[Federal Register Volume 69, Number 102 (Wednesday, May 26, 2004)]
[Rules and Regulations]
[Pages 29882-29890]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 04-11561]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 180

[OPP-2004-0093; FRL-7355-8]


Isoxadifen-Ethyl; Pesticide Tolerance

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

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SUMMARY: This regulation establishes three tolerances for the combined 
residues of the herbicide safener isoxadifen-ethyl in or on rice, 
grain; rice, straw; and rice, hulls. Bayer CropScience (formerly 
Aventis CropScience) requested this tolerance under the Federal Food, 
Drug, and Cosmetic Act (FFDCA), as amended by the Food Quality 
Protection Act of 1996 (FQPA).

DATES: This regulation is effective May 26, 2004. Objections and 
requests for hearings must be received on or before July 26, 2004.

ADDRESSES: To submit a written objection or hearing request follow the 
detailed instructions as provided in Unit VI. of the SUPPLEMENTARY 
INFORMATION. EPA has established a docket for this action under Docket 
ID number OPP-2004-0093. All documents in the docket are listed in the 
EDOCKET index at http://www.epa.gov/edocket. Although listed in the 
index, some information is not publicly available, i.e., Confidential 
Business Information (CBI) or other information whose disclosure is 
restricted by statute. Certain other material, such as copyrighted 
material, is not placed on the Internet and will be publicly available 
only in hard copy form. Publicly available docket materials are 
available either electronically in EDOCKET or in hard copy at the 
Public Information and Records Integrity Branch (PIRIB), Rm. 119, 
Crystal Mall 2, 1921 Jefferson Davis Hwy., Arlington, VA. This 
docket facility is open from 8:30 a.m. to 4 p.m., Monday through 
Friday, excluding legal holidays. The docket telephone number is (703) 
305-5805.

FOR FURTHER INFORMATION CONTACT:  James Parker, Registration Division

[[Page 29883]]

(7505C), Office of Pesticide Programs, Environmental Protection Agency, 
1200 Pennsylvania Ave., NW., Washington, DC 20460-0001; telephone 
number: (703) 308-0371; e-mail address: [email protected].

SUPPLEMENTARY INFORMATION:

I. General Information

A. Does this Action Apply to Me?

    You may be potentially affected by this action if you are an 
agricultural producer, food manufacturer, or pesticide manufacturer. 
Potentially affected entities may include, but are not limited to:
     Crop production (NAICS 111), e.g., agricultural workers; 
greenhouse, nursery, and floriculture workers; farmers.
     Animal production (NAICS 112), e.g., cattle ranchers and 
farmers, dairy cattle farmers, livestock farmers.
     Food manufacturing (NAICS 311), e.g., agricultural 
workers; farmers; greenhouse, nursery, and floriculture workers; 
ranchers; pesticide applicators.
     Pesticide manufacturing (NAICS 32532), e.g., agricultural 
workers; commercial applicators; farmers; greenhouse, nursery, and 
floriculture workers; residential users.
    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 this unit could also be 
affected. The North American Industrial Classification System (NAICS) 
codes have been provided to assist you and others in determining 
whether this action might apply to certain entities. If you have any 
questions regarding the applicability of this action to a particular 
entity, consult the person listed under FOR FURTHER INFORMATION 
CONTACT.

B. How Can I Access Electronic Copies of this Document and Other 
Related Information?

    In addition to using EDOCKET (http://www.epa.gov/edocket/), you may 
access this Federal Register document electronically through the EPA 
Internet under the ``Federal Register'' listings at http://www.epa.gov/fedrgstr/. A frequently updated electronic version of 40 CFR part 180 
is available at E-CFR Beta Site Two at http://www.gpoaccess.gov/ecfr/.

