16752-77-5

Acetamidic acid (methomyl) is carbamate broad-spectrum insecticide. Methomyl is clas- sifi ed as a restricted use pesticide (RUP). It is a crystalline solid with a slight sulfurous odor, very soluble in methanol, acetone, ethanol, and isopropanol. It decomposes with heat and releases hazardous gases/vapors, such as sulfur oxides, methylisocyanate, and HCN. Acetamidic acid (methomyl) is used both as a contact insecticide and as a systemic insecticide. It is used as an acaricide to control ticks, spiders, as fl y bait, for foliar treatment of vegetable, fruit and fi eld crops, cotton, commercial ornamentals, and in and around poultry houses and dairies.

white crystalline solid

ChEBI: A carbamate ester obtained by the formal condensation of methylcarbamic acid with the hydroxy group of 1-(methylsulfanyl)acetaldoxime.

Insecticide.

White crystalline solid with slight sulfurous smell. Used as a nematocide, and an insecticide on vegetables, tobacco, cotton, alfalfa, soy beans, and corn.

METHOMYL(16752-77-5) is a carbamate ester. Carbamates are chemically similar to, but more reactive than amides. Like amides they form polymers such as polyurethane resins. Carbamates are incompatible with strong acids and bases, and especially incompatible with strong reducing agents such as hydrides. Flammable gaseous hydrogen is produced by the combination of active metals or nitrides with carbamates. Strongly oxidizing acids, peroxides, and hydroperoxides are incompatible with carbamates.

Water soluble.

Toxic by ingestion. Acetyl cholinesterase inhibitor, male reproductive damage, and hematologic effects. Questionable carcinogen.

Acetamidic acid (methomyl) is potentially a highly poisonous material in humans. Exposures to acetamidic acid (methomyl) cause adverse health effects. It is highly toxic and causes inhibition of cholinesterase activity. The symptoms of toxicity include, but are not limited to, weakness, lack of appetite, blurred vision, pupillary constriction, cor- neal injury, headache, nausea, abdominal cramps, burning sensation, coughing, wheez- ing, laryngitis, shortness of breath, and vomiting. It may be harmful if absorbed through the skin of the mucous membranes and upper upper respiratory tract and cause chest discomfort, constriction of pupils, sweating, muscle tremors, and decreased pulse. After severe poisoning, occupational workers show symptoms of twitching, giddiness, confu- sion, muscle incoordination, heart irregularities, loss of refl exes, slurred speech, paralysis of the muscles of the respiratory system, and death. The target organs of methomyl toxic- ity include nerves, cardiovascular system, liver, and kidneys.

Methomyl has high oral toxicity, moderate inhalation toxicity and low skin toxicity. The probable oral lethal dose for humans is between 7 drops and 1 teaspoon for a 150 pound adult. Death is due to respiratory arrest.

Methomyl is a broad-spectrum insecticide used as insecticide in many vegetables, field crops; certain fruit crops; and ornamentals.
Incompatibilities: Keep away from strong bases, strong oxidizers. Heat causes decomposition forming toxic and irritating fumes including nitrogen oxides; sulfur oxides; hydrogen cyanide; methylisocyanate

When heated to decomposition, METHOMYL emits very toxic fumes of nitrogen oxides and sulfur oxides. Do not subject liquid formulations to temperatures below 32F.

If this chemical gets into the eyes, remove any contact lenses at once and irrigate immediately for at least 15 minutes, occasionally lifting upper and lower lids. Seek medical attention immediately. If this chemical contacts the skin, remove contaminated clothing and wash immediately with soap and water. Seek medical attention immediately. If this chemical has been inhaled, remove from exposure, begin rescue breathing (using universal precautions, including resuscitation mask) if breathing has stopped and CPR if heart action has stopped. Transfer promptly to a medical facility. When this chemical has been swallowed, get medical attention. Give large quantities of water and induce vomiting. Do not make an unconscious person vomit. Medical observation is recommended for 24 to 48 hours after breathing overexposure, as pulmonary edema may be delayed. As first aid for pulmonary edema, a doctor or authorized paramedic may consider administering a drug or other inhalation therapy.

UN2757 Carbamate pesticides, solid, toxic, Hazard Class: 6.1; Labels: 6.1-Poisonous materials. UN2811 Toxic solids, organic, n.o.s., Hazard Class: 6.1; Labels: 6.1-Poisonous materials, Technical Name Required

Consult with environmental regulatory agencies for guidance on acceptable disposal practices. Generators of waste containing this contaminant (≥100 kg/mo) must conform to EPA regulations governing storage, transportation, treatment, and waste disposal. Alkaline hydrolysis leads to complete degradation to nontoxic products. May be dissolved in water and sprayed into a furnace with effluent gas scrubbing also. In accordance with 40CFR165, follow recommendations for the disposal of pesticides and pesticide containers. Must be disposed properly by following package label directions or by contacting your local or federal environmental control agency, or by contacting your regional EPA office.

Notclassified

Insecticide, Acaricide: Methomyl is a broad-spectrum insecticide that is particularly effective against organophosphorus-resistant pests. It is used as an acaricide to control ticks and spiders. It is used for foliar treatment of vegetable, fruit and field crops, tobacco, cotton, commercial ornamentals, and in and around poultry houses and dairies. It is also used as a fly bait. Methomyl is effective as a “contact insecticide,” because it kills target insects upon direct contact, and also as a “systemic insecticide” because of its capability to cause overall “systemic” poisoning in target insects, after it is absorbed and transported throughout the pests that feed on treated plants. It is capable of being absorbed by plants without being “phytotoxic” or harmful, to the plant. A U.S. EPA restricted Use Pesticide (RUP).

ACINATE®; AGRINATE®; CIMETLE®; DuPont TM 1179®; FRAM FLY KILL®; FLYTEK®; IMPROVED BLUE MALRIN SUGAR BAIT®; IMPROVED GOLDEN MALRIN BAIT®; INSECTICIDE 1179®; KIPSIN®; KUIK®; LANNATE®; LANNOX®; LANOX 90®; LANOX 216®; METHOMEX®; METHOMYL® 20SC; MEMILENE®; METHAVIN®; NU-BAIT II®; NUDRIN®; PILLARMATE®; RENTOKILL®; RENTOKIL FRAM FLY BAIT®; RIDECT®; SD 14999®; SOREX GOLDEN FLY BAIT®; WL 18236®

Biological. From the first-order biotic and abiotic rate constants of methomyl in estuarine water and sediment/water systems, the estimated biodegradation half-lives were 75–165 and 39–134 days, respectively (Walker et al., 1988).
Soil. Harvey and Pease (1973) reported that methomyl dissipated rapidly in fine sand and loamy sand soils. One month following application to a Delaware soil, 1.8% of the applied dosage was recovered and after 1 year, methomyl was not detected. T
Groundwater. According to the U.S. EPA (1986) methomyl has a high potential to leach to groundwater.
Plant. The reported half-lives of methomyl on cotton plants, mint plants and Bermuda grass were 0.4–8.5, 0.8–1.2 and 2.5 days, respectively (Willis and McDowell, 1987).
Chemical/Physical. Emits toxic fumes of nitrogen and sulfur oxides when heated to decomposition (Sax and Lewis, 1987; Lewis, 1990).

Keep away from strong bases, strong oxidizers. Heat causes decomposition forming toxic and irritating fumes including nitrogen oxides, sulfur oxides, hydrogen cyanide, methylisocyanate.