P.1 

OAR Box 1846 

Prepped by Ollie Stewart 

Document Number: 

50) ll-F-4 

Docket Number: 

A-90-07 

Printed 11/18/2008 7:30:16 AM Sheet 50 of 93 
T 

• v MAR J 8 1992-A H •f~04 

P.2 

NOTE 

TO: Troy Hillier, OMB 

Rich Theroux, OMB 

RE: Transmittal of Changed NPRM Pages for the 

Fuels/Additives Program 

The NPRM changes we discussed at our March 12th meeting are 

reflected in the attached pages. To facilitate your review, the 

changed material is indicated by arrows in the left margin. Also, 

where a page number has changed in relation to the previous draft 

(dated 12/10/91), the corresponding page number in the earlier 

draft is shown in brackets in the lower right corner of the new 

page. 

Most of the new material related to the interpretation of 

negative test results and to criteria which would indicate that 

Tier 3 will not be necessary can be found on (new) pages 191-200. 

Please give me a call (374-8231) if any questions arise. As 

you know, our time is extremely short and I look forward to 

receiving your comments and/or concurrence by tomorrow. 

Thank you, 
P.3 

this may be appropriate for defining baseline formulations in 

this proposed program. However, EPA is also considering 

restricting baseline formulations to those with less than 1.5 

weight percent of oxygen. In the latter case, "reformulated" 

fuels would be excluded from the "baseline" classification. 

This would result in the generation of more explicit 

information for various oxygenated gasoline fuels. 

4. Health Effects Testing Provisions 

A number of respondents argued that an overly stringent 

and expensive health effects testing program would be counter 

to the public interest. They pointed out that unreasonably 

high costs of program compliance would discourage the 

development of new fuels and additives and would reduce the 

availability of products potentially beneficial to the public 

-» health and welfare. While the testing program must provide 

—» adequate information for assessing the toxicity of fuels and 

—» additives, EPA is well aware of the importance of striking an 

-» appropriate balance between scientific demands and technical 

—> and financial constraints, taking into account both the need 

—» for adequate information and the need for continued 

—> innovation. The Agency believes that the program outlined in 

the proposed rulemaking is consistent with the statute and 

reflects a reasonable and cost-conscious approach to a very 

complex regulatory area. 

23 
P.4 

EPA does not agree, however, that the manufacturer of an 

additive should be relieved of registration responsibilities 

just because of the additive's similarity to its parent fuel. 

Instead, provisions within the proposed grouping system should 

be able to account for these relationships. Such mechanisms 

are discussed further in Section IV, below. 

5. Small Business Provisions 

Under section 211(e), EPA is authorized to create special 

program allowances and/or exemptions which would reduce the 

burdens of program compliance for small businesses. If EPA 

should choose to exercise this authority, the operative 

definition of a small business would be specified within the 

associated regulations. Respondents who commented on this 

matter felt that any small business definition would be 

arbitrary and unfair. In their view, small business 

provisions could potentially place individual manufacturers 

who sold multiple low-volume products at a disadvantage 

relative to single-product manufacturers. They also believed 

that the rules governing small business allowances could be 

manipulated by large manufacturers, creating loopholes never 

intended by EPA. 

—> While EPA does not necessarily share each of the 

—> respondents' concerns, this NPRM does not contain specific 

—» proposed provisions for small businesses. In general, the 

—> proposed grouping scheme, tiered testing structure, and other 

27 
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—»general provisions should assure that undue burdens are not 

—»placed upon small businesses. Nevertheless, EPA's analysis 

—> indicates that the costs of compliance with the proposed 

-» program may place a few small businesses in financial 

—> jeopardy. EPA is thus attempting to identify the 

—» characteristics which may make some small companies unusually 

—» vulnerable to the potential financial impact of the proposed 

—> requirements, and to specify fair and appropriate approaches 

—> for providing cost relief to such companies. These topics are 

—» discussed further in Section VIII.C. 

E. Key Terms 

A fuel is defined to be any material which is capable of 

releasing energy or power by combustion or other chemical or 

physical reaction. Only fuels intended for use in motor 

vehicles are included under the proposed regulations. 

Currently, fuels intended for use exclusively in off-road 

vehicles are not designated for registration. Both domestic 

and foreign products are included in the designation. 

A fuel additive is any substance that is intentionally 

added to a fuel and that is not intentionally removed prior to 

sale or use. Bulk additives are products which are added to 

fuel before the fuel is commercially available for 

introduction into the fuel tank of a motor vehicle, whether 

added at the refinery as part of the original blending stream 

28 c-a 
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all such products to undergo emission control system testing 

years after their initial registration and commercial 

distribution. 

Such evidence of adverse emission control effects may 

come to light as a result of emission characterization 

requirements included within the health effects testing 

provisions of today's proposed rulemaking. The proposed 

emission characterization requirements include Federal testing 

procedures to determine the levels of regulated emissions 

generated by the fuel/additive of interest. Should any of the 

regulated emission products exceed established certification 

standards, a need for examination of the product's effects on 

emission control may be indicated. 

EPA also proposes to set up a mechanism which would 

permit vehicle manufacturers or other outside parties to 

submit petitions to EPA, citing evidence that certain brands, 

—> formulations, or specific components of fuels or additives are 

—> harmful to vehicular emission control. If EPA judges that 

—¥ emission control system testing is warranted after reviewing 

the petition arguments, emission characterization results, 

and/or other available information, the authority provided by 

section 211(b) will be exercised to bring specified fuels and 

additives into the waiver application program when they would 

otherwise be excused by the "grandfathering" provisions of 

section 211(f). 

46 
P.7 

EPA requests comments on the adequacy of this proposed 

approach. As an alternative, the authority of section 211(b) 

could be exercised to require all "grandfathered" products to 

undergo waiver request procedures under Section 211(f) if they 

do not conform to applicable "sub sim" criteria. Comments are 

-> solicited in regard to the specific necessity and the likely 

—> costs and benefits of this more comprehensive approach in 

comparison to the mechanism described above. 

E. Scope of Health Effects Evaluation 

1. Background 

Registration requirements concerning the health effects 

of fuels and fuel additives could potentially encompass a vast 

range of endpoints, exposure scenarios, mechanisms of action, 

—> and experimental protocols. Taking into account the number of 

-» fuels and additives in question, a comprehensive toxicologic 

—> program could easily overwhelm the capacity of existing 

—> laboratory facilities and support systems, and the total costs 

—> of such a program would be very likely to exceed its expected 

-> benefits. Over 6,000 fuels and additives are currently 

registered, and this population is expected to undergo further 

growth in the near future as reformulated and alternative 

fuels and their additives gain a wider role in the 

marketplace. 

47 N^l 
P.8 

studies on the individual emission products of the fuel or 

additive would not adequately substitute for whole emissions, 

unless emission characterization studies showed that an 

additive has only one emission product that differentiates its 

emissions from the base fuel. Documentation would need to be 

sufficient to determine that the studies were conducted in a 

manner consistent with generally accepted scientific 

principles, good laboratory practices, and the specific 

testing guideline in question. Important parameters would 

include the type and number of test subjects, the number and 

adequacy of dosages, the methodology and duration of 

inhalation exposure, and the technical methods used for 

monitoring the progress of the test and for analyzing the 

results. In general, the exposure duration would need to be at 

least as long as that stipulated in the specified Tier 2 

guideline; however, shorter exposures would be acceptable if 

the test results were positive, including a demonstrable dose-

-» response relationship. Finally, the age of the data would be 

—> a consideration. In view of technological advances and 

—» changing technical standards, older studies would be less 

—» likely to be acceptable than more recent studies. 

