FR Doc E5-8037

[Federal Register: December 30, 2005 (Volume 70, Number 250)]
[Proposed Rules]
[Page 77363-77371]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr30de05-22]

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 180

[EPA-HQ-OPP-2005-0518; FRL-7752-1]

Hexythiazox; Proposed Pesticide Tolerance

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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SUMMARY: This document proposes to establish tolerances 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-

[[Page 77364]]

thiazolidine moiety (expressed as parent) in or on grape; citrus fruit,
crop group 10 (CA, AZ, TX only); citrus, oil; citrus, dried pulp;
fruit, pome, group 11; apple, wet pomace; and cattle, sheep, goat, and
horse meat byproducts under the Federal Food, Drug, and Cosmetic Act
(FFDCA), as amended by the Food Quality Protection Act of 1996 (FQPA).

DATES: Comments must be received on or before January 30, 2006.

ADDRESSES: Submit your comments, identified by docket identification
(ID) number EPA-HQ-OPP-2005-0518, by one of the following methods:
Federal eRulemaking Portal http://www.regulations.gov/.

Follow the on-line instructions for submitting comments.
Agency Website: EDOCKET, EPA's electronic public docket
and comment system was replaced on November 25, 2005, by an enhanced
Federal-wide electronic docket management and comment system located at
http://www.regulations.gov/. Follow the on-line instructions.

E-mail: Comments may be sent by e-mail to
opp-docket@epa.gov, Attention: Docket ID number EPA-HQ-OPP-2005-0518.

Mail: Public Information and Records Integrity Branch
(PIRIB) (7502C), Office of Pesticide Programs (OPP), Environmental
Protection Agency, 1200 Pennsylvania Ave., NW., Washington, DC 20460-
0001, Attention: Docket ID number EPA-HQ-OPP-2005-0518.
Hand delivery: Public Information and Records Integrity
Branch (PIRIB), Office of Pesticide Programs (OPP), Environmental
Protection Agency, Rm. 119, Crystal Mall 2, 1801 S. Bell St.,
Arlington, VA, Attention: Docket ID number EPA-HQ-OPP-2005-0518. Such
deliveries are only accepted during the Docket's normal hours of
operation, and special arrangements should be made for deliveries of
boxed information.
Instructions: Direct your comments to docket ID number EPA-HQ-OPP-
2005-0518. EPA's policy is that all comments received will be included
in the public docket without change and may be made available online at
http://www.epa.gov/docket, including any personal information provided,

unless the comment includes information claimed to be Confidential
Business Information (CBI) or other information whose disclosure is
restricted by statute. Do not submit information that you consider to
be CBI or otherwise protected through EDOCKET, regulations.gov, or e-
mail. The EPA EDOCKET and the regulations.gov websites are ``anonymous
access'' system, which means EPA will not know your identity or contact
information unless you provide it in the body of your comment. If you
send an e-mail comment directly to EPA without going through the
EDOCKET and or regulations.gov; your e-mail address will be
automatically captured and included as part of the comment that is
placed in the public docket and made available on the Internet. If you
submit an electronic comment, EPA recommends that you include your name
and other contact information in the body of your comment and with any
disk or CD ROM you submit. If EPA cannot read your comment due to
technical difficulties and cannot contact you for clarification, EPA
may not be able to consider your comment. Electronic files should avoid
the use of special characters, any form of encryption, and be free of
any defects or viruses. For additional information about EPA's public
docket visit EDOCKET on line or see the Federal Register of May 31,
2002 (67 FR 38102) (FRL-7181-7).
Docket: All documents in the docket are listed in the
http://www.regulations.gov index. Although listed in the index, some

information is not publicly available, i.e., CBI or other information
whose disclosure is restricted by statute. Certain other material, such
as copyrighted material, will be publicly available only in hard copy
form. Publicly available docket materials are available either
electronically in http://www.regulations.gov or in hard copy at the Public

Information and Records Integrity Branch (PIRIB), Rm. 119, Crystal Mall
2, 1801 S. Bell St., Arlington, VA. This Docket Facility is
open from 8:30 a.m. to 4 p.m., Monday through Friday, excluding legal
holidays. The Docket telephone number is (703) 305-5805.

FOR FURTHER INFORMATION CONTACT: Olga Odiott, Registration Division
(7505C), 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:
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 provides
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 and Other
Related Information?

In addition to using EDOCKET (http://www.epa.gov/edocket/), you may

access this Federal Register document electronically through the EPA
Internet under the ``Federal Register'' listings at http://www.epa.gov/fedrgstr/.
A frequently updated electronic version of 40 CFR part 180

is available on E-CFR Beta Site Two at http://www.gpoaccess.gov/ecfr/.

