UN 2304 — Naphthalene, molten
Placard: Flammable Solid. ERG Guide 133. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 2304 is Naphthalene, molten, a combustible molten organic material assigned to ERG Guide 133. Molten contact can cause severe burns and heated vapors can ignite.
Hazard overview: COMBUSTIBLE molten organic material; may burn and produce dense irritating smoke. Molten material can cause severe thermal burns and may cling to skin or PPE. Vapors may form ignitable mixtures with air when heated above normal handling temperatures.
Response guidance: For a UN 2304 incident, verify the product with shipping papers, container markings, SDS and ERG Guide 133. 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 2304 should emphasize exposure routes, air monitoring, PPE selection, fire behavior, decontamination, runoff containment and ERG/SDS verification. Use ERG 133, SDS and local SOP.
Regulatory context: Naphthalene, molten 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: Naphthalene, molten should be stored in compatible heated containers or solid storage according to SDS, away from ignition sources, oxidizers and drains. Provide spill containment for molten material.
UN 2304 Quick Details
Common Hazards of UN 2304
- COMBUSTIBLE molten organic material; may burn and produce dense irritating smoke.
- Molten material can cause severe thermal burns and may cling to skin or PPE.
- Vapors may form ignitable mixtures with air when heated above normal handling temperatures.
- Solidified residues can continue to off-gas odor and contamination.
- Fire may produce carbon monoxide, soot and irritating/toxic aromatic smoke.
- Runoff may carry hydrocarbon contamination and harm waterways.
- Containers may rupture or fail when heated.
Chemical Identity & Physical Properties
White crystalline solid at room temperature with a strong mothball odor. When molten, appears as a clear to pale yellow liquid above 80°C (176°F).
| Also known as | naphthalenewhite tarmoth ballstar camphornaphthenealbocarbon |
| CAS Number | 91-20-3 |
| Appearance | White crystalline solid at room temperature with a strong mothball odor. When molten, appears as a clear to pale yellow liquid above 80°C (176°F). |
| Flash Point | 79-87°C (174-189°F) |
| Boiling Point | 218°C (424°F) |
| Vapor Density | 4.4 (heavier than air) |
| Water Reactivity | No significant reaction; insoluble in water |
Fireground Response Guidance — UN 2304
Extinguishing Media
PPE Requirements
Use SCBA for fire, vapor or heavy smoke. Wear chemical-resistant and thermal protective clothing, gloves and face protection to prevent molten material burns.
Isolation & Evacuation
First Actions for a UN 2304 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.
- 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 133, shipping papers, SDS, air monitoring and incident command for protective actions.
📋 Copy & Share Field Card
UN 2304 — Naphthalene, moltenUse 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.