[Federal Register Volume 67, Number 168 (Thursday, August 29, 2002)]
[Rules and Regulations]
[Pages 55331-55339]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 02-22092]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 180

[OPP-2002-0220; FRL-7195-8]


Diflufenzopyr; Pesticide Tolerance

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

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SUMMARY: This regulation establishes tolerances for combined residues 
of diflufenzopyr in or on corn, sweet, forage; corn, sweet, kernel plus 
cob with husks removed; and corn, sweet, stover at 0.05 part per 
million (ppm); corn, pop, grain and corn, pop, stover at 0.05 ppm; 
grass, forage at 22 ppm; and grass, hay at 7.0 ppm. This regulation 
also establishes time-limited tolerances for combined residues of 
diflufenzopyr in or on cattle, goat, hog, horse, and sheep meat at 0.60 
ppm; cattle, goat, hog, horse, and sheep kidney at 4.0 ppm; cattle, 
goat, hog, horse, and sheep meat byproducts, except kidney at 0.50 ppm; 
cattle, goat, hog, horse, and sheep fat at 0.30 ppm; and milk at 3.0 
ppm. The Interregional Research Project Number 4 (IR-4) requested these 
tolerances under the Federal Food, Drug, and Cosmetic Act (FFDCA), as 
amended by the Food Quality Protection Act (FQPA) of 1996.

DATES: This regulation is effective August 29, 2002. Objections and 
requests for hearings, identified by docket ID number OPP-2002-0220, 
must be received on or before October 28, 2002.

ADDRESSES: Written objections and hearing requests may be submitted by 
mail, in person, or by courier. Please follow the detailed instructions 
for each method as provided in Unit VI. of the SUPPLEMENTARY 
INFORMATION. To ensure proper receipt by EPA, your objections and 
hearing requests must identify docket ID number OPP-2002-0220 in the 
subject line on the first page of your response.

FOR FURTHER INFORMATION CONTACT: By mail: Shaja R. Brothers, 
Registration Division (7505C), Office of Pesticide Programs, 
Environmental Protection Agency, 1200 Pennsylvania Ave., NW., 
Washington, DC 20460; telephone number: (703) 308-3194; 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
------------------------------------------------------------------------


[[Page 55332]]

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

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

    1. Electronically. You may obtain electronic copies of this 
document, and certain other related documents that might be available 
electronically, from the EPA Internet Home Page at http://www.epa.gov/. 
To access this document, on the Home Page select ``Laws and 
Regulations,'' ``Regulations and Proposed Rules,'' and then look up the 
entry for this document under the ``Federal Register--Environmental 
Documents.'' You can also go directly to the Federal Register listings 
at http://www.epa.gov/fedrgstr/. A frequently updated electronic 
version of 40 CFR part 180 is available at http://www.access.gpo.gov/nara/cfr/cfrhtml_00/Title_40/40cfr180_00.html, a beta site currently 
under development. To access the OPPTS Harmonized Guidelines referenced 
in this document, go directly to the guidelines at http://www.epa.gov/opptsfrs/home/guidelin.htm.
    2. In person. The Agency has established an official record for 
this action under docket ID number OPP-2002-0220. The official record 
consists of the documents specifically referenced in this action, and 
other information related to this action, including any information 
claimed as Confidential Business Information (CBI). This official 
record includes the documents that are physically located in the 
docket, as well as the documents that are referenced in those 
documents. The public version of the official record does not include 
any information claimed as CBI. The public version of the official 
record, which includes printed, paper versions of any electronic 
comments submitted during an applicable comment period is available for 
inspection in the Public Information and Records Integrity Branch 
(PIRIB), Rm. 119, Crystal Mall 2, 1921 Jefferson Davis Hwy., 
Arlington, VA, from 8:30 a.m. to 4 p.m., Monday through Friday, 
excluding legal holidays. The PIRIB telephone number is (703) 305-5805.

