UN 2426 — Ammonium nitrate, liquid (hot concentrated solution)
Placard: Oxidizer. ERG Guide 140. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 2426 is Ammonium nitrate, liquid (hot concentrated solution), a hot concentrated oxidizer solution assigned to ERG Guide 140. Heat, contamination and confinement are the main escalation risks.
Hazard overview: OXIDIZER hot concentrated solution; can accelerate burning of nearby combustible materials. May decompose violently if strongly heated, confined, contaminated or involved in a large fire. Contamination with fuels, oils, organic materials, reducing agents or metals can greatly increase hazard.
Response guidance: For UN 2426, isolate the area, remove combustibles and prevent contamination with fuel, oil or organics. Cool containers from protection, use water-based cooling/flooding tactics when safe and follow ERG 140.
Firefighter training notes: Training for UN 2426 should emphasize oxidizer contamination control, heat/decomposition signs, incompatible fuels/organics, container cooling, evacuation and runoff control. Use ERG 140, SDS and local SOP.
Regulatory context: Ammonium nitrate, liquid (hot concentrated solution) 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: Ammonium nitrate, liquid (hot concentrated solution) should be stored in compatible oxidizer-rated containers with temperature control where required, away from fuels, oils, organics, reducing agents, acids where incompatible and combustible contamination.
UN 2426 Quick Details
Common Hazards of UN 2426
- OXIDIZER hot concentrated solution; can accelerate burning of nearby combustible materials.
- May decompose violently if strongly heated, confined, contaminated or involved in a large fire.
- Contamination with fuels, oils, organic materials, reducing agents or metals can greatly increase hazard.
- Hot solution can cause thermal burns and nitrate-contaminated runoff.
- Decomposition may release nitrogen oxides and ammonia-containing fumes.
- Containers may rupture or explode when heated.
- Runoff may carry oxidizer contamination and intensify fire where combustibles are present.
Chemical Identity & Physical Properties
Clear to slightly yellow liquid with no odor or faint ammonia odor. Hot concentrated aqueous solution (typically 80-95% concentration) maintained above crystallization point.
| Also known as | Ammonium nitrate solutionNitric acid ammonium salt solutionAN solutionHot concentrated ammonium nitrate liquor |
| CAS Number | 6484-52-2 |
| Appearance | Clear to slightly yellow liquid with no odor or faint ammonia odor. Hot concentrated aqueous solution (typically 80-95% concentration) maintained above crystallization point. |
| Flash Point | Not applicable (non-flammable oxidizer) |
| Boiling Point | Approximately 100-120C (212-248F) depending on concentration |
| Vapor Density | Not applicable (low volatility liquid) |
| Water Reactivity | Miscible with water; dilution releases heat |
Fireground Response Guidance — UN 2426
Extinguishing Media
PPE Requirements
Use positive-pressure SCBA for fire, decomposition fumes or confined spaces. Wear chemical-resistant clothing, eye/face protection and thermal protection for hot solution.
Isolation & Evacuation
First Actions for a UN 2426 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 fuels, oils, organics, reducing agents and combustible contamination away from the oxidizer.
- Do not touch damaged containers or spilled material without proper training and PPE.
- Ventilate confined spaces only after monitoring and only if properly trained and equipped.
- Use ERG Guide 140, SDS, shipping papers and monitoring to set isolation, evacuation and entry decisions.
📋 Copy & Share Field Card
UN 2426 — Ammonium nitrate, liquid (hot concentratUse 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.