UN 3078 — Cerium, turnings or gritty powder
Placard: Dangerous When Wet. ERG Guide 138. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 3078 is Cerium, turnings or gritty powder, a dangerous-when-wet metal powder/turnings entry assigned to ERG Guide 138. Water and dust fire hazards are critical.
Hazard overview: DANGEROUS WHEN WET cerium turnings or powder; water or moisture can release flammable hydrogen and heat. Finely divided cerium may ignite from sparks, friction, heat or moist air. Burning metal can produce intense heat and may re-ignite after apparent extinguishment.
Response guidance: For UN 3078, isolate the area, avoid dust/friction and use SCBA. Use Class D or dry media only unless SDS confirms another agent, and watch for re-ignition.
Firefighter training notes: Training for UN 3078 should emphasize exposure routes, SCBA use, vapor/dust monitoring, decontamination, runoff containment and SDS/package verification. Use ERG 138, SDS and local SOP.
Regulatory context: Cerium, turnings or gritty powder 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: Cerium, turnings or gritty powder should be stored dry in tightly closed compatible containers away from heat, sparks, friction, moisture, oxidizers and incompatible materials. Keep compatible dry media available.
UN 3078 Quick Details
Common Hazards of UN 3078
- DANGEROUS WHEN WET cerium turnings or powder; water or moisture can release flammable hydrogen and heat.
- Finely divided cerium may ignite from sparks, friction, heat or moist air.
- Burning metal can produce intense heat and may re-ignite after apparent extinguishment.
- Water, foam, CO2 and halogenated agents can worsen burning metal reactions.
- Dust may form explosive mixtures in air.
- Fire may produce cerium oxide fumes and metal smoke.
- Runoff may create fire, explosion and reactive contamination hazards.
Chemical Identity & Physical Properties
Silvery-white to gray metallic solid, appearing as turnings, gritty powder, or shavings. Odorless. Pyrophoric in finely divided form.
| Also known as | Cerium metalCerium powderCerium filingsCerium shavings |
| CAS Number | 7440-45-1 |
| Appearance | Silvery-white to gray metallic solid, appearing as turnings, gritty powder, or shavings. Odorless. Pyrophoric in finely divided form. |
| Flash Point | Not applicable (pyrophoric metal) |
| Boiling Point | 3443C (6229F) |
| Vapor Density | Not applicable (solid metal) |
| Water Reactivity | Reacts with water producing flammable hydrogen gas and heat. May ignite spontaneously with moist air. Do not use water. |
Fireground Response Guidance — UN 3078
Extinguishing Media
PPE Requirements
Use positive-pressure SCBA for fire, dust or smoke. Wear flame/heat-resistant and chemical-resistant protection; avoid dust and incompatible media.
Isolation & Evacuation
First Actions for a UN 3078 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.
- Avoid dust, friction, sparks and incompatible extinguishing media.
- 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 138, SDS, shipping papers and monitoring to set isolation, evacuation and entry decisions.
📋 Copy & Share Field Card
UN 3078 — Cerium, turnings or gritty powderUse 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.