☣️ UN 3308 • CLASS 2
UN 3308 — Liquefied gas, poisonous, corrosive, n.o.s. (Inhalation Hazard Zone A)
Placard: Toxic Gas. ERG Guide 125. 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.
Liquefied gas, poisonous, 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 corrosive liquefied 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 125 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 3308 Quick Details
UN 3308
Product name: Liquefied gas, poisonous, corrosive, n.o.s. (Inhalation Hazard Zone A)
DOT Class: 2
Placard type: Toxic Gas
ERG Guide: 125 (check current ERG)
Initial isolation: ERG 125: Initial isolation 800m all directions; protective action distance 3.7km downwind daytime, 8.0km downwind nighttime for large spills
Common Hazards of UN 3308
- TOXIC and/or CORROSIVE; may be fatal if inhaled, ingested or absorbed through skin.
- Vapors are extremely irritating and corrosive.
- Contact with gas or liquefied gas may cause burns, severe injury and/or frostbite.
- Fire will produce irritating, corrosive and/or toxic gases.
- Runoff from fire control or dilution water may cause environmental contamination.
- Some may burn but none ignite readily.
- Vapors from liquefied gas are initially heavier than air and spread along ground.
- Some of these materials may react violently with water.
Chemical Identity & Physical Properties
Liquefied gas under pressure with variable color and odor depending on specific composition. Extremely toxic and corrosive vapors; causes severe irritation and frostbite upon contact with liquid or gas.
| Also known as | Liquefied poisonous corrosive gas n.o.s.Toxic corrosive compressed gasPoisonous corrosive liquefied gasInhalation hazard zone A gas |
| Appearance | Liquefied gas under pressure with variable color and odor depending on specific composition. Extremely toxic and corrosive vapors; causes severe irritation and frostbite upon contact with liquid or gas. |
| Flash Point | Not applicable (compressed gas) |
| Boiling Point | Variable depending on specific gas composition; typically below room temperature as liquefied gas |
| Vapor Density | Heavier than air (Zone A designation indicates high vapor density) |
| Water Reactivity | May react with water depending on specific corrosive gas; assume reactive until identified |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Fireground Response Guidance — UN 3308
Extinguishing Media
Do not use water; use appropriate gas fire fighting techniques, allow fire to burn if safely possible
PPE Requirements
⚠️ Level A required; full encapsulating suit with SCBA; extreme inhalation hazard Zone A designation requires maximum respiratory protection
Level A required; full encapsulating suit with SCBA; extreme inhalation hazard Zone A designation requires maximum respiratory protection.
Isolation & Evacuation
ERG 125: Initial isolation 800m all directions; protective action distance 3.7km downwind daytime, 8.0km downwind nighttime for large spills
Always confirm protective actions with the current edition of the Emergency Response Guidebook (ERG Guide 125).
First Actions for a UN 3308 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.
- For highlighted materials: see Table 1 - Initial Isolation and Protective Action Distances.
- For non-highlighted materials, increase downwind protective distance based on conditions and incident command guidance.
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📋 Copy & Share Field Card
UN 3308 — Liquefied gas, poisonous, corrosive, n.oHAZMAT RADIO NOTE — UN 3308
Product: Liquefied gas, poisonous, corrosive, n.o.s. (Inhalation Hazard Zone A)
Class 2 / Toxic Gas / ERG 125
PPE: Level A required; full encapsulating suit with SCBA; extreme inhalation hazard Zone A designation requires maximum respiratory protection
ISOLATION: ERG 125: Initial isolation 800m all directions; protective action distance 3.7km downwind daytime, 8.0km downwind nighttime for large spills
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 3308 — Liquefied gas, poisonous, corrosive, n.o.s. (Inhalation Hazard Zone A)
Class: 2 | Placard: Toxic Gas | ERG Guide: 125
Appearance: Liquefied gas under pressure with variable color and odor depending on specific composition. Extremely toxic and corrosive vapors; causes severe irritation and frostbite upon contact with liquid or gas.
Water Reactivity: May react with water depending on specific corrosive gas; assume reactive until identified
Extinguishing: Do not use water; use appropriate gas fire fighting techniques, allow fire to burn if safely possible
PPE: Level A required; full encapsulating suit with SCBA; extreme inhalation hazard Zone A designation requires maximum respiratory protection
Isolation: ERG 125: Initial isolation 800m all directions; protective action distance 3.7km downwind daytime, 8.0km downwind nighttime for large spills
— Key Hazards —
• TOXIC and/or CORROSIVE; may be fatal if inhaled, ingested or absorbed through skin.
• Vapors are extremely irritating and corrosive.
• 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/liquefied-gas-poisonous-corrosive-un-3308 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief.
UN3308 Liquefied gas, poisonous, corrosive, n.o.s. (Inhalation Hazard Zone A) Cls2 ERG125 | allfirefighter.com/hazmat/un/liquefied-gas-poisonous-corrosive-un-3308SMS / 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/liquefied-gas-poisonous-corrosive-un-3308
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Frequently Asked Questions about UN 3308
UN 3308 is Liquefied gas, poisonous, corrosive, n.o.s. (Inhalation Hazard Zone A), assigned to ERG Guide 125 and placarded as Toxic Gas.
Yes. Toxic corrosive liquefied 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 with water depending on specific corrosive gas; assume reactive until identified
Do not use water; use appropriate gas fire fighting techniques, allow fire to burn if safely possible.
Level A required; full encapsulating suit with SCBA; extreme inhalation hazard Zone A designation requires maximum respiratory protection.
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.