[Federal Register Volume 78, Number 147 (Wednesday, July 31, 2013)]
[Rules and Regulations]
[Pages 46274-46279]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2013-18412]



40 CFR Part 180

[EPA-HQ-OPP-2012-0439 and EPA-HQ-OPP-2012-0514; FRL-9393-6]

Pyroxasulfone; Pesticide Tolerances

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.


SUMMARY: This regulation establishes tolerances for residues of 
pyroxasulfone in or on multiple commodities which are identified and 
discussed later in this document. K-I Chemical U.S.A., Inc. requested 
these tolerances under the Federal Food, Drug, and Cosmetic Act 

DATES: This regulation is effective July 31, 2013. Objections and 
requests for hearings must be received on or before September 30, 2013, 
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: The docket for this action, identified by docket 
identification (ID) number EPA-HQ-OPP-2012-0439 and EPA-HQ-OPP-2012-
0514, is available at http://www.regulations.gov or at the Office of 
Pesticide Programs Regulatory Public Docket (OPP Docket) in the 
Environmental Protection Agency Docket Center (EPA/DC), EPA West Bldg., 
Rm. 3334, 1301 Constitution Ave. NW., Washington, DC 20460-0001. The 
Public Reading Room is open from 8:30 a.m. to 4:30 p.m., Monday through 
Friday, excluding legal holidays. The telephone number for the Public 
Reading Room is (202) 566-1744, and the telephone number for the OPP 
Docket is (703) 305-5805. Please review the visitor instructions and 
additional information about the docket available at http://www.epa.gov/dockets.

FOR FURTHER INFORMATION CONTACT: Lois Rossi, Office of Pesticide 
Programs, Environmental Protection Agency, 1200 Pennsylvania Ave. NW., 
Washington, DC 20460-0001; telephone number: (703) 305-7090; email 
address: [email protected].


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. 
The following list of North American Industrial Classification System 
(NAICS) codes is not intended to be exhaustive, but rather provides a 
guide to help readers determine whether this document applies to them. 
Potentially affected entities may include:
     Crop production (NAICS code 111).
     Animal production (NAICS code 112).
     Food manufacturing (NAICS code 311).
     Pesticide manufacturing (NAICS code 32532).

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.ecfr.gov/cgi-bin/text-idx?&c=ecfr&tpl=/ecfrbrowse/Title40/40tab_02.tpl. To access the OCSPP 
test guidelines referenced in this document electronically, please go 
to http://www.epa.gov/ocspp and select ``Test Methods and Guidelines.''

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-2012-0439 and EPA-HQ-OPP-2012-0514 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 September 30, 2013. Addresses for mail and 
hand delivery of objections

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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 (excluding any Confidential Business Information (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 the non-CBI copy of your objection or hearing 
request, identified by docket ID number EPA-HQ-OPP-2012-0439 and EPA-
HQ-OPP-2012-0514, by one of the following methods:
     Federal eRulemaking Portal: http://www.regulations.gov. 
Follow the online instructions for submitting comments. Do not submit 
electronically any information you consider to be CBI or other 
information whose disclosure is restricted by statute.
     Mail: OPP Docket, Environmental Protection Agency Docket 
Center (EPA/DC), (28221T), 1200 Pennsylvania Ave. NW., Washington, DC 
     Hand Delivery: To make special arrangements for hand 
delivery or delivery of boxed information, please follow the 
instructions at http://www.epa.gov/dockets/contacts.htm.
    Additional instructions on commenting or visiting the docket, along 
with more information about dockets generally, is available at http://www.epa.gov/dockets.

