Paraquat dichloride

1.24 to 1.26 at 68 °F (NTP, 1992)

1.24 g/cm³

1.24

1.24

greater than or equal to 100 mg/mL at 66 °F (NTP, 1992)

Solubility in water, g/100ml at 20 °C: 62

Miscible

Decomposes (NIOSH, 2024)

decomposes

Decomposes

Decomposes 572 °F (EPA, 1998)

572 °F (decomposes)

572 °F (Decomposes)

Approximately 0 (EPA, 1998)

0.0000001 [mmHg]

Vapor pressure, Pa at 25 °C:

<0.0000001 mmHg

<0.0000001 mmHg

Paraquat dichloride is a colorless to yellow crystalline solid. Used as a contact herbicide and desiccant. (EPA, 1998)

Yellow solid with a faint, ammonia-like odor. [herbicide] [Note: Paraquat may also be found commercially as a methyl sulfate salt C12H14N2+2CH3SO4.]; [NIOSH]

COLOURLESS HYGROSCOPIC CRYSTALS.

[herbicide] [Note: Paraquat may also be found commercially as a methyl sulfate

Yellow solid with a faint, ammonia-like odor. [herbicide] [Note: Paraquat may also be found commercially as a methyl sulfate salt C12H14N2 • 2CH3SO4.]

Danger

H301: Toxic if swallowed [Danger Acute toxicity, oral]；H311: Toxic in contact with skin [Danger Acute toxicity, dermal]；H315: Causes skin irritation [Warning Skin corrosion/irritation]；H319: Causes serious eye irritation [Warning Serious eye damage/eye irritation]；H330: Fatal if inhaled [Danger Acute toxicity, inhalation]；H335: May cause respiratory irritation [Warning Specific target organ toxicity, single exposure; Respiratory tract irritation]；H372 **: Causes damage to organs through prolonged or repeated exposure [Danger Specific target organ toxicity, repeated exposure]；H400: Very toxic to aquatic life [Warning Hazardous to the aquatic environment, acute hazard]；H410: Very toxic to aquatic life with long lasting effects [Warning Hazardous to the aquatic environment, long-term hazard]

P260, P261, P262, P264, P264+P265, P270, P271, P273, P280, P284, P301+P316, P302+P352, P304+P340, P305+P351+P338, P316, P319, P320, P321, P330, P332+P317, P337+P317, P361+P364, P362+P364, P391, P403+P233, P405, and P501 (click each P-code to see the statement)

Danger

Hazard Traits - Hazard Trait Undefined；Authoritative List - CECBP - Priority Chemicals；Report - if used as a fragrance or flavor ingredient

Paraquat dichloride is listed in the dataset of EPA Human Health Benchmarks for Pesticides under the Safe Drinking Water Act (40 eCFR 141)

Status: Active Update: 26-01-2023 https://echa.europa.eu/registration-dossier/-/registered-dossier/29834

Paraquat dichloride: Does not have an individual approval but may be used as a component in a product covered by a group standard. It is not approved for use as a chemical in its own right.

The New Jersey Worker and Community Right to Know Act requires public and private employers to provide information about hazardous substances at their workplaces. (N.J.S.A. 34:5A-1 et. seq.)

Avoid strong oxidizers. (EPA, 1998)

Not combustible. Gives off irritating or toxic fumes (or gases) in a fire.

Contact injuries in workers include skin rashes, burns, eye damage from splashes, nail damage, and nasal bleeding. Parquat absorption through the skin can contribute to systemic toxicity, especially when contacting damaged skin or sensitive areas like the buttocks and genitalia. Toxic ingestion: low doses (<20 mg/kg) cause local irritation to oral and GI mucosa; moderate doses (20-40 mg/kg) cause renal, liver and lung damage with respiratory failure within 2-3 weeks; high doses (>40 mg/kg) cause pulmonary fibroplasia, respiratory failure, and death within 1-7 days. [ACGIH] Classified as highly toxic, paraquat may be used only by certified applicators. [EXTOXNET] Prolonged contact will cause blistering of skin. Poisoning usually occurs after toxic ingestion, e.g., attempted suicide. [EPA Pesticides] Phototoxic contact dermatitis reported in farmworkers; [Kanerva, p. 1823] A multigenerational study in rats given 100 ppm or 300 ppm dietary paraquat showed no effects on fertility or neonatal morbidity and mortality. In mice, maternal feeding with 125 ppm paraquat caused increased mortality in pups that was related to lung injury. [ACGIH] Among the many herbicides in use, only the bipyridyl compounds have appeared to produce hepatic injury in humans. Even these agents have produced hepatic injury only as the result of ingestion of large amounts, not because of environmental contamination and questionably as the result of occupational exposures. [Zimmerman, p. 415] Paraquat has a chemical structure similar to MPTP, but animal studies have failed to show that paraquat causes parkinsonism. [Rosenstock, p. 1111] See Paraquat.

PARAQUAT DICHLORIDE is stable in acidic media, but unstable in alkaline media. It is photochemically decomposed by UV irradiation in aqueous solutions and is rapidly inactivated by soil. The neat chemical may be sensitive to light. This compound is corrosive to metal and it can react with strong acids, bases, and oxidizing agents. It is hydrolyzed by alkali compounds and it is inactivated by inert clays and anionic surfactants. (NTP, 1992)

This material is a bipyridilium compound. Procedures for bipyridilium pesticides are as follows. Small fires: dry chemical, carbon dioxide, water spray, or foam. Large fires: water spray, fog, or foam. 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. (EPA, 1998)

In case of fire in the surroundings, use appropriate extinguishing media.

Fresh air, rest. Refer immediately for medical attention.

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

Rinse with plenty of water for several minutes (remove contact lenses if easily possible). Refer immediately for medical attention.

Rinse mouth. Give one or two glasses of water to drink. Give a slurry of activated charcoal in water to drink. Refer immediately for medical attention.

Warning: Effects occur in two stages, immediate and delayed. Caution is advised. Exposure to paraquat may be fatal; there is no effective antidote.；Signs and Symptoms of Acute Paraquat Exposure: Signs and symptoms of acute exposure to paraquat may be severe and include nausea, vomiting, diarrhea, and abdominal pain. A burning sensation of the mouth and esophagus with possible ulceration may occur following ingestion. Eye exposure may result in corneal opacification (cloudiness). Dermatitis and nail atrophy may occur following dermal contact. Delayed effects include transient reversible liver injury, acute renal failure, and progressive pulmonary fibrosis with associated dyspnea (shortness of breath) and pulmonary edema.；Emergency Life-Support Procedures: Acute exposure to paraquat 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 paraquat.；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 performance of other invasive procedures.；4. RUSH to a health care facility.；Dermal/Eye Exposure:；1. Remove victims from exposure. Emergency personnel should avoid self- exposure to paraquat.；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 performance of other invasive procedures.；7. RUSH 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 performance of other invasive procedures.；3. Vomiting may be induced with syrup of Ipecac. If elapsed time since ingestion of paraquat is unknown or suspected to be greater than 30 minutes, do not induce vomiting and proceed to Step

(General first aid procedures)；Eye: Irrigate immediately - If this chemical contacts the eyes, immediately wash (irrigate) the eyes with large amounts of water, occasionally lifting the lower and upper lids. Get medical attention immediately.；Skin: Water flush immediately - If this chemical contacts the skin, immediately flush the contaminated skin with water. If this chemical penetrates the clothing, immediately remove the clothing and flush the skin with water. Get medical attention promptly.；Breathing: Respiratory support；Swallow: Medical attention immediately - If this chemical has been swallowed, get medical attention immediately.

(Non-Specific -- Bipyridilium Pesticide) Keep unnecessary people away; isolate hazard area and deny entry. Stay upwind; keep out of low areas. Ventilate closed spaces before entering them. Remove and isolate contaminated clothing at the site. If water pollution occurs, notify appropriate authorities. 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 container and cover; move containers from spill area.；Large spills: dike far ahead of spill for later disposal. (EPA, 1998)

Consult an expert! Personal protection: chemical protection suit including self-contained breathing apparatus. Do NOT let this chemical enter the environment. Collect leaking and spilled liquid in sealable containers as far as possible. Absorb remaining liquid in sand or inert absorbent. Then store and dispose of according to local regulations. 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.

Excerpt from ERG Guide 151 [Substances - Toxic (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 tank car or highway tank 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, 2024)

In case of oral exposure, administer charcoal as a slurry. Consider after ingestion of a potentially life-threatening amount of poison if it can be performed soon after ingestion. The treatment is symptomatic and supportive. In case of eye exposure, irrigate exposed eyes with copious amounts of room temperature water for at least 15 minutes. In case of dermal exposure, remove contaminated clothing and jewellery. Wash the skin, including hair and nails, vigorously; do repeated soap washings. Discard contaminated clothing. (T36)

Respiratory

Eyes, skin, respiratory system, heart, liver, kidneys, gastrointestinal tract

It can cause temporary damage to nails and if swalloed, may cause nose bleeding. Long term exposures to paraquat would most likely cause lung and eye damage. Some suspect a possible link to a greater incidence of Parkinson's disease. Pancreatitis may develop in some cases of acute. Paraquat is caustic to the oral, esophageal, and gastric mucosa (T36, A545, L421).

