Document ID: EPA-HQ-OPP-2006-0072-0004
Agency: epa
Document Type: Rule
Title: Tembotrione; Pesticide Tolerance
Posted Date: 2007-09-28T04:00Z

[Federal Register: September 28, 2007 (Volume 72, Number 188)]
[Rules and Regulations]               
[Page 55078-55085]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr28se07-15]                         

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 180

[EPA-HQ-OPP-2006-0072; FRL-8148-2]

 
Tembotrione; Pesticide Tolerance

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

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SUMMARY: This regulation establishes tolerances for combined residues 
of tembotrione, 2-[2-chloro-4-(methylsulfonyl)-3-[(2,2,2-
trifluoroethoxy)methyl]benzoyl]-1,3-cyclohexanedione and its metabolite 
(M5); 2-[2-chloro-4-(methylsulfonyl)-3-[(2,2,2-
trifluoroethoxy)methyl]benzoyl]-4,6-dihydroxy-1,3-cyclohexanedione in 
or on corn (field, sweet and pop) and livestock commodities. Bayer 
CropScience requested those tolerances under the Federal Food, Drug, 
and Cosmetic Act (FFDCA).

DATES: This regulation is effective September 28, 2007. Objections and 
requests for hearings must be received on or before November 27, 2007, 
and must be filed in accordance with the instructions provided in 40 
CFR part 178 (see also Unit I.C. of the SUPPLEMENTARY INFORMATION ).

ADDRESSES: EPA has established a docket for this action under docket 
identification (ID) number EPA-HQ-OPP-2006-0072. To access the 
electronic docket, go to http://www.regulations.gov, select ``Advanced 

Search,'' then ``Docket Search.'' Insert the docket ID number where 
indicated and select the ``Submit'' button. Follow the instructions on 
the regulations.gov website to view the docket index or access 
available documents. All documents in the docket are listed in the 
docket index available in regulations.gov. Although listed in the 
index, some information is not publicly available, e.g., Confidential 
Business Information (CBI) or other information whose disclosure is 
restricted by statute. Certain other material, such as copyrighted 
material, is not placed on the Internet and will be publicly available 
only in hard copy form. Publicly available docket materials are 
available in the electronic docket at http://www.regulations.gov, or, 

if only available in hard copy, at the OPP Regulatory Public Docket in 
Rm. S-4400, One Potomac Yard (South Bldg.), 2777 S. Crystal Dr., 
Arlington, VA. The Docket Facility is open from 8:30 a.m. to 4 p.m., 
Monday through Friday, excluding legal holidays. The Docket Facility 
telephone number is (703) 305-5805.

FOR FURTHER INFORMATION CONTACT: Eugene Wilson, Registration Division, 
Office of Pesticide Programs, Environmental Protection Agency, 1200 
Pennsylvania Ave., NW., Washington, DC 20460-0001; telephone number: 
(703) 305-6103; e-mail address: wilson.eugene@epa.gov.

SUPPLEMENTARY INFORMATION:

I. General Information

A. Does this Action Apply to Me?

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

B. How Can I Access Electronic Copies of this Document?

    In addition to accessing an electronic copy of this Federal 
Register document through the electronic docket at http://www.regulations.gov
, you may access this Federal Register document 

electronically through the EPA Internet under the ``Federal Register'' 
listings at http://www.epa.gov/fedrgstr. You may also access a 

frequently updated electronic version of EPA's tolerance regulations at 
40 CFR part 180 through the Government Printing Office's pilot e-CFR 
site at http://www.gpoaccess.gov/ecfr.

C. Can I File an Objection or Hearing Request?

    Under section 408(g) of FFDCA, any person may file an objection to 
any aspect of this regulation and may also request a hearing on those 
objections. You must file your objection or request a hearing on this 
regulation in accordance with the instructions provided in 40 CFR part 
178. To ensure proper receipt by EPA, you must identify docket ID 
number EPA-HQ-OPP-2006-0072 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 as required by 40 CFR part 178 on or 
before November 27, 2007.
    In addition to filing an objection or hearing request with the 
Hearing Clerk as described in 40 CFR part 178, please submit a copy of 
the filing that does not contain any CBI for inclusion in the public 
docket that is described in ADDRESSES. Information not marked 
confidential pursuant to 40 CFR part 2 may be disclosed publicly by EPA 
without prior notice. Submit this copy, identified by docket ID number 
EPA-HQ-OPP-2006-0072, by one of the following methods:
     Federal eRulemaking Portal: http://www.regulations.gov. 

Follow the on-line instructions for submitting comments.
     Mail: Office of Pesticide Programs (OPP) Regulatory Public 
Docket (7502P), Environmental Protection Agency, 1200 Pennsylvania 
Ave., NW., Washington, DC 20460-0001.
     Delivery: OPP Regulatory Public Docket (7502P), 
Environmental Protection Agency, Rm. S-4400, One Potomac Yard (South 
Bldg.), 2777 S. Crystal Dr., Arlington, VA. Deliveries are only 
accepted during the Docket's normal hours of operation (8:30 a.m. to 4 
p.m., Monday through Friday, excluding legal holidays). Special 
arrangements should be made for deliveries of boxed information. The 
Docket Facility telephone number is (703) 305-5805.

