
[Federal Register: September 3, 2010 (Volume 75, Number 171)]
[Rules and Regulations]               
[Page 54033-54040]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr03se10-17]                         

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 180

[EPA-HQ-OPP-2009-0910; FRL-8842-7]

 
Thiabendazole; Pesticide Tolerances

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

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SUMMARY: This regulation establishes tolerances for residues of 
thiabendazole, and its metabolites, benzimidazole (free and 
conjugated), [2-(4-thiazolyl) benzimidazole], in or on corn. Syngenta 
Crop Protection requested these tolerances under the Federal Food, 
Drug, and Cosmetic Act (FFDCA).

DATES: This regulation is effective September 3, 2010. Objections and 
requests for hearings must be received on or before November 2, 2010, 
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-2009-0910. 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 available only in hard copy form. 
Publicly available docket materials are

[[Page 54034]]

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: Janet Whitehurst, Office of Pesticide 
Programs, Environmental Protection Agency, 1200 Pennsylvania Ave., NW., 
Washington, DC 20460-0001; telephone number: (703) 305-6129; e-mail 
address: whitehurst.janet@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 Get Electronic Access to Other Related Information?

    You may access a frequently updated electronic version of EPA's 
tolerance regulations at 40 CFR part 180 through the Government 
Printing Office's e-CFR site at http://www.gpoaccess.gov/ecfr.

C. How Can I File an Objection or Hearing Request?

    Under FFDCA section 408(g), 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-2009-0910 in the subject line on the first 
page of your submission. All objections and requests for a hearing must 
be in writing, and must be received by the Hearing Clerk on or before 
November 2, 2010. Addresses for mail and hand delivery of objections 
and hearing requests are provided in 40 CFR 178.25(b).
    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. Information not marked confidential pursuant to 40 CFR part 2 
may be disclosed publicly by EPA without prior notice. Submit a copy of 
your non-CBI objection or hearing request, identified by docket ID 
number EPA-HQ-OPP-2009-0910, 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. Summary of Petitioned-For Tolerance

    In the Federal Register of June 6, 2010 (75 FR 35804) (FRL-8831-3), 
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 0F7730) 
by Syngenta Crop Science. The petition requested that 40 CFR 180.242 be 
amended by establishing tolerances for residues of the fungicide 
thiabendazole, and its metabolites, benzimidazole (free and 
conjugated), [2-(4-thiazolyl) benzimidazole], in or on corn grain and 
other corn commodities at 0.01 parts per million (ppm). That notice 
referenced a summary of the petition prepared by Syngenta Crop 
Protection, the registrant, which is available in the docket, http://
www.regulations.gov. There were no comments received in response to the 
notice of filing.

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 thiabendazole including 
exposure resulting from the tolerances established by this action. 
EPA's assessment of exposures and risks associated with thiabendazole 
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 target organs for thiabendazole toxicity are the liver and 
thyroid. Effects to these organs were observed in multiple studies and 
across species. Thiabendazole causes thyroid tumors in male rats 
through an established non-linear mode of action involving perturbation 
of thyroid hormone synthesis. Accordingly, thiabendazole is classified 
as ``not likely to be carcinogenic to humans at doses that do not alter 
rat thyroid hormone homeostasis.'' There is no evidence of 
neurotoxicity in the existing database,

[[Page 54035]]

and in developmental and reproductive studies, effects to offspring are 
observed only at doses toxic to the parents. There are no effects seen 
in the toxicity database that would be attributable to a single 
exposure of thiabendazole. The Agency is regulating chronic dietary 
risk with a chronic RfD at a dose below which thyroid hormone balance 
is not impacted and consequently is protective of potential 
carcinogenic effects.
    Specific information on the studies received and the nature of the 
adverse effects caused by thiabendazole 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 the document entitled ``Thiabendazole Human 
Health Risk Assessment for Seed Treatment Use on Corn,'' pages 6-11 in 
docket ID number EPA-HQ-OPP-2007-0546.

