Potassium Cyanide

H290 (24%): May be corrosive to metals [Warning Corrosive to Metals]

H300+H310+H330 (34.8%): Fatal if swallowed, in contact with skin or if inhaled [Danger Acute toxicity, oral; acute toxicity, dermal; acute toxicity, inhalation]

H300 (99.8%): Fatal if swallowed [Danger Acute toxicity, oral]

H310 (99.8%): Fatal in contact with skin [Danger Acute toxicity, dermal]

H315 (11.1%): Causes skin irritation [Warning Skin corrosion/irritation]

H318 (10.4%): Causes serious eye damage [Danger Serious eye damage/eye irritation]

H330 (99.8%): Fatal if inhaled [Danger Acute toxicity, inhalation]

H370 (18.1%): Causes damage to organs [Danger Specific target organ toxicity, single exposure]

H372 (57.4%): Causes damage to organs through prolonged or repeated exposure [Danger Specific target organ toxicity, repeated exposure]

H400 (99.8%): Very toxic to aquatic life [Warning Hazardous to the aquatic environment, acute hazard]

H410 (99.5%): Very toxic to aquatic life with long lasting effects [Warning Hazardous to the aquatic environment, long-term hazard]

P234, P260, P262, P264, P264+P265, P270, P271, P273, P280, P284, P301+P316, P302+P352, P304+P340, P305+P354+P338, P308+P316, P316, P317, P319, P320, P321, P330, P332+P317, P361+P364, P362+P364, P390, P391, P403+P233, P405, P406, and P501 (click each P-code to see the statement)

Aggregated GHS information provided per 575 reports by companies from 30 notifications to the ECHA C&L Inventory. Each notification may be associated with multiple companies.

Information may vary between notifications depending on impurities, additives, and other factors. The percentage value in parenthesis indicates the notified classification ratio from companies that provide hazard codes. Only hazard codes with percentage values above 10% are shown. For more detailed information, please visit ECHA C&L website.

H300: Fatal if swallowed [Danger Acute toxicity, oral]

H310: Fatal in contact with skin [Danger Acute toxicity, dermal]

H315: Causes skin irritation [Warning Skin corrosion/irritation]

H319: Causes serious eye irritation [Warning Serious eye damage/eye irritation]

H335: May cause respiratory irritation [Warning Specific target organ toxicity, single exposure; Respiratory tract irritation]

H361: Suspected of damaging fertility or the unborn child [Warning Reproductive toxicity]

H370: Causes damage to organs [Danger Specific target organ toxicity, single exposure]

H372: Causes damage to organs through prolonged or repeated exposure [Danger Specific target organ toxicity, repeated exposure]

H400: Very toxic to aquatic life [Warning Hazardous to the aquatic environment, acute hazard]

H412: Harmful to aquatic life with long lasting effects [Hazardous to the aquatic environment, long-term hazard]

P203, P260, P261, P262, P264, P264+P265, P270, P271, P273, P280, P301+P316, P302+P352, P304+P340, P305+P351+P338, P308+P316, P316, P318, P319, P321, P330, P332+P317, P337+P317, P361+P364, P362+P364, P391, P403+P233, P405, and P501 (click each P-code to see the statement)

H316: Causes mild skin irritation [Warning Skin corrosion/irritation]

H371: May cause damage to organs [Warning Specific target organ toxicity, single exposure]

P260, P262, P264, P264+P265, P270, P280, P301+P316, P302+P352, P305+P351+P338, P308+P316, P316, P319, P321, P330, P332+P317, P337+P317, P361+P364, P405, and P501 (click each P-code to see the statement)

H330: Fatal if inhaled [Danger Acute toxicity, inhalation]

P260, P262, P264, P270, P271, P280, P284, P301+P316, P302+P352, P304+P340, P316, P320, P321, P330, P332+P317, P361+P364, P362+P364, P403+P233, P405, and P501 (click each P-code to see the statement)

Administration of oxygen may be needed. Fresh air, rest. No mouth-to-mouth artificial respiration. Refer immediately for medical attention.

Wear protective gloves when administering first aid. Remove contaminated clothes. Rinse skin with plenty of water or shower. Refer immediately for medical attention .

First rinse with plenty of water for several minutes (remove contact lenses if easily possible), then refer for medical attention.

Rinse mouth. Administration of oxygen may be needed. NO mouth-to-mouth artificial respiration. Do NOT induce vomiting. Refer immediately for medical attention.

Warning: Effects may be delayed. Caution is advised. Vital signs should be monitored closely. Heart palpitation may occur within minutes after exposure.

Signs and Symptoms of Acute Potassium Cyanide Exposure: Signs and symptoms of acute exposure to potassium cyanide may include hypertension (high blood pressure) and tachycardia (rapid heart rate), followed by hypotension (low blood pressure) and bradycardia (slow heart rate). Cardiac arrhythmias and other cardiac abnormalities are common. Cyanosis (blue tint to the skin and mucous membranes), and cherry-red or bloody mucous membranes may appear. Tachypnea (rapid respiratory rate) may be followed by respiratory depression. Lung hemorrhage and pulmonary edema may occur. Headache, vertigo (dizziness), agitation, and giddiness may precede combative behavior, convulsions, paralysis, protruding eyeballs, dilated and unreactive pupils, and coma. Potassium cyanide is irritating to the skin, eyes, and mucous membranes. Lacrimation (tearing) and a burning sensation of the mouth and throat are common. Salivation, nausea, and vomiting may also occur.

