☣️ UN 3471 • CLASS 8
Hydrogendifluorides, solution, n.o.s.
Placard: Corrosive. 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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Quick details
UN 3471
Class: 8
Placard type: Corrosive
ERG: Guide 154 (check current ERG)
Isolation: ERG 154: Initial isolation 60m (200 ft) in all directions; Protective Action Distance up to 0.8 km (0.5 mi) downwind for large spills during day
Chemical & Response Details
| Also known as | Bifluoride solutionAcid fluoride solutionHydrogen difluoride solutionHF2- solutionSodium hydrogen difluoride solutionPotassium hydrogen difluoride solution |
| Appearance | Clear to slightly colored aqueous solution with a pungent, irritating odor. Highly corrosive liquid at room temperature. |
| Flash Point | Not applicable (aqueous solution, non-flammable) |
| Boiling Point | Approximately 100-110C (212-230F) depending on concentration |
| Vapor Density | Not applicable (aqueous solution, vapors heavier than air if HF released) |
| Water Reactivity | Already in aqueous solution; dilution with water generates heat and may release hydrogen fluoride vapor |
| Extinguishing | Water spray to reduce vapors, avoid direct water streams that may spread corrosive liquid; CO2 and dry chemical for nearby fires |
| PPE | ⚠️ Level A required for concentrated solutions; full face SCBA, chemical-resistant suit, neoprene or butyl rubber gloves; avoid all skin contact due to severe burns and systemic fluoride toxicity |
| Isolation | ERG 154: Initial isolation 60m (200 ft) in all directions; Protective Action Distance up to 0.8 km (0.5 mi) downwind for large spills during day |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Common hazards (high level)
- 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.
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.
- 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 3471 — Hydrogendifluorides, solution, n.o.s. HAZMAT RADIO NOTE — UN 3471
Product: Hydrogendifluorides, solution, n.o.s.
Class 8 / Corrosive / ERG 154
PPE: Level A required for concentrated solutions; full face SCBA, chemical-resistant suit, neoprene or butyl rubber gloves; avoid all skin contact due to severe burns and systemic fluoride toxicity
ISOLATION: ERG 154: Initial isolation 60m (200 ft) in all directions; Protective Action Distance up to 0.8 km (0.5 mi) downwind for large spills during day
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 3471 — Hydrogendifluorides, solution, n.o.s.
Class: 8 | Placard: Corrosive | ERG Guide: 154
Appearance: Clear to slightly colored aqueous solution with a pungent, irritating odor. Highly corrosive liquid at room temperature.
Water Reactivity: Already in aqueous solution; dilution with water generates heat and may release hydrogen fluoride vapor
Extinguishing: Water spray to reduce vapors, avoid direct water streams that may spread corrosive liquid; CO2 and dry chemical for nearby fires
PPE: Level A required for concentrated solutions; full face SCBA, chemical-resistant suit, neoprene or butyl rubber gloves; avoid all skin contact due to severe burns and systemic fluoride toxicity
Isolation: ERG 154: Initial isolation 60m (200 ft) in all directions; Protective Action Distance up to 0.8 km (0.5 mi) downwind for large spills during day
— 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/3471 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief. Full chemical + response details.
UN3471 Hydrogendifluorides, solution, n.o.s. Cls8 ERG154 | allfirefighter.com/hazmat/un/3471SMS / 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/3471
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FAQ
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 required for concentrated solutions; full face SCBA, chemical-resistant suit, neoprene or butyl rubber gloves; avoid all skin contact due to severe burns and systemic fluoride toxicity
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.