☣️ UN 1343 • CLASS 4

UN 1343 — Phosphorus trisulphide, 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.

UN 1343 is Phosphorus trisulphide, free from yellow and white phosphorus, a water-reactive Class 4 material assigned to ERG Guide 139. It can release toxic hydrogen sulfide and acidic products when exposed to water or moisture.

Hazard overview: UN 1343 presents water-reactive, flammable gas and toxic hydrogen sulfide hazards. Moisture can generate heat and H2S, and the material may ignite or re-ignite if water, foam or contaminated runoff reaches it.

Response guidance: For a UN 1343 incident, responders should verify the product with shipping papers, package markings, SDS and ERG Guide 139. Establish incident command, isolate the area, stay upwind, avoid unnecessary disturbance of powder or damaged packaging, and use only extinguishing agents compatible with the specific material.

Firefighter training notes: Training for UN 1343 should emphasize water-reactive sulfide behavior, hydrogen sulfide monitoring, dry-agent selection and downwind toxic gas control. Common errors include using water or foam directly, entering low areas without H2S monitoring and underestimating re-ignition. Use ERG 139, SDS and hazmat SOP.

Regulatory context: Phosphorus trisulphide, free from yellow and white phosphorus is regulated as a hazardous material for transportation and emergency response purposes. Transportation, workplace exposure, spill reporting, waste handling, storage and environmental requirements may vary by formulation, quantity and jurisdiction. Verify current requirements through shipping papers, SDS, facility documents and applicable DOT, OSHA, EPA, NFPA, state or local authority guidance.

Storage & handling: Phosphorus trisulphide, free from yellow and white phosphorus should be stored in tightly closed compatible containers in a cool, dry, well-ventilated area away from water, moisture, acids, oxidizers, heat and ignition sources. Protect containers from damage and keep dry spill-control materials available where required.

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UN 1343 Quick Details

UN 1343
Product name: Phosphorus trisulphide, free from yellow and white phosphorus
DOT Class: 4
Placard type: Flammable Solid
ERG Guide: 139 (check current ERG)
Initial isolation: ERG 139: Initial isolation 100m in all directions. Protective action distance up to 800m downwind for large spills. Evacuate immediate area if fire develops.

Common Hazards of UN 1343

  • DANGEROUS WHEN WET; contact with water or moisture can release flammable and toxic hydrogen sulfide gas.
  • May ignite on contact with water or moist air.
  • Reaction with water may generate heat, phosphoric acid products and toxic/corrosive fumes.
  • May be ignited by heat, sparks or flames and may re-ignite after apparent extinguishment.
  • Containers may rupture or explode when heated.
  • Runoff or water application may spread contamination and increase toxic gas generation.
  • Hydrogen sulfide can be rapidly dangerous in low or poorly ventilated areas.

Chemical Identity & Physical Properties

Grayish-yellow to greenish-yellow crystalline solid with a characteristic odor similar to rotten eggs or garlic. Free from yellow and white phosphorus impurities.

Also known asPhosphorus sesquisulfideTetraphosphorus trisulfidePhosphorus sulfideP4S3Trisulfurated phosphorus
CAS Number1314-85-8
AppearanceGrayish-yellow to greenish-yellow crystalline solid with a characteristic odor similar to rotten eggs or garlic. Free from yellow and white phosphorus impurities.
Flash PointNot applicable (ignites spontaneously when in contact with moisture or friction)
Boiling Point407-408C (765-766F) with decomposition
Vapor DensityNot applicable (solid material)
Water ReactivityReacts with water producing toxic and flammable hydrogen sulfide (H2S) and phosphoric acid. May ignite spontaneously on contact with moisture.
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.

Fireground Response Guidance — UN 1343

Extinguishing Media

Use dry chemical, dry sand, soda ash or dry earth only if compatible and directed by incident command. Do not apply water, foam or CO2 directly to the material because water contact can produce toxic H2S and heat.

PPE Requirements

⚠️ Level B minimum with full-face SCBA required. Chemical-resistant suit for spill cleanup. Respiratory protection mandatory due to toxic H2S gas evolution.

Use positive-pressure SCBA for any suspected hydrogen sulfide, fire, vapor or confined-space exposure. Chemical-resistant clothing, gloves and eye/face protection should be selected from SDS and incident command; monitoring for H2S is important.

Isolation & Evacuation

ERG 139: Initial isolation 100m in all directions. Protective action distance up to 800m downwind for large spills. Evacuate immediate area if fire develops.
Always confirm protective actions with the current edition of the Emergency Response Guidebook (ERG Guide 139).

First Actions for a UN 1343 Incident

  • CALL 911. Then call the emergency response telephone number on the shipping paper, if available.
  • Keep unauthorized personnel away.
  • Stay upwind, uphill and/or upstream.
  • Avoid low areas where hydrogen sulfide or other heavy gases may collect.
  • Do not touch spilled material or damaged containers unless properly trained and equipped.
  • Keep water, foam and moisture away from the released material unless incident command confirms a compatible cooling or control use.
  • Ventilate closed spaces before entering, but only if properly trained, equipped and authorized by incident command.
  • Isolate the spill or leak area and expand the perimeter if water contact, fire or H2S detection is suspected.
  • Use ERG Guide 139, shipping papers, SDS, air monitoring and incident command for protective actions.
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📋 Copy & Share Field Card

UN 1343 — Phosphorus trisulphide, free from yellow
HAZMAT RADIO NOTE — UN 1343 Product: Phosphorus trisulphide, free from yellow and white phosphorus Class 4 / Flammable Solid / ERG 139 PPE: Level B minimum with full-face SCBA required. Chemical-resistant suit for spill cleanup. Respiratory protection mandatory due to toxic H2S gas evolution. ISOLATION: ERG 139: Initial isolation 100m in all directions. Protective action distance up to 800m downwind for large spills. Evacuate immediate area if fire develops. ACTION: Stage upwind · Isolate · Deny entry · Request HazmatRADIO

Use for: Quick radio or face-to-face size-up. Short, structured, field-ready.

SMS WhatsApp
=== IC HAZMAT BRIEFING === UN 1343 — Phosphorus trisulphide, free from yellow and white phosphorus Class: 4 | Placard: Flammable Solid | ERG Guide: 139 Appearance: Grayish-yellow to greenish-yellow crystalline solid with a characteristic odor similar to rotten eggs or garlic. Free from yellow and white phosphorus impurities. Water Reactivity: Reacts with water producing toxic and flammable hydrogen sulfide (H2S) and phosphoric acid. May ignite spontaneously on contact with moisture. Extinguishing: Use dry chemical, dry sand, soda ash or dry earth only if compatible and directed by incident command. Do not apply water, foam or CO2 directly to the material because water contact can produce toxic H2S and heat. PPE: Level B minimum with full-face SCBA required. Chemical-resistant suit for spill cleanup. Respiratory protection mandatory due to toxic H2S gas evolution. Isolation: ERG 139: Initial isolation 100m in all directions. Protective action distance up to 800m downwind for large spills. Evacuate immediate area if fire develops. — Key Hazards — • DANGEROUS WHEN WET; contact with water or moisture can release flammable and toxic hydrogen sulfide gas. • May ignite on contact with water or moist air. • Reaction with water may generate heat, phosphoric acid products and toxic/corrosive fumes. — First Actions — • CALL 911. Then call the emergency response telephone number on the shipping paper, if available. • Keep unauthorized personnel away. • Stay upwind, uphill and/or upstream. • Avoid low areas where hydrogen sulfide or other heavy gases may collect. SOURCE: allfirefighter.com/hazmat/un/phosphorus-trisulphide-free-from-un-1343 | Always use current ERG + SOP/SOGIC BRIEFING

Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief.

SMS (short)
UN1343 Phosphorus trisulphide, free from yellow and white phosphorus Cls4 ERG139 | allfirefighter.com/hazmat/un/phosphorus-trisulphide-free-from-un-1343SMS / 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-trisulphide-free-from-un-1343

Related UN Numbers in Class 4

Discovery block for training / quick reference. Always consult the current ERG + your SOP/SOG for operations.
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Frequently Asked Questions about UN 1343

UN 1343 is Phosphorus trisulphide, free from yellow and white phosphorus, a hazardous material assigned to ERG Guide 139.

Yes. It may ignite on contact with water or moist air and can produce flammable hydrogen sulfide gas.

ERG Guide 139 applies to UN 1343 for initial isolation, protective actions and first response guidance.

UN 1343 presents water-reactive, flammable gas and toxic hydrogen sulfide hazards. Moisture can generate heat and H2S, and the material may ignite or re-ignite if water, foam or contaminated runoff reaches it.

Use positive-pressure SCBA for any suspected hydrogen sulfide, fire, vapor or confined-space exposure. Chemical-resistant clothing, gloves and eye/face protection should be selected from SDS and incident command; monitoring for H2S is important.

Do not apply water or foam directly to the material unless incident command and product guidance confirm a safe use, because water contact can generate toxic hydrogen sulfide and heat.
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.