II. Background and Statutory Findings

    In the Federal Register of December 12, 2001 (66 FR 64257) (FRL-
6812-7), and June 12, 2002 (67 FR 40292) (FRL-7181-2), EPA issued 
notices 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 0E6185) by IR-4, 681 U.S. Highway 
1 South, North Brunswick, NJ 08902-3390. These notices 
included a summary of the petition prepared by BASF Corporation, the 
registrant. There were no comments received in response to the notices 
of filing.
    The petition requested that 40 CFR 180.549 be amended by 
establishing tolerances for the combined residues of the herbicide 
diflufenzopyr in or on corn, sweet, forage; corn, sweet, kernel plus 
cob with husks removed; and corn, sweet, stover at 0.05 ppm; corn, pop, 
grain, and corn, pop, stover at 0.05 ppm; grass, forage at 22 ppm; and 
grass, hay at 7.0 ppm. The petition was subsequently revised to request 
that 40 CFR 180.549 be amended by establishing time-limited tolerances 
for residues of the herbicide diflufenzopyr, 2-(1-(3,5- 
difluorophenylamino) carbonyl)hydrazono)ethyl)(-3-pyridinecarboxylic 
acid, its metabolites convertible to 8-methylpyrido[2,3-d]pyridazin-
5(6H)-one, and free and acid-released 8-hydroxymethylpyrido[2,3-d] 
pyridazine-2,5(1H,6H)-dione, expressed as diflufenzopyr, in or on 
cattle, goat, hog, horse, and sheep meat at 0.60 ppm; cattle, goat, 
hog, horse, and sheep kidney at 4.0 ppm; cattle, goat, hog, horse, and 
sheep meat byproducts, except kidney at 0.50 ppm; cattle, goat, hog, 
horse, and sheep fat at 0.30 ppm; and milk at 3.0 ppm.
    Section 408(b)(2)(A)(i) of the FFDCA allows EPA to establish a 
tolerance (the legal limit for a pesticide chemical residue in or on a 
food) only if EPA determines that the tolerance is ``safe.'' Section 
408(b)(2)(A)(ii) defines ``safe'' to mean that ``there is a reasonable 
certainty that no harm will result from aggregate exposure to the 
pesticide chemical residue, including all anticipated dietary exposures 
and all other exposures for which there is reliable information.'' This 
includes exposure through drinking water and in residential settings, 
but does not include occupational exposure. Section 408(b)(2)(C) 
requires EPA to give special consideration to exposure of infants and 
children to the pesticide chemical residue in establishing a tolerance 
and to ``ensure that there is a reasonable certainty that no harm will 
result to infants and children from aggregate exposure to the pesticide 
chemical residue. . . .''
    EPA performs a number of analyses to determine the risks from 
aggregate exposure to pesticide residues. For further discussion of the 
regulatory requirements of section 408 and a complete description of 
the risk assessment process, see the final rule on Bifenthrin Pesticide 
Tolerances November 26, 1997 (62 FR 62961) (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 
these actions. EPA has sufficient data to assess the hazards of and to 
make a determination on aggregate exposure, consistent with section 
408(b)(2), for tolerances for the combined residues of diflufenzopyr on 
corn, sweet, forage; corn, sweet, kernel plus cob with husks removed; 
corn, sweet, stover at 0.05 ppm; corn, pop, grain; and corn, pop, 
stover at 0.05 ppm; grass, forage at 22 ppm; grass, hay at 7.0 ppm; 
cattle, goat, hog, horse, and sheep fat at 0.30 ppm; cattle, goat, hog, 
horse, and sheep kidney at 4.0 ppm; cattle, goat, hog, horse, and sheep 
meat byproducts, except kidney at 0.50 ppm; cattle, goat, hog, horse, 
and sheep meat at 0.60 ppm;, and milk at 3.0 ppm. EPA's assessment of 
exposures and risks associated with establishing tolerances follow.

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 diflufenzopyr is 
discussed in Unit III.A. of the Final Rule on Diflufenzopyr Pesticide 
Tolerance published in the Federal Register of January 28, 1999 (64 FR 
4301) (FRL-6053-8).

B. Toxicological Endpoints

    The dose at which no adverse effects are observed (the NOAEL) from 
the toxicology study identified as appropriate for use in risk 
assessment is used to estimate the toxicological level of concern 
(LOC). However, the lowest dose at which adverse effects of concern

[[Page 55333]]

are identified (the LOAEL) is sometimes used for risk assessment if no 
NOAEL was achieved in the toxicology study selected. An uncertainty 
factor (UF) is applied to reflect uncertainties inherent in the 
extrapolation from laboratory animal data to humans and in the 
variations in sensitivity among members of the human population as well 
as other unknowns. An UF of 100 is routinely used, 10X to account for 
interspecies differences and 10X for intraspecies 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 (MOE cancer = point of 
departure/exposures) is calculated. A summary of the toxicological 
endpoints for diflufenzopyr used for human risk assessment is shown in 
the following Table 1:

    Table 1.--Summary of Toxicological Dose and Endpoints for diflufenzopyr 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  NOAEL = 100 milligrams/   FQPA SF = 1X            Rabbit Developmental
 age)                                   kilogram/day (mg/kg/    aPAD = acute RfD.......  LOAEL = 300 mg/kg/day
                                        day)                    FQPA SF = 1.0 mg/kg/day   based on extra ribs
                                       UF = 100...............                            and other skeletal
                                       Acute RfD = 1.0 mg/kg/                             variations in the
                                        day.                                              rabbit developmental
                                                                                          study. These effects
                                                                                          can occur from a
                                                                                          single dose and
                                                                                          females 13-50 are the
                                                                                          population subgroup of
                                                                                          concern. The
                                                                                          developmental findings
                                                                                          occurred at a level of
                                                                                          severe maternal
                                                                                          toxicity.
----------------------------------------------------------------------------------------------------------------
Acute dietary (general population      None                     None                     An appropriate endpoint
 including infants and children)                                                          attributable to a
                                                                                          single exposure for
                                                                                          this population
                                                                                          subgroup was not
                                                                                          identified in the oral
                                                                                          toxicity studies
                                                                                          including the maternal
                                                                                          effects in rat and
                                                                                          rabbit developmental
                                                                                          studies.
----------------------------------------------------------------------------------------------------------------
Chronic dietary (all populations)      NOAEL = 26 mg/kg/day     FQPA SF = 1X             52-Week feeding study
                                       UF = 100...............  cPAD = chronic RfD.....   in dogs
                                       Chronic RfD = 0.26 mg/   FQPA SF = 0.26 mg/kg/    LOAEL = 299 mg/kg/day
                                        kg/day.                  day.                     based on compensated
                                                                                          hemolytic anemia in
                                                                                          both sexes of dogs
----------------------------------------------------------------------------------------------------------------
Short-term, and intermediate-term      None                     None                     No dermal or systemic
 dermal                                                                                   toxicity was seen at
(Residential)........................                                                     1,000 mg/kg/day in the
                                                                                          21-day dermal toxicity
                                                                                          study in rabbits.
                                                                                          Therefore, these risk
                                                                                          assessments were not
                                                                                          performed.
----------------------------------------------------------------------------------------------------------------
Long-term dermal                       None                     None                     The use pattern does
(Residential)........................                                                     not indicate a concern
                                                                                          for potential
                                                                                          residential dermal
                                                                                          exposure. Therefore,
                                                                                          this risk assessment
                                                                                          was not performed.
----------------------------------------------------------------------------------------------------------------
Short-intermediate, and long-term      None                     None                     The use pattern does
 inhalation                                                                               not indicate a concern
(Residential)........................                                                     for potential
                                                                                          residential inhalation
                                                                                          exposure. Therefore,
                                                                                          this risk assessment
                                                                                          was not performed.
----------------------------------------------------------------------------------------------------------------

[[Page 55334]]

