[Federal Register Volume 66, Number 50 (Wednesday, March 14, 2001)]
[Rules and Regulations]
[Pages 14846-14852]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 01-6329]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 180

[OPP-301108; FRL-6774-9]
RIN 2070-AB78


Imazethapyr; Time-Limited Pesticide Tolerance

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

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SUMMARY: This regulation establishes time-limited tolerances for the 
combined residues of imazethapyr, as its ammonium salt, and its 
metabolite in or on rice, grain; rice, straw; rice hulls, and rice, 
bran. BASF requested this tolerance under the Federal Food, Drug, and 
Cosmetic Act (FFDC), as amended by the Food Quality Protection Act 
(FQPA) of 1996. These tolerances will expire on January 1, 2003.

DATES: This regulation is effective March 14, 2001. Objections and 
requests for hearings, identified by docket control number OPP-301108, 
must be received by EPA on or before May 14, 2001.

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 control number OPP-301108 in the 
subject line on the first page of your response.

FOR FURTHER INFORMATION CONTACT: By mail: Daniel J. Rosenblatt, 
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: 
[email protected].

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
           Categories                 NAICS Codes         Potentially
                                                      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.
    2. In person. The Agency has established an official record for 
this action under docket control number OPP-301108. 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

[[Page 14847]]

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 FFDCA, 21 
U.S.C. 346a as amended by the FQPA of 1996 (Public Law 104-170) 
announcing the filing of a pesticide petition (PP OF6186) for tolerance 
by American Cyanamid. This company has now merged with BASF 
Corporation. This notice included a summary of the petition prepared by 
American Cyanamid, the initial 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 the 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 its free acid or 
its ammonium salt (calculated as the acid), and its metabolite 2-[4,5-
dihydro-4-methyl-4-(1- methylethyl-5-oxo-1H-imidazol-2-yl]-5-(1-
hydroxyethyl)3-pyridinecarboxylic acid both free and conjugated in or 
on the raw agricultural commodity (RAC) rice. In this time-limited 
tolerance rule, EPA is promulgating tolerances for rice grain at 0.3 
part per million (ppm), rice straw at 0.2 ppm, rice hulls at 1.5 ppm 
and rice bran at 2.5 ppm. These tolerances will expire on January 1, 
2003. Establishing a time-limited tolerance will permit the EPA to 
evaluate confirmatory data that has not yet been fully evaluated. .
    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).

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 
imazethapyr and to make a determination on aggregate exposure, 
consistent with section 408(b)(2), for a tolerance for the 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 and 2- [4,5-
dihydro-4-methyl-4-(1-methyethyl-5-oxo-1H-imidazol-2-yl]-5-(1-
hydroxyethyl)-3-pyridine carboxylic acid (free or conjugated) on rice 
grain, rice straw, rice hulls, and rice bran. 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 the 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 and 2-[4,5-
dihydro- 4-methyl-4-(1-methyethyl-5-oxo-1H-imidazol-2-yl]-5-(1-
hydroxyethyl)-3-pyridine carboxylic acid (free or conjugated) are 
discussed below. The toxicological data considered in support of the 
proposed tolerances include:
    1. Several acute toxicology studies placing technical-grade 
imazethapyr in Toxicity Category III and Toxicity Category IV.
    2. A 1-year feeding study with dogs fed diets containing 1, 1,000, 
5,000, or 10,000 ppm with a systemic no-observed adverse effect level 
(NOAEL) of 1,000 25 milligrams/kilogram/day (mg/kg/day) based on 
decreased packed cell volume, hemoglobin, and erythrocytes in the blood 
of female dogs at the 5,000 ppm 125 mg/kg/day dose level.
    3. A 78-week carcinogenicity study in mice fed diets containing 0, 
1,000, 5,000, or 10,000 ppm (equivalent to 0, 150, 750, or 1,500 mg/kg/
day) with a systemic NOAEL of 5,000 ppm based on decreased body weight 
gain in both sexes at the 10,000 ppm dose level. No carcinogenic 
effects were observed under the conditions of the study.
    4. A 2-year chronic feeding/carcinogenicity study in rats fed diets 
containing 0, 1,000, 5,000, 10,000 ppm (equivalent to 0, 50, 250, or 
500 mg/kg/day) with no treatment-related systemic or carcinogenic 
effects observed under the conditions of the study.
    5. A multi-generation reproduction study in rats fed diets 
containing 0, 1,000, 5,000, or 10,000 ppm (equivalent to 0, 50, 250, or 
500 mg/kg/day) with no treatment-related systemic or reproductive 
effects observed under the conditions of the study.
    6. Developmental toxicity studies in rats and rabbits with no 
developmental toxicity observed under the conditions of the studies at 
dose levels up to and including the highest dose tested (HDT) (1,125 
mg/kg/day in rats and 1,000 mg/kg/day in rabbits. In the rat prenatal 
developmental study, the maternal (systemic) NOAEL was 375 mg/kg/day 
based on clinical signs of toxicity seen in dams at the LOAEL of 1,125 
mg/kg/day. The developmental (fetal) NOAEL was 1,125 mg/kg/day HDT. The 
developmental LOAEL was not established in this study. In a prenatal 
developmental study in rabbits, the maternal (systemic) NOAEL was 300 
mg/kg/day based on maternal deaths observed at the LOAEL of 1,000 mg/
kg/day HDT. The developmental (fetal) NOAEL was 1,000 mg/kg/day HDT. In 
this study, the developmental LOAEL was not established. In a 2-
generation rat reproduction study, the parental and offspring toxicity 
NOAEL was 500 mg/kg/day. The parental and offspring toxicity LOAEL was 
not established.
    7. Mutagenicity studies include gene mutation assays in bacteria 
cells (negative) and Chinese hamster ovary cells (no-dose response); 
structural chromosomal aberrations assays in vivo in rat bone marrow 
cells (negative) and in vitro in Chinese hamster ovary cells (positive 
without activation at levels toxic to cells and negative with 
activation); and other genotoxic effects (did not induce unscheduled 
DNA synthesis in rat hepatocytes cultured in vitro).