C. What Should I Consider as I Prepare My Comments for EPA?

1. Submitting CBI. Do not submit this information to EPA through
http://www.regulations.gov, or e-mail. Clearly mark the part or all of the

information that you claim to be CBI. For CBI information in a disk or
CD ROM that you mail to EPA, mark the outside of the disk or CD ROM as
CBI and then identify electronically within the disk or CD ROM the
specific information that is claimed as CBI). In addition to one
complete version of the comment that includes information claimed as
CBI, a copy of the comment that does not contain the information
claimed as CBI must be submitted for inclusion in the public docket.
Information so marked will not be disclosed except in accordance with
procedures set forth in 40 CFR part 2.
2. Tips for preparing your comments. When submitting comments,
remember to:
i. Identify the rulemaking by docket ID number and other
identifying information (subject heading, Federal Register date, and
page number).
ii. Follow directions. The Agency may ask you to respond to
specific questions or organize comments by referencing a

[[Page 77365]]

Code of Federal Regulations (CFR) part or section number.
iii. Explain why you agree or disagree; suggest alternatives and
substitute language for your requested changes.
iv. Describe any assumptions and provide any technical information
and/or data that you used.
v. If you estimate potential costs or burdens, explain how you
arrived at your estimate in sufficient detail to allow for it to be
reproduced.
vi. Provide specific examples to illustrate your concerns, and
suggest alternatives.
vii. Explain your views as clearly as possible, avoiding the use of
profanity or personal threats.
viii. Make sure to submit your comments by the comment period
deadline identified.

II. Background and Statutory Findings

In the Federal Register of June 1, 2005 (70 FR 31455) (FRL-7711-8),
EPA issued a notice under section 408(d)(3) of FFDCA, 21 U.S.C.
346a(d)(3), announcing the filing of a pesticide petition (PP 3F6569)
by Gowan Company, 370 S. Main St., Yuma, AZ 85365. The petition
requested that 40 CFR 180.448 be amended by establishing a tolerance
for combined residues of the insecticide hexythiazox and its
metabolites containing the (4-chlorophenyl)-4-methyl-2-oxo-3-
thiazolidine moiety (expressed as parent), in or on grapes at 1.0 part
per million (ppm), raisins at 4.0 ppm, citrus at 0.5 ppm, and citrus
oil at 2.0 ppm. This notice included a summary of the petition prepared
by Gowan Company, the registrant. There were no comments received in
response to the notice of filing.
EPA is issuing this action as a proposed rule (rather than a final
rule) because after review of the initial petition and the Notice of
Filing the Agency has determined that:
The existing tolerance for apple, wet pomace must be
revised to 2.5 ppm.
The existing tolerances for cattle, goat, sheep, and horse
meat byproducts must be revised to 0.12 ppm.
EPA has also determined that:
The existing tolerances for apple and pear can be deleted
since a tolerance is being proposed for the entire pome fruit group.
The proposed tolerances for grapes at 1.0 ppm; citrus
fruit, crop group 10 at 0.5 ppm; and citrus oil at 2.0 ppm should be
revised to 0.75 ppm, 0.35 ppm, and 0.90 ppm, respectively.
Tolerances for citrus, dried pulp at 1.5 ppm; and fruit,
pome, group 11 at 1.7 ppm are necessary.
The proposed tolerance for raisins is not necessary.
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. * *
*''
EPA performs a number of analyses to determine the risks from
aggregate exposure to pesticide residues. For further discussion of the
regulatory requirements of section 408 of FFDCA and a complete
description of the risk assessment process, see the final rule on
Bifenthrin Pesticide Tolerances of November 26, 1997 (62 FR 62961)
(FRL-5754-7).

III. Aggregate Risk Assessment and Determination of Safety

Consistent with 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, consistent with section
408(b)(2) of FFDCA, for a tolerance for combined residues of
hexythiazox on grape at 0.75 ppm; citrus fruit, crop group 10 (CA, AZ,
TX only) at 0.35 ppm; citrus, oil at 0.90 ppm; citrus, dried pulp at
1.5 ppm; fruit, pome, group 11 at 1.7 ppm; apple, wet pomace at 2.5
ppm; and cattle, sheep, goat, and horse meat byproducts at 0.12 ppm.
EPA's assessment of exposures and risks associated with establishing
the tolerance follows:

A. Toxicological Profile

EPA has evaluated the available toxicity data and considered its
validity, completeness, and reliability as well as the relationship of
the results of the studies to human risk. EPA has also considered
available information concerning the variability of the sensitivities
of major identifiable subgroups of consumers, including infants and
children. The nature of the toxic effects caused by hexythiazox as well
as the no-observed-adverse-effect-level (NOAEL) and the lowest-
observed-adverse-effect-level (LOAEL) from the toxicity studies
reviewed are discussed in the Federal Register of April 18, 2001 (66 FR
19879) (FRL-6778-8). Since that time a micronucleus assay study has
been submitted and reviewed. Based on the submitted studies hexythiazox
has been classified as nonmutagenic.

