UN 2034 — Hydrogen and methane mixture, compressed
Placard: Flammable Gas. ERG Guide 115. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 2034 is Hydrogen and methane mixture, compressed, a flammable gas entry assigned to ERG Guide 115. The main hazards are ignition, flashback, cylinder rupture and vapor accumulation.
Hazard overview: EXTREMELY FLAMMABLE compressed or liquefied gas; may ignite easily by heat, sparks or flame. Can form explosive mixtures with air and flash back from distant ignition sources. Gas may collect in low or confined areas depending on gas density and ventilation.
Response guidance: For a UN 2034 incident, verify the product with shipping papers, container markings, SDS and ERG Guide 115. Establish incident command, isolate the area, stay upwind, control ignition or incompatibility hazards, prevent runoff or vapor spread and base entry/fire-control actions on monitoring and local SOP.
Firefighter training notes: Training for UN 2034 should emphasize gas vapor travel, flashback, source isolation, cylinder cooling, BLEVE/rocket hazards and ignition control. Use ERG 115, SDS and local SOP.
Regulatory context: Hydrogen and methane mixture, compressed is regulated as a hazardous material for transportation and emergency response purposes. Storage, workplace exposure, emergency planning, spill reporting, waste handling and environmental requirements vary by exact product, concentration, quantity and jurisdiction. Verify current requirements through shipping papers, SDS, container markings and applicable DOT, OSHA, EPA, NFPA, state or local authority guidance.
Storage & handling: Hydrogen and methane mixture, compressed containers should be secured in a cool, ventilated gas storage area away from heat, flames where applicable, physical damage and incompatible materials. Follow SDS and local code for pressure, ventilation and segregation.
UN 2034 Quick Details
Common Hazards of UN 2034
- EXTREMELY FLAMMABLE compressed or liquefied gas; may ignite easily by heat, sparks or flame.
- Can form explosive mixtures with air and flash back from distant ignition sources.
- Gas may collect in low or confined areas depending on gas density and ventilation.
- Cylinders or receptacles exposed to fire may vent, rupture or rocket.
- Contact with rapidly expanding or liquefied gas may cause frostbite or cold burns.
- Fire may produce irritating or toxic decomposition gases depending on product.
- Do not extinguish a leaking gas fire unless the gas flow can be stopped safely.
Chemical Identity & Physical Properties
Colorless, odorless compressed gas mixture stored in high-pressure cylinders. Lighter than air and will rise and disperse rapidly when released.
| Also known as | Hydrogen-methane mixtureCompressed hydrogen-methane gasH2-CH4 mixtureMethane-hydrogen blend |
| Appearance | Colorless, odorless compressed gas mixture stored in high-pressure cylinders. Lighter than air and will rise and disperse rapidly when released. |
| Flash Point | Not applicable (compressed gas mixture) |
| Boiling Point | Not applicable (gas mixture: hydrogen -253C, methane -161C) |
| Vapor Density | 0.3-0.6 (lighter than air, depending on mixture ratio) |
| Water Reactivity | No reaction with water; gas will bubble through and disperse |
Fireground Response Guidance — UN 2034
Extinguishing Media
PPE Requirements
Use positive-pressure SCBA for leak, vapor, fire or confined-space exposure. Wear flame-resistant protection and insulated gloves/eye protection where liquefied or rapidly expanding gas contact is possible.
Isolation & Evacuation
First Actions for a UN 2034 Incident
- CALL 911. Then call the emergency response telephone number on the shipping paper, if available.
- Keep unauthorized personnel away.
- Stay upwind, uphill and/or upstream.
- Avoid breathing vapors, gas, dust, mist, smoke or fumes and avoid skin or eye contact.
- Eliminate ignition sources if safe and keep vapors and runoff out of drains, sewers, basements and low areas.
- Do not touch damaged containers or spilled/released material unless properly trained and wearing appropriate protective equipment.
- Ventilate closed spaces before entering, but only if properly trained, equipped, monitored and authorized by incident command.
- Isolate the spill or release area and expand the perimeter for fire involvement, vapor spread, dust spread, cylinder heating or unknown product identity.
- Use ERG Guide 115, shipping papers, SDS, air monitoring and incident command for protective actions.
📋 Copy & Share Field Card
UN 2034 — Hydrogen and methane mixture, compressedUse 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.