
[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.

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 180.645 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