B. Toxicological Endpoints

The dose at which the NOAEL from the toxicology study identified as
appropriate for use in risk assessment is used to estimate the
toxicological level of concern (LOC). However, the lowest dose at which
adverse effects of concern are identified is sometimes used for risk
assessment if no NOAEL was achieved in the toxicology study selected.
An uncertainty factor (UF) is applied to reflect uncertainties inherent
in the extrapolation from laboratory animal data to humans and in the
variations in sensitivity among members of the human population as well
as other unknowns. An UF of 100 is routinely used, 10X to account for
inter-species differences and 10X for intra-species differences.
For dietary risk assessment (other than cancer) the Agency uses the
UF to calculate an acute or chronic reference dose (aRfD or cRfD) where
the RfD is equal to the NOAEL divided by the appropriate UF (RfD =
NOAEL/UF). Where an additional safety factor is retained due to
concerns unique to the FQPA, this additional factor is applied to the
RfD by dividing the RfD by such additional factor. The acute or chronic
Population Adjusted Dose (aPAD or cPAD) is a modification of the RfD to
accommodate this type of FQPA Safety Factor (SF).
For non-dietary risk assessments (other than cancer) the UF is used
to determine the LOC. For example, when 100 is the appropriate UF (10X
to account for inter-species differences and 10X for intra-species
differences) the LOC is 100. To estimate risk, a ratio of the NOAEL to
exposures (margin of exposure (MOE) = NOAEL/exposure) is calculated and
compared to the LOC.
The linear default risk methodology (Q*) is the primary method
currently used by the Agency to quantify carcinogenic risk. The Q*
approach assumes that any amount of exposure will lead to some degree
of cancer risk. A Q* is calculated and used to estimate risk which
represents a probability of occurrence of additional cancer cases
(e.g., risk is expressed as 1 x 10⁶ or one in a million).
Under certain specific circumstances, MOE calculations will

[[Page 77366]]

be used for the carcinogenic risk assessment. In this non-linear
approach, a ``point of departure'' is identified below which
carcinogenic effects are not expected. The point of departure is
typically a NOAEL based on an endpoint related to cancer effects though
it may be a different value derived from the dose response curve. To
estimate risk, a ratio of the point of departure to exposure
(MOEcancer = point of departure/exposures) is calculated. A
summary of the toxicological endpoints for hexythiazox used for human
risk assessment is shown in Table 1 of this unit:

Table 1.--Summary of Toxicological Dose and Endpoints for Hexythiazox for Use in Human Risk Assessment
----------------------------------------------------------------------------------------------------------------
Dose Used in Risk FQPA SF and Endpoint Study and Toxicological
Exposure Scenario Assessment, UF for Risk Assessment Effects
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Acute dietary - females (13-50 years) NOAEL = 240 mg/kg/day FQPA SF = 1x Developmental Toxicity
of age UF = 100............... aPAD = 2.4 mg/kg/day... study - rat
aRfD = 2.4 mg/kg/day... Developmental LOAEL =
720 mg/kg/day based on
delayed ossification
----------------------------------------------------------------------------------------------------------------
Acute dietary (general population A dose and endpoint attributable to a single exposure were not identified
including infants and children) from the available oral toxicity studies, including maternal toxicity in
the developmental toxicity studies.
----------------------------------------------------------------------------------------------------------------
Chronic dietary (all populations) NOAEL= 2.5 mg/kg/day FQPA SF = 1x One-year toxicity
UF = 100............... cPAD = 0.025 mg/kg/day. feeding study - dog
cRfD = 0.025 mg/kg/day. LOAEL = 12.5 mg/kg/day
based on increased
absolute and relative
adrenal weights and
associated adrenal
histopathology
----------------------------------------------------------------------------------------------------------------
Cancer (oral, dermal, inhalation) Category C (possible Q1*= 2.22x10-\2\mg/kg/ Increases in incidence
human carcinogen) day-\1\ of malignant and
combined benign/
malignant liver tumors
in female mice
----------------------------------------------------------------------------------------------------------------
Short-term dermal (1-30 days) Oral maternal NOAEL = LOC for MOE = 100 Developmental toxicity
(occupational) 240 mg/kg/day (dermal (occupational) study - rat
absorption rate = 2%) LOAEL = 720 mg/kg/day
based on decreased
maternal body weight
gain during gestation
days 7-17 and
decreased food
consumption on
gestation days 9-12
----------------------------------------------------------------------------------------------------------------
Short-term inhalation (1-30 Oral maternal NOAEL= LOC for MOE = 100 Developmental toxicity
days)(occupational) 240 mg/kg/day (occupational) study - rat
(inhalation absorption LOAEL = 720 mg/kg/day
rate = 100%) based on decreased
maternal body weight
gain during gestation
days 7-17 and
decreased food
consumption on
gestation days 9-12
----------------------------------------------------------------------------------------------------------------

