UN 2224 — Benzonitrile
Placard: Toxic. ERG Guide 152. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 2224 is Benzonitrile, a highly toxic nitrile liquid assigned to ERG Guide 152. Skin absorption and toxic fire products require strict exposure control.
Hazard overview: HIGHLY TOXIC nitrile liquid; may be harmful or fatal if inhaled, ingested or absorbed through skin. Combustible material: may burn but does not ignite readily. Skin absorption and contaminated clothing are major exposure concerns.
Response guidance: For a UN 2224 incident, verify the product with shipping papers, container markings, SDS and ERG Guide 152. Establish incident command, isolate the area, stay upwind, control ignition or incompatibility hazards, prevent runoff, dust or vapor spread and base entry/fire-control actions on monitoring and local SOP.
Firefighter training notes: Training for UN 2224 should emphasize toxic skin/dust/vapor exposure, contaminated clothing, toxic fire products, decontamination waste and runoff containment. Use ERG 152, SDS and local SOP.
Regulatory context: Benzonitrile is regulated as a hazardous material for transportation and emergency response purposes. Storage, workplace exposure, emergency planning, spill reporting, waste handling and environmental requirements vary by exact product, concentration, quantity and jurisdiction. Verify current requirements through shipping papers, SDS, container markings and applicable DOT, OSHA, EPA, NFPA, state or local authority guidance.
Storage & handling: Benzonitrile should be stored in tightly closed compatible containers in a secure toxic-material area with secondary containment, restricted access, ventilation and waste/decontamination planning according to SDS.
UN 2224 Quick Details
Common Hazards of UN 2224
- HIGHLY TOXIC nitrile liquid; may be harmful or fatal if inhaled, ingested or absorbed through skin.
- Combustible material: may burn but does not ignite readily.
- Skin absorption and contaminated clothing are major exposure concerns.
- Fire may produce hydrogen cyanide, nitrogen oxides and other toxic gases.
- Runoff may carry toxic nitrile contamination.
- Vapors may collect in low or poorly ventilated areas when heated.
- Containers may rupture or fail when heated.
Chemical Identity & Physical Properties
Colorless to pale yellow oily liquid with a distinct almond-like odor. Liquid at room temperature with moderate viscosity.
| Also known as | Phenyl cyanideCyanobenzeneBenzenecarbonitrilePhenylnitrile |
| CAS Number | 100-47-0 |
| Appearance | Colorless to pale yellow oily liquid with a distinct almond-like odor. Liquid at room temperature with moderate viscosity. |
| Flash Point | 71°C (160°F) |
| Boiling Point | 191°C (376°F) |
| Vapor Density | 3.6 (heavier than air) |
| Water Reactivity | No significant reaction with water; slightly soluble |
Fireground Response Guidance — UN 2224
Extinguishing Media
PPE Requirements
Use positive-pressure SCBA for dust, vapor, mist, fire or confined-space exposure. Wear chemical-resistant gloves, boots, eye/face protection and protective clothing selected from SDS; avoid all skin contact.
Isolation & Evacuation
First Actions for a UN 2224 Incident
- CALL 911. Then call the emergency response telephone number on the shipping paper, if available.
- Keep unauthorized personnel away.
- Stay upwind, uphill and/or upstream.
- Avoid breathing vapors, dust, mist, smoke or fumes and avoid skin or eye contact.
- Do not touch damaged containers or spilled material unless properly trained and wearing appropriate protective equipment.
- Prevent contaminated dust, liquid, residues, runoff and decontamination waste from spreading.
- Ventilate closed spaces before entering, but only if properly trained, equipped, monitored and authorized by incident command.
- Isolate the spill or release area and expand the perimeter for fire involvement, vapor spread, dust generation, water reaction or unknown product identity.
- Use ERG Guide 152, shipping papers, SDS, air monitoring and incident command for protective actions.
📋 Copy & Share Field Card
UN 2224 — BenzonitrileUse for: Quick radio or face-to-face size-up. Short, structured, field-ready.
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief.
Use for: Quick text to command or incoming units. Fits in a single SMS.