NIOSH Pocket Guide to Chemical Hazards

Sodium cyanide (as CN)

CAS 143-33-9


RTECS VZ7525000
Synonyms & Trade Names
Sodium salt of hydrocyanic acid
DOT ID & Guide
1689 157 (solid)
3413 157 (solution)


NIOSH REL*: C 5 mg/m3 (4.7 ppm) [10-minute] [*Note: The REL also applies to other cyanides (as CN) except Hydrogen cyanide.]
OSHA PEL*: TWA 5 mg/m3 [*Note: The PEL also applies to other cyanides (as CN) except Hydrogen cyanide.]
IDLH 25 mg/m3 (as CN) See: cyanides Conversion
Physical Description
White, granular or crystalline solid with a faint, almond-like odor.
MW: 49.0
BP: 2725°F
MLT: 1047°F
Sol(77°F): 58%
VP: 0 mmHg (approx)

Sp.Gr: 1.60
Fl.P: NA

Noncombustible Solid, but contact with acids releases highly flammable hydrogen cyanide.
Incompatibilities & Reactivities
Strong oxidizers (such as acids, acid salts, chlorates & nitrates) [Note: Absorbs moisture from the air forming a syrup.]
Measurement Methods
NIOSH 6010, 7904
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: Daily
Provide: Eyewash, Quick drench
First Aid (See procedures)
Eye: Irrigate immediately
Skin: Soap wash immediately
Breathing: Respiratory support
Swallow: Medical attention immediately
Important additional information about respirator selection
Respirator Recommendations NIOSH/OSHA
Up to 25 mg/m3:
(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 canister providing protection against the compound of concern and 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; asphyxia; lassitude (weakness, exhaustion), headache, confusion; nausea, vomiting; increased respiratory rate; slow gasping respiration; thyroid, blood changes
Target Organs Eyes, skin, cardiovascular system, central nervous system, thyroid, blood
See also: INTRODUCTION   See ICSC CARD: 1118