☣️ UN 3168 • CLASS 2
UN 3168 — Gas sample, non-pressurized, poisonous, flammable, n.o.s., not refrigerated liquid
Placard: Toxic Gas. ERG Guide 119. 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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UN 3168 Quick Details
UN 3168
Product name: Gas sample, non-pressurized, poisonous, flammable, n.o.s., not refrigerated liquid
DOT Class: 2
Placard type: Toxic Gas
ERG Guide: 119 (check current ERG)
Initial isolation: ERG 119: isolate spill/leak area immediately for at least 100m in all directions; evacuate initial 800m downwind if fire or large spill
Common Hazards of UN 3168
- TOXIC; may be fatal if inhaled or absorbed through skin. Some may cause severe skin burns and
- 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.
- Flammable; may be ignited by heat, sparks or flames.
- May form explosive mixtures with air. Ethylene oxide (UN1040) may react explosively even in the
- Those substances designated with a (P) may polymerize explosively when heated or involved in a fire.
- Vapors from liquefied gas are initially heavier than air and spread along ground.
Chemical Identity & Physical Properties
| Also known as | Non-pressurized poisonous flammable gas sampleToxic flammable gas sample NOSPoisonous flammable gas sample not under pressure |
| Appearance | Variable appearance depending on specific gas sampled; may be colorless to colored gas or liquefied gas at ambient or reduced pressure. Odor varies by composition. |
| Flash Point | Not applicable (gas sample) |
| Boiling Point | Variable depending on specific gas composition |
| Vapor Density | Typically heavier than air (specific gravity varies by gas composition) |
| Water Reactivity | Generally no significant reaction with water, though specific gases may vary |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Fireground Response Guidance — UN 3168
Extinguishing Media
Dry chemical, CO2, water spray for cooling containers; foam generally not effective on gas fires
PPE Requirements
⚠️ Level A or B required; full-face SCBA mandatory; chemical-resistant suit; avoid all contact due to toxic and flammable hazards
Isolation & Evacuation
ERG 119: isolate spill/leak area immediately for at least 100m in all directions; evacuate initial 800m downwind if fire or large spill
Always confirm protective actions with the current edition of the Emergency Response Guidebook (ERG Guide 119).
First Actions for a UN 3168 Incident
- 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.
- For highlighted materials: see Table 1 - Initial Isolation and Protective Action Distances.
- For non-highlighted materials: increase the immediate precautionary measure distance, in the downwind
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UN 3168 — Gas sample, non-pressurized, poisonous,HAZMAT RADIO NOTE — UN 3168
Product: Gas sample, non-pressurized, poisonous, flammable, n.o.s., not refrigerated liquid
Class 2 / Toxic Gas / ERG 119
PPE: Level A or B required; full-face SCBA mandatory; chemical-resistant suit; avoid all contact due to toxic and flammable hazards
ISOLATION: ERG 119: isolate spill/leak area immediately for at least 100m in all directions; evacuate initial 800m downwind if fire or large spill
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 3168 — Gas sample, non-pressurized, poisonous, flammable, n.o.s., not refrigerated liquid
Class: 2 | Placard: Toxic Gas | ERG Guide: 119
Appearance: Variable appearance depending on specific gas sampled; may be colorless to colored gas or liquefied gas at ambient or reduced pressure. Odor varies by composition.
Water Reactivity: Generally no significant reaction with water, though specific gases may vary
Extinguishing: Dry chemical, CO2, water spray for cooling containers; foam generally not effective on gas fires
PPE: Level A or B required; full-face SCBA mandatory; chemical-resistant suit; avoid all contact due to toxic and flammable hazards
Isolation: ERG 119: isolate spill/leak area immediately for at least 100m in all directions; evacuate initial 800m downwind if fire or large spill
— Key Hazards —
• TOXIC; may be fatal if inhaled or absorbed through skin. Some may cause severe skin burns and
• Contact with gas or liquefied gas may cause burns, severe injury and/or frostbite.
• Fire will produce irritating, corrosive and/or toxic gases.
— 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/3168 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief. Full chemical + response details.
UN3168 Gas sample, non-pressurized, poisonous, flammable, n.o.s., not refrigerated liquid Cls2 ERG119 | allfirefighter.com/hazmat/un/3168SMS / 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/3168
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Frequently Asked Questions about UN 3168
TOXIC; may be fatal if inhaled or absorbed through skin. Some may cause severe skin burns and 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. Flammable; may be ignited by heat, sparks or flames. May form explosive mixtures with air. Ethylene oxide (UN1040) may react explosively even in the Those substances designated with a (P) may polymerize explosively when heated or involved in a fire. Vapors from liquefied gas are initially heavier than air and spread along ground.
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 or B required; full-face SCBA mandatory; chemical-resistant suit; avoid all contact due to toxic and flammable hazards
Water reactivity: Generally no significant reaction with water, though specific gases may vary. Recommended extinguishing: Dry chemical, CO2, water spray for cooling containers; foam generally not effective on gas fires.
ERG Guide 119 recommendation: ERG 119: isolate spill/leak area immediately for at least 100m in all directions; evacuate initial 800m downwind if fire or large spill
No. This is a training/quick-reference aid only. Always consult the current ERG Guide 119 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.