☣️ UN 1422 • CLASS 4
Potassium sodium alloys, liquid
Placard: Dangerous When Wet. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
🚒☣️
⚠️ 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 1422
Class: 4
Placard type: Dangerous When Wet
ERG: Guide 138 (check current ERG)
Isolation: ERG 138: Initial isolation 150m in all directions. Protective action distance: large spill 800m daytime, 2500m nighttime. If tank/rail car involved in fire, isolate 1600m and consider evacuation.
Chemical & Response Details
| Also known as | NaKSodium-potassium alloyK-Na alloyNaK eutecticLiquid metal coolant |
| Appearance | Silvery metallic liquid at room temperature with a characteristic metallic luster. Typically appears as a dense, mobile liquid that may develop a gray oxide coating upon air exposure. |
| Flash Point | Not applicable (pyrophoric - ignites spontaneously in air) |
| Boiling Point | Varies with composition, typically 785-825C (1445-1517F) |
| Vapor Density | Not applicable (liquid metal at room temperature) |
| Water Reactivity | Reacts violently and explosively with water, producing flammable hydrogen gas and heat. May ignite spontaneously. Never use water for firefighting or spills. |
| Extinguishing | Metal fire powder (G-1, pyrene, TEC), dry sand, dry graphite. DO NOT USE water, foam, CO2, or halogenated agents. |
| PPE | ⚠️ Level A required during response. Full vapor-tight encapsulating suit, SCBA, chemical-resistant gloves. Face shield and thermal protection for fire exposure. Keep all moisture away. |
| Isolation | ERG 138: Initial isolation 150m in all directions. Protective action distance: large spill 800m daytime, 2500m nighttime. If tank/rail car involved in fire, isolate 1600m and consider evacuation. |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Common hazards (high level)
- Produce flammable gases on contact with water.
- May ignite on contact with water or moist air.
- Some react vigorously or explosively on contact with water.
- May be ignited by heat, sparks or flames.
- May re-ignite after fire is extinguished.
- Some are transported in highly flammable liquids.
- Runoff may create fire or explosion hazard.
- Inhalation or contact with vapors, substance or decomposition products may cause severe injury or
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.
- Ventilate closed spaces before entering, but only if properly trained and equipped.
- Isolate spill or leak area in all directions for at least 50 meters (150 feet) for liquids and at least 25 meters
- Consider initial downwind evacuation for at least 300 meters (1000 feet).
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UN 1422 — Potassium sodium alloys, liquid HAZMAT RADIO NOTE — UN 1422
Product: Potassium sodium alloys, liquid
Class 4 / Dangerous When Wet / ERG 138
PPE: Level A required during response. Full vapor-tight encapsulating suit, SCBA, chemical-resistant gloves. Face shield and thermal protection for fire exposure. Keep all moisture away.
ISOLATION: ERG 138: Initial isolation 150m in all directions. Protective action distance: large spill 800m daytime, 2500m nighttime. If tank/rail car involved in fire, isolate 1600m and consider evacuation.
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 1422 — Potassium sodium alloys, liquid
Class: 4 | Placard: Dangerous When Wet | ERG Guide: 138
Appearance: Silvery metallic liquid at room temperature with a characteristic metallic luster. Typically appears as a dense, mobile liquid that may develop a gray oxide coating upon air exposure.
Water Reactivity: Reacts violently and explosively with water, producing flammable hydrogen gas and heat. May ignite spontaneously. Never use water for firefighting or spills.
Extinguishing: Metal fire powder (G-1, pyrene, TEC), dry sand, dry graphite. DO NOT USE water, foam, CO2, or halogenated agents.
PPE: Level A required during response. Full vapor-tight encapsulating suit, SCBA, chemical-resistant gloves. Face shield and thermal protection for fire exposure. Keep all moisture away.
Isolation: ERG 138: Initial isolation 150m in all directions. Protective action distance: large spill 800m daytime, 2500m nighttime. If tank/rail car involved in fire, isolate 1600m and consider evacuation.
— Key Hazards —
• Produce flammable gases on contact with water.
• May ignite on contact with water or moist air.
• Some react vigorously or explosively on contact with water.
— 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.
• Ventilate closed spaces before entering, but only if properly trained and equipped.
SOURCE: allfirefighter.com/hazmat/un/1422 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief. Full chemical + response details.
UN1422 Potassium sodium alloys, liquid Cls4 ERG138 | allfirefighter.com/hazmat/un/1422SMS / 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/1422
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FAQ
Produce flammable gases on contact with water. May ignite on contact with water or moist air. Some react vigorously or explosively on contact with water. May be ignited by heat, sparks or flames. May re-ignite after fire is extinguished. Some are transported in highly flammable liquids. Runoff may create fire or explosion hazard. Inhalation or contact with vapors, substance or decomposition products may cause severe injury or
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 during response. Full vapor-tight encapsulating suit, SCBA, chemical-resistant gloves. Face shield and thermal protection for fire exposure. Keep all moisture away.
No. This is a training/quick-reference aid only. Always consult the current ERG Guide 138 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.