[Federal Register: June 23, 2010 (Volume 75, Number 120)]
[Rules and Regulations]
[Page 35653-35660]
[DOCID:fr23jn10-23]

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 180

[EPA-HQ-OPP-2009-0737; FRL-8830-4]

Thiamethoxam; Pesticide Tolerances

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

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SUMMARY: This regulation establishes tolerances for residues of
thiamethoxam in or on onion, dry bulb. Syngenta Crop Protection, Inc.,
requested these tolerances under the Federal Food, Drug, and Cosmetic
Act (FFDCA).

DATES: This regulation is effective June 23, 2010. Objections and
requests for hearings must be received on or before August 23, 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-2009-0737. 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 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: Julie Chao, Registration Division
(7505P), Office of Pesticide Programs, Environmental Protection Agency,
1200 Pennsylvania Ave., NW., Washington, DC 20460-0001; telephone
number:<PHONE_NUMBER>; e-mail address<EMAIL_ADDRESS>
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-2009-0737 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
August 23, 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-2009-0737, 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<PHONE_NUMBER>.

II. Summary of Petitioned-For Tolerance

    In the Federal Register of January 6, 2010, (75 FR 864) (FRL-8801-
5), 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
9F7582) by Syngenta Crop Protection, Inc., P.O. Box 18300, Greensboro,
NC 27419. The petition requested that 40 CFR 180.565 be amended by
establishing tolerances for residues of the insecticide thiamethoxam
(3-[(2-chloro-5-thiazolyl)methyl]tetrahydro-5-methyl-N-nitro-4H-1,3,5-
oxadiazin-4-imine) and its metabolite CGA-322704 [N-(2-chloro-thiazol-
5-ylmethyl)-N'-methyl-N'-nitro-guanidine], in or on onion, dry bulb at
0.03 parts per million (ppm). That notice referenced a summary of the
petition prepared by Syngenta Crop Protection, Inc., the registrant,
which is available in the docket EPA-HQ-OPP-2009-0737, at 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 thiamethoxam including
exposure resulting from the tolerances established by this action.
EPA's assessment of exposures and risks associated with thiamethoxam
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.
    Thiamethoxam shows toxicological effects primarily in the liver,
kidney, testes, and hematopoietic system. In addition, developmental
neurological effects were observed in rats. This developmental effect
is being used to assess risks associated with acute exposures to
thiamethoxam, and the liver and testicular effects are the bases for
assessing longer term exposures. Although thiamethoxam causes liver
tumors in mice, the Agency has classified thiamethoxam as ``not likely
to be carcinogenic to humans'' based on convincing evidence that a non-
genotoxic mode of action for liver tumors was established in the mouse
and that the carcinogenic effects are a result of a mode of action
dependent on sufficient amounts of a hepatotoxic metabolite produced
persistently. The non-cancer (chronic) assessment is sufficiently
protective of the key events (perturbation of liver metabolism,
hepatotoxicity/regenerative proliferation) in the animal mode of action
for cancer. Refer to the Federal Register of June 22, 2007 (72 FR
34401) (FRL-8133-6) for more information regarding the cancer
classification of thiamethoxam.
    Thiamethoxam produces a metabolite known as CGA-322704 (referred to
in the remainder of this rule as clothianidin). Clothianidin is also
registered as a pesticide. While some of the toxic effects observed
following testing with the thiamethoxam and clothianidin are similar,
the available information indicates that thiamethoxam and clothianidin
have different toxicological effects in mammals and should be assessed
separately. A separate risk assessment of clothianidin has been
completed in conjunction with the registration of clothianidin. The
most recent assessments, which provide details regarding the toxicology
of clothianidin, are available in the docket EPA-HQ-OPP-2008-0945, at
http:// www.regulations.gov. Refer to the documents ``Clothianidin:
Human Health Risk Assessment for Proposed Uses on Berries (Group 13-
07H), Brassica Vegetables (Group 5), Cotton, Cucurbit Vegetables (Group
9), Fig, Fruiting Vegetables (Group 8), Leafy Green Vegetables (Group
4A), Peach, Pomegranate, Soybean, Tree Nuts (Group 14), and Tuberous
and Corm Vegetables (Group 1C);'' and ``Clothianidin: Human Health Risk
Assessment for Proposed Seed Treatment Uses on Root and Tuber
Vegetables (Group 1), Bulb Vegetables (Group 3), Leafy Green Vegetables
(Group 4A), Brassica Leafy Vegetables (Group 5), Fruiting Vegetables
(Group 8), Cucurbit Vegetables (Group 9), and Cereal Grains (Group 15,
except rice).''
    Specific information on the studies received and the nature of the
adverse effects caused by thiamethoxam as well as the no-observed-
adverse-effect-level (NOAEL) and the lowest-observed-adverse-effect-
level (LOAEL) from the toxicity studies are discussed in the final rule
published in the Federal Register of June 22, 2007.

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 thiamethoxam used for
human risk assessment is discussed in Unit III.B of the final rule
published in the Federal Register of June 22, 2007.

