☣️ UN 1754 • CLASS 8
Chlorosulphonic acid (with or without sulphur trioxide)
Placard: Corrosive. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
🚒☣️
⚠️ This page is a quick-reference aid. For real incidents: stage upwind, isolate, deny entry, request Hazmat early, and consult the current ERG + SOP/SOG.
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Quick details
UN 1754
Class: 8
Placard type: Corrosive
ERG: Guide 137 (check current ERG)
Isolation: ERG 137: Isolate spill area 50m in all directions. For large spill, isolate 800m downwind. Evacuate immediate area and stay upwind.
Chemical & Response Details
| 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. |
| Extinguishing | Dry chemical, soda ash, lime. Do NOT use water, foam, or CO2. |
| PPE | ⚠️ Level A required for spill response. Full encapsulating chemical protective suit, SCBA, butyl rubber or Viton gloves. Acid-resistant boots. |
| Isolation | ERG 137: Isolate spill area 50m in all directions. For large spill, isolate 800m downwind. Evacuate immediate area and stay upwind. |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Common hazards (high level)
- CORROSIVE and/or TOXIC; inhalation, ingestion or contact (skin, eyes) with vapors, dusts or substance
- Fire will produce irritating, corrosive and/or toxic gases.
- Reaction with water may generate much heat that will increase the concentration of fumes in the air.
- Contact with molten substance may cause severe burns to skin and eyes.
- Runoff from fire control or dilution water may cause environmental contamination.
- EXCEPT FOR ACETIC ANHYDRIDE (UN1715), THAT IS FLAMMABLE, some of these materials may
- May ignite combustibles (wood, paper, oil, clothing, etc.).
- Substance will react with water (some violently), releasing corrosive and/or toxic gases and runoff.
First actions (field-minded)
- CALL 911. Then call emergency response telephone number on shipping paper. If shipping paper
- 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
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UN 1754 — Chlorosulphonic acid (with or without su HAZMAT RADIO NOTE — UN 1754
Product: Chlorosulphonic acid (with or without sulphur trioxide)
Class 8 / Corrosive / ERG 137
PPE: Level A required for spill response. Full encapsulating chemical protective suit, SCBA, butyl rubber or Viton gloves. Acid-resistant boots.
ISOLATION: ERG 137: Isolate spill area 50m in all directions. For large spill, isolate 800m downwind. Evacuate immediate area and stay upwind.
ACTION: Stage upwind · Isolate · Deny entry · Request HazmatRADIO
Use for: Quick radio or face-to-face size-up. Short, structured, field-ready.
=== IC HAZMAT BRIEFING ===
UN 1754 — Chlorosulphonic acid (with or without sulphur trioxide)
Class: 8 | Placard: Corrosive | ERG Guide: 137
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.
Water Reactivity: Reacts violently with water, generating intense heat and toxic/corrosive fumes (HCl, SO2, H2SO4). Never apply water directly.
Extinguishing: Dry chemical, soda ash, lime. Do NOT use water, foam, or CO2.
PPE: Level A required for spill response. Full encapsulating chemical protective suit, SCBA, butyl rubber or Viton gloves. Acid-resistant boots.
Isolation: ERG 137: Isolate spill area 50m in all directions. For large spill, isolate 800m downwind. Evacuate immediate area and stay upwind.
— Key Hazards —
• CORROSIVE and/or TOXIC; inhalation, ingestion or contact (skin, eyes) with vapors, dusts or substance
• Fire will produce irritating, corrosive and/or toxic gases.
• Reaction with water may generate much heat that will increase the concentration of fumes in the air.
— First Actions —
• CALL 911. Then call emergency response telephone number on shipping paper. If shipping paper
• Keep unauthorized personnel away.
• Stay upwind, uphill and/or upstream.
• Ventilate closed spaces before entering, but only if properly trained and equipped.
SOURCE: allfirefighter.com/hazmat/un/1754 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief. Full chemical + response details.
UN1754 Chlorosulphonic acid (with or without sulphur trioxide) Cls8 ERG137 | allfirefighter.com/hazmat/un/1754SMS / 160 CHAR
Use for: Quick text to command or incoming units. Fits in a single SMS. Includes link to full page.
⚠️ Quick-reference only. Always use current ERG + SOP/SOG for incident-specific actions. Page: https://allfirefighter.com/hazmat/un/1754
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FAQ
CORROSIVE and/or TOXIC; inhalation, ingestion or contact (skin, eyes) with vapors, dusts or substance Fire will produce irritating, corrosive and/or toxic gases. Reaction with water may generate much heat that will increase the concentration of fumes in the air. Contact with molten substance may cause severe burns to skin and eyes. Runoff from fire control or dilution water may cause environmental contamination. EXCEPT FOR ACETIC ANHYDRIDE (UN1715), THAT IS FLAMMABLE, some of these materials may May ignite combustibles (wood, paper, oil, clothing, etc.). Substance will react with water (some violently), releasing corrosive and/or toxic gases and runoff.
CALL 911. Then call emergency response telephone number on shipping paper. If shipping paper Keep unauthorized personnel away. Stay upwind, uphill and/or upstream.
Level A required for spill response. Full encapsulating chemical protective suit, SCBA, butyl rubber or Viton gloves. Acid-resistant boots.
No. This is a training/quick-reference aid only. Always consult the current ERG Guide 137 and your department SOP/SOG for incident-specific protective actions.
Sources (high level): DOT/PHMSA marking & class concepts + ERG usage principles. This page does not reproduce ERG guide text—always consult the current ERG for incident-specific protective actions.