Dimethenamid; Pesticide Tolerances for Emergency Exemptions

Note: EPA no longer updates this information, but it may be useful as a reference or resource.

[Federal Register: August 24, 2000 (Volume 65, Number 165)]
[Rules and Regulations]
[Page 51544-51552]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr24au00-21]

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 180

[OPP-301038; FRL-6738-1]
RIN 2070-AB78

Dimethenamid; Pesticide Tolerances for Emergency Exemptions

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

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SUMMARY: This regulation establishes time-limited tolerances for
residues of

[[Page 51545]]

dimethenamid, 2-chloro-N-[(1-methyl-2-methoxy)ethyl]-N-(2,4-
dimethylthien-3-yl)-acetamide in or on dry bulb onions, sugar beets
roots, tops, pulp and molasses. This action is in response to EPA's
granting of an emergency exemption under section 18 of the Federal
Insecticide, Fungicide, and Rodenticide Act authorizing use of the
pesticide on dry bulb onions and sugar beets. This regulation
establishes a maximum permissible level for residues of dimethenamid in
these food commodities. The tolerances will expire and are revoked on
December 31, 2002.

DATES: This regulation is effective August 24, 2000. Objections and
requests for hearings, identified by docket control number OPP-301038,
must be received by EPA on or before October 23, 2000.

ADDRESSES: Written objections and hearing requests may be submitted by
mail, in person, or by courier. Please follow the detailed instructions
for each method as provided in Unit VII. of the SUPPLEMENTARY
INFORMATION. To ensure proper receipt by EPA, your objections and
hearing requests must identify docket control number OPP-301038 in the
subject line on the first page of your response.

FOR FURTHER INFORMATION CONTACT: By mail: Barbara Madden, Registration
Division (7505C), Office of Pesticide Programs, Environmental
Protection Agency, 1200 Pennsylvania Ave., NW., Washington, DC 20460;
telephone number: (703) 305-6463; and e-mail address:
madden.barbara@epa.gov.

SUPPLEMENTARY INFORMATION:

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.
Potentially affected categories and entities may include, but are not
limited to:

------------------------------------------------------------------------
Examples of Potentially
Categories NAICS Affected Entities
------------------------------------------------------------------------
Industry 111 Crop production
112 Animal production
311 Food manufacturing
32532 Pesticide 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
CONTACT.

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,'' ``Regulations and Proposed Rules,'' 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 control number OPP-301038. The official record
consists of the documents specifically referenced in this action, 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 Hwy.,
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.

II. Background and Statutory Findings

EPA, on its own initiative, in accordance with sections 408(e) and
408 (l)(6) of the Federal Food, Drug, and Cosmetic Act (FFDCA), 21
U.S.C. 346a, is establishing tolerances for residues of the herbicide
dimethenamid, 2-chloro-N-[(1-methyl-2-methoxy)ethyl]-N-(2,4-
dimethylthien-3-yl)-acetamide, in or on dry bulb onions at 0.01 part
per million (ppm), sugar beets roots and tops at 0.01 ppm and sugar
beet dry pulp and molasses at 0.05 ppm. These tolerances will expire
and are revoked on December 31, 2002. EPA will publish a document in
the Federal Register to remove the revoked tolerances from the Code of
Federal Regulations.
Section 408(l)(6) of the FFDCA requires EPA to establish a time-
limited tolerance or exemption from the requirement for a tolerance for
pesticide chemical residues in food that will result from the use of a
pesticide under an emergency exemption granted by EPA under section 18
of FIFRA. Such tolerances can be established without providing notice
or period for public comment. EPA does not intend for its actions on
section 18 related tolerances to set binding precedents for the
application of section 408 and the new safety standard to other
tolerances and exemptions.
Section 408(b)(2)(A)(i) of the 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) 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)
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. . . .''
Section 18 of the Federal Insecticide, Fungicide, and Rodenticide
Act (FIFRA) authorizes EPA to exempt any Federal or State agency from
any provision of FIFRA, if EPA determines that ``emergency conditions
exist which require such exemption.'' This provision was not amended by
the Food Quality Protection Act (FQPA). EPA has established regulations
governing such emergency exemptions in 40 CFR part 166.

III. Emergency Exemption for Dimethenamid on Onions and Sugar Beets
and FFDCA Tolerances

1. Onions. Onions in New York are seeded in early spring in cool
soils and, therefore, grow very slowly during the first weeks of the
season, thus, onions can quickly be overrun by early germinating weeds.
Because of the manner in which an onion plant grows,

[[Page 51546]]

it never develops a leaf canopy that shades the soil as effectively as
do most crops. Consequently, an onion crop remains subject to weed
competition throughout the growing season. Any weeds not controlled
during the first 6-8 weeks usually must be removed by hand, as they are
no longer susceptible to most postemergence herbicides and cannot be
removed by mechanical cultivation. For weeds within the onion row, even
hand weeding becomes impractical as weeds get large because they cannot
be pulled out of the soil without uprooting adjacent onion plants.
Until the mid 1980's, New York onion growers relied on the
herbicide, Randox, for effective broad spectrum weed control. After
Randox was discontinued, it was replaced primarily by Prowl. However,
Prowl has no activity on yellow nutsedge and in the last 10 to 15 years
almost all of muck soil onion fields have been infested with yellow
nutsedge. Prowl also fails to control a number of other broad leaf
weeds that Randox once controlled. Dual, a herbicide registered for use
to control yellow nutsedge, only provides limited control because it
can not be used until the onions are in the 2-leaf stage and in most
cases yellow nutsedge infestations are out of control by that time.
2. Sugar Beets. Historically, one application of Ro-Neet applied
alone or sequentially with one application of Eptam, followed by one or
two cultivations provided acceptable season-long control of weeds for
many Washington sugar beet growers. By 1998, growers began to question
whether products that had once provided effective control in sugar
beets were still providing acceptable levels of control. By the 1999
growing season, growers felt that currently registered herbicides were
no longer sufficient to allow cost effective sugar beet production.
EPA has authorized under FIFRA section 18 the use of dimethenamid
on dry bulb onions in New York and sugar beets in Washington for
control of weeds. After having reviewed the submission, EPA concurs
that emergency conditions exist for these States.
As part of its assessment of this emergency exemption, EPA assessed
the potential risks presented by residues of dimethenamid in or on dry
bulb onions and sugar beets. In doing so, EPA considered the safety
standard in FFDCA section 408(b)(2), and EPA decided that the necessary
tolerances under FFDCA section 408(l)(6) would be consistent with the
safety standard and with FIFRA section 18. Consistent with the need to
move quickly on the emergency exemption in order to address an urgent
non-routine situation and to ensure that the resulting food is safe and
lawful, EPA is issuing these tolerances without notice and opportunity
for public comment as provided in section 408(l)(6). Although these
tolerances will expire and are revoked on December 31, 2002, under
FFDCA section 408(l)(5), residues of the pesticide not in excess of the
amounts specified in the tolerance remaining in or on dry bulb onions
and sugar beets after that date will not be unlawful, provided the
pesticide is applied in a manner that was lawful under FIFRA, and the
residues do not exceed a level that was authorized by these tolerances
at the time of that application. EPA will take action to revoke these
tolerances earlier if any experience with, scientific data on, or other
relevant information on this pesticide indicate that the residues are
not safe.
Because these tolerances are being approved under emergency
conditions, EPA has not made any decisions about whether dimethenamid
meets EPA's registration requirements for use on dry bulb onions and
sugar beets or whether a permanent tolerance for this use would be
appropriate. Under these circumstances, EPA does not believe that these
tolerances serve as a basis for registration of dimethenamid by a State
for special local needs under FIFRA section 24(c). Nor do these
tolerances serve as the basis for any State other than New York and
Washington to use this pesticide on these crops under section 18 of
FIFRA without following all provisions of EPA's regulations
implementing section 18 as identified in 40 CFR part 166. For
additional information regarding the emergency exemption for
dimethenamid, contact the Agency's Registration Division at the address
provided under FOR FURTHER INFORMATION CONTACT.

IV. Aggregate Risk Assessment and Determination of Safety

EPA performs a number of analyses to determine the risks from
aggregate exposure to pesticide residues. For further discussion of the
regulatory requirements of section 408 and a complete description of
the risk assessment process, see the final rule on Bifenthrin Pesticide
Tolerances (62 FR 62961, November 26, 1997) (FRL-5754-7).
Consistent with 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
dimethenamid and to make a determination on aggregate exposure,
consistent with section 408(b)(2), for time-limited tolerances for
residues of dimethenamid in or on dry bulb onions at 0.01 ppm, sugar
beets roots and tops at 0.01 ppm and sugar beet dry pulp and molasses
at 0.05 ppm. EPA's assessment of the dietary exposures and risks
associated with establishing the tolerances follows.

