☣️ UN 1953 • CLASS 2

UN 1953 — Compressed gas, poisonous, flammable, n.o.s. (Inhalation Hazard Zone A)

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 1953 Quick Details

UN 1953
Product name: Compressed gas, poisonous, flammable, n.o.s. (Inhalation Hazard Zone A)
DOT Class: 2
Placard type: Toxic Gas
ERG Guide: 119 (check current ERG)
Initial isolation: ERG 119: isolate spill/leak area immediately 100m in all directions; if tank/rail car involved in fire, isolate 800m all directions and consider initial evacuation 800m

Common Hazards of UN 1953

  • 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 asPoisonous compressed gas n.o.s.Toxic flammable gas n.o.s.Compressed toxic flammable gasInhalation hazard gas Zone A
AppearanceGeneric classification for compressed gases that are both poisonous and flammable. Physical state is gas under pressure; may be liquefied. Color and odor vary depending on specific gas composition.
Flash PointNot applicable (flammable gas)
Boiling PointNot applicable (varies by specific gas composition)
Vapor DensityVaries by composition (typically heavier than air for Zone A materials)
Water ReactivityVaries by specific gas; some may react, others inert with water
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.

Fireground Response Guidance — UN 1953

Extinguishing Media

Do not use water or foam; use dry chemical or CO2 if appropriate for specific gas

PPE Requirements

⚠️ Level A required; SCBA with full face positive pressure; chemical-resistant suit; contact may cause frostbite and severe burns

Isolation & Evacuation

ERG 119: isolate spill/leak area immediately 100m in all directions; if tank/rail car involved in fire, isolate 800m all directions and consider initial evacuation 800m
Always confirm protective actions with the current edition of the Emergency Response Guidebook (ERG Guide 119).

First Actions for a UN 1953 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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📋 Copy & Share Field Card

UN 1953 — Compressed gas, poisonous, flammable, n.
HAZMAT RADIO NOTE — UN 1953 Product: Compressed gas, poisonous, flammable, n.o.s. (Inhalation Hazard Zone A) Class 2 / Toxic Gas / ERG 119 PPE: Level A required; SCBA with full face positive pressure; chemical-resistant suit; contact may cause frostbite and severe burns ISOLATION: ERG 119: isolate spill/leak area immediately 100m in all directions; if tank/rail car involved in fire, isolate 800m all directions and consider initial evacuation 800m ACTION: Stage upwind · Isolate · Deny entry · Request HazmatRADIO

Use for: Quick radio or face-to-face size-up. Short, structured, field-ready.

SMS WhatsApp
=== IC HAZMAT BRIEFING === UN 1953 — Compressed gas, poisonous, flammable, n.o.s. (Inhalation Hazard Zone A) Class: 2 | Placard: Toxic Gas | ERG Guide: 119 Appearance: Generic classification for compressed gases that are both poisonous and flammable. Physical state is gas under pressure; may be liquefied. Color and odor vary depending on specific gas composition. Water Reactivity: Varies by specific gas; some may react, others inert with water Extinguishing: Do not use water or foam; use dry chemical or CO2 if appropriate for specific gas PPE: Level A required; SCBA with full face positive pressure; chemical-resistant suit; contact may cause frostbite and severe burns Isolation: ERG 119: isolate spill/leak area immediately 100m in all directions; if tank/rail car involved in fire, isolate 800m all directions and consider initial evacuation 800m — 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/1953 | Always use current ERG + SOP/SOGIC BRIEFING

Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief. Full chemical + response details.

SMS (short)
UN1953 Compressed gas, poisonous, flammable, n.o.s. (Inhalation Hazard Zone A) Cls2 ERG119 | allfirefighter.com/hazmat/un/1953SMS / 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/1953

Related UN Numbers in Class 2

Discovery block for training / quick reference. Always consult the current ERG + your SOP/SOG for operations.
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Frequently Asked Questions about UN 1953

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 required; SCBA with full face positive pressure; chemical-resistant suit; contact may cause frostbite and severe burns

Water reactivity: Varies by specific gas; some may react, others inert with water. Recommended extinguishing: Do not use water or foam; use dry chemical or CO2 if appropriate for specific gas.

ERG Guide 119 recommendation: ERG 119: isolate spill/leak area immediately 100m in all directions; if tank/rail car involved in fire, isolate 800m all directions and consider initial evacuation 800m

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.