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imazethapyr Pesticide Tolerance 8/02


ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 180

[OPP-2002-0189; FRL-7193-4]


Imazethapyr; Pesticide Tolerance

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

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SUMMARY: This regulation establishes a tolerance for combined residues
of imazethapyr, its metabolite CL 288511 and its metabolite CL 182704
in or on rice bran, rice grain, and rice straw. This regulation also
establishes a tolerance for combined residues of imazethapyr and its
metabolite CL 288511 in or on crayfish and meat byproducts of cattle,
goat, hog, horse, and sheep. BASF requested these tolerances under the
Federal Food, Drug, and Cosmetic Act, as amended by the Food Quality
Protection Act of 1996.

DATES: This regulation is effective August 29, 2002. Objections and
requests for hearings, identified by docket ID number OPP-2002-0189,
must be received on or before October 28, 2002.

ADDRESSES: Written objections and hearing requests may be submitted by
mail, in person, or by courier. Please follow the detailed instructions
for each method as provided in Unit VI. of the SUPPLEMENTARY
INFORMATION. To ensure proper receipt by EPA, your objections and
hearing requests must identify docket ID number OPP-2002-0189 in the
subject line on the first page of your response.

FOR FURTHER INFORMATION CONTACT: By mail: Jim Tompkins, Registration
Division (7505C), Office of Pesticide Programs, Environmental
Protection Agency, 1200 Pennsylvania Ave., NW.,Washington, DC 20460;
telephone number: 703-305-5697; e-mail address: Tompkins.Jim@epa.gov.

SUPPLEMENTARY INFORMATION:

I. General Information

A. Does this Action Apply to Me?

    You may be affected by this action if you are an agricultural
producer, food manufacturer, or pesticide manufacturer. Potentially
affected categories and entities may include, but are not limited to:

------------------------------------------------------------------------
                                                 Examples of Potentially
             Categories                 NAICS       Affected Entities
------------------------------------------------------------------------
Industry                                    111  Crop production
                                            112  Animal production
                                            311  Food manufacturing
                                          32532  Pesticide manufacturing
------------------------------------------------------------------------

    This listing is not intended to be exhaustive, but rather provides
a guide for readers regarding entities likely to be affected by this
action. Other types of entities not listed in the table could also be
affected. The North American Industrial Classification System (NAICS)
codes have been provided to assist you and others in determining
whether or not this action might apply to certain entities. If you have
questions regarding the applicability of this action to a particular
entity, consult the person listed under FOR FURTHER INFORMATION
CONTACT.

B. How Can I Get Additional Information, Including Copies of this
Document and Other Related Documents?

    1. Electronically.You may obtain electronic copies of this
document, and certain other related documents that might be available
electronically, from the EPA Internet Home Page at http://www.epa.gov/.
To access this document, on the Home Page select ``Laws and
Regulations'', ``Regulations and Proposed Rules,'' and then look up the
entry for this document under the ``Federal Register--Environmental
Documents.'' You can also go directly to the Federal Register listings
at http://www.epa.gov/fedrgstr/. A frequently updated electronic
version of 40 CFR part 180 is available at http://www.access.gpo.gov/
nara/cfr/cfrhtml--00/Title--40/40cfr180--00.html, a beta site currently
under development. To access the OPPTS Harmonized Guidelines referenced
in this document, go directly to the guidelines at http://www.epa.gov/
opptsfrs/home/guidelin.htm.
    2. In person. The Agency has established an official record for
this action under docket ID number OPP-2002-0189. The official record
consists of the documents specifically referenced in this action, and
other information related to this action, including any information
claimed as Confidential Business Information (CBI). This official
record includes the documents that are physically located in the
docket, as well as the documents that are referenced in those
documents. The public version of the official record does not include
any information claimed as CBI. The public version of the official
record, which includes printed, paper versions of any electronic
comments submitted during an applicable comment period is available for
inspection in the Public Information and Records Integrity Branch
(PIRIB), Rm. 119, Crystal Mall 2, 1921 Jefferson Davis Hwy.,
Arlington, VA, from 8:30 a.m. to 4 p.m., Monday through Friday,
excluding legal holidays. The PIRIB telephone number is (703) 305-5805.

