UN 2556 — Nitrocellulose with alcohol, not less than 25% alcohol
Placard: Flammable Solid. ERG Guide 113. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 2556 is nitrocellulose wetted with not less than 25% alcohol. It combines flammable solid behavior with flammable alcohol vapor and a major dried-material sensitivity concern.
Hazard overview: The alcohol wetting agent helps desensitize the nitrocellulose, but it also adds vapor ignition risk. If the material dries, it can become highly sensitive to heat, flame, friction or shock.
Response guidance: Control ignition sources, isolate the area and prevent drying. Use compatible agents such as alcohol-resistant foam, dry chemical or CO2 for fire conditions, and use water spray mainly for cooling when appropriate.
Firefighter training notes: Train crews to recognize alcohol vapor hazards plus dried nitrocellulose sensitivity. Include static control, standoff and solvent-compatible foam selection.
Regulatory context: UN 2556 is transported as Nitrocellulose with alcohol, not less than 25% alcohol, Class 4 flammable solid. Confirm wetting percentage and solvent type.
Storage & handling: Keep containers closed and wetted with the specified alcohol content. Store away from heat, sparks, oxidizers and conditions that allow drying.
UN 2556 Quick Details
Common Hazards of UN 2556
- Nitrocellulose wetted with at least 25% alcohol is a flammable solid with flammable solvent vapor concerns.
- If the material dries out, sensitivity to heat, flame, friction or shock increases sharply.
- Alcohol vapors may ignite and can spread to low or confined areas.
- Fire can produce irritating and toxic smoke.
- Containers may rupture when heated.
- Runoff to drains may carry flammable alcohol and contaminated nitrocellulose.
- Static discharge, sparks and rough handling can increase ignition risk.
Chemical Identity & Physical Properties
The material is typically a white to slightly yellow fibrous or cotton-like mass with a slight alcohol odor when properly wetted.
| Also known as | Cellulose nitrateGuncottonCollodion cottonPyroxylinNitrated cellulose |
| CAS Number | 9004-70-0 |
| Appearance | White to slightly yellow fibrous solid or cotton-like material, odorless or slight alcoholic odor when wetted. Supplied as a slurry or wet mass with alcohol to maintain stability. |
| Flash Point | 12C (55F) for alcohol wetted material |
| Boiling Point | Not applicable (decomposes before boiling) |
| Vapor Density | Not applicable (solid material, vapors from alcohol carrier) |
| Water Reactivity | No significant reaction with water, but drying increases explosion hazard |
Fireground Response Guidance — UN 2556
Extinguishing Media
PPE Requirements
Use SCBA for vapor, smoke or fire. Wear protective clothing, gloves and eye protection; maintain standoff if the material is dry or fire-involved.
Isolation & Evacuation
First Actions for a UN 2556 Incident
- Call 911 and the emergency response number on the shipping papers.
- Keep unauthorized personnel away and control ignition sources.
- Stay upwind, uphill and upstream of vapor, smoke and runoff.
- Avoid breathing vapor or smoke; avoid contact with wet or dried material.
- Do not handle dried material or damaged containers without PPE and explosive-hazard precautions.
- Ventilate confined spaces only if trained, equipped and monitoring confirms safe entry.
- Use ERG 113, SDS and shipping papers to verify solvent content and dried-material precautions.
📋 Copy & Share Field Card
UN 2556 — Nitrocellulose with alcohol, not less thUse 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.