☣️ UN 3504 • CLASS 2
UN 3504 — Chemical under pressure, flammable, poisonous, n.o.s.
Placard: Flammable Gas. ERG Guide 119. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
🚒☣️
⚠️ Verification required:
Broad or variable material category; verify exact product, SDS and shipping papers.
⚠️ This page is a quick-reference aid. For real incidents: stage upwind, isolate, deny entry, request Hazmat early, and consult the current ERG + SOP/SOG.
UN 3504 is Chemical under pressure, flammable, poisonous, n.o.s., a pressurized hazardous material assigned to ERG Guide 119. The exact contents should be verified from shipping papers and the SDS before close-range action.
Hazard overview: Primary hazards include toxic exposure, corrosive burns, fire or vapor ignition, container rupture. Chemical under pressure, flammable, poisonous, n.o.s. may release irritating, toxic or corrosive vapors when heated, spilled or involved in fire, so avoid contact, inhalation and incompatible materials.
Response guidance: For a UN 3504 incident, establish incident command, isolate the area, stay upwind and uphill, keep unauthorized personnel away, verify shipping papers/SDS and follow ERG 119. Use extinguishing, cooling, containment and decontamination tactics only when compatible with the material and local SOP.
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UN 3504 Quick Details
UN 3504
Product name: Chemical under pressure, flammable, poisonous, n.o.s.
DOT Class: 2
Placard type: Flammable Gas
ERG Guide: 119 (check current ERG)
Initial isolation: ERG 119: Small spill isolate 100m all directions. Large spill isolate 800m all directions, evacuate 1600m downwind during day or 3200m at night.
Common Hazards of UN 3504
- TOXIC; may be fatal if inhaled or absorbed through skin. Some may cause severe skin burns and
- Contact with gas or liquefied gas may cause burns, severe injury and/or frostbite.
- Fire will produce irritating, corrosive and/or toxic gases.
- Runoff from fire control or dilution water may cause environmental contamination.
- Flammable; may be ignited by heat, sparks or flames.
- May form explosive mixtures with air. Ethylene oxide (UN1040) may react explosively even in the
- Those substances designated with a (P) may polymerize explosively when heated or involved in a fire.
- Vapors from liquefied gas are initially heavier than air and spread along ground.
Chemical Identity & Physical Properties
Compressed or liquefied gas or chemical mixture under pressure. May be colorless or colored depending on specific chemical. Flammable and toxic with potentially irritating or pungent odor.
| Also known as | Chemical under pressure, flammable, toxic, n.o.s.Compressed chemical, flammable, poisonousPressurized flammable toxic chemical |
| Appearance | Compressed or liquefied gas or chemical mixture under pressure. May be colorless or colored depending on specific chemical. Flammable and toxic with potentially irritating or pungent odor. |
| Flash Point | Not applicable (compressed gas) |
| Boiling Point | Varies depending on specific chemical composition |
| Vapor Density | Typically heavier than air when released |
| Water Reactivity | Variable; depends on specific chemical composition. Use caution with water application. |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Fireground Response Guidance — UN 3504
Extinguishing Media
Water spray to cool containers, dry chemical, CO2. Avoid direct water stream on leak.
PPE Requirements
⚠️ Level A required for unknown composition. Full-face SCBA, chemical-resistant suit with gloves. Gas-tight suit for high concentrations or confined spaces.
Level A required for unknown composition. Full-face SCBA, chemical-resistant suit with gloves. Gas-tight suit for high concentrations or confined spaces.
Isolation & Evacuation
ERG 119: Small spill isolate 100m all directions. Large spill isolate 800m all directions, evacuate 1600m downwind during day or 3200m at night.
Always confirm protective actions with the current edition of the Emergency Response Guidebook (ERG Guide 119).
First Actions for a UN 3504 Incident
- Keep unauthorized personnel away.
- Stay upwind, uphill and/or upstream.
