UN 3456: Nitrosylsulfuric acid, solid

DOT Classification and Shipping

UN 3456 is assigned the proper shipping name Nitrosylsulfuric acid, solid in the U.S. DOT Hazardous Materials Table (49 CFR 172.101). It is classified as a Class 8 Corrosive material, Packing Group II. Required label(s): 8.

Packing group indicates the degree of danger within a hazard class: PG I is high danger, PG II medium, PG III low. The proper shipping name, hazard class, UN number, and packing group together form the basic shipping description that must appear on shipping papers and, where required, on the package and placard.

Emergency Response (ERG Guide 157)

Hazards: TOXIC and/or CORROSIVE. Reacts with water. Non-combustible in themselves.

Fire: DO NOT use water. Dry chemical, CO2, dry sand.

Spill: Do not touch. Keep material dry.

Chemical and Physical Properties

Shipped in solution with sulfuric acid (solutions are usually 40% nitrosylsulfuric acid and 54% sulfuric acid (Hawley)). Solution is a straw-colored oily liquid with a sharp odor. When pure, a crystalline solid decomposing at 73 °C. Very irritating to skin and eyes. Used to make dyes and other chemicals.

Special Provisions

49 CFR 172.102 special provision codes for this entry: IB8, IP2, IP4, T3, TP33. These codes modify the general requirements (packaging, quantity limits, exceptions) for this specific material. Look up each code in 49 CFR 172.102 for the full text.

Need the full interactive record? Open UN 3456 in the SpillNerd lookup tool for the live database entry with placard graphics, GHS pictograms, full segregation tables, and synonym search. For another material, use the UN number and chemical lookup.

Reference data compiled from the DOT Hazardous Materials Table (49 CFR 172.101), the 2024 Emergency Response Guidebook, and public chemical databases (PubChem, NIOSH, EPA). Always verify the correct shipping description against the current regulation and the manufacturer's SDS Section 14 before shipping.