UN 3416 — Chloroacetophenone, liquid
Placard: Toxic. ERG Guide 153. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 3416 is Chloroacetophenone, liquid, a toxic lachrymator associated with severe eye and respiratory irritation. It may be encountered as a riot-control or specialty chemical formulation.
Hazard overview: UN 3416 vapors and aerosols can cause intense tearing, eye pain, coughing and respiratory irritation at low concentrations. Liquid contact may injure skin and eyes, and fire can generate toxic, corrosive gases. Vapors are heavier than air and may persist in low or poorly ventilated areas.
Response guidance: For UN 3416, isolate the area, stay upwind and avoid creating aerosols. Ventilate only under incident command and with proper respiratory protection. Use alcohol-resistant foam, dry chemical, CO2 or water spray for cooling containers, and prevent contaminated runoff.
UN 3416 Quick Details
Common Hazards of UN 3416
- TOXIC and/or CORROSIVE; inhalation, ingestion or skin contact with material may cause severe injury
- Methyl bromoacetate (UN2643) is an eye irritant/lachrymator (causes flow of tears).
- Contact with molten substance may cause severe burns to skin and eyes.
- 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
- Combustible material: may burn but does not ignite readily.
- When heated, vapors may form explosive mixtures with air: indoors, outdoors and sewers explosion
Chemical Identity & Physical Properties
UN 3416 may appear as a pale yellow liquid or molten/solution form of chloroacetophenone. It has a pungent or apple-blossom-like odor and acts as a strong tear-producing agent.
| Also known as | CN gasMace2-chloroacetophenonephenacyl chloridetear gas |
| CAS Number | 532-27-4 |
| Appearance | Colorless to gray crystalline solid or pale yellow liquid with apple blossom or pungent odor. Lachrymator (causes severe tearing). |
| Flash Point | 118C (244F) |
| Boiling Point | 244-245C (471-473F) |
| Vapor Density | 5.3 (much heavier than air) |
| Water Reactivity | Slightly soluble in water; no violent reaction but hydrolyzes slowly |
Fireground Response Guidance — UN 3416
Extinguishing Media
PPE Requirements
Full-face SCBA and chemical-resistant protective clothing are required where vapors, mist or liquid contact are possible. Eye and face protection are critical because of the severe lachrymator effect.
Isolation & Evacuation
First Actions for a UN 3416 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 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 measure distance, in the downwind
📋 Copy & Share Field Card
UN 3416 — Chloroacetophenone, liquidUse for: Quick radio or face-to-face size-up. Short, structured, field-ready.
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief.
Use for: Quick text to command or incoming units. Fits in a single SMS.