☣️ UN 1931 • CLASS 9
Zinc hydrosulphite
Placard: Miscellaneous. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
🚒☣️
⚠️ 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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Quick details
UN 1931
Class: 9
Placard type: Miscellaneous
ERG: Guide 171 (check current ERG)
Isolation: ERG 171: isolate spill 25m all directions; if fire or large spill isolate 800m all directions, consider evacuation 800m downwind
Chemical & Response Details
| Also known as | Zinc dithioniteZinc hyposulfiteZinc sulfoxylateDithionous acid zinc salt |
| CAS Number | 7779-86-4 |
| Appearance | White to grayish-white crystalline powder or granular solid. Slight sulfurous odor. Solid at room temperature. |
| Flash Point | Not applicable (non-flammable solid) |
| Boiling Point | Not applicable (decomposes before boiling) |
| Vapor Density | Not applicable (solid) |
| Water Reactivity | Decomposes slowly in water releasing sulfur dioxide and heat; reaction accelerates with warm water |
| Extinguishing | Dry chemical, sand, or dry earth; avoid water in large quantities |
| PPE | ⚠️ Level C minimum; respiratory protection for sulfur dioxide exposure; chemical-resistant gloves and clothing |
| Isolation | ERG 171: isolate spill 25m all directions; if fire or large spill isolate 800m all directions, consider evacuation 800m downwind |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Common hazards (high level)
- Some may burn but none ignite readily.
- Containers may explode when heated.
- Some may be transported hot.
- For UN3508, Capacitor, asymmetric, be aware of possible short circuiting as this product is transported
- Polymeric beads, expandable (UN2211) may evolve flammable vapours.
- Inhalation of material may be harmful.
- Contact may cause burns to skin and eyes.
- Inhalation of Asbestos dust may have a damaging effect on the lungs.
First actions (field-minded)
- CALL 911. Then call emergency response telephone number on shipping paper. If shipping paper
- Keep unauthorized personnel away.
- Stay upwind, uphill and/or upstream.
- 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 1931 — Zinc hydrosulphite HAZMAT RADIO NOTE — UN 1931
Product: Zinc hydrosulphite
Class 9 / Miscellaneous / ERG 171
PPE: Level C minimum; respiratory protection for sulfur dioxide exposure; chemical-resistant gloves and clothing
ISOLATION: ERG 171: isolate spill 25m all directions; if fire or large spill isolate 800m all directions, consider evacuation 800m 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 1931 — Zinc hydrosulphite
Class: 9 | Placard: Miscellaneous | ERG Guide: 171
Appearance: White to grayish-white crystalline powder or granular solid. Slight sulfurous odor. Solid at room temperature.
Water Reactivity: Decomposes slowly in water releasing sulfur dioxide and heat; reaction accelerates with warm water
Extinguishing: Dry chemical, sand, or dry earth; avoid water in large quantities
PPE: Level C minimum; respiratory protection for sulfur dioxide exposure; chemical-resistant gloves and clothing
Isolation: ERG 171: isolate spill 25m all directions; if fire or large spill isolate 800m all directions, consider evacuation 800m downwind
— Key Hazards —
• Some may burn but none ignite readily.
• Containers may explode when heated.
• Some may be transported hot.
— 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.
• 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/1931 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief. Full chemical + response details.
UN1931 Zinc hydrosulphite Cls9 ERG171 | ERG 171: isolate spill 25m all directions; if fire or large spill isolate 800m a | allfirefighter.com/hazmat/un/1931SMS / 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/1931
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FAQ
Some may burn but none ignite readily. Containers may explode when heated. Some may be transported hot. For UN3508, Capacitor, asymmetric, be aware of possible short circuiting as this product is transported Polymeric beads, expandable (UN2211) may evolve flammable vapours. Inhalation of material may be harmful. Contact may cause burns to skin and eyes. Inhalation of Asbestos dust may have a damaging effect on the lungs.
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 C minimum; respiratory protection for sulfur dioxide exposure; chemical-resistant gloves and clothing
No. This is a training/quick-reference aid only. Always consult the current ERG Guide 171 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.