UN identification number

UN1326: Hafnium powder, wetted

As listed: Hafnium powder, wetted with not less than 25 percent water (a visible excess of water must be present) (a) mechanically produced, particle size less than 53 microns; (b) chemically produced, particle size less than 840 microns

UN1326 appears 1 time in the Hazardous Materials Table (49 CFR §172.101). Hazard class 4.1, packing group II.

ID numberUN1326

Hazard class4.1

Packing groupII

Label codes4.1

All §172.101 entries for UN1326

Proper shipping name	Class	PG	Labels
Hafnium powder, wetted with not less than 25 percent water (a visible excess of water must be present) (a) mechanically produced, particle size less than 53 microns; (b) chemically produced, particle size less than 840 microns	4.1	II	4.1

Open any entry for packaging sections, special provisions, air limits and vessel stowage.

What it means

4.1

Class 4.1 — Flammable solid. Solids that ignite readily or can cause fire through friction, plus self-reactive and desensitized explosive materials.

Packing group ranks danger within the class: PG II = medium danger.

Label codes (column 6): 4.1 → Flammable solid label.

UN numbers are recognized for international and domestic transport.

Example basic description

UN1326, Hafnium powder, wetted, 4.1, PG II

Proper shipping name shown without the table's italic descriptive text. Order per §172.202: ID number, proper shipping name, hazard class, packing group. Example only — add technical names, “RQ”, quantities and other elements your shipment requires.

What to check next

Match the name. Compare your SDS Section 14 to the proper shipping names above and pick the row with your packing group.
Read the special provisions on the entry page (§172.102) — they can add limits or exceptions.
Check packaging — the entry page lists the Part 173 sections for exceptions, non-bulk and bulk.
Labels & placards. Placarding depends on class and quantity — see Table 1 vs Table 2.
Emergency response. Find the response guide for UN1326 in the current PHMSA Emergency Response Guidebook.

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Common questions about UN1326

What is UN1326?

UN1326 is the identification number for Hafnium powder, wetted in the DOT Hazardous Materials Table (49 CFR §172.101).

What hazard class is UN1326?

UN1326 is listed under hazard class 4.1 (flammable solid).

What packing group is UN1326?

Packing group for UN1326: II. Where several rows exist, the packing group that fits your material decides which row applies.

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← UN1325 All UN numbers All Class 4.1 materials UN1328 →

Source: Hazardous Materials Table (49 CFR §172.101), eCFR.gov — current as of Oct 23, 2026. View the official table. Reference only — verify current requirements before shipping.