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Thiencarbazone-methyl; Pesticide Tolerances

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[Federal Register: October 15, 2008 (Volume 73, Number 200)]
[Rules and Regulations]
[Page 60963-60969]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr15oc08-20]

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ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 180
[EPA-HQ-OPP-2008-0132; FRL-8382-7]

Thiencarbazone-methyl; Pesticide Tolerances

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

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SUMMARY: This regulation establishes tolerances for residues of
thiencarbazone-methyl [methyl 4-[[[(4,5-dihydro-3-methoxy-4-methyl-5-
oxo-1H-1,2,4-triazol-1-yl)-carbonyl]amino]sulfonyl]-5-methyl-3-
thiophenecarboxylate], per se, in or on field corn, pop corn, sweet
corn, and wheat; combined residues of thiencarbazone-methyl and its
metabolite BYH 18636-MMT [5-methoxy-4-methyl-2,4-dihydro-3H-1,2,4-
triazol-3-one], calculated as the parent compound, in or on livestock
commodities; and indirect or inadvertent combined residues of
thiencarbazone-methyl and its metabolite BYH 18636-MMT-glucoside [2-
hexopyranosyl-5-methoxy-4-methyl-2,4-dihydro-3H-1,2,4-triazol-3-one],
calculated as the parent compound, in or on soybeans. Bayer CropScience
requested these tolerances under the Federal Food, Drug, and Cosmetic
Act (FFDCA).

DATES: This regulation is effective October 15, 2008. Objections and
requests for hearings must be received on or before December 15, 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-2008-0132. All documents in the
docket are listed in the docket index available at http://
www.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

[[Page 60964]]

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

FOR FURTHER INFORMATION CONTACT: Jim Tompkins, Registration Division
(7505P), Office of Pesticide Programs, Environmental Protection Agency,
1200 Pennsylvania Ave., NW., Washington, DC 20460-0001; telephone
number: 703-305-5697; e-mail address: tompkins.jim@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 electronically available documents 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, 21 U.S.C. 346a, 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-2008-0132 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 December 15, 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-2008-0132, 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 Facility'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 April 16, 2008 (73 FR 20633) (FRL-8359-1), 
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
7F7208) by Bayer CropScience, 2 T.W. Alexander Drive, Research Triangle
Park, NC 27709. The petition proposed tolerances be established for
residues of the herbicide thiencarbazone-methyl, per se, in or corn,
field, grain at 0.01 parts per million (ppm); corn, sweet, kernels at
0.01 ppm; wheat, grain at 0.01 ppm; and soybean, seed at 0.01 ppm;
thiencarbazone-methyl and its metabolites BYH 18636-MMT-glucoside and
BYN 18636-N-desmethyl [methyl 4-(([(3-methoxy-5-oxo-4,5-dihydro-1H-
1,2,4-triazol-1-yl)carbonyl]amino)sulfonyl)-5-methylthiophene-3-
carboxylate], calculated as the parent compound, in or on corn, field,
forage at 0.03 ppm; corn, sweet, forage at 0.15 ppm; corn, field,
stover at 0.04 ppm; corn, sweet stover at 0.04 ppm; corn, sweet, kernel
plus cob with husks removed at 0.01 ppm; wheat, hay at 0.02 ppm; wheat,
straw at 0.02 ppm; wheat, forage at 0.09 ppm; soybean, forage at 0.04
ppm; soybean, hay at 0.15 ppm, and cotton gin by-products at 0.15 ppm;
and thiencarbazone-methyl and its metabolite BYH 18636-MMT, calculated
as the parent compound, in or on milk at 0.01 ppm; cattle, meat at 0.01
ppm; cattle, fat at 0.01 ppm; cattle, liver at 0.05 ppm; cattle, kidney
at 0.02 ppm; goat, meat at 0.01 ppm; goat, fat at 0.01 ppm; goat, liver
at 0.05 ppm; goat, kidney at 0.02 ppm; hog, meat at 0.01 ppm; hog, fat
at 0.01 ppm; hog, liver at 0.05 ppm; hog, kidney at 0.02 ppm; horse,
meat at 0.01 ppm; horse, liver at 0.05 ppm; horse, kidney at 0.02 ppm;
sheep, meat at 0.01 ppm; sheep, fat at 0.01 ppm; sheep, liver at 0.05
ppm; and sheep, kidney at 0.02 ppm. There were no comments received in
response to the notice of filing.
    Tolerance levels and commodity expressions have been revised for
corn, field, forage; corn, field, stover; corn, sweet, forage; corn,
sweet, stover; wheat, forage; wheat, hay; wheat, straw; cotton gin
byproducts; soybean, seed; and livestock commodities as a result of the
review of the actual residue data and so that the listed commodities
agree with current EPA commodity terms. Therefore, EPA is establishing
tolerances for residues of thiencarbazone-methyl, per se, in or on
corn, field, forage at 0.04 ppm; corn, field, grain at 0.01 ppm; corn,
field, stover at 0.02 ppm; corn, pop, grain at 0.01 ppm; corn, pop,
stover at 0.01 ppm; corn, sweet, forage at 0.05 ppm; corn, sweet,
kernel plus cob with husks removed at 0.01 ppm; corn, sweet, stover at
0.05 ppm; wheat, forage at 0.10 ppm; wheat, grain at 0.01 ppm; wheat,
hay at 0.01 ppm; and wheat, straw at 0.01 ppm; combined residues of
thiencarbazone-methyl and its metabolite BYH 18636-MMT, calculated as
the parent compound, in or on cattle, meat at 0.02 ppm; cattle, meat
byproducts at 0.02 ppm; goat, meat at

