are air-cooled
(rely on fins designed into the engine block to dissipate heat and some
have a fan to aid in cooling) and fuel-cooled (rely on rich operation -
excess fuel--to cool certain engine components like exhaust valves and
manifolds). Thus, they are much less forgiving of temperature increases
that might result from enleanment. Third, nonroad products frequently
operate at wide open throttle for much of their duty cycle where
exhaust temperatures are highest.
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    \100\ ``Effects of Intermediate Ethanol B lends on Legacy
Vehicles and Small Non-Road Engines, Report 1'', NREL/TP-540-43543
and ORNL/TM-2008/117, October 2008.
    \101\ Of the nearly 1200 gasoline-fueled nonroad engine families
certified in 2010, only 36 are estimated to have closed loop
electronic fuel injection, and most of those are large spark-ignited
nonroad engines.
    \102\ Older nonroad products--those prior to emission
standards--tended to have A/F ratio adjustment screws so
knowledgeable consumers or maintenance facilities could adjust the
A/F ratio of the engine if it operating poorly. Manufacturers tended
to remove or limit the capability for such manual adjustments to
meet emission standards.
    \103\ Standards for some nonroad categories which require
evaporative emission certification on E10 and allow it as an option
for exhaust are just beginning to phase in.
    \104\ Some engines have been under emission regulation for 13
years while others are just falling under emission regulation. In
order to meet EPA emission standards, engines have either been
enleaned and/or taken on engine designs of a more efficient engine
such as a 4 stroke engine.
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    Additionally, as enleanment occurs, the potential for an engine to
reach its lean limit is increased. A lean limit is found when the
typical emissions trend for enleanment (decreased HC and CO emissions
and increased NOX emissions) reverses and results in
increased HC and CO and decreased NOX. The reversal of
emissions at the lean limit is a signal the engine is starting to
experience incomplete combustion and is beginning to experience
misfires, hence the increases in HC. This often results in engine
failure since the engine cannot operate for an extended period of time
under this condition. Results from a DOE pilot study on small SI
nonroad products confirmed the potential enleanment concerns.\105\
Several engines failed prior to reaching their full useful life, and
the emission results for one of these (a consumer market trimmer)
indicated that it indeed may have exceeded its lean limit when
operating on E15.
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    \105\ ``Effects of Intermediate Ethanol B lends on Legacy
Vehicles and Small Non-Road Engines, Report 1'', NREL/TP-540-43543
and ORNL/TM-2008/117, October 2008.
---------------------------------------------------------------------------

    Finally, as highlighted above in VI.C., catalysts are an emission
reduction technology that is sensitive to increases in exhaust
temperature that would result from the use of E15. Although not yet
commonly found on nonroad products, they began phasing-in on small SI
handheld engines in 2002. High exhaust temperatures are already a
concern with these catalysts due to the close location of the catalyst
to the combustion chamber (catalysts are located within the muffler
which is commonly attached to the engine block). The hotter combustion
temperatures from engine enleanment result in hotter exhaust
temperatures experienced by the catalyst and can increase the
likelihood of catalyst washcoat sintering. If sintered, the catalyst
becomes nearly useless. The likelihood that an engine/catalyst setup
would reach this state is dependent on the engine/catalyst design and
the production variability. Both of these vary from engine manufacturer
to engine manufacturer and engine to engine.
    These potential enleanment problems would also impact the emission
performance of engines operated on E15 over their full useful life.
Unfortunately, emissions data from nonroad products operated over their
full useful life on E15 is very limited and currently is known only to
exist for the small spark-ignition sector of nonroad engines. DOE
performed a pilot and durability study on four small SI engine models
operated

on E10 and E15.\106\ The HC emissions from a commercial string trimmer
engine were considerably higher after operation over the full useful
life on E15 in comparison to E10 (191% vs. 101% increases in HC).
Hydrocarbon emissions were similarly increased on a commercial
generator with E15 vs. E10 when tested over their full useful life (47%
increase for HC on E15 vs. 4.7% increase for E10) and for a consumer
power washer (150% increase on E15 vs. a 44% increase for E10 \107\ The
consumer blower engines tested did not make it to aging at full useful
life on E15. The blower engines did have catalysts, however, the study
was not able to analyze its effectiveness over time. If the catalyst on
the blower was to fail and the engine continued to operate, then the
engine could have emitted almost the same emissions as pre-regulation
engines (e.g., 100-120 g/kW-hr without a catalyst vs. 50 g/kW-hr with a
catalyst). Thus, while it was only a small test sample, it is clearly
suggestive that exhaust emissions may increase considerably with E15
over the full useful life of the engines. Furthermore, while the study
was only conducted on the small SI segment of the nonroad market, the
similarities between it and most other segments of the nonroad market
would raise similar concerns.
---------------------------------------------------------------------------