Emergency Life-Support Procedures: Acute exposure to potassium cyanide may require decontamination and life support for the victims. All exposed persons should be transported to a health care facility as quickly as possible. Emergency personnel should wear protective clothing appropriate to the type and degree of contamination. Air- purifying or supplied-air respiratory equipment should also be worn, as necessary. Rescue vehicles should carry supplies such as plastic sheeting and disposable plastic bags to assist in preventing spread of contamination.

Inhalation Exposure:

1. Move victims to fresh air. Emergency personnel should avoid self-exposure to potassium cyanide.

2. Evaluate vital signs including pulse and respiratory rate, and note any trauma. If no pulse is detected, provide CPR. If not breathing, provide artificial respiration. IMMEDIATELY begin administering 100% oxygen to all victims. Monitor victims for respiratory distress.Warning: To prevent self-poisoning, avoid mouth-to-mouth breathing; use a forced-oxygen mask. Direct oral contact with potassium cyanide- contaminated persons or their gastric contents can result in self- poisoning.

3. RUSH to a health care facility!

4. Obtain authorization and/or further instructions from the local hospital for administration of an antidote or performance of other invasive procedures.

Dermal/Eye Exposure:

1. Remove victims from exposure. Emergency personnel should avoid self- exposure to potassium cyanide.

4. Remove contaminated clothing as soon as possible.

5. If eye exposure has occurred, eyes must be flushed with lukewarm water for at least 15 minutes.

6. Wash exposed skin areas twice with soap and water.

7. Obtain authorization and/or further instructions from the local hospital for administration of an antidote or performance of other invasive procedures.

Ingestion Exposure:

1. Evaluate vital signs including pulse and respiratory rate, and note any trauma. If no pulse is detected, provide CPR. If not breathing, provide artificial respiration. IMMEDIATELY begin administering 100% oxygen to all victims. Monitor victims for respiratory distress.Warning: To prevent self-poisoning, avoid mouth-to-mouth breathing; use a forced-oxygen mask. Direct oral contact with potassium cyanide- contaminated persons or their gastric contents can result in self- poisoning.

2. RUSH to a health care facility!

3. DO NOT induce vomiting. Ipecac is not recommended for ingestion of potassium cyanide.

5. Activated charcoal may be administered if victims are conscious and alert. Use 15 to 30 g (1/2 to 1 oz) for children, 50 to 100 g (1-3/4 to 3-1/2 oz) for adults, with 125 to 250 mL (1/2 to 1 cup) of water.

6. Promote excretion by administering a saline cathartic or sorbitol to conscious and alert victims. Children require 15 to 30 g (1/2 to 1 oz) of cathartic; 50 to 100 g (1-3/4 to 3-1/2 oz) is recommended for adults. (EPA, 1998)

Excerpt from ERG Guide 157 [Substances - Toxic and/or Corrosive (Non-Combustible / Water-Sensitive)]:

Refer to the "General First Aid" section. Specific First Aid: For corrosives, in case of contact, immediately flush skin or eyes with running water for at least 30 minutes. Additional flushing may be required. In case of skin contact with Hydrofluoric acid (UN1790), if calcium gluconate gel is available, rinse 5 minutes, then apply gel. Otherwise, continue rinsing until medical treatment is available. (ERG, 2024)

General First Aid:

· Call 911 or emergency medical service.

· Ensure that medical personnel are aware of the material(s) involved, take precautions to protect themselves and avoid contamination.

· Move victim to fresh air if it can be done safely.

· Administer oxygen if breathing is difficult.

· If victim is not breathing:

-- DO NOT perform mouth-to-mouth resuscitation; the victim may have ingested or inhaled the substance.

-- If equipped and pulse detected, wash face and mouth, then give artificial respiration using a proper respiratory medical device (bag-valve mask, pocket mask equipped with a one-way valve or other device).

-- If no pulse detected or no respiratory medical device available, provide continuous compressions. Conduct a pulse check every two minutes or monitor for any signs of spontaneous respirations.

· Remove and isolate contaminated clothing and shoes.

· For minor skin contact, avoid spreading material on unaffected skin.

· In case of contact with substance, remove immediately by flushing skin or eyes with running water for at least 20 minutes.

· For severe burns, immediate medical attention is required.

· Effects of exposure (inhalation, ingestion, or skin contact) to substance may be delayed.

Wear full protective clothing. Wear positive pressure breathing apparatus and special protective clothing. Move container from fire area if you can do it without risk. Fight fire from maximum distance. Dike fire control water for later disposal; do not scatter the material.

Water may be used on fire in an area containing potassium cyanide. Extinguish with dry chemical, carbon dioxide, water spray, fog, or foam. (EPA, 1998)

Excerpt from ERG Guide 157 [Substances - Toxic and/or Corrosive (Non-Combustible / Water-Sensitive)]:

Note: Some foams will react with the material and release corrosive/toxic gases.

SMALL FIRE: CO2 (except for Cyanides), dry chemical, dry sand, alcohol-resistant foam.

LARGE FIRE: Water spray, fog or alcohol-resistant foam. If it can be done safely, move undamaged containers away from the area around the fire. Avoid aiming straight or solid streams directly onto the product. Dike runoff from fire control for later disposal.

