☣️ UN 1056 • CLASS 2

Krypton, compressed

Placard: Non-Flammable 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 1056
Class: 2
Placard type: Non-Flammable Gas
ERG: Guide 120 (check current ERG)
Isolation: ERG 120: isolate 100m in all directions initially; evacuate immediate area if large release; ventilate confined spaces
Chemical & Response Details
Also known asKrKrypton gasRefrigerated liquid kryptonCryogenic krypton
CAS Number7439-90-9
AppearanceColorless, odorless gas at room temperature. When compressed or liquefied, appears as a colorless cryogenic liquid. Heavier than air as a gas.
Flash PointNot applicable (inert gas)
Boiling Point-153C (-244F)
Vapor Density2.9 (heavier than air)
Water ReactivityNo reaction - inert noble gas
ExtinguishingNot applicable - use ventilation; inert gas requires no extinguishing agents
PPE⚠️ Level D for compressed gas releases; insulated gloves and face shield for cryogenic liquid contact; SCBA if oxygen deficiency suspected
IsolationERG 120: isolate 100m in all directions initially; evacuate immediate area if large release; ventilate confined spaces
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Common hazards (high level)
  • Vapors may cause dizziness or asphyxiation without warning, especially when in closed or confined areas.
  • Vapors from liquefied gas are initially heavier than air and spread along ground.
  • Contact with gas, liquefied gas or cryogenic liquids may cause burns, severe injury and/or frostbite.
  • Non-flammable gases.
  • Containers may explode when heated.
  • Ruptured cylinders may rocket.
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.
  • Consider initial downwind evacuation for at least 100 meters (330 feet).
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UN 1056 — Krypton, compressed
HAZMAT RADIO NOTE — UN 1056 Product: Krypton, compressed Class 2 / Non-Flammable Gas / ERG 120 PPE: Level D for compressed gas releases; insulated gloves and face shield for cryogenic liquid contact; SCBA if oxygen deficiency suspected ISOLATION: ERG 120: isolate 100m in all directions initially; evacuate immediate area if large release; ventilate confined spaces 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 1056 — Krypton, compressed Class: 2 | Placard: Non-Flammable Gas | ERG Guide: 120 Appearance: Colorless, odorless gas at room temperature. When compressed or liquefied, appears as a colorless cryogenic liquid. Heavier than air as a gas. Water Reactivity: No reaction - inert noble gas Extinguishing: Not applicable - use ventilation; inert gas requires no extinguishing agents PPE: Level D for compressed gas releases; insulated gloves and face shield for cryogenic liquid contact; SCBA if oxygen deficiency suspected Isolation: ERG 120: isolate 100m in all directions initially; evacuate immediate area if large release; ventilate confined spaces — Key Hazards — • Vapors may cause dizziness or asphyxiation without warning, especially when in closed or confined areas. • Vapors from liquefied gas are initially heavier than air and spread along ground. • Contact with gas, liquefied gas or cryogenic liquids 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/1056 | 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)
UN1056 Krypton, compressed Cls2 ERG120 | ERG 120: isolate 100m in all directions initially; evacuate immediate area if la | allfirefighter.com/hazmat/un/1056SMS / 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/1056
Related UN numbers (same class)
Discovery block for training / quick reference. Always consult the current ERG + your SOP/SOG for operations.
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FAQ

Vapors may cause dizziness or asphyxiation without warning, especially when in closed or confined areas. Vapors from liquefied gas are initially heavier than air and spread along ground. Contact with gas, liquefied gas or cryogenic liquids may cause burns, severe injury and/or frostbite. Non-flammable gases. Containers may explode when heated. Ruptured cylinders may rocket.

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 D for compressed gas releases; insulated gloves and face shield for cryogenic liquid contact; SCBA if oxygen deficiency suspected

No. This is a training/quick-reference aid only. Always consult the current ERG Guide 120 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.