[Federal Register Volume 66, Number 247 (Wednesday, December 26, 2001)]
[Rules and Regulations]
[Pages 66325-66333]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 01-31493]


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

ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 180

[OPP-301198; FRL-6816-2]
RIN 2070-AB78


Imazapic; Pesticide Tolerance

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

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

SUMMARY: This regulation establishes a tolerance for combined residues 
of imazapic, ()-2-[4,5-dihydro-4-methyl-4-(1-methylethyl)-
5-oxo-1H-imidazol-2-yl]-5-methyl-3-pyridinecarboxylic acid and its 
metabolite ()-2-[4,5-dihydro-4-methyl-4-(1-methylethyl)-5-
oxo-1H-imidazol-2-yl]-5-hydroxymethyl-3-pyridinecarboxylic acid, both 
free CL 263284 and conjugated CL 189215) in or on grass, forage and 
grass, hay and the combined residues of imazapic and its metabolite CL 
263284 in or on milk; fat, meat, and meat byproducts (except kidney) of 
cattle, goats, horses, and sheep; and kidney of cattle, goats, horses, 
and sheep. BASF requested this tolerance under the Federal Food, Drug, 
and Cosmetic Act, as amended by the Food Quality Protection Act of 
1996.

DATES: This regulation is effective December 26, 2001. Objections and 
requests for hearings, identified by docket control number OPP-301198, 
must be received by EPA on or before February 25, 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 control number OPP-301198 in the 
subject line on the first page of your response.

FOR FURTHER INFORMATION CONTACT: By mail: James A. Tompkins, Product 
Manager (PM) 25, Registration Division (7505C), Office of Pesticide 
Programs, Environmental Protection Agency, 1200 Pennsylvania Ave., 
NW.,Washington, DC 20460; telephone number: (703) 305-5697; and e-mail 
address: [email protected].

SUPPLEMENTARY INFORMATION:

I. General Information

A. Does this Action Apply to Me?

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

 
------------------------------------------------------------------------
                                                          Examples of
           Categories                 NAICS codes         potentially
                                                      affected  entities
------------------------------------------------------------------------
Industry                          111                 Crop production
                                  112                 Animal production
                                  311                 Food manufacturing
                                  32532               Pesticide
                                                       manufacturing
------------------------------------------------------------------------

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

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

    1. Electronically. You may obtain electronic copies of this 
document, and certain other related documents that might be available 
electronically, from the EPA Internet Home Page at http://www.epa.gov/. 
To access this document, on the Home Page select ``Laws and 
Regulations,'' ``Regulations and Proposed Rules,'' and then look up the 
entry for this document under the ``Federal Register--Environmental 
Documents.'' You can also go directly to the Federal Register listings 
at http://www.epa.gov/fedrgstr/. A frequently updated electronic 
version of 40 CFR part 180 is available at http://www.access.gpo.gov/nara/cfr/cfrhtml_00/Title_40/40cfr180_00.html, a beta site currently 
under development. 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 control number OPP-301198. 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 August 24, 2000 (65 FR 51608) (FRL-6598-
6), EPA issued a notice pursuant to section 408 of the Federal Food, 
Drug, and Cosmetic Act (FFDCA), 21 U.S.C. 346a as amended by the Food 
Quality Protection Act of 1996 (FQPA) (Public Law 104-170) announcing 
the filing of a pesticide petition (PP 9F5092) for tolerance by 
American Cyanamid Company, P.O. Box 400, Princeton, NJ 08543-0400. This 
notice included a summary of the petition prepared by American 
Cyanamid, the registrant at the time of filing. The current registrant 
for the chemical is BASF, at the same address. There were no comments 
received in response to the notice of filing.
    The petition requested that 40 CFR 180.490(a) be amended by 
establishing a tolerance for combined residues of the herbicide 
imazapic and its hydroxymethyl metabolite, both free (CL 263284) and 
conjugated (CL 189215) in or on the raw agricultural commodities grass, 
forage at 35 ppm, and grass, hay at 15 parts per million (ppm). 
Tolerances were also proposed for the combined residues of imazapic and 
its free hydroxymethyl metabolite in or on milk at 0.1 ppm; fat, meat, 
and meat byproducts (except kidney) of cattle, goats, horses, and sheep 
at 0.1 ppm; and kidney of cattle, goats, horses, and sheep at 2.0 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

[[Page 66326]]

aggregate exposure to the pesticide chemical residue, including all 
anticipated dietary exposures and all other exposures for which there 
is reliable information.'' This includes exposure through drinking 
water and in residential settings, but does not include occupational 
exposure. Section 408(b)(2)(C) requires EPA to give special 
consideration to exposure of infants and children to the pesticide 
chemical residue in establishing a tolerance and to ``ensure that there 
is a reasonable certainty that no harm will result to infants and 
children from aggregate exposure to the pesticide chemical residue. . . 
.''
    EPA performs a number of analyses to determine the risks from 
aggregate exposure to pesticide residues. For further discussion of the 
regulatory requirements of section 408 and a complete description of 
the risk assessment process, see the final rule on Bifenthrin Pesticide 
Tolerances (62 FR 62961, November 26, 1997) (FRL-5754-7).

III. Aggregate Risk Assessment and Determination of Safety

    Consistent with section 408(b)(2)(D), EPA has reviewed the 
available scientific data and other relevant information in support of 
this action. EPA has sufficient data to assess the hazards of and to 
make a determination on aggregate exposure, consistent with section 
408(b)(2), for a tolerance for combined residues of imazapic and its 
metabolite, both free CL 263284 and conjugated CL 189215, in or on 
grass, forage at 30 ppm, and grass, hay at 15 ppm; and for the combined 
residues of imazapic and its free hydroxymethyl metabolite in milk at 
0.1 ppm; fat, meat, and meat byproducts (except kidney) of cattle, 
goats, horses, and sheep at 0.1 ppm; and kidney of cattle, goats, 
horses, and sheep at 1.0 ppm. EPA's assessment of exposures and risks 
associated with establishing the tolerance follows.

A. Toxicological Profile

    EPA has evaluated the available toxicity data and considered its 
validity, completeness, and reliability as well as the relationship of 
the results of the studies to human risk. EPA has also considered 
available information concerning the variability of the sensitivities 
of major identifiable subgroups of consumers, including infants and 
children. The nature of the toxic effects caused by imazapic are 
discussed in the following Table 1 as well as the no observed adverse 
effect level (NOAEL) and the lowest observed adverse effect level 
(LOAEL) from the toxicity studies reviewed.

  Table 1.--Imazapic Technical Subchronic, Chronic, and Other Toxicity
------------------------------------------------------------------------
                                    Study Type (All
          Guideline No.                 Studies             Results
                                      Acceptable)
------------------------------------------------------------------------
870.3100                          90-Day oral         NOAEL = 1,552 mg/
                                   toxicity rodents-   kg/day in males,
                                   rat                 1,728 mg/kg/day
                                                       in females (HDT)
                                                      LOAEL = not
                                                       established
------------------------------------------------------------------------
870.3200                          21-Day dermal       NOAEL = 1,000 mg/
                                   toxicity-rabbit     kg/day (males and
                                                       females)
                                                      LOAEL = not
                                                       established
------------------------------------------------------------------------
870.3700                          Prenatal            Maternal NOAEL =
                                   developmental in    1,000 mg/kg/day
                                   rodents-rat         (HDT)
                                                      LOAEL = not
                                                       established
                                                      Developmental
                                                       NOAEL = 1,000 mg/
                                                       kg/day
                                                      LOAEL = not
                                                       established
------------------------------------------------------------------------
870.3700                          Prenatal            Maternal NOAEL =
                                   developmental in    350 mg/kg/day
                                   nonrodents-rabbit  LOAEL = 500 mg/kg/
                                                       day based on
                                                       decreased body
                                                       weight gain and
                                                       food consumption.
                                                       At 700 mg/kg/day
                                                       (HDT), there was
                                                       excessive
                                                       mortality
                                                       resulting in a
                                                       total of only 7
                                                       surviving litters
                                                      Developmental
                                                       NOAEL = 500 mg/kg/
                                                       day
                                                      LOAEL = not
                                                       established. Due
                                                       to excessive
                                                       mortality at 700
                                                       mg/kg/day, only
                                                       47 fetuses were
                                                       available for
                                                       examination which
                                                       precluded a
                                                       meaningful
                                                       evaluation of
                                                       developmental
                                                       findings at this
                                                       dose level
------------------------------------------------------------------------
870.3800                          Reproduction and    Parental/Systemic
                                   fertility effects-  NOAEL = 1,205 mg/
                                   rat                 kg/day in males,
                                                       1,484 mg/kg/day
                                                       in females (HDT)
                                                      LOAEL = not
                                                       established
                                                      Reproductive NOAEL
                                                       = 1,205 mg/kg/day
                                                       in males, 1,484
                                                       mg/kg/day in
                                                       females
                                                      LOAEL = not
                                                       established
                                                      Offspring NOAEL =
                                                       1,205 mg/kg/day
                                                       in males, 1,484
                                                       mg/kg/day in
                                                       females
                                                      LOAEL = not
                                                       established
------------------------------------------------------------------------

