[Federal Register Volume 60, Number 239 (Wednesday, December 13, 1995)]
[Notices]
[Pages 64051-64056]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-30405]



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ENVIRONMENTAL PROTECTION AGENCY
[FRL-5344-6]


Retrofit/Rebuild Requirements for 1993 and Earlier Model Year 
Urban Buses; Public Review of a Notification of Intent To Certify 
Equipment

AGENCY: Environmental Protection Agency.

ACTION: Notice of agency receipt of a notification of intent to certify 
equipment and initiation of 45-day public review and comment period.

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SUMMARY: Twin Rivers Technologies' (TRT) has submitted to the Agency a 
notification of intent to certify urban bus retrofit/rebuild equipment 
pursuant to 40 CFR Part 85, Subpart O. The notification describes 
equipment consisting of biodiesel fuel additive in combination with a 
particular exhaust system catalyst. Pursuant to Sec. 85.1407(a)(7), 
today's Federal Register notice summarizes the notification, announces 
that the notification is available for public review and comment, and 
initiates a 45-day period during which comments can be submitted. The 
Agency will review this notification of intent to certify, as well any 
comments it receives, to determine whether the equipment described in 
the notification of intent to certify should be certified. If 
certified, the equipment can be used by urban bus operators to reduce 
the particulate matter of urban bus engines.
    The notification of intent to certify, as well as other materials 
specifically relevant to it, are contained in category X of Public 
Docket A-93-42, entitled ``Certification of Urban Bus Retrofit/Rebuild 
Equipment''. This docket is located at the address listed below.
    Today's notice initiates a 45-day period during which the Agency 
will accept written comments relevant to whether or not the equipment 
included in this notification of intent to certify should be certified. 
Comments should be provided in writing to Public Docket A-93-42, 
Category X, at the address below, and an identical copy should be 
submitted to William Rutledge, also at the address below.

DATES: Comments must be submitted on or before January 29, 1996.

ADDRESSES: Submit identical copies of comments to each of the two 
following addresses: 1. U.S. Environmental Protection Agency, Public 
Docket A-93-42 (Category X), Room M-1500, 401 M Street S.W., 
Washington, DC 20460.
    2. William Rutledge, Engine Compliance Group, Engine Programs and 
Compliance Division (6403J), 401 ``M'' Street S.W., Washington, DC 
20460.
    The TRT notification of intent to certify, as well as other 
materials specifically relevant to it, are contained in the public 
docket indicated above. Docket items may be inspected from 8:00 a.m. 
until 5:30 p.m., Monday through Friday. As provided in 40 CFR Part 2, a 
reasonable fee may be charged by the Agency for copying docket 
materials.

FOR FURTHER INFORMATION CONTACT: William Rutledge, Engine Programs and 
Compliance Division (6403J), U.S. Environmental Protection Agency, 401 
M Street S.W., Washington, DC 20460. Telephone: (202) 233-9297.

SUPPLEMENTARY INFORMATION:

I. Background

    On April 21, 1993, the Agency published final Retrofit/Rebuild 
Requirements for 1993 and Earlier Model Year Urban Buses (58 FR 21359). 
The retrofit/rebuild program is intended 

