Hazmat UN Number Lookup

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🏷️ Primary Hazard Class Filter

UN2055

Styrene monomer, stabilized

Flammable Liquids

Class 3PG III

CAS RegistryN/A

Hazchem / EAC3YE

ERG Guide Number128

49 CFR Placards & Labels

Flammable LiquidClass 3

⇩ SVG

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)

PIH Zone

—

Packaging references (49 CFR §173.xxx)

Exceptions (col 8A)

§173.150

Non-Bulk (col 8B)

§173.203

Bulk (col 8C)

§173.242

Aircraft quantity limits (col 9)

Passenger / Rail (9A)

60 L

Cargo Aircraft Only (9B)

220 L

Vessel stowage (col 10)

Location (10A)

Other codes (10B)

Special provisions (col 7 — §172.102)

387 B1 IB3 T2 TP1

Hazard Classification & Risks

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

Transport Regulations

Hazard class 3, Packing Group III. Placard/label codes: 3. Special provisions: 387, B1, IB3, T2, TP1. Packaging (49 CFR §173): exceptions §150, non-bulk §203, bulk §242. Quantity limits: passenger aircraft/rail 60 L, cargo aircraft only 220 L. Vessel stowage: C (other: 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.