[[Page 66327]]

 
870.4100                          Chronic toxicity    NOAEL = not
                                   dogs                established
                                                      LOAEL = 137 mg/kg/
                                                       day in males, 180
                                                       mg/kg/day in
                                                       females based on
                                                       increased
                                                       incidence of
                                                       minimal
                                                       degeneration and/
                                                       or necrosis and
                                                       lymphocyte and/or
                                                       macrophage
                                                       infiltration in
                                                       skeletal muscle
                                                       in both males and
                                                       females and
                                                       slightly
                                                       decreased blood
                                                       creatinine levels
                                                       in females (LDT)
------------------------------------------------------------------------
870.4100/870.4200                 Chronic/            NOAEL = 1,029 mg/
                                   carcinogenicity     kg/day in males,
                                   rats                1,237 mg/kg/day
                                                       in females (HDT)
                                                      LOAEL = not
                                                       established
                                                      No evidence of
                                                       carcinogenicity
------------------------------------------------------------------------
870.4300                          Carcinogenicity     NOAEL = 1,134 mg/
                                   mice                kg/day in males,
                                                       1,422 mg/kg/day
                                                       in females (HDT)
                                                      LOAEL = not
                                                       established
                                                      No evidence of
                                                       carcinogenicity
------------------------------------------------------------------------
870.5265                          Gene mutation       Non-mutagenic when
                                                       tested up to
                                                       5,000 g/
                                                       plate, in
                                                       presence and
                                                       absence of
                                                       activation, in S.
                                                       typhimurium
                                                       strains TA98,
                                                       TA100, TA1535 and
                                                       TA1537 and E.coli
                                                       strain WP2uvra.
------------------------------------------------------------------------
870.5300                          Gene mutation       Non-mutagenic at
                                                       the HGPRT locus
                                                       in Chinese
                                                       hamster ovary
                                                       (CHO) cells
                                                       tested up to
                                                       cytotoxic
                                                       concentrations or
                                                       limit of
                                                       solubility, in
                                                       presence and
                                                       absence of
                                                       activation.
------------------------------------------------------------------------
870.5375                          Chromosome          Did not induce
                                   aberration          structural
                                                       chromosome
                                                       aberration in CHO
                                                       cell cultures in
                                                       the presence and
                                                       absence of
                                                       activation.
------------------------------------------------------------------------
870.5385                          Chromosomal         Non-mutagenic in
                                   aberration          rat bone marrow
                                                       chromosomal
                                                       aberrations assay
                                                       up to 5,000 mg/
                                                       kg.
------------------------------------------------------------------------
870.7485                          Metabolism and      Total recovery of
                                   pharmacokinetics -  the administered
                                    rat                dose was 98-106%
                                                       at 7 days.
                                                       Urinary excretion
                                                       was the major
                                                       route of
                                                       elimination (94-
                                                       102% of the
                                                       dose), with only
                                                       unchanged parent
                                                       detected. There
                                                       was no evidence
                                                       of
                                                       bioaccumulation
                                                       in the tissues.
                                                       There were no sex-
                                                        or dose-related
                                                       differences
                                                       following oral or
                                                       intravenous
                                                       administration.
------------------------------------------------------------------------

B. Toxicological Endpoints

    The dose at which no adverse effects are observed (the NOAEL) from 
the toxicology study identified as appropriate for use in risk 
assessment is used to estimate the toxicological level of concern 
(LOC). However, the lowest dose at which adverse effects of concern are 
identified (the LOAEL) is sometimes used for risk assessment if no 
NOAEL was achieved in the toxicology study selected. An uncertainty 
factor (UF) is applied to reflect uncertainties inherent in the 
extrapolation from laboratory animal data to humans and in the 
variations in sensitivity among members of the human population as well 
as other unknowns. An UF of 100 is routinely used, 10X to account for 
interspecies differences and 10X for intraspecies differences. Because 
a developmental neurotoxicity study is not needed, there are currently 
no residential uses, dietary exposure assessments will not 
underestimate the potential exposures for infants and children, and the 
toxicology database is complete, no additional FQPA Safety Factor (FQPA 
SF) is required.
    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.

[[Page 66328]]

A Q* is calculated and used to estimate risk which represents a 
probability of occurrence of additional cancer cases (e.g., risk is 
expressed as 1 x 10 -6 or one in a million). Under certain 
specific circumstances, MOE calculations will be used for the 
carcinogenic risk assessment. In this non-linear approach, a ``point of 
departure'' is identified below which carcinogenic effects are not 
expected. The point of departure is typically a NOAEL based on an 
endpoint related to cancer effects though it may be a different value 
derived from the dose response curve. To estimate risk, a ratio of the 
point of departure to exposure (MOEcancer = point of 
departure/exposures) is calculated. A summary of the toxicological 
endpoints for imazapic used for human risk assessment is shown in the 
following Table 2:

       Table 2.--Summary of Toxicological Dose and Endpoints for Imazapic 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 (general population and  None                     An acute dietary         None
 females 13-50 years old)                                        endpoint was not
                                                                 selected based on the
                                                                 absence of an
                                                                 appropriate endpoint
                                                                 attributed to a single
                                                                 dose
----------------------------------------------------------------------------------------------------------------
Chronic dietary (all populations)      LOAEL= 137 mg/kg/day     FQPA SF = 1X             LOAEL = 137 mg/kg/day
                                       UF = 300...............  cPAD = cRfD/FQPA.......   based on increased
                                       Chronic RfD = 0.5 mg/kg/ SF = 0.5 mg/kg/day.....   incidence of minimal
                                        day.                                              degeneration and/or
                                                                                          necrosis of skeletal
                                                                                          muscle in 1 year dog
                                                                                          feeding study
----------------------------------------------------------------------------------------------------------------
Incidental oral, short-term (1-7       Oral NOAEL = 350 mg/kg/  LOC = 100                LOAEL = 500 mg/kg/day
 days)                                  day                                               based on decreased
                                                                                          body weight and food
                                                                                          consumption during the
                                                                                          dosing period in
                                                                                          rabbit developmental
                                                                                          study
----------------------------------------------------------------------------------------------------------------
Incidental oral, intermediate-term (7  Oral NOAEL = 350 mg/kg/  LOC = 100                LOAEL = 500 mg/kg/day
 days-several months)                   day                                               based on decreased
                                                                                          body weight and food
                                                                                          consumption during the
                                                                                          dosing period in
                                                                                          rabbit developmental
                                                                                          study
----------------------------------------------------------------------------------------------------------------
Short- and intermediate-term dermal    None                     No systemic toxicity     None
 (1-7 days and 1 week-several months)                            was seen following
(Occupational).......................                            repeated dermal
                                                                 application at 1,000
                                                                 mg/kg/day over a 3-
                                                                 week period. Since no
                                                                 hazard was identified,
                                                                 quantification is not
                                                                 required.
----------------------------------------------------------------------------------------------------------------
Long-term dermal (several months-      Oral LOAEL = 137 mg/kg/  LOC for MOE = 300        LOAEL = 137 mg/kg/day
 lifetime)                              day (dermal absorption                            based on increased
(Occupational).......................   rate = 50%)                                       incidence of minimal
                                                                                          degeneration and/or
                                                                                          necrosis of skeletal
                                                                                          muscle in 1 year dog
                                                                                          feeding study
----------------------------------------------------------------------------------------------------------------
Short- and intermediate-term           Oral study NOAEL= 350    LOC for MOE = 100        LOAEL = 500 mg/kg/day
 inhalation (1-7 days and 1 week-       mg/kg/day (inhalation                             based on decreased
 several months)                        absorption rate =                                 body weight and food
(Occupational).......................   100%)                                             consumption during
                                                                                          dosing in rabbit
                                                                                          developmental study
----------------------------------------------------------------------------------------------------------------
Long-term inhalation (several months-  Oral study LOAEL= 137    LOC for MOE = 300        LOAEL = 137 mg/kg/day
 lifetime)                              mg/kg/day (inhalation                             based on increased
(Occupational).......................   absorption rate =                                 incidence of minimal
                                        100%)                                             degeneration and/or
                                                                                          necrosis of skeletal
                                                                                          muscle in 1 year dog
                                                                                          feeding study
----------------------------------------------------------------------------------------------------------------
Cancer (oral, dermal, inhalation)      Cancer classification    Risk assessment not      No evidence of
                                        (``Group E'')            required                 carcinogenicity
----------------------------------------------------------------------------------------------------------------