[[Page 60965]]

0.02 ppm; goat, meat byproducts at 0.02 ppm; horse, meat at 0.02 ppm;
horse, meat byproducts at 0.02 ppm; milk at 0.02 ppm; sheep, meat at
0.02 ppm; and sheep, meat byproducts at 0.02 ppm; and indirect or
inadvertent combined residues of thiencarbazone-methyl and its
metabolite BYH 18636-MMT-glucoside, calculated as the parent compound,
in or on soybean, forage at 0.04 ppm and soybean, hay at 0.15 ppm. The
reasons for these changes are explained in Unit IV.C.

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 residues of thiencarbazone-methyl, per se, in or on
corn, field, forage at 0.04 ppm; corn, field, grain at 0.01 ppm; corn,
field, stover at 0.02 ppm; corn, pop, grain at 0.01 ppm; corn, pop,
stover at 0.01 ppm; corn, sweet, forage at 0.05 ppm; corn, sweet,
kernel plus cob with husks removed at 0.01 ppm; corn, sweet, stover at
0.05 ppm; wheat, forage at 0.10 ppm; wheat, grain at 0.01 ppm; wheat,
hay at 0.01 ppm; and wheat, straw at 0.01 ppm; combined residues of
thiencarbazone-methyl and its metabolite BYH 18636-MMT, calculated as
the parent compound, in or on cattle, meat at 0.02 ppm; cattle, meat
byproducts at 0.02 ppm; goat, meat at 0.02 ppm; goat, meat byproducts
at 0.02 ppm; horse, meat at 0.02 ppm; horse, meat byproducts at 0.02
ppm; milk at 0.02 ppm; sheep, meat at 0.02 ppm; and sheep, meat
byproducts at 0.02 ppm; and indirect or inadvertent combined residues
of thiencarbazone-methyl and its metabolite BYH 18636-MMT-glucoside,
calculated as the parent compound, in or on soybean, forage at 0.04 ppm
and soybean, hay at 0.15 ppm. EPA's assessment of exposures and risks
associated with establishing tolerances 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.
    Thiencarbazone-methyl has low toxicity in acute toxicity and
irritation assessments and is not a skin sensitizer. In subchronic and
chronic oral toxicity studies, the critical target organ for
thiencarbazone-methyl is the urinary tract including the kidney,
bladder and ureters. Toxicity in these structures from the formation of
calculi that are formed by the deposition of the parent and are
associated with the sulfonamide structure and these are evident in the
dog, considered the most sensitive species at 179 milligrams/kilograms/
day (mg/kg/day) in the chronic study. In mice, at 599 mg/kg/day in
males and 758 mg/kg/day in females, doses where there was formation of
calculi in the urothelial system, thiencarbazone-methyl was associated
with transitional cell epithelium tumors in the urinary bladder in one
male and three females and in the prostatic urethra in one male. The
battery of mutagenicity/genetic toxicity studies did not indicate a
mutagenicity concern. Since the neoplasia occurred only in the high
dose group, thiencarbazone-methyl was classified as "Not likely to be
a carcinogen to humans at doses that do not cause urothelial cytotoxicity."
    Specific information on the studies received and the nature of the
adverse effects caused by thiencarbazone-methyl as well as the no-
observed-adverse-effect-level (NOAEL) and the lowest-observed-adverse-
effect-level (LOAEL) from the toxicity studies can be found at http://
www.regulations.gov in document Human Health Risk Assessment at pages
56-59 in docket ID number EPA-HQ-OPP-2008-0132.

