☣️ UN 3440 • CLASS 6
UN 3440 — Selenium compound, liquid, n.o.s.
Placard: Toxic. ERG Guide 151. 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 3440 Selenium compound, liquid, n.o.s. is assigned to ERG Guide 151. The exact risk depends on the shipment form, concentration and SDS, but responders should verify shipping papers before committing crews.
Hazard overview: Primary hazards for UN 3440 include: Highly toxic, may be fatal if inhaled, ingested or absorbed through skin.; Avoid any skin contact.; Fire may produce irritating, corrosive and/or toxic gases. Control ignition sources, avoid direct contact and keep personnel upwind.
Response guidance: For a UN 3440 incident, isolate the area, deny entry, stay upwind and use ERG Guide 151 with the shipping papers or SDS. Use compatible extinguishing media only and prevent contaminated runoff from spreading.
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UN 3440 Quick Details
UN 3440
Product name: Selenium compound, liquid, n.o.s.
DOT Class: 6
Placard type: Toxic
ERG Guide: 151 (check current ERG)
Initial isolation: ERG 151: isolate spill 25-50m all directions; evacuate immediate area; consider 300m+ for large spills or fire
Common Hazards of UN 3440
- Highly toxic, may be fatal if inhaled, ingested or absorbed through skin.
- Avoid any skin contact.
- Fire may produce irritating, corrosive and/or toxic gases.
- Runoff from fire control or dilution water may be corrosive and/or toxic and cause environmental contamination.
- Non-combustible, substance itself does not burn but may decompose upon heating to produce corrosive.
- Containers may explode when heated.
- Runoff may pollute waterways.
Chemical Identity & Physical Properties
UN 3440 is described as: Varies depending on specific compound; typically clear to colored liquid with variable odor. Physical properties depend on the selenium compound formulation.
| Also known as | Selenium compound solutionLiquid selenium derivativeSelenium-containing liquidOrganoselenium compound liquid |
| Appearance | Varies depending on specific compound; typically clear to colored liquid with variable odor. Physical properties depend on the selenium compound formulation. |
| Flash Point | Varies by compound - consult SDS for specific formulation |
| Boiling Point | Varies by compound - consult SDS for specific formulation |
| Vapor Density | Varies by compound - typically heavier than air |
| Water Reactivity | Generally no violent reaction, but may hydrolyze or decompose in water depending on compound |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Fireground Response Guidance — UN 3440
Extinguishing Media
Alcohol-resistant foam, dry chemical, CO2; avoid water spray for certain compounds
PPE Requirements
⚠️ Level A or B required; full-face SCBA, chemical-resistant suit; avoid all skin contact due to high toxicity and absorption risk
PPE guidance for UN 3440: Level A or B required; full-face SCBA, chemical-resistant suit; avoid all skin contact due to high toxicity and absorption risk
Isolation & Evacuation
ERG 151: isolate spill 25-50m all directions; evacuate immediate area; consider 300m+ for large spills or fire
Always confirm protective actions with the current edition of the Emergency Response Guidebook (ERG Guide 151).
First Actions for a UN 3440 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.
- Isolate spill or leak area in all directions for at least 50 meters (150 feet) for liquids and at least 25 meters.
- For highlighted materials: see Table 1 - Initial Isolation and Protective Action Distances.
- For non-highlighted materials, increase the immediate precautionary distance in the downwind direction as conditions require.
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UN 3440 — Selenium compound, liquid, n.o.s.HAZMAT RADIO NOTE — UN 3440
Product: Selenium compound, liquid, n.o.s.
Class 6 / Toxic / ERG 151
PPE: Level A or B required; full-face SCBA, chemical-resistant suit; avoid all skin contact due to high toxicity and absorption risk
ISOLATION: ERG 151: isolate spill 25-50m all directions; evacuate immediate area; consider 300m+ for large spills or fire
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 3440 — Selenium compound, liquid, n.o.s.
Class: 6 | Placard: Toxic | ERG Guide: 151
Appearance: Varies depending on specific compound; typically clear to colored liquid with variable odor. Physical properties depend on the selenium compound formulation.
Water Reactivity: Generally no violent reaction, but may hydrolyze or decompose in water depending on compound
Extinguishing: Alcohol-resistant foam, dry chemical, CO2; avoid water spray for certain compounds
PPE: Level A or B required; full-face SCBA, chemical-resistant suit; avoid all skin contact due to high toxicity and absorption risk
Isolation: ERG 151: isolate spill 25-50m all directions; evacuate immediate area; consider 300m+ for large spills or fire
— Key Hazards —
• Highly toxic, may be fatal if inhaled, ingested or absorbed through skin.
• Avoid any skin contact.
• Fire may produce irritating, corrosive and/or toxic gases.
— First Actions —
• 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.
• Isolate spill or leak area in all directions for at least 50 meters (150 feet) for liquids and at least 25 meters.
SOURCE: allfirefighter.com/hazmat/un/selenium-compound-liquid-n-un-3440 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief.
UN3440 Selenium compound, liquid, n.o.s. Cls6 ERG151 | allfirefighter.com/hazmat/un/selenium-compound-liquid-n-un-3440SMS / 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/selenium-compound-liquid-n-un-3440
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Frequently Asked Questions about UN 3440
UN 3440 is Selenium compound, liquid, n.o.s., a Class 6 hazardous material assigned to ERG Guide 151.
UN 3440 may burn or support fire depending on the product and fire conditions. Keep ignition sources away and follow ERG 151.
Generally no violent reaction, but may hydrolyze or decompose in water depending on compound
Level A or B required; full-face SCBA, chemical-resistant suit; avoid all skin contact due to high toxicity and absorption risk
ERG 151: isolate spill 25-50m all directions; evacuate immediate area; consider 300m+ for large spills or fire
Alcohol-resistant foam, dry chemical, CO2; avoid water spray for certain compounds
Several entries are n.o.s. or mixture categories, so the exact health, fire and reactivity hazards depend on the specific shipped product.
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.