METHOMYL

White crystalline solid with slight sulfurous smell. Used as a nematocide, and an insecticide on vegetables, tobacco, cotton, alfalfa, soy beans, and corn. (EPA, 1998)

none

Water soluble.

When heated to decomposition, it emits very toxic fumes of nitrogen oxides and sulfur oxides. Do not subject liquid formulations to temperatures below 32F. (EPA, 1998)

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. (EPA, 1998)

METHOMYL 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.

• Carbamates
• Sulfides, Organic

No information available.

Excerpt from 154 [Substances - Toxic and/or Corrosive (Non-Combustible)]:

IMMEDIATE PRECAUTIONARY MEASURE: Isolate spill or leak area in all directions for at least 50 meters (150 feet) for liquids and at least 25 meters (75 feet) for solids.

SPILL: Increase the immediate precautionary measure distance, in the downwind direction, as necessary.

FIRE: If tank, rail car or tank truck is involved in a fire, ISOLATE for 800 meters (1/2 mile) in all directions; also, consider initial evacuation for 800 meters (1/2 mile) in all directions. (ERG, 2020)

(Non-Specific -- Carbamate Pesticide, Solid) Wear self-contained breathing apparatus.

(Non-Specific -- Carbamate Pesticide, Solid) Use agent suitable for type of surrounding fire. Use water in flooding quantities as a fog. Use alcohol foam, carbon dioxide, or dry chemical. (EPA, 1998)

Caution : Flammable. Avoid sources of extreme heat or ignition including sparks or fire. Methomyl will liberate toxic nitrogen and sulfur oxide fumes when heated to decomposition.

(Non-Specific -- Carbamate Pesticide, Solid) Keep unnecessary people away; isolate hazard areas and deny entry. Stay upwind and keep out of low areas. Do not touch spilled material, or handle broken packages without protective equipment. Do not breathe dust, vapors, or the fumes from burning material. (EPA, 1998)

Excerpt from NIOSH Pocket Guide for Methomyl:

Skin: PREVENT SKIN CONTACT - Wear appropriate personal protective clothing to prevent skin contact.

Eyes: PREVENT EYE CONTACT - Wear appropriate eye protection to prevent eye contact.

Wash skin: WHEN CONTAMINATED - The worker should immediately wash the skin when it becomes contaminated.

Remove: WHEN WET OR CONTAMINATED - Work clothing that becomes wet or significantly contaminated should be removed and replaced.

Change: DAILY - Workers whose clothing may have become contaminated should change into uncontaminated clothing before leaving the work premises.

Provide: QUICK DRENCH - Facilities for quickly drenching the body should be provided within the immediate work area for emergency use where there is a possibility of exposure. [Note: It is intended that these facilities provide a sufficient quantity or flow of water to quickly remove the substance from any body areas likely to be exposed. The actual determination of what constitutes an adequate quick drench facility depends on the specific circumstances. In certain instances, a deluge shower should be readily available, whereas in others, the availability of water from a sink or hose could be considered adequate.] (NIOSH, 2023)

Normalized Breakthrough Times (in Minutes)

Chemical	CAS Number	State	QS	QC	SL	C3	TF	TP	RC	TK	RF
Methomyl (29%)	16752-77-5	Liquid							>480	>480	>480

Special Warning from DuPont: Tychem® and Tyvek® fabrics should not be used around heat, flames, sparks or in potentially flammable or explosive environments. Only...

(DuPont, 2023)

Signs and Symptoms of Acute Methomyl Exposure: Acute exposure to methomyl usually leads to a cholinergic crisis. Signs and symptoms may include increased salivation, lacrimation (tearing), spontaneous defecation, and spontaneous urination. Pinpoint pupils, blurred vision, tremor, muscle twitching, and loss of muscle coordination may occur. Mental confusion, convulsions, and coma may also be noted. Gastrointestinal effects include nausea, vomiting, diarrhea, and abdominal pain. Bradycardia (slow heart rate) occurs frequently. Dyspnea (shortness of breath), pulmonary edema, and respiratory arrest may also occur.

Emergency Life-Support Procedures: Acute exposure to methomyl may require decontamination and life support for the victims. Emergency personnel should wear protective clothing appropriate to the type and degree of contamination. Air-purifying or supplied-air respiratory equipment should also be worn, as necessary. Rescue vehicles should carry supplies such as plastic sheeting and disposable plastic bags to assist in preventing spread of contamination.

Inhalation Exposure:
1. Move victims to fresh air. Emergency personnel should avoid self-exposure to methomyl.
2. Evaluate vital signs including pulse and respiratory rate, and note any trauma. If no pulse is detected, provide CPR. If not breathing, provide artificial respiration. If breathing is labored, administer oxygen or other respiratory support.
3. Obtain authorization and/or further instructions from the local hospital for administration of an antidote or performance of other invasive procedures.
4. Transport to a health care facility.

