Tribenuron Methyl - Pesticide Tolerance 4/96
ENVIRONMENTAL PROTECTION AGENCY
40 CFR PART 180
[PP 4F4322/R2217; FRL-5356-4]
Pesticide Tolerance for Tribenuron Methyl
AGENCY: Environmental Protection Agency (EPA).
ACTION: Final Rule.
SUMMARY: This rule establishes tolerances for residues of the herbicide
tribenuron methyl (methyl-2[[[[N-(4-methoxy-6-methyl-1,3,5-triazin-2-
yl) methylamino] carbonyl]amino]sulfonyl] benzoate) in or on the raw
agricultural commodities (RACs) hay of grass forage, fodder and hay
group (excluding Bermudagrass) at 0.10 ppm; and forage grass forage,
fodder and hay group (excluding Bermudagrass) at 0.10 ppm. This
regulation to establish a maximum permissible level for residues of
tribenuron methyl was requested in a petition submitted by E.I. DuPont
de Nemours Company, Inc. Agricultural Products, Walker Mill, Barley
Mill Plaza, P.O. Box 80038. Wilmington, DE 19880-0038.
EFFECTIVE DATE: April 3, 1996.
ADDRESSES: Written objections and hearing requests, identified by the
docket number, [PP 4F4322/R2217], may be submitted to: Hearing Clerk
(1900), Environmental Protection Agency, Rm. M3708, 401 M St., SW.,
Washington, DC 20460. A copy of any objections and hearing requests
filed with the Hearing Clerk should be identified by the docket number
and submitted to: Public Response and Program Resources Branch, Field
Operations Division (7506C), Office of Pesticide Programs,
Environmental Protection Agency, 401 M St., SW., Washington, DC 20460.
In person, bring copies of objections and hearing requests to Rm. 1132,
CM #2, 1921 Jefferson Davis Hwy., Arlington, VA 22202. Fees
accompanying objections shall be labeled "Tolerance Petition Fees"
and forwarded to: EPA Headquarters Accounting Operations Branch, OPP
(Tolerance Fees), P.O. Box 360277M, Pittsburgh, PA 15251. An electronic
copy of objections and hearing requests filed with the Hearing Clerk
may be submitted to OPP by sending electronic mail (e-mail) to:
Copies of electronic objections and hearing requests must be
submitted as an ASCII file avoiding the use of special characters and
any form of encryption. Copies of electronic objections and hearing
requests will also be accepted on disks in WordPerfect 5.1 file format
or ASCII file format. All copies of electronic objections and hearing
requests must be identified by the docket number [PP 4F4322/R2217]. No
Confidential Business Information (CBI) should be submitted through e-
mail. Copies of electronic objections and hearing requests on this rule
may be filed online at many Federal Depository Libraries. Additional
information on electronic submissions can be found in the SUPPLEMENTARY
INFORMATION section of this document.
FOR FURTHER INFORMATION CONTACT: By mail: Joanne Miller, Product
Manager (23) Registration Division (7505C), Office of Pesticide
Programs. Environmental Protection Agency, 401 M St. SW., Washington,
DC 20460. Office location and telephone number: Rm. 237, CM #2, 1921
Jefferson Davis Highway, Arlington, VA 22202, 703-305-6224.
SUPPLEMENTARY INFORMATION: EPA issued a notice of filing, published in
the Federal Register of July 13, l994 (59 FR 35719), which announced
that DuPont, Agricultural Products, Walker's Mill, Barley Mill Plaza
P.O. Box 80038, Wilmington, DE had submitted a pesticide petition, PP
4F4322, to EPA requesting that the Administrator, pursuant to section
408(d) of the Federal Food, Drug, and Cosmetic Act (FFDCA), 21 U.S.C.
