UN 1740 — Hydrogendifluorides, solid, n.o.s.
Placard: Corrosive. ERG Guide 154. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 1740 is Hydrogendifluorides, solid, n.o.s., 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 1740 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 1740 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 1740 should emphasize toxic/corrosive exposure routes, water or oxidizer incompatibility where applicable, air monitoring, PPE selection, decontamination and runoff containment. Use ERG 154, SDS and local SOP.
Regulatory context: Hydrogendifluorides, solid, n.o.s. 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: Hydrogendifluorides, solid, n.o.s. should be stored in tightly closed compatible containers in a cool, dry, well-ventilated area away from water, moisture, bases, oxidizers/reducing agents where incompatible, heat and unauthorized access. Protect containers from corrosion, leakage and contamination.
UN 1740 Quick Details
Common Hazards of UN 1740
- 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 to colorless crystalline solids or powders with no distinct odor or a slight acidic odor. Corrosive in nature and may be hygroscopic.
| Also known as | hydrogen difluorideacid fluoridebifluoride saltsacidic fluoride compoundsHF2- compounds |
| Appearance | White to colorless crystalline solids or powders with no distinct odor or a slight acidic odor. Corrosive in nature and may be hygroscopic. |
| Flash Point | Not applicable (non-flammable solid) |
| Boiling Point | Decomposes before boiling, typically above 200C (392F) depending on specific compound |
| Vapor Density | Not applicable (solid) |
| Water Reactivity | Reacts with water to release hydrofluoric acid (HF) fumes, highly toxic and corrosive |
Fireground Response Guidance — UN 1740
Extinguishing Media
PPE Requirements
Use positive-pressure SCBA for vapor, fume, dust, fire or confined-space exposure. Chemical-resistant gloves, boots, eye/face protection and protective clothing should be selected from SDS; Level A may be needed for close entry or unknown concentrations.
Isolation & Evacuation
First Actions for a UN 1740 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, mist or gas 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, gas, 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 1740 — Hydrogendifluorides, solid, 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.