A. Toxicological Endpoints

The dose at which no adverse effects are observed (NOAEL) from the
toxicology study identified as appropriate for use in risk assessment
is used to estimate the toxicological endpoint. However, the lowest
dose at which adverse effects of concern are identified (LOAEL) is
sometimes used for risk assessment if no NOAEL was achieved in the
toxicology study selected. An uncertainty factor (UF) is applied to
reflect uncertainties inherent in the extrapolation from laboratory
animal data to humans and in the variations in sensitivity among
members of the human population as well as other unknowns. An UF of 100
is routinely used, 10X to account for interspecies differences and 10x
for intraspecies differences.
For dietary risk assessment (other than cancer) the Agency uses the
UF to calculate an acute or chronic reference dose (acute RfD or
chronic RfD) where the RfD is equal to the NOAEL divided by the
appropriate UF (RfD = NOAEL/UF). Where an additional safety factor is
retained due to concerns unique to the FQPA, this additional factor is
applied to the RfD by dividing the RfD by such additional factor. The
acute or chronic Population Adjusted Dose (aPAD or cPAD) is a
modification of the RfD to accommodate this type of FQPA Safety Factor.
For non-dietary risk assessments (other than cancer) the UF is used
to determine the level of concern (LOC). For example, when 100 is the
appropriate UF (10x to account for interspecies differences and 10x for
intraspecies differences) the LOC is 100. To estimate risk, a ratio of
the NOAEL to exposures (margin of exposure (MOE) = NOAEL/exposure) is
calculated and compared to the LOC.
The linear default risk methodology (Q*) is the primary method
currently used by the Agency to quantify carcinogenic risk. The Q*
approach assumes that any amount of exposure will lead to some degree
of cancer risk. A Q* is calculated and used to estimate risk which
represents a probability of occurrence of additional cancer cases
(e.g., risk is expressed as 1 x 10^-6 or one in a million).
Under certain specific

[[Page 51547]]

circumstances, MOE calculations will be used for the carcinogenic risk
assessment. In this non-linear approach, a ``point of departure'' is
identified below which carcinogenic effects are not expected. The point
of departure is typically a NOAEL based on an endpoint related to
cancer effects though it may be a different value derived from the dose
response curve. To estimate risk, a ratio of the point of departure to
exposure (MOEcancer = point of departure/exposures) is
calculated. The RfD approach is used when the chronic dietary risk
assessment using the RfD will be adequately protective for cancer risk
as well as other chronic effects. Therefore, with the RfD approach no
separate carcinogenic risk assessment is necessary. The doses and
toxicological endpoints selected and the LOC for margins of exposure
for various exposures scenarios are summarized in the following Table
1:

Table 1.--Summary of Toxicological Dose and Endpoints for Dimethenamid for Use in Human Risk Assessment
----------------------------------------------------------------------------------------------------------------
FQPA SF^* and level of
Exposure scenario Dose used in risk concern for risk Study and toxicological
assessment, UF assessment effects
----------------------------------------------------------------------------------------------------------------
Acute dietary females 13-50 years of NOAEL = 215 mg/kg/day; FQPA SF = 10x; aPAD = Developmental toxicity,
age UF = 100; Acute RfD = acute RfD rat; LOAEL is 425 mg/
2.15 mg/kg/day FQPA SF = 0.215 mg/kg/ kg/day based on early
day resorption.
----------------------------------------------------------------------------------------------------------------
Acute Dietary general population NOAEL = 215 mg/kg/day; FQPA SF = 10x aPAD = Developmental toxicity,
including infants and children UF = 100; Acute RfD = acute RfD rat; LOAEL is 425 mg/
2.15 mg/kg/day FQPA SF = 0.215 mg/kg/ kg/day based on early
day resorption.
----------------------------------------------------------------------------------------------------------------
Chronic dietary all populations NOAEL = 5.1 mg/kg/day; FQPA SF = 10x; cPAD = Chronic rat study;
UF = 100; Chronic RfD chronic RfD LOAEL is 36 mg/kg/day
= 0.05 mg/kg/day FQPA SF = 0.005 mg/kg/ (males) based on
day increased incidences
of non-neoplastic
alterations in liver,
parathyroid and
stomach of males and
ovary of females, as
well as decreased food
efficiency in females.
----------------------------------------------------------------------------------------------------------------
Short-Term dermal (1 to 7 days) None None None
(residential)
----------------------------------------------------------------------------------------------------------------
intermediate-Term dermal (1 week to None None None
several months) (residential)
----------------------------------------------------------------------------------------------------------------
long-Term dermal (several months to None None None
lifetime) (residential)
----------------------------------------------------------------------------------------------------------------
Short-Term Inhalation (1 to 7 days) None None None
(residential)
----------------------------------------------------------------------------------------------------------------
intermediate-Term Inhalation (1 week None None None
to several months) (residential)
----------------------------------------------------------------------------------------------------------------
long-Term Inhalation (several months None None None
to lifetime) (residential)
----------------------------------------------------------------------------------------------------------------
Cancer (oral, dermal, inhalation) NOAEL = 5.1 mg/kg/day; Category ``C'' Chronic rat study;
UF = 100; Chronic RfD (possible human increased tumor
= 0.05 mg/kg/day carcinogen) incidence only in rats
(not mice).
Significant increasing
dose-related trend in
combined benign and/or
malignant liver tumor
rates in males (not
significant pair-wise
comparison). In
females, significantly
increasing dose-
related trend in
ovarian adenomas (not
significant pair-wise
comparison). Incidence
at 80 mg/kg/day (HDT)
about twice the
average of historical
incidence.
Quantitative cancer
risk assessment not
required.
----------------------------------------------------------------------------------------------------------------
^* The reference to the FQPA Safety Factor refers to any additional safety factor retained due to concerns unique
to the FQPA.

B. Exposure Assessment

1. Dietary exposure from food and feed uses. Dimethenamid is
registered for use on various agricultural commodities. Tolerances have
been established (40 CFR 180.464) for the residues of dimethenamid, in
or on dry beans, corn, sweet corn, peanuts, sorghum and soybeans.
Currently, dimethenamid is not registered on any use sites which would
result in non-dietary, non-occupational exposure. Therefore, EPA
expects only dietary and occupational exposure will result from the use
of dimethenamid. Risk assessments were conducted by EPA to assess
dietary exposures from dimethenamid in food as follows:
i. Acute exposure. Acute dietary risk assessments are performed for
a food-

[[Page 51548]]

use pesticide if a toxicological study has indicated the possibility of
an effect of concern occurring as a result of a one day or single
exposure. The Dietary Exposure Evaluation Model (DEEM)
analysis evaluated the individual food consumption as reported by
respondents in the USDA 1989-1992 nationwide Continuing Surveys of Food
Intake by Individuals (CSFII) and accumulated exposure to the chemical
for each commodity. The following assumptions were made for the acute
exposure assessments: all residues occurred at tolerance levels and
100% of crops with dimethenamid tolerances were treated.
ii. Chronic exposure. In conducting this chronic dietary risk
assessment the DEEM analysis evaluated the individual food
consumption as reported by respondents in the USDA 1989-1992 nationwide
CSFII and accumulated exposure to the chemical for each commodity. The
following assumptions were made for the chronic exposure assessments:
all residues occurred at tolerance levels and that 100% of crops with
dimethenamid tolerances were treated.
iii. Cancer. Dimethenamid has been classified as a Category ``C''
(possible human carcinogen), based on increased tumor incidence only in
rats (not mice). The Agency determined that a quantitative cancer risk
assessment is not required. The RfD approach was used to estimate
cancer risk. Therefore the chronic (non-cancer) risk assessment is
adequate estimate of cancer risk as well as other chronic effects.
2. Dietary exposure from drinking water. The Agency lacks
sufficient monitoring exposure data to complete a comprehensive dietary
exposure analysis and risk assessment for dimethenamid in drinking
water. Because the Agency does not have comprehensive monitoring data,
drinking water concentration estimates are made by reliance on
simulation or modeling taking into account data on the physical
characteristics of dimethenamid.
The Agency uses the Generic Estimated Environmental Concentration
(GENEEC) or the Pesticide Root Zone/Exposure Analysis Modeling System
(PRZM/EXAMS) to estimate pesticide concentrations in surface water and
SCI-GROW, which predicts pesticide concentrations in groundwater. In
general, EPA will use GENEEC (a tier 1 model) before using PRZM/EXAMS
(a tier 2 model) for a screening-level assessment for surface water.
The GENEEC model is a subset of the PRZM/EXAMS model that uses a
specific high-end runoff scenario for pesticides. GENEEC incorporates a
farm pond scenario, while PRZM/EXAMS incorporate an index reservoir
environment in place of the previous pond scenario. The PRZM/EXAMS
model includes a percent crop area factor as an adjustment to account
for the maximum percent crop coverage within a watershed or drainage
basin.
None of these models include consideration of the impact processing
(mixing, dilution, or treatment) of raw water for distribution as
drinking water would likely have on the removal of pesticides from the
source water. The primary use of these models by the Agency at this
stage is to provide a coarse screen for sorting out pesticides for
which it is highly unlikely that drinking water concentrations would
ever exceed human health levels of concern.
Since the models used are considered to be screening tools in the
risk assessment process, the Agency does not use estimated
environmental concentrations (EECs) from these models to quantify
drinking water exposure and risk as a %RfD or %PAD. Instead, drinking
water levels of comparison (DWLOCs) are calculated and used as a point
of comparison against the model estimates of a pesticide's
concentration in water. DWLOCs are theoretical upper limits on a
pesticide's concentration in drinking water in light of total aggregate
exposure to a pesticide in food, and from residential uses. Since
DWLOCs address total aggregate exposure to dimethenamid they are
further discussed in the aggregate risk sections below.
Based on the GENEEC and SCI-GROW models the estimated environmental
concentrations (EECs) of dimethenamid in surface water and ground
water, for acute exposures are estimated to be 63.5 parts per billion
(ppb) for surface water and 0.412 ppb for ground water. The EECs for
chronic exposures are estimated to be 17 ppb for surface water and
0.412 ppb for ground 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). Dimethenamid is not
registered for use on any sites that would result in residential
exposure.
4. Cumulative exposure to substances with a common mechanism of
toxicity. Section 408(b)(2)(D)(v) 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 does not have, at this time, available data to determine
whether dimethenamid has a common mechanism of toxicity with other
substances or how to include this pesticide in a cumulative risk
assessment. Unlike other pesticides for which EPA has followed a
cumulative risk approach based on a common mechanism of toxicity,
dimethenamid does not appear to produce a toxic metabolite produced by
other substances. For the purposes of this tolerance action, therefore,
EPA has not assumed that dimethenamid has 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 the final rule
for Bifenthrin Pesticide Tolerances November 26, 1997, (62 FR 62961)
(FRL-5754-7).

C. Safety Factor for Infants and Children

1. Safety factor for infants and children--i. In general. FFDCA
section 408 provides that EPA shall apply an additional tenfold margin
of safety for infants and children in the case of threshold effects to
account for pre-natal and post-natal toxicity and the completeness of
the data base on toxicity and exposure unless EPA determines that a
different margin of safety will be safe for infants and children.
Margins of safety are incorporated into EPA risk assessments either
directly through use of a MOE analysis or through using uncertainty
(safety) factors in calculating a dose level that poses no appreciable
risk to humans.
ii. Developmental toxicity studies. In a developmental toxicity
study in rats, maternal toxicity was evidenced by excessive salivation,
increased liver weight and reduced body weight gain and food
consumption at 215 and 425 milligrams per kilogram per day (mg/kg/day).
Developmental toxicity was evidenced by an increased incidence of
resorption in the 425 mg/kg/day rats. The maternal NOAEL is 50 mg/kg/
day and the maternal LOAEL is 215 mg/kg/day. The developmental NOAEL is
215 mg/kg/day and the developmental LOAEL is 425 mg/kg/day.
In a developmental toxicity study in rabbits, maternal toxicity was
evidenced by decreased body weight, food consumption and increased
abortion/premature delivery at 75 and 150 mg/

[[Page 51549]]

kg/day. Developmental toxicity was evidenced by increased abortion/
premature delivery and hyoid alae angulated changes in the 150 mg/kg
group. The maternal NOAEL is 37.5 mg/kg/day and the maternal LOAEL is
75 mg/kg/day. The developmental NOAEL is 75 mg/kg/day and the
developmental LOAEL is 150 mg/kg/day.
iii. Reproductive toxicity study. In a 2-generation reproductive
study in rats, parental toxicity was evidenced by significant
reductions in body weight and food consumption in males and significant
increases in absolute and relative liver weights in both sexes.
Significant reductions in pup weight during lactation occurred at 150
mg/kg/day. The parental NOAEL is 36 mg/kg/day and the parental LOAEL is
150 mg/kg/day. The reproduction NOAEL is 36 mg/kg/day and the
reproduction LOAEL is 150 mg/kg/day.
iv. Conclusion. Based on the rat and rabbit developmental toxicity
studies as well as the rat reproduction study, there did not appear to
be an increase in the sensitivity of fetuses or offspring in relation
to either maternal or parental toxicity. However, for purposes of these
section 18 uses, the additional FQPA 10x safety factor was retained
since the Agency's FQPA Safety Factor Committee has not assessed
dimethnamid at this time.

D. Aggregate Risks and Determination of Safety

To estimate total aggregate exposure to a pesticide from food,
drinking water, and residential uses, the Agency calculates DWLOCs
which are used as a point of comparison against the model estimates of
a pesticide's concentration in water (EECs). DWLOC values are not
regulatory standards for drinking water. DWLOCs are theoretical upper
limits on a pesticide's concentration in drinking water in light of
total aggregate exposure to a pesticide in food and residential uses.
In calculating a DWLOC, the Agency determines how much of the
acceptable exposure (i.e., the PAD) is available for exposure through
drinking water e.g., allowable chronic water exposure (mg/kg/day) =
cPAD - (average food + chronic non-dietary, non-occupational exposure).
This allowable exposure through drinking water is used to calculate a
DWLOC.
A DWLOC will vary depending on the toxic endpoint, drinking water
consumption, and body weights. Default body weights and consumption
values as used by the USEPA Office of Water are used to calculate
DWLOCs: 2L/70 kg (adult male), 2L/60 kg (adult female), and 1L/10 kg
(child). Default body weights and drinking water consumption values
vary on an individual basis. This variation will be taken into account
in more refined screening-level and quantitative drinking water
exposure assessments. Different populations will have different DWLOCs.
Generally, a DWLOC is calculated for each type of risk assessment used:
acute, short-term, intermediate-term, chronic, and cancer.
When EECs for surface water and groundwater are less than the
calculated DWLOCs, OPP concludes with reasonable certainty that
exposures to dimethenamid in drinking water (when considered along with
other sources of exposure for which OPP has reliable data) would not
result in unacceptable levels of aggregate human health risk at this
time. Because OPP considers the aggregate risk resulting from multiple
exposure pathways associated with a pesticide's uses, levels of
comparison in drinking water may vary as those uses change. If new uses
are added in the future, OPP will reassess the potential impacts of
dimethenamid on drinking water as a part of the aggregate risk
assessment process.
1. Acute risk. Using the exposure assumptions discussed in this
unit for acute exposure, the acute dietary exposure from food to
dimethenamid will occupy less than 1% of the aPAD for the U.S.
population, less than 1% of the aPAD for females 13 years and older,
less than 1% of the aPAD for all infants and less than 1% of the aPAD
for all children. In addition, despite the potential for acute dietary
exposure to dimethenamid in drinking water, after calculating DWLOCs
and comparing them to conservative model estimated environmental
concentrations of dimethenamid in surface and ground water. EPA does
not expect the aggregate exposure to exceed 100% of the aPAD, as shown
in the following Table 2:

Table 2.-- Aggregate Risk Assessment for Acute Exposure to Dimethenamid
----------------------------------------------------------------------------------------------------------------
Surface Ground
Population subgroup aPAD (mg/ % aPAD (Food) water EEC water EEC Acute DWLOC
kg) (ppb) (ppb) (ppb)
----------------------------------------------------------------------------------------------------------------
U.S. Population 0.215 Less than 1% 65.5 0.412 7,500
Females (13-19 years old) 0.215 Less than 1% 65.5 0.412 6,500
All Infants 0.215 Less than 1% 65.5 0.412 2,200
----------------------------------------------------------------------------------------------------------------

2. Chronic risk. Using the exposure assumptions described in this
unit for chronic exposure, EPA has concluded that exposure to
dimethenamid from food will utilize less than 1% of the cPAD for the
U.S. population, 2% of the cPAD for non-nursing infants (the most
highly exposed infant subpopulation) and 1% of the cPAD for children 1-
6 years old (the most highly exposed children subpopulation). There are
no registered residential uses for dimethenamid. In addition, despite
the potential for chronic dietary exposure to dimethenamid in drinking
water, after calculating the DWLOCs and comparing them to conservative
model estimated environmental concentrations of dimethenamid in surface
and ground water. EPA does not expect the aggregate exposure to exceed
100% of the cPAD, as shown in the following Table 3.

Table 3.-- Aggregate Risk Assessment for Chronic (non-Cancer) Exposure to Dimethenamid
----------------------------------------------------------------------------------------------------------------
Surface Ground
Population subgroup cPAD mg/kg/ % cPAD (Food) water EEC Water EEC Chronic
day (ppb) (ppb) DWLOC (ppb)
----------------------------------------------------------------------------------------------------------------
U.S. population 0.005 Less than 1% 17 0.412 180
Non-Nursing infants 0.005 2% 17 0.412 50
Children, 1-6 years old 0.005 1% 17 0.412 49
----------------------------------------------------------------------------------------------------------------

[[Page 51550]]

3. Short-term risk. Short-term aggregate exposure takes into
account residential exposure plus chronic exposure to food and water
(considered to be a background exposure level). Dimethenamid is not
registered for use on any sites that would result in residential
exposure. Therefore, the aggregate risk is the sum of the risk from
food and water, which were previously addressed.
4. Intermediate-term risk. intermediate-term aggregate exposure
takes into account non-dietary, non-occupational exposure plus chronic
exposure to food and water (considered to be a background exposure
level). Dimethenamid is not registered for use on any sites that would
result in residential exposure. Therefore, the aggregate risk is the
sum of the risk from food and water, which were previously addressed.
5. Aggregate cancer risk for U.S. population. Dimethenamid has been
classified as a Category ``C'' (possible human carcinogen). Based on
increased tumor incidence only in rats (not mice). The Agency
determined that a quantitative cancer risk assessment is not required.
The RfD approach was used to estimate cancer risk. Therefore, the
chronic (non-cancer) risk assessment, which was previously addressed,
is adequately protective for cancer risk as well as other chronic
effects.
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,and to infants and children from aggregate
exposure to dimethenamid residues.

V. Other Considerations

A. Analytical Enforcement Methodology

Adequate analytical methodology is available to enforce the
tolerance expression. Nitrogen Phosphorus Detection-Gas Liquid
Chromatography (NPD-GLC) method (AM-0884-0193-1) has been submitted (7/
89) for publication in the Pesticide Analytical Manual, Volume II, to
enforce tolerances for residues of dimethenamid in/on plant and soil
samples. The method may be requested from: Calvin Furlow, PRRIB, IRSD
(7502C), Office of Pesticide Programs, Environmental Protection Agency,
1200 Pennsylvania Ave., NW, Washington, DC 20460; telephone number:
(703) 305-5229; e-mail address: furlow.calvin@epa.gov.

B. International Residue Limits

There are no established Codex, Mexican, or Canadian maximum
residue limits for dimethenamid in/on onions, dry bulb and sugar beet,
tops and sugar beet, roots.

C. Conditions

A 30-day pre-harvest interval will be observed for dry bulb onions.
No pre-harvest interval is required for sugar beets due to the timing
of the applications.

VI. Conclusion

Therefore, the tolerance is established for residues of
dimethenamid, 2-chloro-N-[(1-methyl-2-methoxy)ethyl]-N-(2,4-
dimethylthien-3-yl)-acetamide, in or on dry bulb onions at 0.01 ppm,
sugar beets roots and tops at 0.01 ppm and sugar beet dry pulp and
molasses at 0.05 ppm.

VII. Objections and Hearing Requests

Under section 408(g) of the FFDCA, as amended by the FQPA, any
person may file an objection to any aspect of this regulation and may
also request a hearing on those objections. The EPA procedural
regulations which govern the submission of objections and requests for
hearings appear in 40 CFR part 178. Although the procedures in those
regulations require some modification to reflect the amendments made to
the FFDCA by the FQPA of 1996, EPA will continue to use those
procedures, with appropriate adjustments, until the necessary
modifications can be made. The new section 408(g) provides essentially
the same process for persons to ``object'' to a regulation for an
exemption from the requirementof a tolerance issued by EPA under new
section 408(d), as was provided in the old FFDCA sections 408 and 409.
However, the period for filing objections is now 60 days, rather than
30 days.

A. What Do I Need to Do to File an Objection or Request a Hearing?

You must file your objection or request a hearing on this
regulation in accordance with the instructions provided in this unit
and in 40 CFR part 178. To ensure proper receipt by EPA, you must
identify docket control number OPP-301038 in the subject line on the
first page of your submission. All requests must be in writing, and
must be mailed or delivered to the Hearing Clerk on or before October
23, 2000.
1. Filing the request. Your objection must specify the specific
provisions in the regulation that you object to, and the grounds for
the objections (40 CFR 178.25). If a hearing is requested, the
objections must include a statement of the factual issues(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).
Information submitted in connection with an objection or hearing
request may be claimed confidential 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. A copy of the
information that does not contain CBI must be submitted for inclusion
in the public record. Information not marked confidential may be
disclosed publicly by EPA without prior notice.
Mail your written request to: Office of the Hearing Clerk (1900),
Environmental Protection Agency, 1200 Pennsylvania Ave., NW.,
Washington, DC 20460. You may also deliver your request to the Office
of the Hearing Clerk in Rm. C400, Waterside Mall, 401 M St.,SW.,
Washington, DC 20460. The Office of the Hearing Clerk is open from 8
a.m. to 4 p.m., Monday through Friday, excluding legal holidays. The
telephone number for the Office of the Hearing Clerk is (202) 260-4865.
2. Tolerance fee payment. If you file an objection or request a
hearing, you must also pay the fee prescribed by 40 CFR 180.33(i) or
request a waiver of that fee pursuant to 40 CFR 180.33(m). You must
mail the fee to: EPA Headquarters Accounting Operations Branch, Office
of Pesticide Programs, P.O. Box 360277M, Pittsburgh, PA 15251. Please
identify the fee submission by labeling it ``Tolerance Petition Fees.''
EPA is authorized to waive any fee requirement ``when in the
judgement of the Administrator such a waiver or refund is equitable and
not contrary to the purpose of this subsection.'' For additional
information regarding the waiver of these fees, you may contact James
Tompkins by phone at (703) 305-5697, by e-mail at tompkins.jim@epa.gov,
or by mailing a request for information to Mr. Tompkins at Registration
Division (7505C), Office of Pesticide Programs, Environmental
Protection Agency, 1200 Pennsylvania Ave., NW., Washington, DC 20460.
If you would like to request a waiver of the tolerance objection
fees, you must mail your request for such a waiver to: James Hollins,
Information Resources and Services Division (7502C), Office of
Pesticide Programs, Environmental Protection Agency, 1200 Pennsylvania
Ave., NW., Washington, DC 20460.
3. Copies for the Docket. In addition to filing an objection or
hearing request with the Hearing Clerk as described in Unit VII.A., you
should also send a copy of your request to the PIRIB for its inclusion
in the official record that is described in Unit I.B.2. Mail your
copies, identified by the docket control number OPP-301038, to: Public

[[Page 51551]]

Information and Records Integrity Branch, Information Resources and
Services Division (7502C), Office of Pesticide Programs, Environmental
Protection Agency, 1200 Pennsylvania Ave., NW., Washington, DC 20460.
In person or by courier, bring a copy to the location of the PIRIB
described in Unit I.B.2. You may also send an electronic copy of your
request via e-mail to: opp-docket@epa.gov. Please use an ASCII file
format and avoid 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 6.1/8.0 file format or ASCII
file format. Do not include any CBI in your electronic copy. You may
also submit an electronic copy of your request at many Federal
Depository Libraries.

B. When Will the Agency Grant a Request for a Hearing?

A request for a hearing will be granted if the Administrator
determines that the material submitted shows the following: There is a
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 issues(s) in the manner sought
by the requestor would be adequate to justify the action requested (40
CFR 178.32).

VIII. Regulatory Assessment Requirements

This final rule establishes time limited tolerances under FFDCA
section 408. 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).
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., or impose any enforceable duty or contain any unfunded mandate as
described under Title II of the Unfunded Mandates Reform Act of 1995
(UMRA) (Public Law 104-4). Nor does it require any prior consultation
as specified by Executive Order 13084, entitled Consultation and
Coordination with Indian Tribal Governments (63 FR 27655, May 19,
1998); special considerations as required by Executive Order 12898,
entitled Federal Actions to Address Environmental Justice in Minority
Populations and Low-Income Populations (59 FR 7629, February 16, 1994);
or require OMB review or any Agency action under Executive Order 13045,
entitled Protection of Children from Environmental Health Risks and
Safety Risks (62 FR 19885, April 23, 1997). 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),
Public Law 104-113, section 12(d) (15 U.S.C. 272 note). Since
tolerances and exemptions that are established on the basis of a FIFRA
section 18 exemption under FFDCA section 408, such as the tolerances 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. In addition, the Agency has determined that this
action will not have a substantial direct effect on States, on the
relationship between the national government and the States, or on the
distribution of power and responsibilities among the various levels of
government, as specified in Executive Order 13132, entitled Federalism,
August 10, 1999 (64 FR 43255). Executive Order 13132 requires EPA to
develop an accountable process to ensure ``meaningful and timely input
by State and local officials in the development of regulatory policies
that have federalism implications.'' ``Policies that have federalism
implications'' is defined in the Executive Order to include regulations
that have ``substantial direct effects on the States, on the
relationship between the national government and the States, or on the
distribution of power and responsibilities among the various levels of
government.'' This final rule directly regulates growers, food
processors, food handlers and food retailers, not States. This action
does not alter the relationships or distribution of power and
responsibilities established by Congress in the preemption provisions
of FFDCA section 408(n)(4).

IX. Submission to Congress and the Comptroller General

The Congressional Review Act, 5 U.S.C. 801 et seq., as added by the
Small Business Regulatory Enforcement Fairness Act of 1996, generally
provides that before a rule may take effect, the agency promulgating
the rule must submit a rule report, which includes a copy of the rule,
to each House of the Congress and to the Comptroller General of the
United States. 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 this final rule in the Federal Register This final
rule 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.

August 15, 2000.
Peter Caulkins,
Acting Director, Registration Division, Office of Pesticide Programs.

Therefore, 40 CFR chapter I is amended as follows:

PART 180-- [AMENDED]

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

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

2. Section 180.464 is revised to read as follows:

Sec. 180.464 Dimethenamid, 2-chloro-N-[(1-methyl-2-methoxy)ethyl]-N-
(2,4-dimethylthien-3-yl)-acetamide

(a) General. Tolerances are established 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 following food
commodities:

------------------------------------------------------------------------
Parts per
Commodity million
------------------------------------------------------------------------
Beans, dry................................................. 0.01
Corn, fodder............................................... 0.01
Corn, forage............................................... 0.01
Corn, grain................................................ 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
Soybeans................................................... 0.01
------------------------------------------------------------------------

(b) Section 18 emergency exemptions. Time-limited tolerances are
established for residues of the herbicide dimethenamid in connection
with the use of the pesticide under section 18 emergency exemptions
granted by EPA. These tolerances will expire and are revoked on the
dates specified in the following table.

[[Page 51552]]

------------------------------------------------------------------------
Expiration/
Commodity Parts per revocation
million date
------------------------------------------------------------------------
Beet, sugar................................ 0.01 12/31/02
Beet, sugar, dried pulp.................... 0.05 12/31/02
Beet, sugar, molasses...................... 0.05 12/31/02
Beet, sugar, tops.......................... 0.01 12/31/02
Onion, dry bulb............................ 0.01 12/31/02
------------------------------------------------------------------------

[FR Doc. 00-21672 Filed 8-23-00; 8:45 am]
BILLING CODE 6560-50-S

Dimethenamid; Pesticide Tolerances for Emergency Exemptions

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