UN 2439 — Sodium hydrogendifluoride
Placard: Corrosive. ERG Guide 154. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 2439 At a Glance
UN 2439 (Sodium hydrogendifluoride) is listed as DOT Class 8 Corrosive and is assigned to ERG Guide 154. Use this page to review placard data, common hazards, PPE notes, isolation context, first actions, and related UN numbers.
UN 2439 is Sodium hydrogendifluoride, a toxic corrosive fluoride salt assigned to ERG Guide 154. Water can form hydrogen-fluoride-containing corrosive solution.
Hazard overview: TOXIC and CORROSIVE fluoride salt; inhalation, ingestion or skin contact may cause severe injury. Dissolves in water to form corrosive and toxic hydrogen fluoride-containing solution. Dust or solution can burn eyes, skin and respiratory tissue.
Response guidance: For UN 2439, isolate the area, avoid skin contact and use SCBA where dust, vapor, mist or fire is present. Contain toxic/corrosive runoff and verify exact product controls with SDS and ERG 154.
Firefighter training notes: Training for UN 2439 should emphasize toxic/corrosive exposure routes, skin absorption, SCBA use, decontamination, runoff containment and SDS verification. Use ERG 154, SDS and local SOP.
Regulatory context: Sodium hydrogendifluoride is regulated as a hazardous material for transport and emergency response. Storage, exposure, spill reporting, waste and fire-code duties depend on quantity, concentration and jurisdiction; verify shipping papers, SDS and local authority requirements.
Storage & handling: Sodium hydrogendifluoride should be stored dry in tightly closed compatible containers away from moisture, bases, metals where incompatible and unauthorized access. Provide containment for acidic/corrosive runoff.
UN 2439 Quick Details
Common Hazards of UN 2439
- TOXIC and CORROSIVE fluoride salt; inhalation, ingestion or skin contact may cause severe injury.
- Dissolves in water to form corrosive and toxic hydrogen fluoride-containing solution.
- Dust or solution can burn eyes, skin and respiratory tissue.
- Non-combustible, but heating can release corrosive fluoride fumes.
- Contact with metals may generate flammable hydrogen gas under some conditions.
- Runoff may be acidic/fluoride-contaminated and harmful to waterways.
- Avoid dust generation and all skin/eye contact.
Chemical Identity & Physical Properties
White crystalline solid or powder. Odorless or slight acidic odor. Stable at room temperature.
| Also known as | Sodium bifluorideSodium hydrogen fluorideSodium acid fluorideNaHF2 |
| CAS Number | 1333-83-1 |
| Appearance | White crystalline solid or powder. Odorless or slight acidic odor. Stable at room temperature. |
| Flash Point | Not applicable (non-combustible solid) |
| Boiling Point | Not applicable (decomposes before boiling) |
| Vapor Density | Not applicable (solid) |
| Water Reactivity | Dissolves in water producing corrosive and toxic hydrogen fluoride solution |
Fireground Response Guidance — UN 2439
Extinguishing Media
PPE Requirements
Use positive-pressure SCBA and chemical-resistant protective clothing. Level A may be needed for heavy vapor, fuming, splash risk or unknown concentrations.
Isolation & Evacuation
First Actions for a UN 2439 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.
- Do not touch damaged containers or spilled material without proper training and PPE.
- Prevent contaminated dust, liquid, 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 2439 — Sodium hydrogendifluorideUse 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.