☣️ UN 1476 • CLASS 5
Magnesium peroxide
Placard: Oxidizer. 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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Quick details
UN 1476
Class: 5
Placard type: Oxidizer
ERG: Guide 140 (check current ERG)
Isolation: ERG 140: isolate spill/leak 25m all directions; if large fire isolate 800m and consider evacuation
Chemical & Response Details
| Also known as | Magnesium dioxideMagnesium superoxidePeroxide of magnesiumMagnesium peroxide hydrate |
| CAS Number | 1335-26-8 |
| Appearance | White to off-white odorless powder or granular solid at room temperature. May appear yellowish when impure. |
| Flash Point | Not applicable (oxidizing solid, non-flammable but accelerates combustion) |
| Boiling Point | Not applicable (decomposes before boiling at approximately 100C/212F) |
| Vapor Density | Not applicable (solid material) |
| Water Reactivity | Reacts with water to release oxygen gas and form magnesium hydroxide; reaction is not violent but generates heat |
| Extinguishing | Dry chemical, dry sand, soda ash; do not use water or foam as oxidizer releases oxygen |
| PPE | ⚠️ Level C minimum with full face respirator; nitrile gloves; avoid skin/eye contact with dust |
| Isolation | ERG 140: isolate spill/leak 25m all directions; if large fire isolate 800m and consider evacuation |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Common hazards (high level)
- These substances will accelerate burning when involved in a fire.
- Some may decompose explosively when heated or involved in a fire.
- May explode from heat or contamination.
- Some will react explosively with hydrocarbons (fuels).
- May ignite combustibles (wood, paper, oil, clothing, etc.).
- Containers may explode when heated.
- Runoff may create fire or explosion hazard.
- Inhalation, ingestion or contact (skin, eyes) with vapors or substance may cause severe injury, burns or
First actions (field-minded)
- 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
- Consider initial downwind evacuation for at least 100 meters (330 feet).
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📋 Copy & Share
UN 1476 — Magnesium peroxide HAZMAT RADIO NOTE — UN 1476
Product: Magnesium peroxide
Class 5 / Oxidizer / ERG 140
PPE: Level C minimum with full face respirator; nitrile gloves; avoid skin/eye contact with dust
ISOLATION: ERG 140: isolate spill/leak 25m all directions; if large fire isolate 800m 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 1476 — Magnesium peroxide
Class: 5 | Placard: Oxidizer | ERG Guide: 140
Appearance: White to off-white odorless powder or granular solid at room temperature. May appear yellowish when impure.
Water Reactivity: Reacts with water to release oxygen gas and form magnesium hydroxide; reaction is not violent but generates heat
Extinguishing: Dry chemical, dry sand, soda ash; do not use water or foam as oxidizer releases oxygen
PPE: Level C minimum with full face respirator; nitrile gloves; avoid skin/eye contact with dust
Isolation: ERG 140: isolate spill/leak 25m all directions; if large fire isolate 800m and consider evacuation
— Key Hazards —
• These substances will accelerate burning when involved in a fire.
• Some may decompose explosively when heated or involved in a fire.
• May explode from heat or contamination.
— 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/1476 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief. Full chemical + response details.
UN1476 Magnesium peroxide Cls5 ERG140 | ERG 140: isolate spill/leak 25m all directions; if large fire isolate 800m and c | allfirefighter.com/hazmat/un/1476SMS / 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/1476
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FAQ
These substances will accelerate burning when involved in a fire. Some may decompose explosively when heated or involved in a fire. May explode from heat or contamination. Some will react explosively with hydrocarbons (fuels). May ignite combustibles (wood, paper, oil, clothing, etc.). Containers may explode when heated. Runoff may create fire or explosion hazard. Inhalation, ingestion or contact (skin, eyes) with vapors or substance may cause severe injury, burns or
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 C minimum with full face respirator; nitrile gloves; avoid skin/eye contact with dust
No. This is a training/quick-reference aid only. Always consult the current ERG Guide 140 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.