- Ventilate closed spaces before entering, but only if properly trained and equipped.
- Isolate spill or leak area for at least 100 meters (330 feet) in all directions.
- For highlighted materials: see Table 1 - Initial Isolation and Protective Action Distances.
- For non-highlighted materials: increase the immediate precautionary measure distance, in the downwind
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📋 Copy & Share Field Card
UN 3504 — Chemical under pressure, flammable, poisHAZMAT RADIO NOTE — UN 3504
Product: Chemical under pressure, flammable, poisonous, n.o.s.
Class 2 / Flammable Gas / ERG 119
PPE: Level A required for unknown composition. Full-face SCBA, chemical-resistant suit with gloves. Gas-tight suit for high concentrations or confined spaces.
ISOLATION: ERG 119: Small spill isolate 100m all directions. Large spill isolate 800m all directions, evacuate 1600m downwind during day or 3200m at night.
ACTION: Stage upwind · Isolate · Deny entry · Request HazmatRADIO
Use for: Quick radio or face-to-face size-up. Short, structured, field-ready.
=== IC HAZMAT BRIEFING ===
UN 3504 — Chemical under pressure, flammable, poisonous, n.o.s.
Class: 2 | Placard: Flammable Gas | ERG Guide: 119
Appearance: Compressed or liquefied gas or chemical mixture under pressure. May be colorless or colored depending on specific chemical. Flammable and toxic with potentially irritating or pungent odor.
Water Reactivity: Variable; depends on specific chemical composition. Use caution with water application.
Extinguishing: Water spray to cool containers, dry chemical, CO2. Avoid direct water stream on leak.
PPE: Level A required for unknown composition. Full-face SCBA, chemical-resistant suit with gloves. Gas-tight suit for high concentrations or confined spaces.
Isolation: ERG 119: Small spill isolate 100m all directions. Large spill isolate 800m all directions, evacuate 1600m downwind during day or 3200m at night.
— Key Hazards —
• TOXIC; may be fatal if inhaled or absorbed through skin. Some may cause severe skin burns and
• Contact with gas or liquefied gas may cause burns, severe injury and/or frostbite.
• Fire will produce irritating, corrosive and/or toxic gases.
— First Actions —
• Keep unauthorized personnel away.
• Stay upwind, uphill and/or upstream.
• Ventilate closed spaces before entering, but only if properly trained and equipped.
• Isolate spill or leak area for at least 100 meters (330 feet) in all directions.
SOURCE: allfirefighter.com/hazmat/un/chemical-under-pressure-flammable-un-3504 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief.
UN3504 Chemical under pressure, flammable, poisonous, n.o.s. Cls2 ERG119 | allfirefighter.com/hazmat/un/chemical-under-pressure-flammable-un-3504SMS / 160 CHAR
Use for: Quick text to command or incoming units. Fits in a single SMS.
⚠️ Quick-reference only. Always use current ERG + SOP/SOG for incident-specific actions.
Page: https://allfirefighter.com/hazmat/un/chemical-under-pressure-flammable-un-3504
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Frequently Asked Questions about UN 3504
UN 3504 is Chemical under pressure, flammable, poisonous, n.o.s., assigned to ERG Guide 119.
ERG Guide 119 applies for initial isolation, protective actions and first response guidance.
Yes. Chemical under pressure, flammable, poisonous, n.o.s. can present a fire, combustion or vapor ignition hazard; keep it away from heat, sparks and flames.
Yes. Avoid skin, eye and respiratory contact; corrosive vapors or liquids can cause severe burns.
Yes. Inhalation, ingestion, skin absorption or contaminated runoff may create serious health hazards.
Pressurized containers may rupture, rocket or vent hazardous gas when heated or damaged.
Sources (high level): DOT/PHMSA marking & class concepts + ERG usage principles.
This page does not reproduce ERG guide text—always consult the current ERG for incident-specific protective actions.