Methidathion is used in the control of scale insects, leaf eaters, and some mites.
Registry Numbers and Inventories.
EC Index Number
Very toxic; Harmful; Dangerous for the Environment
Agricultural Chemical and Pesticide; Mutagen; Human Data; Primary Irritant
Swiss Giftliste 1
Melting point, °C
Vapor pressure, mmHg
1.495 g/cm3 (20 C)
Solubility in water
at 20 C: 250 mg/L
Partition coefficient, pKow
Hazards and Protection.
Store at in dry place above 32 degrees F to prolong shelf-life.
All chemicals should be considered hazardous. Avoid direct physical contact. Use appropriate, approved safety equipment. Untrained individuals should not handle this chemical or its container. Handling should occur in a chemical fume hood.
Wear appropriate protective gloves, clothing and goggles.
Wear positive pressure self-contained breathing apparatus (SCBA).
(Non-Specific -- Organophosphorus Pesticide, n.o.s.) Stay upwind; keep out of low areas. Ventilate closed spaces before entering them. Do not touch spilled material; stop leak if you can do so without risk. Use water spray to reduce vapors. Small spills: absorb with sand or other noncombustible absorbent material and place into containers for later disposal. Small dry spills: with clean shovel place material into clean, dry containers and cover; move containers from spill area. Large spills: dike far ahead of spill for later disposal.
(Non-Specific -- Organophosphorus Pesticide, n.o.s.) Stay upwind; keep out of low areas. Move container from fire area if you can do so without risk. Fight fire from maximum distance. Dike fire control water for later disposal; do not scatter the material. Wear positive pressure breathing apparatus and special protective clothing.(Non-Specific -- Organophosphorus Pesticide, n.o.s.) This material may burn, but does not ignite readily. For small fires, use dry chemical, carbon dioxide, water spray, or foam. For large fires, use water spray, fog, or foam.
HIGHLY FLAMMABLE: Will be easily ignited by heat, sparks or flames.
Container may explode in heat of fire. Fire and runoff from fire control water may produce irritating or poisonous gases. Stable in neutral or weak acid solution. Hydrolyzed by alkali.
Fire will produce irritating, corrosive and/or toxic gases.
Fever, low heart rate and abnormally low blood pressure, or rapid heart rate and elevated blood pressure may occur. Headache, dizziness, muscle spasms and profound weakness are common. Alterations of level of consciousness, anxiety, paralysis, seizures and coma may occur. Seizures may be more common in children.
Vomiting, hypersalivation, diarrhea, fecal incontinence and abdominal pain may occur.
Dyspnea, rales, bronchorrhea, bronchospasm, or tachypnea may be noted. Noncardiogenic pulmonary edema may occur in severe cases. Chemical pneumonitis may be seen.
Sweating is a consistent but not universal sign.
Constriction of the pupil, tearing, and blurred vision are common. Prolonged dialation of the pupils may occur in severe poisonings. Opsoclonus has been reported in one case. Salivation commonly occurs.
Seek medical assistance.
Move victim to fresh air. Apply artificial respiration if victim is not breathing. Do not use mouth-to-mouth method if victim ingested or inhaled the substance; induce artificial respiration with the aid of a pocket mask equipped with a one-way valve or other proper respiratory medical device. Administer oxygen if breathing is difficult. Remove and isolate contaminated clothing and shoes.
Remove and isolate contaminated clothing and shoes. In case of contact with substance, immediately flush with running water for at least 20 minutes. Wash skin with soap and water.
In case of contact with substance, immediately flush with running water for at least 20 minutes.
USCG CHRIS Code