UN 1741 — Boron trichloride
Placard: Toxic Gas. ERG Guide 125. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 1741 is Boron trichloride, a toxic corrosive gas assigned to ERG Guide 125. It reacts violently with water or moist air and can release dense corrosive hydrogen chloride fumes.
Hazard overview: UN 1741 presents toxic gas, corrosive fume, frostbite and water-reactivity hazards. Heavy vapor can move into low areas and heated cylinders may rupture or vent.
Response guidance: For a UN 1741 incident, responders should verify the product with shipping papers, package markings, SDS and ERG Guide 125. Establish incident command, isolate the area, stay upwind, prevent incompatible contact, control runoff and choose entry or fire-control actions based on monitoring, SDS and local SOP.
Firefighter training notes: Training for UN 1741 should emphasize toxic/corrosive exposure routes, water or oxidizer incompatibility where applicable, air monitoring, PPE selection, decontamination and runoff containment. Use ERG 125, SDS and local SOP.
Regulatory context: Boron trichloride is regulated as a hazardous material for transportation and emergency response purposes. Transportation, workplace exposure, spill reporting, waste handling, storage and environmental requirements may vary by concentration, formulation, 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: Boron trichloride should be stored in tightly closed compatible containers in a cool, dry, well-ventilated area away from water, moisture, bases, oxidizers/reducing agents where incompatible, heat and unauthorized access. Protect containers from corrosion, leakage and contamination.
UN 1741 Quick Details
Common Hazards of UN 1741
- TOXIC and CORROSIVE gas or liquefied gas; inhalation may be fatal.
- Reacts violently with water or moist air, releasing heat and corrosive hydrogen chloride fumes.
- Contact with gas or liquefied gas may cause severe burns, injury and/or frostbite.
- Vapors are heavier than air and may spread along the ground into low or confined areas.
- Fire or heat may produce irritating, corrosive and/or toxic gases.
- Cylinders or containers may rupture or vent when heated.
- Runoff or water spray may carry corrosive contamination.
Chemical Identity & Physical Properties
Colorless gas or fuming liquid with a pungent, irritating odor. Exists as a gas at room temperature but may be shipped as a liquefied compressed gas.
| Also known as | Boron chlorideTrichloroboraneTrichloroboronBCl3 |
| CAS Number | 10294-34-5 |
| Appearance | Colorless gas or fuming liquid with a pungent, irritating odor. Exists as a gas at room temperature but may be shipped as a liquefied compressed gas. |
| Flash Point | Not applicable (non-flammable gas) |
| Boiling Point | 12.5C (54.5F) |
| Vapor Density | 4.0 (heavier than air) |
| Water Reactivity | Reacts violently with water producing toxic and corrosive fumes of hydrochloric acid and boric acid. Do not use water. |
Fireground Response Guidance — UN 1741
Extinguishing Media
PPE Requirements
Use positive-pressure SCBA and chemical protective clothing selected by hazmat specialists. Level A may be needed for close entry, unknown concentrations or liquefied gas/vapor contact because toxic, corrosive and heavy-vapor hazards may be severe.
Isolation & Evacuation
First Actions for a UN 1741 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 low areas, basements, trenches and confined spaces where heavy vapor or gas may accumulate.
- Avoid breathing vapors, fumes, dust, mist or gas and avoid skin or eye contact.
- Keep water and moisture away from released product 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, gas, dust, fire involvement, water reaction or unknown concentration is present.
- Use ERG Guide 125, shipping papers, SDS, air monitoring and incident command for protective actions.
📋 Copy & Share Field Card
UN 1741 — Boron trichlorideUse 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.