☣️ UN 3257 • CLASS 9
UN 3257 — Elevated temperature liquid, n.o.s., at or above 100°C (212°F), and below its flash point
Placard: Miscellaneous. ERG Guide 171. 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 3257 Quick Details
UN 3257
Product name: Elevated temperature liquid, n.o.s., at or above 100°C (212°F), and below its flash point
DOT Class: 9
Placard type: Miscellaneous
ERG Guide: 171 (check current ERG)
Initial isolation: ERG 171: Isolate spill area at least 25m in all directions; container rupture risk from cooling/heating cycles requires safe distance from fire exposure
Common Hazards of UN 3257
- Some may burn but none ignite readily.
- Containers may explode when heated.
- Some may be transported hot.
- For UN3508, Capacitor, asymmetric, be aware of possible short circuiting as this product is transported
- Polymeric beads, expandable (UN2211) may evolve flammable vapours.
- Inhalation of material may be harmful.
- Contact may cause burns to skin and eyes.
- Inhalation of Asbestos dust may have a damaging effect on the lungs.
Chemical Identity & Physical Properties
| Appearance | Variable appearance depending on specific substance. Liquid transported and maintained at temperatures between 100°C and its flash point. May emit visible heat shimmer or vapors. |
| Flash Point | Above 100°C (212°F) by definition - varies by specific substance |
| Boiling Point | Variable - typically above 100°C (212°F) |
| Vapor Density | Variable depending on specific substance |
| Water Reactivity | Variable - some materials may react with water when hot, creating steam hazard from rapid cooling |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Fireground Response Guidance — UN 3257
Extinguishing Media
Dry chemical, CO2, or foam appropriate for specific substance; avoid direct water application due to temperature differential and potential spattering
PPE Requirements
⚠️ Thermal protective clothing required; chemical-resistant gloves rated for high temperature; face shield; SCBA for vapor exposure or confined spaces
Isolation & Evacuation
ERG 171: Isolate spill area at least 25m in all directions; container rupture risk from cooling/heating cycles requires safe distance from fire exposure
Always confirm protective actions with the current edition of the Emergency Response Guidebook (ERG Guide 171).
First Actions for a UN 3257 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.
- 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 3257 — Elevated temperature liquid, n.o.s., atHAZMAT RADIO NOTE — UN 3257
Product: Elevated temperature liquid, n.o.s., at or above 100°C (212°F), and below its flash point
Class 9 / Miscellaneous / ERG 171
PPE: Thermal protective clothing required; chemical-resistant gloves rated for high temperature; face shield; SCBA for vapor exposure or confined spaces
ISOLATION: ERG 171: Isolate spill area at least 25m in all directions; container rupture risk from cooling/heating cycles requires safe distance from fire exposure
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 3257 — Elevated temperature liquid, n.o.s., at or above 100°C (212°F), and below its flash point
Class: 9 | Placard: Miscellaneous | ERG Guide: 171
Appearance: Variable appearance depending on specific substance. Liquid transported and maintained at temperatures between 100°C and its flash point. May emit visible heat shimmer or vapors.
Water Reactivity: Variable - some materials may react with water when hot, creating steam hazard from rapid cooling
Extinguishing: Dry chemical, CO2, or foam appropriate for specific substance; avoid direct water application due to temperature differential and potential spattering
PPE: Thermal protective clothing required; chemical-resistant gloves rated for high temperature; face shield; SCBA for vapor exposure or confined spaces
Isolation: ERG 171: Isolate spill area at least 25m in all directions; container rupture risk from cooling/heating cycles requires safe distance from fire exposure
— Key Hazards —
• Some may burn but none ignite readily.
• Containers may explode when heated.
• Some may be transported hot.
— 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.
• Isolate spill or leak area in all directions for at least 50 meters (150 feet) for liquids and at least 25 meters
SOURCE: allfirefighter.com/hazmat/un/3257 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief. Full chemical + response details.
UN3257 Elevated temperature liquid, n.o.s., at or above 100°C (212°F), and below its flash point Cls9 ERG171 | allfirefighter.com/hazmat/un/3257SMS / 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/3257
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Frequently Asked Questions about UN 3257
Some may burn but none ignite readily. Containers may explode when heated. Some may be transported hot. For UN3508, Capacitor, asymmetric, be aware of possible short circuiting as this product is transported Polymeric beads, expandable (UN2211) may evolve flammable vapours. Inhalation of material may be harmful. Contact may cause burns to skin and eyes. Inhalation of Asbestos dust may have a damaging effect on the lungs.
CALL 911. Then call emergency response telephone number on shipping paper. If shipping paper Keep unauthorized personnel away. Stay upwind, uphill and/or upstream.
Thermal protective clothing required; chemical-resistant gloves rated for high temperature; face shield; SCBA for vapor exposure or confined spaces
Water reactivity: Variable - some materials may react with water when hot, creating steam hazard from rapid cooling. Recommended extinguishing: Dry chemical, CO2, or foam appropriate for specific substance; avoid direct water application due to temperature differential and potential spattering.
ERG Guide 171 recommendation: ERG 171: Isolate spill area at least 25m in all directions; container rupture risk from cooling/heating cycles requires safe distance from fire exposure
No. This is a training/quick-reference aid only. Always consult the current ERG Guide 171 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.