C. Exposure Assessment

    1. Dietary exposure from food and feed uses. In evaluating dietary
exposure to thiamethoxam, EPA considered exposure under the petitioned-
for tolerances as well as all existing thiamethoxam tolerances in 40
CFR 180.565. EPA assessed dietary exposures from thiamethoxam in food
as follows:
    For both acute and chronic exposure assessments for thiamethoxam,
EPA combined residues of clothianidin coming from thiamethoxam with
residues of thiamethoxam per se. As discussed in this unit,
thiamethoxam's major metabolite is CGA-322704, which is also the
registered active ingredient clothianidin. Available information
indicates that thiamethoxam and clothianidin have different
toxicological effects in mammals and should be assessed separately;
however, these exposure assessments for this action incorporated the
total residue of thiamethoxam and clothianidin from use of thiamethoxam
because the total residue for each commodity for which thiamethoxam has
a tolerance has not been separated between thiamethoxam and its
clothianidin metabolite. The combining of these residues, as was done
in this assessment, results in highly conservative estimates of dietary
exposure and risk. A separate assessment was done for clothianidin. The
clothianidin assessment included clothianidin residues from use of
clothianidin as a pesticide and clothianidin residues from use of
thiamethoxam on those commodities for which the pesticide clothianidin
does not have a tolerance. As to these commodities, EPA has separated
total residues between thiamethoxam and clothianidin.
    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.
    Such effects were identified for thiamethoxam. In estimating acute
dietary exposure, EPA used food consumption information from the United
States Department of Agriculture (USDA) 1994-1996 and 1998 Nationwide
Continuing Surveys of Food Intake by Individuals (CSFII). As to residue
levels in food, EPA assumed tolerance-level residues of thiamethoxam
and clothianidin. It was also assumed that 100% of crops with
registered or requested uses of thiamethoxam and 100% of crops with
registered or requested uses of clothianidin are treated.
    ii. Chronic exposure. In conducting the chronic dietary exposure
assessment EPA used the food consumption data from the USDA 1994-1996
and 1998 CSFII. As to residue levels in food, EPA assumed tolerance
level and/or anticipated residues from thiamethoxam field trials. It
was also assumed that 100% of crops with registered or requested uses
of thiamethoxam and 100% of crops with registered or requested uses of
clothianidin are treated.
    A complete listing of the inputs used in these assessments can be
found in the following documents ``Thiamethoxam: Acute and Chronic
Aggregate Dietary (Food and Drinking Water) Exposure and Risk
Assessments for the Section 3 Registration as a Seed Treatment on
Onion, Dry Bulb, Removing the Geographical Limitations on the Foliar
Treatment of Barley,'' available in the docket EPA-HQ-OPP-2009-0737, at
http://www.regulations.gov; and ``Clothianidin Acute and Chronic
Aggregate Dietary (Food and Drinking Water) Exposure and Risk
Assessments,'' available in the docket EPA-HQ-OPP- 2008-0945, at http:/
/www.regulations.gov.
    iii. Cancer. EPA concluded that thiamethoxam is ``not likely to be
carcinogenic to humans'' based on convincing evidence that a non-
genotoxic mode of action for liver tumors was established in the mouse,
and that the carcinogenic effects are a result of a mode of action
dependent on sufficient amounts of a hepatotoxic metabolite produced
persistently. The non-cancer (chronic) assessment is sufficiently
protective of the key events (perturbation of liver metabolism,
hepatotoxicity/regenerative proliferation) in the animal mode of action
for cancer and thus a separate exposure assessment pertaining to cancer
risk is not necessary. Because clothianidin is not expected to pose a
cancer risk, a quantitative dietary exposure assessment for the
purposes of assessing cancer risk was not conducted.
    iv. Anticipated residue and percent crop treated (PCT) information.
Section 408(b)(2)(E) of FFDCA authorizes EPA to use available data and
information on the anticipated residue levels of pesticide residues in
food and the actual levels of pesticide 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.
    EPA did not use PCT information in the dietary assessments for
thiamethoxam or clothianidin.
    2. Dietary exposure from drinking water. Thiamethoxam is expected
to be persistent and mobile in terrestrial and aquatic environments.
These fate properties suggest that thiamethoxam has a potential to move
into surface water and shallow ground water. The Agency lacks
sufficient monitoring data to complete a comprehensive dietary exposure
analysis and risk assessment for thiamethoxam in drinking water.
    Because the Agency does not have comprehensive monitoring data, the
Agency used screening level water exposure models in the dietary
exposure analysis and risk assessment for thiamethoxam in drinking
water. These simulation models take into account data on the physical,
chemical, and fate/transport characteristics of thiamethoxam. 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.
    For surface water, the estimated drinking water concentrations
(EDWCs) are based on thiamethoxam concentrations in tail water from
rice paddies and cranberry bogs that drain into adjacent surface water
bodies. Because the uses on rice and cranberries involve flooding, for
which Pesticide Root Zone Model/Exposure/Analysis Modeling System
(PRZM/EXAMS) is not currently parameterized, these uses were assessed
using the modified Tier I Rice Model and the Provisional Cranberry
Model. Exposure estimates were refined with a default percent cropped
area factor of 87%. The Tier I Rice Model is expected to generate
conservative EDWCs that exceed peak measured concentrations of
pesticides in water bodies well downstream of rice paddies by less than
one order of magnitude to multiple orders of magnitude.
    For ground water, the EDWCs are based on thiamethoxam
concentrations resulting from use on grapes. Exposure in ground water
due to leaching was assessed with the Screening

Concentration in Ground water (SCI-GROW) models.
    Based on the Tier I Rice Model and SCI-GROW models, the EDWCs of
thiamethoxam for acute exposures are 131.77 parts per billion (ppb) for
tail water and 4.14 ppb for ground water. The EDWCs for chronic
exposures for non-cancer assessments are 11.31 ppb for tail water and
4.14 ppb for ground water.
    Modeled estimates of drinking water concentrations were directly
entered into the dietary exposure model. The most conservative EDWCs in
both the acute and chronic exposure scenarios were for tail water, and
represent worst case scenarios. Therefore, for the acute dietary risk
assessments for thiamethoxam, the upper-bound EDWC value of 131.77 ppb
was used to assess the contribution to drinking water. For the chronic
dietary risk assessments for thiamethoxam, the upper-bound EDWC value
of 11.31 ppb was used to assess the contribution to drinking water.
    The registrant has conducted small-scale prospective ground water
studies in several locations in the United States to investigate the
mobility of thiamethoxam in a vulnerable hydrogeological setting. A
review of those data show that generally, residues of thiamethoxam, as
well as CGA-322704, are below the limit of quantification (0.05 ppb).
When quantifiable residues are found, they are sporadic and at low
levels. The maximum observed residue levels from any monitoring well
were 1.0 ppb for thiamethoxam and 0.73 ppb for CGA-322704. These values
are well below the modeled estimates summarized in this unit,
indicating that the modeled estimates are, in fact, protective of what
actual exposures are likely to be.
    Clothianidin is not a significant degradate of thiamethoxam in
surface water or ground water sources of drinking water and, therefore,
was not included in the EDWCs used in the thiamethoxam dietary
assessments. For the clothianidin assessments, the acute EDWC value of
7.29 ppb for clothianidin was incorporated into the acute dietary
assessment and the chronic EDWC value of 5.88 ppb for clothianidin was
incorporated into the chronic dietary assessment.
    A complete listing of the inputs used in these assessments can be
found in the following documents ``Thiamethoxam. Acute and Chronic
Aggregate Dietary (Food and Drinking Water) Exposure and Risk
Assessments for the Section 3 Registration as a Seed Treatment on
Onion, Dry Bulb, Removing the Geographical Limitations on the Foliar
Treatment of Barley,'' available in the docket EPA-HQ-OPP-2009-0737, at
http://www.regulations.gov; and ``Clothianidin Acute and Chronic
Aggregate Dietary (Food and Drinking Water) Exposure and Risk
Assessments,'' available in the docket EPA-HQ-OPP-2008-0945, at http://
www.regulations.gov.
    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).
    Thiamethoxam is currently registered for the following uses that
could result in residential exposures: Turfgrass on golf courses,
residential lawns, commercial grounds, parks, playgrounds, athletic
fields, landscapes, interiorscapes, and sod farms; indoor crack and
crevice or spot treatments to control insects in residential settings.
EPA assessed residential exposure using the following assumptions:
    Thiamethoxam is registered for use on turfgrass (on golf courses,
residential lawns, commercial grounds, parks, playgrounds, athletic
fields, landscapes, interiorscapes and sod farms) and for indoor use to
control insects in residential settings. Thiamethoxam is applied by
commercial applicators only. Therefore, exposures resulting to
homeowners from applying thiamethoxam were not assessed. However,
entering areas previously treated with thiamethoxam could lead to
exposures for adults and children. As a result, risk assessments have
been completed for post-application scenarios.
    Short-term exposures (1 to 30 days of continuous exposure) may
occur as a result of activities on treated turf. Short-term and
intermediate-term exposures (30 to 90 days of continuous exposure) may
occur as a result of entering indoor areas previously treated with a
thiamethoxam indoor crack and crevice product. The difference between
short-term and intermediate-term aggregate risk is the frequency of
hand-to-mouth events for children. For short-term exposure there are 20
events per hour and for intermediate-term exposure there are 9.5 events
per hour. The doses and end-points for short-term and intermediate-term
aggregate risk are the same.
    EPA combined all non-dietary sources of post-application exposure
to obtain an estimate of potential combined exposure. These scenarios
consisted of adult and toddler dermal post-application exposure and
oral (hand-to-mouth) exposures for toddlers. Since post-application
scenarios for turf occur outdoors, the potential for inhalation
exposure is negligible and therefore does not require an inhalation
exposure assessment. Since thiamethoxam has a very low vapor pressure
(6.6 x 10-9 Pa @ 25[deg]C), inhalation exposure is also expected to be
negligible as a result of indoor crack and crevice use. Therefore, a
quantitative post-application inhalation exposure assessment was not
performed.
    A complete listing of the inputs used in these assessments can be
found in the following documents ``Thiamethoxam: Occupational and
Residential Exposure/Risk Assessment for Proposed Section 3
Registration for Seed Treatment Use on Bulb Onions,'' available in the
docket EPA-HQ-OPP-2009-0737, at http://www.regulations.gov.
    Thiamethoxam use on turf or as an indoor crack and crevice or spot
treatment does not result in significant residues of clothianidin. In
addition, clothianidin residential and aggregate risks are not of
concern. For further details, refer to the documents ''Clothianidin:
Human Health Risk Assessment for Proposed Uses on Berries (Group 13-
07H), Brassica Vegetables (Group 5), Cotton, Cucurbit Vegetables (Group
9), Fig, Fruiting Vegetables (Group 8), Leafy Green Vegetables (Group
4A), Peach, Pomegranate, Soybean, Tree Nuts (Group 14), and Tuberous
and Corm Vegetables (Group 1C);'' and ``Clothianidin: Human Health Risk
Assessment for Proposed Seed Treatment Uses on Root and Tuber
Vegetables (Group 1), Bulb Vegetables (Group 3), Leafy Green Vegetables
(Group 4A), Brassica Leafy Vegetables (Group 5), Fruiting Vegetables
(Group 8), Cucurbit Vegetables (Group 9), and Cereal Grains (Group 15,
except rice),'' available in the docket EPA-HQ-OPP-2008-0945, at http:/
//www.regulations.gov.
    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.''
    Thiamethoxam is a member of the neonicotinoid class of pesticides
and produces, as a metabolite, another neonicotinoid, clothianidin.
Structural