FIRE INVOLVING TANKS, RAIL TANK CARS OR HIGHWAY TANKS: Fight fire from maximum distance or use unmanned master stream devices or monitor nozzles. Do not get water inside containers. Cool containers with flooding quantities of water until well after fire is out. Withdraw immediately in case of rising sound from venting safety devices or discoloration of tank. ALWAYS stay away from tanks in direct contact with flames. (ERG, 2024)

NO hydrous agents. NO water. NO carbon dioxide. In case of fire in the surroundings, use appropriate extinguishing media. In case of fire: keep drums, etc., cool by spraying with water.

- Potassium cyanide is non-combustible.

- The agent itself does not burn, but it may decompose upon heating to produce corrosive and/or toxic fumes.

- Water-sensitive: Potassium cyanide releases highly flammable and toxic hydrogen cyanide gas on contact with water or damp air and in a fire.

- Note: Most foams will react with the agent and release corrosive/toxic gases.

- For small fires, do not use carbon dioxide; use dry chemical, dry sand, or alcohol-resistant foam.

- For large fires, use water spray, fog, or alcohol-resistant foam. Move containers from the fire area if it is possible to do so without risk to personnel. Use water spray or fog; do not use straight streams. Dike fire control water for later disposal; do not scatter the material.

- For fire involving tanks or car/trailer loads, fight the fire from maximum distance or use unmanned hose holders or monitor nozzles. Do not get water inside containers. Cool containers with flooding quantities of water until well after the fire is out. Withdraw immediately in case of rising sound from venting safety devices or discoloration of tanks. Always stay away from tanks engulfed in fire.

- Run-off from fire control or dilution water may be corrosive and/or toxic, and it may cause pollution.

- If the situation allows, control and properly dispose of run-off (effluent).

Do not use carbon dioxide extinguisher. Extinguish fire using agent suitable for surrounding fire. Water may be used on nearby fires not involving potassium cyanide. Use water spray to keep fire-exposed containers cool. Use alkali dry chemical.

Carbon dioxide fire extinguishers must not be used where cyanide salts are present. /Cyanide salts/

If material involved in fire: Extinguish fire using agent suitable for type of surrounding fire. (Material itself does not burn or burns with difficulty.) Use water in flooding quantities as fog. Cool all affected containers with flooding quantities of water. Use "alcohol" foam, dry chemical, or carbon dioxide. Use water spray to knock-down vapors. /Potassium cyanide solution/

If material involved in fire: Extinguish fire using agent suitable for type of surrounding fire. (Material itself does not burn or burns with difficulty.) Use foam, dry chemical, or carbon dioxide. Do not use water on material itself. If large quantities of combustibles are involved, use water in flooding quantities as spray and fog. Use water spray to knock-down vapors. /Potassium cyandie, solid/

· CALL 911. Then call emergency response telephone number on shipping paper. If shipping paper not available or no answer, refer to appropriate telephone number listed on the inside back cover.

· Keep unauthorized personnel away.

· Stay upwind, uphill and/or upstream.

· Ventilate closed spaces before entering, but only if properly trained and equipped.

· ELIMINATE all ignition sources (no smoking, flares, sparks or flames) from immediate area.

· All equipment used when handling the product must be grounded.

· Do not touch damaged containers or spilled material unless wearing appropriate protective clothing.

· Stop leak if you can do it without risk.

· A vapor-suppressing foam may be used to reduce vapors.

· DO NOT GET WATER INSIDE CONTAINERS.

· Use water spray to reduce vapors or divert vapor cloud drift. Avoid allowing water runoff to contact spilled material.

· Prevent entry into waterways, sewers, basements or confined areas.

Small Spill

· Cover with DRY earth, DRY sand or other non-combustible material followed with plastic sheet to minimize spreading or contact with rain.

· Use clean, non-sparking tools to collect material and place it into loosely covered plastic containers for later disposal.

HCN - when spill Potassium cyanide, solid into water.

Excerpt from ERG Guide 157 [Substances - Toxic and/or Corrosive (Non-Combustible / Water-Sensitive)]:

IMMEDIATE PRECAUTIONARY MEASURE: Isolate spill or leak area in all directions for at least 50 meters (150 feet) for liquids and at least 25 meters (75 feet) for solids.

SPILL: See ERG Table 1 - Initial Isolation and Protective Action Distances on the UN/NA 1680 datasheet.

FIRE: If tank, rail tank car or highway tank is involved in a fire, ISOLATE for 800 meters (1/2 mile) in all directions; also, consider initial evacuation for 800 meters (1/2 mile) in all directions. (ERG, 2024)

SPILL: Increase the immediate precautionary measure distance, in the downwind direction, as necessary.

Immediate precautionary measure

· Isolate spill or leak area in all directions for at least 50 meters (150 feet) for liquids and at least 25 meters (75 feet) for solids.

· For highlighted materials: see Table 1 - Initial Isolation and Protective Action Distances.

· For non-highlighted materials: increase the immediate precautionary measure distance, in the downwind direction, as necessary.

· If tank, rail tank car or highway tank is involved in a fire, ISOLATE for 800 meters (1/2 mile) in all directions; also, consider initial evacuation for 800 meters (1/2 mile) in all directions.

When spilled in water

Small spill:

- ISOLATE in all directions: 30 m (100 ft)

Large spill:

- ISOLATE in all directions: 60 m (200 ft)

- PROTECT people from downwind during DAY time: 0.1 km (0.1 mi)

- PROTECT people from downwind during NIGHT time: 0.1 km (0.1 mi)

- PROTECT people from downwind during DAY time: 0.2 km (0.1 mi)

- PROTECT people from downwind during NIGHT time: 0.7 km (0.4 mi)

Evacuate danger area! Consult an expert! Personal protection: complete protective clothing including self-contained breathing apparatus. Do NOT let this chemical enter the environment. Ventilation. Sweep spilled substance into covered dry, sealable, labelled containers. Cautiously neutralize remainder with sodium hypochlorite solution.

Spills of cyanide salts should be immediately and carefully cleaned up by shoveling the material into a proper container. Care must be exercised to minimize any dispersal of cyanide dust into the air. /Cyanide salts/

WASTE CYANIDE SALTS FROM CASE HARDENING OF STEEL ARE DESTROYED BY REACTING THE SALTS AT 650-700 °C WITH WASTE FERRIC HYDROXIDE SLUDGES FROM VARIOUS SOURCES. /CYANIDE SALTS/

REMOVAL OF COPPER, NICKEL, ZINC, CADMIUM AND CYANIDE FROM PLATING WASTEWATER BY ELECTROFLOTATION. /CYANIDES/

Keep water away from release. Flush spill area with hypochlorite solution. Cover in noncombustible material for proper disposal. Shovel into suitable dry container. Control runoff and isolate discharged material for proper disposal.

Excerpt from ERG Guide 157 [Substances - Toxic and/or Corrosive (Non-Combustible / Water-Sensitive)]:

ELIMINATE all ignition sources (no smoking, flares, sparks or flames) from immediate area. All equipment used when handling the product must be grounded. Do not touch damaged containers or spilled material unless wearing appropriate protective clothing. Stop leak if you can do it without risk. A vapor-suppressing foam may be used to reduce vapors. DO NOT GET WATER INSIDE CONTAINERS. Use water spray to reduce vapors or divert vapor cloud drift. Avoid allowing water runoff to contact spilled material. Prevent entry into waterways, sewers, basements or confined areas.

SMALL SPILL: Cover with DRY earth, DRY sand or other non-combustible material followed with plastic sheet to minimize spreading or contact with rain. Use clean, non-sparking tools to collect material and place it into loosely covered plastic containers for later disposal. (ERG, 2024)

Separated from strong oxidants, acids, food and feedstuffs, carbon dioxide and products containing water. Dry. Well closed. Keep in a well-ventilated room. Store in an area without drain or sewer access.

PROTECT FROM LIGHT.

ALL CONTAINERS OF CYANIDE SALTS SHOULD BE KEPT COVERED OR IN EXHAUST HOOD WHEN NOT IN USE. /CYANIDES/

Store in a cool, dry, well-ventilated location. Separate from water, acids, and carbon dioxide. Outside or detached storage in preferred.

Cyanide salts as solids must be stored in sealed or tightly closed containers. No hooks should be used in handling cyanide containers. ... Storage areas must be adequately ventilated to ensure that cyanide concentrations do not exceed the recommended workplace environmental limits. /Cyanide salts/

For more Storage Conditions (Complete) data for POTASSIUM CYANIDE (6 total), please visit the HSDB record page.

· Wear positive pressure self-contained breathing apparatus (SCBA).

· Wear chemical protective clothing that is specifically recommended by the manufacturer when there is NO RISK OF FIRE.

· Structural firefighters' protective clothing provides thermal protection but only limited chemical protection.

TIH (Toxic Inhalation Hazard) - Term used to describe gases and volatile liquids that are toxic when inhaled. Some are TIH materials themselves, e.g., chlorine, and some release TIH gases when spilled in water, e.g., chlorosilanes. [ERG 2016].

5.0 [mg/m3], as CN, inhalable fraction[German Research Foundation (DFG)]

AEGL 1: Notable discomfort, irritation, or certain asymptomatic non-sensory effects. However, the effects are not disabling and are transient and reversible upon cessation of exposure (Unit: mg/m3)

AEGL 2: Irreversible or other serious, long-lasting adverse health effects or an impaired ability to escape (Unit: mg/m3)

AEGL 3: Life-threatening health effects or death (Unit: mg/m3)

6.6 mg/m3

45 mg/m3

72 mg/m3

27 mg/m3

56 mg/m3

5.3 mg/m3

19 mg/m3

40 mg/m3

3.5 mg/m3

9.3 mg/m3

23 mg/m3

2.7 mg/m3

18 mg/m3

NOTE THAT VALUES ARE IN mg/m3, NOT ppm.

AEGLs Status: Final

5.3 [mg/m3]

19 [mg/m3]

40 [mg/m3]

C 5 mg/m3 (4.7 ppm) [10-minute] [*Note: The REL also applies to other cyanides (as CN) except Hydrogen cyanide.]

5.0 [mg/m3], as CN

TWA 5 mg/m3 [*Note: The PEL also applies to other cyanides (as CN) except Hydrogen cyanide.]

25 mg CN/m3 (NIOSH, 2024)

25.0 [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.]

25 mg/cu m (as CN)

25 mg/m3 (as CN)

See: cyanides

Ceiling limit: 5 mg/cu m, skin /Cyanide salts, as CN/

(ceiling value): 5 mg/m

· Note: Some foams will react with the material and release corrosive/toxic gases.

Small Fire

· CO2 (except for Cyanides), dry chemical, dry sand, alcohol-resistant foam.

Potassium cyanide appears as white amorphous lumps or a crystalline mass with a faint odor of bitter almonds. Density 1.52 g / cm3 Toxic by skin absorption through open wounds, by ingestion. Heating to decomposition produces toxic fumes. Used for gold and silver extraction, in chemical analysis, to make other chemicals, and as an insecticide.

