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Hexythiazox; Pesticide Tolerances

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PDF Version (6 pp, 124K, About PDF)

[Federal Register: May 28, 2008 (Volume 73, Number 103)]
[Rules and Regulations]
[Page 30498-30503]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr28my08-13]

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ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 180
[EPA-HQ-OPP-2005-0309; FRL-8365-2]

Hexythiazox; Pesticide Tolerances

AGENCY: Environmental Protection Agency (EPA).
ACTION: Final rule.

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SUMMARY: This regulation establishes tolerances for combined residues
of hexythiazox in or on corn, field, grain; corn, field, stover; and
corn, field, forage. Gowan Company requested these tolerances under the
Federal Food, Drug, and Cosmetic Act (FFDCA).

DATES: This regulation is effective May 28, 2008. Objections and
requests for hearings must be received on or before July 28, 2008, 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-2005-0309. 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

[[Page 30499]]

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: Olga Odiott, Registration Division
(7505P), Office of Pesticide Programs, Environmental Protection Agency,
1200 Pennsylvania Ave., NW., Washington, DC 20460-0001; telephone
number: (703) 308-9369; e-mail address: odiott.olga@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).
    • Animal production (NAICS code 112).
    • Food manufacturing (NAICS code 311).
    • Pesticide manufacturing (NAICS code 32532).
    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-2005-0309 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 July 28, 2008.
    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-2005-0309, 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.

II. Petition for Tolerance

    In the Federal Register of March 1, 2006 (71 FR 10506) (FRL-7756-4), 
EPA issued a notice pursuant to section 408(d)(3) of FFDCA, 21
U.S.C. 346a(d)(3), announcing the filing of a pesticide petition (PP
5F6953) by Gowan Company, 370 South Main Street, Yuma, AZ 85364. The
petition requested that 40 CFR 180.448 be amended by establishing
tolerances for combined residues of the insecticide hexythiazox, trans-
5-(4-chlorophenyl)-N-cyclohexyl-4-methyl-2-oxothiazolidine-3-
carboxamide and its metabolites containing the (4-chlorophenyl)-4-
methyl-2-oxo-3-thiazolidine moiety, in or on corn, field, grain at 0.05
parts per million (ppm); corn, field, stover at 2.0 ppm; and corn,
field, forage at 2.0 ppm. That notice referenced a summary of the
petition prepared by Gowan Company, the registrant, which is available
to the public in the docket, http://www.regulations.gov. Comments were
received on the notice of filing. EPA's response to these comments is
discussed in Unit IV.C.
    Based upon review of the data supporting the petition, EPA has
revised the tolerance levels to 0.02 ppm for corn, field, grain; 2.5
ppm for corn, field, stover; and 6.5 ppm for corn, field, forage. The
reasons for these changes are explained in Unit IV.D.

III. Aggregate Risk Assessment and Determination of Safety

    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....''
    Consistent with section 408(b)(2)(D) of FFDCA, and the factors
specified in section 408(b)(2)(D) of FFDCA, EPA has reviewed the
available scientific data and other relevant information in support of
this action. EPA has sufficient data to assess the hazards of and to
make a determination on aggregate exposure for the petitioned-for
tolerances for combined residues of hexythiazox on corn, field, grain
at 0.02 ppm; corn, field, stover at 2.5 ppm; and corn, field, forage at
6.0 ppm. EPA's assessment of exposures and risks associated with
establishing tolerances follows.

[[Page 30500]]

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.
    Hexythiazox has a low order of acute toxicity for the oral, dermal
and inhalation routes of exposure. It produces mild eye irritation, is
not a dermal irritant, and is negative for dermal sensitization. The
target organs of hexythiazox are the liver and adrenal glands, with the
dog being the most sensitive species. In a subchronic toxicity study in
rats, increased liver and adrenal weights as well as adrenal
histopathology (fatty degeneration of the adrenal zone fasciculata)
were seen. In a 4-week range-finding study in dogs, effects included
increased liver and adrenal weights (reported in the chronic dog
study). Chronic studies in dogs, rats, and mice support the liver and
adrenal effects seen in the subchronic studies. In the chronic dog
study, increased liver and adrenal weights were observed, along with
associated histopathology of the liver (hypertrophy) and adrenal glands
(adrenal cortex hypertrophy). In the chronic feeding/carcinogenicity
studies in rats and mice, effects included decreased body weight gain
and increased liver weights. The effects of hexythiazox on the adrenal
glands could be an indication of endocrine disruption. However, in all
studies in which these effects were seen, a NOAEL was determined. The
data provided no indication of increased susceptibility in rats or
rabbits from in utero and post-natal exposure to hexythiazox. There was
no evidence of carcinogenicity in male and female rats; however, there
were increased incidences of malignant and combined benign/malignant
liver tumors in female B6C3FT mice. Hexythiazox was not mutagenic in
bacteria or Chinese hamster ovary (CHO) cells. It was negative for
chromosomal aberrations in CHO and did not cause unscheduled DNA
synthesis (UDS) in primary rat hepatocytes. In an acceptable
micronucleus assay, there was no statistically significant increase in
the frequency of micronucleated polychromatic erythrocytes in bone
marrow of treated mice after any dose or treatment time. Hexythiazox
has been found classified as nonmutagenic.
    Specific information on the studies received and the nature of the
adverse effects caused by hexythiazox as well as the no-observed-
adverse-effect-level (NOAEL) and the lowest-observed-adverse-effect-
level (LOAEL) from the toxicity studies are discussed in the final rule
published in the Federal Register of December 30, 2005 (70 FR 77363)
(FRL-7752-1).

