☣️ UN 2978 • CLASS 7
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.
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⚠️ This page is a quick-reference aid. For real incidents: stage upwind, isolate, deny entry, request Hazmat early, and consult the current ERG + SOP/SOG.
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UN 2978 Quick Details
UN 2978
Product name: Uranium hexafluoride, radioactive material, non fissile or fissile-excepted
DOT Class: 7
Placard type: Radioactive
ERG Guide: 166 (check current ERG)
Initial isolation: ERG 166: Isolate spill 100m in all directions. Evacuate 800m downwind if container damaged or leaking. Radiation Authority must be notified immediately.
Common Hazards of UN 2978
- Radiation presents minimal risk to transport workers, emergency response personnel and the public
- Low radiation hazard to people. Chemical hazard greatly exceeds radiation hazard.
- Substance reacts with water and water vapor in air to form toxic and corrosive hydrogen fluoride gas,
- Toxic; may be fatal if inhaled, ingested, or absorbed through skin.
- Direct contact with substance and gas may cause burns to skin, eyes, or respiratory tract.
- Runoff from control of cargo fire may cause low-level pollution.
- Substance does not burn.
- The material may react violently with fuels.
Chemical Identity & Physical Properties
| 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. |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Fireground Response Guidance — UN 2978
Extinguishing Media
Dry chemical or CO2 for surrounding fires only. Do not apply water or foam directly to uranium hexafluoride. Soda ash or lime to neutralize spills.
PPE Requirements
⚠️ Level A minimum for spills or leaks. Full face SCBA required. Chemical-resistant suit. Radiation monitoring equipment. HF vapor protection essential.
Isolation & Evacuation
ERG 166: Isolate spill 100m in all directions. Evacuate 800m downwind if container damaged or leaking. Radiation Authority must be notified immediately.
Always confirm protective actions with the current edition of the Emergency Response Guidebook (ERG Guide 166).
First Actions for a UN 2978 Incident
- CALL 911. Then call emergency response telephone number on shipping paper. If shipping paper
- Priorities for rescue, life-saving, first aid, fire control and other hazards are higher than the
- Radiation Authority must be notified of accident conditions. Radiation Authority is usually responsible for
- Stay upwind, uphill and/or upstream.
- Keep unauthorized personnel away.
- Detain or isolate uninjured persons or equipment suspected to be contaminated; delay decontamination
- Isolate spill or leak area for at least 25 meters (75 feet) in all directions.
- See Table 1 - Initial Isolation and Protective Action Distances.
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📋 Copy & Share Field Card
UN 2978 — Uranium hexafluoride, radioactive materiHAZMAT RADIO NOTE — UN 2978
Product: Uranium hexafluoride, radioactive material, non fissile or fissile-excepted
Class 7 / Radioactive / ERG 166
PPE: Level A minimum for spills or leaks. Full face SCBA required. Chemical-resistant suit. Radiation monitoring equipment. HF vapor protection essential.
ISOLATION: ERG 166: Isolate spill 100m in all directions. Evacuate 800m downwind if container damaged or leaking. Radiation Authority must be notified immediately.
ACTION: Stage upwind · Isolate · Deny entry · Request HazmatRADIO
Use for: Quick radio or face-to-face size-up. Short, structured, field-ready.
=== IC HAZMAT BRIEFING ===
UN 2978 — Uranium hexafluoride, radioactive material, non fissile or fissile-excepted
Class: 7 | Placard: Radioactive | ERG Guide: 166
Appearance: Colorless to white crystalline solid at room temperature, sublimes readily. Pungent, irritating odor. Forms dense white fumes in moist 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.
Extinguishing: Dry chemical or CO2 for surrounding fires only. Do not apply water or foam directly to uranium hexafluoride. Soda ash or lime to neutralize spills.
PPE: Level A minimum for spills or leaks. Full face SCBA required. Chemical-resistant suit. Radiation monitoring equipment. HF vapor protection essential.
Isolation: ERG 166: Isolate spill 100m in all directions. Evacuate 800m downwind if container damaged or leaking. Radiation Authority must be notified immediately.
— Key Hazards —
• Radiation presents minimal risk to transport workers, emergency response personnel and the public
• Low radiation hazard to people. Chemical hazard greatly exceeds radiation hazard.
• Substance reacts with water and water vapor in air to form toxic and corrosive hydrogen fluoride gas,
— First Actions —
• CALL 911. Then call emergency response telephone number on shipping paper. If shipping paper
• Priorities for rescue, life-saving, first aid, fire control and other hazards are higher than the
• Radiation Authority must be notified of accident conditions. Radiation Authority is usually responsible for
• Stay upwind, uphill and/or upstream.
SOURCE: allfirefighter.com/hazmat/un/2978 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief. Full chemical + response details.
UN2978 Uranium hexafluoride, radioactive material, non fissile or fissile-excepted Cls7 ERG166 | allfirefighter.com/hazmat/un/2978SMS / 160 CHAR
Use for: Quick text to command or incoming units. Fits in a single SMS. Includes link to full page.
⚠️ Quick-reference only. Always use current ERG + SOP/SOG for incident-specific actions.
Page: https://allfirefighter.com/hazmat/un/2978
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Frequently Asked Questions about UN 2978
Radiation presents minimal risk to transport workers, emergency response personnel and the public Low radiation hazard to people. Chemical hazard greatly exceeds radiation hazard. Substance reacts with water and water vapor in air to form toxic and corrosive hydrogen fluoride gas, Toxic; may be fatal if inhaled, ingested, or absorbed through skin. Direct contact with substance and gas may cause burns to skin, eyes, or respiratory tract. Runoff from control of cargo fire may cause low-level pollution. Substance does not burn. The material may react violently with fuels.
CALL 911. Then call emergency response telephone number on shipping paper. If shipping paper Priorities for rescue, life-saving, first aid, fire control and other hazards are higher than the Radiation Authority must be notified of accident conditions. Radiation Authority is usually responsible for
Level A minimum for spills or leaks. Full face SCBA required. Chemical-resistant suit. Radiation monitoring equipment. HF vapor protection essential.
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.. Recommended extinguishing: Dry chemical or CO2 for surrounding fires only. Do not apply water or foam directly to uranium hexafluoride. Soda ash or lime to neutralize spills..
ERG Guide 166 recommendation: ERG 166: Isolate spill 100m in all directions. Evacuate 800m downwind if container damaged or leaking. Radiation Authority must be notified immediately.
No. This is a training/quick-reference aid only. Always consult the current ERG Guide 166 and your department SOP/SOG for incident-specific protective actions.
Sources (high level): DOT/PHMSA marking & class concepts + ERG usage principles.
This page does not reproduce ERG guide text—always consult the current ERG for incident-specific protective actions.