☣️ UN 3261 • CLASS 8
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.
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⚠️ 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 3261 Quick Details
UN 3261
Product name: Corrosive solid, acidic, organic, n.o.s.
DOT Class: 8
Placard type: Corrosive
ERG Guide: 154 (check current ERG)
Initial isolation: ERG 154: Initial isolation 25m in all directions; if tank/rail car involved in fire, isolate 800m in all directions and consider evacuation
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
- 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
| 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 |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Fireground Response Guidance — UN 3261
Extinguishing Media
Dry chemical, CO2, or dry sand preferred; avoid direct water streams; fog spray acceptable for cooling
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
ERG 154: Initial isolation 25m in all directions; if tank/rail car involved in fire, isolate 800m in all directions and consider evacuation
Always confirm protective actions with the current edition of the Emergency Response Guidebook (ERG Guide 154).
First Actions for a UN 3261 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.
- 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 at least 25 meters
- For highlighted materials: see Table 1 - Initial Isolation and Protective Action Distances.
- For non-highlighted materials: increase the immediate precautionary measure distance, in the downwind
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UN 3261 — Corrosive solid, acidic, organic, n.o.s.HAZMAT RADIO NOTE — UN 3261
Product: Corrosive solid, acidic, organic, n.o.s.
Class 8 / Corrosive / ERG 154
PPE: Level B minimum required; full face SCBA mandatory; chemical-resistant suit and gloves essential; avoid any skin contact due to severe corrosive nature
ISOLATION: ERG 154: Initial isolation 25m in all directions; if tank/rail car involved in fire, isolate 800m in all directions 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 3261 — Corrosive solid, acidic, organic, n.o.s.
Class: 8 | Placard: Corrosive | ERG Guide: 154
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.
Water Reactivity: May react with water generating heat; reaction severity depends on specific substance; handle with caution around water
Extinguishing: Dry chemical, CO2, or dry sand preferred; avoid direct water streams; fog spray acceptable for cooling
PPE: Level B minimum required; full face SCBA mandatory; chemical-resistant suit and gloves essential; avoid any skin contact due to severe corrosive nature
Isolation: ERG 154: Initial isolation 25m in all directions; if tank/rail car involved in fire, isolate 800m in all directions and consider evacuation
— Key Hazards —
• 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.
— 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.
• Ventilate closed spaces before entering, but only if properly trained and equipped.
SOURCE: allfirefighter.com/hazmat/un/3261 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief. Full chemical + response details.
UN3261 Corrosive solid, acidic, organic, n.o.s. Cls8 ERG154 | allfirefighter.com/hazmat/un/3261SMS / 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/3261
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Frequently Asked Questions about 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 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.
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 required; full face SCBA mandatory; chemical-resistant suit and gloves essential; avoid any skin contact due to severe corrosive nature
Water reactivity: May react with water generating heat; reaction severity depends on specific substance; handle with caution around water. Recommended extinguishing: Dry chemical, CO2, or dry sand preferred; avoid direct water streams; fog spray acceptable for cooling.
ERG Guide 154 recommendation: ERG 154: Initial isolation 25m in all directions; if tank/rail car involved in fire, isolate 800m in all directions and consider evacuation
No. This is a training/quick-reference aid only. Always consult the current ERG Guide 154 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.