Hazmat UN Number Lookup

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🏷️ Primary Hazard Class Filter

UN2305

Nitrobenzenesulfonic acid

Corrosives

Class 8PG II

CAS Registry71-43-2

Hazchem / EAC2X

ERG Guide Number137

49 CFR Placards & Labels

CorrosiveClass 8

⇩ SVG

Reportable Quantity — 10 lb (4.54 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.

Source: 40 CFR §302.4 CERCLA list, matched by CAS. DOT §172.101 Appendix A lists the same substance under a different chemical name; RQ value is identical by regulatory design.

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)

§173.154

Non-Bulk (col 8B)

§173.202

Bulk (col 8C)

§173.242

Aircraft quantity limits (col 9)

Passenger / Rail (9A)

1 L

Cargo Aircraft Only (9B)

30 L

Vessel stowage (col 10)

Location (10A)

Other codes (10B)

53, 58

Special provisions (col 7 — §172.102)

B2 B4 IB8 IP2 IP4 T3 TP33

Hazard Classification & Risks

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

Transport Regulations

Hazard class 8, Packing Group II. Placard/label codes: 8. Special provisions: B2, B4, IB8, IP2, IP4, T3, TP33. Packaging (49 CFR §173): exceptions §154, non-bulk §202, bulk §242. Quantity limits: passenger aircraft/rail 1 L, cargo aircraft only 30 L. Vessel stowage: A (other: 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.