Dermal/Eye Exposure:
1. Remove victims from exposure. Emergency personnel should avoid self- exposure to methomyl.
2. Evaluate vital signs including pulse and respiratory rate, and note any trauma. If no pulse is detected, provide CPR. If not breathing, provide artificial respiration. If breathing is labored, administer oxygen or other respiratory support.
3. Remove contaminated clothing as soon as possible.
4. If eye exposure has occurred, eyes must be flushed with lukewarm water for at least 15 minutes.
5. Wash exposed skin areas three times with soap and water.
6. Obtain authorization and/or further instructions from the local hospital for administration of an antidote or performance of other invasive procedures.
7. Transport to a health care facility.

Ingestion Exposure:
1. Evaluate vital signs including pulse and respiratory rate, and note any trauma. If no pulse is detected, provide CPR. If not breathing, provide artificial respiration. If breathing is labored, administer oxygen or other respiratory support.
2. Obtain authorization and/or further instructions from the local hospital for administration of an antidote or performance of other invasive procedures.
3. Vomiting may be induced with syrup of Ipecac. If elapsed time since ingestion of methomyl is unknown or suspected to be greater than 30 minutes, do not induce vomiting and proceed to Step
4.Ipecac should not be administered to children under 6 months of age.Warning: Ingestion of methomyl may result in sudden onset of seizures or loss of consciousness. Syrup of Ipecac should be administered only if victims are alert, have an active gag-reflex, and show no signs of impending seizure or coma. If ANY uncertainty exists, proceed to Step
4.The following dosages of Ipecac are recommended: children up to 1 year old, 10 mL (1/3 oz); children 1 to 12 years old, 15 mL (1/2 oz); adults, 30 mL (1 oz). Ambulate (walk) the victims and give large quantities of water. If vomiting has not occurred after 15 minutes, Ipecac may be readministered. Continue to ambulate and give water to the victims. If vomiting has not occurred within 15 minutes after second administration of Ipecac, administer activated charcoal.
4. Activated charcoal may be administered if victims are conscious and alert. Use 15 to 30 g (1/2 to 1 oz) for children, 50 to 100 g (1-3/4 to 3-1/2 oz) for adults, with 125 to 250 mL (1/2 to 1 cup) of water.
5. Promote excretion by administering a saline cathartic or sorbitol to conscious and alert victims. Children require 15 to 30 g (1/2 to 1 oz) of cathartic; 50 to 100 g (1-3/4 to 3-1/2 oz) is recommended for adults.
6. Transport to a health care facility. (EPA, 1998)

• ACETIMIDIC ACID, N-((METHYLCARBAMOYL)OXY)THIO-, METHYL ESTER
• ACETIMIDIC ACID, THIO-N-((METHYLCARBAMOYL)OXY)-, METHYL ESTER
• ACETIMIDOTHIOIC ACID, METHYL-, N-(METHYLCARBAMOYL) ESTER
• DU PONT 1179
• DU PONT INSECTICIDE 1179
• ETHANIMIDOTHIOIC ACID, N-(((METHYLAMINO)CARBONYL)OXY)-, METHYL ESTER
• ETHANIMIDOTHIOIC ACID, N-[[METHYLAMINO)CARBONYL]
• IN 1179
• INSECTICIDE 1,179
• LAN BAIT
• LANNATE
• LANNATE 90SP
• LANNATE L
• LANNATE®
• MESOMILE
• METHOMYL
• METHOMYL SP
• METHYL N-((((METHYLAMINO)CARBONYL) OXY)ETHANIMIDO)THIOATE
• METHYL N-((METHYLAMINO)CARBONYL)OXY)ETHANIMIDOTHIOATE
• METHYL N-((METHYLCARBAMOYL)OXY)THIOACETIMIDATE
• METHYL N-[(METHYLCARBAMOYL)OXY]THIOACETIMIDATE
• METHYL N-[[(METHYLAMINO)CARBONYL] OXY]ETHANIMIDOTHIOATE
• METHYL O-(METHYLCARBAMOYL) THIOLACETOHYDROXAMATE
• METHYL O-(METHYLCARBAMOYL)THIOLACETOHYDROXAMATE
• METHYL O-(METHYLCARBAMYL)THIOLACETOHYDROXAMATE
• 1-(METHYLTHIO) ETHYLIDENEAMINO METHYLCARBAMATE
• 1-(METHYLTHIO)ACETALDEHYDE O-METHYLCARBAMOYLOXIME
• MIE DUO WEI
• N-[(METHYLCARBAMOYL)OXY]THIOACETIMIDIC ACID METHYL ESTER
• N-[[(METHYLAMINO) CARBONYL]OXY]ETHANIMIDOTHIOIC ACID METHYL ESTER
• NUDRIN
• S-METHYL N-(METHYLCARBAMOYLOXY)THIOACETIMIDATE
• S-METHYL N-[(METHYLCARBAMOYL)OXY]THIOACETIMIDATE
• S-METHYL-N-(METHYLCARBAMOYLOXY)THIOACETIMIDATE
• SD 14999
• 3-THIABUTAN-2-ONE, O-(METHYLCARBAMOYL)OXIME
• WL 18236