C. Exposure Assessment

1. Dietary exposure from food and feed uses. Tolerances have been
established (40 CFR 180.448) for the combined residues of hexythiazox,
in or on a variety of raw agricultural commodities ranging from 0.10-10
ppm. Tolerances have also been established for these same compounds in/
on milk (0.02 ppm), ruminant fat (0.02 ppm), and ruminant meat
byproducts (0.02 ppm) as a result of secondary residues. Risk
assessments were conducted by EPA to assess dietary exposures from
hexythiazox in food as follows:
i. Acute exposure. Acute dietary risk assessments are performed for
a food-use pesticide if a toxicological study has indicated the
possibility of an effect of concern occurring as a result of a 1-day or
single exposure. The Lifeline^TM (ver. 3.00) and Dietary
Exposure Evaluation Model - Food Consumption Intake Database (DEEM-
FCID^TM, ver. 2.03) models were used for the assessments.
Both of these models use food consumption data from the U. S.
Department of Agriculture (USDA's) 1994-1996, and 1998 Nationwide
Continuing Surveys of Food Intake by Individuals (CSFII) and
accumulated exposure to the chemical for each commodity. The following
assumptions were made for the acute exposure assessments: Tolerance
level residues, 100% crop treated, and DEEM^TM (ver 7.81)
default processing factors for all plant and livestock residues.
ii. Chronic exposure. In conducting this chronic dietary risk
assessment the Lifeline^TM (ver. 3.00), and DEEM-
FCID^TM, (ver. 2.03) models evaluated the individual food
consumption as reported by respondents in the USDA 1994-1996 and 1998
Nationwide Continuing Surveys of Food Intake by Individuals (CSFII) and
accumulated exposure to the chemical for each commodity. The following
assumptions were made for the chronic exposure assessments: Average
percent crop treated (PCT) estimates for several registered
commodities, projected PCT estimates for proposed commodities, average
field trial residues, FDA monitoring data for stone fruit (excluding
cherry) and pome fruit,

[[Page 77367]]