[[Page 55079]]

II. Petition for Tolerance

    In the Federal Register of April 26, 2006 (71 FR 24690 - 24692) 
(FRL-8063-6), EPA issued a notice pursuant to section 408(d)(3) of the 
FFDCA, 21 U.S.C. 346a(d)(3), announcing the filing of a pesticide 
petition (PP 5F7009) by Bayer CropScience, 2 TW Alexander Drive, P.O. 
Box 12014, RTP, NC 27709. The petition requested that 40 CFR part 180 
be amended by establishing a tolerance for combined residues of the 
herbicide AE 0172747 (tembotrione), 2-[2-chloro-4-(methylsulfonyl)-3-
[(2,2,2-trifluoroethoxy)methyl]benzoyl]-1,3-cyclohexanedione, and 
metabolite (M5), AE 1417268 (2-[2-chloro-4-(methylsulfonyl)-3-[(2,2,2-
trifluoroethoxy)methyl]benzoyl]-4,6-dihydroxy-1,3-cyclohexanedione 
(expressed as tembotrione equivalents in or on corn, field, grain at 
0.02 ppm; corn, field, forage at 0.5 ppm; corn, field, stover at 0.5 
ppm; corn, sweet, kernel plus cob with husks removed at 0.03 ppm; corn, 
sweet, forage at 1.0 ppm; corn sweet, stover at 1.0 ppm; popcorn, grain 
at 0.01 ppm; Popcorn, stover, 0.25 ppm; cattle, liver at 0.5 ppm; 
cattle, meat byproducts, except liver at 0.07 ppm; goat, liver at 0.5 
ppm; goat, kidney at 0.07 ppm; Hog Liver at 0.5; Hog, Kidney at 0.07 
ppm, sheep, kidney at 0.07 ppm; sheep, meat byproducts at 0.5 ppm ; 
horse, kidney at 0.07 ppm; horse, meat byproducts at 0.5 ppm. There 
were no comments received in response to the notice of filing.
    Based on the aggregate exposure from food and feed commodities 
resulting from the use-patterns proposed in the petition, the proposed 
tolerances were revised to account for both tembotrione and its 
metabolite M5, expressed as tembotrione equilivants. The aggregate risk 
assessment is discussed in Unit III, below. The reasons for these 
changes are also explained in Unit V.

III. Aggregate Risk Assessment and Determination of Safety

    For tembotrione, aggregate exposure risk assessments were performed 
for the following scenarios: acute aggregate exposure (food and 
drinking water), and chronic aggregate exposure (food and drinking 
water). Short- and intermediate-term assessments were not performed 
because there are no registered or proposed residential non-food uses. 
The chronic Reference Dose (cRfD) will be protective of cancer and non-
cancer effects, because tembotrione is classified as ``Suggestive 
Evidence of Carcinogenicity'' and EPA's Cancer Assessment Review 
Committee (CARC ) recommended that a separate quantification of cancer 
risks is not required, while noting that the progression of non-
neoplastic related lesions in rats was biologically plausible by non-
genotoxic modes of action for the corneal tumors.
    Section 408(b)(2)(A)(i) of FFDCA allows EPA to establish a 
tolerance (the legal limit for a pesticide chemical residue in or on a 
food) only if EPA determines that the tolerance is ``safe.'' Section 
408(b)(2)(A)(ii) of FFDCA defines ``safe'' to mean that ``there is a 
reasonable certainty that no harm will result from aggregate exposure 
to the pesticide chemical residue, including all anticipated dietary 
exposures and all other exposures for which there is reliable 
information.'' This includes exposure through drinking water and in 
residential settings, but does not include occupational exposure. 
Section 408(b)(2)(C) of FFDCA requires EPA to give special 
consideration to exposure of infants and children to the pesticide 
chemical residue in establishing a tolerance and to ``ensure that there 
is a reasonable certainty that no harm will result to infants and 
children from aggregate exposure to the pesticide chemical 
residue....'' These provisions were added to FFDCA by the Food Quality 
Protection Act (FQPA) of 1996.
    Consistent with FFDCA section 408(b)(2)(D), and the factors 
specified in FFDCA 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 for the petitioned-for tolerance 
for combined residues of tembotrione, 2-[2-chloro-4-(methylsulfonyl)-3-
[(2,2,2-trifluoroethoxy]methyl]benzoyl]-1,3-cyclohexanedione and 
metabolite (M5), 2-[2-chloro-4-(methylsulfonyl)-3-[(2,2,2-
trifluoroethoxy)methyl]benzoyl]-4,6-dihydroxy-1,3-cyclohexanedione, in 
or on corn, field, grain at 0.02 ppm; corn, field, forage at 0.60 ppm; 
corn, field, stover at 0.45 ppm; corn, sweet, kernel plus cob with 
husks removed at 0.04 ppm; corn, sweet, forage at 1.0 ppm; corn, sweet, 
stover at 1.2 ppm; corn, pop, grain at 0.02 ppm; corn, pop, stover at 
0.35 ppm; cattle, liver at 0.40 ppm; cattle, meat byproducts, except 
liver 0.07 ppm; goat, liver at 0.40 ppm; goat, meat byproducts, except 
liver at 0.07 ppm; horse, liver at 0.40 ppm; horse, meat byproducts 
except liver at 0.07 ppm; sheep, liver at 0.40 ppm; sheep, meat 
byproducts, except liver at 0.07 ppm; poultry, liver at 0.07 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. Specific information on the studies received and the nature 
of the adverse effects caused by tembotrione, 2-[2-chloro-4-
(methylsulfonyl)-3-[(2,2,2-trifluoroethoxy)methyl]benzoyl]-1,3-
cyclohexanedione as well as the no-observed-adverse-effect-level 
(NOAEL) and the lowest-observed-adverse-effect-level (LOAEL) from the 
toxicity studies can be found at http://www.regulations.gov. The 

referenced document is available in the docket established by this 
action, which is described under ADDRESSES, and is identified as EPA-
HQ-OPP-2006-0072 in that docket.

