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bensulide (Betasan, Prefar) Herbicide Profile 3/85

      CHEMICAL NAME:      [S-(O,O-diisopropyl phosphorodithioate)ester of
                          N-(2-mercaptoethyl)benzenesulfonamide] (58)
      TRADE NAME(S):      Betasan, Betamec, Exporsan, Prefar, Pre-San (56)
      FORMULATION(S):     Emulsifiable concentrate (4 lb/gal), granules
                          (12.5%, 7%, 3.6%) (56).
      TYPE:               Herbicide
      BASIC PRODUCER(S):  PBI-Gordon Corp.            Stauffer Chemical Co.
                          P.O. Box 4090               Agricultural Chem. Div.
                          Kansas City, MO 64101       Westport, CT 06881
      STATUS:             General use
      PRINCIPAL USES:  Betasan is registered for control of crabgrass,
      annual bluegrass, redroot pigweed, watergrass, lambsquarters,
      shepherdspurse, goosegrass, and deadnettle in grass and dichondra lawns.
      Prefar is registered for controlling various grass and broadleaf weeds in
      cotton, lettuce, cucumbers, cantaloupes, squash (summer and winter),
      Crenshaw and Persian melons, muskmelons, watermelons, tomatoes, peppers,
      broccoli, cabbage, and cauliflower (58).
      APPLICATION METHOD(S):  Betasan should be used prior to germination of
      weed seeds.  It should be applied to established grass lawns prior to
      planting, at the time of planting, or on established dichondra lawns.
      The compound must be watered into the soil after application.  Care
      should be exercised if reseeding with grass is planned following
      Prefar should be applied by preplant incorporation 2.5 to 5 cm (1-2
      inches) deep, or preemergence followed by sprinkler or furrow irrigation
                                   I.  EFFICACY
           Bensulide provides long residual control of the weeds for which it
      is registered (58).
      Important Weeds Controlled:
           Smooth and hairy crabgrass, watergrass, fall panicum, annual
      bluegrass, jungle rice, silver crabgrass, foxtail, pigweed, goosegrass,
      purslane, and others (8b).
                             II.  PHYSICAL PROPERTIES
      MOLECULAR FORMULA:  C14 H24 NO4 PS3 (62)
      MOLECULAR WEIGHT:   397.5 (62)
      PHYSICAL STATE:     Colorless solid (99% pure); amber solid or
                          supercooled liquid (technical grade, 98% pure)
      MELTING POINT:      34.4 C (99% pure) (62); supercools readily (pure
                          compound) (58).
      BOILING POINT:      Decomposes (Betasan technical) (29r).
      VAPOR PRESSURE:     0.001 microns at 25 C (Betasan technical) (29r).
      SOLUBILITY:         25 ppm in water at 20 C (Betasan technical) (29r).
                          III.  HEALTH HAZARD INFORMATION
           A.  ACUTE TOXICITY
               DERMAL:  Betasan technical:  LD50 in rabbits, approximately
                          4 g/kg.  Toxicity was not observed in rabbits at
                          1000 mg/kg.  Non-irritating to the skin of rabbits
                        Betasan 3.6-G:  The acute dermal LD50 is greater
                          than 5000 mg/kg in rabbits.  A single dermal
                          application of 5000 mg/kg produced a mild decrease
                          in physical activity in rabbits.  Nonirritant to
                          rabbit skin following a 24-hour exposure (29t).
                        Betasan 4-E:  The acute dermal LD50 is greater than
                          4640 mg/kg in rabbits.  A single dermal application
                          of 4640 mg/kg did not produce signs of toxicity in
                        Mild irritant to rabbit skin.
                        Application of 18 ml to rabbit skin (9.1 ml/kg),
                          caused plasma (53%) and erythrocyte (58%)
                          cholinesterase inhibition, 8-24 hours after
                          dosing.  A volume of 10 ml per animal (5.2 ml/kg)
                          did not cause any inhibition of erythrocyte
                        Rabbits received fifteen daily doses during a
                          three week period.  The doses were 0.5, 0.25 and 0.1
                          ml/kg/day.  Erythrocyte cholinesterase activity was
                          inhibited about 25-60 percent at the high dose
                          level.  Plasma cholinesterase was unaffected.
                          Pyelonephritis occurred in all treated groups.
                        Rabbits were treated once daily for a total of
                          12 doses during a three week period.  Doses were 2.0,
                          1.0 and 0.5 ml/kg.  Erythrocyte cholinesterase was
                          inhibited completely in all treated animals by the
                          first week and plasma cholinesterase was inhibited
                          by 40 to 60 percent (29s).
