☣️ UN 3124 • CLASS 6
UN 3124 — Poisonous solid, self-heating, n.o.s.
Placard: Toxic. ERG Guide 136. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
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⚠️ 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.
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UN 3124 Quick Details
UN 3124
Product name: Poisonous solid, self-heating, n.o.s.
DOT Class: 6
Placard type: Toxic
ERG Guide: 136 (check current ERG)
Initial isolation: ERG 136: isolate spill area minimum 25m all directions; if fire or large spill, isolate 800m in all directions and consider evacuation
Common Hazards of UN 3124
- Extremely flammable; will ignite itself if exposed to air.
- Burns rapidly, releasing dense, white, irritating fumes.
- Substance may be transported in a molten form.
- May re-ignite after fire is extinguished.
- Corrosives in contact with metals may evolve flammable hydrogen gas.
- Containers may explode when heated.
- Fire will produce irritating, corrosive and/or toxic gases.
- TOXIC and/or CORROSIVE; ingestion of substance or inhalation of decomposition products will cause
Chemical Identity & Physical Properties
| Also known as | Toxic solid, self-heating, not otherwise specifiedSelf-heating poisonous solidSelf-heating toxic solid N.O.S. |
| Appearance | Variable appearance depending on specific substance; typically a solid material that can spontaneously heat and ignite when exposed to air. May be transported in molten form at elevated temperatures. |
| Flash Point | Not applicable (self-heating material, spontaneous ignition hazard) |
| Boiling Point | Variable depending on specific substance |
| Vapor Density | Variable depending on specific substance |
| Water Reactivity | Variable depending on specific substance; avoid water unless material is confirmed compatible |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Fireground Response Guidance — UN 3124
Extinguishing Media
Dry chemical, dry sand, soda ash; no water unless specifically approved for material
PPE Requirements
⚠️ Level A or B required; SCBA mandatory; full chemical protective suit; material is both toxic and self-heating
Isolation & Evacuation
ERG 136: isolate spill area minimum 25m all directions; if fire or large spill, isolate 800m in all directions and consider evacuation
Always confirm protective actions with the current edition of the Emergency Response Guidebook (ERG Guide 136).
First Actions for a UN 3124 Incident
- CALL 911. Then call emergency response telephone number on shipping paper. If shipping paper
- Stay upwind, uphill and/or upstream.
- Keep unauthorized personnel away.
- Isolate spill or leak area in all directions for at least 50 meters (150 feet) for liquids and at least 25 meters
- For highlighted materials: see Table 1 - Initial Isolation and Protective Action Distances.
- For non-highlighted materials: increase the immediate precautionary measure distance, in the downwind
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📋 Copy & Share Field Card
UN 3124 — Poisonous solid, self-heating, n.o.s.HAZMAT RADIO NOTE — UN 3124
Product: Poisonous solid, self-heating, n.o.s.
Class 6 / Toxic / ERG 136
PPE: Level A or B required; SCBA mandatory; full chemical protective suit; material is both toxic and self-heating
ISOLATION: ERG 136: isolate spill area minimum 25m all directions; if fire or large spill, isolate 800m in all directions and consider evacuation
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 3124 — Poisonous solid, self-heating, n.o.s.
Class: 6 | Placard: Toxic | ERG Guide: 136
Appearance: Variable appearance depending on specific substance; typically a solid material that can spontaneously heat and ignite when exposed to air. May be transported in molten form at elevated temperatures.
Water Reactivity: Variable depending on specific substance; avoid water unless material is confirmed compatible
Extinguishing: Dry chemical, dry sand, soda ash; no water unless specifically approved for material
PPE: Level A or B required; SCBA mandatory; full chemical protective suit; material is both toxic and self-heating
Isolation: ERG 136: isolate spill area minimum 25m all directions; if fire or large spill, isolate 800m in all directions and consider evacuation
— Key Hazards —
• Extremely flammable; will ignite itself if exposed to air.
• Burns rapidly, releasing dense, white, irritating fumes.
• Substance may be transported in a molten form.
— First Actions —
• CALL 911. Then call emergency response telephone number on shipping paper. If shipping paper
• Stay upwind, uphill and/or upstream.
• Keep unauthorized personnel away.
• Isolate spill or leak area in all directions for at least 50 meters (150 feet) for liquids and at least 25 meters
SOURCE: allfirefighter.com/hazmat/un/3124 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief. Full chemical + response details.
UN3124 Poisonous solid, self-heating, n.o.s. Cls6 ERG136 | allfirefighter.com/hazmat/un/3124SMS / 160 CHAR
Use for: Quick text to command or incoming units. Fits in a single SMS. Includes link to full page.
⚠️ Quick-reference only. Always use current ERG + SOP/SOG for incident-specific actions.
Page: https://allfirefighter.com/hazmat/un/3124
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Frequently Asked Questions about UN 3124
Extremely flammable; will ignite itself if exposed to air. Burns rapidly, releasing dense, white, irritating fumes. Substance may be transported in a molten form. May re-ignite after fire is extinguished. Corrosives in contact with metals may evolve flammable hydrogen gas. Containers may explode when heated. Fire will produce irritating, corrosive and/or toxic gases. TOXIC and/or CORROSIVE; ingestion of substance or inhalation of decomposition products will cause
CALL 911. Then call emergency response telephone number on shipping paper. If shipping paper Stay upwind, uphill and/or upstream. Keep unauthorized personnel away.
Level A or B required; SCBA mandatory; full chemical protective suit; material is both toxic and self-heating
Water reactivity: Variable depending on specific substance; avoid water unless material is confirmed compatible. Recommended extinguishing: Dry chemical, dry sand, soda ash; no water unless specifically approved for material.
ERG Guide 136 recommendation: ERG 136: isolate spill area minimum 25m all directions; if fire or large spill, isolate 800m in all directions and consider evacuation
No. This is a training/quick-reference aid only. Always consult the current ERG Guide 136 and your department SOP/SOG for incident-specific protective actions.
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.