dimethenamid (Frontier) Pesticide Tolerances 3/96
[Federal Register: March 15, 1996 (Volume 61, Number 52)]
ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 180
[PP 5F4549/R2213; FRL-5354-6]
Pesticide Tolerances for Dimethenamid
AGENCY: Environmental Protection Agency (EPA).
ACTION: Final Rule.
SUMMARY: This regulation establishes tolerances for residues of the
herbicide, dimethenamid, 1(R,S)-2-chloro-N-[(1-methyl-2-methoxy)ethyl]-N-(2,4-
dimethylthien-3-yl)-acetamide in or on the raw agricultural commodities
(RAC's) dry beans, peanut hay, peanut nutmeat, sorghum grain fodder,
sorghum grain forage, sorghum grain, sweetcorn (kernels plus cobs with
husks removed), sweetcorn fodder (stover) and sweetcorn forage at 0.01
parts per million (ppm). This regulation to establish the maximum
permissible level of residues of the herbicide in or on these
commodities was requested in a petition submitted by Sandoz Agro Inc.
DATES: This regulation becomes effective March 15, 1996.
ADDRESSES: Written objections and hearing requests, identified by the
docket number, [PP 5F4549/R2213], 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: 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: opp-
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 5F4549/R2213]. 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 below in this
FOR FURTHER INFORMATION CONTACT: By mail: Theresa A. Stowe, Acting Team
Leader, Product Manager (PM) 22, Registration Division, Environmental
Protection Agency, 401 M St., SW., Washington, DC 20460. Office
location and telephone number: Room 229, CM #2, 1921 Jefferson Davis
Highway, Arlington, VA 22202, (703-305-5540), e-mail:
SUPPLEMENTARY INFORMATION: EPA issued a notice published in the Federal
Register on November 15, 1995 (60 FR 57419) which announced that Sandoz
Agro Inc., 1300 East Touhy Avenue, Des Plaines, IL 60018, had submitted
a pesticide petition (PP 5F4549) 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), amend 40 CFR 180.464 to
establish tolerances for the residues of the herbicide, dimethenamid,
acetamide in or on the RAC's grain sorghum, sorghum fodder and sorghum
forage at 0.1 ppm, dry beans seed and dry bean straw/hay at 0.1 ppm,
sweetcorn (kernel plus cob with husk removed), sweetcorn forage,
sweetcorn dry grain, and sweet corn fodder (stover) at 0.01 ppm, and
peanut nutmeat, peanut forage, peanut hay and peanut hulls at 0.02 ppm.
Sandoz Agro Inc. subsequently amended the chemical name to read 1(R,S)-
corrected the RAC's to read dry beans, peanut hay, peanut nutmeat, sorghum
grain fodder, sorghum grain forage, sorghum grain, sweetcorn (Kernels plus
cobs with husks removed), sweetcorn fodder (stover) and sweetcorn forage, and
lowered the peanut tolerances to 0.01 ppm. There were no comments or requests
for referral to an advisory committee received in response to this notice of
The data submitted in the petitions and all other relevant material
have been evaluated. The toxicology data considered in support of the
1. A rat acute oral study with an LD50 of 2.14 grams (g)/kilogram (kg),
males, 1.30 g/kg females and 1.57 g/kg combined.
2. A 13-week rat feeding study with a no-observed effect level
(NOEL) of 500 ppm (33.5 milligrams (mg)/kg/day for males and 40.1 mg/
kg/day for females).
3. A 13-week dog feeding study with a NOEL of 100 ppm (2.5 mg/kg/
4. A 21 day rabbit dermal study with a NOEL of 50 mg/kg/day with
minimal to mild skin irritation at all dose levels.
5. A carcinogenicity study in mice with no carcinogenic effects
observed at any dose level under the conditions of the study and a
systemic NOEL of 300 ppm (40.8 mg/kg/day for males and 40.1 mg/kg/day
for females) and a systemic lowest effect level (LEL) of 1,500 ppm (205
mg/kg day for males and 200 mg/kg/day for females) based on
statistically significantly elevated corrected liver and kidney
6. A rat chronic feeding/carcinogenicity study with a systemic NOEL
of 100 ppm (5 mg/kg/day) and a LEL of 700 ppm (35 mg/kg/day) due to
decreased food efficiency and histopathology findings. Under the
conditions of the study limited evidence of carcinogenicity was
observed based on a statistically significant increasing trend for
benign liver cell tumors in male rats and a statistically significant
increasing trend for ovarian tubular adenomas in female rats. A
reevaluation of the ovarian neoplasia data indicated that there was no
statistically significant, dose-related, trend in the incidence of
ovarian tumors in female rats. This study is discussed further below.
7. A 1 year dog feeding study with a NOEL of 250 ppm (9.6 mg/kg/
day) and with a LEL = 1,250 ppm (49 mg/kg/day) based on clinical
chemistry and histological changes in liver.
8. A two generation reproduction study in rats with a parental and
reproductive NOEL of 500 ppm (36 mg/kg/day for males and 40 mg/kg/day
for females) and a parental and reproductive LEL of 2,000 ppm (150 mg/
kg/day for males and 160 mg/kg/day for females) based on reduction of
body weight and of food consumption, and increases in liver weights
(parental toxicity), and significant reductions in pup weight during
lactation (reproductive toxicity).
9. A rabbit developmental study with a maternal NOEL of 37.5 mg/kg/
day and a LEL of 75 mg/kg/day based on decreased body weight and food
consumption, and with a developmental NOEL of 75 mg/kg and a LEL of 150
mg/kg/day based on a low incidence of abortion/premature delivery and
angulation of the hyoid alae.
