Hazmat UN Number Lookup
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🏷️ Primary Hazard Class Filter
UN1931
Zinc dithionite or Zinc hydrosulfite
Miscellaneous Dangerous Goods
Class 9 (Primary)Class None (Subsidiary)PG III
CAS RegistryN/A
Hazchem / EAC2Z
ERG Guide Number171
49 CFR Placards & Labels
Reportable Quantity — 1,000 lb (454 kg)
Any release meeting or exceeding this amount must be reported to the National Response Center at 1-800-424-8802 under 40 CFR 302.6 and 49 CFR 171.15.
Not listed as a Marine Pollutant under §172.101 Appendix B.
Regulatory Facts
Packing Group
III
Symbols (col 1)
—
Labels (col 6)
None
PIH Zone
—
Packaging references (49 CFR §173.xxx)
Exceptions (col 8A)
§173.155
Non-Bulk (col 8B)
§173.204
Bulk (col 8C)
§173.240
Aircraft quantity limits (col 9)
Passenger / Rail (9A)
100 kg
Cargo Aircraft Only (9B)
200 kg
Vessel stowage (col 10)
Location (10A)
A
Other codes (10B)
13, 26, 123
Hazard Classification & Risks
Class 9 — Miscellaneous dangerous goods that present a transport hazard not covered by other classes (e.g. elevated-temperature, environmentally hazardous, lithium batteries) (49 CFR §173.140). Packing Group III — minor danger.
Transport Regulations
Hazard class 9, Packing Group III. Placard/label codes: None. Special provisions: IB8, IP3, T1, TP33. Packaging (49 CFR §173): exceptions §155, non-bulk §204, bulk §240. Quantity limits: passenger aircraft/rail 100 kg, cargo aircraft only 200 kg. Vessel stowage: A (other: 13, 26, 123). Classified per 49 CFR §172.101.
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Source & sourcing note
Regulatory data mirrors the U.S. 49 CFR §172.101 Hazardous Materials Table and companion columns (packaging, quantity limits, vessel stowage, special provisions) as published by the U.S. Pipeline and Hazardous Materials Safety Administration (PHMSA).
Emergency-response content is drawn from the 2024 Emergency Response Guidebook (ERG), a joint publication of PHMSA, Transport Canada, and Mexico’s SCT.
The U.S. edition of the ERG and all U.S. federal regulations are public-domain works under 17 U.S.C. §105. Descriptions on this page are plain-English paraphrases; for any compliance decision, consult the authoritative text on eCFR Title 49 and the ERG at PHMSA.dot.gov. “ERG™” is attributed to PHMSA / Transport Canada / SCT and used nominatively.