UN 1754 — Chlorosulphonic acid (with or without sulphur trioxide)
Placard: Corrosive. ERG Guide 137. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 1754 is Chlorosulphonic acid (with or without sulphur trioxide), a hazardous material assigned to ERG Guide 137. Responders should verify the exact product with shipping papers, package markings and SDS before close action.
Hazard overview: UN 1754 presents corrosive, toxic, flammable or reactive hazards depending on the product and incident conditions. Use ERG, SDS and incident command to set isolation, PPE and control actions.
Response guidance: For a UN 1754 incident, responders should verify the product with shipping papers, package markings, SDS and ERG Guide 137. 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 1754 should emphasize toxic/corrosive exposure routes, water or oxidizer incompatibility where applicable, air monitoring, PPE selection, decontamination and runoff containment. Use ERG 137, SDS and local SOP.
Regulatory context: Chlorosulphonic acid (with or without sulphur trioxide) 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: Chlorosulphonic acid (with or without sulphur trioxide) should be stored in tightly closed compatible containers in a secure, cool, dry, well-ventilated hazardous-material area according to SDS and local procedures.
UN 1754 Quick Details
Common Hazards of UN 1754
- CORROSIVE material; inhalation, ingestion or skin/eye contact may cause severe injury.
- Fire may produce irritating, corrosive and/or toxic gases.
- Runoff may be corrosive and may pollute waterways.
- Containers may rupture or fail when heated.
- Specific hazards depend on the exact product, concentration and SDS.
Chemical Identity & Physical Properties
Colorless to pale yellow fuming liquid with a pungent, acrid odor. Extremely corrosive and reacts violently with moisture in air, producing dense white fumes of hydrochloric acid and sulfuric acid mist.
| Also known as | chlorosulfuric acidsulfuric chlorohydrinmonochlorosulfuric acidsulfurochloridic acid |
| CAS Number | 7790-94-5 |
| Appearance | Colorless to pale yellow fuming liquid with a pungent, acrid odor. Extremely corrosive and reacts violently with moisture in air, producing dense white fumes of hydrochloric acid and sulfuric acid mist. |
| Flash Point | Not applicable (non-flammable liquid) |
| Boiling Point | 151-152C (304-306F) |
| Vapor Density | 4.0 (heavier than air) |
| Water Reactivity | Reacts violently with water, generating intense heat and toxic/corrosive fumes (HCl, SO2, H2SO4). Never apply water directly. |
Fireground Response Guidance — UN 1754
Extinguishing Media
PPE Requirements
Use positive-pressure SCBA for vapor, mist, fire or confined-space exposure. Chemical-resistant gloves, eye/face protection and protective clothing should be selected from SDS to prevent skin and eye contact.
Isolation & Evacuation
First Actions for a UN 1754 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 or gas and avoid skin or eye contact.
- 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 137, shipping papers, SDS, air monitoring and incident command for protective actions.
📋 Copy & Share Field Card
UN 1754 — Chlorosulphonic acid (with or without suUse 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.