II. Background and Statutory Findings

    In the Federal Register of September 27, 2000 (65 FR 58074) (FRL-
6744-6), EPA issued a notice pursuant to section 408 of the Federal
Food, Drug, and Cosmetic Act (FFDCA), 21 U.S.C. 346a, as amended by the
Food Quality Protection Act of 1996 (FQPA) (Public Law 104-170), announcing the
filing of a pesticide petition (PP 0F6168) by American Cyanamid, now
BASF, 26 Davis Drive, Research Triangle Park, NC 27709. This notice
included a summary of the petition prepared by American Cyanamid, the
registrant. There were no comments received in response to the notice
of filing.
    The petition requested that 40 CFR 180.447 be amended by
establishing a tolerance for combined residues of the herbicide
imazethapyr, 2-[4,5-dihydro-4-methyl-4-(1-methylethyl)-5-oxo-1H-
imidazol-2-yl]-5-ethyl-3-pyridine carboxylic acid as it free acid or
ammonium salt and its metabolite CL 288511, 2-[4,5-dihydro-4-methyl-4-
(1-methylethyl)-5-oxo-1H-imidazol-2-yl]-5-(1-hydroxyethyl)-3-pyridine
carboxylic acid both free and conjugated, in or on rice grain at 0.5
parts per million (ppm), rice straw at 0.3 ppm, and crayfish at 0.1
ppm.
    Section 408(b)(2)(A)(i) of the FFDCA allows EPA to establish a
tolerance (the legal limit for a pesticide chemical residue in or on a
food) only if EPA determines that the tolerance is ``safe.'' Section
408(b)(2)(A)(ii) defines ``safe'' to mean that`` there is a reasonable
certainty that no harm will result from aggregate exposure to the
pesticide chemical residue, including all anticipated dietary exposures
and all other exposures for which there is reliable information.'' This
includes exposure through drinking water and in residential settings,
but does not include occupational exposure. Section 408(b)(2)(C)
requires EPA to give special consideration to exposure of infants and
children to the pesticide chemical residue in establishing a tolerance
and to ``ensure that there is a reasonable certainty that no harm will
result to infants and children from aggregate exposure to the pesticide
chemical residue....''
    EPA performs a number of analyses to determine the risks from
aggregate exposure to pesticide residues. For further discussion of the
regulatory requirements of section 408 and a complete description of
the risk assessment process, see the final rule on Bifenthrin Pesticide
Tolerances (62 FR 62961, November 26, 1997) (FRL-5754-7).
    After analysis of submitted residue chemistry data, EPA determined
that appropriate tolerances for rice and crayfish differ from those
proposed by the registrant. EPA determined that a tolerance of 1.2 ppm
is needed for rice bran; no tolerance for rice bran was proposed by the
registrant. EPA also determined that tolerances should be 0.20 ppm
instead of 0.5 ppm for rice grain, and 0.15 ppm instead of 0.3 ppm for
rice straw. Further, EPA determined that the tolerance expression for
rice commodities should be for imazethapyr and the metabolites CL
288511 and CL 182704 (5-[1-(beta-D-glucopyranosyloxy)ethyl]-2-[4,5-
dihydro-4-methyl-4-(1-methylethyl)-5-oxo-1H-imidazol-2-yl]-3-
pyridinecarboxylic acid); the registrant's proposed tolerance
expression for rice commodities was for imazethapyr as the free acid
and ammonium salt and CL 288511 both free and conjugated. For crayfish,
EPA determined that the tolerance expression should be for imazethapyr
and CL 288511; the registrant's proposed tolerance expression for
crayfish was for imazethapyr as the free acid and ammonium salt and CL
288511 both free and conjugated. Finally, EPA determined that
tolerances of 0.10 ppm for imazethapyr and CL 288511 need to be
established for meat byproducts of cattle, goat, hog, horse, and sheep;
the registrant did not propose tolerances for these commodities. EPA
determined that tolerances are not needed for eggs; milk; meat and fat
of cattle, goat, hog, horse, and sheep; and poultry commodities because
there is no reasonable expectation of finite residues based on the
calculated maximum total dietary burdens and the results of the poultry
metabolism study.

III. Aggregate Risk Assessment and Determination of Safety

    Consistent with section 408(b)(2)(D), EPA has reviewed the
available scientific data and other relevant information in support of
this action. EPA has sufficient data to assess the hazards of and to
make a determination on aggregate exposure, consistent with section
408(b)(2), for a tolerance for combined residues of imazethapyr and its
metabolite CL 288511 on crayfish and meat byproducts of cattle, goat,
hog, horse, and sheep at 0.10 ppm, and for tolerances for combined
residues of imazethapyr, its metabolite CL 288511, and its metabolite
CL 182704 on rice bran at 1.2 ppm, rice grain at 0.20 ppm, and rice
straw at 0.15 ppm. EPA's assessment of exposures and risks associated
with establishing the tolerance follows.

A. Toxicological Profile

    EPA has evaluated the available toxicity data and considered its
validity, completeness, and reliability as well as the relationship of
the results of the studies to human risk. EPA has also considered
available information concerning the variability of the sensitivities
of major identifiable subgroups of consumers, including infants and
children. The nature of the toxic effects caused by imazethapyr are
discussed in the following Table 1 as well as the no observed adverse
effect level (NOAEL) and the lowest observed adverse effect level
(LOAEL) from the toxicity studies reviewed.
Table 1.--Acute, Subchronic, Chronic, and Other Toxicity
Guideline No.
Study Type
MRID No. (year)/Classification/Doses
Results
870.1100

Acute Oral 00159375 (1985) Acceptable/guideline
5,000 mg/kg
LD50 =5,000 mg/kg (male and female rats)
Toxicity Category IV
870.1200 Acute Dermal 00159375 (1985)
Acceptable/guideline
2,000 mg/kg
LD50 =2,000 mg/kg(male and female rabbits)
Toxicity Category III
870.1300 Acute Inhalation 00159378 (1985)
Acceptable/guideline
3.27 mg/L
LD50 =3.27 mg/L (male and female rats)
Toxicity Category III
870.2400 Primary Eye Irritation 00159375 (1985)
Acceptable/guideline
0.1 mL
Not an irritant
Toxicity Category III
870.2500 Primary Skin Irritation 00159375 (1985)
Acceptable/guideline
0.5 mL
Not an irritant
Toxicity Category IV
870.2600 Dermal Sensitization 00159379 (1985)
Acceptable/guideline
0.4 mL
Not a skin sensitizer
(Toxicity Category Not Applicable)
870.3100 90–Day oral toxicity
rodents-rat
00159381 (1986)
Acceptable/guideline
0, 1,000, 5,000, or 10,000 ppm 0, 50, 250, or
500 mg/kg/day
NOAEL = 500 mg/kg/day (HDT).
LOAEL = Not observed.
870.3150 90–Day oral toxicity
nonrodents-dog
00159382 (1985)
Acceptable/guideline
0, 1,000, 5,000 or 10,000 ppm 0, 25, 125 or
250 mg/kg/day
NOAEL = 250 mg/kg/day (HDT).
LOAEL = Not observed.
870.3200 21–Day dermal toxicity-
rabbit
00159383 (1985)
Acceptable/guideline
0, 50, 200, or 1,000 mg/kg/day 0, 54.8, 219.3,
or 1,096.5 mg/kg/day (adjusted for purity)
NOAEL = 1,096 mg/kg/day (HDT).
LOAEL = Not observed.
870.3700 Prenatal developmental
in rodents - rat
40429417 (1985)
Acceptable/guideline
0, 125, 375, or 1,125 mg/kg/day
Maternal: NOAEL = 375 mg/kg/day
LOAEL = 1,125 mg/kg/day based on increased
incidences of clinical signs during the gestation
Developmental: NOAEL = 1,125 mg/kg/day
LOAEL =Not observed
870.3700 Prenatal developmental
in nonrodents-
rabbit
00159384 (1986)
Acceptable/guideline
0, 100, 300, or 1,000 mg/kg/day
Maternal: NOAEL = 300 mg/kg/day
LOAEL = 1,000 mg/kg/day based on an increased incidence
of clinical signs during gestation, ulcerations
in the mucosal layer of the stomach and gall bladder,
increased abortions, and maternal deaths.
Developmental: NOAEL = 1,000 mg/kg/day (HDT)
LOAEL = Not observed
870.3800 Reproduction and
fertility effects-rat

40429418 (1987)
Acceptable/guideline
0, 1,000, 5,000 or 10,000 ppm 0, 50, 250 or
500 mg/kg/day

Parental/Systemic NOAEL = 500 mg/kg/day (HDT).
LOAEL = Not observed.
Reproductive NOAEL = 500 mg/kg/day (HDT).
LOAEL = Not observed.
Offspring NOAEL = 500 mg/kg/day (HDT).
LOAEL = Not observed.
870.4100 Chronic toxicity-dog 40429416 (1987)
Acceptable/guideline
0, 1,000, 5,000 or 10,000 ppm 0, 25, 125, or
250 mg/kg/day
NOAEL = 250 mg/kg/day (HDT).
LOAEL = Not observed.
870.4300 Chronic/ Carcinogenicity-
rat.
40429414 (1987)
Acceptable/guideline
0, 1,000, 5,000, or 10,000 ppm 0, 50, 250, or
500 mg/kg/day
NOAEL = 500 mg/kg/day (HDT).
LOAEL = Not observed.
No evidence of carcinogenicity.
870.4300 Carcinogenicity mouse. 40429415 (1987)
Acceptable/guideline
0, 1,000, 5,000, or 10,000 ppm 0, 150, 750,
or 1,500 mg/kg/day
NOAEL = 750 mg/kg/day
LOAEL = 1,500 mg/kg/day (HDT) based on the decrement in body weight gain
No evidence of carcinogenicity at doses tested.
870.5100 Gene Mutation 00159719 (1986)
Acceptable/guideline
0, 50, 158, 500, 1,000, 1581, 3162 or 5,000
µg/plate
Non-mutagenic when tested up to 5,000 µg/plate, in
presence and absence of metabolic activation, in S.
typhimurium strains TA98, TA100, TA1535, TA1537,
and TA 1538 and E.coli strain WP2uvra.
870.5300 Gene Mutation 40429419 (1986)
Acceptable/guideline
up to 3333 µg/mL (limit of solubility) and 4000
µg/mL (beyond limit of solubility)
Negative for induction of forward mutation at the
HPRT locus in Chinese hamster ovary cells, in the
presence or absence of S9-activation at doses up to
limit of solubility (3,333 µg/mL) and beyond (4,000
µg/mL).
870.5375 Chromosome aberration 40438201 (1986)
Acceptable/guideline
0, 1.14, 1.71, 1.82, 2.05, and 2.28 mg/ml with
and without S9 activation
Did not induce structural chromosome aberration in
Chinese hamster lung (V79) cell cultures in the
presence and absence of activation up to cytotoxic
concentrations.
870.5450 Dominant Lethal
Assay
00159720 (1985)
Unacceptable/guideline
0, 200, 1,000 or 2,000 mg/kg
Negative for dominant lethal effects (chromosomal
damage) at doses up to 2,000 mg/kg.
870.5550 Other Genotoxicity 00159721 (1985)
Acceptable/guideline
0, 0.13, 0.4, 1.3, 4.0, 13, 40, 133, 400, 1,333,
or 4,000 µg/mL
No evidence that unscheduled DNA synthesis was induced
by imazethapyr, as determined by radioactive
tracer procedures [nuclear silver grain counts].
870.7485 Metabolism and
pharmacokinetics -
rat
40429420 and 41467703 (1987)
Acceptable/guideline
5.7 mg/kg single dose; 1,000 mg/kg single
dose and 3 daily doses of 250 mg/kg followed
by a single dose of 1000 mg/kg;
1,000 mg/kg/day single and repeated dose
In a rat metabolism study, almost 100% of the administered
radiolabeled test material was recovered in
the excreta within 96 hours (89–95% in the urine
and 6–11% in the feces). Greater than 95% of the
oral dose was excreted in the first 31 hours. The
major residue in both urine and feces was the parent
compound. Approximately 2% of the oral dose
was metabolized and excreted as CL 288511 (1-hydroxy
ethyl derivative of AC 263,499, parent).
A high percentage of the administered material was
excreted in the urine as the unmodified parent compound
(> 97%) and a very small amount as the CL
288511. In the high dose group, the unmodified parent
compound was the major fecal component in
both sexes, particularly at 12 hours or less. The CL
288511 was the major metabolite. One unknown
was also found in significant quantities. In the low
dose group, six components were found in the
feces: parent compound, the CL 288511, the unknown
previously mentioned and several minor unknowns.
B. Toxicological Endpoints

    The dose at which no adverse effects are observed (the NOAEL) from
the toxicology study identified as appropriate for use in risk
assessment is used to estimate the toxicological level of concern
(LOC). However, the lowest dose at which adverse effects of concern are
identified (the LOAEL) is sometimes used for risk assessment if no
NOAEL was achieved in the toxicology study selected. An uncertainty
factor (UF) is applied to reflect uncertainties inherent in the
extrapolation from laboratory animal data to humans and in the
variations in sensitivity among members of the human population as well
as other unknowns. An UF of 100 is routinely used, 10X to account for
interspecies differences and 10X for intra species differences.
    For dietary risk assessment (other than cancer) the Agency uses the
UF to calculate an acute or chronic reference dose (acute RfD or
chronic RfD) where the RfD is equal to the NOAEL divided by the
appropriate UF (RfD = NOAEL/UF). Where an additional safety factor is
retained due to concerns unique to the FQPA, this additional factor is
applied to the RfD by dividing the RfD by such additional factor. The
acute or chronic Population Adjusted Dose (aPAD or cPAD) is a
modification of the RfD to accommodate this type of FQPA Safety Factor.
    For non-dietary risk assessments (other than cancer) the UF is used
to determine the LOC. For example, when 100 is the appropriate UF (10X
to account for interspecies differences and 10X for intraspecies
differences) the LOC is 100. To estimate risk, a ratio of the NOAEL to
exposures (margin of exposure (MOE) = NOAEL/exposure) is calculated and
compared to the LOC.
    The linear default risk methodology (Q*) is the primary method
currently used by the Agency to quantify carcinogenic risk. The Q*
approach assumes that any amount of exposure will lead to some degree
of cancer risk. A Q* is calculated and used to estimate risk which
represents a probability of occurrence of additional cancer cases
(e.g., risk is expressed as 1 x 10-6 or one in a
million). Under certain specific circumstances, MOE calculations will
be used for the carcinogenic risk assessment. In this non-linear
approach, a ``point of departure'' is identified below which
carcinogenic effects are not expected. The point of departure is
typically a NOAEL based on an endpoint related to cancer effects though
it may be a different value derived from the dose response curve. To
estimate risk, a ratio of the point of departure to exposure
(MOEcancer = point of departure/exposures) is calculated. A
summary of the toxicological endpoints for imazethapyr used for human
risk assessment is shown in the following Table 2:
Table 2.--Summary of Toxicological Dose and Endpoints for Imazethapyr for Use in Human Risk Assessment
Exposure Scenario
Dose Used in Risk Assessment,
UF*
FQPA SF* and Level of Concern for
Risk Assessment1
Study and Toxicological Effects
Acute Dietary for general population
and females 13–50
None N/A No hazard has been identified. Quantitation of acute dietary risk is not required for both general population and female 13–50 years old population sub group.
Chronic Dietary all populations NOAEL = 250 mg/kg/day
UF = 100
cRfD = 2.5 mg/kg/day
FQPA SF= 1
cPAD = 2.5 mg/kg/day
Chronic Oral Toxicity [diet] - dog
No toxicity was seen at the HDT of 250 mg/
kg/day.
Incidental Oral Short-Term
(1–30 days) and Intermediate-
Term (30 days–6
months)
Oral NOAEL= 300 mg/kg/
day
FQPA SF= 1
LOC for MOE = 100 (residential)
Developmental Toxicity Study - rabbit
Based on ulcerations in the mucosal layer of
the stomach and the gall bladder seen at
1000 mg/kg/day (LOAEL).
Dermal Short-Term (1–30
days), Intermediate-Term
(30 days–6 months), and
Long-Term (6 months-life
time)
None N/A No hazard has been identified. Quantitation
of short-, intermediate- and long-term dermal
exposure risk assessment is not required.
Inhalation, Short-Term (1–30
days) and Intermediate-
Term (30 days–6 months)
Oral NOAEL= 300 mg/kg/
day
inhalation absorption factor
100%
LOC* for MOE = 100 (residential
and occupational)
Developmental Toxicity Study - rabbit
Based on ulcerations in the mucosal layer of
the stomach and the gall bladder, increased
incidence of clinical signs during
gestation, increased abortions, and maternal
deaths seen at 1,000 mg/kg/day
(LOAEL).
Inhalation, Long-Term (6
months-life time)
Oral NOAEL= 250 mg/kg/day
inhalation absorption factor 100%
LOC for MOE = 100 (residential
and occupational)
Chronic Oral Toxicity [diet] - dog
No toxicity was seen at the HDT of 250 mg/
kg/day.
* UF = uncertainty factor, SF = Safety Factor, LOC = level of concern
1 The reference to the FQPA Safety Factor refers to any additional safety factor retained due to concerns unique to the FQPA.

C. Exposure Assessment

    1. Dietary exposure from food and feed uses. Tolerances have been
established (40 CFR 180.447) for the combined residues of imazethapyr,
its metabolite CL 288511, and its metabolite CL 182704 in or on a
variety of raw agricultural commodities. Risk assessments were
conducted by EPA to assess dietary exposures from imazethapyr in food
as follows:
    i. Acute exposure. Acute dietary risk assessments are performed for
a food-use pesticide if a toxicological study has indicated the
possibility of an effect of concern occurring as a result of a one day
or single exposure. Since there were no developmental effects and the
toxicological effects seen in the rabbit and rat developmental toxicity
studies occurred after several days of dosing or at doses above the
limit dose, acute (single dose) risk assessment for both the general
population and the female 13-50 years old population subgroup was
considered inappropriate. Therefore, an acute dietary risk assessment
was not conducted.
    ii. Chronic exposure. In conducting this chronic dietary risk
assessment the Dietary Exposure Evaluation Model (DEEM[reg]) analysis
evaluated the individual food consumption as reported by respondents in
the USDA 1989-1992 nationwide Continuing Surveys of Food Intake by
Individuals (CSFII) and accumulated exposure to the chemical for each
commodity. The following assumptions were made for the chronic exposure
assessments: The chronic dietary assessment assumed tolerance level
residues for all registered and proposed commodities excluding corn
grain (conservative corn grain residue estimate of 0.15 ppm was used).
DEEM[reg]
default processing factors and 100% crop treated were assumed
for all registered and proposed commodities.
    iii. Anticipated residue and percent crop treated information.
Section 408(b)(2)(E) authorizes EPA to use available data and
information on the anticipated residue levels of pesticide residues in
food and the actual levels of pesticide chemicals that have been
measured in food. If EPA relies on such information, EPA must require
that data be provided 5 years after the tolerance is established,
modified, or left in effect, demonstrating that the levels in food are
not above the levels anticipated. Following the initial data
submission, EPA is authorized to require similar data on a time frame
it deems appropriate. As required by section 408(b)(2)(E), EPA will
issue a data call-in for information relating to anticipated residues
to be submitted no later than 5 years from the date of issuance of this
tolerance.
    2. Dietary exposure from drinking water. The Agency lacks
sufficient monitoring exposure data to complete a comprehensive dietary
exposure analysis and risk assessment for imazethapyr in drinking
water. Because the Agency does not have comprehensive monitoring data,
drinking water concentration estimates are made by reliance on
simulation or modeling taking into account data on the physical
characteristics of imazethapyr.
    EPA determined that the residue of concern in drinking water is
only imazethapyr. EPA provided ground (SCI-GROW; 8.97 [mu]g/l) and
surface water (rice paddy model; peak and average - 93.18 [mu]g/l)
estimated environmental concentrations (EECs) for imazethapyr. The
ground and surface water EECs were generated assuming a single
application of imazethapyr at 0.094 lbs ae/acre (highest registered/
proposed single application rate).
    Since the models used are considered to be screening tools in the
risk assessment process, the Agency does not use EECs from these models
to quantify drinking water exposure and risk as a %RfD or %PAD.
Instead, drinking water levels of comparison (DWLOCs) are calculated
and used as a point of comparison against the model estimates of a
pesticide's concentration in water. DWLOCs are theoretical upper limits
on a pesticide's concentration in drinking water in light of total
aggregate exposure to a pesticide in food, and from residential uses.
Since DWLOCs address total aggregate exposure to imazethapyr they are
further discussed in the aggregate risk sections in Unit IV.E. of this
preamble.
    Based on the rice paddy and SCI-GROW models the EECs of imazethapyr
for chronic exposures are estimated to be 93.18 [mu]g/L (parts per
billion (ppb)) for surface water and 8.97 [mu]g/L (ppb) for ground
water. Because the Agency determined that an acute (single dose) risk
assessment for both the general
population and the female 13-50 years old population subgroup was
considered inappropriate (see unit III. C.1.i.), EECs of imazethapyr
for acute exposures were not estimated.
    3. From non-dietary exposure. The term ``residential exposure'' is
used in this document to refer to non-occupational, non-dietary
exposure (e.g., for lawn and garden pest control, indoor pest control,
termiticides, and flea and tick control on pets).
    Imazethapyr is not registered for use on any sites that would
result in residential exposure.
    4. Cumulative exposure to substances with a common mechanism of
toxicity. Section 408(b)(2)(D)(v) requires that, when considering
whether to establish, modify, or revoke a tolerance, the Agency
consider ``available information'' concerning the cumulative effects of
a particular pesticide's residues and ``other substances that have a
common mechanism of toxicity.''
    EPA does not have, at this time, available data to determine
whether imazethapyr has a common mechanism of toxicity with other
substances or how to include this pesticide in a cumulative risk
assessment. Unlike other pesticides for which EPA has followed a
cumulative risk approach based on a common mechanism of toxicity,
imazethapyr does not appear to produce a toxic metabolite produced by
other substances. For the purposes of this tolerance action, therefore,
EPA has not assumed that imazethapyr has a common mechanism of toxicity
with other substances.
    EPA has recently developed a framework that it proposes to use for
conducting cumulative risk assessments on substances that have a common
mechanism of toxicity. This guidance was issued for public comment on
January 16, 2002 (67 FR 2210-2214) and is available from the OPP
Website at: http://www.epa.gov/pesticides/trac/science/cumulative--
guidance.pdf. Before undertaking a cumulative risk assessment, the
Agencv will follow procedures for identifying chemicals that have a
common mechanism of toxicity as set forth in the ``Guidance for
Identifying Pesticide Chemicals and Other Substances that Have a Common
Mechanism of Toxicity'' (64 FR 5795-5796, February 5, 1999).

D. Safety Factor for Infants and Children

    1. In general. FFDCA section 408 provides that EPA shall apply an
additional tenfold margin of safety for infants and children in the
case of threshold effects to account for prenatal and postnatal
toxicity and the completeness of the data base on toxicity and exposure
unless EPA determines that a different margin of safety will be safe
for infants and children. Margins of safety are incorporated into EPA
risk assessments either directly through use of a margin of exposure
(MOE) analysis or through using uncertainty (safety) factors in
calculating a dose level that poses no appreciable risk to humans.
    2. Prenatal and postnatal sensitivity. EPA concluded that there is
no quantitative or qualitative evidence of increased susceptibility
following in utero exposure to imazethapyr in the rat and rabbit
developmental toxicity studies. There is no quantitative and
qualitative evidence of increased susceptibility following pre- or
postnatal exposure to imazethapyr in the 2-generation reproduction
study in rats.
    3. Conclusion. There is a complete toxicity database for
imazethapyr and exposure data are complete or are estimated based on
data that reasonably accounts for potential exposures. The FQPA SFC
concluded that the safety factor could be removed (1x) for imazethapyr
because the toxicological database is complete for FQPA assessment;
there is no indication of quantitative or qualitative increased
susceptibility of rats or rabbits to in utero and/or postnatal
exposure; a developmental neurotoxicity study is not required; and the
dietary (food and drinking water) exposure assessments will not
underestimate the potential exposures for infants and children.

E. Aggregate Risks and Determination of Safety

    To estimate total aggregate exposure to a pesticide from food,
drinking water, and residential uses, the Agency calculates DWLOCs
which are used as a point of comparison against the model estimates of
a pesticide's concentration in water (EECs). DWLOC values are not
regulatory standards for drinking water. DWLOCs are theoretical upper
limits on a pesticide's concentration in drinking water in light of
total aggregate exposure to a pesticide in food and residential uses.
In calculating a DWLOC, the Agency determines how much of the
acceptable exposure (i.e., the PAD) is available for exposure through
drinking water [e.g., allowable chronic water exposure (mg/kg/day) =
cPAD - (average food + residential exposure)]. This allowable exposure
through drinking water is used to calculate a DWLOC.
    A DWLOC will vary depending on the toxic endpoint, drinking water
consumption, and body weights. Default body weights and consumption
values as used by the USEPA are used to calculate DWLOCs: 2L/70 kg
(adult male), 2L/60 kg (adult female), and 1L/10 kg (child). Default
body weights and drinking water consumption values vary on an
individual basis. This variation will be taken into account in more
refined screening-level and quantitative drinking water exposure
assessments. Different populations will have different DWLOCs.
Generally, a DWLOC is calculated for each type of risk assessment used:
acute, short-term, intermediate-term, chronic, and cancer.
    When EECs for surface water and groundwater are less than the
calculated DWLOCs, EPA concludes with reasonable certainty that
exposures to the pesticide in drinking water (when considered along
with other sources of exposure for which EPA has reliable data) would
not result in unacceptable levels of aggregate human health risk at
this time. Because EPA considers the aggregate risk resulting from
multiple exposure pathways associated with a pesticide's uses, levels
of comparison in drinking water may vary as those uses change. If new
uses are added in the future, EPA will reassess the potential impacts
of residues of the pesticide in drinking water as a part of the
aggregate risk assessment process.
    1. Acute risk. Because no acute endpoint was identified for
imazethapyr, no acute risk is expected from acute exposures.
    2. Chronic risk. Using the exposure assumptions described in this
unit for chronic exposure, EPA has concluded that exposure to
imazethapyr from food will utilize <1% of the cPAD for the U.S.
population, <1% of the cPAD for all infants (<1 year old) and <1% of
the cPAD for children (1-12 years old). There are no residential uses
for imazethapyr that result in chronic residential exposure to
imazethapyr. In addition, there is potential for chronic dietary
exposure to imazethapyr in drinking water. After calculating DWLOCs and
comparing them to the EECs for surface and ground water, EPA does not
expect the aggregate exposure to exceed 100% of the cPAD, as shown in
the following Table 3:
Table 3.--Aggregate Risk Assessment for Chronic (Non-Cancer) Exposure to Imazethapyr
Population Subgroup
cPAD mg/kg/
day
% cPAD
(Food)
Surface
Water EEC
(ppb)
Ground
Water EEC
(ppb)
Chronic DWLOC
(ppb)
U.S. Population 2.5 <1 93.18 8.97 8.7e+04
All Infants (<1 year old) 2.5 <1 93.18 8.97 2.5e+04
Children (1–6 years old) 2.5 <1 93.18 8.97 2.5e+04
Children (7–12 years old) 2.5 <1 93.18 8.97 2.5e+04
Females (13–50 years old) 2.5 <1 93.18 8.97 7.5e+04
Males (13–19 years old) 2.5 <1 93.18 8.97 8.7e+04
Males (20+ years old) 2.5 <1 93.18 8.97 8.7e+04
Seniors (55+ years old) 2.5 <1 93.18 8.97 8.7e+04

    3. Determination of safety. Based on these risk assessments, EPA
concludes that there is a reasonable certainty that no harm will result
to the general population, and to infants and children from aggregate
exposure to imazethapyr residues.

IV. Other Considerations

A. Analytical Enforcement Methodology

    Adequate enforcement methodology (example--gas chromotography) is
available to enforce the tolerance expression. The method may be
requested from: Paul Golden, USEPA/OPP/BEAD/ACB, Environmental Science
Center, 701 Mapes Road, Fort Meade, MD 20755-5350; telephone number:
(410) 305-2960; e-mail address: golden.paul@epa.gov

B. International Residue Limits

    Codex, Canada, and Mexico do not have maximum residue limits (MRLs)
for residues of imazethapyr and CL 288511 in/on rice.

C. Conditions

    The following will be imposed as conditions of registration of
imazethapyr on rice: successful pesticide method validation (PMV) and
radiovalidation of the rice, crayfish, and livestock enforcement
methods, and submission of an acceptable crayfish residue and ruminant
feeding studies.

V. Conclusion

    Therefore, the tolerances are established for combined residues of
imazethapyr, 2-[4,5-dihydro-4-methyl-4-(1-methylethyl)-5-oxo-1H-
imidazol-2-yl]-5-ethyl-3-pyridine carboxylic acid, its metabolite CL
288511, 2-[4,5-dihydro-4-methyl-4-(1-methylethyl)-5-oxo-1H-imidazol-2-
yl]-5-(1-hydroxyethyl)-3-pyridine carboxylic acid, and its metabolite
CL 182704, 5-[1-(beta-D-glucopyranosyloxy)ethyl]-2-[4,5-dihydro-4-
methyl-4-(1-methylethyl)-5-oxo-1H-imidazol-2-yl]-3-pyridinecarboxylic
acid, in or on rice grain at 0.5 parts per million (ppm), rice straw at
0.3 ppm. In addition, a tolerance is established for combined residues
of imazethapyr and its metabolite CL 288511 in or on crayfish and meat
byproducts of cattle, goat, hog, horse, and sheep at 0.10 ppm.

VI. Objections and Hearing Requests

    Under section 408(g) of the FFDCA, as amended by the FQPA, any
person may file an objection to any aspect of this regulation and may
also request a hearing on those objections. The EPA procedural
regulations which govern the submission of objections and requests for
hearings appear in 40 CFR part 178. Although the procedures in those
regulations require some modification to reflect the amendments made to
the FFDCA by the FQPA of 1996, EPA will continue to use those
procedures, with appropriate adjustments, until the necessary
modifications can be made. The new section 408(g) provides essentially
the same process for persons to ``object'' to a regulation for an
exemption from the requirement of a tolerance issued by EPA under new
section 408(d), as was provided in the old FFDCA sections 408 and 409.
However, the period for filing objections is now 60 days, rather than
30 days.