Nevertheless, the quality of the study would be the deciding 

factor, not the age per se. These same considerations would 

later be used by EPA in judging whether the submitted tests 

were in compliance with the program requirements. 

57 
P.9 

Tier 2 tests are negative (i.e., apparently non-toxic), if EPA 

judged that inadequate laboratory procedures or techniques 

interfered with the test results. 

While the specific objectives and scope of Tier 3 testing 

would vary depending on the concerns identified in the earlier 

tiers, chronic (2-3 year) inhalation studies would sometimes 

be included. Chemical disposition studies, exposure studies, 

and dosimetry analyses as well as additional emission 

characterization requirements might also be imposed. These 

requirements would most often be intended as follow-up to 

studies included in Tier 2. However, EPA reserves the general 

authority to require the evaluation of other endpoints if 

available information indicates that this is necessary for 

regulatory decision-making. For example, if the literature 

search suggests that the emissions of a fuel or additive are 

toxic to the liver or kidneys, then EPA would not be precluded 

from imposing hepatotoxicity or renotoxicity testing 

requirements under Tier 3 simply because screening studies for 

these endpoints were not included under Tier 2. 

—» Section VI of this NPRM presents further discussion on 

—> the circumstances which would lead EPA to conclude that Tiers 

—> 1 and 2 provide sufficient information without invoking Tier 

—> 3, the potential criteria for imposing Tier 3 testing 

—» requirements, and the likely nature of such requirements. 

61 
P.10 

3 issues within the context of the registration program. One 

alternative is to retain the option of imposing welfare 

effects testing requirements at the Tier 3 level when the 

outcome of Tier 1 demonstrates both significant environmental 

M —»toxicity and exposure potential. The criteria for such 

Q_ —» decisions would be similar to those used for making health5 -» related Tier 3 decisions. Thus, Tier 3 testing for welfare 

^ effects might be required if the environmental partitioning 

> and exposure analysis reveals the potential for broad exposure 

/* 

at concentrations that are likely to pose a threat to 

sensitive plants and animals. 

If this alternative were adopted, Tier 3 welfare effects 

testing would be determined by EPA on a case-by-case basis. 

Numerous protocols are available. Endpoints of concern for 

aquatic, mammalian, and avian toxicology might include, but 

are not necessarily limited to, lethal concentrations, effects 

on growth and reproduction, and bioaccumulation. Plant 

toxicological endpoints might include growth, yield, 

reproduction, fruit quality, and tissue damage or loss. The 

exposure treatments for such tests would be administered at 

expected environmental concentrations. 

Specific Tier 3 test requirements would be tailored to 

evaluate the potential environmental problems identified in 

Tier 1. For example, if the Tier 1 modeling results indicated 

that toxic emissions partitioned to air or soil and posed a 

68 
P.11 

As noted above, a fuel family has been defined for leaded 

gasoline and associated additives. However, provisions in the 

1990 Amendments to the Clean Air Act prohibit the manufacture 

or sale of new leaded-fueled motor vehicle engines beginning 

with model year 1993, and ban the sale of leaded fuels for onroad use as of January 1, 1996. Thus, leaded fuels and 

additives will be phased out at about the same time that data 

would be submitted under today's proposed rule. In view of 

the upcoming constraints on leaded products and the timing of 

the new registration program's implementation, comment is 

requested about the need to include these products in the 

grouping system or, indeed, in the new registration program 

itself. 

Consistent with the previous discussion on fuel-additive 

relationships, each fuel family includes not only the fuels 

referenced in the name of the family, but also bulk and 

aftermarket additives which are intended for use in such 

fuels. Additives which can be used in conjunction with more 

than one type of fuel are proposed to be assigned to the 

relevant fuel family of which the most gallons of fuel are 

sold relative to the other applicable fuel families. An 

alternative approach would require such additives to be tested 

—» in association with all relevant fuel families. Comment is 

—¥ requested on this alternative, including the expected costs 

—>and benefits relative to the proposed approach. 

80 
P.12 

Inert gases, principally C02 and N2, could comprise up to 5 

mole percent of the fuel and "other hydrocarbons" could make 

up a further 3.5 mole percent. 

•^ Liquified petroleum gas (LPG), or propane gas, would be 

j\ required to contain, at a minimum, 80 percent propane by 

c 

i 

volume. CARB proposes that it also contain a maximum of 10 

volume percent propene, while ASTM supports a maximum of 5 

volume percent. The limit for butane and other hydrocarbons 

is proposed to be 2.5 volume percent and the sulfur content is 

—» restricted to 123 ppmw. 

Comments and suggestions are requested regarding the most 

appropriate criteria for distinguishing the baseline, nonbaseline, and atypical categories within the alternative fuel 

families. As EPA acquires additional data on alternative fuel 

and additive formulations, this information will be placed in 

the docket and made available for public inspection. 

Groups. The fuel/additive groups are subdivisions of the 

fuel/additive categories, and represent the final level of 

product classification within the grouping system. These 

groups are the actual operating units of the grouping system. 

Within each group, one or more formulations will be chosen to 

represent all of the member products in compliance with the 

registration program's testing requirements. Related costs 

will be shared by participating blenders and manufacturers. 

93 
P.13 

unleaded gasoline groups and 47 "atypical" diesel groups. 

Comments are requested concerning this proposed grouping 

—» scheme and possible alternative approaches. For example, 

—> comment is requested on the necessity of establishing separate 

—» groups for each unique combination of "atypical" elements and 

—> conditions, as is proposed. Alternatively, it might be 

—> possible to define some reasonable rules of precedence which 

—» would allow products containing certain combinations of 

-» "atypical" characteristics to be grouped with products 

—> containing only one of these characteristics. Such an 

—» approach would decrease the total number of groupings and 

—» would increase the number of potential products in each group. 

Suggestions are also welcome in regard to additional variables 

(e.g., aromatic content or the presence of specific oxygenate 

compounds) which should be taken into account in defining 

groups of atypical products, recognizing that each new factor 

could increase the number and decrease the size of the 

resulting groups. 

For each group, the representative to be used in 

satisfying the group's testing requirements is proposed to be 

the member product with the highest concentration of atypical 

elements. In case of ties, a process for selecting the 

representative is proposed which would give precedence to the 

relevant characteristics in the following priority order: 1) 

total metals, 2) total halogens, 3) total of other atypical 

elements, 4) total oxygen content, 5) polymer content. 

100 
P.14 

-» EPA has proposed that the representative be selected to 

—> reflect the highest concentration of atypical elements so 

—» that, if subsequent tests are negative, these results can 

—> safely be generalized to all group members. If, instead, the 

—>representative were chosen to reflect the average or median 

—>concentration of atypical elements among products in the 

—>group, the significance of negative test results would be 

-¥ unclear for group members with higher concentrations of 

—> atypical characteristics. In case a particular group contains 

—> products which generally reflect a distinct clustering of 

—> concentrations plus one or more products with much higher 

—> concentrations, the associated manufacturers may choose to 

—> divide the group on this basis to prevent a distant "outlier" 

—» from serving as the representative for all. 

d) Groups within the Baseline "Alternative" Categories 

Within the baseline methanol category, EPA proposes to 

establish two fuel/additive groups. One group would include 

MlOO formulations (containing at least 96% methanol) and would 

be represented by a designated MlOO base fuel formulation. 

The second group would consist of methanol/gasoline blends 

containing 50-96% methanol. The latter group would be 

represented by a designated M85 base fuel, reflecting the 

expected preponderance of end-use formulations in this group. 

