United States Prevention, Pesticides EPA-738-F-99-011
Environmental Protection And Toxic Substances December 1999
Agency (7508C)
R.E.D. FACTS
EPIC
Pesticide All pesticides sold or distributed in the United States must be registered
Reregistration ty EPA> based on scientific studies showing that they can be used without
posing unreasonable risks to people or the environment. Because of advances
in scientific knowledge, the law requires that pesticides which were first
registered before November 1, 1984, be reregistered to ensure that they meet
today's more stringent standards.
In evaluating pesticides for reregistration, EPA obtains and reviews a
complete set of studies from pesticide producers, describing the human health
and environmental effects of each pesticide. To implement provisions of the
Food Quality Protection Act of 1996, EPA considers the special sensitivity of
infants and children to pesticides, as well as aggregate exposure of the public
to pesticide residues from all sources, and the cumulative effects of pesticides
and other compounds with common mechanisms of toxicity. The Agency
develops any mitigation measures or regulatory controls needed to effectively
reduce each pesticide's risks. EPA then reregisters pesticides that meet the
safety standard of the FQPA and can be used without posing unreasonable
risks to human health or the environment.
When a pesticide is eligible for reregistration, EPA explains the basis for
its decision in a Reregistration Eligibility Decision (RED) document. This fact
sheet summarizes the information in the RED document for reregistration case
0064, EPTC (S-Ethyl dipropylthiocarbamate).
The following active ingredient is covered by this Fact Sheet:
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Use Profile
Common Name:
Chemical Name:
Chemical Family:
Type of Chemical:
CAS Registry Number.
OFF Chemical Code:
Empirical Formula:
Basic Manufacturer:
EPIC
S-Ethyl dipropylthiocarbamate
Thiocarbamate
Herbicide
759.94-4
041401
Zeneca Ag Products
Regulatory History
EPIC is a pre-emergence and early post-emergence thiocarbamate
herbicide used to control the growth of germinating annual weeds, including
broadleaves, grasses, and sedges. It is used in every region of the United
States in the agricultural production of a wide variety of food crops. The
heaviest usage is in the Corn Belt, Northeastern and Mid-Atlantic states,
Coastal and Northern Great Plains and in the Pacific Northwest. Highest use
states are California, Michigan, Oregon, Pennsylvania, North Dakota,
Minnesota, and Arizona. The largest markets in terms of total pounds of
active ingredient are corn, potatoes, dry beans, peas, alfalfa, and snap beans.
Usage ranges from about 10 to 20 million pounds a.i. annually. EPTC is also
available to the residential home gardener for use in vegetable and ornamental
gardens.
As with other thiocarbamate herbicides, EPTC exerts its herbicidal action
through inhibition of cuticle formation at the early stages of seedling growth.
Formulated products include emulsifiable concentrate (EC) liquids containing
up to 87.8% active ingredient and granular (G) formulations containing up to
25% active ingredient. EPTC is typically applied annually in one to three
applications, with each application ranging from about 2 to 6.1 Ibs a.i./acre
(maximum rate 7.5 to 12.2 Ibs a.i./acre for alfalfa and potatoes). EPTC can
either be applied by aerial or ground equipment or through chemigation.
Because of its chemical properties, however it is applied, it must be
incorporated into the soil immediately after application to prevent
volatilization.
EPTC was registered in the United States in 1958 for use as a selective
preemergent herbicide, and was originally owned by Stauffer Chemical
Company. Chemiolimpex, a technical EPTC (TGAI), was manufactured in
Hungary, and was imported into the United States by PPG Industries of
Pittsburgh, Pennsylvania. Zeneca Ag Products currently holds registrations for
several end-use products, and holds the only registration for the technical
product.
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A Registration Standard for EPTC was issued in September 1993. The
Agency determined that additional generic data would have to be submitted for
evaluation in order to maintain registration. This RED reflects a reassessment
of all data which were submitted in response to the Registration Standard.
Human Health Toxicity results of acute toxicity, primary eye and dermal irritation, and
Assessment dermal sensitization studies with EPTC technical material are summarized in
the RED. EPTC is moderately toxic (Toxicity Category ffl) via the oral and
dermal routes, and in a primary eye irritation study in rabbits, the technical
was found to be slightly irritating (Toxicity Category m). EPTC is most toxic
via the inhalation route (Toxicity Category n).
There was an increased incidence and severity of cardiomyopathy and
neuronal necrosis/degeneration in studies performed in the central and
peripheral nervous systems of both rats and dogs. The neurotoxic effects of
EPTC are consistent with effects seen in other thiocarbamates. Because of
these effects (neuronal necrosis/degeneration), and the potential for residential
exposure to infants and children from use of EPTC, the Agency's FQPA
Safety Factor Committee recommended that the 1 Ox FQPA safety factor be
retained for all population subgroups for acute, chronic.and residential
exposure assessments.
Although it appears that EPTC did not produce any significant
reproductive or developmental toxicity, there is still uncertainty regarding the
effects on the developing fetal nervous system This uncertainty is being
addressed by the requirement of a developmental neurotoxicity study in rats.
EPTC effects were also negative in two oncogenicity studies.
Occupational and Residential Exposure
Occupational and residential exposure to EPTC residues via dermal and
inhalation routes can occur during handling activities such as mixing, loading,
and applying; however, the potential for postapplication occupational exposure
is minimal. Because EPTC is applied as a soil directed spray and immediately
incorporated, or as a soil injection well before plants are mature, the potential
for postapplication dermal exposure during harvest activities is minimal. In
addition, there is a potential for inadvertent oral exposure to children from
eating EPTC-treated soil and/or granules. Based on lexicological criteria and
potential for exposure, the Agency has conducted dermal and inhalation
exposure assessments for the occupational and residential handler, and for
residential postapplication inadvertent oral ingestion soil/granulars exposure to
children.
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Potential EPIC residential use sites may include a variety of shade trees,
evergreens, and annual or perennial ornamentals. EPIC is typically appked
only to bare soil once before planting or after weeding under ornamentals
followed by soil incorporation. Examples of typical usage of a granular
formulation in the home garden would include pre-planted application and
incorporation with a rototiller, post-plant application incorporated into the
soils to a depth of 2-3 inches using a hand rake or hoe, and weed contro in
established trees and shrubs by incorporation into the top 6 inches of soil In
contrast to occupational workers, individuals in residential settings are more
likely to transplant seedlings and plant seeds by hand. In addition, the«>*> a
potential for inadvertent oral exposure to children from eating EPTC-treated
soil and/or granules.
Human Risk Assessment
nistarv Exposure
Risk from food and water combined are acceptable. And the Tier 1
acute dietary exposure analysis of EPIC, exposure (food consumption) was
compared to an acute population adjusted dose of 0.067 mg/kg/day. The acute
dietanr risk analysis estimates the distribution of single day exposures for the
overall US population and certain subgroups. The analysis evaluates
exposure to the chemical for each food commodity, and assumes uniform
distribution of EPTC in the food supply.
The acute dietary residue contribution at the 95* percentile occupied less
than 100% of the aPAD for any population subgroup, and therefore does not
exceed the Agency's level of concern. For non-probalistic acute dietary
exposuretheAgencyusestheQS^percentile. *"*'™*^l*^
subgroup, children 1-6, residue contribution occupied 87.5% of the aPAD.
This Tier 1 acute analysis for EPTC is a conservative upper-bound estimate
with all input residues equal to the reassessed tolerance value and the
assumption that 100% of the crop is treated nationwide.
Fnvironmental Fate
The environmental fate data indicates that EPTC would not be persistent
under many environmental conditions, which is supported by relatively short
half-lives observed in terrestrial and low aquatic concentrations. Monitoring
data suggests that concentrations of EPTC in ground water will be less than
those found in surface water. However, the persistence of EPTC in ground
water would probably be greater than in surface water because losses due to
volatilization would.be expected to be much less.