               ORAL:    LD50 = 271-1470 mg/kg.  Single oral exposures of
                          215 to 4649 mg/kg produced salivation, lacrimation,
                          urination, diarrhea, dyspnea, depression and
                          mortality (Betasan technical) (29n).
                        LD50 = 826-1778 mg/kg (rat, Betasan 4-E) (29s).
                        The acute oral LD50 is greater than 1000 mg/kg
                          in female and male rats.  A single oral dose of 1000
                          mg/kg produced a mild decrease in physical activity
                          in male and female rats (Betasan 3.6-G) (29t).
               INHALATION:  LC50 in rats, greater than 3.07 mg/l for 1-hour
                            exposure.  No signs of toxicity were observed at
                            3.07 mg/l (Betasan technical) (29r).
               EYES:    Mild to moderate irritant to rabbit eyes (Betasan
                        4-E) (29s).  Moderate irritant to rabbit eyes
                        (Betasan 3.6-G) (29t).
           Daily ingestion of 625, 1250 and 2500 ppm in the diet by dogs for 14
      weeks resulted in a no-effect level at 625 ppm, minimal hepatic
      cellular changes at 1250 ppm and reduced body weight, elevated serum
      enzyme levels and moderate degenerative hepatic changes at 2500 ppm.
           Daily ingestion of 4 and 12 mg/kg/day by dogs for 14 weeks resulted
      in moderate inhibition of plasma cholinesterase at 4 and 12 mg/kg.
           Daily ingestion of 20, 40, 80 160 and 320 mg/kg/day by mice for 6
      weeks resulted in decreased food consumption and body weight at 32 mg/kg.
           Daily ingestion of 10 and 30 mg/kg/day by mice and 100 mg/kg/day by
      female mice for 12 months was without observable effect.  Daily
      ingestion of 100 mg/kg/day by male mice for 12 months resulted in very
      slight to slight multi focal hepatocellular hypertrophy.
           Daily ingestion of 12.5, 25 and 50 mg/kg/day by rats for 14 weeks
      resulted in no significant changes at 12.5 and 25 mg/kg, and slight
      hepatic and renal changes observed by histopathology at 50 mg/kg.
           Daily ingestion of 5 or 15 mg/kg/day by rats for 13 weeks resulted
      in transient inhibition of plasma cholinesterase.  Negative in
      bacterial mutagenicity assay without activation (Betasan technical)
                         IV.  ENVIRONMENTAL  CONSIDERATIONS
      Behavior In Or On Soils
      1.   Adsorption and leaching characteristics in basic soil types:
             Bensulide is inactivated in soils containing high amounts of
             organic matter.  Bensulide leaches very little in sand, clay
             or organic soils.
      2.   Microbial breakdown:  Bensulide is degraded slowly in the soil by
             soil microorganisms.a
      3.   Loss from photodecomposition and/or volatilization:  When applied
             to the soil surface there is very little if any loss bu
             volatilization, but there is a small amount of
             photodecomposition in a period of several days.
      4.   Resultant average persistence at recommended rates:  The half life
             in moist loam soil at 21 to 27 C (70 to 80 F) was 4 months.
             In a moist loamy sand soil at 21 to 27 C (70 to 80F) the half
             life was 6 months (58).
      General toxicity to wildlife and fish:
           a.   The 96-hr LC50 of technical bensulide in the common goldfish
                  is 1 to 2 ppm.
           b.   The 96-hr EC50 (loss of equilibrium or death) of bensulide
                  in the brown shrimp (P. azetucus) is in excess of 1 ppm
                  (the highest concentration tested).
           c.   The 96-hr EC50 (shell growth inhibition) of bensulide in the
                  common oyster (C. virginica) is 0.45 ppm.
           d.   The 96-hr LC50 of bensulide in the rainbow trout is 0.72 ppm.
           e.   The 48-hr TL of bensulide in the juvenile estuarine species
                  L. xanthrus) is 0.32 ppm.
           f.   A 21-day dietary feeding study was conducted in the Japanese
                  quail.  A no-effect level was established at 10 ppm (58).
           The chemical information provided below has been condensed
      from original source documents, primarily from "Recognition and
      Management of Pesticide Poisonings", 3rd ed. by Donald P.  Morgan,
      which have been footnoted.  This information has been provided in
      this form for your convenience and general guidance only.  In
      specific cases, further consultation and reference may be required
      and is recommended.  This information is not intended as a sub-
      stitute for a more exhaustive review of the literature nor for the
      judgement of a physician or other trained professional.
