☣️ UN 3222 • CLASS 4
Self-reactive solid type B
Placard: Flammable Solid. 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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Quick details
UN 3222
Class: 4
Placard type: Flammable Solid
ERG: Guide 149 (check current ERG)
Isolation: ERG 149: isolate spill 25-50m all directions; for fire isolate 800m all directions and evacuate 800m in all directions; consider evacuation of 1600m downwind if tank/rail car involved in fire
Chemical & Response Details
| Also known as | Self-reactive solid type BOrganic peroxide type solidTemperature-controlled self-reactive substanceThermally unstable organic solid |
| Appearance | Solid material at room temperature, typically white to off-white or colored powder or granular form. May be odorless or have characteristic chemical odor depending on specific compound. Requires temperature control during transport. |
| Flash Point | Not applicable (self-reactive solid) |
| Boiling Point | Not applicable (decomposes before boiling) |
| Vapor Density | Not applicable (solid) |
| Water Reactivity | Generally no violent water reaction, but water may accelerate decomposition in some cases |
| Extinguishing | Dry chemical, CO2, sand, or inert materials; avoid water spray on bulk material |
| PPE | ⚠️ Level B minimum for spills; SCBA and full protective clothing required for fire involvement; respiratory protection mandatory |
| Isolation | ERG 149: isolate spill 25-50m all directions; for fire isolate 800m all directions and evacuate 800m in all directions; consider evacuation of 1600m downwind if tank/rail car involved in fire |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Common hazards (high level)
- Self-decomposition, self-polymerization, or self-ignition may be triggered by heat, chemical
- May be ignited by heat, sparks or flames.
- Some may decompose explosively when heated or involved in a fire.
- Those substances designated with a (P) may polymerize explosively when heated or involved in a fire.
- May burn violently. Decomposition or polymerization may be self-accelerating and produce large
- Vapors or dust may form explosive mixtures with air.
- Inhalation or contact with vapors, substance or decomposition products may cause severe injury or
- May produce irritating, toxic and/or corrosive gases.
First actions (field-minded)
- CALL 911. Then call emergency response telephone number on shipping paper. If shipping paper
- Keep unauthorized personnel away.
- Stay upwind, uphill and/or upstream.
- Isolate spill or leak area in all directions for at least 50 meters (150 feet) for liquids and at least 25 meters
- Consider initial evacuation for at least 250 meters (800 feet) in all directions.
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UN 3222 — Self-reactive solid type B HAZMAT RADIO NOTE — UN 3222
Product: Self-reactive solid type B
Class 4 / Flammable Solid / ERG 149
PPE: Level B minimum for spills; SCBA and full protective clothing required for fire involvement; respiratory protection mandatory
ISOLATION: ERG 149: isolate spill 25-50m all directions; for fire isolate 800m all directions and evacuate 800m in all directions; consider evacuation of 1600m downwind if tank/rail car involved in fire
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 3222 — Self-reactive solid type B
Class: 4 | Placard: Flammable Solid | ERG Guide: 149
Appearance: Solid material at room temperature, typically white to off-white or colored powder or granular form. May be odorless or have characteristic chemical odor depending on specific compound. Requires temperature control during transport.
Water Reactivity: Generally no violent water reaction, but water may accelerate decomposition in some cases
Extinguishing: Dry chemical, CO2, sand, or inert materials; avoid water spray on bulk material
PPE: Level B minimum for spills; SCBA and full protective clothing required for fire involvement; respiratory protection mandatory
Isolation: ERG 149: isolate spill 25-50m all directions; for fire isolate 800m all directions and evacuate 800m in all directions; consider evacuation of 1600m downwind if tank/rail car involved in fire
— Key Hazards —
• Self-decomposition, self-polymerization, or self-ignition may be triggered by heat, chemical
• May be ignited by heat, sparks or flames.
• Some may decompose explosively when heated or involved in a fire.
— First Actions —
• CALL 911. Then call emergency response telephone number on shipping paper. If shipping paper
• Keep unauthorized personnel away.
• Stay upwind, uphill and/or upstream.
• 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/3222 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief. Full chemical + response details.
UN3222 Self-reactive solid type B Cls4 ERG149 | allfirefighter.com/hazmat/un/3222SMS / 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/3222
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FAQ
Self-decomposition, self-polymerization, or self-ignition may be triggered by heat, chemical May be ignited by heat, sparks or flames. Some may decompose explosively when heated or involved in a fire. Those substances designated with a (P) may polymerize explosively when heated or involved in a fire. May burn violently. Decomposition or polymerization may be self-accelerating and produce large Vapors or dust may form explosive mixtures with air. Inhalation or contact with vapors, substance or decomposition products may cause severe injury or May produce irritating, toxic and/or corrosive gases.
CALL 911. Then call emergency response telephone number on shipping paper. If shipping paper Keep unauthorized personnel away. Stay upwind, uphill and/or upstream.
Level B minimum for spills; SCBA and full protective clothing required for fire involvement; respiratory protection mandatory
No. This is a training/quick-reference aid only. Always consult the current ERG Guide 149 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.