Bensulid (ISO)

Fresh air, rest. Refer for medical attention.

Remove contaminated clothes. Rinse and then wash skin with water and soap.

First rinse with plenty of water for several minutes (remove contact lenses if easily possible), then refer for medical attention.

Rest. Refer for medical attention .

Biological Exposure Indices (BEI) [ACGIH] - Acetylcholinesterase activity in red blood cells = 70% of individual's baseline; Butylcholinesterase activity in serum or plasma = 60% of individual's baseline; Sample at end of shift; [TLVs and BEIs]

SRP: Recycle any unused portion of the material for its approved use or return it to the manufacturer or supplier. Ultimate disposal of the chemical must consider: the material's impact on air quality; potential migration in air, soil or water; effects on animal, aquatic and plant life; and conformance with environmental and public health regulations. If it is possible or reasonable use an alternative chemical product with less inherent propensity for occupational harm/injury/toxicity or environmental contamination.

Personal protection: particulate filter respirator adapted to the airborne concentration of the substance. Do NOT wash away into sewer. Sweep spilled substance into covered sealable containers. If appropriate, moisten first to prevent dusting. Carefully collect remainder. Then store and dispose of according to local regulations.

Avoid contact with eyes and skin and inhalation of spray mists. Guard against drift.

SRP: The scientific literature for the use of contact lenses by industrial workers is inconsistent. The benefits or detrimental effects of wearing contact lenses depend not only upon the substance, but also on factors including the form of the substance, characteristics and duration of the exposure, the uses of other eye protection equipment, and the hygiene of the lenses. However, there may be individual substances whose irritating or corrosive properties are such that the wearing of contact lenses would be harmful to the eye. In those specific cases, contact lenses should not be worn. In any event, the usual eye protection equipment should be worn even when contact lenses are in place.

If the compound has been ingested, rapid gastric lavage should be performed using 5% sodium bicarbonate. For skin contact, the skin should be washed with soap and water. If the compound has entered the eyes, they should be washed with large quantities of isotonic saline or water. In serious cases, atropine and/or pralidoxime should be administered. Anti-cholinergic drugs work to counteract the effects of excess acetylcholine and reactivate AChE. Atropine can be used as an antidote in conjunction with pralidoxime or other pyridinium oximes (such as trimedoxime or obidoxime), though the use of '-oximes' has been found to be of no benefit, or possibly harmful, in at least two meta-analyses. Atropine is a muscarinic antagonist, and thus blocks the action of acetylcholine peripherally.

Acute exposure to cholinesterase inhibitors can cause a cholinergic crisis characterized by severe nausea/vomiting, salivation, sweating, bradycardia, hypotension, collapse, and convulsions. Increasing muscle weakness is a possibility and may result in death if respiratory muscles are involved. Accumulation of ACh at motor nerves causes overstimulation of nicotinic expression at the neuromuscular junction. When this occurs symptoms such as muscle weakness, fatigue, muscle cramps, fasciculation, and paralysis can be seen. When there is an accumulation of ACh at autonomic ganglia this causes overstimulation of nicotinic expression in the sympathetic system. Symptoms associated with this are hypertension, and hypoglycemia. Overstimulation of nicotinic acetylcholine receptors in the central nervous system, due to accumulation of ACh, results in anxiety, headache, convulsions, ataxia, depression of respiration and circulation, tremor, general weakness, and potentially coma. When there is expression of muscarinic overstimulation due to excess acetylcholine at muscarinic acetylcholine receptors symptoms of visual disturbances, tightness in chest, wheezing due to bronchoconstriction, increased bronchial secretions, increased salivation, lacrimation, sweating, peristalsis, and urination can occur. Certain reproductive effects in fertility, growth, and development for males and females have been linked specifically to organophosphate pesticide exposure. Most of the research on reproductive effects has been conducted on farmers working with pesticides and insecticdes in rural areas. In females menstrual cycle disturbances, longer pregnancies, spontaneous abortions, stillbirths, and some developmental effects in offspring have been linked to organophosphate pesticide exposure. Prenatal exposure has been linked to impaired fetal growth and development. Neurotoxic effects have also been linked to poisoning with OP pesticides causing four neurotoxic effects in humans: cholinergic syndrome, intermediate syndrome, organophosphate-induced delayed polyneuropathy (OPIDP), and chronic organophosphate-induced neuropsychiatric disorder (COPIND). These syndromes result after acute and chronic exposure to OP pesticides.

