☣️ UN 3306 • CLASS 2
UN 3306 — Compressed gas, poisonous, oxidizing, corrosive, n.o.s. (Inhalation Hazard Zone A)
Placard: Toxic Gas. ERG Guide 124. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
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⚠️ 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.
Compressed gas, poisonous, oxidizing, corrosive, n.o.s. (Inhalation Hazard Zone A) is a Zone A toxic gas entry with severe inhalation hazard. Releases require immediate isolation, air monitoring and specialized hazmat control.
Hazard overview: Toxic oxidizing corrosive gas may be fatal if inhaled and may also be corrosive, oxidizing or flammable depending on the exact gas. Vapors can spread along the ground and threaten downwind areas.
Response guidance: Use ERG Guide 124 and Table 1 distances, stay upwind, deny entry and evacuate downwind as directed. Do not attempt leak control without Level A protection and gas-specific monitoring.
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UN 3306 Quick Details
UN 3306
Product name: Compressed gas, poisonous, oxidizing, corrosive, n.o.s. (Inhalation Hazard Zone A)
DOT Class: 2
Placard type: Toxic Gas
ERG Guide: 124 (check current ERG)
Initial isolation: ERG 124: Isolate spill or leak area immediately for at least 800 meters (1/2 mile) in all directions; Inhalation Hazard Zone A requires large-scale evacuation; consider initial evacuation for 3 km (2 miles) downwind
Common Hazards of UN 3306
- TOXIC and/or CORROSIVE; may be fatal if inhaled or absorbed through skin.
- Fire will produce irritating, corrosive and/or toxic gases.
- Contact with gas or liquefied gas may cause burns, severe injury and/or frostbite.
- Runoff from fire control or dilution water may cause environmental contamination.
- Substance does not burn but will support combustion.
- Vapors from liquefied gas are initially heavier than air and spread along ground.
- These are strong oxidizers and will react vigorously or explosively with many materials including fuels.
- May ignite combustibles (wood, paper, oil, clothing, etc.).
Chemical Identity & Physical Properties
Compressed gas with multiple hazards including toxicity, oxidizing properties, and corrosivity. Physical state varies by specific chemical composition; may be colorless or have characteristic color depending on contents. Contact with liquefied gas can cause severe frostbite.
| Also known as | Compressed poisonous oxidizing corrosive gas n.o.s.Toxic oxidizing corrosive compressed gasPoisonous oxidizing corrosive gas NOSUN3306 compressed gas |
| Appearance | Compressed gas with multiple hazards including toxicity, oxidizing properties, and corrosivity. Physical state varies by specific chemical composition; may be colorless or have characteristic color depending on contents. Contact with liquefied gas can cause severe frostbite. |
| Flash Point | Not applicable (compressed gas) |
| Boiling Point | Not applicable (varies by specific gas composition) |
| Vapor Density | Varies by specific gas; typically heavier than air for toxic gases |
| Water Reactivity | May react violently with water due to corrosive nature; generates corrosive and toxic gases |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Fireground Response Guidance — UN 3306
Extinguishing Media
Do not use water or foam; use dry chemical or CO2 from a distance; evacuate area
PPE Requirements
⚠️ Level A required; full encapsulating suit with SCBA; chemical-resistant gloves and boots; no skin contact permitted due to corrosive and toxic nature
Level A required; full encapsulating suit with SCBA; chemical-resistant gloves and boots; no skin contact permitted due to corrosive and toxic nature.
Isolation & Evacuation
ERG 124: Isolate spill or leak area immediately for at least 800 meters (1/2 mile) in all directions; Inhalation Hazard Zone A requires large-scale evacuation; consider initial evacuation for 3 km (2 miles) downwind
Always confirm protective actions with the current edition of the Emergency Response Guidebook (ERG Guide 124).
First Actions for a UN 3306 Incident
- CALL 911, then contact the emergency response telephone number shown on shipping papers, if available.
- Keep unauthorized personnel away.
- Stay upwind, uphill and/or upstream.
- Many gases are heavier than air and will spread along the ground and collect in low or confined areas.
- Ventilate closed spaces before entering, but only if properly trained and equipped.
- Isolate spill or leak area for at least 100 meters (330 feet) in all directions.
- See Table 1 - Initial Isolation and Protective Action Distances.
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📋 Copy & Share Field Card
UN 3306 — Compressed gas, poisonous, oxidizing, coHAZMAT RADIO NOTE — UN 3306
Product: Compressed gas, poisonous, oxidizing, corrosive, n.o.s. (Inhalation Hazard Zone A)
Class 2 / Toxic Gas / ERG 124
PPE: Level A required; full encapsulating suit with SCBA; chemical-resistant gloves and boots; no skin contact permitted due to corrosive and toxic nature
ISOLATION: ERG 124: Isolate spill or leak area immediately for at least 800 meters (1/2 mile) in all directions; Inhalation Hazard Zone A requires large-scale evacuation; consider initial evacuation for 3 km (2 miles) downwind
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 3306 — Compressed gas, poisonous, oxidizing, corrosive, n.o.s. (Inhalation Hazard Zone A)
Class: 2 | Placard: Toxic Gas | ERG Guide: 124
Appearance: Compressed gas with multiple hazards including toxicity, oxidizing properties, and corrosivity. Physical state varies by specific chemical composition; may be colorless or have characteristic color depending on contents. Contact with liquefied gas can cause severe frostbite.
Water Reactivity: May react violently with water due to corrosive nature; generates corrosive and toxic gases
Extinguishing: Do not use water or foam; use dry chemical or CO2 from a distance; evacuate area
PPE: Level A required; full encapsulating suit with SCBA; chemical-resistant gloves and boots; no skin contact permitted due to corrosive and toxic nature
Isolation: ERG 124: Isolate spill or leak area immediately for at least 800 meters (1/2 mile) in all directions; Inhalation Hazard Zone A requires large-scale evacuation; consider initial evacuation for 3 km (2 miles) downwind
— Key Hazards —
• TOXIC and/or CORROSIVE; may be fatal if inhaled or absorbed through skin.
• Fire will produce irritating, corrosive and/or toxic gases.
• Contact with gas or liquefied gas may cause burns, severe injury and/or frostbite.
— First Actions —
• CALL 911, then contact the emergency response telephone number shown on shipping papers, if available.
• Keep unauthorized personnel away.
• Stay upwind, uphill and/or upstream.
• Many gases are heavier than air and will spread along the ground and collect in low or confined areas.
SOURCE: allfirefighter.com/hazmat/un/compressed-gas-poisonous-oxidizing-un-3306 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief.
UN3306 Compressed gas, poisonous, oxidizing, corrosive, n.o.s. (Inhalation Hazard Zone A) Cls2 ERG124 | allfirefighter.com/hazmat/un/compressed-gas-poisonous-oxidizing-un-3306SMS / 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/compressed-gas-poisonous-oxidizing-un-3306
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Frequently Asked Questions about UN 3306
UN 3306 is Compressed gas, poisonous, oxidizing, corrosive, n.o.s. (Inhalation Hazard Zone A), assigned to ERG Guide 124 and placarded as Toxic Gas.
Yes. Toxic oxidizing corrosive gas presents a serious toxic exposure hazard; avoid inhalation, ingestion, skin contact and contaminated runoff.
Yes, corrosive effects are possible. Avoid skin and eye contact and use chemical-resistant protection.
Gas can spread downwind, collect in low or confined areas, displace oxygen or create toxic exposure depending on the material.
Use caution. May react violently with water due to corrosive nature; generates corrosive and toxic gases
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.