B. Toxicological Endpoints

    The dose at which the NOAEL from the toxicology study identified as

[[Page 14848]]

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 (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 1:

     Table 1.--Summary of Toxicological Dose and Endpoints for imazethapyr for Use in Human Risk Assessment
----------------------------------------------------------------------------------------------------------------
                                                                 FQPA SF* and Level of
          Exposure Scenario               Dose Used in Risk         Concern for Risk     Study and Toxicological
                                            Assessment, UF             Assessment                Effects
----------------------------------------------------------------------------------------------------------------
Acute dietary females 13-50 years of   None                     None                     A dose and endpoint
 age and general population including                                                     attributable to a
 infants and children                                                                     single exposure were
                                                                                          not identified from
                                                                                          the reviewed and
                                                                                          acceptable oral
                                                                                          toxicity studies,
                                                                                          including both
                                                                                          maternal and
                                                                                          developmental toxicity
                                                                                          in the developmental
                                                                                          toxicity studies.
----------------------------------------------------------------------------------------------------------------
Chronic dietary all populations        NOAEL = 25 mg/kg/day     FQPA SF = 10             1-year feeding study--
                                       UF = 100...............  cPAD = chronic RfD/FQPA   dog
                                       Chronic RfD = .25 mg/kg/  SF =.                   LOAEL = 125 mg/kg/day
                                        day.                    0.025 mg/kg/day........   based on decreased
                                                                                          packed cell volume,
                                                                                          hemoglobin and
                                                                                          erythrocytes seen in
                                                                                          females.
----------------------------------------------------------------------------------------------------------------
Short-term dermal (1 to 7 days), and   None                     None                     EPA concluded that no
 intermediate term dermal (1 week to                                                      hazard is identified
 several months)                                                                          to support quantifying
(Residential)........................                                                     risk for these
                                                                                          exposure scenarios.
----------------------------------------------------------------------------------------------------------------
Short-term Inhalation (1 to 7 days)    Inhalation (or oral)     LOC for MOE = 1,000      Rabbit Developmental
(Residential)........................   study                   (Residential)..........   Study
                                       NOAEL= 300 mg/kg/day                              LOAEL = 1,000 mg/kg/day
                                        (inhalation absorption                            based on maternal
                                        rate = 100%).                                     deaths seen at the
                                                                                          HDT.
----------------------------------------------------------------------------------------------------------------
Intermediate-Term Inhalation (1 week   Inhalation (or oral)     LOC for MOE = 1,000      Rabbit Developmental
 to several months)                     study                    (Residential)            Study
(Residential)........................  NOAEL = 300 mg/kg/day                             LOAEL = 1,000 mg/kg/day
                                        (inhalation absorption                            based on maternal
                                        rate = 100%).                                     deaths seen at the
                                                                                          HDT.
----------------------------------------------------------------------------------------------------------------
Cancer (oral, dermal, inhalation)      EPA determined that a                             Rat and mouse
                                        cancer risk assessment                            carcinogenicity
                                        is not necessary.                                 studies were negative
                                                                                          for carcinogenicity.
----------------------------------------------------------------------------------------------------------------
 * 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 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, in or on a variety of raw agricultural commodities 
including legume vegetables, soybeans, alfalfa, peanuts, corn grain, 
endive, and lettuce. Risk assessments were conducted by EPA to assess 
dietary exposures from combined residues of imazethapyr in food as 
follows:
     i. Acute exposure. Acute dietary risk assessments are performed 
for a food-use pesticide if a toxicological study has

[[Page 14849]]

indicated the possibility of an effect of concern occurring as a result 
of a one day or single exposure. EPA did not perform a quantified acute 
dietary risk assessment. In acceptable toxicity studies, no appropriate 
endpoint was identified for this exposure duration.
     ii. Chronic exposure. In conducting this chronic dietary risk 
assessment the Dietary Exposure Evaluation Model (DEEM\TM\) 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 exposure assessment that supports this time-limited 
tolerance is conservative. Tolerance level residues, 100 percent crop 
treated, and default processing factors were assumed for all registered 
and proposed uses. Percent crop treated estimates and anticipated 
residue assumptions were not used in this risk assessment.
    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.
    The Agency uses the Generic Estimated Environmental Concentration 
(GENEEC) or the Pesticide Root Zone/Exposure Analysis Modeling System 
(PRZM/EXAMS) to estimate pesticide concentrations in surface water and 
SCI-GROW, which predicts pesticide concentrations in groundwater. In 
general, EPA will use GENEEC (a tier 1 model) before using PRZM/EXAMS 
(a tier 2 model) for a screening-level assessment for surface water. 
The GENEEC model is a subset of the PRZM/EXAMS model that uses a 
specific high-end runoff scenario for pesticides. GENEEC incorporates a 
farm pond scenario, while PRZM/EXAMS incorporate an index reservoir 
environment in place of the previous pond scenario. The PRZM/EXAMS 
model includes a percent crop area factor as an adjustment to account 
for the maximum percent crop coverage within a watershed or drainage 
basin.
    None of these models include consideration of the impact processing 
(mixing, dilution, or treatment) of raw water for distribution as 
drinking water would likely have on the removal of pesticides from the 
source water. The primary use of these models by the Agency at this 
stage is to provide a coarse screen for sorting out pesticides for 
which it is highly unlikely that drinking water concentrations would 
ever exceed human health levels of concern.
    Since the models used are considered to be screening tools in the 
risk assessment process, the Agency does not use estimated 
environmental concentrations (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 below.
    Based on the GENEEC and SCI-GROW models the estimated environmental 
concentrations (EECs) of imazethapyr for acute exposures are estimated 
to be 6.34 parts per billion (ppb) for surface water and 2.2 ppb for 
ground water. The EECs for chronic exposures are estimated to be 6.13 
ppb for surface water and 2.2 ppb for ground water.
    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. For information regarding EPA's efforts to 
determine which chemicals have a common mechanism of toxicity and to 
evaluate the cumulative effects of such chemicals, see the final rule 
for Bifenthrin Pesticide Tolerances (62 FR 62961, November 26, 1997).

D. Safety Factor for Infants and Children

    1. In general. FFDCA section 408 provides that EPA shall apply an 
additional ten-fold 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. The pre- and postnatal 
toxicology data base for imazethapyr is complete. There is no evidence 
of increased susceptibility to infants and children.
    3. Conclusion. There is a complete toxicity data base for 
imazethapyr and exposure data are complete or are estimated based on 
data that reasonably accounts for potential exposures. There is no 
evidence of qualitative or quantitative susceptibility to infants and 
children. No evidence of increased susceptibility was observed in rat 
and rabbit fetuses following in utero exposure in the prenatal 
developmental toxicity study and also in the 2-generation reproduction 
study in rats. However, EPA has not concluded its review process 
regarding application of the additional safety factor for infants and 
children as to imazethapyr and, therefore, for the purpose of this 
action will retain the statutory default factor of an additional 10x. 
Once EPA has the opportunity to complete its review of the data on 
imazethapyr in this area, the 10x safety factor may be reduced or 
removed.

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

[[Page 14850]]

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 Office of Water are used to calculate 
DWLOCs: 2Liter (L)/70 kilogram (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, OPP concludes with reasonable certainty that 
exposures to the pesticide in drinking water (when considered along 
with other sources of exposure for which OPP has reliable data) would 
not result in unacceptable levels of aggregate human health risk at 
this time. Because OPP 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, OPP 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. EPA did not select a toxicological endpoint for this 
exposure duration. A dose and endpoint attributable to a single 
exposure were not identified from oral toxicity studies. Therefore, no 
quantified acute risk assessment is necessary.
    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, 3% of the cPAD for All Infants (1 year) and 3% of the cPAD 
for Children (1-6 years). There are no residential uses for imazethapyr 
that result in chronic residential exposure to imazethapyr. 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 2:

                                  Table 2.-- Aggregate Risk Assessment for Chronic (Non-Cancer) Exposure to imazethapyr
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                       Surface Water EEC
        Population Subgroup              cPAD mg/kg/day           % cPAD (Food)        parts per billion       Ground Water EEC     Chronic DWLOC (ppb)
                                                                                             (ppb)                  (ppb)
--------------------------------------------------------------------------------------------------------------------------------------------------------
U.S. Population                      0.025                   1                       6.13                   2.2                    864
All Infants (<1 year)                0.025                   3                       6.13                   2.2                    242
Children (1-6 years)                 0.025                   3                       6.13                   2.2                    243
 Females (13-50 years)               0.025                   1                       6.13                   2.2                    743
--------------------------------------------------------------------------------------------------------------------------------------------------------

    3. Short-term risk. Short-term aggregate exposure takes into 
account residential exposure plus chronic exposure to food and water 
(considered to be a background exposure level).
    Imazethapyr is not registered for use on any sites that would 
result in residential exposure. Therefore, the aggregate risk is the 
sum of the risk from food and water, which do not exceed the Agency's 
level of concern.
    4. Intermediate-term risk. Intermediate-term aggregate exposure 
takes into account residential exposure plus chronic exposure to food 
and water (considered to be a background exposure level).
    Imazethapyr is not registered for use on any sites that would 
result in residential exposure. Therefore, the aggregate risk is the 
sum of the risk from food and water, which do not exceed the Agency's 
level of concern.
    5. Aggregate cancer risk for U.S. population. The rat and mouse 
carcinogenicity studies were negative for carcinogenicity. In light of 
these results, EPA determined that a quantified aggregate cancer risk 
assessment is not necessary.
    6. 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

    Analytical enforcement methods for the purpose of enforcing 
previously established tolerances for imazethapyr have been published 
in the Pesticide Analytical Manual Vol-II (PAM-II). CE Determinative 
and LC/MS methods for the enforcement of the time-limited tolerances 
for rice have been proposed by the registrant. Independent laboratory 
validation of these methods have been submitted to EPA. Prior to 
publication in PAM-II, and upon request, the analytical methods for the 
rice commodities will be available from the Analytical Chemistry Branch 
(ACB), BEAD (7503C), Environmental Science Center, 701 Mapes Rd., Fort 
George G. Meade, MD 20755-5350; contact Francis D. Griffith, Jr.; 
telephone number: (410) 305-2905; e-mail [email protected]. The 
Analytical standards for this method are also available from the EPA 
National Pesticide Standard Repository at the same location.

B. International Residue Limits

    This time-limited tolerance action is not incompatible with that 
taken by Codex, Canada, or Mexico as there are no established 
tolerances by those entities for imazethapyr on rice.

C. Conditions

    Based on confined rotational crop data, crop rotational intervals 
of 4 months for wheat and 9.5 months for field corn are necessary. A 
45-day pre harvest interval is required.

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) and 2-[4,5-dihydro-
4-methyl-4-(1-

[[Page 14851]]

methylethyl-5-oxo-1H-imidazole-2-yl]-5-(1-hdroxyethyl)-3-pyridine 
carboxylic acid (free or conjugated), in or on rice grain, rice straw, 
rice hulls, and rice bran.

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 control number OPP-301108 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 May 14, 
2001.
    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 (1900), 
Environmental Protection Agency, 1200 Pennsylvania Ave., NW., 
Washington, DC 20460. You may also deliver your request to the Office 
of the Hearing Clerk in Rm. C400, Waterside Mall, 401 M St., SW., 
Washington, DC 20460. 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 (202) 260-4865.
    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 [email protected], 
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 control number OPP-301108, 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: [email protected]. 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). 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,

[[Page 14852]]

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, 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: March 1, 2001.
  James Jones,
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 amended as follows:
    i. By adding a heading to paragraph (a), designating the text 
following the heading as paragraph (a)(1), and alphabetically adding 
commodities to the table in newly designated paragraph (a)(1);
    ii. By redesignating paragraphs (b) and (c) as paragraphs (a)(2) 
and (a)(3);
    iii. By adding and reserving new paragraphs (b) and (c); and
    iv. By adding a heading to paragraph (d).
    The additions read as follows:


Sec. 180.447  Imazethapyr, ammonium salt; tolerance for residues.

    (a) General. (1)  *  *  *

------------------------------------------------------------------------
                                                          Expiration/
            Commodity             Parts per  million    Revocation Date
------------------------------------------------------------------------
               *    *    *      *      *      *    *
Rice, bran                        2.5                 1/1/03
Rice, grain                       0.30                1/1/03
Rice, hulls                       1.5                 1/1/03
Rice, straw                       0.20                1/1/03
               *    *    *      *      *      *    *
------------------------------------------------------------------------

* * * * *
    (b) Section 18 emergency exemptions. [Reserved]
    (c) Tolerances with regional registrations. [Reserved]
    (d) Indirect or inadvertent residues.  * * *

[FR Doc. 01-6329 Filed 3-13-01; 8:45 am]
BILLING CODE 6560-50-S