 
Cancer (oral, dermal, inhalation)      None                     None                     In accordance with the
                                                                                          1996 Proposed
                                                                                          Guidelines for
                                                                                          Carcinogenicity Risk
                                                                                          Assessments,
                                                                                          diflufenzopyr was
                                                                                          classified as ``Not
                                                                                          Likely'' to be a human
                                                                                          carcinogen. This
                                                                                          classification is
                                                                                          based on the lack of
                                                                                          evidence of
                                                                                          carcinogenicity in
                                                                                          mice and rats when
                                                                                          tested at doses that
                                                                                          were judged to be
                                                                                          adequate to assess
                                                                                          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 180.549) for the combined residues of 
diflufenzopyr, in or on a variety of raw agricultural commodities. 
Time-limited tolerances are currently being established for cattle, 
goat, hog, horse, and sheep meat, kidney, liver, fat, and milk. Risk 
assessments were conducted by EPA to assess dietary exposures from 
diflufenzopyr in food as follows:
    i. Acute exposure. Acute dietary risk assessments are performed for 
a food-use pesticide if a toxicological study has indicated the 
possibility of an effect of concern occurring as a result of a 1-day or 
single exposure. The Dietary Exposure Evaluation Model 
(DEEMTM) analysis evaluated the individual food consumption 
as reported by respondents in the U.S. Department of Agriculture (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 acute exposure assessments: 
An appropriate endpoint attributable to a single exposure for the 
general U.S. population (including infants and children) population 
subgroup was not identified in the oral toxicity studies including the 
maternal effects in rat and rabbit developmental studies. However, a 
Tier 1 acute dietary exposure assessment was performed for females 13-
50 years old using recommended tolerance level residues (livestock) and 
total residues of concern (plants; parent and metabolites). Default 
DEEMTM concentration factors and 100% crop treated 
information were used for all commodities.
    ii. Chronic exposure. In conducting this chronic dietary risk 
assessment, the DEEMTM analysis evaluated the individual 
food consumption as reported by respondents in the USDA 1989-1992 
nationwide CSFII and accumulated exposure to the chemical for each 
commodity. The following assumptions were made for the chronic exposure 
assessments: The chronic dietary exposure analysis was performed for 
the general U.S. population and all population subgroups using 
recommended tolerance level residues (livestock) and total residues of 
concern (plants; parent and metabolites). Default DEEMTM 
concentration factors and 100% crop treated information were used for 
all commodities.
    iii. Cancer. In accordance with the 1996 Proposed Guidelines for 
Carcinogenicity Risk Assessments, diflufenzopyr was classified as ``not 
likely'' to be a human carcinogen, therefore, a cancer exposure 
assessment was not performed.
    2. Dietary exposure from drinking water. The Agency lacks 
sufficient monitoring exposure data to complete a comprehensive dietary 
exposure analysis and risk assessment for diflufenzopyr 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 diflufenzopyr.
    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 SCI-GROW, which predicts pesticide concentrations in ground 
water. 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 screen for sorting out pesticides for which it is 
highly unlikely that drinking water concentrations would 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 diflufenzopyr, they are further 
discussed in the aggregate risk sections in Unit III.E. Diflufenzopyr 
is not very stable and mobile. Based upon proposed uses, fate 
characteristics, and model predictions, the Agency does not expect 
diflufenzopyr to reach drinking water resources in significant 
quantities.
    Based on the GENEEC and SCI-GROW models, the EECs of diflufenzopyr 
for

[[Page 55335]]

acute exposures are estimated to be 3.80 parts per billion (ppb) for 
surface water and 0.006 ppb for ground water. The EECs for chronic 
exposures are estimated to be 0.65 ppb for surface water and 0.006 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). Diflufenzopyr is not 
registered for use on any sites that would result in residential 
exposure, therefore, a residential exposure assessment was not 
performed.
    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 diflufenzopyr 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, 
diflufenzopyr 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 diflufenzopyr 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 tenfold margin of safety for infants and children in the 
case of threshold effects to account for prenatal and postnatal 
toxicity and the completeness of the data base on toxicity and exposure 
unless EPA determines that a different margin of safety will be safe 
for infants and children. Margins of safety are incorporated into EPA 
risk assessments either directly through use of a margin of exposure 
(MOE) analysis or through using uncertainty (safety) factors in 
calculating a dose level that poses no appreciable risk to humans.
    2. Prenatal and postnatal sensitivity. Developmental NOAEL and the 
lowest observed adverse effect level (LOAEL) for both rats and rabbits 
occurred at either the same dose levels or were above the NOAELs and 
LOAELs for maternal toxicity. The NOAEL for pup effects in the 2-
generation rat reproduction study occurred at dose levels above the 
NOAEL for parental findings. Based on these data, EPA determined that 
there was no evidence of increased sensitivity for infants and 
children.
    3. Conclusion. There is a complete toxicity data base for 
diflufenzopyr and exposure data are complete or are estimated based on 
data that reasonably accounts for potential exposures. EPA determined 
that the 10X safety factor to protect infants and children should be 
reduced to 1X. The FQPA safety factor is reduced because: (1) The 
toxicology data base is complete; (2) there is no indication of 
increased susceptibility of rats and rabbits fetuses to in utero, and/
or postnatal exposure in the developmental and reproductive toxicity 
data; (3) unrefined (tier 1) dietary exposure estimates used in the 
risk assessment are protective since they will exaggerate dietary 
exposure estimates; (4) modeling data are used for ground and surface 
source drinking water exposure assessments resulting in estimates 
considered to be upper-bound concentrations; and (5) there are 
currently no registered residential uses for diflufenzopyr.

