☣️ UN 1339 • CLASS 4
UN 1339 — Phosphorus heptasulphide, free from yellow and white phosphorus
Placard: Flammable Solid. 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.
Phosphorus heptasulphide, free from yellow and white phosphorus is a highly reactive, flammable solid that can ignite spontaneously when in contact with water or moist air. It is essential to handle this substance with extreme caution.
Hazard overview: Phosphorus heptasulphide, free from yellow and white phosphorus can produce flammable and toxic gases on contact with water. It may also ignite on contact with water or moist air.
Response guidance: In case of fire, use dry chemical, dry sand, or dry earth only; do NOT use water, foam, or CO2.
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UN 1339 Quick Details
UN 1339
Product name: Phosphorus heptasulphide, free from yellow and white phosphorus
DOT Class: 4
Placard type: Flammable Solid
ERG Guide: 139 (check current ERG)
Initial isolation: ERG 139: isolate spill or leak area at least 25m in all directions; if fire or water contact, isolate 800m and consider evacuation 1600m downwind
Common Hazards of UN 1339
- 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
The substance appears as a light yellow to greenish-yellow crystalline solid with a characteristic sulfide odor.
| Also known as | Phosphorus heptasulfideTetraphosphorus heptasulfideP4S7Phosphorus sulfide (P4S7) |
| CAS Number | 12037-82-0 |
| Appearance | Light yellow to greenish-yellow crystalline solid with a characteristic sulfide odor. Stable at room temperature when dry. |
| Flash Point | Not applicable (ignites spontaneously when exposed to moisture or humid air) |
| Boiling Point | Not applicable (decomposes at approximately 310C/590F) |
| Vapor Density | Not applicable (solid material) |
| Water Reactivity | Reacts vigorously with water producing toxic and flammable hydrogen sulfide (H2S) and phosphoric acid; may ignite spontaneously |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Fireground Response Guidance — UN 1339
Extinguishing Media
Dry chemical, dry sand, or dry earth only; do NOT use water, foam, or CO2
PPE Requirements
⚠️ Level B minimum with SCBA required; full chemical protective clothing recommended due to toxic gas production and potential ignition
Level B minimum with SCBA required; full chemical protective clothing recommended due to toxic gas production and potential ignition.
Isolation & Evacuation
ERG 139: isolate spill or leak area at least 25m in all directions; if fire or water contact, isolate 800m and consider evacuation 1600m downwind
Always confirm protective actions with the current edition of the Emergency Response Guidebook (ERG Guide 139).
First Actions for a UN 1339 Incident
- 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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📋 Copy & Share Field Card
UN 1339 — Phosphorus heptasulphide, free from yellHAZMAT RADIO NOTE — UN 1339
Product: Phosphorus heptasulphide, free from yellow and white phosphorus
Class 4 / Flammable Solid / ERG 139
PPE: Level B minimum with SCBA required; full chemical protective clothing recommended due to toxic gas production and potential ignition
ISOLATION: ERG 139: isolate spill or leak area at least 25m in 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 1339 — Phosphorus heptasulphide, free from yellow and white phosphorus
Class: 4 | Placard: Flammable Solid | ERG Guide: 139
Appearance: Light yellow to greenish-yellow crystalline solid with a characteristic sulfide odor. Stable at room temperature when dry.
Water Reactivity: Reacts vigorously with water producing toxic and flammable hydrogen sulfide (H2S) and phosphoric acid; may ignite spontaneously
Extinguishing: Dry chemical, dry sand, or dry earth only; do NOT use water, foam, or CO2
PPE: Level B minimum with SCBA required; full chemical protective clothing recommended due to toxic gas production and potential ignition
Isolation: ERG 139: isolate spill or leak area at least 25m in all directions; if fire or water contact, isolate 800m and consider evacuation 1600m downwind
— 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 —
• 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
SOURCE: allfirefighter.com/hazmat/un/phosphorus-heptasulphide-free-from-un-1339 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief.
UN1339 Phosphorus heptasulphide, free from yellow and white phosphorus Cls4 ERG139 | allfirefighter.com/hazmat/un/phosphorus-heptasulphide-free-from-un-1339SMS / 160 CHAR
Use for: Quick text to command or incoming units. Fits in a single SMS.
⚠️ Quick-reference only. Always use current ERG + SOP/SOG for incident-specific actions.
Page: https://allfirefighter.com/hazmat/un/phosphorus-heptasulphide-free-from-un-1339
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Frequently Asked Questions about UN 1339
Yes, UN 1339 is a flammable solid.
Yes, UN 1339 can ignite spontaneously when in contact with water or moist air.
Level B minimum with SCBA required; full chemical protective clothing recommended.
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.