B. Toxicological Endpoints

    For hazards that have a threshold below which there is no 
appreciable risk, the toxicological level of concern (LOC) is derived 
from the highest dose at which no adverse effects are observed (the 
NOAEL) in the toxicology study identified as appropriate for use in 
risk assessment. However, if a NOAEL cannot be determined, the lowest 
dose at which adverse effects of concern are identified (the LOAEL) is 
sometimes used for risk assessment. Uncertainty/safety factors (UFs) 
are used in conjunction with the LOC to take into account 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. Safety is assessed for acute and chronic 
risks by comparing aggregate exposure to the pesticide to the acute 
population adjusted dose (aPAD) and chronic population adjusted dose 
(cPAD). The aPAD and cPAD are calculated by dividing the LOC by all 
applicable UFs. Short-, intermediate-, and long-term risks are 
evaluated by comparing aggregate exposure to the LOC to ensure that the 
margin of exposure (MOE) called for by the product of all applicable 
UFs is not exceeded.
    For non-threshold risks, the Agency assumes that any amount of 
exposure will lead to some degree of risk and estimates risk in terms 
of the probability of occurrence of additional adverse cases. 
Generally, cancer risks are

[[Page 55080]]

considered non-threshold. For more information on the general 
principles EPA uses in risk characterization and a complete description 
of the risk assessment process, see http://www.epa.gov/fedrgstr/EPA-PEST/1997/November/Day-26/p30948.htm
.

    A summary of the toxicological endpoints for tembotrione, 2-[2-
chloro-4-(methylsulfonyl)-3-[(2,2,2-trifluoroethoxy)methyl]benzoyl]-
1,3-cyclohexanedione used for human risk assessment is shown in Table 1 
of this unit.

Table 1.--Summary of Toxicological Dose and Endpoints for tembotrione, 2-[2-chloro-4-(methylsulfonyl)-3-[(2,2,2-
              trifluoroethoxy)methyl]benzoyl]-1,3-cyclohexanedione for Use in Human Risk Assessment
----------------------------------------------------------------------------------------------------------------
                                          Dose Used in Risk
                                             Assessment,          Special FQPA SF and
          Exposure/Scenario                Interspecies and       Level of Concern for   Study and Toxicological
                                         Intraspecies and any       Risk Assessment              Effects
                                         Traditional FQPA, SF
----------------------------------------------------------------------------------------------------------------
Acute dietary (General population      LOAEL = 0.8 (mg/kg/day)  Special FQPA SF = 1      Developmental
 including infants and children) and   SF = 1000..............  aPAD = acute RfD /        Neurotoxicity Study:
 Females 13 to 49                      UFA = 10X..............   Special FQPA SF =        Offspring NOAEL was
                                       UFH = 10X..............   0.0008 mg/kg.            not
                                       FQPA SF = 10X(includes                             established.Offspring
                                        UFL = 10X).                                       LOAEL = 0.8 mg/kg/day
                                       Acute reference dose                               based on decreased
                                        (RfD) = 0.0008 mg/kg.                             acoustic startle
                                                                                          response on PND 60
                                                                                          (males), and brain
                                                                                          morphometric changes
                                                                                          on PND 75 (males and
                                                                                          females).
----------------------------------------------------------------------------------------------------------------
Chronic dietary(All populations)       NOAEL= .04 mg/kg/day     Special FQPA SF = 1      Chronic/Carcinogenicity
                                       SF = 100...............  cPAD = chronic RfD        Study LOAEL = 0.79 mg/
                                       UFA = 10X..............   Special FQPA SF =        kg/day based on
                                       UFH = 10X..............   0.0004 mg/kg/day.        neovascularization and
                                       FQPA SF = 1X...........                            edema of the cornea
                                       Chronic RfD = 0.0004 mg/                           and snow flake-like
                                        kg/day.                                           corneal opacity,
                                                                                          unilateral or
                                                                                          bilateral keratitis of
                                                                                          the eye, decreased
                                                                                          mean body weight and
                                                                                          mean body-weight gain,
                                                                                          increased total
                                                                                          cholesterol, higher
                                                                                          ketone levels and
                                                                                          lower pH values,
                                                                                          higher protein levels,
                                                                                          increased kidney
                                                                                          weight, kidney to body
                                                                                          weight and kidney to
                                                                                          brain weight ratios,
                                                                                          chronic nephropathy
                                                                                          and atrophy of the
                                                                                          sciatic nerve.
----------------------------------------------------------------------------------------------------------------
Short-term dermal (1 to 30 days)       Oral study LOAEL= 0.8    LOC for MOE =1000        Developmental
 (Residential)                          mg/kg/day                                         neurotoxicity Study
                                       UFA = 10X..............                            Offspring NOAEL was
                                       UFH = 10X..............                            not
                                       FQPA SF = 10X (includes                            established.Offspring
                                        UFL = 10X) (dermal                                LOAEL = 0.8 mg/kg/day
                                        absorption rate = 15                              based on decreased
                                        %).                                               acoustic startle
                                                                                          response on PND 60
                                                                                          (males), and brain
                                                                                          morphometric changes
                                                                                          on PND 75 (males and
                                                                                          females).
----------------------------------------------------------------------------------------------------------------
Intermediate-term dermal (1 to 6       Oral study LOAEL= 0.8    LOC for MOE = 1000       Developmental
 months) (Residential)                  mg/kg/day                (Residential)            neurotoxicity Study
                                       UFA = 10X..............                            Offspring NOAEL was
                                       UFH = 10X..............                            not
                                       FQPA SF = 10X (includes                            established.Offspring
                                        UFL = 10X) (dermal                                LOAEL = 0.8 mg/kg/day
                                        absorption rate = 15                              based on decreased
                                        %).                                               acoustic startle
                                                                                          response on PND 60
                                                                                          (males), and brain
                                                                                          morphometric changes
                                                                                          on PND 75 (males and
                                                                                          females).
----------------------------------------------------------------------------------------------------------------

