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fenaminosulf (Dexon) Chemical Fact Sheet 10/83

                        CHEMICAL FACT SHEET FOR:
                             FENAMINOSULF

FACT SHEET NUMBER:  10

DATE ISSUED:  OCTOBER 14, 1983


                      1.  DESCRIPTION OF CHEMICAL

- Generic Name:  p-(dimethylamino)benzenediazo sodium sulfonate
- Common Name:  fenaminosulf
- Trade Name:  Lesan, Dexon, Bayer 22555, Bayer 5072, diazoben
- EPA Shaughnessy Code:  034201
- Chemical Abstracts Service (CAS) Number:  140-56-7
- Year of Initial Registration:  1959
- Pesticide Type:  Fungicide
- Chemical Family:  Sulfonated phenyl diazo
- U.S. and Foreign Producer:  Mobay Chemical Corporation


                    2.  USE PATTERNS AND FORMULATIONS

- Application sites:  vegetables, ornamentals, lawns, and turf
- Types and methods of application:  dry or as a slurry, soil drench,
  foliar spray, or protectant seed treatment
- Application rates:  0.005 to 17 lb a.i./A on crop sites
- Types of formulations:  Available as a wettable powder, dust, and
  granular formulations (80% technical product  70,35,32, and 5% WP;
  2.5% D; 5 and 0.4% G)
- Usual carrier:  water


                          3.  SCIENCE FINDINGS

Chemical Characteristics

- Fenaminosulf is a yellowish-brown, odorless powder.  It is soluble in
  water (2-3% at 25 degrees C).  The chemical does not present any
  unusual handling hazards.


Toxicological Characteristics

- Chronic toxicology studies:
  - Mutagenicity:  positive results
  - Fenaminosulf is structurally related to the azo dyes that are
    known carcinogens
- Major routes of exposure:  dermal and inhalation from field uses


Physiological and Biochemical Behavioral Characteristics

- Mechanism of pesticidal action:  appears to inhibit mitochondrial
  function
- Metabolism and persistence in plants and animals:  There is no data
  on plant and animal metabolism or bioaccumulation potential.


Environmental Characteristics

- Absorption and leaching in basic soil types:  appears to degrade
  with a half-life of 2 days in soil
- Studies are inadequate to reach a final conclusion about the fate of
  fenaminosulf in the environment or the exposure potential of the
  chemical to humans and wildlife.


Ecological Characteristics

- Hazards to fish and wildlife:
  - Avian acute oral LD50:  13 mg/kg
  - Avian subacute dietary LC50:  250 ppm
  - Fish LC50:  >60 ppm
  - Aquatic invertebrates LC50:  Scuds 3.7 ppm; Stoneflies 24 ppm
- Potential problems for endangered species:  The use patterns do not
  present any problem to endangered species.


Tolerance Assessment

  There are no tolerances established for fenaminosulf residues in or on
  any crop or animal product.  When the chemical was first registered,
  seed treatments were considered non-food uses.  The Agency's current
  position is that seed treatments are considered food uses until data
  is submitted showing no uptake of the chemical or its degradates.
  Therefore, metabolic studies are needed to determine the residues of
  concern and if tolerances must be established.  If tolerances need to
  be established, additional data requirements may have to be met.


Problems Known to Have Occurred From Use of the Chemical

  (PIMS) There have been 21 cases of exposure reported from mixing,
  loading, or field reentry.  No exposures have resulted in fatality.


Summary Science Statement

  There are extensive data gaps for fenaminosulf.  No human
  toxicological hazards of concern, other than mutagenicity, have been
  identified in studies reviewed by the Agency for the standard.  The
  Agency has no information that indicates continued use will result
  in any unreasonable adverse effects to man or his environment during
  the time required to develop the data.


           4.  SUMMARY OF REGULATORY POSITION AND RATIONALE

Use classification:  general


               5.  SUMMARY OF MAJOR DATA GAPS

- Product Chemistry:  studies due 5/84
  - Discussion of formation of ingredients
  - Preliminary analysis
  - Analytical methods
  - Certification of limits
  - Physical and chemical characteristics
- Residue Chemistry:  studies due 11/87
  - Plant residue
  - Animal residue
  - Meat/milk/poultry/eggs residue
- Environmental Fate:  studies due 11/87
  - Hydrolysis
  - Photodegradation
  - Aerobic metabolism
  - Leaching and absorption/desorption
  - Dissipation
  - Fish accumulation
- Toxicology:  studies due 11/87
  - Primary eye irritation - rabbit
  - Primary dermal irritation
  - Dermal sensitization
  - Acute Oral LD50 - rat
  - Acute Dermal LD50 - rat
  - Acute Inhalation LC50
  - 21-day dermal
  - Chronic toxicity - 2 species
  - Oncogenicity - 2 species
  - Teratogenicity - 2 species
  - Reproduction, 2 generation
  - Gene mutation
  - Chromosomal aberration
  - General metabolism
- Wildlife and Aquatics:  studies due 11/87
  - Avian dietary - upland game
  - Acute LC50 - invertebrates


                     6.  CONTACT PERSON AT EPA

Mr. Henry M. Jacoby (PM-21)
Environmental Protection Agency
Fungicide-Herbicide Branch (TS-767C)
401 M St., S.W.
Washington, DC  20460
(703) 557-1900


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.