similarities or common effects do not constitute a common mechanism of
toxicity. Evidence is needed to establish that the chemicals operate by
the same, or essentially the same sequence of major biochemical events
(EPA, 2002). Although clothianidin and thiamethoxam bind selectively to
insect nicotinic acetylcholine receptors (nAChR), the specific binding
site(s)/receptor(s) for clothianidin, thiamethoxam, and the other
neonicotinoids are unknown at this time. Additionally, the commonality
of the binding activity itself is uncertain, as preliminary evidence
suggests that clothianidin operates by direct competitive inhibition,
while thiamethoxam is a non-competitive inhibitor. Furthermore, even if
future research shows that neonicotinoids share a common binding
activity to a specific site on insect nicotinic acetylcholine
receptors, there is not necessarily a relationship between this
pesticidal action and a mechanism of toxicity in mammals. Structural
variations between the insect and mammalian nAChRs produce quantitative
differences in the binding affinity of the neonicotinoids towards these
receptors, which, in turn, confers the notably greater selective
toxicity of this class towards insects, including aphids and
leafhoppers, compared to mammals. While the insecticidal action of the
neonicotinoids is neurotoxic, the most sensitive regulatory endpoint
for thiamethoxam is based on unrelated effects in mammals, including
effects on the liver, kidney, testes, and hematopoietic system.
Additionally, the most sensitive toxicological effect in mammals
differs across the neonicotinoids (e.g., testicular tubular atrophy
with thiamethoxam; mineralized particles in thyroid colloid with
imidacloprid).
    Thus, EPA has not found thiamethoxam or clothianidin to share a
common mechanism of toxicity with any other substances. For the
purposes of this tolerance action, therefore, EPA has assumed that
thiamethoxam and clothianidin do 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 the developmental
studies, there is no evidence of increased quantitative or qualitative
susceptibility of rat or rabbit fetuses to in utero exposure to
thiamethoxam. The developmental NOAELs are either higher than or equal
to the maternal NOAELs. The toxicological effects in fetuses do not
appear to be any more severe than those in the dams or does. In the rat
developmental neurotoxicity study, there was no quantitative evidence
of increased susceptibility.
    There is evidence of increased quantitative susceptibility for male
pups in 2-generation reproductive studies. In one study, there are no
toxicological effects in the dams whereas for the pups, reduced
bodyweights are observed at the highest dose level, starting on day 14
of lactation. This contributes to an overall decrease in bodyweight
gain during the entire lactation period. Additionally, reproductive
effects in males appear in the F1 generation in the form of increased
incidence and severity of testicular tubular atrophy. These data are
considered to be evidence of increased quantitative susceptibility for
male pups (increased incidence of testicular tubular atrophy at 1.8
milligrams/kilogram/day (mg/kg/day) when compared to the parents
(hyaline changes in renal tubules at 61 mg/kg/day; NOAEL is 1.8 mg/kg/
day).
    In a more recent 2-generation reproduction study, the most
sensitive effect was sperm abnormalities at 3 mg/kg/day (the NOAEL is
1.2 mg/kg/day) in the F1 males. This study also indicates increased
susceptibility for the offspring for this effect.
    Although there is evidence of increased quantitative susceptibility
for male pups in both reproductive studies, NOAELs and LOAELs were
established in these studies and the Agency selected the NOAEL for
testicular effects in F1 pups as the basis for risk assessment. The
Agency has confidence that the NOAEL selected for risk assessment is
protective of the most sensitive effect (testicular effects) for the
most sensitive subgroup (pups) observed in the toxicological database.
    3. Conclusion. a. In the final rule published in the Federal
Register of January 5, 2005 (70 FR 708) (FRL-7689-7), EPA had
previously determined that the FQPA SF should be retained at 10X for
thiamethoxam, based on the following factors: Effects on endocrine
organs observed across species; significant decrease in alanine amino
transferase levels in companion animal studies and in dog studies; the
mode of action of this chemical in insects (interferes with the
nicotinic acetylcholine receptors of the insect's nervous system); the
transient clinical signs of neurotoxicity in several studies across
species; and the suggestive evidence of increased quantitative
susceptibility in the rat reproduction study.
    Since that determination, EPA has received and reviewed an
developmental neurotoxicity (DNT) study in rats, and an additional
reproduction study in rats. Taking the results of these studies into
account, as well as the rest of the data on thiamethoxam, 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 thiamethoxam is largely complete,
including acceptable/guideline developmental toxicity, 2-generation
reproduction, and DNT studies designed to detect adverse effects on the
developing organism, which could result from the mechanism that may
have produced the decreased alanine amino transferase levels. The
registrant must now submit, as a condition of registration, an
immunotoxicity study. This study is now required under 40 CFR part 158.
    The available data for thiamethoxam show the potential for
immunotoxic effects. In the subchronic dog study, leukopenia (decreased
white blood cells) was observed in females only, at the highest dose
tested (HDT) of 50 mg/kg/day; the NOAEL for this effect was 34 mg/kg/
day. The overall study NOAEL was 9.3 mg/kg/day in females (8.2 mg/kg/
day in males) based on hematology and other clinical chemistry findings
at the LOAEL of 34 mg/kg/day (32 mg/kg/day in males). In the subchronic
mouse study, decreased spleen weights were observed in females at 626
mg/kg/day; the NOAEL for this effect was the next lowest dose of 231
mg/kg/day. The overall study NOAEL was 1.4 mg/kg/day (males)

based on increased hepatocyte hypertrophy observed at the LOAEL of 14.3
mg/kg/day. The decreased absolute spleen weights were considered to be
treatment related, but were not statistically significant at 626 mg/kg/
day or at the HDT of 1,163 mg/kg/day. Since spleen weights were not
decreased relative to body weights, the absolute decreases may have
been related to the decreases in body weight gain observed at higher
doses.
    Overall, the Agency has a low concern for the potential for
immunotoxicity related to these effects for the following reasons: In
general, the Agency does not consider alterations in hematology
parameters alone to be a significant indication of potential
immunotoxicity. In the case of thiamethoxam, high-dose females in the
subchronic dog study had slight microcytic anemia as well as leukopenia
characterized by reductions in neutrophils, lymphocytes and monocytes;
the leukopenia was considered to be related to the anemic response to
exposure. Further, endpoints and doses selected for risk assessment are
protective of the observed effects on hematology. Spleen weight
decreases, while considered treatment-related, were associated with
decreases in body weight gain, and were not statistically significant.
In addition, spleen weight changes occurred only at very high doses,
more than 70 times higher than the doses selected for risk assessment.
Therefore, an additional 10X safety factor is not warranted for
thiamethoxam at this time.
    ii. For the reasons discussed in Unit III.D.2., there is low
concern for an increased susceptibility in the young.
    iii. Although there is evidence of neurotoxicity after acute
exposure to thiamethoxam at doses of 500 mg/kg/day including drooped
palpebral closure, decrease in rectal temperature and locomotor
activity and increase in forelimb grip strength, no evidence of
neuropathology was observed. These effects occurred at doses at least
fourteen-fold and 416-fold higher than the doses used for the acute,
and chronic risk assessments, respectively; thus, there is low concern
for these effects since it is expected that the doses used for
regulatory purposes would be protective of the effects noted at much
higher doses.
    iv. There are no residual uncertainties identified in the exposure
databases. The dietary food exposure assessments were performed using
tolerance-level and/or anticipated residues that are based on reliable
field trial data observed in the thiamethoxam field trials. Although
there is available information indicating that thiamethoxam and
clothianidin have different toxicological effects in mammals and should
be assessed separately, the residues of each have been combined in
these assessments to ensure that the estimated exposures of
thiamethoxam do not underestimate actual potential thiamethoxam
exposures. An assumption of 100 PCT was made for all foods evaluated in
the assessments. For the acute and chronic assessments, the EDWCs of
131.77 ppb and 11.3 ppb, respectively, were used to estimate exposure
via drinking water. Compared to the results from small-scale
prospective ground water studies where the maximum observed residue
levels from any monitoring well were 1.0 ppb for thiamethoxam and 0.73
ppb for CGA-322704, the modeled estimates are protective of what actual
exposures are likely to be. Similarly conservative Residential SOP, as
well as a chemical-specific turf transfer residue (TTR) study were used
to assess post-application exposure to children and incidental oral
exposure of toddlers. These assessments will not underestimate the
exposure and risks posed by thiamethoxam.
    b. In the final rule published in the Federal Register of February
6, 2008 (73 FR 6851) (FRL-8346-9), EPA had previously determined that
the FQPA SF for clothianidin should be retained at 10X because EPA had
required the submission of a developmental immunotoxicity study to
address the combination of evidence of decreased absolute and adjusted
organ weights of the thymus and spleen in multiple studies in the
clothianidin database, and evidence showing that juvenile rats in the
2-generation reproduction study appear to be more susceptible to these
potential immunotoxic effects. In the absence of a developmental
immunotoxicity study, EPA concluded that there was sufficient
uncertainty regarding immunotoxic effects in the young that the 10X
FQPA factor should be retained as a database uncertainty factor.
    Since that determination, EPA has received and reviewed an
acceptable/guideline developmental immunotoxicity study, which
demonstrated no treatment-related effects. Taking the results of this
study into account, as well as the rest of the data on clothianidin,
EPA has determined that reliable data show the safety of infants and
children would be adequately protected if the FQPA SF for clothianidin
were reduced to 1X. That decision is based on the following findings:
    i. The toxicity database for clothianidin is complete. As noted,
the prior data gap concerning developmental immunotoxicity has been
addressed by the submission of an acceptable developmental
immunotoxicity study.
    ii. A rat developmental neurotoxicity study is available and shows
evidence of increased quantitative susceptibility of offspring.
However, EPA considers the degree of concern for the developmental
neurotoxicity study to be low for prenatal and postnatal toxicity
because the NOAEL and LOAEL were well characterized, and the doses and
endpoints selected for risk assessment are protective of the observed
susceptibility; therefore, there are no residual concerns regarding
effects in the young.
    iii. While the rat multi-generation reproduction study showed
evidence of increased quantitative susceptibility of offspring compared
to adults, the degree of concern is low because the study NOAEL and
LOAEL have been selected for risk assessment purposes for relevant
exposure routes and durations. In addition, the potential immunotoxic
effects observed in the study have been further characterized with the
submission of a developmental immunotoxicity study that showed no
evidence of susceptibility. As a result, there are no concerns or
residual uncertainties for prenatal and postnatal toxicity after
establishing toxicity endpoints and traditional UFs to be used in the
risk assessment for clothianidin.
    iv. There are no residual uncertainties identified in the exposure
databases. The dietary food exposure assessments were performed based
on assumptions that were judged to be highly conservative and health-
protective for all durations and population subgroups, including
tolerance-level residues, adjustment factors from metabolite data,
empirical processing factors, and 100 PCT for all commodities.
Additionally, EPA made conservative (protective) assumptions in the
ground water and surface water modeling used to assess exposure to
clothianidin in drinking water. EPA used similarly conservative
assumptions to assess post-application exposure of children and adults
as well as incidental oral exposure of toddlers. These assessments will
not underestimate the exposure and risks posed by clothianidin.

