☣️ UN 2956 • CLASS 4
UN 2956 — 5-tert-Butyl-2,4,6-trinitrom- xylene
Placard: Flammable Solid. ERG Guide 149. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
🚒☣️
⚠️ 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 2956 Quick Details
UN 2956
Product name: 5-tert-Butyl-2,4,6-trinitrom- xylene
DOT Class: 4
Placard type: Flammable Solid
ERG Guide: 149 (check current ERG)
Initial isolation: ERG 149: isolate 100m in all directions; for large fires isolate 800m and consider evacuation
Common Hazards of UN 2956
- 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.
Chemical Identity & Physical Properties
| Also known as | Musk xylene5-tert-Butyl-2,4,6-trinitro-m-xyleneMusk xylol1-tert-Butyl-3,5-dimethyl-2,4,6-trinitrobenzene |
| CAS Number | 81-15-2 |
| Appearance | Yellow to white crystalline solid with a musk-like odor. Exists as crystals or powder at room temperature. |
| Flash Point | Not applicable (explosive solid) |
| Boiling Point | Decomposes at approximately 205C (401F) |
| Vapor Density | Not applicable (solid) |
| Water Reactivity | Insoluble in water; no significant reaction with water |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Fireground Response Guidance — UN 2956
Extinguishing Media
Do not use water streams; dry chemical, sand, or dry extinguishing agents only
PPE Requirements
⚠️ Level B minimum with full face SCBA; structural firefighter gear not adequate for contact
Isolation & Evacuation
ERG 149: isolate 100m in all directions; for large fires isolate 800m and consider evacuation
Always confirm protective actions with the current edition of the Emergency Response Guidebook (ERG Guide 149).
First Actions for a UN 2956 Incident
- 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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📋 Copy & Share Field Card
UN 2956 — 5-tert-Butyl-2,4,6-trinitrom- xyleneHAZMAT RADIO NOTE — UN 2956
Product: 5-tert-Butyl-2,4,6-trinitrom- xylene
Class 4 / Flammable Solid / ERG 149
PPE: Level B minimum with full face SCBA; structural firefighter gear not adequate for contact
ISOLATION: ERG 149: isolate 100m in all directions; for large fires isolate 800m 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 2956 — 5-tert-Butyl-2,4,6-trinitrom- xylene
Class: 4 | Placard: Flammable Solid | ERG Guide: 149
Appearance: Yellow to white crystalline solid with a musk-like odor. Exists as crystals or powder at room temperature.
Water Reactivity: Insoluble in water; no significant reaction with water
Extinguishing: Do not use water streams; dry chemical, sand, or dry extinguishing agents only
PPE: Level B minimum with full face SCBA; structural firefighter gear not adequate for contact
Isolation: ERG 149: isolate 100m in all directions; for large fires isolate 800m and consider evacuation
— 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/2956 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief. Full chemical + response details.
UN2956 5-tert-Butyl-2,4,6-trinitrom- xylene Cls4 ERG149 | allfirefighter.com/hazmat/un/2956SMS / 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/2956
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Frequently Asked Questions about UN 2956
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 with full face SCBA; structural firefighter gear not adequate for contact
Water reactivity: Insoluble in water; no significant reaction with water. Recommended extinguishing: Do not use water streams; dry chemical, sand, or dry extinguishing agents only.
ERG Guide 149 recommendation: ERG 149: isolate 100m in all directions; for large fires isolate 800m and consider evacuation
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.