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 NOAEL in the toxicology study
identified as appropriate for use in risk assessment. However, if a
NOAEL cannot be determined, 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-
term, intermediate-term, 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 thiencarbazone-methyl
used for human risk assessment can be found at http://
www.regulations.gov in document Human Health Risk Assessment at pages
25-26 in docket ID number EPA-HQ-OPP-2008-0132.

C. Exposure Assessment

    1. Dietary exposure from food and feed uses. In evaluating dietary
exposure to thiencarbazone-methyl, EPA considered exposure under the
petitioned-for tolerances. EPA assessed dietary exposures from in food
as follows:
    i. Acute exposure. Quantitative acute dietary exposure and risk
assessments are performed for a food-use pesticide,

[[Page 60966]]

if a toxicological study has indicated the possibility of an effect of
concern occurring as a result of a 1-day or single exposure.
    No such effects were identified in the toxicological studies for
thiencarbazone-methyl; therefore, a quantitative acute dietary exposure
assessment is unnecessary.
    ii. Chronic exposure. In conducting the chronic dietary exposure
assessment EPA used the dietary model Dietary Exposure Evaluation
Model-Food Commodity Intake Database (DEEM-FCID). The modeled exposure
estimates for the chronic assessment are based on tolerance level
residues, assuming 100% of the crops are treated, and include the
highest modeled estimated drinking water concentrations (EDWCs).
    iii. Cancer. Thiencarbazone-methyl is not likely to be carcinogenic
to humans at doses that do not cause urothelium cytotoxicity. The
chronic reference dose (cRfD) of 117 mg/kg/day is adequately protective
of any cancer or pre-cancerous effects seen in carcinogenicity studies
in rats and mice. The formation of the low incidence of the
transitional cell tumors of the bladder in both sexes and urethra/
prostrate in males that develop at 599 mg/kg/day in males and 758 mg/
kg/day in females in mice is considered to be related to secondary
effect of the urothelial toxicity (irritation) and regenerative
proliferation associated with the formation of urinary tract crystals/
calculi. This is commonly seen for bladder carcinogensis in rodents for
non-genotoxic chemicals of the sulfonamide class. No tumors were seen
in rats.
    iv. Anticipated residue and percent crop treated (PCT) information.
Tolerance level residues and 100 PCT were assumed for all food commodities.
    2. Dietary exposure from drinking water. The Agency used screening
level water exposure models in the dietary exposure analysis and risk
assessment for thiencarbazone-methyl in drinking water. These
simulation models take into account data on the physical, chemical, and
fate/transport characteristics of thiencarbazone-methyl. 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 First Index Reservoir Screening Tool (FIRST) and
Screening Concentration in Ground Water (SCI-GROW) models, the EDWCs of
thiencarbazone-methyl for chronic exposures are estimated to be 0.36
parts per billion (ppb) for surface water and 0.00079 ppb for ground
water.
    Modeled estimates of drinking water concentrations were directly
entered into the dietary exposure model.
    For chronic dietary risk assessment, the water concentration of
value 0.36 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).
    Thiencarbazone-methyl is currently pending registration for the
following uses that could result in residential exposures: Application
to residential turfgrass and recreational sites. EPA assessed
residential exposure using the following assumptions: Residential
handlers may receive short-term dermal and inhalation exposure when
mixing, loading, and applying the herbicide. Residential post-
application exposure via the inhalation route is expected to be
negligible; however, dermal exposure is likely for adults and children
entering treated lawns. Toddlers may also experience exposure via
incidental non-dietary ingestion during post-application activities on
treated turf. Residential short-term dermal, inhalation, and incidental
oral exposures were assessed using the same NOAEL (159 mg/kg/day). One
hundred percent absorption via the dermal and inhalation exposure
routes was assumed, resulting in very conservative estimates of risk (MOEs).
    4. Cumulative effects from substances with a common mechanism of
toxicity. Section 408(b)(2)(D)(v) of FFDCA requires that, when
considering whether to establish, modify, or revoke a tolerance, the
Agency consider ``available information'' concerning the cumulative
effects of a particular pesticide's residues and ``other substances
that have a common mechanism of toxicity.''
    Although thiencarbazone-methyl has in common with other sulfonamide
chemicals the ability to cause urinary tract calculi and in some cases
tumors in the urinary tract at high doses, EPA has not made a common
mechanism finding for thiencarbazone-methyl such that cumulative risk
assessment based on chemicals with a common mechanism is necessary for
thiencarbazone-methyl and other sulfonamides. With thiencarbazone-
methyl, the formation of calculi in the urinary tract results from the
precipitation of thiencarbazone-methyl once it reaches saturation in
the animal's system. Precipitation of thiencarbazon-methyl is a
physical/chemical process and not a mechanism of toxicity. Exposures to
thiencarbazone-methyl and other sulfonamides, are not additive with
regard to the formation of urinary tract calculi at anticipated
exposure levels. At higher doses, each sulfonamide will form calculi
independently of the other by a separate physical/chemical process. At
lower doses, near the anticipated exposure levels, calculi will not
form even if there is exposure to multiple sulfonamides because
sulfonamides will not influence the formation of precipitates by each
other. It would be appropriate to add exposures in assessing
precipitate formation only if the sulfonamides interacted somehow
during crystal formation. 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(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. There is no indication of
increased susceptibility of rat or rabbit offspring to thiencarbazone-
methyl as indicated by the rat and rabbit developmental toxicity
studies and the rat reproduction study. There is no concern for
increased susceptibility to offspring.
    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 thiencarbazone-methyl is complete,
except for immunotoxicity studies. EPA

[[Page 60967]]

began requiring functional immunotoxicity testing of all food and non-
food use pesticides on December 26, 2007. Since the requirement went
into effect well after this tolerance petition was submitted, these
studies are not yet available for thiencarbazone-methyl. In the absence
of specific immunotoxicity studies, EPA has evaluated the available
toxicity data for thiencarbazone-methyl and determined that an
additional database uncertainty factor is not needed to account for
potential immunotoxicity. EPA's determination is based on the following
considerations.
    a. EPA considered the entire toxicity database for thiencarbazone-
methyl for adverse effects on the thymus and spleen for possible
indications of immunotoxicity and determined that there were no changes
in these structures indicative of immunotoxicity. There were also no
changes in leucocytes or differential leucocyte counts to suggest an
effect on the immune system.
    b. Thiencarbazone-methyl does not belong to a class of chemicals
that would be expected to be immunotoxic.
    c. Therefore, based on the above considerations, EPA does not
believe that conducting immunotoxicity testing will result in a NOAEL
less than the NOAEL of 117 mg//kg/day already established for
thiencarbazone-methyl, and an additional factor (UFDB) for database
uncertainties is not needed to account for potential immunotoxicity.
    ii. There is no indication that thiencarbazone-methyl 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 thiencarbazone-methyl 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. There are no residual uncertainties identified in the exposure
databases. The dietary food exposure assessments were performed based
on 100 PCT and tolerance-level residues. EPA made conservative
(protective) assumptions in the ground water and surface water modeling
used to assess exposure to thiencarbazone-methyl in drinking water. EPA
used similarly conservative assumptions to assess postapplication
exposure of children as well as incidental oral exposure of toddlers.
These assessments will not underestimate the exposure and risks posed
by thiencarbazone-methyl.

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-term, intermediate-term, 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. An acute aggregate risk assessment takes into
account exposure estimates from acute dietary consumption of food and
drinking water. No adverse effect resulting from a single-oral exposure
was identified and no acute dietary endpoint was selected. Therefore,
thiencarbazone-methyl is not expected to pose an acute risk.
    2. Chronic risk. Using the exposure assumptions described in this
unit for chronic exposure, EPA has concluded that chronic exposure to
thiencarbazone-methyl from food and water will utilize 0.1% of the cPAD
for children 1-2 yrs. and children 3-5 yrs. and <0.1% for all other
population subgroups.
    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).
    Thiencarbazone-methyl is currently pending registration for uses
that could result in short-term residential exposure and the Agency has
determined that it is appropriate to aggregate chronic exposure through
food and water with short-term residential exposures to thiencarbazone-
methyl.
    Using the exposure assumptions described in this unit for short-
term exposures, EPA has concluded the combined short-term food, water,
and residential exposures aggregated result in aggregate MOEs of 18,700
to adults and 13,500 to children.
    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).
    Although intermediate-term residential exposure could result from
the use of thiencarbazone-methyl, no toxicological effects resulting
from intermediate-term dosing were observed. Therefore, the aggregate
risk is the sum of the risk from food and water and will not be greater
than the chronic aggregate risk.
    5. Aggregate cancer risk for U.S. population. Thiencarbazone-methyl
is not likely to be carcinogenic to humans. The cRfD of 117 mg/kg/day
is adequately protective of any cancer or pre-cancerous effects seen in
carcinogenicity studies in rats and mice and as the chronic risk
assessment shows estimated exposure to thiencarbazone-methyl is well
below the cRfD.
    6. Determination of safety. Based on these risk assessments, EPA
concludes that there is a reasonable certainty that no harm will result
to the general population, or to infants and children from aggregate
exposure to thiencarbazone-methyl residues.

IV. Other Considerations

A. Analytical Enforcement Methodology

    A high performance liquid chromotography/mass spectrometry/mass
spectrometry (HPLC/MS/MS) method was submitted for the determination of
residues of thiencarbazone-methyl and two metabolites in/on samples of
crop commodities. The validated limit of quantification (LOQ) is 0.01
ppm for each analyte in each matrix. A HPLC/MS/MS method was submitted
for the determination of residues of thiencarbazone-methyl in livestock
commodities. The LOQ is 0.01 ppm.
    Adequate enforcement methodology 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

    EPA established tolerances are harmonized with Maximum Residue
Limits (MRLs) established in Canda, except for tolerances on livestock
commodities, livestock feedstuffs, and soybeans (as a rotational crop).

C. Revisions to Petitioned-For Tolerances

    Tolerance levels and commodity expressions have been revised for
corn, field, forage; corn, field, stover; corn, sweet, forage; corn,
sweet, stover; wheat, forage; wheat, hay; wheat, straw; and livestock
commodities as a result of the

[[Page 60968]]

review of the actual residue data and so that the listed commodities
agree with current EPA commodity terms. EPA concluded that there is no
need to establish indirect or inadvertent tolerance levels in or on
cotton gin byproducts or soybean, seed because the submitted field
rotational crop data demonstrated that residues were not likely to be
found on these commodities when the plant back intervals specified on
the product labels are followed. EPA determined that the residue(s) of
concern for both risk assessment and tolerance expression is
thiencarbazone-methyl for corn and wheat commodities, thiencarbazone-
methyl and BYH 18636-MMT-glucoside for soybean rotational crop commodities,
and thiencarbazone-methyl and BYH 18636-MMT for livestock commodities.