[[Page 55081]]

Long-term dermal (>6 months to         Oral study NOAEL= 0.04   LOC for MOE = 100        Chronic/Carcinogenicity
 lifetime) (Residential)                mg/kg/day                (Residential)            Study LOAEL = 0.79 mg/
                                       UFA = 10X..............                            kg/day based on
                                       UFH = 10X..............                            neovascularization and
                                       FQPA SF = 1X (dermal                               edema of the cornea
                                        absorption rate = 15 %                            and snow flake-like
                                        when appropriate).                                corneal opacity,
                                                                                          unilateral or
                                                                                          bilateral keratitis of
                                                                                          the eye, decreased
                                                                                          mean body weight and
                                                                                          mean body-weight gain,
                                                                                          increased total
                                                                                          cholesterol, higher
                                                                                          ketone levels and
                                                                                          lower pH values,
                                                                                          higher protein levels,
                                                                                          increased kidney
                                                                                          weight, kidney to body
                                                                                          weight and kidney to
                                                                                          brain weight ratios,
                                                                                          chronic nephropathy
                                                                                          and atrophy of the
                                                                                          sciatic nerve.
----------------------------------------------------------------------------------------------------------------
Short-term inhalation (1 to 30 days)   Oral study LOAEL= 0.8    LOC for MOE = 1000       Developmental
 (Residential)                         UFL = 10X) (inhalation    (Residential)            neurotoxicity Study
                                        absorption rate =                                 Offspring NOAEL was
                                        100%).                                            not established.
                                                                                          Offspring LOAEL = 0.8
                                                                                          mg/kg/day based on
                                                                                          decreased acoustic
                                                                                          startle response on
                                                                                          PND 60 (males), and
                                                                                          brain morphometric
                                                                                          changes on PND 75
                                                                                          (males and females).
----------------------------------------------------------------------------------------------------------------
Intermediate-term inhalation (1 to 6   Oral study LOAEL= 0.8    LOC for MOE = 1000       Developmental
 months) (Residential)                  mg/kg/day                (Residential)            neurotoxicity Study]
                                       UFA = 10X..............                            Offspring NOAEL was
                                       UFH = 10X..............                            not
                                       FQPA SF = 10X (includes                            established.Offspring
                                        UFL = 10X) (inhalation                            LOAEL = 0.8 mg/kg/day
                                        absorption rate =                                 based on decreased
                                        100%).                                            acoustic startle
                                                                                          response on PND 60
                                                                                          (males), and brain
                                                                                          morphometric changes
                                                                                          on PND 75 (males and
                                                                                          females).
----------------------------------------------------------------------------------------------------------------
Long-term inhalation (>6 months)       Oral study NOAEL= 0.04   LOC for MOE = 100        Chronic/Carcinogenicity
 (Residential)                          mg/kg/day                Residential              Study LOAEL = 0.79 mg/
                                        UFH = 10X.............                            kg/day based on
                                       FQPA SF = 1X                                       neovascularization and
                                        (inhalation absorption                            edema of the cornea
                                        rate = 100%).                                     and snow flake-like
                                                                                          corneal opacity,
                                                                                          unilateral or
                                                                                          bilateral keratitis of
                                                                                          the eye, decreased
                                                                                          mean body weight and
                                                                                          mean body-weight gain,
                                                                                          increased total
                                                                                          cholesterol, higher
                                                                                          ketone levels and
                                                                                          lower pH values,
                                                                                          higher protein levels,
                                                                                          increased kidney
                                                                                          weight, kidney to body
                                                                                          weight and kidney to
                                                                                          brain weight ratios,
                                                                                          chronic nephropathy
                                                                                          and atrophy of the
                                                                                          sciatic nerve.
----------------------------------------------------------------------------------------------------------------
Cancer (Oral, dermal, inhalation)       Classification: ``Suggestive Evidence of Carcinogenic Potential'' based
                                         on the observance of squamous cell carcinomas in a rat carcinogenicity
                                                  study. Quantification of cancer risk is not required.
----------------------------------------------------------------------------------------------------------------
UF = uncertainty factor. UFA = extrapolation from animal to human (interspecies). UFH = potential variation in
  sensitivity among members of the human population (intraspecies). UFL = use of a LOAEL to extrapolate a NOAEL.
  MOE = margin of exposure. LOC = level of concern.

