sethoxydim (Poast) Pesticide Petition Filing Notice 8/02
ENVIRONMENTAL PROTECTION AGENCY
Notice of Filing a Pesticide Petition To Establish a Tolerance
for a Certain Pesticide Chemical in or on Food
AGENCY: Environmental Protection Agency (EPA).
SUMMARY: This notice announces the initial filing of a pesticide
petition proposing the establishment of regulations for residues of a
certain pesticide chemical in or on various food commodities.
DATES: Comments, identified by docket ID number OPP-2002-0236 must be
received on or before October 11, 2002.
ADDRESSES: Comments may be submitted by mail, electronically, or in
person. Please follow the detailed instructions for each method as
provided in Unit I.C. of the SUPPLEMENTARY INFORMATION. To ensure
proper receipt by EPA, it is imperative that you identify docket ID
number OPP-2002-0236 in the subject line on the first page of your
FOR FURTHER INFORMATION CONTACT: By mail: Jim Tompkins, Registration
Division (7505C), Office of Pesticide Programs, Environmental
Protection Agency, 1200 Pennsylvania Ave., NW., Washington, DC 20460;
telephone number: (703) 305-5704; and e-mail address:
I. General Information
A. Does This Action Apply to Me?
You may be affected by this action if you are an agricultural
producer, food manufacturer or pesticide manufacturer. Potentially
affected categories and entities may include, but are not limited to:
Categories NAICS codes potentially
Industry 111 Crop production
112 Animal production
311 Food manufacturing
This listing is not intended to be exhaustive, but rather provides
a guide for readers regarding entities likely to be affected by this
action. Other types of entities not listed in the table could also be
affected. The North American Industrial Classification System (NAICS)
codes have been provided to assist you and others in determining
whether or not this action might apply to certain entities. If you have
questions regarding the applicability of this action to a particular
entity, consult the person listed under FOR FURTHER INFORMATION
B. How Can I Get Additional Information, Including Copies of This
Document and Other Related Documents?
1. Electronically. You may obtain electronic copies of this
document, and certain other related documents that might be available
electronically, from the EPA Internet Home Page at http://www.epa.gov/.
To access this document, on the Home Page select ``Laws and
Regulations'' and then look up the entry for this document under the
``Federal Register--Environmental Documents.'' You can also go directly
to the Federal Register listings at http://www.epa.gov/fedrgstr/.
2. In person. The Agency has established an official record for
this action under docket ID number OPP-2002-0236. The official record
consists of the documents specifically referenced in this action, any
public comments received during an applicable comment period, and other
information related to this action, including any information claimed
as confidential business information (CBI). This official record
includes the documents that are physically located in the docket, as
well as the documents that are referenced in those documents. The
public version of the official record does not include any information
claimed as CBI. The public version of the official record, which
includes printed, paper versions of any electronic comments submitted
during an applicable comment period, is available for inspection in the
Public Information and Records Integrity Branch (PIRIB), Rm. 119,
Crystal Mall #2, 1921 Jefferson Davis Highway, Arlington, VA,
from 8:30 a.m. to 4 p.m., Monday through Friday, excluding legal
holidays. The PIRIB telephone number is (703) 305-5805.
C. How and to Whom Do I Submit Comments?
You may submit comments through the mail, in person, or
electronically. To ensure proper receipt by EPA, it is imperative that
you identify docket ID number OPP-2002-0236 in the subject line on the
first page of your response.
1. By mail. Submit your comments to: Public Information and Records
Integrity Branch (PIRIB), Information Resources and Services Division
(7502C), Office of Pesticide Programs (OPP), Environmental Protection
Agency, 1200 Pennsylvania Ave., NW., Washington, DC 20460.
2. In person or by courier. Deliver your comments to: Public
Information and Records Integrity Branch (PIRIB), Information Resources
and Services Division (7502C), Office of Pesticide Programs (OPP),
Environmental Protection Agency, Rm. 119, Crystal Mall #2, 1921
Jefferson Davis Highway, Arlington, VA. The PIRIB is open from 8:30
a.m. to 4 p.m., Monday through Friday, excluding legal holidays. The
PIRIB telephone number is (703) 305-5805.