346a(d), establish tolerances for combined residues of the herbicide
tribenuron methyl (methyl-2[[[[N-(4-methoxy-6-methyl 1,3,5-triazin-2-
yl) methylamino] carbonyl]amino]sulfonyl]benzoate in or on grass, seed;
grass seed straw; grass, seed cleanings (screenings) at 0.04 ppm. A
second notice of filing was issued on February 1, l996, published in
the Federal Register (61 FR 3696), which announced that DuPont had
amended the petition by revising the requested tolerances to read: in
or on the raw agricultural commodities hay of grass forage, fodder and
hay group (excluding Bermudagrass) at 0.10 ppm; forage of grass forage,
fodder and hay group (excluding Bermudagrass) at 0.10 ppm and forage
regrowth at 0.10 ppm. The analytical method for determining residues is
high performance liquid chromatography with photo-conductivity detection.
There were no comments received in response to the notices of
filing. The scientific data submitted in the petition and other
relevant material have been evaluated. The toxicological data
considered in support of the proposed tolerances include:
1. The following acute studies with tribenuron methyl (DPX-L5300):
Acute Oral, Rat: LD50 >5,000 mg/kg, Toxicity Category IV.
Acute Dermal, Rabbit: LC50 >2000 mg/kg, Toxicity Category IV.
Acute Inhalation, Rat: >6.7 mg/L/4hr, Toxicity Category IV.
Primary Eye Irritation, Rabbit: Toxicity Category IV.
Primary Dermal Irritation, Guinea Pig: Toxicity Category IV.
Dermal Sensitiation, Guinea Pig: nonsensitizing.
2. A 3-month feeding study, Rat: No-observed-effect-level (NOEL) =
7/8 mg/kg/day and Lowest effect level (LEL) = 118/135 mg/kg/day.
Toxicity observed: decreased body weight gain, food consumption and
food efficiency; decreased absolute heart, liver, and kidney weights;
increased relative brain, heart, liver, kidney, testes, and spleen
weights; decreased serum glucose and globulin; no histopathologic
lesions; likely cachexia.
3. A 3-month feeding study, Dog: NOEL = 73.3/78.0 mg/kg/day (HDT).
4. A 28-day dermal, Rabbit; The limit dose, 1,000 mg/kg/day,
resulted in serious toxicity and death, NOEL and LEL could not be
defined. Toxicity included treatment site lesions, hypokinesia,
decreased body weights and food consumption, and kidney pathology, but
the cause of death could not be determined. Although the study was Core
Supplementary, another study is not needed. Worker expsure is expected
to be 4 to 5 orders of magnitude less than the limit dose.
5. Chronic feeding, Dog: NOEL (females) = 0.79 mg/kg/day, NOEL
(males) = 8.16 mg/kg/day; LEL (males) = 8.18 mg/kg/day, with elevated
serum bilirubin, AST, and urinary volume, and LEL (females) = 52.02 mg/
kg/day with increased serum creatinine, bilirubin, AST, and globulin,
decreased body weight gain of 18.2%.
6. Carcinogenicity, Mouse: NOEL (males) = 3 mg/kg/day and LEL
(males) = 30 mg/kg/day, with bilateral seminiferous degeneration and
oligospermia. Although frank toxicity was not observed in the females,
Health Effects Division (HED) peer review judged the dose levels to be
adequate. There was no evidence of carcinogenicity.
7. Developmental toxicity, Rat: Maternal NOEL = 20 mg/kg/day;
Maternal LEL = 125 mg/kg/day, with decreased maternal body weight gain
and food consumption; Developmental NOEL = 20 mg/kg/day; Developmental
LEL = 125 mg/kg/day, with decreased body weight; at 500 mg/kg/day (HDT)
there were increased resorptions, fetal deaths, and incomplete
8. Developmental toxicity, Rabbit: Maternal NOEL = 20 mg/kg/day,
Maternal LEL = 80 mg/kg/day (HDT - decreased food consumption,
increased abortions); Developmental NOEL = 20 mg/kg/day, Development
LEL = 80 mg/kg/day (HDT - 10% decrease in body weight compared to
controls, not statistically significant). Abortions were increased at
89 mg/kg/day. No terata were observed.