Because EPA has little experience with formulations in 

the ethanol, methane, and propane fuel families, suggestions 

101 M 
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requirements, including both the Tier 1 requirements for 

chemical speciation of emissions and the biological testing 

requirements of Tiers 2 and 3. An alternative approach would 

require all unique fuel and additive formulations to undergo 

emission characterization independently, applying the group 

representative principle only in regard to biological testing 

requirements. This approach would provide more definitive 

information on the emission products of each fuel and 

additive, but would increase program costs to individual 

manufacturers and would increase demands on scarce commercial 

—» laboratory capacity. EPA requests input from the public on 

—> the likely benefits and costs of imposing separate emission 

—» speciation requirements for each fuel and additive as compared 

—» to requiring the emissions data only for the designated group 

—» representative. 

C. Grouping System Implementation Issues 

The practical implementation of the grouping system 

involves two major tasks: the organization and administration 

of group functions, and the development of equitable 

arrangements for cost sharing. Backed by its experience with 

respect to the TSCA testing program, EPA believes that the 

fuel/additive industry, under the aegis of its various trade 

associations or other third parties, is capable of 

accomplishing these tasks with little or no Agency assistance 

and interference. However, effective operations will be 

critical to the overall success of the grouping provisions of 

104 Do0 
P.16 

laboratory animals to fuel/additive emissions. This section 

presents the methods proposed for generating, storing, and 

sampling the emissions to be used in these chemical and 

biological tests. With a few noted exceptions, emissions will 

be generated according to the Federal Test Procedure (FTP) for 

light-duty vehicles (40 CFR Part 86). 

A. Vehicle Requirements 

1. Vehicle Selection 

Because the composition of emissions produced by a given 

fuel or additive is likely to vary somewhat depending on the 

vehicle involved, a fully comprehensive testing program would 

need to encompass the emissions from many vehicles 

representing a complete cross section of the in-use fleet. In 

the context of the proposed Reformulated Gasoline Rulemaking, 

EPA suggested that to obtain a statistically significant set 

of emission characterization results encompassing the variety 

of emission control systems available, emissions would need to 

be generated from at least 20 vehicles for each fuel under 

evaluation (see Supplemental Notice of Proposed Rulemaking, 

available in Docket # A 91 02). For purposes of the routine 

registration of motor vehicle fuels and fuel additives, 

however, EPA believes that such an extensive emission sampling 

and testing scheme may not be reasonable or necessary. EPA is 

initially proposing that only one vehicle be required to 

generate the emissions to be used for the chemical and 

111 M 
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thereof, would be chosen to generate emissions for biological 

testing. 

Another possible variation in the proposal would allow 

in-use vehicles which have already accumulated sufficient 

mileage to be employed for generating emissions instead of 

requiring mileage accumulation on new vehicles. While this 

alternative would reduce compliance costs, it has some 

possible drawbacks. Long-term emission effects caused by the 

fuels and additives previously used in these vehicles could 

alter the generated emissions and therefore the emission 

characterization and biological test results. It would then 

be difficult to assess the extent to which the test fuel was 

responsible for the test results. Another drawback is the 

absence of information on the long-term effects of the test 

*2fc fuel or additive. Finally, gaming could occur such that 

i 

V ^. emission characterization could be performed on many vehicles 

11 

11 

and only the best results submitted. Comment is requested on 

whether in-use vehicles would be acceptable for this program. 

«• «i EPA has also identified an alternative emission 

v-' generation scenario which incorporates a number of the 

possible program modifications described above. Because this 

scenario would require the use of more vehicles in the testing 

program in order to increase the confidence that can be placed 

in the results, methods of reducing other associated costs 

have also been identified. 

117 fr€ 
P.18 

A third possibility for automation would involve the use 

of an isolated engine (in conjunction, perhaps, with the 

vehicle's fuel and emission control systems) attached to an 

engine dynamometer. Since the input parameters required for 

controlling engine dynamometers are different from the wheel 

speed driving trace of the chassis dynamometer, the light-duty 

Urban Dynamometer Driving Cycle would need to be translated to 

an equivalent load-speed pattern, or else an alternate driving 

cycle would be required. 

—» EPA is initially proposing to require the use of engine 

—> dynamometers to generate emissions for the heavy-duty class 

—> and chassis dynamometers to generate emissions from light-duty 

—> vehicles. In the heavy-duty case, use of an engine 

—> dynamometer for emission generation is consistent with all 

—> existing heavy duty emission testing programs and also 

-» provides considerable cost advantages. In contrast, in the 

—> light-duty case, existing emission testing programs require 

—» the use of a vehicle operated on a chassis dynamometer for 

—» emission generation. To use an engine dynamometer for this 

—> purpose, extensive testing would have to be done to 

—» demonstrate that the exhaust emissions were the same as those 

—> generated from the corresponding light-duty vehicle operated 

—> on a chassis dynamometer. Many technical problems would have 

—i* to be confronted in attempting to isolate the engine and 

—> emission control equipment from the vehicle while assuring 

—» that the representativeness of the emissions would be 

125 o<i 
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—> maintained. These would include decisions on which vehicle 

—» systems must remain attached to the engine and what methods to 

—> use to terminate unnecessary systems; the addition of a 

-» flywheel, harmonic balancer, and bell housing to balance the 

—> system for vehicles equipped with automatic transmissions; 

-> determination of the effect of detaching transmission sensors 

-» such as gear sensors, clutch lock/unlock sensors, and torque 

—» converter speed sensors; and the translation of the LA-4 

—» chassis dynamometer driving cycle to an operating cycle 

—> appropriate for use with an engine dynamometer. 

— > EPA believes that the putative cost savings associated 

—> with the use of a light-duty engine dynamometer rather than a 

—> light-duty vehicle and chassis dynamometer would be overridden 

—> by the costs associated with resolving these problems and 

—>performing tests to prove that the solutions were valid. 

—¥ However, EPA is open to comment on the relative costs and 

—» benefits of the light-duty chassis dynamometer vs. engine 

—> dynamometer, and would consider making the use of the engine 

—> dynamometer optional in this program if the comments provide 

—> persuasive evidence that this option would be advantageous. 

C. Evaporative Emission Generation 

As discussed above in Section III.C, the evaporative 

emissions of some fuels and additives will be required to 

undergo emission characterization and biological testing. The 

126 t!«3 
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additional mileage accumulation will be performed until the 

emissions of the atypical elements reach steady state. Steady 

state will be defined as the point at which the mass of the 

atypical elements emitted during the performance of one or 

more Urban Dynamometer Driving Schedules/Engine Dynamometer 

Schedules is within 10 percent of the mass of the atypical 

elements that entered the combustion chamber during the 

driving cycles. 

—» In determining whether steady state has been reached, 

—» some less obvious pathways for the loss or introduction of the 

—» atypical elements may need to be taken into account. For 

—> example, if the atypical compounds could be lost through 

—» evaporation, then the evaporative emissions would be speciated 

for these compounds. If the atypical element enters the motor 

oil via the combustion chamber, the concentration of the 

atypical element in the motor oil may be measured and entered 

into the mass balance. If there is reason to suspect that the 

air used during combustion or dilution may contain significant 

quantities of the atypical element under evaluation, this air 

must also be tested and the problem rectified. 

—» EPA is initially proposing that mileage accumulation be 

—> continued either until steady state of the atypical elements 

—> has been reached or until the vehicle or engine has been 

—> operated on the atypical fuel or additive for the equivalent 

—> of 80 percent of its estimated useful life (e.g., 80,000 miles 

134 H 
P.21 

—> for light-duty vehicles). The purpose of this rigorous 

—> requirement is to ensure that the emission products of the 

-» elements of concern are known and that their concentrations 

—» are stable when the emissions are used in subsequent testing. 

—» In actual use, however, few vehicles are likely to be driven 

—> continuously on "atypical" fuels and additives. The use of 

—» such products by consumers is more likely to be intermittent 

-» and/or limited to particular owners along the chain of 

—» individuals who may own a given vehicle. Thus, the proposed 

—> requirement for accumulating mileage up to 80 percent of a 

—»vehicle's or engine's useful life (unless steady state is 

—> reached at an earlier point) may far exceed the amount of 

—> mileage and the concentration of atypical emission products 

—»which would generally be encountered in actual use. If so, a 

—> lower mileage requirement, perhaps in the range of 25-50 

—» percent of the vehicle's useful life, may be more appropriate 

—» in pursuit of the steady state condition. Comments are 

—» requested on these issues and on appropriate mileage 

—> accumulation requirements. Data on typical consumer usage 

—» patterns for atypical products would be particularly helpful 

—» to this decision. If the comments are supportive of a change 

—» in the proposed requirements, EPA would expect to reduce the 

—> mileage accumulation required in the Final Rule for atypical 

—» fuels and additives to a mileage figure in the lower range 

—> mentioned above. 

135 C«G 
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3. Additive Concentration 

Prior to emission generation and testing, additives are 

to be mixed with their associated base fuel to a concentration 

equal to that recommended by the additive producer as the 

maximum in-use concentration. One alternative would require 

mixing of fuel additives in their base fuels at a 

significantly higher concentration than the recommended 

amount, i.e., to "dope" the mixture with the fuel additive. 

Another possible method of doping an additive/base fuel 

mixture would be to significantly increase the concentration 

of particular components of an additive product (e.g., the 

compounds that contain atypical elements). The primary 

purpose of these approaches would be to enhance the 

contribution of the additive product (or the particular 

component of concern) to the emissions produced by the 

additive/base fuel mixture. This would facilitate the task of 

detecting and analyzing the additive's emissions and 

distinguishing them from the emissions produced by the base 

fuel. It would also effectively increase the dosage of 

additive emissions during biological exposures to 

additive/base fuel emissions, increasing the likelihood that 

observable changes could be detected in comparison with 

exposures to emissions of the base fuel alone. EPA asks for 

comment on the mixing rules that should be adopted and on the 

validity of doping the base fuel with the fuel additive or 

active ingredient, and on appropriate concentration levels for 

doping. 
P.23 

addition to MTBE, but will require appropriate modifications 

for application to gas phase samples. 

e. PAH and NPAH Characterization 

PAH and NPAH are mutagenic compounds which have been 

designated as a topic for study by the Clean Air Act (Section 

202(1) (1)) to determine if their emission by motor vehicles 

should be regulated. PAH and NPAH are typically found in 

combustion emissions, and their identification in evaporative 

emissions will not be required under Tier 1 provisions. In 

the past, PAH and NPAH have been analyzed primarily in the 

particulate phase. However, evidence now suggests that the 

quantity of these compounds in the semi-volatile phase at the 

temperatures encountered in dilute exhaust may be important. 

For this reason, PAH and NPAH will be speciated in both semivolatile and particulate phase emissions. 

— ¥ At this time, EPA is proposing that these PAH and NPAH 

—» characterization requirements be applied to all organic-based 

-> fuels and additives. However, it has been argued that the 

—> combustion of low molecular weight fuels such as methane, 

—» propane, ethanol, and methanol will not generate PAH and NPAH 

—> in significant quantities if the vehicles that generate the 

—» emissions are in proper operating condition. Comments and 

—¥ supporting data are thus requested on the necessity of 

—> imposing PAH and NPAH characterization requirements for these 

—> fuels. 

152 l»& 
laboratories. The results of the round robin can determine 

the inherent procedural variation along with the quality of 

the labs performing the test. For example, if four labs 

obtained similar results for a known solution and one lab 

produced results that were significantly different, the 

reproducibility could be evaluated by the results of the four 

similar labs and the fifth lab could be excluded from further 

testing until the differences were resolved. 

EPA asks for comments on possible arrangements for 

participating labs to perform speciation protocols in the 

context of a round robin program in order to determine test 

reproducibility and identify those labs capable of performing 

the required protocols with sufficient accuracy. To this end, 

labs wishing to take part in the testing program could 

voluntarily test a vehicle's emissions or analyze an unknown 

sample provided by EPA. If the results were accurate, EPA 

would have some assurance that the data generated by the lab 

would be acceptable. 

c. Audits 

EPA will reserve the right to audit testing facilities 

involved in the generation and characterization of emissions 

. for purposes of fuel/additive registration so that the quality 

^ —> of results is assured. Such audits would be organized and 

^o —» administered by EPA at its own expense. The audit procedures 

could include a requirement that facilities submit a completed 

157 0*0 
P.25 

alternative approach. Rather than using mathematical models, 

a requirement could be established for analysis by a qualified 

chemist of the likely atmospheric fate of the emission species 

as a result of chemical reactions, deposition, and other 

processes. EPA would welcome comments from the public on the 

suitability of these or other approaches for estimating the 

atmospheric reactivity of fuel/additive emissions. 

— > An argument can be made that requirements for the 

-» modeling of atmospheric reactivity would lead to redundant 

—» efforts by many manufacturers, since considerable overlap 

—> would be expected in the emission products of different fuels 

—> and additives (or groups) . According to this argument, the 

—> duplicate efforts could be avoided if EPA itself were to run 

—» the models when needed, using the emission speciation data 

—> submitted by the fuel and additive manufacturers. Under this 

—» line of reasoning, once the data on primary emission products 

—> has been submitted, EPA would be in the best position to 

—» compare the emission profiles of different fuels and 

—» additives, and to use appropriate models to predict the 

—» implications for atmospheric reactivity. 

- > 

—> While this argument appears to have some validity, it 

—> also contains some drawbacks. First, different manufacturers' 

—>submissions would be received by EPA at different times, 

—> interfering with EPA's ability to compare the emission 

—>profiles of various fuels and additives. Such comparisons 

170 Dtsl 
P.26 

—»would be difficult to perform in any case, and it is likely 

-»that EPA's attention would be drawn to fuels or additives 

-»which appear to generate unusually high concentrations of 

-» known precursors to harmful transformation products. As a 

—» result, fuels and additives which might provide a relative 

—» advantage in terms of atmospheric reactivity would tend to be 

-» overlooked. Such favorable results could be important in the 

-»overall evaluation of a fuel or additive for which certain 

-» adverse effects were also demonstrated. In addition, if EPA 

—> were to perform the modeling procedures, manufacturers would 

—> lose the initial opportunity to analyze and interpret the 

—> modeling results and conclusions for their products. Comments 

—» are requested on this possible approach. 

Environmental partitioning. Examples of models which 

could be used to evaluate the environmental partitioning of 

emission products are the Spatial Multimedia Compartmental 

Model (SMCM),16'

17 developed by the National Center for 

Intermedia Transport Research at UCLA, and Exposure and 

Ecotoxicity Estimation for Environmental Chemicals 

(E4CHEM) ,

18'19 developed by Gesellschaft fuer Strahlen (GSF) 

16 Cohen, Y. et al. (1990) Dynamic Partitioning of Organic 

Chemicals in Regional Environments: A Multimedia ScreeningLevel Approach. Environ. Sci. Technol. 24:1549-1558. 

17 Tsai, W. et al. (1991) Hydrogen Peroxide Levels in Los 

Angeles: A Screening-Level Evaluation. Atmos. Env. 25B:67-78. 

18 Trenkle, R. (1988) Fate Simulation of Organic 

Substances in the Atmospheric Mixing Layer. In: Environmental 

Meteorology, K. Grefen and J. Lobel (eds), Kluwer Academic 

Publishers. 

