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 At a Glance
UN 2977 (Radioactive material, uranium hexafluoride, fissile) is listed as DOT Class 7 Radioactive and is assigned to ERG Guide 166. Use this page to review placard data, common hazards, PPE notes, isolation context, first actions, and related UN numbers.
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.