Potassium cyanide solution is a clear colorless aqueous solution with a faint odor of bitter almonds. Can contain up to 50 g of potassium cyanide per 100 g of water at room temperature.

Other Solid; Large Crystals

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

HYGROSCOPIC CRYSTALS OR SOLID IN VARIOUS FORMS WITH CHARACTERISTIC ODOUR. ODOURLESS WHEN DRY.

White, granular or crystalline solid with a faint, almond-like odor.

White, granular or crystalline solid.

White, granular powder or fused pieces

White amorphous lumps or crystalline mass

White cubic crystals

Faint odor of bitter almonds

Odor of hydrogen cyanide.

Faint almond-like odor.

Very high (USCG, 1999)

1173 °F (EPA, 1998)

Not flammable (EPA, 1998)

72 % at 77 °F (NIOSH, 2024)

Sol in 2 parts cold, 1 part boiling water

Sol in 2 parts glycerol

100 g/100 cc hot water above 176 °F

Sol in 25 parts methanol

For more Solubility (Complete) data for POTASSIUM CYANIDE (13 total), please visit the HSDB record page.

Solubility in water, g/l at 25 °C: 716 (freely soluble)

(77 °F): 72%

1.52 at 60.8 °F (EPA, 1998) - Denser than water; will sink

1.55 at 20 °C

1.52 g/cm³

1.55 @ 20°C

0 mmHg (approx) (NIOSH, 2024)

0 mmHg (approx)

In air, it is gradually decomp on exposure to carbon dioxide and moisture.

Not flammable (USCG, 1999)

Potassium ... cyanide solutions give off hydrogen cyanide when heated above 176 °F. /Potassium cyanide soln/

Toxic gases and vapors (such as hydrogen cyanide and carbon monoxide) may be released when cyanide decomposes. /Cyanide/

When heated to decomposition, it emits very toxic fumes of /dipotassium oxide, hydrogen cyanide, and nitrogen oxides/.

11.0 (0.1 N aq soln)

INDEX OF REFRACTION: 1.410

Deliquescent

Approximate Amount of Substance Absorbed by 1 g Charcoal: 35 mg.

Specific heat: 1.01 J/g @ 25-72 °C; heat of fusion: 14.7X10+3 J/mole; heat of formation: -113X10+3 J/mole (exothermic); heat of soln: 11.7X10-3 J/mole; hydrolysis constant: 2.54X10-5 @ 25 °C

Deliquescent. Soluble in water. Dissolution releases some poisonous hydrogen cyanide gas. The amount is not hazardous except in an enclosed space. If the water is acidic, dangerous amounts of hydrogen cyanide form at once.

Based on a scenario where the chemical is spilled into an excess of water (at least 5 fold excess of water), half of the maximum theoretical yield of Hydrogen Cyanide gas will be created in 12 minutes. Experimental details are in the following: "Development of the Table of Initial Isolation and Protective Distances for the 2008 Emergency Response Guidebook", ANL/DIS-09-2, D.F. Brown, H.M. Hartmann, W.A. Freeman, and W.D. Haney, Argonne National Laboratory, Argonne, Illinois, June 2009.

Soluble in water.

Cyanides, Inorganic

Bases, Weak

Water and Aqueous Solutions

Water-Reactive

POTASSIUM CYANIDE is a basic salt and a reducing agent. Reacts with acids of all kinds to generate poisonous hydrogen cyanide gas. Can react violently with oxidizing agents: fusion with metal chlorates, perchlorates, nitrates, or nitrites can cause explosions [Bretherick 1979. p. 101]. A mixture with perchloryl fluoride may explode above 100 °C. A mixture with nitrite salts may cause an explosion [Pieters 1957. p. 30]. Incompatible with iodine. Initiates the explosive decomposition of nitrogen trichloride.

POTASSIUM CYANIDE SOLUTION is weakly basic. Reacts with acids of all kinds to generate quantities of very poisonous hydrogen cyanide gas. Incompatible with strong oxidizing agents, especially if solution dries out. Gives insoluble products with silver(I), mercury(I) and lead(II) ions that may decompose violently under certain conditions.

Reacts with water or any acid releasing hydrogen cyanide.

INCOMPATIBILITIES: ACIDS & ACID SYRUPS, ALKALOIDS, CHLORAL HYDRATE, IODINE, METALLIC SALTS, PERMANGANATES, CHLORATES, PEROXIDES

Chlorates plus potassium cyanide explode when heated.

A mixture of /potassium cyanide and nitrites/ may cause an explosion.

For more Hazardous Reactivities and Incompatibilities (Complete) data for POTASSIUM CYANIDE (14 total), please visit the HSDB record page.

Strong oxidizers (such as acids, acid salts, chlorates & nitrates) [Note: Absorbs moisture from the air forming a syrup.]

IDENTIFICATION: Other cyanides, such as sodium and potassium cyanide, are solid or crystalline hygroscopic salts widely used in ore extracting processes for the recovery of gold and silver, electroplating, case-hardening of steel, base metal flotation, metal degreasing, dyeing, printing, and photography. They are also widely used in the synthesis of organic and inorganic chemicals (e.g., nitriles, carboxylic acids, amides, esters, and amines; heavy metal cyanides) and in the production of chelating agents. HUMAN EXPOSURE: Cyanides are well absorbed via the gastrointestinal tract or skin and rapidly absorbed via the respiratory tract. Once absorbed, cyanide is rapidly and ubiquitously distributed throughout the body, although the highest levels are typically found in the liver, lungs, blood, and brain. There is no accumulation of cyanide in the blood or tissues following chronic or repeated exposure. Approximately 80% of absorbed cyanide is metabolized to thiocyanate in the liver by the mitochondrial sulfur transferase enzyme rhodanese and other sulfur transferases. Thiocyanate is excreted in the urine. Minor pathways for cyanide detoxification involve reaction with cystine to produce aminothiazoline- and iminothiazolidinecarboxylic acids and combination with hydroxycobalamin (vitamin B12a) to form cyanocobalamin (vitamin B12); these end-products are also excreted in the urine. The principal features of the toxicity profile for cyanide are its high acute toxicity by all routes of administration, with a very steep and rate-dependent dose-effect curve, and chronic toxicity, probably mediated through the main metabolite and detoxification product, thiocyanate. The toxic effects of cyanide ion in humans and animals are generally similar and are believed to result from inactivation of cytochrome oxidase and inhibition of cellular respiration and consequent histotoxic anoxia. The primary targets of cyanide toxicity in humans are the cardiovascular, respiratory, and central nervous systems. The endocrine system is also a potential target for long-term toxicity, as a function of continued exposure to thiocyanate, which prevents the uptake of iodine in the thyroid and acts as a goitrogenic agent. Sequele after severe acute intoxications may include neuropsychiatric manifestations and Parkinson-type disease. Cyanide from tobacco smoke has been implicated as a contributing factor in tobacco-alcohol amblyopia. Long-term exposure to lower concentrations of cyanide in occupational settings can result in a variety of symptoms related to central nervous system effects. Cyanides are weakly irritating to the skin and eye; alkali salts have not been identified. ANIMAL/PLANT STUDIES: The principal features of the toxicity profile for cyanide are its high acute toxicity by all routes of administration, with a very steep and rate-dependent dose-effect curve, and chronic toxicity, probably mediated through the main metabolite and detoxification product, thiocyanate. The toxic effects of cyanide ion in humans and animals are generally similar and are believed to result from inactivation of cytochrome oxidase and inhibition of cellular respiration and consequent histotoxic anoxia. The primary targets of cyanide toxicity in animals are the cardiovascular, respiratory, and central nervous systems. The endocrine system is also a potential target for long-term toxicity, as a function of continued exposure to thiocyanate, which prevents the uptake of iodine in the thyroid and acts as a goitrogenic agent. In a 13-week repeated-dose toxicity study in which cyanide was administered in drinking-water, there were no clinical signs associated with central nervous system effects or histopathological effects in the brain or thyroid of rats or mice. There were slight changes in the reproductive tract in male rats, which, although they apparently would not affect fertility in rats. The examination of neurotoxicity in this study was limited to clinical observation and optical microscopy in autopsy. The few available studies specifically intended to investigate neurotoxicity, while reporting adverse effects at exposure levels of 1.2 mg cyanide/kg body weight per day in rats and 0.48 mg cyanide/kg body weight per day in goats, suffer from weaknesses that preclude their quantitative assessment. In relation to characterization of concentration-response for repeated-dose toxicity for inhalation (relevant principally to the occupational environment), in three separate studies in rats, there were no adverse systemic effects in rats exposed to acetone cyanohydrin, which is rapidly hydrolysed to hydrogen cyanide at physiological pH, at concentrations up to 211 mg/m3 (corresponding to a concentration of 67 mg hydrogen cyanide/m3). The steepness of the dose-effect curve is illustrated by the observation of 30% mortality among rats exposed part of the day to 225 mg acetone cyanohydrin/m3 (71 mg hydrogen cyanide/m3). Adverse effects of exposure to the low concentrations of cyanide that are generally present in the general environment (<1 ug/m3 in ambient air; <10 ug/litre in water) are unlikely. /Cyanide/

Organic nitriles decompose into cyanide ions both in vivo and in vitro. Consequently the primary mechanism of toxicity for organic nitriles is their production of toxic cyanide ions or hydrogen cyanide. Cyanide is an inhibitor of cytochrome c oxidase in the fourth complex of the electron transport chain (found in the membrane of the mitochondria of eukaryotic cells). It complexes with the ferric iron atom in this enzyme. The binding of cyanide to this cytochrome prevents transport of electrons from cytochrome c oxidase to oxygen. As a result, the electron transport chain is disrupted and the cell can no longer aerobically produce ATP for energy. Tissues that mainly depend on aerobic respiration, such as the central nervous system and the heart, are particularly affected. Cyanide is also known produce some of its toxic effects by binding to catalase, glutathione peroxidase, methemoglobin, hydroxocobalamin, phosphatase, tyrosinase, ascorbic acid oxidase, xanthine oxidase, succinic dehydrogenase, and Cu/Zn superoxide dismutase. Cyanide binds to the ferric ion of methemoglobin to form inactive cyanmethemoglobin. (L97)

Potassium cyanide

Reproductive

2 x 10 ^-3 mg/kg-day

No indication of carcinogenicity to humans (not listed by IARC).

Exposure to high levels of cyanide for a short time harms the brain and heart and can even cause coma, seizures, apnea, cardiac arrest and death. Chronic inhalation of cyanide causes breathing difficulties, chest pain, vomiting, blood changes, headaches, and enlargement of the thyroid gland. Skin contact with cyanide salts can irritate and produce sores. (L96, L97)

The substance can be absorbed into the body by inhalation, through the skin and by ingestion.

inhalation, skin absorption, ingestion, skin and/or eye contact

Potassium cyanide can affect the body by ingestion, inhalation, skin contact, or eye contact.

