thiophanate ethyl (Topsin, Cleary's 3336) Chemical Fact Sheet 2/86
CHEMICAL FACT SHEET FOR:
FACT SHEET NUMBER: 84
DATE ISSUED: FEBRUARY, 1986
1. DESCRIPTION OF CHEMICAL
- Generic name: Diethyl 4,4 '-o-phenylenebis[3-thioallophanate]
- Common name: Thiophanate, thiophanate ethyl
- Trade name: Topsin, Cleary'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
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
handheld equipment such as compressed air sprayers, hose and sprayers,
spray guns or possibly sprinkling cans or by boom sprayers mounted
from a tractor or trailer pulled by a tractor.
- Application rates: 6 to 10.9 lb/ai/A for turf uses and 0.25 to 0.75
lb ai for per 100 gallons for ornamental uses.
- Usual carriers: Water
3. SCIENCE FINDINGS
- Technical thiophanate 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.
- Acute toxicity studies indicate that thiophanate ethyl has moderate
to low acute toxicity to humans.
- Acute inhalation: LC50 = 6.7 mg/l (Tox Category III)
- Acute dermal: LD5 > 15,000 mg/kg (Tox Category III)
- Primary skin irritation: Non-irritating (Tox Category III)
- Acute oral: LD50 15,000 mg/kg (Tox Category IV)
- Primary eye irritation: Non-irritating (Tox Category 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.
Physiological and Biochemical Behavioral Characteristics
- Thiophanate 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.
- The environmental fate and transport of and the potential exposure
to thiophanate ethyl cannot be characterized until the required
environmental fate data are submitted.
- Thiophanate ethyl has extremely low toxicity to birds with an avian
dietary LC50 greater than 5620 ppm and avian oral LD50 greater than
2510 mg/kg. Thiophanate ethyl has moderate toxicity to fish and
aquatic invertebrates with a fish LC50 of 2.26 to 2.6 ppm and an
aquatic invertebrate LC50 of 2.6 ppm.
- To date there have been no U.S. tolerances or registrations on
food/feed items for thiophanate ethyl.
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 thiophanate 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.
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
- The available data are insufficient to indicate that any of the
risk criteria set forth in 40 CFR 162.11 (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 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
- 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
- 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
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
treatment plant authority. For guidance, contact your State
Water Board or Regional Office of the Environmental Protection
- End-Use Product Statements:
- The following environmental hazard statement must appear on all
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.
- The following feeding/grazing restriction statement must appear
on all EP products:
Do not graze treated areas pr 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 (dune 1986)
- Environmental Fate:
- Hydrolysis (dune 1986)
- Photodegradation (June 1986)
- Metabolism (December 1987)
- Mobility studies (June 1986)
- Soil dissipation studies (December 1986)
- Fish accumulation studies (June 1986)
- 21-day dermal (June 1986)
- Teratogenicity (September 1986)
- Mutagenicity testing (dune 1986)
- Wildlife and Aquatic Organisms:
- Freshwater fish and freshwater invertebrates acute toxicity
6. CONTACT PERSON AT EPA
Henry M. Jacoby
Product Manager (21)
401 M St., S.W.
Washington, D.C. 20460
DISCLAIMER: THE INFORMATION PRESENTED IN THIS CHEMICAL INFORMATION FACT
SHEET IS FOR INFORMATIONAL PURPOSES ONLY AND NOT TO BE USED TO FULFILL
DATA REQUIREMENTS FOR PESTICIDE REGISTRATION AND REREGISTRATION.