C. Exposure Assessment

    1. Dietary exposure from food and feed uses. In evaluating dietary 
exposure to tembotrione, 2-[2-chloro-4-(methylsulfonyl)-3-[(2,2,2-
trifluoroethoxy)methyl]benzoyl]-1,3-cyclohexanedione, EPA considered 
exposure under the petitioned-for tolerances. EPA assessed dietary 
exposures from tembotrione, 2-[2-chloro-4-(methylsulfonyl)-3-[(2,2,2-
tri

[[Page 55082]]

fluoroethoxy)methyl]benzoyl]-1,3-cyclohexanedione in food as follows:
    i. Acute exposure. Quantitative acute dietary exposure and 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.
    Effects were identified in the toxicological studies for 
tembotrione, 2-[2-chloro-4-(methylsulfonyl)-3-[(2,2,2-
trifluoroethoxy)methyl]benzoyl]-1,3-cyclohexanedione; therefore, a 
quantitative acute dietary exposure assessment was necessary. The acute 
analysis assumed 100% crop treated (CT), Dietary Exposure Evaluation 
Model (DEEM(TM)) 7.81 default processing factors, and 
tolerance-level residues for all foods. For drinking water, the entire 
distribution of estimated daily exposure values from the Pesticide Root 
Zone Modeling-Exposure Evaluation Analysis Modeling System (PRZM-EXAMS) 
run was incorporated in the acute probabilistic exposure analyses. The 
resulting acute dietary (food + water) risk estimates were < 32% of the 
aPAD for the general U.S. population and < 77% of the aPAD for all 
infants (< 1 year old, the most highly-exposed population subgroup) at 
the 95th percentile; less than HED's LOC (100% aPAD). Even though the 
entire distribution of estimated daily drinking water exposure values 
was incorporated, this analysis is still conservative since tolerance-
level residues, DEEM(TM) 7.81 default processing factors, 
and 100% CT were assumed. Also, the distribution of estimated daily 
drinking water exposure still assumes 100% CT and the maximum 
application rate.
    ii. Chronic exposure. In conducting the chronic dietary exposure 
assessment EPA used the food consumption data from the USDA, 1994-1996, 
and 1998 Continuing Survey of Food Intake by Individuals. As to residue 
levels in food, EPA assumed all foods for which there are proposed 
tolerances were treated and contain tolerance-level residues. A 
conservative chronic dietary assessment assuming tolerance-level 
residues, DEEM(TM) 7.81 default processing factors, and 100% 
CT was also conducted. The highest estimate of chronic surface water 
exposure (1.05 parts per billion (ppb)) was used for drinking water in 
this analysis.
    iii. Cancer. There was only suggestive evidence of carcinogenic 
potential based on the observance of squamous cell carcinomas in a rat 
carcinogenicity study. Quantification of cancer risk is not required. 
Dietary cancer risk concerns due to long-term consumption of 
tembotrione residues are adequately addressed by the chronic exposure 
analysis using the cPAD.
    2. Dietary exposure from drinking water. The Agency lacks 
sufficient monitoring data to complete a comprehensive dietary exposure 
analysis and risk assessment for tembotrione, 2-[2-chloro-4-
(methylsulfonyl)-3-[(2,2,2-trifluoroethoxy)methyl]benzoyl]-1,3-
cyclohexanedione 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 environmental fate characteristics of tembotrione, 2-[2-chloro-
4-(methylsulfonyl)-3-[(2,2,2-trifluoroethoxy)methyl]benzoyl]-1,3-
cyclohexanedione. Further, information regarding EPA drinking water 
models used in pesticide exposure assessment can be found at http://www.epa.gov/oppefed1/models/water/index.htm
.

    Based on the PRZM/EXAMS and Screening Concentration in Ground Water 
(SCI-GROW) models, the estimated environmental concentrations (EECs) of 
tembotrione, 2-[2-chloro-4-(methylsulfonyl)-3-[(2,2,2-
trifluoroethoxy)methyl]benzoyl]-1,3-cyclohexanedione for acute 
exposures are estimated to be 5.84 parts per billion (ppb) for surface 
water and 0.0139 ppb for ground water. The EECs for chronic exposures 
are estimated to be 1.05 ppb for surface water and 0.0139 ppb for 
ground water.
    Modeled estimates of drinking water concentrations were directly 
entered into the dietary exposure model. For acute dietary risk 
assessment, the water concentration value of 5.84 ppb was used to 
access the contribution to drinking water. For chronic dietary risk 
assessment, the water concentration of value 1.05 ppb was used to 
access the contribution to drinking 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).
    Tembotrione, 2-[2-chloro-4-(methylsulfonyl)-3-[(2,2,2-
trifluoroethoxy)methyl]benzoyl]-1,3-cyclohexanedione is not registered 
for use on any sites that would result in residential exposure.
    4. Cumulative effects from substances with a common mechanism of 
toxicity. Section 408(b)(2)(D)(v) of FFDCA requires that, when 
considering whether to establish, modify, or revoke a tolerance, the 
Agency consider ``available information'' concerning the cumulative 
effects of a particular pesticide's residues and ``other substances 
that have a common mechanism of toxicity.''
    Tembotrione, belongs to a class of herbicides (including 
mesotrione, pyrasulfotole, isoxaflutole and topramezone) that inhibit 
the liver enzyme 4-hydroxyphenylpyruvate dioxygenase (HPPD). As 
discussed above, EPA has concluded that the ocular effects caused by 
these herbicides has limited relevance to humans. Nonetheless, as a 
worst case scenario, EPA has assessed aggregate exposure to tembotrione 
based on ocular effects in rats. For similar reasons, a semi-
quantitative screening cumulative assessment was conducted using the 
rat ocular effects and 100% crop treated information. The results of 
this screening analysis did not indicate a concern. In the future, 
assessments of HPPD-inhibiting herbicides will consider more 
appropriate models and cross species extrapolation methods.
    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 EPA's website at http://www.epa.gov/pesticides/cumulative
.

