Hazmat UN Number Lookup

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🏷️ Primary Hazard Class Filter

UN2921

Corrosive solids, flammable, n.o.s.

Corrosives

Class 8 (Primary)Class 4.1 (Subsidiary)PG I

CAS RegistryN/A (Mixture)

Hazchem / EAC2X

ERG Guide Number154

49 CFR Placards & Labels

CorrosiveClass 8

⇩ SVG

Flammable SolidClass 4.1

⇩ SVG

Not listed as a Reportable Quantity (RQ) hazardous substance under §172.101 Appendix A.

Not listed as a Marine Pollutant under §172.101 Appendix B.

Regulatory Facts

Packing Group

Symbols (col 1)

Labels (col 6)

8, 4.1

PIH Zone

—

Packaging references (49 CFR §173.xxx)

Exceptions (col 8A)

None

Non-Bulk (col 8B)

§173.211

Bulk (col 8C)

§173.242

Aircraft quantity limits (col 9)

Passenger / Rail (9A)

1 kg

Cargo Aircraft Only (9B)

25 kg

Vessel stowage (col 10)

Location (10A)

Other codes (10B)

12, 25

Special provisions (col 7 — §172.102)

IB6 T6 TP33

Hazard Classification & Risks

Class 8 — Corrosive. Causes full-thickness skin destruction or severely corrodes steel/aluminum (49 CFR §173.136). Packing Group I — great danger.

Transport Regulations

Hazard class 8, Packing Group I. Placard/label codes: 8, 4.1. Special provisions: IB6, T6, TP33. Packaging (49 CFR §173): exceptions §None, non-bulk §211, bulk §242. Quantity limits: passenger aircraft/rail 1 kg, cargo aircraft only 25 kg. Vessel stowage: B (other: 12, 25). 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.

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