UN 3111 — Organic peroxide type B, liquid, temperature controlled
Placard: Organic Peroxide. ERG Guide 148. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 3111 is Organic peroxide type B, liquid, temperature controlled, a temperature-controlled organic peroxide assigned to ERG Guide 148. Loss of cooling can lead to runaway decomposition.
Hazard overview: Temperature-controlled type B organic peroxide liquid; loss of temperature control can lead to self-accelerating decomposition. May burn rapidly with a flare effect and may ignite nearby combustibles. Refrigeration failure, warm storage or delayed cooling can quickly increase pressure and explosion risk.
Response guidance: For UN 3111, isolate widely, keep heat/shock/friction/contamination away and cool exposed containers from protection if safe. Follow SDS temperature limits and ERG 148.
Firefighter training notes: Training for UN 3111 should emphasize organic peroxide instability, SADT/control temperature, contamination avoidance, remote cooling, evacuation triggers and runoff control. Use ERG 148, SDS and local SOP.
Regulatory context: Organic peroxide type B, liquid, temperature controlled is regulated as a hazardous material for transport and emergency response. Storage, reporting, exposure, waste and incident-notification duties depend on quantity, formulation, temperature-control status and jurisdiction; verify shipping papers, SDS and authority guidance.
Storage & handling: Organic peroxide type B, liquid, temperature controlled should be stored in approved peroxide-compatible containers away from heat, sunlight, friction, contamination, acids, bases, metals, reducing agents and combustibles. Maintain required temperature control and emergency cooling plans.
UN 3111 Quick Details
Common Hazards of UN 3111
- Temperature-controlled type B organic peroxide liquid; loss of temperature control can lead to self-accelerating decomposition.
- May burn rapidly with a flare effect and may ignite nearby combustibles.
- Refrigeration failure, warm storage or delayed cooling can quickly increase pressure and explosion risk.
- Containers may rupture or explode when heated or if decomposition starts.
- Contamination with acids, bases, metals, reducing agents or organic material can increase instability.
- Fire may produce irritating, corrosive and toxic gases.
- Runoff may carry reactive peroxide contamination.
- Exact formulation, dilution, control temperature and emergency temperature must be verified from SDS and shipping papers.
Chemical Identity & Physical Properties
Varies by specific peroxide formulation; typically clear to pale yellow liquids with characteristic peroxide odor. These are highly reactive organic compounds containing the peroxy (-O-O-) functional group that are stored and transported under controlled temperature conditions.
| Also known as | Organic peroxide type B liquidTemperature-controlled organic peroxideSelf-reactive liquid type BThermally unstable organic peroxide |
| Appearance | Varies by specific peroxide formulation; typically clear to pale yellow liquids with characteristic peroxide odor. These are highly reactive organic compounds containing the peroxy (-O-O-) functional group that are stored and transported under controlled temperature conditions. |
| Flash Point | Not applicable (self-reactive material, does not require ignition source) |
| Boiling Point | Varies by formulation; decomposes exothermically before reaching normal boiling point |
| Vapor Density | Typically >1 (heavier than air), but varies by specific peroxide compound |
| Water Reactivity | Generally stable in water but avoid contamination; water may be used for cooling containers in fire situations |
Fireground Response Guidance — UN 3111
Extinguishing Media
PPE Requirements
Use positive-pressure SCBA, chemical-resistant protective clothing and distance/blast protection. Avoid contaminated PPE, friction, heat and direct contact.
Isolation & Evacuation
First Actions for a UN 3111 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.
- Eliminate ignition sources and keep heat, friction, shock and contamination away from the material.
- Check temperature-control status and request specialist support if cooling is lost or containers are warming.
- Avoid breathing vapor, dust, mist, smoke or fumes and avoid skin or eye contact.
- Do not touch damaged containers or spilled material without proper training and PPE.
- Prevent contaminated liquid, dust, runoff and decontamination waste from spreading.
- Ventilate confined spaces only after monitoring and only if properly trained and equipped.
- Use ERG Guide 148, SDS, shipping papers and monitoring to set isolation, evacuation and entry decisions.
📋 Copy & Share Field Card
UN 3111 — Organic peroxide type B, liquid, temperaUse 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.