UN 3471 — Hydrogendifluorides, solution, n.o.s.
Placard: Corrosive. ERG Guide 154. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 3471 is Hydrogendifluorides, solution, n.o.s., a corrosive fluoride solution assigned to ERG Guide 154. Fluoride burns, HF fumes and contaminated runoff are key concerns.
Hazard overview: CORROSIVE fluoride solution, n.o.s.; contact can severely burn skin, eyes and respiratory tissue. Fluoride exposure can cause deep tissue injury and systemic toxicity depending on concentration. Acids or heat may release hydrogen fluoride-containing fumes.
Response guidance: For UN 3471, isolate the spill, avoid fuming dust/mist and use SCBA with acid/fluoride protection. Control water reaction and runoff under ERG 154.
Firefighter training notes: Training for UN 3471 should emphasize exposure routes, SCBA use, vapor/dust monitoring, decontamination, runoff containment and SDS verification. Use ERG 154, SDS and local SOP.
Regulatory context: Hydrogendifluorides, solution, n.o.s. is regulated as a hazardous material for transport and emergency response. Storage, reporting, exposure, waste and incident-notification duties depend on quantity, concentration, formulation and jurisdiction; verify shipping papers, SDS and authority guidance.
Storage & handling: Hydrogendifluorides, solution, n.o.s. should be stored in tightly closed compatible containers with ventilation, secondary containment, restricted access and SDS-based segregation from incompatible materials.
UN 3471 Quick Details
Common Hazards of UN 3471
- CORROSIVE fluoride solution, n.o.s.; contact can severely burn skin, eyes and respiratory tissue.
- Fluoride exposure can cause deep tissue injury and systemic toxicity depending on concentration.
- Acids or heat may release hydrogen fluoride-containing fumes.
- Solution may react with glass, metals or incompatible materials depending on composition.
- Fire may produce toxic/corrosive fluoride fumes.
- Runoff may be acidic/fluoride-contaminated and harmful to waterways.
- Exact hydrogendifluoride salt, concentration and pH must be verified from SDS.
Chemical Identity & Physical Properties
Clear to slightly colored aqueous solution with a pungent, irritating odor. Highly corrosive liquid at room temperature.
| 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 |
Fireground Response Guidance — UN 3471
Extinguishing Media
PPE Requirements
Use positive-pressure SCBA and acid/fluoride-resistant chemical protective clothing. Level A may be needed for fuming, splash or unknown concentration.
Isolation & Evacuation
First Actions for a UN 3471 Incident
- Call 911 and the emergency response number on the shipping paper, if available.
- Keep unauthorized personnel away and establish incident command.
- Stay upwind, uphill and upstream.
- Avoid breathing vapor, dust, mist, smoke or fumes and avoid skin or eye contact.
- Keep water, acids/bases or incompatible materials controlled until product-specific guidance is confirmed.
- Do not touch damaged containers, equipment or spilled material without proper training and PPE.
- Prevent contaminated liquid, dust, runoff and decontamination waste from spreading.
- Ventilate confined spaces only after monitoring and only if properly trained and equipped.
- Use ERG Guide 154, SDS, shipping papers and monitoring to set isolation, evacuation and entry decisions.
📋 Copy & Share Field Card
UN 3471 — Hydrogendifluorides, solution, n.o.s.Use for: Quick radio or face-to-face size-up. Short, structured, field-ready.
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief.
Use for: Quick text to command or incoming units. Fits in a single SMS.