UNunnums
3474

UN 34741-Hydroxybenzotriazole, anhydrous, wetted with not less than 20% water, by mass

Proper shipping name: 1-Hydroxybenzotriazole, monohydrate

Division 4.1

Flammable solids

Summary

UN 3474 is the UN number for 1-Hydroxybenzotriazole, anhydrous, wetted with not less than 20% water, by mass. It is classed in Division 4.1 (flammable solids) of Class 4 for transport. Packing group I. Emergency responders use ERG guide 113.

Emergency response

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

  • Guide1131-Hydroxybenzotriazole, monohydrate

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 3474
Name
1-Hydroxybenzotriazole, anhydrous, wetted with not less than 20% water, by mass
Hazard class
Class 4: Flammable solids
Division
4.1: Flammable solids
Packing group
I
What the class covers
Flammable solids, self-reactive substances and solid desensitized explosives.

U.S. Hazardous Materials Table

The entry for this number in 49 CFR 172.101.

  • UN34741-Hydroxybenzotriazole, monohydrate

    Special provisions: N90

    Class
    4.1
    Packing group
    I
    Labels
    4.1

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 4

Class 4 covers flammable solids and other substances that can catch fire. Division 4.1 is flammable solids and self-reactive substances, 4.2 is substances that can spontaneously combust in air, and 4.3 is substances that give off flammable gas when wet.

See all Class 4 UN numbers

Check the official sources

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