           If poisoning is suspected, do not wait for symptoms to develop.
      Contact a physician, the nearest hospital, or the nearest Poison
      Control Center.
      SYMPTOMS OF POISONING:  Expected to be typical of organophosphorous
      poisoning.  No confirmed cases in man (58).
           SKIN CONTACT:  Immediately remove contaminated clothing under a
      safety shower.  Flush all affected areas with large amounts of water
      for at least 15 minutes.  Do not attempt to neutralize with chemical
      agents.  Obtain medical advice immediately (Betasan technical, Betasan
      4-E) (29r,s).  Immediately flush all affected areas with water for at
      least 15 minutes while removing any contaminated clothing.  Seek
      medical attention if irritation occurs (Betasan 3.6-G) (29t).
           INGESTION:  If swallowed -- immediately dilute the swallowed
      material by rapidly giving large quantities of water or milk, if
      available, and induce vomiting by gagging the victim with a finger or
      blunt object placed on the back of the victim's tongue.  Continue fluid
      administration until vomitus is clear.  Never give anything by mouth to
      an unconscious person.  Call a physician or the nearest Poison Control
      Center immediately (Betasan technical) (29r).
           If swallowed -- immediately dilute the swallowed material by
      giving large quantities of water and induce vomiting by gagging the
      victim with a finger or blunt object placed on the back of the victim's
      tongue.  Continue fluid administration until vomitus is clear.  Never
      give anything by mouth to an unconscious person.  Call a physician or
      the nearest Poison Control Center immediately (Betasan 3.6-G) (29t).
      DO NOT induce vomiting.  This product contains hydrocarbon solvent.
      Immediately give large quantities of water.  If vomiting does occur,
      give fluids again.  Never give anything by mouth to an unconscious
      person.  Call a physician or the nearest Poison Control Center
      immediately (Betasan 4-E) (29s).
           INHALATION:  Remove from contaminated atmosphere.  If breathing
      has ceased, clear the victim's airway and start mouth-to-mouth
      artificial respiration, which may be supplemented by the use of a
      bag-mask respirator, or a manually triggered oxygen supply capable of
      delivering 1 liter/second or more.  If the victim is breathing, oxygen
      may be administered from a demand-type or continuous flow inhalator,
      and preferably with a physician's advice.  Contact a physician
      immediately (Betasan 3.6-G, 4-E) (29t,s).
           EYE CONTACT:  Immediately flush the eyes with large quantities of
      running water for a minimum of 15 minutes.  Hold the eyelids apart
      during the irrigation to ensure flushing of the entire surface of the
      eye and lids with water.  Do not attempt to neutralize with chemical
      agents.  Obtain medical attention as soon as possible.  Oils or
      ointments should not be used.  Continue the irrigation for an
      additional 15 minutes if the physician is not immediately available
      NOTES TO PHYSICIAN:  Exposure to the active ingredient may cause
      cholinesterase inhibition.  Atropine by injection is antidotal.  2-PAM
      is also antidotal when administered early and in conjunction with
      atropine (29t).
                        VI.  FIRE AND EXPLOSION INFORMATION
      GENERAL:  Flash point (TOC) 157 C;  fire point, 171 C (58).
                Betasan technical:  An open cup flash point of 315F (29r).
                Betasan 3.6-G:  This material is considered noncombustible.
                  However, under fire conditions it may decompose to give off
                  toxic materials (29t).
                Betasan 4-E:  This material is considered combustible.  Under
                  fire conditions, it will support cumbustion and may
                  decompose to give off toxic materials (29s).
      FIRE FIGHTING TECHNIQUE:  Vapors may be irritating to the respiratory
      tract and may cause breathing difficulty and pulmonary edema.  Symptoms
      may be delayed several hours or longer depending upon exposure.
           As in any fire, prevent human exposure to fire, smoke, fumes or
      products of combustion.  Evacuate nonessential personnel from the fire
           When there is a potential for exposure to smoke, fumes, products
      of combustion, etc., firefighters should wear full-face, self-contained
      breathing apparatus and impervious clothing such as gloves, hoods,
      suits and rubber boots.
           Use standard firefighting techniques in extinguishing fires
      involving this product -- use water, dry chemicals, foam or carbon
      dioxide.  If drums are NOT leaking, keep cooled with a water spray.
      High pressure water hose may spread product from broken containers
      increasing contamination hazards.  Use of contaminated buildings, area
      and equipment must be prevented until they are properly decontaminated
      (Betasan 3.6-G, 4-E) (29t,s).
