☣️ UN 1381 • CLASS 4
UN 1381 — Phosphorus, yellow, dry or under water or in solution
Placard: Spontaneously Combustible. ERG Guide 136. 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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UN 1381 Quick Details
UN 1381
Product name: Phosphorus, yellow, dry or under water or in solution
DOT Class: 4
Placard type: Spontaneously Combustible
ERG Guide: 136 (check current ERG)
Initial isolation: ERG 136: Isolate spill 50m all directions; if tank/rail car involved in fire, isolate 800m and consider evacuation 1600m in all directions
Common Hazards of UN 1381
- Extremely flammable; will ignite itself if exposed to air.
- Burns rapidly, releasing dense, white, irritating fumes.
- Substance may be transported in a molten form.
- May re-ignite after fire is extinguished.
- Corrosives in contact with metals may evolve flammable hydrogen gas.
- Containers may explode when heated.
- Fire will produce irritating, corrosive and/or toxic gases.
- TOXIC and/or CORROSIVE; ingestion of substance or inhalation of decomposition products will cause
Chemical Identity & Physical Properties
| Also known as | White phosphorusYellow phosphorusTetraphosphorusP4WP |
| CAS Number | 12185-10-3 |
| Appearance | Waxy, translucent solid ranging from white to yellow in color. Garlic-like odor. Stored under water or inert atmosphere to prevent spontaneous ignition. May be shipped molten. |
| Flash Point | Not applicable (pyrophoric - ignites spontaneously in air at approximately 30C/86F) |
| Boiling Point | 280C (536F) |
| Vapor Density | 4.4 (heavier than air) |
| Water Reactivity | No significant reaction with water; typically stored under water to prevent air exposure and spontaneous ignition |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Fireground Response Guidance — UN 1381
Extinguishing Media
Dry sand, soda ash, or special dry chemical. DO NOT use water, foam, or CO2 on burning phosphorus. Water may be used to keep containers cool.
PPE Requirements
⚠️ Level A required for large spills or fire conditions; SCBA mandatory; full chemical-resistant suit; prevent any skin contact as burns are severe and deep
Isolation & Evacuation
ERG 136: Isolate spill 50m all directions; if tank/rail car involved in fire, isolate 800m and consider evacuation 1600m in all directions
Always confirm protective actions with the current edition of the Emergency Response Guidebook (ERG Guide 136).
First Actions for a UN 1381 Incident
- CALL 911. Then call emergency response telephone number on shipping paper. If shipping paper
- Stay upwind, uphill and/or upstream.
- Keep unauthorized personnel away.
- 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 1381 — Phosphorus, yellow, dry or under water oHAZMAT RADIO NOTE — UN 1381
Product: Phosphorus, yellow, dry or under water or in solution
Class 4 / Spontaneously Combustible / ERG 136
PPE: Level A required for large spills or fire conditions; SCBA mandatory; full chemical-resistant suit; prevent any skin contact as burns are severe and deep
ISOLATION: ERG 136: Isolate spill 50m all directions; if tank/rail car involved in fire, isolate 800m and consider evacuation 1600m in all directions
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 1381 — Phosphorus, yellow, dry or under water or in solution
Class: 4 | Placard: Spontaneously Combustible | ERG Guide: 136
Appearance: Waxy, translucent solid ranging from white to yellow in color. Garlic-like odor. Stored under water or inert atmosphere to prevent spontaneous ignition. May be shipped molten.
Water Reactivity: No significant reaction with water; typically stored under water to prevent air exposure and spontaneous ignition
Extinguishing: Dry sand, soda ash, or special dry chemical. DO NOT use water, foam, or CO2 on burning phosphorus. Water may be used to keep containers cool.
PPE: Level A required for large spills or fire conditions; SCBA mandatory; full chemical-resistant suit; prevent any skin contact as burns are severe and deep
Isolation: ERG 136: Isolate spill 50m all directions; if tank/rail car involved in fire, isolate 800m and consider evacuation 1600m in all directions
— Key Hazards —
• Extremely flammable; will ignite itself if exposed to air.
• Burns rapidly, releasing dense, white, irritating fumes.
• Substance may be transported in a molten form.
— First Actions —
• CALL 911. Then call emergency response telephone number on shipping paper. If shipping paper
• Stay upwind, uphill and/or upstream.
• Keep unauthorized personnel away.
• Isolate spill or leak area in all directions for at least 50 meters (150 feet) for liquids and at least 25 meters
SOURCE: allfirefighter.com/hazmat/un/1381 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief. Full chemical + response details.
UN1381 Phosphorus, yellow, dry or under water or in solution Cls4 ERG136 | allfirefighter.com/hazmat/un/1381SMS / 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/1381
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Frequently Asked Questions about UN 1381
Extremely flammable; will ignite itself if exposed to air. Burns rapidly, releasing dense, white, irritating fumes. Substance may be transported in a molten form. May re-ignite after fire is extinguished. Corrosives in contact with metals may evolve flammable hydrogen gas. Containers may explode when heated. Fire will produce irritating, corrosive and/or toxic gases. TOXIC and/or CORROSIVE; ingestion of substance or inhalation of decomposition products will cause
CALL 911. Then call emergency response telephone number on shipping paper. If shipping paper Stay upwind, uphill and/or upstream. Keep unauthorized personnel away.
Level A required for large spills or fire conditions; SCBA mandatory; full chemical-resistant suit; prevent any skin contact as burns are severe and deep
Water reactivity: No significant reaction with water; typically stored under water to prevent air exposure and spontaneous ignition. Recommended extinguishing: Dry sand, soda ash, or special dry chemical. DO NOT use water, foam, or CO2 on burning phosphorus. Water may be used to keep containers cool..
ERG Guide 136 recommendation: ERG 136: Isolate spill 50m all directions; if tank/rail car involved in fire, isolate 800m and consider evacuation 1600m in all directions
No. This is a training/quick-reference aid only. Always consult the current ERG Guide 136 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.