[[Page 64052]]
to reduce the ambient levels of particulate matter (PM) in urban areas 
and is limited to 1993 and earlier model year (MY) urban buses 
operating in metropolitan areas with 1980 populations of 750,000 or 
more, whose engines are rebuilt or replaced after January 1, 1995. 
Operators of the affected buses are required to choose between two 
compliance options: Program 1 establishes PM emissions requirements for 
each urban bus engine in an operator's fleet which is rebuilt or 
replaced. Program 2 is a fleet averaging program that establishes 
specific annual target levels for average PM emissions from urban buses 
in an operator's fleet.
    A key aspect of the program is the certification of retrofit/
rebuild equipment. To meet either of the two compliance options, 
operators of the affected buses must use equipment which has been 
certified by the Agency. Emissions requirements under either of the two 
compliance programs depend on the availability of retrofit/rebuild 
equipment certified for each engine model. To be used for program 1, 
equipment must be certified as meeting a 0.10 g/bhp-hr PM standard or 
as achieving a 25 percent reduction in PM. Equipment used for Program 2 
must be certified as providing some level of PM reduction that would in 
turn be claimed by urban bus operators when calculating their average 
fleet PM levels attained under the program. For program 1, information 
on life cycle costs must be submitted in the notification of intent to 
certify in order for certification of the equipment to initiate (or 
trigger) program requirements. To trigger program requirements, the 
certifier must guarantee that the equipment will be available to all 
affected operators for a life cycle cost of $7,940 or less at the 0.10 
g/bhp-hr PM level, or for a life cycle cost of $2,000 or less for the 
25 percent or greater reduction in PM. Both of these values are based 
on 1992 dollars.
    As noted above, operators of affected buses must use equipment 
which has been certified by EPA. An important element of the 
certification process is input from the public based on review of 
notifications of intent to certify. It is expected that engine 
manufacturers, bus manufacturers, transit operators, and industry 
associations will be able to provide valuable information related to 
the installation and use of particular equipment by transit operators. 
Such information will be useful to the Engine Programs and Compliance 
Division in its role of determining whether any specific equipment can 
be certified.

II. Notification Of Intent To Certify

    By a notification of intent to certify signed August 18, 1995, and 
subsequently modified by letter dated October 5, 1995, Twin Rivers 
Technologies, Limited Partnership (TRT), with principal place of 
business at 780 Washington Street, Quincy, Massachusetts 02169, applied 
for certification of equipment applicable to certain urban bus engines 
manufactured by Detroit Diesel Corporation (DDC). The notification 
states that the candidate equipment will provide reductions in exhaust 
PM, as discussed below, dependent upon the configuration used, from 
petroleum-fueled diesel engines that have been properly calibrated or 
rebuilt to the original engine manufacturer's specifications.
    TRT requests certification for the following two configurations of 
equipment: (1) Biodiesel fuel additive blended with diesel fuel (the 
blend is referred to as ``B20'') in combination with a particular 
exhaust system oxidation catalyst; and, (2) B20 and the catalyst, plus 
retarded fuel injection timing. Certification, if approved by the 
Agency, would apply to the combination of catalyst and biofuel supplied 
by TRT or its licensed distributors. The fuel B20 (alone) is not 
candidate for certification under this notification.
    One configuration of the candidate equipment, as applied to some 
engines, provides PM reductions greater than 25 percent and the other 
configuration does not. This is discussed further below. TRT has not 
provided life cycle cost information with the notification and has not 
requested to be certified as being available for less than the life 
cycle cost ceiling.
    A key component of both configurations of the candidate equipment 
is use of biodiesel as an additive at a 20 percent by volume blend 
ratio with diesel fuel. Biodiesel is an ester-based fuel oxygenate 
derived from biological sources for use in compression-ignition (that 
is ``diesel'') engines. Biodiesel is the alkyl ester product of the 
transesterification reaction of biological triglycerides, or 
biologically-derived oils. Any biological oil source, such as vegetable 
oils, animal fats or used cooking oils and fats, can produce esters 
through this reaction. TRT has registered biodiesel under the Agency's 
Fuel/Fuel Additive Registration Program, which defines Twin Rivers 
biodiesel (marketed as ``EnviroDiesel<SUP>TM'' and ``EnviroDiesel 
Plus<SUP>TM'') as an alkyl ester containing C1-C4 alcohols and C6-C24 
acids. The fuel handling procedure differs from that for diesel fuel 
only in that it requires mixing by the fuel distributor or bus operator 
of 20 percent by volume biodiesel with low-sulfur diesel fuel. TRT is a 
company created specifically for the production of biodiesel.
    A key component of both configurations of the candidate equipment 
is a particular oxidation catalyst-muffler unit (discussed further 
below) designed to replace the typical noise muffler in the exhaust 
system of applicable recipient engines. In a report included as an 
attachment to TRT's notification, it is indicated that the combination 
of B20 and the catalyst achieve greater PM reductions than with the 
catalyst alone. Improved PM reduction associated with that combination 
may be due to an apparent shift in the composition of total exhaust 
particulates, when using B20, toward a lower soot fraction and higher 
soluble organic fraction (SOF). It is the SOF portion of the exhaust 
particulates that an oxidation catalyst is most effective in reducing.
    The exhaust catalysts are to be matched to specific urban bus and 
engine configurations. Further, the maximum allowable exhaust pipe 
length between engine and catalyst is 108 inches. Exhaust system 
backpressure is designed to remain within the engine manufacturer's 
specified limits. The catalyst unit has no additional maintenance 
requirements for the life of the catalyst.
    The second configuration of the candidate equipment includes the 
retard of fuel injection timing in combination with B20 and the above-
described exhaust catalyst. All applicable engines using this second 
configuration and equipped with mechanical unit injection (MUI) would 
use a timing retard of four (4) degrees. All applicable engines using 
this configuration and equipped with electronically-controlled fuel 
injection would use a timing retard of one (1) degree. The notification 
states that timing is retarded by a shift of the timing sensor. The 
Agency requests comment and information concerning the reasonability of 
these timing specifications.
    For its certification testing, TRT used catalytic muffler units 
that were manufactured by Engelhard Corporation and are the same 
formulation and configuration that is certified by the Agency for use 
in the urban bus program (see 60 FR 28402, dated May 31, 1995, for that 
certification). While an agreement is in place for Engelhard to supply 
TRT with catalysts, the physical specifications of the catalyst to be 
used in production are neither part of the 