3. Electronically. You may submit your comments electronically by
e-mail to: firstname.lastname@example.org, or you can submit a computer disk as
described above. Do not submit any information electronically that you
consider to be CBI. Avoid the use of special characters and any form of
encryption. Electronic submissions will be accepted in Wordperfect 6.1/
8.0 or ASCII file format. All comments in electronic form must be
identified by docket ID number OPP-2002-0236. Electronic comments may
also be filed online at many Federal Depository Libraries.
D. How Should I Handle CBI That I Want To Submit to the Agency?
Do not submit any information electronically that you consider to
be CBI. You may claim information that you submit to EPA in response to
this document as CBI by marking any part or all of that information as
CBI. Information so marked will not be disclosed except in accordance
with procedures set forth in 40 CFR part 2. In addition to one complete
version of the comment that includes any information claimed as CBI, a
copy of the comment that does not contain the information claimed as
CBI must be submitted for inclusion in the public version of the
official record. Information not marked confidential will be included
in the public version of the official record without prior notice. If
you have any questions about CBI or the procedures for claiming CBI,
please consult the person identified under FOR FURTHER INFORMATION
E. What Should I Consider as I Prepare My Comments for EPA?
You may find the following suggestions helpful for preparing your
1. Explain your views as clearly as possible.
2. Describe any assumptions that you used.
3. Provide copies of any technical information and/or data you used
that support your views.
4. If you estimate potential burden or costs, explain how you
arrived at the estimate that you provide.
5. Provide specific examples to illustrate your concerns.
6. Make sure to submit your comments by the deadline in this
7. To ensure proper receipt by EPA, be sure to identify the docket
ID number assigned to this action in the subject line on the first page
of your response. You may also provide the name, date, and Federal
II. What Action Is the Agency Taking?
EPA has received a pesticide petition as follows proposing the
establishment and/or amendment of regulations for residues of a certain
pesticide chemical in or on various food commodities under section 408
of the Federal Food, Drug, and Cosmetic Act (FFDCA), 21 U.S.C. 346a.
EPA has determined that this petition contains data or information
regarding the elements set forth in section 408(d)(2); however, EPA has
not fully evaluated the sufficiency of the submitted data at this time
or whether the data support granting of the petition. Additional data
may be needed before EPA rules on the petition.
List of Subjects
Environmental protection, Agricultural commodities, Feed additives,
Food additives, Pesticides and pests, Reporting and recordkeeping
Dated: August 30, 2002.
Acting Director, Registration Division, Office of Pesticide Programs.
Summary of Petition
The petitioner summary of the pesticide petition is printed below
as required by section 408(d)(3) of the
FFDCA. The summary of the petition was prepared by the petitioner and
represents the view of the petitioner. EPA is publishing the petition
summary verbatim without editing it in any way. The petition summary
announces the availability of a description of the analytical methods
available to EPA for the detection and measurement of the pesticide
chemical residues or an explanation of why no such method is needed.
EPA has received a pesticide petition (2F4075) from BASF
Corporation, P.O. Box 13528, Research Triangle Park, NC 27709-3528
proposing, pursuant to section 408(d) of the Federal Food, Drug, and
Cosmetic Act (FFDCA), 21 U.S.C. 346a(d), to amend 40 CFR part 180 by
establishing a tolerance for residues of sethoxydim, 2-[1-
one and its metabolites containing the 2-cyclohexen-1-one moiety
(calculated as the herbicide) in or on the raw agricultural commodity
(RAC) corn, sweet (K+CHR at 0.4 part per million (ppm); corn, sweet,
forage at 3.0 ppm; corn, sweet, stover at 3.5 ppm; milk at 0.5 ppm;
cattle, meat byproduct, at 1.0 ppm; goat, meat byproduct at 1.0 ppm;
hog, meat byproduct at 1.0 ppm; horse, meat byproduct at 1.0 ppm; and
sheep, meat by product at 1.0 ppm. EPA has determined that the petition
contains data or information regarding the elements set forth in
section 408(d)(2) of the FFDCA; however, EPA has not fully evaluated
the sufficiency of the submitted data at this time or whether the data
support granting of the petition. Additional data may be needed before
EPA rules on the petition.
