UN 2357 — Cyclohexylamine
Placard: Corrosive. ERG Guide 132. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 2357 is Cyclohexylamine, a flammable corrosive amine assigned to ERG Guide 132. Vapor flashback, alkaline burns and toxic/corrosive runoff are key concerns.
Hazard overview: FLAMMABLE and CORROSIVE amine liquid; vapors may ignite and form explosive mixtures with air. Liquid and vapor can burn eyes, skin and respiratory tissue. Vapors are heavier than air and may travel to ignition sources and flash back.
Response guidance: For UN 2357, isolate the area, eliminate ignition sources and use SCBA. Prevent vapor entry into drains, contain alkaline/toxic runoff and select foam, dry chemical or CO2 based on SDS and ERG 132.
Firefighter training notes: Training for UN 2357 should emphasize amine/nitrile exposure, corrosive or toxic runoff, SCBA use, sewer flashback, decontamination, foam selection and container cooling. Use ERG 132, SDS and local SOP.
Regulatory context: Cyclohexylamine is regulated as a hazardous material for transport and emergency response. Storage, exposure, spill reporting, waste and fire-code duties depend on quantity, concentration and jurisdiction; verify shipping papers, SDS and local authority requirements.
Storage & handling: Cyclohexylamine should be stored in approved flammable/corrosive-liquid containers with ventilation, secondary containment and separation from heat, ignition sources, acids, oxidizers and incompatible materials.
UN 2357 Quick Details
Common Hazards of UN 2357
- FLAMMABLE and CORROSIVE amine liquid; vapors may ignite and form explosive mixtures with air.
- Liquid and vapor can burn eyes, skin and respiratory tissue.
- Vapors are heavier than air and may travel to ignition sources and flash back.
- Mixing with water may generate heat and spread alkaline/corrosive contamination.
- Runoff to sewers may create fire, explosion and corrosive contamination hazards.
- Fire may produce nitrogen oxides and irritating/toxic smoke.
- Containers may rupture or explode when heated.
Chemical Identity & Physical Properties
Colorless to yellow liquid with a strong, fishy ammonia-like odor. Fuming in air.
| Also known as | AminocyclohexaneCyclohexanamineHexahydroanilineCHA |
| CAS Number | 108-91-8 |
| Appearance | Colorless to yellow liquid with a strong, fishy ammonia-like odor. Fuming in air. |
| Flash Point | 31C (88F) |
| Boiling Point | 134C (273F) |
| Vapor Density | 3.42 (heavier than air) |
| Water Reactivity | Soluble in water with moderate heat generation; forms caustic alkaline solution |
Fireground Response Guidance — UN 2357
Extinguishing Media
PPE Requirements
Use positive-pressure SCBA for vapor, fire or confined-space exposure. Wear chemical-resistant gloves, boots, eye/face protection and protective clothing; avoid skin contact.
Isolation & Evacuation
First Actions for a UN 2357 Incident
- Call 911 and the emergency response number on the shipping paper, if available.
- Keep unauthorized personnel away and establish incident command.
- Stay upwind, uphill and upstream; keep responders out of low vapor areas.
- Eliminate ignition sources if this can be done safely.
- Avoid breathing vapor, mist or smoke and avoid skin or eye contact.
- Prevent alkaline, toxic or corrosive runoff from entering drains and waterways.
- Do not touch damaged containers or spilled material without proper training and PPE.
- Ventilate confined spaces only after monitoring and only if properly trained and equipped.
- Use ERG Guide 132, SDS, shipping papers and air monitoring to set isolation, evacuation and entry decisions.
📋 Copy & Share Field Card
UN 2357 — CyclohexylamineUse 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.