Agent Name

Paraquat

CAS Number

4685-14-7

Formula

C12-H14-N2

Major Category

Pesticides

Synonyms

1,1'-Dimethyl-4,4'-bipyridinium; 1,1'-Dimethyl-4,4'-bipyridinium cation; 1,1'-Dimethyl-4,4'-bipyridinium salt; 1,1'-Dimethyl-4,4'-bipyridyldiylium; 1,1'-Dimethyl-4,4'-bipyridyldiylium ion (8CI)(9CI); Dextrone; Dextrone X; Dimethyl viologen; Methyl viologen (2+); Methyl viologen ion(2+); N,N'-Dimethyl-4,4'-bipyridinium; N,N'-Dimethyl-4,4'-bipyridinium dication; N,N'-Dimethyl-gamma,gamma'-dipyridylium; Paraquat dication; Paraquat ion; Spraytop-graze; Starfire; Weedol; 4,4'-Bipyridinium, 1,1'-dimethyl-; [ChemIDplus]

Category

Herbicides, Bipyridyl

Description

Yellow, odorless solid; [HSDB] Technical grade is a dark red solution; [CHEMINFO] Commercially available as an aqueous solution with surfactants; [ACGIH]

Sources/Uses

Used as a contact herbicide for weed control in grass seed crops and orchards; a crop desiccant and defoliant on cotton and potato vines; harvest aid for soybeans; [HSDB] A quick-acting herbicide; [ACGIH]

Comments

Toxicity is due to the cation (1,1'-dimethyl-4,4'-bipyridium) with all salts having equivalent toxicity. The dichloride salt is colorless, odorless, and soluble in water. Animal experiments show that it is not absorbed through intact skin, but one case of occupational poisoning by skin absorption of undiluted paraquat was reported. In typical spraying, farmworkers are not exposed to aerosol particles below respirable size, and systemic absorption was insignificant in two field studies. [ACGIH] A skin, eye, and mucous membrane irritant; [HSDB] "Contact with concentrated solutions causes irritation of the skin, cracking and shedding of the nails, and delayed healing of cuts and wounds."; [ChemIDplus] Highly toxic via ingestion, inhalation, and skin absorption; [Hawley] See "Paraquat dichloride."

Exposure Assessment
Skin Designation (ACGIH)

Insufficient data

TLV (ACGIH)

0.5 mg/m3, 0.1 mg/m3 (respirable fraction)

PEL (OSHA)

0.5 mg/m3, respirable dust

Vapor Pressure

1.0E-7 mm Hg

Explanatory Notes

See "2017 Notice of Intended Changes." [TLVs and BEIs]

Adverse Effects
Skin Sensitizer

Yes

Toxic Pneumonitis

Yes

Fibrogenic

Yes

Hepatotoxin

Hepatotoxin, Secondary

Nephrotoxin

Yes

Reproductive Toxin

Yes

Dermatotoxin

Skin Burns

Links to Other NLM Databases
Health Studies

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Toxicity Information

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Chemical Information

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Biomedical References

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Related Information in HazMap
Diseases

Occupational diseases associated with exposure to this agent:

Processes

Industrial Processes with risk of exposure: