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UN identification number

UN3128: Self-heating solid, toxic, organic, n.o.s

UN3128 appears 2 times in the Hazardous Materials Table (49 CFR §172.101). Hazard class 4.2, packing group II, III.

ID numberUN3128
Hazard class4.2
Packing groupII, III
Label codes4.2, 6.1

All §172.101 entries for UN3128

Proper shipping nameClassPGLabels
Self-heating solid, toxic, organic, n.o.s4.2II4.2, 6.1
Self-heating solid, toxic, organic, n.o.s4.2III4.2, 6.1

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

What it means

4.2
Class 4.2 — Spontaneously combustible. Materials that can heat up and ignite on their own in air.

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

Label codes (column 6): 4.2, 6.1 → Spontaneously combustible label + subsidiary Poison / Toxic label.

UN numbers are recognized for international and domestic transport.

Example basic description

UN3128, Self-heating solid, toxic, organic, n.o.s, 4.2, 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

  1. Match the name. Compare your SDS Section 14 to the proper shipping names above and pick the row with your packing group.
  2. Read the special provisions on the entry page (§172.102) — they can add limits or exceptions.
  3. Check packaging — the entry page lists the Part 173 sections for exceptions, non-bulk and bulk.
  4. Labels & placards. Placarding depends on class and quantity — see Table 1 vs Table 2.
  5. Emergency response. Find the response guide for UN3128 in the current PHMSA Emergency Response Guidebook.
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Common questions about UN3128

What is UN3128?

UN3128 is the identification number for Self-heating solid, toxic, organic, n.o.s in the DOT Hazardous Materials Table (49 CFR §172.101).

What hazard class is UN3128?

UN3128 is listed under hazard class 4.2 (spontaneously combustible).

What packing group is UN3128?

Packing group for UN3128: II, III. Where several rows exist, the packing group that fits your material decides which row applies.

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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.