UN 3056 — n-Heptaldehyde
Placard: Flammable. ERG Guide 129. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
n-Heptaldehyde (UN 3056) is a flammable aldehyde liquid. First responders should control ignition sources, manage heavier-than-air vapors and avoid liquid or vapor exposure.
Hazard overview: UN 3056 presents a flammable vapor hazard with flashback potential. Aldehyde vapors can irritate responders, and fire may produce irritating smoke and carbon oxides.
Response guidance: Isolate the spill, remove ignition sources and keep personnel out of low areas. Use alcohol-resistant foam, dry chemical or CO2 for fire control; cool containers with water spray from a safe distance and keep runoff out of sewers.
Firefighter training notes: Train crews to recognize aldehyde vapor irritation, flashback potential and sewer explosion hazards during UN 3056 releases.
Regulatory context: UN 3056 is regulated as a flammable liquid; ERG 129 and SDS data should guide isolation, foam and PPE decisions.
Storage & handling: Store in flammable-liquid storage away from oxidizers, acids, bases, heat and ignition sources with bonding and grounding as required.
UN 3056 Quick Details
Common Hazards of UN 3056
- Flammable liquid; vapors can ignite from heat, sparks or flames.
- Vapors are heavier than air and may travel along the ground to flash back.
- Vapor exposure may irritate eyes, skin and respiratory tract.
- Liquid can spread on surfaces and may float or form a slick on water.
- Fire may produce irritating aldehyde vapors and carbon oxides.
- Runoff to sewers may create fire or explosion hazards.
- Containers may rupture when heated.
Chemical Identity & Physical Properties
Colorless to pale yellow liquid with a pungent, fatty, fruity odor. Oily consistency at room temperature.
| Also known as | heptanalheptaldehydeenanthaldehydeenanthalenanthic aldehydeoenanthaldehydeoenanthic aldehyde |
| CAS Number | 111-71-7 |
| Appearance | Colorless to pale yellow liquid with a pungent, fatty, fruity odor. Oily consistency at room temperature. |
| Flash Point | 46C (115F) |
| Boiling Point | 153C (307F) |
| Vapor Density | 4.0 (heavier than air) |
| Water Reactivity | No significant reaction with water; slightly soluble |
Fireground Response Guidance — UN 3056
Extinguishing Media
PPE Requirements
Use positive-pressure SCBA for vapor or fire conditions and chemical-resistant gloves and splash protection for liquid contact.
Isolation & Evacuation
First Actions for a UN 3056 Incident
- Call 911 and the emergency response number on the shipping paper, if available.
- Eliminate ignition sources; use non-sparking tools and control traffic around the spill.
- Keep unauthorized personnel away and stay upwind, uphill and upstream.
- Avoid breathing vapors and prevent liquid contact with skin, eyes and clothing.
- Do not enter low areas, drains or confined spaces unless trained and equipped.
- Use ERG 131, SDS, shipping papers and monitoring to set isolation and evacuation distances.
- Contain runoff only if it can be done safely with proper PPE.
📋 Copy & Share Field Card
UN 3056 — n-HeptaldehydeUse 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.