                                VII.  COMPATIBILITY
           No incompatibilities with hard water; none known or expected with
      other pesticides.  No corrosiveness with mild iron, steel, tin, or
      brass.  Corrosive to copper (58).
                            VIII.  PROTECTIVE MEASURES
      STORAGE AND HANDLING:  Apparently indefinite storage life under normal
      ambient conditions.  Photosensitivity is indeterminate (58).  All food
      must be kept in a separate area away from the storage/use location.
      Eating, drinking, smoking and carrying of tobacco products must be
      prevented in areas where there is a potential for exposure to this
      material.  Before eating, drinking or smoking, hands and face must be
      thoroughly washed (Betasan 4-E) (29s).
      PROTECTIVE CLOTHING: Skin contact with liquid or its aerosol should be
      minimized through the use of suitable protective clothing, gloves and
      footwear, selected with regard for use condition exposure potential.
      Unprotected skin exposed to vapors, aerosol or mist should be
      thoroughly washed at the end of the work shift.
           Eye contact with liquid or its aerosol should be avoided through
      the use of chemical safety glasses, goggles or a face shield, selected
      with regard for use condition exposure potential (Betasan 4-E) (29s).
      PROTECTIVE EQUIPMENT:  If use conditions generate airborne aerosol,
      liquid or vapor, handle this material only in open (e.g. outdoor) or
      well-ventilated areas.  Where adequate ventilation is not available,
      use NIOSH-approved respirators to reduce exposures.  Respirator
      selection must address the potential for exposure under the use
      conditions (Betasan 4-E) (29s).
                       IX.  PROCEDURES FOR SPILLS AND LEAKS
                                  (800) 424-9300
           Make sure all personnel involved in spill are aware of the hazards
      associated with this material.
           A small spill can be handled routinely considering the physical
      and hazardous properties of the product as well as the location of the
      spill.  Use adequate ventilation and wear an air supplied respirator to
      prevent inhalation contact.  Wear protective clothing to prevent skin
      and eye contact.  Soak up pooled liquid as follows:
      1.   If Betasan is in the liquid state:  spread a suitable absorbent
           such as clay on the liquid.
           If Betasan is in the solid state:  sweep up the powder being
           careful not to create dust.
      2.   Place sweepings in an open drum.
      3.   Generously cover the contaminated area with a common household
           detergent (e.g. TIDE).  Using a stiff brush, work the detergent
           into the spill material (adding sufficient water to the solid
           product) to form a slurry.  Brush the slurry into cracks and
           crevices; and allow to stand for 2 to 3 minutes.  Be careful to
           completely avoid skin or eye contact; do not splatter on one's
           self or bystanders.
      4.   Spread absorbents on the slurried liquid, and shovel the absorbed
           material into an open drum.
      5.   Repeat if necessary.
      6.   Flush area with water, while observing proper environmental
      7.   Seal drum and dispose of contaminated material in an approved
           pesticide dump.
      8.   This product is toxic to fish.  Do not contaminate water by
           cleaning of equipment or disposal of wstes.
      Large spills must be handled according to a predetermined plan.  For
      assistance in developing a plan, contact Stauffer's Agricultural
      Chemical Division, Westport, CT 06880 (29r).
                               X.  LITERATURE CITED
       8b. Thomson, W.T.  1981.  Agricultural chemicals - book 2:
               herbicides.  Revised ed.  Thomson Publications, Fresno, CA.
               274 pp.
      29r. Stauffer Chemical Company, Agricultural Chemical Division.  1978.
               Product safety information:  Betasan Technical.  Westport, CT.
      29s. Stauffer Chemical Company, Agricultural Chemical Division.  1980.
               Product safety information:  Betasan 4-E.  Westport, CT.
      29t. Stauffer Chemical Company, Agricultural Chemical Division.  1980.
               Product safety information:  Betasan 3.6-G.  Westport, CT.
      56.  Farm Chemicals Handbook, 70th ed.  1984.  R. T. Meister, G. L.
               Berg, C. Sine, S. Meister, and J. Poplyk, eds.  Meister
               Publishing Co., Willoughby, OH.
      58.  Weed Science Society of America, Herbicide Handbook Committee.
               1983.  Herbicide handbook of the weed science society of
               America, 5th ed.  Weed Science Society of America, Champaign,
               IL.  515 pp.
      62.  The Pesticide Manual:  A World Compendium, 7th ed.  1983.  C.R.
               Worthing, ed.  The British Crop Protection Council, Croydon,
               England.  695 pp.