Inhalation (L96) ; oral (L96) ; dermal (L96)

Nausea. Dizziness. Drowsiness. Sore throat. Headache. Confusion. Weakness. Shortness of breath. Convulsions. Unconsciousness.

MAY BE ABSORBED! Redness. Pain. Further see Inhalation.

Redness. Pain. Further see Inhalation.

Burning sensation. Nausea. Vomiting. Diarrhoea. See Inhalation.

irritation eyes, skin, upper respiratory system; asphyxia; lassitude (weakness, exhaustion), headache, confusion; nausea, vomiting; increased resp rate, slow gasping respiration; thyroid, blood changes

- Redness, pain, severe burns, and tissue damage (ulceration).

- Contact with the eyes can contribute to whole-body (systemic) toxicity. See Inhalation Exposure.

- Nausea, vomiting (emesis), abdominal pain, and irritation or corrosion of the lining of the esophagus and stomach.

- Whole-body (systemic) toxicity can occur. See Inhalation Exposure.

- Mild to moderate: CNS effects: headache, confusion, anxiety, dizziness, weakness (malaise), and loss of consciousness. Cardiovascular effects: palpitations. Respiratory effects: respiratory tract irritation, difficulty breathing or shortness of breath (dyspnea), and transient increase in the rate and depth of breathing (hyperpnea). GI effects: nausea and vomiting (emesis).

- Severe: CNS effects: coma, seizures, and dilated pupils (mydriasis). Cardiovascular effects: shock, abnormal or disordered heart rhythms (dysrhythmias), critically low blood pressure, and cardiac arrest. Respiratory effects: abnormally rapid, followed by abnormally slow respirations; accumulation of fluid in the lungs (pulmonary edema); and respiratory arrest. Eye effects: dilated pupils, inflammation of the surface of the eye, and temporary blindness.

- Irritation, tissue damage (ulceration), burning sensation, and pain.

- Absorption through the skin can contribute to whole-body (systemic) toxicity. See Inhalation Exposure.

Cyanide poisoning is identified by rapid, deep breathing and shortness of breath, general weakness, giddiness, headaches, vertigo, confusion, convulsions/seizures and eventually loss of consciousness. (L96, L97)

Eyes, skin, respiratory system, cardiovascular system, central nervous system, thyroid, blood

Other Poison - Chemical Asphyxiant

Dermatotoxin - Skin burns.

IRIS Current

HEAST Current

LD50: 5 mg/kg (Oral, Rat) (T14)

LD50: 4 mg/kg (Intraperitoneal, Rat) (T14)

LD50: 9 mg/kg (Subcutaneous, Rat) (T14)

LD50: 2600 ug/kg (Intravenous, Mouse) (T14)

LD50 Rat oral 5 mg/kg

LD50 Rat ip 4 mg/kg

LD50 Rat sc 9 mg/kg

LD50 Rat iv 3600 mg/kg

For more Non-Human Toxicity Values (Complete) data for POTASSIUM CYANIDE (16 total), please visit the HSDB record page.

Antidotes to cyanide poisoning include hydroxocobalamin and sodium nitrite, which release the cyanide from the cytochrome system, and rhodanase, which is an enzyme occurring naturally in mammals that combines serum cyanide with thiosulfate, producing comparatively harmless thiocyanate. Oxygen therapy can also be administered. (L97)

CHLORPROMAZINE ANTAGONISM OF CYANIDE INTOXICATION WAS POTENTIATED BY SODIUM THIOSULFATE. CHLORPROMAZINE & SODIUM NITRITE DID NOT PROTECT AGAINST KCN LETHALITY BETTER THAN NITRITE ALONE.

To elucidate the interaction of carbon monoxide (CO) and cyanide, the fluorescence which represents the intracellular reduced pyridine nucleotide was measured on the rabbit kidney surface in situ. Various doses of potassium cyanide, 2-8 umol/kg, were administered intravenously with and without inhalation of 1, 2 and 3% carbon monoxide via a respirator. The dose-response relationship between potassium cyanide and the fluorescence increase fitted a salient sigmoid curve with a steep slope, and carbon monoxide was potent to increase fluorescence independently and shifted the dose response curve for potassium cyanide to the left. The combined effect of carbon monoxide and potassium cyanide was of a critical dose for intracellular respiration, it had the appearance of synergism.

Previous reports indicated that prophylactic protection against cyanide intoxication in mice can be enhanced by administration of chlorpromazine when it is given with sodium thiosulfate. The mechanism of potentiation of sodium thiosulfate by chlorpromazine was studied alone and in combination with sodium nitrite. Although chlorpromazine was found to induce a hypothermic response, the mechanism of enhancement of the antagonism of cyanide by chlorpromazine does not correlate with the hypothermia produced. Various other possible mechanisms were investigated, such as rate of methemoglobin formation, enzymatic activity of rhodanese and cytochrome oxidase, and alpha-adrenergic blockade. The alpha-adrenergic blocking properties of chlorpromazine may provide a basis for its antidotal effect, since this protective effect can be reversed with an alpha-antagonist, methoxamine. /Cyanide/

1.60e+02

2.30e+03

9.40e+00

3.90e+01

4.00e+01

2.00e+02

2.00e-03

9.00e-03

Volatile

4.70e+02

7.00e+03

2.80e+01

1.20e+02

The substance is very toxic to aquatic organisms.