[[Page 64053]]
TRT notification of intent to certify nor provided to TRT as part of 
that agreement. In general, the Agency has concerns when a certifier is 
not aware of the technical specifications of equipment it wants to 
certify and when the potential exists for a change in equipment 
specifications to adversely affect emissions reduction performance. 
Such a change in specifications may occur, for example, with a change 
in catalyst production which may not be known to the certifier. In a 
letter provided to the Agency, Engelhard states that it will notify 
both TRT and the Agency in the event of changes to specifications of 
the catalytic converter muffler provided to TRT. The specifications for 
the catalyst have been provided to the Agency as a confidential part of 
Engelhard's notification of intent to certify its CMX<SUP>TM catalyst 
muffler. A copy of this letter can be found in the public docket at the 
address indicated above. This provides the Agency with assurance that 
changes to catalyst specifications will be brought to the Agency's 
attention, and the Agency proposes to restrict certification for 
candidate TRT equipment to use of catalyst muffler units supplied by 
Engelhard and covered by Engelhard's certification, and require that 
use of catalysts supplied by any other supplier be the subject of a 
separate notification of intent to certify.
    TRT presents exhaust emission data from testing the candidate 
equipment configurations on three engines using the federal engine-
dynamometer test procedures of 40 CFR Part 86, as well as chassis 
dynamometer testing. A 1977 model year DDC 6V71N and 1988 model year 
DDC 6V92TA DDEC II were tested on engine dynamometers, and another 1988 
model year DDC 6V92TA DDEC II was tested on a chassis dynamometer. The 
6V71N engine was selected to represent a ``worst case'', with respect 
to PM, for most of the engines for which certification of the equipment 
is being sought, and also to represent engines equipped with MUI. Based 
on a pre-rebuild PM level for the 6V71N of 0.50, from the table in 40 
CFR section 85.1403(c)(1)(iii)(A), TRT states that the 6V71N qualities 
as ``worst case'' for all two-stroke/cycle engines with the exception 
of the 1990 DDC 6L71TA. The 1988 6V92TA DDEC engines were tested to 
show the results of the biodiesel fuel on engines having electronic 
fuel control, and also to represent the ``worst case'' engine 
configuration for such engines, based on their ``pre-rebuild'' level of 
0.31 g/bhp-hr. The notification states that the fuel used for testing, 
both the biodiesel and diesel, are representative of commercially 
available biodiesel and low-sulfur diesel fuels.
    Baseline testing was conducted after two of the test engines were 
rebuilt to the original engine manufacturer's configurations. A third 
engine had not been used prior to testing. Baseline testing was 
conducted using low sulfur test fuel having a maximum sulfur level of 
0.05 weight percent. Subsequent testing of the engines was done after 
the candidate equipment was installed.
    Table 1A below summarizes the emission levels from the engine 
dynamometer testing. Table 1B summarizes the chassis testing in terms 
of range of impact on exhaust emissions of the candidate equipment from 
three driving cycles. The driving cycles used for the chassis testing 
were the Central Business District, New York Bus Composite Cycle, and 
the Arterial Cycle. A report attached to TRT's notification provides 
specific emission rates measured for each driving cycle and equipment 
configuration. Table 2 summarizes, for each test engine, the changes in 
PM and NO<INF>X emissions with use of each configuration of the 
equipment. The reductions listed for the chassis testing include double 
weighting of the emission data from the Arterial Cycle, because TRT 
believes the resultant combination of the chassis driving cycles is 
more representative of the Agency's Urban Dynamometer Driving Schedule 
for Heavy-Duty Vehicles (40 CFR Part 86, Appendix I). Table 3 provides 
a summary of all engine models for which TRT intends the equipment to 
apply, and the associated percent reductions in PM emissions for these 
models, based on the test data. Table 4 summarizes the PM certification 
levels for each engine model for which certification is sought, based 
on reductions of Table 3 applied to the pre-rebuild levels established 
in the program regulations. Additional testing information is provided 
in reports from the facilities which conducted the emission testing 
(these reports are attachments to the notification).

