UNunnums
2681

UN 2681Caesium hydroxide solution

Class 8

Corrosives

Summary

UN 2681 is the UN number for caesium hydroxide solution. It is classed in Class 8 (corrosives) for transport. Packing group II or III, depending on the form. Emergency responders use ERG guide 154.

Emergency response

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

  • Guide154Caesium hydroxide, solutionCesium hydroxide, solution

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 2681
Name
Caesium hydroxide solution
Hazard class
Class 8: Corrosives
Packing group
II, III
What the class covers
Substances which can damage living tissue or other goods and materials on contact.

U.S. Hazardous Materials Table

2 entries share this number in 49 CFR 172.101, by name, packing group or where the shipment is going.

  • UN2681Caesium hydroxide solution

    Special provisions: B2, IB2, T7, TP2

    Class
    8
    Packing group
    II
    Labels
    8

  • UN2681Caesium hydroxide solution

    Special provisions: IB3, T4, TP1

    Class
    8
    Packing group
    III
    Labels
    8

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: