Hazmat UN Number Lookup

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🏷️ Primary Hazard Class Filter

UN1561

Arsenic trioxide

Toxic Substances

Class 6.1PG II

CAS RegistryN/A

Hazchem / EAC2X

ERG Guide Number153

49 CFR Placards & Labels

Toxic (Poison)Class 6.1

⇩ SVG

Reportable Quantity — 1 lb (0.454 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

Symbols (col 1)

—

Labels (col 6)

6.1

PIH Zone

—

Packaging references (49 CFR §173.xxx)

Exceptions (col 8A)

§173.153

Non-Bulk (col 8B)

§173.212

Bulk (col 8C)

§173.242

Aircraft quantity limits (col 9)

Passenger / Rail (9A)

25 kg

Cargo Aircraft Only (9B)

100 kg

Vessel stowage (col 10)

Location (10A)

Other codes (10B)

—

Special provisions (col 7 — §172.102)

IB8 IP2 IP4 T3 TP33

Hazard Classification & Risks

Class 6.1 — Toxic (poison). Liable to cause death or serious injury if swallowed, inhaled or absorbed through skin (49 CFR §173.132). Packing Group II — medium danger.

Transport Regulations

Hazard class 6.1, Packing Group II. Placard/label codes: 6.1. Special provisions: IB8, IP2, IP4, T3, TP33. Packaging (49 CFR §173): exceptions §153, non-bulk §212, bulk §242. Quantity limits: passenger aircraft/rail 25 kg, cargo aircraft only 100 kg. Vessel stowage: A. 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.