B. Toxicological Points of Departure/Levels of Concern

    Once a pesticide's toxicological profile is determined, EPA 
identifies toxicological points of departure (POD) and levels of 
concern to use in evaluating the risk posed by human exposure to the 
pesticide. For hazards that have a threshold below which there is no 
appreciable risk, the toxicological POD is used as the basis for 
derivation of reference values for risk assessment. PODs are developed 
based on a careful analysis of the doses in each toxicological study to 
determine the dose at which no adverse effects are observed (the NOAEL) 
and the lowest dose at which adverse effects of concern are identified 
(the LOAEL). Uncertainty/safety factors are used in conjunction with 
the POD to calculate a safe exposure level--generally referred to as a 
population-adjusted dose (PAD) or a reference dose (RfD), and a safe 
margin of exposure (MOE). 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 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 thiabendazole used for 
human risk assessment is shown in the following Table 1.

     Table 1.--Summary of Toxicological Doses and Endpoints for Thiazbendazole for Use in Human Health Risk
                                                   Assessment
----------------------------------------------------------------------------------------------------------------
                                                                           Level of Concern        Study and
        Exposure/Scenario         Point of Departure   Uncertainty/FQPA        for Risk          Toxicological
                                                            Factors           Assessment            Effects
----------------------------------------------------------------------------------------------------------------
Acute dietary (general                No effect attributable to a single dose seen in the
 population including females 13-                           database
 49 years)
----------------------------------------------------------------------------------------------------------------
Chronic dietary                   NOAEL = 10 mg/kg/   UFA = 3x            cRfD = 0.033 mg/kg/ 2-Year Feed/
                                   day                UFH = 10x.........   day                 Chronic
                                                      FQPA = UFDB = 10x.  cPAD = 0.033 mg/kg/  Carcinogenicity
                                                                           day.                in the Rat
                                                                                              LOAEL = 30 mg/kg/
                                                                                               day based on
                                                                                               decreased body
                                                                                               weight gains and
                                                                                               histopathological
                                                                                               changes in liver
                                                                                               and thyroid
----------------------------------------------------------------------------------------------------------------
Incidental oral (ST/IT)           NOAEL = 10 mg/kg/   UFA = 3x            LOC for MOE = 300   Subchronic oral
                                   day                UFH = 10x.........                       toxicity study -
                                                      FQPA = UFDB = 10x.                       rat
                                                                                              LOAEL = 40 mg/kg/
                                                                                               day based on
                                                                                               reduced body
                                                                                               weight gains and
                                                                                               histopathological
                                                                                               changes in the
                                                                                               bone marrow,
                                                                                               liver and thyroid
Dermal short-term (1-30 days)     NOAEL= 10 mg/kg/    UFA = 3x            Occupational and    Subchronic oral
 DAF = 0.5%                        day                UFH = 10..........   residential LOC     toxicity study -
                                                      FQPA = UFDB = 10x.   for MOE = 300       rat
                                                                                              LOAEL = 40 mg/kg/
                                                                                               day based on
                                                                                               reduced body
                                                                                               weight gains and
                                                                                               histopathological
                                                                                               changes in the
                                                                                               bone marrow,
                                                                                               liver and thyroid
Inhalation short-term (1-30       NOAEL = 10 mg/kg/   UFA = 3x            Occupational LOC    Subchronic oral
 days)                             day                UFH =10x..........   for MOE = 300       toxicity study -
                                                      FQPA = UFDB = 10x.                       rat
                                                                                              LOAEL = 40 mg/kg/
                                                                                               day based on
                                                                                               reduced body
                                                                                               weight gains and
                                                                                               histopathological
                                                                                               changes in the
                                                                                               bone marrow,
                                                                                               liver and thyroid

[[Page 54036]]


