Hazmat UN Number Lookup

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🏷️ Primary Hazard Class Filter

UN2256

Cyclohexene

Flammable Liquids

Class 3PG II

CAS RegistryN/A

Hazchem / EAC3YE

ERG Guide Number128

49 CFR Placards & Labels

Flammable LiquidClass 3

⇩ 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)

PIH Zone

—

Packaging references (49 CFR §173.xxx)

Exceptions (col 8A)

§173.150

Non-Bulk (col 8B)

§173.202

Bulk (col 8C)

§173.242

Aircraft quantity limits (col 9)

Passenger / Rail (9A)

5 L

Cargo Aircraft Only (9B)

60 L

Vessel stowage (col 10)

Location (10A)

Other codes (10B)

—

Special provisions (col 7 — §172.102)

IB2 T4 TP1

Hazard Classification & Risks

Class 3 — Flammable liquid. Flash point ≤60°C (140°F) (49 CFR §173.120). Packing Group II — medium danger.

Transport Regulations

Hazard class 3, Packing Group II. Placard/label codes: 3. Special provisions: IB2, T4, TP1. Packaging (49 CFR §173): exceptions §150, non-bulk §202, bulk §242. Quantity limits: passenger aircraft/rail 5 L, cargo aircraft only 60 L. Vessel stowage: E. 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.