UN 2978 — Uranium hexafluoride, radioactive material, non fissile or fissile-excepted
Placard: Radioactive. ERG Guide 166. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 2978 At a Glance
UN 2978 (Uranium hexafluoride, radioactive material, non fissile or…) 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 2978 is Uranium hexafluoride, radioactive material, non fissile or fissile-excepted, 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 2978, 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 2978 should emphasize UF6 hydrolysis, HF exposure, radiation monitoring, cylinder damage, contamination control and authority notification. Use ERG 166 and radiation SOP.
Regulatory context: Uranium hexafluoride, radioactive material, non fissile or fissile-excepted 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: Uranium hexafluoride, radioactive material, non fissile or fissile-excepted must be stored only in approved cylinders/packages protected from damage, fire, moisture and unauthorized access, with radiation and HF emergency planning.
UN 2978 Quick Details
Common Hazards of UN 2978
- 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. Pungent, irritating odor. Forms dense white fumes in moist air.
| Also known as | UF6Uranium(VI) fluorideHexDepleted uranium hexafluorideEnriched uranium hexafluoride |
| CAS Number | 7783-81-5 |
| Appearance | Colorless to white crystalline solid at room temperature, sublimes readily. Pungent, irritating odor. Forms dense white fumes in moist air. |
| Flash Point | Not applicable (non-flammable solid) |
| Boiling Point | 56.5C (133.7F) sublimes directly from solid to gas |
| Vapor Density | 13 (much heavier than air) |
| Water Reactivity | Reacts violently with water and moisture to form highly toxic and corrosive hydrogen fluoride (HF) gas and uranyl fluoride. Do not use water directly on substance. |
Fireground Response Guidance — UN 2978
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 2978 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 2978 — Uranium hexafluoride, radioactive materiUse 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.