171 (jos] 
P.27 

responses after exposure to fuel/additive emissions as 

—» compared to controls (i.e., animals exposed to filtered air 

-4 and, in the case of additive testing, animals exposed to 

—» emissions of the base fuel). The detection of a reproducible 

and statistically significant positive response to at least 

one concentration of emissions may also be interpreted as a 

positive result. 

Ames Reverse Mutation Assay. The Ames assay is an in 

vitro test for mutagenicity and, by implication, for 

carcinogenicity. The assay makes use of five mutant strains 

of the bacterium Salmonella typhimurium which cannot grow in 

a medium deficient in histidine due to an inherited inability 

to produce this amino acid. Exposure to mutagenic (and 

possibly carcinogenic) substances can elicit reverse 

mutations, such that the bacteria regain their ability to grow 

in a histidine-deficient medium. In this test, bacteria will 

be exposed to the soluble organic (semi-volatile) and 

particulate extracts of fuel/additive combustion emissions. 

(Ames tests will not be required for evaporative emissions or 

for the gaseous fraction of combustion emissions.) After 

exposure, the cells will be plated on histidine-deficient 

media, both with and without metabolic activation, and 

incubated for a designated period of time. The number of 

colonies (revertants) growing on the plates will then be 

compared to the number of spontaneous revertants in control 

cultures. 

177 m 
P.28 

such as colchicine. After appropriate staining for labeled 

DNA, sister chromatid exchanges will be scored from cells 

arrested in the second mitotic division and the results 

compared with appropriate controls. 

2. Developmental Toxicity (Teratogenicity) Study 

This study is designed to provide information on 

potential dangers to the unborn which may arise from 

inhalation exposure of the female to fuel/additive emissions 

during pregnancy. Pregnant animals will be exposed to 

emissions during the major organ development period in the 

fetus (e.g., days 6-15 for rats and mice). The dams will be 

sacrificed on the day prior to normal parturition and the 

uterus examined for embryonic or fetal deaths. Viable fetuses 

will be examined for skeletal and soft tissue anomalies. 

These results will be evaluated relative to the number of 

spontaneous embryonic or fetal deaths and abnormalities in 

appropriate controls. The initially proposed test guidelines 

for developmental toxicity calls for two different species to 

be examined. However, EPA asks for comment on whether one 

species would be sufficient for the screening purposes of Tier 

2. 

3. Reproduction and Fertility Screen 

The purpose of this test is to determine the potential 

reproductive toxicity to adult male and female animals caused 

—> by inhalation of fuel/additive emissions. Both males and 

179 [114] 
P.29 

—> females will be exposed to the emissions throughout an initial 

—> 42-day exposure period. In females, vaginal cell smears will 

—> be examined throughout this time, to track effects on the 

—>estrous cycle. At the end of the initial exposure period, a 

—> sufficient number of females will be mated to obtain at least 

—» ten pregnant females. Histopathological examination of the 

—> uterus and ovaries will be performed on the non-pregnant 

—> females, while the adult males will be evaluated by gross and 

—> histopathological examination of the reproductive organs and 

—> by assessing the number, morphology, and motility of sperm. 

-» Pregnant females will continue to be exposed to the test 

—> atmosphere throughout the pregnancy, and will be examined, 

—> along with their offspring, at the time of birth and at four 

—» days post-partum. 

As compared with appropriate control animals, positive 

results would include changes in the number and type of cells 

seen in vaginal smears, decreases in sperm number or motility 

or abnormalities of sperm structure, and pathologic changes 

found during gross or microscopic examination of male or 

female reproductive organs. A decrease in the number or 

viability of offspring would also be evidence of toxicity. 

4. Pulmonary Toxicity Screen 

This study involves a six-week inhalation exposure of 

laboratory rodents to fuel/additive emissions, with subsequent 

examination of lung tissues and cells. A satellite group of 

180 QTQ 
P.30 

changes, unusual respiration, diarrhea, increased or decreased 

urination, unusual vocalization, and decreased grip strength. 

To completely assess the neurotoxic potential of complex 

fuel/additive emissions, additional functional and 

neurohistochemical tests would be necessary. Used alone, the 

FONB may overlook adverse effects at the celluar level. Thus, 

EPA requests commment on whether an in vitro assay for 

determining the level of glial fibrillary acidic protein 

(GFAP)22'

23 should be required in addition to the FONB to 

broadly assess sensitive neurohistopathologic effects in test 

animals. Another alternative is to delete the FONB and to 

Jr address neurotoxicity by requiring only the GFAP assay. The 

4, GFAP assay is a sensitive indicator of adverse 

H 

neurotoxicologic effects. Because it is an in vitro test 

which can make use of brain tissue harvested from exposed 

animals used in other studies, it is also a relatively 

inexpensive option. EPA requests comment on these alternative 

approaches for Tier 2 testing of neurotoxic effects. 

6. Optional Histopathology 

If the Tier 1 literature search or emissions 

characterization suggest the potential for toxicity to other 

22

 In: Pesticide Assessment Guidelines, Subdivision F, 

Neurotoxicity Test Guidelines (1991). EPA-540/09-91-123. 

23 O'Callaghan, J.P. (1991) Quantification of Glial 

Fibrillary Acidic Protein: Comparison of Slot-immunobinding 

Assays with a Novel Sandwich ELISA. Neurotoxicology and 

Teratology, 13:275-281. 

182 [i%3 
P.31 

organ systems, then histopathology of the indicated organs 

should be performed, using the animals exposed in the 

pulmonary toxicity screen. For example, if adverse effects to 

the liver appear likely, as suggested from the literature or 

the presence of high levels of PAHs in the emissions, then it 

—» would be advisable to perform histopathology of the liver. On 

—> the other hand, if scientifically sound studies reported in 

—» the literature indicate no or very minimal potential for 

—» hepatic effects, then liver examination would not be 

—> necessary. Other organ systems likely to be of concern 

include the kidneys and the endocrine glands. These 

additional examinations are suggested because findings of 

potential adverse health effects in Tier 1 might require 

follow-up at the Tier 3 level, and if performed as adjuncts to 

required Tier 2 testing, these optional histopathology 

examinations might provide substantial incremental information 

at a relatively low incremental cost. At a minimum, organs of 

potential concern should be removed, weighed, and saved in 

storage for potential histopathological examination at a 

future time. However, the length of time which organs can be 

stored and still be of use is limited. EPA requests comment 

on whether histopathological examination of the liver, 

kidneys, and endocrine glands as an adjunct to the pulmonary 

toxicity screening test should be required rather than 

optional. 

7. Alternative Testing Approach 
P.32 

likely and that exposures appear significant, but the data may 

still be inadequate for a quantitatively advanced risk 

assessment. In this case, Tier 3 testing, targeted to provide 

the missing information, would be indicated. 

In this way, the principles and critical data elements of 

the risk assessment process would provide a useful guide for 

identifying significant information gaps and determining the 

specific objectives of potential Tier 3 testing. However, EPA 

does not intend to conduct a formal risk assessment as part of 

its decision on whether to promote a fuel or fuel additive (or 

group) to Tier 3. Rather, EPA would evaluate the quality and 

certainty of available toxicity and dose-response data and 

consider qualitatively whether estimated exposure weighs in 

favor of or against further testing. On this basis, EPA would 

determine whether additional information is necessary to 

adequately assess the risk of a fuel or additive. A formal 

risk assessment would be more likely to be developed later if 

there was a need for action to control or prohibit a product 

under the regulatory authority of section 211(c). 

—¥ The following section discuss the key factors which EPA 

—» would consider in identifying the need for and content of Tier 

-> 3 testing. 

191 0<s3 
P.33 

I i —> a. Statistical Issues 

wi -» As previously mentioned, scientific judgment will be 

Vj f —> exercised in determining whether Tier 3 tests are necessary 

' —> and, if so, which ones. An important factor in such judgments 

—»will be the interpretation of and significance ascribed to 

—> "negative" results obtained in Tiers 1 and 2. Evaluating 

—> negative data (i.e., no-effect data) can be more difficult 

—> than evaluating positive data, because questions often arise 

—» as to the reason for the negative result: Did aspects of the 

—» experimental design (e.g., very small numbers of animals) lead 

—» to the negative outcome or was the test substance inherently 

—> of very low or no toxicity? 

-> 

-» This specific question is addressed statistically by 

-» considering the probability of Type I and Type II errors. A 

—» Type I error occurs when a false positive conclusion is made, 

—» while a Type II error is a false negative conclusion. The 

—» acceptability of a specific Type II error is related to the 

-» acceptability of false negatives in the particular study being 

—> performed. For example, from a toxicological perspective, 

—» screening assays often have a relatively high probability of 

—» producing false negative outcomes, since some major aspects of 

—> organ or tissue toxicity are not being examined. Thus, an 

—» acceptable Type II error for screening assays would typically 

-» be low. However, the level of Type II error considered 

—> acceptable should be tempered by the goal of the study. A 

—> higher false negative conclusion (e.g., Type II error of 0.2) 

192 0*0 
P.34 

—> would generally be acceptable if it referred to an effect of 

—> minimal severity at a high-exposure test level relative to 

-» ambient concentration and if few people were likely to be 

—> exposed. The converse would also hold true. 

— > 

—» A number of factors increase the complexity of these 

—» statistical issues. For example, the design of the study will 

—> influence the Type I and II levels obtained and the standard 

-» statistical methods chosen. Therefore, the scientific quality 

—> of the statistical analyses and their relationship to the 

-» experimental design are quite important. For example, 

-» although minimum sample sizes are specified in the proposed 

—>regulations, these are only general guidelines. Variability 

—» between laboratories and the specifics of the study methods 

—> may allow a decrease or require an increase in sample size. 

-» These possibilities should be evaluated properly before the 

-> start of the study. 

—> 

—> In summary, scientifically sound statistical analyses are 

-» a crucial part of any good study and will provide key 

—> information for EPA to use in forming judgments on whether or 

—¥ not Tier 3 testing is needed. While it is not feasible to 

-4 list all possible scenarios and results for each Tier 2 

—> endpoint, the foregoing discussion elucidates how some of the 

—> statistical factors will be incorporated into EPA's decisions. 

193 
P.35 

b. Exposure Assessment 

A number of the proposed Tier 1 and 2 requirements will 

provide EPA with information on population exposures to fuel 

and additive emissions. This information includes 1) 

historical and/or projected production volumes, 2) types and 

emission rates of speciated emission components, 3) estimated 

urban, rural, and/or microenvironment exposures obtained 

through exposure modeling approaches, 4) evidence for 

bioconcentration from environmental modeling results, and 5) 

possible literature search findings on ambient, occupational, 

or epidemiological exposures. As mentioned above, this 

information will be considered qualitatively by EPA in 

determining whether Tier 3 testing is needed. 

Significant public health concerns might sometimes be 

revealed by the exposure information itself. This might be 

the case, for example, if there were an anticipated release in 

excess of, say, 1,000 kg per year of individual emission 

compounds (in addition to "criteria" pollutants) with known 

toxicities, or if the anticipated exposure scenarios 

approached or exceeded current estimates of apparently safe 

levels of known toxicants. In the case of fuels and their 

associated high-volume bulk additives, EPA will generally 

assume that human and environmental exposures will be of 

—> sufficient level and extent that significant observed adverse 

—> effects would indicate a need for follow-up in Tier 3. This 

exposure assumption reflects the high production and 

194 M 
P.36 

consumption of these products, either at the present time or 

as anticipated in the future. Thus, decisions to promote 

these products to Tier 3 would be based on the degree to which 

additional testing is needed to clarify the results and 

potential health effect implications of Tier 1 and Tier 2 

data. It cannot be assumed, on the other hand, that fuel 

additives used in relatively low concentrations or produced in 

relatively low volumes would automatically be excused from 

Tier 3. For these products, test results indicative of severe 

health effects and/or high exposure levels in circumscribed 

areas might be cause for escalation to Tier 3. 

c. Health Assessment 

General criteria for evaluating the potential public 

health effects associated with fuel and additive emissions 

would include 1) the number of positive and.negative outcomes 

related to each endpoint, 2) the identification of 

concentration-effect relationships, 3) the statistical 

sensitivity and significance of such studies, 4) the severity 

of the observed effects (e.g., whether the effects would be 

likely to lead to incapacitating or irreversible conditions), 

5) the number of species involved in the reported tests, and 

6) the consistency and clarity of apparent mechanisms, target 

organs, and outcomes. Additional parameters which would 

influence the decision on whether to require Tier 3 would 

include 1) findings of environmental persistence of the 

emissions and/or the ability of the emissions to accumulate in 

195 [itfc|/fO 
P.37 

living organisms, 2) the nature and amount of known toxic 

agents in the emissions stream, and 3) the observation of 

lesions which specifically implicate inhalation as an 

important exposure route for inducing adverse health effects. 

—> These criteria would be evaluated in conjunction with the 

—> results of the exposure assessment to determine whether or not 

—> higher level testing was needed. In this decision, both the 

—> biological and statistical significance of the results of 

—» Tiers 1 and 2 would be taken into account. Generally, 

—>escalation to Tier 3 would be considered when remaining 

—>uncertainties about the significance of observed outcomes 

—> and/or exposures interfered with EPA's ability to make 

—»reasonable estimates of the attendant public health risks. On 

—» the other hand, if no statistically significant effects were 

—» obtained at any exposure level in a scientifically sound Tier 

-> 2 study, and if other major sources of concern did not arise 

—> (e.g., reports in the literature of contradictory test results 

—» or toxic effects of structurally related compounds) , then Tier 

—» 3 testing would almost certainly not be required for the 

—> endpoint in question. This assumes that relevant, high-

—> quality statistical analysis had been done to permit the 

—> negative test results to be properly evaluated and 

—» interpreted. The statistical analyses recommended for Tier 2 

-4 in an earlier discussion, including determination of Type I 

—> and II error, should enable reasonable conclusions to be drawn 

—» as to the significance of negative findings. Factors to be 

196 [ni] 
P.38 

-4 taken into account include the toxicological nature of the 

—> findings and the exposure levels used in the test. For 

-4 example, if the statistical analyses were applied to a 

—> "severe" endpoint (e.g., major fetal abnormalities, major lung 

-4 pathology, etc.) and the exposure in question was moderate, 

-4 then 0.1 would be an appropriate Type II error level. In 

—> contrast, if a high concentration limit test caused a 

—» relatively minor effect (e.g., a small change in lung lavage 

-4 protein) , a higher Type II error would be allowed (e.g., 0.2) , 

—* effectively increasing the chance of false negative 

-4 conclusions. 

Evaluation of Tier 2 Results. The specific outcomes 

which would be considered positive and negative results for 

each proposed Tier 2 test are mentioned briefly in the 

previous descriptions of Tier 2 requirements and are defined 

and interpreted more precisely in the proposed regulations 

which follow this NPRM preamble. For example, three primary 

studies are included in Tier 2 which relate to carcinogenicity 

and mutagenicity: the Ames, SCE, and micronucleus assays. As 

compared with appropriate controls, a statistically 

significant dose-related positive response in any one of these 

assays could be cause for concern, as would positive outcomes 

for at least one concentration in two or more of these tests. 

