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Name: Hydrocyanic Acid
Chemical Formula: HCN
Common Uses: Pest control in enclosed structures, fumigation for stored products
Appearance: Clear, colorless to pale blue liquid that emits a bitter almond odor
Odor Threshold: Often undetectable to those with a genetic insensitivity to cyanide’s smell
Synonyms: Prussic acid, Cyanohydric acid
Molecular Weight: 27.03 g/mol
Hazard Classification: Acute Toxicity, Oral, Inhalation and Dermal; Flammable liquid and vapor; Environmental Hazard
Signal Word: Danger
Major Hazards: Extremely toxic by inhalation, ingestion, and skin contact; Fire and explosion hazard due to low flash point; Rapid acting poison affecting cellular respiration
Symptoms: Headache, dizziness, shortness of breath, confusion, convulsions, respiratory failure
Routes of Exposure: Inhalation, skin absorption, ingestion
Active Compound: Hydrocyanic Acid (HCN), usually above 95% concentration in fumigant formulations
Impurities: Water, stabilizers to prevent polymerization, minor trace of acids
Inhalation: Move person to fresh air immediately, keep still, give oxygen if possible, seek urgent medical attention
Skin Contact: Remove all contaminated clothing, rinse skin thoroughly with soap and water
Eye Contact: Rinse eyes slowly and gently with plenty of water, prioritize immediate transfer to hospital
Ingestion: Do not induce vomiting, immediate medical care essential, administer oxygen and specific antidotes if available
Antidotes: Hydroxocobalamin and sodium thiosulfate are mainstay treatments in clinical settings
Suitable Extinguishing Media: Dry chemical, carbon dioxide, alcohol-resistant foam
Unsuitable Media: Avoid using water jets, as they can spread the chemical
Hazards: Vapors can form explosive mixtures with air; containers may explode in fire; hydrocyanic acid produces highly toxic gases including hydrogen cyanide on combustion
Protective Equipment: Use self-contained breathing apparatus and full protective suit
Further Precautions: Approach from upwind, isolate area, evacuate non-essential personnel
Personal Protection: Evacuate area, ventilate, don self-contained breathing apparatus, wear chemical-resistant clothing
Containment: Eliminate all ignition sources, use non-sparking tools
Cleanup: Absorb with inert material (e.g., clay, sand), collect in chemical waste container with tight seal
Decontamination: Apply dilute alkali for neutralization if safe
Avoid: Contact with acid and metallic salts, entry into water systems or drains
Handling Precautions: Only trained and properly equipped personnel should handle; verify ventilation in all areas; minimize vapor release; keep away from incompatible materials
Storage: Store in cool, dry, well-ventilated, secured and approved container; keep container closed when not in use; segregate from oxidizers, acids, and metals
Fire Prevention: Maintain low temperature to slow vaporization; avoid direct sunlight and sources of heat
Exposure Limits: OSHA Ceiling 10 ppm; NIOSH IDLH 50 ppm
Engineering Controls: Exhaust ventilation, continuous air monitoring, gas detectors for cyanide
Personal Protective Equipment: Full body chemical resistant suit, gloves, boots, self-contained breathing apparatus
Hygiene Measures: Prohibit food or drink in work area; wash thoroughly after handling; strict procedures for decontamination
Appearance: Colorless to pale blue volatile liquid
Odor: Bitter almond, not detectable to all
Boiling Point: About 25.6°C (78°F)
Melting Point: -13.4°C (7.9°F)
Flash Point: -17.8°C (0°F)
Solubility: Miscible with water, ethanol, ether
Vapor Density: Heavier than air
Vapor Pressure: High volatility leads to rapid vapor formation
Chemical Stability: Unstable; stabilizers required
Reactivity: Reacts vigorously with oxidizers, alkalis, acids
Conditions to Avoid: Heat, light, pressure shocks
Incompatible Materials: Acids, alkaline metals, strong oxidizing agents
Hazardous Decomposition: Hydrogen cyanide, nitrogen oxides, ammonia
Acute Toxicity: Rapidly acting systemic poison via inhalation, skin, ingestion; LC50 (human estimated) less than 100 ppm for 1 hour
Target Organs: Central nervous system, cardiovascular system, respiratory system
Symptoms of Overexposure: Seizures, confusion, cardiac arrest, breathing difficulty, unconsciousness, death
Chronic Exposure: Recurrent low doses may cause weakness, nerve damage, thyroid disorders
Aquatic Toxicity: Highly toxic to fish and aquatic organisms; rapid degradation in environment, but acute impacts on exposed biota
Persistence: Short half-life in air and water due to volatility and degradation, yet spills cause acute ecological crises
Bioaccumulation: Not significant, but immediate effects on local ecosystems can be devastating
Safe Disposal: Must be neutralized chemically before destruction; incinerate only in facilities licensed for cyanide compounds
Do Not: Flush into drains or natural water sources; avoid open-air evaporation or uncontrolled release
Waste Handling: Contaminated materials treated as hazardous; store and transport tightly closed, labeled, and secure until final disposal
UN Number: 1613
Class: 6.1 (Poisonous substances, Toxic by inhalation)
Transport Precautions: Use only dedicated, approved vehicles; maintain proper ventilation; emergency response protocols required
Packing Group: I (indicates great danger)
Shipping Name: Hydrogen cyanide, stabilized
Additional Notes: Strict regulatory requirements for documentation, signage, and driver training apply
Workplace Control: Maximum exposure limits enforced by OSHA, NIOSH, and ACGIH
Chemical Inventory: Listed as a toxic substance under numerous national and international statutes
Health and Safety: Classified as Highly Hazardous Chemical; controlled under Poison Control Acts, SARA Title III, and REACH
Environmental Regulations: Controlled for direct discharge, manufacture, and use under EPA, EC, and local authorities
PPE and Training: Governmental standards mandate robust training and documented protective equipment for all personnel
