Hazmat UN Number Lookup

Search hazardous materials database, check safety specifications, and view Emergency Response guides.

🏷️ Primary Hazard Class Filter

UN2521

Diketene, stabilized

Toxic Substances

Class 6.1 (Primary)Class 3 (Subsidiary)PG I

CAS RegistryN/A

Hazchem / EAC2X

ERG Guide Number153

49 CFR Placards & Labels

Toxic (Poison)Class 6.1

⇩ SVG

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)

6.1, 3

PIH Zone

—

Packaging references (49 CFR §173.xxx)

Exceptions (col 8A)

None

Non-Bulk (col 8B)

§173.227

Bulk (col 8C)

§173.244

Aircraft quantity limits (col 9)

Passenger / Rail (9A)

Forbidden

Cargo Aircraft Only (9B)

Forbidden

Vessel stowage (col 10)

Location (10A)

Other codes (10B)

25, 26, 27, 40

Special provisions (col 7 — §172.102)

2 387 B9 B14 B32 T20 TP2 TP13 TP38 TP45

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 I — great danger.

Transport Regulations

Hazard class 6.1, Packing Group I. Placard/label codes: 6.1, 3. Special provisions: 2, 387, B9, B14, B32, T20, TP2, TP13, TP38, TP45. Packaging (49 CFR §173): exceptions §None, non-bulk §227, bulk §244. Quantity limits: passenger aircraft/rail Forbidden, cargo aircraft only Forbidden. Vessel stowage: D (other: 25, 26, 27, 40). 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.

Regulatory Facts

Packing Group

Symbols (col 1)

—

Labels (col 6)

6.1, 3

PIH Zone

—

Packaging references (49 CFR §173.xxx)

Exceptions (col 8A)

None

Non-Bulk (col 8B)

§173.227

Bulk (col 8C)

§173.244

Aircraft quantity limits (col 9)

Passenger / Rail (9A)

Forbidden

Cargo Aircraft Only (9B)

Forbidden

Vessel stowage (col 10)

Location (10A)

Other codes (10B)

25, 26, 27, 40

Special provisions (col 7 — §172.102)

2 387 B9 B14 B32 T20 TP2 TP13 TP38 TP45

Source & sourcing note

Emergency-response content is drawn from the 2024 Emergency Response Guidebook (ERG), a joint publication of PHMSA, Transport Canada, and Mexico’s SCT.