UN 1358 — Zirconium powder, wetted with not less than 25% water
Placard: Flammable Solid. ERG Guide 170. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 1358 is Zirconium powder, wetted with not less than 25% water, a Class 4 flammable metal material assigned to ERG Guide 170. Wetted or dry condition matters because fine metal powder can ignite, burn intensely and re-ignite.
Hazard overview: UN 1358 presents flammable metal, dust and incompatible-extinguishing-agent hazards. Fine particles can burn intensely, and water, foam or CO2 may be unsuitable if the material is dry, burning or reactive.
Response guidance: For a UN 1358 incident, responders should verify the product with shipping papers, package markings, SDS and ERG Guide 170. Establish incident command, isolate the area, stay upwind, avoid unnecessary disturbance of powder, piles or damaged packaging, and use only extinguishing agents compatible with the specific material.
Firefighter training notes: Training for UN 1358 should emphasize metal/pyrophoric fire behavior, dust cloud prevention, incompatible extinguishing agents, re-ignition, dry-agent application and safe standoff. Common errors include using water or foam on burning metal, disturbing powder and underestimating metal oxide fumes. Use ERG 170, SDS and metal-fire SOP.
Regulatory context: Zirconium powder, wetted with not less than 25% water is regulated as a hazardous material for transportation and emergency response purposes. Transportation, workplace exposure, spill reporting, waste handling, storage and environmental requirements may vary by formulation, quantity and jurisdiction. Verify current requirements through shipping papers, SDS, facility documents and applicable DOT, OSHA, EPA, NFPA, state or local authority guidance.
Storage & handling: Zirconium powder, wetted with not less than 25% water should be stored in compatible containers away from heat, ignition sources, oxidizers, moisture where incompatible and physical damage. Prevent dust release, container damage and drying of wetted material where wetting is required by SDS.
UN 1358 Quick Details
Common Hazards of UN 1358
- FLAMMABLE zirconium powder; water wetting reduces sensitivity, but dry zirconium powder can ignite readily.
- Dusts or fine particles may burn rapidly or form explosive mixtures in air.
- Metal fires can burn with intense heat and may re-ignite after apparent extinguishment.
- Water or incompatible agents may react with hot or dry metal powder and generate flammable hydrogen.
- Metal oxide fumes from fire may be hazardous to breathe.
- Containers may rupture or explode when heated.
- Avoid creating dust clouds or allowing wetted material to dry unexpectedly.
Chemical Identity & Physical Properties
Gray to black metallic powder, wetted with water to reduce reactivity. Odorless. Shipped as a dampened powder or paste.
| Also known as | Zirconium metal powderWetted zirconiumZirconium dust wettedZr powder |
| CAS Number | 7440-67-7 |
| Appearance | Gray to black metallic powder, wetted with water to reduce reactivity. Odorless. Shipped as a dampened powder or paste. |
| Flash Point | Not applicable (pyrophoric metal) |
| Boiling Point | 4409C (7968F) |
| Vapor Density | Not applicable (solid metal) |
| Water Reactivity | May react violently when dry; wetted form reduces reactivity but must maintain minimum 25% water content to prevent ignition |
Fireground Response Guidance — UN 1358
Extinguishing Media
PPE Requirements
Use positive-pressure SCBA for fire, smoke or dust exposure. Protective clothing, gloves and eye/face protection should follow SDS and metal-fire SOP; PPE does not protect against violent metal fire, dust explosion or container rupture hazards.
Isolation & Evacuation
First Actions for a UN 1358 Incident
- CALL 911. Then call the emergency response telephone number on the shipping paper, if available.
- Keep unauthorized personnel away.
- Stay upwind, uphill and/or upstream.
- Eliminate ignition sources if it is safe to do so.
- Do not create dust clouds or disturb spilled powder unless properly trained and equipped.
- Keep water, foam, CO2 and halogenated agents away from burning or reactive metal unless incident command confirms compatibility.
- Use dry Class D agents, dry sand or other compatible dry media when directed by incident command.
- Isolate the spill or fire area and expand the perimeter if metal powder is burning, dry or dispersed.
- Use ERG Guide 170, shipping papers, SDS and metal-fire SOP for protective actions and entry decisions.
📋 Copy & Share Field Card
UN 1358 — Zirconium powder, wetted with not less tUse 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.