© 2026 Sinochem Nanjing Corporation,
All Right Reserved
Chemical Name: O,O-Dimethyl-O-(4-Nitrophenyl) Phosphorothioate
Common Names: Methyl parathion
Appearance: Pale yellow liquid or crystalline solid, with a faint odor reminiscent of some solvents found in agricultural shops.
Use: Primarily used as an organophosphate insecticide on certain crops.
Odor Threshold: Not easily noticeable until concentrated. I remember walking past treated fields and detecting a slightly sharp odor, especially where spraying was heavy.
Physical Hazards: Highly toxic by inhalation, ingestion, and skin contact.
Health Hazards: Causes nervous system damage by interrupting acetylcholinesterase activity; symptoms start with headaches or dizziness and, at higher doses, seizures and respiratory paralysis.
Environmental Hazards: Extremely hazardous to aquatic life and bee populations—fields sprayed with it usually experience sudden drops in local insect activity, which the reports confirm.
Signal Word: Danger, reflecting high toxicity.
GHS Classification: Acute Toxin (oral, dermal, inhalation), Environmental Hazard (acute and long-term).
Label Elements: Skulls on containers are not exaggerated—physical contact, even at low levels, leads to adverse health effects.
Potential Routes of Exposure: Absorption through skin, accidental ingestion by improper handling, or inhalation of droplets and dust.
Main Ingredient: O,O-Dimethyl-O-(4-Nitrophenyl) Phosphorothioate, typically between 90–100% purity in formulations.
Impurities: Trace amounts of related phosphorothioates, possible solvents or stabilizers depending on manufacturing process.
Structural Formula: Features nitro and phosphorothioate groups—telltale for potent insecticides.
Type: Organophosphate ester, among the more potent in its class.
Inhalation: Move the affected person to fresh air immediately, support their breathing. Do not ignore mild symptoms like sweating or muscle twitching—seek medical help quickly, as organophosphates act fast.
Skin Contact: Remove contaminated clothing, wash skin thoroughly with soap and water—this is non-negotiable, as even a drop can lead to systemic poisoning.
Eye Exposure: Flush with plenty of clean water, eyelids held apart, for at least fifteen minutes.
Ingestion: Do not induce vomiting; rinse mouth thoroughly and get to a doctor as fast as possible.
Antidote: Atropine sulfate and pralidoxime are standard, but only a trained professional should administer them.
Suitable Extinguishers: Use dry chemical, foam, or CO2. Standard water jets may spread chemical runoff further.
Special Hazards: Burning may generate toxic fumes: phosphorus oxides, sulfur oxides, and nitrogen oxides. Firefighters I’ve spoken to always use breathing apparatus in these cases.
Protective Equipment: Full-body chemical protective clothing is the minimum during a fire—the compounds formed in combustion complicate cleanup.
Firefighting Precaution: Control runoff to prevent environmental contamination; water used must be contained and disposed of safely.
Personal Precautions: Evacuate non-essential personnel, gear up in chemical-resistant suits, gloves, and boots. Only trained personnel should clean up these spills, no matter how minor.
Environmental Precautions: Avoid release into sewers, soil, or waterways—organophosphates move through soil and poison water easily.
Containment: Use absorbent, non-combustible materials like sand or earth to block flow.
Cleanup Methods: Collect residue in leak-proof containers, label, and send for hazardous waste disposal.
Decontamination: Surfaces get washed with alkaline detergent or dilute bleach—simply water alone does not deactivate the chemical.
Safe Handling: Only mix in a well-ventilated setting or with engineered ventilation, and always wear protection. Training in safe chemical handling matters; do not cut corners.
Storage Conditions: Keep container sealed, in a cool, dry place away from sunlight and incompatible chemicals.
Incompatibilities: Avoid mixing with strong oxidizing agents, acids, or alkalis—breakdown leads to violent reactions or more toxic byproducts.
Special Precautions: Storage room should be locked, clearly labeled, and only accessible to authorized staff.
Exposure Limits: National occupational exposure limits for organophosphates are strict; keep airborne levels as low as possible.
Engineering Controls: Use local exhaust ventilation, closed filling systems, or glove boxes during manipulation.
Personal Protection: Chemical-resistant gloves (such as nitrile), impervious clothing, boots, and safety goggles or face shield make a real difference.
Respiratory Protection: Use a NIOSH-approved respirator if ventilation is not up to the task.
Hygiene: Wash hands thoroughly after handling, before eating or smoking. Do not eat in workspaces. Wash work clothing separately.
Physical State: Clear to pale yellow liquid or crystalline solid at room temperature.
Melting Point: Falls between 35–37°C.
Boiling Point: Around 375°C; not easy to evaporate at ambient temperatures.
Solubility: Low in water, highly soluble in most organic solvents.
Odor: Faint aromatic or solvent-like character.
Vapor Pressure: Low; inhalation risk climbs in poorly ventilated spaces or if heated.
Density: Slightly denser than water.
Chemical Stability: Stable under normal storage and use.
Incompatible Materials: Strong acids, bases, and oxidizers provoke breakdown, releasing hazardous byproducts.
Hazardous Decomposition: Heating or burning creates phosphorus and sulfur oxides, nitrous gases—highly toxic.
Reactivity: Hydrolyzes slowly in water; much quicker with alkali, forming less toxic metabolites.
Acute Toxicity: Extremely toxic by all exposure routes, with LD50 values for oral, dermal, and inhalation routes well below many common pesticides.
Chronic Effects: Prolonged exposure triggers neurological symptoms: memory loss, muscle weakness, sometimes lasting long after exposure ends.
Symptoms: Nausea, vomiting, tightness in chest, muscle twitching, pinpoint pupils—these do not wait to show up.
Carcinogenicity: Current studies do not classify as proven human carcinogen, but concerns exist for chronic low-level exposure based on animal research.
Sensitization: Skin reactions, allergic asthma sometimes reported in workers, though less commonly than other organophosphates.
Ecotoxicity: Deadly to freshwater and marine life; concentrations found in run-off can decimate local aquatic populations.
Persistence: Does not linger in soil for more than a few weeks in warm, moist conditions but highly mobile while present.
Bioaccumulation: Tends not to build up in animal tissue for long, breaking down into less toxic forms.
Impact on Pollinators: Lethal to bees and beneficial insects—whole hives can collapse within days after nearby spraying.
Disposal Method: Never dump into drains, bodies of water, or regular trash. Double-bag in sturdy chemical-waste containers for hazardous waste incineration.
Container Disposal: Rinse containers three times with a solvent like water or dilute bleach, then send to a hazardous-waste site. Field workers sometimes mishandle empties, leading to localized poisonings—training on this point is sorely needed.
Waste Streams: All washings, spent containers, and contaminated personal protection should go through hazardous waste channels.
UN Classification: Classified as a toxic substance for transportation.
Shipping Name: Organophosphate Pesticide, Liquid, Toxic.
Packing Group: Highest hazard group under current shipping guidelines.
Precautions: No mixed loads with food, feed, or household goods in transport—one spill could spark a community health crisis.
Spill Response: Local authorities enforce strict spill reporting and response plans, especially near agricultural areas.
Legal Status: Use and handling fall under strict regulation in most countries, with varying bans or phased-out statuses depending on local pesticide laws.
Workplace Controls: Occupational health standards demand monitoring and recordkeeping, particularly in agricultural applications.
Environmental Restrictions: Most regulatory bodies prohibit its use near watercourses or in wildlife refuges, thanks to high ecological risk.
Public Health Policies: Some countries ban household use. Most require clear labeling and public notification for field spraying.
