sethoxydim (Poast) Pesticide Tolerance 3/91
ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 180
[PP 0F3831 and PP 9F3806/R1106; FRL-3876-7]
Pesticide Tolerances for 2-[1-(Ethoxyimino)Butyl]-5-[2-Ethylthio)Propyl]3-
AGENCY: Environmental Protection Agency (EPA)
ACTION: Final rule.
SUMMARY: This document establishes a tolerance for the herbicide 2-[1-
(sethoxydim) (Poast) and its metabolites containing the 2 cyclohexene-1-one
moiety, calculated as the herbicide in or on the raw agricultural commodities
(RACs) field corn grain at 0.1 part per million (ppm), sweet corn (kernel plus
cob with husk removed [K + CWHR]) at 0.2 ppm, corn forage at 0.2 ppm, corn
fodder at 0.2 ppm and strawberries at 10.0 ppm. This regulation was requested
by BASF Wyandotte Corp. and established the maximum permissible levels for
residues of the herbicide in or on these RACs.
EFFECTIVE DATE: This regulation becomes effective March 20, 1991.
ADDRESSES: Written objections, identified by the document control number, [PP
0F3831 and PP 9F3806/R1106], may be submitted to: Hearing Clerk (A-110),
Environmental Protection Agency, Rm. 3708, 401 M St., SW., Washington, DC
FOR FURTHER INFORMATION CONTACT: By mail: Robert J. Taylor, Product Manger
(PM) 25, (H7505C), Registration Division, Environmental Protection Agency, 401
M St., SW., Washington, DC 20460. Office location and telephone number: Rm.
245, CM #2, 1921 Jefferson Davis Highway, Arlington, VA 22202, (703) 557-
SUPPLEMENTARY INFORMATION: EPA has issued notices in the Federal Register
announcing that BASF Corp. 100 Cherry Hill Rd., Parsippany, NJ 07054, had
submitted pesticide petitions to EPA proposing to amend 40 CFR part 180 by
establishing regulations to permit combined residues of the herbicide 2-[(1-
(sethoxydim) and its metabolites containing the 2-cyclohexene-1-one moiety,
calculated as the herbicide, in or on certain raw agricultural commodities.
1. PP 0F3831. Published in the Federal Register of June 29, 1990 (54 FR
26751), the notice proposed establishing a regulation to permit residues of
the herbicide in or on strawberries at 10.0 ppm.
2. PP 9F3806. Published in the Federal Register of January 9, 1990 (54 FR
779), the notice proposed establishing a regulation to permit residues of the
herbicide in or on the raw agricultural commodities (RACs) field corn grain at
0.1 part per million (ppm), sweet corn (K + CWHR) at 0.2 ppm, corn forage at
0.2 ppm, and corn fodder at 0.2 ppm.
There were no comments or requests for referral to an advisory committee
received in response to the notices.
The data submitted in the petition and other relevant material have been
evaluated. The toxicology data listed below were considered in support of
1. Several acute toxicology studies placing technical-grade sethoxydim in
Toxicity Category III.
2. A subchronic feeding study in dogs fed dosage levels of 0, 20, and 200
milligram per kilogram of body weight per day (mg/kg/bwt/day) with a no-
observed-effect level (NOEL) of 20 mg/kg/day based on liver effects and
nonspecific anemia at 200 mg/kg/day.
3. A 1-year feeding study with dogs fed dosages (based on consumption) of 9,
8.86/9.41, and 17.5/19.9, and 110/129 mg/kg/day (males/females) with a NOEL of
8.86/9.41 mg/kg/day (males/females) based on equivocal anemia in males and
females at 17.5/19.9 mg/kg/day, respectively.
4. A 2-year chronic feeding/carcinogenicity study with mice fed dosages of 0,
6, 18, 54, and 162 mg/kg/day with no carcinogenic effects observed under the
conditions of the study at dose levels up to an including 162 mg/kg/day
(highest dose tested [HDT]) and a systemic NOEL of 18 mg/kg/day.
5. A 2-year chronic feeding/carcinogenicity study with mice fed dosages of 0,
2, 6, and 18 mg/kg/day (HDT) with no carcinogenic effects observed under the
conditions of the study at dose levels up to an including 18 mg/kg/day (HDT),
and a systemic NOEL greater than or equal to 18 mg/kg/day.
6. A developmental toxicity study in rats fed dosages of 0, 40, 100, 250
mg/kg/day, with no developmental effects occurring at 250 mg/kg/day (HDT), and
a maternal NOEL of 40 mg/kg/day based on significantly decreased adrenal
weights at 100 mg/kg/day.
7. A development toxicity study in rabbits fed dosage levels of 0, 40, 160,
and 480 mg/kg/day with a maternal toxicity NOEL of 160 mg/kg/day (severe
weight loss, an excess number of maternal deaths, abortions, and fetal
resorptions and absorptions occurred at 480 mg/kg/day [HDT]). Due to the
extreme maternal toxicity of the chemical at the 480 mg/kg/day dose, it was
difficult to determine whether the increased resorptions and absorptions were
due to maternal toxicity or to fetotoxicity.
8. Mutagenic studies, including a host-mediated assay (mouse) with S.
typhimurium, negative at 2.5 grams/kg/day of chemical, and recombinant assay
and forward mutations in B. subtilis, E. coli, and S. typhimurium (all
negative at concentrations of the chemical up to 100 percent).
Based on the NOEL of 8.86 mg/kg/bwt/day in the 1-year dog feeding study, and
using a hundredfold uncertainty factor, the acceptable daily intake (ADI) for
sethoxydim is calculated to be 0.09 mg/kg bwt/day. The theoretical maximum
residue contribution (TMRC) is 0.031551 mg/kg bwt/day for existing tolerances
for the overall U.S. population. The current action will increase the TMRC by
0.000410 mg/kg bwt/day (<1 percent of the ADI). These tolerances and
previously established tolerances utilize a total of 35.51 percent of the ADI
for the overall U.S. population. For U.S. subgroup populations, nonursing
infants and children aged 1 to 6, the current action and previously
established tolerances utilize, respectively, a total of 59.57 percent and
71.82 percent of the ADI, assuming that residue levels are at the established
tolerances and that 100 percent of the crop is treated.
Data lacking are a repeat of a rat primary hepatocyte unscheduled DNA
synthesis assay on a hydroxylated plant metabolite of the parent compound.
The company has been notified of this deficiency and has agreed to repeat the
The pesticide is useful for the purposes for which these tolerances are
sought. The nature of the residue is adequately understood, and adequate
analytical methods (gas chromatography using sulfur-specific flame photometric
detection) are available for enforcement purposes. The method is listed in h
Pesticide Analytical Manual, Vol. II (PAM II), as Method I. There are
currently no actions pending against the registration of this chemical.
Based on the information cited above, the Agency has determined that the
establishment of the tolerances by amending 40 CFR part 180 will protect the
public health. Therefore, the tolerances are established as set forth below.
Any person adversely affected by this regulation may, within 30 days after
publication of this document in the Federal Register, file written objections
and/or request for a hearing with the Hearing Clerk, at the address given
above. Such objections should specify the provisions of the regulation deemed
objectionable and the grounds for the objections. A hearing will be granted
if the objections are supported by grounds legally sufficient to justify the
The Office of Management and Budget has exempted this rule from the
requirements of section 3 of Executive Order 12291,.
Pursuant to the requirements of the Regulatory Flexibility Act (Pub. L. 96-
354, 94 Stat. 1164, 5 U.S.C. 601-612), the Administrator has determined that
regulations establishing new tolerances or raising tolerance levels or
establishing exemptions from tolerance requirements do not have a significant
economic impact on a substantial number of small entities. A certification
statement to this effect was published in the Federal Register of May 4, 1981
(46 FR 24950).
List of Subjects in 40 CFR Part 180
Administrative practice and procedure, Agricultural commodities, Pesticides
and pests, Reporting and recordkeeping requirements.
Dated: February 26, 1991.
Susan H. Wayland
Acting Director, Office of Pesticide Programs.
Therefore, 40 CFR part 180 is amended as follows:
1. The authority citation for part 180 continues to read as follows:
Authority: 21 U.S.C. 346a and 371.
2. In Section 180.412(a), by adding and alphabetically inserting entries for
the raw agricultural commodities corn, field, grain; corn, sweet (K + CWHR);
corn fodder; and corn forage and revising the entry for strawberries, to read
Section 180.412 2-(1-Ethoxyimino)butyl]-5-[2-(ethyithio)propyl]-3-hydroxy-2-
cyclohexene-1-one; tolerances for residues.
(a) * * *
Commodities Parts Per Million
Corn, field, grain 0.1
Corn fodder 0.2
Corn forage 0.2
Corn, sweet (K + CWHR) 0.2
[FR Doc. 91-6219 Filed 3-19-91; 8:45 am]
Billing Code 6560-50-F