C. Exposure Assessment

    1. Dietary exposure from food and feed uses. Tolerances have been 
established (40 CFR 180.490(a) for the combined residues of imazapic 
and its metabolites CL 263284 and CL 189215, in or on peanut, nutmeat 
at 0.1 ppm. Time-limited tolerances set to expire December 31, 2001 are 
established under (40 CFR 180.490(b) in connection with section 18 
emergency exemptions (99NE0009) for residues of imazapic and its 
metabolites CL 263284 and CL 189215 for grass, forage at 30 ppm; grass, 
hay at 15 ppm; milk at 0.10 ppm; fat, meat, and meat byproducts (except 
kidney) of cattle, goats, hogs, horses, and sheep at 0.10 ppm; and 
kidney of cattle, goats, hogs, horses, and sheep at 1.0 ppm. The 
present analyses included the published peanut values together with re-
evaluated tolerance levels for livestock-derived commodities, based on 
the new grass use proposed. Risk assessments were conducted by EPA to 
assess dietary exposures from imazapic in food as follows:
    i. Acute exposure. Acute dietary risk assessments are performed for 
a food-

[[Page 66329]]

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. An acute exposure assessment is not applicable based on the 
absence of an appropriate effect of concern.
    ii. Chronic exposure. In conducting this chronic dietary risk 
assessment the Dietary Exposure Evaluation Model (DEEMTM 
version 7.73) analysis evaluated the individual food consumption as 
reported by respondents in the USDA 1989-1992 nationwide Continuing 
Surveys of Food Intake by Individuals (CSFII) and accumulated exposure 
to the chemical for each commodity. The following assumptions were made 
for the chronic exposure assessments: Residues present at tolerance 
levels, 100% of each crop is treated, and the use of default processing 
concentration factors (Tier 1 analysis).
    iii. Cancer. A cancer risk assessment was not conducted, since 
imazapic has been classified as a ``Group E'' chemical (evidence of 
non-carcinogenicity for humans) based upon lack of evidence of 
carcinogenicity in two adequate studies (rats and mice).
    2. Dietary exposure from drinking water. The Agency lacks 
sufficient monitoring exposure data to complete a comprehensive dietary 
exposure analysis and risk assessment for imazapic 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 imazapic.
    The Agency uses the First Index Reservoir Screening Tool (FIRST) or 
the Pesticide Root Zone/Exposure Analysis Modeling System (PRZM/EXAMS), 
to produce estimates of pesticide concentrations in an index reservoir. 
The Screening Concentrations in Ground Water (SCI-GROW) model is used 
to predict pesticide concentrations in shallow ground water. For a 
screening-level assessment for surface water EPA will use FIRST (a tier 
1 model) before using PRZM/EXAMS (a tier 2 model). The FIRST model is a 
subset of the PRZM/EXAMS model that uses a specific high-end runoff 
scenario for pesticides. While both FIRST and PRZM/EXAMS incorporate an 
index reservoir environment, the PRZM/EXAMS model includes a percent 
crop area factor as an adjustment to account for the maximum percent 
crop coverage within a watershed or drainage basin.
    None of these models include consideration of the impact processing 
(mixing, dilution, or treatment) of raw water for distribution as 
drinking water would likely have on the removal of pesticides from the 
source water. The primary use of these models by the Agency at this 
stage is to provide a coarse screen for sorting out pesticides for 
which it is highly unlikely that drinking water concentrations would 
ever exceed human health levels of concern.
    Since the models used are considered to be screening tools in the 
risk assessment process, the Agency does not use estimated 
environmental concentrations (EECs) from these models to quantify 
drinking water exposure and risk as a %RfD or %PAD. Instead drinking 
water levels of comparison (DWLOCs) are calculated and used as a point 
of comparison against the model estimates of a pesticide's 
concentration in water. DWLOCs are theoretical upper limits on a 
pesticide's concentration in drinking water in light of total aggregate 
exposure to a pesticide in food, and from residential uses. Since 
DWLOCs address total aggregate exposure to imazapic they are further 
discussed in the aggregate risk sections below.
    Based on the FIRST and SCI-GROW models, the EECs of imazapic for 
acute exposures are estimated to be 17 parts per billion (ppb) for 
surface water and 14 ppb for ground water. The EECs for chronic 
exposures are estimated to be 1.5 ppb for surface water and 14 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).
    Imazapic is not registered for use on any sites that would result 
in residential exposure.
    4. Cumulative exposure to substances with a common mechanism of 
toxicity. Section 408(b)(2)(D)(v) requires that, when considering 
whether to establish, modify, or revoke a tolerance, the Agency 
consider ``available information'' concerning the cumulative effects of 
a particular pesticide's residues and ``other substances that have a 
common mechanism of toxicity.''
    EPA does not have, at this time, available data to determine 
whether imazapic 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, 
imazapic 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 imazapic 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. Based on the available data, 
no evidence of increased susceptibility was seen in the rat and rabbit 
prenatal toxicity studies or following prenatal/postnatal exposure in 
the 2-generation reproduction study.
    3. Conclusion. There is a complete toxicity data base for imazapic 
and exposure data are complete or are estimated based on data that 
reasonably account for potential exposures. EPA determined that the 10X 
safety factor to protect infants and children should be removed. The 
FQPA factor is removed because: A developmental neurotoxicity study is 
not needed; there are currently no residential uses; and dietary 
exposure assessments will not underestimate the potential exposures for 
infants and children.