V. Conclusion

    Therefore EPA is establishing tolerances for residues of
thiencarbazone-methyl, in or on corn, field, forage at 0.04 ppm; corn,
field, grain at 0.01 ppm; corn, field, stover at 0.02 ppm; corn, pop,
grain at 0.01 ppm; corn, pop, stover at 0.01 ppm; corn, sweet, forage
at 0.05 ppm; corn, sweet, kernel plus cob with husks removed at 0.01
ppm; corn, sweet, stover at 0.05 ppm; wheat, forage at 0.10 ppm; wheat,
grain at 0.01 ppm; wheat, hay at 0.01 ppm; and wheat, straw at 0.01
ppm; combined residues of thiencarbazone-methyl and its metabolite BYH
18636-MMT, calculated as the parent compound, in or on cattle, meat at
0.02 ppm; cattle, meat byproducts at 0.02 ppm; goat, meat at 0.02 ppm;
goat, meat byproducts at 0.02 ppm; horse, meat at 0.02 ppm; horse, meat
byproducts at 0.02 ppm; milk at 0.02 ppm; sheep, meat at 0.02 ppm; and
sheep, meat byproducts at 0.02 ppm; and indirect or inadvertent
combined residues of thiencarbazone-methyl and its metabolite BYH
18636-MMT-glucoside, calculated as the parent compound, in or on
soybean, forage at 0.04 ppm and soybean, hay at 0.15 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, entitled 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: September 29, 2008.
Debra Edwards,
Director, 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 180.645 is added to read as follows:

Sec.  180.645  Thiencarbazone-methyl; tolerances for residues

    (a) General. (1) Tolerances are established for residues of
thiencarbazone-methyl [methyl 4-[[[(4,5-dihydro-3-methoxy-4-methyl-5-
oxo-1H-1,2,4-triazol-1-yl)-carbonyl]amino]sulfonyl]-5-methyl-3-
thiophenecarboxylate], per se, in or on the following food and feed
commodities:

------------------------------------------------------------------------
                      Commodity                        Parts per million
------------------------------------------------------------------------
Corn, field, forage..................................               0.04
Corn, field, grain...................................               0.01
Corn, field, stover..................................               0.02
Corn, pop, grain.....................................               0.01
Corn, pop, stover....................................               0.01
Corn, sweet, forage..................................               0.05
Corn, sweet, kernel plus cob with husks removed......               0.01
Corn, sweet, stover..................................               0.05
Wheat, forage........................................               0.10
Wheat, grain.........................................               0.01
Wheat, hay...........................................               0.01
Wheat, straw.........................................               0.01
------------------------------------------------------------------------

    (2) Tolerances are established for combined residues of
thiencarbazone-methyl and its metabolite BYH 18636-MMT [5-methoxy-4-
methyl-2,4-dihydro-3H-1,2,4-triazol-3-one], calculated as the parent
compound, in or on the following food commodities of animal origin:

[[Page 60969]]

------------------------------------------------------------------------
                      Commodity                        Parts per million
------------------------------------------------------------------------
Cattle, meat.........................................               0.02
Cattle, meat byproducts..............................               0.02
Goat, meat...........................................               0.02
Goat, meat byproducts................................               0.02
Horse, meat..........................................               0.02
Horse, meat byproducts...............................               0.02
Milk.................................................               0.02
Sheep, meat..........................................               0.02
Sheep, meat byproducts...............................               0.02
------------------------------------------------------------------------

    (b) Section 18 emergency exemptions. [Reserved]
    (c) Tolerances with regional registrations. [Reserved]
    (d) Indirect or inadvertent residues. Tolerances are established
for indirect or inadvertent combined residues of thiencarbazone-methyl
and its metabolite BYH 18636-MMT-glucoside [2-hexopyranosyl-5-methoxy-
4-methyl-2,4-dihydro-3H-1,2,4-triazol-3-one], calculated as the parent
compound, in or on the following food commodities:

------------------------------------------------------------------------
                      Commodity                        Parts per million
------------------------------------------------------------------------
Soybean, forage......................................               0.04
Soybean, hay.........................................               0.15
------------------------------------------------------------------------

[FR Doc. E8-24040 Filed 10-14-08; 8:45 am]
BILLING CODE 6560-50-S

 
 


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