LC50; Species: Gammarus fasciatus /freshwater shrimp/, mature; Conditions: static bioassay without aeration, 15 °C, pH 7.2-7.5, water hardness 40-50 mg/L as calcium carbonate and alkalinity of 30-35 mg/L; Concentration: 1.4 mg/L for 96 hr (95% confidence limit: 0.4-5.1 mg/L)

LC50; Species: Penaeus azetucus (brown shrimp), loss of equilibrium or death; Concentration: > 1 ppm for 96 hr/Conditions of bioassay not specified/

LC50; Species: /Carassius auratus/ (Common goldfish); Concentration: 1-2 ppm for 96 hr /Conditions of bioassay not specified/

LD50; Species: Apis mellifera (Honey Bee) worker; topical, general 24 ug/bee

For more Ecotoxicity Values (Complete) data for Bensulide (24 total), please visit the HSDB record page.

TERRESTRIAL FATE: Based on a classification scheme(1), a Koc value of 1,000(2) indicates that bensulide is expected to have low mobility in soil(SRC). Volatilization of bensulide from moist soil surfaces is not expected to be an important fate process(SRC) given an estimated Henry's Law constant of 1.7X10-8 atm-cu m/mole(SRC), derived from its vapor pressure, 8.0X10-7 mm Hg(3), and water solubility, 25 mg/L(4). Bensulide is not expected to volatilize from dry soil surfaces(SRC) based upon its vapor pressure(3). Bensulide is considered persistent in soils due to its very slow degradation, achieving 75-100% reduction of applied amounts after 5 months(5); therefore, biodegradation is a slow environmental fate process in soil(SRC).

FIELD STUDY: In a field study of agricultural soils, the half-life values of bensulide were 44.3, 37.6, and 27.1 days in sewage sludge-yard waste, sewage sludge, and unamended soils, respectively. With the addition of sewage sludge-yard waste and sewage sludge to the native soil increases in water infiltration were observed, lowering run-off water volume and bensulide residues in run-off following natural rainfall events(1).

AQUATIC FATE: Based on a classification scheme(1), a Koc value of 1000(2), indicates that bensulide may adsorb to suspended solids and sediment(SRC). Volatilization from water surfaces is not expected(3) based upon an estimated Henry's Law constant of 1.7X10-8 atm-cu m/mole(SRC), derived from its vapor pressure, 8.0X10-7 mm Hg(4), and water solubility, 25 mg/L(5). According to a classification scheme(6), a BCF of 880(7), suggests the potential for bioconcentration in aquatic organisms is high(SRC). Bensulide's persistence in soil(8) would suggest that biodegradation may be a slow aquatic environmental fate process(SRC). Bensulide has a reported hydrolysis half-life of 9.9 days(9).

ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), bensulide, which has a vapor pressure of 8.0X10-7 mm Hg at 25 °C(2), will exist in both the vapor and particulate phases in the ambient atmosphere. Vapor-phase bensulide is degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals(SRC); the half-life for this reaction in air is estimated to be 2.3 hours(SRC), calculated from its rate constant of 1.7X10-10 cu cm/molecule-sec at 25 °C(SRC) that was derived using a structure estimation method(3). Particulate-phase bensulide may be removed from the air by wet and dry deposition(SRC). It is reported that bensulide decomposes slowly in light(5).

Bensulide was tested for but not detected, limit of quantitation = 0.1 ppm, in domestic and imported pears and tomatoes(1). A total of 129,524 lbs active ingredient bensulide/yr were applied to 29% of the watermelon crop in the US during 1987/89(2). Bensulide residues have not been detected in dietary field trials(3).

In FDA total diet studies analyzing foods for human consumption as part of the pesticide monitoring program during the fiscal year 2013, bensulide was not listed for inclusion in the study; during the fiscal years 2009 through 2012 bensulide was listed as a pesticide in the monitoring program although it was not detected in the foods studied(1).

