UNunnums
2546

UN 2546Titanium powder, dry

Division 4.2

Spontaneously combustible

Summary

UN 2546 is the UN number for titanium powder, dry. It is classed in Division 4.2 (spontaneously combustible) of Class 4 for transport. Packing group I, II or III, depending on the form. Emergency responders use ERG guide 135.

Emergency response

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

  • Guide135Titanium powder, dry

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 2546
Name
Titanium powder, dry
Hazard class
Class 4: Flammable solids
Division
4.2: Spontaneously combustible
Packing group
I, II, III
What the class covers
Substances liable to spontaneous combustion.

U.S. Hazardous Materials Table

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

  • UN2546Titanium powder, dry

    Special provisions: W31

    Class
    4.2
    Packing group
    I
    Labels
    4.2

  • UN2546Titanium powder, dry

    Special provisions: A19, A20, IB6, IP2, N5, N34, T3, TP33, W31

    Class
    4.2
    Packing group
    II
    Labels
    4.2

  • UN2546Titanium powder, dry

    Special provisions: B135, IB8, IP21, T1, TP33, W31

    Class
    4.2
    Packing group
    III
    Labels
    4.2

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: