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HYDROGEN CYANIDE, LIQUEFIED ICSC: 0492
Date of Peer Review: May 2003

Hydrocyanic acid
Prussic acid
Formonitrile
(liquefied)
CAS # 74-90-8 HCN
RTECS # MW6825000 Molecular mass: 27.03
UN # 1051
EC # 006-006-00-X
TYPES OF HAZARD / EXPOSURE ACUTE HAZARDS / SYMPTOMS PREVENTION FIRST AID / FIRE FIGHTING
FIRE Extremely flammable. Gives off irritating or toxic fumes (or gases) in a fire.
NO open flames, NO sparks, and NO smoking.
Shut off supply; if not possible and no risk to surroundings, let the fire burn itself out; in other cases extinguish with powder, water spray, foam, carbon dioxide.
EXPLOSION Gas/air mixtures are explosive.
Closed system, ventilation, explosion-proof electrical equipment and lighting.
In case of fire: keep cylinder cool by spraying with water. Combat fire from a sheltered position.
EXPOSURE
AVOID ALL CONTACT!
IN ALL CASES CONSULT A DOCTOR!
Inhalation Confusion. Drowsiness. Headache. Nausea. Convulsions. Shortness of breath. Unconsciousness. Death.
Ventilation, local exhaust, or breathing protection.
Fresh air, rest. Half-upright position. No mouth-to-mouth artificial respiration. Administer oxygen by trained personnel. Refer for medical attention. See Notes.
Skin MAY BE ABSORBED! (Further see Inhalation).
Protective gloves. Protective clothing.
Rinse skin with plenty of water or shower. Refer for medical attention. Wear protective gloves when administering first aid.
Eyes VAPOUR WILL BE ABSORBED! Redness. (See Inhalation).
Safety goggles, or eye protection in combination with breathing protection.
First rinse with plenty of water for several minutes (remove contact lenses if easily possible), then take to a doctor.
Ingestion Burning sensation. (Further see Inhalation).
Do not eat, drink, or smoke during work. Wash hands before eating.
Rinse mouth. Do NOT induce vomiting. No mouth-to-mouth artificial respiration. Administer oxygen by trained personnel. Refer for medical attention. See Notes.
SPILLAGE DISPOSAL PACKAGING & LABELLING
Evacuate danger area immediately! Consult an expert! Ventilation. Remove all ignition sources. Absorb remaining liquid in sand or inert absorbent and remove to safe place. NEVER direct water jet on liquid. Do NOT let this chemical enter the environment. Gas-tight chemical protection suit including self-contained breathing apparatus.
Marine pollutant.
EU Classification
Symbol: F+, T+, N
R: 12-26-50/53
S: (1/2-)-7/9-16-36/37-38-45-60-61
UN Classification
UN Hazard Class: 6.1
UN Subsidiary Risks: 3
UN Pack Group: I
EMERGENCY RESPONSE STORAGE
Transport Emergency Card: TEC (R)-61S1051
NFPA Code: H4; F4; R2;
Fireproof. Separated from food and feedstuffs. Cool. Store only if stabilized.
IPCS
International
Programme on
Chemical Safety
Prepared in the context of cooperation between the International Programme on Chemical Safety and the Commission of the European Communities IPCS, CEC 1999

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HYDROGEN CYANIDE, LIQUEFIED ICSC: 0492
IMPORTANT DATA
PHYSICAL STATE; APPEARANCE:
COLOURLESS GAS OR LIQUID, WITH CHARACTERISTIC ODOUR.

PHYSICAL DANGERS:
The gas mixes well with air, explosive mixtures are easily formed.

CHEMICAL DANGERS:
The substance may polymerize due to heating under the influence of base(s), over 2% water, or if not chemically stabilized, with fire or explosion hazard. On combustion, forms toxic and corrosive gases including nitrogen oxides. The solution in water is a weak acid. Reacts violently with oxidants, hydrogen chloride in alcoholic mixtures, causing fire and explosion hazard.

OCCUPATIONAL EXPOSURE LIMITS:
TLV: 4.7 ppm; (Ceiling value); (skin); (ACGIH 2003).
MAK: 1.9 ppm, 2.1 mg/m; H; Peak limitation category: II(2); Pregnancy risk group: C; (DFG 2002).
ROUTES OF EXPOSURE:
The substance can be absorbed into the body by inhalation, through the skin and by ingestion.

INHALATION RISK:
A harmful contamination of the air will be reached very quickly on evaporation of this substance at 20C.

EFFECTS OF SHORT-TERM EXPOSURE:
The substance is irritating to the eyes and the respiratory tract. The substance may cause effects on the cellular respiration, resulting in convulsions and unconsciousness. Exposure may result in death. Medical observation is indicated. See Notes.

EFFECTS OF LONG-TERM OR REPEATED EXPOSURE:
The substance may have effects on the thyroid.
PHYSICAL PROPERTIES
Boiling point: 26C
Melting point: -13C
Relative density (water = 1): 0.69 (liquid)
Solubility in water: miscible
Vapour pressure, kPa at 20C: 82.6
Relative vapour density (air = 1): 0.94
Flash point: -18C c.c.
Auto-ignition temperature: 538C
Explosive limits, vol% in air: 5.6-40.0
Octanol/water partition coefficient as log Pow: -0.25
ENVIRONMENTAL DATA
The substance is very toxic to aquatic organisms.
NOTES
The occupational exposure limit value should not be exceeded during any part of the working exposure. Specific treatment is necessary in case of poisoning with this substance; the appropriate means with instructions must be available. The odour warning when the exposure limit value is exceeded is insufficient. The recommendations on this Card also apply to hydrogen cyanide, stabilized, absorbed in a porous inert material. Other UN numbers: 1613, Hydrogen cyanide, aqueous solution, not more than 20% of hydrogen cyanide; 1614, Hydrogen cyanide stabilized, absorbed in a porous inert material; 3294, Hydrogen cyanide solution in alcohol, not more than 45% of hydrogen cyanide. Never work alone in an area if hydrogen cyanide exposure is possible. Depending on the degree of exposure, periodic medical examination is suggested.
ADDITIONAL INFORMATION


LEGAL NOTICE Neither the CEC nor the IPCS nor any person acting on behalf of the CEC or the IPCS is responsible for the use which might be made of this information
IPCS, CEC 1999
See Also:
        Hydrogen canide (PIM 693)
        Hydrogen cyanide (CHEMINFO)