Dermal intermediate-term (1-6     NOAEL = 10 mg/kg/   UFA = 3x            Occupational LOC    Subchronic oral
 mos) DAF = 0.5%*                  day                UFH = 10x.........   for MOE = 300       toxicity study -
                                                      FQPA = UFDB = 10x.                       rat
                                                                                              LOAEL = 40 mg/kg/
                                                                                               day based on
                                                                                               reduced body
                                                                                               weight gains and
                                                                                               histopathological
                                                                                               changes in the
                                                                                               bone marrow,
                                                                                               liver and thyroid
Inhalation intermediate-term (1-  NOAEL = 10 mg/kg/   UFA = 3x            Occupational LOC    Subchronic oral
 6 mos)                            day                UFH = 10x.........   for MOE = 300       toxicity study -
                                                      FQPA = UFDB = 10x.                       rat
                                                                                              LOAEL = 40 mg/kg/
                                                                                               day based on
                                                                                               reduced body
                                                                                               weight gains and
                                                                                               histopathological
                                                                                               changes in the
                                                                                               bone marrow,
                                                                                               liver and thyroid
Cancer (all routes)               Not likely to be carcinogenic to humans at doses that do not alter rat thyroid
                                                                hormone homeostasis
----------------------------------------------------------------------------------------------------------------
 UFA = extrapolation from animal to human (interspecies).
UFH = potential variation in sensitivity among members of the human population (intraspecies).
UFDB = to account for the absence of data or other data deficiency.
FQPA SF = Food Quality Protection Act Safety Factor.
PAD = population adjusted dose (a = acute, c = chronic).
RfD = reference dose. MOE = margin of exposure.
LOC = level of concern.

    The overall composite uncertainty factor for assessing 
thiabendazole risk is 300X. That is based on a 10X for intraspecies 
variability among humans, 3X for interspecies pharmacokinetic 
differences between humans and rats, and 10X for FQPA safety factor for 
database uncertainty. The 3X interspecies factor was chosen because the 
endpoint used for the Point of Departure is a thyroid effect and adult 
rats are known to be more sensitive pharmacodynamically to thyroid 
toxicants than humans. Focusing on the thyroid effects will produce the 
most protective PAD despite the fact that a reduced interspecies factor 
is appropriate as to this effect.

C. Exposure Assessment

    1. Dietary exposure from food and feed uses. In evaluating dietary 
exposure to thiabendazole, EPA considered exposure under the 
petitioned-for tolerances as well as all existing thiabendazole 
tolerances in 40 CFR 180.242. EPA assessed dietary exposures from 
thiabendazole in food as follows:
    i. Acute exposure. Quantitative acute dietary exposure and risk 
assessments are performed for a food-use pesticide, if a toxicological 
study has indicated the possibility of an effect of concern occurring 
as a result of a 1-day or single exposure. No such effects were 
identified in the toxicological studies for thiabendazole; therefore, a 
quantitative acute dietary exposure assessment is unnecessary.
    ii. Chronic exposure. Thiabendazole chronic dietary exposure 
assessments were conducted using the DEEM-FCID\TM\ (ver. 2.03) which 
incorporates consumption data from the United States Department of 
Agriculture (USDA) Continuing Survey of Food Intake by Individuals 
(CSFII) (1994-1996 and 1998). In estimating residue levels on food, EPA 
assumed residues in corn were at tolerances levels. For other 
commodities, EPA estimated residue levels based on residue monitoring 
data. EPA also used percent crop treated (PCT) data on some 
commodities.
    iii. Anticipated residue and PCT information. Section 408(b)(2)(E) 
of FFDCA authorizes EPA to use available data and information on the 
anticipated residue levels of pesticide residues in food and the actual 
levels of pesticide residues that have been measured in food. If EPA 
relies on such information, EPA must require pursuant to FFDCA section 
408(f)(1) that data be provided 5 years after the tolerance is 
established, modified, or left in effect, demonstrating that the levels 
in food are not above the levels anticipated. For the present action, 
EPA will issue such data call-ins as are required by FFDCA section 
408(b)(2)(E) and authorized under FFDCA section 408(f)(1). Data will be 
required to be submitted no later than 5 years from the date of 
issuance of these tolerances.
    Section 408(b)(2)(F) of FFDCA states that the Agency may use data 
on the actual percent of food treated for assessing chronic dietary 
risk only if:
     Condition a: The data used are reliable and provide a 
valid basis to show what percentage of the food derived from such crop 
is likely to contain the pesticide residue.
     Condition b: The exposure estimate does not underestimate 
exposure for any significant subpopulation group.
     Condition c: Data are available on pesticide use and food 
consumption in a particular area, the exposure estimate does not 
understate exposure for the population in such area.
    In addition, the Agency must provide for periodic evaluation of any 
estimates used. To provide for the periodic evaluation of the estimate 
of PCT as required by FFDCA section 408(b)(2)(F), EPA may require 
registrants to submit data on PCT.
    The following PCT were used in the assessment:
     Apple 30%.
     Orange 20%.
     Pear 45%.
     Potato 1%.
     Soybeans 1%.
     Strawberry 6.3% imported.
     Sweet potato 1%.
     Wheat 1%.
    In most cases, EPA uses available data from USDA/National 
Agricultural