Such outcomes would be indicative of mutagenic risk; however, 

depending on the internal and historical consistency of these 

197 [Hfl 
P.39 

results and their relationship to projected exposures, further 

testing might be required to determine the significance of 

this mutagenic activity in human populations exposed by 

inhalation. These outcomes would also indicate that the 

emissions could initiate some of the mechanisms involved in 

carcinogenesis. However, the production of malignancy is a 

multi-step process, and these results would generally not in 

themselves be sufficient to determine whether the emissions 

were in fact carcinogenic. Thus, additional testing might be 

required under Tier 3 to better evaluate the associated cancer 

-4 risks. In contrast, if no statistically significant results 

-4 were obtained in the three assays and no conflicting results 

—¥ found in the literature or in other Tier 2 tests, then Tier 3 

-4 follow-up for carcinogenicity/mutagenicity would, in all 

-4 likelihood, not be required. 

To take another example, determination of the need to 

further investigate teratogenic risks would take into account 

the results of both the inhalation developmental toxicity 

study and the reproduction and fertility assessment of Tier 2. 

—¥ Negative results in both of these tests (according to 

—¥ statistically sound principles) , if not refuted by the 

—> existing literature, would argue against requiring additional 

—¥ testing for developmental or reproductive effects at the Tier 

—¥ 3 level. Positive results would include a decrease in 

neonatal viability relative to that in control studies, a 

significant change in the proportion of viable male vs. female 

198 [m] 
P.40 

fetuses or offspring, the presence of soft tissue or skeletal 

abnormalities, and an increased rate of embryonic or fetal 

resorption. Other positive outcomes of the reproduction and 

fertility assessment, such as abnormal changes in sperm 

structure or function, vaginal cytology, or reproductive organ 

histopathology, would be indicative of hazards to the adult 

reproductive systems. The need for additional evaluation 

under Tier 3 would depend on the number of species for which 

positive results were obtained, the specificity, severity, and 

consistency of results, the presence or absence of a 

concentration-effect relationship, and the significance of 

these outcomes in view of projected exposure scenarios. The 

greater the remaining uncertainty regarding the risk of 

teratogenic or reproductive effects after analysis of such 

factors, the higher would be the likelihood that Tier 3 would 

be required. 

-4 Similarly, statistically valid negative results obtained 

—¥ in other Tier 2 tests, in the absence of significant related 

-4 concerns raised in the literature, would suggest that Tier 3 

—¥ not be required. On the other hand, if adverse effects are 

-4 found at Tier 2 and/or reported in the literature, EPA would 

-4 determine if Tier 3 follow-up is required by attempting to 

—¥ evaluate the nature, severity, and significance of the 

-4 findings in light of the likely exposures. If EPA determines 

—¥ that Tier 3 testing is required to resolve the remaining 

-4 uncertainties, the Tier 3 requirements would reflect both 

199 [uQ 
P.41 

-4positive and negative results. For example, if the results of 

-4 Tier 2 were positive for pulmonary effects but negative for 

—¥ neurotoxicity (according to criteria discussed earlier), and 

-¥ if these results were consistent with the literature, only 

-4 pulmonary toxicity would be a likely candidate for Tier 3 

-4 follow-up testing. 

Acute Health Assessment. Under the assumption that 

emissions exposures will generally be low and thus more likely 

to cause longer-term effects, this proposed rulemaking does 

not focus on acute effects. However, the purpose of CAA 

section 211 is to protect the public health, whatever the 

exposure duration, and potential acute effects could also be 

a consideration in the Tier 3 decision. 

EPA is currently developing a standardized method of 

assessing acute noncancer health effects, and this method 

might be useful for evaluations under this proposed program. 

The new method will estimate levels of exposure which are 

expected to pose no or minimal health risk to susceptible 

subpopulations as well as levels posing incrementally higher 

risks. A draft of this method is expected in early fiscal 

year 1993. After a period for comment by EPA's Scientific 

Advisory Board (SAB) and the public, a final draft is expected 

in fiscal year 1994. Thus, the new methodology may be 

available for use in a time frame consistent with the needs of 

this program. If acute risk must be assessed prior, to the 

200 [kifrto] 
P.42 

— ¥ As previously mentioned, Tier 3 requirements could also 

—¥ include additional work to improve the exposure estimates 

-> submitted in compliance with Tier 1. The need for additional 

—¥ exposure data would depend in part on the limitations of the 

—¥ Tier 1 estimates, and in part on the nature of the associated 

—¥ health effects information. That is, highly precise and 

—• accurate exposure information would not be cost effective if 

-4 the health assessment were based on limited and/or uncertain 

—¥ results, and vice versa. 

—¥ 

—¥ The approach which EPA plans to use in determining the 

—¥ potential need for greater precision and accuracy in the 

—¥ exposure information is to consider the slope of the toxic 

—¥ response. If the slope is steep within the range of potential 

—¥ human exposures, then a small change in exposure is likely to 

—¥ have a major impact on the eventual risk assessment. Greater 

-4 precision would thus be required in the exposure calculation. 

—¥ If adverse health effects appear likely within the projected 

—¥ range of exposures, improved estimates might also be needed to 

-4 determine the conditions and locations under which these 

—¥ exposures might occur as well as the size of the potentially 

-4 affected populations. On the other hand, if only minor health 

—¥ effects occur at levels well above ambient concentrations and 

-4 only a relatively small number of people are likely to be 

—¥ exposed, then additional refinements of the exposure 

-4 calculations would not be warranted. 

208 u 
P.43 

— ¥ Requirements for exposure assessment at the Tier 3 level 

—¥ could include physical monitoring studies or the application 

-4 of more sophisticated modeling techniques, some of which are 

—¥ described in Section VI.B.2. However, the precise nature of 

—¥ the requirements would be strongly influenced by interim 

-¥ advances that are expected in the growing science of exposure 

—¥ assessment. For example, ongoing research on human activity 

—¥ patterns may be able to identify which microenvironments are 

—¥ key determinants of exposure to the emissions of fuels and 

—¥ additives. In addition, the general topic of gasoline 

—¥ exposure is receiving increased attention by the scientific 

—¥ community as a topic for research, in recognition of the 

—¥ limited knowledge base currently available for determining the 

—¥ risks from mobile source emissions and from the use of motor 

—» vehicle fuels.25 Thus, new information and new scientific 

—¥ methodologies for monitoring and estimating population 

—¥ exposures are expected to emerge in a time frame which will be 

-4 useful for guiding the types of exposure assessments which 

-¥ might be required at the Tier 3 level. 

EPA requests comments on the possible scenarios and test 

guidelines outlined above, and solicits suggestions on other 

health effect and exposure studies which should be considered. 

An alternative approach for determining Tier 3 testing 

requirements would permit the responsible manufacturers to 

25 Journal of Exposure Analysis and Environmental 

Epidemiology, January-March, 1992. 

209 [dod* J 
P.44 

Various alternative provisions are under consideration 

for this purpose. First, the vulnerable companies could be 

excused from one or more of the program's requirements. For 

example, they could be excused from all Tier 2 biological 

testing or could be required to conduct only those Tier 2 

tests which address the endpoints mandated by statute 

(carcinogenicity, mutagenicity, and teratogenicity). Another 

alternative would be to require only the Tier 1 literature 

search for such companies. To ensure that no small additive 

companies would be financially stressed by the regulations, 

complete program exemptions might be necessary. However, the 

potential health and environmental effects associated with an 

additive product are generally not related to the size of its 

-4 producer, and EPA does not favor this alternative. On the 

-4 other hand, because risk is partly a function of exposure, and 

—» potential exposure to an additive's emissions is related to 

-4 the volume produced and sold, appropriate measures of volume 

—¥ in conjunction with other relevant financial parameters may be 

-4 reasonable to consider in determining possible small business 

—¥ allowances. 

Public comment is requested concerning these small 

business issues and alternative ideas for possible small 

business allowances or exemptions. 

