UN 3515 — Adsorbed gas, poisonous, oxidizing, n.o.s. (Inhalation Hazard Zone A)
Placard: Toxic Gas. ERG Guide 173. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 3515 is Adsorbed gas, poisonous, oxidizing, n.o.s. (Inhalation Hazard Zone A), a Zone A toxic oxidizing adsorbed gas entry assigned to ERG Guide 173. Exact gas identity controls isolation and compatibility.
Hazard overview: Adsorbed gas package containing toxic oxidizing gas; release may create an immediate inhalation hazard. Inhalation Hazard Zone A entries may be fatal at very low airborne concentrations. Gas is held on a porous solid adsorbent, but damage, heating or valve failure can release free gas.
Response guidance: For UN 3515, isolate downwind/low areas, treat as a life-threatening gas release and use Level A/SCBA for entry. Verify exact gas with shipping papers and ERG 173.
Firefighter training notes: Training for UN 3515 should emphasize toxic-gas recognition, Zone A isolation, Level A/SCBA entry, air monitoring, source-control limits and decontamination. Use ERG 173, SDS and local SOP.
Regulatory context: Adsorbed gas, poisonous, oxidizing, n.o.s. (Inhalation Hazard Zone A) is regulated as a hazardous material for transport and emergency response. Storage, reporting, exposure, waste and incident-notification duties depend on quantity, package type, gas identity and jurisdiction; verify shipping papers, SDS and authority guidance.
Storage & handling: Adsorbed gas, poisonous, oxidizing, n.o.s. (Inhalation Hazard Zone A) should be stored in secured compatible adsorbed-gas packages away from heat, impact, corrosion, moisture where incompatible and unauthorized access, with ventilation and emergency planning.
UN 3515 Quick Details
Common Hazards of UN 3515
- Adsorbed gas package containing toxic oxidizing gas; release may create an immediate inhalation hazard.
- Inhalation Hazard Zone A entries may be fatal at very low airborne concentrations.
- Gas is held on a porous solid adsorbent, but damage, heating or valve failure can release free gas.
- Released gas behavior, odor warning and vapor density depend on the exact gas identity.
- Oxidizing gas may ignite or greatly intensify combustibles, oils, greases or reducing agents.
- Water or moisture may form toxic/corrosive products depending on the gas.
- Runoff or vapor-control water may become toxic and oxidizing.
- Containers exposed to fire may vent, rupture or release toxic gas.
Chemical Identity & Physical Properties
This is a generic entry for various toxic oxidizing gases adsorbed onto solid porous materials such as activated carbon or molecular sieves. The physical appearance depends on the specific gas and adsorbent used, typically appearing as cylinders or containers filled with granular solid material containing the adsorbed gas.
| Also known as | Adsorbed toxic gas, oxidizing, n.o.s.Poisonous oxidizing gas adsorbedToxic oxidizing gas on solid adsorbentHazard Zone A oxidizing toxic gas |
| Appearance | This is a generic entry for various toxic oxidizing gases adsorbed onto solid porous materials such as activated carbon or molecular sieves. The physical appearance depends on the specific gas and adsorbent used, typically appearing as cylinders or containers filled with granular solid material containing the adsorbed gas. |
| Flash Point | Not applicable (oxidizing gas) |
| Boiling Point | Not applicable (adsorbed gas on solid substrate) |
| Vapor Density | Varies by specific gas; typically heavier than air when released |
| Water Reactivity | May react with water depending on specific gas; oxidizing properties may intensify reactions |
Fireground Response Guidance — UN 3515
Extinguishing Media
PPE Requirements
Use Level A fully encapsulating chemical protective clothing with positive-pressure SCBA for entry. Zone A toxic gas requires maximum respiratory and skin protection.
Isolation & Evacuation
First Actions for a UN 3515 Incident
- Call 911 and the emergency response number on the shipping paper, if available.
- Keep unauthorized personnel away and establish incident command.
- Stay upwind and avoid low or poorly ventilated areas unless monitoring shows they are safe.
- Treat the release as a life-threatening inhalation hazard until the gas is identified and monitored.
- Keep fuels, oils, greases, combustibles and reducing agents away from oxidizing gas.
- Do not handle leaking cylinders, adsorbed-gas packages or damaged gas articles without proper training and PPE.
- Ventilate only after monitoring and only if properly trained and equipped.
- Use ERG Guide 173, shipping papers, markings and air monitoring to set isolation, evacuation and entry decisions.
📋 Copy & Share Field Card
UN 3515 — Adsorbed gas, poisonous, oxidizing, n.o.Use 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.