NIOSH Pocket Guide to Chemical Hazards

Paraquat (Paraquat dichloride)

CAS 1910-42-5

CH3(C5H4N)2CH3 • 2Cl

RTECS DW2275000
Synonyms & Trade Names
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.]
DOT ID & Guide


NIOSH REL: TWA 0.1 mg/m3 (resp) [skin]
OSHA PEL†: TWA 0.5 mg/m3 (resp) [skin]
IDLH 1 mg/m3 See: 1910425 Conversion
Physical Description
Yellow solid with a faint, ammonia-like odor. [herbicide] [Note: Paraquat may also be found commercially as a methyl sulfate salt C12H14N2 • 2CH3SO4.]
MW: 257.2
BP: Decomposes
MLT: 572°F (Decomposes)
Sol: Miscible
VP: <0.0000001 mmHg
IP: ?

Sp.Gr: 1.24
Fl.P: NA

Noncombustible Solid
Incompatibilities & Reactivities
Strong oxidizers, alkylaryl-sulfonate wetting agents [Note: Corrosive to metals. Decomposes in presence of ultraviolet light.]
Measurement Methods
NIOSH 5003
See: NMAM or OSHA Methods
Personal Protection & Sanitation (See protection)
Skin: Prevent skin contact
Eyes: Prevent eye contact
Wash skin: When contaminated
Remove: When wet or contaminated
Change: No recommendation
Provide: Quick drench
First Aid (See procedures)
Eye: Irrigate immediately
Skin: Water flush immediately
Breathing: Respiratory support
Swallow: Medical attention immediately
Important additional information about respirator selection
Respirator Recommendations NIOSH
Up to 1 mg/m3:
(APF = 10) Any air-purifying half-mask respirator with organic vapor cartridge(s) in combination with an N95, R95, or P95 filter. The following filters may also be used: N99, R99, P99, N100, R100, P100. Click here for information on selection of N, R, or P filters.*
(APF = 25) Any powered air-purifying respirator with an organic vapor cartridge in combination with a high-efficiency particulate filter.*
(APF = 10) Any supplied-air respirator*
(APF = 50) Any self-contained breathing apparatus with a full facepiece
Emergency or planned entry into unknown concentrations or IDLH conditions:
(APF = 10,000) Any self-contained breathing apparatus that has a full facepiece and is operated in a pressure-demand or other positive-pressure mode
(APF = 10,000) Any supplied-air respirator that has a full facepiece and is operated in a pressure-demand or other positive-pressure mode in combination with an auxiliary self-contained positive-pressure breathing apparatus
(APF = 50) Any air-purifying, full-facepiece respirator (gas mask) with a chin-style, front- or back-mounted organic vapor canister having an N100, R100, or P100 filter. Click here for information on selection of N, R, or P filters./Any appropriate escape-type, self-contained breathing apparatus
Exposure Routes inhalation, skin absorption, ingestion, skin and/or eye contact
Symptoms Irritation eyes, skin, nose, throat, respiratory system; epistaxis (nosebleed); dermatitis; fingernail damage; irritation gastrointestinal tract; heart, liver, kidney damage
Target Organs Eyes, skin, respiratory system, heart, liver, kidneys, gastrointestinal tract
See also: INTRODUCTION   See ICSC CARD: 0005   See MEDICAL TESTS: 0173