9. 2-generation reproduction, Rat: Paternal NOEL = 2.0 mg/kg/day,
Paternal LEL = 21.0 mg/kg/day, with decreased body weight gain in F1a
adult females; Reproductive NOEL = 2.5 mg/kg/day, Reproductive LEL = 25
mg/kg/day, with decreased body weight gain during lactation for F1b and
10. Chronic feeding/carcinogenicity, Rat: NOEL = 0.95/1.2 mg/kg/
day, LEL = 10/13 mg/kg/day, with decreased body weight gain in both
sexes. Statistically significant increase in mammary gland
adenocarcinomas in female rats at 76 mg/kg/day, HDT. Health Effects
Division Peer Review Committee classified tribenuron methyl a Category
C (possible human carcinogen) under EPA's cancer assessment guidelines.
11. Gene mutation: Ames Assay: Negative for Salmonella strains
TA97, TA98, TA100 and TA1535 with and without metabolic activation.
12. Structural chromosome: Micronucleus Assay in Mouse Bone Marrow.
Negative at a cytotoxic dose. In vivo Cytogenetic Assay in Rat.
13. Other genotoxic effects: In vitro Point Mutation in CHO Cells.
14. Unscheduled DNA synthesis in rats. Negative.
15. Metabolism: Rats given a single dose of 20 or 1,800 mg/kg
excreted 99% or 97%, respectively, of radiolabel within 96 hours. The
major route of excretion is the urine (2 to 4 times the amount excreted
in feces). No more than 1% of radiolabel was found in any one tissue or
organ 7 days. Major metabolites in the urine and feces included
metsulfuron methyl, saccharin, and O-dimethyl triazine amine. The two
major metabolic routes are the demethylation of the carbamoyl methyl
group and the hydrolysis of the carbamate moiety.
16. Estrogenic Activity in Rats: Weak estrogenic activity was
observed in female rats.
The Reference Dose (RfD) is established at 0.008 mg/kg/day, based
on the 1 year dog feeding study NOEL of 0.79 mg/kg/day and an
uncertainty factor of 100. The NOEL is taken from a 1 year feeding
study in dogs which demonstrated as an effect elevated serum bilirubin
and AST levels. The result from the EPA Dietary Risk Evaluation System
for chronic analysis of dietary risk from all raw agricultural
commodities (RACs) for which tolerances have been established (40 CFR
180.451) was published (FRL-4759-4) in the Federal Register (59 FR
17755, April 14, l994). Based on the information published the
Theoretical Maximum Residue Contribution (TMRC) for the general
population is now estimated to be 7.8 x 10**-5 mg/kg bwt/day, or
1% of the RfD (viz. 0.97). The addition of forage and hay of grasses
associated with the use of tribenuron methyl in the culture of grass
seeds in the states of Washington, Oregon and Idaho under a regional
registration will not increase the risk by more than a fraction of 1%,
because of the low potential for transfer of residues of tribenuron
methyl in ruminants. In a lactating goat study with labeled tribenuron
methyl at a level of 6.7 ppm there was a total of 0.5% of the
administered dose found in the assayed tissues and organs. Based on
this low potential for transfer of residues to tissues, the Agency has
concluded that feeding studies and animal tolerances for tribenuron
methyl are not required. The proposed tolerances for grass RACs are at
the same level as established for barley, oats, and wheat straw in
ruminant diets, the proposed tolerances for the grass RACs will not
increase the dietary burden for residues of tribenuron methyl in
ruminants. Therefore no tolerances are needed for secondary residues in
animal tissues and in milk. There are no human dietary RACs associated
with the proposed registration of tribenuron methyl for use in the
production of grass seed.
Tribenuron methyl is considered a class C carcinogen with no
Q* established for quantification of potency. EPA considers the
cancer risk from exposure to tribenuron methyl from use as registered
under the Federal Insecticide, Fungicide and Rodenticide Act as amended
to be negligible.
The petitioner requested a petition for tolerances with regional
registration based on the claim that the pesticide would not be used in
grass seed production areas other than in the state of Washington,
Oregon, and Idaho, because of the culture practices in those state. Residue
chemistry data supporting this regulatory action were limited to data from the
Pacific Northwestern states mentioned above.
An adequate analytical method, high performance liquid
chromatography with photo-conductivity detection, is available for
There are presently no actions pending against the continued
registration of this chemical. The pesticide is considered useful for
the purpose for which the tolerances are being sought.
