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UN identification number

UN1931: Zinc dithionite or Zinc hydrosulfite

UN1931 appears 1 time in the Hazardous Materials Table (49 CFR §172.101). Hazard class 9, packing group III.

ID numberUN1931
Hazard class9
Packing groupIII
Label codesNone

All §172.101 entries for UN1931

Proper shipping nameClassPGLabels
Zinc dithionite or Zinc hydrosulfite9IIINone

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

What it means

9
Class 9 — Miscellaneous hazardous material. Materials that present a hazard during transport but don't meet another class — for example lithium batteries, dry ice, and environmentally hazardous substances.

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

Label codes (column 6): No hazard label required (label code “None”).

UN numbers are recognized for international and domestic transport.

Example basic description

UN1931, Zinc dithionite or Zinc hydrosulfite, 9, PG III

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 UN1931 in the current PHMSA Emergency Response Guidebook.
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Common questions about UN1931

What is UN1931?

UN1931 is the identification number for Zinc dithionite or Zinc hydrosulfite in the DOT Hazardous Materials Table (49 CFR §172.101).

What hazard class is UN1931?

UN1931 is listed under hazard class 9 (miscellaneous hazardous material).

What packing group is UN1931?

Packing group for UN1931: III. Where several rows exist, the packing group that fits your material decides which row applies.

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← UN1929All UN numbersAll Class 9 materialsUN1932 →
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.