E. Aggregate Risks and Determination of Safety

    To estimate total aggregate exposure to a pesticide from food, 
drinking water, and residential uses, the Agency calculates DWLOCs 
which are used as a point of comparison against the model estimates of 
a pesticide's concentration in water (EECs). DWLOC values are not 
regulatory standards for drinking water. DWLOCs are theoretical upper 
limits on a pesticide's concentration in drinking water in light of 
total aggregate exposure to a pesticide in food and residential uses. 
In calculating a DWLOC, the Agency determines how much of the 
acceptable exposure (i.e., the PAD) is available for exposure through 
drinking water (e.g., allowable chronic water exposure (mg/kg/day) = 
cPAD - (average food + residential exposure)). This allowable exposure 
through drinking water is used to calculate a DWLOC.
    A DWLOC will vary depending on the toxic endpoint, drinking water 
consumption, and body weights. Default body weights and consumption 
values as used by the EPA Office of Water are used to calculate DWLOCs: 
2L/70 kg (adult male), 2L/60 kg (adult female), and 1L/10 kg (child). 
Default body weights and drinking water consumption values vary on an 
individual basis. This variation will be taken into account in more 
refined screening-level and quantitative drinking water exposure 
assessments. Different populations will have different DWLOCs. 
Generally, a DWLOC is calculated for each type of risk assessment used: 
Acute, short-term, intermediate-term, chronic, and cancer.
    When EECs for surface water and ground water are less than the 
calculated DWLOCs, EPA concludes with reasonable certainty that 
exposures to the pesticide in drinking water (when considered along 
with other sources of exposure for which EPA has reliable data) would 
not result in unacceptable levels of aggregate human health risk at 
this time. Because EPA considers the aggregate risk resulting from 
multiple exposure pathways associated with a pesticide's uses, levels 
of comparison in drinking water may vary as those uses change. If new 
uses are added in the future, EPA will reassess the potential impacts 
of residues of the pesticide in drinking water as a part of the 
aggregate risk assessment process.
    1. Acute risk. An appropriate endpoint attributable to a single 
exposure for the general U.S. population (including infants and 
children) population subgroup was not identified. Therefore, the data 
do not indicate any adverse effect to the U.S. population subgroup as a 
result of acute dietary exposure. The acute dietary exposure assessment 
was performed for females 13-50 years old using tolerance level 
residues (livestock) and total residues of concern (plants; parent and 
metabolites). Using the exposure assumptions discussed in this unit for 
acute exposure, the acute dietary exposure from food to diflufenzopyr 
will occupy 4% of the aPAD for females 13 years and older. In addition, 
there is potential for acute dietary exposure to diflufenzopyr 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 aPAD, as shown in the following Table 2:

[[Page 55336]]



                     Table 2.--Aggregate Risk Assessment for Acute Exposure to diflufenzopyr
----------------------------------------------------------------------------------------------------------------
                                                                             Surface       Ground
              Population Subgroup                 aPAD (mg/      %aPAD      Water EEC    Water EEC   Acute DWLOC
                                                     kg)         (Food)       (ppb)        (ppb)        (ppb)
----------------------------------------------------------------------------------------------------------------
Females (13-50 years old)                                1.0            4         3.80        0.006       29,000
----------------------------------------------------------------------------------------------------------------

    2. Chronic risk. Using the exposure assumptions described in this 
unit for chronic exposure, EPA has concluded that exposure to 
diflufenzopyr from food will utilize 9% of the cPAD for the U.S. 
population and all population subgroups. The most highly exposed 
population subgroup was children 1-6 years old utilizing 32% of the 
cPAD. There are no residential uses for diflufenzopyr that result in 
chronic residential exposure to diflufenzopyr. In addition, there is 
potential for chronic dietary exposure to diflufenzopyr in drinking 
water. After calculating DWLOCs and comparing them to the EECs for 
surface water and ground water, EPA does not expect the aggregate 
exposure to exceed 100% of the cPAD, as shown in the following Table 3:

             Table 3.--Aggregate Risk Assessment for Chronic (Non-Cancer) Exposure to diflufenzopyr
----------------------------------------------------------------------------------------------------------------
                                                                             Surface       Ground
              Population Subgroup                cPAD mg/kg/     %cPAD      Water EEC    Water EEC     Chronic
                                                     day         (Food)       (ppb)        (ppb)     DWLOC (ppb)
----------------------------------------------------------------------------------------------------------------
U.S. population                                         0.26            9         0.65        0.006        8,300
----------------------------------------------------------------------------------------------------------------
Females (13-50 years old)                               0.26            5         0.65        0.006        7,400
----------------------------------------------------------------------------------------------------------------
Children (1-6 years old)                                0.26           32         0.65        0.006        1,800
----------------------------------------------------------------------------------------------------------------
All infants (less than 1-year)                          0.26           14         0.65        0.006        2,200
----------------------------------------------------------------------------------------------------------------

    3. Short-term and intermediate-term risk. Short-term and 
intermediate-term aggregate exposures take into account residential 
exposure plus chronic exposure to food and water (considered to be a 
background exposure level). Short-term and intermediate-term aggregate 
risk assessments were not performed since there are no registered or 
proposed residential uses for diflufenzopyr. Therefore, short-term and 
intermediate-term exposure is not expected.
    4. Aggregate cancer risk for U.S. population. In accordance with 
the 1996 Proposed Guidelines for Carcinogenicity Risk Assessments, 
diflufenzopyr was classified as ``not likely'' to be a human 
carcinogen. This classification is based on the lack of evidence of 
carcinogenicity in mice and rats when tested at doses that were judged 
to be adequate to assess carcinogenicity. The Agency concludes that 
pesticidal uses of diflufenzopyr are not likely to pose a carcinogenic 
risk to humans.
    5. 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 diflufenzopyr residues.

IV. Other Considerations

A. Analytical Enforcement Methodology

    1. Plants. An adequate enforcement method is available for 
enforcement of the proposed tolerances for sweet corn and pop corn. The 
Agency has conducted a successful petition method validation (PMV) of 
method, and will be forwarded to the Food and Drug Administration (FDA) 
for inclusion in Pesticide Analytical Method Volume (PAM) Vol. II. The 
method may be requested from: Francis Griffith, Analytical Chemistry 
Branch, Environmental Science Center, Environmental Protection Agency, 
701 Mapes Road, Fort George G. Mead, MD 20755-5350; telephone number: 
(410) 305-20905; e-mail address: [email protected].
    2. Livestock. BASF Corporation has submitted an analytical method 
for livestock commodities, which has undergone independent laboratory 
validation.

B. International Residue Limits

    There are currently no established Codex, Mexican maximum residue 
limits (MRLs) for residues of diflufenzopyr in/on plant or livestock 
commodities. A Canadian MRL of 0.05 ppm for residues of diflufenzopyr, 
expressed as the parent and metabolites convertible to M1, has been 
established for corn. No compatibility issues exist with regard to the 
existing and proposed U.S. tolerances.

C. Conditions

    The registrant submitted a meat and milk magnitude of residue study 
in lactating dairy cows. Registration for use of diflufenzopyr on sweet 
corn, pop corn, forage, and hay grasses will be conditional pending the 
outcome of the Agency's review of the submitted study.

V. Conclusion

    Therefore, the tolerances are established for combined residues of 
diflufenzopyr, 2-(1-[([3,5-difluorophenylamino] 
carbonyl)hydrazono]ethyl)-3-pyridinecarboxylic acid, and its 
metabolites convertible to 8-methylpyrido[2,3-d]pyridazin-5(6H)-one, 
expressed as diflufenzopyr, in or on corn, sweet, forage; corn, sweet, 
kernel plus cob with husks removed; and corn, sweet, stover at 0.05 
ppm; corn, pop, grain, and corn, pop, stover at 0.05 ppm; forage, grass 
at 22 ppm; and forage, hay at 7.0 ppm.
    Time-limited tolerances are also established for combined residues 
of diflufenzopyr, 2-(1-[([3,5-difluorophenylamino] 
carbonyl)hydrazono]ethyl)-3-pyridinecarboxylic acid, its metabolites 
convertible to 8-methylpyrido[2,3-d]pyridazin-5(6H)-one, and free and 
acid-released 8-hydroxymethylpyrido[2,3-d]pyridazine-

[[Page 55337]]

2,5(1H,6H)-dione, expressed as diflufenzopyr, in or on cattle, goat, 
hog, horse, and sheep meat at 0.60 ppm; cattle, goat, hog, horse, and 
sheep kidney at 4.0 ppm; cattle, goat, hog, horse, and sheep meat 
byproducts, except kidney at 0.50 ppm; cattle, goat, hog, horse, and 
sheep fat at 0.30 ppm; and milk at 3.0 ppm.