Based on the information and data considered, the Agency has
determined that the tolerances established by amending 40 CFR 180.451
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 to the regulation and may also request a hearing on
those objections. Objections and hearing requests must be filed with
the Hearing Clerk, at the address given above (40 CFR 178.20). A copy
of the objections and/or hearing requests filed with the Hearing Clerk
should be submitted to the OPP docket for this rulemaking. The
objections submitted must specify the provisions of the regulation
deemed objectionable and the grounds for the objections (40 CFR
178.25). Each objection must be accompanied by the fee prescribed by 40
CFR 180.33(i). If a hearing is requested, the objections must include a
statement of the factual issue(s) on which a hearing is requested, the
requestor's contentions on such issues, and a summary of any evidence
relied upon by the objector (40 CFR 178.27). A request for a hearing
will be granted if the Administrator determines tht the material
submitted shows the following: There is genuine and substantial issue
of fact; there is a reasonable possibility that available evidence
identified by the requestor would, if established, resolve one or more
of such issues in favor of the requestor, taking into account
uncontested claims or facts to the contrary; and resolution of the
factual issue(s) in the manner sought by the requestor would be
adequate to justify the action requested (40 CFR 178.32).
EPA has established a record for this rulemaking under docket
number [PP-4F4322/R2217] (including any comments and data submitted
electronically). A public version of this record, including printed,
paper versions of electronic comments, which does not include any
information claimed as CBI, is available for inspection from 8 a.m. to
4:30 p.m., Monday through Friday, excluding legal holidays. The public
record is located in Room 1132 of the Public Response and Program
Resources Branch, Field Operations Division (7506C), Office of
Pesticide Programs, Environmental Protection Agency, Crystal Mall #2,
1921 Jefferson Davis Highway, Arlington, VA.
Electronic comments may be sent directly to EPA at:
Electronic comments must be submitted as an ASCII file avoiding the
use of special characters and any form of encryption.
The official record for this rulemaking, as well as the public
version, as described above will be kept in paper form. Accordingly,
EPA will transfer any copies of objections and hearing requests
received electronically into printed, paper form as they are received
and will place the paper copies in the official rulemaking record which
will also include all comments submitted directly in writing. The
official rulemaking record is the paper record maintained at the
Virginia address in "ADDRESSES" at the beginning of this document.
Under Executive Order 12866 (58 FR 51735, Oct. 4, 1993), the Agency
must determine whether the regulatory action is "significant" and
therefore subject to all the requirements of the Executive Order (i.e.,
Regulatory Impact Analysis, review by the Office of Management and
Budget (OMB)). Under section 3(f), the order defines "significant" as
those actions likely to lead to a rule (1) having an annual effect on
the economy of $100 million or more, or adversely and materially
affecting a sector of the economy, productivity, competition, jobs, the
environment, public health or safety, or State, local or tribal
governments or communities (also known as "economically
significant"); (2) creating serious inconsistency or otherwise
interfering with an action taken or planned by another agency; (3)
materially altering the budgetary impacts of entitlement, grants, user
fees, or loan programs; or (4) raising novel legal or policy issues
arising out of legal mandates, the President's priorities, or the
principles set forth in this Executive Order.
Pursuant to the terms of this Executive Order, EPA has determined
that this rule is not "significant" and is therefore not subject to
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
Environmental protection, Administrative practice and procedure,
Agricultural commodities, Pesticides and pests, Reporting and
Dated: March 22, 1996.
Stephen L. Johnson,
Director, Registration Division, 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 Sec. 180.451 by revising the section heading to read as set
forth below, designating the existing text as paragraph (a), and by
adding a new paragraph (b), to read as follows:
Sec. 180.451 Tribenuron methyl; tolerances for residues.
(a) * * *
(b) Tolerances with regional registration, as defined in
Sec. 180.1(n) are established for residues of the herbicide tribenuron
methyl (methyl-2-[[[[N-(4-methoxy-6-methyl-1,3,5- triazin-2-yl)
methylamino] carbonyl]amino]sulfonyl]benzoate) in or on the following
raw agricultural commodities:
Grass forage, fodder and hay group (except Bermudagrass);
Grass forage, fodder and hay group (except Bermudagrass); hay.. 0.10