A. Residue Chemistry
1. Plant metabolism. The qualitative nature of the residues in
plants and animals is adequately understood for the purposes of
2. Analytical method. Analytical methods for detecting levels of
sethoxydim and its metabolites in or on food with a limit of detection
that allows monitoring of food with residues at or above the levels set
in these tolerances were submitted to EPA. The proposed analytical
method involves extraction, partition, and clean-up. Samples are then
analyzed by gas chromatography with sulfur-specific flame photometric
detection. The limit of quantitation is 0.05 ppm.
3. Magnitude of residues. Sweet corn at 14 locations throughout the
major sweet corn-growing regions of the United States were treated with
Poast herbicide, in order to determine the magnitude of the residue in
or on sweet corn RAC samples. The applications were applied over the
top of the ``sethoxydim-resistant'' hybrid corn plants at the target
rate of 0.3 pounds active ingredient per acre (lb ai/A) in two
sequential applications, for a maximum seasonal rate of 0.6 lb ai/A.
There was a 10-day target interval between applications, with the last
application occurring 30 days prior to the anticipated fresh corn
Fresh corn, forage, and stover samples were analyzed by common
moiety methods that determine both parent plus metabolites. The highest
individual total residues as parent equivalent for fresh corn, forage,
and stover were 0.36, 2.67, and 3.32 ppm, respectively. The residue
decline site showed trends in decreasing residues with increasing pre-
harvest intervals (PHI) in fresh corn and forage. There was no decline
trend for stover as residues remained somewhat consistent through the
71-91 DALA sampling.
B. Toxicological Profile
1. Acute toxicity. Based on the available acute toxicity data,
sethoxydim does not pose any acute dietary risks. A summary of the
acute toxicity studies follows:
i. Acute oral toxicity, rat. Toxicity Category III; lethal dose
(LD50) = 3,125 milligrams/kilogram (mg/kg) (male), 2,676 mg/
ii. Acute dermal toxicity, rat. Toxicity Category III;
LD50 >5,000 mg/kg (male and female).
iii. Acute inhalation toxicity, rat. Toxicity Category III; lethal
concentration (LC50) (4-hour) = 6.03 mg/L (male), 6.28 mg/L
iv. Primary eye irritation, rabbit. Toxicity Category IV; no
v. Primary dermal irritation, rabbit. Toxicity Category IV; no
vi. Dermal sensitization, guinea pig. Waived because no
sensitization was seen in guinea pigs dosed with the end-use product
Poast (18% a.i.).
2. Genotoxicity. Ames assays were negative for gene mutation in
Salmonella typhimurium strains TA98, TA100, TA1535, and TA 1537, with
and without metabolic activity.
A Chinese hamster bone marrow cytogenetic assay was negative for
structural chromosomal aberrations at doses up to 5,000 mg/kg in
Chinese hamster bone marrow cells in vivo.
Recombinant assays and forward mutations tests in Bacillus
subtilis, Escherichia coli, and S. typhimurium were all negative for
genotoxic effects at concentrations of greater than or equal to 100%.
3. Reproductive and developmental toxicity. A developmental
toxicity study in rats fed dosages of 0, 50, 180, 650, and 1,000 mg/kg/
day with a maternal no observed adverse effect level (NOAEL) of 180 mg/
kg/day and a maternal lowest observed adverse effect level (LOAEL) of
650 mg/kg/day (irregular gait, decreased activity, excessive
salivation, and anogenital staining); and a developmental NOAEL of 180
mg/kg/day, and a developmental LOAEL of 650 mg/kg/day (21 to 22%
decrease in fetal weights, filamentous tail, and lack of tail due to
the absence of sacral and/or caudal vertebrae, and delayed ossification
in the hyoids, vertebral centrum and/or transverse processes,
sternebrae and/or metatarsals, and pubes).
A developmental toxicity study in rabbits fed doses of 0, 80, 160,
320, and 400 mg/kg/day with a maternal NOAEL of 320 mg/kg/day and a
maternal LOAEL of 400 mg/kg/day (37% reduction in body weight gain
without significant differences in group mean body weights and
decreased food consumption during dosing); and a developmental NOAEL
greater than 400 mg/kg/day highest dose tested (HTD).