[[Page 54037]]

Statistics Service (NASS), proprietary market surveys, and the National 
Pesticide Use Database for the chemical/crop combination for the most 
recent 6-7 years. EPA uses an average PCT for chronic dietary risk 
analysis. The average PCT figure for each existing use is derived by 
combining available public and private market survey data for that use, 
averaging across all observations, and rounding to the nearest 5%, 
except for those situations in which the average PCT is less than one. 
In those cases, 1% is used as the average PCT and 2.5% is used as the 
maximum PCT. EPA uses a maximum PCT for acute dietary risk analysis. 
The maximum PCT figure is the highest observed maximum value reported 
within the recent 6 years of available public and private market survey 
data for the existing use and rounded up to the nearest multiple of 5%.
    The Agency believes that the three conditions discussed above have 
been met. With respect to Condition a, PCT estimates are derived from 
Federal and private market survey data, which are reliable and have a 
valid basis. The Agency is reasonably certain that the percentage of 
the food treated is not likely to be an underestimation. As to 
Conditions b and c, regional consumption information and consumption 
information for significant subpopulations is taken into account 
through EPA's computer-based model for evaluating the exposure of 
significant subpopulations including several regional groups. Use of 
this consumption information in EPA's risk assessment process ensures 
that EPA's exposure estimate does not understate exposure for any 
significant subpopulation group and allows the Agency to be reasonably 
certain that no regional population is exposed to residue levels higher 
than those estimated by the Agency. Other than the data available 
through national food consumption surveys, EPA does not have available 
reliable information on the regional consumption of food to which 
thiabendazole may be applied in a particular area.
    iv. Cancer. EPA has concluded that thiabendazole does not pose a 
cancer risk to humans. Therefore, a dietary exposure assessment for the 
purpose of assessing cancer risk is unnecessary.
    2. Dietary exposure from drinking water. The Agency used screening 
level water exposure models in the dietary exposure analysis and risk 
assessment for thiabendazole drinking water. These simulation models 
take into account data on the physical, chemical, and fate/transport 
characteristics of thiabendazole. 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.
    A Tier 2 drinking water assessment was conducted for thiabendazole 
in surface water and Tier 1 in ground water for the proposed new seed 
treatment product on corn. The annual mean concentration of 0.0000048 
ppm was used in the chronic dietary exposure analysis. Drinking water 
concentrations from ground water sources were estimated, but were lower 
than that estimated concentration from surface water, so the estimated 
concentration from surface water sources was used in the dietary 
exposure analysis.
    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).
    Thiabendazole is currently registered for the following uses that 
could result in residential exposures: paint and sponges. These 
residential uses have been assessed and aggregated with the food and 
water exposures. EPA assumed that 5% of the thiabendazole on sponges is 
transferred to the surface being wiped (such as counters, tables, 
floors) each day. Further information regarding EPA standard 
assumptions and generic inputs for residential exposures may be found 
at http://www.epa.gov/pesticides/trac/science/trac6a05.pdf.
    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.''
     EPA has not found thiabendazole to share a common mechanism of 
toxicity with any other substances, and thiabendazole does not appear 
to produce a toxic metabolite produced by other substances. For the 
purposes of this tolerance action, therefore, EPA has assumed that 
thiabendazole does not have a common mechanism of toxicity with other 
substances. For information regarding EPA's efforts to determine which 
chemicals have a common mechanism of toxicity and to evaluate the 
cumulative effects of such chemicals, see EPA's website at http://
www.epa.gov/pesticides/cumulative.

D. Safety Factor for Infants and Children

    1. In general. Section 408(b)(2)(C) of FFDCA provides that EPA 
shall apply an additional tenfold (10X) margin of safety for infants 
and children in the case of threshold effects to account for prenatal 
and postnatal toxicity and the completeness of the database on toxicity 
and exposure unless EPA determines based on reliable data that a 
different margin of safety will be safe for infants and children. This 
additional margin of safety is commonly referred to as the FQPA Safety 
Factor (SF). In applying this provision, EPA either retains the default 
value of 10X, or uses a different additional safety factor when 
reliable data available to EPA support the choice of a different 
factor.
    2. Prenatal and postnatal sensitivity. In prenatal developmental 
toxicity studies in rats, rabbits, and mice and in the 2-generation 
reproduction study in rats, effects in the fetuses or neonates occurred 
at or above doses that caused maternal or parental toxicity.
    3. Conclusion. EPA is retaining a FQPA factor of 10X based on the 
following findings:
    i. The database for thiabendazole is complete except for a 
developmental thyroid study and data needed for the new data 
requirements including an immunotoxicity study and the neurotoxicity 
screening battery. Pending the outcome of the developmental thyroid 
toxicity study, there is uncertainty with respect to the effect of 
thiabendazole in developing offspring. There is evidence of thyroid 
toxicity following subchronic and chronic exposures to rats 
characterized as histopathological changes in the thyroid in multiple 
studies in rats. Disruption of thyroid homeostasis is the initial, 
critical effect that may lead to adverse effects on the developing 
nervous system. Thus, the absence of the developmental thyroid study 
raises concern whether infants and children are sufficiently protected 
from developmental effects. The developmental thyroid toxicity study 
will better address this concern than a developmental neurotoxicity 
study. The absence of neurotoxicity studies (acute, subchronic, and 
developmental) raise relatively low concern because: (1) Thiabendazole 
has shown no indication of neurotoxicity in relevant studies, and; (2) 
to the extent that thiabendazole's thyroid effects may have 
neurological effects on the young, the nature of the thyroid effects 
(and the potential for any resulting neurological effects on the young) 
will be addressed by the developmental thyroid study. The

[[Page 54038]]

absence of the immunotoxicity study raises relatively low concern 
because there are no indications in the available studies that organs 
associated with immune function, such as the thymus and spleen, are 
affected by thiabendazole.
    ii. There is no evidence that thiabendazole 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.
    iii. There are no residual uncertainties identified in the exposure 
databases. The dietary food exposure assessments were performed based 
on PCT and anticipated residues primarily from Pesticide Data Program 
(PDP) data and some tolerance-level residues. These data are reliable 
and will not underestimate the exposure and risk. EPA made conservative 
(protective) assumptions in the ground water and surface water modeling 
used to assess exposure to thiabendazole 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 
thiabendazole.

E. Aggregate Risks and Determination of Safety

    EPA determines whether acute and chronic dietary pesticide 
exposures are safe by comparing aggregate exposure estimates to the 
acute population adjusted dose (aPAD) and chronic PAD (cPAD). For 
linear cancer risks, EPA calculates the lifetime probability of 
acquiring cancer 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 
appropriate PODs to ensure that an adequate MOE exists.
    1 Acute risk. An acute aggregate risk assessment takes into account 
acute exposure estimates from 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, 
thiabendazole 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 
thiabendazole from food and water will utilize 1.4% of the cPAD 
occupied for the U.S. population. The most highly exposed subpopulation 
was all infants at 4.6% cPAD.
    3. Short- and intermediate-term risk. Short-term and intermediate-
term aggregate exposure takes into account short-term residential 
exposure plus chronic exposure to food and water (considered to be a 
background exposure level). To assess short-term and intermediate-term 
aggregate risk likely to result from the new and existing thiabendazole 
uses, EPA combined average food and water exposures with estimates of 
residential exposure for both adult painters and adult females and 
small children exposed to surfaces cleaned with treated sponges.
    No risks of concern were seen for adult painters. A potential risk 
of concern would be the use of thiabendazole treated sponges, if the 
Agency assumes that 100% of the thiabendazole on a treated sponge is 
transferred to surfaces each day. It is very unlikely that a sponge 
would release all of the thiabendazole used to treat it in a single 
day, and the user would use a new sponge every day. Since this is a 
very unrealistic assumption, a second aggregate assessment was 
conducted assuming that 100% of the thiabendazole on a treated sponge 
is transferred to surfaces over 20 days and that each 20 days the user 
would use a new sponge. This assumption is still conservative because: 
(1) Sponges will generally be used much longer than 20 days; (2) it is 
very unlikely that 100% of the thiabendazole would be released from the 
sponge in such a short period given that environmental fate data show 
thiabendazole to have low water solubility indicating that 
thiabendazole will bind strongly to the sponge; and (3) it is very 
unlikely that 100% of any released thiabendazole would be transferred 
to countertops because this assumption does not account for any 
thiabendazole that is washed down the sink or that normally degrades. 
With this assumption, none of the aggregate exposures represent risks 
of concern, as all MOEs are greater than the target MOE of 300.
    A summary of the short-term and intermediate-term aggregate risk 
for thiabendazole used in the human risk assessment is shown in Tables 
2 and 3 of this unit.

                Table 2.--Short-Term and Intermediate-Term Aggregate Risk for Residential Painter
----------------------------------------------------------------------------------------------------------------
                                        Average Food and Water   Residential Exposure1   Aggregate MOE (food and
         Population Subgroup             Exposure (mg/kg/day)         (mg/kg/day)             residential)2
----------------------------------------------------------------------------------------------------------------
U.S. Population                                       0.000451                   0.0046                     2000
----------------------------------------------------------------------------------------------------------------
Youth (13-19 yrs)                                     0.000289                   0.0046                     2000
----------------------------------------------------------------------------------------------------------------
Adults (20-49 yrs)                                    0.000308                   0.0046                     2000
----------------------------------------------------------------------------------------------------------------
Adults (50 + yrs)                                     0.000331                   0.0046                     2000
----------------------------------------------------------------------------------------------------------------
Females (13-49 yrs)                                   0.000333                   0.0046                     2000
----------------------------------------------------------------------------------------------------------------
1 Residential Exposure = Dermal exposure + Inhalation Exposure.
2 (Avg Food Aggregate MOE = NOAEL (10 mg/kg/day and Water Exposure + Residential Exposure).


[[Page 54039]]


             Table 3.-Short-Term and Intermediate-Term Aggregate Risk Calculations for Sponge Usage
----------------------------------------------------------------------------------------------------------------
                                        Average Food and Water  Residential Exposure\1\  Aggregate MOE (food and
         Population Subgroup             Exposure (mg/kg/day)         (mg/kg/day)            residential)\2\
----------------------------------------------------------------------------------------------------------------
                    Fraction of Thiabendazole Transferred Daily From Sponge to Surface = 100%
----------------------------------------------------------------------------------------------------------------
Children (3-5 yrs)                                    0.001252                     0.08                      120
----------------------------------------------------------------------------------------------------------------
Females (13-49 yrs)                                   0.000333                     0.02                      500
----------------------------------------------------------------------------------------------------------------
                        Fraction of Thiabendazole Transferred From Sponge to Surface = 5%
----------------------------------------------------------------------------------------------------------------
Children (3-5 yrs)                                    0.001252                    0.004                     2300
----------------------------------------------------------------------------------------------------------------
Females (13-49 yrs)                                   0.000333                    0.001                     4500
----------------------------------------------------------------------------------------------------------------
\1\ Residential Exposure = Dermal exposure + Inhalation Exposure.
\2\ Aggregate MOE = NOAEL (10 mg/kg/day) / (Average Food & Water Exposure plus Residential Exposure).

    5. Aggregate cancer risk for U.S. population. Based on the lack of 
evidence of carcinogenicity in two adequate rodent carcinogenicity 
studies, thiabendazole is not expected to pose a cancer risk to humans.
    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 thiabendazole residues.

IV. Other Considerations

A. Analytical Enforcement Methodology

    Adequate enforcement methodology (spectrophotofluorometric, Methods 
I, A, B and C) is available to enforce the tolerance expression. In all 
of the methods, residues are extracted with ethyl acetate, and the 
extracts are purified by washing with dilute NaOH and/or HCl.
    An high-performance liquid chromatography (HPLC) method with 
fluorescence detection (FLD) is available for the enforcement of 
tolerances for residues of free and conjugated benzimidazole. This 
method is listed in the U.S. EPA Index of Residue Analytical Methods 
under thiabendazole as Study No. 93020 (MRID 43328302).
    In addition, the analytical method used in this petition may be 
used for enforcement. This sample is extracted and hydrolized and 
analyzed by liquid chromatography/mass spectrometry (LC/MS/MS). The 
method limit of quantation (LOQ) is 0.01 ppm, and the limit of 
detection (LOD) is 0.004 ppm. The method was adequately validated using 
samples of field corn forage, grain, and stover, and sweet corn forage 
and K+CWHR fortified with each analyte at 0.01, 0.05, and 0.1 ppm. 
Acceptable concurrent recovery data for the method were also submitted 
and achieved.

B. International Residue Limits

    In making its tolerance decisions, EPA seeks to harmonize U.S. 
tolerances with international standards whenever possible, consistent 
with U.S. food safety standards and agricultural practices. EPA 
considers the international maximum residue limits (MRLs) established 
by the Codex Alimentarius Commission (Codex), as required by FFDCA 
section 408(b)(4). The Codex Alimentarius is a joint U.N. Food and 
Agriculture Organization/World Health Organization food standards 
program, and it is recognized as an international food safety 
standards-setting organization in trade agreements to which the United 
States is a party. EPA may establish a tolerance that is different from 
a Codex MRL; however, FFDCA section 408(b)(4) requires that EPA explain 
the reasons for departing from the Codex level.
     The Codex has not established any MRLs for thiabendazole.

V. Conclusion

    Therefore, tolerances are established for residues of 
thiabendazole, and its metabolites, benzimidazole (free and 
conjugated), [2-(4-thiazolyl) benzimidazole], in or on corn grain and 
other corn commodities at 0.01 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

[[Page 54040]]

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: August 20, 2010.
Lois Rossi,
Director, Registration Division, Office of Pesticide Programs.

0
Therefore, 40 CFR chapter I is amended as follows:

PART 180--[AMENDED]

0
1. The authority citation for part 180 continues to read as follows:

    Authority: 21 U.S.C. 321(q), 346a and 371.

0
2. Section 180.242 is amended by alphabetically adding the following 
commodities to the table in paragraph (a)(1) to read as follows:


Sec.  180.242  Thiabendazole; tolerances for residues.

    (a) * * * (1) * * *

------------------------------------------------------------------------
                                                             Expiration/
                   Commodity                     Parts per    Revocation
                                                  million        Date
------------------------------------------------------------------------
                                * * * * *
Corn, field, forage...........................         0.01         None
Corn, field, grain............................         0.01         None
Corn, field, stover...........................         0.01         None
Corn, pop, forage.............................         0.01         None
Corn, pop, grain..............................         0.01         None
Corn, pop, stover.............................         0.01         None
Corn, sweet, forage...........................         0.01         None
Corn, sweet, kernels plus cop with husks               0.01         None
 removed......................................
Corn, sweet, stover...........................         0.01         None
                                * * * * *
------------------------------------------------------------------------

* * * * *
[FR Doc. 2010-22121 Filed 9-2-10; 8:45 am]
BILLING CODE 6560-50-S

