UN/NA Number Reference
DOT Class 8 Corrosive placard

UN 1754: Chlorosulfonic acid

49 CFR 172.101 Hazardous Materials Table·ERG 2024

DOT Classification and Shipping

UN 1754 is assigned the proper shipping name Chlorosulfonic acid in the U.S. DOT Hazardous Materials Table (49 CFR 172.101). It is classified as a Class 8 Corrosive material, Packing Group I. Required label(s): 8.

Packing group indicates the degree of danger within a hazard class: PG I is high danger, PG II medium, PG III low. The proper shipping name, hazard class, UN number, and packing group together form the basic shipping description that must appear on shipping papers and, where required, on the package and placard.

Emergency Response (ERG Guide 137)

Hazards: Produce flammable gases on contact with water. May ignite on contact with water. Some react violently with water.

Fire: DO NOT use water or foam. Use dry chemical, dry sand, or soda ash.

Spill: Do not touch. Keep material dry. Move containers from water. Dike to prevent water contact.

Chemical and Physical Properties

Chlorosulfonic acid appears as a colorless to yellow colored fuming liquid with a pungent odor. Density 14.7 lb / gal. Causes severe burns. Very toxic by inhalation. Corrosive to metals.

CAS Number: 7790-94-5
Molecular Formula: ClHO3S
Molecular Weight: 116.53 g/mol
Color / Form: COLORLESS OR SLIGHTLY YELLOW LIQUID
Odor: PUNGENT
Boiling Point: 311 F
Melting Point: -112 °F (USCG, 1999)
Autoignition: Not flammable (USCG, 1999)
Specific Gravity: 1.75 (sinks in water)
Vapor Pressure: 1.55 mmHg
Vapor Density: 4.02 (heavier than air)
Water Solubility: /COMMON SOLVENTS INCLUDE/ LIQUID SULFUR DIOXIDE, PYRIDINE, & DICHLOROETHANE.

Regulatory Data

CERCLA RQ (40 CFR 302.4)
1000 lb

A release of this material at or above its CERCLA reportable quantity (1000 lb) requires immediate notification to the National Response Center at 800-424-8802.

Special Provisions

49 CFR 172.102 special provision codes for this entry: 2, B9, B10, B14, B32, T20, TP2, TP38, TP45. These codes modify the general requirements (packaging, quantity limits, exceptions) for this specific material. Look up each code in 49 CFR 172.102 for the full text.

Need the full interactive record? Open UN 1754 in the SpillNerd lookup tool for the live database entry with placard graphics, GHS pictograms, full segregation tables, and synonym search. For another material, use the UN number and chemical lookup.

Reference data compiled from the DOT Hazardous Materials Table (49 CFR 172.101), the 2024 Emergency Response Guidebook, and public chemical databases (PubChem, NIOSH, EPA). Always verify the correct shipping description against the current regulation and the manufacturer's SDS Section 14 before shipping.