A. What Do I Need to Do to File an Objection or Request a Hearing?

    You must file your objection or request a hearing on this
regulation in accordance with the instructions provided in this unit
and in 40 CFR part 178. To ensure proper receipt by EPA, you must
identify docket ID number OPP-2002-0189 in the subject line on the
first page of your submission. All requests must be in writing, and
must be mailed or delivered to the Hearing Clerk on or before October
28, 2002.
    1. Filing the request. Your objection must specify the specific
provisions in the regulation that you object to, and the grounds for
the objections (40 CFR 178.25). If a hearing is requested, the
objections must include a statement of the factual issues(s) on which a
hearing is requested, the requestor's contentions on such issues, and a
summary of any evidence relied upon by the objector (40 CFR 178.27).
Information submitted in connection with an objection or hearing
request may be claimed confidential by marking any part or all of that
information as CBI. Information so marked will not be disclosed except
in accordance with procedures set forth in 40 CFR part 2. A copy of the
information that does not contain CBI must be submitted for inclusion
in the public record. Information not marked confidential may be
disclosed publicly by EPA without prior notice.
    Mail your written request to: Office of the Hearing Clerk (1900C),
Environmental Protection Agency, 1200 Pennsylvania Ave., NW.,
Washington, DC 20460. You may also deliver your written request to the
Office of the Hearing Clerk in Rm. 104, Crystal Mall 2, 1921
Jefferson Davis Hwy., Arlington, VA. The Office of the Hearing Clerk is
open from 8 a.m. to 4 p.m., Monday through Friday, excluding legal
holidays. The telephone number for the Office of the Hearing Clerk is
(703) 603-0061.
    2. Tolerance fee payment. If you file an objection or request a
hearing, you must also pay the fee prescribed by 40 CFR 180.33(i) or
request a waiver of that fee pursuant to 40 CFR 180.33(m). You must
mail the fee to: EPA Headquarters Accounting Operations Branch, Office
of Pesticide Programs, P.O. Box 360277M, Pittsburgh, PA 15251. Please
identify the fee submission by labeling it ``Tolerance Petition Fees.''

    EPA is authorized to waive any fee requirement ``when in the
judgement of the Administrator such a waiver or refund is equitable and
not contrary to the purpose of this subsection.'' For additional
information regarding the waiver of these fees, you may contact James
Tompkins by phone at (703) 305-5697, by e-mail at tompkins.jim@epa.gov,
or by mailing a request for information to Mr. Tompkins at Registration
Division (7505C), Office of Pesticide Programs, Environmental
Protection Agency, 1200 Pennsylvania Ave., NW., Washington, DC 20460.
    If you would like to request a waiver of the tolerance objection
fees, you must mail your request for such a waiver to: James Hollins,
Information Resources and Services Division (7502C), Office of
Pesticide Programs, Environmental Protection Agency, 1200 Pennsylvania
Ave., NW., Washington, DC 20460.
    3. Copies for the Docket. In addition to filing an objection or
hearing request with the Hearing Clerk as described in Unit VI.A., you
should also send a copy of your request to the PIRIB for its inclusion
in the official record that is described in Unit I.B.2. Mail your
copies, identified by docket ID number OPP-2002-0189, to: Public
Information and Records Integrity Branch, Information Resources and
Services Division (7502C), Office of Pesticide Programs, Environmental
Protection Agency, 1200 Pennsylvania Ave., NW., Washington, DC 20460.
In person or by courier, bring a copy to the location of the PIRIB
described in Unit I.B.2. You may also send an electronic copy of your
request via e-mail to: opp-docket@epa.gov. Please use an ASCII file
format and avoid the use of special characters and any form of
encryption. Copies of electronic objections and hearing requests will
also be accepted on disks in WordPerfect 6.1/8.0 or ASCII file format.
Do not include any CBI in your electronic copy. You may also submit an
electronic copy of your request at many Federal Depository Libraries.

B. When Will the Agency Grant a Request for a Hearing?

    A request for a hearing will be granted if the Administrator
determines that the material submitted shows the following: There is a
genuine and substantial issue of fact; there is a reasonable
possibility that available evidence identified by the requestor would,
if established resolve one or more of such issues in favor of the
requestor, taking into account uncontested claims or facts to the
contrary; and resolution of the factual issues(s) in the manner sought
by the requestor would be adequate to justify the action requested (40
CFR 178.32).

VII. Regulatory Assessment Requirements

    This final rule establishes a tolerance under FFDCA section 408(d)
in response to a petition submitted to the Agency. The Office of
Management and Budget (OMB) has exempted these types of actions from
review under Executive Order 12866, entitled Regulatory Planning and
Review (58 FR 51735, October 4, 1993). Because this rule has been
exempted from review under Executive Order 12866 due to its lack of
significance, this rule is not subject to Executive Order 13211,
Actions Concerning Regulations That Significantly Affect Energy Supply,
Distribution, or Use (66 FR 28355, May 22, 2001). This final rule does
not contain any information collections subject to OMB approval under
the Paperwork Reduction Act (PRA), 44 U.S.C. 3501 et seq., or impose
any enforceable duty or contain any unfunded mandate as described under
Title II of the Unfunded Mandates Reform Act of 1995 (UMRA) (Public Law
104-4). Nor does it require any special considerations under Executive
Order 12898, entitled Federal Actions to Address Environmental Justice
in Minority Populations and Low-Income Populations (59 FR 7629,
February 16, 1994); or OMB review or any Agency action under Executive
Order 13045, entitled Protection of Children from Environmental Health
Risks and Safety Risks (62 FR 19885, April 23, 1997). This action does
not involve any technical standards that would require Agency
consideration of voluntary consensus standards pursuant to section
12(d) of the National Technology Transfer and Advancement Act of 1995
(NTTAA), Public Law 104-113, section 12(d) (15 U.S.C. 272 note). Since
tolerances and exemptions that are established on the basis of a
petition under FFDCA section 408(d), such as the tolerance in this
final rule, do not require the issuance of a proposed rule, the
requirements of the Regulatory Flexibility Act (RFA) (5 U.S.C. 601 et
seq.) do not apply. In addition, the Agency has determined that this
action will not have a substantial direct effect on States, on the
relationship between the national government and the States, or on the
distribution of power and responsibilities among the various levels of
government, as specified in Executive Order 13132, entitled Federalism
(64 FR 43255, August 10, 1999). Executive Order 13132 requires EPA to
develop an accountable process to ensure ``meaningful and timely input
by State and local officials in the development of regulatory policies
that have federalism implications.'' ``Policies that have federalism
implications'' is defined in the Executive order to include regulations
that have ``substantial direct effects on the States, on the
relationship between the national government and the States, or on the
distribution of power and responsibilities among the various levels of
government.'' This final rule directly regulates growers, food
processors, food handlers and food retailers, not States. This action
does not alter the relationships or distribution of power and
responsibilities established by Congress in the preemption provisions
of FFDCA section 408(n)(4). For these same reasons, the Agency has
determined that this rule does not have any ``tribal implications'' as
described in Executive Order 13175, entitled Consultation and
Coordination with Indian Tribal Governments (65 FR 67249, November 6,
2000). Executive Order 13175, requires EPA to develop an accountable
process to ensure ``meaningful and timely input by tribal officials in
the development of regulatory policies that have tribal implications.''
``Policies that have tribal implications'' is defined in the Executive
order to include regulations that have ``substantial direct effects on
one or more Indian tribes, on the relationship between the Federal
Government and the Indian tribes, or on the distribution of power and
responsibilities between the Federal Government and Indian tribes.''
This rule will not have substantial direct effects on tribal
governments, on the relationship between the Federal Government and
Indian tribes, or on the distribution of power and responsibilities
between the Federal Government and Indian tribes, as specified in
Executive Order 13175. Thus, Executive Order 13175 does not apply to
this rule.

