☣️ UN 1389 • CLASS 4
Alkali metal amalgam, liquid
Placard: Dangerous When Wet. 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 1389
Class: 4
Placard type: Dangerous When Wet
ERG: Guide 138 (check current ERG)
Isolation: ERG 138: isolate spill area minimum 25m all directions. If fire or water contact, isolate 800m and consider evacuation 1600m downwind.
Chemical & Response Details
| Also known as | Sodium amalgam liquidPotassium amalgam liquidMercury-alkali metal alloyLiquid metal amalgam |
| Appearance | Silvery liquid metal alloy consisting of mercury combined with alkali metals (sodium, potassium, etc.). Dense, mobile liquid at room temperature with metallic luster. |
| Flash Point | Not applicable (reactive metal) |
| Boiling Point | Varies by composition, mercury component boils at 357C (675F) |
| Vapor Density | Not applicable (liquid metal, mercury vapor heavier than air) |
| Water Reactivity | Reacts violently with water producing flammable hydrogen gas and heat; may ignite spontaneously. Keep away from moisture and water. |
| Extinguishing | Dry sand, dry chemical, soda ash. DO NOT use water, foam, or CO2. Use dry graphite powder or approved Class D extinguishing agents. |
| PPE | ⚠️ Level A or B required; SCBA mandatory. Full chemical-resistant suit, neoprene or butyl rubber gloves. Protect against mercury vapor exposure. |
| Isolation | ERG 138: isolate spill area minimum 25m all directions. If fire or water contact, isolate 800m and consider evacuation 1600m downwind. |
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 1389 — Alkali metal amalgam, liquid HAZMAT RADIO NOTE — UN 1389
Product: Alkali metal amalgam, liquid
Class 4 / Dangerous When Wet / ERG 138
PPE: Level A or B required; SCBA mandatory. Full chemical-resistant suit, neoprene or butyl rubber gloves. Protect against mercury vapor exposure.
ISOLATION: ERG 138: isolate spill area minimum 25m all directions. If fire or water contact, isolate 800m and consider evacuation 1600m downwind.
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 1389 — Alkali metal amalgam, liquid
Class: 4 | Placard: Dangerous When Wet | ERG Guide: 138
Appearance: Silvery liquid metal alloy consisting of mercury combined with alkali metals (sodium, potassium, etc.). Dense, mobile liquid at room temperature with metallic luster.
Water Reactivity: Reacts violently with water producing flammable hydrogen gas and heat; may ignite spontaneously. Keep away from moisture and water.
Extinguishing: Dry sand, dry chemical, soda ash. DO NOT use water, foam, or CO2. Use dry graphite powder or approved Class D extinguishing agents.
PPE: Level A or B required; SCBA mandatory. Full chemical-resistant suit, neoprene or butyl rubber gloves. Protect against mercury vapor exposure.
Isolation: ERG 138: isolate spill area minimum 25m all directions. If fire or water contact, isolate 800m and consider evacuation 1600m downwind.
— 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/1389 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief. Full chemical + response details.
UN1389 Alkali metal amalgam, liquid Cls4 ERG138 | allfirefighter.com/hazmat/un/1389SMS / 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/1389
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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 or B required; SCBA mandatory. Full chemical-resistant suit, neoprene or butyl rubber gloves. Protect against mercury vapor exposure.
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.