UN 1953 — Compressed gas, poisonous, flammable, n.o.s. (Inhalation Hazard Zone A)
Placard: Toxic Gas. ERG Guide 119. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 1953 is Compressed gas, poisonous, flammable, n.o.s. (Inhalation Hazard Zone A), a toxic inhalation hazard Zone A flammable gas entry assigned to ERG Guide 119. It requires both toxic gas and ignition-control tactics.
Hazard overview: UN 1953 presents fatal inhalation, flammable gas, frostbite/burn, cylinder rupture and downwind exposure hazards.
Response guidance: For a UN 1953 incident, verify the product with shipping papers, container markings, SDS and ERG Guide 119. Establish incident command, isolate the area, stay upwind, control ignition or downwind hazards, cool exposed containers from a protected distance when appropriate and base entry decisions on monitoring and local SOP.
Firefighter training notes: Training for UN 1953 should emphasize toxic inhalation hazard procedures, ERG Table 1 use, gas monitoring, Level A entry decisions, cylinder control, evacuation and decontamination. Use ERG 119, SDS and local SOP.
Regulatory context: Compressed gas, poisonous, flammable, n.o.s. (Inhalation Hazard Zone A) is regulated as a hazardous material for transportation and emergency response purposes. Requirements for storage, workplace exposure, emergency planning, spill reporting and waste handling 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: Compressed gas, poisonous, flammable, n.o.s. (Inhalation Hazard Zone A) cylinders or containers should be secured in a cool, ventilated gas storage area away from heat, flames, ignition sources, oxidizers where incompatible and physical damage. Follow SDS and local code for gas detection and emergency shutoff.
UN 1953 Quick Details
Common Hazards of UN 1953
- TOXIC INHALATION HAZARD Zone A and FLAMMABLE compressed gas; inhalation may be fatal.
- May ignite by heat, sparks or flames and may form explosive mixtures with air.
- Gas or liquefied gas contact may cause frostbite, chemical burns or severe injury depending on composition.
- Vapors may be heavier than air and collect in low or confined areas.
- Cylinders exposed to fire may vent toxic/flammable gas, rupture or rocket.
- Fire may produce irritating, corrosive and/or toxic gases.
- Exact toxicity, corrosivity and reactivity depend on the gas named on shipping papers and SDS.
Chemical Identity & Physical Properties
Generic classification for compressed gases that are both poisonous and flammable. Physical state is gas under pressure; may be liquefied. Color and odor vary depending on specific gas composition.
| Also known as | Poisonous compressed gas n.o.s.Toxic flammable gas n.o.s.Compressed toxic flammable gasInhalation hazard gas Zone A |
| Appearance | Generic classification for compressed gases that are both poisonous and flammable. Physical state is gas under pressure; may be liquefied. Color and odor vary depending on specific gas composition. |
| Flash Point | Not applicable (flammable gas) |
| Boiling Point | Not applicable (varies by specific gas composition) |
| Vapor Density | Varies by composition (typically heavier than air for Zone A materials) |
| Water Reactivity | Varies by specific gas; some may react, others inert with water |
Fireground Response Guidance — UN 1953
Extinguishing Media
PPE Requirements
Use positive-pressure SCBA and fully encapsulating chemical protective clothing for close entry or unknown concentrations. Level A may be needed; avoid all skin contact and follow toxic inhalation hazard procedures.
Isolation & Evacuation
First Actions for a UN 1953 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.
- Treat the incident as a serious inhalation hazard; use Table 1/protective-action guidance where applicable.
- Avoid breathing gas, vapor, smoke or mist and avoid skin or eye contact.
- Eliminate ignition sources if safe and keep gas or vapor 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 release area and expand the perimeter for fire involvement, cylinder heating, vapor accumulation, unknown gas identity or downwind exposure.
- Use ERG Guide 119, shipping papers, SDS, air monitoring and incident command for protective actions.
📋 Copy & Share Field Card
UN 1953 — Compressed gas, poisonous, flammable, n.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.