UNunnums
1829

UN 1829Sulfur trioxide, inhibited or Sulfur trioxide, stabilized

Proper shipping name: Sulfur trioxide, stabilized

Class 8

Corrosives

Summary

UN 1829 is the UN number for sulfur trioxide, inhibited or Sulfur trioxide, stabilized. It is classed in Class 8 (corrosives) for transport. Packing group I. Emergency responders use ERG guide 137.

Emergency response

The Emergency Response Guidebook (ERG2024) guide for this number:

  • Guide137Sulfur trioxide, stabilizedSulphur trioxide, stabilizedHighlighted in green: see Table 1

Highlighted in green in the ERG. If there is no fire, go to ERG Table 1 for initial isolation and protective action distances, and also use the guide. If a fire is involved, use the guide's evacuation distances and protect downwind according to Table 1.

From the 2024 Emergency Response Guidebook (ERG2024), published by U.S. Department of Transportation, PHMSA. Read the full guide in the ERG or on CAMEO Chemicals.

Identification

UN number
UN 1829
Name
Sulfur trioxide, inhibited or Sulfur trioxide, stabilized
Hazard class
Class 8: Corrosives
Packing group
I
What the class covers
Substances which can damage living tissue or other goods and materials on contact.

U.S. Hazardous Materials Table

The entry for this number in 49 CFR 172.101.

  • UN1829Sulfur trioxide, stabilized

    • Name, class and packing group fixed by regulation

    Special provisions: 2, 387, B9, B14, B32, B49, B77, N34, T20, TP4, TP13, TP25, TP26, TP38, TP45

    Class
    8
    Packing group
    I
    Labels
    8, 6.1

From the eCFR edition of 49 CFR 172.101 dated 2026-10-05 (section last amended 2026-09-08). The eCFR is an editorial compilation, not the official legal edition. Read the current table.

About Class 8

Class 8 covers corrosive substances such as acids, alkalis and battery fluid, which can destroy skin or corrode metal on contact.

See all Class 8 UN numbers

Check the official sources

For emergency response, packaging and quantity limits, use these: