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thiophanate ethyl (Topsin, Cleary's 3336) Chemical Fact Sheet 2/86

                         CHEMICAL FACT SHEET FOR:
                             Thiophanate Ethyl

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
  Corp.


                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

Chemical Characteristics

- 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.


Toxicology Characteristics

- 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.


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 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.


Tolerance Assessment

- 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
  following determinations:
  - 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
    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
        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.

  - 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)

- Toxicology:
  - 21-day dermal (June 1986)
  - Teratogenicity (September 1986)
  - Mutagenicity testing (dune 1986)

- Wildlife and Aquatic Organisms:
  - Freshwater fish and freshwater invertebrates acute toxicity
    (September 1986)


                   6.  CONTACT PERSON AT EPA

Henry M. Jacoby
Product Manager (21)
EPO (TS-767C)
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.