UN 3149 — Hydrogen peroxide and peroxyacetic acid mixture, with acid(s), water and not more than 5% peroxyacetic acid, stabilized
Placard: Oxidizer. ERG Guide 140. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 3149 is a stabilized mixture of hydrogen peroxide and peroxyacetic acid with water and acid. It is an oxidizer and corrosive irritant rather than a normal flammable liquid.
Hazard overview: The mixture can feed a fire by releasing oxygen and can decompose if heated or contaminated. Vapors and splashes may injure skin, eyes and airways.
Response guidance: Isolate the release, keep combustibles and contaminants away, and cool exposed containers with water spray from a protected position if compatible with the incident. Prevent runoff from entering drains when safe.
Firefighter training notes: Train crews to avoid contaminating peroxide mixtures with dirty tools, organic absorbents or metals. Watch for bulging containers, venting and heat as decomposition indicators.
Regulatory context: UN 3149 is a Class 5.1 oxidizer entry. Concentrations and stabilizers must match shipping papers and SDS for safe storage and response.
Storage & handling: Store cool, ventilated and away from fuels, reducing agents, metals, dirt, organic materials and heat. Keep containers vented or compatible as specified by the supplier.
UN 3149 Quick Details
Common Hazards of UN 3149
- Oxidizing liquid mixture that can intensify fire and react with organic material.
- Contains hydrogen peroxide and peroxyacetic acid; vapors may be irritating or corrosive.
- Decomposition can release oxygen, heat and pressure in containers.
- Contamination with metals, dirt, reducing agents or incompatible organics may accelerate decomposition.
- Contact can cause skin, eye and respiratory burns or irritation.
- Runoff may be corrosive and harmful to waterways.
- Closed containers may rupture if heated or contaminated.
Chemical Identity & Physical Properties
Clear to pale yellow liquid with a pungent, vinegar-like odor. Corrosive aqueous solution containing oxidizing agents Concentration and stabilizer package affect odor, decomposition risk and response decisions.
| Also known as | Hydrogen peroxide-peroxyacetic acid mixturePeracetic acid-hydrogen peroxide solutionPAA-H2O2 mixtureStabilized peroxide-peracid blend |
| Appearance | Clear to pale yellow liquid with a pungent, vinegar-like odor. Corrosive aqueous solution containing oxidizing agents. |
| Flash Point | Not applicable (non-flammable oxidizer) |
| Boiling Point | Approximately 100-110C (212-230F), varies with concentration |
| Vapor Density | Greater than 1 (heavier than air) |
| Water Reactivity | Miscible with water; dilution reduces reactivity but generates heat |
Fireground Response Guidance — UN 3149
Extinguishing Media
PPE Requirements
Use SCBA for vapors or fire involvement and wear chemical splash protection with compatible gloves and suit. Avoid contaminated clothing because oxidizers may worsen ignition risk.
Isolation & Evacuation
First Actions for a UN 3149 Incident
- Call 911 and the emergency response number shown on the shipping paper, if available.
- Keep unauthorized personnel away and establish incident command before close approach.
- Stay upwind, uphill and upstream; avoid low areas where vapors or gases may collect.
- Avoid breathing vapors, dust, mist or fire gases and avoid skin or eye contact.
- Do not touch damaged containers or spilled material without proper PPE and training.
- Ventilate confined spaces only if trained, equipped and authorized by incident command.
- Use ERG guidance, SDS, shipping papers and monitoring results for final protective actions.
📋 Copy & Share Field Card
UN 3149 — Hydrogen peroxide and peroxyacetic acidUse 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.