    \106\ ``Effects of Intermediate Ethanol B lends on Legacy
Vehicles and Small Non-Road Engines, Report 1'', NREL/TP-540-43543
and ORNL/TM-2008/117, October 2008.
    \107\ The NOX emission results on commercial engines
change less over time on E15 compared to E10, however they start at
a higher value at new engine condition on E15. (ref: ``Effects of
Intermediate Ethanol B lends on Legacy Vehicles and Small Non-Road
Engines, Report 1'', NREL/TP-540-43543 and ORNL/TM-2008/117, October
2008.)
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3. Material Compatibility and Corrosion
    Materials used in engine and fuel system components (e.g. metals,
plastics, and rubbers) must be compatible with the full range of
expected fuel compositions. Any deterioration of materials could result
in loss of function of critical engine components, which can result in
emissions increases from fuel leaks and equipment failure. Nonroad
products do not have onboard diagnostics to detect these conditions and
report it to the user prior to engine failure. Not much is known about
the use of E15 in nonroad products in real world use. However, concern
exists because, as discussed above in section VI.B., ethanol has
different material compatibility characteristics than gasoline, and
even products operating adequately on E10 today may have issues with
E15. In addition, the vast range of nonroad product designs and
technologies over the years indicates that material incompatibility may
exist in portions of the in-use fleet when using E15.
    Motor vehicle manufacturers, as discussed in section VI.G, were
driven by both market forces and EPA emission standards to redesign
motor vehicles and upgrade materials for continual use of E10. This is
not the case for nonroad products. We are not aware of any standard
design practices self imposed by industry in relation to the presence
of ethanol in gasoline either in the early 1980s with gasohol in the
Midwest or in the 2000s as gasoline-ethanol blends expanded nationwide.
As a result, it appears that manufacturers used a variety of approaches
at different points in time in response to market conditions. One
reason for this is that the nonroad market serves a wide range of
consumers--the low cost consumer quality and the higher cost
professional quality--and the target market may govern how decisions
are made. Another reason is the vast diversity of nonroad products as
discussed above. The wide range of engines, applications,
manufacturers, and markets leads to a wide range of equipment design
practices. Finally, some manufacturers of nonroad vehicles and
equipment may purchase another manufacturer's engine and modify it and/
or its fuel system for a different application (e.g. purchasing a small
SI engine and replacing the fuel tank with a different design so it
fits in the equipment, or marinizing an automotive engine for use as a
marine engine and recertifying). Since there have been no evaporative
requirements for small SI engines until the Phase 3 standards
(beginning in 2009), in prior years the hoses and tanks could be
changed without concern. Consequently, even engine fuel systems
designed for the presence of ethanol by the original engine
manufacturer may be compromised by the vehicle/equipment manufacturer.
Thus, it is very difficult to quantify the volume of nonroad products
in today's fleet designed to operate on E10 let alone E15. As shown in
Figure VI.A-1, since E10 now represents more than 80% of the gasoline
market, it is clearly being used in nonroad products today. However, as
shown in Figures VI.A-3 and VI.A-4 the expansion of E10 nationwide is
still a relatively recent event and the effects we are focused on are
effects from longer term use of the fuel.
    Based on manufacturer Web sites and owner's manual recommendations,
most new nonroad products produced today are designed to be compatible
with E10. The main exceptions are marine applications (as well as
aircraft, which are not nonroad for purposes of section 211(c), but in
some cases use the same gasoline as nonroad products). The transition
appears to have occurred at different points in time across the market.
However, this is not to say that these engines have been designed to be
compatible with E15. The effects of ethanol are time and concentration
dependent such that the effects of E15 may be more severe than E10 on
materials. Consequently, manufacturers, while approving the use of E10
today, now also warn against the use of any higher gasoline-ethanol
blends.
    Unlike motor vehicles, most nonroad products are used periodically
and not for daily tasks. Many of these products are designed to be
inexpensive consumer products that last a relatively short time or are
used irregularly and for short periods of time. However a considerable
fraction may remain in the in-use fleet for a long time (10-40+ years).
Table VI.F.1-2 shows an estimated age distribution of nonroad products
in 2010. Marine engines are separated in the table to illustrate the
fact that these products in particular remain in the fleet for many
years. Consequently, even if nonroad products today are designed by the
manufacturer for the presence of 10% ethanol in the gasoline, a large
number of pieces of equipment still exist in the field from model years
when ethanol was not present in gasoline, or was just beginning to be
introduced into the fuel stream. Based on subsequent experience, some
of this equipment may operate fine on E10, while others may have
complications due to the enleanment or material incompatibility effects
of using ethanol.
    There have been several attempts to study the material
compatibility of E15 use in nonroad engines, vehicles and equipment.
However, the broad range of equipment and designs over time make it
extremely difficult to do any definitive study on the nonroad sector
that would address the entire fleet. A literature and information
search prepared by the University of Minnesota Center for Diesel
Research outlines a number of the concerns with ethanol that could be
experienced with E15.
--Corrosion of steel is accelerated by the presence of alcohols in the
fuel, both because the ethanol itself is considered to be more
corrosive but also because it is a solvent that removes oils and
coatings from the surface that might protect against corrosion. In
addition, ethanol attracts and mixes with water which is also corrosive
and tends to create a slightly acidic solution, especially over time.