II. Summary of Petitioned-For Tolerance

    In the Federal Register of July 25, 2012 (77 FR 43562) (FRL-9353-
6), EPA issued a document pursuant to FFDCA section 408(d)(3), 21 
U.S.C. 346a(d)(3), announcing the filing of a pesticide petition (PP 
2F8026) by K-I Chemical U.S.A., Inc. The petition requested that 40 CFR 
180.659 be amended by establishing tolerances for residues of the 
herbicide, pyroxasulfone (3-[(5-(difluoromethoxy)-1-methyl-3-
(trifluoromethyl) pyrazole-4-ylmethylsulfonyl]-4,5-dihydro-5,5-
dimethyl-1,2-oxazole), in or on wheat, grain at 0.01 parts per million 
(ppm); pyroxasulfone (3-[(5-(difluoromethoxy)-1-methyl-3-
(trifluoromethyl) pyrazole-4-ylmethylsulfonyl]-4,5-dihydro-5,5-
dimethyl-1,2-oxazole) and its metabolites M-1 (5-difluoromethoxy-1-
methyl-3-trifluoromethyl-1 H-pyrazol-4-ylmethanesulfonic acid) and M-25 
(5-difluoromethoxy-3-trifluoromethyl-1 H-pyrazol-4-yl)methanesulfonic 
acid) calculated as the stoichiometric equivalent of pyroxasulfone, in 
or on wheat, straw at 0.6 ppm; \1\ and pyroxasulfone (3-[(5-
(difluoromethoxy)-1-methyl-3-(trifluoromethyl) pyrazole-4-
ylmethylsulfonyl]-4,5-dihydro-5,5-dimethyl-1,2-oxazole) and its 
metabolites M-1 (5-difluoromethoxy-1-methyl-3-trifluoromethyl-1 H-
pyrazol-4-ylmethanesulfonic acid), M-3 (5-difluoromethoxy-1-methyl-3-
trifluoromethyl-1 H-pyrazol-4-carboxylic acid), and M-25 (5-
difluoromethoxy-3-trifluoromethyl-1 H-pyrazol-4-yl) methanesulfonic 
acid) calculated as the stoichiometric equivalent of pyroxasulfone in 
or on wheat, forage at 6.0 ppm and wheat, hay at 1.0 ppm.

    \1\ EPA's July 25, 2012 notification of the requested tolerance 
contained an error. It stated that petitioners requested a tolerance 
of the parent pyroxasulfone and the M-1 and M-25 metabolites on 
``wheat, grain at 0.6 ppm'' instead of ``wheat, straw at 0.6 ppm'' 
as the petitioners requested. To address the error and provide 
notice of requested tolerance, EPA issued a correction. See 77 FR 
59577; FRL-9364-3 (Sept. 28, 2012).

    Also, in the Federal Register of August 22, 2012 (77 FR 50661) 
(FRL-9358-9), EPA issued a document pursuant to FFDCA section 
408(d)(3), 21 U.S.C. 346a(d)(3), announcing the filing of a pesticide 
petition (PP 2F8042) by K-I Chemical U.S.A., Inc. The petition 
requested that 40 CFR 180.659 be amended by establishing tolerances for 
residues of the pyroxasulfone, (3-[(5-(difluoromethoxy)-1-methyl-3- 
(trifluoromethyl) pyrazole-4-ylmethylsulfonyl]-4,5-dihydro-5,5-
dimethyl-1,2-oxazole) and its metabolite M-3 (5-difluoromethoxy-1-
methyl-3-trifluoromethyl-1H-pyrazol-4- carboxylic acid), in or on 
cotton seed at 0.01 ppm and pyroxasulfone (3-[(5-(difluoromethoxy)-1-
methyl-3- (trifluoromethyl) pyrazole-4-ylmethylsulfonyl]-4,5-dihydro-
5,5-dimethyl-1,2-oxazole) and its metabolite M-1 (5-difluoromethoxy-1-
methyl-3-trifluoromethyl-1H-pyrazol-4- ylmethanesulfonic acid 
calculated as the stoichiometric equivalent of pyroxasulfone in or on 
cotton, gin byproducts at 0.2 ppm.
    These documents referenced a summary of the petition prepared by 
K.I. Chemical U.S.A., Inc. the registrant, c/o Landis International, 
Inc., which is available in the associated dockets, http://www.regulations.gov. There were no comments received in response to 
either of these notices of filing.
    Based upon review of the data supporting the petition, EPA has 
increased the proposed tolerances for wheat, grain and cotton, 
undelinted seed and established a tolerance for milk. The reason for 
these changes are explained in Unit IV.C.

