UN 3128 — Self-heating solid, poisonous, organic, n.o.s.
Placard: Spontaneously Combustible. ERG Guide 136. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
Self-heating solid, poisonous, organic, n.o.s. is a broad n.o.s. hazmat entry. The material family gives important initial clues, but responders must confirm the exact product, concentration and packaging from shipping papers and the SDS.
Hazard overview: Treat this entry as variable and product-specific. Main concerns include toxic exposure, fire or reaction hazards, container failure when heated, and incompatible contact with water, air, fuels or metals depending on the exact substance.
Response guidance: Set isolation, keep responders upwind and avoid direct contact. Do not apply water or foam to water-reactive material unless compatibility is confirmed. Use ERG guidance first, then refine with SDS, shipping papers and monitoring.
UN 3128 Quick Details
Common Hazards of UN 3128
- Toxic by inhalation, ingestion or skin contact; dust, vapor or decomposition products may cause serious injury.
- Containers may rupture or explode when heated.
- Fire may produce irritating, toxic or corrosive smoke and runoff.
- Because this is an n.o.s. entry, the SDS and shipping papers define the exact hazards and response limits.
Chemical Identity & Physical Properties
Physical appearance is product-specific. This entry covers solid materials that may vary in color, odor, concentration and packaging, so visual identification alone is not reliable.
| Also known as | Self-heating solid, toxic, organic, n.o.s.Organic toxic self-heating solidClass 4.2 toxic organic solid |
| Appearance | Varies by specific substance; typically a solid material that may be transported in molten form. Can spontaneously heat and ignite when exposed to air. Burns rapidly producing dense white irritating fumes. |
| Flash Point | Not applicable (self-heating solid, spontaneously combustible) |
| Boiling Point | Varies by specific substance in n.o.s. classification |
| Vapor Density | Not applicable (solid material) |
| Water Reactivity | May react with water depending on specific substance; water may not be effective extinguishing agent |
Fireground Response Guidance — UN 3128
Extinguishing Media
PPE Requirements
Use SCBA and chemical-resistant protection. Level A is preferred for unknown identity, vapor/gas release or major spill; Level B may be used only with monitoring and command approval.
Isolation & Evacuation
First Actions for a UN 3128 Incident
- Call 911 and the emergency response number shown on shipping papers.
- Keep unauthorized personnel away and establish an isolation zone.
- Stay upwind, uphill and upstream; avoid low areas where vapors or gases may collect.
- Avoid breathing vapors, dust, smoke or decomposition gases and avoid skin or eye contact.
- Do not touch damaged packages, containers or spilled material without proper PPE.
- Ventilate confined spaces only if responders are trained, equipped and monitoring the atmosphere.
- Use ERG, SDS, shipping papers and monitoring results for final isolation and response decisions.
📋 Copy & Share Field Card
UN 3128 — Self-heating solid, poisonous, organic,Use 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.