VI. Objections and Hearing Requests

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

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

    You must file your objection or request a hearing on this 
regulation in accordance with the instructions provided in this unit 
and in 40 CFR part 178. To ensure proper receipt by EPA, you must 
identify docket ID number OPP-2002-0220 in the subject line on the 
first page of your submission. All requests must be in writing, and 
must be mailed or delivered to the Hearing Clerk on or before October 
28, 2002.
    1. Filing the request. Your objection must specify the specific 
provisions in the regulation that you object to, and the grounds for 
the objections (40 CFR 178.25). If a hearing is requested, the 
objections must include a statement of the factual issues(s) on which a 
hearing is requested, the requestor's contentions on such issues, and a 
summary of any evidence relied upon by the objector (40 CFR 178.27). 
Information submitted in connection with an objection or hearing 
request may be claimed confidential by marking any part or all of that 
information as CBI. Information so marked will not be disclosed except 
in accordance with procedures set forth in 40 CFR part 2. A copy of the 
information that does not contain CBI must be submitted for inclusion 
in the public record. Information not marked confidential may be 
disclosed publicly by EPA without prior notice.
    Mail your written request to: Office of the Hearing Clerk (1900C), 
Environmental Protection Agency, 1200 Pennsylvania Ave., NW., 
Washington, DC 20460. You may also deliver your written request to the 
Office of the Hearing Clerk in Rm. 104, Crystal Mall  2, 1921 
Jefferson Davis Hwy., Arlington, VA. The Office of the Hearing Clerk is 
open from 8 a.m. to 4 p.m., Monday through Friday, excluding legal 
holidays. The telephone number for the Office of the Hearing Clerk is 
(703) 603-0061.
    2. Tolerance fee payment. If you file an objection or request a 
hearing, you must also pay the fee prescribed by 40 CFR 180.33(i) or 
request a waiver of that fee pursuant to 40 CFR 180.33(m). You must 
mail the fee to: EPA Headquarters Accounting Operations Branch, Office 
of Pesticide Programs, P.O. Box 360277M, Pittsburgh, PA 15251. Please 
identify the fee submission by labeling it ``Tolerance Petition Fees.''
    EPA is authorized to waive any fee requirement ``when in the 
judgement of the Administrator such a waiver or refund is equitable and 
not contrary to the purpose of this subsection.'' For additional 
information regarding the waiver of these fees, you may contact James 
Tompkins by phone at (703) 305-5697, by e-mail at [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 ID number OPP-2002-0220, 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). 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

[[Page 55338]]

technical standards that would require Agency consideration of 
voluntary consensus standards pursuant to section 12(d) of the National 
Technology Transfer and Advancement Act of 1995 (NTTAA), Public Law 
104-113, section 12(d) (15 U.S.C. 272 note). Since tolerances and 
exemptions that are established on the basis of a petition under FFDCA 
section 408(d), such as the tolerance in this final rule, do not 
require the issuance of a proposed rule, the requirements of the 
Regulatory Flexibility Act (RFA) (5 U.S.C. 601 et seq.) do not apply. 
In addition, the Agency has determined that this action will not have a 
substantial direct effect on States, on the relationship between the 
national government and the States, or on the distribution of power and 
responsibilities among the various levels of government, as specified 
in Executive Order 13132, entitled Federalism (64 FR 43255, August 10, 
1999). Executive Order 13132 requires EPA to develop an accountable 
process to ensure ``meaningful and timely input by State and local 
officials in the development of regulatory policies that have 
federalism implications.'' ``Policies that have federalism 
implications'' is defined in the Executive Order to include regulations 
that have ``substantial direct effects on the States, on the 
relationship between the national government and the States, or on the 
distribution of power and responsibilities among the various levels of 
government.'' This final rule directly regulates growers, food 
processors, food handlers and food retailers, not States. This action 
does not alter the relationships or distribution of power and 
responsibilities established by Congress in the preemption provisions 
of FFDCA section 408(n)(4). For these same reasons, the Agency has 
determined that this rule does not have any ``tribal implications'' as 
described in Executive Order 13175, entitled Consultation and 
Coordination with Indian Tribal Governments (65 FR 67249, November 6, 
2000). Executive Order 13175, requires EPA to develop an accountable 
process to ensure ``meaningful and timely input by tribal officials in 
the development of regulatory policies that have tribal implications.'' 
``Policies that have tribal implications'' is defined in the Executive 
Order to include regulations that have ``substantial direct effects on 
one or more Indian tribes, on the relationship between the Federal 
Government and the Indian tribes, or on the distribution of power and 
responsibilities between the Federal Government and Indian tribes.'' 
This rule will not have substantial direct effects on tribal 
governments, on the relationship between the Federal Government and 
Indian tribes, or on the distribution of power and responsibilities 
between the Federal Government and Indian tribes, as specified in 
Executive Order 13175. Thus, Executive Order 13175 does not apply to 
this rule.