A 2-generation reproduction study with rats fed diets containing 0,
150, 600, and 3,000 ppm (approximately 0, 7.5, 30, and 150 mg/kg/day)
with no reproductive effects observed under the conditions of the
4. Subchronic toxicity. A 21-day dermal study in rabbits with a
(NOAEL) of >1,000 mg/kg/day (limit dose). The only dose-related finding
was slight epidermal hyperplasia at the dosing site in nearly all males
and females dosed at 1,000 mg/kg/day. This was probably an adaptive
5. Chronic toxicity. A summary of the chronic toxicity studies
i. A 1-year feeding study with dogs fed diets containing 0, 8.86/
9.41, 17.5/19.9, and 110/129 mg/kg/day (males/females) with a NOAEL of
8.86/9.41 mg/kg/day (males/females) based on equivocal anemia in male
dogs at the 17.5-mg/kg/day dose level.
ii. A 2-year chronic feeding/carcinogenicity study with mice fed
diets containing 0, 40, 120, 360, and 1,080 ppm (equivalent to 0, 6,
18, 54, and 162 mg/kg/day) with a systemic NOAEL of 120 ppm (18 mg/kg/
day) based on non-neoplastic liver lesions in male mice at the 360 ppm
(54 mg/kg/day) dose level. There were no carcinogenic effects observed
under the conditions of the study. The maximum tolerated dose (MTD) was
not achieved in female mice.
iii. A 2-year chronic feeding/carcinogenic study with rats fed
diets containing 0, 2, 6, and 18 mg/kg/day with a systemic NOAEL
greater than or equal to 18 mg/kg/day HDT. There were no carcinogenic
effects observed under the conditions of the study. This study was
reviewed under current guidelines and was found to be unacceptable
because the doses used were insufficient to induce a toxic response and
an MTD was not achieved.
iv. A second chronic feeding/carcinogenic study with rats fed diets
containing 0, 360, and 1,080 ppm (equivalent to 18.2/23.0, and 55.9/
71.8 mg/kg/day (males/females). The dose levels were too low to elicit
a toxic response in the test animals and failed to achieve an MTD or
define a LOAEL. Slight decreases in body weight in rats at the 1,080
ppm dose level, although not biologically significant, support a free-
standing NOAEL of 1,080 ppm (55.9/71.8 mg/kg/day (males/females)).
There were no carcinogenic effects observed under the conditions of the
6. Animal metabolism. In a rat metabolism study, excretion was
extremely rapid and tissue accumulation was negligible.
7. Metabolite toxicology. As a condition to registration, BASF had
been asked to submit additional toxicology studies for the hydroxy-
metabolites of sethoxydim. EPA agreed with BASF's recommendation to use
the most abundant metabolite, 5-OH-MSO2, as surrogate for all
metabolites. Based on these data, it was concluded that the
toxicological potency of the plant hydroxy-metabolites is likely to be
equal or less than that of the parent compound. The tolerance
expression for sethoxydim and its metabolites containing the 2-
cyclohexen-1-one moiety, measured as parent. Hence, the hydroxy-
metabolites are figured into all tolerance calculations.
8. Endocrine disruption. No specific tests have been performed with
sethoxydim to determine whether the chemical may have an effect in
humans that is similar to an effect produced by naturally-occurring
estrogen or other endocrine effects.
C. Aggregate Exposure
1. Dietary exposure. For purposes of assessing the potential
dietary exposure, BASF has estimated aggregate exposure based on the
Theoretical Maximum Residue Contribution (TMRC) from existing and
pending tolerances for sethoxydim. (The TMRC is a ``worst case''
estimate of dietary exposure since it is assumed that 100% of all crops
for which tolerances are established are treated and that pesticide
residues are at the tolerance levels.)
i. Food. The TMRC from existing tolerances for the overall U.S.
population is estimated at approximately 44% of the RfD. BASF estimates
indicate that dietary exposure will not exceed the RfD for any
population subgroup for which EPA has data. This exposure assessment
relies on very conservative assumptions 100% of crops will contain
sethoxydim residues and those residues would be at the level of the
tolerance which results in an overestimate of human exposure.
ii. Drinking water. Based on the available studies submitted to EPA
for assessment of environmental risk, BASF does not anticipate
exposures to residues of sethoxydim in drinking water. There is no
established Maximum Concentration Level (MCL) for residues of
sethoxydim in drinking water under the Safe Drinking Water Act (SDWA).