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 PAD (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. Using the exposure assumptions discussed in this
unit for acute exposure, the acute dietary exposure from food and water
to thiamethoxam will occupy 9.5% of the aPAD for children 1 to 2 years
old, the population group receiving the greatest exposure. Acute
dietary exposure from food and water to clothianidin is estimated to
occupy 23% of the aPAD for children 1 to 2 years old, the population
group receiving the greatest exposure.
    2. Chronic risk. Using the exposure assumptions described in this
unit for chronic exposure, EPA has concluded that chronic exposure to
thiamethoxam from food and water will utilize 42% of the cPAD for
children 1 to 2 years old, the population group receiving the greatest
exposure. Chronic exposure to clothianidin from food and water will
utilize 19% of the cPAD for children 1 to 2 years old, the population
group receiving the greatest exposure. Based on the explanation in Unit
III.C.3., regarding residential use patterns, chronic residential
exposure to residues of thiamethoxam and clothianidin is not expected.
    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).
    Thiamethoxam is currently registered 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 thiamethoxam.
    Using the exposure assumptions described in this unit for short-
term exposures, EPA has concluded the combined short-term food, water,
and residential exposures for thiamethoxam result in aggregate MOEs of:
380 for the general U.S. population; 500 for all infants (<1 year); 440
for children 1 to 2 years; 460 for children 3-5 years; 370 for children
6-12 years; 380 for youth 13-19 years, adults 20-49 years, adults 50+
years, and females 13-49 years. Because EPA's level of concern for
thiamethoxam is a MOE of 100 or below, these MOEs are not of concern.
    Using the exposure assumptions described in this unit for short-
term exposures, EPA has concluded the combined short-term food, water,
and residential exposures for clothianidin result in aggregate MOEs of
1,700 for the general U.S. population; 480 for all infants (<1 year);
380 for children 1 to 2 years; 500 for children 3-5 years; 1,400 for
children 6-12 years; 2,200 for youth 13-19 years, adults 20-49 years,
and females 13-49 years; 2,100 for adults 50+ years. Because EPA's
level of concern for clothianidin is a MOE of 100 or below, these MOEs
are not of concern.
    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).
    Thiamethoxam is currently registered for uses that could result in
intermediate-term residential exposure, and the Agency has determined
that it is appropriate to aggregate chronic exposure through food and
water with intermediate-term residential exposures to thiamethoxam.
    Using the exposure assumptions described in this unit for
intermediate-term exposures, EPA has concluded that the combined
intermediate-term food, water, and residential exposures result in
aggregate MOEs of 380 for the general U.S. population; 540 for all
infants (<1 year); 480 for children 1 to 2 years; 500 for children 3-5
years; 370 for children 6-12 years; 380 for youth 13-19 years, adults
20-49 years, adults 50+ years, and females 13-49 years. Because EPA's
level of concern for thiamethoxam is a MOE of 100 or below, these MOEs
are not of concern.
    Using the exposure assumptions described in this unit for short-
term exposures, EPA has concluded the combined short-term food, water,
and residential exposures for clothianidin result in aggregate MOEs of
1,700 for the general U.S. population; 480 for all infants (<1 year);
380 for children 1 to 2 years; 500 for children 3-5 years; 1,400 for
children 6-12 years; 2,200 for youth 13-19 years, adults 20-49 years,
and females 13-49 years; 2,100 for adults 50+ years. Because EPA's
level of concern for clothianidin is a MOE of 100 or below, these MOEs
are not of concern.
    5. Aggregate cancer risk for U.S. population. The Agency has
classified thiamethoxam as not likely to be a human carcinogen based on
convincing evidence that a non-genotoxic mode of action for liver
tumors was established in the mouse and that the carcinogenic effects
are a result of a mode of action dependent on sufficient amounts of a
hepatotoxic metabolite produced persistently. Therefore, thiamethoxam
is not expected to pose a cancer risk.
    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 thiamethoxam or clothianidin residues.

IV. Other Considerations

A. Analytical Enforcement Methodology

    Adequate enforcement methodology (high-performance liquid
chromatography/ultraviolet (HPLC/UV) or mass spectrometry (MS)) 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:<PHONE_NUMBER>; e-mail address:
<EMAIL_ADDRESS>    For further details, refer to the document ``Thiamethoxam. Petition
to Establish a Permanent Tolerance for Residues of the Insecticide
Resulting from Food/Feed Use as a Seed Treatment on Bulb Onions.
Response to Data Gaps from Conditional Registration of Various Food/
Feed Crops (as Specified in HED Memo D281702; M. Doherty; 17 April
2007). Summary of Analytical Chemistry and Residue Data,'' available in
the docket EPA-HQ-OPP-2009-0737, at http:// www.regulations.gov.

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 a MRL for thiamethoxam.

V. Conclusion

    Therefore, tolerances are established for residues of thiamethoxam
(3-[(2-chloro-5-thiazolyl)methyl]tetrahydro-5-

methyl-N-nitro-4H-1,3,5-oxadiazin-4-imine) and its metabolite CGA-
322704 [N-(2-chloro-thiazol-5-ylmethyl)-N'-methyl-N'-nitro-guanidine],
in or on onion, dry bulb at 0.03 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: June 14, 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 180.565 is amended by alphabetically adding the following
commodity to the table in paragraph (a) to read as follows:

Sec.  180.565  Thiamethoxam; tolerances for residues.

    (a) * * *

----------------------------------------------------------------------------------------------------------------
                       Commodity                                            Parts per million
----------------------------------------------------------------------------------------------------------------
                                                    * * * * *
Onion, dry bulb.......................................                                                      0.03
                                                    * * * * *
----------------------------------------------------------------------------------------------------------------

* * * * *
[FR Doc. 2010-15035 Filed 6-22-10; 8:45 am]
BILLING CODE 6560-50-S


[Federal Register Volume 76, Number 176 (Monday, September 12, 2011)]
[Notices]
[Pages 56210-56211]
[FR Doc No: 2011-23213]

-----------------------------------------------------------------------

DEPARTMENT OF HOMELAND SECURITY

Federal Emergency Management Agency

[Internal Agency Docket No. FEMA-3331-EM; Docket ID FEMA-2011-0001]

Connecticut; Amendment No. 1 to Notice of an Emergency
Declaration

AGENCY: Federal Emergency Management Agency, DHS.

ACTION: Notice.

-----------------------------------------------------------------------

SUMMARY: This notice amends the notice of an emergency declaration for
the State of Connecticut (FEMA-3331-EM), dated August 27, 2011, and
related determinations.

DATES: Effective Date: September 2, 2011.

FOR FURTHER INFORMATION CONTACT: Peggy Miller, Office of Response and
Recovery, Federal Emergency Management Agency, 500 C Street, SW.,
Washington, DC 20472,<PHONE_NUMBER>.

SUPPLEMENTARY INFORMATION: The notice of an emergency declaration for
the State of Connecticut is hereby amended to include the Individuals
and Households Program under Section 408 of the Stafford Act, 42 U.S.C.
5174, in the following areas among those areas determined to have been
adversely affected by the event declared an emergency by the President
in his declaration of August 27, 2011.

    The counties of Fairfield, Hartford, Litchfield, Middlesex, New
Haven, New Tolland, Tolland and Windham for the Individuals and
Households Program under Section 408 of the Stafford Act, 42 U.S.C.
5174 (already designated for emergency protective measures [Category
B], including direct federal assistance, under the Public Assistance
program).

(The following Catalog of Federal Domestic Assistance Numbers (CFDA)
are to be used for reporting and drawing funds: 97.030, Community
Disaster Loans; 97.031, Cora Brown Fund; 97.032, Crisis Counseling;
97.033, Disaster Legal Services; 97.034, Disaster Unemployment
Assistance (DUA); 97.046, Fire Management Assistance Grant; 97.048,
Disaster Housing Assistance to Individuals and Households In
Presidentially Declared Disaster Areas; 97.049, Presidentially
Declared Disaster Assistance--Disaster Housing Operations for
Individuals and Households; 97.050 Presidentially Declared Disaster
Assistance to Individuals and Households--Other Needs; 97.036,
Disaster Grants--Public Assistance

(Presidentially Declared Disasters); 97.039, Hazard Mitigation
Grant.)

W. Craig Fugate,
Administrator, Federal Emergency Management Agency.
[FR Doc. 2011-23213 Filed 9-9-11; 8:45 am]
BILLING CODE 9111-23-P


MEMORANDUM

Date:	December 16, 2011 Subject:	Emission Reduction Costs for Beyond-the-floor Mercury Rate for Existing Units Designed to Burn Low Rank Virgin Coal From:	Kevin Culligan, SPPD/OAQPS To:  	EPA-HQ-OAR-2009-0234

      For the final rule, EPA has recalculated the beyond the floor control costs for existing units designed to burn low rank virgin coal using a methodology similar to that used in the IPM analysis done for the MATS proposal.  In the final rule, we have not recalculated control costs based on the other methodology used in the proposal which used ACI capital and operating costs provided in the ICR.   We have not used that approach because it was based upon an assumption that all units would need to have a baghouse (also known as a fabric filter  -  FF  -  either existing or newly installed) in order to meet the MACT PM standard and that the ACI would be used with the baghouse.  EPA has considered and used additional information demonstrating that high levels of mercury removal can be achieved with injection of brominated activated carbon and the addition of a FF is not necessary.  Furthermore, based on additional analysis related to the PM standard, EPA believes that most lignite units will not need to install new FF, therefore, EPA believes a costing methodology based on this assumption would be inappropriate.       For this analysis, EPA calculated beyond-the-floor costs for mercury controls by assuming injection of brominated activated carbon at a rate of 3.0 lb/MACF for units with ESPs and injection rates of 2.0 lb/MACF for units with baghouses (also known as fabric filters).    The rate of 2.0 lb/MACF for fabric filters is consistent with the rate assumed in all other IPM analyses for this rule.  The rate of 3.0 lb/MACF for units with ESPs is lower than the rate of 5.0 lb/MACF assumed in the IPM analysis.  EPA believes that this rate is appropriate, because a higher rate would likely result in reductions beyond those needed to meet the BTF standard of 4.0 lb/TBtu.  Figure 1 in "Activated Carbon Injection for Mercury: Overview" suggests that > 90% control can be achieved at lignite-fired units at a < 2.0 lb/MACF injection rate for units with installed FF and using treated (i.e., brominated) AC.  The figure also suggests that > 90% Hg control can be achieved at lignite-fired units at < 3.0 lb/MACF injection rate for units with installed ESPs and using treated AC.  As Table 1 below shows, based on the IPM analysis, all units would need to achieve reductions of less than 90%, therefore lower assumed injection rates are appropriate.

Table 1  -  Emission Reduction Rates Required to Meet Standard of 4 lb/TBtu.

             EPA also assumed a disposal cost of $25/ton for ash comingled with activated carbon.  This cost is consistent with a range of studies.  DOE/NETL, in a recent study examining the costs of ACI, assumed total disposal costs of $17/ton for non-hazardous fly ash. They assumed $35/ton for fly ash that would have otherwise been sold for beneficial reuse (lost revenue of $18/ton plus disposal costs of $17/ton for non-hazardous fly ash).  In an EPA study, $25 - $30 per ton were assumed as total disposal costs.               EPA recently modeled site-specific disposal costs for the RIA for the proposed rule regulating coal combustion residuals (CCRs), including fly ash.  Those costs were examined for units burning low rank virgin coal.  The disposal costs varied by state/region.  For Texas the incremental costs attributable to Hg control were $18.13/ton, while for North Dakota and Montana, the incremental costs attributable to Hg control were $32.31/ton.              Based on these key assumptions, EPA projects an average reduction cost of $27,017 per pound of Hg removed.  Unit by unit costs are provided in Table 2.

Table 2  -  Unit by unit cost estimates for achieving an emission rate of 4 lb/TBtu Hg

Plant Name Unit ID Capacity (MW) Heat Rate (Btu/kWh) Existing PM Controls (Base to Policy) Hg remv'd (lbm)  (2007$) unit  S/lbm Hg Total Cost Big Brown 1 575 11001 Cold-side ESP + Fabric Filter + SNCR -396 3954 1565723 Big Brown 2 575 10931 Cold-side ESP + Fabric Filter + SNCR -393 3980 1565723 Lewis & Clark B1 52.3 13787 Wet Scrubber -31 22920 704682 Martin Lake 1 750 11512 Cold-side ESP + Wet Scrubber -332 32175 10671737 Martin Lake 2 750 11202 Cold-side ESP + Wet Scrubber -323 32174 10383770 Martin Lake 3 750 10784 Cold-side ESP + Wet Scrubber -311 32309 10038209 Monticello 3 750 11246 Cold-side ESP + SNCR + Wet Scrubber -359 29249 10487787 R M Heskett B1 29.37 11985 Cold-side ESP -17 38871 652353 R M Heskett B2 75.5 11386 Cold-side ESP + Cyclone -22 53992 1206545 Leland Olds 1 221 11404 Cold-side ESP -109 25792 2812406 Leland Olds 2 448 11021 Cold-side ESP -217 23822 5176973 Milton R Young B1 250 10661 Cold-side ESP + SCR + Wet Scrubber -64 51542 3272935 Milton R Young B2 455 10661 Cold-side ESP + SCR + Wet Scrubber -116 49018 5665257 Stanton 1 130.3472 10990 Cold-side ESP -77 26601 2050240 Stanton 10 57.35278 10320 Fabric Filter + Dry Scrubber -31 30538 935770.1 Limestone LIM1 831 10102 Cold-side ESP + Wet Scrubber -372 29034 10797351 Limestone LIM2 858 10108 Cold-side ESP + Wet Scrubber -384 28982 11134608 Coal Creek 1 554 11219 Cold-side ESP + Wet Scrubber -162 48056 7781365 Coal Creek 2 560.3 10818 Cold-side ESP + Wet Scrubber -158 47982 7576786 Laramie River Station 1 565 11312 Cold-side ESP + Wet Scrubber -235 34742 8170580 Laramie River Station 2 570 10953 Cold-side ESP + Wet Scrubber -230 34737 7980115 Antelope Valley B1 450 10988 Fabric Filter + Dry Scrubber -264 22315 5888636 Antelope Valley B2 450 11206 Fabric Filter + Dry Scrubber -269 22269 5993120 Twin Oaks Power One U1 152 9497 Fabric Filter -50 38215 1900963 Twin Oaks Power One U2 153 10364 Fabric Filter -55 37778 2064287 Coyote B1 427 11639 Fabric Filter + Dry Scrubber -228 22122 5043515 Pirkey 1 675 10693 Cold-side ESP + Wet Scrubber -349 26185 9140141 Great River Energy Spiritwood Station 1 99 8937 Cold-side ESP + Fabric Filter + SNCR + Dry Scrubber -46 11694 535381.6 Dolet Hills 1 650 10674 Cold-side ESP + Wet Scrubber -351 27064 9500464

Total -5948

1.61E+08

Average

27016