UN 3331 — Radioactive material, transported under special arrangement, fissile
Placard: Radioactive. ERG Guide 165. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 3331 At a Glance
UN 3331 (Radioactive material, transported under special arrangement, fissile) is listed as DOT Class 7 Radioactive and is assigned to ERG Guide 165. Use this page to review placard data, common hazards, PPE notes, isolation context, first actions, and related UN numbers.
UN 3331 is Radioactive material, transported under special arrangement, fissile, a fissile radioactive package assigned to ERG Guide 165. Undamaged packages are engineered for containment; damaged packages require radiation authority control.
Hazard overview: RADIOACTIVE fissile package; undamaged packages are designed to maintain shielding, containment and criticality safety. Damaged packages may increase external radiation exposure and create contamination-control concerns. Fissile contents require radiation authority guidance because package geometry, moderation and shielding matter.
Response guidance: For UN 3331, protect life safety first, isolate damaged packages and notify radiation authority. Limit handling, control runoff/debris and use monitoring with ERG 165.
Firefighter training notes: Training for UN 3331 should emphasize package recognition, radiation authority notification, dosimetry/survey use, contamination control, time-distance-shielding and life-safety priority. Use ERG 165 and radiation SOP.
Regulatory context: Radioactive material, transported under special arrangement, fissile is regulated as a hazardous material for transport and emergency response. Storage, reporting, exposure, waste and incident-notification duties depend on quantity, package type, formulation and jurisdiction; verify shipping papers, SDS and authority guidance.
Storage & handling: Radioactive material, transported under special arrangement, fissile should remain in approved radioactive material packages protected from damage, fire, unauthorized access and contamination spread. Follow radiation authority, carrier and package-certificate requirements.
UN 3331 Quick Details
Common Hazards of UN 3331
- RADIOACTIVE fissile package; undamaged packages are designed to maintain shielding, containment and criticality safety.
- Damaged packages may increase external radiation exposure and create contamination-control concerns.
- Fissile contents require radiation authority guidance because package geometry, moderation and shielding matter.
- Transport index and package labels may not fully describe radiation level at every point after damage.
- Some radioactive contents may not be detected by common instruments without proper survey equipment.
- Fire may damage packaging and create contaminated debris or runoff-control issues.
- Life safety, rescue and fire control remain priorities while limiting time, maximizing distance and using shielding.
Chemical Identity & Physical Properties
Variable physical form depending on specific fissile isotope and packaging; may be solid metal, oxide powder, or solution; packages are specially designed and approved for fissile material transport.
| Also known as | Fissile radioactive materialSpecial arrangement fissile materialType AF fissile packageType IF fissile package |
| Appearance | Variable physical form depending on specific fissile isotope and packaging; may be solid metal, oxide powder, or solution; packages are specially designed and approved for fissile material transport. |
| Flash Point | Not applicable (radioactive material) |
| Boiling Point | Not applicable (variable depending on isotope form) |
| Vapor Density | Not applicable (variable depending on isotope form) |
| Water Reactivity | Variable depending on specific isotope; some fissile materials may react with water or moisture; follow package-specific handling instructions |
Fireground Response Guidance — UN 3331
Extinguishing Media
PPE Requirements
Use PPE for the dominant hazard plus dosimetry and radiation monitoring. For fire, use SCBA and turnout gear; minimize time, maximize distance and use shielding.
Isolation & Evacuation
First Actions for a UN 3331 Incident
- Call 911 and notify the radiation authority according to local procedures.
- Protect life safety first while minimizing time near damaged packages.
- Keep unauthorized personnel away and establish incident command.
- Stay upwind, uphill and upstream of smoke, runoff or damaged contents.
- Do not handle damaged packages or loose contents without proper training and radiation monitoring.
- Detain potentially contaminated people or equipment for assessment without delaying urgent medical care.
- Use ERG Guide 165, package labels, shipping papers and radiation monitoring to guide isolation, evacuation and cleanup.
📋 Copy & Share Field Card
UN 3331 — Radioactive material, transported underUse 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.