UN 1698 — Diphenylamine chloroarsine
Placard: Toxic. ERG Guide 154. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 1698 is Diphenylamine chloroarsine, a toxic arsenical irritant agent assigned to ERG Guide 154. Aerosol, smoke or dust exposure can cause severe eye and respiratory irritation plus arsenic contamination.
Hazard overview: UN 1698 presents toxic arsenic, lachrymator/aerosol and contaminated-runoff hazards. Fire or hydrolysis may create arsenic-containing residues and corrosive decomposition products.
Response guidance: For a UN 1698 incident, responders should verify the product with shipping papers, package markings, SDS and ERG Guide 154. Establish incident command, isolate the area, stay upwind, prevent dust, vapor or aerosol exposure, control runoff and choose entry or cleanup actions based on monitoring, SDS and local SOP.
Firefighter training notes: Training for UN 1698 should emphasize arsenic dust/aerosol exposure, contamination control, SCBA use, runoff containment and decontamination. Use ERG 154, SDS and local SOP.
Regulatory context: Diphenylamine chloroarsine is regulated as a toxic arsenic hazardous material. Transportation, workplace exposure, spill reporting, waste handling, storage and environmental requirements may vary by compound, concentration, quantity and jurisdiction. Verify current requirements through shipping papers, SDS, facility documents and applicable DOT, OSHA, EPA, NFPA, state or local authority guidance.
Storage & handling: Diphenylamine chloroarsine should be stored in tightly closed compatible containers in a secure, cool, dry, well-ventilated toxic-material area away from food, incompatible chemicals, heat and unauthorized access. Prevent dust release, leaks and contaminated runoff.
UN 1698 Quick Details
Common Hazards of UN 1698
- TOXIC arsenical irritant/lachrymator agent; inhalation, ingestion or skin contact may cause severe injury.
- Aerosol, dust or smoke can cause intense eye, respiratory and nausea-type irritation.
- Hydrolysis or fire may produce toxic arsenic-containing residues and corrosive decomposition products.
- Vapors, aerosols or smoke may accumulate in low or poorly ventilated areas.
- Fire may produce irritating, corrosive and/or toxic gases.
- Runoff may spread arsenic contamination.
- Avoid dust, smoke, aerosol and all unnecessary skin contact.
Chemical Identity & Physical Properties
Yellow-green to dark green crystalline solid with a peppery or garlic-like odor. Odorless when pure. May appear as a smoke or aerosol when dispersed.
| Also known as | AdamsiteDMPhenarsazine chloride10-Chloro-5,10-dihydrophenarsazineDiphenylaminechloroarsine |
| CAS Number | 712-48-1 |
| Appearance | Yellow-green to dark green crystalline solid with a peppery or garlic-like odor. Odorless when pure. May appear as a smoke or aerosol when dispersed. |
| Flash Point | Not applicable (non-flammable solid) |
| Boiling Point | 410°C (770°F) with decomposition |
| Vapor Density | Not applicable (solid) |
| Water Reactivity | Hydrolyzes slowly in water; no violent reaction but may release toxic arsenic compounds over time |
Fireground Response Guidance — UN 1698
Extinguishing Media
PPE Requirements
Use positive-pressure SCBA and chemical protective clothing for aerosol, dust, smoke or unknown exposure. Level A may be needed for close entry; decontamination should address arsenic-containing residues.
Isolation & Evacuation
First Actions for a UN 1698 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.
- Avoid breathing vapors, fumes, dust, mist, aerosol or smoke and avoid all skin or eye contact.
- Do not touch or walk through spilled material unless properly trained and wearing appropriate protective equipment.
- Avoid creating dust clouds or spreading contaminated liquid, powder, solution, runoff or debris.
- Ventilate closed spaces before entering, but only if properly trained, equipped, monitored and authorized by incident command.
- Isolate the spill or leak area and expand the perimeter if vapor, dust, aerosol, fire involvement or unknown concentration is present.
- Use ERG Guide 154, shipping papers, SDS, air monitoring and incident command for protective actions.
📋 Copy & Share Field Card
UN 1698 — Diphenylamine chloroarsineUse 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.