E. Aggregate Risks and Determination of Safety

    To estimate total aggregate exposure to a pesticide from food, 
drinking water, and residential uses, the Agency calculates DWLOCs 
which are used as a point of comparison against the model estimates of 
a pesticide's concentration in water EECs. DWLOC values are not 
regulatory standards for drinking water. DWLOCs are theoretical upper 
limits on a pesticide's concentration in drinking water in light of 
total aggregate exposure to a pesticide in food and residential uses. 
In calculating a DWLOC, the

[[Page 66330]]

Agency determines how much of the acceptable exposure (i.e., the PAD) 
is available for exposure through drinking water e.g., allowable 
chronic water exposure (mg/kg/day) = cPAD - (average food + residential 
exposure). This allowable exposure through drinking water is used to 
calculate a DWLOC.
    A DWLOC will vary depending on the toxic endpoint, drinking water 
consumption, and body weights. Default body weights and consumption 
values as used by the USEPA Office of Water are used to calculate 
DWLOCs: 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, OPP concludes with reasonable certainty that 
exposures to the pesticide in drinking water (when considered along 
with other sources of exposure for which OPP has reliable data) would 
not result in unacceptable levels of aggregate human health risk at 
this time. Because OPP considers the aggregate risk resulting from 
multiple exposure pathways associated with a pesticide's uses, levels 
of comparison in drinking water may vary as those uses change. If new 
uses are added in the future, OPP will reassess the potential impacts 
of residues of the pesticide in drinking water as a part of the 
aggregate risk assessment process.
    1. Acute risk. Imazapic is not expected to pose an acute risk 
because no acute endpoint of concern was identified in the toxicity 
test.
    2. Chronic risk. Using the exposure assumptions described in this 
unit for chronic exposure, EPA has concluded that exposure to imazapic 
from food will utilize 0.1% of the cPADs for the U.S. population, all 
infants, and children 1-6 years old. There are no residential uses for 
imazapic that result in chronic residential exposure to imazapic. In 
addition, there is potential for chronic dietary exposure to imazapic 
in drinking water. After calculating DWLOCs and comparing them to the 
EECs for surface and ground water, EPA does not expect the aggregate 
exposure to exceed 100% of the cPAD, as shown in the following Table 3:

           Table 3.--Aggregate Risk Assessment for Chronic (Non-Cancer) Exposure to Imazapic Residues
----------------------------------------------------------------------------------------------------------------
                                                                             Surface       Ground
              Population Subgroup                cPAD mg/kg/     %cPAD      Water EEC    Water EEC     Chronic
                                                     day         (Food)       (ppb)        (ppb)     DWLOC (ppb)
----------------------------------------------------------------------------------------------------------------
U.S. population                                          0.5     0.000269          1.5           14       17,000
----------------------------------------------------------------------------------------------------------------
All infants (< 1 year old)                               0.5     0.000505          1.5           14        5,000
----------------------------------------------------------------------------------------------------------------
Children (1-6 years old)                                 0.5     0.000684          1.5           14        5,000
----------------------------------------------------------------------------------------------------------------

    3. Short- or intermediate-term risk. Since there are no registered 
uses for imazapic which would result in non-dietary, non-occupational 
exposure, contributions to the aggregate risk from both short- and 
intermediate-term non-dietary exposures are not expected.
    4. Aggregate cancer risk for U.S. population. Imazapic has been 
classified as a ``Group E'' chemical (evidence of non-carcinogenicity 
for humans); therefore imazapic is not expected to pose a cancer risk.
    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 imazapic residues.

IV. Other Considerations

A. Analytical Enforcement Methodology

    Adequate independent method validation (ILV) studies have been 
submitted in support of all methods. A method which is similar to the 
peanut enforcement method has been submitted for the determination of 
residues of imazapic and its metabolites CL 263284 and CL 189215 in/on 
grass forage and hay, and methods for the enforcement of tolerances of 
imazapic and CL 263284 in milk and livestock tissues and an HPLC/MS 
method for the enforcement of tolerances in fat have been submitted.

B. International Residue Limits

    There are no CODEX, Canadian, or Mexican maximum residue limits 
(MRLs) for imazapic residues.

C. Conditions

    The registrant has committed to conduct four side-by-side grass 
field trials using the maximum rate WDG acid formulation. The 
registrant has also agreed to conduct four additional grass field 
trials reflecting a single postemergence application of the 2 lb acid 
equivalence (ae)/gal ammonium salt SC formulation at 0.1875 lb ae/A; 
these trials will be conducted in Regions 7 and 8. The registrant also 
is required to conduct a 28-day inhalation toxicity study, using the 
protocol for the existing 90-day inhalation toxicity study. The results 
of this study will provide a basis from which to determine more 
reliable route-specific Margins of Exposure (MOEs) for worker 
inhalation risks rather than the less reliable route-to-route MOE 
calculations currently being used.

V. Conclusion

    Therefore, the tolerance is established for combined residues of 
the herbicide imazapic and its hydroxymethyl metabolite, both free (CL 
263284) and conjugated (CL 189215) in or on the raw agricultural 
commodities grass, forage at 30 ppm, and grass, hay at 15 ppm. 
Tolerances are also established for the combined residues of imazapic 
and its free hydroxymethyl metabolite in or on milk at 0.1 ppm; fat, 
meat, and meat byproducts (except kidney) of cattle, goats, horses, and 
sheep at 0.1 ppm; and kidney of cattle, goats, horses, and sheep at 1.0 
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

[[Page 66331]]

necessary modifications can be made. The new section 408(g) provides 
essentially the same process for persons to ``object'' to a regulation 
for an exemption from the requirement of a tolerance issued by EPA 
under new section 408(d), as was provided in the old FFDCA sections 408 
and 409. However, the period for filing objections is now 60 days, 
rather than 30 days.

