UN 2709 — Butylbenzenes
Placard: Flammable. ERG Guide 128. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
Butylbenzenes are flammable aromatic hydrocarbon liquids. Isomer composition may vary, so responders should verify product details on the SDS.
Hazard overview: Butylbenzenes presents a flammable vapor hazard. Vapor can move along surfaces, enter drains or low spots and flash back to the spill or container.
Response guidance: Eliminate ignition sources, isolate the release and keep product out of sewers. Use Alcohol-resistant foam, dry chemical, CO2 and water spray for cooling for fire control, and cool exposed containers from a protected position.
Firefighter training notes: Train crews to identify Butylbenzenes by UN number, placard, ERG guide and SDS before choosing entry, isolation or extinguishment tactics.
Regulatory context: Use UN 2709, ERG 128, SDS, container labels and shipping papers to confirm the exact hazard profile and protective action distances.
Storage & handling: Store in closed, compatible containers away from heat, ignition sources and incompatible materials; keep the area ventilated and protected from damage.
UN 2709 Quick Details
Common Hazards of UN 2709
- Highly flammable liquid; vapors may ignite from heat, sparks, static or open flame.
- Vapors can form explosive mixtures with air and travel to a distant ignition source.
- Heavier-than-air vapors may collect in low areas, confined spaces, drains or sewers.
- Runoff to drains can create fire or vapor explosion hazards.
- Containers exposed to fire may rupture or explode from pressure buildup.
- Liquid contact may irritate skin and eyes; inhalation may cause dizziness or respiratory irritation.
- Fire may produce irritating or toxic smoke.
Chemical Identity & Physical Properties
Clear colorless to pale yellow oily liquid with a weak aromatic hydrocarbon odor; immiscible with water.
| Also known as | n-ButylbenzeneMonobutylbenzenePhenylbutane1-Phenylbutane |
| CAS Number | 104-51-8 |
| Appearance | Clear, colorless to pale yellow liquid with a weak aromatic hydrocarbon odor. Oily consistency, immiscible with water. |
| Flash Point | 47°C (117°F) |
| Boiling Point | 183°C (361°F) |
| Vapor Density | 4.6 (heavier than air) |
| Water Reactivity | No significant reaction; floats on water and can spread a surface fire |
Fireground Response Guidance — UN 2709
Extinguishing Media
PPE Requirements
Use SCBA in vapor areas or fire conditions with chemical-resistant gloves, splash protection and protective clothing.
Isolation & Evacuation
First Actions for a UN 2709 Incident
- Call 911 and the emergency response number shown on shipping papers or container documents.
- Keep unauthorized personnel away and establish an initial isolation perimeter.
- Stay upwind, uphill and upstream; avoid low areas where vapors or runoff may collect.
- Avoid breathing vapors, dust, smoke or mist and prevent skin and eye contact.
- Eliminate ignition sources, stop traffic through vapor areas and keep product out of drains and sewers.
- Do not touch damaged containers or spilled material without appropriate chemical PPE.
- Ventilate confined spaces only when personnel are trained, monitored and properly equipped.
- Use ERG guidance, SDS, shipping papers and air monitoring before committing crews.
📋 Copy & Share Field Card
UN 2709 — ButylbenzenesUse 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.