experimentally determined processing factors when available, and
anticipated livestock residues (dietary burden calculated using average
field trial and PCT estimates).
iii. Cancer. The cancer dietary analyses were also conducted using
the Lifeline^TM (ver. 3.00), and DEEM-FCID^TM,
(ver. 2.03) models. The cancer dietary analyses assumed the same plant
and livestock residues as that of the chronic analyses.
iv. Anticipated residue and percent crop treated (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 chemicals that have been
measured in food. If EPA relies on such information, EPA must pursuant
to section 408(f)(1) require 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. Following
the initial data submission, EPA is authorized to require similar data
on a time frame it deems appropriate. For the present action, EPA will
issue such Data Call-Ins for information relating to anticipated
residues as are required by FFDCA section 408(b)(2)(E) and authorized
under FFDCA section 408(f)(1). Such Data Call-Ins will be required to
be submitted no later than 5 years from the date of issuance of this
tolerance.
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 the Agency can make the following findings: Condition 1,
that 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 such
pesticide residue; Condition 2, that the exposure estimate does not
underestimate exposure for any significant subpopulation group; and
Condition 3, if 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 section 408(b)(2)(F) of FFDCA, EPA may require registrants to submit
data on PCT.
The Agency used PCT information as follows. Average values for PCT
data were used in the chronic and cancer analyses for the following
commodities with established tolerances: < 1% for almonds, apples,
apricots, cherries, prunes, plums, and walnuts; 5% for nectarines,
peaches, and pears; 10% for dates; and 20% for strawberries. Projected
average PCT values were used for proposed commodities as follows: 23%
for grapes and 21% for oranges.
The Agency believes that the three conditions previously discussed
have been met. With respect to Condition 1, PCT estimates are derived
from available federal, state, and private market survey data. For
existing crop sites on pesticide registrations (``existing use''), EPA
uses an average PCT for chronic dietary exposure estimates. The average
PCT figure is derived by combining available federal, state, and
private market survey data on the existing use, averaging by year,
averaging across all years, and rounding up to the nearest multiple of
five except for those situations in which the average PCT is less than
one. In those cases < 1% is used as the average and < 2.5% is used as the
maximum. EPA uses a maximum PCT for acute dietary exposure estimates.
The maximum PCT figure is the single maximum value reported overall
from available federal, state, and private market survey data on the
existing use, across all years, and rounded up to the nearest multiple
of five. In most cases, EPA uses available data from USDA/National
Agricultural Statistics Service (NASS), Proprietary Market Surveys, and
the National Center for Food and Agriculture Policy (NCFAP) for the
most recent six years. The Agency is reasonably certain that the
percentage of the food treated is not likely to be an underestimation.
The Agency projects PCT for a new pesticide use by assuming that
the PCT for the pesticide's initial five years will not exceed the
average PCT of the dominant pesticide (the one with the largest PCT)
within its chemical type over three latest available years. For grapes
hexythiazox was compared with imidacloprid. For oranges, hexythiazox
was compared with abamectin and S-methoprene. 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 non-proprietary and directly available without
computation. This method of projecting PCT for a new pesticide, with or
without regard to specific pest(s), produces an upper-end projection
that is unlikely, in most cases, to be exceeded in actuality because
the dominant pesticide is well-established and accepted by farmers.
Factors that bear on whether a projection based on the dominant
pesticide could be exceeded are whether the new pesticide is more
efficacious or controls a broader spectrum of pests than the dominant
pesticide within its similar type, whether it is more cost-effective
than the dominant pesticide, and whether it is likely to be readily
accepted by growers and experts.
As to Conditions 2 and Condition 3, 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 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 lacks
sufficient monitoring exposure data to complete a comprehensive dietary
exposure analysis and risk assessment for hexythiazox in drinking
water. Because the Agency does not have comprehensive monitoring data,
drinking water concentration estimates are made by reliance on
simulation or modeling taking into account data on the physical
characteristics of hexythiazox.
The Agency uses the Generic Estimated Environmental Concentration
(GENEEC) or the Pesticide Root Zone/Exposure Analysis Modeling System
(PRZM/EXAMS) to estimate pesticide concentrations in surface water and
(SCI-GROW), which predicts pesticide concentrations in ground water. In
general, EPA will use GENEEC (a Tier 1 model) before using PRZM/EXAMS
(a Tier 2 model) for a screening-level assessment for surface water.
The GENEEC model is a subset of the PRZM/EXAMS model that uses a
specific high-end runoff scenario for pesticides. GENEEC incorporates a
farm pond scenario, while PRZM/EXAMS incorporate an index reservoir
environment in place of the previous pond scenario. The PRZM/EXAMS
model includes a percent crop area factor as an adjustment to account
for the maximum percent crop coverage within a watershed or drainage
basin.

[[Page 77368]]

