☣️ UN 3505 • CLASS 2
UN 3505 — Chemical under pressure, flammable, corrosive, n.o.s.
Placard: Flammable Gas. ERG Guide 118. 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 3505 is Chemical under pressure, flammable, corrosive, n.o.s., a pressurized hazardous material assigned to ERG Guide 118. The exact contents should be verified from shipping papers and the SDS before close-range action.
Hazard overview: Primary hazards include corrosive burns, fire or vapor ignition, container rupture. Chemical under pressure, flammable, corrosive, 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 3505 incident, establish incident command, isolate the area, stay upwind and uphill, keep unauthorized personnel away, verify shipping papers/SDS and follow ERG 118. Use extinguishing, cooling, containment and decontamination tactics only when compatible with the material and local SOP.
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UN 3505 Quick Details
UN 3505
Product name: Chemical under pressure, flammable, corrosive, n.o.s.
DOT Class: 2
Placard type: Flammable Gas
ERG Guide: 118 (check current ERG)
Initial isolation: ERG 118: Initial isolation 100m all directions; Protective action distance 300m downwind daytime, 800m nighttime for small spills; larger spills require greater distances
Common Hazards of UN 3505
- EXTREMELY FLAMMABLE.
- May be ignited by heat, sparks or flames.
- May form explosive mixtures with air.
- Vapors from liquefied gas are initially heavier than air and spread along ground.
- Vapors may travel to source of ignition and flash back.
- Some of these materials may react violently with water.
- Cylinders exposed to fire may vent and release flammable gas through pressure relief devices.
- Containers may explode when heated.
Chemical Identity & Physical Properties
Variable appearance depending on specific chemical; pressurized gas or liquefied gas mixture that is both flammable and corrosive. May be colorless to colored with various odors.
| Also known as | Chemical under pressure flammable corrosive NOSCompressed chemical flammable corrosivePressurized flammable corrosive chemicalUN3505 |
| Appearance | Variable appearance depending on specific chemical; pressurized gas or liquefied gas mixture that is both flammable and corrosive. May be colorless to colored with various odors. |
| Flash Point | Not applicable (pressurized flammable gas) |
| Boiling Point | Variable depending on specific chemical composition |
| Vapor Density | Variable, typically heavier than air when released |
| Water Reactivity | May react depending on corrosive component; avoid water contact due to corrosive properties |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Fireground Response Guidance — UN 3505
Extinguishing Media
Dry chemical, CO2; water spray for cooling only from distance; foam may be ineffective due to pressurized nature
PPE Requirements
⚠️ Level B minimum; SCBA required; chemical-resistant suit due to corrosive properties; full face protection mandatory
Level B minimum; SCBA required; chemical-resistant suit due to corrosive properties; full face protection mandatory
Isolation & Evacuation
ERG 118: Initial isolation 100m all directions; Protective action distance 300m downwind daytime, 800m nighttime for small spills; larger spills require greater distances
Always confirm protective actions with the current edition of the Emergency Response Guidebook (ERG Guide 118).
First Actions for a UN 3505 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 3505 — Chemical under pressure, flammable, corrHAZMAT RADIO NOTE — UN 3505
Product: Chemical under pressure, flammable, corrosive, n.o.s.
Class 2 / Flammable Gas / ERG 118
PPE: Level B minimum; SCBA required; chemical-resistant suit due to corrosive properties; full face protection mandatory
ISOLATION: ERG 118: Initial isolation 100m all directions; Protective action distance 300m downwind daytime, 800m nighttime for small spills; larger spills require greater distances
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 3505 — Chemical under pressure, flammable, corrosive, n.o.s.
Class: 2 | Placard: Flammable Gas | ERG Guide: 118
Appearance: Variable appearance depending on specific chemical; pressurized gas or liquefied gas mixture that is both flammable and corrosive. May be colorless to colored with various odors.
Water Reactivity: May react depending on corrosive component; avoid water contact due to corrosive properties
Extinguishing: Dry chemical, CO2; water spray for cooling only from distance; foam may be ineffective due to pressurized nature
PPE: Level B minimum; SCBA required; chemical-resistant suit due to corrosive properties; full face protection mandatory
Isolation: ERG 118: Initial isolation 100m all directions; Protective action distance 300m downwind daytime, 800m nighttime for small spills; larger spills require greater distances
— Key Hazards —
• EXTREMELY FLAMMABLE.
• May be ignited by heat, sparks or flames.
• May form explosive mixtures with air.
— 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-3505 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief.
UN3505 Chemical under pressure, flammable, corrosive, n.o.s. Cls2 ERG118 | allfirefighter.com/hazmat/un/chemical-under-pressure-flammable-un-3505SMS / 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-3505
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Frequently Asked Questions about UN 3505
UN 3505 is Chemical under pressure, flammable, corrosive, n.o.s., assigned to ERG Guide 118.
ERG Guide 118 applies for initial isolation, protective actions and first response guidance.
Yes. Chemical under pressure, flammable, corrosive, 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.
Pressurized containers may rupture, rocket or vent hazardous gas when heated or damaged.
Level B minimum; SCBA required; chemical-resistant suit due to corrosive properties; full face protection mandatory.
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.