UN 2305 — Nitrobenzenesulphonic acid
Placard: Corrosive. ERG Guide 153. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 2305 is Nitrobenzenesulphonic acid, a toxic corrosive aromatic sulfonic acid assigned to ERG Guide 153. Water dissolution can form acidic solutions and generate heat.
Hazard overview: TOXIC and CORROSIVE aromatic sulfonic acid; inhalation, ingestion or skin/eye contact may cause severe injury. Dissolves in water to form acidic solutions and may generate heat during dissolution. Combustible material: may burn but does not ignite readily.
Response guidance: For a UN 2305 incident, verify the product with shipping papers, container markings, SDS and ERG Guide 153. Establish incident command, isolate the area, stay upwind, control ignition or incompatibility hazards, prevent runoff, dust or vapor spread and base entry/fire-control actions on monitoring and local SOP.
Firefighter training notes: Training for UN 2305 should emphasize toxic skin/vapor/dust exposure, contaminated clothing, toxic fire products, decontamination waste and runoff containment. Use ERG 153, SDS and local SOP.
Regulatory context: Nitrobenzenesulphonic acid is regulated as a hazardous material for transportation and emergency response purposes. Storage, workplace exposure, emergency planning, spill reporting, waste handling and environmental requirements vary by exact product, concentration, quantity and jurisdiction. Verify current requirements through shipping papers, SDS, container markings and applicable DOT, OSHA, EPA, NFPA, state or local authority guidance.
Storage & handling: Nitrobenzenesulphonic acid should be stored in tightly closed compatible containers in a secure toxic/corrosive-material area with secondary containment, restricted access, ventilation and waste/decontamination planning according to SDS.
UN 2305 Quick Details
Common Hazards of UN 2305
- TOXIC and CORROSIVE aromatic sulfonic acid; inhalation, ingestion or skin/eye contact may cause severe injury.
- Dissolves in water to form acidic solutions and may generate heat during dissolution.
- Combustible material: may burn but does not ignite readily.
- Dust or solution can burn eyes, skin and respiratory tissue.
- Fire may produce nitrogen oxides, sulfur oxides and other toxic/corrosive gases.
- Runoff may be acidic, toxic and environmentally harmful.
- Containers may rupture or fail when heated.
Chemical Identity & Physical Properties
Yellow to tan crystalline solid or powder with a slightly acidic odor. May appear as yellowish crystals at room temperature.
| Also known as | 3-Nitrobenzenesulfonic acidm-Nitrobenzenesulfonic acidNBSANitrobenzene sulfonic acid |
| CAS Number | 98-47-5 |
| Appearance | Yellow to tan crystalline solid or powder with a slightly acidic odor. May appear as yellowish crystals at room temperature. |
| Flash Point | Not applicable (non-flammable solid) |
| Boiling Point | Decomposes before boiling at elevated temperatures |
| Vapor Density | Not applicable (solid) |
| Water Reactivity | Soluble in water forming acidic solutions; no violent reaction but generates heat on dissolution |
Fireground Response Guidance — UN 2305
Extinguishing Media
PPE Requirements
Use positive-pressure SCBA for vapor, dust, mist, fire or confined-space exposure. Wear chemical-resistant gloves, boots, eye/face protection and protective clothing selected from SDS; avoid all skin contact.
Isolation & Evacuation
First Actions for a UN 2305 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 breathing vapors, dust, mist, smoke or fumes and avoid skin or eye contact.
- Do not touch damaged containers or spilled material unless properly trained and wearing appropriate protective equipment.
- Prevent contaminated liquid, dust, residues, runoff and decontamination waste from spreading.
- Ventilate closed spaces before entering, but only if properly trained, equipped, monitored and authorized by incident command.
- Isolate the spill or release area and expand the perimeter for fire involvement, vapor spread, dust generation, water reaction or unknown product identity.
- Use ERG Guide 153, shipping papers, SDS, air monitoring and incident command for protective actions.
📋 Copy & Share Field Card
UN 2305 — Nitrobenzenesulphonic acidUse 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.