UN 3539 — Articles containing toxic gas, n.o.s.
Placard: Toxic Gas. ERG Guide 123. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 3539 is Articles containing toxic gas, n.o.s., a broad toxic gas article entry assigned to ERG Guide 123. Gas identity and package damage control response.
Hazard overview: Articles containing toxic gas, n.o.s.; damaged articles can release gas that may cause severe injury or death by inhalation. Gas identity, odor warning, corrosivity and vapor density vary by article. Small gas quantities can still create dangerous concentrations in enclosed spaces.
Response guidance: For UN 3539, isolate damaged articles, avoid cutting/crushing/heating and identify exact gas/pressure. Use SCBA and cool exposures from protection under ERG 123.
Firefighter training notes: Training for UN 3539 should emphasize toxic-gas recognition, Zone A isolation, Level A/SCBA entry, air monitoring, source-control limits and decontamination. Use ERG 123, SDS and local SOP.
Regulatory context: Articles containing toxic gas, n.o.s. 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: Articles containing toxic gas, n.o.s. should be stored in intact approved packages away from heat, physical damage and unauthorized access, with segregation and ventilation based on exact gas identity.
UN 3539 Quick Details
Common Hazards of UN 3539
- Articles containing toxic gas, n.o.s.; damaged articles can release gas that may cause severe injury or death by inhalation.
- Gas identity, odor warning, corrosivity and vapor density vary by article.
- Small gas quantities can still create dangerous concentrations in enclosed spaces.
- Articles exposed to fire may rupture, fragment or release toxic decomposition products.
- Fire may produce toxic/corrosive smoke from gas and article materials.
- Exact gas, pressure, quantity and article design must be verified from documentation.
- Do not cut, crush, puncture or heat unknown toxic-gas articles.
Chemical Identity & Physical Properties
Various articles, devices, or equipment containing compressed or liquefied toxic gases. Physical form depends on the specific article, but contains gas under pressure that may be colorless or colored, with odor varying by gas type.
| Also known as | Toxic gas articles NOSArticles with toxic gasPackaged toxic gas itemsDevices containing toxic gas |
| Appearance | Various articles, devices, or equipment containing compressed or liquefied toxic gases. Physical form depends on the specific article, but contains gas under pressure that may be colorless or colored, with odor varying by gas type. |
| Flash Point | Not applicable (varies by contained gas) |
| Boiling Point | Not applicable (varies by contained gas) |
| Vapor Density | Varies by contained gas (potentially heavier than air) |
| Water Reactivity | Varies depending on specific toxic gas contained; some may react violently with water |
Fireground Response Guidance — UN 3539
Extinguishing Media
PPE Requirements
Use positive-pressure SCBA and chemical protective clothing; Level A may be required for damaged toxic-gas articles or unknown gas identity.
Isolation & Evacuation
First Actions for a UN 3539 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.
- 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 123, shipping papers, markings and air monitoring to set isolation, evacuation and entry decisions.
📋 Copy & Share Field Card
UN 3539 — Articles containing toxic gas, n.o.s.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.