D. Possible Exemption for "Da Minimis" Factors 

220 [2o«] 
P.45 

commentary. Instead, the purpose of the proposed modification 

process is to cillow only persons who experience unforeseen 

difficulties or accidents in conducting the needed tests to 

request modification of the requirements in order to avoid 

being in violation of the rule. However, section 211(e) 

requires the requisite (Tier 1 and Tier 2) information to be 

submitted to EPA for previously registered products within 

three years after the effective date of the rule. 

Accordingly, EPA proposes that modification requests must be 

submitted as soon as the manufacturer is aware of the 

difficulty, thus prohibiting persons from waiting until the 

deadline before informing EPA of circumstances which might 

prevent EPA from, receiving the data on time. 

X. Confidential Business Information 

.A provision under section 211(b) (2) states that the 

results of health effects tests "conducted in conformity with 

test procedures and protocols established by the 

Administrator" shall not be considered confidential. Thus, 

information supplied to EPA in compliance with testing 

requirements will be available to the public. However, the 

statute specifically differentiates between health effects 

test data and other information submitted for registration. 

-4 Thus, data on product composition and other registration 

-4 information not integral to the testing program will continue 

—¥ to be held in confidence. 

227 0<] 
P.46 

tt S 

4 

EPA response to OMB's comments are available in the public 

docket for this rulemaking. 

-4 While the costs of the proposed program would be expected 

-4 to vary widely between various fuel/additive groups and among 

-4 individual manufacturers, a hypothetical example may help to 

—¥ clarify the proposed scope, time frame, and costs of the 

—¥ program. Based on the analysis provided in the regulatory 

-4 support document, a possible testing scenario and the 

-4 associated costs for a hypothetical group of products is 

—¥ discussed below and summarized in Figure 6. The costs 

—¥ displayed would be incurred in evaluation and testing of a 

-4 fuel selected as the hypothetical group representative. These 

—¥ costs would subsequently be shared by all of the manufacturers 

-4 with products enrolled in the group. The requirements and 

-¥ costs assume that the group consists of 40 fuels and additives 

—¥ which contain no "atypical" elements, that the group does not 

—¥ qualify for exemption from evaporative emission testing, and 

—¥ that adequate existing studies are not available to fulfill 

—¥ any of the speciation or biological test requirements. 

—¥ Therefore, under this hypothetical situation, all of the 

—¥ potential requirements of Tiers 1 and 2 must be conducted. 

—¥ Combustion emission generation procedures are assumed to be 

—¥ performed using a light-duty vehicle. 

[>rD 

230 
P.47 

Figure 6: Hypothetical Cost Scenario 

Tier 1 Requirements 

Data Research and Analysis 

Vehicle Costs 

Combustion Emission Generation/Speciation 

Evaporative Emission Generation/Speciation 

Total Tier 1 Costs 

Cost 

$ 16,500 

32,500 

27,000 

4,000 

$ 80,000 

Tier 2 Requirements 

Combustion Emission Generation 

Biological Tests on Combustion Emissions 

Evaporative Emission Generation 

Biological Tests on Evaporative Emissions 

Total Tier 2 Costs 

$ 59,000 

294,000 

16,000 

286,000 

$ 655,000 

Administrative and Reporting Costs $ 157,000 

Total Tier 1, Tier 2, Administrative Costs $ 892,000 

Estimated Costs of Tier 3 $ 2-2.5 million 

Total Costs $ 3-3.5 million 

231 
P.48 

^t -4 Under this scenario, the cost of conducting all 

• -¥ requirements of Tier 1 is estimated at approximately $80,000. 

( 

—¥ Of this, EPA estimates data research and analysis (literature 

-4 search and data modeling) costs to be about $16,500, and 

-4 vehicle-related costs (acquisition/operation/mileage 

-4 accumulation) to be about $32,500. EPA estimates a cost of 

—¥ $27,000 for generation and speciation of combustion emissions, 

—¥ and approximately $4,000 for generation and speciation of 

-4 evaporative emissions. 

-¥ 

—¥ Further, EPA estimates the costs of conducting all Tier 

-¥ 2 test requirements to total nearly $655,000 under this 

—¥ hypothetical example. Including set-up costs, combustion 

—remission generation costs are estimated at about $59,000, 

—¥ while biological testing of combustion emissions is estimated 

-4 at. nearly $294,000. The cost of generating adequate 

-4 evaporative emissions to conduct all Tier 2 screening tests 

—¥ would be approximately $16,000, and conducting Tier 2 tests on 

-4 these emissions is estimated to cost $286,000. 

-¥ 

—¥ The administrative costs for organizing and administering 

—¥ the group and for reporting the Tier 1 and 2 results to EPA is 

—¥ judged to be nearly $157,000. Adding this to the Tier 1 and 

—¥ Tier 2 costs provided above yields a total cost of 

-4 approximately $892,000 for the group as a whole. Assuming 

—¥ these costs are incurred over a three-year period and are 

—¥ divided equally among the 40 products in the group, the cost 

232 [p-n} 
P.49 

-4 to a manufacturer with a single product in this group would be 

-4 about $7,300 annually for three years, or $22,000 in total. 

-¥ 

— ¥ Let us assume further that, within 18 months of receiving 

—¥ the group's report, EPA determines that the submittal is 

-4 complete and that the required Tier 1 and 2 evaluations have 

-¥ been adequately performed. However, a number of health 

—¥ concerns are raised by the results. The literature search 

-4 suggests a high potential for toxic liver effects to be caused 

—¥ by chronic exposure to the combustion emissions of fuels 

—¥ similar to those in the group, and the Tier 2 results indicate 

—¥ a need for further evaluation of possible carcinogenic and 

—¥ pulmonary effects of these emissions. In addition, a large 

-4 and widespread population is expected to be exposed to the 

—¥ emissions of products in this group. Thus, EPA determines 

-4 that more rigorous testing is necessary under Tier 3 to 

-4 clarify the potential risks posed by this group of products. 

-¥ 

-4 Under this hypothetical scenario, two tests are likely to 

-4 be required to address the identified areas of concern: a 

—¥ two-year combined chronic toxicity/carcinogenicity study 

—¥ conducted in two species, and a metabolism study to elucidate 

—¥ the potential carcinogenic mechanisms. The group is given 

—¥ three years in which to complete these tests. The total cost, 

—¥ including costs for emission generation and biological 

-4 testing, is estimated at 2 to 2.5 million dollars. When 

—¥ divided equally among the 40 products in the group and spread 

233 
P.50 

J 

* 

—¥ over the three-year compliance period, the Tier 3 testing cost 

U | -4 per product in this group would be in the range of $17-21,000 

—¥ annually for three years. 

-4 

— ¥ In sum, EPA estimates that the total costs to this 

—¥ hypothetical group would range from approximately 3 to 3.5 

-4 million dollars, incurred over a seven or eight year time 

—¥ period. The total cost for each product would range from 

-4 about $75,000 to $87,500, averaging about $10-12,000 per year. 

This proposed regulation was submitted to the Office of 

Management and Budget (OMB) for review as required by 

Executive Order 12291. Any written comments from OMB and any 

EPA response to OMB's comments are available in the public 

docket for this rulemaking. 

XTV. Compliance with Regulatory Flexibility Act 

Under Section 605 of the Regulatory Flexibility Act, 5 

USC 601 et reg., the Administrator is required to assess the 

economic impact of this proposed regulation on small business 

entities. Accordingly, a Regulatory Flexibility Analysis 

(RFA) has been prepared and is available in the public docket. 

The RFA compares the estimated financial effects of the 

proposed programs on large and small companies as defined by 

the Small Business Administration. 

234 \M