UN 1555 — Arsenic bromide
Placard: Toxic. ERG Guide 151. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 1555 is Arsenic bromide, a highly toxic and corrosive arsenic halide assigned to ERG Guide 151. It fumes in moist air and can release corrosive hydrogen halide fumes plus toxic arsenic contamination.
Hazard overview: UN 1555 presents toxic arsenic exposure, corrosive fume and water-reactivity hazards. Water contact can generate heat and dense toxic/corrosive fumes; responders should keep runoff controlled and avoid direct contact.
Response guidance: For a UN 1555 incident, responders should verify the product with shipping papers, package markings, SDS and ERG Guide 151. Establish incident command, isolate the area, stay upwind, prevent dust or vapor exposure, control runoff and choose entry or cleanup actions based on monitoring, SDS and local SOP.
Firefighter training notes: Training for UN 1555 should emphasize water-reactive toxic/corrosive fumes, arsenic contamination, air monitoring, dry-agent selection and decontamination. Common errors include applying water directly and entering fuming areas without SCBA. Use ERG 151, SDS and hazmat SOP.
Regulatory context: Arsenic bromide 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: Arsenic bromide should be stored in tightly closed compatible containers in a cool, dry, well-ventilated secure area away from water, moisture, acids/bases where incompatible, oxidizers and heat. Protect containers from corrosion, leaks and unauthorized access.
UN 1555 Quick Details
Common Hazards of UN 1555
- HIGHLY TOXIC and CORROSIVE; inhalation, ingestion or skin contact may cause severe or fatal injury.
- Reacts with water or moist air to release corrosive hydrogen halide fumes and toxic arsenic compounds.
- Reaction with water may generate heat and dense irritating fumes.
- Vapors or fumes are heavier than air and may collect in low or confined areas.
- Fire may produce irritating, corrosive and/or toxic gases.
- Runoff may spread toxic and corrosive contamination.
- Containers may rupture or fail when heated.
Chemical Identity & Physical Properties
Colorless to pale yellow crystalline solid or lumps. Fumes in moist air with an acrid, irritating odor.
| Also known as | Arsenic tribromideArsenous bromideTribromoarsineAsBr3 |
| CAS Number | 7784-33-0 |
| Appearance | Colorless to pale yellow crystalline solid or lumps. Fumes in moist air with an acrid, irritating odor. |
| Flash Point | Not applicable (non-combustible solid) |
| Boiling Point | 221C (430F) |
| Vapor Density | Not applicable (solid, but vapors heavier than air when heated) |
| Water Reactivity | Reacts with water to produce toxic arsenic compounds and hydrogen bromide fumes |
Fireground Response Guidance — UN 1555
Extinguishing Media
PPE Requirements
Use positive-pressure SCBA and chemical-resistant protective clothing for vapor, fume, liquid or unknown exposure. Level A may be needed for close entry because both toxic arsenic and corrosive hydrogen halide fumes are possible.
Isolation & Evacuation
First Actions for a UN 1555 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 or mist and avoid all skin or eye contact.
- Keep water and moisture away from the released material unless incident command confirms a compatible cooling or control use.
- Do not touch or walk through spilled material unless properly trained and wearing appropriate protective equipment.
- 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, fire involvement or unknown concentration is present.
- Use ERG Guide 151, shipping papers, SDS, air monitoring and incident command for protective actions.
📋 Copy & Share Field Card
UN 1555 — Arsenic bromideUse 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.