Hazmat UN Number Lookup

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🏷️ Primary Hazard Class Filter

UN1341

Phosphorus sesquisulfide, free from yellow or white phosphorus

Flammable Solids

Class 4.1PG II

CAS RegistryN/A

Hazchem / EAC1Z

ERG Guide Number133

49 CFR Placards & Labels

Flammable SolidClass 4.1

⇩ 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.

Severe Marine Pollutant (S.M.P.)

Marine-pollutant mark (§172.322) required for bulk packages by vessel; IMDG segregation and stowage rules apply. S.M.P. status may extend the mark to non-bulk single packages.

Regulatory Facts

Packing Group

Symbols (col 1)

—

Labels (col 6)

4.1

PIH Zone

—

Packaging references (49 CFR §173.xxx)

Exceptions (col 8A)

§173.151

Non-Bulk (col 8B)

§173.212

Bulk (col 8C)

§173.240

Aircraft quantity limits (col 9)

Passenger / Rail (9A)

15 kg

Cargo Aircraft Only (9B)

50 kg

Vessel stowage (col 10)

Location (10A)

Other codes (10B)

Special provisions (col 7 — §172.102)

A20 IB4 N34 T3 TP33 W31

Hazard Classification & Risks

Class 4.1 — Flammable solid, self-reactive substance or desensitized explosive; readily combustible or may cause fire through friction (49 CFR §173.124). Packing Group II — medium danger.

Transport Regulations

Hazard class 4.1, Packing Group II. Placard/label codes: 4.1. Special provisions: A20, IB4, N34, T3, TP33, W31. Packaging (49 CFR §173): exceptions §151, non-bulk §212, bulk §240. Quantity limits: passenger aircraft/rail 15 kg, cargo aircraft only 50 kg. Vessel stowage: B (other: 74). 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.