                                                            Table 1A.--Test Engine Emissions                                                            
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                    Gaseous and Particulate                 Smoke                                                       
                   Engine                    ---------------------------------------------------------------                   Comment                  
                                                 HC       CO      NO<INF>X       PM      ACC      LUG      Peak                                              
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                                        
(3) g/bhp-hr                                                                                                                                            
(2) percent opacity                                                                                                                                     
Engine Dyno.................................      1.3     15.5     10.7     0.60       20       15       50  1988 EPA stds.                             
1977 6V71N MUI..............................     0.86     3.18    11.72    0.282      1.2      1.8      1.8  Baseline (low S, 2D).                      
1977 6V71N MU...............................     0.38     0.86    12.11    0.166      0.9      1.7      1.7  B20 + cat.                                 
1977 6V71N MU...............................     0.42     0.94     8.47    0.213      2.2      2.8      2.9  B20, cat + 4 deg. retard.                  
1988 6V92TA DDEC II.........................     0.60     1.60     8.52     0.20      6.0      5.3      8.7  Baseline (low S, 2D).                      
1988 6V92TA DDEC II.........................     0.21     0.95     9.12     0.11      3.7      1.7      6.9  B20 + cat.                                 
1988 6V92TA DDEC II.........................     0.25     1.05     8.35     0.12      5.1      2.5        8  B20, cat + 1 deg. retard.                  
--------------------------------------------------------------------------------------------------------------------------------------------------------


    Table 1B.--Chassis Testing: Range of Percentage Change \1\ in Emissions From Baseline (Low Sulfur Diesel)   
----------------------------------------------------------------------------------------------------------------
               Pollutant                       B20 + catalyst              B20 + catalyst + 1.5 deg. retard     
----------------------------------------------------------------------------------------------------------------
HC.....................................  -59 to -39................  -33 to +3                                  
CO.....................................  -85 to -54................  -38 to -19                                 
NO<INF>X....................................  +4 to +8..................  -5 to -2                                   
PM.....................................  -56 to -22................  -46 to -7                                  
----------------------------------------------------------------------------------------------------------------
\1\ Three different chassis driving cycles were used.                                                           


                                                                                                                