None of these models include consideration of the impact processing
(mixing, dilution, or treatment) of raw water for distribution as
drinking water would likely have on the removal of pesticides from the
source water. The primary use of these models by the Agency at this
stage is to provide a coarse screen for sorting out pesticides for
which it is highly unlikely that drinking water concentrations would
ever exceed human health levels of concern.
The acute, chronic, and cancer analyses incorporated modeled
surface water and/or ground water estimates generated using PRZM/EXAMS
and SCI-GROW, respectively. The SCI-GROW model evaluated the highest
registered/proposed application rate. The PRZM/EXAMS model evaluated
all registered/proposed application scenarios. The PRZM/EXAMS
evaluation considered potential spatial variation by using model
scenarios which represent a combination of specific agronomic, soil,
and climatological parameters which are geographically specific.
Based on the PRZM/EXAMS and SCI-GROW models the estimated drinking
water concentrations (EDWCs) of hexythiazox for acute exposures are
estimated to be 4.23 parts per billion (ppb) for surface water and
0.00503 ppb for ground water. The EDWCs for chronic exposures are
estimated to be 2.26 ppb for surface water and 0.00503 ppb for ground
water. The EDWCs for cancer are estimated to be 1.72 ppb for surface
water and 0.00503 ppb for ground water.
3. From non-dietary exposure. The term ``residential exposure'' is
used in this document to refer to non-occupational, non-dietary
exposure (e.g., for lawn and garden pest control, indoor pest control,
termiticides, and flea and tick control on pets).
Hexythiazox 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 the 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.''
Unlike other pesticides for which EPA has followed a cumulative
risk approach based on a common mechanism of toxicity, EPA has not made
a common mechanism of toxicity finding as to hexythiazox and 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 not assumed that hexythiazox has a
common mechanism of toxicity with other substances. For information
regarding EPA's efforts to determine which chemicals have a common
mechanism of toxicity and to evaluate the cumulative effects of such
chemicals, see the policy statements released by EPA's Office of
Pesticide Programs concerning common mechanism determinations and
procedures for cumulating effects from substances found to have a
common mechanism on 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 tenfold margin of safety for infants and children in the
case of threshold effects to account for prenatal and postnatal
toxicity and the completeness of the data base on toxicity and exposure
unless EPA determines that a different margin of safety will be safe
for infants and children. Margins of safety are incorporated into EPA
risk assessments either directly through use of a MOE analysis or
through using uncertainty (safety) factors in calculating a dose level
that poses no appreciable risk to humans.
2. Prenatal and postnatal sensitivity. 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 determined that the special FQPA SF to protect
infants and children should be removed. The recommendation is based on
the following:
The toxicology data base for hexythiazox is considered
complete 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.
Exposure data are complete or are estimated based on data
that reasonably accounts for potential exposures.
There is no evidence of increased susceptibility of rats
or rabbits to in utero and/or postnatal exposure to hexythiazox.

E. Aggregate Risks and Determination of Safety

Acute, chronic, and cancer modeled drinking water estimates were
incorporated directly into the aggregate dietary analysis, rather than
using back-calculated drinking water levels of comparison (DWLOCs). EPA
is no longer comparing EDWCs generated by water quality models with
DWLOCs. Instead, EPA is now directly incorporating the actual water
quality model output concentrations into the risk assessment. This
method of incorporating water concentrations into our aggregate
assessments relies on actual CSFII-reported drinking water consumption
and more appropriately reflects the full distribution of drinking water
concentrations.
The acute analysis assumed the PRZM/EXAMS 1 in 10-year annual peak
drinking water concentration. The chronic analysis assumed the PRZM/
EXAMS 1 in 10-year annual mean concentration. These estimates were
higher than the SCI-GROW estimates.
The DEEM-FCID^TM cancer analysis assumed the PRZM/EXAMS
30-year annual mean concentration (which was higher than the SCI-GROW
estimate). Since Lifeline^TM allows for the assignment of
different drinking water concentrations for those individuals in
households with private wells, the Lifeline^TM analysis
incorporated both the PRZM/EXAMS 30-year annual mean concentration and
the SCI-GROW concentration. The Lifeline^TM analysis assumed
the SCI-GROW concentration for individuals obtaining drinking water
from individual wells and the PRZM/EXAMS 30-year annual mean
concentration for individuals in households receiving drinking water
from public water systems and other sources.
1. Acute risk. Using the exposure assumptions discussed in this
unit for acute exposure, the resulting Lifeline^TM and DEEM-
FCID^TM exposure estimates were <1% of the aPAD for females
13-49 years old. An acute endpoint for the remaining population
subgroups was not identified. EPA does not expect the aggregate
exposure to exceed 100% of the aPAD, as shown in Table 2 of this unit:

[[Page 77369]]

Table 2.--Aggregate Risk Assessment for Acute Exposure to Hexythiazox (Food + Drinking Water)
--------------------------------------------------------------------------------------------------------------------------------------------------------
%aPAD Exposure (mg/kg/day)
Population Subgroup aPAD (mg/kg/day) ---------------------------------------------------------------------------
DEEM-FCID Lifeline DEEM-FCID Lifeline
--------------------------------------------------------------------------------------------------------------------------------------------------------
Females (13-49 years old) 2.4 < 1 < 1 0.010176 0.0120
--------------------------------------------------------------------------------------------------------------------------------------------------------

2. Chronic risk. Using the exposure assumptions described in this
unit for chronic exposure, the resulting Lifeline^TM and
DEEM-FCID^TM exposure estimates were <1% of the cPAD for the
U.S. population, < 1% of the cPAD for all infants and 1% of the cPAD for
children 1-2 years old, the children subpopulation at greatest
exposure]. There are no residential uses for hexythiazox that result in
chronic residential exposure to hexythiazox. EPA does not expect the
aggregate exposure to exceed 100% of the cPAD, as shown in Table 3 of
this unit:

