UN 2484 — tert-Butyl isocyanate
Placard: Toxic. ERG Guide 155. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 2484 is tert-Butyl isocyanate, an isocyanate entry assigned to ERG Guide 155. Respiratory sensitization, water reaction and toxic vapor control are key concerns.
Hazard overview: TOXIC isocyanate liquid; inhalation of vapor or aerosol may cause severe respiratory sensitization and injury. Flammable or combustible liquid; vapors may form explosive mixtures with air depending on the exact material. Vapors are heavier than air and may travel to ignition sources and flash back.
Response guidance: For UN 2484, isolate the area, eliminate ignition sources where relevant and use SCBA. Avoid direct water on liquid, control vapor/aerosol exposure and contain isocyanate runoff under ERG 155.
Firefighter training notes: Training for UN 2484 should emphasize isocyanate respiratory sensitization, water reaction/CO2 pressure, vapor monitoring, PPE, decontamination and runoff containment. Use ERG 155, SDS and local SOP.
Regulatory context: tert-Butyl isocyanate 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: tert-Butyl isocyanate should be stored in tightly closed compatible containers in a cool, dry, ventilated area away from water/moisture, amines, alcohols, acids/bases where incompatible and heat.
UN 2484 Quick Details
Common Hazards of UN 2484
- TOXIC isocyanate liquid; inhalation of vapor or aerosol may cause severe respiratory sensitization and injury.
- Flammable or combustible liquid; vapors may form explosive mixtures with air depending on the exact material.
- Vapors are heavier than air and may travel to ignition sources and flash back.
- Reacts with water to release carbon dioxide, heat and polymeric solids; pressure buildup may occur in closed containers.
- Skin and eye contact may cause irritation, burns or sensitization.
- Fire may produce nitrogen oxides, isocyanate vapors, hydrogen cyanide-type products and other toxic gases.
- Runoff may spread toxic isocyanate contamination.
Chemical Identity & Physical Properties
Colorless to pale yellow liquid with a pungent, sharp odor. Volatile liquid at room temperature.
| Also known as | tert-Butylisocyanatet-Butyl isocyanate2-Methylpropyl isocyanateTrimethylmethyl isocyanate1,1-Dimethylethyl isocyanate |
| CAS Number | 1609-86-5 |
| Appearance | Colorless to pale yellow liquid with a pungent, sharp odor. Volatile liquid at room temperature. |
| Flash Point | -7C (19F) |
| Boiling Point | 85-87C (185-189F) |
| Vapor Density | 3.4 (heavier than air) |
| Water Reactivity | Reacts with water liberating carbon dioxide gas and forming amines; reaction generates heat |
Fireground Response Guidance — UN 2484
Extinguishing Media
PPE Requirements
Use positive-pressure SCBA for vapor, aerosol, fire or confined-space exposure. Wear chemical-resistant gloves, boots, eye/face protection and protective clothing; Level A may be needed for heavy vapor.
Isolation & Evacuation
First Actions for a UN 2484 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.
- Avoid breathing vapor, dust, mist, smoke or fumes and avoid skin or eye contact.
- Avoid unnecessary water contact with released product because heat, gas or pressure buildup may occur.
- 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 155, SDS, shipping papers and monitoring to set isolation, evacuation and entry decisions.
📋 Copy & Share Field Card
UN 2484 — tert-Butyl isocyanateUse 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.