Agent Name

Potassium cyanide

CAS Number




Major Category

Toxic Gases & Vapors


Cyanide of potassium; Cyanure de potassium [French]; Hydrocyanic acid, potassium salt; Kalium cyanid [German]; M-44 capsules (potassium cyanide); Potassium cyanide; Potassium cyanide (K(CN)); [ChemIDplus] UN1680




White, granular or crystalline solid with a faint, almond-like odor; [NIOSH] Deliquescent; [CHEMINFO]


Used mainly for silver plating; Also used in steel hardening, gold and silver extraction, and fumigation (fruit trees, ships, railroad cars, and warehouses); [HSDB] Used in photography (reducer); []


There are two common scenarios for cyanide poisoning in the industrial setting: 1) mixing acid and cyanide solutions, and 2) pouring cyanide wastes into non-alkaline solutions. Mixing cyanide salts with water, e.g., showering in clothes contaminated with cyanides, will generate hydrogen cyanide gas. Dermal absorption of cyanide salts deposited on large areas of skin can result in fatal poisoning. [Sullivan, p. 705-6] The moist solid form is caustic to skin. [CHRIS] A severe skin, eye, and respiratory tract irritant; [ICSC] "The substance may cause effects on the cellular respiration , resulting in convulsions and unconsciousness; The substance may have effects on the thyroid"; [ICSC]


"This chemical ingredient is not found in any products." [National Pesticide Information Retrieval System]

Exposure Assessment
Skin Designation (ACGIH)


Dangerous When Wet

Yes - A material that, by contact with water, is liable to become spontaneously flammable or to give off flammable or toxic gas at a rate greater than 1 L per kilogram of the material, per hour; [ERG 2004]

Ceiling (ACGIH)

5 mg/m3, as CN


5 mg/m3, as CN


5 mg/m3, as CN, inhalable fraction


25 mg/m3, as CN

Excerpts from Documentation for IDLHs

Human data: Absorption of the alkali cyanides in amounts as low as 50 to 100 mg from a single, instantaneous dose may be followed by immediate collapse and cessation of respiration [Clayton and Clayton 1982]. It has been stated that although the fatal oral dose will vary considerably, depending on whether or not food is present in the stomach, it is probably in the order of 1 to 2 mg/kg [Clayton and Clayton]. [Note: An oral dose of 50 to 100 mg or 1 to 2 mg/kg is equivalent to a 70kg worker being exposed to about 50 mg/m3 (as CN) for 30 minutes, assuming a breathing rate of 50 liters per minute and 100% absorption.]

Explanatory Notes

For TLV, see "Hydrogen cyanide."

Reference Link

ATSDR - ToxFAQs - Cyanide

Adverse Effects
Other Poison

Chemical Asphyxiant


Skin Burns

Links to Other NLM Databases
Health Studies

Human Health Effects from Hazardous Substances Data Bank:

Toxicity Information


Chemical Information

Search ChemIDplus

Biomedical References

Search PubMed

Related Information in HazMap

Occupational diseases associated with exposure to this agent:


Industrial Processes with risk of exposure: