☣️ UN 3118 • CLASS 5
UN 3118 — Organic peroxide type E, solid, temperature controlled
Placard: Organic Peroxide. ERG Guide 148. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
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⚠️ Verification required:
Temperature-controlled organic peroxide category; verify exact formulation, control temperature, emergency temperature, SDS and shipping papers.
⚠️ This page is a quick-reference aid. For real incidents: stage upwind, isolate, deny entry, request Hazmat early, and consult the current ERG + SOP/SOG.
Organic peroxide type E, solid, temperature controlled is a temperature-controlled Class 5.2 organic peroxide. The exact formulation matters, but the key field concern is preventing heat buildup, contamination and loss of control temperature.
Hazard overview: UN 3118 can decompose violently if it warms beyond its control limits or becomes contaminated. Fire exposure may rupture containers, intensify burning and release irritating or toxic decomposition products.
Response guidance: Keep responders upwind and protect the temperature-controlled cargo from heat. Cool threatened containers from maximum distance, avoid contamination, and use shipping papers or SDS to confirm control temperature and compatible agents.
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UN 3118 Quick Details
UN 3118
Product name: Organic peroxide type E, solid, temperature controlled
DOT Class: 5
Placard type: Organic Peroxide
ERG Guide: 148 (check current ERG)
Initial isolation: Use ERG 148, shipping papers and temperature data. Increase isolation immediately if refrigeration is lost, cargo is heating, or containers are fire-exposed.
Common Hazards of UN 3118
- Temperature-controlled organic peroxide Type E; heat, contamination or loss of refrigeration can cause rapid decomposition.
- Decomposition may generate heat, pressure, flammable vapors and irritating or toxic smoke.
- May ignite combustibles and can burn intensely once involved in fire.
- Containers may rupture or explode when heated or when internal pressure rises.
- Contamination with acids, bases, metals, reducing agents, dirt or incompatible absorbents can start decomposition.
- Avoid friction, impact, sparks and open flame; some formulations are shock or heat sensitive.
- Runoff or spilled product can spread fire risk and contaminate soil or waterways.
Chemical Identity & Physical Properties
The material is shipped as a temperature-controlled solid; color, odor and concentration vary by peroxide formulation. Treat appearance details as product-specific and verify the SDS.
| Also known as | Organic peroxide type E solidTemperature-controlled organic peroxide solidSelf-reactive substance type EThermally unstable peroxide solid |
| Appearance | Typically white to off-white crystalline or granular solid at room temperature. May be odorless or have a characteristic sharp, acrid odor. Requires temperature control during transport to prevent decomposition. |
| Flash Point | Not applicable (self-reactive solid) |
| Boiling Point | Not applicable (decomposes before boiling) |
| Vapor Density | Not applicable (solid) |
| Water Reactivity | Exact formulation controls compatibility. Water may be used from a distance for cooling, but direct contamination can accelerate decomposition; verify SDS. |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Fireground Response Guidance — UN 3118
Extinguishing Media
Use water spray/fog from maximum distance to cool unopened containers. For small incipient fires, dry chemical or CO2 may be used if safe; avoid contaminating product.
PPE Requirements
⚠️ SCBA and chemical-resistant protective clothing required; use Level A or B based on release size and monitoring. Maintain distance because of explosion risk.
Wear SCBA with chemical-resistant protection. Use Level A for unknown or significant releases, Level B where monitoring and incident command support it, and keep crews outside blast-risk areas.
Isolation & Evacuation
Use ERG 148, shipping papers and temperature data. Increase isolation immediately if refrigeration is lost, cargo is heating, or containers are fire-exposed.
Always confirm protective actions with the current edition of the Emergency Response Guidebook (ERG Guide 148).
First Actions for a UN 3118 Incident
- Call 911 and the emergency response number shown on shipping papers.
- Keep unauthorized personnel away and establish an isolation zone.
- Stay upwind, uphill and upstream; avoid low areas where vapors or gases may collect.
- Avoid breathing vapors, dust, smoke or decomposition gases and avoid skin or eye contact.
- Do not touch damaged packages, containers or spilled material without proper PPE.
- Ventilate confined spaces only if responders are trained, equipped and monitoring the atmosphere.
- Confirm control and emergency temperatures from shipping papers or SDS before moving or cooling cargo.
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📋 Copy & Share Field Card
UN 3118 — Organic peroxide type E, solid, temperatHAZMAT RADIO NOTE — UN 3118
Product: Organic peroxide type E, solid, temperature controlled
Class 5 / Organic Peroxide / ERG 148
PPE: SCBA and chemical-resistant protective clothing required; use Level A or B based on release size and monitoring. Maintain distance because of explosion risk.
ISOLATION: Use ERG 148, shipping papers and temperature data. Increase isolation immediately if refrigeration is lost, cargo is heating, or containers are fire-exposed.
ACTION: Stage upwind · Isolate · Deny entry · Request HazmatRADIO
Use for: Quick radio or face-to-face size-up. Short, structured, field-ready.
=== IC HAZMAT BRIEFING ===
UN 3118 — Organic peroxide type E, solid, temperature controlled
Class: 5 | Placard: Organic Peroxide | ERG Guide: 148
Appearance: Typically white to off-white crystalline or granular solid at room temperature. May be odorless or have a characteristic sharp, acrid odor. Requires temperature control during transport to prevent decomposition.
Water Reactivity: Exact formulation controls compatibility. Water may be used from a distance for cooling, but direct contamination can accelerate decomposition; verify SDS.
Extinguishing: Use water spray/fog from maximum distance to cool unopened containers. For small incipient fires, dry chemical or CO2 may be used if safe; avoid contaminating product.
PPE: SCBA and chemical-resistant protective clothing required; use Level A or B based on release size and monitoring. Maintain distance because of explosion risk.
Isolation: Use ERG 148, shipping papers and temperature data. Increase isolation immediately if refrigeration is lost, cargo is heating, or containers are fire-exposed.
— Key Hazards —
• Temperature-controlled organic peroxide Type E; heat, contamination or loss of refrigeration can cause rapid decomposition.
• Decomposition may generate heat, pressure, flammable vapors and irritating or toxic smoke.
• May ignite combustibles and can burn intensely once involved in fire.
— First Actions —
• Call 911 and the emergency response number shown on shipping papers.
• Keep unauthorized personnel away and establish an isolation zone.
• Stay upwind, uphill and upstream; avoid low areas where vapors or gases may collect.
• Avoid breathing vapors, dust, smoke or decomposition gases and avoid skin or eye contact.
SOURCE: allfirefighter.com/hazmat/un/organic-peroxide-type-e-un-3118 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief.
UN3118 Organic peroxide type E, solid, temperature controlled Cls5 ERG148 | allfirefighter.com/hazmat/un/organic-peroxide-type-e-un-3118SMS / 160 CHAR
Use for: Quick text to command or incoming units. Fits in a single SMS.
⚠️ Quick-reference only. Always use current ERG + SOP/SOG for incident-specific actions.
Page: https://allfirefighter.com/hazmat/un/organic-peroxide-type-e-un-3118
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Frequently Asked Questions about UN 3118
UN 3118 is a temperature-controlled Type E organic peroxide solid. The exact product and control temperature must be verified from shipping papers and the SDS.
Heat or loss of refrigeration can start self-accelerating decomposition, creating pressure, fire and explosion hazards.
It is a Class 5.2 organic peroxide. It can intensify fire and ignite combustible materials even though behavior varies by formulation.
Water spray or fog may be used from a safe distance for cooling containers, but direct contamination of product should be avoided unless SDS confirms compatibility.
SCBA and chemical-resistant clothing are required; Level A or B is selected by release size, monitoring results and incident command.
Check shipping papers and SDS for the control temperature, emergency temperature, formulation, stabilizer and compatible extinguishing/cooling methods.
Sources (high level): DOT/PHMSA marking & class concepts + ERG usage principles.
This page does not reproduce ERG guide text—always consult the current ERG for incident-specific protective actions.