IDENTIFICATION AND USE: Bensulide is a viscous amber liquid above 34.4 °C, and a solid below that temperature. It is used for pre-emergence control of annual grasses and broad-leaved weeds in established turf, dichondra, brassicas, cucurbits, watermelons, cotton, lettuce, tomatoes, carrots, capsicums, rice, and herbage seed crops. HUMAN STUDIES: No data. ANIMAL STUDIES: Bensulide is a cholinesterase inhibitor and mild irritant in rabbit eyes. Rats tolerated 1 hr exposures to 8 mg/L air. In 90 day feeding trials, no-effect level for rats was 25 mg/kg/day, for dogs 2.5 mg/kg/day, and for mice 30 mg/kg/day. In a chronic toxicity study in dogs, bensulide (92.4% a.i.) was administered to 4 dogs/sex/dose by feeding at dose levels of 0, 0.5, 4, or 30 mg/kg/day for 52 weeks. No neoplastic tissue was observed in dogs in the treatment and control groups. Chronic toxicity in rats receiving 60 mg/kg/day was characterized in both sexes by reduced cholinesterase levels in plasma, erythrocytes, and brain, and, in the males, by increased absolute liver weights and mild histopathological changes of the liver (hepatocyte vacuolation and eosinophilic foci). In the 15 mg/kg/day animals, reduced plasma and erythrocyte cholinesterase activities were also observed. In developmental toxicity studies bensulide exerted no effects on maternal gross pathology, fertility, or cesarian parameters and the lack of any developmental effects. Bensulide was not mutagenic when evaluated for its ability to induce point mutations in the T4 bacteriophage/Escherichia coli B system. ECOTOXICITY STUDIES: Bensulide was toxic to fish and inhibited germination in grasses.

Bensulide is a cholinesterase or acetylcholinesterase (AChE) inhibitor. A cholinesterase inhibitor (or 'anticholinesterase') suppresses the action of acetylcholinesterase. Because of its essential function, chemicals that interfere with the action of acetylcholinesterase are potent neurotoxins, causing excessive salivation and eye-watering in low doses, followed by muscle spasms and ultimately death. Nerve gases and many substances used in insecticides have been shown to act by binding a serine in the active site of acetylcholine esterase, inhibiting the enzyme completely. Acetylcholine esterase breaks down the neurotransmitter acetylcholine, which is released at nerve and muscle junctions, in order to allow the muscle or organ to relax. The result of acetylcholine esterase inhibition is that acetylcholine builds up and continues to act so that any nerve impulses are continually transmitted and muscle contractions do not stop. Among the most common acetylcholinesterase inhibitors are phosphorus-based compounds, which are designed to bind to the active site of the enzyme. The structural requirements are a phosphorus atom bearing two lipophilic groups, a leaving group (such as a halide or thiocyanate), and a terminal oxygen.

/AQUATIC SPECIES/ A scan of the acute toxicities of eighteen common herbicides to one-year-old channel catfish (Ictalurus punctatus) was conducted. Herbicides causing less than 10% mortality in 48 hr at 10 ppm were: alanap, chloramben, 2,4-D acid, 2,4-D dimethyl amine salt, dalapon, diuron, DSMA, EPTC, fluometuron, metribuzin, monuron, MSMA, nitralin and 2,4,5,-T. The 96-hr LC50 values in pp6 for four nerbicides found toxic were: propanil, 3796; trifluralin, 417; bensulide, 379; and DNBP 118. The toxicity of Dyanap, a mixture of DNBP and alanap, was lower than that of DNBP; there was no apparent synergism between DNBP and alanap in the mixture.

/PLANTS/ Oat seedlings were grown by two different methods in various concentrations of bensulide. Root growth was inhibited, the roots were sometimes curved and root hairs were often present close to the root tip. Structural features of the treated roots included epidermal cells which were greatly elongated radially; short, pitied trachcary elements differentiated close to the root tip; and occasional lesions. One of the primary effects of bensulide appears to be inhibition of root growth, though it does not completely inhibit mitosis.

/PLANTS/ Inhibits germination in grasses.

/PLANTS/ It inhibits the growth of roots of weeds.

/PLANTS/... Pepper, watermelon, cotton, lettuce, tomato and carrot were tolerant to concn of <1,000 ppm bensulide in fine sandy loam soil. Cabbage and onion were tolerant to bensulide levels of 725 ppm or less.

Pupillary constriction. Excessive salivation. Lacrimation. Urination. Diarrhoea. Shortness of breath. Muscle cramps. Unconsciousness.

MAY BE ABSORBED! Itching. Rash. Redness. Pain. Further see Inhalation.

Redness. Pain. Further see Inhalation.

Abdominal cramps. Confusion. Vomiting. Weakness. Further see Inhalation.

Symptoms of low dose exposure include excessive salivation and eye-watering. Acute dose symptoms include severe nausea/vomiting, salivation, sweating, bradycardia, hypotension, collapse, and convulsions. Increasing muscle weakness is a possibility and may result in death if respiratory muscles are involved. Hypertension, hypoglycemia, anxiety, headache, tremor and ataxia may also result.

EPA has released the Interactive Chemical Safety for Sustainability (iCSS) Dashboard. The iCSS Dashboard provides an interactive tool to explore rapid, automated (or in vitro high-throughput) chemical screening data generated by the Toxicity Forecaster (ToxCast) project and the federal Toxicity Testing in the 21st century (Tox21) collaboration. /The title compound was tested by ToxCast and/or Tox21 assays/[USEPA; ICSS Dashboard Application; Available from, as of December 8, 2016: http://actor.epa.gov/dashboard/]

Tolerances are established for the residues of S-(O,O-diisopropyl phosphorodithioate) of N-(2-mercaptoethyl) benzenesulfonamide including its oxygen analog S-(O,O-diisopropyl phosphorothioate) of N-(2-mercaptoethyl) benzenesulfonamide in or on the following food commodities:[Table#1186]

Tolerances with regional registration, as defined in section 180.1(l), are established for the residues of S-(O,O-diisopropyl phosphorodithioate) of N-(2-mercaptoethyl) benzenesulfonamide including its oxygen analog S-(O,O-diisopropyl phosphorothioate) of N-(2-mercaptoethyl) benzenesulfonamide in or on the following food commodities: carrot, roots.[Table#1187]

EPA has concluded, after completing its assessment of the cumulative risks associated with exposures to all of the OPs /including bensulide/, that: (1) the pesticides covered by the IREDs that were pending the results of the OP cumulative assessment (listed in Attachment A) are indeed eligible for reregistration; and (2) the pesticide tolerances covered by the IREDs and TREDs that were pending the results of the OP cumulative assessment (listed in Attachment A) meet the safety standard under Section 408(b)(2) of the FFDCA. Thus, with regard to the OPs, EPA has fulfilled its obligations as to FFDCA tolerance reassessment and FIFRA reregistration, other than product-specific reregistration.

The Agency has completed its assessment of the occupational and ecological risks associated with the use of pesticides containing the active ingredient bensulide, as well as a bensulide-specific dietary risk assessment that has not considered the cumulative effects of organophosphates as a class. Based on a review of these data and public comments on the Agency's assessments for the active ingredient bensulide, EPA has sufficient information on the human health and ecological effects of bensulide to make an interim determination of reregistration eligibility and to make some interim decisions as part of the tolerance reassessment process under FQPA. Although the Agency has not yet completed its cumulative risk assessment for the organophosphates, the Agency is issuing this interim assessment now in order to identify risk reduction measures that are necessary to allow the continued use of bensulide. ... As a result of its assessment of the remaining risks of bensulide alone, EPA has determined that certain uses of bensulide, unless amended as set forth in this document, present risks inconsistent with FIFRA. Accordingly, EPA may commence a full risk/benefit analysis, the outcome of which may indicate that cancellation proceedings are warranted, unless registrants agree to label changes implementing the risk reduction measures discussed in this reregistration eligibility decision. At the time that a cumulative assessment is conducted, the Agency will address any outstanding risk concerns. For bensulide, if all changes outlined in this document are incorporated into the labels, then all risks will be mitigated and no outstanding risk concerns for this individual chemical will remain. But, because this is an Interim RED, the Agency may take further actions, if warranted, to finalize the reregistration eligibility decision for bensulide after assessing the cumulative risk of the organophosphate class. ... Because the Agency has not yet completed the cumulative risk assessment for the organophosphates, this reregistration eligibility decision does not fully satisfy the reassessment of the existing bensulide food residue tolerances as called for by the Food Quality Protection Act (FQPA). When the Agency has completed the cumulative assessment, bensulide tolerances will be reassessed in that light. At that time, the Agency will reassess bensulide along with the other organophosphate pesticides to complete the FQPA requirements and make a final reregistration determination.

As the federal pesticide law FIFRA directs, EPA is conducting a comprehensive review of older pesticides to consider their health and environmental effects and make decisions about their continued use. Under this pesticide reregistration program, EPA examines newer health and safety data for pesticide active ingredients initially registered before November 1, 1984, and determines whether the use of the pesticide does not pose unreasonable risk in accordance to newer safety standards, such as those described in the Food Quality Protection Act of 1996. Pesticides for which EPA had not issued Registration Standards prior to the effective date of FIFRA '88 were divided into three lists based upon their potential for human exposure and other factors, with List B containing pesticides of greater concern than those on List C, and with List C containing pesticides of greater concern than those on List D. Bensulide is found on List B. Case No: 2035; Pesticide type: Herbicide; Case Status: OPP is reviewing data from the pesticide's producers regarding its human health and/or environmental effects, or OPP is determining the pesticide's eligibility for reregistration and developing the Reregistration Eligibility Decision (RED) document.; Active ingredient (AI): Bensulide; Data Call-in (DCI) Date(s): 06/11/91, 03/03/95, 10/13/95; AI Status: The producers of the pesticide has made commitments to conduct the studies and pay the fees required for reregistration, and are meeting those commitments in a timely manner.

Used as a pre-emergence herbicide for control of annual grasses and broad-leaved weeds in lawns, turf, watermelons, cotton, rice, vegetables, rice, and other crops; [HSDB]

Farming (Pesticides) [Category: Industry]

For bensulide (USEPA/OPP Pesticide Code: 009801) ACTIVE products with label matches. /SRP: Registered for use in the U.S. but approved pesticide uses may change periodically and so federal, state and local authorities must be consulted for currently approved uses./

For the control of undesirable grasses in lawns and broadleaf weeds.

A selective compound applied preemergence. It must be applied to soil before weeds emerge. Batasan for dichondra and grass lawns including seasonal control of crabgrass and annual bluegrass. Prefar for carrots, cole crops, cucurbits, vegetables (leafy, dry bulb, fruiting).

Betasan is registered for control of... redroot, pigweed, watergrass, lambsquarters, shepherdspurse, goosegrass, and deadnettle in grass and dichondra lawns.

... A mixture of 13.2 grams (0.06 mol) of N-(beta-chloroethyl)-benzene sulfonamide, 25.2 grams (0.1 mol) of potassium-diisopropyl dithiophosphate and 100 ml of methyl ethyl ketone yielded after 4 hour reflux period, 20.8 grams (88% theory) of viscous product.

Bensulide is produced by reaction of O,O-diisopropylphosphorodithioate with N-chloroethylbenzene sulfonamide.

Betamec 4 Pre-Emergence Grass Killer (PBI/Gordon Corp): Active ingredient: Bensulide 46.0%.

Pre-San 7G (PBI/Gordon Corp): Active ingredient: Bensulide 7.0%.

Betasan 3.6 (PBI/Gordon Corp): Active ingredient: Bensulide 3.6%.

Anderson's Weedgrass Preventer (The Anderson's Inc): Active ingredient: Bensulide 8.5%.

For more Formulations/Preparations (Complete) data for Bensulide (14 total), please visit the HSDB record page.

The WHO Recommended Classification of Pesticides by Hazard identifies Bensulide (technical grade) as Class II: moderately hazardous; Main Use: herbicide.

Crabgrass control was decreased with ground straw and mimosa soil additions. Acid soil and increased soil cation capacity also decreased effectiveness of Bensulide.

Betasan should be used prior to germination of weed seeds... Applied to established grass lawns prior to planting, at time of planting, or on established dichondra lawns. ...Must be watered into soil after application. ...Care should be exercised if reseeding with grass is planned following treatment. Prefar should be applied by preplant incorporation 1-2 in deep, or preemergence followed by sprinkler or furrow irrigation. Rates of application are from 10-20 lb/acre for Betasan and 2-6 lb/acre for Prefar. Water at rate of 15-30 gal/3,000-3,600 sq ft is usual carrier for emulsifiable liquid formulations of Betasan. Prefar is applied in 20-50 gal/acre of water.

A preliminary test is required if mixed with wettable powder suspensions.

Compatible with other pesticides.