[[Page 64054]]
                                  Table 2.--Emissions Changes From Test Engines                                 
----------------------------------------------------------------------------------------------------------------
                                               Configuration                          Per cent                  
           Test Engine           ----------------------------------------  Per cent     No<INF>X         Test/dyno   
                                      B20         CAT      Timing retard  PM change    change                   
----------------------------------------------------------------------------------------------------------------
1977 6V71N......................  <radical>   <radical>   None..........        -41         +3  Engine.         
MUI.............................  <radical>   <radical>   4 deg.........      -24.5        -28  ................
1988 6V92TA DDEC................  <radical>   <radical>   None..........        -45         +6  Engine.         
II..............................  <radical>   <radical>   1 deg.........        -40         -2  ................
1988 6V92TA DDEC................  <radical>   <radical>   None..........        -40         +4  Chassis.        
II..............................  <radical>   <radical>   1.5 deg.......        -27         -5  ................
----------------------------------------------------------------------------------------------------------------



              Table 3.--Applicable Engines and PM Reduction             
------------------------------------------------------------------------
                                                  Configuration and per 
                                                    Cent PM Reduction   
           Engine model             Model year -------------------------
                                                              B20, cat +
                                                 B20 + cat      retard  
------------------------------------------------------------------------
6V92TA MUI.......................        79-87         41.1         24.5
6V92TA MUI.......................        88-89         41.1         24.5
6V92TA DDEC I....................        86-87         45.0         40.0
6V92TA DDEC II...................        88-91         45.0         40.0
6V92TA DDEC II...................        92-93         45.0         40.0
6V71N MUI........................        73-87         41.1         24.5
6V71N MUI........................        88-89         41.1         24.5
6V71T MUI........................        85-86         41.1         24.5
8V71N MUI........................        73-84         41.1         24.5
6L71TA MUI.......................           90         41.1         24.5
6L71TA MUI.......................        88-89         41.1         24.5
6L71TA DDEC......................        90-91         45.0         40.0
------------------------------------------------------------------------


                    Table 4.--PM Certification Levels                   
------------------------------------------------------------------------
                                                 Equipment Configuration
                                               -------------------------
           Engine model             Model year                B20, cat +
                                                 B20 + cat      retard  
------------------------------------------------------------------------
6V92TA MUI.......................        79-87         0.29         0.38
6V92TA MUI.......................        88-89         0.17         0.23
6V92TA DDEC I....................        86-87         0.17         0.18
6V92TA DDEC II...................        88-91         0.17         0.19
6V92TA DDEC II...................        92-93         0.14         0.15
6V71N MUI........................        73-87         0.29         0.38
6V71N MUI........................        88-89         0.29         0.38
6V71T MUI........................        85-86         0.29         0.38
8V71N MUI........................        73-84         0.29         0.38
6L71TA MUI.......................           90         0.34         0.44
6L71TA MUI.......................        88-89         0.18         0.23
6L71TA DDEC......................        90-91         0.17         0.18
------------------------------------------------------------------------

    Section 85.1406(a) of the program regulations state ``The test 
results must demonstrate that the retrofit/rebuild equipment * * * will 
not cause the urban bus engine to fail to meet any applicable Federal 
emission requirements set for that engine in the applicable portions of 
40 CFR part 86 * * *''. TRT's emission test data indicate that both 
configurations of the candidate equipment reduce hydrocarbon (HC) and 
carbon monoxide (CO), when compared with baseline (pre-retrofit) 
emissions. There is, however, potential for concern with regard to 
NO<INF>X emissions from other engines with which the candidate 
equipment might be certified, because an increase of three percent was 
measured for the MUI test engine when equipped with the B20-catalyst 
configuration without fuel injection retard, and six percent for the 
electronically-timed DDEC II test engine. Because test data is not 
available on all engines for which certification of the equipment is 
sought, TRT performed analyses to determine whether such increases 
would indicate that other engines exceed applicable NO<INF>X standards. 
The analysis, in general, applies each of the measured increases to the 
NO<INF>X certification levels established by the engine manufacturer 
for engines tested under the Agency's new engine certification program. 
(New engine certification testing results are reported yearly by the 
Agency in its ``Federal Certification Test Results''.) Three percent 
increase in NO<INF>X is evaluated for engines equipped with MUI, and 
six percent increase is evaluated for engines equipped with 
electronically-timed injection. The increased NO<INF>X level is 
compared with the relevant standard for the particular engine. TRT's 
analyses is in the public docket, and discussed below. 

[[Page 64055]]

    TRT's analysis for MUI engines is broken down by engine model year 
to account for two new engine certification test procedures, each 
having particular emissions standards. The ``13 mode'' engine 
dynamometer test procedure was used for heavy-duty engine testing prior 
to the 1985 model year, and the ``transient'' engine dynamometer test 
procedure is used for 1985 and later model years. For certification 
under the urban bus program, TRT tested the 1977 model year 6V71N MUI 
engine using the ``transient'' procedure. While the ``13 mode'' test 
was used for new engine certification of the 1977 model year, the 
``transient'' test is the current standard test procedure for heavy-
duty engines and is generally recognized as more representative than 
the ``13-mode'' test. Therefore, the Agency believes that the NO<INF>X 
increase measured by TRT using the ``transient'' test data is a 
relevant gauge of the impact of the candidate equipment. TRT's analysis 
applies the increase to the new engine certification data available for 
engines of 1984 and earlier model years. Prior to 1985, there was no 
federal emission standard for NO<INF>X alone. The relevant emission 
standards (for engines that were certified using the ``13-mode'' 
procedure) are 16 g/bhp-hr for 1974 through 1978 model year engines and 
10 g/bhp-hr for 1979 through 1984 model year engines, for the sum of HC 
emissions added to NO<INF>X emissions. TRT's initial analysis applied 
three percent increase to the new engine certification levels for HC + 
NO<INF>X emissions for 1982 and later model year engines for which such 
data is available. This predicts that only one engine (a 325 horsepower 
version of 1982 model year 6V92TA engine family CGM0552FWG5) would 
exceed its NO<INF>X standard. Further analysis for this engine, 
applying three percent increase in its NO<INF>X emission level added to 
50 percent decrease in its reported HC certification level, indicates 
that the combined federal emission standard would not be exceeded for 
this engine if equipped with the candidate equipment. Based on this 
analysis and TRT's emission test data indicating significant reductions 
in HC emissions (at least 50 percent), the Agency believes that for any 
applicable pre-1985 engine equipped with MUI, an increase in NO<INF>X 
emissions of the percentage measured on the 1977 6V71N MUI test engine 
will be more than offset by a decrease in HC emissions, such that the 
HC + NO<INF>X standard will not be exceeded.
    Another part of TRT's analysis pertains to engines equipped with 
MUI and certified using the ``transient'' test procedure (that is, the 
engines of model year 1985 and later). TRT's analysis, applying three 
percent increase to NO<INF>X levels developed during new engine 
certification testing, indicates that no 1985 or later engine equipped 
with MUI would exceed the applicable federal standard if equipped with 
the candidate equipment. TRT also analyzed the impact of six percent 
increase in NO<INF>X emissions on electronically-controlled engines, 
because their data show that NO<INF>X emissions for the 1988 model year 
6V92TA DDEC II test engine increase roughly six percent when equipped 
with the B20-catalyst configuration without injection retard. This 
increase in NO<INF>X emissions is important, especially because federal 
standards for NO<INF>X were lowered to 6.0 g/bhp-hr for the 1990 model 
year and 5.0 g/bhp-hr for the 1991 model year. Therefore, TRT analyzed 
the impact of six percent increase in NO<INF>X emission levels 
developed during new-engine certification testing on Detroit Diesel 
Corporation's DDEC engines. (Under the new engine certification 
program, all DDEC engines have been tested using the ``transient'' 
procedure.) The results indicate that NO<INF>X levels for the engine 
families in Table 5 would exceed the appropriate federal emission 
standard. Therefore, the Agency proposes that use of the candidate 
equipment without fuel injection retard on any urban bus engines of the 
engine families listed in Table 5 not be covered by certification under 
the urban bus program.

