☣️ UN 3493 • CLASS 6
UN 3493 — Poisonous by inhalation liquid, corrosive, flammable, n.o.s. (Inhalation Hazard Zone B)
Placard: Toxic (Inhalation Hazard). ERG Guide 131. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
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⚠️ 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 3493 covers poisonous-by-inhalation liquid, n.o.s. in Inhalation Hazard Zone B, with additional corrosive flammable hazards.
Hazard overview: The primary risk is severe inhalation toxicity. The liquid may also be flammable and corrosive, and vapors can collect in low or confined areas.
Response guidance: Isolate immediately, eliminate ignition sources, stay upwind, prevent runoff, and use foam, dry chemical, or CO2 as appropriate for the exact product.
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UN 3493 Quick Details
UN 3493
Product name: Poisonous by inhalation liquid, corrosive, flammable, n.o.s. (Inhalation Hazard Zone B)
DOT Class: 6
Placard type: Toxic (Inhalation Hazard)
ERG Guide: 131 (check current ERG)
Initial isolation: ERG 131: Isolate spill area immediately for at least 100m in all directions; for large spills consider initial evacuation 300m downwind; inhalation hazard zone B requires 2km downwind evacuation if large release
Common Hazards of UN 3493
- TOXIC; may be fatal if inhaled, ingested or absorbed through skin.
- Inhalation or contact with some of these materials will irritate or burn skin and eyes.
- Methyl chloroacetate (UN2295) is an eye irritant/lachrymator (causes flow of tears).
- Fire will produce irritating, corrosive and/or toxic gases.
- Vapors may cause dizziness or asphyxiation, especially when in closed or confined areas.
- Runoff from fire control or dilution water may cause environmental contamination.
- HIGHLY FLAMMABLE: Will be easily ignited by heat, sparks or flames.
- Vapors may form explosive mixtures with air.
Chemical Identity & Physical Properties
The substance is typically a corrosive liquid with irritating or toxic vapors at room temperature.
| Also known as | Toxic inhalation hazard liquidTIH liquid corrosive flammablePIH liquid Zone BPoisonous corrosive flammable liquid NOS |
| Appearance | Variable properties depending on specific chemical; typically a corrosive liquid with irritating or toxic vapors at room temperature. May have distinctive odor depending on composition. |
| Flash Point | Variable, but flammable (typically below 60C/140F) |
| Boiling Point | Variable depending on specific substance |
| Vapor Density | Typically heavier than air (>1) |
| Water Reactivity | May react with water; corrosive properties suggest caution with water application |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Fireground Response Guidance — UN 3493
Extinguishing Media
Use alcohol-resistant foam or dry chemical; water spray may increase vapor hazard but can be used for cooling containers
PPE Requirements
⚠️ Level A required for entry; SCBA with full face piece mandatory; chemical-resistant suit required due to corrosive and toxic inhalation hazard
Level A with fully encapsulating suit and SCBA is recommended because of the inhalation hazard.
Isolation & Evacuation
ERG 131: Isolate spill area immediately for at least 100m in all directions; for large spills consider initial evacuation 300m downwind; inhalation hazard zone B requires 2km downwind evacuation if large release
Always confirm protective actions with the current edition of the Emergency Response Guidebook (ERG Guide 131).
First Actions for a UN 3493 Incident
- CALL 911. Then call the emergency response number on the shipping paper, if available.
- 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 50 meters (150 feet) in all directions.
- For highlighted materials: see Table 1 - Initial Isolation and Protective Action Distances.
- For non-highlighted materials, increase the downwind precautionary distance as conditions require.
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📋 Copy & Share Field Card
UN 3493 — Poisonous by inhalation liquid, corrosivHAZMAT RADIO NOTE — UN 3493
Product: Poisonous by inhalation liquid, corrosive, flammable, n.o.s. (Inhalation Hazard Zone B)
Class 6 / Toxic (Inhalation Hazard) / ERG 131
PPE: Level A required for entry; SCBA with full face piece mandatory; chemical-resistant suit required due to corrosive and toxic inhalation hazard
ISOLATION: ERG 131: Isolate spill area immediately for at least 100m in all directions; for large spills consider initial evacuation 300m downwind; inhalation hazard zone B requires 2km downwind evacuation if large release
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 3493 — Poisonous by inhalation liquid, corrosive, flammable, n.o.s. (Inhalation Hazard Zone B)
Class: 6 | Placard: Toxic (Inhalation Hazard) | ERG Guide: 131
Appearance: Variable properties depending on specific chemical; typically a corrosive liquid with irritating or toxic vapors at room temperature. May have distinctive odor depending on composition.
Water Reactivity: May react with water; corrosive properties suggest caution with water application
Extinguishing: Use alcohol-resistant foam or dry chemical; water spray may increase vapor hazard but can be used for cooling containers
PPE: Level A required for entry; SCBA with full face piece mandatory; chemical-resistant suit required due to corrosive and toxic inhalation hazard
Isolation: ERG 131: Isolate spill area immediately for at least 100m in all directions; for large spills consider initial evacuation 300m downwind; inhalation hazard zone B requires 2km downwind evacuation if large release
— Key Hazards —
• TOXIC; may be fatal if inhaled, ingested or absorbed through skin.
• Inhalation or contact with some of these materials will irritate or burn skin and eyes.
• Methyl chloroacetate (UN2295) is an eye irritant/lachrymator (causes flow of tears).
— First Actions —
• CALL 911. Then call the emergency response number on the shipping paper, if available.
• Keep unauthorized personnel away.
• Stay upwind, uphill and/or upstream.
• Ventilate closed spaces before entering, but only if properly trained and equipped.
SOURCE: allfirefighter.com/hazmat/un/poisonous-by-inhalation-liquid-un-3493 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief.
UN3493 Poisonous by inhalation liquid, corrosive, flammable, n.o.s. (Inhalation Hazard Zone B) Cls6 ERG131 | allfirefighter.com/hazmat/un/poisonous-by-inhalation-liquid-un-3493SMS / 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/poisonous-by-inhalation-liquid-un-3493
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Frequently Asked Questions about UN 3493
Yes. It has flammable liquid hazards in addition to inhalation toxicity.
Water reactivity depends on the specific product; avoid direct contact until shipping papers or SDS identify the material.
Level A with fully encapsulating suit and SCBA is recommended because of the inhalation hazard.
Treat as an extreme inhalation hazard, isolate the area, stay upwind, and evacuate downwind as directed by ERG and incident command.
UN 3493 is assigned to ERG Guide 131 for initial emergency response guidance.
Inhalation Hazard Zone B indicates a severe toxic inhalation risk; Zone A is more severe than Zone B.
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.