☣️ UN 2949 • CLASS 8
UN 2949 — Sodium hydrosulphide, hydrated, with not less than 25% water of crystallization
Placard: Corrosive. ERG Guide 154. 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 2949 Quick Details
UN 2949
Product name: Sodium hydrosulphide, hydrated, with not less than 25% water of crystallization
DOT Class: 8
Placard type: Corrosive
ERG Guide: 154 (check current ERG)
Initial isolation: ERG 154: Initial isolation 50m all directions. Protective action distance: day 0.3km, night 0.9km for large spills. Toxic gas producer.
Common Hazards of UN 2949
- TOXIC and/or CORROSIVE; inhalation, ingestion or skin contact with material may cause severe injury
- Contact with molten substance may cause severe burns to skin and eyes.
- Avoid any skin contact.
- Fire may produce irritating, corrosive and/or toxic gases.
- Runoff from fire control or dilution water may be corrosive and/or toxic and cause environmental
- Non-combustible, substance itself does not burn but may decompose upon heating to produce corrosive
- Some are oxidizers and may ignite combustibles (wood, paper, oil, clothing, etc.).
- Corrosives in contact with metals may evolve flammable hydrogen gas.
Chemical Identity & Physical Properties
| Also known as | Sodium hydrogen sulfide hydrateSodium bisulfide hydrateSodium sulfhydrate hydrateNaHS hydrate |
| CAS Number | 16721-80-5 |
| Appearance | Yellow to orange crystalline solid or flakes with a strong rotten egg (hydrogen sulfide) odor. Deliquescent, absorbs moisture from air. |
| Flash Point | Not applicable (non-flammable solid) |
| Boiling Point | Not applicable (decomposes before boiling) |
| Vapor Density | Not applicable (solid, but releases H2S gas which is heavier than air) |
| Water Reactivity | Dissolves readily releasing heat and toxic hydrogen sulfide gas (H2S). Keep wet to minimize H2S evolution but contact with water is hazardous. |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Fireground Response Guidance — UN 2949
Extinguishing Media
Dry chemical, soda ash, lime. Avoid water streams due to H2S generation. Small fires may use water spray to cool containers.
PPE Requirements
⚠️ Level A or B with SCBA required due to H2S gas hazard. Chemical-resistant suit, gloves, and eye protection. Monitor for H2S vapor.
Isolation & Evacuation
ERG 154: Initial isolation 50m all directions. Protective action distance: day 0.3km, night 0.9km for large spills. Toxic gas producer.
Always confirm protective actions with the current edition of the Emergency Response Guidebook (ERG Guide 154).
First Actions for a UN 2949 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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📋 Copy & Share Field Card
UN 2949 — Sodium hydrosulphide, hydrated, with notHAZMAT RADIO NOTE — UN 2949
Product: Sodium hydrosulphide, hydrated, with not less than 25% water of crystallization
Class 8 / Corrosive / ERG 154
PPE: Level A or B with SCBA required due to H2S gas hazard. Chemical-resistant suit, gloves, and eye protection. Monitor for H2S vapor.
ISOLATION: ERG 154: Initial isolation 50m all directions. Protective action distance: day 0.3km, night 0.9km for large spills. Toxic gas producer.
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 2949 — Sodium hydrosulphide, hydrated, with not less than 25% water of crystallization
Class: 8 | Placard: Corrosive | ERG Guide: 154
Appearance: Yellow to orange crystalline solid or flakes with a strong rotten egg (hydrogen sulfide) odor. Deliquescent, absorbs moisture from air.
Water Reactivity: Dissolves readily releasing heat and toxic hydrogen sulfide gas (H2S). Keep wet to minimize H2S evolution but contact with water is hazardous.
Extinguishing: Dry chemical, soda ash, lime. Avoid water streams due to H2S generation. Small fires may use water spray to cool containers.
PPE: Level A or B with SCBA required due to H2S gas hazard. Chemical-resistant suit, gloves, and eye protection. Monitor for H2S vapor.
Isolation: ERG 154: Initial isolation 50m all directions. Protective action distance: day 0.3km, night 0.9km for large spills. Toxic gas producer.
— Key Hazards —
• TOXIC and/or CORROSIVE; inhalation, ingestion or skin contact with material may cause severe injury
• Contact with molten substance may cause severe burns to skin and eyes.
• Avoid any skin contact.
— 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/2949 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief. Full chemical + response details.
UN2949 Sodium hydrosulphide, hydrated, with not less than 25% water of crystallization Cls8 ERG154 | allfirefighter.com/hazmat/un/2949SMS / 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/2949
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Frequently Asked Questions about UN 2949
TOXIC and/or CORROSIVE; inhalation, ingestion or skin contact with material may cause severe injury Contact with molten substance may cause severe burns to skin and eyes. Avoid any skin contact. Fire may produce irritating, corrosive and/or toxic gases. Runoff from fire control or dilution water may be corrosive and/or toxic and cause environmental Non-combustible, substance itself does not burn but may decompose upon heating to produce corrosive Some are oxidizers and may ignite combustibles (wood, paper, oil, clothing, etc.). Corrosives in contact with metals may evolve flammable hydrogen gas.
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 A or B with SCBA required due to H2S gas hazard. Chemical-resistant suit, gloves, and eye protection. Monitor for H2S vapor.
Water reactivity: Dissolves readily releasing heat and toxic hydrogen sulfide gas (H2S). Keep wet to minimize H2S evolution but contact with water is hazardous.. Recommended extinguishing: Dry chemical, soda ash, lime. Avoid water streams due to H2S generation. Small fires may use water spray to cool containers..
ERG Guide 154 recommendation: ERG 154: Initial isolation 50m all directions. Protective action distance: day 0.3km, night 0.9km for large spills. Toxic gas producer.
No. This is a training/quick-reference aid only. Always consult the current ERG Guide 154 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.