United States Office of Pesticides and Toxic Substances
Environmental Protection Office of Pestiade Programs (TS-766C)
Agency Washington, DC 20460
&EPA Pesticide
Fact Sheet
Name Of Chemical: Thiophanate Ethyl
Reason for Issuance: W*ratlon Standard
Date Issued: February 1986
Fact Sheet Number: 84
1. Description of chemical
Generic name: Diethyl 4,4 '-o-phenylenebis[3-thioallophanate]
Common name: Thiophanate, thlophanate ethyl
Trade name: Topsin, deary's 3336, Cercobin
EPA Shaughnessy code: 103401
Chemical Abstracts Service (CAS) number: 23564-06-9
Year of Initial registration: 1973
Pesticide type: Fungicide
Chemical family: Thiophanate
U.S. and foreign producers: Nippon Soda Co., Ltd., Japan
Pennwalt Corporation
2. Use patterns and formulations
Application sites: turf (golf courses), roses, flowers, ornamentals,
and shade trees.
Formulations: Wettable powder, flowable concentrate.
Types and methods of application: Applied as a spray by means of hand-
held equipment such as compressed air sprayers, hose end sprayers, spray
guns or possibly sprinkling cans or by boom sprayers mounted from a
tractor or trailer pulled by a tractor.
Application rates: 1.36 to 10.9 Ib/ai/A for turf uses and 0.25 to 0.75
Ib ai for per 100 gallons for ornamental uses.
Usual carriers: water
3. Science findings
Summary science statement; Although no human toxicological hazards of
concern have been identified in studies reviewed by the Agency for the
standard, extensive environmental data gaps exist for thlophanate ethyl.
The Agency has no information that indicates continued use will result
in any unreasonable adverse effects to man or the environment during
the time required to develop the data.
Chemical characteristics; Technical thlophanate ethyl is a white to
pale brown crystalline powder with a faint sulfur odor. It has a
melting point of 191.7° C and a specific gravity of 1.44. It is stable
in acid and slightly decomposes in base.
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Toxicology Characteristics : Acute toxicity studies indicate
that thiophanate ethyl has moderate to low acute toxicity to
humans.
Study Results Toxicity Category
Acute inhalation LC 5 = 6.7 mg/L III
Acute dermal LD 5 ” > 15,000 mg/kg III
Primary skin irritation Non—irritating III
Acute oral LD 50 > 15,000 mg/kg IV
Primary eye irritation Non—irritating IV
Studies conducted in rats and mice indicate that
thiophanate ethyl is not oncogenic in laboratory animals.
No decision can be made concerning the teratogenic and mutagenic
potential of thiophanate ethyl until such studies are submitted
to the Agency.
Biochemical Behavioral Characteristics : Thiophariate ethyl
slowly converts to ethyl—2—benzimidazole carbamate (EBC) which
is considered to be the fungicidally active agent. The mode
of action of EBC involves its interference in the biosynthesis
of DNA in the fungal cell division process.
Environmental Characteristics : The environmental fate and
transport of and the potential exposure to thiophanate ethyl
cannot be characterized until the required environmental
fate data are submitted.
Ecological Characteristics : Thiophanate ethyl has extremely
low toxicity to birds with an avian dietary LC 50 greater
than 5620 ppm and avian oral LD5O greater than 2510 mg/kg.
Thiophanate ethyl has moderate toxicity to fish and aquatic
invertebrates with a fish LC 50 of 2.26 to 2.6 ppm and an
aquatic invertebrate LC 50 of 2.6 ppm.
Tolerance Reassessment : To date there have been no U.S.
tolerances or registrations on food/feed items for
thiophanate ethyl.
4. Summary of Regulatory Position and Rationale
Based on the review and evaluation of all available data
and other relevant information on thiophanate ethyl, the
Agency has made the following determinations:
The available data are insufficient to indicate that
any of the risk criteria set forth in 40 CFR 5162.11(a)
have been met or exceeded for the uses of thiophanate ethyl
at the present time. For example, (1) Thiophanate ethyl is
not oncogenic in rats or mice, (2) Potential exposure to the
active metabolite EBC from uses currently covered by the
standard does not raise concern at this time, and
(3) thiophanate ethyl has moderate to low acute toxicity to
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humans. The available data, however, are incomplete and no
decision concerning the teratogenicity, mutagenicity, or
environmental fate of thiophanate ethyl can be made until the
required data are submitted. Thiophanate ethyl has extremely
low toxicity to birds and moderate toxicity to fish and
aquatic invertebrates. Additional acute toxicity testing
with channel catfish is being required because the chemically
related compounds thiophanate methyl and benomyl are highly
toxic to the ictalurid (catfish) family. A detailed ecological
hazard assessment cannot be made until certain environmental
fate data requirements have been met.
End—use product (EP) labels will be required to bear a
revised environmental hazard statement.
EP labels will be required to maintain a grazing/feeding
restriction.
Manufacturing—use product (MP) labels will be required to
bear a statement regarding discharge to bodies of water
and sewer systems.
Specific label warning statements:
Hazard Information
The human hazard statements must appear on all labels
as prescribed in 40 CFR 162.10(h).
Environmental Hazard Statement
All MPs intended for formulation into EPs must bear
the following statements:
“Do not discharge effluent containing this product directly
into lakes, streams, ponds, estuaries, oceans or public
waters unless this product is specifically identified and
addressed in a National Pollutant Discharge Elimination
System (NPDES) permit. Do not discharge effluent
containing this product into sewer systems without
previously notifying the sewage treatment plant authority.
For guidance, contact your State Water Board or Regional
Office of the Environmental Protection Agency.”
End-Use Product Statements
The following environmental hazard statement must appear
on all EP products:
“Do not apply directly to water or wetlands (swamps, bogs,
marshes, and potholes). Do not contaminate water by
cleaning of equipment or disposal of wastes.”
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The following feeding/grazing restriction statement
must appear on all EP products:
“Do not graze treated areas or feed clippings to
livestock.”
5. Summary of Major Data Gaps and Dates for Submission
Product Chemistry
Product Identity (December 1986)
Analysis and Certification of Product Ingredients (June 1986)
Physical and Chemical Characteristics (June 1986)
Environmental Fate
Hydrolysis (June 1986)
Photodegradation (June 1986)
Metabolism (December 1987)
Mobility Studies (June 1986)
Soil Dissipation Studies (December 1987)
Fish Accumulation Studies (June 1986)
Toxicology
21—Day Dermal (June 1986)
Teratogenicity (September 1986)
Mutagenicity Testing (June 1986)
Wildlife and Aquatic Organisms
Freshwater Fish and Freshwater Invertebrates Acute
Toxicity (September 1986)
6. Contact Person at EPA
Henry M. Jacoby
EPA (TS—767C)
401 M. St., S.W.
Washington, D.C. 20460
DISCLAIMER: The information presented in this Pesticide Fact
Sheet is for informational purposes only and may not be used
to fulfill data requirements for pesticide registration and
reregistration.
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