☣️ UN 1491 • CLASS 5
UN 1491 — Potassium peroxide
Placard: Oxidizer. ERG Guide 144. 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 1491 Quick Details
UN 1491
Product name: Potassium peroxide
DOT Class: 5
Placard type: Oxidizer
ERG Guide: 144 (check current ERG)
Initial isolation: ERG 144: isolate spill/leak 50m all directions; large spill 100m; fire: evacuate 800m radius
Common Hazards of UN 1491
- May ignite combustibles (wood, paper, oil, clothing, etc.).
- React vigorously and/or explosively with water.
- Produce toxic and/or corrosive substances on contact with water.
- Flammable/toxic gases may accumulate in tanks and hopper cars.
- Some may produce flammable hydrogen gas upon contact with metals.
- Containers may explode when heated.
- Runoff may create fire or explosion hazard.
- TOXIC; inhalation or contact with vapor, substance, or decomposition products may cause severe injury
Chemical Identity & Physical Properties
| Also known as | Potassium dioxideDipotassium peroxidePotassium superoxide (historical)Peroxide of potassium |
| CAS Number | 17014-71-0 |
| Appearance | Yellow to orange-yellow granular solid or powder. Odorless. Hygroscopic and highly reactive oxidizer. |
| Flash Point | Not applicable (oxidizing solid) |
| Boiling Point | Decomposes at approximately 490C (914F) |
| Vapor Density | Not applicable (solid) |
| Water Reactivity | Reacts violently with water, releasing oxygen and heat, forming corrosive potassium hydroxide solution |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Fireground Response Guidance — UN 1491
Extinguishing Media
Dry chemical, dry sand, soda ash; NO WATER OR FOAM
PPE Requirements
⚠️ Level A or B minimum; full-face SCBA required; chemical-resistant suit; avoid all contact
Isolation & Evacuation
ERG 144: isolate spill/leak 50m all directions; large spill 100m; fire: evacuate 800m radius
Always confirm protective actions with the current edition of the Emergency Response Guidebook (ERG Guide 144).
First Actions for a UN 1491 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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📋 Copy & Share Field Card
UN 1491 — Potassium peroxideHAZMAT RADIO NOTE — UN 1491
Product: Potassium peroxide
Class 5 / Oxidizer / ERG 144
PPE: Level A or B minimum; full-face SCBA required; chemical-resistant suit; avoid all contact
ISOLATION: ERG 144: isolate spill/leak 50m all directions; large spill 100m; fire: evacuate 800m radius
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 1491 — Potassium peroxide
Class: 5 | Placard: Oxidizer | ERG Guide: 144
Appearance: Yellow to orange-yellow granular solid or powder. Odorless. Hygroscopic and highly reactive oxidizer.
Water Reactivity: Reacts violently with water, releasing oxygen and heat, forming corrosive potassium hydroxide solution
Extinguishing: Dry chemical, dry sand, soda ash; NO WATER OR FOAM
PPE: Level A or B minimum; full-face SCBA required; chemical-resistant suit; avoid all contact
Isolation: ERG 144: isolate spill/leak 50m all directions; large spill 100m; fire: evacuate 800m radius
— Key Hazards —
• May ignite combustibles (wood, paper, oil, clothing, etc.).
• React vigorously and/or explosively with water.
• Produce toxic and/or corrosive substances on contact with water.
— 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/1491 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief. Full chemical + response details.
UN1491 Potassium peroxide Cls5 ERG144 | ERG 144: isolate spill/leak 50m all directions; large spill 100m; fire: evacuate | allfirefighter.com/hazmat/un/1491SMS / 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/1491
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Frequently Asked Questions about UN 1491
May ignite combustibles (wood, paper, oil, clothing, etc.). React vigorously and/or explosively with water. Produce toxic and/or corrosive substances on contact with water. Flammable/toxic gases may accumulate in tanks and hopper cars. Some may produce flammable hydrogen gas upon contact with metals. Containers may explode when heated. Runoff may create fire or explosion hazard. TOXIC; inhalation or contact with vapor, substance, or decomposition products may cause severe injury
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 A or B minimum; full-face SCBA required; chemical-resistant suit; avoid all contact
Water reactivity: Reacts violently with water, releasing oxygen and heat, forming corrosive potassium hydroxide solution. Recommended extinguishing: Dry chemical, dry sand, soda ash; NO WATER OR FOAM.
ERG Guide 144 recommendation: ERG 144: isolate spill/leak 50m all directions; large spill 100m; fire: evacuate 800m radius
No. This is a training/quick-reference aid only. Always consult the current ERG Guide 144 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.