VIII. Submission to Congress and the Comptroller General

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

List of Subjects in 40 CFR Part 180

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

    Dated: August 20, 2002.
Debra Edwards,
Acting Director, Registration Division, Office of Pesticide Programs.

    Therefore, 40 CFR chapter I is amended as follows:

PART 180--[AMENDED]

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

    Authority: 21 U.S.C. 321(q), 346(a) and 374.

    2. Section 180.549 is amended by revising paragraph (a) to read as 
follows:


Sec. 180.549  Diflufenzopyr, tolerances for residues.

    (a) General. Tolerances are established for combined residues of 
diflufenzopyr, 2-(1-[([3,5-difluorophenylamino]carbonyl) 
hydrazono]ethyl)-3-pyridinecarboxylic acid, and its metabolites 
convertible to 8-methylpyrido[2,3-d]pyridazin-5(6H)-one, expressed as 
diflufenzopyr, in or on the following raw agricultural commodities:

----------------------------------------------------------------------------------------------------------------
                       Commodity                                            Parts per million
----------------------------------------------------------------------------------------------------------------
Corn, field, forage...................................                                                      0.05
Corn, field, grain....................................                                                      0.05
Corn, field, stover...................................                                                      0.05
Corn, pop, grain......................................                                                      0.05
Corn, pop, stover.....................................                                                      0.05
Corn, sweet, forage...................................                                                      0.05
Corn, sweet, kernel plus cob with husks removed.......                                                      0.05
Corn, sweet, stover...................................                                                      0.05
Grass, forage.........................................                                                      22.0
Grass, hay............................................                                                       7.0
----------------------------------------------------------------------------------------------------------------

    (2) Time-limited tolerances are established for combined residues 
of diflufenzopyr, 2-(1-[([3,5-difluorophenylamino]carbonyl) 
hydrazono]ethyl)-3- pyridinecarboxylic acid, its metabolites 
convertible to 8-methylpyrido[2,3-d]pyridazin- 5(6H)-one, and free and 
acid-released 8-hydroxymethylpyrido[2,3-d]pyridazine-2,5(1H,6H)-dione, 
expressed as diflufenzopyr, in or on the following raw agricultural 
commodities:

----------------------------------------------------------------------------------------------------------------
                Commodity                          Parts per million              Expiration/Revocation Date
----------------------------------------------------------------------------------------------------------------
Cattle, fat.............................                                0.30                             7/31/05
Cattle, kidney..........................                                 4.0                             7/31/05

[[Page 55339]]

 
Cattle, meat............................                                0.60                             7/31/05
Cattle, meat byproducts, except kidney..                                0.50                             7/31/05
Goat, fat...............................                                0.30                             7/31/05
Goat, kidney............................                                 4.0                             7/31/05
Goat, meat..............................                                0.60                             7/31/05
Goat, meat byproducts, except kidney....                                0.50                             7/31/05
Hog, fat................................                                0.30                             7/31/05
Hog, kidney.............................                                 4.0                             7/31/05
Hog, meat...............................                                0.60                             7/31/05
Hog, meat byproducts, except kidney.....                                0.50                             7/31/05
Horse, fat..............................                                0.30                             7/31/05
Horse, kidney...........................                                 4.0                             7/31/05
Horse, meat.............................                                0.60                             7/31/05
Horse, meat byproducts, except kidney...                                0.50                             7/31/05
Milk....................................                                 3.0                             7/31/05
Sheep, fat..............................                                0.30                             7/31/05
Sheep, kidney...........................                                 4.0                             7/31/05
Sheep, meat.............................                                0.60                             7/31/05
Sheep, meat byproducts, except kidney...                                0.50                             7/31/05
----------------------------------------------------------------------------------------------------------------

* * * * *
[FR Doc. 02-22092 Filed 8-28-02; 8:45 a.m.]
BILLING CODE 6560-50-S