UN 2351 — Butyl nitrites
Placard: Flammable. ERG Guide 129. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 2351 is Butyl nitrites, a flammable organic nitrite entry assigned to ERG Guide 129. Vapor fire risk and nitrogen oxide decomposition products are key concerns.
Hazard overview: FLAMMABLE organic nitrite liquid; vapors may ignite and form explosive mixtures with air. Vapors are heavier than air and may travel to ignition sources and flash back. Exposure may cause headache, dizziness, blood pressure effects or methemoglobinemia-type concerns depending on dose.
Response guidance: For UN 2351, isolate the spill, eliminate ignition sources and keep vapors out of drains. Use SCBA, cool heated containers from a protected distance and monitor for nitrogen oxide fumes.
Firefighter training notes: Training for UN 2351 should emphasize toxic vapor recognition, SCBA use, skin-contact prevention, sewer flashback, container cooling, decontamination and runoff control. Use ERG 129, SDS and local SOP.
Regulatory context: Butyl nitrites 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: Butyl nitrites should be stored in approved flammable-liquid containers away from heat, ignition sources, oxidizers, acids and contamination. Keep containers closed and follow SDS temperature limits.
UN 2351 Quick Details
Common Hazards of UN 2351
- FLAMMABLE organic nitrite liquid; vapors may ignite and form explosive mixtures with air.
- Vapors are heavier than air and may travel to ignition sources and flash back.
- Exposure may cause headache, dizziness, blood pressure effects or methemoglobinemia-type concerns depending on dose.
- Heating or fire may release nitrogen oxides and irritating/toxic gases.
- Runoff to sewers may create fire, explosion and contamination hazards.
- Material may decompose if heated, contaminated or stored improperly.
- Containers may rupture or explode when heated.
Chemical Identity & Physical Properties
Clear to pale yellow liquid with a fruity, sweet odor. Highly volatile at room temperature.
| Also known as | Butyl nitriten-Butyl nitriteNitrous acid butyl ester1-Butyl nitriteIsobutyl nitrite |
| CAS Number | 544-16-1 |
| Appearance | Clear to pale yellow liquid with a fruity, sweet odor. Highly volatile at room temperature. |
| Flash Point | -9C (16F) |
| Boiling Point | 78C (172F) |
| Vapor Density | 3.6 (heavier than air) |
| Water Reactivity | No significant reaction; slightly soluble in water |
Fireground Response Guidance — UN 2351
Extinguishing Media
PPE Requirements
Use positive-pressure SCBA for vapor, fire or confined-space exposure. Wear chemical-resistant gloves, boots, eye/face protection and protective clothing; avoid skin contact.
Isolation & Evacuation
First Actions for a UN 2351 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; keep responders out of low vapor areas.
- Eliminate ignition sources if this can be done safely.
- Avoid breathing vapor, mist or smoke and avoid skin or eye contact.
- Watch for decomposition or nitrogen oxide fumes if containers are heated.
- 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 129, SDS, shipping papers and air monitoring to set isolation, evacuation and entry decisions.
📋 Copy & Share Field Card
UN 2351 — Butyl nitritesUse 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.