UN/NA Number Reference
DOT Class 5.1 Oxidizer placard

UN 2426: Ammonium nitrate, liquid

49 CFR 172.101 Hazardous Materials Table·ERG 2024

DOT Classification and Shipping

UN 2426 is assigned the proper shipping name Ammonium nitrate, liquid in the U.S. DOT Hazardous Materials Table (49 CFR 172.101). It is classified as a Class 5.1 Oxidizer material. Required label(s): 5.1.

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 140)

Hazards: May cause fire or explosion. May accelerate burning. May explode from heat or contamination.

Fire: Use flooding water. Cool containers. Do not use dry chemical on large fires (ineffective).

Spill: Keep combustibles away. Do not touch. Use water spray to reduce dust.

Chemical and Physical Properties

Ammonium nitrate is commercially available both as a colorless crystalline solid and processed into prills for specific applications. Soluble in water. Does not readily burn but will do so if contaminated with combustible material. Accelerates the burning of combustible material. Produces toxic oxides of nitrogen during combustion. Used to make fertilizers and explosives, and as a nutrient in producing antibiotics and yeast.

CAS Number: 6484-52-2
Molecular Formula: H4N2O3
Molecular Weight: 80.044 g/mol
Color / Form: White hygroscopic crystals; orthorhombic
Odor: Odorless
Boiling Point: -436 F
Melting Point: 337.8 °F (USCG, 1999)
Autoignition: Not flammable (USCG, 1999)
Specific Gravity: 1.72
Vapor Pressure: 2.3 kpa
Water Solubility: 213 g/100 g water at 25 °C
pH: 0.1 M solution in water: 5.43

Special Provisions

49 CFR 172.102 special provision codes for this entry: 148, B5, T7. 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 2426 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.