| Agent Name |
Paraquat dichloride |
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| CAS Number |
1910-42-5 |
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| Formula |
C12-H14-N2.2Cl |
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| Major Category |
Pesticides |
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| Synonyms |
1,1'-Dimethyl-4,4'-bipyridinium dichloride; N,N'-Dimethyl-4,4'-bipyridinium dichloride; Paraquat chloride; Paraquat dichloride [Note: Paraquat is a cation (C12H14N2++; 1,1-Dimethyl-4,4-bipyridinium ion); the commercial product is the dichloride salt of paraquat.]; [NIOSH] Bipyridinium, 1,1'-dimethyl-4,4'-, dichloride; Cekuquat; Crisquat; Dexuron; Dimethyl viologen chloride; Dwuchlorek 1,1'-dwumetylo-4,4'-dwupirydyniowy [Polish]; Esgram; Galokson; Goldquat 276; Gramixel; Gramoxone; Gramoxone D; Gramoxone S; Gramoxone W; Gramoxone dichloride; Gramuron; Herbaxon; Herboxone; Methyl viologen; Methyl viologen (reduced); Methyl viologen dichloride; Methylviologen chloride; OK 622; Ortho paraquat CL; Parakwat [Polish]; Paraquat CL; Pathclear; Pillarquat; Pillarxone; Toxer total; Viologen, methyl-; [ChemIDplus] |
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| Category |
Herbicides, Bipyridyl |
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| Description |
Yellow solid with a faint, ammonia-like odor. [herbicide] [Note: Paraquat may also be found commercially as a methyl sulfate salt C12H14N2+2CH3SO4.]; [NIOSH] |
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| Sources/Uses |
Used as a contact herbicide on weeds; [EXTOXNET] |
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| Comments |
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] Acute poisoning causes pulmonary edema, liver injury, and renal failure. Pulmonary fibrosis, starting one to three weeks after ingestion, may be seen in survivors. [ACGIH] Allergic and photoallergic contact dermatitis reported in farmworkers; [Kanerva, p. 1165] Paraquat causes fetal losses in high-dose reproductive studies of animals. In studies of Mallard embryos, it causes birth defects. [Frazier, p. 242-3] "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] |
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| Reference Link |
EXTOXNET PIP - PARAQUAT |
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| Exposure Assessment |
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| Skin Designation (ACGIH) |
No |
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| PEL (OSHA) |
0.5 mg/m3, respirable dust |
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| MAK |
0.1 mg/m3, inhalable fraction |
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| IDLH (NIOSH) |
1 mg/m3 |
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| Excerpts from Documentation for IDLHs |
Human data: It has been stated that the high acute inhalation toxicity of paraquat is dependent wholly on the size of the particulate, with respirable sizes (i.e., <5 micrometer mass median diameter) found to be 5 to 6 times more toxic than nonrespirable dusts [McElligo 1965]. It has been reported that under paraquat spraying conditions particle sizes appear to be nonrespirable [Swan 1969]. |
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| Vapor Pressure |
1 x 10 -07 mm Hg |
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| Lethal Concentration |
LCLo (rats) = 1 mg/m3/6H for respirable dust; |
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| Explanatory Notes |
ACGIH has TLV for paraquat (4685-14-7) = 0.5 mg/m3 ( total particulate) and 0.1 (respirable fraction); LCLo (rats) = 6400 mg/m3/6H for nonrespirable dust; |
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| Half Life |
Animal studies: less than 6 hours; other animal studies have found measurable paraquat 26 days after ingestion; [TDR, p. 991] |
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| Reference Link |
Phototoxic contact dermatitis with toxic hepatitis due to the percutaneous absorption of paraquat |
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| Adverse Effects |
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| Toxic Pneumonitis |
Yes |
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| Fibrogenic |
Yes |
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| Dermatotoxin |
Skin Burns |
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| Hepatotoxin |
Hepatotoxin, Secondary |
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| Nephrotoxin |
Yes |
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| Reproductive Toxin |
Yes |
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| Links to Other NLM Databases |
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| Health Studies |
Human Health Effects from Hazardous Substances Data Bank: PARAQUAT
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