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The low affinity for binding to soil and water solubility also suggest a
potential to leach, but since EPTC generally does not persist long in surface
soils, the potential to leach is greatly reduced.
Environmental Ecological Effects
Assessment
EPTC is practically non-toxic to birds and bees; slightly toxic to
mammals and fish, and moderately toxic to aquatic invetebrates, algae and an
aquatic vascular plant. Toxicity studies are unavailable for estuarine species.
Reproduction studies are not available for any species, except laboratory
mammals. Due to lack of data, acute risks to estuarine species, and
reproductive risks to birds, fish and aquatic invertebrates were not assessed.
The registrant will be required to provide additional data in order to evaluated
the potential effects of bird, aquatic and estuarine species.
EPTC is toxic to both monocot and dicot plant species. Although EPTC
is a pre-emergent herbicide, it may cause some phytotoxic damage and growth
effects on established plants. Risk quotients for granular and spray
applications suggest that EPTC poses adverse effects on non-target plants for
all uses.
Environmental Risk Characterization
Residue levels of EPTC on vegetation exceed levels of concern for high
acute risks and effect on endangered species for small mammals. Soil
incorporation reduces the amount of vegetation exposed, but the vegetation
remaining at the surface poses a potential risk to small mammals. Given the
low probability of EPTC dietary exposure to small mammals, any mortality is
unlikely to have any serious effect on the local populations of small mammals,
with the exception of an endangered species.
The level of concern is exceeded for endangered and terrestrial plants
species such as monocots and dicots. Non-target terrestrial plants in adjacent
fields or habitats are potentially at risk from spray drift from some uses and
from runoff for all registered uses. EPTC also appears to have the potential to
be transported off site via the vapor phase as it was one of a number of
residues found in more than 25 percent of the rain samples collected in three
water sheds in Minnesota. In addition, being a herbicide, EPTC may also have
an indirect effect on endangered insects by adversely affecting the plants on
which they depend.
The levels of EPTC that are likely to be atmospherically deposited into
soils or on vegetation is uncertain. The absence of reported atmospheric
deposition incidences does not preclude the occurrence of such events. The
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registrant will be required to provide additional data on field volatility and
atmospheric dissipation in order to further evaluate the environmental fate of
EPTC.
Although the EPTC data base is sufficient to render a reregistration
..eligibility decision, additional confirmatory data such as developmental
neurotoxicity, residue analytical methods-plant, and Multiresidue method
studies are needed to further assess the chemical's toxicity. In addition,
ecological effects and environmental fate studies are needed to fully assess the
impact of EPTC and its primary degradates on the environment.
T>{*L-M •*;,. *{ To lessen the risks posed by EPTC, EPA is requiring the following risk
KISK Mitigation mitigation measures:
The exposure assessments indicate that occupational handlers are at risk
to dermal and inhalation exposure, and that additional protective
measures are necessary to reduce these risks. Therefore, various forms
of additional personal protective equipment (PPE) (e.g., double layer
clothing and respirators) and engineering controls (e.g., enclosed
cockpits) are necessary for certain handler scenarios to reduce the risks
to below the Agency's level of concern.
In order to mitigate risks to homeowners, the registrant will be required
to add label language which prohibit use of the belly grinder, which
contributes to the highest level of exposure, for home owner products.
The registrant will also be required to delete all residential emulsifiable
concentrate formulation uses from the EPTAM 7E label. In addition,
the registrant will be required to change the maximum rate of 15 Ibs per
acre for the Eptam 2.3 granular products to the typical rate of 5 Ibs per
acre for residential products.
Risk quotients for granular and spray applications suggest that EPTC
poses adverse effects to small herbivorous and insectivorous mammals
for most uses and adverse effects on non-target terrestrial plants for all
uses. EPTC use could also cause adverse effects on endangered species.
As a member of the Endangered Species Task Force, the registrant will
be required to obtain information which identifies endangered and
threatened species of concern which may be found in areas adjacent to
crops treated with EPTC.
Additional Data EPA is requiring the following additional generic studies for EPTC to
Required confirm its regulatory assessments and conclusions.
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Guideline: Study;
870.6300 Developmental neurotoxicity study in the rat
860.1340 Residue Analytical methods-Plant
860.1360 Multiresidue Method
860.1380 Storage Stability Data
860.1520 Processed Food/ Feed
860.1500 Crop field Trials
Guideline: Study;
850.2100 Acute Avian Oral (quail/duck)
850.2300 Avian Reproduction (quail/duck)
850.1010 Invertebrate toxicity
850.1025 Estu/mari tox mollusk
850.1035 Estu/mari tox shrimp
850.1045 Estu/mari tox fish
850.1300 Life cycle invertebrate
835.4300 Aerobic Aquatic Metabolism
835.8100 Field Volatility
835.1240 Leach/adsorption/deportation
Product Labeling Before reregistering the products containing EPTC, the Agency is
Changes Required requiring that product specific data, revised Confidential Statements of
Formula (CSF), and revised labeling be submitted within eight months of the
issuance of this document. These data include product chemistry for each
registration and acute toxicity testing. After reviewing these data and any •
revised labels and finding them acceptable in accordance with Section 3(c)(5)
of FTFRA, the Agency will reregister a product. Those products which contain
other active ingredients will be eligible for registration only when the other
active ingredients are determined to be eligible for reregistration. All EPTC
end-use products must comply with EPA's current pesticide product labeling
requirements and. For a comprehensive list of labeling requirements, please
see the EPTC RED document.
The use of currently registered products containing EPTC in
accordance with approved labeling will not pose unreasonable risks or adverse
effects to humans or the environment. Therefore, all uses of these products are
eligible for reregistration.
Regulatory EPA has determined that products containing EPTC are eligible for
Conclusion rere8istration. The use of eligible EPTC products in accordance with labeling
specified in this RED will not pose unreasonable adverse effects to humans or
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the environment. These products will be reregistered once the required
confirmatory generic data, product specific data, CSFs, and revised labeling are
received and accepted by EPA. Products which contain active ingredients in
addition to EPIC will be reregistered when all of their other active ingredients
also are eligible for registration.
For More E^A is requesting public comments on the Reregistration Eligibility
Information Decision (RED) document for EPIC during a 60-day time period, as
announced in a Notice of Availability published in the Federal Register. To
obtain a copy of the RED document or to submit written comments, please
contact the Pesticide Docket, Public Information and Records Integrity
Branch, Information Resources and Services Division (7502C), Office of
Pesticide Programs (OPP), US EPA, Washington, DC 20460, telephone 703-
305-5805.
Electronic copies of the RED and this fact sheet are available on the
Internet. See http://www.epa.gov/REDs. Printed copies of the RED and fact
sheet can be obtained from EPA's National Service Center for Environmental
Publications (EPA/NSCEP), PO Box 42419, Cincinnati, OH 45242-2419,
telephone 1-800-490-9198; fax 513-489-8695.
Following .the comment period, the EPTC RED document also will be
available from the National Technical Information Service (NTIS), 5285 Port
Royal Road, Springfield, VA 22161, telephone 703-605-6000.
For more information about EPA's pesticide reregistration program, the
EPTC RED, or reregistration of individual products containing EPTC, please
contact the Special Review and Reregistration Division (7508C), OPP, US
EPA, Washington, DC 20460, telephone 703-308-8000.
For information about the health effects of pesticides, or for assistance
in recognizing and managing pesticide poisoning symptoms, please contact the
National Pesticides Telecommunications Network (NPTN). Call toll-free
1-800-858-7378, from 6:30 am to 4:30 pm, Pacific Standard Time, or 9:30 am
to 7:30 pm, Eastern Standard Time, seven days a week.
Their internet address is ace.orst.edu/info/nptn.
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