Document ID: EPA-HQ-OPP-2005-0309-0004
Agency: epa
Document Type: Rule
Title: Hexythiazox; Pesticide Tolerances
Posted Date: 2008-05-28T04:00Z

[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 (65 FR 
67249, 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.

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.

0
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