D. Safety Factor for Infants and Children

    1.In general. Section 408 of FFDCA provides that EPA shall apply an 
additional (``10X'') tenfold margin of safety for infants and children 
in the case of threshold effects to account for pre- and post-natal 
toxicity and the completeness of the database on toxicity and exposure 
unless EPA determines based on reliable data that a different margin of 
safety will be safe for infants and children. This additional margin of 
safety is commonly referred to as the FQPA safety factor. In applying 
this provision, EPA either retains the default value of 10X when 
reliable data do not support the choice of a different factor, or, if 
reliable data are available, EPA uses a different additional FQPA 
safety factor value based on the use of traditional UFs and/or special 
FQPA safety factors, as appropriate.
    2. Prenatal and postnatal sensitivity. There is evidence of 
increased susceptibility in rabbit and rat fetuses to in utero exposure 
to tembotrione compared to the doses for the effects found in maternal 
animals. In a developmental toxicity study in rabbits, the NOAEL of 1 
milligram per kilogram of body weight per day (mg/kg bw/day) was based 
on decreased growth and/or delayed development of the skeleton

[[Page 55083]]

and increased incidences of skeletal variations and anomalies in 
fetuses seen at a LOAEL of 10 mg/kg/day. This LOAEL is ten-fold lower 
than the dose resulting in maternal toxicity (100 mg/kg/day, few or no 
feces, late abortion, decreased body weight and food consumption). In a 
rat developmental toxicity study, increased skeletal variations (e.g., 
delayed ossifications) and other fetal effects (decreased fetal body 
weights and an increased number of runts) occurred at a dose of 25 mg/
kg/day (the lowest dose tested), which is lower than the 125 mg/kg bw 
dose that caused marginal maternal toxicity (decreased body-weight 
gains and food consumption). In a rat developmental neurotoxicity study 
(DNT), decreased post-weaning body weight (males), decreased acoustic 
startle response and brain morphometric changes were seen in rat 
fetuses at a dose of 0.8 mg/kg/day (the lowest dose tested) which was 
lower than the dose of 16.3 mg/kg/day at which maternal toxicity 
occurred (cornel opacity during lactation).
    Although, these studies provide evidence of increased 
susceptibility following pre- and post-natal exposures, the concern for 
increased susceptibility is low for several reasons. First, a well 
characterized NOAEL (with a sufficient margin from the LOAEL) 
protecting fetuses has been established in the rabbit prenatal study. 
Also, the prenatal developmental NOAELs or LOAELs for both the rabbit 
and rat studies are approximately 12 to 30-fold higher than the LOAEL 
used for the acute RfD. Although there were some marginal effects 
reported in the offspring in the rat 2-generation reproduction study at 
1.4 mg/kg/day (the lowest dose tested), these parameters (ocular, 
decreased absolute brain weight, preputial separation) were also 
evaluated at the lower dose in the rat DNT study but were not found at 
the low dose tested (0.8 mg/kg/day). Therefore, a NOAEL has been 
identified for these effects. Other effects indicative of neurotoxicity 
(altered brain morphometrics, decrease in auditory startle response) 
were seen in the rat developmental neurotoxicity study at the lowest 
dose tested. The response for brain morphometrics seen at termination 
is considered to be marginal or equivocal since the changes were small 
and no clear dose response was observed. The decreased acoustic startle 
response was not found in young pups (post-natal day 22) but only 
observed in adult rats (post-natal day 60) and was statistically 
significant at the mid and high dose but not at the lowest dose tested.
    3. Conclusion. Given the above-described data on pre- and post-
natal effects, the only significant uncertainty concerns the acute RfD 
due to the failure to identify a NOAEL for the brain morphometric 
alterations found in the rat DNT. The LOAEL in the DNT is lower than 
the NOAEL and the LOAEL from the rabbit and rat developmental studies, 
and thus is the lowest dose reflective of potential acute effects. 
Because of the uncertainty as to the NOAEL for the acute effects (brain 
morphometric alterations) seen at 0.8 mg/kg/day in the DNT, EPA has 
retained the additional 10X FQPA safety factor in calculating the acute 
RfD. This is a conservative step given the equivocal nature of the 
brain morphometric alterations seen at the LOAEL in the DNT.
    EPA has determined that reliable data show that it would be safe 
for infants and children to reduce the FQPA safety factor to 1X for 
assessing chronic risk. That decision is based on the following 
findings:
    i. For the reasons described in Unit III.D.2., the toxicity 
database for tembotrione, 2-[2-chloro-4-(methylsulfonyl)-3-[(2,2,2-
trifluoroethoxy)methyl]benzoyl]-1,3-cyclohexanedione is adequate to 
assess chronic risk.
    ii. Despite evidence of sensitivity in pre- and post-natal studies, 
as detailed in Unit III.D.2., the chronic RfD based on an adult animal 
study (chronic rat study) is considered to be protective of the chronic 
offspring toxicity found in the rat DNT and 2-generation reproduction 
studies. The 2-generation reproduction study did not identify a NOAEL 
for the chronic effects seen on brain weight and preputial separation 
but a NOAEL can be characterized from the DNT, as discussed above, at 
0.8 mg/kg/day. The NOAEL used to set the chronic RfD is 20-fold lower 
than this 0.8 mg/kg/day dose and is not based on an effect as to which 
the data have raised sensitivity concerns. Similarly, the chronic rat 
study and the NOAEL from that study are protective of the chronic 
effects seen in the DNT study and the other chronic effects found in 
the 2-generation reproduction study. The endpoints of concern for the 
chronic RfD are based on ocular toxicity, body weight decreases, kidney 
toxicity, and changes in the clinical chemistry parameters. Target 
organ toxicity such as ocular toxicity, kidney toxicity, body weight 
changes and nervous system effects were assessed in the young through 
pre- and post-natal exposure to tembotrione in the 2-generation 
reproduction study and the DNT study. In those studies, these effects 
were observed at higher doses in the young than in the adults in the 
chronic rat study. Therefore, the chronic RfD is considered to be 
protective of effects in the young. As noted, the NOAEL (0.04 mg/kg/
day) selected for the chronic RfD is 20-fold lower than the dose at 
which developmental and neurological effects were observed in any 
study; it is also 20-fold lower than the NOAEL for other chronic 
effects seen in the young.
    iii. There are no residual uncertainties identified in the exposure 
data bases. The dietary food exposure assessments were performed based 
on 100% CT and tolerance-level residues of tembotrione, 2-[2-chloro-4-
(methylsulfonyl)-3-[(2,2,2-trifluoroethoxy)methyl]benzoyl]-1,3-
cyclohexanedione.

