UN 3261 — Corrosive solid, acidic, organic, n.o.s.
Placard: Corrosive. ERG Guide 154. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 3261 Corrosive solid, acidic, organic, n.o.s. is assigned to ERG Guide 154 for initial emergency response. Solid material at room temperature, varying in color and form depending on specific substance. May be crystalline, granular, or powdered; specific physical properties vary by composition as this is a general classification for various organic acidic solids. Verify the exact product from shipping papers and SDS before selecting tactics.
Hazard overview: Primary hazards: a corrosive hazardous material that can cause severe skin, eye and respiratory injury. TOXIC and/or CORROSIVE; inhalation, ingestion or skin contact with material may cause severe injury. Contact with molten substance may cause severe burns to skin and eyes.
Response guidance: For a UN 3261 incident, isolate the area, keep unauthorized personnel away, stay upwind/uphill and confirm the exact material from shipping papers and SDS. Use compatible extinguishing media and prevent contaminated runoff from entering waterways. Follow ERG Guide 154 and local incident command procedures.
UN 3261 Quick Details
Common Hazards of UN 3261
- TOXIC and/or CORROSIVE; inhalation, ingestion or skin contact with material may cause severe injury.
- Contact with molten substance may cause severe burns to skin and eyes.
- Avoid any skin contact.
- Fire may produce irritating, corrosive and/or toxic gases.
- Runoff from fire control or dilution water may be corrosive and/or toxic and cause environmental contamination.
- Non-combustible, substance itself does not burn but may decompose upon heating to produce corrosive.
- Some are oxidizers and may ignite combustibles (wood, paper, oil, clothing, etc.).
- Corrosives in contact with metals may evolve flammable hydrogen gas.
Chemical Identity & Physical Properties
Solid material at room temperature, varying in color and form depending on specific substance. May be crystalline, granular, or powdered; specific physical properties vary by composition as this is a general classification for various organic acidic solids.
| Also known as | Corrosive solid, acidic, organic, not otherwise specifiedAcidic organic corrosive solidOrganic acid solidCorrosive organic solid, acidic |
| Appearance | Solid material at room temperature, varying in color and form depending on specific substance. May be crystalline, granular, or powdered; specific physical properties vary by composition as this is a general classification for various organic acidic solids. |
| Flash Point | Not applicable (solid, varies by specific substance) |
| Boiling Point | Not applicable (varies by specific substance) |
| Vapor Density | Not applicable (solid) |
| Water Reactivity | May react with water generating heat; reaction severity depends on specific substance; handle with caution around water |
Fireground Response Guidance — UN 3261
Extinguishing Media
PPE Requirements
Level B minimum required; full face SCBA mandatory; chemical-resistant suit and gloves essential; avoid any skin contact due to severe corrosive nature
Isolation & Evacuation
First Actions for a UN 3261 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 in all directions for at least 50 meters (150 feet) for liquids and 25 meters (75 feet) for solids.
- For highlighted materials: see Table 1 - Initial Isolation and Protective Action Distances.
- For non-highlighted materials, increase the initial isolation distance in the downwind direction as needed.
📋 Copy & Share Field Card
UN 3261 — Corrosive solid, acidic, organic, n.o.s.Use 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.