III. Aggregate Risk Assessment and Determination of Safety

    Section 408(b)(2)(A)(i) of FFDCA allows EPA to establish a 
tolerance (the legal limit for a pesticide chemical residue in or on a 
food) only if EPA determines that the tolerance is ``safe.'' Section 
408(b)(2)(A)(ii) of FFDCA defines ``safe'' to mean that ``there is a 
reasonable certainty that no harm will result from aggregate exposure 
to the pesticide chemical residue, including all anticipated dietary 
exposures and all other exposures for which there is reliable 
information.'' This includes exposure through drinking water and in 
residential settings, but does not include occupational exposure. 
Section 408(b)(2)(C) of FFDCA requires EPA to give special 
consideration to exposure of infants and children to the pesticide 
chemical residue in establishing a tolerance and to ``ensure that there 
is a reasonable certainty that no harm will result to infants and 
children from aggregate exposure to the pesticide chemical residue. . . 
    Consistent with FFDCA section 408(b)(2)(D), and the factors 
specified in FFDCA section 408(b)(2)(D), 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 pyroxasulfone including 
exposure resulting from the tolerances established by this action. 
EPA's assessment of exposures and risks associated with pyroxasulfone 

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. Pyroxasulfone acute toxicity to mammals is low by all routes 
of exposure. Subchronic and chronic oral toxicity testing of 
pyroxasulfone in mice, rats, and dogs produced a variety of adverse 
effects in several target organs. Effects seen in animal studies 
included cardiac toxicity (increased cardiomyopathy in mice and rats), 
liver toxicity (centrilobular hepatocellular hypertrophy, 
histopathological, and/or clinical pathological indicators), 
neurotoxicity characterized by axonal/myelin degeneration in the 
sciatic nerve (dog, mouse, and rat) and spinal cord sections (dog), 
skeletal muscle myopathy, kidney

[[Page 46276]]

toxicity (increased incidence of chronic progressive nephropathy in 
dogs and retrograde nephropathy in mice), urinary bladder mucosal 
hyperplasia, inflammation, and urinary bladder transitional cell 
papillomas (rats). Decreased body weight and enzyme changes were noted 
in some studies. Immunotoxicity studies in rats and mice showed no 
evidence of immunotoxic effects from pyroxasulfone. Pyroxasulfone was 
moderately toxic to rats following a 4-week dermal exposure producing 
local inflammation and systemic effects of minimal to mild cardiac 
myofiber degeneration at the limit dose. No adverse effects were noted 
in a 28-day inhalation study at the highest-dose tested. Pyroxasulfone 
did not exhibit developmental toxicity in the rat and exhibited only 
slight developmental toxicity in rabbits (reduced fetal weight and 
resorptions) at the limit dose. However, developmental effects were 
noted in post-natal day (PND) 21 offspring in the rat developmental 
neurotoxicity (DNT) study characterized as decreased brain weight and 
morphometric changes. Developmental effects in the rabbit developmental 
study and DNT study occurred in the absence of maternal toxicity, 
indicating potential increased quantitative susceptibility of 
offspring. In a reproductive toxicity in rats reduced pup weight and 
body weight gains during lactation occurred at similar or higher doses 
causing pronounced maternal toxicity (reduced body weight, body weight 
gain, and food consumption and increased kidney weight, cardiomyopathy, 
and urinary bladder mucosal hyperplasia with inflammation). In cancer 
studies in mice and rats, renal tubular adenomas were observed in male 
mice and urinary bladder transitional cell papillomas were observed in 
male rats. The kidney adenomas in male mice were determined to be 
spontaneous and not treatment-related based on the following 
    1. Absence of any cytotoxicity (degeneration or individual cell 
necrosis) in studies ranging from 14 days to 18 months at doses up to 
15,000 ppm.
    2. Absence of cell regeneration leading to precursor lesions such 
as atypical tubular hyperplasia at all time points and doses up to 
15,000 ppm.
    3. Lack of exacerbation of chronic progressive nephropathy, a 
spontaneous disease in rodents that results in cell regeneration which 
can result in renal tubule tumors in chronic studies.
    4. Lack of a clear dose response in the distribution of tumors 
between test substance treated groups.

The urinary bladder tumors seen in male rats were determined to be a 
threshold effect. Pyroxasulfone exposure causes the growth of crystals 
in the urinary tract with subsequent calculi formation resulting in 
cellular damage. Crystal formation in the absence of calculi is not 
associated with hyperplasia or urinary bladder tumors; therefore, the 
formation of urinary bladder calculi is the prerequisite for subsequent 
hyperplasia and neoplasia. In other words, urinary bladder tumors do 
not develop at doses too low to produce calculi. There is also a clear 
threshold of 1,000 ppm (42.55 milligrams/kilogram/day (mg/kg/day)) for 
development of calculi and tumorigenesis. The point of departure (POD) 
of 50 ppm (2.0 mg/kg/day) selected for chronic risk assessment is not 
expected to result in urinary bladder calculi formation, which is a 
prerequisite for subsequent hyperplasia and neoplasia. Therefore, the 
Agency has determined that the quantification of risk using a non-
linear approach (i.e., Reference dose (RfD)) will adequately account 
for all chronic toxicity, including carcinogenicity, that could result 
from exposure to pyroxasulfone. There is no concern for mutagenicity.
    Specific information on the studies received and the nature of the 
adverse effects caused by pyroxasulfone as well as the no-observed-
adverse-effect-level (NOAEL) and the lowest-observed-adverse-effect-
level (LOAEL) from the toxicity studies can be found at http://www.regulations.gov in document ``Pyroxasulfone Human Health Risk 
Assessment for Use of Pyroxasulfone on Wheat and Cotton,'' p. 36 in 
docket ID numbers EPA-HQ-OPP-2012-0439 and EPA-HQ-OPP-2012-0514.

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 pyroxasulfone used for 
human risk assessment is discussed in Unit III.B. of the final rule 
published in the Federal Register of February 29, 2012 (77 FR 12207) 

C. Exposure Assessment

    1. Dietary exposure from food and feed uses. In evaluating dietary 
exposure to pyroxasulfone, EPA considered exposure under the 
petitioned-for tolerances as well as all existing pyroxasulfone 
tolerances in 40 CFR 180.659. EPA assessed dietary exposures from 
pyroxasulfone 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. Such effects were identified 
for pyroxasulfone. In estimating acute dietary exposure, EPA used food 
consumption information from the U.S. Department of Agriculture's 
National Health and Nutrition Examination Survey, What We Eat in 
America, (NHANES/WWEIA). As to residue levels in food, EPA assumed 100 
percent crop treated (PCT) at tolerance-level residues adjusted upward 
to account for metabolites which are not in the tolerance expression 
from specific use patterns.
    ii. Chronic exposure. In conducting the chronic dietary exposure 
assessment EPA used the food consumption data from the U.S. Department 
of Agriculture's NHANES/WWEIA. As to residue levels in food, EPA made 
the same assumptions (adjusted tolerance-level residues and 100 PCT) as 
in the acute dietary exposure assessment.
    iii. Cancer. EPA determines whether quantitative cancer exposure 
and risk assessments are appropriate for a food-use pesticide based on 
the weight of the evidence from cancer studies and other relevant data. 
Cancer risk is quantified using a linear or nonlinear approach. If 
sufficient information on the carcinogenic mode of action is available,

[[Page 46277]]

a threshold or nonlinear approach is used and a cancer RfD is 
calculated based on an earlier noncancer key event. If carcinogenic 
mode of action data are not available, or if the mode of action data 
determines a mutagenic mode of action, a default linear cancer slope 
factor approach is utilized. Based on the data summarized in Unit 
III.A., EPA has concluded that a nonlinear RfD approach is appropriate 
for assessing cancer risk to pyroxasulfone. Cancer risk was assessed 
using the same exposure estimates as discussed in Unit III.C.1.ii.
    iv. Anticipated residue and PCT information. EPA did not use 
anticipated residue and/or PCT information in the dietary assessment 
for pyroxasulfone. Adjusted tolerance level residues and/or 100 PCT 
were assumed for all food commodities.
    2. Dietary exposure from drinking water. The Agency used screening 
level water exposure models in the dietary exposure analysis and risk 
assessment for pyroxasulfone in drinking water. These simulation models 
take into account data on the physical, chemical, and fate/transport 
characteristics of pyroxasulfone. Further information regarding EPA 
drinking water models used in pesticide exposure assessment can be 
found at http://www.epa.gov/oppefed1/models/water/index.htm.
    Based on the Pesticide Root Zone Model/Exposure Analysis Modeling 
System (PRZM/EXAMS) and Pesticide Root Zone Model Ground Water (PRZM 
GW), the estimated drinking water concentrations (EDWCs) of 
pyroxasulfone for acute exposures are estimated to be 17 parts per 
billion (ppb) for surface water and 210 ppb for ground water. EDWCs of 
pyroxasulfone for chronic exposures for non-cancer assessments are 
estimated to be 3.2 ppb for surface water and 174 ppb for ground water.
    Modeled estimates of drinking water concentrations were directly 
entered into the dietary exposure model. For acute dietary risk 
assessment, the water concentration value of 210 ppb was used to assess 
the contribution to drinking water. For chronic dietary risk 
assessment, the water concentration of value 174 ppb was used to assess 
the contribution to drinking water.
    3. From non-dietary exposure. The term ``residential exposure'' is 
used in this document to refer to non-occupational, non-dietary 
exposure (e.g., for lawn and garden pest control, indoor pest control, 
termiticides, and flea and tick control on pets). Pyroxasulfone is not 
registered for any specific use patterns that would result in 
residential exposure.
    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 
pyroxasulfone to share a common mechanism of toxicity with any other 
substances, and pyroxasulfone does not appear to produce a toxic 
metabolite produced by other substances. For the purposes of this 
tolerance action, therefore, EPA has assumed that pyroxasulfone 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 Web site 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 
    2. Prenatal and postnatal sensitivity. The pre-natal and post-natal 
toxicity database for pyroxasulfone includes developmental toxicity 
studies in rats and rabbits, a DNT study in rats, and a 2-generation 
reproduction toxicity study in rats. As discussed in Unit III.A., 
evidence of increased susceptibility of fetuses and offspring was seen 
in the DNT study and developmental toxicity study in rabbits following 
in utero or post-natal exposure to pyroxasulfone. No increased 
susceptibility was seen in the rat developmental or reproduction 
toxicity studies. In rabbits, developmental toxicity was only seen at 
the limit dose of 1,000 mg/kg/day as reduced fetal weight and increased 
fetal resorptions with a NOAEL of 500 mg/kg/day for these effects, 
compared to no maternal toxicity at these doses. In a DNT study in 
rats, offspring toxicity (decreased brain weight and morphometric 
changes on PND 21) was seen at 300 mg/kg/day compared to no maternal 
toxicity at 900 mg/kg/day. The degree of concern for the increased 
susceptibility seen in these studies is low and there are no residual 
uncertainties based on the following considerations:
    i. The increased susceptibility is occurring at high doses.
    ii. NOAELs and LOAELs have been identified for all effects of 
concern, and thus a clear dose response has been well defined.
    iii. The PODs selected for risk assessment are protective of the 
fetal/offspring effects.
    3. Conclusion. EPA has determined that reliable data show the 
safety of infants and children would be adequately protected if the 
FQPA SF were reduced to 1x. That decision is based on the following:
    i. The toxicity database for pyroxasulfone is complete.
    ii. Pyroxasulfone is a neurotoxic chemical and there is evidence of 
increased susceptibility of offspring with regard to neurotoxic effects 
in the rat DNT study. There is also evidence of increased 
susceptibility of fetuses/offspring with regard to non-neurotoxic 
effects in the rabbit developmental toxicity study. However, the 
concern for the increased susceptibility is low for the reasons stated 
in Unit III.D.2.; therefore, EPA determined that a 10X FQPA safety 
factor is not necessary to protect infants and children.
    iii. There are no residual uncertainties identified in the exposure 
databases. The dietary food exposure assessments were performed based 
on 100 PCT and adjusted tolerance-level residues. EPA made conservative 
(protective) assumptions in the ground and surface water modeling used 
to assess exposure to pyroxasulfone in drinking water. These 
assessments will not underestimate the exposure and risks posed by 

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-, intermediate-, and chronic-term 
risks are evaluated by comparing the estimated aggregate food, water, 
and residential exposure to the appropriate

[[Page 46278]]

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 pyroxasulfone will occupy 3.6% of the aPAD for all infants (< 1-
year-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 
pyroxasulfone from food and water will utilize 48% of the cPAD for all 
infants (< 1-year-old) the population group receiving the greatest 
exposure. There are no residential uses for pyroxasulfone.
    3. Short- and intermediate-term risk. Short- and intermediate-term 
aggregate exposure takes into account short- and intermediate-term 
residential exposure plus chronic exposure to food and water 
(considered to be a background exposure level). Short- and 
intermediate-term adverse effects were identified; however, 
pyroxasulfone is not registered for any use patterns that would result 
in short- or intermediate-term residential exposure. Because there is 
no short- or intermediate-term residential exposure and chronic dietary 
exposure has already been assessed under the appropriately protective 
cPAD (which is at least as protective as the POD used to assess short- 
and intermediate-term risk), no further assessment of short- or 
intermediate-term risk is necessary, and EPA relies on the chronic 
dietary risk assessment for evaluating short- and intermediate-term 
risk for pyroxasulfone.
    4. Aggregate cancer risk for U.S. population. As explained in Unit 
III.A., the Agency has determined that the quantification of risk using 
a non-linear (i.e., RfD) approach will adequately account for all 
chronic toxicity, including carcinogenicity, that could result from 
exposure to pyroxasulfone. Therefore, based on the results of the 
chronic risk assessment discussed in Unit III.E.2., pyroxasulfone 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 pyroxasulfone residues.

IV. Other Considerations

A. Analytical Enforcement Methodology

    Adequate enforcement methodology (a liquid chromatography/mass 
spectrometry/mass spectrometry (LC/MS/MS) method) is available to 
enforce the tolerance expression. The method may be requested from: 
Chief, Analytical Chemistry Branch, Environmental Science Center, 701 
Mapes Rd., Ft. Meade, MD 20755-5350; telephone number: (410) 305-2905; 
email address: [email protected].

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 United Nations 
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 pyroxasulfone.

C. Revisions to Petitioned-For Tolerances

    EPA has increased the proposed tolerance levels for wheat, grain 
from 0.01 ppm to 0.03 ppm and cotton, undelinted seed from 0.01 ppm to 
0.04 ppm. The increase in these two tolerance levels are due to the use 
of the Organization for Economic Cooperation and Development tolerance 
calculation procedures, inclusion of different metabolites of concern, 
significant figures, and use of all residue field trials. The proposed 
commodity term, ``cotton, seed'' is being revised to ``cotton, 
undelinted seed.''
    Additionally, EPA is establishing a tolerance for pyroxasulfone in 
milk as a result of the increased livestock burden from use of 
pyroxasulfone on wheat and cotton commodities.

V. Conclusion

    Therefore, tolerances are established for residues of 
pyroxasulfone, 3-[[[5-(difluoromethoxy)-1-methyl-3-(trifluoromethyl)-
including its metabolites and degradates, as set forth in the 
regulatory text.

VI. Statutory and Executive Order Reviews

    This final rule establishes tolerances under FFDCA section 408(d) 
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 FFDCA section 408(d), 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 FFDCA section 408(n)(4). 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

[[Page 46279]]

unfunded mandate as described under Title II of the Unfunded Mandates 
Reform Act of 1995 (UMRA) (2 U.S.C. 1501 et seq.).
    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) (15 U.S.C. 272 note).

VII. Congressional Review Act

    Pursuant to the Congressional Review Act (5 U.S.C. 801 et seq.), 
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 
the rule in the Federal Register. This action 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: July 25, 2013.
Lois Rossi,
Director, Registration Division, Office of Pesticide Programs.

    Therefore, 40 CFR chapter I is amended as follows:


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

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

2. Section 180.659 is amend by:
i. Adding alphabetically the following commodities to the table in 
paragraph (a)(1);
ii. Adding alphabetically the following commodities to the table in 
paragraph (a)(2); and
iii. Adding paragraph (a)(4).
    The additions read as follows:

Sec.  180.659  Pyroxasulfone; tolerances for residues.

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

                                                               Parts per
                          Commodity                             million
                                * * * * *
Cotton, undelinted seed.....................................        0.04
Wheat, grain................................................        0.03

    (2) * * *

                                                              Parts per
                         Commodity                             million
Cotton, gin byproducts.....................................         0.20
                                * * * * *
Wheat, forage..............................................         6.0
Wheat, hay.................................................         1.0
Wheat, straw...............................................         0.60

* * * * *
    (4) Tolerances are established for residues of the herbicide 
pyroxasulfone, including its metabolites and degradates, in or on the 
commodities in the following table. Compliance with the tolerance 
levels specified in the following table is to be determined by 
measuring only the sum of pyroxasulfone [3-[[[5-(difluoromethoxy)-1-
dihydro-5,5-dimethylisoxazole] and its metabolites [5-
yl]methanesulfonic acid (M-1) and 5-(difluoromethoxy)-1-methyl-3-
(trifluoromethyl)-1H-pyrazol-4-carboxylic acid (M-3), calculated as the 
stoichiometric equivalent of pyroxasulfone, in or on the commodity.

                                                              Parts per
                         Commodity                             million
Milk.......................................................       0.003

* * * * *
[FR Doc. 2013-18412 Filed 7-30-13; 8:45 am]