10. A rat developmental study with a maternal NOEL of 50 mg/kg/day
and a LEL of 215 mg/kg/day based on excess salivation, increased liver
weight and reduced body weight gain and food consumption, and with a
developmental NOEL of 215 mg/kg/day and a LEL of 425 mg/kg/day based on
11. An Ames mutagenicity assay negative with and without
activation, an in vitro chromosomal aberration using CHO cells weakly positive
with and without activation, a negative mouse bone marrow micronucleus study,
a negative BALB/3T3 cell transformation study, an unscheduled DNA synthesis in
rat hepatocytes unequivocally positive in one in vitro assay, negative in
another in vitro assay, and negative in one in vivo study, and a positive
dominant lethal study.
To further evaluate the mutagenic mechanism a heritable
translocation study is due March 15, 1998 (2 years after the date of
the conditional registration of dimethenamid for dry beans, peanuts,
sorghum and sweet corn under the Federal Insecticide Fungicide and
Rodenticide Act [FIFRA]).
The Agency has concluded that the available data provide limited
evidence of carcinogenicity for dimethenamid in rats and has classified
the pesticide as a Category C carcinogen (possible human carcinogen
with limited evidence of carcinogenicity in animals) in accordance with
Agency guidelines, published in the Federal Register in 1986 (51 FR
33992). Based on a review by the Health Effects Division Peer Review
Committee for Carcinogenicity of the Office of Pesticide Programs, the
Agency has determined that a quantitative risk assessment is not
appropriate for the following reasons:
1. The tumor response was primarily due to a significantly
increasing trend for benign and/or malignant liver tumors in males and
due to a significantly increasing trend for ovarian tubular adenomas in
female rats. A re-evaluation of the ovarian neoplasia data indicated
that there was not a statistically significant, dose-related, trend in
the incidence of ovarian tumors in female rats.
2. The chemical was not carcinogenic when administered in the diet
to mice at dose levels ranging from 30 to 3,000 ppm.
Based on this evidence, EPA concludes that dimethenamid poses at
most a negligible cancer risk to humans and that for purposes of risk
characterization the Reference Dose (RfD) approach should be used for
quantification of human risk. Residues of dimethenamid will not
concentrate in processed sweet corn, peanut, sorghum or dry bean
commodities and a food or feed additive regulation is not required for
The standard risk assessment approach of using the RfD based on
systemic toxicity was applied to dimethenamid. Using a 100-fold safety
factor and the NOEL of 5 mg/kg bwt/day determined by the most sensitive
species from the 2-year rat feeding study, the RfD is 0.05 mg/kg/day.
The Anticipated Residue Contribution (ARC) from the established
tolerances is 0.000071 mg/kg bwt/day and utilizes 0.14 percent of the
RfD for the overall U. S. population. The proposed use on dry beans,
peanuts, sorghum and sweetcorn would contribute an additional 0.000005
mg/kg/day, raising the ARC to 0.000076 mg/kg bwt/day, or 0.152 percent
of the RfD. For exposure of the most highly exposed subgroups in the
population, Non-nursing infants (1 year old), the TMRC is 0.000341 mg/
kg/day and utilizes 0.683 percent of the RfD.
Tolerances have been previously established for dimethenamid in
corn grain, corn fodder, corn forage and soybeans. The metabolism of
dimethenamid in plants is adequately understood. There is no reasonable
expectation of secondary residues occurring in meat, milk and eggs from
the tolerance associated with this petition.
An adequate analytical method, gas chromatography, is available for
enforcement purposes. Because of the long lead time from establishing
these tolerances to publication of the enforcement methodology in the
Pesticide Analytical Manual, Vol. II, the analytical methodology is
being made available in the interim to anyone interested in pesticide
enforcement when requested from: Calvin Furlow, Public Response and
Program Resources Branch, Field Operations Division (7506C), Office of
Pesticide Programs, Environmental Protection Agency, 401 M St., SW.,
Washington, DC 20460. Office location and telephone number: Room 1130A,
CM #2, 1921 Jefferson Davis Highway, Arlington, VA 22202, (703-305-5937).
The pesticide is considered useful for the purposes for which the
tolerances are sought. Based on the information and data considered,
the Agency concludes that the establishment of the tolerances 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 that 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 5F4549] (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
address in "ADDRESSES" at the beginning of this document.
Under Executive Order 12866 (58 FR 51735, October 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 6, 1996.
Director, Registration Division, Office of Pesticide Porgrams.
Therefore, chapter I of title 40 Code of Federal Regulations is
amended as follows:
1. The authority citation for Part 180 continues to read as
Authority: 21 U.S.C. 346a and 371.
2. In Sec. 180.464, by revising the introductory paragraph and amending
the table by alphabetically adding the raw agricultural commodities, "corn,
sweet, fodder (stover)" and "corn, sweet, forage," "corn, sweet (Kernels plus
cobs with husks removed)," "dry beans," "peanut hay," "peanut nutmeat,"
"sorghum grain fodder," "sorghum grain forage," "sorghum grain", to read as
Sec. 180.464 Dimethenamid, 1(R,S)-2-chloro-N-[(1-methyl-2-methoxy)ethyl]-N-
(2,4-dimethylthien-3-yl)-acetamide; tolerance for residues.
Tolerances are established for residues of the herbicide dimethenamid,
acetamide in or on the following raw agricultural commodities:
Beans, dry..................................................... 0.01
* * * * *
Corn, sweet, fodder (stover)................................... 0.01
Corn, sweet, forage............................................ 0.01
Corn, sweet (Kernels plus cobs with husks removed)............. 0.01
Peanut, hay.................................................... 0.01
Peanut, nutmeat................................................ 0.01
Sorghum, grain, fodder......................................... 0.01
Sorghum, grain, forage......................................... 0.01
Sorghum, grain................................................. 0.01
* * * * *