II. Background and Statutory Findings

    In the Federal Registers of June 9, 1999 (64 FR 30997) (FRL-6082-
6), and June 30, 2000 (65 FR 40632) (FRL-6592-6), EPA issued notices 
pursuant to section 408(d)(3) of FFDCA, 21 U.S.C. 346a(d)(3), 
announcing the filing of a pesticide petition (PP 9E5060) by Aventis 
CropScience, formerly AgrEvo USA, now doing business as Bayer 
CropScience, P.O. Box 12014, 2 T.W. Alexander Drive, Research Triangle 
Park, NC 27709. That notice included a summary of the petition prepared 
by the petitioner.
    The petition requested that 40 CFR 180.570 be amended by 
establishing tolerances for the combined residues of the herbicide 
safener isoxadifen-ethyl, (ethyl 5,5-diphenyl-2-isoxazoline-3-
carboxylate) (CAS No. 163520-33-0) and its metabolites: 4,5-dihydro-
5,5-diphenyl-3-isoxazolecarboxylic acid and [beta]-hydroxy-[beta]-
benezenepropanenitrile, in or on the following rice commodities: rice, 
grain; rice, straw; rice hulls; and rice bran at 0.10, 0.25, 0.50, and 
0.80 parts per million (ppm), respectively. There were no comments 
received in response to the notice of filing.
    In the Federal Register of June 21, 2001 (66 FR 33179) (FRL-6786-
1), EPA established time-limited tolerances (expiring June 21, 2004) 
for isoxadifen-ethyl in or on rice commodities. Submission of the 
following data was required: Confined/field accumulation in rotational 
crops study; rice processed commodity study; successful petition method 
validation of the analytical enforcement method; and adequate storage 
stability data.
    Section 408(b)(2)(A)(i) of 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) of FFDCA 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) of FFDCA 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 of FFDCA 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) of FFDCA, 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) of FFDCA, for a tolerance for combined residues of 
isoxadifen-ethyl (CAS No. 163520-33-0) and its metabolites: 4,5-
dihydro-5,5-diphenyl-3-isoxazolecarboxylic acid and [beta]-hydroxy-
[beta]-benezenepropanenitrile on rice commodities. 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 isoxadifen ethyl as 
well as the no observed adverse effect level (NOAEL) and the lowest 
observed adverse effect level (LOAEL) from the toxicity studies 
reviewed by the Agency are discussed in the Federal Register of June 
21, 2001 (66 FR 33179) (FRL-6786-1). At that time the Agency considered 
the toxicity database to be complete. No additional toxicity studies 
have been submitted by the petitioner.

B. Toxicological Endpoints

    The dose at which 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 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 
intraspecies differences.
    Three other types of safety or uncertainty factors may be used: 
``Traditional uncertainty factors;'' the ``special FQPA safety 
factor;'' and the

[[Page 29884]]

``default FQPA safety factor.'' By the term ``traditional uncertainty 
factor,'' EPA is referring to those additional uncertainty factors used 
prior to FQPA passage to account for database deficiencies. These 
traditional uncertainty factors have been incorporated by the FQPA into 
the additional safety factor for the protection of infants and 
children. The term ``special FQPA safety factor'' refers to those 
safety factors that are deemed necessary for the protection of infants 
and children primarily as a result of the FQPA. The ``default FQPA 
safety factor'' is the additional 10X safety factor that is mandated by 
the statute unless it is decided that there are reliable data to choose 
a different additional factor (potentially a traditional uncertainty 
factor or a special FQPA safety factor).
    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 an UF of 
100 to account for interspecies and intraspecies differences and any 
traditional uncertainty factors deemed appropriate (RfD = NOAEL/UF). 
Where a special FQPA safety factor or the default FQPA safety factor is 
used, 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 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.
    A summary of the toxicological endpoints for isoxadifen-ethyl used 
for human risk assessment is shown in Table 1. of this unit:

