UN 2555 — Nitrocellulose with water, not less than 25% water
Placard: Flammable Solid. ERG Guide 113. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 2555 covers nitrocellulose kept wetted with not less than 25% water. The water reduces sensitivity, but drying can create a serious fire or explosion hazard.
Hazard overview: The critical condition is moisture content. Wetted material is less sensitive, while dried nitrocellulose can ignite or react violently from heat, flame, friction or shock.
Response guidance: Isolate the area and keep the material wet if safe to do so. If material has dried, been heated or is involved in fire, treat the incident with explosive-hazard precautions and follow ERG 113/SDS guidance.
Firefighter training notes: Train crews to check whether nitrocellulose is wetted or dried. Emphasize friction/shock avoidance, wetting strategy and explosive precautions for dry material.
Regulatory context: UN 2555 is shipped as Nitrocellulose with water, not less than 25% water, Class 4 flammable solid. Confirm moisture content on the shipping papers.
Storage & handling: Keep containers closed and wet as specified. Store away from heat, flame, friction, oxidizers and materials that could dry or contaminate the product.
UN 2555 Quick Details
Common Hazards of UN 2555
- Nitrocellulose wetted with at least 25% water is desensitized but remains a flammable solid hazard.
- If the material dries out, it can become much more sensitive to heat, flame, friction or shock.
- Fire can spread rapidly and produce irritating or toxic smoke.
- Runoff to drains can carry burning or contaminated material.
- Containers may rupture when heated.
- Dry residues may behave more like an explosive nitrocellulose hazard.
- Contact with burning or decomposing material can cause burns and irritation.
Chemical Identity & Physical Properties
The material is usually a white to slightly yellow fibrous or cotton-like solid supplied wet with water to maintain stability.
| Also known as | Cellulose nitrateGuncottonPyroxylinNitrocottonFlash paper |
| CAS Number | 9004-70-0 |
| Appearance | White to slightly yellow fibrous solid or cotton-like material. Odorless when pure. Stored wetted with water to prevent ignition. |
| Flash Point | Not applicable (desensitized with water; dry material extremely flammable) |
| Boiling Point | Not applicable (decomposes) |
| Vapor Density | Not applicable (solid) |
| Water Reactivity | No reaction; water acts as desensitizer and must remain above 25% by mass |
Fireground Response Guidance — UN 2555
Extinguishing Media
PPE Requirements
Use SCBA for fire or smoke. Wear protective clothing, gloves and eye protection; dried material requires additional standoff and specialist precautions.
Isolation & Evacuation
First Actions for a UN 2555 Incident
- Call 911 and the emergency response number on the shipping papers.
- Keep unauthorized personnel away and establish an isolation area.
- Stay upwind, uphill and upstream of smoke, spill material and runoff.
- Keep the material wet if it can be done safely and under command direction.
- Avoid breathing smoke or dust; avoid skin and eye contact.
- Do not handle dried or damaged containers without PPE and explosive-hazard awareness.
- Use ERG 113, SDS and shipping papers to confirm whether dried material requires explosive precautions.
📋 Copy & Share Field Card
UN 2555 — Nitrocellulose with water, not less thanUse 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.