☣️ UN 3121 • CLASS 5
Oxidizing solid, water-reactive, n.o.s.
Placard: Oxidizer. 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.
Advertisement
Quick details
UN 3121
Class: 5
Placard type: Oxidizer
ERG: Guide 144 (check current ERG)
Isolation: ERG 144: Isolate spill area immediately for at least 50 meters in all directions. Keep unauthorized personnel away. Evacuate area if fire involves this material or if exposed to heat.
Chemical & Response Details
| Also known as | Oxidizing solid water-reactive NOSWater-reactive oxidizing materialOxidizer with water reactivity |
| Appearance | Solid material at room temperature, typically appears as powder, granules, or crystals. Color and odor vary depending on specific substance, as this is a generic n.o.s. (not otherwise specified) classification. |
| Flash Point | Not applicable (oxidizing solid) |
| Boiling Point | Not applicable (decomposes or reacts) |
| Vapor Density | Not applicable (solid) |
| Water Reactivity | Reacts vigorously and/or explosively with water, producing toxic and/or corrosive substances. Do not use water for firefighting or cleanup. |
| Extinguishing | Dry chemical, dry sand, or dry earth only. Do not use water, foam, or CO2. Smother with dry materials. |
| PPE | ⚠️ Level B minimum with SCBA required. Full face respiratory protection and chemical-resistant suit. Avoid all contact with moisture. |
| Isolation | ERG 144: Isolate spill area immediately for at least 50 meters in all directions. Keep unauthorized personnel away. Evacuate area if fire involves this material or if exposed to heat. |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Common hazards (high level)
- May ignite combustibles (wood, paper, oil, clothing, etc.).
- React vigorously and/or explosively with water.
- Produce toxic and/or corrosive substances on contact with water.
- Flammable/toxic gases may accumulate in tanks and hopper cars.
- Some may produce flammable hydrogen gas upon contact with metals.
- Containers may explode when heated.
- Runoff may create fire or explosion hazard.
- TOXIC; inhalation or contact with vapor, substance, or decomposition products may cause severe injury
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
Advertisement
📋 Copy & Share
UN 3121 — Oxidizing solid, water-reactive, n.o.s. HAZMAT RADIO NOTE — UN 3121
Product: Oxidizing solid, water-reactive, n.o.s.
Class 5 / Oxidizer / ERG 144
PPE: Level B minimum with SCBA required. Full face respiratory protection and chemical-resistant suit. Avoid all contact with moisture.
ISOLATION: ERG 144: Isolate spill area immediately for at least 50 meters in all directions. Keep unauthorized personnel away. Evacuate area if fire involves this material or if exposed to heat.
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 3121 — Oxidizing solid, water-reactive, n.o.s.
Class: 5 | Placard: Oxidizer | ERG Guide: 144
Appearance: Solid material at room temperature, typically appears as powder, granules, or crystals. Color and odor vary depending on specific substance, as this is a generic n.o.s. (not otherwise specified) classification.
Water Reactivity: Reacts vigorously and/or explosively with water, producing toxic and/or corrosive substances. Do not use water for firefighting or cleanup.
Extinguishing: Dry chemical, dry sand, or dry earth only. Do not use water, foam, or CO2. Smother with dry materials.
PPE: Level B minimum with SCBA required. Full face respiratory protection and chemical-resistant suit. Avoid all contact with moisture.
Isolation: ERG 144: Isolate spill area immediately for at least 50 meters in all directions. Keep unauthorized personnel away. Evacuate area if fire involves this material or if exposed to heat.
— Key Hazards —
• May ignite combustibles (wood, paper, oil, clothing, etc.).
• React vigorously and/or explosively with water.
• Produce toxic and/or corrosive substances 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/3121 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief. Full chemical + response details.
UN3121 Oxidizing solid, water-reactive, n.o.s. Cls5 ERG144 | allfirefighter.com/hazmat/un/3121SMS / 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/3121
Advertisement
FAQ
May ignite combustibles (wood, paper, oil, clothing, etc.). React vigorously and/or explosively with water. Produce toxic and/or corrosive substances on contact with water. Flammable/toxic gases may accumulate in tanks and hopper cars. Some may produce flammable hydrogen gas upon contact with metals. Containers may explode when heated. Runoff may create fire or explosion hazard. TOXIC; inhalation or contact with vapor, substance, or decomposition products may cause severe injury
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 B minimum with SCBA required. Full face respiratory protection and chemical-resistant suit. Avoid all contact with moisture.
No. This is a training/quick-reference aid only. Always consult the current ERG Guide 144 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.