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 At a Glance
UN 2426 (Ammonium nitrate, liquid (hot concentrated solution)) is listed as DOT Class 5 Oxidizer and is assigned to ERG Guide 140. Use this page to review placard data, common hazards, PPE notes, isolation context, first actions, and related UN numbers.
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.