☣️ UN 3134 • CLASS 4
Water-reactive solid, poisonous, n.o.s.
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 3134
Class: 4
Placard type: Dangerous When Wet
ERG: Guide 139 (check current ERG)
Isolation: ERG 139: Initial isolation 100m in all directions; protective action distance 300m downwind for small spills, 800m for large spills; increase distances for fire involvement
Chemical & Response Details
| Also known as | Water-reactive solid, toxic, n.o.s.Water-reactive poisonous solidDangerous when wet solid, toxicClass 4.3 toxic water-reactive solid |
| Appearance | Variable appearance depending on specific material; typically a solid powder, granules, or crystalline substance that may be white, gray, or colored. May emit toxic fumes or gases upon contact with moisture or water. |
| Flash Point | Not applicable (water-reactive solid; ignition occurs via water contact rather than conventional ignition) |
| Boiling Point | Not applicable (decomposes or reacts with water before boiling) |
| Vapor Density | Not applicable (solid material; toxic gases produced upon water contact will vary) |
| Water Reactivity | Reacts violently with water producing flammable and toxic gases; may ignite spontaneously on contact with water or moist air. DO NOT USE WATER. |
| Extinguishing | Dry chemical, dry sand, soda ash, lime; DO NOT use water, foam, or water-based agents |
| PPE | ⚠️ Level A or B minimum with SCBA required; full encapsulation if toxic gas release suspected; avoid contact with moisture |
| Isolation | ERG 139: Initial isolation 100m in all directions; protective action distance 300m downwind for small spills, 800m for large spills; increase distances for fire involvement |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Common hazards (high level)
- Produce flammable and toxic 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.
- Containers may explode when heated.
- Runoff may create fire or explosion hazard.
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
- 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 3134 — Water-reactive solid, poisonous, n.o.s. HAZMAT RADIO NOTE — UN 3134
Product: Water-reactive solid, poisonous, n.o.s.
Class 4 / Dangerous When Wet / ERG 139
PPE: Level A or B minimum with SCBA required; full encapsulation if toxic gas release suspected; avoid contact with moisture
ISOLATION: ERG 139: Initial isolation 100m in all directions; protective action distance 300m downwind for small spills, 800m for large spills; increase distances for fire involvement
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 3134 — Water-reactive solid, poisonous, n.o.s.
Class: 4 | Placard: Dangerous When Wet | ERG Guide: 139
Appearance: Variable appearance depending on specific material; typically a solid powder, granules, or crystalline substance that may be white, gray, or colored. May emit toxic fumes or gases upon contact with moisture or water.
Water Reactivity: Reacts violently with water producing flammable and toxic gases; may ignite spontaneously on contact with water or moist air. DO NOT USE WATER.
Extinguishing: Dry chemical, dry sand, soda ash, lime; DO NOT use water, foam, or water-based agents
PPE: Level A or B minimum with SCBA required; full encapsulation if toxic gas release suspected; avoid contact with moisture
Isolation: ERG 139: Initial isolation 100m in all directions; protective action distance 300m downwind for small spills, 800m for large spills; increase distances for fire involvement
— Key Hazards —
• Produce flammable and toxic 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/3134 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief. Full chemical + response details.
UN3134 Water-reactive solid, poisonous, n.o.s. Cls4 ERG139 | allfirefighter.com/hazmat/un/3134SMS / 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/3134
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FAQ
Produce flammable and toxic 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. Containers may explode when heated. Runoff may create fire or explosion hazard.
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 minimum with SCBA required; full encapsulation if toxic gas release suspected; avoid contact with moisture
No. This is a training/quick-reference aid only. Always consult the current ERG Guide 139 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.