         Table 5.--Engine Families not Covered by Certification         
------------------------------------------------------------------------
       Configuration: B20 and Catalyst (without injection retard)       
-------------------------------------------------------------------------
         Model year                   Model             Engine family   
------------------------------------------------------------------------
1990........................  6V92TA DDEC II......  LDD0552FZG6         
                              6V92TA DDEC II Coach  LDD0552FZL2         
1991........................  6L71TA DDEC ALCC....  MDD0426FZFX         
                              6V92TA DDEC II......  MDD0552FZG5         
                              6V92TA DDEC II......  MDD0552FZL1         
1992........................  6V92TA DDEC II......  NDD0552FZG4         
                              6V92TA DDEC II Coach  NDD0552FZL0         
1993........................  6V92TA DDEC II......  PDD0552FZG2         
                              6V92TA DDEC II Coach  PDD0552FZL9         
------------------------------------------------------------------------

    The Agency requests comment, additional analysis, or additional 
emission test data or for engine families to which the equipment is 
intended to apply, to determine whether regulatory requirements are met 
with urban bus engines using the candidate equipment.
    While absolute smoke opacity levels during testing of the 1977 
6V71N MUI test engine were well below relevant standards, increases 
were measured between the baseline test and testing using B20, catalyst 
and retarded timing. This is not of significant concern because the 
Agency believes the absolute level of increase is more relevant than 
the percentage increase. Further, the absolute level of increase in 
opacity is believed not significant in the context of the current smoke 
test and opacity standards (in other words, there is probably no real 
increase in smoke opacity, given the nature of the smoke test and level 
of the standards). Finally, smoke emissions from heavy duty diesel 
engines, in general, have declined over the years as engines are 
designed to comply with declining federal PM emissions standards. The 
Agency believes that even if this test data accurately predicts an 
increase in smoke emission opacity with other engines for which the 
equipment is intended to apply, it is not a significant increase. The 
Agency requests comment regarding the applicability of that data to 
other engines having MUI for which the equipment is intended to apply.
    Smoke emission measurements for the 1988 engine indicate compliance 
with applicable standards.
    As indicated in the notification, the 6V71N test engine qualities 
as a ``worst case'' for all two-stroke/cycle engines with exception of 
the 1990 DDC 

