UN 1355 — Trinitrobenzoic acid, wetted with not less than 30% water
Placard: Flammable Solid. ERG Guide 113. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 1355 is Trinitrobenzoic acid, wetted with not less than 30% water, a wetted energetic Class 4 material assigned to ERG Guide 113. The water content reduces sensitivity for transport, but dry material can become a serious explosive hazard.
Hazard overview: UN 1355 presents flammable solid, toxic exposure and dry-out explosive hazards. If the material dries, is fire-exposed or is handled roughly, it may react violently; responders should avoid friction, impact and unnecessary movement.
Response guidance: For a UN 1355 incident, responders should verify the product with shipping papers, package markings, SDS and ERG Guide 113. Establish incident command, isolate the area, stay upwind, avoid unnecessary disturbance of powder or damaged packaging, and use only extinguishing agents compatible with the specific material.
Firefighter training notes: Training for UN 1355 should emphasize desensitized energetic material, dry-out risk, gentle handling, explosive specialist notification and the difference between wetted and dried material. Common errors include letting material dry, scraping or sweeping residue and applying routine fire tactics when drying or fire exposure is suspected.
Regulatory context: Trinitrobenzoic acid, wetted with not less than 30% water is regulated as a hazardous material for transportation and emergency response purposes. Transportation, workplace exposure, spill reporting, waste handling, storage and environmental requirements may vary by formulation, quantity and jurisdiction. Verify current requirements through shipping papers, SDS, facility documents and applicable DOT, OSHA, EPA, NFPA, state or local authority guidance.
Storage & handling: Trinitrobenzoic acid, wetted with not less than 30% water should be stored only in approved packaging with required wetting agent maintained, away from heat, friction, shock, ignition sources and unauthorized access. Drying, damaged packaging or leakage should be treated as a serious escalation and handled under SDS and explosive-material procedures.
UN 1355 Quick Details
Common Hazards of UN 1355
- WETTED energetic solid; water reduces sensitivity but the material may become explosive if it dries.
- Dried-out material may explode if exposed to heat, flame, friction, shock or impact.
- May be ignited by heat, sparks or flames while wetted.
- Some materials in this group are toxic and may be harmful by inhalation, ingestion or skin contact.
- Fire may produce irritating, corrosive and/or toxic gases.
- Runoff may spread contamination and may carry energetic residue.
- If drying, fire exposure or damaged packaging is suspected, treat the material as an explosive hazard.
Chemical Identity & Physical Properties
Pale yellow to tan crystalline solid when wetted. Odorless or slight aromatic odor. Shipped wetted with at least 30% water as a desensitizer to reduce explosive hazard.
| Also known as | TNB2,4,6-Trinitrobenzoic acidPicric acid carboxylic analogTNBA |
| CAS Number | 129-66-8 |
| Appearance | Pale yellow to tan crystalline solid when wetted. Odorless or slight aromatic odor. Shipped wetted with at least 30% water as a desensitizer to reduce explosive hazard. |
| Flash Point | Not applicable (wetted explosive solid) |
| Boiling Point | Not applicable (decomposes) |
| Vapor Density | Not applicable (solid) |
| Water Reactivity | No significant reaction with water; water desensitizes the explosive |
Fireground Response Guidance — UN 1355
Extinguishing Media
PPE Requirements
Use positive-pressure SCBA for fire, vapor or dust exposure. Chemical-resistant gloves and protective clothing should be selected from SDS, but distance, gentle handling, wetting control and explosive-specialist support are more important than PPE if the material is dry or fire-exposed.
Isolation & Evacuation
First Actions for a UN 1355 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.
- Avoid friction, shock, impact or unnecessary handling of packages or spilled material.
- Keep the material wetted according to product guidance and prevent drying when it is safe and authorized to do so.
- If material is dry, fire-exposed or package condition is uncertain, treat it as an explosive hazard and withdraw.
- Ventilate closed spaces before entering, but only if properly trained, equipped and authorized by incident command.
- Isolate the area and request hazmat plus explosive specialist support when drying or fire involvement is suspected.
- Use ERG Guide 113, shipping papers, SDS and incident command for isolation and protective action decisions.
📋 Copy & Share Field Card
UN 1355 — Trinitrobenzoic acid, wetted with not leUse for: Quick radio or face-to-face size-up. Short, structured, field-ready.
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief.
Use for: Quick text to command or incoming units. Fits in a single SMS.