☣️ UN 3368 • CLASS 4
UN 3368 — Trinitrobenzoic acid, wetted with not less than 10% water
Placard: Flammable Solid. ERG Guide 113. 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.
Trinitrobenzoic acid, wetted with not less than 10% water is shipped wetted to reduce explosive sensitivity. The water content is a critical safety control.
Hazard overview: The material may burn and can become explosive if it dries out or is exposed to heat, flame, friction or shock. Toxic decomposition products may be produced in fire.
Response guidance: Keep the material wet, avoid friction or impact and treat any dried residue as explosive. Isolate the area and follow ERG 113 or explosive guidance if fire is involved.
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UN 3368 Quick Details
UN 3368
Product name: Trinitrobenzoic acid, wetted with not less than 10% water
DOT Class: 4
Placard type: Flammable Solid
ERG Guide: 113 (check current ERG)
Initial isolation: ERG 113: isolate 100m all directions initially; if dry/burning treat as explosive per ERG 112: isolate 500m, evacuate 1600m downwind if involved in fire
Common Hazards of UN 3368
- Flammable/combustible material.
- May be ignited by heat, sparks or flames.
- DRIED OUT material may explode if exposed to heat, flame, friction or shock; treat dried material as an explosive.
- Keep material wet with water or treat as an explosive (GUIDE 112).
- Runoff to sewer may create fire or explosion hazard.
- Some are toxic and may be fatal if inhaled, ingested or absorbed through skin.
- Contact may cause burns to skin and eyes.
- Fire may produce irritating, corrosive and/or toxic gases.
Chemical Identity & Physical Properties
Yellow to light brown crystalline solid when dry. Wetted form appears as damp crystals or paste. Odorless or slight aromatic odor.
| Also known as | 2,4,6-Trinitrobenzoic acidTNB acidPicric acid carboxylic analogTNBA |
| CAS Number | 129-66-8 |
| Appearance | Yellow to light brown crystalline solid when dry. Wetted form appears as damp crystals or paste. Odorless or slight aromatic odor. |
| Flash Point | Not applicable (wetted explosive solid) |
| Boiling Point | Not applicable (decomposes before boiling) |
| Vapor Density | Not applicable (solid) |
| Water Reactivity | No significant reaction with water; water desensitizes the explosive properties |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Fireground Response Guidance — UN 3368
Extinguishing Media
Do not use foam or water directly on dry material; wetted material may be approached with flooding quantities of water; dry chemical or sand for surrounding fires
PPE Requirements
⚠️ Level B minimum with SCBA; full structural firefighter PPE with SCBA; treat as Class 1 explosive if dried out
Use SCBA, full protective clothing and face protection; keep distance and avoid handling dried or contaminated residue.
Isolation & Evacuation
ERG 113: isolate 100m all directions initially; if dry/burning treat as explosive per ERG 112: isolate 500m, evacuate 1600m downwind if involved in fire
Always confirm protective actions with the current edition of the Emergency Response Guidebook (ERG Guide 113).
First Actions for a UN 3368 Incident
- CALL 911. Then call the emergency response telephone number on the shipping paper, if available.
- Keep unauthorized personnel away.
- Stay upwind, uphill and/or upstream.
- Ventilate closed spaces before entering, but only if properly trained and equipped.
- Isolate spill or leak area immediately for at least 100 meters (330 feet) in all directions.
- Consider initial evacuation for 500 meters (1/3 mile) in all directions.
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📋 Copy & Share Field Card
UN 3368 — Trinitrobenzoic acid, wetted with not leHAZMAT RADIO NOTE — UN 3368
Product: Trinitrobenzoic acid, wetted with not less than 10% water
Class 4 / Flammable Solid / ERG 113
PPE: Level B minimum with SCBA; full structural firefighter PPE with SCBA; treat as Class 1 explosive if dried out
ISOLATION: ERG 113: isolate 100m all directions initially; if dry/burning treat as explosive per ERG 112: isolate 500m, evacuate 1600m downwind if 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 3368 — Trinitrobenzoic acid, wetted with not less than 10% water
Class: 4 | Placard: Flammable Solid | ERG Guide: 113
Appearance: Yellow to light brown crystalline solid when dry. Wetted form appears as damp crystals or paste. Odorless or slight aromatic odor.
Water Reactivity: No significant reaction with water; water desensitizes the explosive properties
Extinguishing: Do not use foam or water directly on dry material; wetted material may be approached with flooding quantities of water; dry chemical or sand for surrounding fires
PPE: Level B minimum with SCBA; full structural firefighter PPE with SCBA; treat as Class 1 explosive if dried out
Isolation: ERG 113: isolate 100m all directions initially; if dry/burning treat as explosive per ERG 112: isolate 500m, evacuate 1600m downwind if involved in fire
— Key Hazards —
• Flammable/combustible material.
• May be ignited by heat, sparks or flames.
• DRIED OUT material may explode if exposed to heat, flame, friction or shock; treat dried material as an explosive.
— First Actions —
• CALL 911. Then call the emergency response telephone number on the shipping paper, if available.
• Keep unauthorized personnel away.
• Stay upwind, uphill and/or upstream.
• Ventilate closed spaces before entering, but only if properly trained and equipped.
SOURCE: allfirefighter.com/hazmat/un/trinitrobenzoic-acid-wetted-with-un-3368 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief.
UN3368 Trinitrobenzoic acid, wetted with not less than 10% water Cls4 ERG113 | allfirefighter.com/hazmat/un/trinitrobenzoic-acid-wetted-with-un-3368SMS / 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/trinitrobenzoic-acid-wetted-with-un-3368
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Frequently Asked Questions about UN 3368
UN 3368 is the entry for Trinitrobenzoic acid, wetted with not less than 10% water.
Water reduces sensitivity and helps prevent explosive behavior from drying.
Dried material may become explosive if heated, shocked, struck or exposed to friction.
Water spray or fog may be used to keep material wet; avoid actions that spread contamination or cause impact.
SCBA and full protective clothing are required; responders should maintain distance due to explosive potential.
ERG Guide 113 applies initially, with explosive guidance if material is dry or fire-involved.
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.