[[Page 64056]]
6L71TA. (The 1990 model year DDC 6L71TA has a pre-rebuild PM level of 
0.59 g/bhp-hr.) While TRT requests certification coverage for the 1990 
DDC 6L71TA and warrants comparable particulate emissions reduction 
percentages for it as is demonstrated by the 6V71N test engine, the 
requirement of the program regulations have not been met. Therefore, 
the Agency believes that the notification lacks sufficient basis for 
certification of the candidate equipment with the 1990 DDC 6L71TA.
    Section 85.1406(d) of the regulations governing urban bus equipment 
certification states, in part, ``* * * installation of any certified 
retrofit/rebuild equipment shall not cause or contribute to an 
unreasonable risk to the public health, welfare or safety * * *''. 
Information for considering whether B20 in this context would affect 
any potential human health risks associated with exposure to 
conventional diesel emissions has been provided by TRT with its 
notification of intent to certify. This information will be reviewed by 
the Agency. The Agency has made this information part of the public 
docket at the address listed above. Any findings based on this 
information, together with any other information that may be 
considered, will be made part of the public docket located at the 
address noted above, and considered by the Agency in its decision 
regarding certification of the candidate equipment. The Agency requests 
additional information, including information on combustion by-
products, for considering whether and, if so how, the use of the 
subject biodiesel blend, that is, B20, in diesel engines would affect 
any potential health risks associated with exposure to conventional 
diesel emissions.
    Section 211 of the Clean Air Act sets forth fuel and fuel additive 
prohibitions, and gives the Agency authority to waive certain of those 
prohibitions. The Agency, however, does not believe that TRT must 
obtain a fuel additive waiver under Section 211(f)(4) of the Clean Air 
Act before certifying its additive system for the following reasons.
    The Act prohibits the introduction into commerce of any fuel or 
fuel additive that is not substantially similar to a fuel or fuel 
additive used in the certification of any model year 1975 or later 
vehicle or engine under Section 206. The Administrator may waive this 
prohibition, if she determines that certain criteria are met. The 
Agency believes that certification of an urban bus retrofit system 
constitutes the certification of an engine under Section 206 for the 
purposes of the urban bus retrofit/rebuild program, and, since the 
additive is used in the certification of the system, a waiver is not 
required to market the additive in the limited context of use with the 
certified retrofit system. This determination does not affect whether 
the additive is ``substantially similar to any fuel or fuel additive'' 
outside the context of the urban bus retrofit/rebuild program. The 
Agency's position on this matter is discussed in additional detail as 
it relates to use of another fuel additive (Lubrizol Corporation) at 60 
FR 36139 on July 13, 1995.
    If the Agency certifies the candidate TRT equipment, operators may 
use it immediately, as discussed below. TRT's notification indicates 
that the candidate equipment is to be certified for compliance program 
2; however, as discussed below, the Agency believes that configurations 
utilizing the catalytic muffler and reducing PM by at least 25 percent 
may also be used in compliance with current program 1 requirements.
    In a Federal Register notice dated May 31, 1995 (60 FR 28402), the 
Agency certified an exhaust catalyst manufactured by the Engelhard 
Corporation, as a trigger of program requirements. For urban bus 
operators affected by this program and electing to comply with program 
1 requirements, that certification means that rebuilds and replacements 
of all applicable urban bus engines, performed 6 months or more after 
that date of certification (that is, rebuilds or replacements after 
December 1, 1995), must be performed with equipment certified to reduce 
PM emissions by 25 percent or more. Under Program 1, operators could 
use the TRT equipment if certified to reduce PM by at least 25 percent, 
or other equipment certified to provide at least a 25 percent 
reduction, until equipment is certified which triggers the 0.10 g/bhp-
hr PM standard. For Program 1, operators may also use the B20 blend 
with the Engelhard catalyst and injection retard only for the following 
engines: 6V92TA DDEC I and DDEC II, and 6L71TA DDEC.
    Operators who choose to comply with Program 2 and install the TRT 
equipment, would use the PM emission level(s) established during the 
certification process, in their calculations for target or fleet level 
as specified in the program regulations.
    In accordance with the program requirements of section 85.1404(a), 
operators using the candidate equipment would have to maintain purchase 
records of the B20 blend if the operator purchases the premixed blend 
from a fuel supplier, or, of biodiesel and low-sulfur diesel fuel if 
the operator mixes the B20. Such records would be subject to review in 
the event of an audit of a urban bus operator by the Agency. To be in 
compliance with program requirements, operators must be able to 
demonstrate that B20 is being used in the proper proportions required 
by the candidate equipment.
    At a minimum, EPA expects to evaluate this notification of intent 
to certify, and other materials submitted as applicable, to determine 
whether there is adequate demonstration of compliance with: (1) The 
certification requirements of Sec. 85.1406, including whether the 
testing accurately substantiates the claimed emission reduction or 
emission levels; and, (2) the requirements of Sec. 85.1407 for a 
notification of intent to certify.
    The Agency requests that those commenting also consider these 
regulatory requirements, plus provide comments on any experience or 
knowledge concerning: (a) problems with installing, maintaining, and/or 
using the candidate equipment on applicable engines; and, (b) whether 
the equipment is compatible with affected vehicles.
    The date of this notice initiates a 45-day period during which the 
Agency will accept written comments relevant to whether or not the 
equipment described in the TRT notification of intent to certify should 
be certified pursuant to the urban bus retrofit/rebuild regulations. 
Interested parties are encouraged to review the notification of intent 
to certify and provide comment during the 45-day period. Please send 
separate copies of your comments to each of the above two addresses.
    The Agency will review this notification of intent to certify, 
along with comments received from interested parties, and attempt to 
resolve or clarify issues as necessary. During the review process, the 
Agency may add additional documents to the docket as a result of the 
review process. These documents will also be available for public 
review and comment within the 45-day period.

    Dated: December 1, 1995.
Mary D. Nichols,
Assistant Administrator for Air and Radiation.
[FR Doc. 95-30405 Filed 12-12-95; 8:45 am]
BILLING CODE 6560-50-P