In bacteria, cyanide production has been observed in Chromobacterium violaceum and certain species of Pseudomonas. /Cyanide/

Material containing cyanide compounds disposed of on land may lead to elevated levels of cyanide in underlying strata and in groundwater. /Cyanides/

Aquatic Fate: The alkali metal salts are very soluble in water, and as a result, they readily dissociate into their respective anions and cations upon release to water. The resulting cyanide ion may then form hydrogen cyanide or react with various metals present in natural water. If the cyanide ion is present in excess, complex metallocyanides may form; however, if metals are prevalent, simple metal cyanides may form. /Alkali metal cyanides/

Poisoning may occur by ingestion, absorption through injured skin or inhalation of hydrogen cyanide, liberated by action of carbon dioxide or other acids.

... SYMPTOMS OF CHRONIC DISEASE ... REPORTED IN ELECTROPLATERS & SILVER POLISHERS AFTER SEVERAL YEARS OF EXPOSURE. /CYANIDES/

AMONG FUMIGATORS ... CYANIDE POISONING IS RECOGNIZED ... /CYANIDES/

DERMATITIS ... IN WORKERS CHRONICALLY EXPOSED TO CYANIDE SOLN. ELECTROPLATERS SUFFER FROM SUCH IRRITATION. /CYANIDE SOLN/

Cyanide is present in normal healthy human organs at concentrations ranging up to 0.5 mg/kg. /Cyanide/

Generators of waste (equal to or greater than 100 kg/mo) containing this contaminant, EPA hazardous waste number P098; D003, must conform with USEPA regulations in storage, transportation, treatment and disposal of waste.

Cyanide salts should not be flushed into any drain which may contain or subsequently receive acid waste. ... Cyanide process waste solutions and flushings from spills should be passed through a cyanide waste disposal system. /Cyanide salts/

Potassium cyanide is a poor candidate for incineration.

If ... THERE IS NO FIRE, go directly to the Table of Initial Isolation and Protective Action Distances /(see table below)/ ... to obtain initial isolation and protective action distances. IF THERE IS A FIRE, or IF A FIRE IS INVOLVED, go directly to the appropriate guide /(see guide(s) below)/ and use the evacuation information shown under PUBLIC SAFETY. /Potassium cyanide; Potassium cyanide, solid/

Table: Table of Initial Isolation and Protective Action Distances for Potassium cyanide; Potassium cyanide, solid (when spilled in water) [Table#3051]

Table of Water-Reactive Materials Which Produce Toxic Gases

Table: Materials Which Produce Large Amounts of Toxic-by-Inhalation Gas(es) When Spilled in Water [Table#3052]

/GUIDE 157: SUBSTANCES - TOXIC AND/OR CORROSIVE (NON-COMBUSTIBLE/WATER -SENSITIVE)/ Health: TOXIC; inhalation, ingestion or contact (skin, eyes) with vapors, dusts or substance may cause severe injury, burns, or death. Reaction with water or moist air will release toxic, corrosive or flammable gases. Reaction with water may generate much heat which will increase the concentration of fumes in the air. Fire will produce irritating, corrosive and/or toxic gases. Runoff from fire control or dilution water may be corrosive and/or toxic and cause pollution. /Potassium cyanide; Potassium cyanide, solid; Potassium cyanide, solution/

/GUIDE 157: SUBSTANCES - TOXIC AND/OR CORROSIVE (NON-COMBUSTIBLE/WATER -SENSITIVE)/ Fire or Explosion: Non-combustible, substance itself does not burn but may decompose upon heating to produce corrosive and/or toxic fumes. Vapors may accumulate in confined areas (basement, tanks, hopper/tank cars etc.). Substance will react with water (some violently), releasing corrosive and/or toxic gases. Contact with metals may evolve flammable hydrogen gas. Containers may explode when heated or contaminated with water. /Potassium cyanide; Potassium cyanide, solid; Potassium cyanide, solution/

For more DOT Emergency Guidelines (Complete) data for POTASSIUM CYANIDE (10 total), please visit the HSDB record page.

1680 157(solid)

3413 157(solution)

UN 1680; Potassium cyanide soln; potassium cyanide, solid

IMO 6.1; Potsssium cyanide

49 232 26; Potassium cyanide, solid

49 232 25; Potassium cyanide, solution

No person may /transport,/ offer or accept a hazardous material for transportation in commerce unless that person is registered in conformance ... and the hazardous material is properly classed, described, packaged, marked, labeled, and in condition for shipment as required or authorized by ... /the hazardous materials regulations (49 CFR 171-177)./

The International Air Transport Association (IATA) Dangerous Goods Regulations are published by the IATA Dangerous Goods Board pursuant to IATA Resolutions 618 and 619 and constitute a manual of industry carrier regulations to be followed by all IATA Member airlines when transporting hazardous materials.

The International Maritime Dangerous Goods Code lays down basic principles for transporting hazardous chemicals. Detailed recommendations for individual substances and a number of recommendations for good practice are included in the classes dealing with such substances. A general index of technical names has also been compiled. This index should always be consulted when attempting to locate the appropriate procedures to be used when shipping any substance or article.

Airtight. Unbreakable packaging. Put breakable packaging into closed unbreakable container. Do not transport with food and feedstuffs. Marine pollutant.

UN Hazard Class: 6.1; UN Pack Group: I