B. Toxicological Endpoints

    For hazards that have a threshold below which there is no
appreciable risk, a toxicological point of departure (POD) is
identified as the basis for derivation of reference values for risk
assessment. The POD may be defined as 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) or a Benchmark Dose (BMD) approach
is sometimes used for risk assessment. Uncertainty/safety factors (UFs)
are used in conjunction with the POD 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
dietary risks by comparing aggregate food and water 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 POD by all applicable UFs. Aggregate short-, intermediate-
, and chronic-term risks are evaluated by comparing food, water, and
residential exposure to the POD to ensure that the margin of exposure
(MOE) called for by the product of all applicable UFs is not exceeded.
This latter value is referred to as the Level of Concern (LOC).
    For non-threshold risks, the Agency assumes that any amount of
exposure will lead to some degree of risk. Thus, the Agency estimates
risk in terms of the probability of an occurrence of the adverse effect
greater than that expected in a lifetime. 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/pesticides/factsheets/riskassess.htm.
    A summary of the toxicological endpoints for hexythiazox used for
human risk assessment can be found at http://www.regulations.gov in
document Hexythiazox- Human Health Risk Assessment for the Section 3
Registration for Application to Field Corn; 14- February-2008, page 11
in docket ID number EPA-HQ-OPP-2005-0309.

C. Exposure Assessment

    1. Dietary exposure from food and feed uses. In evaluating dietary
exposure to hexythiazox, EPA considered exposure under the petitioned-
for tolerances as well as all existing hexythiazox tolerances in (40
CFR 180.448). EPA assessed dietary exposures from hexythiazox 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.
    In estimating acute dietary exposure, EPA used food consumption
information from the United States Department of Agriculture (USDA)
1994-1996 and 1998 Nationwide Continuing Surveys of Food Intake by
Individuals (CSFII). As to residue levels in food, EPA tolerance-level
residues, 100% crop treated (PCT), and DEEM-FCID\\ (ver 7.81) default
processing factors for all plant and livestock residues.
    ii. Chronic exposure. In conducting the chronic dietary exposure
assessment EPA used the food consumption data from the USDA 1994-1996
and 1998 CSFII. As to residue levels in food, EPA used PCT estimates,
average field trial residues, experimentally determined processing
factors when available, and anticipated livestock residues (dietary
burden calculated using average field trial residues).
    iii. Cancer. Cancer risk was assessed using the same estimates as
discussed in Unit III.C.1.ii., chronic exposure.
    iv. Anticipated residue and PCT information.Section 408(b)(2)(E) of
FFDCA authorizes EPA to use available data and information on the
anticipated residue levels of pesticide residues in food and the actual
levels of pesticide residues that have been measured in food. If EPA
relies on such information, EPA must require pursuant to FFDCA section
408(f)(1) that data be provided 5 years after the tolerance is
established, modified, or left in effect, demonstrating that the levels
in food are not above the levels anticipated. For the present action,
EPA will issue such data call-ins as are required by FFDCA section
408(b)(2)(E) and authorized under FFDCA section 408(f)(1). Data will be
required to be submitted no later than 5 years from the date of
issuance of these tolerances.

