☣️ UN 1340 • CLASS 4
UN 1340 — Phosphorus pentasulphide, free from yellow and white phosphorus
Placard: Dangerous When Wet. ERG Guide 139. 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 1340 Quick Details
UN 1340
Product name: Phosphorus pentasulphide, free from yellow and white phosphorus
DOT Class: 4
Placard type: Dangerous When Wet
ERG Guide: 139 (check current ERG)
Initial isolation: ERG 139: Initially isolate 100m in all directions. Protect personnel from toxic hydrogen sulfide gas. If fire or large spill, isolate 800m and evacuate downwind areas.
Common Hazards of UN 1340
- 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.
Chemical Identity & Physical Properties
| Also known as | Phosphorus pentasulfidePhosphoric sulfideDiphosphorus pentasulfideThiophosphoric anhydrideP2S5 |
| CAS Number | 1314-80-3 |
| Appearance | Greenish-yellow to light yellow crystalline solid with a characteristic odor resembling hydrogen sulfide. Hygroscopic material that is sensitive to moisture. |
| Flash Point | Not applicable (reacts with moisture before ignition temperature reached) |
| Boiling Point | 514C (957F) - decomposes at 513C |
| Vapor Density | Not applicable (solid) |
| Water Reactivity | Reacts violently with water producing toxic hydrogen sulfide gas and phosphoric acid. Produces heat that may ignite combustible materials. Keep dry at all times. |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Fireground Response Guidance — UN 1340
Extinguishing Media
Dry chemical, sand, or dry earth only. Do NOT use water, foam, or CO2. Use approved Class D extinguishers for metal fires if available.
PPE Requirements
⚠️ Level B minimum with SCBA required. Full chemical protective suit for large spills. Protect against hydrogen sulfide exposure which is highly toxic.
Isolation & Evacuation
ERG 139: Initially isolate 100m in all directions. Protect personnel from toxic hydrogen sulfide gas. If fire or large spill, isolate 800m and evacuate downwind areas.
Always confirm protective actions with the current edition of the Emergency Response Guidebook (ERG Guide 139).
First Actions for a UN 1340 Incident
- 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 1340 — Phosphorus pentasulphide, free from yellHAZMAT RADIO NOTE — UN 1340
Product: Phosphorus pentasulphide, free from yellow and white phosphorus
Class 4 / Dangerous When Wet / ERG 139
PPE: Level B minimum with SCBA required. Full chemical protective suit for large spills. Protect against hydrogen sulfide exposure which is highly toxic.
ISOLATION: ERG 139: Initially isolate 100m in all directions. Protect personnel from toxic hydrogen sulfide gas. If fire or large spill, isolate 800m and evacuate downwind areas.
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 1340 — Phosphorus pentasulphide, free from yellow and white phosphorus
Class: 4 | Placard: Dangerous When Wet | ERG Guide: 139
Appearance: Greenish-yellow to light yellow crystalline solid with a characteristic odor resembling hydrogen sulfide. Hygroscopic material that is sensitive to moisture.
Water Reactivity: Reacts violently with water producing toxic hydrogen sulfide gas and phosphoric acid. Produces heat that may ignite combustible materials. Keep dry at all times.
Extinguishing: Dry chemical, sand, or dry earth only. Do NOT use water, foam, or CO2. Use approved Class D extinguishers for metal fires if available.
PPE: Level B minimum with SCBA required. Full chemical protective suit for large spills. Protect against hydrogen sulfide exposure which is highly toxic.
Isolation: ERG 139: Initially isolate 100m in all directions. Protect personnel from toxic hydrogen sulfide gas. If fire or large spill, isolate 800m and evacuate downwind areas.
— 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/1340 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief. Full chemical + response details.
UN1340 Phosphorus pentasulphide, free from yellow and white phosphorus Cls4 ERG139 | allfirefighter.com/hazmat/un/1340SMS / 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/1340
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Frequently Asked Questions about UN 1340
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 B minimum with SCBA required. Full chemical protective suit for large spills. Protect against hydrogen sulfide exposure which is highly toxic.
Water reactivity: Reacts violently with water producing toxic hydrogen sulfide gas and phosphoric acid. Produces heat that may ignite combustible materials. Keep dry at all times.. Recommended extinguishing: Dry chemical, sand, or dry earth only. Do NOT use water, foam, or CO2. Use approved Class D extinguishers for metal fires if available..
ERG Guide 139 recommendation: ERG 139: Initially isolate 100m in all directions. Protect personnel from toxic hydrogen sulfide gas. If fire or large spill, isolate 800m and evacuate downwind areas.
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.