2. Non-dietary exposure. BASF has not estimated non-occupational
exposure for sethoxydim. Sethoxydim is labeled for use by homeowners on
and around the following use sites: Flowers, evergreens, shrubs, trees,
fruits, vegetables, ornamental groundcovers, and bedding plants. Hence,
the potential for non-occupational exposure to the general population
exists. However, these use sites do not appreciably increase exposure.
Protective clothing requirements, including the use of gloves,
adequately protect homeowners when applying the product. The product
may only be applied through hose-end sprayers or tank sprayers as a
0.14% solution. Sethoxydim is not a volatile compound so inhalation
exposure during and after application would be negligible. Dermal
exposure would be minimal in light of the protective clothing and the
low application rate. According to BASF, post-treatment (re-entry)
exposure would be negligible for these use sites as contact with
treated surfaces would be low. BASF concludes that the potential for
non-occupational exposure to the general population is insignificant.
D. Cumulative Effects
BASF also considered the potential for cumulative effects of
sethoxydim and other substances that have a common mechanism of
toxicity. BASF is aware of one other active ingredient which is
structurally similar, clethodim. However, BASF believes that
consideration of a common mechanism of toxicity is not appropriate at
this time. BASF does not have any reliable information to indicate that
toxic effects produced by sethoxydim would be cumulative with clethodim
or any other chemical; thus, BASF is considering only the potential
risks of sethoxydim in its exposure assessment.
E. Safety Determination
1. U.S. population--Reference dose (RfD). Using the conservative
exposure assumptions described above, BASF has estimated that aggregate
exposure to sethoxydim will utilize 44% of the RfD for the U.S.
population. EPA generally has no concern for exposures below 100% of
the RfD. Therefore, based on the completeness and reliability of the
toxicity data, and the conservative exposure assessment, BASF concludes
that there is a reasonable certainty that no harm will result from
aggregate exposure to residues of sethoxydim, including all anticipated
dietary exposure and all other non-occupational exposures.
2. Infants and children--i. Developmental toxicity. Developmental
toxicity was observed in a developmental toxicity study using rats but
was not seen in a developmental toxicity study using rabbits. In the
developmental toxicity study in rats, a maternal NOAEL of 180 mg/kg/day
and a maternal LOAEL of 650 mg/kg/day (irregular gait, decreased
activity, excessive salivation, and anogenital staining) was
determined. A developmental NOAEL of 180 mg/kg/day and a developmental
LOAEL of 650 mg/kg/day (21 to 22% decrease in fetal weights,
filamentous tail and lack of tail due to the absence of sacral and/or
caudal vertebrae, and delayed ossification in the hyoids, vertebral
centrum and/or transverse processes, sternebrae and/or metatarsals, and
pubes). Since developmental effects were observed only at doses where
maternal toxicity was noted, the developmental effects observed are
believed to be secondary effects resulting from maternal stress.
ii. Reproductive toxicity. A 2-generation reproduction study with
rats fed diets containing 0, 150, 600, and 3,000 ppm (approximately 0,
7.5, 30, and 150 mg/kg/day) produced no reproductive effects during the
course of the study. Although the dose levels were insufficient to
elicit a toxic response, the Agency has considered this study usable
for regulatory purposes and has established a free-standing NOAEL of
3,000 ppm (approximately 150 mg/kg/day) (60 FR 13941).
iii. Reference dose. Based on the demonstrated lack of significant
developmental or reproductive toxicity, BASF believes that the RfD used
to assess safety to children should be the same as that for the general
population, 0.09 mg/kg/day. Using the conservative exposure assumptions
described above, BASF has concluded that the most sensitive child
population is that of children ages 1 to 6. BASF calculates the
exposure to this group to be approximately 95% of the RfD for all uses
(including those proposed in this document). Based on the completeness
and reliability of the toxicity data and the conservative exposure
assessment, BASF concludes that there is a reasonable certainty that no
harm will result to infants and children from aggregate exposure to the
residues of sethoxydim, including all anticipated dietary exposure and
all other non-occupational exposures.
F. International Tolerances
There are no Codex or Mexican maximum residue limits or tolerances
for sethoxydim on sweet corn. There is a Canadian tolerance on corn of
0.5 ppm for sethoxydim and metabolites containing the cyclohex-2-enone
moiety expressed as sethoxydim.
[FR Doc. 02-23088 Filed 9-10-02; 8:45 am]