--Elastomers exposed to higher gasoline-ethanol blends over time can
increase in weight gain, swell, soften and increase in hardness when
dried and as a result lose tensile strength, causing fuel pumps and
fuel lines to fail. For fuel hoses, swelling and softening creates a
risk of failure of the joints. The swelling and softening of O-rings,
seals and gaskets causes a risk of damage or incorrect fit of the seal
during assembly of joints leading to fuel leakage.
--Seals and gaskets on equipment that have not been previously exposed
to higher alcohol fuels could deteriorate and break down creating
leakage.
--Fiberglass-reinforced plastic fuel tanks, such as those on marine
engines and motorcycles, may also experience problems depending on the
type of resin and how much the ethanol will contribute to the corrosion
of it.
--Materials such as lead/tin-coated steel used in fuel tanks and
aluminum fuel system components require corrosion inhibitors due to the
presence of the higher alcohol in E15.
    In addition, four studies have been reported which tested the
effect of a number of ethanol containing fuels (E10, E20) on materials
compatibility of polymers, metal, and elastomers in motor vehicles and
nonroad engines. While none of these studies reported on E15, a number
of reports gave conditions seen on E10 and E20 and so results for E15
can be interpolated. The results of one technical assessment, published
in 2002,\108\ of E10 and E20 on two 2-stroke engines indicated
materials compatibility concerns for E20 for both engine types,
including effects on some polymeric materials that were deemed
unacceptable and E20 tarnishing and corroding brass and aluminum parts.
Similarly, three other studies conducted by the University of Minnesota
published in 2008 on metal, plastic, and elastomer materials,
respectively,109, 110, 111 used in highway vehicles and
nonroad products found a variety of impacts with E20 relative to E10 or
E0, including clear incompatibility with some materials. The existence
of such materials on equipment in the in-use fleet could lead to
increased emissions, fuel leaks, and potentially engine failure from
longer term use of E15. The degree to which such incompatible materials
exist in the in-use fleet is unknown, but it is clear that they do
exist based on in-use experience with E10.112, 113
---------------------------------------------------------------------------