VIII. Submission to Congress and the Comptroller General

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

List of Subjects in 40 CFR Part 180

    Environmental protection, Administrative practice and procedure,
Agricultural commodities, Pesticides and pests, Reporting and
recordkeeping requirements.

    Dated: August 21, 2002.
Debra Edwards,
Acting Director, Registration Division, Office of Pesticide Programs.

    Therefore, 40 CFR chapter I is amended as follows:

PART 180--[AMENDED]

    1. The authority citation for part 180 continues to read as
follows:

    Authority: 21 U.S.C. 321(q), 346(a) and 371.

    2. Section 180.447 is revised to read as follows:


Sec. 180.447  Imazethapyr; tolerances for residues.

    (a) General. (1) Tolerances are established for residues of the
herbicide imazethapyr, 2-[4,5-dihydro-4-methyl-4-(1-methylethyl)-5-oxo-
1H-imidazol-2-yl]-5-ethyl-3-pyridine carboxylic acid, applied as its
acid or ammonium salt, in or on the following raw agricultural
commodities:

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

                                                              Commodity

------------------------------------------------------------------------
Legume vegetables..........................................          0.1
Soybeans...................................................          0.1
------------------------------------------------------------------------

    (2)Tolerances are established for the sum of the residues of the
herbicide imazethapyr, 2-[4,5-dihydro-4-methyl-4-(1-methylethyl)-5-oxo-
1H-imidazol-2-yl]-5-ethyl-3-pyridine carboxylic acid; its metabolite CL
288511, 2-[4,5-dihydro-4-methyl-4-(1-methylethyl)-5-oxo-1H-imidazol-2-
yl]-5-(1-hydroxyethyl)-3-pyridine carboxylic acid; and its metabolite
CL 182704, 5-[1-(beta-D-glucopyranosyloxy)ethyl]-2-[4,5-dihydro-4-
methyl-4-(1-methylethyl)-5-oxo-1H-imidazol-2-yl]-3-pyridinecarboxylic
acid, applied as its acid or ammonium salt, in or on the following
commodities:

------------------------------------------------------------------------
                                                              Parts per
                         Commodity                             million
------------------------------------------------------------------------
Alfalfa, forage............................................          3.0
Alfalfa, hay...............................................          3.0
Peanut.....................................................          0.1
Rice, bran.................................................          1.2
Rice, grain................................................         0.20
Rice, straw................................................         0.15
------------------------------------------------------------------------

    (3) A tolerance is established for the sum of residues of the
herbicide imazethapyr, 2-[4,5-dihydro-4-methyl-4-(1-methylethyl)-5-oxo-
1H-imidazol-2-yl]-5-ethyl-3-pyridine carboxylic acid, and its
metabolite CL 288511, 2-[4,5-dihydro-4-methyl-4-(1-methylethyl)-5- oxo-
1H-imidazol-2-yl]-5-(1-hydroxyethyl)-3-pyridine carboxylic acid,
applied as its acid or ammonium salt, in or on the following
commodities:

------------------------------------------------------------------------
                                                              Parts per
                         Commodity                             million
------------------------------------------------------------------------
Cattle, meat byproducts....................................         0.10
Corn, field, forage........................................          0.1
Corn, field, grain.........................................          0.1
Corn, field, stover........................................          0.1
Crayfish...................................................         0.10
Goat, meat byproducts......................................         0.10
Hog, meat byproducts.......................................         0.10
Horse, meat byproducts.....................................         0.10
Sheep, meat byproducts.....................................         0.10
------------------------------------------------------------------------

    (b) Section 18 emergency exemptions. [Reserved]
    (c) Tolerances with regional registrations. Tolerances with
regional registration, as defined in Sec. 180.1(n) of this chapter, are
established for the sum of residues of the herbicide imazethapyr, 2-
[4,5-dihydro-4-methyl-4-(1-methylethyl)-5-oxo-1H-imidazol-2-yl]-5-
ethyl- 3-pyridine carboxylic acid, as its ammonium salt, and its
metabolite, 2- [4,5-dihydro-4-methyl-4-(1-methylethyl)-5-oxo-1H-
imidazol-2-yl]-5-(1- hydroxyethyl)-3-pyridine carboxylic acid, both
free and conjugated, applied as its acid or ammonium salt, in or on the
following raw agricultural commodities:

------------------------------------------------------------------------
                                                              Parts per
                         Commodity                             million
------------------------------------------------------------------------
Endive (escorole)..........................................          0.1
Lettuce, head..............................................          0.1
Lettuce, leaf..............................................          0.1
------------------------------------------------------------------------

    (d) Indirect or inadvertent residues. [Reserved]
[FR Doc. 02-22093 Filed 8-28-02; 8:45 am]