Hazmat UN Number Lookup

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🏷️ Primary Hazard Class Filter

UN2834

Phosphorous acid

Corrosives

Class 8PG III

CAS RegistryN/A

Hazchem / EAC2X

ERG Guide Number137

49 CFR Placards & Labels

CorrosiveClass 8

⇩ 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

III

Symbols (col 1)

—

Labels (col 6)

PIH Zone

—

Packaging references (49 CFR §173.xxx)

Exceptions (col 8A)

§173.154

Non-Bulk (col 8B)

§173.213

Bulk (col 8C)

§173.240

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)

25, 53, 58

Special provisions (col 7 — §172.102)

IB8 IP3 T1 TP33

Hazard Classification & Risks

Class 8 — Corrosive. Causes full-thickness skin destruction or severely corrodes steel/aluminum (49 CFR §173.136). Packing Group III — minor danger.

Transport Regulations

Hazard class 8, Packing Group III. Placard/label codes: 8. Special provisions: IB8, IP3, T1, TP33. Packaging (49 CFR §173): exceptions §154, non-bulk §213, bulk §240. Quantity limits: passenger aircraft/rail 25 kg, cargo aircraft only 100 kg. Vessel stowage: A (other: 25, 53, 58). 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.