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1931

UN 1931Zinc dithionite or Zinc hydrosulfite

Class 9

Miscellaneous dangerous goods

Summary

UN 1931 is the UN number for zinc dithionite or Zinc hydrosulfite. It is classed in Class 9 (miscellaneous dangerous goods) for transport. Packing group III. Emergency responders use ERG guide 171.

Emergency response

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

  • Guide171Zinc dithioniteZinc hydrosulfiteZinc hydrosulphiteHighlighted in green: see Table 1

Highlighted in green in the ERG. If there is no fire, go to ERG Table 1 for initial isolation and protective action distances, and also use the guide. If a fire is involved, use the guide's evacuation distances and protect downwind according to Table 1.

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 1931
Name
Zinc dithionite or Zinc hydrosulfite
Hazard class
Class 9: Miscellaneous dangerous goods
Packing group
III
What the class covers
Substances and articles which present a hazard during transport not covered by other classes, such as lithium batteries and environmentally hazardous substances.

U.S. Hazardous Materials Table

The entry for this number in 49 CFR 172.101.

  • UN1931Zinc dithionite or Zinc hydrosulfite

    Special provisions: IB8, IP3, T1, TP33

    Class
    9
    Packing group
    III
    Labels
    None

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 9

Class 9 covers dangerous goods that don't fit any other class, including lithium batteries, dry ice, environmentally hazardous substances, elevated-temperature materials and magnetized material.

See all Class 9 UN numbers

Check the official sources

For emergency response, packaging and quantity limits, use these: