UN 1376 — Iron sponge, spent
Placard: Spontaneously Combustible. ERG Guide 135. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 1376 is Iron sponge, spent, a Class 4 spontaneously combustible metal/catalyst material assigned to ERG Guide 135. Drying, air exposure or disturbance can create pyrophoric ignition and metal-fire hazards.
Hazard overview: UN 1376 presents pyrophoric, dust and metal-fire hazards. Wetting may suppress ignition, but dry catalyst or spent metal residue can ignite when exposed to air and may react poorly with common extinguishing agents.
Response guidance: For a UN 1376 incident, responders should verify the product with shipping papers, package markings, SDS and ERG Guide 135. 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 1376 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 135, SDS and metal-fire SOP.
Regulatory context: Iron sponge, spent 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: Iron sponge, spent 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 1376 Quick Details
Common Hazards of UN 1376
- SPONTANEOUSLY COMBUSTIBLE; may self-heat or ignite when exposed to air, moisture or friction.
- Spent metal or catalyst residues may retain sulfur, hydrocarbons or other process contaminants.
- Dust or porous material may ignite rapidly when disturbed.
- Fire may produce metal oxide fumes and irritating or toxic smoke.
- Water or foam may be unsuitable for some dry or reactive residues; verify SDS.
- Material may re-ignite after apparent extinguishment.
- Avoid generating dust and protect from moisture or air exposure when required.
Chemical Identity & Physical Properties
Dark brown to black porous solid material with a characteristic sulfurous odor. Consists of spent iron oxide that has been used in gas purification processes.
| Also known as | Spent iron oxideSpent iron spongeIron oxide desulfurizing massSpent desulfurizing ironPyrophoric iron |
| Appearance | Dark brown to black porous solid material with a characteristic sulfurous odor. Consists of spent iron oxide that has been used in gas purification processes. |
| Flash Point | Not applicable (pyrophoric solid) |
| Boiling Point | Not applicable (solid material) |
| Vapor Density | Not applicable (solid) |
| Water Reactivity | May react with moisture generating heat; can ignite spontaneously when wet or exposed to humid air |
Fireground Response Guidance — UN 1376
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 1376 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 135, shipping papers, SDS and metal-fire SOP for protective actions and entry decisions.
📋 Copy & Share Field Card
UN 1376 — Iron sponge, spentUse 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.