UN 2478 — Isocyanates, flammable, toxic, n.o.s.
Placard: Flammable. ERG Guide 155. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 2478 At a Glance
UN 2478 (Isocyanates, flammable, toxic) is listed as DOT Class 3 Flammable and is assigned to ERG Guide 155. Use this page to review placard data, common hazards, PPE notes, isolation context, first actions, and related UN numbers.
UN 2478 is Isocyanates, flammable, toxic, n.o.s., 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 2478, 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 2478 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: Isocyanates, flammable, toxic, n.o.s. 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: Isocyanates, flammable, toxic, n.o.s. 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 2478 Quick Details
Common Hazards of UN 2478
- 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
Typically colorless to pale yellow liquids with pungent, acrid odor. Physical state varies by specific isocyanate compound; most are liquids at room temperature.
| Also known as | Isocyanate compoundsOrganic isocyanatesFlammable isocyanatesToxic isocyanatesIsocyanate mixtures |
| Appearance | Typically colorless to pale yellow liquids with pungent, acrid odor. Physical state varies by specific isocyanate compound; most are liquids at room temperature. |
| Flash Point | Below 23°C (73°F) - flammable liquid |
| Boiling Point | Varies by compound, typically 100-200°C (212-392°F) |
| Vapor Density | Heavier than air (typically 2-6 times air density) |
| Water Reactivity | Reacts with water, generating heat and carbon dioxide. May form polyurea and release toxic fumes. Avoid water contact. |
Fireground Response Guidance — UN 2478
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 2478 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 2478 — Isocyanates, flammable, toxic, n.o.s.Use 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.