☣️ UN 3450 • CLASS 6
UN 3450 — Diphenylchloroarsine, solid
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 3450 Diphenylchloroarsine, solid 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 3450 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 3450 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 3450 Quick Details
UN 3450
Product name: Diphenylchloroarsine, solid
DOT Class: 6
Placard type: Toxic
ERG Guide: 151 (check current ERG)
Initial isolation: ERG 151: Isolate spill 25m all directions; for large spills isolate 100m all directions; evacuate downwind 300m for small spills, 800m for large spills
Common Hazards of UN 3450
- 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 3450 is described as: Colorless to white or pale yellow crystalline solid. May have a faint irritating odor. Solid at room temperature.
| Also known as | Diphenylarsine chlorideDiphenylchloroarsineDAPhenarsazine chlorideClark IArsine, chlorodiphenyl- |
| CAS Number | 712-48-1 |
| Appearance | Colorless to white or pale yellow crystalline solid. May have a faint irritating odor. Solid at room temperature. |
| Flash Point | Not applicable (solid) |
| Boiling Point | 333C (631F) |
| Vapor Density | Not applicable (solid at room temperature; vapor density if volatilized would be approximately 8.6 relative to air) |
| Water Reactivity | Hydrolyzes slowly in water; may release irritating or toxic vapors |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Fireground Response Guidance — UN 3450
Extinguishing Media
Dry chemical, sand, CO2; water spray may be used to keep containers cool but avoid direct contact with material
PPE Requirements
⚠️ Level A required; full encapsulating suit with SCBA; chemical warfare agent protective gear recommended; avoid any skin contact
PPE guidance for UN 3450: Level A required; full encapsulating suit with SCBA; chemical warfare agent protective gear recommended; avoid any skin contact
Isolation & Evacuation
ERG 151: Isolate spill 25m all directions; for large spills isolate 100m all directions; evacuate downwind 300m for small spills, 800m for large spills
Always confirm protective actions with the current edition of the Emergency Response Guidebook (ERG Guide 151).
First Actions for a UN 3450 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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📋 Copy & Share Field Card
UN 3450 — Diphenylchloroarsine, solidHAZMAT RADIO NOTE — UN 3450
Product: Diphenylchloroarsine, solid
Class 6 / Toxic / ERG 151
PPE: Level A required; full encapsulating suit with SCBA; chemical warfare agent protective gear recommended; avoid any skin contact
ISOLATION: ERG 151: Isolate spill 25m all directions; for large spills isolate 100m all directions; evacuate downwind 300m for small spills, 800m for large spills
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 3450 — Diphenylchloroarsine, solid
Class: 6 | Placard: Toxic | ERG Guide: 151
Appearance: Colorless to white or pale yellow crystalline solid. May have a faint irritating odor. Solid at room temperature.
Water Reactivity: Hydrolyzes slowly in water; may release irritating or toxic vapors
Extinguishing: Dry chemical, sand, CO2; water spray may be used to keep containers cool but avoid direct contact with material
PPE: Level A required; full encapsulating suit with SCBA; chemical warfare agent protective gear recommended; avoid any skin contact
Isolation: ERG 151: Isolate spill 25m all directions; for large spills isolate 100m all directions; evacuate downwind 300m for small spills, 800m for large spills
— 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/diphenylchloroarsine-solid-un-3450 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief.
UN3450 Diphenylchloroarsine, solid Cls6 ERG151 | allfirefighter.com/hazmat/un/diphenylchloroarsine-solid-un-3450SMS / 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/diphenylchloroarsine-solid-un-3450
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Frequently Asked Questions about UN 3450
UN 3450 is Diphenylchloroarsine, solid, a Class 6 hazardous material assigned to ERG Guide 151.
UN 3450 may burn or support fire depending on the product and fire conditions. Keep ignition sources away and follow ERG 151.
Hydrolyzes slowly in water; may release irritating or toxic vapors
Level A required; full encapsulating suit with SCBA; chemical warfare agent protective gear recommended; avoid any skin contact
ERG 151: Isolate spill 25m all directions; for large spills isolate 100m all directions; evacuate downwind 300m for small spills, 800m for large spills
Dry chemical, sand, CO2; water spray may be used to keep containers cool but avoid direct contact with material
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.