☣️ UN 3356 • CLASS 5
UN 3356 — Oxygen generator, chemical, spent
Placard: Oxidizer. ERG Guide 140. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
🚒☣️
⚠️ Verification required:
Broad or variable material category; verify exact product, SDS and shipping papers.
⚠️ 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.
Spent chemical oxygen generators may still contain residual oxidizing material or hot reaction byproducts inside a canister.
Hazard overview: Residual chlorates or oxidizers can intensify fire, react with combustibles and create pressure or explosion hazards if heated.
Response guidance: Keep units away from fuels and organic material. Cool exposed containers from a distance and avoid handling hot, damaged or leaking canisters.
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UN 3356 Quick Details
UN 3356
Product name: Oxygen generator, chemical, spent
DOT Class: 5
Placard type: Oxidizer
ERG Guide: 140 (check current ERG)
Initial isolation: ERG 140: isolate spill area 25m in all directions; if fire or explosion risk, isolate 800m and consider evacuation of 800m radius
Common Hazards of UN 3356
- 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 with vapors or substance may cause severe injury, burns or poisoning.
Chemical Identity & Physical Properties
Solid metal canister or cartridge containing residual oxidizing chemicals (typically chlorate salts) and reaction byproducts. May appear as a cylindrical unit with darkened or discolored interior.
| Also known as | Spent oxygen canisterChlorate candle (spent)Oxygen candle (spent)Chemical oxygen generator |
| Appearance | Solid metal canister or cartridge containing residual oxidizing chemicals (typically chlorate salts) and reaction byproducts. May appear as a cylindrical unit with darkened or discolored interior. |
| Flash Point | Not applicable (oxidizing solid) |
| Boiling Point | Not applicable (solid mixture) |
| Vapor Density | Not applicable (solid) |
| Water Reactivity | May react with water if residual chlorates present; avoid direct water contact on hot or damaged units |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Fireground Response Guidance — UN 3356
Extinguishing Media
Use water spray from distance, dry sand, or dry chemical; do not apply foam directly to hot units
PPE Requirements
⚠️ Level B minimum; SCBA required; thermal-protective clothing if units are hot; avoid inhalation of decomposition products
Use SCBA, eye protection and thermal protective clothing when units are hot, damaged or involved in fire.
Isolation & Evacuation
ERG 140: isolate spill area 25m in all directions; if fire or explosion risk, isolate 800m and consider evacuation of 800m radius
Always confirm protective actions with the current edition of the Emergency Response Guidebook (ERG Guide 140).
First Actions for a UN 3356 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 the spill or leak area in all directions; use the ERG guide and shipping papers to set exact distances.
- Consider initial downwind evacuation for at least 100 meters (330 feet).
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📋 Copy & Share Field Card
UN 3356 — Oxygen generator, chemical, spentHAZMAT RADIO NOTE — UN 3356
Product: Oxygen generator, chemical, spent
Class 5 / Oxidizer / ERG 140
PPE: Level B minimum; SCBA required; thermal-protective clothing if units are hot; avoid inhalation of decomposition products
ISOLATION: ERG 140: isolate spill area 25m in all directions; if fire or explosion risk, isolate 800m and consider evacuation of 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 3356 — Oxygen generator, chemical, spent
Class: 5 | Placard: Oxidizer | ERG Guide: 140
Appearance: Solid metal canister or cartridge containing residual oxidizing chemicals (typically chlorate salts) and reaction byproducts. May appear as a cylindrical unit with darkened or discolored interior.
Water Reactivity: May react with water if residual chlorates present; avoid direct water contact on hot or damaged units
Extinguishing: Use water spray from distance, dry sand, or dry chemical; do not apply foam directly to hot units
PPE: Level B minimum; SCBA required; thermal-protective clothing if units are hot; avoid inhalation of decomposition products
Isolation: ERG 140: isolate spill area 25m in all directions; if fire or explosion risk, isolate 800m and consider evacuation of 800m radius
— 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 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.
SOURCE: allfirefighter.com/hazmat/un/oxygen-generator-chemical-spent-un-3356 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief.
UN3356 Oxygen generator, chemical, spent Cls5 ERG140 | allfirefighter.com/hazmat/un/oxygen-generator-chemical-spent-un-3356SMS / 160 CHAR
Use for: Quick text to command or incoming units. Fits in a single SMS.
⚠️ Quick-reference only. Always use current ERG + SOP/SOG for incident-specific actions.
Page: https://allfirefighter.com/hazmat/un/oxygen-generator-chemical-spent-un-3356
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Frequently Asked Questions about UN 3356
UN 3356 is the entry for spent chemical oxygen generators.
Yes. Residual oxidizing chemicals may remain even after use.
The material can accelerate burning and may decompose if heated or contaminated.
Use water spray from a distance for cooling or dry agents as directed by incident command.
SCBA and protective clothing are needed for fire, heat or damaged canisters.
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.