Table 3.--Aggregate Risk Assessment for Chronic (Non-Cancer) Exposure to Hexythiazox (Food + Drinking Water)
--------------------------------------------------------------------------------------------------------------------------------------------------------
%cPAD Exposure (mg/kg/day)
Population Subgroup cPAD (mg/kg/day) ---------------------------------------------------------------------------
DEEM-FCID Lifeline DEEM-FCID Lifeline
--------------------------------------------------------------------------------------------------------------------------------------------------------
General U.S. population 0.025 < 1 < 1 0.000110 0.000094
--------------------------------------------------------------------------------------------------------------------------------------------------------
All Infants < (1 year old) 0.025 < 1 < 1 0.000217 0.000185
--------------------------------------------------------------------------------------------------------------------------------------------------------
Children (1-2 years old) 0.025 1 1 0.000267 0.000251
--------------------------------------------------------------------------------------------------------------------------------------------------------

3. Aggregate cancer risk for U.S. population. Based on the exposure
assumptions described in this unit the resulting cancer DEEM-
FCID^TM and Lifeline^TM dietary exposure estimates
for the U.S. population yielded a cancer risk of 2.30 in 1 million and
2.03 in 1 million, respectively. DEEM-FCID^TM resulted in a
higher cancer risk estimate due to differing drinking water assumptions
described in this unit (Lifeline^TM permits incorporation of
the entire PRZM-EXAMS distribution when conducting a cancer analysis
while DEEM-FCID^TM permits only a point estimate). Based on a
the DEEM-FCID^TM analysis, the major contributors to the
cancer risk were water (35% of total exposure), strawberry (15% of
total exposure), grape (14% of total exposure), field corn (13% of
total exposure), citrus (9% of total exposure), caneberry (5% of total
exposure), and hop (5% of total exposure). The remaining commodities
combined for 4% of the 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
has consistently interpreted 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. A summary of the cancer dietary
exposure estimates for hexythiazox are shown in Table 4 of this unit:

Table 4.--Aggregate Cancer Dietary Exposure and Risk for Hexythiazox (Food + Drinking Water)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Exposure (mg/kg/day) Risk
Population Subgroup Q1*1 ---------------------------------------------------------------------------
DEEM-FCID Lifeline DEEM-FCID Lifeline
--------------------------------------------------------------------------------------------------------------------------------------------------------
General U.S. population 0.022 0.000104 0.00091 2.30 x 10-6 2.03 x 10-6
--------------------------------------------------------------------------------------------------------------------------------------------------------

4. Determination of safety. Based on these risk assessments, EPA
concludes that there is a reasonable certainty that no harm will result
to the general population, and to infants and children from aggregate
exposure to hexythiazox residues.

IV. Other Considerations

A. Analytical Enforcement Methodology

The Pesticide Analytical Manual Volume II (PAM II) of the Food and
Drug Administration (FDA) includes suitable analytical methods for the
determination of hexythiazox and metabolites containing the (4-
chlorophenyl)-4-methyl-2-oxo-3-thiazolidine moiety (AMR-985-87) in pome
fruit, grape, and citrus, livestock tissue, and milk.

B. International Residue Limits

The Codex and EPA tolerance expression differ; therefore,
harmonization is not possible

C. Conditions

As a condition of registration the registrant must submit the
following data:
Apple and pear field trial data for the emulsifiable
concentrate (EC) formulation. The recommended tolerance may
overestimate actual expected residues following application of
hexythiazox as labeled since is based on an exaggerated rate from the
wettable powder residue trial and the maximum factor by which the EC
formulation

[[Page 77370]]

exceeded the WP formulation in the apple side-by-side field trials.
An orange processing study.

V. Conclusion

Tolerances are proposed 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 grape at
0.75 ppm; citrus fruit, crop group 10 (CA, AZ, TX only) at 0.35 ppm;
citrus, oil at 0.90 ppm; citrus, dried pulp at 1.5 ppm; fruit, pome,
group 11 at 1.7 ppm; apple, wet pomace at 2.5 ppm; and cattle, sheep,
goat, and horse meat byproducts at 0.12 ppm.

VI. Statutory and Executive Order Reviews

This proposed 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 proposed rule has
been exempted from review under Executive Order 12866 due to its lack
of significance, this proposed rule is not subject to Executive Order
13211, Actions Concerning Regulations That Significantly Affect Energy
Supply, Distribution, or Use (66 FR 28355, May 22, 2001). This proposed
rule does not contain any information collections subject to OMB
approval under the Paperwork Reduction Act (PRA), 44 U.S.C. 3501 et
seq., or impose any enforceable duty or contain any unfunded mandate as
described under Title II of the Unfunded Mandates Reform Act of 1995
(UMRA) (Public Law 104-4). Nor does it require any special
considerations under Executive Order 12898, entitled Federal Actions to
Address Environmental Justice in Minority Populations and Low-Income
Populations (59 FR 7629, February 16, 1994); or OMB review or any
Agency action under Executive Order 13045, entitled Protection of
Children from Environmental Health Risks and Safety Risks (62 FR 19885,
April 23, 1997). This action does not involve any technical standards
that would require Agency consideration of voluntary consensus
standards pursuant to section 12(d) of the National Technology Transfer
and Advancement Act of 1995 (NTTAA), Public Law 104-113, section 12(d)
(15 U.S.C. 272 note). Pursuant to the Regulatory Flexibility Act (RFA)
(5 U.S.C. 601 et seq.), the Agency hereby certifies that this proposed
action will not have significant negative economic impact on a
substantial number of small entities. Establishing a tolerance, in
effect, removes the statutory bar on the use of a pesticide on the
specified crops and thus has no negative economic impact. In addition,
the Agency has determined that this action will not have a substantial
direct effect on States, on the relationship between the national
government and the States, or on the distribution of power and
responsibilities among the various levels of government, as specified
in Executive Order 13132, entitled Federalism (64 FR 43255, August 10,
1999). Executive Order 13132 requires EPA to develop an accountable
process to ensure ``meaningful and timely input by State and local
officials in the development of regulatory policies that have
federalism implications.'' ``Policies that have federalism
implications'' is defined in the Executive Order to include regulations
that have ``substantial direct effects on the States, on the
relationship between the national government and the States, or on the
distribution of power and responsibilities among the various levels of
government.'' This proposed rule directly regulates growers, food
processors, food handlers and food retailers, not States. This action
does not alter the relationships or distribution of power and
responsibilities established by Congress in the preemption provisions
of section 408(n)(4) of FFDCA. For these same reasons, the Agency has
determined that this proposed rule does not have any ``tribal
implications'' as described in Executive Order 13175, entitled
Consultation and Coordination with Indian Tribal Governments (65 FR
67249, November 6, 2000). Executive Order 13175, requires EPA to
develop an accountable process to ensure ``meaningful and timely input
by tribal officials in the development of regulatory policies that have
tribal implications.'' ``Policies that have tribal implications'' is
defined in the Executive Order to include regulations that have
``substantial direct effects on one or more Indian tribes, on the
relationship between the Federal Government and the Indian tribes, or
on the distribution of power and responsibilities between the Federal
Government and Indian tribes.'' This proposed rule will not have
substantial direct effects on tribal governments, on the relationship
between the Federal Government and Indian tribes, or on the
distribution of power and responsibilities between the Federal
Government and Indian tribes, as specified in Executive Order 13175.
Thus, Executive Order 13175 does not apply to this proposed rule.

List of Subjects in 40 CFR Part 180

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

Dated: December 22, 2005.
Lois Rossi,
Director, Registration Division, Office of Pesticide Programs.
Therefore, it is proposed that 40 CFR chapter I be 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 removing the commodities ``apple''
and ``pear'' and alphabetically adding new commodities to the table in
paragraphs (a) and (c) to read as follows:

Sec. 180.448 Hexythiazox; tolerances for residues.

(a) * * *

------------------------------------------------------------------------
Commodity Parts per million
------------------------------------------------------------------------
* * * * *
Citrus, dried pulp................................... 1.5
Citrus, oil.......................................... 0.90
* * * * *
Fruit, pome, group 11................................ 1.7
* * * * *
Grape................................................ 0.75
* * * * *
------------------------------------------------------------------------

* * * * *
(c) * * *

------------------------------------------------------------------------
Commodity Parts per million
------------------------------------------------------------------------
* * * * *
Fruit, citrus group 10 (CA, AZ, TX only)............. 0.35
------------------------------------------------------------------------

* * * * *
3. Section 180.448 is amended by revising the following commodities
in the table in paragraph (a) to read as follows:

Sec. 180.448 Hexythiazox; tolerances for residues.

(a) * * *

[[Page 77371]]

* * * * *
Cattle, meat byproducts.............................. 0.12
* * * * *
Goat, meat byproducts................................ 0.12
* * * * *
Horse, meat byproducts............................... 0.12
* * * * *
Sheep, meat byproducts............................... 0.12
------------------------------------------------------------------------

* * * * *
[FR Doc. E5-8037 Filed 12-29-05; 8:45 am]

BILLING CODE 6560-50-S