UN 2977 — Radioactive material, uranium hexafluoride, fissile
Placard: Radioactive. ERG Guide 166. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 2977 is Radioactive material, uranium hexafluoride, fissile, a radioactive toxic corrosive UF6 entry assigned to ERG Guide 166. Moisture creates HF and uranium contamination.
Hazard overview: RADIOACTIVE, TOXIC and CORROSIVE uranium hexafluoride; damaged packages can release chemical and radiological hazards. Reacts with moisture to form hydrogen fluoride and uranyl fluoride, both highly toxic/corrosive. HF vapors can severely burn eyes, skin and respiratory tissue.
Response guidance: For UN 2977, isolate the area, control moisture contact and use SCBA with chemical protection. Contain HF/toxic runoff and request specialist support under ERG 166.
Firefighter training notes: Training for UN 2977 should emphasize UF6 hydrolysis, HF exposure, radiation monitoring, cylinder damage, contamination control and authority notification. Use ERG 166 and radiation SOP.
Regulatory context: Radioactive material, uranium hexafluoride, fissile is regulated as a hazardous material for transport and emergency response. Storage, reporting, exposure, waste and incident-notification duties depend on quantity, formulation and jurisdiction; verify shipping papers, SDS and authority guidance.
Storage & handling: Radioactive material, uranium hexafluoride, fissile must be stored only in approved cylinders/packages protected from damage, fire, moisture and unauthorized access, with radiation and HF emergency planning.
UN 2977 Quick Details
Common Hazards of UN 2977
- RADIOACTIVE, TOXIC and CORROSIVE uranium hexafluoride; damaged packages can release chemical and radiological hazards.
- Reacts with moisture to form hydrogen fluoride and uranyl fluoride, both highly toxic/corrosive.
- HF vapors can severely burn eyes, skin and respiratory tissue.
- Radioactive contamination may spread through dust, condensate, runoff or damaged cylinders.
- Cylinders exposed to fire may rupture or release toxic/corrosive radioactive material.
- Runoff may be acidic, fluoride-contaminated and radioactive.
- Specialist radiation and hazmat authority guidance is required.
Chemical Identity & Physical Properties
Colorless to white crystalline solid at room temperature. Sublimes readily to form a colorless, highly reactive gas. Pungent, acrid odor due to formation of hydrogen fluoride in moist air.
| Also known as | Uranium hexafluorideUF6Uranium(VI) fluorideHexFissile uranium hexafluoride |
| CAS Number | 7783-81-5 |
| Appearance | Colorless to white crystalline solid at room temperature. Sublimes readily to form a colorless, highly reactive gas. Pungent, acrid odor due to formation of hydrogen fluoride in moist air. |
| Flash Point | Not applicable (non-flammable inorganic compound) |
| Boiling Point | 56.5C (133.7F) - sublimes directly from solid to gas at atmospheric pressure |
| Vapor Density | 13 (much heavier than air) |
| Water Reactivity | Reacts vigorously with water and moisture to form highly toxic and corrosive hydrogen fluoride (HF) and uranyl fluoride. Chemical hazard greatly exceeds radiation hazard. |
Fireground Response Guidance — UN 2977
Extinguishing Media
PPE Requirements
Use positive-pressure SCBA, chemical protection for HF/uranium compounds and radiation monitoring/dosimetry. Specialist hazmat/radiation support is required.
Isolation & Evacuation
First Actions for a UN 2977 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, gas, mist, smoke or fumes and avoid skin or eye contact.
- Keep water or moisture contact controlled because reaction, toxic fuming or re-ignition hazards may be severe.
- Do not touch damaged containers or spilled material without proper training and PPE.
- Prevent contaminated liquid, dust, runoff and decontamination waste from spreading.
- Ventilate confined spaces only after monitoring and only if properly trained and equipped.
- Use ERG Guide 166, SDS, shipping papers and monitoring to set isolation, evacuation and entry decisions.
📋 Copy & Share Field Card
UN 2977 — Radioactive material, uranium hexafluoriUse 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.