   Table 1.--Summary of Toxicological Dose and Endpoints for Isoxadifen-ethyl for Use in Human Risk Assessment
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                                          Dose Used in Risk
                                             Assessment,
          Exposure Scenario                Interspecies and     Special FQPA SF and LOC  Study and Toxicological
                                         Intraspecies and any     for Risk Assessment            Effects
                                            Traditional UF
----------------------------------------------------------------------------------------------------------------
Acute dietary (females 13-50 years of  NOAEL = 15 milligrams/   Special FQPA SF = 1X     Rat developmental study
 age)                                   kilograms/day (mg/kg/   aPAD = acute RfD /       LOAEL = 120 mg/kg/day
                                        day)                     Special FQPA SF = 0.15   based on bent scapula
                                       UF = 100...............   mg/kg/day.               in rat fetuses
                                       Acute RfD = 0.15 mg/kg/
                                        day.
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Chronic dietary (all populations)      NOAEL = 3.3 mg/kg/day    Special FQPA SF = 1X     1-Year dog feeding
                                       UF = 100...............  cPAD = chronic RfD /      study, (co-critical)
                                       Chronic RfD = 0.033 mg/   Special FQPA SF =        90-day dog feeding
                                        kg/day.                  0.033 mg/kg/day.         study
                                                                                         LOAEL = 6.1 mg/kg/day
                                                                                          based on kidney
                                                                                          histopathology in both
                                                                                          sexes of dogs in both
                                                                                          studies
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Short-term dermal, inhalation, and     Dermal (or oral) study   LOC for MOE = <100%      90-day rat feeding
 incidental oral (1 to 7 days)          NOAEL = 13.8 mg/kg/day  (Residential)..........   study
(Residential)........................  (dermal absorption rate                           LOAEL = 137.9 mg/kg/day
                                        = 14%).                                           based on decreased
                                       (inhalation absorption                             body weight and weight
                                        rate = 100%).                                     gain at Day 8
----------------------------------------------------------------
Intermediate-term dermal, inhalation,  Dermal (or oral) study   LOC for MOE = <100%      1[dash]Year dog feeding
 and incidental oral (1 week to         NOAEL = 3.3 mg/kg/day   (Residential)..........   study (co-critical) 90-
 several months)                       (dermal absorption rate                            day dog feeding study
(Residential)........................   = 14%).                                          LOAEL = 6.1 mg/kg/day
                                       (inhalation absorption                             based on kidney
                                        rate = 100%).                                     histopathology in both
                                                                                          sexes of dogs in both
                                                                                          studies
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Cancer (oral, dermal, inhalation)      Cancer classification    Risk assessment not      No evidence of
                                        ``not likely to be a     required                 carcinogenicity
                                        human carcinogen''
----------------------------------------------------------------------------------------------------------------

C. Exposure Assessment

    1. Dietary exposure from food and feed uses. Permanent tolerances 
on corn commodities and time-limited tolerances on rice commodities are 
established (40 CFR 180.570) for the combined residues of isoxadifen-
ethyl. The time-limited tolerances will expire on June 21, 2004. To 
convert these time-limited tolerances to permanent tolerances, risk 
assessments were conducted by EPA to assess dietary exposures from 
isoxadifen-ethyl.
    At this time there is a time-limited tolerance for rice, bran at 
0.80 ppm. The Agency's review of residue chemistry data indicated that 
residues of isoxadifen-ethyl do not concentrate in rice, bran. 
Therefore, the rice, grain tolerance will cover this processed 
commodity. The existing time-limited tolerance for rice, bran is 
therefore not needed and will be removed. Hence, a permanent tolerance 
for rice, bran is not established in this final rule.
    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 1-day or 
single exposure. In conducting the acute dietary risk assessment EPA 
used the Dietary Exposure Evaluation Model software with the Food 
Commodity Intake Database (DEEM-FCID\TM\), which incorporates food 
consumption data as reported by respondents in the U.S. Department of 
Agriculture (USDA) 1994-1996 and 1998 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 acute exposure assessments: Tolerance level

[[Page 29885]]

residues, 100% crop treated and DEEM (version 7.76) default 
concentration factors for all commodities. No anticipated residues were 
used.
    The Agency estimated the acute dietary food exposure for females 
(ages 13-49 years old) to be 0.000511 mg/kg/day. The Agency's LOC for 
acute dietary risk is greater than 100% of the aPAD. When compared to 
the aPAD of 0.15 mg/kg/day for isoxadifen-ethyl, the dietary risk is 
less than 1.0% of the aPAD and therefore less than the Agency's LOC.
    ii. Chronic exposure. In conducting the chronic dietary risk 
assessment EPA used the DEEM-FCID\TM\, which incorporates food 
consumption data as reported by respondents in the USDA 1994-1996 and 
1998 nationwide CSFII, and accumulated exposure to the chemical for 
each commodity. The following assumptions were made for the chronic 
exposure assessments: Tolerance level residues, 100% crop treated and 
DEEM (version 7.76) default processing factors. No anticipated residues 
were used. The chronic dietary exposure estimates were all less than or 
equal to 1.5% of the cPAD for all population subgroups and are 
therefore less than the LOC (greater than 100% of the cPAD). The 
chronic dietary exposure estimates for representative population 
subgroups are presented below in Table 2:

                       Table 2.--Summary of Chronic Dietary Exposure for Isoxadifen-ethyl
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                           Subgroup                               Exposure (mg/kg/day)            % cPAD
----------------------------------------------------------------------------------------------------------------
U.S. population (total)                                                        0.000216                     <1.0
-----------------------------------------------------------------------------------------
All infants (<1-year old)                                                      0.000339                        1
-----------------------------------------------------------------------------------------
Children (1-2 years old)                                                       0.000427                      1.3
-----------------------------------------------------------------------------------------
Children (3-5 years old)                                                       0.000486                      1.5
-----------------------------------------------------------------------------------------
Children (6-12 years old)                                                      0.000373                      1.1
-----------------------------------------------------------------------------------------
Youth (13-19 years old)                                                        0.000294                     <1.0
-----------------------------------------------------------------------------------------
Adults (20-49 years old)                                                       0.000182                     <1.0
-----------------------------------------------------------------------------------------
Adults (50+ years old)                                                         0.000099                     <1.0
-----------------------------------------------------------------------------------------
Females (13-49 years old)                                                      0.000177                     <1.0
----------------------------------------------------------------------------------------------------------------

    iii. Cancer. After consideration of the Agency's ``Proposed 
Guidelines for Carcinogen Risk Assessment (April 10, 1996),'' EPA has 
classified isoxadifen-ethyl as ``not likely to be a human carcinogen.'' 
This classification is based on the lack of evidence of carcinogenicity 
in mice and rats. Therefore, a cancer risk analysis is not necessary.
    2. Dietary exposure from drinking water. The Agency lacks 
sufficient monitoring exposure data to complete a comprehensive dietary 
exposure analysis and risk assessment for isoxadifen-ethyl 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 isoxadifen-ethyl.
    The Agency uses the Generic Estimated Environmental Concentration 
(GENEEC) or the Pesticide Root Zone Model/Exposure Analysis Modeling 
System (PRZM/EXAMS) to estimate pesticide concentrations in surface 
water and Screening Concentration in Ground Water (SCI-GROW), which 
predicts pesticide concentrations in ground water. In general, EPA will 
use GENEEC (a Tier I model) before using PRZM/EXAMS (a Tier II 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 incorporates 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 screen for sorting out pesticides for which it is 
unlikely that drinking water concentrations would exceed human health 
LOCs.
    Since the models used are considered to be screening tools in the 
risk assessment process, the Agency does not use estimated 
environmental concentrations (EECs), which are the model estimates of a 
pesticide's concentration in water, used to quantify drinking water 
exposure and risk as a %RfD or %PAD. Instead drinking water levels of 
comparison (DWLOC) 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 isoxadifen-ethyl, they are further discussed in the 
aggregate risk sections in Unit III.E.
    Based on the GENEEC, FQPA Index Reservoir Screening Tool (FIRST) 
and SCI-GROW models, the EECs of isoxadifen-ethyl for acute exposures 
are estimated to be 80 parts per billion (ppb) for surface water and 5 
ppb for ground water. The EECs for chronic exposures are estimated to 
be 40 ppb for surface water and 5 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). The petitioner has 
requested to use isoxadifen-ethyl on turf, which could result in 
residential exposures.
    The proposed turf use is intended for professional application to 
Bermudagrass on golf courses, sod farms, residential and commercial 
site

[[Page 29886]]

lawns, parks, recreational facilities, and similar sites. It is not 
intended for use by homeowners or other non-professional applications. 
Therefore, residential mixer/loader and applicator exposures are not 
anticipated. The following short-term post-application residential 
exposures are anticipated: Adult (dermal - golf course and residential 
lawn), children (dermal - residential lawn), and toddler (dermal and 
incidental oral - residential lawn). However, dermal exposures for 
golfers are considered to be less than those resulting from a 
residential turf application, and were therefore not assessed.
    Hand to mouth (HTM), object to mouth (OTM), and soil hand to mouth 
short-term incidental oral exposures may occur as a result of the 
proposed turf use. However, the soil hand to mouth exposure is 
considered to be very small in comparison to the other exposures. MOEs 
were estimated to be 790 (for a 15 kg child) and 1,500 (for an adult). 
MOEs greater than 100 are not of concern.
    4. Cumulative effects from substances with a common mechanism of 
toxicity. Section 408(b)(2)(D)(v) of FFDCA 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.''
    Unlike other pesticides for which EPA has followed a cumulative 
risk approach based on a common mechanism of toxicity, EPA has not made 
a common mechanism of toxicity finding as to isoxadifen-ethyl and any 
other substances and isoxadifen-ethyl 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 isoxadifen-ethyl 
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 policy statements released by EPA's Office of 
Pesticide Programs concerning common mechanism determinations and 
procedures for cumulating effects from substances found to have a 
common mechanism on EPA's web site at http://www.epa.gov/pesticides/cumulative/.

D. Safety Factor for Infants and Children

    1. In general. Section 408 of FFDCA 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 database on toxicity and exposure 
unless EPA determines based on reliable data 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 
MOE analysis or through using uncertainty (safety) factors in 
calculating a dose level that poses no appreciable risk to humans. In 
applying this provision, EPA either retains the default value of 10X 
when reliable data do not support the choice of a different factor, or, 
if reliable data are available, EPA uses a different additional safety 
factor value based on the use of traditional uncertainty factors and/or 
special FQPA safety factors, as appropriate.
    2. Prenatal and postnatal sensitivity. A summary of the 
developmental toxicity studies for isoxadifen-ethyl which have been 
reviewed and evaluated by the Agency published in the Federal Register 
of June 21, 2001 (66 FR 33179) (FRL-6786-1).
    3. Conclusion. Based on the following considerations, the Agency 
concluded that the special FQPA safety factor is reduced to 1X.
     No neurotoxicity studies are available. However, no 
clinical signs of neurotoxicity were observed in the available toxicity 
studies conducted with isoxadifen-ethyl in rats, rabbits, or dogs, 
other than those neurotoxic clinical signs associated with agonal 
toxicity in these species.
     There was no evidence of enhanced susceptibility in the 
rabbit developmental study or the 2-generation rat reproduction study.
     In the developmental rat study, quantitative 
susceptibility was evidenced as increased fetal incidences of bent 
scapula at (120 mg/kg/day) a dose lower than that evoking maternal 
toxicity (mortality, reduced body weights, body weight gains, and food 
consumption at 1,000 mg/kg/day). The overall toxicity profile and the 
doses and endpoints selected for risk assessment for isoxadifen-ethyl, 
characterize the degree of concern for the effects observed in this 
study as low. There is a clear NOAEL and well-characterized dose 
response for the developmental effects observed. No residual 
uncertainties were identified. The NOAEL for developmental effects in 
this study (15 mg/kg/day) is used as the basis for the aRfD for the 
females 13-50 population subgroup. For all other toxicity endpoints 
established for isoxadifen-ethyl, a NOAEL lower than this developmental 
NOAEL is used.
     The residue chemistry and environmental fate databases are 
complete.
     The acute and chronic dietary food exposure assessments 
assumed tolerance level residues and 100% crop treated for all crops. 
Therefore dietary exposures/risks are unlikely to be underestimated.
     The drinking water assessment utilizes water concentration 
values generated by models and associated modeling parameters which are 
designed to provide conservative, health protective, high-end estimates 
of drinking water concentrations.
     The residential assessment is considered a Tier I 
assessment. Therefore residential exposures/risks are unlikely to be 
underestimated.

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 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 EPA's Office of Water are used to calculate 
DWLOCs: 2 liter (L)/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. 
For isoxadifen-ethyl DWLOCs are calculated for: Acute, short-term, and 
chronic scenarios.
    When EECs for surface water and ground water are less than the

[[Page 29887]]

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. Using the exposure assumptions previously discussed 
in this unit for acute exposure, the acute dietary exposure from food 
to isoxadifen-ethyl will occupy <1.0% of the aPAD for females ages 13 
and 50 years old. In addition, there is potential for acute dietary 
exposure to isoxadifen-ethyl in drinking water. The DWLOC is much 
greater than the EECs. Therefore, EPA does not expect acute aggregate 
exposure to exceed 100% of the aPAD, as shown in Table 3 of this unit:

                   Table 3.--Aggregate Risk Assessment for Acute Exposure to Isoxadifen-ethyl
----------------------------------------------------------------------------------------------------------------
                                                                             Surface       Ground
              Population Subgroup                 aPAD (mg/      % aPAD     Water EEC    Water EEC   Acute DWLOC
                                                     kg)         (Food)       (ppb)        (ppb)        (ppb)
----------------------------------------------------------------------------------------------------------------
Females (13-50 years old)                               0.15         <1.0           80            5        4,500
----------------------------------------------------------------------------------------------------------------

    2. Chronic risk. Using the chronic dietary exposure analysis 
discussed previously, EPA has concluded that exposure to isoxadifen-
ethyl from food will utilize <1.0% of the cPAD for the U.S. population, 
1.0% of the cPAD for all infants (<1 year old), and 1.5% of the cPAD 
for children 3-5 years old. Based on the use pattern, chronic 
residential exposure to residues of isoxadifen-ethyl is not expected. 
But, there is potential for chronic dietary exposure to isoxadifen-
ethyl in drinking water. For each population subgroup, the DWLOC is 
much greater than the estimated EEC. Therefore, EPA does not expect the 
aggregate exposure to exceed 100% of the cPAD. Thus, there is no 
concern for chronic aggregate exposure to isoxadifen-ethyl, as shown in 
Table 4. below:

            Table 4.--Aggregate Risk Assessment for Chronic (Non-Cancer) Exposure to isoxadifen-ethyl
----------------------------------------------------------------------------------------------------------------
                                                                             Surface       Ground
              Population Subgroup                cPAD mg/kg/     % cPAD     Water EEC    Water EEC     Chronic
                                                     day         (Food)       (ppb)        (ppb)     DWLOC (ppb)
----------------------------------------------------------------------------------------------------------------
U.S. population                                        0.033         <1.0           40            5        1,100
--------------------------------------------------------------
All infants (< 1 year old)                             0.033          1.0           40            5          330
--------------------------------------------------------------
Children (1-2 years old)                               0.033          1.3           40            5          330
--------------------------------------------------------------
Children (3-5 years old)                               0.033          1.5           40            5          330
--------------------------------------------------------------
Children (6-12 years old)                              0.033          1.1           40            5          330
--------------------------------------------------------------
Youth (13-19 years old)                                0.033         <1.0           40            5          980
--------------------------------------------------------------
Adults (20-49 years old)                               0.033         <1.0           40            5        1,100
--------------------------------------------------------------
Adults (50+ years old)                                 0.033        < 1.0           40            5        1,200
--------------------------------------------------------------
Females (13-49 years old)                              0.033         <1.0           40            5          980
----------------------------------------------------------------------------------------------------------------

    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). Isoxadifen-ethyl is 
proposed for a use that could result in short-term residential 
exposure, and the Agency has determined that it is appropriate to 
aggregate chronic food and water, and short-term exposures for 
isoxadifen-ethyl.
    Using the exposure assumptions described in this unit for short-
term exposures, EPA has concluded that aggregated food and residential 
exposures result in the following aggregate MOEs: U.S. population 
(1,450), all infants <1 year old (780), children 1-2 years old (776), 
children 3-5 years old (774), children 6-12 years old (779), youth 13-
19 years old (1,438), adults 20-49 years old (1,455), adults 50+ years 
old (1,468) and females 13-49 years old (1,456). These aggregate MOEs 
do not exceed the Agency's LOC (<100) for aggregate exposure to food 
and residential uses. In addition, short-term DWLOCs were calculated 
and compared to the chronic EECs of isoxadifen-ethyl in ground water 
and surface water. DWLOCs were calculated and then compared to the EECs 
for surface water and ground water. All DWLOCs are greater than the 
EECs. Therefore, EPA does not expect short-term aggregate exposure to 
exceed the Agency's LOC, as shown in Table 5 below:

[[Page 29888]]



                 Table 5.--Aggregate Risk Assessment for Short-Term Exposure to isoxadifen-ethyl
----------------------------------------------------------------------------------------------------------------
                                                  Aggregate                  Surface       Ground
              Population Subgroup                MOE (Food +   Aggregate    Water EEC    Water EEC    Short-Term
                                                Residential)      LOC         (ppb)        (ppb)     DWLOC (ppb)
----------------------------------------------------------------------------------------------------------------
U.S. population                                         1450          100           40            5        4,500
--------------------------------------------------------------
All Infants (<1 year old)                                780          100           40            5        1,200
--------------------------------------------------------------
Children (1-2 years old)                                 776          100           40            5        1,200
--------------------------------------------------------------
Children (3-5 years old)                                 774          100           40            5        1,200
--------------------------------------------------------------
Children (6-12 years old)                                779          100           40            5        1,200
--------------------------------------------------------------
Youth (13-19 years old)                                1,438          100           40            5        3,900
--------------------------------------------------------------
Adults (20-49 years old)                               1,455          100           40            5        4,500
--------------------------------------------------------------
Adults (50+ years old)                                 1,468          100           40            5        4,500
--------------------------------------------------------------
Females (13-49 years old)                              1,456          100           40            5        3,900
----------------------------------------------------------------------------------------------------------------

    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). Isoxadifen-
ethyl is not used or proposed for use on any sites that would result in 
intermediate-term residential exposure. Therefore an intermediate-term 
risk assessment is not needed.
    5. Aggregate cancer risk for U.S. population. The Agency has 
classified isoxadifen-ethyl as ``not likely to be a carcinogen.'' 
Therefore, isoxadifen-ethyl is not expected to pose a cancer risk.
    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 isoxadifen-ethyl residues.

