☣️ UN 3306 • CLASS 2
Compressed gas, poisonous, oxidizing, corrosive, n.o.s. (Inhalation Hazard Zone A)
Placard: Toxic Gas. 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 3306
Class: 2
Placard type: Toxic Gas
ERG: Guide 124 (check current ERG)
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
Chemical & Response Details
| 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 |
| 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 |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Common hazards (high level)
- 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.).
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.
- 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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UN 3306 — Compressed gas, poisonous, oxidizing, co HAZMAT 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 call emergency response telephone number on shipping paper. If shipping paper
• 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/3306 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief. Full chemical + response details.
UN3306 Compressed gas, poisonous, oxidizing, corrosive, n.o.s. (Inhalation Hazard Zone A) Cls2 ERG124 | allfirefighter.com/hazmat/un/3306SMS / 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/3306
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FAQ
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.).
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 required; full encapsulating suit with SCBA; chemical-resistant gloves and boots; no skin contact permitted due to corrosive and toxic nature
No. This is a training/quick-reference aid only. Always consult the current ERG Guide 124 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.