    \108\ ``A Technical Assessment of E10 and E20 Petrol Ethanol
Blends Applied to Non-Automotive Engines. Failure Mode and Effects
Analysis of Engine Function and Component Design for Mercury Marine
15hp Outboard and Stihl FS45 Line-Trimmer Engines,'' conducted by
Orbital Engine Company, Report to Environment Australia, November
2002.
    \109\ ``The Effects of E20 on Metals Used in Automotive Fuel
System Components,'' by Bruce Jones, Gary Mead, Paul Steevens and
Mike Timanus, Minnesota Center for Automotive Research at Minnesota
State University, Mankato, February 22, 2008.
    \110\ ``The Effects of E20 on Elastomers Used in Automotive Fuel
System Components,'' by Bruce Jones, Gary Mead, Paul Steevens, and
Mike Timanus, Minnesota Center for Automotive Research at Minnesota
State University, Mankato, February 22, 2008.
    \111\ ``The Effects of E20 on Plastic Automotive Fuel System
Components,'' by Bruce Jones, Gary Mead, and Paul Steevens,
Minnesota Center for Automotive Research at Minnesota State
University, Mankato, February 21, 2008.
    \112\ http://www.fuel-testers.com/marine_e10_bad_gas_
reports.html.
    \113\ http://www.sail-world.com/USA/
index.cfm?SEID=0&Nid=38442&SRCID=0&ntid=0&tickeruid=0&tickerCID=0.
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    We are not aware of any testing that has been done that might help
quantify the potential impact on emissions from the types of engine
problems that would result from material compatibility problems.
However on July 14, 2010 the United States Consumer Protection Safety
Commission (CPSC) and Health Canada (HC) announced a recall of Toro
snowblowers stating that ``Exposure to ethanol in gasoline can cause
the carburetor needle to become corroded. A corroded needle can stick
in the open position and allow fuel to leak from the carburetor.''
\114\ Clearly fuel leaks would result in a considerable increase in
evaporative emissions, and material issues with carburetors, fuel
pumps, and other engine components could clearly lead to significant
changes in exhaust emissions, if not engine survivability.
---------------------------------------------------------------------------

    \114\ See EPA-HQ-OAR-2010-0448, CPSC, Health Canada and Toro
snowblower recall.
---------------------------------------------------------------------------

4. Phase Separation and Solvency/Detergency
    Two additional concerns with E10 use in nonroad products are phase
separation and solvency/detergency (see section VI.B.). However, if
nonroad products have already been operating on E10, the degree to
which these would be a concern with E15 is unknown. Phase separation
occurs if a gasoline-ethanol blend is saturated with water. Phase
separation is more likely in nonroad products due to the fact that
these engines are typically used only seasonally or occasionally
throughout the year and in the case of marine applications, the
equipment is generally in a humid, water environment. In addition,
specifically for small SI engines, some of the fuel systems are open to
the atmosphere through a direct vent in the gas cap which exposes the
fuel to air and humidity. If phase separation occurs, it has been
reported by repair shops to be acidic and result in corroded
carburetors and potential fuel line leaks. However, while phase
separation has been and continues to be a significant concern with E10,
as evidenced by ongoing guidance on manufacturer literature \115\ and
nonroad engine Web sites,\116\ the additional ethanol in E15 would
increase the water tolerance of the blend and thereby potentially
reduce the frequency of phase separation occurring.
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    \115\ See EPA-HQ-OAR-2010-0448, Collection of manufacturer
literature from 1980 to present.
    \116\ See EPA-HQ-OAR-2010-0448, Submittal to Docket on Yamaha
Web site information.
---------------------------------------------------------------------------

    Similarly, in areas that have transitioned to E10, problems have
historically also shown up in repair shops due to the solvency/
detergency characteristics of ethanol. Ethanol has been known to
dislodge sludge and varnish in the fuel system, causing it to clog fuel
filters and carburetors. However, if in-use engines have already been
operated on E10, the cleansing effect of the ethanol may have already
occurred, and transitioning to E15 may not result in any additional
problems.

G. Model Year 2007 and Newer Light-Duty Motor Vehicles

    MY2007 and newer light-duty motor vehicles are covered by EPA's
Tier 2 program which established dramatically more stringent
NOX standards. While the program allowed the standards to
phase in from MY2004 through MY2009, manufacturer certification data
show that gasoline-fueled motor vehicles actually reached full
implementation with MY2007. MYs 2004-2006 included a mix of vehicles--
some Tier 2 and some non-Tier 2. Tier 2 motor vehicles are more
technologically advanced and robust than cars built years ago, are
fully capable of running on E10, and must have their evaporative
emission systems aged on E10 for durability purposes. Sophisticated
computer systems and sensors constantly monitor the engine and the
exhaust to be sure that everything (i.e., the A/F ratio mixture) is
kept at its optimum level. All auto manufacturers now warrant their new
motor vehicles to operate on E10 or less. As found in the E15 waiver
decision also published today, we believe on the basis of testing