[[Page 30501]]

    Section 408(b)(2)(F) of FFDCA states that the Agency may use data
on the actual percent of food treated for assessing chronic dietary
risk only if:
     Condition a. The data used are reliable and provide a valid basis
to show what percentage of the food derived from such crop is likely to
contain the pesticide residue.
     Condition b. The exposure estimate does not underestimate exposure
for any significant subpopulation group.
     Condition c. Data are available on pesticide use and food
consumption in a particular area, the exposure estimate does not
understate exposure for the population in such area.
In addition, the Agency must provide for periodic evaluation of any
estimates used. To provide for the periodic evaluation of the estimate
of PCT as required by FFDCA section 408(b)(2)(F), EPA may require
registrants to submit data on PCT.
    The Agency used PCT information as follows:
    1% for apples, cherries, and prunes; 5% for almonds, apricots,
mint, peaches, pears, plums, and walnuts; 10% for dates, caneberries,
and nectarines; 25% for strawberries; and 50% for hops.
    In most cases, EPA uses available data from United States
Department of Agriculture/National Agricultural Statistics Service
(USDA/NASS), proprietary market surveys, and the National Pesticide Use
Database for the chemical/crop combination for the most recent 6 years.
EPA uses an average PCT for chronic dietary risk analysis. The average
PCT figure for each existing use is derived by combining available
public and private market survey data for that use, averaging across
all observations, and rounding to the nearest 5%, except for those
situations in which the average PCT is less than one. In those cases,
1% is used as the average PCT and 2.5% is used as the maximum PCT. EPA
uses a maximum PCT for acute dietary risk analysis. The maximum PCT
figure is the highest observed maximum value reported within the recent
6 years of available public and private market survey data for the
existing use and rounded up to the nearest multiple of 5%.
    The Agency used projected percent crop treated (PPCT) information
as follows:
    15% for grapes and 18% for oranges.
    EPA estimates PPCT for a new pesticide use by assuming that the PCT
during the pesticide's initial five years of use on a specific site
will not exceed the average PCT of the dominant pesticide (i.e., the
one with the greatest PCT) on that site over the most recent surveys.
Comparisons are only made among pesticides of the same pesticide types
(i.e., the dominant insecticide on the use site is selected for
comparison with a new insecticide). The PCTs included in the average
may be each for the same pesticide or for different pesticides since
the same or different pesticides may dominate for each year selected.
Typically, EPA uses USDA/NASS as the source for raw PCT data because it
is publicly available and does not have to be calculated from other
available data sources. When a specific use site is not surveyed by
USDA/NASS, EPA uses proprietary data and calculates the estimated PCT.
    This estimated PPCT, based on the average PCT of the market leader,
is appropriate for use in the chronic dietary risk assessment. This
method of estimating a PPCT for a new use of a registered pesticide or
a new pesticide produces a high-end estimate that is unlikely, in most
cases, to be exceeded during the initial five years of actual use. The
predominant factor that bears on whether the estimated PPCT could be
exceeded is whether there are concerns with pest pressures as indicated
in emergency exemption requests or other readily available information.
All information currently available has been considered for
hexythiazox, and it is the opinion of EPA that it is unlikely that the
actual PCT for hexythiazox will exceed the estimated PPCT during the
next five years.
    The Agency believes that the three conditions discussed in Unit
III.C.1.iv. have been met. With respect to Condition a, PCT estimates
are derived from Federal and private market survey data, which are
reliable and have a valid basis. The Agency is reasonably certain that
the percentage of the food treated is not likely to be an
underestimation. As to Conditions b and c, regional consumption
information and consumption information for significant subpopulations
is taken into account through EPA's computer-based model for evaluating
the exposure of significant subpopulations including several regional
groups. Use of this consumption information in EPA's risk assessment
process ensures that EPA's exposure estimate does not understate
exposure for any significant subpopulation group and allows the Agency
to be reasonably certain that no regional population is exposed to
residue levels higher than those estimated by the Agency. Other than
the data available through national food consumption surveys, EPA does
not have available reliable information on the regional consumption of
food to which hexythiazox may be applied in a particular area.
    2. Dietary exposure from drinking water. The Agency used screening
level water exposure models in the dietary exposure analysis and risk
assessment for hexythiazox in drinking water. These simulation models
take into account data on the physical, chemical, and fate/transport
characteristics of hexythiazox. 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 Pesticide Root Zone Model /Exposure Analysis Modeling
System (PRZM/EXAMS) and Screening Concentration in Ground Water (SCI-
GROW) models, the estimated drinking water concentrations (EDWCs) of
hexythiazox
    1. The EDWCs for acute exposures are estimated to be 4.23 parts per
billion (ppb) for surface water and 0.00503 ppb for ground water.
    2. The EDWCs for chronic exposures for non-cancer assessments are
estimated to be 2.26 ppb for surface water and 0.00503 ppb for ground
water.
    3. The EDWCs for chronic exposures for cancer assessments are
estimated to be 1.72 ppb for surface water and 0.00503 ppb for ground
water.
    Modeled estimates of drinking water concentrations were directly
entered into the dietary exposure model.
    1. For acute dietary risk assessment, the water concentration value
of 4.23 ppb was used to assess the contribution to drinking water.
    2. For chronic dietary risk assessment, the water concentration of
value 2.26 ppb was used to assess the contribution to drinking water.
    3. For cancer dietary risk assessment, the water concentration of
value 1.72 ppb was used to assess 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).
    Hexythiazox is not registered for any specific use patterns 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

[[Page 30502]]

substances that have a common mechanism of toxicity.''
    EPA has not found hexythiazox to share a common mechanism of
toxicity with any other substances, and hexythiazox does not appear to
produce a toxic metabolite produced by other substances. For the
purposes of this tolerance action, therefore, EPA has assumed that
hexythiazox does not have 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 EPA's website at 
http://www.epa.gov/pesticides/cumulative.

D. Safety Factor for Infants and Children

    1. In general. Section 408(b)(2)(c) of FFDCA provides that EPA
shall apply an additional tenfold (10X) margin of safety for infants
and children in the case of threshold effects to account for prenatal
and postnatal toxicity and the completeness of the database on toxicity
and exposure unless EPA determines based on reliable data that a
different margin of safety will be safe for infants and children. This
additional margin of safety is commonly referred to as the FQPA safety
factor (SF). In applying this provision, EPA either retains the default
value of 10X, or uses a different additional safety factor when reliable
data available to EPA support the choice of a different factor.
    2. Prenatal and postnatal sensitivity. The prenatal and postnatal
toxicology data base indicates no increased susceptibility of rats or
rabbits to in utero and/or postnatal exposure to hexythiazox.
    3. Conclusion. EPA has determined that reliable data show the
safety of infants and children would be adequately protected if the FQPA
SF were reduced to 1X. That decision is based on the following findings:
    i. The toxicity database for hexythiazox is adequate for selecting
toxicity endpoints for risk assessment. The toxicity profile of
hexythiazox can be characterized for all effects, including potential
developmental, reproductive, and neurotoxic effects.
    ii. There is no evidence that hexythiazox is a neurotoxic chemical
and there is no need for a developmental neurotoxicity study or
additional UFs to account for neurotoxicity.
    iii. There is no evidence that hexythiazox results in increased
susceptibility in in utero rats or rabbits in the prenatal developmental
studies or in young rats in the 2-generation reproduction study.
    iv. The concern for endocrine related effects (increase in ovarian
weight and adrenal weights and/or adrenal pathology) seen in various
species is low because there is a well established NOAEL protecting
from the effects, no reproductive parameters were affected in the 2-
generation reproduction study at the highest dose tested (180 mg/kg/
day), there is no evidence of increased susceptibility of infants and
children in the database and the doses selected for the cRfD and
intermediate and long-term dermal and inhalation exposure assessments
are based on the NOAELs protecting from the endocrine related effects.
EPA concluded that the selected endpoints adequately account for these
potential effects and no additional data are required.
    v. There are no residual uncertainties identified in the exposure
databases. Although the chronic food exposure assessment is refined,
EPA believes that the assessment is based on reliable data and will not
underestimate exposure/risk. EPA made conservative (protective)
assumptions in the ground and surface water modeling used to assess
exposure to hexythiazox in drinking water. These assessments will not
underestimate the exposure and risks posed by hexythiazox.

E. Aggregate Risks and Determination of Safety

    EPA determines whether acute and chronic pesticide exposures are
safe by comparing aggregate exposure estimates to the aPAD and cPAD.
The aPAD and cPAD represent the highest safe exposures, taking into
account all appropriate SFs. EPA calculates the aPAD and cPAD by
dividing the POD by all applicable UFs. For linear cancer risks, EPA
calculates the probability of additional cancer cases given the
estimated aggregate exposure. Short-, intermediate-, and chronic-term
risks are evaluated by comparing the estimated aggregate food, water,
and residential exposure to the POD 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 hexythiazox will occupy <1% of the aPAD for (females 13-49 years
old) the population group receiving the greatest exposure.
    2. Chronic risk. Using the exposure assumptions described in this
unit for chronic exposure, EPA has concluded that chronic exposure to
hexythiazox from food and water will utilize 1% of the cPAD for
(children 1-2 years old) the population group receiving the greatest
exposure. There are no residential uses for hexythiazox.
    3. Short-term risk. Short-term aggregate exposure takes into
account short-term residential exposure plus chronic exposure to food
and water (considered to be a background exposure level).
    Hexythiazox is not registered for any use patterns that would
result in residential exposure. Therefore, the short-term aggregate
risk is the sum of the risk from exposure to hexythiazox through food
and water and will not be greater than the chronic aggregate risk.
    4. Intermediate-term risk. Intermediate-term aggregate exposure
takes into account intermediate-term residential exposure plus chronic
exposure to food and water (considered to be a background exposure level).
    Hexythiazox is not registered for any use patterns that would
result in intermediate-term residential exposure. Therefore, the
intermediate-term aggregate risk is the sum of the risk from exposure
to hexythiazox through food and water, which has already been
addressed, and will not be greater than the chronic aggregate risk.
    5. Aggregate cancer risk for U.S. population. Using the exposure
assumptions described in this unit for chronic exposure, EPA has
estimated increased cancer risk from exposure to hexythiazox at 2 in 1
million (2 x 10\-\6). Based on a critical commodity
analysis, the major contributors to the cancer risk were water (38% of
total exposure), strawberry (20% of total exposure), and field corn
syrup (16% of total exposure).
     Under the reasonable certainty of no harm standard in FFDCA
section 408(b)(2)(A)(ii), cancer risks must be no greater than
negligible. EPA interprets negligible cancer risks to be risks within
the range of an increased cancer risk of 1 in 1 million. Risks as high
as 3 in 1 million have been considered to be within this risk range.
EPA concludes that the estimated cancer risk for hexythiazox is within
the negligible risk range. The Agency notes that hexythiazox has been
classified as a possible human carcinogen based on increased incidence
of liver tumors in female mice. No chemical-related oncogenic effects
were reported in male mice or in male and female rats, and hexythiazox
has been classified as nonmutagenic.
    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

[[Page 30503]]

population or to infants and children from aggregate exposure to
hexythiazox residues.

IV. Other Considerations

A. Analytical Enforcement Methodology

    Adequate enforcement methodology (Method AMR-985-87,) 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 are no currently established CODEX, Canadian, or Mexican MRLs
for residues of hexythiazox in/on the subject commodities.

C. Response to Comments

    There was one comment received on the notice of filing. The
commenter, B. Sachua, requested that a zero tolerance be set for
hexythiazox based on the commenter's generalized criticisms of EPA's
risk assessment process. EPA has responded to B. Sachua's generalized
comments for hexythiazox and other chemicals on several occasions. (See
the Federal Register of March 22, 2006 (71 FR 14409) (FRL-7768-3); and
the Federal Register January 7, 2005 (70 FR 1349) (FRL-7691-4).

D. Revisions to Petitioned-For Tolerances

    EPA revised the proposed tolerance levels (from 0.05 to 0.02 ppm
for corn, field, grain; 2.0 to 2.5 ppm for corn, field, stover; and 2.0
to 6.5 ppm for corn, field, forage) based on the field trial data and
the maximum residue limit (MRL) tolerance calculator.

V. Conclusion

    Therefore, tolerances are established for combined residues of
hexythiazox, trans-5-(4-chlorophenyl)-N-cyclohexyl-4-methyl-2-
oxothiazolidine-3-carboxamide and its metabolites containing the (4-
chlorophenyl)-4-methyl-2-oxo-3-thiazolidine moiety (expressed as
parent), in or on corn, field, grain at 0.02 ppm; corn, field, stover
at 2.5 ppm; and corn, field, forage at 6.0 ppm.

VI. Statutory and Executive Order Reviews

    This final rule establishes tolerances 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 final rule has been
exempted from review under Executive Order 12866, this final 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 (59 FR 22951,
November 9, 2000) do not apply to this final rule. In addition,
this final 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: May 16, 2008.
Daniel J. Rosenblatt,
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), 346a and 371.

• 2. Section 180.448 is amended by alphabetically adding the following
commodities to the table in paragraph (c) to read as follows:

Sec.  180.448  Hexythiazox, tolerances for residues.

* * * * *
    (c) * * *

------------------------------------------------------------------------
                      Commodity                        Parts per million
------------------------------------------------------------------------
Corn, field, grain...................................               0.02
Corn, field, stover..................................                2.5
Corn, field, forage..................................                6.0
                                * * * * *
------------------------------------------------------------------------

* * * * *

[FR Doc. E8-11892 Filed 5-27-08; 8:45 am]
BILLING CODE 6560-50-S

 
 


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