☣️ UN 3126 • CLASS 4
UN 3126 — Self-heating solid, corrosive, organic, n.o.s.
Placard: Spontaneously Combustible. ERG Guide 136. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
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⚠️ Verification required:
Broad or variable material category; verify exact product, SDS and shipping papers.
⚠️ 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.
Self-heating solid, corrosive, 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.
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UN 3126 Quick Details
UN 3126
Product name: Self-heating solid, corrosive, organic, n.o.s.
DOT Class: 4
Placard type: Spontaneously Combustible
ERG Guide: 136 (check current ERG)
Initial isolation: Use ERG 136 as initial guidance, then adjust isolation using SDS, shipping papers, monitoring data, wind and package condition.
Common Hazards of UN 3126
- Corrosive to skin, eyes and some metals; contact with metals may generate flammable hydrogen gas.
- 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 corrosive organic NOSSpontaneously combustible solid corrosive organicPyrophoric corrosive organic solid |
| Appearance | Variable appearance depending on specific substance; typically a solid material that may be in molten form during transport. Can spontaneously ignite when exposed to air and burns rapidly producing dense white irritating fumes. |
| Flash Point | Not applicable (self-heating/spontaneously combustible material) |
| Boiling Point | Not applicable (varies by specific substance; may be transported molten) |
| Vapor Density | Not applicable (solid material) |
| Water Reactivity | May react with water due to corrosive nature; reaction severity varies by specific substance |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Fireground Response Guidance — UN 3126
Extinguishing Media
Dry chemical, sand, dry dolomite, soda ash; DO NOT use water or foam on burning material
PPE Requirements
⚠️ SCBA and chemical-resistant protection required. Use Level A for unknown identity, active gas release or major spill; Level B only when monitoring supports it.
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
Use ERG 136 as initial guidance, then adjust isolation using SDS, shipping papers, monitoring data, wind and package condition.
Always confirm protective actions with the current edition of the Emergency Response Guidebook (ERG Guide 136).
First Actions for a UN 3126 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.
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📋 Copy & Share Field Card
UN 3126 — Self-heating solid, corrosive, organic,HAZMAT RADIO NOTE — UN 3126
Product: Self-heating solid, corrosive, organic, n.o.s.
Class 4 / Spontaneously Combustible / ERG 136
PPE: SCBA and chemical-resistant protection required. Use Level A for unknown identity, active gas release or major spill; Level B only when monitoring supports it.
ISOLATION: Use ERG 136 as initial guidance, then adjust isolation using SDS, shipping papers, monitoring data, wind and package condition.
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 3126 — Self-heating solid, corrosive, organic, n.o.s.
Class: 4 | Placard: Spontaneously Combustible | ERG Guide: 136
Appearance: Variable appearance depending on specific substance; typically a solid material that may be in molten form during transport. Can spontaneously ignite when exposed to air and burns rapidly producing dense white irritating fumes.
Water Reactivity: May react with water due to corrosive nature; reaction severity varies by specific substance
Extinguishing: Dry chemical, sand, dry dolomite, soda ash; DO NOT use water or foam on burning material
PPE: SCBA and chemical-resistant protection required. Use Level A for unknown identity, active gas release or major spill; Level B only when monitoring supports it.
Isolation: Use ERG 136 as initial guidance, then adjust isolation using SDS, shipping papers, monitoring data, wind and package condition.
— Key Hazards —
• Corrosive to skin, eyes and some metals; contact with metals may generate flammable hydrogen gas.
• Containers may rupture or explode when heated.
• Fire may produce irritating, toxic or corrosive smoke and runoff.
— First Actions —
• 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.
SOURCE: allfirefighter.com/hazmat/un/self-heating-solid-corrosive-un-3126 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief.
UN3126 Self-heating solid, corrosive, organic, n.o.s. Cls4 ERG136 | allfirefighter.com/hazmat/un/self-heating-solid-corrosive-un-3126SMS / 160 CHAR
Use for: Quick text to command or incoming units. Fits in a single SMS.
⚠️ Quick-reference only. Always use current ERG + SOP/SOG for incident-specific actions.
Page: https://allfirefighter.com/hazmat/un/self-heating-solid-corrosive-un-3126
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Frequently Asked Questions about UN 3126
It covers a broad n.o.s. solid category. The exact chemical, concentration and additives must be confirmed from the SDS and shipping papers.
The entry is broad or variable, so one fixed behavior cannot be assumed for every shipment.
Water behavior varies by product. Check SDS before applying water directly.
SCBA and chemical-resistant clothing are needed. Use Level A for unknown products, active vapor/gas release or major spills.
Check shipping papers, SDS, package markings, wind direction and atmospheric monitoring before committing crews.
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.