Occupational hepatotoxin - Secondary hepatotoxins: the potential for toxic effect in the occupational setting is based on cases of poisoning by human ingestion or animal experimentation.；Nephrotoxin - The chemical is potentially toxic to the kidneys in the occupational setting.；Dermatotoxin - Skin burns.；Toxic Pneumonitis - Inflammation of the lungs induced by inhalation of metal fumes or toxic gases and vapors.；Fibrogenic - Inducing tissue injury and fibrosis (scarring).；ACGIH Carcinogen - Not Classifiable.

The substance can be absorbed into the body by inhalation of its aerosol, through the skin and by ingestion.

inhalation, skin absorption, ingestion, skin and/or eye contact

Inhalation (T44) ; oral (T44) ; eye contat (T44) ; dermal (T44)

The mechanisms of the toxic effects of paraquat are largely the result of a metabolically catalyzed single electron oxidation reduction reaction, resulting in depletion of cellular NADPH and the generation of potentially toxic forms of oxygen such as the superoxide radical (A607). Recent studies have demonstrated paraquat cytotoxicity occurs in the mitochondria and particularly in mitochondrial-rich tissues. The mitochondrial NADH-dependent PQ reductase containing a voltage-dependent anion channel 1 (VDAC1) appears to be largely responsible for paraquat cytotoxicity. When mitochondria are incubated with NADH and paraquat, the superoxide anion is produced, and the mitochondria rupture. Ruptured mitochondria lead to rapid cell death (A3102).

Cough. Sore throat. Headache. Nosebleeds.

Redness.

Redness. Burning sensation. Pain.

Sore throat. Abdominal pain. Nausea. Vomiting. Diarrhoea.

irritation eyes, skin, nose, throat, respiratory system; epistaxis (nosebleed); dermatitis; fingernail damage; irritation gastrointestinal tract; heart, liver, kidney damage

Eye or skin irritation; hypotension may develop after large ingestion; epistaxis and sore throat may develop after inhalation. Nausea, vomiting, diarrhea, and abdominal pain are common (T36).

The substance is very toxic to aquatic organisms. The substance may cause long-term effects in the aquatic environment. This substance does enter the environment under normal use. Great care, however, should be taken to avoid any additional release, for example through inappropriate disposal.

Paraquat

Respiratory

4.5 x 10 ^-3 mg/kg-day

LCLo (rat) = 1 mg/m3/6H for respirable dust;

LD50: 150 mg/kg (Oral, Rat) (L1008) LD50: >480 mg/kg (Dermal, Rabbit) (L1008)

Hazard Traits - Hazard Trait Undefined；Authoritative List - CECBP - Priority Chemicals；Report - if used as a fragrance or flavor ingredient

Paraquat dichloride is listed in the dataset of EPA Human Health Benchmarks for Pesticides under the Safe Drinking Water Act (40 eCFR 141)

Status: Active Update: 26-01-2023 https://echa.europa.eu/registration-dossier/-/registered-dossier/29834

Paraquat dichloride: Does not have an individual approval but may be used as a component in a product covered by a group standard. It is not approved for use as a chemical in its own right.

The New Jersey Worker and Community Right to Know Act requires public and private employers to provide information about hazardous substances at their workplaces. (N.J.S.A. 34:5A-1 et. seq.)

Paraquat is poorly absorbed after oral exposure. It is not metabolized but is reduced to an unstable free radical which is then re-oxidized to reform the cation and produce a superoxide anion. It is excreted moslty in the urine,and in small fraction also in the feces (A606, L1008).

Used as a contact herbicide on weeds; [EXTOXNET] Used in animal experiments as a model of Parkinson's syndrome at doses several orders of magnitude greater than occupational exposure levels; [PMID 16217247]

Farming (Pesticides) [Category: Industry]

Paraquat is used as a quaternary ammonium herbicide; one of the most widely used herbicides in the world. It is also often used in science to catalyze the formation of reactive oxygen species (ROS). (L421).