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

    You must file your objection or request a hearing on this 
regulation in accordance with the instructions provided in this unit 
and in 40 CFR part 178. To ensure proper receipt by EPA, you must 
identify docket control number OPP-301198 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 February 
25, 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 (1900), 
Environmental Protection Agency, 1200 Pennsylvania Ave., NW., 
Washington, DC 20460. You may also deliver your request to the Office 
of the Hearing Clerk in Rm. C400, Waterside Mall, 401 M St., SW., 
Washington, DC 20460. The Office of the Hearing Clerk is open from 8 
a.m. to 4 p.m., Monday through Friday, excluding legal holidays. The 
telephone number for the Office of the Hearing Clerk is (202) 260-4865.
    2. Tolerance fee payment. If you file an objection or request a 
hearing, you must also pay the fee prescribed by 40 CFR 180.33(i) or 
request a waiver of that fee pursuant to 40 CFR 180.33(m). You must 
mail the fee to: EPA Headquarters Accounting Operations Branch, Office 
of Pesticide Programs, P.O. Box 360277M, Pittsburgh, PA 15251. Please 
identify the fee submission by labeling it ``Tolerance Petition Fees.''
    EPA is authorized to waive any fee requirement ``when in the 
judgement of the Administrator such a waiver or refund is equitable and 
not contrary to the purpose of this subsection.'' For additional 
information regarding the waiver of these fees, you may contact James 
Tompkins by phone at (703) 305-5697, by e-mail at [email protected], 
or by mailing a request for information to Mr. Tompkins at Registration 
Division (7505C), Office of Pesticide Programs, Environmental 
Protection Agency, 1200 Pennsylvania Ave., NW., Washington, DC 20460.
    If you would like to request a waiver of the tolerance objection 
fees, you must mail your request for such a waiver to: James Hollins, 
Information Resources and Services Division (7502C), Office of 
Pesticide Programs, Environmental Protection Agency, 1200 Pennsylvania 
Ave., NW., Washington, DC 20460.
    3. Copies for the Docket. In addition to filing an objection or 
hearing request with the Hearing Clerk as described in Unit VI.A., you 
should also send a copy of your request to the PIRIB for its inclusion 
in the official record that is described in Unit I.B.2. Mail your 
copies, identified by docket control number OPP-301198, 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 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

[[Page 66332]]

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: December 11, 2001.
Peter Caulkins,
Acting Director, Registration Division, Office of Pesticide Programs.

    Therefore, 40 CFR chapter I is amended as follows:

PART 180--[AMENDED]

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

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

    2. Section 180.490 is amended by revising paragraph (a) and 
removing and reserving the text of paragraph (b) to read as follows:


Sec. 180.490  Imazapic-ammonium; tolerances for residues.

    (a) General. (1) Tolerances are established for combined residues 
of the herbicide imazapic, ()-2-[4,5-dihydro-4-methyl-4-(1-
methylethyl)-5-oxo-1H-imidazol-2-yl]-5-methyl-3-pyridinecarboxylic acid 
and its metabolite ()-2-[4,5-dihydro-4-methyl-4-(1-
methylethyl)-5-oxo-1H-imidazol-2-yl]-5-hydroxymethyl-3-
pyridinecarboxylic acid, both free and conjugated, in or on the 
following food commodities:

 
----------------------------------------------------------------------------------------------------------------
                            Commodity                                            Parts per million
----------------------------------------------------------------------------------------------------------------
Grass, forage....................................................                                             15
Grass, hay.......................................................                                             30
Peanut nutmeat...................................................                                            0.1
----------------------------------------------------------------------------------------------------------------

    (2) Tolerances are also established for the combined residues of 
the herbicide imazapic, ()-2-[4,5-dihydro-4-methyl-4-(1-
methylethyl)-5-oxo-1H-imidazol-2-yl]-5-methyl-3-pyridinecarboxylic acid 
and its free metabolite ()-2-[4,5-dihydro-4-methyl-4-(1-
methylethyl)-5-oxo-1H-imidazol-2-yl]-5-hydroxymethyl-3-
pyridinecarboxylic acid, in or on the following food commodities:

 
----------------------------------------------------------------------------------------------------------------
                            Commodity                                            Parts per million
----------------------------------------------------------------------------------------------------------------
Cattle, fat......................................................                                           0.10
Cattle, kidney...................................................                                            1.0
Cattle, mbyp (except kidney).....................................                                            0.1
Cattle, meat.....................................................                                            0.1
Goats, fat.......................................................                                            0.1
Goats, kidney....................................................                                            1.0
Goats, mbyp (except kidney)......................................                                            0.1
Goats, meat......................................................                                            0.1
Horses, fat......................................................                                            0.1
Horses, kidney...................................................                                            1.0
Horses, mbyp (except kidney).....................................                                            0.1
Horses, meat.....................................................                                            0.1
Milk.............................................................                                            0.1

[[Page 66333]]

 
Sheep, fat.......................................................                                            0.1
Sheep, kidney....................................................                                            1.0
Sheep, mbyp (except kidney)......................................                                            0.1
Sheep, meat......................................................                                            0.1
----------------------------------------------------------------------------------------------------------------

    (b) Section 18 emergency exemptions. [Reserved]
* * * * *

[FR Doc. 01-31493 Filed 12-21-01; 8:45 am]
BILLING CODE 6560-50-S