IV. Other Considerations

A. Analytical Enforcement Methodology

    The Agency has reviewed the analytical method validation data 
submitted by Bayer CropScience and the data submitted with the 
Independent Laboratory Validation (ILV). The ILV reported that the 
method worked well. The Agency believes the method is suitable for 
enforcement.
    Adequate enforcement methodology (example--gas chromotography) is 
available to enforce the tolerance expression. The method may be 
requested from: Chief, Analytical Chemistry Branch, Environmental 
Science Center, 701 Mapes Rd., Ft. Meade, MD 20755-5350; telephone 
number: (410) 305-2905; e-mail address: [email protected].

B. International Residue Limits

    There are no CODEX, Canadian, or Mexican tolerances/maximum residue 
levels for isoxadifen-ethyl residues.

V. Conclusion

    Therefore, tolerances are established for combined residues of 
isoxadifen-ethyl, ethyl 4,5-dihydro-5,5-diphenyl-3-isoxazolecarboxylate 
(CAS 163520-33-0) and its metabolites: 4,5-dihydro-5,5-diphenyl-3-
isoxazolecarboxylic acid and [beta]-hydroxy-[beta]-
benezenepropanenitrile, in or on rice commodities: Rice, grain; rice, 
straw; and rice, hulls at 0.10, 0.25, and 0.50 ppm, respectively.

VI. Objections and Hearing Requests

    Under section 408(g) of FFDCA, as amended by 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 FFDCA by FQPA, EPA 
will continue to use those procedures, with appropriate adjustments, 
until the necessary modifications can be made. The new section 408(g) 
of FFDCA 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) of FFDCA, as was 
provided in the old sections 408 and 409 of FFDCA. 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-2004-0093 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 July 26, 
2004.
    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 20460-0001. You may also deliver your 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

[[Page 29889]]

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 [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-
0001.
    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 20460-0001.
    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 ADDRESSES. Mail your 
copies, identified by docket ID number OPP-2004-0093, 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-
0001. In person or by courier, bring a copy to the location of the 
PIRIB described in ADDRESSES. 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. Statutory and Executive Order Reviews

    This final rule establishes a tolerance under section 408(d) of 
FFDCA 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 section 408(d) of FFDCA, 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 section 408(n)(4) of FFDCA. 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.

[[Page 29890]]

VIII. Congressional Review Act

    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.

0
Therefore, 40 CFR chapter I is amended as follows:

PART 180--[AMENDED]

0
1. The authority citation for part 180 continues to read as follows:

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

0
2. Section 180.570 is amended by revising paragraph (a)(2) to read as 
follows:


Sec.  180.570   Isoxadifen-ethyl; tolerances for residues.

    (a) * * *
    (2) Tolerances are established for the residues of isoxadifen-ethyl 
(3-isoxazolecarboxylic acid, 4,5-dihydro-5,5-diphenyl-, ethyl ester 
(CAS No. 163520-33-0)), and its metabolites 4,5-dihydro-5,5-diphenyl-3-
isoxazolecarboxylic acid and [beta]-hydroxy-[beta]-
benezenepropanenitrile when used as an inert ingredient (safener) in or 
on the following raw agricultural commodities, when applied at an 
annual application rate of 0.17 pounds isoxadifen-ethyl/acre.

------------------------------------------------------------------------
                      Commodity                        Parts per million
------------------------------------------------------------------------
Rice, grain..........................................               0.10
Rice, hulls..........................................               0.50
Rice, straw..........................................               0.25
------------------------------------------------------------------------

* * * * *

    Dated: May 11, 2004.
Lois Rossi,
Director, Registration Division, Office of Pesticide Programs.
[FR Doc. 04-11561 Filed 5-25-04; 8:45 am]
BILLING CODE 6560-50-S