E. Aggregate Risks and Determination of Safety

    Safety is assessed for acute and chronic risks by comparing 
aggregate exposure to the pesticide to the aPAD and cPAD. The aPAD and 
cPAD are calculated by dividing the LOC by all applicable UFs. For 
linear cancer risks, EPA calculates the probability of additional 
cancer cases given aggregate exposure. Short-, intermediate-, and long-
term risks are evaluated by comparing aggregate exposure to the LOC to 
ensure that the MOE called for by the product of all applicable UFs is 
not exceeded.
    1. Acute risk. Using the exposure assumptions discussed in this 
unit for acute exposure, the acute dietary exposure from food and water 
to tembotrione, 2-[2-chloro-4-(methylsulfonyl)-3-[(2,2,2-
trifluoroethoxy)methyl]benzoyl]-1,3-cyclohexanedione will occupy 77% of 
the aPAD for the population group (infants (< 1 year old) receiving the 
greatest exposure.
    2. Chronic risk. Using the exposure assumptions described in this 
unit for chronic exposure, EPA has concluded that exposure to 
tembotrione, 2-[2-chloro-4-(methylsulfonyl)-3-[(2,2,2-
trifluoroethoxy)methyl]benzoyl]-1,3-cyclohexanedione from food and 
water will utilize 48% of the cPAD for the population group (children 3 
to 5 years old). There are no residential uses for tembotrione, 2-[2-
chloro-4-(methylsulfonyl)-3-[(2,2,2-trifluoroethoxy)methyl]benzoyl]-
1,3-cyclohexanedione that result in chronic residential exposure to 
tembotrione, 2-[2-chloro-4-(methylsulfonyl)-3-[(2,2,2-
trifluoroethoxy)methyl]benzoyl]-1,3-cyclohexanedione.
    3. Short-term risk. Short-term aggregate exposure takes into 
account residential exposure plus chronic exposure to food and water 
(considered to be a background exposure level).

[[Page 55084]]

    Tembotrione, 2-[2-chloro-4-(methylsulfonyl)-3-[(2,2,2-
trifluoroethoxy)methyl]benzoyl]-1,3-cyclohexanedione is not registered 
for use on any sites that would result in residential exposure. 
Therefore, the aggregate risk is the sum of the risk from food and 
water, which does not exceed the Agency's level of concern.
    4. Intermediate-term risk. Intermediate-term aggregate exposure 
takes into account residential exposure plus chronic exposure to food 
and water (considered to be a background exposure level).
    Tembotrione, 2-[2-chloro-4-(methylsulfonyl)-3-[(2,2,2-
trifluoroethoxy)methyl]benzoyl]-1,3-cyclohexanedione is not registered 
for use on any sites that would result in residential exposure. 
Therefore, the aggregate risk is the sum of the risk from food and 
water, which does not exceed the Agency's level of concern.
    5. Aggregate cancer risk for U.S. population. Dietary cancer risk 
concerns due to long-term consumption of tembotrione residues are 
adequately addressed by the chronic exposure analysis using the cPAD.
    6. Determination of safety. Based on these risk assessments, EPA 
concludes that there is a reasonable certainty that no harm will result 
to the general population, or to infants and children from aggregate 
exposure to tembotrione, 2-[2-chloro-4-(methylsulfonyl)-3-[(2,2,2-
trifluoroethoxy)methyl]benzoyl]-1,3-cyclohexanedione residues.

IV. Other Considerations

A. Analytical Enforcement Methodology

    An Adequate enforcement methodology, liquid chromatography/mass 
spectroscopy (LC/MS/MS) method is available to enforce the tolerance 
expression. The method may be requested from: Chief, Analytical 
Chemistry Branch, Environmental Science Center, 701 Mapes Rd., Ft. 
Meade, MD 20755-5350; telephone number (410) 305-2905; e-mail address: 
residuemethods@epa.gov.

B. International Residue Limits

    There is neither a Codex proposal, nor Canadian or Mexican limits 
for residues of tembotrione and its metabolites in or on crops or 
livestock commodities.

C. Response to Comments

    There were no comments received on the Notice of Filing of the 
pesticide petition.

V. Conclusion

    Therefore, the tolerance is established for combined residues or 
residues of tembotrione, 2-[2-chloro-4-(methylsulfonyl)-3-[(2,2,2-
(trifluoroethoxy)methyl]benzoyl]-1,3-cyclohexanedione, metabolite; 2-
[2-chloro-4-(methylsulfonyl)-3-[(2,2,2-trifluorethoxy)methyl]benzoyl]-
4,6-dihydroxycyclohexanedione, in or on corn, field, grain at 0.02 ppm; 
corn, field, forage at 0.60 ppm; corn, field, stover at 0.45 ppm; corn, 
sweet, kernel plus cob with husks removed at 0.04 ppm; corn, sweet, 
forage at 1.0 ppm; corn sweet, stover at 1.2 ppm; corn, pop, grain at 
0.02 ppm; corn, pop, stover at 0.35 ppm; cattle, liver at 0.40 ppm; 
cattle, meat byproducts, except liver 0.07 ppm; goat, liver at 0.40 
ppm; goat, meat byproducts, except liver at 0.07 ppm; horse, liver at 
0.40 ppm; horse, meat byproducts except liver at 0.07 ppm; sheep, liver 
at 0.40 ppm; sheep, meat byproducts, except liver at 0.07 ppm; poultry, 
liver at 0.07 ppm.

VI. Statutory and Executive Order Reviews

    This final rule establishes a tolerance under section 408(d) of 
FFDCA in response to a petition submitted to the Agency. The Office of 
Management and Budget (OMB) has exempted these types of actions from 
review under Executive Order 12866, entitled Regulatory Planning and 
Review (58 FR 51735, October 4, 1993). Because this rule has been 
exempted from review under Executive Order 12866, 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) or Executive Order 13045, entitled Protection of Children 
from Environmental Health Risks and Safety Risks (62 FR 19885, April 
23, 1997). 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., 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).
    Since tolerances and exemptions that are established on the basis 
of a petition under section 408(d) of FFDCA, such as the tolerance in 
this final rule, do not require the issuance of a proposed rule, the 
requirements of the Regulatory Flexibility Act (RFA) (5 U.S.C. 601 et 
seq.) do not apply.
    This final rule directly regulates growers, food processors, food 
handlers, and food retailers, not States or tribes, nor does this 
action alter the relationships or distribution of power and 
responsibilities established by Congress in the preemption provisions 
of section 408(n)(4) of FFDCA. As such, the Agency has determined that 
this action will not have a substantial direct effect on States or 
tribal governments, on the relationship between the national government 
and the States or tribal governments, or on the distribution of power 
and responsibilities among the various levels of government or between 
the Federal Government and Indian tribes. Thus, the Agency has 
determined that Executive Order 13132, entitled Federalism (64 FR 
43255, August 10, 1999) and Executive Order 13175, entitled 
Consultation and Coordination with Indian Tribal Governments (65 FR 
67249, November 6, 2000) do not apply to this rule. In addition, This 
rule does not 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).
    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).

VII. Congressional Review Act

    The Congressional Review Act, 5 U.S.C. 801 et seq., generally 
provides that before a rule may take effect, the agency promulgating 
the rule must submit a rule report 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: September 23, 2007.
Debra Edwards,
Director, Office of Pesticide Programs.

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

PART 180--[AMENDED]

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

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

[[Page 55085]]

0
2. Section 180.634 is added to subpart C to read as follows:

Sec. 180.634  Tembotrione; tolerances for residues.

    (a) General. Tolerances are established for residues of the 
herbicide, tembotrione, 2-[2-chloro-4-(methylsulfonyl)-3-[(2,2,2-
trifluoroethoxy)methyl]benzoyl]-1,3-cyclohexanedione and its metabolite 
2-[2-chloro-4-(methylsulfonyl)-3-[(2,2,2-
trifluoroethoxy)methyl]benzoyl]-4,6-dihydroxycyclohexane-1,3-dione in 
or on the following commodities:

------------------------------------------------------------------------
                                                             Parts per
                        Commodity                             million
------------------------------------------------------------------------
Cattle, liver...........................................            0.40
Cattle, meat byproducts, except liver...................            0.07
Corn, field, forage.....................................            0.60
Corn, field, grain......................................            0.02
Corn, field, stover.....................................            0.45
Corn, pop, grain........................................            0.02
Corn, pop, stover.......................................            0.35
Corn, sweet, forage.....................................             1.0
Corn, sweet, kernel plus cob with husks removed.........            0.04
Corn, sweet, stover.....................................             1.2
Goat, liver.............................................            0.40
Goat, meat byproducts, except liver.....................            0.07
Horse, liver............................................            0.40
Horse, meat byproducts, except liver....................            0.07
Poultry, liver..........................................            0.07
Sheep, liver............................................            0.40
Sheep, meat byproducts, except liver....................            0.07
------------------------------------------------------------------------

    (b) Section 18 emergency exemptions. [Reserved]
    (c) Tolerances with regional registrations. [Reserved]
    (d) Indirect or inadvertent residues. [Reserved]
[FR Doc. E7-19230 Filed 9-27-07; 8:45 am]

BILLING CODE 6560-50-S