UN 1727 — Ammonium hydrogendifluoride, solid
Placard: Corrosive. ERG Guide 154. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 1727 is Ammonium hydrogendifluoride, solid, a toxic corrosive fluoride solid assigned to ERG Guide 154. Moisture can form acidic fluoride solution and may release hydrogen fluoride-type fumes.
Hazard overview: UN 1727 presents fluoride dust, corrosive skin/eye injury and contaminated-runoff hazards. Heating, moisture or fire may release toxic/corrosive fluoride gases.
Response guidance: For a UN 1727 incident, responders should verify the product with shipping papers, package markings, SDS and ERG Guide 154. Establish incident command, isolate the area, stay upwind, prevent incompatible contact, control runoff and choose entry or fire-control actions based on monitoring, SDS and local SOP.
Firefighter training notes: Training for UN 1727 should emphasize corrosive/toxic exposure routes, air monitoring, PPE selection, decontamination, runoff containment and compatible extinguishing decisions. Use ERG 154, SDS and local SOP.
Regulatory context: Ammonium hydrogendifluoride, solid is regulated as a hazardous material for transportation and emergency response purposes. Transportation, workplace exposure, spill reporting, waste handling, storage and environmental requirements may vary by concentration, formulation, quantity and jurisdiction. Verify current requirements through shipping papers, SDS, facility documents and applicable DOT, OSHA, EPA, NFPA, state or local authority guidance.
Storage & handling: Ammonium hydrogendifluoride, solid should be stored in tightly closed compatible containers in a secure, cool, dry, well-ventilated hazardous-material area according to SDS and local procedures.
UN 1727 Quick Details
Common Hazards of UN 1727
- TOXIC and CORROSIVE fluoride solid; inhalation, ingestion or skin contact may cause severe injury.
- Moisture or water can form acidic fluoride solution and may release hydrogen fluoride-type fumes.
- Dust can seriously irritate or injure eyes, skin and respiratory tissue.
- Heating or fire may release corrosive/toxic fluoride gases.
- Runoff may carry toxic fluoride contamination.
- Containers may rupture or fail when heated.
- Avoid all skin contact and prevent dust from becoming airborne.
Chemical Identity & Physical Properties
White crystalline solid or powder with a sharp, pungent odor. Deliquescent (absorbs moisture from air).
| Also known as | Ammonium bifluorideAmmonium hydrogen fluorideAmmonium acid fluorideABF |
| CAS Number | 1341-49-7 |
| Appearance | White crystalline solid or powder with a sharp, pungent odor. Deliquescent (absorbs moisture from air). |
| Flash Point | Not applicable (non-flammable solid) |
| Boiling Point | Decomposes at 240C (464F) releasing hydrogen fluoride gas |
| Vapor Density | Not applicable (solid) |
| Water Reactivity | Soluble in water, forming acidic and corrosive solution. Hydrolyzes to release hydrogen fluoride in moist conditions. |
Fireground Response Guidance — UN 1727
Extinguishing Media
PPE Requirements
Use positive-pressure SCBA for dust, fume, fire or confined-space exposure. Wear chemical-resistant clothing, gloves and eye/face protection suitable for fluoride/corrosive exposure; avoid skin contact and contaminated dust.
Isolation & Evacuation
First Actions for a UN 1727 Incident
- CALL 911. Then call the emergency response telephone number on the shipping paper, if available.
- Keep unauthorized personnel away.
- Stay upwind, uphill and/or upstream.
- Avoid breathing vapors, fumes, dust or mist and avoid skin or eye contact.
- Do not touch or walk through spilled material unless properly trained and wearing appropriate protective equipment.
- Ventilate closed spaces before entering, but only if properly trained, equipped, monitored and authorized by incident command.
- Isolate the spill or leak area and expand the perimeter if vapor, dust, fire involvement, water reaction or unknown concentration is present.
- Use ERG Guide 154, shipping papers, SDS, air monitoring and incident command for protective actions.
📋 Copy & Share Field Card
UN 1727 — Ammonium hydrogendifluoride, solidUse 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.