Educational content for trained professionals. Not a Safety Data Sheet, not medical advice. In an emergency, call your local poison control or emergency services immediately. Terms of use.
Hydrogen Cyanide
Also known as: hydrogen cyanide · hydrocyanic acid · Formonitrile · Prussic acid
- CAS No.
- 74-90-8
- Formula
- CHN
- Molar mass
- 27.025 g/mol
- PubChem CID
- 768
Flammable
Toxic
Harmful / Irritant
Health hazard
Environmental hazard
Summary
Hydrogen Cyanide (CHN), CAS 74-90-8. Common in labs and industry. Read on for hazards, storage, PPE and mixing rules.
Background
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Hazards
Ignites easily when exposed to a flame or spark.
May be fatal even in small doses.
May cause skin, eye or respiratory irritation.
Serious long-term health effects (CMR, respiratory sensitizer).
Toxic to aquatic organisms.
Hazard statements
- H224: Extremely flammable liquid and vapor [Danger Flammable liquids]
- H330: Fatal if inhaled [Danger Acute toxicity, inhalation]
- H400: Very toxic to aquatic life [Warning Hazardous to the aquatic environment, acute hazard]
- H410: Very toxic to aquatic life with long lasting effects [Warning Hazardous to the aquatic environment, long-term hazard]
- H300: Fatal if swallowed [Danger Acute toxicity, oral]
- H310: Fatal in contact with skin [Danger Acute toxicity, dermal]
- H372: Causes damage to organs through prolonged or repeated exposure [Danger Specific target organ toxicity, repeated exposure]
- H319: Causes serious eye irritation [Warning Serious eye damage/eye irritation]
- H370: Causes damage to organs [Danger Specific target organ toxicity, single exposure]
Storage
Keep at room temperature, below 30 °C, out of direct heat.
Store somewhere well-ventilated and away from any ignition source.
Metal drums or tinted glass, tightly sealed.
Strong acids, strong bases and powerful oxidizers.
Personal protective equipment
Nitrile or butyl, at least 0.4 mm thick.
Safety goggles with side shields.
A2 organic-vapor cartridge if the room isn't well ventilated.
Occupational exposure limits (HSE)
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EU harmonised classification (ECHA C&L)
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Transport
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FDA recalls & enforcement
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Compatibilities
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Open comparator with Hydrogen CyanidePractical safety notes
- Flammable. Keep away from open flames, hot surfaces and sparks. Ground containers when transferring.
- Acute toxicity. Work under a fume hood, restrict access, keep a specific antidote plan available.
- Irritant / harmful. Ventilate the workspace and avoid skin contact.
- Serious health hazard (carcinogen, mutagen, reprotoxic, respiratory sensitizer). Substitute if possible; otherwise closed systems and medical surveillance.
- Environmental hazard. Do not release to sewers or waterways; collect for hazardous waste disposal.
Derived from the GHS classification shown above. These notes are generic guidance and do not replace the manufacturer's SDS or your local risk assessment.
FAQ
Is Hydrogen Cyanide flammable?+
Yes. Hydrogen Cyanide (CAS 74-90-8) carries the GHS02 flame pictogram. Keep it away from ignition sources, use non-sparking tools, and ground metal containers when transferring liquid.
What PPE should I wear when handling Hydrogen Cyanide?+
Safety glasses with side shields and nitrile gloves are the baseline. Work inside a fume hood or use a suitable respirator. Check SDS section 8 for material-specific breakthrough times.
How should Hydrogen Cyanide be stored?+
Store Hydrogen Cyanide (CAS 74-90-8) in tightly closed original containers, in a cool, dry, well-ventilated area away from incompatible materials. Use a flammable-liquid cabinet and keep away from oxidizers and heat.
Is Hydrogen Cyanide dangerous for the environment?+
Yes. Hydrogen Cyanide carries the GHS09 environment pictogram. Do not release to drains, soil or waterways; collect residues for hazardous-waste disposal in line with local regulations.
Where can I find the official Safety Data Sheet for Hydrogen Cyanide?+
Official, up-to-date SDS documents are published by each manufacturer (Sigma-Aldrich, Merck, Thermo Fisher, VWR, Carl Roth, etc.) and by regulators such as ECHA and NIOSH. This page is an educational summary and does not replace the manufacturer's SDS.
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