UN3191: Self-heating solid
As listed: Self-heating solid, toxic, inorganic, n.o.s.
UN3191 appears 2 times in the Hazardous Materials Table (49 CFR §172.101). Hazard class 4.2, packing group II, III.
All §172.101 entries for UN3191
| Proper shipping name | Class | PG | Labels |
|---|---|---|---|
| Self-heating solid, toxic, inorganic, n.o.s. | 4.2 | II | 4.2, 6.1 |
| Self-heating solid, toxic, inorganic, n.o.s. | 4.2 | III | 4.2, 6.1 |
Open any entry for packaging sections, special provisions, air limits and vessel stowage.
What it means
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
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 UN3191 in the current PHMSA Emergency Response Guidebook.
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Common questions about UN3191
What is UN3191?
UN3191 is the identification number for Self-heating solid, toxic, inorganic, n.o.s. in the DOT Hazardous Materials Table (49 CFR §172.101).
What hazard class is UN3191?
UN3191 is listed under hazard class 4.2 (spontaneously combustible).
What packing group is UN3191?
Packing group for UN3191: II, III. Where several rows exist, the packing group that fits your material decides which row applies.